Sample records for residual heat friction

  1. Comparison of Frictional Heating Models

    SciTech Connect (OSTI)

    Davies, Nicholas R [ORNL; Blau, Peter Julian [ORNL

    2013-10-01T23:59:59.000Z

    The purpose of this work was to compare the predicted temperature rises using four well-known models for frictional heating under a few selected conditions in which similar variable inputs are provided to each model. Classic papers by Archard, Kuhlmann-Wilsdorf, Lim and Ashby, and Rabinowicz have been examined, and a spreadsheet (Excel ) was developed to facilitate the calculations. This report may be used in conjunction with that spreadsheet. It explains the background, assumptions, and rationale used for the calculations. Calculated flash temperatures for selected material combinations, under a range of applied loads and sliding speeds, are tabulated. The materials include AISI 52100 bearing steel, CDA 932 bronze, NBD 200 silicon nitride, Ti-6Al-4V alloy, and carbon-graphite material. Due to the assumptions made by the different models, and the direct way in which certain assumed quantities, like heat sink distances or asperity dimensions, enter into the calculations, frictional hearing results may differ significantly; however, they can be similar in certain cases in light of certain assumptions that are shared between the models.

  2. Neutron diffraction measurements of residual stresses in friction stir welding: a review

    SciTech Connect (OSTI)

    Woo, Wan Chuck [ORNL; Feng, Zhili [ORNL; Wang, Xun-Li [ORNL; David, Stan A [ORNL

    2011-01-01T23:59:59.000Z

    Significant amounts of residual stresses are often generated during welding and result in critical degradation of the structural integrity and performance of components. Neutron diffraction has become a well established technique for the determination of residual stresses in welds because of the unique deep penetration, three-dimensional mapping capability, and volume averaged bulk measurements characteristic of the scattering neutron beam. Friction stir welding has gained prominence in recent years. The authors reviewed a number of neutron diffraction measurements of residual stresses in friction stir welds and highlighted examples addressing how the microstructures and residual stresses are correlated with each other. An example of in situ neutron diffraction measurement result shows the evolution of the residual stresses during welding.

  3. Friction and Heat Transfer Characteristics of Silica and CNT Nanofluids in a Tube Flow

    E-Print Network [OSTI]

    Kostic, Milivoje M.

    Friction and Heat Transfer Characteristics of Silica and CNT Nanofluids in a Tube Flow MILIVOJE M of nanofluids in tube flow has been developed, instrumented and computerized. It has been calibrated using) nanofluids show peculiar results with substantial friction drag reduction and heat transfer enhancement

  4. Turbulent heat transfer and friction in a square channel with discrete rib turbulators

    E-Print Network [OSTI]

    McMillin, Robert Dale

    1989-01-01T23:59:59.000Z

    TURBULENT HEAT TRANSFER AND FRICTION IN A SQUARE CHANNEL WITH DISCRETE RIB TURBULATORS A Thesis by ROBERT DALE iXIGMILLIN Subniitted to the Office of Graduate Studies of Texas AK. M L niversrty in partial fulfillment of the requirements... for the degree of MASTER OF SGIE IGE Deceinber 1989 Major Subject' Mechanical Engineering TURBULENT HEAT TRANSFER AND FRICTION IN A SQUARE CHANNEL WITH DISCRETE RIB TURBULATORS A Thesrs by ROBERT DALE MCMILLI'V Approverl as to style and content...

  5. Heat transfer and friction characteristics of air flow in microtubes Chien-Yuh Yang a,

    E-Print Network [OSTI]

    Kandlikar, Satish

    Heat transfer and friction characteristics of air flow in microtubes Chien-Yuh Yang a, , Chia September 2011 Keywords: Microtube Heat transfer Liquid Crystal Thermography a b s t r a c t Several researches dealing with the single-phase forced convection heat transfer inside microchannels have been

  6. Alternative cooling resource for removing the residual heat of reactor

    SciTech Connect (OSTI)

    Park, H. C.; Lee, J. H.; Lee, D. S.; Jung, C. Y.; Choi, K. Y. [Korea Hydro and Nuclear Power Co., Ltd., 260 Naa-ri Yangnam-myeon Gyeongju-si, Gyeonasangbuk-do, 780-815 (Korea, Republic of)

    2012-07-01T23:59:59.000Z

    The Recirculated Cooling Water (RCW) system of a Candu reactor is a closed cooling system which delivers demineralized water to coolers and components in the Service Building, the Reactor Building, and the Turbine Building and the recirculated cooling water is designed to be cooled by the Raw Service Water (RSW). During the period of scheduled outage, the RCW system provides cooling water to the heat exchangers of the Shutdown Cooling System (SDCS) in order to remove the residual heat of the reactor, so the RCW heat exchangers have to operate at all times. This makes it very hard to replace the inlet and outlet valves of the RCW heat exchangers because the replacement work requires the isolation of the RCW. A task force was formed to prepare a plan to substitute the recirculated water with the chilled water system in order to cool the SDCS heat exchangers. A verification test conducted in 2007 proved that alternative cooling was possible for the removal of the residual heat of the reactor and in 2008 the replacement of inlet and outlet valves of the RCW heat exchangers for both Wolsong unit 3 and 4 were successfully completed. (authors)

  7. Studies of the frictional heating of polycrystalline diamond compact drag tools during rock cutting

    SciTech Connect (OSTI)

    Ortega, A.; Glowka, D.A.

    1982-06-01T23:59:59.000Z

    A numerical-analytical model is developed to analyze temperatures in polycrystalline diamond compact (PDC) drag tools subject to localized frictional heating at a worn flat area and convective cooling at exposed lateral surfaces. Experimental measurements of convective heat transfer coefficients of PDC cutters in a uniform crossflow are presented and used in the model to predict temperatures under typical drilling conditions with fluid flow. The analysis compares favorably with measurements of frictional temperatures in controlled cutting tests on Tennessee marble. It is found that average temperatures at the wearflat contact zone vary directly with frictional force per unit area and are proportional to the one-half power of the cutting speed at the velocities investigated. Temperatures are found to be much more sensitive to decreases in the dynamic friction by lubrication than to increases in convective cooling rates beyond currently achievable levels with water or drilling fluids. It is shown that use of weighted drilling fluids may actually decrease cooling rates compared to those achieved with pure water. It is doubtful that tool temperatures can be kept below critical levels (750/sup 0/C) if air is employed as the drilling fluid. The degree of tool wear is found to have a major influence on the thermal response of the friction contact zone, so that for equal heating per contact area, a worn tool will run much hotter than a sharp tool. It is concluded that tool temperatures may be kept below critical levels with conventional water or mud cooling as long as the fluid provides good cutter-rock lubrication.

  8. Nuclear reactor heat transport system component low friction support system

    DOE Patents [OSTI]

    Wade, Elman E. (Ruffs Dale, PA)

    1980-01-01T23:59:59.000Z

    A support column for a heavy component of a liquid metal fast breeder reactor heat transport system which will deflect when the pipes leading coolant to and from the heavy component expand or contract due to temperature changes includes a vertically disposed pipe, the pipe being connected to the heavy component by two longitudinally spaced cycloidal dovetail joints wherein the distal end of each of the dovetails constitutes a part of the surface of a large diameter cylinder and the centerlines of these large diameter cylinders intersect at right angles and the pipe being supported through two longitudinally spaced cycloidal dovetail joints wherein the distal end of each of the dovetails constitutes a part of the surface of a large diameter cylinder and the centerlines of these large diameter cylinders intersect at right angles, each of the cylindrical surfaces bearing on a flat and horizontal surface.

  9. Frictional heating and convective cooling of polycrystalline diamond drag tools during rock cutting

    SciTech Connect (OSTI)

    Ortega, A.; Glowka, D.A.

    1982-01-01T23:59:59.000Z

    A numerical-analytical model is developed to predict temperatures in stud-mounted polycrystalline diamond compact (PDC) drag tools during rock cutting. Experimental measurements of the convective heat transfer coefficient for PDC cutters are used in the model to predict temperatures under typical drilling conditions with fluid flow. The analysis compares favorably with measurements of frictional temperatures in controlled cutting tests on Tennessee marble. It is shown that mean cutter wearflat temperatures can be maintained below the critical value of 750{sup 0}C only under conditions of low friction at the cutter/rock interface. This is true, regardless of the level of convective cooling. In fact, a cooling limit is established above which increases in convective cooling do not further reduce cutter temperatures. The ability of liquid drilling fluids to reduce interface friction is thus shown to be far more important in preventing excessive temperatures than their ability to provide cutter cooling. Due to the relatively high interface friction developed under typical air drilling conditions, it is doubtful that temperatures can be kept subcritical at high rotary speeds in some formations when air is employed as the drilling fluid, regardless of the level of cooling achieved.

  10. Finite element residual stress analysis of induction heating bended ferritic steel piping

    SciTech Connect (OSTI)

    Kima, Jong Sung [Sunchon National University, 255 Jungang-ro, Sucheon, Jeonnam (Korea, Republic of); Kim, Kyoung-Soo; Oh, Young-Jin; Chang, Hyung-Young; Park, Heung-Bae [KEPCO E and C, Co., Ltd., 188, Kumi-ro, Seongnam, Kyounggi (Korea, Republic of)

    2014-10-06T23:59:59.000Z

    Recently, there is a trend to apply the piping bended by induction heating process to nuclear power plants. Residual stress can be generated due to thermo-mechanical mechanism during the induction heating bending process. It is well-known that the residual stress has important effect on crack initiation and growth. The previous studies have focused on the thickness variation. In part, some studies were performed for residual stress evaluation of the austenitic stainless steel piping bended by induction heating. It is difficult to find the residual stresses of the ferritic steel piping bended by the induction heating. The study assessed the residual stresses of induction heating bended ferriticsteel piping via finite element analysis. As a result, it was identified that high residual stresses are generated on local outersurface region of the induction heating bended ferritic piping.

  11. Heat transfer and friction in a square channel with one-wall or two-wall rib turbulators

    E-Print Network [OSTI]

    Huang, Jie Joy

    1991-01-01T23:59:59.000Z

    HEAT TRANSFER AND FRICTION IN A SQUARE CHANNEL WITH ONE-WAIL OR TWO-WAII RIB TURBULATORS A Thesis by JIE JOY HUANG Submitted to the Office of Graduate Studies of Texas A8rM University in partial fulfillment of the requirements for the degree... of Commit tee) D. Rhode (Member) . A. Hassan (Member) I W. Bradley (Head of Department) December 1991 ABSTRACT Heat Transfer and Friction in a Square Channel with One-Wall or Two-Wall Rib Turbulators. (December 1991) Jie Joy Huang, B. S...

  12. Heat transfer and friction characteristics in rectangular channels with rib turbulators

    SciTech Connect (OSTI)

    Han. J.C. (Texas A and M Univ., College Station (USA))

    1988-05-01T23:59:59.000Z

    The effect of the channel aspect ratio on the distribution of the local heat transfer coefficient in rectangular channels with two opposite ribbed walls (to simulate turbine airfoil cooling passages) was determined for a Reynolds number range of 10,000 to 60,000. The channel width-to-height ratios (W/H, ribs on side W) were 1/4, 1/2, 1, 2, and 4. The test channels were heated by passing current through thin, stainless steel foils instrumented with thermocouples. The local heat transfer coefficients on the ribbed side wall and on the smooth side wall of each test channel from the channel entrance to the fully developed regions were measured for two rib spacings (P/e = 10 and 20). The rib angle-of-attack was kept at 90 deg. The local data in the fully developed region were averaged and correlated, based on the heat transfer and friction similarity laws developed for ribbed channels, to cover the ranges of channel aspect ratio, rib spacing, rib height, and Reynolds number. The results compare well with the published data for flow in a square channel with two opposite ribbed walls. The correlations can be used in the design of turbine airfoil cooling passages.

  13. Effect of permeable ribs on heat transfer and friction in a rectangular channel

    SciTech Connect (OSTI)

    Hwang, J.J. [Chung-Hua Polytechnic Inst., Hsinchu (Taiwan, Province of China). Dept. of Mechanical Engineering; Liou, T.M. [National Tsing Hua Univ., Hsinchu (Taiwan, Province of China). Dept. of Power Mechanical Engineering

    1995-04-01T23:59:59.000Z

    To increase specific thrust and to reduce specific fuel consumption (SFC), high turbine entry gas temperature (1,400--1,600 C) has become the trend in advanced aero-engine design. Such a high gas temperature is far above the allowable metal temperature; therefore, turbine blades must be cooled in order to operate in the high gas temperature environment. Heat transfer and friction characteristics in a rectangular channel with perforated ribs arranged in-line on two opposite walls are investigated experimentally. Five perforated rib open-area ratios (0, 10, 22, 38, and 44%) and three rib pitch-to-height ratios (10, 15, and 20) are examined. The Reynolds number ranges from 5,000 to 50,000. The rib height-to-channel hydraulic diameter ratio and the channel aspect ratio are 0.081 and 4, respectively. Laser holographic interferometry is employed not only to measure the heat transfer coefficients of the ribbed wall but also to determine the rib apparent permeability. It is found that ribs with appropriate high open-area ratio and high Reynolds number are permeable, and the critical Reynolds number for evidence of flow permeability decreases with increasing rib open-area ratio. Results of local heat transfer coefficients further show that the permeable ribs have an advantage of obviating hot spots. Moreover, the duct with permeable ribs gives a higher thermal performance than that with solid ribs.

  14. RCS pressure under reduced inventory conditions following a loss of residual heat removal

    SciTech Connect (OSTI)

    Palmrose, D.E.; Hughes, E.D.; Johnsen, G.W.

    1992-01-01T23:59:59.000Z

    The thermal-hydraulic response of a closed-reactor coolant system to loss of residual heat removal (RHR) cooling is investigated. The processes examined include: core coolant boiling and steam generator reflux condensation, pressure increase on the primary side, heat transfer mechanisms on the steam generator primary and secondary sides, and effects of noncondensible gas on heat transfer processes.

  15. RCS pressure under reduced inventory conditions following a loss of residual heat removal

    SciTech Connect (OSTI)

    Palmrose, D.E.; Hughes, E.D.; Johnsen, G.W.

    1992-08-01T23:59:59.000Z

    The thermal-hydraulic response of a closed-reactor coolant system to loss of residual heat removal (RHR) cooling is investigated. The processes examined include: core coolant boiling and steam generator reflux condensation, pressure increase on the primary side, heat transfer mechanisms on the steam generator primary and secondary sides, and effects of noncondensible gas on heat transfer processes.

  16. Influence of viscous friction heating on the efficiency of columns operated under very high pressures

    SciTech Connect (OSTI)

    Gritti, Fabrice [University of Tennessee, Knoxville (UTK); Guiochon, Georges A [ORNL

    2009-01-01T23:59:59.000Z

    When columns packed with very fine particles are operated at high mobile phase velocities, the friction of the mobile phase percolating through the column bed generates heat. This heat dissipates along and across the column and axial and radial temperature gradients appear. The wall region of the column tends to be cooler than its center, and due to the influence of temperature on the mobile phase viscosity and on the equilibrium constant of analytes, the band velocity is not constant across the column. This radial heterogeneity of the temperature distribution across the column contributes to band broadening. This phenomenon was investigated assuming a cylindrically symmetrical column and using the general dispersion theory of Aris, which relates the height equivalent to the theoretical plate (HETP) contribution due to a radial heterogeneity of the column to the radial distribution of the linear velocities of a compound peak and to the radial distribution of its apparent dispersion coefficients in the column bed. The former is known from the temperature gradient across the column, the temperature dependencies of the mobile phase viscosity, and the retention factor of the compound. The latter is derived from the known expression of the transverse reduced HETP equation for the column. The values of the HETP calculated with the Aris model and a classical HETP equation were compared to those measured on a 2.1 x 50 mm Acquity BEH-C{sub 18} column, run at flow rates of 0.6, 0.95, 1.30, and 1.65 mL/min, with pure acetonitrile as the mobile phase and naphtho[2,3-a]pyrene as the retained compound. These two sets of data are in generally good agreement, although the experimental values of the HETP tend to increase faster with increasing mobile phase velocity than the calculated values.

  17. Nuclear reactor with makeup water assist from residual heat removal system

    DOE Patents [OSTI]

    Corletti, M.M.; Schulz, T.L.

    1993-12-07T23:59:59.000Z

    A pressurized water nuclear reactor uses its residual heat removal system to make up water in the reactor coolant circuit from an in-containment refueling water supply during staged depressurization leading up to passive emergency cooling by gravity feed from the refueling water storage tank, and flooding of the containment building. When depressurization commences due to inadvertence or a manageable leak, the residual heat removal system is activated manually and prevents flooding of the containment when such action is not necessary. Operation of the passive cooling system is not impaired. A high pressure makeup water storage tank is coupled to the reactor coolant circuit, holding makeup coolant at the operational pressure of the reactor. The staged depressurization system vents the coolant circuit to the containment, thus reducing the supply of makeup coolant. The level of makeup coolant can be sensed to trigger opening of successive depressurization conduits. The residual heat removal pumps move water from the refueling water storage tank into the coolant circuit as the coolant circuit is depressurized, preventing reaching the final depressurization stage unless the makeup coolant level continues to drop. The residual heat removal system can also be coupled in a loop with the refueling water supply tank, for an auxiliary heat removal path. 2 figures.

  18. Nuclear reactor with makeup water assist from residual heat removal system

    DOE Patents [OSTI]

    Corletti, Michael M. (New Kensington, PA); Schulz, Terry L. (Murrysville, PA)

    1993-01-01T23:59:59.000Z

    A pressurized water nuclear reactor uses its residual heat removal system to make up water in the reactor coolant circuit from an in-containment refueling water supply during staged depressurization leading up to passive emergency cooling by gravity feed from the refueling water storage tank, and flooding of the containment building. When depressurization commences due to inadvertence or a manageable leak, the residual heat removal system is activated manually and prevents flooding of the containment when such action is not necessary. Operation of the passive cooling system is not impaired. A high pressure makeup water storage tank is coupled to the reactor coolant circuit, holding makeup coolant at the operational pressure of the reactor. The staged depressurization system vents the coolant circuit to the containment, thus reducing the supply of makeup coolant. The level of makeup coolant can be sensed to trigger opening of successive depressurization conduits. The residual heat removal pumps move water from the refueling water storage tank into the coolant circuit as the coolant circuit is depressurized, preventing reaching the final depressurization stage unless the makeup coolant level continues to drop. The residual heat removal system can also be coupled in a loop with the refueling water supply tank, for an auxiliary heat removal path.

  19. Turbulent heat transfer and friction in a segmental channel that simulates leading-edge cooling channels of modern turbine blades

    E-Print Network [OSTI]

    Spence, Rodney Brian

    1995-01-01T23:59:59.000Z

    TURBULENT HEAT TRANSFER AND FRICTION IN A SEGMENTAL CkhQPKL THAT SIMULATES LEADING-EDGE COOLING C~LS OF MODERN TURBINE BLADES A Thesis by RODNEY BRIAN SPENCE Submitted to the Office of Graduate Studies of Texas A&M University m partial... Thesis by RODNEY BRIAN SPENCE Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved as to style and content by: S. C. Lau (Chair of Committee...

  20. In situ recovery from residually heated sections in a hydrocarbon containing formation

    DOE Patents [OSTI]

    Vinegar, Harold J. (Bellaire, TX); Karanikas, John Michael (Houston, TX); Ryan, Robert Charles (Houston, TX)

    2010-12-14T23:59:59.000Z

    Methods of treating a tar sands formation is described herein. The methods may include providing heat to a first section of a hydrocarbon layer in the formation from a plurality of heaters located in the first section of the formation. Heat is transferred from the heaters so that at least a first section of the formation reaches a selected temperature. At least a portion of residual heat from the first section transfers from the first section to a second section of the formation. At least a portion of hydrocarbons in the second section are mobilized by providing a solvation fluid and/or a pressurizing fluid to the second section of the formation.

  1. Simulation of Distortion and Residual Stress Development During Heat Treatment of Steel Castings

    SciTech Connect (OSTI)

    Christoph Beckermann; Kent Carlson

    2011-07-22T23:59:59.000Z

    Heat treatment and associated processing, such as quenching, are critical during high strength steel casting production. These processes must be managed closely to prevent thermal and residual stresses that may result in distortion, cracking (particularly after machining), re-work, and weld repair. The risk of casting distortion limits aggressive quenching that can be beneficial to the process and yield an improved outcome. As a result of these distortions, adjustments must be made to the casting or pattern design, or tie bars must be added. Straightening castings after heat treatments can be both time-consuming and expensive. Residual stresses may reduce a casting���¢��������s overall service performance, possibly resulting in catastrophic failure. Stress relieving may help, but expends additional energy in the process. Casting software is very limited in predicting distortions during heat treatment, so corrective measures most often involve a tedious trial-and-error procedure. An extensive review of existing heat treatment residual stress and distortion modeling revealed that it is vital to predict the phase transformations and microstructure of the steel along with the thermal stress development during heat treatment. After reviewing the state-of-the-art in heat treatment residual stress and distortion modeling, an existing commercial code was selected because of its advanced capabilities in predicting phase transformations, the evolving microstructure and related properties along with thermal stress development during heat treatment. However, this software was developed for small parts created from forgings or machined stock, and not for steel castings. Therefore, its predictive capabilities for heat treatment of steel castings were investigated. Available experimental steel casting heat treatment data was determined to be of insufficient detail and breadth, and so new heat treatment experiments were designed and performed, casting and heat treating modified versions of the Navy-C ring (a classical test shape for heat treatment experiments) for several carbon and low alloy steels in order to generate data necessary to validate the code. The predicted distortions were in reasonable agreement with the experimentally measured values. However, the final distortions in the castings were small, making it difficult to determine how accurate the predictions truly are. It is recommended that further validation of the software be performed with the aid of additional experiments with large production steel castings that experience significant heat treatment distortions. It is apparent from this research that the mechanical properties of the bonded sand used for cores and sand molds are key in producing accurate stress simulation results. Because of this, experiments were performed to determine the temperature-dependent elastic modulus of a resin-bonded sand commonly utilized in the steel casting industry. The elastic modulus was seen to vary significantly with heating and cooling rates. Also, the retained room temperature elastic modulus after heating was seen to degrade significantly when the sand was heated above 125�������°C. The elastic modulus curves developed in this work can readily be utilized in casting simulation software. Additional experiments with higher heating rates are recommended to determine the behavior of the elastic modulus in the sand close to the mold-metal interface. The commercial heat treatment residual stress and distortion code, once fully validated, is expected to result in an estimated energy savings of 2.15 trillion BTU���¢��������s/year. Along with these energy savings, reduction of scrap and improvement in casting yield will result in a reduction of the environmental emissions associated with the melting and pouring of the metal which will be saved as a result of this technology.

  2. Simulation of the loss of the residual heat removal of an integral test facility using computer code Cathare7

    E-Print Network [OSTI]

    Troshko, Andrey Arthurovich

    1996-01-01T23:59:59.000Z

    of the requirements for the degree of MASTER OF SCIENCE December 1996 Major Subject: Nuclear Engineering SIMULATION OF THE LOSS OF THE RESIDUAL HEAT REMOVAL OF AN INTEGRAL TEST FACILITY USING COMPUTER CODE CATHARE A Thesis by ANDREY ARTUROVICH TROSHKO.... (Head of Department) December 1996 Major Subject: Nuclear Engineering ABSTRACT Simulation of the Loss of the Residual Heat Removal of an Integral Test Facility Using Computer Code CATHARE. (December 1996) Andrey Arturovich Troshko, Diploma...

  3. Mitigation Measures Following a Loss-of-Residual-Heat-Removal Event During Shutdown

    SciTech Connect (OSTI)

    Seul, Kwang Won; Bang, Young Seok; Kim, Hho Jung [Korea Institute of Nuclear Safety (Korea, Republic of)

    2000-10-15T23:59:59.000Z

    The transient following a loss-of-residual-heat-removal event during shutdown was analyzed to determine the containment closure time (CCT) to prevent uncontrolled release of fission products and the gravity-injection path and rate (GIPR) for effective core cooling using the RELAP5/MOD3.2 code. The plant conditions of Yonggwang Units 3 and 4, a pressurized water reactor (PWR) of 2815-MW(thermal) power in Korea, were reviewed, and possible event sequences were identified. From the CCT analysis for the five cases of typical plant configurations, it was estimated for the earliest CCT to be 40 min after the event in a case with a large cold-leg opening and emptied steam generators (SGs). However, the case with water-filled SGs significantly delayed the CCT through the heat removal to the secondary side. From the GIPR analysis for the six possible gravity-injection paths from the refueling water storage tank (RWST), the case with the injection point and opening on the other leg side was estimated to be the most suitable path to avoid core boiling. In addition, from the sensitivity study, it was evaluated for the plant to be capable of providing the core cooling for the long-term transient if nominal RWST water is available. As a result, these analysis methods and results will provide useful information in understanding the plant behavior and preparing the mitigation measures after the event, especially for Combustion Engineering-type PWR plants. However, to directly apply the analysis results to the emergency procedure for such an event, additional case studies are needed for a wide range of operating conditions such as reactor coolant inventory, RWST water temperature, and core decay heat rate.

  4. Estimation of residual MSW heating value as a function of waste component recycling

    SciTech Connect (OSTI)

    Magrinho, Alexandre [Mechanical Engineering Department, Escola Superior de Tecnologia de Setubal, Campus IPS, Estefanilha, Setubal (Portugal); Semiao, Viriato [Mechanical Engineering Department, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1049-001 Lisbon (Portugal)], E-mail: ViriatoSemiao@ist.utl.pt

    2008-12-15T23:59:59.000Z

    Recycling of packaging wastes may be compatible with incineration within integrated waste management systems. To study this, a mathematical model is presented to calculate the fraction composition of residual municipal solid waste (MSW) only as a function of the MSW fraction composition at source and recycling fractions of the different waste materials. The application of the model to the Lisbon region yielded results showing that the residual waste fraction composition depends both on the packaging wastes fraction at source and on the ratio between that fraction and the fraction of the same material, packaging and non-packaging, at source. This behaviour determines the variation of the residual waste LHV. For 100% of paper packaging recycling, LHV reduces 4.2% whereas this reduction is of 14.4% for 100% of packaging plastics recycling. For 100% of food waste recovery, LHV increases 36.8% due to the moisture fraction reduction of the residual waste. Additionally the results evidence that the negative impact of recycling paper and plastic packaging on the LHV may be compensated by recycling food waste and glass and metal packaging. This makes packaging materials recycling and food waste recovery compatible strategies with incineration within integrated waste management systems.

  5. The impact of upper tropospheric friction and Gill-type heating on the location and strength of the Tropical Easterly Jet: Idealized physics in a dry Atmospheric General Circulation Model

    E-Print Network [OSTI]

    Rao, Samrat

    2015-01-01T23:59:59.000Z

    An atmospheric general circulation model (AGCM) with idealized and complete physics has been used to evaluate the Tropical Easterly Jet (TEJ) jet. In idealized physics, the role of upper tropospheric friction has been found to be important in getting realistic upper tropospheric zonal wind patterns in response to heating. In idealized physics, the location and strength of the TEJ as a response to Gill heating has been studied. Though the Gill model is considered to be widely successful in capturing the lower tropospheric response, it is found to be inadequate in explaining the location and strength of the upper level TEJ. Heating from the Gill model and realistic upper tropospheric friction does not lead to the formation of a TEJ.

  6. Friction Induced Skin Tags

    E-Print Network [OSTI]

    Allegue, Francisco; Fachal, Carmen; Pérez-Pérez, Lidia

    2008-01-01T23:59:59.000Z

    Duplantis KL, Jones BH. Friction blisters. Pathophysiology,Friction Induced Skin Tags Francisco Allegue MD 1 , Carmenetiopathogenic role for friction. Introduction Skin tags (

  7. Experimental Analysis of the Single-Phase Heat Transfer and Friction Factor inside the Horizontal Internally Micro-Fin Tube

    E-Print Network [OSTI]

    Ghajar, Afshin J.

    ; micro-fin tube I. INTRODUCTION Single-phase liquid flow in internally enhanced tubes is becoming more of tube is widely used in high flow rate applications because the heat transfer enhancement in high flow that the secondary flow inside the tube with longitudinal fins was insignificant in the laminar flow and the thermal

  8. Measurement of residual radioactive surface contamination by 2-D laser heated TLD

    SciTech Connect (OSTI)

    Jones, S.C.

    1997-06-01T23:59:59.000Z

    The feasibility of applying and adapting a two-dimensional laser heated thermoluminescence dosimetry system to the problem of surveying for radioactive surface contamination was studied. The system consists of a CO{sub 2} laser-based reader and monolithic arrays of thin dosimeter elements. The arrays consist of 10,201 thermoluminescent phosphor elements of 40 micron thickness, covering a 900 cm{sup 2} area. Array substrates are 125 micron thick polyimide sheets, enabling them to easily conform to regular surface shapes, especially for survey of surfaces that are inaccessible for standard survey instruments. The passive, integrating radiation detectors are sensitive to alpha and beta radiation at contamination levels below release guideline limits. Required contact times with potentially contaminated surfaces are under one hour to achieve detection of transuranic alpha emission at 100 dpm/100 cm{sup 2}. Positional information obtained from array evaluation is useful for locating contamination zones. Unique capabilities of this system for survey of sites, facilities and material include measurement inside pipes and other geometrical configurations that prevent standard surveys, and below-surface measurement of alpha and beta emitters in contaminated soils. These applications imply a reduction of material that must be classified as radioactive waste by virtue of its possibility of contamination, and cost savings in soil sampling at contaminated sites.

  9. Introduction Rolling and Friction

    E-Print Network [OSTI]

    Kuhn, Matthew R.

    Introduction Kinematics Solutions Rolling and Friction in Discrete Element Simulations Matthew R of rolling resistance Creep-friction definition Creep-friction vs. Cattaneo-Mindlin friction Classification / papers / EMI2011.pdf #12;Introduction Kinematics Solutions Classification of rolling resistance Creep-friction

  10. Modelling of the Effects of Friction and Compression on Explosives ESGI80 Modelling of the Effects of Friction and

    E-Print Network [OSTI]

    Purvis, Richard

    Modelling of the Effects of Friction and Compression on Explosives ESGI80 Modelling of the Effects of Friction and Compression on Explosives Problem presented by John Curtis Atomic Weapons Establishment, based on the compression of a sample of the explosive. The study group identified frictional heating

  11. Granular Brownian motion with dry friction

    E-Print Network [OSTI]

    A. Gnoli; A. Puglisi; H. Touchette

    2013-04-12T23:59:59.000Z

    The interplay between Coulomb friction and random excitations is studied experimentally by means of a rotating probe in contact with a stationary granular gas. The granular material is independently fluidized by a vertical shaker, acting as a 'heat bath' for the Brownian-like motion of the probe. Two ball bearings supporting the probe exert nonlinear Coulomb friction upon it. The experimental velocity distribution of the probe, autocorrelation function, and power spectra are compared with the predictions of a linear Boltzmann equation with friction, which is known to simplify in two opposite limits: at high collision frequency, it is mapped to a Fokker-Planck equation with nonlinear friction, whereas at low collision frequency, it is described by a sequence of independent random kicks followed by friction-induced relaxations. Comparison between theory and experiment in these two limits shows good agreement. Deviations are observed at very small velocities, where the real bearings are not well modeled by Coulomb friction.

  12. Quantum friction

    E-Print Network [OSTI]

    R. Tsekov

    2012-12-05T23:59:59.000Z

    The Brownian motion of a light quantum particle in a heavy classical gas is theoretically described and a new expression for the friction coefficient is obtained for arbitrary temperature. At zero temperature it equals to the de Broglie momentum of the mean free path divided by the mean free path. Alternatively, the corresponding mobility of the quantum particle in the classical gas is equal to the square of the mean free path divided by the Planck constant. The Brownian motion of a quantum particle in a quantum environment is also discussed.

  13. Roles of Dry Friction in Fluctuating Motion of Adiabatic Piston

    E-Print Network [OSTI]

    Tomohiko G. Sano; Hisao Hayakawa

    2014-03-08T23:59:59.000Z

    The motion of an adiabatic piston under dry friction is investigated to clarify the roles of dry friction in non-equilibrium steady states. We clarify that dry friction can reverse the direction of the piston motion and causes a discontinuity or a cusp-like singularity for velocity distribution functions of the piston. We also show that the heat fluctuation relation is modified under dry friction.

  14. Evaluation on double-wall-tube residual stress distribution of sodium-heated steam generator by neutron diffraction and numerical analysis

    SciTech Connect (OSTI)

    Kisohara, N. [Advanced Nuclear System Research and Development Directorate, Japan Atomic Energy Agency (Japan); Suzuki, H.; Akita, K. [Quantum Beam Science Directorate, Japan Atomic Energy Agency (Japan); Kasahara, N. [Dept. of Nuclear Engineering and Management, Univ. of Tokyo (Japan)

    2012-07-01T23:59:59.000Z

    A double-wall-tube is nominated for the steam generator heat transfer tube of future sodium fast reactors (SFRs) in Japan, to decrease the possibility of sodium/water reaction. The double-wall-tube consists of an inner tube and an outer tube, and they are mechanically contacted to keep the heat transfer of the interface between the inner and outer tubes by their residual stress. During long term SG operation, the contact stress at the interface gradually falls down due to stress relaxation. This phenomenon might increase the thermal resistance of the interface and degrade the tube heat transfer performance. The contact stress relaxation can be predicted by numerical analysis, and the analysis requires the data of the initial residual stress distributions in the tubes. However, unclear initial residual stress distributions prevent precious relaxation evaluation. In order to resolve this issue, a neutron diffraction method was employed to reveal the tri-axial (radius, hoop and longitudinal) initial residual stress distributions in the double-wall-tube. Strain gauges also were used to evaluate the contact stress. The measurement results were analyzed using a JAEA's structural computer code to determine the initial residual stress distributions. Based on the stress distributions, the structural computer code has predicted the transition of the relaxation and the decrease of the contact stress. The radial and longitudinal temperature distributions in the tubes were input to the structural analysis model. Since the radial thermal expansion difference between the inner (colder) and outer (hotter) tube reduces the contact stress and the tube inside steam pressure contributes to increasing it, the analytical model also took these effects into consideration. It has been conduced that the inner and outer tubes are contacted with sufficient stresses during the plant life time, and that effective heat transfer degradation dose not occur in the double-wall-tube SG. (authors)

  15. Vacuum friction in rotating particles

    E-Print Network [OSTI]

    A. Manjavacas; F. J. García de Abajo

    2010-09-21T23:59:59.000Z

    We study the frictional torque acting on particles rotating in empty space. At zero temperature, vacuum friction transforms mechanical energy into light emission and produces particle heating. However, particle cooling relative to the environment occurs at finite temperatures and low rotation velocities. Radiation emission is boosted and its spectrum significantly departed from a hot-body emission profile as the velocity increases. Stopping times ranging from hours to billions of years are predicted for materials, particle sizes, and temperatures accessible to experiment. Implications for the behavior of cosmic dust are discussed.

  16. Experimental studies on heat transfer and friction factor characteristics of Al{sub 2}O{sub 3}/water nanofluid in a circular pipe under laminar flow with wire coil inserts

    SciTech Connect (OSTI)

    Chandrasekar, M.; Suresh, S. [Department of Mechanical Engineering, National Institute of Technology, Tiruchirappalli 620015 (India); Chandra Bose, A. [Nanomaterials Laboratory, Department of Physics, National Institute of Technology, Tiruchirappalli 620015 (India)

    2010-02-15T23:59:59.000Z

    In this paper, fully developed laminar flow convective heat transfer and friction factor characteristics of Al{sub 2}O{sub 3}/water nanofluid flowing through a uniformly heated horizontal tube with and without wire coil inserts is presented. For this purpose, Al{sub 2}O{sub 3} nanoparticles of 43 nm size were synthesized, characterized and dispersed in distilled water to form stable suspension containing 0.1% volume concentration of nanoparticles. The Nusselt number in the fully developed region were measured and found to increase by 12.24% at Re = 2275 for plain tube with nanofluid compared to distilled water. Two wire coil inserts made of stainless steel with pitch ratios 2 and 3 were used which increased the Nusselt numbers by 15.91% and 21.53% respectively at Re = 2275 with nanofluid compared to distilled water. The better heat transfer performance of nanofluid with wire coil insert is attributed to the effects of dispersion or back-mixing which flattens the temperature distribution and make the temperature gradient between the fluid and wall steeper. The measured pressure loss with the use of nanofluids is almost equal to that of the distilled water. The empirical correlations developed for Nusselt number and friction factor in terms of Reynolds/Peclet number, pitch ratio and volume concentration fits with the experimental data within {+-}15%. (author)

  17. Gas-Cooled Fast Breeder Reactor Preliminary Safety Information Document, Amendment 10. GCFR residual heat removal system criteria, design, and performance

    SciTech Connect (OSTI)

    Not Available

    1980-09-01T23:59:59.000Z

    This report presents a comprehensive set of safety design bases to support the conceptual design of the gas-cooled fast breeder reactor (GCFR) residual heat removal (RHR) systems. The report is structured to enable the Nuclear Regulatory Commission (NRC) to review and comment in the licensability of these design bases. This report also presents information concerning a specific plant design and its performance as an auxiliary part to assist the NRC in evaluating the safety design bases.

  18. Friction in Mid-latitude Bob Plant, Stephen Belcher, Bob Beare, Andy Brown

    E-Print Network [OSTI]

    Plant, Robert

    Friction in Mid-latitude Cyclones Ian Boutle Bob Plant, Stephen Belcher, Bob Beare, Andy Brown #12;Motivation · Many studies have shown the significance of friction in formation and dissipation of cyclones Dt = + × . F . Diabatic Term: · Surface heat fluxes · Latent heat fluxes Frictional Term

  19. DRAINED RESIDUAL STRENGTH OF COHESIVE SOILSa

    E-Print Network [OSTI]

    that the residual friction angle is independent of the original shear strength, water content, and liquidity indexDRAINED RESIDUAL STRENGTH OF COHESIVE SOILSa Discussion by Robert W. Day,3 Fellow, ASCE The authors have preparcd an important paper on the drained residual shear strength of cohesive soil. The authors

  20. Skin friction blistering: computer model.

    E-Print Network [OSTI]

    Xing, Malcolm; Pan, Ning; Zhong, Wen; Maibach, Howard

    2007-01-01T23:59:59.000Z

    on blisters produced by friction. I. Results of linearDuplantis KL, Jones BH. Friction blisters. Pathophysiology,WA, Sulzberger MB. The friction blister. Mil Med 6. Cortese

  1. Frictional Widgets: Enhancing Touch Interfaces with Programmable Friction

    E-Print Network [OSTI]

    Levesque, Vincent

    Frictional Widgets: Enhancing Touch Interfaces with Programmable Friction Abstract Touch the design possibilities offered by augmenting touchscreens with programmable surface friction. Four exemplar of touch interactions can be enhanced when using a touchscreen with dynamically varied surface friction. We

  2. Velocity dependence of friction of confined polymers

    E-Print Network [OSTI]

    I. M. Sivebaek; V. N. Samoilov; B. N. J. Persson

    2009-11-18T23:59:59.000Z

    We present molecular dynamics friction calculations for confined hydrocarbon solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: (a) polymer sliding against a hard substrate, and (b) polymer sliding on polymer. We discuss the velocity dependence of the frictional shear stress for both cases. In our simulations, the polymer films are very thin (approx. 3 nm), and the solid walls are connected to a thermostat at a short distance from the polymer slab. Under these circumstances we find that frictional heating effects are not important, and the effective temperature in the polymer film is always close to the thermostat temperature. In the first setup (a), for hydrocarbons with molecular lengths from 60 to 1400 carbon atoms, the shear stresses are nearly independent of molecular length, but for the shortest hydrocarbon C20H42 the frictional shear stress is lower. In all cases the frictional shear stress increases monotonically with the sliding velocity. For polymer sliding on polymer [case (b)] the friction is much larger, and the velocity dependence is more complex. For hydrocarbons with molecular lengths from 60 to 140 C-atoms, the number of monolayers of lubricant increases (abruptly) with increasing sliding velocity (from 6 to 7 layers), leading to a decrease of the friction. Before and after the layering transition, the frictional shear stresses are nearly proportional to the logarithm of sliding velocity. For the longest hydrocarbon (1400 C-atoms) the friction shows no dependence on the sliding velocity, and for the shortest hydrocarbon (20 C-atoms) the frictional shear stress increases nearly linearly with the sliding velocity.

  3. Rubber friction: role of the flash temperature

    E-Print Network [OSTI]

    B. N. J. Persson

    2006-05-10T23:59:59.000Z

    When a rubber block is sliding on a hard rough substrate, the substrate asperities will exert time-dependent deformations of the rubber surface resulting in viscoelastic energy dissipation in the rubber, which gives a contribution to the sliding friction. Most surfaces of solids have roughness on many different length scales, and when calculating the friction force it is necessary to include the viscoelastic deformations on all length scales. The energy dissipation will result in local heating of the rubber. Since the viscoelastic properties of rubber-like materials are extremely strongly temperature dependent, it is necessary to include the local temperature increase in the analysis. At very low sliding velocity the temperature increase is negligible because of heat diffusion, but already for velocities of order 0.01 m/s the local heating may be very important. Here I study the influence of the local heating on the rubber friction, and I show that in a typical case the temperature increase results in a decrease in rubber friction with increasing sliding velocity for v > 0.01 m/s. This may result in stick-slip instabilities, and is of crucial importance in many practical applications, e.g., for the tire-road friction, and in particular for ABS-breaking systems.

