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1

Comparison of Frictional Heating Models  

SciTech Connect (OSTI)

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.

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

2013-10-01T23:59:59.000Z

2

Friction-Induced Fluid Heating in Nanoscale Helium Flows  

SciTech Connect (OSTI)

We investigate the mechanism of friction-induced fluid heating in nanoconfinements. Molecular dynamics simulations are used to study the temperature variations of liquid helium in nanoscale Poiseuille flows. It is found that the fluid heating is dominated by different sources of friction as the external driving force is changed. For small external force, the fluid heating is mainly caused by the internal viscous friction in the fluid. When the external force is large and causes fluid slip at the surfaces of channel walls, the friction at the fluid-solid interface dominates over the internal friction in the fluid and is the major contribution to fluid heating. An asymmetric temperature gradient in the fluid is developed in the case of nonidentical walls and the general temperature gradient may change sign as the dominant heating factor changes from internal to interfacial friction with increasing external force.

Li Zhigang [Department of Mechanical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

2010-05-21T23:59:59.000Z

3

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

E-Print Network [OSTI]

Friction and Heat Transfer Characteristics of Silica and CNT Nanofluids in a Tube Flow MILIVOJE M@niu.edu * www.kostic.niu.edu Abstract: - An apparatus for exploring friction and heat transfer characteristics flow. Initial turbulent friction and heat transfer measurements for silica and carbon nanotube (CNT

Kostic, Milivoje M.

4

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

SciTech Connect (OSTI)

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.

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

2011-01-01T23:59:59.000Z

5

Quantum Lubrication: Suppression of Friction in a First Principle Four Stroke Heat Engine  

E-Print Network [OSTI]

A quantum model of a heat engine resembling the Otto cycle is employed to explore strategies to suppress frictional losses. These losses are caused by the inability of the engine's working medium to follow adiabatically the change in the Hamiltonian during the expansion and compression stages. By adding external noise to the engine, frictional losses can be suppressed.

Tova Feldmann; Ronnie Kosloff

2005-09-19T23:59:59.000Z

6

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

E-Print Network [OSTI]

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

Kandlikar, Satish

7

Determination of heat transfer and friction characteristics of an adapted inclined louvered fin  

SciTech Connect (OSTI)

An experimental study of a fin-and-tube heat exchanger was performed. To this end a test rig was constructed to measure the heat transfer rate on the air and waterside of the heat exchanger. A wide range of Reynolds numbers on the airside was investigated. The resulting data was used to determine the convective heat transfer correlation (expressed using the Colburn factor) and the friction factor on the airside. The fin type used in the heat exchanger of this research is an adaptation of the standard inclined louvered type. A thorough error analysis was performed, to validate the results. (author)

T'Joen, C.; Steeman, H.-J.; Willockx, A.; De Paepe, M. [Department of Flow, Heat and Combustion Mechanics, Ghent University-UGent, Sint-Pietersnieuwstraat 41, 9000 Gent (Belgium)

2006-03-01T23:59:59.000Z

8

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

SciTech Connect (OSTI)

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.

Ortega, A.; Glowka, D.A.

1982-06-01T23:59:59.000Z

9

Nuclear reactor heat transport system component low friction support system  

DOE Patents [OSTI]

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.

Wade, Elman E. (Ruffs Dale, PA)

1980-01-01T23:59:59.000Z

10

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

E-Print Network [OSTI]

walls 83 66 Ribbed side Nusselt number ratio versus friction factor ratio for broken ribs on one wall 84 67 Smooth side Nusselt number ratio versus friction factor ratio for broken ribs on one wall . , 68 Ribbed side Nusselt number ratio versus... on one wall . 95 96 97 INTRODUCTION Early heat transfer study shows that roughening the surface is an effective way to enhance the heat transfer from a surface. Modern turbine design applies turbulence promoters/ribs inside cooling passages...

Huang, Jie Joy

1991-01-01T23:59:59.000Z

11

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

SciTech Connect (OSTI)

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.

Ortega, A.; Glowka, D.A.

1982-01-01T23:59:59.000Z

12

J. Materials Science, 37, 3965-3972 (2002) Author prepared reprint Experimental Verification of the Effects of Friction and Residual Stress on the  

E-Print Network [OSTI]

were done on AS4 carbon fiber/epoxy and E-glass/epoxy specimens. Using a new interpretation for carbon-fiber/epoxy and 120 J/m2 for glass-fiber/epoxy. Keywords: Interfacial, Friction, Energy Method, Fragmentation Test, Single Fiber Composites, Carbon Fiber, Glass Fiber, Residual Stresses Introduction

Nairn, John A.