  4. Rotational Quantum Friction

    E-Print Network [OSTI]

    Rongkuo Zhao; Alejandro Manjavacas; F. Javier García de Abajo; J. B. Pendry

    2012-09-25T23:59:59.000Z

    We investigate the frictional forces due to quantum fluctuations acting on a small sphere rotating near a surface. At zero temperature, we find the frictional force near a surface to be several orders of magnitude larger than that for the sphere rotating in vacuum. For metallic materials with typical conductivity, quantum friction is maximized by matching the frequency of rotation with the conductivity. Materials with poor conductivity are favored to obtain large quantum frictions. For semiconductor materials that are able to support surface plasmon polaritons, quantum friction can be further enhanced by several orders of magnitude due to the excitation of surface plasmon polaritons.

  5. Nanotribology and Nanoscale Friction

    SciTech Connect (OSTI)

    Guo, Yi [Stevens Institute of Technology, Hoboken, New Jersey; Qu, Zhihua [University of Central Florida, Orlando; Braiman, Yehuda [ORNL; Zhang, Zhenyu [ORNL; Barhen, Jacob [ORNL

    2008-01-01T23:59:59.000Z

    Tribology is the science and technology of contacting solid surfaces in relative motion, including the study of lubricants, lubrication, friction, wear, and bearings. It is estimated that friction and wear cost the U.S. economy 6% of the gross national product (Persson, 2000). For example, 5% of the total energy generated in an automobile engine is lost to frictional resistance. The study of nanoscale friction has a technological impact in reducing energy loss in machines, in microelectromechanical systems (MEMS), and in the development of durable, low-friction surfaces and ultra-thin lubrication films.

  6. Micromachine friction test apparatus

    DOE Patents [OSTI]

    deBoer, Maarten P. (Albuquerque, NM); Redmond, James M. (Albuquerque, NM); Michalske, Terry A. (Cedar Crest, NM)

    2002-01-01T23:59:59.000Z

    A microelectromechanical (MEM) friction test apparatus is disclosed for determining static or dynamic friction in MEM devices. The friction test apparatus, formed by surface micromachining, is based on a friction pad supported at one end of a cantilevered beam, with the friction pad overlying a contact pad formed on the substrate. A first electrostatic actuator can be used to bring a lower surface of the friction pad into contact with an upper surface of the contact pad with a controlled and adjustable force of contact. A second electrostatic actuator can then be used to bend the cantilevered beam, thereby shortening its length and generating a relative motion between the two contacting surfaces. The displacement of the cantilevered beam can be measured optically and used to determine the static or dynamic friction, including frictional losses and the coefficient of friction between the surfaces. The test apparatus can also be used to assess the reliability of rubbing surfaces in MEM devices by producing and measuring wear of those surfaces. Finally, the friction test apparatus, which is small in size, can be used as an in situ process quality tool for improving the fabrication of MEM devices.

  7. Friction Stir Welding of Hydrided Titanium Alloys Mark Taylor, D.P. Field

    E-Print Network [OSTI]

    Collins, Gary S.

    Friction Stir Welding of Hydrided Titanium Alloys Mark Taylor, D.P. Field Multi-Scale Engineering for Undergraduates program under grant number EEC-0754370 During Friction Stir Welding (FSW), a non-consumable tool-state welding process, much frictional heating and force is required of the tool. This steep demand on the tool

  8. Theory of Quantum Friction

    E-Print Network [OSTI]

    Mario G. Silveirinha

    2014-06-09T23:59:59.000Z

    Here, we develop a comprehensive quantum theory for the phenomenon of quantum friction. Based on a theory of macroscopic quantum electrodynamics for unstable systems, we calculate the quantum expectation of the friction force, and link the friction effect to the emergence of system instabilities related to the Cherenkov effect. These instabilities may occur due to the hybridization of particular guided modes supported by the individual moving bodies, and selection rules for the interacting modes are derived. It is proven that the quantum friction effect can take place even when the interacting bodies are lossless and made of nondispersive dielectrics.

  9. Friction in Forming of UD Composites

    SciTech Connect (OSTI)

    Sachs, U.; Haanappel, S. P. [Thermoplastic Composite Research Center, University of Twente, Horst building, P.O. Box 217, 7500AE Enschede (Netherlands); Akkerman, R. [Faculty of Engineering Technology, University of Twente, P.O. Box 217, 7500AE Enschede (Netherlands); Thermoplastic Composite Research Center, University of Twente, Horst building, P.O. Box 217, 7500AE Enschede (Netherlands); Thije, R. H. W. ten [Aniform Virtual Forming, Nieuwstraat 116, 7411 LP Deventer (Netherlands); Rooij, M. B. de [Faculty of Engineering Technology, University of Twente, P.O. Box 217, 7500AE Enschede (Netherlands)

    2011-05-04T23:59:59.000Z

    Inter-ply and tool/ply friction play a dominant role in hot stamp forming of UD fiber-reinforced thermoplastic laminates. This research treats friction measurements of a PEEK-AS4 composite system. To this end, an in-house developed friction tester is utilized to pull a laminate through two heat controlled clamping platens. The friction coefficient is determined by relating the clamp force to the pull force. The geometry of the gap between the clamping platens is monitored with micrometer accuracy. A first approach to describe the relation between the geometry and frictional behavior is undertaken by applying a standard thin-film theory for hydrodynamic lubrication. Experimental measurements showed that the thin-film theory does not entirely cover the underlying physics. Thus a second model is utilized, which employs a Leonov-model to describe the shear deformation of the matrix material, while its viscosity is described with a multi-mode Maxwell model. The combination of both models shows the potential to capture the complete frictional behavior.

  10. Skin friction blistering: computer model.

    E-Print Network [OSTI]

    Xing, Malcolm; Pan, Ning; Zhong, Wen; Maibach, Howard

    2007-01-01T23:59:59.000Z

    K. L.Jones, B. H. , Friction blisters. Pathophysiology,and M.B. Sulzberger, The friction blister. Mil Med, 1972.on blisters produced by friction. II. The blister fluid. J

  11. Factors affecting piston ring friction

    E-Print Network [OSTI]

    Liao, Kai, Ph. D. Massachusetts Institute of Technology

    2013-01-01T23:59:59.000Z

    The piston ring pack friction is a major contributor to the internal combustion engine mechanical friction loss. The oil control ring decides the oil supply to the top two rings in addition to being the major friction ...

  12. Effect of rib spacing on heat transfer and friction in a rotating two-pass rectangular (AR=1:2) channel 

    E-Print Network [OSTI]

    Liu, Yao-Hsien

    2006-10-30T23:59:59.000Z

    The research focuses on testing the heat transfer enhancement in a channel for different spacing of the rib turbulators. Those ribs are put on the surface in the two pass rectangular channel with an aspect ratio of AR=1:2. The cross section...

  13. Static Friction Phenomena The following static friction phenomena have a direct dependency on velocity.

    E-Print Network [OSTI]

    Simpkins, Alex

    Coulomb Friction Viscous Friction Stribeck Friction Static Friction Phenomena The following static friction phenomena have a direct dependency on velocity. Static Friction Model: Friction force opposes the direction of motion when the sliding velocity is zero. Coulomb Friction Model: Friction force

  14. Friction stir welding tool

    DOE Patents [OSTI]

    Tolle, Charles R. (Idaho Falls, ID); Clark, Denis E. (Idaho Falls, ID); Barnes, Timothy A. (Ammon, ID)

    2008-04-15T23:59:59.000Z

    A friction stir welding tool is described and which includes a shank portion; a shoulder portion which is releasably engageable with the shank portion; and a pin which is releasably engageable with the shoulder portion.

  15. Journal of Enhanced Heat Transfer, 19 (5): 457476 (2012) EXPERIMENTAL INVESTIGATION OF HEAT

    E-Print Network [OSTI]

    Ghajar, Afshin J.

    2012-01-01T23:59:59.000Z

    Journal of Enhanced Heat Transfer, 19 (5): 457­476 (2012) EXPERIMENTAL INVESTIGATION OF HEAT microfin tubes, most of the heat transfer and friction factor studies were focused on the turbulent region. However, there is a lack of information about the heat transfer and friction factor behavior of microfin

  16. Nonlinear Dynamics of Dry Friction

    E-Print Network [OSTI]

    Franz-Josef Elmer

    1997-07-01T23:59:59.000Z

    The dynamical behavior caused by dry friction is studied for a spring-block system pulled with constant velocity over a surface. The dynamical consequences of a general type of phenomenological friction law (stick-time dependent static friction, velocity dependent kinetic friction) are investigated. Three types of motion are possible: Stick-slip motion, continuous sliding, and oscillations without sticking events. A rather complete discussion of local and global bifurcation scenarios of these attractors and their unstable counterparts is present.

  17. Nonlinear friction in quantum mechanics

    E-Print Network [OSTI]

    Roumen Tsekov

    2013-03-10T23:59:59.000Z

    The effect of nonlinear friction forces in quantum mechanics is studied via dissipative Madelung hydrodynamics. A new thermo-quantum diffusion equation is derived, which is solved for the particular case of quantum Brownian motion with a cubic friction. It is extended also by a chemical reaction term to describe quantum reaction-diffusion systems with nonlinear friction as well.

  18. PEBBLES Simulation of Static Friction and New Static Friction Benchmark

    SciTech Connect (OSTI)

    Joshua J. Cogliati; Abderrafi M. Ougouag

    2010-05-01T23:59:59.000Z

    Pebble bed reactors contain large numbers of spherical fuel elements arranged randomly. Determining the motion and location of these fuel elements is required for calculating certain parameters of pebble bed reactor operation. This paper documents the PEBBLES static friction model. This model uses a three dimensional differential static friction approximation extended from the two dimensional Cundall and Strack model. The derivation of determining the rotational transformation of pebble to pebble static friction force is provided. A new implementation for a differential rotation method for pebble to container static friction force has been created. Previous published methods are insufficient for pebble bed reactor geometries. A new analytical static friction benchmark is documented that can be used to verify key static friction simulation parameters. This benchmark is based on determining the exact pebble to pebble and pebble to container static friction coefficients required to maintain a stable five sphere pyramid.

  19. Solid friction between soft filaments

    E-Print Network [OSTI]

    Ward, Andrew; Schwenger, Walter; Welch, David; Lau, A W C; Vitelli, Vincenzo; Mahadevan, L; Dogic, Zvonimir

    2015-01-01T23:59:59.000Z

    Any macroscopic deformation of a filamentous bundle is necessarily accompanied by local sliding and/or stretching of the constituent filaments. Yet the nature of the sliding friction between two aligned filaments interacting through multiple contacts remains largely unexplored. Here, by directly measuring the sliding forces between two bundled F-actin filaments, we show that these frictional forces are unexpectedly large, scale logarithmically with sliding velocity as in solid-like friction, and exhibit complex dependence on the filaments' overlap length. We also show that a reduction of the frictional force by orders of magnitude, associated with a transition from solid-like friction to Stokes' drag, can be induced by coating F-actin with polymeric brushes. Furthermore, we observe similar transitions in filamentous microtubules and bacterial flagella. Our findings demonstrate how altering a filament's elasticity, structure and interactions can be used to engineer interfilament friction and thus tune the prop...

  20. Solid friction between soft filaments

    E-Print Network [OSTI]

    Andrew Ward; Feodor Hilitski; Walter Schwenger; David Welch; A. W. C. Lau; Vincenzo Vitelli; L. Mahadevan; Zvonimir Dogic

    2015-03-04T23:59:59.000Z

    Any macroscopic deformation of a filamentous bundle is necessarily accompanied by local sliding and/or stretching of the constituent filaments. Yet the nature of the sliding friction between two aligned filaments interacting through multiple contacts remains largely unexplored. Here, by directly measuring the sliding forces between two bundled F-actin filaments, we show that these frictional forces are unexpectedly large, scale logarithmically with sliding velocity as in solid-like friction, and exhibit complex dependence on the filaments' overlap length. We also show that a reduction of the frictional force by orders of magnitude, associated with a transition from solid-like friction to Stokes' drag, can be induced by coating F-actin with polymeric brushes. Furthermore, we observe similar transitions in filamentous microtubules and bacterial flagella. Our findings demonstrate how altering a filament's elasticity, structure and interactions can be used to engineer interfilament friction and thus tune the properties of fibrous composite materials.

  1. Friction surfaced Stellite6 coatings

    SciTech Connect (OSTI)

    Rao, K. Prasad; Damodaram, R. [Department of Metallurgical and Materials Engineering - Indian Institute of Technology Madras, Chennai 600 036 (India); Rafi, H. Khalid, E-mail: khalidrafi@gmail.com [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India); Ram, G.D. Janaki [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India); Reddy, G. Madhusudhan [Metal Joining Group, Defence Metallurgical Research Laboratory (DMRL) Kanchanbagh, Hyderabad 500 058 (India); Nagalakshmi, R. [Welding Research Institute, Bharat Heavy Electricals Limited, Tiruchirappalli 620 014 (India)

    2012-08-15T23:59:59.000Z

    Solid state Stellite6 coatings were deposited on steel substrate by friction surfacing and compared with Stellite6 cast rod and coatings deposited by gas tungsten arc and plasma transferred arc welding processes. Friction surfaced coatings exhibited finer and uniformly distributed carbides and were characterized by the absence of solidification structure and compositional homogeneity compared to cast rod, gas tungsten arc and plasma transferred coatings. Friction surfaced coating showed relatively higher hardness. X-ray diffraction of samples showed only face centered cubic Co peaks while cold worked coating showed hexagonally close packed Co also. - Highlights: Black-Right-Pointing-Pointer Stellite6 used as coating material for friction surfacing. Black-Right-Pointing-Pointer Friction surfaced (FS) coatings compared with casting, GTA and PTA processes. Black-Right-Pointing-Pointer Finer and uniformly distributed carbides in friction surfaced coatings. Black-Right-Pointing-Pointer Absence of melting results compositional homogeneity in FS Stellite6 coatings.

  2. Internal Heat Transfer Coefficient Determination in a Packed Bed From the Transient Response Due to Solid Phase Induction Heating

    E-Print Network [OSTI]

    Geb, David; Zhou, Feng; Catton, Ivan

    2012-01-01T23:59:59.000Z

    the Hydraulic Drag and Heat Transfer Coefficients in Porous5] Locke, G. L. , 1950, “Heat Transfer and Flow FrictionA. P. , 1993, “Heat Transfer and Hydraulic Resistance in

  3. Numerical Estimation of Frictional Torques with Rate and State Friction

    E-Print Network [OSTI]

    Arun K. Singh; T. N. Singh

    2015-01-20T23:59:59.000Z

    In this paper, numerical estimation of frictional torques is carried out of a rotary elastic disc on a hard and rough surface under different rotating conditions. A one dimensional spring- mass rotary system is numerically solved under the quasistatic condition with the rate and state dependent friction model. It is established that torque of frictional strength as well as torque of steady dynamic stress increases with radius and found to be maximum at the periphery of the disc. Torque corresponding to frictional strength estimated using the analytical solution matches closely with the simulation only in the case of high stiffness of the connecting spring. In steady relaxation simulation, a steadily rotating disc is suddenly stopped and relaxational angular velocity and corresponding frictional torque decreases with both steady angular velocity and stiffness of the connecting spring in the velocity strengthening regime. In velocity weakening regime, in contrast, torque of relaxation stress deceases but relaxation velocity increases. The reason for the contradiction is explained.

  4. Irreversible work and inner friction in quantum thermodynamic processes

    E-Print Network [OSTI]

    F. Plastina; A. Alecce; T. J. G. Apollaro; G. Falcone; G. Francica; F. Galve; N. Lo Gullo; R. Zambrini

    2014-07-24T23:59:59.000Z

    We discuss the thermodynamics of closed quantum systems driven out of equilibrium by a change in a control parameter and undergoing a unitary process. We compare the work actually done on the system with the one that would be performed along ideal adiabatic and isothermal transformations. The comparison with the latter leads to the introduction of irreversible work, while that with the former leads to the introduction of inner friction. We show that these two quantities can be treated on equal footing, as both can be linked with the heat exchanged in thermalization processes and both can be expressed as relative entropies. Furthermore, we show that a specific fluctuation relation for the entropy production associated with the inner friction exists, which allows the inner friction to be written in terms of its cumulants.

  5. REDUCED ENGINE FRICTION AND WEAR

    SciTech Connect (OSTI)

    Ron Matthews

    2005-05-01T23:59:59.000Z

    This Final Technical Report discusses the progress was made on the experimental and numerical tasks over the duration of this project regarding a new technique for decreasing engine friction and wear via liner rotation. The experimental subtasks involved quantifying the reduction in engine friction for a prototype rotating liner engine relative to a comparable baseline engine. Both engine were single cylinder conversions of nominally identical production four-cylinder engines. Hot motoring tests were conducted initially and revealed that liner rotation decreased engine friction by 20% under motoring conditions. A well-established model was used to estimate that liner rotation should decrease the friction of a four-cylinder engine by 40% under hot motoring conditions. Hot motoring tear-down tests revealed that the crankshaft and valve train frictional losses were essentially the same for the two engines, as expected. However, the rotating liner engine had much lower (>70%) piston assembly friction compared to the conventional engine. Finally, we used the Instantaneous IMEP method to compare the crank-angle resolved piston assembly friction for the two engines. Under hot motoring conditions, these measurements revealed a significant reduction in piston assembly friction, especially in the vicinity of compression TDC when the lubrication regime transitions from hydrodynamic through mixed and into boundary friction. We have some remaining problems with these measurements that we expect to solve during the next few weeks. We will then perform these measurements under firing conditions. We also proposed to improve the state-of-the-art of numerical modeling of piston assembly friction for conventional engines and then to extend this model to rotating liner engines. Our research team first modeled a single ring in the Purdue ring-liner test rig. Our model showed good agreement with the test rig data for a range of speeds and loads. We then modeled a complete piston assembly in an engine. The model appears to produce the correct behavior, but we cannot quantify its strengths or weaknesses until our crank-angle-resolved measurements have been completed. Finally, we proposed and implemented a model for the effects of liner rotation on piston assembly friction. Here, we propose that the rotating liner design is analogous to the shaft-bushing mechanism. Therefore, we used the side-slip rolling friction model to simulate the effects of liner rotation. This model appears to be promising, but final analysis of its strengths and/or weaknesses must await our crank-angle-resolved measurements.

  6. Implications of Strong-Rate-Weakening Friction

    E-Print Network [OSTI]

    Greer, Julia R.

    Implications of Strong-Rate- Weakening Friction for the Length-Scale Dependence of the Strength · Rapid transitions between high static friction and very low dynamic friction · Leads to slip-pulse rupture · Slip pulses are extremely localized and have strong positive feedback between friction and slip

  7. Rubber friction and tire dynamics

    E-Print Network [OSTI]

    B. N. J. Persson

    2010-07-16T23:59:59.000Z

    We propose a simple rubber friction law, which can be used, e.g., in models of tire (and vehicle) dynamics. The friction law is tested by comparing numerical results to the full rubber friction theory (B.N.J. Persson, J. Phys.: Condensed Matter 18, 7789 (2006)). Good agreement is found between the two theories. We describe a two-dimensional (2D) tire model which combines the rubber friction model with a simple mass-spring description of the tire body. The tire model is very flexible and can be used to calculate accurate mu-slip (and the self-aligning torque) curves for braking and cornering or combined motion (e.g., braking during cornering). We present numerical results which illustrate the theory. Simulations of Anti-Blocking System (ABS) braking are performed using two simple control algorithms.

  8. Fusion Residues

    E-Print Network [OSTI]

    Kenneth Intriligator

    1991-08-19T23:59:59.000Z

    We discuss when and how the Verlinde dimensions of a rational conformal field theory can be expressed as correlation functions in a topological LG theory. It is seen that a necessary condition is that the RCFT fusion rules must exhibit an extra symmetry. We consider two particular perturbations of the Grassmannian superpotentials. The topological LG residues in one perturbation, introduced by Gepner, are shown to be a twisted version of the $SU(N)_k$ Verlinde dimensions. The residues in the other perturbation are the twisted Verlinde dimensions of another RCFT; these topological LG correlation functions are conjectured to be the correlation functions of the corresponding Grassmannian topological sigma model with a coupling in the action to instanton number.

  9. Engine Friction Reduction Through Surface Finish and Coatings...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Friction Reduction Through Surface Finish and Coatings Engine Friction Reduction Through Surface Finish and Coatings Opportunities exist for friction reduction in piston rings and...

  10. Friction Anisotropy: A unique and intrinsic property of decagonal quasicrystals

    E-Print Network [OSTI]

    Park, Jeong Young

    2008-01-01T23:59:59.000Z

    Quasi-Crystalline Low-Friction Coatings. Journal ofContact Mechanics, Friction and Adhesion with Application toEds. ), Fundamentals of Friction and Wear, Springer Berlin

  11. Epistemic Friction: Reflections on Knowledge, Truth, and Logic

    E-Print Network [OSTI]

    Sher, Gila

    2010-01-01T23:59:59.000Z

    ARTICLE Epistemic Friction: Re?ections on Knowledge, Truth,requires both freedom and friction. Freedom to set up ourprograms, etc. , and friction (constraint) coming from two

  12. Thermal Modeling of A Friction Bonding Process

    SciTech Connect (OSTI)

    John Dixon; Douglas Burkes; Pavel Medvedev

    2007-10-01T23:59:59.000Z

    A COMSOL model capable of predicting temperature evolution during nuclear fuel fabrication is being developed at the Idaho National Laboratory (INL). Fuel plates are fabricated by friction bonding (FB) uranium-molybdenum (U-Mo) alloy foils positioned between two aluminum plates. The ability to predict temperature distribution during fabrication is imperative to ensure good quality bonding without inducing an undesirable chemical reaction between U-Mo and aluminum. A three-dimensional heat transfer model of the FB process implementing shallow pin penetration for cladding monolithic nuclear fuel foils is presented. Temperature distribution during the FB process as a function of fabrication parameters such as weld speed, tool load, and tool rotational frequency are predicted. Model assumptions, settings, and equations are described in relation to standard friction stir welding. Current experimental design for validation and calibration of the model is also demonstrated. Resulting experimental data reveal the accuracy in describing asymmetrical temperature distributions about the tool face. Temperature of the bonded plate drops beneath the pin and is higher on the advancing side than the retreating side of the tool.

  13. Friction between Ring Polymer Brushes

    E-Print Network [OSTI]

    A. Erbas; J. Paturej

    2015-01-07T23:59:59.000Z

    Friction between ring-polymer brushes at melt densities sliding past each other are studied using extensive course-grained molecular dynamics simulations and scaling arguments, and the results are compared to the friction between linear-polymer brushes. We show that for a velocity range spanning over three decades, the frictional forces measured for ring-polymer brushes are half the corresponding friction in case of linear brushes. In the linear-force regime, the weak inter-digitation of two ring brushes compared to linear brushes also leads to a lower number of binary collisions between the monomers of opposing brushes. At high velocities, where the thickness of the inter-digitation layer between two opposing brushes is on the order monomer size regardless of brush topology, stretched segments of ring polymers take a double-stranded conformation. As a result, monomers of the double-stranded segments collide less with the monomers of the opposing ring brush even though a similar number of monomers occupies the inter-digitation layer for ring and linear-brush bilayers. The numerical data obtained from our simulations is consistent with the proposed scaling analysis. Conformation-dependent frictional reduction observed in ring brushes can have important consequences in non-equilibrium bulk systems.

  14. Rubber friction on ice and snow surfaces 

    E-Print Network [OSTI]

    Skouvaklis, Gerasimos

    2011-06-28T23:59:59.000Z

    The friction of rubber on ice and snow surfaces is complex. Deeper scientific understanding is important for optimising performance of tyres in winter. Rubber, ice and snow systems exhibit frictional behaviour which ...

  15. The Power of Friction: Quantifying the ``Goodness'' of Frictional Grasps \\Lambda

    E-Print Network [OSTI]

    Mishra, Bud

    The Power of Friction: Quantifying the ``Goodness'' of Frictional Grasps \\Lambda Marek Teichmann of fingers, coefficient of friction and the the goodness of a grasp. In particular, we give a general framework for defining a grasp metric that takes friction into account. Our approach rectifies a flaw

  16. Steam turbine: Alternative emergency drive for the secure removal of residual heat from the core of light water reactors in ultimate emergency situation

    SciTech Connect (OSTI)

    Souza Dos Santos, R. [Instituto de Engenharia Nuclear CNEN/IEN, Cidade Universitaria, Rua Helio de Almeida, 75 - Ilha do Fundiao, 21945-970 Rio de Janeiro (Brazil); Instituto Nacional de Ciencia e Tecnologia de Reatores Nucleares Inovadores / CNPq (Brazil)

    2012-07-01T23:59:59.000Z

    In 2011 the nuclear power generation has suffered an extreme probation. That could be the meaning of what happened in Fukushima Nuclear Power Plants. In those plants, an earthquake of 8.9 on the Richter scale was recorded. The quake intensity was above the trip point of shutting down the plants. Since heat still continued to be generated, the procedure to cooling the reactor was started. One hour after the earthquake, a tsunami rocked the Fukushima shore, degrading all cooling system of plants. Since the earthquake time, the plant had lost external electricity, impacting the pumping working, drive by electric engine. When operable, the BWR plants responded the management of steam. However, the lack of electricity had degraded the plant maneuvers. In this paper we have presented a scheme to use the steam as an alternative drive to maintain operable the cooling system of nuclear power plant. This scheme adds more reliability and robustness to the cooling systems. Additionally, we purposed a solution to the cooling in case of lacking water for the condenser system. In our approach, steam driven turbines substitute electric engines in the ultimate emergency cooling system. (authors)

  17. Pulling by Pushing, Slip with Infinite Friction,

    E-Print Network [OSTI]

    Pulling by Pushing, Slip with Infinite Friction, and Perfectly Rough Surfaces Kevin M. Lynch the two objects even with an infinite coefficient of friction. Thus the common conception that infinite friction prevents slip is in error. This paper shows examples of the phenomena with both quasi

  18. The friction of wrinkles Hamid Mohammadi1

    E-Print Network [OSTI]

    Mueser, Martin

    The friction of wrinkles Hamid Mohammadi1 and Martin H. M¨user2 1 Dept. of Applied Mathematics pattern has asymmetries not present in the counterbody. The instabilities then cause Coulomb's friction Likewise, the presence of friction - as observed for the much investigated keratocytes on silicon rubber15

  19. Friction in full view A. P. Merklea

    E-Print Network [OSTI]

    Marks, Laurence D.

    Friction in full view A. P. Merklea and L. D. Marksb Materials Science and Engineering proposed friction mechanisms explaining the unique tribological properties of graphite. Wear of graphite chemical or struc- tural information from the interface during a friction experi- ment. Examples

  20. Automotive friction-induced noises A. Elmaiana

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Automotive friction-induced noises A. Elmaiana , J.-M. Duffala , F. Gautiera , C. Pezeratb and J, France 3143 #12;Friction-induced noises are numerous in the automotive field. They also involve a large friction-induced noises with simple structures and automotive materials. Qualitative sensitivity studies

  1. Dynamical friction on satellite galaxies

    E-Print Network [OSTI]

    Michiko Fujii; Yoko Funato; Junichiro Makino

    2006-06-23T23:59:59.000Z

    For a rigid model satellite, Chandrasekhar's dynamical friction formula describes the orbital evolution quite accurately, when the Coulomb logarithm is chosen appropriately. However, it is not known if the orbital evolution of a real satellite with the internal degree of freedom can be described by the dynamical friction formula. We performed N-body simulation of the orbital evolution of a self-consistent satellite galaxy within a self-consistent parent galaxy. We found that the orbital decay of the simulated satellite is significantly faster than the estimate from the dynamical friction formula. The main cause of this discrepancy is that the stars stripped out of the satellite are still close to the satellite, and increase the drag force on the satellite through two mechanisms. One is the direct drag force from particles in the trailing tidal arm, a non-axisymmetric force that slows the satellite down. The other is the indirect effect that is caused by the particles remaining close to the satellite after escape. The force from them enhances the wake caused in the parent galaxy by dynamical friction, and this larger wake in turn slows the satellite down more than expected from the contribution of its bound mass. We found these two have comparable effects, and the combined effect can be as large as 20% of the total drag force on the satellite.

  2. Friction forces in cosmological models

    E-Print Network [OSTI]

    Donato Bini; Andrea Geralico; Daniele Gregoris; Sauro Succi

    2014-08-23T23:59:59.000Z

    We investigate the dynamics of test particles undergoing friction forces in a Friedmann-Robertson-Walker (FRW) spacetime. The interaction with the background fluid is modeled by introducing a Poynting-Robertson-like friction force in the equations of motion, leading to measurable (at least in principle) deviations of the particle trajectories from geodesic motion. The effect on the peculiar velocities of the particles is investigated for various equations of state of the background fluid and different standard cosmological models. The friction force is found to have major effects on particle motion in closed FRW universes, where it turns the time-asymptotic value (approaching the recollapse) of the peculiar particle velocity from ultra-relativistic (close to light speed) to a co-moving one, i.e., zero peculiar speed. On the other hand, for open or flat universes the effect of the friction is not so significant, because the time-asymptotic peculiar particle speed is largely non-relativistic also in the geodesic case.

  3. Rubber friction on smooth surfaces

    E-Print Network [OSTI]

    B. N. J. Persson; A. I. Volokitin

    2006-07-04T23:59:59.000Z

    We study the sliding friction for viscoelastic solids, e.g., rubber, on hard flat substrate surfaces. We consider first the fluctuating shear stress inside a viscoelastic solid which results from the thermal motion of the atoms or molecules in the solid. At the nanoscale the thermal fluctuations are very strong and give rise to stress fluctuations in the MPa-range, which is similar to the depinning stresses which typically occur at solid-rubber interfaces, indicating the crucial importance of thermal fluctuations for rubber friction on smooth surfaces. We develop a detailed model which takes into account the influence of thermal fluctuations on the depinning of small contact patches (stress domains) at the rubber-substrate interface. The theory predicts that the velocity dependence of the macroscopic shear stress has a bell-shaped f orm, and that the low-velocity side exhibits the same temperature dependence as the bulk viscoelastic modulus, in qualitative agreement with experimental data. Finally, we discuss the influence of small-amplitude substrate roughness on rubber sliding friction.

  4. Rubber friction on (apparently) smooth lubricated surfaces

    E-Print Network [OSTI]

    M. Mofidi; B. Prakash; B. N. J. Persson; O. Albohl

    2007-10-18T23:59:59.000Z

    We study rubber sliding friction on hard lubricated surfaces. We show that even if the hard surface appears smooth to the naked eye, it may exhibit short wavelength roughness, which may give the dominant contribution to rubber friction. That is, the observed sliding friction is mainly due to the viscoelastic deformations of the rubber by the substrate surface asperities. The presented results are of great importance for rubber sealing and other rubber applications involving (apparently) smooth surfaces.

  5. The three different regimes in coulombic friction

    E-Print Network [OSTI]

    Azzouz Dermoune; Daoud Ounaissi; Nadji Rahmania

    2015-04-24T23:59:59.000Z

    de Gennes identified three regimes in the phenomenon of the Langevin equation wich includes Coulombic friction. Here we extend and precise this phenomenon to a constant external force.

  6. Skin friction for steel piles in sand

    E-Print Network [OSTI]

    Sulaiman, Ibrahim Hikmat

    1967-01-01T23:59:59.000Z

    MOVEMENT 4) For dry pile tests at initial void ratio of 0. 63, the assumption of a Coulomb type failure applies and the envelope is shown in Figure 23. The skin friction computed is the total friction caused by applied load. and. the static load caused... Sand 43 22. Skin Friction-Chamber Pressure Ratio Versus Pile Movement for Dense Dry Sand 44 23 ~ 24. Mohr Envelope for Skin Friction Measured. and Assumed. Pile Deformation 49 25 ~ Computed and Actual Load-Movement Curves for Test Pile 1 26...

  7. Non-equilibrium Statistical Approach to Friction Models

    E-Print Network [OSTI]

    Shoichi Ichinose

    2015-05-18T23:59:59.000Z

    A geometric approach to the friction phenomena is presented. It is based on the holographic view which has recently been popular in the theoretical physics community. We see the system in one-dimension-higher space. The heat-producing phenomena are most widely treated by using the non-equilibrium statistical physics. We take 2 models of the earthquake. The dissipative systems are here formulated from the geometric standpoint. The statistical fluctuation is taken into account by using the (generalized) Feynman's path-integral.

  8. Process for treatment of residual gas

    SciTech Connect (OSTI)

    Nolden, K.

    1980-01-01T23:59:59.000Z

    A process is disclosed for the treatment of the residual gases which are produced when hydrogen sulfide is reduced, by combustion, to elementary sulfur by the Claus process. The residual gases are fed through a heated conduit and gas scrubber, wherein the temperature of those residual gases are maintained above the melting point of sulfur. A portion of the raw coke oven gas condensate is admitted to the gas scrubber to be returned to the coke oven battery main from the flushing liquid separator as flushing liquor. The residual gases are then conducted through the coke oven gas purification process equipment along with the raw coke oven gas where the residual gases are intermixed with the raw coke oven gas prior to tar separation.

  9. Some Hamiltonian Models of Friction

    E-Print Network [OSTI]

    Juerg Froehlich; Zhou Gang; Avy Soffer

    2010-11-15T23:59:59.000Z

    Mathematical results on some models describing the motion of a tracer particle through a Bose-Einstein condensate are described. In the limit of a very dense, very weakly interacting Bose gas and for a very large particle mass, the dynamics of the coupled system is determined by classical non-linear Hamiltonian equations of motion. The particle's motion exhibits deceleration corresponding to friction (with memory) caused by the emission of Cerenkov radiation of gapless modes into the gas. Precise results are stated and outlines of proofs are presented. Some technical details are deferred to forthcoming papers.

  10. EVALUATION OF A LOW FRICTION - HIGH EFFICIENCY ROLLER BEARING ENGINE

    SciTech Connect (OSTI)

    Kolarik, Robert V. II; Shattuck, Charles W.; Copper, Anthony P.

    2009-06-30T23:59:59.000Z

    This Low Friction (High Efficiency Roller Bearing) Engine (LFE) report presents the work done by The Timken Company to conduct a technology demonstration of the benefits of replacing hydrodynamic bearings with roller bearings in the crankshaft and camshaft assemblies of an internal combustion engine for the purpose of collecting data sufficient to prove merit. The engines in the present study have been more extensively converted to roller bearings than any previous studies (40 needle roller bearings per engine) to gain understanding of the full potential of application of bearing technology. The project plan called for comparative testing of a production vehicle which was already respected for having demonstrated low engine friction levels with a rollerized version of that engine. Testing was to include industry standard tests for friction, emissions and fuel efficiency conducted on instrumented dynamometers. Additional tests for fuel efficiency, cold start resistance and other measures of performance were to be made in the actual vehicle. Comparative measurements of noise, vibration and harshness (NVH), were planned, although any work to mitigate the suspected higher NVH level in the rollerized engine was beyond the scope of this project. Timken selected the Toyota Avalon with a 3.5L V-6 engine as the test vehicle. In an attempt to minimize cost and fabrication time, a ‘made-from’ approach was proposed in which as many parts as possible would be used or modified from production parts to create the rollerized engine. Timken commissioned its test partner, FEV Engine Technology, to do a feasibility study in which they confirmed that using such an approach was possible to meet the required dimensional restrictions and tolerances. In designing the roller bearing systems for the crank and cam trains, Timken utilized as many production engine parts as possible. The crankshafts were produced from production line forgings, which use Timken steel, modified with special machining and heat treatment. Timken designed and manufactured all of the roller bearing related components such as the thrust bearing package. The production connecting rods and camshafts could not be used for the roller bearing engine, so new ones were produced according to the team’s designs using Timken steel. The remaining miscellaneous components were designed and procured by FEV. Timken prepared a display version of the crankshaft portion of the production engine without connecting rods which could be driven by a motor through a cogged-belt and electrically actuated clutch arrangement. A modified version was also made in which the engine was outfitted with roller bearings on the main bearing positions. Preliminary tests showed that the rollerized engine was running with 1/3 less friction than the standard display engine. Additional friction testing and noise characterization was cut short because of shipping damage to the rollerized engine display and because of other project priorities. The team did successfully demonstrate the ability to package roller bearings satisfactorily in numerous locations in a typical automotive engine. The scope of this project did not include durability demonstration and that subject would have to be addressed in any follow-on work. In the actual test phase, the rollerized engine did show significantly less friction in motored dynamometer tests compared to its production equivalent. The 5-10% improvement measured in this study was about half that seen in other studies. However, the fired test results did not show a reduction in friction which did not match prior experience or expectations. Subsequent teardown and inspection of the rollerized engine revealed potential sources of excessive friction in the experimental application. These features would be eliminated in a design not based on modification of production parts. The team is confident (based on experience) that friction reduction would be realized with proper modifications.

  11. Stress Wave Source Characterization: Impact, Fracture, and Sliding Friction

    E-Print Network [OSTI]

    McLaskey, Gregory Christofer

    2011-01-01T23:59:59.000Z

    tremor like signals in friction experiments, Geophys. Res.analysis of the state- and rate-dependent friction law:Static friction, Physical Rev. B 59, 14313-14327. Bisschop,

  12. Friction Coefficient for Quarks in Supergravity Duals

    E-Print Network [OSTI]

    E. Antonyan

    2006-11-22T23:59:59.000Z

    We study quarks moving in strongly-coupled plasmas that have supergravity duals. We compute the friction coefficient of strings dual to such quarks for general static supergravity backgrounds near the horizon. Our results also show that a previous conjecture on the bound has to be modified and higher friction coefficients can be achieved.

  13. Friction Stir Spot Welding of Advanced High Strength Steels ...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    does not contain any proprietary or confidential information Friction Stir Spot Welding of Advanced High Strength Steels (AHSS) (13056 ORNL, 13055 PNNL) Friction Stir Spot...

  14. Efficiency Improvement through Reduction in Friction and Wear...

    Energy Savers [EERE]

    More Documents & Publications Heavy Truck Friction & Wear Reduction Technologies Development of High Power Density Driveline for Vehicles Low-Friction Engineered Surfaces...

  15. Friction forces on phase transition fronts

    E-Print Network [OSTI]

    Ariel Megevand

    2013-03-31T23:59:59.000Z

    In cosmological first-order phase transitions, the microscopic interaction of the phase transition fronts with non-equilibrium plasma particles manifests itself macroscopically as friction forces. In general, it is a nontrivial problem to compute these forces, and only two limits have been studied, namely, that of very slow walls and, more recently, ultra-relativistic walls which run away. In this paper we consider ultra-relativistic velocities and show that stationary solutions still exist when the parameters allow the existence of runaway walls. Hence, we discuss the necessary and sufficient conditions for the fronts to actually run away. We also propose a phenomenological model for the friction, which interpolates between the non-relativistic and ultra-relativistic values. Thus, the friction depends on two friction coefficients which can be calculated for specific models. We then study the velocity of phase transition fronts as a function of the friction parameters, the thermodynamic parameters, and the amount of supercooling.

  16. Dynamical Friction on extended perturbers

    E-Print Network [OSTI]

    O. Esquivel; B. Fuchs

    2008-04-01T23:59:59.000Z

    Following a wave-mechanical treatment we calculate the drag force exerted by an infinite homogeneous background of stars on a perturber as this makes its way through the system. We recover Chandrasekhar's classical dynamical friction (DF) law with a modified Coulomb logarithm. We take into account a range of models that encompasses all plausible density distributions for satellite galaxies by considering the DF exerted on a Plummer sphere and a perturber having a Hernquist profile. It is shown that the shape of the perturber affects only the exact form of the Coulomb logarithm. The latter converges on small scales, because encounters of the test and field stars with impact parameters less than the size of the massive perturber become inefficient. We confirm this way earlier results based on the impulse approximation of small angle scatterings.

  17. A numerical treatment of steady, frictional boundary currents in a homogeneous ocean applied to a semi-enclosed basin

    E-Print Network [OSTI]

    Jacobs, Clifford Albert

    1967-01-01T23:59:59.000Z

    characterizing the models Page 27 Effects of pararnetcrs o" and y on reduction rate of residuals for the bottona-friction model 55 Effects of parameters o and y or reduction rate of res iduals for the lateral-friction naodcl 58 IV. Effects of parameters v.... E I Variable parameters characterizing the models Par a!net e r Description Order ? of-Magnitude Estimate Units the length ot a grid square the coefficient of botto!rI frictior the horizortal-cdd y vis cos ity 10 6 -6 10 C 111 ? 1 sec...

  18. Friction Problems in Servomechanisms: Modeling and Compensation Techniques

    E-Print Network [OSTI]

    Gravdahl, Jan Tommy

    Friction Problems in Servomechanisms: Modeling and Compensation Techniques Jan Tommy Gravdahl of this presentation Introduction Friction models 1. Static models 2. Models with time delay 3. Dynamic models Friction compensation 1. Non-model based compensation 2. Compensation based on static friction models 3

  19. Torsion Spring Oscillator with Dry Friction Eugene I. Butikov

    E-Print Network [OSTI]

    Butikov, Eugene

    by viscous and dry (Coulomb) friction are investigated analytically and with the help of computer simulations-state oscillations. 1. Introduction Mechanical vibration systems with combined viscous and dry (Coulomb) friction. Even the simplest dry friction model, the Coulomb friction, can explain the principal peculiarities

  20. On the velocity-strengthening behavior of dry friction

    E-Print Network [OSTI]

    Bar-Sinai, Yohai; Brener, Efim A; Bouchbinder, Eran

    2013-01-01T23:59:59.000Z

    The onset of frictional instabilities, e.g. earthquakes nucleation, is intimately related to velocity-weakening friction, in which the frictional resistance of interfaces decreases with increasing slip velocity. While this frictional response has been studied extensively, much less attention has been given to steady-state velocity-strengthening friction, in spite of its importance for various aspects of frictional phenomena such as the propagation speed of interfacial rupture fronts and the amount of stored energy released by them. In this note we suggest that a crossover from steady-state velocity-weakening friction at small slip velocities to steady-state velocity-strengthening friction at higher velocities might be a generic feature of dry friction. We further argue that while thermally activated rheology naturally gives rise to logarithmic steady-state velocity-strengthening friction, a crossover to stronger-than-logarithmic strengthening might take place at higher slip velocities, possibly accompanied by...

  1. Short-time Dynamics of Frictional Strength in Dry Friction O. Ben-David, G. Cohen and J. Fineberg

    E-Print Network [OSTI]

    Fineberg, Jay

    Short-time Dynamics of Frictional Strength in Dry Friction O. Ben-David, G. Cohen and J. Fineberg interface that separates two PMMA blocks in dry frictional contact. At applied shear forces significantly weakening 1. Introduction The short-time dynamics of dry friction are of fundamental interest in fields

  2. Short-time Dynamics of Frictional Strength in Dry Friction O. Ben-David and J. Fineberg

    E-Print Network [OSTI]

    Fineberg, Jay

    Short-time Dynamics of Frictional Strength in Dry Friction O. Ben-David and J. Fineberg The Racah that separates two PMMA blocks in dry frictional contact. At applied shear forces significantly below the static The short-time dynamics of dry friction are of fundamental interest in fields ranging from hard drive disk

  3. Abstract--Friction modeling is essential for joint dynamic identification and control. Joint friction is composed of a

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    inertial and friction parameters of a lot of prototypes and industrial robots [1]- [10]. The kinematic

  4. Postulated Mesoscale Quantum of Internal Friction Hysteresis

    E-Print Network [OSTI]

    Randall D. Peters

    2004-05-27T23:59:59.000Z

    Evidence is provided, from yet another experiment, for the existence of a mesoscale quantum of internal friction hysteresis, having the value of the electron rest energy divided by the fine structure constant.

  5. Quantum Cherenkov radiation and noncontact friction

    E-Print Network [OSTI]

    Golestanian, Ramin

    We present a number of arguments to demonstrate that a quantum analog of the Cherenkov effect occurs when two nondispersive half spaces are in relative motion. We show that they experience friction beyond a threshold ...

  6. Action of friction Frictional processes are not often considered in

    E-Print Network [OSTI]

    Plant, Robert

    spindown of a cyclonic vortex due to Ekman pumping. Baroclinic PV generation Figure 2 shows the baroclinic, gave a minimum mean­sea­level pressure of 949mb at midnight. However, with fluxes of momentum and heat to boundary layer potential vorticity (PV). Assuming that the surface­layer stress de­ cays linearly across

  7. Composite heat damage assessment

    SciTech Connect (OSTI)

    Janke, C.J.; Wachter, E.A. [Oak Ridge National Lab., TN (United States); Philpot, H.E. [Oak Ridge K-25 Site, TN (United States); Powell, G.L. [Oak Ridge Y-12 Plant, TN (United States)

    1993-12-31T23:59:59.000Z

    The effects of heat damage were determined on the residual mechanical, physical, and chemical properties of IM6/3501-6 laminates, and potential nondestructive techniques to detect and assess material heat damage were evaluated. About one thousand preconditioned specimens were exposed to elevated temperatures, then cooled to room temperature and tested in compression, flexure, interlaminar shear, shore-D hardness, weight loss, and change in thickness. Specimens experienced significant and irreversible reduction in their residual properties when exposed to temperatures exceeding the material upper service temperature of this material (350{degrees}F). The Diffuse Reflectance Infrared Fourier Transform and Laser-Pumped Fluorescence techniques were found to be capable of rapid, in-service, nondestructive detection and quantitation of heat damage in IM6/3501- 6. These techniques also have the potential applicability to detect and assess heat damage effects in other polymer matrix composites.

  8. Casimir Friction I: Friction of a vacuum on a spinning dielectric

    E-Print Network [OSTI]

    Yves Pomeau; David C. Roberts

    2008-04-09T23:59:59.000Z

    We introduce the concept of Casimir friction, i.e. friction due to quantum fluctuations. In this first article we describe the calculation of a constant torque, arising from the scattering of quantum fluctuations, on a dielectric rotating in an electromagnetic vacuum.

  9. Evolution of Frictional Behavior of Punchbowl Fault Gouges Sheared at Seismic Slip Rates and Mechanical and Hydraulic Properties of Nankai Trough Accretionary Prism Sediments Deformed at Different Loading Paths

    E-Print Network [OSTI]

    Kitajima, Hiroko

    2012-02-14T23:59:59.000Z

    of frictional heating, mechanical behavior, and microstructure evolution? by Hiroko Kitajima, Judith S. Chester, Frederick M. Chester, and Toshihiko Shimamoto, 2010. Journal of Geophysical Research, 115, B08408, doi:10.1029/2009JB0 07038, Copyright 2010...

  10. Enhancement of disoriented chiral condensate domains with friction

    E-Print Network [OSTI]

    A. K. Chaudhuri

    1999-04-08T23:59:59.000Z

    We investigate the effect of friction on domain formation in disoriented chiral condensate. Including a friction term, we solve the equation of motion of the linear sigma model fields, in the Hartree approximation. With boost-invariance and cylinderical symmetry, irrespective of friction, on average, we donot find any indication of domain like formation with quenched initial condition. However, with or without friction, some events can be found with large instabilities, indicating possible DCC domain formation in those events. With friction time scale during which instabilities grows increases. Correspondingly, with friction, it is possible to obtain large sized domains in some particular events.

  11. Modelling of friction stir welding

    E-Print Network [OSTI]

    Colegrove, Paul Andrew

    is influenced by the fractUling of the tungsten wire. Finally, Nowak et al. 85 examined the flow during the FSW of polycarbonate and found similar flow fields to those observed in aluminium. Because of polycarbonate's different properties it was necessary... is conducted into the tool and welded material, and is then convected from the top surface or conducted into the backing plate. Both analytical and numerical models have been used to describe this heat flow. The following section describes thermal modelling...

  12. Casimir Friction Force Between Polarizable Media

    E-Print Network [OSTI]

    Johan S. Høye; Iver Brevik

    2012-01-18T23:59:59.000Z

    This work is a continuation of our recent series of papers on Casimir friction, for a pair of particles of low relative particle velocity. Each particle is modeled as a simple harmonic oscillator. Our basic method, as before, is the use of quantum mechanical statistical mechanics, involving the Kubo formula, at finite temperature. In this work we begin by analyzing the Casimir friction between two particles polarizable in all spatial directions, this being a generalization of our study in EPL 91, 60003 (2010), which was restricted to a pair of particles with longitudinal polarization only. For simplicity the particles are taken to interact via the electrostatic dipole-dipole interaction. Thereafter, we consider the Casimir friction between one particle and a dielectric half-space, and also the friction between two dielectric half-spaces. Finally, we consider general polarizabilities (beyond the simple one-oscillator form), and show how friction occurs at finite temperature when finite frequency regions of the imaginary parts of polarizabilities overlap.

  13. Friction and dilatancy in immersed granular matter

    E-Print Network [OSTI]

    Thibaut Divoux; Jean-Christophe Géminard

    2008-06-10T23:59:59.000Z

    The friction of a sliding plate on a thin immersed granular layer obeys Amonton-Coulomb law. We bring to the fore a large set of experimental results which indicate that, over a few decades of values, the effective dynamical friction-coefficient depends neither on the viscosity of the interstitial fluid nor on the size of beads in the sheared layer, which bears out the analogy with the solid-solid friction in a wide range of experimental parameters. We accurately determine the granular-layer dilatancy, which dependance on the grain size and slider velocity can be qualitatively accounted by considering the rheological behaviour of the whole slurry. However, additional results, obtained after modification of the grain surface by a chemical treatment, demonstrate that the theoretical description of the flow properties of granular matter, even immersed, requires the detailed properties of the grain surface to be taken into account.

  14. Friction forces on atoms after acceleration

    E-Print Network [OSTI]

    Francesco Intravaia; Vanik E. Mkrtchian; Stefan Buhmann; Stefan Scheel; Diego A. R. Dalvit; Carsten Henkel

    2015-02-04T23:59:59.000Z

    The aim of this paper is to revisit the calculation of atom-surface quantum friction in the quantum field theory formulation put forward by Barton [New J. Phys. 12 (2010) 113045]. We show that the power dissipated into field excitations and the associated friction force depend on how the atom is boosted from being initially at rest to a configuration in which it is moving at constant velocity (v) parallel to the planar interface. In addition, we point out that there is a subtle cancellation between the one-photon and part of the two-photon dissipating power, resulting in a leading order contribution to the frictional power which goes as v^4. These results are also confirmed by an alternative calculation of the average radiation force, which scales as v^3.

  15. Dynamical friction in modified Newtonian dynamics

    E-Print Network [OSTI]

    C. Nipoti; L. Ciotti; J. Binney; P. Londrillo

    2008-03-31T23:59:59.000Z

    We have tested a previous analytical estimate of the dynamical friction timescale in Modified Newtonian Dynamics (MOND) with fully non-linear N-body simulations. The simulations confirm that the dynamical friction timescale is significantly shorter in MOND than in equivalent Newtonian systems, i.e. systems with the same phase-space distribution of baryons and additional dark matter. An apparent conflict between this result and the long timescales determined for bars to slow and mergers to be completed in previous N-body simulations of MOND systems is explained. The confirmation of the short dynamical-friction timescale in MOND underlines the challenge that the Fornax dwarf spheroidal poses to the viability of MOND.

  16. Method and device for frictional welding

    DOE Patents [OSTI]

    Peacock, H.B.

    1992-10-13T23:59:59.000Z

    A method is described for friction welding that produces a seal having essentially no gas porosity, comprises two rotationally symmetric, generally cylindrical members, spaced apart and coaxially aligned, that are rotated with respect to each other and brought together under high pressure. One member is preferably a generally cylindrical canister that stores uranium within its hollow walls. The other member is preferably a generally cylindrical, hollow weld ring. An annular channel formed in the weld ring functions as an internal flash trap and is uniquely designed so that substantially all of the welding flash generated from the friction welding is directed into the channel's recessed bottom. Also, the channel design limits distortion of the two members during the friction welding process, further contributing to the complete seal that is obtained. 5 figs.

  17. Method and device for frictional welding

    DOE Patents [OSTI]

    Peacock, Harold B. (867 N. Belair Rd., Evans, GA 30809)

    1992-01-01T23:59:59.000Z

    A method for friction welding that produces a seal having essentially no gas porosity, comprises two rotationally symmetric, generally cylindrical members, spaced apart and coaxially aligned, that are rotated with respect to each other and brought together under high pressure. One member is preferably a generally cylindrical cannister that stores uranium within its hollow walls. The other member is preferably a generally cylindrical, hollow weld ring. An annular channel formed in the weld ring functions as an internal flash trap and is uniquely designed so that substantially all of the welding flash generated from the friction welding is directed into the channel's recessed bottom. Also, the channel design limits distortion of the two members during the friction welding process, further contributing to the complete seal that is obtained.

  18. Method and device for frictional welding

    DOE Patents [OSTI]

    Peacock, H.B.

    1991-01-01T23:59:59.000Z

    A method for friction welding that produces a seal having essentially no gas porosity, comprises two rotationally symmetric, generally cylindrical members, spaced apart and coaxially aligned, that are rotated with respect to each other and brought together under high pressure. One member is preferably a generally cylindrical cannister that stores uranium within its hollow walls. The other member is preferably a generally cylindrical, hollow weld ring. An annular channel formed in the weld ring functions as an internal flash trap and is uniquely designed so that substantially all of the welding flash generated from the friction welding is directed into the channel`s recessed bottom. Also, the channel design limits distortion of the two members during the friction welding, process, further contributing to the complete seal that is obtained.

  19. High fidelity frictional models for MEMS.

    SciTech Connect (OSTI)

    Carpick, Robert W. (University of Wisconsin, Madison, WI); Reedy, Earl David, Jr.; Bitsie, Fernando; de Boer, Maarten Pieter; Corwin, Alex David; Ashurst, William Robert (Auburn University, Auburn, AL); Jones, Reese E.; Subhash, Ghatu S. (Michigan Technological Institute, Houghton, MI); Street, Mark D. (University of Wisconsin, Madison, WI); Sumali, Anton Hartono; Antoun, Bonnie R.; Starr, Michael James; Redmond, James Michael; Flater, Erin E. (University of Wisconsin, Madison, WI)

    2004-10-01T23:59:59.000Z

    The primary goals of the present study are to: (1) determine how and why MEMS-scale friction differs from friction on the macro-scale, and (2) to begin to develop a capability to perform finite element simulations of MEMS materials and components that accurately predicts response in the presence of adhesion and friction. Regarding the first goal, a newly developed nanotractor actuator was used to measure friction between molecular monolayer-coated, polysilicon surfaces. Amontons law does indeed apply over a wide range of forces. However, at low loads, which are of relevance to MEMS, there is an important adhesive contribution to the normal load that cannot be neglected. More importantly, we found that at short sliding distances, the concept of a coefficient of friction is not relevant; rather, one must invoke the notion of 'pre-sliding tangential deflections' (PSTD). Results of a simple 2-D model suggests that PSTD is a cascade of small-scale slips with a roughly constant number of contacts equilibrating the applied normal load. Regarding the second goal, an Adhesion Model and a Junction Model have been implemented in PRESTO, Sandia's transient dynamics, finite element code to enable asperity-level simulations. The Junction Model includes a tangential shear traction that opposes the relative tangential motion of contacting surfaces. An atomic force microscope (AFM)-based method was used to measure nano-scale, single asperity friction forces as a function of normal force. This data is used to determine Junction Model parameters. An illustrative simulation demonstrates the use of the Junction Model in conjunction with a mesh generated directly from an atomic force microscope (AFM) image to directly predict frictional response of a sliding asperity. Also with regards to the second goal, grid-level, homogenized models were studied. One would like to perform a finite element analysis of a MEMS component assuming nominally flat surfaces and to include the effect of roughness in such an analysis by using a homogenized contact and friction models. AFM measurements were made to determine statistical information on polysilicon surfaces with different roughnesses, and this data was used as input to a homogenized, multi-asperity contact model (the classical Greenwood and Williamson model). Extensions of the Greenwood and Williamson model are also discussed: one incorporates the effect of adhesion while the other modifies the theory so that it applies to the case of relatively few contacting asperities.

  20. Seismic Interstory Drift Demands in Steel Friction Damped Braced Buildings

    E-Print Network [OSTI]

    Peternell Altamira, Luis E.

    2010-01-16T23:59:59.000Z

    Figure 2.4: Sumitomo friction damper and installation detail (Aiken and Kelly 1990) .... 9 Figure 2.5: Slotted bolted connection of Fitzgerald (1989) and typical force- displacement loop... a superior performance of friction damped braced frames (FDBFs) using this device compared to traditional earthquake resisting systems. Figure 2.2: Friction Damper of Pall (1982) 8 In Japan, Sumitomo Metal Industries developed...

  1. Friction as an activated process Ondej Soucek, Frantisek Gallovic

    E-Print Network [OSTI]

    Cerveny, Vlastislav

    Friction as an activated process Ondej Soucek, Frantisek Gallovic Mathematical Institute University in Prague 30.11.2011 (Geodynamical seminar) Friction as an activated process 30.11.2011 1 / 19 #12 - non-smoothness of the "potentials" (Geodynamical seminar) Friction as an activated process 30

  2. ON THE IDENTIFICATION AND HAPTIC DISPLAY OF FRICTION

    E-Print Network [OSTI]

    Stanford University

    ON THE IDENTIFICATION AND HAPTIC DISPLAY OF FRICTION A DISSERTATION SUBMITTED TO THE DEPARTMENT by Christopher Richard All Rights Reserved #12;iv Abstract Although friction is an important phenomenon and greatly affects the way in which individ- uals interact with the world, friction is all but absent from

  3. Friction and the Inverted Pendulum Stabilization Problem Sue Ann Campbell

    E-Print Network [OSTI]

    Campbell, Sue Ann

    Friction and the Inverted Pendulum Stabilization Problem Sue Ann Campbell Department of Applied can move in one dimension. We study the effect of friction on the design and performance of a feedback that a controller designed using a simple viscous friction model has poor performance - small amplitude oscillations

  4. Friction and Adhesion Hysteresis between Surfactant Monolayers in Water

    E-Print Network [OSTI]

    Klein, Jacob

    Friction and Adhesion Hysteresis between Surfactant Monolayers in Water Wuge H. Briscoe Physical friction between two surfaces in adhesive contact with the loading­unloading adhesion hysteresis between them. We then examine in light of this model the observed low friction between two mica surfaces coated

  5. Friction-Induced Vibrations in Railway Transportation Chandra Prakash Sharma

    E-Print Network [OSTI]

    Phani, A. Srikantha

    Friction-Induced Vibrations in Railway Transportation by Chandra Prakash Sharma B. Tech., Sardar;Abstract Controlling friction at the wheel-rail interface is indispensable for extending track life implementation of friction modifier system consists of a stick-tube assembly, attached through a bracket which

  6. ORIGINAL PAPER Modeling of Thermal-Assisted Dislocation Friction

    E-Print Network [OSTI]

    Marks, Laurence D.

    ORIGINAL PAPER Modeling of Thermal-Assisted Dislocation Friction Y. Liao · L. D. Marks Received: 25+Business Media, LLC 2009 Abstract We generalize a model for friction at a sliding interface involving the motion of thermally activated friction. Going further, we suggest a plausible method for generalizing the fric- tional

  7. Analysis and Model-Based Control of Servomechanisms With Friction

    E-Print Network [OSTI]

    Papadopoulos, Evangelos

    Analysis and Model-Based Control of Servomechanisms With Friction Evangelos G. Papadopoulos e Engineering, National Technical University of Athens, 15780 Athens, Greece Friction is responsible for several, model-based feedback compensation is studied for servomechanism tracking tasks. Several kinetic friction

  8. Enhancing Physicality in Touch Interaction with Programmable Friction

    E-Print Network [OSTI]

    Levesque, Vincent

    Enhancing Physicality in Touch Interaction with Programmable Friction Vincent Lévesque1 , Louise possibilities and outcomes when touch interactions are enhanced with variable surface friction. In a series of four studies, we first confirm that variable friction gives significant performance advantages in low

  9. Friction versus dilation revisited: Insights from theoretical and numerical models

    E-Print Network [OSTI]

    Einat, Aharonov

    Friction versus dilation revisited: Insights from theoretical and numerical models N. Makedonska,1 controlled by the frictional strength of the fault gouge, a granular layer that accumulates between the fault friction coefficient) of such granular layers is the systems resistance to dilation, a byprocess

  10. Solid friction in gel electrophoresis S. F. Burlatskya)

    E-Print Network [OSTI]

    Deutch, John

    Solid friction in gel electrophoresis S. F. Burlatskya) and John M. Deutch Department of Chemistry 1995 We study the influence of solid frictional forces acting on polymer chains moving in a random environment. We show that the total reduction in the chain tension resulting from the small friction between

  11. Molecular friction and epitactic coupling between monolayers in supported bilayers

    E-Print Network [OSTI]

    Boyer, Edmond

    1535 Molecular friction and epitactic coupling between monolayers in supported bilayers R. Merkel un substrat de membrane couplée (Evans et Sackmann, 1988), on détermine la friction moléculaire coefficients de friction entre les couches en fixant la couche mononucléaire proximale sur le substrat par des

  12. Penetration rate prediction for percussive drilling via dry friction model

    E-Print Network [OSTI]

    Krivtsov, Anton M.

    Penetration rate prediction for percussive drilling via dry friction model Anton M. Krivtsov a of percussive drilling assuming a dry friction mechanism to explain the experimentally observed drop in pene as a frictional pair, and this can generate the pattern of the impact forces close to reality. Despite quite

  13. Dry friction avalanches: Experiment and theory Sergey V. Buldyrev,1

    E-Print Network [OSTI]

    Buldyrev, Sergey

    Dry friction avalanches: Experiment and theory Sergey V. Buldyrev,1 John Ferrante,2 and Fredy R and theoretical models are presented supporting the conjecture that dry friction stick-slip is described by self in systems presenting stick-slip due to dry friction has been under scrutiny 11 . Experimental evidence

  14. STUDIES OF THE DYNAMICS OF DRY-FRICTION-DAMPED BLADE

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    STUDIES OF THE DYNAMICS OF DRY-FRICTION-DAMPED BLADE ASSEMBLIES by J er^ome Guillen A dissertation . . . . . . . . . . . . . . . . . . . . . . . . . 17 2.3 Multi-DOF systems with a single friction damper . . . . . . . 20 2.3.1 System model with multiple friction dampers . . . . . . 31 2.5 Conclusion

  15. Friction Stir Welding John Hinch and John Rudge

    E-Print Network [OSTI]

    Rudge, John

    Friction Stir Welding John Hinch and John Rudge September 11, 2002 1 Introduction Friction Stir Welding is an innovative technique for joining two pieces of metal. A rapidly rotating tool is pushed that a good model of friction stir welding should be able to predict - the power, the force, the temperature

  16. ORIGINAL ARTICLE Frictional systems subjected to oscillating loads

    E-Print Network [OSTI]

    Barber, James R.

    ORIGINAL ARTICLE Frictional systems subjected to oscillating loads J. R. Barber Received: 3 and a generalized Hertzian contact problem with friction. Keywords Coulomb friction Á Shakedown Á Damping Á of appropriate interaction laws for use in the analysis of masonry structures [1] and for the discrete element

  17. A Simple Model on Granular Friction Hisao Hayakawa

    E-Print Network [OSTI]

    Hayakawa, Hisao

    observed even in atomic dry friction and and melt fractures in polymers [9,10]. Recently, Nasuno et al [11 for simulation of granular particles [13]. In particular, we 2 #12; regard Coulomb's friction law duringA Simple Model on Granular Friction Hisao Hayakawa Graduate School of Human and Environmental

  18. Torsion Spring Oscillator with Dry Friction Eugene Butikov

    E-Print Network [OSTI]

    Butikov, Eugene

    at investigation of free oscillations of a torsion spring pendulum damped by dry (Coulomb) friction. An idealizedTorsion Spring Oscillator with Dry Friction Manual Eugene Butikov Annotation. The manual includes as a prerequisite for the virtual lab "Torsion Spring Oscillator with Dry Friction." The manual includes also a set

  19. NUMERICAL APPROXIMATION OF P-SYSTEMS WITH COULOMB FRICTIONAL DAMPING

    E-Print Network [OSTI]

    to the precise nature of the dissipation. Dry (Coulomb) friction is a limit case that has not been fully analyzed in the presence of dry ­ Coulomb­ friction. A model is described in detail in Section 2. A discretizationNUMERICAL APPROXIMATION OF P-SYSTEMS WITH COULOMB FRICTIONAL DAMPING KRISTY COFFEY AND PIERRE A

  20. Heat transfer and pressure drop data for high heat flux densities to water at high subcritical pressures

    E-Print Network [OSTI]

    Rohsenow, Warren M.

    1951-01-01T23:59:59.000Z

    Local surface ooeffioients of heat t-ansfer, overall pressure drop data and mean friction factor are presented for heat flamms up to 3.52106 BtuAr ft2 for water flowing in a nickel tabe isder the following conditions: mass ...

  1. Casimir Friction Force for Moving Harmonic Oscillators

    E-Print Network [OSTI]

    Johan S. Høye; Iver Brevik

    2011-11-21T23:59:59.000Z

    Casimir friction is analyzed for a pair of dielectric particles in relative motion. We first adopt a microscopic model for harmonically oscillating particles at finite temperature T moving non-relativistically with constant velocity. We use a statistical-mechanical description where time-dependent correlations are involved. This description is physical and direct, and, in spite of its simplicity, is able to elucidate the essentials of the problem. This treatment elaborates upon, and extends, an earlier theory of ours back in 1992. The energy change Delta E turns out to be finite in general, corresponding to a finite friction force. In the limit of zero temperature the formalism yields, however, Delta E ->0, this being due to our assumption about constant velocity, meaning slowly varying coupling. For couplings varying more rapidly, there will also be a finite friction force at T=0. As second part of our work, we consider the friction problem using time-dependent perturbation theory. The dissipation, basically a second order effect, is obtainable with the use of first order theory, the reason being the absence of cross terms due to uncorrelated phases of eigenstates. The third part of the present paper is to demonstrate explicitly the equivalence of our results with those recently obtained by Barton (2010); this being not a trivial task since the formal results are seemingly quite different from each other.

  2. Flow boiling of water in a circular staggered micro-pin fin heat sink Santosh Krishnamurthy, Yoav Peles *

    E-Print Network [OSTI]

    Peles, Yoav

    across a bank of heated tube bundles, have shown that the local two-phase heat transfer coefficient across a tube bundle and determined the void fraction, the frictional pressure drop, and the local heatFlow boiling of water in a circular staggered micro-pin fin heat sink Santosh Krishnamurthy, Yoav

  3. Shear Jamming in Granular Experiments without Basal Friction

    E-Print Network [OSTI]

    Hu Zheng; Joshua A. Dijksman; Robert P. Behringer

    2014-08-08T23:59:59.000Z

    Jammed states of frictional granular systems can be induced by shear strain at densities below the isostatic jamming density ($\\phi_c$). It remains unclear, however, how much friction affects this so-called shear-jamming. Friction appears in two ways in this type of experiment: friction between particles, and friction between particles and the base on which they rest. Here, we study how particle-bottom friction, or basal friction, affects shear jamming in quasi-two dimensional experiments. In order to study this issue experimentally, we apply simple shear to a disordered packing of photoelastic disks. We can tune the basal friction of the particles by immersing the particles in a density matched liquid, thus removing the normal force, hence the friction, between the particles and base. We record the overall shear stress, and particle motion, and the photoelastic response of the particles. We compare the shear response of dry and immersed samples, which enables us to determine how basal friction affects shear jamming. Our findings indicate that changing the basal friction shifts the point of shear jamming, but it does not change the basic phenomenon of shear jamming.

  4. Dynamical friction in constant density cores: a failure of the Chandrasekhar formula

    E-Print Network [OSTI]

    J. I. Read; Tobias Goerdt; Ben Moore; A. P. Pontzen; Joachim Stadel; George Lake

    2006-10-04T23:59:59.000Z

    Using analytic calculations and N-body simulations we show that in constant density (harmonic) cores, sinking satellites undergo an initial phase of very rapid (super-Chandrasekhar) dynamical friction, after which they experience no dynamical friction at all. For density profiles with a central power law profile of log-slope, $-\\alpha$, the infalling satellite heats the background and causes $\\alpha$ to decrease. For $\\alpha < 0.5$ initially, the satellite generates a small central constant density core and stalls as in the $\\alpha = 0$ case. We discuss some astrophysical applications of our results to decaying satellite orbits, galactic bars and mergers of supermassive black hole binaries. In a companion paper we show that a central constant density core can provide a natural solution to the timing problem for Fornax's globular clusters.

  5. Friction Reduction for Microhole CT Drilling

    SciTech Connect (OSTI)

    Ken Newman; Patrick Kelleher; Edward Smalley

    2007-03-31T23:59:59.000Z

    The objective of this 24 month project focused on improving microhole coiled tubing drilling bottom hole assembly (BHA) reliability and performance, while reducing the drilling cost and complexity associated with inclined/horizontal well sections. This was to be accomplished by eliminating the need for a downhole drilling tractor or other downhole coiled tubing (CT) friction mitigation techniques when drilling long (>2,000 ft.) of inclined/horizontal wellbore. The technical solution to be developed and evaluated in this project was based on vibrating the coiled tubing at surface to reduce the friction along the length of the downhole CT drillstring. The Phase 1 objective of this project centered on determining the optimum surface-applied vibration system design for downhole CT friction mitigation. Design of the system would be based on numerical modeling and laboratory testing of the CT friction mitigation achieved with various types of surface-applied vibration. A numerical model was developed to predict how far downhole the surface-applied vibration would travel. A vibration test fixture, simulating microhole CT drilling in a horizontal wellbore, was constructed and used to refine and validate the numerical model. Numerous tests, with varying surface-applied vibration parameters were evaluated in the vibration test fixture. The data indicated that as long as the axial force on the CT was less than the helical buckling load, axial vibration of the CT was effective at mitigating friction. However, surface-applied vibration only provided a small amount of friction mitigation as the helical buckling load on the CT was reached or exceeded. Since it would be impractical to assume that routine field operations be conducted at less than the helical buckling load of the CT, it was determined that this technical approach did not warrant the additional cost and maintenance issues that would be associated with the surface vibration equipment. As such, the project was concluded following completion of Phase 1, and Phase 2 (design, fabrication, and testing of a prototype surface vibration system) was not pursued.

  6. Control of friction at the nanoscale

    DOE Patents [OSTI]

    Barhen, Jacob; Braiman, Yehuda Y.; Protopopescu, Vladimir

    2010-04-06T23:59:59.000Z

    Methods and apparatus are described for control of friction at the nanoscale. A method of controlling frictional dynamics of a plurality of particles using non-Lipschitzian control includes determining an attribute of the plurality of particles; calculating an attribute deviation by subtracting the attribute of the plurality of particles from a target attribute; calculating a non-Lipschitzian feedback control term by raising the attribute deviation to a fractionary power .xi.=(2m+1)/(2n+1) where n=1, 2, 3 . . . and m=0, 1, 2, 3 . . . , with m strictly less than n and then multiplying by a control amplitude; and imposing the non-Lipschitzian feedback control term globally on each of the plurality of particles; imposing causes a subsequent magnitude of the attribute deviation to be reduced.

  7. Dynamics of Dry Friction: A Numerical Investigation

    E-Print Network [OSTI]

    Y. F. Lim; Kan Chen

    1998-03-18T23:59:59.000Z

    We perform extended numerical simulation of the dynamics of dry friction, based on a model derived from the phenomenological description proposed by T. Baumberger et al.. In the case of small deviation from the steady sliding motion, the model is shown to be equivalent to the state- and rate-dependent friction law which was first introduced by Rice and Ruina on the basis of experiments on rocks. We obtain the dynamical phase diagram that agrees well with the experimental results on the paper-on-paper systems. In particular, the bifurcation between stick-slip and steady sliding are shown to change from a direct (supercritical) Hopf type to an inverted (subcritical) one as the driving velocity increases, in agreement with the experiments.

  8. Neutron scattering residual stress measurements on gray cast iron brake discs

    SciTech Connect (OSTI)

    Spooner, S.; Payzant, E.A.; Hubbard, C.R. [and others

    1996-11-01T23:59:59.000Z

    Neutron diffraction was used to investigate the effects of a heat treatment designed to remove internal residual stresses in brake discs. It is believed that residual stresses may change the rate of deformation of the discs during severe braking conditions when the disc temperature is increased significantly. Neutron diffraction was used to map out residual strain distributions in a production disc before and after a stress-relieving heat treatment. Results from these neutron diffraction experiments show that some residual strains were reduced by as much as 400 microstrain by stress relieving. 5 refs., 5 figs., 1 tab.

  9. The Effect of the Treatment of Localised Friction in Two-Phase Mixtures on the Stability of Parallel Channels

    SciTech Connect (OSTI)

    Abdou, H.N.; Garea, V.B. [Instituto Balseiro and Centro Atomico Bariloche, CNEA, Av. Bustillo 9500, Bariloche, RN 8400 (Argentina); Larreteguy, A.E. [Universidad Argentina de la Empresa, Lima 717, 1073 Buenos Aires (Argentina)

    2002-07-01T23:59:59.000Z

    A one-dimensional analytical model has been developed to be used for the linear analysis of density-wave oscillations in a parallel heated channel. The heated channel is divided into a single-phase and a two-phase region. The two-phase region is represented by the homogeneous model. The localised friction at the channel exit is treated considering the two-phase mixture. The exact equation for the total channel pressure drop is perturbed around the steady state. The stability characteristics of the heated channel are investigated using the Nyquist criterion. The marginal stability boundary (MSB) is determined in the two-dimensional thermodynamic equilibrium space parameters, the subcooled boiling number and the phase change number. The predictions of the model are compared with experimental results published in open literature. The results indicate a more stable system with (1) low system pressure, (2) high inlet restriction, (3) low outlet restriction, and (4) high inlet velocity. The results show that the model agrees well with the available experimental data. In particular, the results show the significance of correcting the localised friction due to the presence of the two-phase mixture in the two-phase region: explicit inclusion of the two-phase localised friction improves the agreement with experimental results. This effect is more important for high heating power and high inlet subcooling. (authors)

  10. No quantum friction between uniformly moving plates

    E-Print Network [OSTI]

    T. G. Philbin; U. Leonhardt

    2009-03-26T23:59:59.000Z

    The Casimir forces between two plates moving parallel to each other are found by calculating the vacuum electromagnetic stress tensor. The perpendicular force between the plates is modified by the motion but there is no lateral force on the plates. Electromagnetic vacuum fluctuations do not therefore give rise to "quantum friction" in this case, contrary to previous assertions. The result shows that the Casimir-Polder force on a particle moving at constant speed parallel to a plate also has no lateral component.

  11. Low-energy muons via frictional cooling

    E-Print Network [OSTI]

    Yu Bao; Allen Caldwell; Daniel Greenwald; Guoxing Xia

    2010-01-18T23:59:59.000Z

    Low-energy muon beams are useful for a range of physics experiments. We consider the production of low-energy muon beams with small energy spreads using frictional cooling. As the input beam, we take a surface muon source such as that at the Paul Scherrer Institute. Simulations show that the efficiency of low energy muon production can potentially be raised to 1%, which is significantly higher than that of current schemes.

  12. Frictional cooling of positively charged particles

    E-Print Network [OSTI]

    Daniel Greenwald; Allen Caldwell

    2011-11-14T23:59:59.000Z

    One of the focuses of research and development towards the construction of a muon collider is muon beam preparation. Simulation of frictional cooling shows that it can achieve the desired emittance reduction to produce high-luminosity muon beams. We show that for positively charged particles, charge exchange interactions necessitate significant changes to schemes previously developed for negatively charged particles. We also demonstrate that foil-based schemes are not viable for positive particles.

  13. The effect of friction on drum brakes

    SciTech Connect (OSTI)

    Huang, Y.M.; Shyr, J.S. [National Taiwan Univ. (China)

    1995-12-31T23:59:59.000Z

    The boundary element method (BEM) has been developed for a long period of time. Cruse and Wilson developed an isoparametric quadratic element. Rizzo, Cruse, Rizzo and Shippy, and Swedlow and cruse applied the method to various problems. It shows that the BEM can provide a very good analytical result in the linear problem and it can reduce time in preparation of numerical data. Watson and Newcomb pointed out that the pressure distribution on the contact surface of the brake drum and the lining plate do not vary significantly along the axis. The deflection can be reduced by an appropriate design of the web; therefore, two dimensional analysis with the BEM is used in this analysis. Based on the authors` knowledge, this is the first paper to analyze the drum brake by using the BEM. The assumptions are the brake drum to be a rigid body, perfect interface contact between the drum and the shoe, the constant friction coefficient of the friction material and the thermal effect to be neglected. The two dimensional equations are derived based on the Somigliana`s identity. Since there is no shape function and no need of the Jacobin for the coordinate transform, to integrate numerically is easier and to write a computer code is simpler for the constant value element than the second order element. The linear element is inappropriate to treat the comer problem. Using the linear elements or second order elements creates discontinuous phenomena along the irregular boundary. The common nodal point has different normal vector and boundary conditions. It is necessary to have an extra equation to provide a unique solution for the final linear equation. Using the constant value element can get rid of this problem. The effect of the friction on the pressure distribution at the friction interface is studied. The calculated results of the pressure distribution are compared with the available data. The mathematical model can be used as a design tool to predict the performance of drum brakes.

  14. Friction- and wear-reducing coating

    DOE Patents [OSTI]

    Zhu, Dong (Farmington Hills, MI); Milner, Robert (Warren, MI); Elmoursi, Alaa AbdelAzim (Troy, MI)

    2011-10-18T23:59:59.000Z

    A coating includes a first layer of a ceramic alloy and a second layer disposed on the first layer and including carbon. The coating has a hardness of from 10 to 20 GPa and a coefficient of friction of less than or equal to 0.12. A method of coating a substrate includes cleaning the substrate, forming the first layer on the substrate, and depositing the second layer onto the first layer to thereby coat the substrate.

  15. On the velocity-strengthening behavior of dry friction

    E-Print Network [OSTI]

    Yohai Bar-Sinai; Robert Spatschek; Efim A. Brener; Eran Bouchbinder

    2014-04-15T23:59:59.000Z

    The onset of frictional instabilities, e.g. earthquakes nucleation, is intimately related to velocity-weakening friction, in which the frictional resistance of interfaces decreases with increasing slip velocity. While this frictional response has been studied extensively, less attention has been given to steady-state velocity-strengthening friction, in spite of its potential importance for various aspects of frictional phenomena such as the propagation speed of interfacial rupture fronts and the amount of stored energy released by them. In this note we suggest that a crossover from steady-state velocity-weakening friction at small slip velocities to steady-state velocity-strengthening friction at higher velocities might be a generic feature of dry friction. We further argue that while thermally activated rheology naturally gives rise to logarithmic steady-state velocity-strengthening friction, a crossover to stronger-than-logarithmic strengthening might take place at higher slip velocities, possibly accompanied by a change in the dominant dissipation mechanism. We sketch a few physical mechanisms that may account for the crossover to stronger-than-logarithmic steady-state velocity-strengthening and compile a rather extensive set of experimental data available in the literature, lending support to these ideas.

  16. Mutual Friction in Superfluid Neutron Stars

    E-Print Network [OSTI]

    N. Andersson; T. Sidery; G. L. Comer

    2005-10-03T23:59:59.000Z

    We discuss vortex-mediated mutual friction in the two-fluid model for superfluid neutron star cores. Our discussion is based on the general formalism developed by Carter and collaborators, which makes due distinction between transport velocity and momentum for each fluid. This is essential for an implementation of the so-called entrainment effect, whereby the flow of one fluid imparts momentum in the other and vice versa. The mutual friction follows by balancing the Magnus force that acts on the quantised neutron vortices with a resistive force due to the scattering of electrons off of the magnetic field with which each vortex core is endowed. We derive the form of the macroscopic mutual friction force which is relevant for a model based on smooth-averaging over a collection of vortices. We discuss the coefficients that enter the expression for this force, and the timescale on which the two interpenetrating fluids in a neutron star core are coupled. This discussion confirms that our new formulation accords well with previous work in this area.

  17. Velocity tuning of friction with two trapped atoms

    E-Print Network [OSTI]

    Gangloff, Dorian; Counts, Ian; Jhe, Wonho; Vuleti?, Vladan

    2015-01-01T23:59:59.000Z

    Friction is the basic, ubiquitous mechanical interaction between two surfaces that results in resistance to motion and energy dissipation. In spite of its technological and economic significance, our ability to control friction remains modest, and our understanding of the microscopic processes incomplete. At the atomic scale, mismatch between the two contacting crystal lattices can lead to a reduction of stick-slip friction (structural lubricity), while thermally activated atomic motion can give rise to a complex velocity dependence, and nearly vanishing friction at sufficiently low velocities (thermal lubricity). Atomic force microscopy has provided a wealth of experimental results, but limitations in the dynamic range, time resolution, and control at the single-atom level have hampered a full quantitative description from first principles. Here, using an ion-crystal friction emulator with single-atom, single substrate-site spatial resolution and single-slip temporal resolution, we measure the friction force...

  18. Fact or friction: Inferring rheology from nonvolcanic tremor and low-frequency earthquakes on the deep San Andreas fault

    E-Print Network [OSTI]

    Thomas, Amanda

    2012-01-01T23:59:59.000Z

    2.5 Optimal friction coefficient . . . . . . . . . . . . . .effective coefficient of friction. Values for the tremor,procedure on each friction value for each catalogue. Maximum

  19. Effective friction law for smallscale fault heterogeneity in 3D dynamic rupture

    E-Print Network [OSTI]

    Nicolas, Chamot-Rooke

    Effective friction law for smallscale fault heterogeneity in 3D dynamic rupture S. Latour,1 M friction, we numerically construct effective friction laws that integrate the effects of smallscale, the static friction heterogeneities and the friction law. We first define a periodic smallscale heterogeneous

  20. Tool Durability Maps for Friction Stir Welding of an Aluminum Alloy T. DebRoy, A. De*, H.K.D.H. Bhadeshia**, V. D. Manvatkar*, A. Arora

    E-Print Network [OSTI]

    Cambridge, University of

    1 Tool Durability Maps for Friction Stir Welding of an Aluminum Alloy T. DebRoy, A. De*, H of premature tool failure. A scheme is created which exploits the physical three-dimensional heat and mass flow accumulation models, enables the plotting of tool durability maps which define the domains of satisfactory tool

  1. Micro- and macroscale coefficients of friction of cementitious materials

    SciTech Connect (OSTI)

    Lomboy, Gilson [Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, IA 50011 (United States)] [Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, IA 50011 (United States); Sundararajan, Sriram, E-mail: srirams@iastate.edu [Department of Mechanical Engineering, Iowa State University, Ames, IA 50011 (United States)] [Department of Mechanical Engineering, Iowa State University, Ames, IA 50011 (United States); Wang, Kejin [Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, IA 50011 (United States)] [Department of Civil, Construction, and Environmental Engineering, Iowa State University, Ames, IA 50011 (United States)

    2013-12-15T23:59:59.000Z

    Millions of metric tons of cementitious materials are produced, transported and used in construction each year. The ease or difficulty of handling cementitious materials is greatly influenced by the material friction properties. In the present study, the coefficients of friction of cementitious materials were measured at the microscale and macroscale. The materials tested were commercially-available Portland cement, Class C fly ash, and ground granulated blast furnace slag. At the microscale, the coefficient of friction was determined from the interaction forces between cementitious particles using an Atomic Force Microscope. At the macroscale, the coefficient of friction was determined from stresses on bulk cementitious materials under direct shear. The study indicated that the microscale coefficient of friction ranged from 0.020 to 0.059, and the macroscale coefficient of friction ranged from 0.56 to 0.75. The fly ash studied had the highest microscale coefficient of friction and the lowest macroscale coefficient of friction. -- Highlights: •Microscale (interparticle) coefficient of friction (COF) was determined with AFM. •Macroscale (bulk) COF was measured under direct shear. •Fly ash had the highest microscale COF and the lowest macroscale COF. •Portland cement against GGBFS had the lowest microscale COF. •Portland cement against Portland cement had the highest macroscale COF.