13

Evaporation heat transfer and friction characteristics of R-134a flowing downward in a vertical corrugated tube  

SciTech Connect (OSTI)

Differently from most previous studies, the heat transfer and friction characteristics of the pure refrigerant HFC-134a during evaporation inside a vertical corrugated tube are experimentally investigated. The double tube test sections are 0.5 m long with refrigerant flowing in the inner tube and heating water flowing in the annulus. The inner tubes are one smooth tube and two corrugated tubes, which are constructed from smooth copper tube of 8.7 mm inner diameter. The test runs are performed at evaporating temperatures of 10, 15, and 20 C, heat fluxes of 20, 25, and 30 kW/m{sup 2}, and mass fluxes of 200, 300, and 400 kg/m{sup 2} s. The quality of the refrigerant in the test section is calculated using the temperature and pressure obtained from the experiment. The pressure drop across the test section is measured directly by a differential pressure transducer. The effects of heat flux, mass flux, and evaporation temperature on the heat transfer coefficient and two-phase friction factor are also discussed. It is found that the percentage increases of the heat transfer coefficient and the two-phase friction factor of the corrugated tubes compared with those of the smooth tube are approximately 0-10% and 70-140%, respectively. (author)

Aroonrat, Kanit; Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, King Mongkut's University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand)

2011-01-15T23:59:59.000Z

14

Experimental investigation on heat transfer and frictional characteristics of vertical upward rifled tube in supercritical CFB boiler  

SciTech Connect (OSTI)

Water wall design is a key issue for supercritical Circulating Fluidized Bed (CFB) boiler. On account of the good heat transfer performance, rifled tube is applied in the water wall design of a 600 MW supercritical CFB boiler in China. In order to investigate the heat transfer and frictional characteristics of the rifled tube with vertical upward flow, an in-depth experiment was conducted in the range of pressure from 12 to 30 MPa, mass flux from 230 to 1200 kg/(m{sup 2} s), and inner wall heat flux from 130 to 720 kW/m{sup 2}. The wall temperature distribution and pressure drop in the rifled tube were obtained in the experiment. The normal, enhanced and deteriorated heat transfer characteristics were also captured. In this paper, the effects of pressure, inner wall heat flux and mass flux on heat transfer characteristics are analyzed, the heat transfer mechanism and the frictional resistance performance are discussed, and the corresponding empirical correlations are presented. The experimental results show that the rifled tube can effectively prevent the occurrence of departure from nucleate boiling (DNB) and keep the tube wall temperature in a permissible range under the operating condition of supercritical CFB boiler. (author)

Yang, Dong; Pan, Jie; Zhu, Xiaojing; Bi, Qincheng; Chen, Tingkuan [State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049 (China); Zhou, Chenn Q. [Department of Mechanical Engineering, Purdue University Calumet, Hammond, IN 46323 (United States)

2011-02-15T23:59:59.000Z

15

Transient Heat and Material Flow Modeling of Friction Stir Processing of Magnesium Alloy using Threaded Tool  

SciTech Connect (OSTI)

A three-dimensional transient computational fluid dynamics (CFD) model was developed to investigate the material flow and heat transfer during friction stir processing (FSP) in an AZ31B magnesium alloy. The material was assumed to be a non-Newtonian viscoplastic fluid, and the Zener-Hollomon parameter was used to describe the dependence of material viscosity on temperature and strain rate. The material constants used in the constitutive equation were determined experimentally from compression tests of the AZ31B Mg alloy under a wide range of strain rates and temperatures. A dynamic mesh method, combining both Lagrangian and Eulerian formulations, was used to capture the material flow induced by the movement of the threaded tool pin. Massless inert particles were embedded in the simulation domain to track the detailed history of material flow. The actual FSP was also carried out on a wrought Mg plate where temperature profiles were recorded by embedding thermocouples. The predicted transient temperature history was found to be consistent with that measured during FSP. Finally, the influence of the thread on the simulated results of thermal history and material flow was studied by comparing two models: one with threaded pin and the other with smooth pin surface.

Yu, Zhenzhen [ORNL; Zhang, Wei [ORNL; Choo, Hahn [ORNL; Feng, Zhili [ORNL

2012-01-01T23:59:59.000Z

16

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

SciTech Connect (OSTI)

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.

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

2009-01-01T23:59:59.000Z

17

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

E-Print Network [OSTI]

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...

Spence, Rodney Brian

1995-01-01T23:59:59.000Z

18

Nuclear reactor with makeup water assist from residual heat removal system  

DOE Patents [OSTI]

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.

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

1993-01-01T23:59:59.000Z

19

Nuclear reactor with makeup water assist from residual heat removal system  

DOE Patents [OSTI]

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.

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

1993-12-07T23:59:59.000Z

20

Effects of Post-Weld Heat Treatment on the Mechanical Properties of Similar- and Dissimilar-Alloy Friction Stir Welded Blanks  

SciTech Connect (OSTI)

Friction stir welding is a solid state joining process with relatively low welding temperatures. Nevertheless, the mechanical properties of friction stir welded blanks are degraded after welding. Indeed, both strength and ductility of the welds are decreased after welding. Often, the resulting friction stir welded blanks need to be formed to their final structural shape. Therefore, the formability of friction stir welded blanks is of primary importance in the manufacturing of structural parts. This paper studies how the mechanical properties and particularly formability of friction stir welded blanks can be improved by applying a post weld heat treatment. Two aluminum alloys from 2000 and 7000 series, namely 2024-T3 and 7075-T6, are selected for the study. The sheet thickness of both materials is 2,0 mm. The selected alloys are welded in three configurations: 2024-T3 and 2024-T3, 7075-T6 and 7075-T6, and 2024-T3 and 7075-T6. The resulting welds are naturally aged for a few months. Three sets of standard dog bone shape tensile test specimens are then machined from the welds. The first set of the specimens is tested without any heat treatment. The second set of the specimens is solution heat treated and quenched before testing. The third set of the specimens is solution heat treated, quenched, and naturally aged for a week before testing. The mechanical properties of the three different sets of specimens are compared with each other. It is shown that careful selection of post weld heat-treatment can greatly improve the formability of friction stir welded blanks.

Zadpoor, Amir Abbas [Materials Innovation Institute (M2i), Mekelweg 2, Delft 2628CD (Netherlands); Faculty of Aerospace Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft 2629HS (Netherlands); Sinke, Jos [Faculty of Aerospace Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft 2629HS (Netherlands)

2011-01-17T23:59:59.000Z

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

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

SciTech Connect (OSTI)

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.

Christoph Beckermann; Kent Carlson

2011-07-22T23:59:59.000Z

22

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

SciTech Connect (OSTI)

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.

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

2000-10-15T23:59:59.000Z

23

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

E-Print Network [OSTI]

and shell-side condensers to increase heat transfer. This enables water chillers to reach high efficiency, it was observed that the buoyancy effect is present in the laminar region. The efficiency index (the ratio of tube is widely used in high flow rate applications because the heat transfer enhancement in high flow

Ghajar, Afshin J.

24

RELAP5/MOD3 simulation of the loss of residual heat removal during midloop operation experiment conducted at the ROSA-IV/ Large Scale Test Facility  

E-Print Network [OSTI]

The modeling of the complex thermal hydraulics Of reactor systems involves the use Of experimental test systems as well as numerical codes. A simulation of the loss of residual heat removal (RHR) during midloop operations was performed using...

Banerjee, Sibashis Sanatkumar

2012-06-07T23:59:59.000Z

25

Friction Induced Skin Tags  

E-Print Network [OSTI]

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

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

2008-01-01T23:59:59.000Z

26

Introduction Rolling and Friction  

E-Print Network [OSTI]

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

Kuhn, Matthew R.

27

Quantum friction  

E-Print Network [OSTI]

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.

R. Tsekov

2012-03-12T23:59:59.000Z

28

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

E-Print Network [OSTI]

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

Purvis, Richard

29

Roles of Dry Friction in Fluctuating Motion of Adiabatic Piston  

E-Print Network [OSTI]

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.

Tomohiko G. Sano; Hisao Hayakawa

2014-03-08T23:59:59.000Z

30

Vacuum friction in rotating particles  

E-Print Network [OSTI]

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.

A. Manjavacas; F. J. García de Abajo

2010-09-21T23:59:59.000Z

31

Skin friction blistering: computer model.  

E-Print Network [OSTI]

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

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

2007-01-01T23:59:59.000Z

32

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

E-Print Network [OSTI]

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

Plant, Robert

33

Frictional Widgets: Enhancing Touch Interfaces with Programmable Friction  

E-Print Network [OSTI]

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

Levesque, Vincent

34

Tool Wear in Friction Drilling  

SciTech Connect (OSTI)

This study investigated the wear of carbide tools used in friction drilling, a nontraditional hole-making process. In friction drilling, a rotating conical tool uses the heat generated by friction to soften and penetrate a thin workpiece and create a bushing without generating chips. The wear of a hard tungsten carbide tool used for friction drilling a low carbon steel workpiece has been investigated. Tool wear characteristics were studied by measuring its weight change, detecting changes in its shape with a coordinate measuring machine, and making observations of wear damage using scanning electron microscopy. Energy dispersive spectroscopy was applied to analyze the change in chemical composition of the tool surface due to drilling. In addition, the thrust force and torque during drilling and the hole size were measured periodically to monitor the effects of tool wear. Results indicate that the carbide tool is durable, showing minimal tool wear after drilling 11000 holes, but observations also indicate progressively severe abrasive grooving on the tool tip.