  2. Friction of different monolayer lubricants in MEMs interfaces.

    SciTech Connect (OSTI)

    Carpick, Robert W. (University of Wisconsin, Madison, WI); Street, Mark D. (University of Wisconsin, Madison, WI); Ashurst, William Robert (Auburn University, Auburn, AL); Corwin, Alex David

    2006-01-01T23:59:59.000Z

    This report details results from our last year of work (FY2005) on friction in MEMS as funded by the Campaign 6 program for the Microscale Friction project. We have applied different monolayers to a sensitive MEMS friction tester called the nanotractor. The nanotractor is also a useful actuator that can travel {+-}100 {micro}m in 40 nm steps, and is being considered for several MEMS applications. With this tester, we can find static and dynamic coefficients of friction. We can also quantify deviations from Amontons' and Coulomb's friction laws. Because of the huge surface-to-volume ratio at the microscale, surface properties such as adhesion and friction can dominate device performance, and therefore such deviations are important to quantify and understand. We find that static and dynamic friction depend on the monolayer lubricant applied. The friction data can be modeled with a non-zero adhesion force, which represents a deviation from Amontons' Law. Further, we show preliminary data indicating that the adhesion force depends not only on the monolayer, but also on the normal load applied. Finally, we also observe slip deflections before the transition from static to dynamic friction, and find that they depend on the monolayer.

  3. Friction Modeling for Lubricated Engine and Drivetrain Components...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Modeling for Lubricated Engine and Drivetrain Components Friction Modeling for Lubricated Engine and Drivetrain Components 2010 DOE Vehicle Technologies and Hydrogen Programs...

  4. Vehicle Technologies Office Merit Review 2015: Engine Friction Reduction Technologies

    Broader source: Energy.gov [DOE]

    Presentation given by Argonne National Laboratory at 2015 DOE Hydrogen and Fuel Cells Program and vehicle technologies office annual merit review and peer evaluation meeting about engine friction...

  5. Friction Stir Spot Welding of Advanced High Strength Steels II...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Steels II Friction Stir Spot Welding of Advanced High Strength Steels II 2011 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer...

  6. Vehicle Technologies Office Merit Review 2014: Engine Friction Reduction Technologies

    Broader source: Energy.gov [DOE]

    Presentation given by Argonne National Laboratory at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about engine friction...

  7. The influence of internal friction on rotordynamic instability

    E-Print Network [OSTI]

    Srinivasan, Anand

    2004-09-30T23:59:59.000Z

    and suggest that subsynchronous vibration in rotating machinery can have numerous sources or causes. Also, subsynchronous whirl due to internal friction is not a highly repeatable phenomenon....

  8. Friction of Steel Sliding Under Boundary Lubrication Regime in...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    by reducing parasitic boundary regime friction losses and enable operation with lower viscosity oils while maintaining engine durability. deer08erck.pdf More Documents &...

  9. Turbulent heat transfer in a trapezoidal channel with transverse and v-shaped ribs on two opposite walls

    E-Print Network [OSTI]

    Subramanian, Karthik

    2006-04-12T23:59:59.000Z

    This study investigates the turbulent heat transfer and friction in a trapezoidal channel with opposite walls roughened with transverse and v-shaped ribs. The roughened channel depicts the internal cooling passage of an aerofoil near the trailing...

  10. Turbulent heat transfer in a trapezoidal channel with transverse and v-shaped ribs on two opposite walls 

    E-Print Network [OSTI]

    Subramanian, Karthik

    2006-04-12T23:59:59.000Z

    This study investigates the turbulent heat transfer and friction in a trapezoidal channel with opposite walls roughened with transverse and v-shaped ribs. The roughened channel depicts the internal cooling passage of an ...

  11. Casimir friction: Relative motion more generally

    E-Print Network [OSTI]

    Johan S. Høye; Iver Brevik

    2014-09-23T23:59:59.000Z

    This paper extends our recent study on Casimir friction forces for dielectric plates moving parallel to each other [J. S. H{\\o}ye and I. Brevik, Eur. Phys. J. D {\\bf 68}, 61 (2014)], to the case where the plates are no longer restricted to rectilinear motion. Part of the mathematical formalism thereby becomes more cumbersome, but reduces in the end to the form that we could expect to be the natural one in advance. As an example, we calculate the Casimir torque on a planar disc rotating with constant angular velocity around its vertical symmetry axis next to another plate.

  12. Friction in a Model of Hamiltonian Dynamics

    E-Print Network [OSTI]

    Juerg Froehlich; Zhou Gang; Avy Soffer

    2011-11-01T23:59:59.000Z

    We study the motion of a heavy tracer particle weakly coupled to a dense ideal Bose gas exhibiting Bose-Einstein condensation. In the so-called mean-field limit, the dynamics of this system approaches one determined by nonlinear Hamiltonian evolution equations describing a process of emission of Cerenkov radiation of sound waves into the Bose-Einstein condensate along the particle's trajectory. The emission of Cerenkov radiation results in a friction force with memory acting on the tracer particle and causing it to decelerate until it comes to rest.

  13. Mesoscale Friction Anisotropy Revealed by Slidingless Tests

    SciTech Connect (OSTI)

    Annett, James [Trinity College; Gao, Yanfei [ORNL; Cross, Graham [Trinity College; Lucas, Barry N. [Fast Forward Devices, LLC.; Herbert, Erik G. [University of Tennessee, Knoxville (UTK)

    2011-01-01T23:59:59.000Z

    Using a recently developed multidimensional nanocontact system designed for a quantitative measurement of lateral contact stiffness in the 10-10{sup 6} N/m stiffness range (or 10-1000 nm contact size), we found a crystallographic-orientation-dependent lateral-stiffness reduction relative to the elastic prediction at contact sizes around 50 nm for polished Ni single crystal surface in air. The slidingless measurement is enabled by a frequency-specific, continuous stiffness measurement technique. Based on an interface microslip model and an anisotropic elastic contact analysis, the resulting friction stress is found to increase monotonically when the tested lateral direction rotates away from the closely packed direction.

  14. Abstract--Usually, the joint transmission friction model for robots is composed of a viscous friction force and of a constant

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    friction force and of a constant dry sliding friction force. However, according to the Coulomb law, the dry dynamic identification model for n degrees of freedom (dof) serial robot, where the dry sliding friction [1]-[10]. An approximation of the kinematic Coulomb friction, ( )CF sign q , is widely used to model

  15. Weak formulations and solution multiplicity of equilibrium configurations with Coulomb friction

    E-Print Network [OSTI]

    Bostan, Mihai

    Weak formulations and solution multiplicity of equilibrium configurations with Coulomb friction configurations of elastic struc- tures in contact with Coulomb friction. We obtain a variational formulation configurations with arbitrary small friction coefficients. We illustrate the result in two space dimensions

  16. Lubricant-Friendly, Superhard and Low-Friction Coatings by Design...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Lubricant-Friendly, Superhard and Low-Friction Coatings by Design Lubricant-Friendly, Superhard and Low-Friction Coatings by Design Superhard and low-friction coatings and surface...

  17. FRICTION AND WEAR STUDY OF DISPERSED PHASE INTERMETALLIC COMPOUNDS IN FERROUS MATRICES

    E-Print Network [OSTI]

    Riddle, R.A.

    2010-01-01T23:59:59.000Z

    rights. .j . J LBL-5771 FRICTION AND WEAR STUDY OF DISPERSEDS. THESIS) i LBL-5771 FRICTION AND WEAR STUDY OF DISPERSEDWilman, "A Theory of Friction and Wear During the Abrasion

  18. A Polynomial Chaos Approach to the Robust Analysis of the Dynamic Behaviour of Friction Systems

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    . Key word: Dry friction systems, Nonlinear dynamic systems, stability, limit cycle, robustness, uncertainty propagation, polynomial chaos, Lyapunov function, SOS programming. 1. Introduction Dry friction1 A Polynomial Chaos Approach to the Robust Analysis of the Dynamic Behaviour of Friction Systems

  19. Friction coefficients of sorghum grain on steel, teflon, and concrete surfaces

    E-Print Network [OSTI]

    Hossain, Quazi A

    1967-01-01T23:59:59.000Z

    termed "Coulomb friction" or dry friction. Merriam (26) differentiated it from "fluid friction" (that which occurs in the presence of a separating layer of lubricating fluid) and "internal friction" (that which resists e~ternal shear in a cohesionless... by many investigators, notably by de la Hire (17) and Euler (13) . The latter agreed with Amontons in giving to all surfaces a frictional coefficient of one third. The most systematic work on friction was done by Coulomb (12) . He examined a large...

  20. Quantized friction force: Lindbladian model satisfying Ehrenfest theorems

    E-Print Network [OSTI]

    Denys I. Bondar; Renan Cabrera; Andre Campos; Herschel A. Rabitz

    2014-12-05T23:59:59.000Z

    We construct a quantum counterpart of classical friction, a dissipative force acting against the direction of motion with the magnitude proportional to particle's velocity. In particular, a Lindblad master equation is derived satisfying the appropriate dynamical relations for observables (i.e., the Ehrenfest theorems). These findings significantly advance a long search for a universal valid Lindbladian model of quantum friction.

  1. METHODS PAPER Addressing Practical Challenges of Low Friction Coefficient

    E-Print Network [OSTI]

    Sawyer, Wallace

    sensitive to the lubrication, environment, and contact conditions, and under nominally constant conditions Tribol Trans ASME 127:673­678, 2005), ``...the measurement of friction coefficient is extremely sensitive, friction coefficients range from about 0.2 to 1 for typical material pairs under standard conditions

  2. The nonlinear nature of friction Michael Urbakh1

    E-Print Network [OSTI]

    La Rosa, Andres H.

    ) and GPa (104 atmospheres) within microseconds. These are extreme conditions that cannot always be treated ........................................................................................................................................................................................................................... Tribology is the study of adhesion, friction, lubrication and wear of surfaces in relative motion areas. The development of durable and/or low-friction surfaces and thin lubricating films has become

  3. Friction coefficient of soft contact lenses: measurements and modeling

    E-Print Network [OSTI]

    Sawyer, Wallace

    , FL 32611, USA Received 12 October 2004; accepted 16 January 2005 Tribological conditions for contact elastohydrodynamic lubrication. Finally, the largest contributors to the friction force in these experiments were comfort is related to friction. The mechanical properties of hydro- gels are extremely sensitive to water

  4. Certification of a weld produced by friction stir welding

    DOE Patents [OSTI]

    Obaditch, Chris; Grant, Glenn J

    2013-10-01T23:59:59.000Z

    Methods, devices, and systems for providing certification of friction stir welds are disclosed. A sensor is used to collect information related to a friction stir weld. Data from the sensor is compared to threshold values provided by an extrinsic standard setting organizations using a certification engine. The certification engine subsequently produces a report on the certification status of the weld.

  5. Friction Stir Welding of Lightweight Vehicle Structures: Final Report

    SciTech Connect (OSTI)

    Sanella, M.L.

    2008-08-31T23:59:59.000Z

    The purpose of this Cooperative Research and Development Agreement (CRADA) between UTBattelle, LLC and Ford Motor Company was to establish friction stir welding (FSW) and friction stir processing as viable options for use in construction of lightweight substructures for trucks and cars, including engine cradles, suspension sub frames, instrument panel supports, and intake manifolds.

  6. Model coupling friction and adhesion for steel-concrete interfaces

    E-Print Network [OSTI]

    Boyer, Edmond

    Model coupling friction and adhesion for steel- concrete interfaces Michel Raous Laboratoire de: In this paper the interface behaviour between steel and concrete, during pull out tests, is numerically a variable friction coefficient in order to simulate the behaviour of the steel-concrete interface during

  7. HOMOGENIZATION OF A VISCOELASTIC MATRIX IN LINEAR FRICTIONAL CONTACT

    E-Print Network [OSTI]

    Panchenko, Alexander

    is assumed to be dry, and the friction law is given by a version of Coulomb's law 1991 Mathematics Subject, 18, 17, 11]. The authors of these articles study the deformation of a body coming into frictional as normal compliance. The contact conditions of Coulomb type are formulated as inequalities involving

  8. Measurement of friction coefficients with the atomic force microscope

    E-Print Network [OSTI]

    Attard, Phil

    Measurement of friction coefficients with the atomic force microscope Phil Attard1, Johanna axial method for measuring the friction coefficient with the atomic force microscope is given measurement by measuring the difference between the constant compliance slopes of the extend and retract force

  9. Nonlocal microscopic theory of quantum friction between parallel metallic slabs

    SciTech Connect (OSTI)

    Despoja, Vito [Donostia International Physics Center (DIPC), P. Manuel de Lardizabal, E-20018 San Sebastian, Basque Country (Spain); Department of Physics, University of Zagreb, Bijenicka 32, HR-10000 Zagreb (Croatia); Departamento de Fisica de Materiales and Centro Mixto CSIC-UPV/EHU, Facultad de Ciencias Quimicas, Universidad del Pais Vasco UPV/EHU, Apto. 1072, E-20080 San Sebastian, Basque Country (Spain); Echenique, Pedro M. [Donostia International Physics Center (DIPC), P. Manuel de Lardizabal, E-20018 San Sebastian, Basque Country (Spain); Departamento de Fisica de Materiales and Centro Mixto CSIC-UPV/EHU, Facultad de Ciencias Quimicas, Universidad del Pais Vasco UPV/EHU, Apto. 1072, E-20080 San Sebastian, Basque Country (Spain); Sunjic, Marijan [Donostia International Physics Center (DIPC), P. Manuel de Lardizabal, E-20018 San Sebastian, Basque Country (Spain); Department of Physics, University of Zagreb, Bijenicka 32, HR-10000 Zagreb (Croatia)

    2011-05-15T23:59:59.000Z

    We present a new derivation of the friction force between two metallic slabs moving with constant relative parallel velocity, based on T=0 quantum-field theory formalism. By including a fully nonlocal description of dynamically screened electron fluctuations in the slab, and avoiding the usual matching-condition procedure, we generalize previous expressions for the friction force, to which our results reduce in the local limit. Analyzing the friction force calculated in the two local models and in the nonlocal theory, we show that for physically relevant velocities local theories using the plasmon and Drude models of dielectric response are inappropriate to describe friction, which is due to excitation of low-energy electron-hole pairs, which are properly included in nonlocal theory. We also show that inclusion of dissipation in the nonlocal electronic response has negligible influence on friction.

  10. Residuals, Sludge, and Composting (Maine)

    Broader source: Energy.gov [DOE]

    The Maine Department of Environmental Protection's Residuals, Sludge, and Composting program regulates the land application and post-processing of organic wastes, including sewage sludge, septage,...

  11. Onsager's symmetry relation and the residual parallel Reynolds stress in a magnetized plasma with electrostatic turbulence

    SciTech Connect (OSTI)

    Zuo, Yang, E-mail: yangzustc@gmail.com; Wang, Shaojie [Department of Modern Physics, University of Science and Technology of China, Hefei 230026 (China)

    2014-09-15T23:59:59.000Z

    The physics of the residual parallel Reynolds stress in a rotating plasma with electrostatic turbulence is explicitly identified by using the transport formulation of the gyrokinetic turbulence. It is clarified that the residual stress consists of four terms, among which are the cross terms due to the pressure gradient and the temperature gradient and the terms related to the turbulent acceleration impulse and the turbulent heating rate. The last two terms are identified for the first time, and are shown to cause analogous residual term in the heat flux. Meanwhile, the transport matrix reveals diffusion in the phase space. The transport matrix is demonstrated to satisfy the Onsager's symmetry relation.

  12. Experimental Study of Heat Transfer and Flow Characteristics for a New Type of Air Heater

    E-Print Network [OSTI]

    Zheng, H.; Fan, X.; Li, A.

    2006-01-01T23:59:59.000Z

    . It is found that the integrated characteristics of heat transfer and flow friction increase with the hole's diameter at the same hole density (which is equal to the ratio of the hole's total area to the baffle's area), and the heat transfer rate increases...

  13. Experimental Study of Heat Transfer and Flow Characteristics for a New Type of Air Heater 

    E-Print Network [OSTI]

    Zheng, H.; Fan, X.; Li, A.

    2006-01-01T23:59:59.000Z

    . It is found that the integrated characteristics of heat transfer and flow friction increase with the hole's diameter at the same hole density (which is equal to the ratio of the hole's total area to the baffle's area), and the heat transfer rate increases...

  14. Dynamical friction force exerted on spherical bodies

    E-Print Network [OSTI]

    O. Esquivel; B. Fuchs

    2007-04-30T23:59:59.000Z

    We present a rigorous calculation of the dynamical friction force exerted on a spherical massive perturber moving through an infinite homogenous system of field stars. By calculating the shape and mass of the polarization cloud induced by the perturber in the background system, which decelerates the motion of the perturber, we recover Chandrasekhar's drag force law with a modified Coulomb logarithm. As concrete examples we calculate the drag force exerted on a Plummer sphere or a sphere with the density distribution of a Hernquist profile. It is shown that the shape of the perturber affects only the exact form of the Coulomb logarithm. The latter converges on small scales, because encounters of the test and field stars with impact parameters less than the size of the massive perturber become inefficient. We confirm this way earlier results based on the impulse approximation of small angle scatterings.

  15. Some Hamiltonian Models of Friction II

    E-Print Network [OSTI]

    Daniel Egli; Gang Zhou

    2011-08-29T23:59:59.000Z

    In the present paper we consider the motion of a very heavy tracer particle in a medium of a very dense, non-interacting Bose gas. We prove that, in a certain mean-field limit, the tracer particle will be decelerated and come to rest somewhere in the medium. Friction is caused by emission of Cerenkov radiation of gapless modes into the gas. Mathematically, a system of semilinear integro-differential equations, introduced in [FSSG10], describing a tracer particle in a dispersive medium is investigated, and decay properties of the solution are proven. This work is an extension of [FGS10]; it is an extension because no weak coupling limit for the interaction between tracer particle and medium is assumed. The technical methods used are dispersive estimates and a contraction principle.

  16. Frictional granular mechanics: A variational approach

    SciTech Connect (OSTI)

    Holtzman, R.; Silin, D.B.; Patzek, T.W.

    2009-10-16T23:59:59.000Z

    The mechanical properties of a cohesionless granular material are evaluated from grain-scale simulations. Intergranular interactions, including friction and sliding, are modeled by a set of contact rules based on the theories of Hertz, Mindlin, and Deresiewicz. A computer generated, three-dimensional, irregular pack of spherical grains is loaded by incremental displacement of its boundaries. Deformation is described by a sequence of static equilibrium configurations of the pack. A variational approach is employed to find the equilibrium configurations by minimizing the total work against the intergranular loads. Effective elastic moduli are evaluated from the intergranular forces and the deformation of the pack. Good agreement between the computed and measured moduli, achieved with no adjustment of material parameters, establishes the physical soundness of the proposed model.

  17. High temperature low friction surface coating

    DOE Patents [OSTI]

    Bhushan, Bharat (Watervliet, NY)

    1980-01-01T23:59:59.000Z

    A high temperature, low friction, flexible coating for metal surfaces which are subject to rubbing contact includes a mixture of three parts graphite and one part cadmium oxide, ball milled in water for four hours, then mixed with thirty percent by weight of sodium silicate in water solution and a few drops of wetting agent. The mixture is sprayed 12-15 microns thick onto an electro-etched metal surface and air dried for thirty minutes, then baked for two hours at 65.degree. C. to remove the water and wetting agent, and baked for an additional eight hours at about 150.degree. C. to produce the optimum bond with the metal surface. The coating is afterwards burnished to a thickness of about 7-10 microns.

  18. Adaptive controller for regenerative and friction braking system

    DOE Patents [OSTI]

    Davis, Roy I. (Ypsilanti, MI)

    1990-01-01T23:59:59.000Z

    A regenerative and friction braking system for a vehicle having one or more roadwheels driven by an electric traction motor includes a driver responsive device for producing a brake demand signal having a magnitude corresponding to the level of braking force selected by the driver and friction and regenerative brakes operatively connected with the roadwheels of the vehicle. A system according to this invention further includes control means for operating the friction and regenerative braking subsystems so that maximum brake torques sustainable by the roadwheels of the vehicle without skidding or slipping will not be exceeded.

  19. Adaptive controller for regenerative and friction braking system

    DOE Patents [OSTI]

    Davis, R.I.

    1990-10-16T23:59:59.000Z

    A regenerative and friction braking system for a vehicle having one or more road wheels driven by an electric traction motor includes a driver responsive device for producing a brake demand signal having a magnitude corresponding to the level of braking force selected by the driver and friction and regenerative brakes operatively connected with the road wheels of the vehicle. A system according to this invention further includes control means for operating the friction and regenerative braking subsystems so that maximum brake torques sustainable by the road wheels of the vehicle without skidding or slipping will not be exceeded. 8 figs.

  20. Power-law friction in closely-packed granular materials

    E-Print Network [OSTI]

    Takahiro Hatano

    2007-05-08T23:59:59.000Z

    In order to understand the nature of friction in closely-packed granular materials, a discrete element simulation on granular layers subjected to isobaric plain shear is performed. It is found that the friction coefficient increases as the power of the shear rate, the exponent of which does not depend on the material constants. Using a nondimensional parameter that is known as the inertial number, the power-law can be cast in a generalized form so that the friction coefficients at different confining pressures collapse on the same curve. We show that the volume fraction also obeys a power-law.

  1. In-situ measurement of skin friction and point bearing 

    E-Print Network [OSTI]

    Rehmet, Joseph Don

    1970-01-01T23:59:59.000Z

    I M ? S IT U ME~c S UBEME6'T OF SKIN FRICTION PHD POINT BEARIiiG A Thesis JOS'- P':i QOij' REAMS T Suhmitted to th Gradua. e Colloa of Texas ASM Univer "it@ ln oar i! al f ul fl11ment of the requi ri ment for tha ~loc ~ ec of NP STE!3...-Situ Measurement of Skin Friction and Point Bearing (January 1970) Joseph D . Rehmet, B. S . , Texas A&M University Supervised by: Dr. Harry M. Coyle Field tests are made using several in-situ testing devices and limiting values of skin friction and point...

  2. The effect of Coulombic friction on spatial displacement statistics

    E-Print Network [OSTI]

    Menzel, Andreas M

    2010-01-01T23:59:59.000Z

    The phenomenon of Coulombic friction enters the stochastic description of dry friction between two solids and the statistic characterization of vibrating granular media. Here we analyze the corresponding Fokker-Planck equation including both velocity and spatial components, exhibiting a formal connection to a quantum mechanical harmonic oscillator in the presence of a delta potential. Numerical solutions for the resulting spatial displacement statistics show a crossover from exponential to Gaussian displacement statistics. We identify a transient intermediate regime that exhibits multiscaling properties arising from the contribution of Coulombic friction. These results are relevant to recent experimental studies of the displacement of colloidal particles along bilayer membrane tubes.

  3. The effect of Coulombic friction on spatial displacement statistics

    E-Print Network [OSTI]

    Andreas M. Menzel; Nigel Goldenfeld

    2011-06-23T23:59:59.000Z

    The phenomenon of Coulombic friction enters the stochastic description of dry friction between two solids and the statistic characterization of vibrating granular media. Here we analyze the corresponding Fokker-Planck equation including both velocity and spatial components, exhibiting a formal connection to a quantum mechanical harmonic oscillator in the presence of a delta potential. Numerical solutions for the resulting spatial displacement statistics show a crossover from exponential to Gaussian displacement statistics. We identify a transient intermediate regime that exhibits multiscaling properties arising from the contribution of Coulombic friction. The possible role of these effects during observations in diffusion experiments is shortly discussed.

  4. Critical scaling near jamming transition for frictional granular particles

    E-Print Network [OSTI]

    Michio Otsuki; Hisao Hayakawa

    2011-03-30T23:59:59.000Z

    The critical rheology of sheared frictional granular materials near jamming transition is numer- ically investigated. It is confirmed that there exist a true critical density which characterizes the onset of the yield stress, and two fictitious critical densities which characterize the scaling laws of rheological properties. We find the existence of a hysteresis loop between two of the critical densities for each friction coefficient. It is noteworthy that the critical scaling law for frictionless jamming transition seems to be still valid even for frictional jamming despite using fictitious critical density values.

  5. Effect of friction on disoriented chiral condensate formation

    E-Print Network [OSTI]

    A. K. Chaudhuri

    1998-09-08T23:59:59.000Z

    We have investigated the effect of friction on the DCC domain formation. We solve the Newton equation of motion for the O(4) fields, with quenched initial condition. The initial fields are randomly distributed in a Gaussian form. In one dimensional expansion, on the average, large DCC domains can not be formed. However, in some particular orbits, large instabilities may occur. This possibility also greatly diminishes with the introduction of friction. But, if the friction is large, the system may be overdamped and then, there is a possibility of large DCC domain formation in some events.

  6. Friction in (im-)miscible polymer brush systems and the role of transverse polymer-tilting

    E-Print Network [OSTI]

    Mueser, Martin

    Friction in (im-)miscible polymer brush systems and the role of transverse polymer-tilting Sissi de preferred solvent, leading to low friction and low wear rates. Here, we demonstrate, using molecular systems also show smaller friction than miscible systems, although the friction reduction is less than

  7. Friction Observer and Compensation for Control of Robots with Joint Torque Measurement

    E-Print Network [OSTI]

    De Luca, Alessandro

    Friction Observer and Compensation for Control of Robots with Joint Torque Measurement Luc Le Tien-- In this paper we introduce a friction observer for robots with joint torque sensing (in particular for the DLR. The observer output corresponds to the low-pass filtered friction torque. It is used for friction compensation

  8. Role of friction-induced torque in stick-slip motion J. Scheibert1,

    E-Print Network [OSTI]

    Role of friction-induced torque in stick-slip motion J. Scheibert1, and D.K. Dysthe1 1 PGP describing the kinematics of the transition from static friction to stick-slip motion of a linear elastic the precursors to frictional sliding and the periodic stick- slip motion are controlled by the amount of friction

  9. Attractiveness of periodic orbits in parametrically forced systems with time-increasing friction

    E-Print Network [OSTI]

    Bartuccelli, Michele

    Attractiveness of periodic orbits in parametrically forced systems with time- increasing friction with time-increasing friction Michele Bartuccelli,1,a) Jonathan Deane,1,b) and Guido Gentile2,c) 1 oscillator in the presence of friction, and study numerically how time-varying friction affects the dynamics

  10. GENERALIZED NEWTON METHODS FOR THE 2DSIGNORINI CONTACT PROBLEM WITH FRICTION

    E-Print Network [OSTI]

    Kunisch, Karl

    GENERALIZED NEWTON METHODS FOR THE 2D­SIGNORINI CONTACT PROBLEM WITH FRICTION K. KUNISCH AND G. STADLER Abstract. The 2D­Signorini contact problem with Tresca and Coulomb friction is discussed in infinite-dimensional Hilbert spaces. First, the problem with given friction (Tresca friction) is considered

  11. Friction dependence of shallow granular flows from discrete par-ticle simulations

    E-Print Network [OSTI]

    Al Hanbali, Ahmad

    Friction dependence of shallow granular flows from discrete par- ticle simulations Anthony Thornton relation for the macroscopic bed friction or basal roughness obtained from micro-scale discrete particle simulations of steady flows. We systematically vary the bed friction by changing the contact friction

  12. Hands-On and Minds-On Modeling Activities to Improve Students' Conceptions of Microscopic Friction

    E-Print Network [OSTI]

    Zollman, Dean

    Hands-On and Minds-On Modeling Activities to Improve Students' Conceptions of Microscopic Friction of microscopic friction. We will also present our investigation on the relative effectiveness of the use, it is possible to facilitate the refinement of students' ideas of microscopic friction. Keywords: friction

  13. Friction, Adhesion, and Deformation: Dynamic Measurements with the Atomic Force Phil Attard

    E-Print Network [OSTI]

    Attard, Phil

    Friction, Adhesion, and Deformation: Dynamic Measurements with the Atomic Force Microscope Phil. Adhesion Sci. Technol. 16, 753­791 (2002).) Running title: Friction, Adhesion, and Deformation Abstract for the friction force microscope, quantitative measurements of friction and the ef- fect of adhesion, measurement

  14. A liquid-crystal model for friction C.H. A. Cheng

    E-Print Network [OSTI]

    Shkoller, Steve

    for sliding friction. Dry friction between two sliding surfaces gen- erates granulation, resultingA liquid-crystal model for friction C.H. A. Cheng , L. H. Kellogg , S. Shkoller , and D. L, University of California, Davis, CA 95616 Contributed by D. L. Turcotte, November 19, 2007 Rate-and-state-friction

  15. High Friction from a Stiff Polymer Using Microfiber Arrays C. Majidi,1,* R. E. Groff,1

    E-Print Network [OSTI]

    Fearing, Ron

    2006) High dry friction requires intimate contact between two surfaces and is generally obtained using friction [1]. Dry friction of stiff polymers (E 1 GPa) [2,3] and rubbers [1,4,5] on glass is a wellHigh Friction from a Stiff Polymer Using Microfiber Arrays C. Majidi,1,* R. E. Groff,1 Y. Maeno,2 B

  16. Torsion Spring Oscillator with Dry Friction Summary of the Principal Formulas

    E-Print Network [OSTI]

    Butikov, Eugene

    Torsion Spring Oscillator with Dry Friction ­ Problems Summary of the Principal Formulas The differential equation of motion of an oscillator acted upon by dry friction: J ¨ = -D( + m) for > 0, J ¨ = -D cases in which the effects either of viscous friction or of dry friction predominate: a = 4m T = 4 m

  17. A rate and state friction law for saline ice Ben Lishman,1

    E-Print Network [OSTI]

    Feltham, Daniel

    coefficient of friction. This law describes dry friction. Bowden and Hughes [1939] proposed that the lowA rate and state friction law for saline ice Ben Lishman,1 Peter Sammonds,1,2 and Danny Feltham2 ice friction models are necessary to predict the nature of interactions between sea ice floes

  18. On the microphysical foundations of rate-and-state friction Thibaut Putelat,a,c

    E-Print Network [OSTI]

    Dawes, Jon

    -and-state formulation of dry friction is well established as a phenomenological yet quantitative description of dry in the evolution of frictional stick-slip processes. This overturned the classical idea of Coulomb frictionOn the microphysical foundations of rate-and-state friction Thibaut Putelat,a,c , Jonathan H. P

  19. Numerical analysis of a one-dimensional elastodynamic model of dry friction and unilateral contact

    E-Print Network [OSTI]

    Renard, Yves - Pôle de Mathématiques, Institut National des Sciences Appliquées de Lyon

    .e. hyperbolic) model with dry friction. Since we consider a Coulomb friction law with a slip velocity dependentNumerical analysis of a one-dimensional elastodynamic model of dry friction and unilateral contact in the numerical analysis of more elaborated dynamic purely elastic problems with dry friction. Ó 2001 Elsevier

  20. Coulomb and viscous friction fault detection with application to a pneumatic actuator

    E-Print Network [OSTI]

    Dunbar, William

    Coulomb and viscous friction fault detection with application to a pneumatic actuator W.B. Dunbar of friction (fault) presented in this paper could facilitate the compensation of dry friction in high precision position- ing mechanisms. Moreover, a fault detection technique for monitoring dry friction would

  1. Rolling friction for hard cylinder and sphere on viscoelastic solid

    E-Print Network [OSTI]

    B. N. J. Persson

    2010-08-26T23:59:59.000Z

    We calculate the friction force acting on a hard cylinder or spherical ball rolling on a flat surface of a viscoelastic solid. The rolling friction coefficient depends non-linearly on the normal load and the rolling velocity. For a cylinder rolling on a viscoelastic solid characterized by a single relaxation time Hunter has obtained an exact result for the rolling friction, and our result is in very good agreement with his result for this limiting case. The theoretical results are also in good agreement with experiments of Greenwood and Tabor. We suggest that measurements of rolling friction over a wide range of rolling velocities and temperatures may constitute an useful way to determine the viscoelastic modulus of rubber-like materials.

  2. Friction Stir and Ultrasonic Solid State Joining of Magnesium...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    and Ultrasonic Solid State Joining of Magnesium to Steel Friction Stir and Ultrasonic Solid State Joining of Magnesium to Steel 2012 DOE Hydrogen and Fuel Cells Program and Vehicle...

  3. On the friction coefficient of straight-chain aggregates

    E-Print Network [OSTI]

    Lorenzo Isella; Yannis Drossinos

    2011-01-31T23:59:59.000Z

    A methodology to calculate the friction coefficient of an aggregate in the continuum regime is proposed. The friction coefficient and the monomer shielding factors, aggregate-average or individual, are related to the molecule-aggregate collision rate that is obtained from the molecular diffusion equation with an absorbing boundary condition on the aggregate surface. Calculated friction coefficients of straight chains are in very good agreement with previous results, suggesting that the friction coefficients may be accurately calculated from the product of the collision rate and an average momentum transfer,the latter being independent of aggregate morphology. Langevin-dynamics simulations show that the diffusive motion of straight-chain aggregates may be described either by a monomer-dependent or an aggregate-average random force, if the shielding factors are appropriately chosen.

  4. Friction and Wear Enhancement of Titanium Alloy Engine Components...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    1 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and Peer Evaluation pm007blau2011o.pdf More Documents & Publications Friction and...

  5. Friction Stir Spot Welding of Advanced High Strength Steels ...

    Energy Savers [EERE]

    Stir Spot Welding of Advanced High Strength Steels (AHSS) Friction Stir Spot Welding of Advanced High Strength Steels (AHSS) Presentation from the U.S. DOE Office of Vehicle...

  6. Structural connections in plywood friction-fit construction

    E-Print Network [OSTI]

    Wagner, Mali E. (Mali Esther)

    2014-01-01T23:59:59.000Z

    CNC mills allow precise fabrication of planar parts with embedded joinery which can be assembled into complex 3D geometries without the use of foreign mechanical fasteners. This thesis studies the behavior of the friction-fit ...

  7. Artificial Tribotactic Microscopic Walkers: Walking Based on Friction Gradients

    E-Print Network [OSTI]

    Steimel, Joshua P.

    Friction, the resistive force between two surfaces sliding past each other, is at the core of a wide diversity of locomotion schemes. While such schemes are well described for homogeneous environments, locomotion based on ...

  8. Frictional properties of faults: from observation on the

    E-Print Network [OSTI]

    Winfree, Erik

    Frictional properties of faults: from observation on the Longitudinal Valley Fault, Taiwan myself lucky to do what I love and to wake up every day, happy and excited about the day to come

  9. The development of an experimental procedure to determine the amount of active internal friction in a rotor-bearing system

    E-Print Network [OSTI]

    Parker, Jeffrey Scott

    1997-01-01T23:59:59.000Z

    frequency equivalent viscous friction coefficient (Coulomb friction) equivalent viscous friction coefficient (hys', cretic friction) Young's modulus (psi) internal friction force per unit length (lbs) total shaft internal friction force (lbs... friction force is now generally believed to be hysteretic (resistance to elongation and contraction of material fibers, also called anelasticity) or Coulomb (relative motion between two materials at a joint) rather ihan viscous. In 1976, II. F. Black...

  10. Small mass asymptotic for the motion with vanishing friction

    E-Print Network [OSTI]

    Mark Freidlin; Wenqing Hu; Alexander Wentzell

    2012-08-30T23:59:59.000Z

    We consider the small mass asymptotic (Smoluchowski-Kramers approximation) for the Langevin equation with a variable friction coefficient. The friction coefficient is assumed to be vanishing within certain region. We introduce a regularization for this problem and study the limiting motion for the 1-dimensional case and a multidimensional model problem. The limiting motion is a Markov process on a projected space. We specify the generator and boundary condition of this limiting Markov process and prove the convergence.

  11. The dependence of the dry friction threshold on rupture dynamics

    E-Print Network [OSTI]

    Ben-David, Oded

    2011-01-01T23:59:59.000Z

    The static friction coefficient between two materials is considered to be a material constant. We present experiments demonstrating that the ratio of shear to normal force needed to move contacting blocks can, instead, vary systematically with controllable changes in the external loading configuration. Large variations in both the friction coefficient and consequent stress drop are tightly linked to changes in the rupture dynamics of the rough interface separating the two blocks.

  12. Seismic Interstory Drift Demands in Steel Friction Damped Braced Buildings 

    E-Print Network [OSTI]

    Peternell Altamira, Luis E.

    2010-01-16T23:59:59.000Z

    ) ......................................................................................... 31 viii Page Figure 4.4: Coulomb and Viscous Friction block (TheMathWorks 2008) ...................... 33 Figure 4.5: SIMULINK model for verification of the SAP2000 friction damped brace model behavior... of the SAP2000 analytical model of the FDB .................................................... 33 Table 5.1: Peak interstory drift ratio of the different damper configurations subjected to the series of BSE-1 records...

  13. Bar-halo Friction in Galaxies I: Scaling Laws

    E-Print Network [OSTI]

    J. A. Sellwood

    2005-09-28T23:59:59.000Z

    It has been known for some time that rotating bars in galaxies slow due to dynamical friction against the halo. However, recent attempts to use this process to place constraints on the dark matter density in galaxies and possibly also to drive dark matter out of the center have been challenged. This paper uses simplified numerical experiments to clarify several aspects of the friction mechanism. I explicitly demonstrate the Chandrasekhar scaling of the friction force with bar mass, halo density, and halo velocity dispersion. I present direct evidence that exchanges between the bar and halo orbits at major resonances are responsible for friction and study both individual orbits and the net changes at these resonances. I also show that friction alters the phase space density of particles in the vicinity of a major resonance, which is the reason the magnitude of the friction force depends on the prior evolution. I demonstrate that bar slow down can be captured correctly in simulations having modest spatial resolution and practicable numbers of particles. Subsequent papers in this series delineate the dark matter density that can be tolerated in halos of different density profiles.

  14. Bar-Halo Friction in Galaxies II: Metastability

    E-Print Network [OSTI]

    J. A. Sellwood; Victor P. Debattista

    2005-11-05T23:59:59.000Z

    It is well-established that strong bars rotating in dense halos generally slow down as they lose angular momentum to the halo through dynamical friction. Angular momentum exchanges between the bar and halo particles take place at resonances. While some particles gain and others lose, friction arises when there is an excess of gainers over losers. This imbalance results from the generally decreasing numbers of particles with increasing angular momentum, and friction can therefore be avoided if there is no gradient in the density of particles across the major resonances. Here we show that anomalously weak friction can occur for this reason if the pattern speed of the bar fluctuates upwards. After such an event, the density of resonant halo particles has a local inflexion created by the earlier exchanges, and bar slowdown can be delayed for a long period; we describe this as a metastable state. We show that this behavior in purely collisionless N-body simulations is far more likely to occur in methods with adaptive resolution. We also show that the phenomenon could arise in nature, since bar-driven gas inflow could easily raise the bar pattern speed enough to reach the metastable state. Finally, we demonstrate that mild external, or internal, perturbations quickly restore the usual frictional drag, and it is unlikely therefore that a strong bar in a galaxy having a dense halo could rotate for a long period without friction.

  15. Spindown of magnetars: Quantum Vacuum Friction?

    E-Print Network [OSTI]

    Xiong, Xue-Yu; Xu, Ren-Xin

    2015-01-01T23:59:59.000Z

    Magnetars are proposed to be peculiar neutron stars which could power their X-ray radiation by super-strong magnetic fields as high as $\\gtrsim 10^{14}$ G. However, no direct evidence for such strong fields is obtained till now, and the recent discovery of low magnetic field magnetars even indicates that some more efficient radiation mechanism than magnetic dipole radiation should be included. % In this paper, quantum vacuum friction (QVF) is suggested to be a direct consequence of super-strong {\\em surface} fields, therefore the magnetar model could then be tested further through the QVF braking. % Pulsars interact with the quantum vacuum in high surface magnetic field, which results in a significantly high spindown rate ( $\\dot{P}$ ). It is found that QVF dominates the energy loss of pulsars when $B_{\\rm surf}\\cdot P>10^{11}(10^{10})$G$\\cdot$s if the ratio $\\xi$ of the surface magnetic field over diploe magnetic field is 10(100), with $B_{\\rm surf}$ the surface magnetic field and $P$ the rotation period. % ...

  16. Yield criteria for quasibrittle and frictional materials

    E-Print Network [OSTI]

    Davide Bigoni; Andrea Piccolroaz

    2010-10-09T23:59:59.000Z

    A new yield/damage function is proposed for modelling the inelastic behaviour of a broad class of pressure-sensitive, frictional, ductile and brittle-cohesive materials. The yield function allows the possibility of describing a transition between the shape of a yield surface typical of a class of materials to that typical of another class of materals. This is a fundamental key to model the behaviour of materials which become cohesive during hardening (so that the shape of the yield surface evolves from that typical of a granular material to that typical of a dense material), or which decrease cohesion due to damage accumulation. The proposed yield function is shown to agree with a variety of experimental data relative to soil, concrete, rock, metallic and composite powders, metallic foams, porous metals, and polymers. The yield function represents a single, convex and smooth surface in stress space approaching as limit situations well-known criteria and the extreme limits of convexity in the deviatoric plane. The yield function is therefore a generalization of several criteria, including von Mises, Drucker-Prager, Tresca, modified Tresca, Coulomb-Mohr, modified Cam-clay, and --concerning the deviatoric section-- Rankine and Ottosen. Convexity of the function is proved by developing two general propositions relating convexity of the yield surface to convexity of the corresponding function. These propositions are general and therefore may be employed to generate other convex yield functions.

  17. Susanville District Heating District Heating Low Temperature...

    Open Energy Info (EERE)

    Susanville District Heating District Heating Low Temperature Geothermal Facility Jump to: navigation, search Name Susanville District Heating District Heating Low Temperature...

  18. Total Space Heating Water Heating Cook-

    Gasoline and Diesel Fuel Update (EIA)

    Released: September, 2008 Total Space Heating Water Heating Cook- ing Other Total Space Heating Water Heating Cook- ing Other All Buildings* ... 1,602 1,397...

  19. Total Space Heating Water Heating Cook-

    Gasoline and Diesel Fuel Update (EIA)

    Energy Consumption Survey: Energy End-Use Consumption Tables Total Space Heating Water Heating Cook- ing Other Total Space Heating Water Heating Cook- ing Other All...

  20. Total Space Heating Water Heating Cook-

    Gasoline and Diesel Fuel Update (EIA)

    Released: September, 2008 Total Space Heating Water Heating Cook- ing Other Total Space Heating Water Heating Cook- ing Other All Buildings* ... 1,870 1,276...

  1. Total Space Heating Water Heating Cook-

    Gasoline and Diesel Fuel Update (EIA)

    Released: September, 2008 Total Space Heating Water Heating Cook- ing Other Total Space Heating Water Heating Cook- ing Other All Buildings ... 2,037...

  2. Chemical Characterization of Individual Particles and Residuals...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Individual Particles and Residuals of Cloud Droplets and Ice Crystals Collected On Board Research Chemical Characterization of Individual Particles and Residuals of Cloud Droplets...

  3. Couette flow regimes with heat transfer in rarefied gas

    SciTech Connect (OSTI)

    Abramov, A. A., E-mail: alabr54@mail.ru; Butkovskii, A. V., E-mail: albutkov@mail.ru [Zhukovski Central Aerohydrodynamics Institute (Russian Federation)

    2013-06-15T23:59:59.000Z

    Based on numerical solution of the Boltzmann equation by direct statistic simulation, the Couette flow with heat transfer is studied in a broad range of ratios of plate temperatures and Mach numbers of a moving plate. Flow regime classification by the form of the dependences of the energy flux and friction stress on the Knudsen number Kn is proposed. These dependences can be simultaneously monotonic and nonmonotonic and have maxima. Situations are possible in which the dependence of the energy flux transferred to a plate on Kn has a minimum, while the dependence of the friction stress is monotonic or even has a maximum. Also, regimes exist in which the dependence of the energy flux on Kn has a maximum, while the dependence of the friction stress is monotonic, and vice versa.

  4. DISSOLUTION OF NEPTUNIUM OXIDE RESIDUES

    SciTech Connect (OSTI)

    Kyser, E

    2009-01-12T23:59:59.000Z

    This report describes the development of a dissolution flowsheet for neptunium (Np) oxide (NpO{sub 2}) residues (i.e., various NpO{sub 2} sources, HB-Line glovebox sweepings, and Savannah River National Laboratory (SRNL) thermogravimetric analysis samples). Samples of each type of materials proposed for processing were dissolved in a closed laboratory apparatus and the rate and total quantity of off-gas were measured. Samples of the off-gas were also analyzed. The quantity and type of solids remaining (when visible) were determined after post-dissolution filtration of the solution. Recommended conditions for dissolution of the NpO{sub 2} residues are: Solution Matrix and Loading: {approx}50 g Np/L (750 g Np in 15 L of dissolver solution), using 8 M nitric acid (HNO{sub 3}), 0.025 M potassium fluoride (KF) at greater than 100 C for at least 3 hours. Off-gas: Analysis of the off-gas indicated nitric oxide (NO), nitrogen dioxide (NO{sub 2}) and nitrous oxide (N{sub 2}O) as the only identified components. No hydrogen (H{sub 2}) was detected. The molar ratio of off-gas produced per mole of Np dissolved ranged from 0.25 to 0.4 moles of gas per mole of Np dissolved. A peak off-gas rate of {approx}0.1 scfm/kg bulk oxide was observed. Residual Solids: Pure NpO{sub 2} dissolved with little or no residue with the proposed flowsheet but the NpCo and both sweepings samples left visible solid residue after dissolution. For the NpCo and Part II Sweepings samples the residue amounted to {approx}1% of the initial material, but for the Part I Sweepings sample, the residue amounted to {approx}8 % of the initial material. These residues contained primarily aluminum (Al) and silicon (Si) compounds that did not completely dissolve under the flowsheet conditions. The residues from both sweepings samples contained minor amounts of plutonium (Pu) particles. Overall, the undissolved Np and Pu particles in the residues were a very small fraction of the total solids.

  5. Heating system

    SciTech Connect (OSTI)

    Nishman, P.J.

    1983-03-08T23:59:59.000Z

    A heating system utilizing solar panels and buried ground conduits to collect and store heat which is delivered to a heatpump heat exchanger. A heat-distribution fluid continuously circulates through a ground circuit to transfer heat from the ground to the heat exchanger. The ground circuit includes a length of buried ground conduit, a pump, a check valve and the heat exchanger. A solar circuit, including a solar panel and a second pump, is connected in parallel with the check valve so that the distribution fluid transfers solar heat to the heat exchanger for utilization and to the ground conduit for storage when the second pump is energized. A thermostatically instrumented control system energizes the second pump only when the temperature differential between the solar panel inlet and outlet temperatures exceeds a predetermined value and the ground temperature is less than a predetermined value. Consequently, the distribution fluid flows through the solar panel only when the panel is capable of supplying significant heat to the remainder of the system without causing excessive drying of the ground.

  6. Polymer Effects on Heat Transport in Laminar Boundary Layer Flow

    E-Print Network [OSTI]

    Roberto Benzi; Emily S. C. Ching; Vivien W. S. Chu

    2011-04-27T23:59:59.000Z

    We consider a laminar Blasius boundary-layer flow above a slightly heated horizontal plate and study the effect of polymer additives on the heat transport. We show that the action of the polymers can be understood as a space-dependent effective viscosity that first increases from the zero-shear value then decreases exponentially back to the zero-shear value as one moves away from the boundary. We find that with such an effective viscosity, both the horizontal and vertical velocities near the plate are decreased thus leading to an increase in the friction drag and a decrease in the heat transport in the flow.

  7. The influence of quench sensitivity on residual stresses in the aluminium alloys 7010 and 7075

    SciTech Connect (OSTI)

    Robinson, J.S., E-mail: jeremy.robinson@ul.ie [Materials and Surface Science Institute, University of Limerick (Ireland); Tanner, D.A. [Materials and Surface Science Institute, University of Limerick (Ireland); Truman, C.E. [Department of Mechanical Engineering, University of Bristol (United Kingdom); Paradowska, A.M. [ISIS Facility, Rutherford Appleton Laboratory, Didcot (United Kingdom); Wimpory, R.C. [Helmholtz Centre Berlin for Materials and Energy, Hahn Meitner Platz 1, Berlin (Germany)

    2012-03-15T23:59:59.000Z

    The most critical stage in the heat treatment of high strength aluminium alloys is the rapid cooling necessary to form a supersaturated solid solution. A disadvantage of quenching is that the thermal gradients can be sufficient to cause inhomogeneous plastic deformation which in turn leads to the development of large residual stresses. Two 215 mm thick rectilinear forgings have been made from 7000 series alloys with widely different quench sensitivity to determine if solute loss in the form of precipitation during quenching can significantly affect residual stress magnitudes. The forgings were heat treated and immersion quenched using cold water to produce large magnitude residual stresses. The through thickness residual stresses were measured by neutron diffraction and incremental deep hole drilling. The distribution of residual stresses was found to be similar for both alloys varying from highly triaxial and tensile in the interior, to a state of biaxial compression in the surface. The 7010 forging exhibited larger tensile stresses in the interior. The microstructural variation from surface to centre for both forgings was determined using optical and transmission electron microscopy. These observations were used to confirm the origin of the hardness variation measured through the forging thickness. When the microstructural changes were accounted for in the through thickness lattice parameter, the residual stresses in the two forgings were found to be very similar. Solute loss in the 7075 forging appeared to have no significant effect on the residual stress magnitudes when compared to 7010. - Highlights: Black-Right-Pointing-Pointer Through thickness residual stress measurements made on large Al alloy forgings. Black-Right-Pointing-Pointer Residual stress characterised using neutron diffraction and deep hole drilling. Black-Right-Pointing-Pointer Biaxial compressive surface and triaxial subsurface residual stresses. Black-Right-Pointing-Pointer Quench sensitivity of 7075 promotes significant microstructural differences to 7010. Black-Right-Pointing-Pointer When precipitation is accounted for, residual stress in both forgings are similar.

  8. Non-Contact Friction for Ion-Surface Interactions

    E-Print Network [OSTI]

    U. D. Jentschura; G. Lach

    2015-04-21T23:59:59.000Z

    Non-contact friction forces are exerted on physical systems through dissipative processes, when the two systems are not in physical contact with each other, or, in quantum mechanical terms, when the overlap of their wave functions is negligible. Non-contact friction is mediated by the exchange of virtual quanta, with the additional requirement that the scattering process needs to have an inelastic component. For finite-temperature ion-surface interactions, the friction is essentially caused by Ohmic resistance due to the motion of the image charge moving in a dielectric material. A conceivable experiment is difficult because the friction force needs to be isolated from the interaction with the image charge, which significantly distorts the ion's flight path. We propose an experimental setup which is designed to minimize the influence of the image charge interaction though a compensation mechanism, and evaluate the energy loss due to non-contact friction for helium ions (He+) interacting with gold, vanadium, titanium and graphite surfaces. Interactions with the infinite series of mirror charges in the plates are summed in terms of the logarithmic derivatives of the Gamma function, and of the Hurwitz zeta function.

  9. DHE (downhole heat exchangers). [Downhole Heat Exchangers (DHE)

    SciTech Connect (OSTI)

    Culver, G.

    1990-11-01T23:59:59.000Z

    The use of downhole heat exchangers (DHE) for residential or commercial space and domestic water heating and other applications has several desirable features. Systems are nearly or completely passive -- that is, no or very little geothermal water or steam is produced from the well either reducing or completely eliminating surface environmental concerns and the need for disposal systems or injection wells. Initial cost of pumps and installation are eliminated or reduced along with pumping power costs and maintenance costs associated with pumping often corrosive geothermal fluids. Many residential and small commercial systems do not require circulating pumps because the density difference in the incoming and outgoing sides of the loop are sufficient to overcome circulating friction losses in the entire system. The major disadvantage of DHEs is their dependence on natural heat flow. In areas where geological conditions provide high permeability and a natural hydraulic gradient, DHEs can provide a substantial quantity of heat. A single 500-ft (152 m) well in Klamath Falls, Oregon, supplies over one megawatt thermal and output is apparently limited by the surface area of pipe that can be installed in the well bore. In contrast, DHEs used in conjunction with heat pumps may supply less than 8 KW from a well of similar depth. Here output is limited by conductive heat flow with perhaps a small contribution from convection near the well bore. The highest capacity DHE reported to date, in Turkey, supplies 6 MW thermal from an 820-ft (250 m) well. There were two main goals for this project. The first was to gather, disseminate and exchange internationally information on DHES. The second was to perform experiments that would provide insight into well bore/aquifer interaction and thereby provide more information on which to base DHE designs. 27 refs., 31 figs., 3 tabs.

  10. Investigation of Skin Tribology and Its Effects on Coefficient of Friction and Other Tactile Attributes Involving Polymer Applications 

    E-Print Network [OSTI]

    Darden, Matthew Aguirre

    2012-02-14T23:59:59.000Z

    concerning tactility, examining environmental and material properties that affect skin on fabric coefficient of friction. In this study, similar friction procedure was used to compare coefficients of friction of a fingerpad across varying polymer fabrics...

  11. Residual activation of accelerator components

    SciTech Connect (OSTI)

    Rakhno, I.L.; Mokhov, N.V.; Striganov, S.I.; /Fermilab

    2008-02-01T23:59:59.000Z

    A method to calculate residual activation of accelerator components is presented. A model for residual dose estimation for thick objects made of arbitrary composite materials for arbitrary irradiation and cooling times is employed in this study. A scaling procedure is described to apply the model to thin objects with linear dimensions less than a fraction of a nuclear interaction length. The scaling has been performed for various materials and corresponding factors have been determined for objects of certain shapes (slab, solid and hollow cylinder) that can serve as models for beam pipes, magnets and collimators. Both contact residual dose and dose attenuation in the air outside irradiated objects are considered. A relation between continuous and impulse irradiation is accounted for as well.

  12. Dry Friction Avalanches: Experiment and Robin Hood model

    E-Print Network [OSTI]

    Sergey V. Buldyrev; John Ferrante; Fredy R. Zypman

    2005-11-01T23:59:59.000Z

    This paper presents experimental evidence and theoretical models supporting that dry friction stick-slip is described by self-organized criticality. We use the data, obtained with a pin-on-disc tribometer set to measure lateral force to examine the variation of the friction force as a function of time. We study nominally flat surfaces of aluminum and steel. The probability distribution of force jumps follows a power law with exponents $\\mu$ in the range 2.2 -- 5.4. The frequency power spectrum follows a $1/{f^\\alpha}$ pattern with $\\alpha$ in the range 1 -- 2.6. In addition, we present an explanation of these power-laws observed in the dry friction experiments based on the Robin Hood model of self organized criticality. We relate the values of the exponents characterizing these power laws to the critical exponents $D$ an $\

  13. Quantum Friction: Cooling Quantum Systems with Unitary Time Evolution

    E-Print Network [OSTI]

    Aurel Bulgac; Michael McNeil Forbes; Kenneth J. Roche; Gabriel Wlaz?owski

    2013-05-29T23:59:59.000Z

    We introduce a type of quantum dissipation -- local quantum friction -- by adding to the Hamiltonian a local potential that breaks time-reversal invariance so as to cool the system. Unlike the Kossakowski-Lindblad master equation, local quantum friction directly effects unitary evolution of the wavefunctions rather than the density matrix: it may thus be used to cool fermionic many-body systems with thousands of wavefunctions that must remain orthogonal. In addition to providing an efficient way to simulate quantum dissipation and non-equilibrium dynamics, local quantum friction coupled with adiabatic state preparation significantly speeds up many-body simulations, making the solution of the time-dependent Schr\\"odinger equation significantly simpler than the solution of its stationary counterpart.

  14. Evaluation of friction loss in flexible and galvanized duct 

    E-Print Network [OSTI]

    Zimmermann, Carlos Michael Alberto

    1985-01-01T23:59:59.000Z

    or similar exterior material. 3. When exterior abrasion of the duct can be a factor, a vinyl scuff strip can be glued or plastic welded in spiral fashion on the outside cover. 4. Reduction in flow because of Internal friction can be minimized by using...EVALUATION OF FRICTION LOSS IN FLEXIBLE AND GALVANIZED DUCT A Thesis by CARLOS MICHAEL ALBERTO ZIMMERMANN Submitted to the Graduate College of Texas A&M University in partial fulfliiment of the requirements for the degree of MASTER...

  15. Effects of mechanical properties and surface friction on elasto-plastic sliding contact

    E-Print Network [OSTI]

    Suresh, Subra

    Effects of mechanical properties and surface friction on elasto-plastic sliding contact S and many recent computational studies have established quantitative relationships between elasto-plastic systematically quantified the effect of the plastic deformation characteristics on the frictional sliding

  16. Usage of Friction-damped Braced Frames for Seismic Vibration Control

    E-Print Network [OSTI]

    Fink, Brynnan 1992-

    2012-04-16T23:59:59.000Z

    This study presents the results of experimental work that examines the functionality of friction-damped braced frames during seismic events. The simplicity and efficacy of this friction device as a means of passive vibration control suggest...

  17. Identification and compensation of friction for a dual stage positioning system

    E-Print Network [OSTI]

    Thimmalapura, Satish Voddina

    2005-11-01T23:59:59.000Z

    and velocity as compared to conventional friction models which are dependent on the direction of motion. Static and Coulomb friction were modelled as functions of velocity and position. This model was able to predict the behavior of the coarse stage...

  18. Numerical Study on Transverse Friction of a Slender Rod Contacting the Seabed

    E-Print Network [OSTI]

    Lu, Hang

    2012-10-19T23:59:59.000Z

    based upon a Coulomb model originally developed for the simulation of the friction in all dry contact mechanical systems. In applying the Coulomb model, the transverse friction depends on the transverse displacement and/or velocity of a slender rod...

  19. THE DYNAMICS OF A RAILWAY WAGON WHEEL SET WITH DRY FRICTION DAMPING

    E-Print Network [OSTI]

    stick-slip and hysteresis in our model of the dry friction and assume that Coulomb's friction law holds-rail interaction and this simplicity might be a contributing factor to the derailments. In this article a more

  20. Piston ring design for reduced friction in modern internal combustion engines

    E-Print Network [OSTI]

    Smedley, Grant, 1978-

    2004-01-01T23:59:59.000Z

    Piston ring friction losses account for approximately 20% of the total mechanical losses in modern internal combustion engines. A reduction in piston ring friction would therefore result in higher efficiency, lower fuel ...

  1. Corrosive resistant heat exchanger

    DOE Patents [OSTI]

    Richlen, Scott L. (Annandale, VA)

    1989-01-01T23:59:59.000Z

    A corrosive and errosive resistant heat exchanger which recovers heat from a contaminated heat stream. The heat exchanger utilizes a boundary layer of innocuous gas, which is continuously replenished, to protect the heat exchanger surface from the hot contaminated gas. The innocuous gas is conveyed through ducts or perforations in the heat exchanger wall. Heat from the heat stream is transferred by radiation to the heat exchanger wall. Heat is removed from the outer heat exchanger wall by a heat recovery medium.

  2. Dry friction between laser-patterned surfaces: Role of alignment, structural wavelength and

    E-Print Network [OSTI]

    Mueser, Martin

    1 Dry friction between laser-patterned surfaces: Role of alignment, structural wavelength.gachot@mx.uni-saarland.de Abstract The ability to tune friction by tailoring surface topographies at micron length scales friction between laser-textured surfaces. Line-like laser patterns with varying structural wavelengths

  3. Adaptive Friction Compensation for Servo J. Wang, S. S. Ge, and T. H. Lee

    E-Print Network [OSTI]

    Ge, Shuzhi Sam

    Adaptive Friction Compensation for Servo Mechanisms J. Wang, S. S. Ge, and T. H. Lee Department@nus.edu.sg Abstract Friction exists in all machines having relative motion, and plays an important role in many servo, accurate friction modeling and effective compensation techniques have to be investigated. In this chapter

  4. Friction of a slider on a granular layer: Nonmonotonic thickness dependence and effect of boundary conditions

    E-Print Network [OSTI]

    Kudrolli, Arshad

    Friction of a slider on a granular layer: Nonmonotonic thickness dependence and effect of boundary the effective friction encountered by a mass sliding on a granular layer as a function of bed thickness and boundary roughness conditions. The observed friction has minima for a small number of layers before

  5. Friction of partially embedded vertically aligned carbon nanofibers inside Burak Aksak and Metin Sittia

    E-Print Network [OSTI]

    Goldstein, Seth Copen

    Friction of partially embedded vertically aligned carbon nanofibers inside elastomers Burak Aksak partially embedded inside polyurethane eVACNFs are proposed as a robust high friction fibrillar material and selective oxygen plasma etching, fibers are partially released up to 5 m length. Macroscale friction

  6. Creeping Friction Dynamics and Molecular Dissipation Mechanisms in Glassy Polymers Scott Sills and Rene M. Overney

    E-Print Network [OSTI]

    Creeping Friction Dynamics and Molecular Dissipation Mechanisms in Glassy Polymers Scott Sills kinetic friction between an atomic force microscopy tip and a surface of amorphous glassy polystyrene has of the friction results using the method of reduced variables revealed the dissipative behavior as an activated

  7. Noise and vibration for a self-excited mechanical system with friction

    E-Print Network [OSTI]

    Boyer, Edmond

    Noise and vibration for a self-excited mechanical system with friction K. Soobbarayen1,a , S. The contact is modelled by introducing several local contact elements at the friction interface and a cubic contact law is used to describe the contact force. The classical Coulomb law is applied to model friction

  8. Analysis of a unilateral contact problem taking into account adhesion and friction

    E-Print Network [OSTI]

    Rossi, Riccarda

    Analysis of a unilateral contact problem taking into account adhesion and friction Elena Bonetti) adhesion and of the friction are taken into account. We describe the adhesion phenomenon in terms conditions and the friction by a nonlocal Coulomb law. All the constraints on the internal variables as well

  9. Long term friction: From stick-slip to stable sliding Christophe Voisin,1

    E-Print Network [OSTI]

    Long term friction: From stick-slip to stable sliding Christophe Voisin,1 Franc¸ois Renard,1 July 2007. [1] We have devised an original laboratory experiment where we investigate the frictional properties, salt, an analogue for natural faults, allows for frictional processes plastic deformation

  10. Friction and curvature judgement Chris Christou (1) and Alan Wing (2)

    E-Print Network [OSTI]

    Friction and curvature judgement Chris Christou (1) and Alan Wing (2) (1) Optometry resistance to motion due to friction. This resistance creates a force vector which varies in direction with friction. But the vector also varies in direction with the curvature of the surface traversed by the finger

  11. A parallel and multiscale strategy for the parametric study of transient dynamic problems with friction

    E-Print Network [OSTI]

    with friction P.-A. Boucard1, D. Odi`evre1 and F. Gatuingt1 LMT-Cachan (ENS Cachan/CNRS/Universit´e Paris 6/PRES with friction. Our approach is based on the multiscale LATIN method with domain decomposition. This is a mixed; transient dynamics; domain decomposition; contact; friction; parallel processing 1. INTRODUCTION Modeling

  12. FRICTION AND THE INVERTED PENDULUM STABILIZATION PROBLEM Sue Ann Campbell Stephanie Crawford Kirsten Morris

    E-Print Network [OSTI]

    Morris, Kirsten

    FRICTION AND THE INVERTED PENDULUM STABILIZATION PROBLEM Sue Ann Campbell Stephanie Crawford of friction on the design and performance of feedback controllers that aim to stabilize the pendulum in the upright position. We show that a controller designed using a simple viscous friction model has poor

  13. ACC03-ASME0018 Controller Design for Flexible Systems with Friction

    E-Print Network [OSTI]

    Singh, Tarunraj

    ACC03-ASME0018 Controller Design for Flexible Systems with Friction: Linear Programming Approach of friction is presented. A linear program- ming technique for finding an optimal control of linear flexible systems is extended to frictional systems. A floating oscillator is used in the development, where

  14. Attractiveness of periodic orbits in parametrically forced systems with time-increasing friction

    E-Print Network [OSTI]

    Attractiveness of periodic orbits in parametrically forced systems with time-increasing friction-dimensional systems subject to a periodic force and study numer- ically how a time-varying friction affects oscillator in the presence of friction. We find that, if the damping coefficient increases in time up

  15. Finite-element modeling of subglacial cavities and related friction law

    E-Print Network [OSTI]

    Gagliardini, Olivier

    Finite-element modeling of subglacial cavities and related friction law O. Gagliardini,1 D. Cohen,2, the friction law, can be easily extended from linear to nonlinear ice rheology and is bounded even for bedrocks with locally infinite slopes. Combining our results with earlier works by others, a phenomenological friction

  16. Internal friction in the ultrafast folding of the tryptophan cage q Linlin Qiu 1

    E-Print Network [OSTI]

    Hagen, Stephen J.

    Internal friction in the ultrafast folding of the tryptophan cage q Linlin Qiu 1 , Stephen J. Hagen is a diffusional process, and the speed of folding is controlled by the frictional forces that act important source of friction in folding reactions. By contrast, our studies of the folding dynamics

  17. Dynamic Friction Models for Longitudinal Road/Tire Interaction: Theoretical Advances

    E-Print Network [OSTI]

    Tsiotras, Panagiotis

    Dynamic Friction Models for Longitudinal Road/Tire Interaction: Theoretical Advances C. Canudas we derive a new dynamic friction force model for the longitudinal road/tire interaction for wheeled-point friction problems, called the LuGre model [1]. By assuming a con- tact patch between the tire

  18. Brownian dynamics algorithm for bead-rod semiflexible chain with anisotropic friction

    E-Print Network [OSTI]

    Natelson, Douglas

    Brownian dynamics algorithm for bead-rod semiflexible chain with anisotropic friction Alberto of semiflexible bead-rod chain with anisotropic friction can mimic closely the hydrodynamics of a slender filament dependent anisotropic bead friction coefficients. The algorithm is an extension of that given previously

  19. Dynamic Friction Models for Longitudinal Road/Tire Interaction: Experimental Results

    E-Print Network [OSTI]

    Tsiotras, Panagiotis

    Dynamic Friction Models for Longitudinal Road/Tire Interaction: Experimental Results C. Canudas dynamic friction force model for the longitudinal road/tire interaction for wheeled ground vehicles is val- idated via experiments with an actual passenger vehicle. Contrary to common static friction/slip maps

  20. DISPLAY OF FRICTION IN VIRTUAL ENVIRONMENTS BASED ON HUMAN FINGER PAD CHARACTERISTICS

    E-Print Network [OSTI]

    Hollerbach, John M.

    DISPLAY OF FRICTION IN VIRTUAL ENVIRONMENTS BASED ON HUMAN FINGER PAD CHARACTERISTICS A. Nahvi, J City, UT 84112 ABSTRACT A friction display system is proposed for virtual environ- ments. Since a user the frictional properties of the human finger pad on 9 subjects by simultaneously recording force and movement

  1. Internal Friction Controls the Speed of Protein Folding from a Compact Configuration

    E-Print Network [OSTI]

    Roder, Heinrich

    Internal Friction Controls the Speed of Protein Folding from a Compact Configuration Suzette A is independent of the cosolutes used to adjust solvent friction. Therefore, interactions within the interior. Interestingly, we find a very strong temperature dependence in these "internal friction"-controlled dynamics

  2. Analysis of a unilateral contact problem taking into account adhesion and friction

    E-Print Network [OSTI]

    Rossi, Riccarda

    Analysis of a unilateral contact problem taking into account adhesion and friction Elena Bonetti) adhesion and of the friction are taken into account. We describe the adhesion phenomenon in terms conditions, and friction by a nonlocal Coulomb law. All the constraints on the internal variables as well

  3. Friction experiments with elastography: the slow slip and the super-shear regimes

    E-Print Network [OSTI]

    Boyer, Edmond

    Friction experiments with elastography: the slow slip and the super-shear regimes S. Cathelinea , S technique derived from elastography, is used to follow the dynamic of the interface failure in a friction by Amontons in 1699 [1], the resistance to slip of an interface can be modeled by two main frictional states

  4. Dense granular ows: two-particle argument accounts for friction-like constitutive law with threshold

    E-Print Network [OSTI]

    Recanati, Catherine

    robust scaling behav- iors in various ow geomerties for dry grains, whether frictional or not [2, 4Dense granular ows: two-particle argument accounts for friction-like constitutive law a constitutive law that exhibits a ow threshold expressed as a #12;nite e#11;ective friction at ow onset

  5. Method for measurement of friction forces on single cells in microfluidic devices

    E-Print Network [OSTI]

    Ma, Hongshen

    both dry and wet conditions, are well estab- lished.16,17 The measurement of friction at micrometer the friction between dry microscopic surfaces, including atomic force microscopy, fric- tion-force microscopyMethod for measurement of friction forces on single cells in microfluidic devices Lazar

  6. Firstpassage time of Brownian motion with dry friction Yaming Chen 1, # and Wolfram Just 1, +

    E-Print Network [OSTI]

    Just, Wolfram

    First­passage time of Brownian motion with dry friction Yaming Chen 1, # and Wolfram Just 1, + 1­smooth stochastic model, namely Brownian motion with dry friction, using two di#erent but closely related approaches on the other. For the simple case containing only dry friction, a phase transi­ tion phenomenon in the spectrum

  7. Progress of Theoretical Physics Supplement 1 Simulation of granular friction and its effective theory

    E-Print Network [OSTI]

    Hayakawa, Hisao

    sliding of the plate. Similar behaviors have been observed even in atomic dry friction 4) and meltProgress of Theoretical Physics Supplement 1 Simulation of granular friction and its effective­8501 (Received ) This paper discusses the application of the distinct element method (DEM) for granular friction

  8. An analytical approach to codimension2 sliding bifurcations in the dry friction oscillator

    E-Print Network [OSTI]

    An analytical approach to codimension­2 sliding bifurcations in the dry friction oscillator M In this paper, we consider analytically sliding bifurcations of periodic orbits in the dry friction oscillator] for a detailed account of these bifurcations in the case of periodic orbits. The dry friction oscillator

  9. ensl-00178753,version1-12Oct2007 Friction and dilatancy in immersed granular matter.

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    -measurements in the dry case [8], G´eminard et al. brought to the fore a dynamic friction- coefficient µ in the caseensl-00178753,version1-12Oct2007 Friction and dilatancy in immersed granular matter. T. Divoux'Italie, 69364 Lyon cedex 07, France. The friction of a sliding plate on a thin immersed granular layer obeys

  10. An analytical approach to codimension-2 sliding bifurcations in the dry friction oscillator

    E-Print Network [OSTI]

    Politècnica de Catalunya, Universitat

    An analytical approach to codimension-2 sliding bifurcations in the dry friction oscillator M consider analytically sliding bifurcations of periodic orbits in the dry friction oscillator. The system of periodic orbits. The dry friction oscillator is a very good example of a nonsmooth system containing

  11. Dry Friction and Impact Dynamics in Railway Vehicles Dan Erik Petersen Mark Hoffmann

    E-Print Network [OSTI]

    Dry Friction and Impact Dynamics in Railway Vehicles Dan Erik Petersen Mark Hoffmann c973539 c Piotrowski. This model successfully takes into account damping due to dry friction in the suspension links due to dry friction. The wheelsets are constrained by guidance structures of the freight wagon

  12. Adhesion and Anisotropic Friction Enhancements of Angled Heterogeneous Micro-Fiber Arrays with

    E-Print Network [OSTI]

    Goldstein, Seth Copen

    in a synthetic dry angled fibrillar adhesive sample (spatula tip fiber sample). The direction dependent frictionAdhesion and Anisotropic Friction Enhancements of Angled Heterogeneous Micro-Fiber Arrays and spatula shaped tips via dipping. These fibers are characterized for adhesion and friction and compared

  13. LETTER doi:10.1038/nature13202 Classical shear cracks drive the onset of dry frictional

    E-Print Network [OSTI]

    Fineberg, Jay

    LETTER doi:10.1038/nature13202 Classical shear cracks drive the onset of dry frictional motion Ilya contactsdefiningafrictionalinterface3,4 . Therearea varietyofviews on how best to describe the onset of dry frictional motion the interface. We investigated the onset of dry frictional motion by per- forming simultaneous high

  14. Study of a transition in the qualitative behaviour of a simple oscillator with Coulomb friction

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    in the following way: when a system involving unilateral contact and dry friction is submitted to an oscillatingStudy of a transition in the qualitative behaviour of a simple oscillator with Coulomb friction. Keywords Coulomb friction, equilibrium states, mass-spring systems, nonsmooth dynamics. 1 Introduction

  15. An efficient scheme on wet/dry transitions for Shallow Water Equations with friction Christophe Berthona

    E-Print Network [OSTI]

    Coudière, Yves

    An efficient scheme on wet/dry transitions for Shallow Water Equations with friction Christophe discrepancy between both source terms comes from their relevance in dry regions. Indeed, the friction term the friction source terms in the shallow-water model. Such additional source terms are known to be very stiff

  16. Transition from Thermal to Athermal Friction under Cryogenic Conditions Xueying Zhao (),1

    E-Print Network [OSTI]

    Sawyer, Wallace

    the strong dependence of friction on temperature under cryogenic and dry sliding conditions in termsTransition from Thermal to Athermal Friction under Cryogenic Conditions Xueying Zhao (),1 Simon R manuscript received 3 April 2009; published 5 May 2009) Atomic scale frictional forces encountered

  17. Experimental study of friction noise of dry contact under light load

    E-Print Network [OSTI]

    Le-Bot, Alain

    Experimental study of friction noise of dry contact under light load A. Le Bot ­ H. Ben Abdelounis of friction noise radiated from the contact area of two sliding solids. The domain of interest is dry contact, that is the friction sound aris- ing when two dry and rough surfaces are rubbed on each other under light normal load

  18. Tribol Lett Thermal -Induced Wear Mechanisms of Sheet Nacre in Dry Friction

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Tribol Lett 1 Thermal - Induced Wear Mechanisms of Sheet Nacre in Dry Friction Philippe Stempfléa on the wear of sheet nacre by the assessment of the thermal component of the friction with a scanning thermal because the friction-induced thermal component is not sufficient for degrading the organic matrices

  19. Stick-slip friction and nucleation dynamics of ultrathin liquid films I. S. Aranson,1

    E-Print Network [OSTI]

    Hasty, Jeff

    yield stress leading to stick-slips similar to that in solid-on-solid dry friction processes5Stick-slip friction and nucleation dynamics of ultrathin liquid films I. S. Aranson,1 L. S'' of the confined fluid. This model successfully accounts for the observed phenomenology of friction in ultrathin

  20. Complex Non-Linear Modal Analysis for Mechanical Systems: Application to Turbomachinery Bladings With Friction

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    -conservative mechanical systems is proposed. In particular, dry-friction non-linearities are considered although degrees-of-freedom example featuring dry-friction illustrates the method and highlights the effects of a turbomachinery blade, with dry-friction interfaces is proposed. In the latter, an original framework

  1. A Concurrent Product-Development Approach for Friction-Stir Welded Vehicle-Underbody Structures

    E-Print Network [OSTI]

    Grujicic, Mica

    A Concurrent Product-Development Approach for Friction-Stir Welded Vehicle-Underbody Structures M technologies such as friction-stir welding (FSW) have to be employed. However, since FSW is a relatively new-survivable and ballistic threat-resistant military vehicles, friction-stir welding, process development 1. Introduction

  2. Computational Investigation of Hardness Evolution During Friction-Stir Welding of AA5083 and AA2139

    E-Print Network [OSTI]

    Grujicic, Mica

    Computational Investigation of Hardness Evolution During Friction-Stir Welding of AA5083 and AA2139 coupled thermo-mechanical finite-element analysis of the friction-stir welding (FSW) process developed, finite-element analysis, friction- stir welding, hardness prediction 1. Introduction Having a more mobile

  3. An accurate elasto-plastic frictional tangential forcedisplacement model for granular-flow

    E-Print Network [OSTI]

    Vu-Quoc, Loc

    An accurate elasto-plastic frictional tangential force­displacement model for granular for both elastic and plastic deformations together with interfacial friction occurring in collisions of spherical particles. This elasto-plastic frictional TFD model, with its force-driven version presented in [L

  4. Shakedown of coupled two-dimensional discrete frictional systems Young Ju Ahn a

    E-Print Network [OSTI]

    Daly, Samantha

    that Melan's theorem can be applied to discrete elastic systems governed by the Coulomb friction law only systems. & 2008 Elsevier Ltd. All rights reserved. 1. Introduction The classical Coulomb friction law with the Coulomb friction law. These parallels and experience with the solution of specific example problems have

  5. Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated Tropical Cyclone*

    E-Print Network [OSTI]

    Wang, Yuqing

    Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated is eventually dissipated due to surface friction. Since the energy production rate is a linear function while frictional dissipation rate balances the energy production rate near the radius of maximum wind (RMW

  6. Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated Tropical Cyclone

    E-Print Network [OSTI]

    Wang, Yuqing

    0 Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated is eventually dissipated due to surface friction. Since the energy production rate is a linear function while frictional dissipation rate balances the energy production rate near the radius of maximum wind (RMW

  7. A Nonsmooth Newton Solver for Capturing Exact Coulomb Friction in Fiber Assemblies

    E-Print Network [OSTI]

    A Nonsmooth Newton Solver for Capturing Exact Coulomb Friction in Fiber Assemblies FLORENCE in a stable way, and approximate Coulombs's friction law for making the problem tractable. In contrast- act Coulomb friction as a zero finding problem of a nonsmooth function. A semi-implicit time

  8. Dependence of friction on roughness, velocity, and temperature Martin Dub,2

    E-Print Network [OSTI]

    Grant, Martin

    - faces were discovered long ago by Da Vinci, Amonton, and Coulomb. They found that friction is i, and friction at the macroscopic level is now well understood, for both dry rough 3 and lubricated surfaces 4Dependence of friction on roughness, velocity, and temperature Yi Sang,1 Martin Dubé,2 and Martin

  9. About contacts of adhesive, elasto-plastic, frictional powders Stefan Luding

    E-Print Network [OSTI]

    Luding, Stefan

    , for more details see [4; 8]. Adhesive Contact Model For fine dry particles [9], not only frictionAbout contacts of adhesive, elasto-plastic, frictional powders Stefan Luding Multi Scale Mechanics). The contact mechanics used involves elasto-plastic, viscous, frictional, and torque contributions. From

  10. Experimental evidence of flutter and divergence instabilities induced by dry friction

    E-Print Network [OSTI]

    Bigoni, Davide

    Experimental evidence of flutter and divergence instabilities induced by dry friction Davide Bigoni structures with Coulomb friction, but no direct experimental evidence has ever been provided. Moreover Coulomb friction and how this, in full agreement with the theory, can induce a blowing-up vibrational

  11. A Hybrid Iterative Solver for Robustly Capturing Coulomb Friction in Hair Dynamics

    E-Print Network [OSTI]

    A Hybrid Iterative Solver for Robustly Capturing Coulomb Friction in Hair Dynamics Gilles Daviet-slip instabilities. See the accompanying video for the full animations. Abstract Dry friction between hair fibers a hybrid strategy that combines a new zero-finding formulation of (exact) Coulomb friction together

  12. Frictional powders: Ratcheting under periodic strain in 3D , C. T. David2

    E-Print Network [OSTI]

    Luding, Stefan

    and Coulomb friction. In the simplest case visco-elastic rules can be imposed at each contact, differentFrictional powders: Ratcheting under periodic strain in 3D S. Luding1 , C. T. David2 , R. Garcia of friction leads to a transition from ratcheting to shake-down, i.e., the accumulation of strain stops

  13. Heat collector

    DOE Patents [OSTI]

    Merrigan, Michael A. (Santa Cruz, NM)

    1984-01-01T23:59:59.000Z

    A heat collector and method suitable for efficiently and cheaply collecting solar and other thermal energy are provided. The collector employs a heat pipe in a gravity-assist mode and is not evacuated. The collector has many advantages, some of which include ease of assembly, reduced structural stresses on the heat pipe enclosure, and a low total materials cost requirement. Natural convective forces drive the collector, which after startup operates entirely passively due in part to differences in molecular weights of gaseous components within the collector.

  14. Heat collector

    DOE Patents [OSTI]

    Merrigan, M.A.

    1981-06-29T23:59:59.000Z

    A heat collector and method suitable for efficiently and cheaply collecting solar and other thermal energy are provided. The collector employs a heat pipe in a gravity-assist mode and is not evacuated. The collector has many advantages, some of which include ease of assembly, reduced structural stresses on the heat pipe enclosure, and a low total materials cost requirement. Natural convective forces drive the collector, which after startup operates entirely passively due in part to differences in molecular weights of gaseous components within the collector.

  15. Finite quantum dissipation: the challenge of obtaining specific heat

    E-Print Network [OSTI]

    Hänggi, Peter; Talkner, Peter

    2008-01-01T23:59:59.000Z

    We consider a free particle coupled with finite strength to a bath and investigate the evaluation of its specific heat. A harmonic oscillator bath of Drude type with cutoff frequency omega_D is employed to model an ohmic friction force with dissipation strength gamma. Two scenarios for obtaining specific heat are presented. The first one uses the measurement of the kinetic energy of the free particle while the second one is based on the reduced partition function. Both descriptions yield results which are consistent with the Third Law of thermodynamics. Nevertheless, the two methods produce different results that disagree even in their leading quantum corrections at high temperatures. We also consider the regime where the cutoff frequency is smaller than the friction strength, i.e. omega_D1.

  16. Smoluchowski-Kramers approximation in the case of variable friction

    E-Print Network [OSTI]

    Mark Freidlin; Wenqing Hu

    2012-03-03T23:59:59.000Z

    We consider the small mass asymptotics (Smoluchowski-Kramers approximation) for the Langevin equation with a variable friction coefficient. The limit of the solution in the classical sense does not exist in this case. We study a modification of the Smoluchowski-Kramers approximation. Some applications of the Smoluchowski-Kramers approximation to problems with fast oscillating or discontinuous coefficients are considered.

  17. Casimir Friction Force and Energy Dissipation for Moving Harmonic Oscillators

    E-Print Network [OSTI]

    Johan S. Høye; Iver Brevik

    2010-09-15T23:59:59.000Z

    The Casimir friction problem for a pair of dielectric particles in relative motion is analyzed, utilizing a microscopic model in which we start from statistical mechanics for harmonically oscillating particles at finite temperature moving nonrelativistically with constant velocity. The use of statistical mechanics in this context has in our opinion some definite advantages, in comparison with the more conventional quantum electrodynamic description of media that involves the use of a refractive index. The statistical-mechanical description is physical and direct, and the oscillator model, in spite of its simplicity, is nevertheless able to elucidate the essentials of the Casimir friction. As is known, there are diverging opinions about this kind of friction in the literature. Our treatment elaborates upon, and extends, an earlier theory presented by us back in 1992. There we found a finite friction force at any finite temperature, whereas at zero temperature the model led to a zero force. As an additional development in the present paper we evaluate the energy dissipation making use of an exponential cutoff truncating the relative motion of the oscillators. For the dissipation we also establish a general expression that is not limited to the simple oscillator model.