Miller, Scott F [ORNL; Blau, Peter Julian [ORNL; Shih, Albert J. [University of Michigan

2007-01-01T23:59:59.000Z

35

Rubber friction: role of the flash temperature  

E-Print Network [OSTI]

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.

B. N. J. Persson

2006-05-10T23:59:59.000Z

36

Rotational Quantum Friction  

E-Print Network [OSTI]

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.

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

2012-08-21T23:59:59.000Z

37

Nanotribology and Nanoscale Friction  

SciTech Connect (OSTI)

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.

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

38

Micromachine friction test apparatus  

DOE Patents [OSTI]

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.

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

2002-01-01T23:59:59.000Z

39

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

E-Print Network [OSTI]

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

Collins, Gary S.

40

Friction in Forming of UD Composites  

SciTech Connect (OSTI)

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.

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

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Skin friction blistering: computer model.  

E-Print Network [OSTI]

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

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

2007-01-01T23:59:59.000Z

42

Factors affecting piston ring friction  

E-Print Network [OSTI]

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 ...

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

2013-01-01T23:59:59.000Z

43

Friction Stir Processing for Efficient Manufacturing  

SciTech Connect (OSTI)

Friction at contacting surfaces in relative motion is a major source of parasitic energy loss in machine systems and manufacturing processes. Consequently, friction reduction usually translates to efficiency gain and reduction in energy consumption. Furthermore, friction at surfaces eventually leads to wear and failure of the components thereby compromising reliability and durability. In order to reduce friction and wear in tribological components, material surfaces are often hardened by a variety of methods, including conventional heat treatment, laser surface hardening, and thin-film coatings. While these surface treatments are effective when used in conjunction with lubrication to prevent failure, they are all energy intensive and could potentially add significant cost. A new concept for surface hardening of metallic materials and components is Friction Stir Processing (FSP). Compared to the current surface hardening technologies, FSP is more energy efficient has no emission or waste by products and may result in better tribological performance. FSP involves plunging a rotating tool to a predetermined depth (case layer thickness) and translating the FSP tool along the area to be processed. This action of the tool produces heating and severe plastic deformation of the processed area. For steel the temperature is high enough to cause phase transformation, ultimately forming hard martensitic phase. Indeed, FSP has been used for surface modification of several metals and alloys so as to homogenize the microstructure and refine the grain size, both of which led to improved fatigue and corrosion resistance. Based on the effect of FSP on near-surface layer material, it was expected to have beneficial effects on friction and wear performance of metallic materials. However, little or no knowledge existed on the impact of FSP concerning friction and wear performance the subject of the this project and final report. Specifically for steel, which is the most dominant tribological material, FSP can replace the current conventional surface hardening techniques used for friction and wear performance. Friction Stir Link Inc. (FSL) is teamed with Argonne National Laboratory (ANL) to develop and optimize FSP for friction and wear performance enhancement. The ultimate goal is to offer FSP and an effective alternative to some of the current energy intensive and high-cost surface hardening processes.

Mr. Christopher B. Smith; Dr. Oyelayo Ajayi

2012-01-31T23:59:59.000Z

44

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

E-Print Network [OSTI]

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...

Liu, Yao-Hsien

2006-10-30T23:59:59.000Z

45

Action of friction Frictional processes are not often considered in  

E-Print Network [OSTI]

Action of friction Frictional processes are not often considered in any detail in studies are switched off, the pressure falls to just 921mb. Frictional processes can be thought of in terms of changes. The first term on the right­hand­side represents barotropic damping by friction, and the second

Plant, Robert

46

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

E-Print Network [OSTI]

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

Simpkins, Alex

47

Friction stir welding tool  

DOE Patents [OSTI]

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.

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

2008-04-15T23:59:59.000Z

48

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

E-Print Network [OSTI]

0 Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated) viewed as a heat engine converts heat energy extracted from the ocean to kinetic energy of the TC, which is eventually dissipated due to surface friction. Since the energy production rate is a linear function while

Wang, Yuqing

49

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

E-Print Network [OSTI]

Energy Production, Frictional Dissipation, and Maximum Intensity of a Numerically Simulated as a heat engine converts heat energy extracted from the ocean into the kinetic energy of the TC, which is eventually dissipated due to surface friction. Since the energy production rate is a linear function while

Wang, Yuqing

50

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

E-Print Network [OSTI]

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

Ghajar, Afshin J.