  18. Friction stir method for forming structures and materials

    DOE Patents [OSTI]

    Feng, Zhili (Knoxville, TN); David, Stan A. (Knoxville, TN); Frederick, David Alan (Harriman, TN)

    2011-11-22T23:59:59.000Z

    Processes for forming an enhanced material or structure are disclosed. The structure typically includes a preform that has a first common surface and a recess below the first common surface. A filler is added to the recess and seams are friction stir welded, and materials may be stir mixed.

  19. Sliding Friction with Polymer Brushes Rafael Tadmor,* Joanna Janik,

    E-Print Network [OSTI]

    Klein, Jacob

    across the polymer layers decays logarithmically with time, consistent with the relaxation of a network on the sliding velocity, an effect attributed to a velocity-dependent interpenetration of the opposing polymerSliding Friction with Polymer Brushes Rafael Tadmor,* Joanna Janik, and Jacob Klein Department

  20. TBM tunnel friction values for the Grizzly Powerhouse Project

    SciTech Connect (OSTI)

    Stutsman, R.D. [Ensign & Buckley Consulting Engineers, Larkspur, CA (United States); Rothfuss, B.D. [Pacific Gas and Electric Co., San Francisco, CA (United States)

    1995-12-31T23:59:59.000Z

    Tunnel boring machine (TBM) driven water conveyance tunnels are becoming increasingly more common. Despite advances in tunnel engineering and construction technology, hydraulic performance data for TBM driven tunnels remains relatively unavailable. At the Grizzly Powerhouse Project, the TBM driven water conveyance tunnel was designed using friction coefficients developed from a previous PG&E project. A range of coefficients were selected to bound the possible hydraulic performance variations of the water conveyance system. These friction coefficients, along with the water conveyance systems characteristics, and expected turbine characteristics, were used in a hydraulic transient analysis to determine the expected system pressure fluctuations, and surge chamber performance. During startup test data, these performance characteristics were measured to allow comparison to the original design assumptions. During construction of the tunnel, plaster casts were made of the actual excavated tunnel unlined and fiber reinforced shotcrete lined surfaces. These castings were used to measure absolute roughness of the surfaces so that a friction coefficient could be developed using the Moody diagram and compare them against the design values. This paper compares the assumed frictional coefficient with computed coefficients from headlosses measured during startup testing, and plaster cast measurement calculations. In addition, a comparison of coefficients will be presented for an other TBM driven water conveyance tunnel constructed in the 1980`s.

  1. Lateral position detection and control for friction stir systems

    DOE Patents [OSTI]

    Fleming, Paul (Boulder, CO); Lammlein, David (Houston, TX); Cook, George E. (Brentwood, TN); Wilkes, Don Mitchell (Nashville, TN); Strauss, Alvin M. (Nashville, TN); Delapp, David (Ashland City, TN); Hartman, Daniel A. (Santa Fe, NM)

    2010-12-14T23:59:59.000Z

    A friction stir system for processing at least a first workpiece includes a spindle actuator coupled to a rotary tool comprising a rotating member for contacting and processing the first workpiece. A detection system is provided for obtaining information related to a lateral alignment of the rotating member. The detection system comprises at least one sensor for measuring a force experienced by the rotary tool or a parameter related to the force experienced by the rotary tool during processing, wherein the sensor provides sensor signals. A signal processing system is coupled to receive and analyze the sensor signals and determine a lateral alignment of the rotating member relative to a selected lateral position, a selected path, or a direction to decrease a lateral distance relative to the selected lateral position or selected path. In one embodiment, the friction stir system can be embodied as a closed loop tracking system, such as a robot-based tracked friction stir welding (FSW) or friction stir processing (FSP) system.

  2. ccsd00000893 Sliding Friction at a Rubber/Brush Interface

    E-Print Network [OSTI]

    ccsd­00000893 (version 1) : 28 Nov 2003 Sliding Friction at a Rubber/Brush Interface Lionel Bureau(dimethylsiloxane) (PDMS) rubber network sliding, at low velocity, on a substrate on which PDMS chains are end-tethered. We studied the behaviour of such rubber/brush interfaces at high sliding velocities and showed

  3. Brownian ratchet in a thermal bath driven by Coulomb friction

    E-Print Network [OSTI]

    A. Gnoli; A. Petri; F. Dalton; G. Gradenigo; G. Pontuale; A. Sarracino; A. Puglisi

    2013-01-14T23:59:59.000Z

    The rectification of unbiased fluctuations, also known as the ratchet effect, is normally obtained under statistical non-equilibrium conditions. Here we propose a new ratchet mechanism where a thermal bath solicits the random rotation of an asymmetric wheel, which is also subject to Coulomb friction due to solid-on-solid contacts. Numerical simulations and analytical calculations demonstrate a net drift induced by friction. If the thermal bath is replaced by a granular gas, the well known granular ratchet effect also intervenes, becoming dominant at high collision rates. For our chosen wheel shape the granular effect acts in the opposite direction with respect to the friction-induced torque, resulting in the inversion of the ratchet direction as the collision rate increases. We have realized a new granular ratchet experiment where both these ratchet effects are observed, as well as the predicted inversion at their crossover. Our discovery paves the way to the realization of micro and sub-micrometer Brownian motors in an equilibrium fluid, based purely upon nano-friction.

  4. The influence of internal friction on rotordynamic instability 

    E-Print Network [OSTI]

    Srinivasan, Anand

    2004-09-30T23:59:59.000Z

    Internal friction has been known to be a cause of whirl instability in built-up rotors since the early 1900's. This internal damping tends to make the rotor whirl at shaft speeds greater than a critical speed, the whirl speed usually being equal...

  5. TEMPORARILY ALLOYING TITANIUM TO FACILITATE FRICTION STIR WELDING

    SciTech Connect (OSTI)

    Hovanski, Yuri

    2009-05-06T23:59:59.000Z

    While historically hydrogen has been considered an impurity in titanium, when used as a temporary alloying agent it promotes beneficial changes to material properties that increase the hot-workability of the metal. This technique known as thermohydrogen processing was used to temporarily alloy hydrogen with commercially pure titanium sheet as a means of facilitating the friction stir welding process. Specific alloying parameters were developed to increase the overall hydrogen content of the titanium sheet ranging from commercially pure to 30 atomic percent. Each sheet was evaluated to determine the effect of the hydrogen content on process loads and tool deformation during the plunge phase of the friction stir welding process. Two materials, H-13 tool steel and pure tungsten, were used to fabricate friction stir welding tools that were plunged into each of the thermohydrogen processed titanium sheets. Tool wear was characterized and variations in machine loads were quantified for each tool material and weld metal combination. Thermohydrogen processing was shown to beneficially lower plunge forces and stabilize machine torques at specific hydrogen concentrations. The resulting effects of hydrogen addition to titanium metal undergoing the friction stir welding process are compared with modifications in titanium properties documented in modern literature. Such comparative analysis is used to explain the variance in resulting process loads as a function of the initial hydrogen concentration of the titanium.

  6. Wetting and friction on superoleophobic surfaces March 20, 2009

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    then focus on their friction properties, and es- tablish an important condition for their use as super-lubricating,15­18 . Similar surfaces can be produced to repel oil, but repelling both oil and water with the same surface is a true challenge since surfaces that repel water are usu- ally attracting oils. The recently introduced

  7. Modeling of friction-induced deformation and microstructures.

    SciTech Connect (OSTI)

    Michael, Joseph Richard; Prasad, Somuri V.; Jungk, John Michael; Cordill, Megan J. (University of Minnesota); Bammann, Douglas J.; Battaile, Corbett Chandler; Moody, Neville Reid; Majumdar, Bhaskar Sinha (New Mexico Institure of Mining and Technology)

    2006-12-01T23:59:59.000Z

    Frictional contact results in surface and subsurface damage that could influence the performance, aging, and reliability of moving mechanical assemblies. Changes in surface roughness, hardness, grain size and texture often occur during the initial run-in period, resulting in the evolution of subsurface layers with characteristic microstructural features that are different from those of the bulk. The objective of this LDRD funded research was to model friction-induced microstructures. In order to accomplish this objective, novel experimental techniques were developed to make friction measurements on single crystal surfaces along specific crystallographic surfaces. Focused ion beam techniques were used to prepare cross-sections of wear scars, and electron backscattered diffraction (EBSD) and TEM to understand the deformation, orientation changes, and recrystallization that are associated with sliding wear. The extent of subsurface deformation and the coefficient of friction were strongly dependent on the crystal orientation. These experimental observations and insights were used to develop and validate phenomenological models. A phenomenological model was developed to elucidate the relationships between deformation, microstructure formation, and friction during wear. The contact mechanics problem was described by well-known mathematical solutions for the stresses during sliding friction. Crystal plasticity theory was used to describe the evolution of dislocation content in the worn material, which in turn provided an estimate of the characteristic microstructural feature size as a function of the imposed strain. An analysis of grain boundary sliding in ultra-fine-grained material provided a mechanism for lubrication, and model predictions of the contribution of grain boundary sliding (relative to plastic deformation) to lubrication were in good qualitative agreement with experimental evidence. A nanomechanics-based approach has been developed for characterizing the mechanical response of wear surfaces. Coatings are often required to mitigate friction and wear. Amongst other factors, plastic deformation of the substrate determines the coating-substrate interface reliability. Finite element modeling has been applied to predict the plastic deformation for the specific case of diamond-like carbon (DLC) coated Ni alloy substrates.

  8. Confined flow of suspensions modeled by a frictional rheology

    E-Print Network [OSTI]

    Brice Lecampion; Dmitry I. Garagash

    2014-09-19T23:59:59.000Z

    We investigate in detail the problem of confined pressure-driven laminar flow of neutrally buoyant non-Brownian suspensions using a frictional rheology based on the recent proposal of Boyer et al., 2011. The friction coefficient and solid volume fraction are taken as functions of the dimensionless viscous number I defined as the ratio between the fluid shear stress and the particle normal stress. We clarify the contributions of the contact and hydrodynamic interactions on the evolution of the friction coefficient between the dilute and dense regimes reducing the phenomenological constitutive description to three physical parameters. We also propose an extension of this constitutive law from the flowing regime to the fully jammed state. We obtain an analytical solution of the fully-developed flow in channel and pipe for the frictional suspension rheology. The result can be transposed to dry granular flow upon appropriate redefinition of the dimensionless number I. The predictions are in excellent agreement with available experimental results, when using the values of the constitutive parameters obtained independently from stress-controlled rheological measurements. In particular, the frictional rheology correctly predicts the transition from Poiseuille to plug flow and the associated particles migration with the increase of the entrance solid volume fraction. We numerically solve for the axial development of the flow from the inlet of the channel/pipe toward the fully-developed state. The available experimental data are in good agreement with our predictions. The solution of the axial development of the flow provides a quantitative estimation of the entrance length effect in pipe for suspensions. A analytical expression for development length is shown to encapsulate the numerical solution in the entire range of flow conditions from dilute to dense.

  9. Variable enstrophy flux and energy spectrum in two-dimensional turbulence with Ekman friction

    E-Print Network [OSTI]

    Mahendra K. Verma

    2012-03-23T23:59:59.000Z

    Experiments and numerical simulations reveal that in the forward cascade regime, the energy spectrum of two-dimensional turbulence with Ekman friction deviates from Kraichnan's prediction of $k^{-3}$ power spectrum. In this letter we explain this observation using an analytic model based on variable enstrophy flux arising due to Ekman friction. We derive an expression for the enstrophy flux which exhibits a logarithmic dependence in the inertial range for the Ekman-friction dominated flows. The energy spectrum obtained using this enstrophy flux shows a power law scaling for large Reynolds number and small Ekman friction, but has an exponential behaviour for large Ekman friction and relatively small Reynolds number.

  10. Transforms for prediction residuals in video coding

    E-Print Network [OSTI]

    Kam??l?, Fatih

    2010-01-01T23:59:59.000Z

    Typically the same transform, the 2-D Discrete Cosine Transform (DCT), is used to compress both image intensities in image coding and prediction residuals in video coding. Major prediction residuals include the motion ...

  11. All-glass vacuum tube collector heat transfer model used in forced-circulation solar water heating system

    SciTech Connect (OSTI)

    Li, Zhiyong; Chen, Chao; Luo, Hailiang; Zhang, Ye; Xue, Yaning [College of Architecture and Civil Engineering, Beijing University of Technology, Beijing (China)

    2010-08-15T23:59:59.000Z

    The aim of this paper is to establish the heat transfer model of all-glass vacuum tube collector used in forced-circulation solar water heating system. In this model, the simplified heat transfer of collector is composed of the natural convection in single glass tube and forced flow in manifold header. Thus the heat balance equation of water in single tube and the heat balance equation of water in manifold header have been established. The flow equation is also built by analyzing the friction and buoyancy in tube. Through solved these equations the relationship between the collector average temperature, the outlet temperature and natural convection flow rate have been obtained. From this relationship and energy balance equation of collector, the collector outlet temperature can be calculated. The validated experiments of this model were carried out in winter of Beijing. (author)

  12. Heating System Specification Specification of Heating System

    E-Print Network [OSTI]

    Day, Nancy

    Appendix A Heating System Specification /* Specification of Heating System (loosely based */ requestHeat : Room ­? bool; 306 #12; APPENDIX A. HEATING SYSTEM SPECIFICATION 307 /* user inputs */ livingPattern : Room ­? behaviour; setTemp : Room ­? num; heatSwitchOn, heatSwitchOff, userReset : simple

  13. Residual Stresses in Weldments by Neutron Diffraction

    E-Print Network [OSTI]

    Bandara, Arosha

    Rectors and Pressurised Water Reactors Source of Problem · Internal Residual Stress · Material propertiesResidual Stresses in Weldments by Neutron Diffraction Shanmukha Rao M, Jon James, Shirley Northover of Residual Stress inside Materials Material: 3 Pass Weld Austenitic Stainless Steel Working Principle

  14. A climatic heat budget study of the Gulf of Mexico

    E-Print Network [OSTI]

    Etter, Paul Courtney

    1975-01-01T23:59:59.000Z

    of heat storage (G ) is calo~ lated apparently for the first time directly by use of available bathythermograph (BT) data. Heat flux di rergence due to currents (0 ), calculated as a residual in the heat budget equation, is small. The monthly mean... surface ( CA) . . 16 C. The rate of heat storage (Q ) 32 0. Solution of the oceanic heat budget 39 Comparison with Earlier Studies Summary 56 References Appendix A App ndix 3 Vita 61 79 vi LIST OF TA. '3LES Table Page Number of observations...

  15. Microstructural characterization in dissimilar friction stir welding between 304 stainless steel and st37 steel

    SciTech Connect (OSTI)

    Jafarzadegan, M. [Department of Materials Eng., Tarbiat Modares University, P.O. Box: 14115-143, Tehran (Iran, Islamic Republic of) [Department of Materials Eng., Tarbiat Modares University, P.O. Box: 14115-143, Tehran (Iran, Islamic Republic of); State Key Laboratory of Advanced Welding Production Technology, School of Materials Science and Eng., Harbin Institute of Technology, P.O. Box: 150001, Harbin (China); Feng, A.H. [State Key Laboratory of Advanced Welding Production Technology, School of Materials Science and Eng., Harbin Institute of Technology, P.O. Box: 150001, Harbin (China)] [State Key Laboratory of Advanced Welding Production Technology, School of Materials Science and Eng., Harbin Institute of Technology, P.O. Box: 150001, Harbin (China); Abdollah-zadeh, A., E-mail: zadeh@modares.ac.ir [Department of Materials Eng., Tarbiat Modares University, P.O. Box: 14115-143, Tehran (Iran, Islamic Republic of); Saeid, T. [Advanced Materials Research Center, Sahand University of Technology, P.O. Box: 51335-1996, Tabriz (Iran, Islamic Republic of)] [Advanced Materials Research Center, Sahand University of Technology, P.O. Box: 51335-1996, Tabriz (Iran, Islamic Republic of); Shen, J. [State Key Laboratory of Advanced Welding Production Technology, School of Materials Science and Eng., Harbin Institute of Technology, P.O. Box: 150001, Harbin (China)] [State Key Laboratory of Advanced Welding Production Technology, School of Materials Science and Eng., Harbin Institute of Technology, P.O. Box: 150001, Harbin (China); Assadi, H. [Department of Materials Eng., Tarbiat Modares University, P.O. Box: 14115-143, Tehran (Iran, Islamic Republic of)] [Department of Materials Eng., Tarbiat Modares University, P.O. Box: 14115-143, Tehran (Iran, Islamic Republic of)

    2012-12-15T23:59:59.000Z

    In the present study, 3 mm-thick plates of 304 stainless steel and st37 steel were welded together by friction stir welding at a welding speed of 50 mm/min and tool rotational speed of 400 and 800 rpm. X-ray diffraction test was carried out to study the phases which might be formed in the welds. Metallographic examinations, and tensile and microhardness tests were used to analyze the microstructure and mechanical properties of the joint. Four different zones were found in the weld area except the base metals. In the stir zone of the 304 stainless steel, a refined grain structure with some features of dynamic recrystallization was evidenced. A thermomechanically-affected zone was characterized on the 304 steel side with features of dynamic recovery. In the other side of the stir zone, the hot deformation of the st37 steel in the austenite region produced small austenite grains and these grains transformed to fine ferrite and pearlite and some products of displacive transformations such as Widmanstatten ferrite and martensite by cooling the material after friction stir welding. The heat-affected zone in the st37 steel side showed partially and fully refined microstructures like fusion welding processes. The recrystallization in the 304 steel and the transformations in the st37 steel enhanced the hardness of the weld area and therefore, improved the tensile properties of the joint. - Highlights: Black-Right-Pointing-Pointer FSW produced sound welds between st37 low carbon steel and 304 stainless steel. Black-Right-Pointing-Pointer The SZ of the st37 steel contained some products of allotropic transformation. Black-Right-Pointing-Pointer The material in the SZ of the 304 steel showed features of dynamic recrystallization. Black-Right-Pointing-Pointer The finer microstructure in the SZ increased the hardness and tensile strength.

  16. nature physics | VOL 6 | MARCH 2010 | www.nature.com/naturephysics 155 How do you solve a problem like friction?

    E-Print Network [OSTI]

    Loss, Daniel

    a problem like friction? I learned to respect friction, as a phenomenon with many nuances, when I friction between the ball and floor, work out, first, how far the ball goes before it is rolling. The first part, I quickly demonstrated, is easy. Assuming the force of sliding friction is independent

  17. Texture-Induced Modulations of Friction Force: The Fingerprint Effect E. Wandersman, R. Candelier, G. Debregeas, and A. Prevost*

    E-Print Network [OSTI]

    Debrégeas, Georges

    2011) Modulations of the friction force in dry solid friction are usually attributed to macroscopicTexture-Induced Modulations of Friction Force: The Fingerprint Effect E. Wandersman, R. Candelier's main ingredient is the nonlinearity of the friction law. Since such nonlinearity is ubiquitous for soft

  18. Heat transfer in the trailing edge cooling channels of turbine blades

    E-Print Network [OSTI]

    Kumaran, T. K.

    1989-01-01T23:59:59.000Z

    Foundation and from the funded research contract (RF5810) through Dr. Han. NOMENCLATURE A area of heat transfer in the pin fin channel AI, area of heat transfer in the long ejection segments Az cross-sectional area, of trailing edge ejection holes A..., ?minimum flow cross-sectional area in the pin fin channel C'~ discharge coefficient Cp specific heat of air 1 diameter of trailing edge ejection holes D diameter of pins f overall friction factor h?heat transfer coefficient in the n th segment...

  19. Microcomputer analysis of regenerative heat exchangers for oscillating flow

    SciTech Connect (OSTI)

    Hutchinson, R.A.; Lyke, S.E.

    1987-03-01T23:59:59.000Z

    Regenerative heat exchangers for use in oscillating flows such as those occurring in Stirling engines present considerable analytical problems to the thermal engineer. A simplified finite element analysis has been implemented in a spreadsheet, providing improved access to analytical assumptions and allowing parametric analysis of current heat transfer data. In addition, an irreversibility analysis has been implemented using the thermal and friction results in the spreadsheet. It is suited for evaluation and insights into loss tradeoffs inside operating regenerators, to suggest new regenerator design concepts, and to focus experimental work. 22 refs., 13 figs.

  20. Feasibility of natural circulation heat transport in the ENHS.

    SciTech Connect (OSTI)

    Sienicki, J.J.

    2002-02-14T23:59:59.000Z

    An analysis has been carried out of natural circulation thermal hydraulics in both the primary and intermediate circuits of the Encapsulated Nuclear Heat Source (ENHS). It is established that natural circulation enhanced by gas injection into the primary coolant above the core, or the intermediate coolant above the heat exchange zone, is effective in transporting the nominal core power to the steam generators without the attainment of excessive system temperatures. Uncertainties in thermophysical properties and wall friction have a relatively small effect upon the calculated best estimate primary and intermediate coolant system temperature rises.

  1. Feasibility of Natural Circulation Heat Transport in the ENHS

    SciTech Connect (OSTI)

    Sienicki, James J. [Argonne National Laboratory, 9700 S. Cass Avenue Argonne, IL 60439 (United States)

    2002-07-01T23:59:59.000Z

    An analysis has been carried out of natural circulation thermal hydraulics in both the primary and intermediate circuits of the Encapsulated Nuclear Heat Source (ENHS). It is established that natural circulation enhanced by gas injection into the primary coolant above the core, or the intermediate coolant above the heat exchange zone, is effective in transporting the nominal core power to the steam generators without the attainment of excessive system temperatures. Uncertainties in thermophysical properties and wall friction have a relatively small effect upon the calculated best estimate primary and intermediate coolant system temperature rises. (authors)

  2. The development of design factors for heat-strengthened and tempered glass based on the glass failure prediction model

    E-Print Network [OSTI]

    Oakes, Timothy Andrew

    1991-01-01T23:59:59.000Z

    of the interior. According to ASTM, the residual surface compression of tempered glass is defined to have a value of 10, 000 psi (68. 95 MPa) while heat-strengthened glass has residual compressive stresses greater than 3, 500 psi (24. 13 MPa) but less than 10..., 000 psi (68. 95 MPa) (ASTM, 1989). These residual surface compressive stresses must be overcome by mechanical stresses before the glass surfaces experience tension. Hence heat-strengthened and tempered glass are considerably stronger than annealed...

  3. Rack-and-pinion effects in molecular rolling friction

    E-Print Network [OSTI]

    Oleg M. Braun; Erio Tosatti

    2008-09-05T23:59:59.000Z

    Rolling lubrication with spherical molecules working as 'nanobearings' has failed experimentally so far, without a full understanding of the physics involved and of the reasons why. Past model simulations and common sense have shown that molecules can only roll when they are not too closely packed to jam. The same type of model simulations now shows in addition that molecular rolling friction can develop deep minima once the molecule's peripheral 'pitch' can match the substrate periodicity, much as ordinary cogwheels do in a rack-and-pinion system. When the pinion-rack matching is bad, the driven molecular rolling becomes discontinuous and noisy, whence energy is dissipated and friction is large. This suggests experiments to be conducted by varying the rack-and-pinion matching. That could be pursued not only by changing molecules and substrates, but also by applying different sliding directions within the same system, or by applying pressure, to change the effective matching.

  4. Friction and the oscillatory motion of granular flows

    E-Print Network [OSTI]

    Lydie Staron

    2012-11-26T23:59:59.000Z

    This contribution reports on numerical simulations of 2D granular flows on erodible beds. The broad aim is to investigate whether simple flows of model granular matter exhibits spontaneous oscillatory motion in generic flow conditions, and in this case, whether the frictional properties of the contacts between grains may affect the existence or the characteristics of this oscillatory motion. The analysis of different series of simulations show that the flow develops an oscillatory motion with a well-defined frequency which increases like the inverse of the velocity's square root. We show that the oscillation is essentially a surface phenomena. The amplitude of the oscillation is higher for lower volume fractions, and can thus be related to the flow velocity and grains friction properties. The study of the influence of the periodic geometry of the simulation cell shows no significant effect. These results are discussed in relation to sonic sands.

  5. Micro-beam friction liner and method of transferring energy

    DOE Patents [OSTI]

    Mentesana, Charles (Leawood, KS)

    2007-07-17T23:59:59.000Z

    A micro-beam friction liner adapted to increase performance and efficiency and reduce wear in a piezoelectric motor or actuator or other device using a traveling or standing wave to transfer energy in the form of torque and momentum. The micro-beam friction liner comprises a dense array of micro-beam projections having first ends fixed relative to a rotor and second ends projecting substantially toward a plurality of teeth of a stator, wherein the micro-beam projections are compressed and bent during piezoelectric movement of the stator teeth, thereby storing the energy, and then react against the stator teeth to convert the stored energy stored to rotational energy in the rotor.

  6. Friction Factor Measurements in an Equally Spaced Triangular Tube Array

    SciTech Connect (OSTI)

    Vassallo P, Symolon P

    2007-03-19T23:59:59.000Z

    Friction factor data for adiabatic cross-flow of water in a staggered tube array was obtained over a Reynolds number range (based on hydraulic diameter and gap velocity) of about 10,000 to 250,000. The tubes were 12.7mm (0.5 inch) outer diameter, in a uniformly spaced triangular arrangement with a pitch-to-diameter ratio of 1.5. The friction factor was compared to several literature correlations, and was found to be best matched by the Idelchik correlation. Other correlations were found to vary significantly from the test data. Based on the test data, a new correlation is proposed for this tube bundle geometry which covers the entire Reynolds number range tested.

  7. Quantum Vacuum Friction in Highly Magnetized Neutron Stars

    E-Print Network [OSTI]

    Arnaud Dupays; Carlo Rizzo; Dimitar Bakalov; Giovanni F. Bignami

    2008-04-25T23:59:59.000Z

    In this letter we calculate the energy loss of highly magnetized neutron star due to friction with quantum vacuum, namely Quantum Vacuum Friction (QVF). Taking into account one-loop corrections in the effective Heisenberg-Euler Lagrangian of the light-light interaction, we derive an analytic expression for QVF allowing us to consider magnetic field at the surface of the star as high as $10^{11} $T. In the case of magnetars with high magnetic field above the QED critical field, we show that the energy loss by QVF dominates the energy loss process. This has important consequences, in particular on the inferred value of the magnetic field. This also indicates the need for independent measurements of magnetic field, energy loss rate, and of the braking index to fully characterize magnetars.

  8. Process to recycle shredder residue

    DOE Patents [OSTI]

    Jody, Bassam J. (Chicago, IL); Daniels, Edward J. (Oak Lawn, IL); Bonsignore, Patrick V. (Channahon, IL)

    2001-01-01T23:59:59.000Z

    A system and process for recycling shredder residue, in which separating any polyurethane foam materials are first separated. Then separate a fines fraction of less than about 1/4 inch leaving a plastics-rich fraction. Thereafter, the plastics rich fraction is sequentially contacted with a series of solvents beginning with one or more of hexane or an alcohol to remove automotive fluids; acetone to remove ABS; one or more of EDC, THF or a ketone having a boiling point of not greater than about 125.degree. C. to remove PVC; and one or more of xylene or toluene to remove polypropylene and polyethylene. The solvents are recovered and recycled.

  9. Does hydrologic circulation mask frictional heat on faults after large earthquakes?

    E-Print Network [OSTI]

    Fulton, Patrick M.; Harris, Robert N.; Saffer, Demian M.; Brodsky, Emily E.

    2010-01-01T23:59:59.000Z

    temper- ature effect of drilling a well in Arctic Alaska,deep boreholes, drilling fluids are well below the ambient

  10. Does hydrologic circulation mask frictional heat on faults after large earthquakes?

    E-Print Network [OSTI]

    Fulton, Patrick M.; Harris, Robert N.; Saffer, Demian M.; Brodsky, Emily E.

    2010-01-01T23:59:59.000Z

    thermal physical rock properties. Transient fluid flow isin thermal physical rock properties such as thermal5.2. Thermal Physical Rock Properties [ 24 ] For conductive

  11. Solid Friction from stick-slip to pinning and aging

    E-Print Network [OSTI]

    Tristan Baumberger; Christiane Caroli

    2005-06-24T23:59:59.000Z

    We review the present state of understanding of solid friction at low velocities and for systems with negligibly small wear effects. We first analyze in detail the behavior of friction at interfaces between wacroscopic hard rough solids, whose main dynamical features are well described by the Rice-Ruina rate and state dependent constitutive law. We show that it results from two combined effects : (i) the threshold rheology of nanometer-thick junctions jammed under confinement into a soft glassy structure (ii) geometric aging, i.e. slow growth of the real arrea of contact via asperity creep interrupted by sliding. Closer analysis leads to identifying a second aging-rejuvenation process, at work within the junctions themselves. We compare the effects of structural aging at such multicontact, very highly confined, interfaces with those met under different confinement levels, namely boundary lubricated contacts and extended adhesive interfaces involving soft materials (hydrogels, elastomers). This leads us to propose a classification of frictional junctions in terms of the relative importance of jamming and adsoprtion-induced metastability.

  12. Hydrodynamics of rapidly rotating superfluid neutron stars with mutual friction

    E-Print Network [OSTI]

    A. Passamonti; N. Andersson

    2010-04-26T23:59:59.000Z

    We study time evolutions of superfluid neutron stars, focussing on the nature of the oscillation spectrum, the effect of mutual friction force on the oscillations and the hydrodynamical spin-up phase of pulsar glitches. We linearise the dynamical equations of a Newtonian two-fluid model for rapidly rotating backgrounds. In the axisymmetric equilibrium configurations, the two fluid components corotate and are in beta-equilibrium. We use analytical equations of state that generate stratified and non-stratified stellar models, which enable us to study the coupling between the dynamical degrees of freedom of the system. By means of time evolutions of the linearised dynamical equations, we determine the spectrum of axisymmetric and non-axisymmetric oscillation modes, accounting for the contribution of the gravitational potential perturbations, i.e. without adopting the Cowling approximation. We study the mutual friction damping of the superfluid oscillations and consider the effects of the non-dissipative part of the mutual friction force on the mode frequencies. We also provide technical details and relevant tests for the hydrodynamical model of pulsar glitches discussed by Sidery, Passamonti and Andersson (2010). In particular, we describe the method used to generate the initial data that mimic the pre-glitch state, and derive the equations that are used to extract the gravitational-wave signal.

  13. Residual stress in laser welded dissimilar steel tube-to-tube joints

    SciTech Connect (OSTI)

    Sun, Zheng (Technical Research Centre of Finland, Espoo (Finland). Lab. of Production Engineering)

    1993-09-01T23:59:59.000Z

    Austenitic-ferritic dissimilar steel joints are widely used in power generation systems. Their utilization has proved to be efficient in terms of satisfactory properties and the economics. These types of joints have usually been produced using conventional welding processes, such as tungsten inert gas (TIG) welding. With the rapid development of high power lasers, laser welding has received considerable attention. Laser welding offers many advantages over conventional welding processes, e.g. low heat input, small heat-affected zone (HAZ), small distortion, and welding in an exact and reproducible manner. Residual stress distribution in laser welds may also differ from those made by conventional welding processes due to its special features. Residual stress, particularly tensile residual stress in the weld, can be very important factor in controlling the quality and service life of the welded structure. The formation of tensile residual stress in the weld may result in the initiation of fatigue cracking, stress corrosion cracking or other types of fractures. It is useful, therefore, to understand the distribution of residual stress in austenitic-ferritic laser welds, and thus evaluate the quality of the joints. Although residual stress distribution in the welded joints has been extensively investigated, little data are available for the residual stress distribution in laser welds. The aim of the work was to examine residual stress distribution along laser welds of dissimilar steel tube-to-tube joints, which were made by both autogeneous welding and welding with filler wire. The results were also compared with the joints made by plasma arc and TIG welding.

  14. An upgraded heat transfer fluid eliminates odors and leaks

    SciTech Connect (OSTI)

    NONE

    1995-10-01T23:59:59.000Z

    At Morton, persistent leakage of an aromatics-based heat transfer fluid left its mark--a black, oxidized residue at flange and valve locations. By switching to a high-purity fluid from a paraffinic hydrocarbon base stock, the firm eliminated odors and sticky residue, and improved heat transfer. After four years of operation with the paraffinic heat transfer fluid, Morton continues to have no odor problems and virtually no flange or packing leakage. As an added bonus, the heat transfer coefficient of the new fluid allows Morton to operate the systems 10--15 F cooler than when the company used the traditional, aromatic fluid. This has cut fuel use and reduced the potential for thermal damage to the heat transfer fluid, process fluid and process equipment.

  15. Efficiency Improvement through Reduction in Friction and Wear in Powertrain Systems

    SciTech Connect (OSTI)

    Michael Killian

    2009-09-30T23:59:59.000Z

    The objective of this project is to improve the efficiency of truck drivelines through reduction of friction and parasitic losses in transmission and drive axles. Known efficiencies for these products exceeded 97 percent, so the task was not trivial. The project relied on a working relationship between modeling and hardware testing. Modeling was to shorten the development cycle by guiding the selection of materials, processes and strategies. Bench top and fixture tests were to validate the models. Modeling was performed at a world class, high academic level, but in the end, modeling did not impact the hardware development as much as intended. Insights leading to the most significant accomplishments came from bench top and fixture tests and full scale dynamometer tests. A key development in the project was the formulation of the implementation strategy. Five technical elements with potential to minimize friction and parasitic losses were identified. These elements included churning, lubrication, surface roughness, coatings and textures. An interesting fact is that both Caterpillar and Eaton independently converged on the same set of technical elements in formulating their implementation strategies. Exploiting technical elements of the implementation strategy had a positive impact on transmission and drive axle efficiencies. During one dynamometer test of an Eaton Best Tech 1 transmission, all three gear ranges tested: Under drive, direct drive and over drive, showed efficiencies greater than 99 percent. Technology boosts to efficiency for transmissions reached 1 percent, while efficiency improvements to drive axle pushed 2 percent. These advancements seem small, but the accomplishment is large considering that these products normally run at greater than 97 percent efficiency. Barriers and risks to implementing these technology elements are clear. Schemes using a low fill sump and spray tubes endanger the gears and bearings by lubricant starvation. Gear coatings have exhibited durability issues, stripping away under conditions less demanding than 750,000 miles in service on the road. Failed coatings compound the problem by contaminating the lubricant with hard particles. Under the most severe conditions, super finished surfaces may polish further, reaching a surface roughness unable to support the critical oil film thickness. Low viscosity and low friction lubricants may not protect the gears and bearings adequately leading to excessive pitting, wear and noise. Additives in low friction oils may not stay in solution or suspended thus settling to the bottom and unavailable when they are needed most. Technical barriers and risks can be overcome through engineering, but two barriers remain formidable: (1) cost of the technology and (2) convincing fleet owners that the technology provides a tangible benefit. Dry sumps lower lubricant operating temperatures so the removal of heat exchangers and hoses and reduced demand on engine cooling systems justify their use. The benefits of surface texturing are varied and remain unproven. Lubricant costs seem manageable, but the cost of super finishing and gear coating are high. These are issues of scale and processing technology. Going across the board with gear super finishing and coating will reduce costs. Pushing the envelope to applications with higher torque and higher power density should drive the adoption of these technologies. Fleet owners are an educated and seasoned lot. Only technology measureable in dollars returned is used on truck fleets. To convince fleet owners of the benefit of these technologies, new precision in measuring fuel efficiency must be introduced. Legislation for a minimum standard in truck miles per gallon would also enable the use of these technologies. Improving the efficiency of truck transmissions and axle will make a noticeable impact on the fuel consumption by heavy vehicles in the United States. However, the greatest benefit will come when all the individual efficiency technologies like hybrid power, aerodynamic fairings, auxiliary power units, super

  16. Heat pump system

    DOE Patents [OSTI]

    Swenson, Paul F. (Cleveland, OH); Moore, Paul B. (Fedhaurn, FL)

    1982-01-01T23:59:59.000Z

    An air heating and cooling system for a building includes an expansion-type refrigeration circuit and a heat engine. The refrigeration circuit includes two heat exchangers, one of which is communicated with a source of indoor air from the building and the other of which is communicated with a source of air from outside the building. The heat engine includes a heat rejection circuit having a source of rejected heat and a primary heat exchanger connected to the source of rejected heat. The heat rejection circuit also includes an evaporator in heat exchange relation with the primary heat exchanger, a heat engine indoor heat exchanger, and a heat engine outdoor heat exchanger. The indoor heat exchangers are disposed in series air flow relationship, with the heat engine indoor heat exchanger being disposed downstream from the refrigeration circuit indoor heat exchanger. The outdoor heat exchangers are also disposed in series air flow relationship, with the heat engine outdoor heat exchanger disposed downstream from the refrigeration circuit outdoor heat exchanger. A common fluid is used in both of the indoor heat exchanges and in both of the outdoor heat exchangers. In a first embodiment, the heat engine is a Rankine cycle engine. In a second embodiment, the heat engine is a non-Rankine cycle engine.

  17. Geothermal heating

    SciTech Connect (OSTI)

    Aureille, M.

    1982-01-01T23:59:59.000Z

    The aim of the study is to demonstrate the viability of geothermal heating projects in energy and economic terms and to provide nomograms from which an initial estimate may be made without having to use data-processing facilities. The effect of flow rate and temperature of the geothermal water on drilling and on the network, and the effect of climate on the type of housing are considered.

  18. Systematic Breakdown of Amontons' Law of Friction for an Elastic Object Locally Obeying Amontons' Law

    E-Print Network [OSTI]

    Michio Otsuki; Hiroshi Matsukawa

    2013-04-04T23:59:59.000Z

    In many sliding systems consisting of solid object on a solid substrate under dry condition, the friction force does not depend on the apparent contact area and is proportional to the loading force. This behaviour is called Amontons' law and indicates that the friction coefficient, or the ratio of the friction force to the loading force, is constant. Here, however, using numerical and analytical methods, we show that Amontons' law breaks down systematically under certain conditions for an elastic object experiencing a friction force that locally obeys Amontons' law. The macroscopic static friction coefficient, which corresponds to the onset of bulk sliding of the object, decreases as pressure or system length increases. This decrease results from precursor slips before the onset of bulk sliding, and is consistent with the results of certain previous experiments. The mechanisms for these behaviours are clarified. These results will provide new insight into controlling friction.

  19. Water and Space Heating Heat Pumps 

    E-Print Network [OSTI]

    Kessler, A. F.

    1985-01-01T23:59:59.000Z

    This paper discusses the design and operation of the Trane Weathertron III Heat Pump Water Heating System and includes a comparison of features and performance to other domestic water heating systems. Domestic water is generally provided through...

  20. Water and Space Heating Heat Pumps

    E-Print Network [OSTI]

    Kessler, A. F.

    1985-01-01T23:59:59.000Z

    This paper discusses the design and operation of the Trane Weathertron III Heat Pump Water Heating System and includes a comparison of features and performance to other domestic water heating systems. Domestic water is generally provided through...

  1. Industrial Waste Heat Recovery Using Heat Pipes 

    E-Print Network [OSTI]

    Ruch, M. A.

    1981-01-01T23:59:59.000Z

    For almost a decade now, heat pipes with secondary finned surfaces have been utilized in counter flow heat exchangers to recover sensible energy from industrial exhaust gases. Over 3,000 such heat exchangers are now in service, recovering...

  2. Interplay of friction and noise and enhancement of disoriented chiral condensate

    E-Print Network [OSTI]

    A. K. Chaudhuri

    2000-11-01T23:59:59.000Z

    Using the Langevin equation for the linear $\\sigma$ model, we have investigated the effect of friction and noise on the possible disoriented chiral condensate formation. Friction and noise are supposed to suppress longwavelength oscillations and growth of disoriented chiral condensate domains. Details simulation shows that for heavy ion collisions, interplay of friction and noise occur in such a manner that formation of disoriented chiral condensate domains are enhanced.

  3. Heating systems for heating subsurface formations

    DOE Patents [OSTI]

    Nguyen, Scott Vinh (Houston, TX); Vinegar, Harold J. (Bellaire, TX)

    2011-04-26T23:59:59.000Z

    Methods and systems for heating a subsurface formation are described herein. A heating system for a subsurface formation includes a sealed conduit positioned in an opening in the formation and a heat source. The sealed conduit includes a heat transfer fluid. The heat source provides heat to a portion of the sealed conduit to change phase of the heat transfer fluid from a liquid to a vapor. The vapor in the sealed conduit rises in the sealed conduit, condenses to transfer heat to the formation and returns to the conduit portion as a liquid.

  4. Particulate residue separators for harvesting devices

    SciTech Connect (OSTI)

    Hoskinson, Reed L.; Kenney, Kevin L.; Wright, Christopher T.; Hess, John R.

    2010-06-29T23:59:59.000Z

    A particulate residue separator and a method for separating a particulate residue stream may include a plenum borne by a harvesting device, and have a first, intake end and a second, exhaust end; first and second particulate residue air streams which are formed by the harvesting device and which travel, at least in part, along the plenum and in a direction of the second, exhaust end; and a baffle assembly which is located in partially occluding relation relative to the plenum, and which substantially separates the first and second particulate residue air streams.