51

Nonlinear friction in quantum mechanics  

E-Print Network [OSTI]

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.

Roumen Tsekov

2010-03-01T23:59:59.000Z

52

PEBBLES Simulation of Static Friction and New Static Friction Benchmark  

SciTech Connect (OSTI)

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.

Joshua J. Cogliati; Abderrafi M. Ougouag

2010-05-01T23:59:59.000Z

53

Friction surfaced Stellite6 coatings  

SciTech Connect (OSTI)

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.

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

54

Friction of wood on steel.  

E-Print Network [OSTI]

?? This thesis deals with the experimental description of friction between steel and wood materials, specifically laminated veneer lumber (LVL) and pine wood with two… (more)

Koubek, Radek

2014-01-01T23:59:59.000Z

55

Elastic model of dry friction  

SciTech Connect (OSTI)

Friction of elastic bodies is connected with the passing through the metastable states that arise at the contact of surfaces rubbing against each other. Three models are considered that give rise to the metastable states. Friction forces and their dependence on the pressure are calculated. In Appendix A, the contact problem of elasticity theory is solved with adhesion taken into account.

Larkin, A. I.; Khmelnitskii, D. E., E-mail: dekl2@cam.ac.uk [Landau Institute for Theoretical Physics (Russian Federation)

2013-09-15T23:59:59.000Z

56

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

E-Print Network [OSTI]

the Hydraulic Drag and Heat Transfer Coefficients in PorousT. E. W. , 1929, “Heat Transfer: A Liquid Flowing Through a5] Locke, G. L. , 1950, “Heat Transfer and Flow Friction

Geb, David; Zhou, Feng; Catton, Ivan

2012-01-01T23:59:59.000Z

57

REDUCED ENGINE FRICTION AND WEAR  

SciTech Connect (OSTI)

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.

Ron Matthews

2005-05-01T23:59:59.000Z

58

Irreversible work and inner friction in quantum thermodynamic processes  

E-Print Network [OSTI]

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.

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

2014-07-13T23:59:59.000Z

59

Implications of Strong-Rate-Weakening Friction  

E-Print Network [OSTI]

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

Greer, Julia R.

60

Modelling of friction stir welding  

E-Print Network [OSTI]

This thesis investigates the modelling of friction stir welding (FSW). FSW is a relatively new welding process where a rotating non-consumable tool is used to join two materials through high temperature deformation. The aim of the thesis...

Colegrove, Paul Andrew

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Rubber friction and tire dynamics  

E-Print Network [OSTI]

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.

B. N. J. Persson

2010-07-16T23:59:59.000Z

62

Friction Anisotropy: A unique and intrinsic property of decagonal quasicrystals  

E-Print Network [OSTI]

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

Park, Jeong Young

2008-01-01T23:59:59.000Z

63

Epistemic Friction: Reflections on Knowledge, Truth, and Logic  

E-Print Network [OSTI]

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

Sher, Gila

2010-01-01T23:59:59.000Z

64

Fusion Residues  

E-Print Network [OSTI]

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.

Kenneth Intriligator

1991-08-19T23:59:59.000Z

65

Friction between Ring Polymer Brushes  

E-Print Network [OSTI]

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.

A. Erbas; J. Paturej

2015-01-07T23:59:59.000Z

66

Microstructural issues in a friction-stir-welded aluminum alloy  

SciTech Connect (OSTI)

Recent observations of microstructures associated with friction-stir welding (FSW) in a number of aluminum alloys have consistently demonstrated the actual weld zone to consist of a (dynamically) recrystallized grain structure resulting from the extreme, solid-state, plastic deformation characterizing the process. Because of solubilities associated with the various precipitates in 7075 and 6061 aluminum alloys, and the fact that the precipitates were either homogeneously distributed throughout both the original (unwelded) work-piece plates and the well zones (or formed varying densities of Widmanstaetten patterns within the original and recrystallized grains), it has been difficult to follow the stirring of stable, second-phase particles from the base metal (work-piece) into the weld zone. In the present investigation, a compositionally modified 1100 aluminum alloy (nominally 99.2% Al, 0.5% Fe, 0.15% Cu, 0.12% Si, 0.05 Mn, 0.04 Ti, balance in weight percent of Be and Mg), forming a stable microdendritic (second-phase), equiaxed, cell structure was friction-stir welded. These thermally stable, geometrically specific, precipitates in the base metal were compared with their disposition within the friction-stir-weld zone. In addition, as-cast plates of this alloy were cold-rolled 50% and friction-stir-welded in order to compare these two schedules (as-cast and 50% cold-rolled) in terms of residual hardness variations and related microstructural issues as well as the effect of prior deformation on the friction-stir welding process.

Flores, O.V.; Kennedy, C.; Murr, L.E.; Brown, D.; Pappu, S.; Nowak, B.M.; McClure, J.C. [Univ. of Texas, El Paso, TX (United States)] [Univ. of Texas, El Paso, TX (United States)

1998-02-03T23:59:59.000Z

67

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

E-Print Network [OSTI]

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

Mishra, Bud

68

Automotive friction-induced noises A. Elmaiana  

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

69

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

70

Friction in full view A. P. Merklea  

E-Print Network [OSTI]

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

Marks, Laurence D.

71

The friction of wrinkles Hamid Mohammadi1  

E-Print Network [OSTI]

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

Mueser, Martin

72

Friction forces in cosmological models  

E-Print Network [OSTI]

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.

Donato Bini; Andrea Geralico; Daniele Gregoris; Sauro Succi

2014-08-23T23:59:59.000Z

73

Dynamical friction on satellite galaxies  

E-Print Network [OSTI]

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.

Michiko Fujii; Yoko Funato; Junichiro Makino

2005-11-22T23:59:59.000Z

74

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)

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)

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

75

Rubber friction on smooth surfaces  

E-Print Network [OSTI]

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.

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

2006-07-04T23:59:59.000Z

76

Rubber friction on (apparently) smooth lubricated surfaces  

E-Print Network [OSTI]

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.

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

2007-10-18T23:59:59.000Z

77

Friction as Basis for a Phonon Maser  

E-Print Network [OSTI]

Evidence is provided from experiment, for the hypothesis that defect organization (internal friction) is a means for operation of a phonon maser.

Randall D. Peters

2003-08-08T23:59:59.000Z

78

Residual stress patterns in steel welds  

SciTech Connect (OSTI)

Neutron strain scanning of residual stress is a valuable nondestructive tool for evaluation of residual stress in welds. The penetrating characteristic of neutrons permits mapping of strain patterns with a spatial resolution approaching 1mm at depths of 20mm in steels. While the overall patterns of the residual stress tensor in a weld are understood, the detailed patterns depend on welding process parameters and the effects of solid state transformation. The residual strain profiles in two multi-pass austenitic welds and a ferritic steel weld are presented. The stress-free lattice parameters within the fusion zone and the adjacent heat affected zone in the two austenitic welds show that the interpretation of residual stress from strains are affected by welding parameters. An interpretation of the residual strain pattern in the ferritic steel plate can be made using the strain measurements of a Gleeble test bar which has undergone the solid state austenite decomposition.

Spooner, S.; Hubbard, C.R.; Wang, X.L.; David, S.A.; Holden, T.M. [Oak Ridge National Lab., TN (United States); Root, J.H.; Swainson, I. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada)

1994-12-31T23:59:59.000Z

79

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

E-Print Network [OSTI]

Abstract--Friction modeling is essential for joint dynamic identification and control. Joint friction is composed of a viscous and a dry friction force. According to Coulomb law, dry friction depends linearly on the load in the transmission. However, in robotics field, a constant dry friction is frequently

Paris-Sud XI, Université de

80

Some Hamiltonian Models of Friction  

E-Print Network [OSTI]

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.

Juerg Froehlich; Zhou Gang; Avy Soffer

2010-11-04T23:59:59.000Z

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Non-equilibrium Statistical Approach to Friction Models  

E-Print Network [OSTI]

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.

Shoichi Ichinose

2014-04-26T23:59:59.000Z

82

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

E-Print Network [OSTI]

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,

McLaskey, Gregory Christofer

2011-01-01T23:59:59.000Z

83

EVALUATION OF A LOW FRICTION - HIGH EFFICIENCY ROLLER BEARING ENGINE  

SciTech Connect (OSTI)

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.