  5. Methods of separating particulate residue streams

    DOE Patents [OSTI]

    Hoskinson, Reed L. (Rigby, ID); Kenney, Kevin L. (Idaho Falls, ID); Wright, Christopher T. (Idaho Falls, ID); Hess, J. Richard (Idaho Falls, ID)

    2011-04-05T23:59:59.000Z

    A particulate residue separator and a method for separating a particulate residue stream may include an air plenum borne by a harvesting device, and have a first, intake end and a second, exhaust end; first and second particulate residue air streams that are formed by the harvesting device and that travel, at least in part, along the air plenum and in a direction of the second, exhaust end; and a baffle assembly that is located in partially occluding relation relative to the air plenum and that substantially separates the first and second particulate residue air streams.

  6. Vehicle Technologies Office Merit Review 2015: Engine Friction Reduction – Part II (Base fluid and additive technologies)

    Broader source: Energy.gov [DOE]

    Presentation given by Argonne National Laboratory at 2015 DOE Hydrogen and Fuel Cells Program and vehicle technologies office annual merit review and peer evaluation meeting about engine friction...

  7. asbestos-free friction lining: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    along the separation coordinate and thus to unambiguously disentangle the effects of free-energy and local friction on the separation kinetics. For tightly coordinated water...

  8. Characterization Report on Sand, Slag, and Crucible Residues and on Fluoride Residues

    SciTech Connect (OSTI)

    Murray, A.M.

    1999-02-10T23:59:59.000Z

    This paper reports on the chemical characterization of the sand, slag, and crucible (SS and C) residues and the fluoride residues that may be shipped from the Rocky Flats Environmental Technology Site (RFETS) to Savannah River Site (SRS).

  9. Dead heat

    SciTech Connect (OSTI)

    Oppenheimer, M.; Boyle, R.H.

    1990-01-01T23:59:59.000Z

    This paper reports on the prospect of global warming. This paper proposes a workable solution, and a road map for getting there. The author explains how we became addicted to fossil fuels and evokes a bleak picture should this dependence continue. But the book also explores how industry can become a vehicle for solving, instead of precipitating, the global environmental crisis. The decoupling of energy from pollution can be accomplished without sacrificing prosperity by powering the economy with solar energy. Dead Heat takes us step by step to a greenhouse-friendly world fueled only by the sun.

  10. Friction Stir Spot Welding (FSSW) of Advanced High Strength Steel (AHSS)

    SciTech Connect (OSTI)

    Santella, M. L.; Hovanski, Yuri; Pan, Tsung-Yu

    2012-04-16T23:59:59.000Z

    Friction stir spot welding (FSSW) is applied to join advanced high strength steels (AHSS): galvannealed dual phase 780 MPa steel (DP780GA), transformation induced plasticity 780 MPa steel (TRIP780), and hot-stamped boron steel (HSBS). A low-cost Si3N4 ceramic tool was developed and used for making welds in this study instead of polycrystalline cubic boron nitride (PCBN) material used in earlier studies. FSSW has the advantages of solid-state, low-temperature process, and the ability of joining dissimilar grade of steels and thicknesses. Two different tool shoulder geometries, concave with smooth surface and convex with spiral pattern, were used in the study. Welds were made by a 2-step displacement control process with weld time of 4, 6, and 10 seconds. Static tensile lap-shear strength achieved 16.4 kN for DP780GA-HSBS and 13.2kN for TRIP780-HSBS, above the spot weld strength requirements by AWS. Nugget pull-out was the failure mode of the joint. The joining mechanism was illustrated from the cross-section micrographs. Microhardness measurement showed hardening in the upper sheet steel (DP780GA or TRIP780) in the weld, but softening of HSBS in the heat-affect zone (HAZ). The study demonstrated the feasibility of making high-strength AHSS spot welds with low-cost tools.

  11. Joint strength in high speed friction stir spot welded DP 980 steel

    SciTech Connect (OSTI)

    Saunders, Nathan; Miles, Michael; Hartman, Trent; Hovanski, Yuri; Hong, Sung Tae; Steel, Russell

    2014-05-01T23:59:59.000Z

    High speed friction stir spot welding was applied to 1.2 mm thick DP 980 steel sheets under different welding conditions, using PCBN tools. The range of vertical feed rates used during welding was 2.5 mm – 102 mm per minute, while the range of spindle speeds was 2500 – 6000 rpm. Extended testing was carried out for five different sets of welding conditions, until tool failure. These welding conditions resulted in vertical welding loads of 3.6 – 8.2 kN and lap shear tension failure loads of 8.9 – 11.1 kN. PCBN tools were shown, in the best case, to provide lap shear tension fracture loads at or above 9 kN for 900 spot welds, after which tool failure caused a rapid drop in joint strength. Joint strength was shown to be strongly correlated to bond area, which was measured from weld cross sections. Failure modes of the tested joints were a function of bond area and softening that occurred in the heat-affected zone.

  12. Microstructure characterization of the stir zone of submerged friction stir processed aluminum alloy 2219

    SciTech Connect (OSTI)

    Feng, Xiuli, E-mail: feng.97@osu.edu [Welding Engineering Program, Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43221 (United States); State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Liu, Huijie, E-mail: liuhj@hit.edu.cn [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China); Lippold, John C., E-mail: lippold.1@osu.edu [Welding Engineering Program, Department of Materials Science and Engineering, The Ohio State University, Columbus, OH 43221 (United States)

    2013-08-15T23:59:59.000Z

    Aluminum alloy 2219-T6 was friction stir processed using a novel submerged processing technique to facilitate cooling. Processing was conducted at a constant tool traverse speed of 200 mm/min and spindle rotation speeds in the range from 600 to 800 rpm. The microstructural characteristics of the base metal and processed zone, including grain structure and precipitation behavior, were studied using optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Microhardness maps were constructed on polished cross sections of as-processed samples. The effect of tool rotation speed on the microstructure and hardness of the stir zone was investigated. The average grain size of the stir zone was much smaller than that of the base metal, but the hardness was also lower due to the formation of equilibrium ? precipitates from the base metal ?? precipitates. Stir zone hardness was found to decrease with increasing rotation speed (heat input). The effect of processing conditions on strength (hardness) was rationalized based on the competition between grain refinement strengthening and softening due to precipitate overaging. - Highlights: • SZ grain size (? 1 ?m) is reduced by over one order of magnitude relative to the BM. • Hardness in the SZ is lower than that of the precipitation strengthened BM. • Metastable ?? in the base metal transforms to equilibrium ? in the stir zone. • Softening in the SZ results from a decrease of precipitation strengthening.

  13. Radiative friction on an excited atom moving in vacuum

    E-Print Network [OSTI]

    Wei Guo

    2012-04-30T23:59:59.000Z

    It is known that, when an excited atom spontaneously emits one photon, two effects are produced. First, the atom's internal and external states are entangled with the states of the emitted photon. Second, the atom receives a momentum transfered from the photon. In this work, the dynamics of such an atom in vacuum is studied. Through a specific calculation, it is demonstrated that these effects cause the atom to experience, on average, a friction force opposite to its initial velocity. Properties of the force are also discussed.

  14. Friction stir welding tool and process for welding dissimilar materials

    DOE Patents [OSTI]

    Hovanski, Yuri; Grant, Glenn J; Jana, Saumyadeep; Mattlin, Karl F

    2013-05-07T23:59:59.000Z

    A friction stir welding tool and process for lap welding dissimilar materials are detailed. The invention includes a cutter scribe that penetrates and extrudes a first material of a lap weld stack to a preselected depth and further cuts a second material to provide a beneficial geometry defined by a plurality of mechanically interlocking features. The tool backfills the interlocking features generating a lap weld across the length of the interface between the dissimilar materials that enhances the shear strength of the lap weld.

  15. Evaluation of friction loss in flexible and galvanized duct

    E-Print Network [OSTI]

    Zimmermann, Carlos Michael Alberto

    1985-01-01T23:59:59.000Z

    for Friction Loss in Straight Runs of Duct (a'Ipha=0. 10). 21 Ill Static Pressure Data Converted to Equivalent Lengths. 23 IV Duncan's Multiple Range Test of Variability for Equivalent Lengths of 90 Degree Elbows (al pha=0. IO). 26 V Student t Test... in the system was controlled by a discharge damper and metered with an orifice meter. The static pressure data was collected by the use of a pizometer ring located at the exhaust portion of the test apparatus where the flexible duct was connected...

  16. Damping of Neutron Star Shear Modes by Superfluid Friction

    E-Print Network [OSTI]

    P. B. Jones

    2003-01-07T23:59:59.000Z

    The forced motion of superfluid vortices in shear oscillations of rotating solid neutron star matter produces damping of the mode. A simple model of the unpinning and repinning processes is described, with numerical calculations of the consequent energy decay times. These are of the order of 1 s or more for typical anomalous X-ray pulsars but become very short for the general population of radio pulsars. The superfluid friction processes considered here may also be significant for the damping of r-modes in rapidly rotating neutron stars.

  17. Dual source heat pump

    DOE Patents [OSTI]

    Ecker, Amir L. (Dallas, TX); Pietsch, Joseph A. (Dallas, TX)

    1982-01-01T23:59:59.000Z

    What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating the fluid in heat exchange relationship with a refrigerant fluid; at least two refrigerant heat exchangers, one for effecting heat exchange with the fluid and a second for effecting heat exchange between refrigerant and a heat exchange fluid and the ambient air; a compressor for efficiently compressing the refrigerant; at least one throttling valve for throttling liquid refrigerant; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and direction of flow of the refrigerant therethrough for selecting a particular mode of operation. The heat exchange fluid provides energy for defrosting the second heat exchanger when operating in the air source mode and also provides a alternate source of heat.

  18. Segmented heat exchanger

    DOE Patents [OSTI]

    Baldwin, Darryl Dean (Lafayette, IN); Willi, Martin Leo (Dunlap, IL); Fiveland, Scott Byron (Metamara, IL); Timmons, Kristine Ann (Chillicothe, IL)

    2010-12-14T23:59:59.000Z

    A segmented heat exchanger system for transferring heat energy from an exhaust fluid to a working fluid. The heat exchanger system may include a first heat exchanger for receiving incoming working fluid and the exhaust fluid. The working fluid and exhaust fluid may travel through at least a portion of the first heat exchanger in a parallel flow configuration. In addition, the heat exchanger system may include a second heat exchanger for receiving working fluid from the first heat exchanger and exhaust fluid from a third heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the second heat exchanger in a counter flow configuration. Furthermore, the heat exchanger system may include a third heat exchanger for receiving working fluid from the second heat exchanger and exhaust fluid from the first heat exchanger. The working fluid and exhaust fluid may travel through at least a portion of the third heat exchanger in a parallel flow configuration.

  19. LOW-ENGINE-FRICTION TECHNOLOGY FOR ADVANCED NATURAL-GAS RECIPROCATING ENGINES

    SciTech Connect (OSTI)

    Victor Wong; Tian Tian; Luke Moughon; Rosalind Takata; Jeffrey Jocsak

    2006-03-31T23:59:59.000Z

    This program aims at improving the efficiency of advanced natural-gas reciprocating engines (ANGRE) by reducing piston and piston ring assembly friction without major adverse effects on engine performance, such as increased oil consumption and wear. An iterative process of simulation, experimentation and analysis is being followed towards achieving the goal of demonstrating a complete optimized low-friction engine system. To date, a detailed set of piston and piston-ring dynamic and friction models have been developed and applied that illustrate the fundamental relationships among mechanical, surface/material and lubricant design parameters and friction losses. Demonstration of low-friction ring-pack designs in the Waukesha VGF 18GL engine confirmed total engine FEMP (friction mean effective pressure) reduction of 7-10% from the baseline configuration without significantly increasing oil consumption or blow-by flow. This represents a substantial (30-40%) reduction of the ringpack friction alone. The measured FMEP reductions were in good agreement with the model predictions. Further improvements via piston, lubricant, and surface designs offer additional opportunities. Tests of low-friction lubricants are in progress and preliminary results are very promising. The combined analysis of lubricant and surface design indicates that low-viscosity lubricants can be very effective in reducing friction, subject to component wear for extremely thin oils, which can be mitigated with further lubricant formulation and/or engineered surfaces. Hence a combined approach of lubricant design and appropriate wear reduction offers improved potential for minimum engine friction loss. Piston friction studies indicate that a flatter piston with a more flexible skirt, together with optimizing the waviness and film thickness on the piston skirt offer significant friction reduction. Combined with low-friction ring-pack, material and lubricant parameters, a total power cylinder friction reduction of 30-50% is expected, translating to an engine efficiency increase of two percentage points from its current baseline towards the goal of 50% ARES engine efficiency. The design strategies developed in this study have promising potential for application in all modern reciprocating engines as they represent simple, low-cost methods to extract significant fuel savings. The current program has possible spinoffs and applications in other industries as well, including transportation, CHP, and diesel power generation. The progress made in this program has wide engine efficiency implications, and potential deployment of low-friction engine components or lubricants in the near term is possible as current investigations continue.

  20. Contributions to the development of residual discretizations

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Contributions to the development of residual discretizations for hyperbolic conservation laws with application to shallow water flows Manuscript submitted in fulfillment of the requirements for the obtention;Contents 1 Overview 9 1.1 Residual schemes for hyperbolic conservation laws

  1. Asymptotics for GARCH Squared Residual Correlations

    E-Print Network [OSTI]

    Kokoszka, Piotr

    Asymptotics for GARCH Squared Residual Correlations Istv'an Berkes \\Lambda A. R'enyi Institute a GARCH(p; q) model. Denoting by â?? r n (k); k â?? 1; these autocorrelations computed from a realization words and phrases: GARCH(p; q) sequence, quasi--maximum likelihood esti­ mator, squared residuals

  2. University of Pittsburgh Residual Funds on

    E-Print Network [OSTI]

    Sibille, Etienne

    University of Pittsburgh Residual Funds on FINANCIAL GUIDELINE Subject: Sponsored Projects I by the sponsor. Funds cannot be unilaterally retained by the University. Failure to return residual funds related funds on sponsored grants and contracts on the financial accounting records of the University

  3. Data Conversion in Residue Number System

    E-Print Network [OSTI]

    Zilic, Zeljko

    for direct conversion when interaction with the real analog world is required. We first develop two efficient schemes for direct analog-to-residue conversion. Another efficient scheme for direct residue analogique réel est nécessaire. Nous dévelopons deux systèmes efficaces pour la conversion directe du domaine

  4. Heat transfer coefficients in two-dimensional Yukawa systems (numerical simulations)

    SciTech Connect (OSTI)

    Khrustalyov, Yu. V., E-mail: yuri.khrustalyov@gmail.com; Vaulina, O. S. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2013-05-15T23:59:59.000Z

    New data on heat transfer in two-dimensional Yukawa systems have been obtained. The results of a numerical study of the thermal conductivity for equilibrium systems with parameters close to the conditions of laboratory experiments in dusty plasma are presented. The Green-Kubo relations are used to calculate the heat transfer coefficients. The influence of dissipation (internal friction) on the heat transfer processes in nonideal systems is studied. New approximations are proposed for the thermal conductivity and diffusivity for nonideal dissipative systems. The results obtained are compared with the existing experimental and numerical data.

  5. Geothermal heat pumps for heating and cooling

    SciTech Connect (OSTI)

    Garg, S.C.

    1994-03-01T23:59:59.000Z

    Naval Facilities Engineering Service Center (NFESC) has been tasked by Naval Shore Facilities Energy Office to evaluate the NAS Patuxent River ground-source heat pump (GHP) installation. A large part of a building`s energy consumption consists of heating and air conditioning for occupant comfort. The space heating requirements are normally met by fossil-fuel-fired equipment or electric resistance heating. Cooling is provided by either air conditioners or heat pumps, both using electricity as an energy source.

  6. Micro-origin of Macro-strength: Friction

    E-Print Network [OSTI]

    Alex X. Jerves; José E. Andrade

    2013-02-05T23:59:59.000Z

    This paper presents an analytical study about the behavior of arbitrary shaped and sized non-cohesive two-dimensional granular materials. Several mechanical properties and relations are unraveled by connecting micro and macro scales in an explicit fashion that, at the same time, provides the basis of an analytical-theoretical framework for the development of new multi-scale techniques. Furthermore, the work herein presented is based on three main ideas that are developed and connected progressively; namely, the obtention of explicit expressions that enable us to relate micro-scale parameters, such as contact forces and fabric, to stress as a macro (continuum) physical property. Then, with these powerful tools, physical connections and relations between the mentioned micro-parameters and macro-constitutive parameters, in specific, Mohr-Coulomb's mobilized internal friction angle, are established. Finally, a non-linear optimization problem, which includes physical constraints at the contact point level, is proposed and solved in order to find the limit (maximum) internal friction angle in terms of the aforementioned micro-parameters. Thus, throughout this theoretical study, some important features about strength, anisotropy, contact buckling, and non-uniqueness of systems of contact forces are extracted, allowing us to have a deeper insight, as well as, a better understanding of the mechanical behavior of such complex-to-model materials.

  7. Friction Stir Spot Welding of DP780 Carbon Steel

    SciTech Connect (OSTI)

    Santella, Michael L [ORNL; Hovanski, Yuri [ORNL; Frederick, David Alan [ORNL; Grant, Glenn J [ORNL; Dahl, Michael E [ORNL

    2010-01-01T23:59:59.000Z

    Friction stir spot welds were made in uncoated and galvannealed DP780 sheets using polycrystalline boron nitride stir tools. The tools were plunged at either a single continuous rate or in two segments consisting of a relatively high rate followed by a slower rate of shorter depth. Welding times ranged from 1 to 10 s. Increasing tool rotation speed from 800 to 1600 rev min{sup -1} increased strength values. The 2-segment welding procedures also produced higher strength joints. Average lap shear strengths exceeding 10 {center_dot} 3 kN were consistently obtained in 4 s on both the uncoated and the galvannealed DP780. The likelihood of diffusion and mechanical interlocking contributing to bond formation was supported by metallographic examinations. A cost analysis based on spot welding in automobile assembly showed that for friction stir spot welding to be economically competitive with resistance spot welding the cost of stir tools must approach that of resistance spot welding electrode tips.

  8. Mass/ Inertia and Joint Friction Minimization for a Lowforce Fivedof Haptic Device*

    E-Print Network [OSTI]

    Papadopoulos, Evangelos

    Mass/ Inertia and Joint Friction Minimization for a Low­force Five­dof Haptic Device* Kostas and joint friction for a low ­ force five ­ dof haptic device. The haptic device is optimized along a typical path with proper tolerances, rather than at some workspace operating point. The device, part

  9. On the rate-independent limit of systems with dry friction and small viscosity

    E-Print Network [OSTI]

    Mielke, Alexander

    On the rate-independent limit of systems with dry friction and small viscosity Messoud A. Efendiev of this work is to present a model which is able to account for viscous as well as for dry-friction effects slow time scale, in which viscous transitions are seen as instantaneous jumps. However, effects of dry

  10. Dense granular flows: two-particle argument accounts for friction-like constitutive law with threshold

    E-Print Network [OSTI]

    Boyer, Edmond

    Dense granular flows: two-particle argument accounts for friction-like constitutive law that exhibits a flow threshold expressed as a finite effective friction at flow onset. The value 83.10.Gr 83.60.La I. INTRODUCTION Dense flows of dry granular materials and granular pastes is still

  11. MODELING AND ANALYSIS OF THE DYNAMICS OF DRY-FRICTION-DAMPED STRUCTURAL SYSTEMS

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    MODELING AND ANALYSIS OF THE DYNAMICS OF DRY-FRICTION-DAMPED STRUCTURAL SYSTEMS by Olivier J . . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.2.1 Nonlinear methods for the analysis of friction-damped systems . . . . . . . . . . . . . . . . . . . . . . . . 15 II. HYBRID FREQUENCY-TIME DOMAIN METHODS FOR THE ANALYSIS OF COMPLEX STRUCTURAL SYSTEMS WITH DRY

  12. Anomalous density dependence of static friction in sand Viktor K. Horvath,1

    E-Print Network [OSTI]

    Jánosi, Imre M.

    Anomalous density dependence of static friction in sand Viktor K. Horva´th,1 Imre M. Ja´nosi,2; revised manuscript received 26 April 1996 We measured experimentally the static friction force Fs on the surface of a glass rod immersed in dry sand. We observed that Fs is extremely sensitive to the closeness

  13. Axis control using model predictive control: identification and friction effect reduction

    E-Print Network [OSTI]

    Boyer, Edmond

    Axis control using model predictive control: identification and friction effect reduction Pedro this numerical model is used to synthetize a predictive GPC controller reducing the impact of the friction Rodriguez-Ayerbe, Didier Dumur, Sylvain Lavernhe** * SUPELEC- E3S, Automatic Control, 3 rue Joliot Curie

  14. PublishedbyManeyPublishing(c)IOMCommunicationsLtd Friction stir welding of dissimilar alloys a

    E-Print Network [OSTI]

    Cambridge, University of

    PublishedbyManeyPublishing(c)IOMCommunicationsLtd Friction stir welding of dissimilar alloys ­ a perspective T. DebRoy*1 and H. K. D. H. Bhadeshia2 Friction stir welding does not involve bulk melting. The purpose of this special issue of Science and Technology of Welding and Joining was to assess the status

  15. Recent Advances in Friction Stir Welding Process, Weldment Structure and Properties

    E-Print Network [OSTI]

    Cambridge, University of

    Recent Advances in Friction Stir Welding ­ Process, Weldment Structure and Properties R. Nandan, T University of Cambridge, Cambridge CB2 3QZ, U.K. Abstract Friction stir welding is a refreshing approach flow during welding, elements of tool design, understanding defect formation and the structure

  16. Masatsu kakuhan setsugo "Friction Stir Welding Complete aspects of FSW" Japan Welding Society

    E-Print Network [OSTI]

    Cambridge, University of

    Masatsu kakuhan setsugo ­ "Friction Stir Welding ­ Complete aspects of FSW" Japan Welding Society years ago that the Friction Stir Welding (FSW) method was proposed by TWI. Because FSW is a solid state welding method, the peak temperature reached during FSW welding is lower than the traditional welding

  17. Modifications in the AA5083 Johnson-Cook Material Model for Use in Friction Stir Welding

    E-Print Network [OSTI]

    Grujicic, Mica

    Modifications in the AA5083 Johnson-Cook Material Model for Use in Friction Stir Welding, material microstructure and properties in friction stir welding welds of AA5083 (a non welding, Johnson-Cook material model 1. Introduction In this study, an attempt is made to modify

  18. Process Modeling of Ti-6Al-4V Linear Friction Welding (LFW)

    E-Print Network [OSTI]

    Grujicic, Mica

    Process Modeling of Ti-6Al-4V Linear Friction Welding (LFW) Mica Grujicic, G. Arakere, B finite-element analysis of the linear friction welding (LFW) process is combined with the basic physical in the open literature revealed that the weld region consists of a thermo- mechanically affected zone (TMAZ

  19. Modeling of AA5083 Material-Microstructure Evolution During Butt Friction-Stir Welding

    E-Print Network [OSTI]

    Grujicic, Mica

    Modeling of AA5083 Material-Microstructure Evolution During Butt Friction-Stir Welding M. Grujicic yet a fairly comprehensive overview of the friction stir welding (FSW) process is provided-element procedure developed in our prior study. Particular attention is given to proper modeling of the welding work

  20. Acta Materialia 59 (2011) 2020-2028 Back of the envelope calculations in friction stir welding

    E-Print Network [OSTI]

    Cambridge, University of

    2011-01-01T23:59:59.000Z

    : friction stir welding; modeling; theory; velocity field; peak temperature; torque; hardness; aluminum welding (FSW), well-tested analytical models of materials flow, peak temperatures, torque, and weldActa Materialia 59 (2011) 2020-2028 1 Back of the envelope calculations in friction stir welding

  1. Nonlinear shear wave interaction at a frictional interface: Energy dissipation and generation of harmonics

    E-Print Network [OSTI]

    Norris, Andrew

    Nonlinear shear wave interaction at a frictional interface: Energy dissipation and generation solids, brought into frictional contact by remote normal compression. A shear wave, either time har the partition of energy resulting from a time harmonic obliquely incident plane SH wave reflected and refracted

  2. Measurement of friction noise versus contact area of rough surfaces weakly loaded

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    contact area. The friction-induced vibration is generated by the sliding of two rough surfaces. The normal load is low leading to a weak contact. The normal load and the sliding velocity are maintained constant], friction noises can be classified in two types depending on the contact pressure. When the contact pressure

  3. Long Term Friction: from Stick-Slip to Stable Sliding Christophe Voisin1

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Long Term Friction: from Stick-Slip to Stable Sliding Christophe Voisin1 , François Renard1 for friction and plastic deformation and pressure solution creep to be efficient on the same timescale. During vanishing, eventually reaching the stable sliding regime. Concomitantly, the contact interface, observed

  4. Long Term Friction: from Stick-Slip to Stable Sliding1 Christophe Voisin1

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Long Term Friction: from Stick-Slip to Stable Sliding1 Christophe Voisin1 , François Renard1, salt, an analogue for natural8 faults, allows for frictional processes plastic deformation and pressure sliding regime. Concomitantly, the contact13 interface, observed under the microscope, develops a striated

  5. Department of Mechanical Engineering Fall 2011 Heavy Duty Diesel Engine Friction Reduction

    E-Print Network [OSTI]

    Demirel, Melik C.

    PENNSTATE Department of Mechanical Engineering Fall 2011 Heavy Duty Diesel Engine Friction the friction losses of a heavy duty diesel engine. In addition, a tear down procedure needed to be created needs Discussed test cell configuration with Diesel Combustion & Emissions Laboratory Performed

  6. ccsd-00000893(version1):28Nov2003 Sliding Friction at a Rubber/Brush Interface

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ccsd-00000893(version1):28Nov2003 Sliding Friction at a Rubber/Brush Interface Lionel Bureau) rubber network sliding, at low velocity, on a substrate on which PDMS chains are end-tethered. We thus the friction, depending on their areal density. Casoli et al.9 further studied the behaviour of such rubber

  7. Visualizing stickslip: experimental observations of processes governing the nucleation of frictional sliding

    E-Print Network [OSTI]

    Fineberg, Jay

    Charles-Augustin de Coulomb repeated the experiments adding the first formulation of dynamic friction laws of frictional sliding This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2009 J. Phys. D: Appl. Phys. 42 214016 (http://iopscience.iop.org/0022

  8. Resource Letter: FMMLS-1: Friction at macroscopic and microscopic length scales

    E-Print Network [OSTI]

    Krim, Jacqueline

    as their weights are equal. A third law, at- tributed to French physicist Charles Augustin Coulomb bet- ter known is independent of velocity for ordinary sliding speeds. Amontons' and Coulomb's laws have far outlived a variety of friction. Books, reviews, and journal articles are cited for the following topics: History of friction

  9. ORIGINAL PAPER 1D Model of Precursors to Frictional Stick-Slip Motion Allowing

    E-Print Network [OSTI]

    Scheibert, Julien

    ], using a 1D spring-block model with a simple Amontons-Coulomb (AC) friction law, showed that the length November 2011 Ó Springer Science+Business Media, LLC 2011 Abstract In this article, we studythe dynamic], using a one-dimen- sional (1D) spring-block model with a complex time- dependent friction law, produced

  10. Numerical Study on Transverse Friction of a Slender Rod Contacting the Seabed 

    E-Print Network [OSTI]

    Lu, Hang

    2012-10-19T23:59:59.000Z

    support force and longitudinal (along the direction of the rod) friction from soils of the seabed while the transverse (in the direction transverse to the slender rod) friction between the rod and the seabed soils is not considered. In this study, we...

  11. Homogenization in non linear dynamics due to frictional contact Peillex G. a

    E-Print Network [OSTI]

    Boyer, Edmond

    homogenization process and its influence on the behavior of a composite under non linear dynamic loading due homogenization process, coupled with an homogenization of the frictional contact, enables replacing the entire in the heterogeneous models are identified by using the relocalization process and a frictional contact dynamic

  12. Heat transfer and pressure drop for air flow through enhanced passages

    SciTech Connect (OSTI)

    Obot, N.T.; Esen, E.B.

    1992-06-01T23:59:59.000Z

    An extensive experimental investigation was carried out to determine the pressure drop and heat transfer characteristics for laminar, transitional and turbulent flow of air through a smooth passage and twenty-three enhanced passages. The internal surfaces of all enhanced passages had spirally shaped geometries; these included fluted, finned/ribbed and indented surfaces. The Reynolds number (Re) was varied between 400 and 50000. The effect of heat transfer (wall cooling or fluid heating) on pressure drop is most significant within the transition region; the recorded pressure drop with heat transfer is much higher than that without heat transfer. The magnitude of this effect depends markedly on the average surface temperature and, to a lesser extent, on the geometric characteristics of the enhanced surfaces. When the pressure drop data are reduced as values of the Fanning friction factor(f), the results are about the same with and without heat transfer for turbulent flow, with moderate differences in the laminar and transition regions.

  13. Heat transfer and pressure drop for air flow through enhanced passages. Final report

    SciTech Connect (OSTI)

    Obot, N.T.; Esen, E.B.

    1992-06-01T23:59:59.000Z

    An extensive experimental investigation was carried out to determine the pressure drop and heat transfer characteristics for laminar, transitional and turbulent flow of air through a smooth passage and twenty-three enhanced passages. The internal surfaces of all enhanced passages had spirally shaped geometries; these included fluted, finned/ribbed and indented surfaces. The Reynolds number (Re) was varied between 400 and 50000. The effect of heat transfer (wall cooling or fluid heating) on pressure drop is most significant within the transition region; the recorded pressure drop with heat transfer is much higher than that without heat transfer. The magnitude of this effect depends markedly on the average surface temperature and, to a lesser extent, on the geometric characteristics of the enhanced surfaces. When the pressure drop data are reduced as values of the Fanning friction factor(f), the results are about the same with and without heat transfer for turbulent flow, with moderate differences in the laminar and transition regions.

  14. A PERSPECTIVE ON THE NUMERICAL AND EXPERIMENTAL CHARACTERISTICS OF MULTI-MODE DRY-FRICTION WHIP AND WHIRL

    E-Print Network [OSTI]

    Wilkes, Jason C.

    2010-01-16T23:59:59.000Z

    interactions. The interaction at the rub surface is modeled using a nonlinear Hunt and Crossley contact model with coulomb friction. Dry-friction simulations are performed for specific test cases and compared against experimental data to determine the validity...

  15. Quantity, quality, and availability of waste heat from United States thermal power generation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gingerich, Daniel B; Mauter, Meagan S

    2015-06-10T23:59:59.000Z

    Secondary application of unconverted heat produced during electric power generation has the potential to improve the life-cycle fuel efficiency of the electric power industry and the sectors it serves. This work quantifies the residual heat (also known as waste heat) generated by U.S. thermal power plants and assesses the intermittency and transport issues that must be considered when planning to utilize this heat. Combining Energy Information Administration plant-level data with literature-reported process efficiency data, we develop estimates of the unconverted heat flux from individual U.S. thermal power plants in 2012. Together these power plants discharged an estimated 18.9 billion GJthmore »of residual heat in 2012, 4% of which was discharged at temperatures greater than 90 °C. We also characterize the temperature, spatial distribution, and temporal availability of this residual heat at the plant level and model the implications for the technical and economic feasibility of its end use. Increased implementation of flue gas desulfurization technologies at coal-fired facilities and the higher quality heat generated in the exhaust of natural gas fuel cycles are expected to increase the availability of residual heat generated by 10.6% in 2040.« less

  16. Quantity, quality, and availability of waste heat from United States thermal power generation

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gingerich, Daniel B [Carnegie Mellon Univ., Pittsburgh, PA (United States); Mauter, Meagan S [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    2015-06-10T23:59:59.000Z

    Secondary application of unconverted heat produced during electric power generation has the potential to improve the life-cycle fuel efficiency of the electric power industry and the sectors it serves. This work quantifies the residual heat (also known as waste heat) generated by U.S. thermal power plants and assesses the intermittency and transport issues that must be considered when planning to utilize this heat. Combining Energy Information Administration plant-level data with literature-reported process efficiency data, we develop estimates of the unconverted heat flux from individual U.S. thermal power plants in 2012. Together these power plants discharged an estimated 18.9 billion GJth of residual heat in 2012, 4% of which was discharged at temperatures greater than 90 °C. We also characterize the temperature, spatial distribution, and temporal availability of this residual heat at the plant level and model the implications for the technical and economic feasibility of its end use. Increased implementation of flue gas desulfurization technologies at coal-fired facilities and the higher quality heat generated in the exhaust of natural gas fuel cycles are expected to increase the availability of residual heat generated by 10.6% in 2040.

  17. Looping and reconfiguration dynamics of a flexible chain with internal friction

    E-Print Network [OSTI]

    Nairhita Samanta; Jayanta Ghosh; Rajarshi Chakrabarti

    2014-04-09T23:59:59.000Z

    In recent past, experiments and simulations have suggested that apart from the solvent friction, friction arising from the protein itself plays an important role in protein folding by affecting the intra-chain loop formation dynamics. This friction is termed as internal friction in the literature. Using a flexible Gaussian chain with internal friction we analyze the intra- chain reconfiguration and loop formation times for all three topology classes namely end-to- end, end-to-interior and interior-to-interior. In a nutshell, bypassing expensive simulations we show how simple models like that of Rouse and Zimm can support the single molecule experiment and computer simulation results on intra-chain diffusion coefficients, looping time and even can predict the effects of tail length on the looping time.

  18. Friction control using ultrasonic oscillation for rolling-element linear-motion guide

    SciTech Connect (OSTI)

    Oiwa, Takaaki [Shizuoka University, 3-5-1 Hamamatsu, Shizuoka 432-8651 (Japan)

    2006-01-15T23:59:59.000Z

    This article reports a friction-control method for rolling-element linear-motion guides used for precision positioning. In general, static friction greater than dynamic friction generates stick-slip motion and diminishes the positioning accuracy. Two ultrasonic actuators excite both the rail and the carriage of the guide to give relative displacements to bearing surfaces. In order to effectively propagate the vibration over the entire rail without damping, the actuator drives at that frequency with a half wavelength corresponding to the distances between the rail mounting bolts. This also minimizes undesirable vibration of the machine structure. Moreover, the bearing surfaces of the carriage are resonated by a second ultrasonic actuator. The experiments using a force sensor showed that the static and dynamic friction forces were reduced by approximately 25% at any place on the 600-mm-long rail. Moreover, excitation only at very low velocity decreased the static friction peak.

  19. Heat-Of-Reaction Chemical Heat Pumps--Possible Configurations 

    E-Print Network [OSTI]

    Kirol, L. D.

    1986-01-01T23:59:59.000Z

    Chemical heat pumps utilize working fluids which undergo reversible chemical changes. Mechanically driven reactive heat pump cycles or, alternatively, heat driven heat pumps in which either heat engine or heat pump working fluid is reactive...

  20. LOW-ENGINE-FRICTION TECHNOLOGY FOR ADVANCED NATURAL-GAS RECIPROCATING ENGINES

    SciTech Connect (OSTI)

    Victor Wong; Tian Tian; Luke Moughon; Rosalind Takata; Jeffrey Jocsak

    2005-09-30T23:59:59.000Z

    This program aims at improving the efficiency of advanced natural-gas reciprocating engines (ANGRE) by reducing piston and piston ring assembly friction without major adverse effects on engine performance, such as increased oil consumption and wear. An iterative process of simulation, experimentation and analysis is being followed towards achieving the goal of demonstrating a complete optimized low-friction engine system. To date, a detailed set of piston and piston-ring dynamic and friction models have been developed and applied that illustrate the fundamental relationships between design parameters and friction losses. Low friction ring designs have already been recommended in a previous phase, with full-scale engine validation partially completed. Current accomplishments include the addition of several additional power cylinder design areas to the overall system analysis. These include analyses of lubricant and cylinder surface finish and a parametric study of piston design. The Waukesha engine was found to be already well optimized in the areas of lubricant, surface skewness and honing cross-hatch angle, where friction reductions of 12% for lubricant, and 5% for surface characteristics, are projected. For the piston, a friction reduction of up to 50% may be possible by controlling waviness alone, while additional friction reductions are expected when other parameters are optimized. A total power cylinder friction reduction of 30-50% is expected, translating to an engine efficiency increase of two percentage points from its current baseline towards the goal of 50% efficiency. Key elements of the continuing work include further analysis and optimization of the engine piston design, in-engine testing of recommended lubricant and surface designs, design iteration and optimization of previously recommended technologies, and full-engine testing of a complete, optimized, low-friction power cylinder system.

  1. Multiple source heat pump

    DOE Patents [OSTI]

    Ecker, Amir L. (Duncanville, TX)

    1983-01-01T23:59:59.000Z

    A heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating a fluid in heat exchange relationship with a refrigerant fluid, at least three refrigerant heat exchangers, one for effecting heat exchange with the fluid, a second for effecting heat exchange with a heat exchange fluid, and a third for effecting heat exchange with ambient air; a compressor for compressing the refrigerant; at least one throttling valve connected at the inlet side of a heat exchanger in which liquid refrigerant is vaporized; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circuit and pump for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and directional flow of refrigerant therethrough for selecting a particular mode of operation. Also disclosed are a variety of embodiments, modes of operation, and schematics therefor.

  2. A LuGre Tire Friction Model with Exact Aggregate Dynamics Panagiotis Tsiotras, Efstathios Velenis and Michel Sorine

    E-Print Network [OSTI]

    Tsiotras, Panagiotis

    A LuGre Tire Friction Model with Exact Aggregate Dynamics Panagiotis Tsiotras, Efstathios Velenis and Michel Sorine Abstract-- The LuGre dynamic point contact friction model for the two-dimensional translation of a body on a surface has been used in the past to derive a model for the friction forces

  3. Role of friction in pattern formation in oscillated granular layers Sung Joon Moon, # J. B. Swift, and Harry L. Swinney

    E-Print Network [OSTI]

    Texas at Austin. University of

    Role of friction in pattern formation in oscillated granular layers Sung Joon Moon, # J. B. Swift grains. Our molecular dynamics simu­ lations reveal that friction is essential for realistic modeling at a container acceleration about 30% smaller than that observed in experiments and simulations with friction

  4. Incorporating friction and collective shear moves into a lattice gas Alex Dickson, Alice Nasto, and Aaron R. Dinner

    E-Print Network [OSTI]

    Dinner, Aaron

    Incorporating friction and collective shear moves into a lattice gas Alex Dickson, Alice Nasto a lattice-gas model that has been extended to include collective shear moves and friction interactions of the lattice with respect to one another, as opposed to biasing the individual movements of particles. Friction

  5. Friction anisotropy at Ni,,100...,,100... interfaces: Molecular dynamics studies Yue Qi and Yang-Tse Cheng

    E-Print Network [OSTI]

    Goddard III, William A.

    Friction anisotropy at Ni,,100...Õ,,100... interfaces: Molecular dynamics studies Yue Qi and Yang of Technology, Pasadena, California, 91125 Received 8 March 2002; published 30 August 2002 The friction theories predict that most perfect clean incommensurate interfaces would produce no static friction

  6. Role of friction in pattern formation in oscillated granular layers Sung Joon Moon,* J. B. Swift, and Harry L. Swinney

    E-Print Network [OSTI]

    Texas at Austin. University of

    Role of friction in pattern formation in oscillated granular layers Sung Joon Moon,* J. B. Swift as there are no elastic grains. Our molecular dynamics simulations reveal that friction is essential for realistic with friction. More importantly, even though square and hexagonal patterns form for a wide range

  7. Brownian motion with dry friction: Fokker-Planck Hugo Touchette, Erik Van der Straeten, and Wolfram Just

    E-Print Network [OSTI]

    Just, Wolfram

    Brownian motion with dry friction: Fokker-Planck approach Hugo Touchette, Erik Van der Straeten Gennes, in which there is a solid-solid or dry friction force acting on a Brownian particle in addition-dependent Fokker-Planck equation. Exact results are found for the case where only dry friction acts on the particle

  8. Tribology Letters Vol. 10, No. 1-2, 2001 15 Dry friction between flat surfaces: multistable elasticity vs.

    E-Print Network [OSTI]

    Mueser, Martin

    Tribology Letters Vol. 10, No. 1-2, 2001 15 Dry friction between flat surfaces: multistable-Universität, 55099 Mainz, Germany E-mail: martin.mueser@uni-mainz.de A generic model for frictional forces between to finite pinning (static friction) forces are analyzed by varying the geometry, the interfacial interaction

  9. On large deviation properties of Brownian motion with dry friction Yaming Chen 1, # and Wolfram Just 1, +

    E-Print Network [OSTI]

    Just, Wolfram

    On large deviation properties of Brownian motion with dry friction Yaming Chen 1, # and Wolfram with dry friction, including quantitative measures to characterize deviation from Gaussian behaviour to dry friction as an illustrative example where explicit expressions for the distribution of functionals

  10. Texture-induced modulations of friction force: the fingerprint effect E. Wandersman, R. Candelier, G. Debregeas, and A. Prevost

    E-Print Network [OSTI]

    , CNRS FRE 3231, 24 rue Lhomond, 75005 Paris, France (Dated: July 13, 2011) Dry solid friction is oftenTexture-induced modulations of friction force: the fingerprint effect E. Wandersman, R. Candelier characteristics of the substrate. The model's main ingredient is the non-linearity of the friction law. Since

  11. Effect of friction on the force distribution in sheared granular materials A. Singh, V. Magnanimo & S. Luding

    E-Print Network [OSTI]

    Luding, Stefan

    averaging in the steady state. Simulations of dry particles with and without friction have been validatedEffect of friction on the force distribution in sheared granular materials A. Singh, V. Magnanimo of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands. The effect of friction on the quasi

  12. Evaluation of the real contact area in three-body dry friction by micro-thermal analysis

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Evaluation of the real contact area in three-body dry friction by micro- thermal analysis Philippe the real AFM maps. Keywords: Scanning thermal microscopy; Friction; Third body; Greenwood­Williamson approach 1. Introduction Many tribological properties--such as friction and wear--greatly depend on the so

  13. Friction Stir Welding Download the files fswss.txt and fswdyn.txt from the course website. These files contain

    E-Print Network [OSTI]

    Landers, Robert G.