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

2009-06-30T23:59:59.000Z

84

Evaluation of microstructure and mechanical properties in friction stir processed SKD61 tool steel  

SciTech Connect (OSTI)

A SKD61 tool steel was friction stir processed using a polycrystalline cubic boron nitride tool. Microstructure, tensile properties and wear characteristic were evaluated. Fine grains with a martensite structure were produced in the friction stir processed zone, which led to the increase of the microindentation hardness. The grains became finer when the heat input was lowered. The transverse tensile strength of the friction stir processed zone was equal to that of base metal and all the tensile specimens fractured at base metal zone. The wear width and depth of the friction stir processed zone at the load of 1.96 N were 339 {mu}m and 6 {mu}m, as compared to 888 {mu}m and 42 {mu}m of the base metal, decreased by 62% and 86%. Findings of the present study suggest that low heat input is an effective method to produce a friction stir processed zone composed of relatively fine grain martensitic structure with good tensile properties and wear characteristic.

Chen, Y.C., E-mail: armstrong@hit.edu.cn [Joining and Welding Research Institute, Osaka University, Osaka 567-0047 (Japan); Nakata, K. [Joining and Welding Research Institute, Osaka University, Osaka 567-0047 (Japan)

2009-12-15T23:59:59.000Z

85

Dissimilar friction welding of titanium alloys to alloy 718  

SciTech Connect (OSTI)

The design of advanced, high-performance gas-turbine engines will require the utilization of elevated-temperature titanium-based materials, including conventional alloys, titanium aluminides, and titanium metal-matrix composites. The most efficient utilization of these materials in the engine compressor section would be achieved by directly joining these materials to existing nickel-base superalloys, such as Alloy 718. To date, the dissimilar welding of titanium alloys to nickel-based alloys has not been common practice because intermetallic compounds form in the weld and cause embrittlement. Special welding techniques must be developed to inhibit this compound formation and to provide high strength welds. In this investigation, a friction welding process was developed for joining titanium alloys (Ti-6Al-2Sn-4Zr-2Mo and Ti-6Al-4V) to nickel-based superalloy Alloy 718. An interlayer system comprised of copper and niobium sheet layers was employed as a diffusion barrier and weld deformation enhancer. A postweld heat treatment (PWHT, 700{degrees}C for 20 min in vacuum) under axial pressure (Ksi) was used to improve the joint strength consistency. The following conclusions can be drawn from this investigation: (1) A friction welding technique has been developed for joining titanium alloys (Ti-6Al-2Sn-4Zr-2Mo and Ti-6Al-4V) to Alloy 718 using an interlayer system of niobium and copper. Joint strengths averaging approximately 50 Ksi were achieved. (2) Deformation was concentrated in the interlayers, especially the copper interlayer, during friction welding. Increased reduction in length (RIL) during friction welding resulted in a decrease in the interlayer thicknesses. (3) The EDS results showed that the niobium and copper interlayers prevent interdiffusion between the two parent metals, producing formation of detrimental phases.

Kuo, M.; Albright, C.E.; Baeslack, W.A. III

1994-12-31T23:59:59.000Z

86

Friction Coefficient for Quarks in Supergravity Duals  

E-Print Network [OSTI]

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.

E. Antonyan

2006-11-22T23:59:59.000Z

87

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

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

Friction of Steel Sliding Under Boundary Lubrication Regime in Commercial Gear Oils at Elevated Temperatures Friction of Steel Sliding Under Boundary Lubrication Regime in...

88

Efficiency Improvement through Reduction in Friction and Wear...  

Broader source: Energy.gov (indexed) [DOE]

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

89

Friction forces on phase transition fronts  

SciTech Connect (OSTI)

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.

Mégevand, Ariel, E-mail: megevand@mdp.edu.ar [IFIMAR (CONICET–UNMdP), Departamento de Física, Facultad de Ciencias Exactas y Naturales, UNMdP, Deán Funes 3350, (7600) Mar del Plata (Argentina)

2013-07-01T23:59:59.000Z

90

Dynamical Friction on extended perturbers  

E-Print Network [OSTI]

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.

O. Esquivel; B. Fuchs

2008-04-01T23:59:59.000Z

91

Skin friction for steel piles in sand  

E-Print Network [OSTI]

SkiN FRICTION FOR STEZL PIIZS IN SAND A Theeia by I. H. Sulaiman Submittei io the graduate College of t, he Texan AAB Univen-ity in Ixantial fulfil. ment of bhe zequiremenbu for the degree of NASTZR 0F SCISNCZ May 196'7 bsrjor Subject...: Civil Engineering SKIN FRICTION FOR STEEL PILES IN SAND A Thesis by I. H. Sulaiman Approved as to style and content by: Chairman of C mmittee Head of Department Memb Member 111 Skin Friction For Steel Piles in Sand (May 1967) Ibr shim Hikmat...

Sulaiman, Ibrahim Hikmat

2012-06-07T23:59:59.000Z

92

Friction Problems in Servomechanisms: Modeling and Compensation Techniques  

E-Print Network [OSTI]

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

Gravdahl, Jan Tommy

93

Postulated Mesoscale Quantum of Internal Friction Hysteresis  

E-Print Network [OSTI]

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.