    Friction Stir Welding QUESTION 1 Download the files fswss.txt and fswdyn.txt from the course website. These files contain experimental data from a friction stir welding process of 6061 aluminum 0 2 1 0 F z b z b d z z a z a + = + + (3) #12;Friction Stir Welding QUESTION 2 Download the files

  14. Towards approximate models of coulomb frictional moments in: I) revolute pin joints and II) spherical-socket ball joints

    E-Print Network [OSTI]

    -body contact configuration with various degrees of clearance. The proposed models can be used in the dynamic modelling and control of multi-body systems in frictional contact. Key words: Approximate frictional models and dynamic cases. The motivation for accurate modeling of frictional moments in these types of joints

  15. Diagnosing residual motion via the x-ray self emission from indirectly driven inertial confinement implosions

    SciTech Connect (OSTI)

    Pak, A., E-mail: pak5@llnl.gov; Field, J. E.; Benedetti, L. R.; Caggiano, J.; Hatarik, R.; Izumi, N.; Khan, S. F.; Ma, T.; Spears, B. K.; Town, R. P. J.; Bradley, D. K. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Knauer, J. [Laboratory for Laser Energetics, Rochester, New York 14623 (United States)

    2014-11-15T23:59:59.000Z

    In an indirectly driven implosion, non-radial translational motion of the compressed fusion capsule is a signature of residual kinetic energy not coupled into the compressional heating of the target. A reduction in compression reduces the peak pressure and nuclear performance of the implosion. Measuring and reducing the residual motion of the implosion is therefore necessary to improve performance and isolate other effects that degrade performance. Using the gated x-ray diagnostic, the x-ray Bremsstrahlung emission from the compressed capsule is spatially and temporally resolved at x-ray energies of >8.7 keV, allowing for measurements of the residual velocity. Here details of the x-ray velocity measurement and fitting routine will be discussed and measurements will be compared to the velocities inferred from the neutron time of flight detectors.

  16. Method for measuring residual stresses in materials by plastically deforming the material and interference pattern comparison

    DOE Patents [OSTI]

    Pechersky, Martin J. (241 Chardonnat La., Aiken, SC 29803)

    1995-01-01T23:59:59.000Z

    A method for measuring residual stress in a material comprising the steps of establishing a speckle pattern on the surface with a first laser then heating a portion of that pattern with an infrared laser until the surface plastically deforms. Comparing the speckle patterns before and after deformation by subtracting one pattern from the other will produce a fringe pattern that serves as a visual and quantitative indication of the degree to which the plasticized surface responded to the stress dung heating and enables calculation of the stress.

  17. Thermal input control and enhancement for laser based residual stress measurements using liquid temperature indicating coatings

    DOE Patents [OSTI]

    Pechersky, M.J.

    1999-07-06T23:59:59.000Z

    An improved method for measuring residual stress in a material is disclosed comprising the steps of applying a spot of temperature indicating coating to the surface to be studied, establishing a speckle pattern surrounds the spot of coating with a first laser then heating the spot of coating with a far infrared laser until the surface plastically deforms. Comparing the speckle patterns before and after deformation by subtracting one pattern from the other will produce a fringe pattern that serves as a visual and quantitative indication of the degree to which the plasticized surface responded to the stress during heating and enables calculation of the stress. 3 figs.

  18. Thermal input control and enhancement for laser based residual stress measurements using liquid temperature indicating coatings

    DOE Patents [OSTI]

    Pechersky, Martin J. (Aiken, SC)

    1999-01-01T23:59:59.000Z

    An improved method for measuring residual stress in a material comprising the steps of applying a spot of temperature indicating coating to the surface to be studied, establishing a speckle pattern surrounds the spot of coating with a first laser then heating the spot of coating with a far infrared laser until the surface plastically deforms. Comparing the speckle patterns before and after deformation by subtracting one pattern from the other will produce a fringe pattern that serves as a visual and quantitative indication of the degree to which the plasticized surface responded to the stress during heating and enables calculation of the stress.

  19. San Bernardino District Heating District Heating Low Temperature...

    Open Energy Info (EERE)

    San Bernardino District Heating District Heating Low Temperature Geothermal Facility Facility San Bernardino District Heating Sector Geothermal energy Type District Heating...

  20. Philip District Heating District Heating Low Temperature Geothermal...

    Open Energy Info (EERE)

    Philip District Heating District Heating Low Temperature Geothermal Facility Jump to: navigation, search Name Philip District Heating District Heating Low Temperature Geothermal...

  1. Boise City Geothermal District Heating District Heating Low Temperatur...

    Open Energy Info (EERE)

    Boise City Geothermal District Heating District Heating Low Temperature Geothermal Facility Jump to: navigation, search Name Boise City Geothermal District Heating District Heating...

  2. Pagosa Springs District Heating District Heating Low Temperature...

    Open Energy Info (EERE)

    Pagosa Springs District Heating District Heating Low Temperature Geothermal Facility Jump to: navigation, search Name Pagosa Springs District Heating District Heating Low...

  3. Midland District Heating District Heating Low Temperature Geothermal...

    Open Energy Info (EERE)

    Midland District Heating District Heating Low Temperature Geothermal Facility Facility Midland District Heating Sector Geothermal energy Type District Heating Location Midland,...

  4. Kethcum District Heating District Heating Low Temperature Geothermal...

    Open Energy Info (EERE)

    Kethcum District Heating District Heating Low Temperature Geothermal Facility Jump to: navigation, search Name Kethcum District Heating District Heating Low Temperature Geothermal...

  5. Northeast Home Heating Oil Reserve System Heating Oil, PIA Office...

    Energy Savers [EERE]

    Northeast Home Heating Oil Reserve System Heating Oil, PIA Office of Fossil Energy Headquaters Northeast Home Heating Oil Reserve System Heating Oil, PIA Office of Fossil Energy...

  6. Heat Pump for High School Heat Recovery 

    E-Print Network [OSTI]

    Huang, K.; Wang, H.; Zhou, X.

    2006-01-01T23:59:59.000Z

    The heat pump system used for recycling and reusing waste heat in s high school bathroom was minutely analyzed in its coefficient of performance, onetime utilization ratio of energy, economic property and so on. The results showed that this system...

  7. Industrial Waste Heat Recovery Using Heat Pipes

    E-Print Network [OSTI]

    Ruch, M. A.

    1981-01-01T23:59:59.000Z

    -expanding variety of industrial processes. One notable application in recent years has been for combustion airs preheat of fired heaters in petroleum refineries and petrochemical plants. Another recent development has been a waste heat recovery boiler using heat...

  8. Arabian crude-oil residues evaluated

    SciTech Connect (OSTI)

    Ali, M.F.; Bukhari, A.; Hasan, M.; Saleem, M.

    1985-08-12T23:59:59.000Z

    This article evaluates detailed physical and chemical characteristics for four important Saudi Arabian resids. Petroleum residues are composed of a mixture of large and complex hydrocarbon molecules along with one or more heteroatoms such as sulfur, oxygen, nitrogen, vanadium, and nickel. The amount of residue and its physical and chemical composition depend on the source of the crude oil and methods of processing. Residues from four Saudi Arabian crude oils produced by the Arabian American Oil Co. (Aramco) were evaluated. The crude oils are 38.5 degrees API Arabian Extra Light, 33.8 degrees API Arabian Light, 30.4 degrees Api Arabian Medium, and 28.03 degrees API Arabian Heavy. Results are presented and residue preparation, and physical and chemical characteristics are analyzed.

  9. California: Agricultural Residues Produce Renewable Fuel | Department...

    Broader source: Energy.gov (indexed) [DOE]

    Logos Technologies and EERE partnered with EdeniQ of Visalia, California, to construct a pilot plant that processes 1.2 tons per day of agricultural residues, such as corn stover...

  10. Residual stress in nanocrystalline nickel tungsten electrodeposits

    E-Print Network [OSTI]

    Ziebell, Tiffany D. (Tiffany Dawn)

    2011-01-01T23:59:59.000Z

    Characterizing the residual stress of thick nanocrystalline electrodeposits poses several unique challenges due to their fine grain structure, thickness distribution, and matte surface. We employ a three-dimensional ...

  11. Frictionally induced ignition processes in drop and skid tests

    SciTech Connect (OSTI)

    Dickson, Peter [Los Alamos National Laboratory; Parker, Gary [Los Alamos National Laboratory; Novak, Alan [Los Alamos National Laboratory

    2010-01-01T23:59:59.000Z

    The standard LANL/Pantex drop and skid tests rely on subjective assessment of reaction violence to quantify the response of the charge, and completely miss nonpropagating hot-spot ignition sites. Additionally, large variations in test results have been observed, which we propose is due to a misunderstanding of the basic physical processes that lead to threshold ignition in these tests. The tests have been redesigned to provide control of these mechanisms and to permit direct observation of hot spots at the impact site, allowing us to follow the progression of the outcome as the drop height and ignition source density are varied. The results confirm that frictional interactions between high-melting-point solids are the dominant ignition mechanism, not just at the threshold, but in fact at all realistic drop heights.

  12. Dynamical friction of radio galaxies in galaxy clusters

    E-Print Network [OSTI]

    Biman B. Nath

    2008-04-22T23:59:59.000Z

    The distribution of luminous radio galaxies in galaxy clusters has been observed to be concentrated in the inner region. We consider the role of dynamical friction of massive galaxies ($M\\sim 10^{12.5}$ M$_{\\odot}$), assuming them to be hosts of luminous radio galaxies, and show that beginning with a Navarro-Frenk-White density profile of a cluster of mass $M_{cl}\\sim 10^{15}$ M$_{\\odot}$ of concentration $c\\sim 5$ and collapsing at $z\\sim 1$, the density profile of radio galaxies evolve to a profile of concentration $c \\sim 25$, as observed, in a time scale of $t\\sim 3\\hbox{--}5$ Gyr.

  13. Lateral position detection and control for friction stir systems

    SciTech Connect (OSTI)

    Fleming, Paul (Boulder, CO); Lammlein, David H. (Houston, TX); Cook, George E. (Brentwood, TN); Wilkes, Don Mitchell (Nashville, TN); Strauss, Alvin M. (Nashville, TN); Delapp, David R. (Ashland City, TN); Hartman, Daniel A. (Fairhope, AL)

    2011-11-08T23:59:59.000Z

    Friction stir methods are disclosed for processing at least one workpiece using a rotary tool with rotating member for contacting and processing the workpiece. The methods include oscillating the rotary tool laterally with respect to a selected propagation path for the rotating member with respect to the workpiece to define an oscillation path for the rotating member. The methods further include obtaining force signals or parameters related to the force experienced by the rotary tool at least while the rotating member is disposed at the extremes of the oscillation. The force signals or parameters associated with the extremes can then be analyzed to determine a lateral position of the selected path with respect to a target path and a lateral offset value can be determined based on the lateral position. The lateral distance between the selected path and the target path can be decreased based on the lateral offset value.

  14. The Impact of Organic Friction Modifiers on Engine Oil Tribofilms

    E-Print Network [OSTI]

    Ratoi, Monica; Alghawel, Husam; Suen, Yat Fan; Nelson, Kenneth

    2013-01-01T23:59:59.000Z

    Organic friction modifiers (OFMs) are important additives in the lubrication of machines and especially of car engines where performance improvements are constantly sought-after. Together with zinc dialkyldithiophosphates (ZDDPs) antiwear additives, OFMs have a predominant impact on the tribological behaviour of the lubricant. In the current study, the influence of OFMs on the generation, tribological properties and chemistry of ZDDP tribofilms has been investigated by combining tribological experiments (MTM) with in-situ film thickness measurements through optical interference imaging (SLIM), Alicona profilometry and X-ray photoelectron spectroscopy. OFMs and antiwear additives have been found to competitively react/adsorb on the rubbing ferrous substrates in a tribological contact. The formation and removal (through wear) of tribofilms are dynamic processes which result from the simultaneous interaction of these two additives with the surface of the wear track. By carefully selecting the chemistry of OFMs, ...

  15. Energy conversion device and method of reducing friction therein

    DOE Patents [OSTI]

    Solovyeva, Lyudmila Mikhaylovna; Jansson, Kyle S; Elmoursi, Alaa AbdelAzim; Zhu, Dong; Milner, Robert; Daughterty, Early Eugene; Higdon, Clifton Baxter; Elagamy, Kamel Abdel-Khalik; Hicks, Aaron Michael

    2013-10-08T23:59:59.000Z

    A device configured for converting energy includes a first surface, a second surface configured for moving with respect to the first surface during operation of the device, and a coating disposed on at least one of the first surface and the second surface. The coating includes a first layer of a ceramic alloy represented by the general formula AlMgB.sub.14--X, wherein X is present in an amount of from 0 to 70 parts by weight based on 100 parts by weight of the ceramic alloy and is a doping agent selected from the group of Group IV elements and borides and nitrides thereof, and a second layer disposed on the first layer and including carbon in a gradient concentration. The coating has a hardness of from 10 to 20 GPa and a coefficient of friction of less than or equal to 0.12.

  16. Absorption heat pump system

    DOE Patents [OSTI]

    Grossman, Gershon (Oak Ridge, TN)

    1984-01-01T23:59:59.000Z

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  17. Absorption heat pump system

    DOE Patents [OSTI]

    Grossman, G.

    1982-06-16T23:59:59.000Z

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  18. Locating Heat Recovery Opportunities 

    E-Print Network [OSTI]

    Waterland, A. F.

    1981-01-01T23:59:59.000Z

    Basic concepts of heat recovery are defined as they apply to the industrial community. Methods for locating, ranking, and developing heat recovery opportunities are presented and explained. The needs for useful heat 'sinks' are emphasized as equal...

  19. Locating Heat Recovery Opportunities

    E-Print Network [OSTI]

    Waterland, A. F.

    1981-01-01T23:59:59.000Z

    Basic concepts of heat recovery are defined as they apply to the industrial community. Methods for locating, ranking, and developing heat recovery opportunities are presented and explained. The needs for useful heat 'sinks' are emphasized as equal...

  20. Photovoltaic roof heat flux

    E-Print Network [OSTI]

    Samady, Mezhgan Frishta

    2011-01-01T23:59:59.000Z

    transient the heat transfer model. T h i s required the roofto develop and calibrate heat transfer models to be able toE S station, the heat transfer models described i n sections

  1. Residual Toxicities of Insecticides to Cotton Insects.

    E-Print Network [OSTI]

    Hightower, B. G.; Gaines, J. C.

    1960-01-01T23:59:59.000Z

    Summary Results of experiments conducted to determine leafworm, the salt-marsh caterpillar and the garden the effect of natural or simulated climatic conditions webworm. on the residual toxicities of several chlorinated hydro- carbon... variety of weathering conditions. Based on residual properties alone, toxaphene and dieldrin ranked with endrin and Sevin, but the initial toxicities of dieldrin and endrin to the boll weevil were appreciably greater than those of toxaphene...

  2. Residual Toxicities of Insecticides to Cotton Insects. 

    E-Print Network [OSTI]

    Hightower, B. G.; Gaines, J. C.

    1960-01-01T23:59:59.000Z

    Summary Results of experiments conducted to determine leafworm, the salt-marsh caterpillar and the garden the effect of natural or simulated climatic conditions webworm. on the residual toxicities of several chlorinated hydro- carbon... variety of weathering conditions. Based on residual properties alone, toxaphene and dieldrin ranked with endrin and Sevin, but the initial toxicities of dieldrin and endrin to the boll weevil were appreciably greater than those of toxaphene...

  3. ABSTRACT: Bioenergy Harvesting Technologies to Supply Crop Residues...

    Energy Savers [EERE]

    ABSTRACT: Bioenergy Harvesting Technologies to Supply Crop Residues In a Densified Large Square Bale Format ABSTRACT: Bioenergy Harvesting Technologies to Supply Crop Residues In a...

  4. Woven heat exchanger

    DOE Patents [OSTI]

    Piscitella, R.R.

    1984-07-16T23:59:59.000Z

    This invention relates to a heat exchanger for waste heat recovery from high temperature industrial exhaust streams. In a woven ceramic heat exchanger using the basic tube-in-shell design, each heat exchanger consisting of tube sheets and tube, is woven separately. Individual heat exchangers are assembled in cross-flow configuration. Each heat exchanger is woven from high temperature ceramic fiber, the warp is continuous from tube to tube sheet providing a smooth transition and unitized construction.

  5. Total Space Heat-

    Annual Energy Outlook 2013 [U.S. Energy Information Administration (EIA)]

    Commercial Buildings Energy Consumption Survey: Energy End-Use Consumption Tables Total Space Heat- ing Cool- ing Venti- lation Water Heat- ing Light- ing Cook- ing Refrig- eration...

  6. Total Space Heat-

    Gasoline and Diesel Fuel Update (EIA)

    Revised: December, 2008 Total Space Heat- ing Cool- ing Venti- lation Water Heat- ing Light- ing Cook- ing Refrig- eration Office Equip- ment Com- puters Other All Buildings...

  7. Ultra low friction carbon/carbon composites for extreme temperature applications

    DOE Patents [OSTI]

    Erdemir, Ali (Naperville, IL); Busch, Donald E. (Hinsdale, IL); Fenske, George R. (Downers Grove, IL); Lee, Sam (Gardena, CA); Shepherd, Gary (Los Alamitos, CA); Pruett, Gary J. (Cypress, CA)

    2001-01-01T23:59:59.000Z

    A carbon/carbon composite in which a carbon matrix containing a controlled amount of boron or a boron compound is reinforced with carbon fiber exhibits a low coefficient of friction, i.e., on the order of 0.04 to 0.1 at temperatures up to 600.degree. C., which is one of the lowest frictional coefficients for any type of carbonaceous material, including graphite, glassy carbon, diamond, diamond-like carbon and other forms of carbon material. The high degree of slipperiness of the carbon composite renders it particularly adapted for limiting friction and wear at elevated temperatures such as in seals, bearings, shafts, and flexible joints

  8. A frictional model of a two-port unbounded ocean basin

    E-Print Network [OSTI]

    Wert, Richard Thomas

    1968-01-01T23:59:59.000Z

    A FRICTIONAL MODEL OF A TWO-PORT UNBOUNDED OCEAN BASIN A Thesis by RICHARD T. WERT Submitted to the Graduate College of the Texas AE M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1968 Major... Subject: Physical Oceanography A FRICTIONAL MODEL OF A TWO-PORT UNBOUNDED OCEAN BASIN A Thesis by RICHARD T. WERT Approved as to style and content by: (Chairxnan of Coxnxnittee) (Head of the Departxnent) (M her) (Mexnber) May 1968 A Frictional...

  9. Investigation of wall friction in noncircular ducts with a rough liner

    E-Print Network [OSTI]

    Tyler, John Charles

    1959-01-01T23:59:59.000Z

    section Density Viscosity Dimensions L5/Q L/Q m/L& m/LQ 1. The friction factors, Reynolds numbers, and. abso- lute roughnesses for fluid flow in ducts having a glass fiber liner have been calculated and plotted in the form of characteristic... distributed, it is essential that the wall friction phenomena associated with the particular duct design be understood. When fluid is passed through a duct, a static pressure drop occurs due to the friction forces which act between the fluid. particles...

  10. Friction Makes the World Go Round Even though there are many physical things that make everyday life possible, few are more important than

    E-Print Network [OSTI]

    Roy, Subrata

    Friction Makes the World Go Round K.G. Rowe Even though there are many physical things that make everyday life possible, few are more important than friction. Friction allows us to walk, drive cars or drive on really slick ice--this would be the case in a world without friction. The Study of Tire Rubber

  11. Duhem Models for Hysteresis in Sliding and Presliding Friction* JinHyoung Oh, Ashwani K. Padthe, Dennis S. Bernstein, Demosthenis D. Rizos, and Spilios D. Fassois

    E-Print Network [OSTI]

    Sontag, Eduardo

    , namely, Coulomb friction, is discontinuous. Discontinuous dry friction models are studied in [15]. Some is challenging since some models involve nonsmooth dynamics. For example, the most widely used dry friction modelDuhem Models for Hysteresis in Sliding and Presliding Friction* JinHyoung Oh, Ashwani K. Padthe

  12. INITIAL DEVELOPMENT OF A VARIABLE-FRICTION FLOOR SURFACE Guillaume Millet, Martin J.-D. Otis, Gary Chaw, Jeremy R. Cooperstock

    E-Print Network [OSTI]

    Cooperstock, Jeremy R.

    ). An- other is by changing dry friction into lubricated friction, that is, placing a lubricant quantified with Coulomb's model; examples of coefficients of static friction are 0.04 for PTFE/PTFE contactINITIAL DEVELOPMENT OF A VARIABLE-FRICTION FLOOR SURFACE Guillaume Millet, Martin J.-D. Otis, Gary

  13. Sustainable System for Residual Hazards Management

    SciTech Connect (OSTI)

    Kevin M. Kostelnik; James H. Clarke; Jerry L. Harbour

    2004-06-01T23:59:59.000Z

    Hazardous, radioactive and other toxic substances have routinely been generated and subsequently disposed of in the shallow subsurface throughout the world. Many of today’s waste management techniques do not eliminate the problem, but rather only concentrate or contain the hazardous contaminants. Residual hazards result from the presence of hazardous and/or contaminated material that remains on-site following active operations or the completion of remedial actions. Residual hazards pose continued risk to humans and the environment and represent a significant and chronic problem that require continuous longterm management (i.e. >1000 years). To protect human health and safeguard the natural environment, a sustainable system is required for the proper management of residual hazards. A sustainable system for the management of residual hazards will require the integration of engineered, institutional and land-use controls to isolate residual contaminants and thus minimize the associated hazards. Engineered controls are physical modifications to the natural setting and ecosystem, including the site, facility, and/or the residual materials themselves, in order to reduce or eliminate the potential for exposure to contaminants of concern (COCs). Institutional controls are processes, instruments, and mechanisms designed to influence human behavior and activity. System failure can involve hazardous material escaping from the confinement because of system degradation (i.e., chronic or acute degradation) or by externalintrusion of the biosphere into the contaminated material because of the loss of institutional control. An ongoing analysis of contemporary and historic sites suggests that the significance of the loss of institutional controls is a critical pathway because decisions made during the operations/remedial action phase, as well as decisions made throughout the residual hazards management period, are key to the longterm success of the prescribed system. In fact, given that society has become more reliant on and confident of engineered controls, there may be a growing tendency to be even less concerned with institutional controls.

  14. Microstructural Examination to Aid in Understanding Friction Bonding Fabrication Technique for Monolithic Nuclear Fuel

    SciTech Connect (OSTI)

    Karen L. Shropshire

    2008-04-01T23:59:59.000Z

    Monolithic nuclear fuel is currently being developed for use in research reactors, and friction bonding (FB) is a technique being developed to help in this fuel’s fabrication. Since both FB and monolithic fuel are new concepts, research is needed to understand the impact of varying FB fabrication parameters on fuel plate characteristics. This thesis research provides insight into the FB process and its application to the monolithic fuel design by recognizing and understanding the microstructural effects of varying fabrication parameters (a) FB tool load, and (b) FB tool face alloy. These two fabrication parameters help drive material temperature during fabrication, and thus the material properties, bond strength, and possible formation of interface reaction layers. This study analyzed temperatures and tool loads measured during those FB processes and examined microstructural characteristics of materials and bonds in samples taken from the resulting fuel plates. This study shows that higher tool load increases aluminum plasticization and forging during FB, and that the tool face alloy helps determine the tool’s heat extraction efficacy. The study concludes that successful aluminum bonds can be attained in fuel plates using a wide range of FB tool loads. The range of tool loads yielding successful uranium-aluminum bonding was not established, but it was demonstrated that such bonding can be attained with FB tool load of 48,900 N (11,000 lbf) when using a FB tool faced with a tungsten alloy. This tool successfully performed FB, and with better results than tools faced with other materials. Results of this study correlate well with results reported for similar aluminum bonding techniques. This study’s results also provide support and validation for other nuclear fuel development studies and conclusions. Recommendations are offered for further research.

  15. Study of local heat/mass transfer distributions in multipass channels for turbine blade cooling

    SciTech Connect (OSTI)

    Chandra, P.R.

    1987-01-01T23:59:59.000Z

    The heat transfer and friction characteristics of turbulent air flow in a two-pass square channel were experimentally investigated via the naphthalene sublimation technique. The test section, which consists of two straight square channels joined by a sharp 180/sup 0/ turn, simulates the internal cooling passages of gas-turbine airfoils. The top and bottom surfaces of the test channel were roughened by rib turbulators. The effects of Reynolds number (between 10,000 and 60,000), rib pitch-to-height ratio (P/e = 10 and 20), rib height-to-hydraulic diameter ratio (e/D = 0.063 and 0.094) and rib angle-of-attack (..cap alpha.. = 90/sup 0/, 60/sup 0/ and 45/sup 0/) were studied. The local heat transfer coefficients were measured both on the ribbed side walls and on the smooth side walls along the channel. The friction factors in the before-turn, in-turn, and after-turn regions were also calculated. Average Sherwood number ratios and average friction results were correlated and compared with the published heat transfer and pressure drop data.

  16. Validated heat-transfer and pressure-drop prediction methods based on the discrete-element method: Phase 2, two-dimensional rib roughness

    SciTech Connect (OSTI)

    James, C.A.; Hodge, B.K.; Taylor, R.P. [Mississippi State Univ., MS (United States). Dept. of Mechanical and Nuclear Engineering

    1993-05-01T23:59:59.000Z

    Surface roughness is a commonly used approach for enhancing the rate of heat transfer of surfaces, such as in heat-exchanger tubes. Because the improved thermal performance of roughened surfaces is at the expense of increased flow resistance (increased pressure drop or friction factor), accurate prediction techniques for determining the friction factors and Nusselt numbers for roughened surfaces are required if such features are to be considered as design options. This report presents the results of the second phase of a research program sponsored by Argonne National Laboratory to validate models for the prediction of friction factors and Nusselt numbers for fully developed turbulent flow in enhanced heat-exchanger tubes. The first phase was concerned with validating a roughness model for turbulent flow in tubes internally roughened with three-dimensional distributed roughness elements, such as sandgrains, spheres, hemispheres, and cones. The second phase is concerned with devising and validating methods for the prediction of friction factors and Nusselt numbers for turbulent flow in tubes internally roughened with repeated, two-dimensional ribs aligned perpendicular to the flow. The ribs are spaced sufficiently far apart that the leeward-side separated flow reattaches to the wall before again separating in order to negotiate the next rib. This heat-transfer enhancement mechanism is called the separation and reattachment mechanism, after Rabas (1989). This work is limited to rectangular rib shapes.

  17. Effect of heat treatment temperature on nitinol wire

    SciTech Connect (OSTI)

    Cai, S.; Schaffer, J. E. [Fort Wayne Metals Research Products Corporation, 9609 Ardmore Ave., Fort Wayne, Indiana 46809 (United States); Daymond, M. R. [Department of Mechanical and Materials Engineering, Queen's University, Nicol Hall, 60 Union Street, Kingston, Ontario K7L 3N6 (Canada); Yu, C. [State Key Laboratory of Heavy Oil Processing, China University of Petroleum, 102249 Beijing (China); Ren, Y. [Argonne National Laboratory, 9700 S. Cass Ave, 433/D008, Argonne, Illinois 60439 (United States)

    2014-08-18T23:59:59.000Z

    In-situ synchrotron X-ray diffraction has been used to study the influence of the heat treatment temperature on the subsequent micromechanical behavior of nitinol wire. It was found that increase in the heat treatment temperature rotated the austenite texture from the (332){sub B2} fiber towards the (111){sub B2} fiber, and the texture of the Stress-Induced Martensite phase changed from the (1{sup ¯}40){sub B19'} to the (1{sup ¯}20){sub B19'} fiber accordingly. Heat treatment at a low temperature reduces the internal residual strains in the austenite during super-elastic deformation and therefore improves the materials fatigue performance. The development of internal residual strains in austenite is controlled by transformation induced plasticity and the reversal martensite to austenite transformation.

  18. Rotary magnetic heat pump

    DOE Patents [OSTI]

    Kirol, Lance D. (Shelly, ID)

    1988-01-01T23:59:59.000Z

    A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation.

  19. Rotary magnetic heat pump

    DOE Patents [OSTI]

    Kirol, L.D.

    1987-02-11T23:59:59.000Z

    A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation. 5 figs.

  20. Mass and Heat Recovery 

    E-Print Network [OSTI]

    Hindawai, S. M.

    2010-01-01T23:59:59.000Z

    In the last few years heat recovery was under spot and in air conditioning fields usually we use heat recovery by different types of heat exchangers. The heat exchanging between the exhaust air from the building with the fresh air to the building...

  1. BY HOW MUCH CAN RESIDUAL MINIMIZATION ACCELERATE THE CONVERGENCE OF ORTHOGONAL RESIDUAL METHODS?

    E-Print Network [OSTI]

    Gutknecht, Martin H.

    . Examples of such pairs are the conjugate gradient (CG) and the conjugate residual (CR) methods, the full-minimal residual (QMR) methods. Also the pairs consisting of the (bi)conjugate gradient squared (CGS, iterative method, Krylov space method, conjugate gradient method, biconjugate gradient method, CG, CGNE

  2. Assessing the frictional and baroclinic contributions to stratified wake formation: a parameter space study 

    E-Print Network [OSTI]

    Smith, Jamie Brooke

    2006-08-16T23:59:59.000Z

    The baroclinic and surface-frictional contributions to stratified wake formation are considered as a function of the non-dimensional height ( = Nho/U) and aspect-ratio ( = ho/L) of the barrier. Numerical simulations are ...

  3. Internal friction and absence of dilatancy of packings of frictionless polygons

    E-Print Network [OSTI]

    Radjai, Franck

    By means of numerical simulations, we show that assemblies of frictionless rigid pentagons in slow shear flow possess an internal friction coefficient (equal to 0.183 ± 0.008 with our choice of moderately polydisperse ...

  4. Exact solutions to the compressible Navier-Stokes equations with the Coriolis and friction terms

    E-Print Network [OSTI]

    Korshunova, Anastasya

    2008-01-01T23:59:59.000Z

    We consider special solution to the 3D compressible Navier-Stokes system with and without the Coriolis force and dry friction and find the respective initial data implying a finite time gradient catastrophe.

  5. Low-Engine-Friction Technology for Advanced Natural-Gas Reciprocating Engines

    SciTech Connect (OSTI)

    Victor Wong; Tian Tian; G. Smedley; L. Moughon; Rosalind Takata; J. Jocsak

    2006-11-30T23:59:59.000Z

    This program aims at improving the efficiency of advanced natural-gas reciprocating engines (ANGRE) by reducing piston and piston ring assembly friction without major adverse effects on engine performance, such as increased oil consumption and wear. An iterative process of simulation, experimentation and analysis has been followed towards achieving the goal of demonstrating a complete optimized low-friction engine system. In this program, a detailed set of piston and piston-ring dynamic and friction models have been adapted and applied that illustrate the fundamental relationships among mechanical, surface/material and lubricant design parameters and friction losses. Demonstration of low-friction ring-pack designs in the Waukesha VGF 18GL engine confirmed ring-pack friction reduction of 30-40%, which translates to total engine FEMP (friction mean effective pressure) reduction of 7-10% from the baseline configuration without significantly increasing oil consumption or blow-by flow. The study on surface textures, including roughness characteristics, cross hatch patterns, dimples and grooves have shown that even relatively small-scale changes can have a large effect on ring/liner friction, in some cases reducing FMEP by as much as 30% from a smooth surface case. The measured FMEP reductions were in good agreement with the model predictions. The combined analysis of lubricant and surface design indicates that low-viscosity lubricants can be very effective in reducing friction, subject to component wear for extremely thin oils, which can be mitigated with further lubricant formulation and/or engineered surfaces. Hence a combined approach of lubricant design and appropriate wear reduction offers improved potential for minimum engine friction loss. Testing of low-friction lubricants showed that total engine FMEP reduced by up to {approx}16.5% from the commercial reference oil without significantly increasing oil consumption or blow-by flow. Piston friction studies indicate that a flatter piston with a more flexible skirt, together with optimizing the waviness and film thickness on the piston skirt offer significant friction reduction. Combined with low-friction ring-pack, material and lubricant parameters, a total power cylinder friction reduction of 30-50% is expected, translating to an engine efficiency increase of two percentage points from its current baseline towards the goal of 50% ARES engine efficiency. The design strategies developed in this study have promising potential for application in all modern reciprocating engines as they represent simple, low-cost methods to extract significant fuel savings. The current program has possible spinoffs and applications in other industries as well, including transportation, CHP, and diesel power generation. The progress made in this program has wide engine efficiency implications, and potential deployment of low-friction engine components or lubricants in the near term is quite possible.

  6. Kinetic and Friction Head Loss Impacts on Horizontal Water Supply and Aquifer Storage and Recovery Wells 

    E-Print Network [OSTI]

    Blumenthal, Benjamin

    2014-12-02T23:59:59.000Z

    well construction or intra-wellbore head loss. Currently no analytical groundwater model rigorously accounts for intra-wellbore kinetic and friction head loss. We have developed a semi-analytical, intra-wellbore head loss model dynamically linked...

  7. Rest-to-Rest Motion of an Experimental Flexible Structure subject to Friction: Linear Programming

    E-Print Network [OSTI]

    Singh, Tarunraj

    and robot arm position- ing. Velocity control is also relevant in machine tool, disk drive and robot arm of controllers in this area include high precision overhead robot arms subject to friction at the joints, high

  8. Micro and nano mechanics of materials response during instrumented frictional sliding

    E-Print Network [OSTI]

    Bellemare, Simon C. (Simon Claude)

    2006-01-01T23:59:59.000Z

    Over the past decade, many computational studies have explored the mechanics of instrumented normal indentation. In contrast, very few studies have investigated quantitative aspects of frictional sliding contact in the ...

  9. Transition from static to kinetic friction: Insights from a 2D model

    E-Print Network [OSTI]

    Trømborg, Jørgen; Amundsen, David Skålid; Thøgersen, Kjetil; Malthe-Sørenssen, Anders

    2013-01-01T23:59:59.000Z

    We describe a 2D spring-block model for the transition from static to kinetic friction at an elastic slider/rigid substrate interface obeying a minimalistic friction law (Amontons-Coulomb). By using realistic boundary conditions, a number of previously unexplained experimental results on precursory micro-slip fronts are successfully reproduced. From the analysis of the interfacial stresses, we derive a prediction for the evolution of the precursor length as a function of the applied loads, as well as an approximate relationship between microscopic and macroscopic friction coefficients. We show that the stress build-up due to both elastic loading and micro-slip-related relaxations depend only weakly on the underlying shear crack propagation dynamics. Conversely, crack speed depends strongly on both the instantaneous stresses and the friction coefficients, through a non-trivial scaling parameter.

  10. Experimental investigation of energy dissipation behavior of the modified friction device

    E-Print Network [OSTI]

    Zahner, Robert Marne

    2011-01-01T23:59:59.000Z

    As building materials become stronger, dynamic design and structural control are effective means of improving serviceability in the future's ever lighter structures. The recently proposed modified friction device (MFD) ...

  11. In situ control of lubricant properties for reduction of power cylinder friction through thermal barrier coating

    E-Print Network [OSTI]

    Molewyk, Mark Allen

    2014-01-01T23:59:59.000Z

    Lowering lubricant viscosity to reduce friction generally carries a side effect of increased metal-metal contact in mixed or boundary lubrication, for example near top ring reversal along the engine cylinder liner. A ...

  12. Defining the role of elastic lubricants and micro textured surfaces in lubricated, sliding friction

    E-Print Network [OSTI]

    Hupp, Sara J. (Sara Jean), 1979-

    2008-01-01T23:59:59.000Z

    Solutions for reducing friction in sliding, lubricated systems include modifying lubricant rheology using polymers and adding a micro-scale texture to the sliding surfaces, but the mechanism of how lubrication properties ...

  13. Thulium-170 heat source

    DOE Patents [OSTI]

    Walter, Carl E. (Pleasanton, CA); Van Konynenburg, Richard (Livermore, CA); VanSant, James H. (Tracy, CA)

    1992-01-01T23:59:59.000Z

    An isotopic heat source is formed using stacks of thin individual layers of a refractory isotopic fuel, preferably thulium oxide, alternating with layers of a low atomic weight diluent, preferably graphite. The graphite serves several functions: to act as a moderator during neutron irradiation, to minimize bremsstrahlung radiation, and to facilitate heat transfer. The fuel stacks are inserted into a heat block, which is encased in a sealed, insulated and shielded structural container. Heat pipes are inserted in the heat block and contain a working fluid. The heat pipe working fluid transfers heat from the heat block to a heat exchanger for power conversion. Single phase gas pressure controls the flow of the working fluid for maximum heat exchange and to provide passive cooling.

  14. Thermoelectric heat exchange element

    DOE Patents [OSTI]

    Callas, James J. (Peoria, IL); Taher, Mahmoud A. (Peoria, IL)

    2007-08-14T23:59:59.000Z

    A thermoelectric heat exchange module includes a first substrate including a heat receptive side and a heat donative side and a series of undulatory pleats. The module may also include a thermoelectric material layer having a ZT value of 1.0 or more disposed on at least one of the heat receptive side and the heat donative side, and an electrical contact may be in electrical communication with the thermoelectric material layer.

  15. Mass and Heat Recovery

    E-Print Network [OSTI]

    Hindawai, S. M.

    2010-01-01T23:59:59.000Z

    - 1 - MASS AND HEAT RECOVERY SYSTEM SALAH MAHMOUD HINDAWI DIRECTOR HINDAWI FOR ENGINEERING SERVICES & CONTRACTING NEW DAMIETTA , EGYPT ABSTRACT : In the last few years heat recovery was under spot . and in air conditioning fields... ) as a heat recovery . and I use the water as a mass recovery . The source of mass and heat recovery is the condensate water which we were dispose and connect it to the drain lines . THE BENEFIT OF THIS SYSTEM ARE : 1) Using the heat energy from...

  16. Friction welded nonconsumable electrode assembly and use thereof for electrolytic production of metals and silicon

    DOE Patents [OSTI]

    Byrne, Stephen C. (Monroeville, PA); Ray, Siba P. (Pittsburgh, PA); Rapp, Robert A. (Columbus, OH)

    1984-01-01T23:59:59.000Z

    A nonconsumable electrode assembly suitable for use in the production of metal by electrolytic reduction of a metal compound dissolved in a molten salt, the assembly comprising a metal conductor and a ceramic electrode body connected by a friction weld between a portion of the body having a level of free metal or metal alloy sufficient to effect such a friction weld and a portion of the metal conductor.

  17. Friction stir welding and processing of oxide dispersion strengthened (ODS) alloys

    DOE Patents [OSTI]

    Ren, Weiju

    2014-11-11T23:59:59.000Z

    A method of welding including forming a filler material of a first oxide dispersoid metal, the first oxide dispersoid material having first strengthening particles that compensate for decreases in weld strength of friction stir welded oxide dispersoid metals; positioning the filler material between a first metal structure and a second metal structure each being comprised of at least a second oxide dispersoid metal; and friction welding the filler material, the first metal structure and the second metal structure to provide a weld.

  18. The measurement of contact areas and temperature during frictional sliding of Tennessee sandstone 

    E-Print Network [OSTI]

    Teufel, Lawrence William

    1976-01-01T23:59:59.000Z

    THE MEASUREMENT OF CONTACT AREAS AND TEMPERATURE DURING FRICTIONAL SLIDING OF TENNESSEE SANDSTONE A Thesis by LAWRENCE WILLIAM TEUFEL Submit';ed to the Graduate College of Texas ASM University in partial fulfillment of the requirements... for the degree of MASTERS OF SCIENCE August 1976 Major Subiect: Geology THE MEASUREMENT OF CONTACT AREAS AND TEMPERATURES DURING FRICTIONAL SLIDING OF TENNESSEE SANDSTONE A Thesis by LAWRENCE WILLIAM TEUFEL Approved as to sty1e and content by: Cha rma...

  19. Frictional characteristics of serpentinite from the Motagua fault zone in Guatemala: an experimental study 

    E-Print Network [OSTI]

    Dengo, Carlos Arturo

    1978-01-01T23:59:59.000Z

    of the requirement for the degree of MASTER OF SCIENCE December 1978 Mad or Subjec' . " Geology FRICTIONAL CHARACTERISTIC OF SERPENTINITF. FRON THE I", OTAGUA FAULT ZONE Ili GUATENALA: AN EXPERIMENTAL STUDY A Thesis by CARLOS ARTURO DFNGO App", oved... strike-slip, seismogenic faults warrants a systematic i nvesti ga tion to determine ho v it". frictional characteristics may afreet slip along the fault. Five locations aiong the fault zone were sampled to investigate the sliding !rode as a function...

  20. Frictional properties between fine grained limestone, dolomite and sandstone along precut surfaces 

    E-Print Network [OSTI]

    Iwasaki, Takeshi

    1970-01-01T23:59:59.000Z

    characteristic parallel lines upon its surface in the direction of slid- ing. If the two materials are the same, both surfaces flow equally, and mutual adhesion and welding occur at the points of contact. In the latter case, frictional work is required... FRICTIONAL PROPERTIES BETNEEN FINE GRAINED I, IMESTONE, DOLOMI"'E AND SANDSTONE ALONG PRECUT SURFACFS A Thesis TAKESHI INASAKI Submitted to the Graduate College of Texas MN University in partial fulfillment of the requirements for the degree...