Randall D. Peters

2004-05-27T23:59:59.000Z

94

Compton-Energy Scale of Friction Quantization  

E-Print Network [OSTI]

Numerous different experiments by the author, approaching nearly two decades of study, point strongly toward the possibility that friction operates around a mesoscale quantum of energy having the value 11 pJ.

Randall D. Peters

2006-07-03T23:59:59.000Z

95

Friction of Materials for Automotive Applications  

SciTech Connect (OSTI)

This brief overview of friction-related issues in materials for automobiles is invited for a special issue on automotive materials in the ASM journal AM&P. It describes a range of areas in a ground vehicle in which friction must be controlled or minimized. Applications range from piston rings to tires, and from brakes to fuel injector components. A perspective on new materials and lubricants, and the need for validation testing is presented.

Blau, Peter Julian [ORNL

2013-01-01T23:59:59.000Z

96

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

E-Print Network [OSTI]

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...

Jacobs, Clifford Albert

1967-01-01T23:59:59.000Z

97

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

E-Print Network [OSTI]

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.

Yves Pomeau; David C. Roberts

2007-04-17T23:59:59.000Z

98

Status of Stellite 6 friction testing  

SciTech Connect (OSTI)

For the past several years, researchers at the Idaho National Engineering and Environmental Laboratory, under the sponsorship of the US Nuclear Regulatory Commission, Office of Nuclear Regulatory Research, have been investigating the performance of motor-operated valves subjected to design basis flow and pressure loads. Part of this research addresses the friction that occurs at the interface between the valve disc and the valve body seats during operation of a gate valve. In most gate valves, these surfaces are hardfaced with Stellite 6, a cobalt-based alloy. Analytical methods exist for predicting the thrust needed to operate these valves at specific pressure conditions. To produce accurate valve thrust predictions, the analyst must have a reasonably accurate, though conservative, estimate of the coefficient of friction at the disc-to-seat interface. One of the questions that remains to be answered is whether, and to what extent, aging of the disc and seat surfaces effects the disc-to-seat coefficient of friction. Specifically, does the environment in a nuclear plants piping system cause the accumulation of an oxide film on these surfaces that increases the coefficient of friction; and if so, how great is the increase? This paper presents results of specimen tests addressing this issue, with emphasis on the following: (1) the characteristics and thickness of the oxide film that develops on Stellite 6 as it ages; (2) the change in the friction coefficient of Stellite 6 as it ages, including the question of whether the friction coefficient eventually reaches a plateau; and (3) the effect in-service cycling has on the characteristics and thickness of the oxide film and on the friction coefficient.

Watkins, J.C.; DeWall, K.G. [Lockheed Martin Idaho Technologies Co., Idaho Falls, ID (United States). Idaho National Engineering and Environmental Lab.; Weidenhamer, G.H. [Nuclear Regulatory Commission (United States)

1998-06-01T23:59:59.000Z

99

Casimir Friction Force Between Polarizable Media  

E-Print Network [OSTI]

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.

Johan S. Hřye; Iver Brevik

2012-01-18T23:59:59.000Z

100

Enhancement of disoriented chiral condensate domains with friction  

E-Print Network [OSTI]

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.

A. K. Chaudhuri

1999-04-08T23:59:59.000Z

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Method and device for frictional welding  

DOE Patents [OSTI]

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.

Peacock, H.B.

1991-01-01T23:59:59.000Z

102

Method and device for frictional welding  

DOE Patents [OSTI]

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.

Peacock, H.B.

1992-10-13T23:59:59.000Z

103

Method and device for frictional welding  

DOE Patents [OSTI]

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.

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

1992-01-01T23:59:59.000Z

104

Macroscopic approach to the Casimir friction force  

E-Print Network [OSTI]

The general formula is derived for the vacuum friction force between two parallel perfectly flat planes bounding two material media separated by a vacuum gap and moving relative to each other with a constant velocity $\\mathbf{v}$. The material media are described in the framework of macroscopic electrodynamics whereas the nonzero temperature and dissipation are taken into account by making use of the Kubo formulae from non-equilibrium statistical thermodynamics. The formula obtained provides a rigorous basis for calculation of the vacuum friction force within the quantum field theory methods in the condensed matter physics. The revealed $v$-dependence of the vacuum friction force proves to be the following: for zero temperature ($T=0$) it is proportional to $(v/c)^3$ and for $T>0$ this force is linear in $(v/c)$.

V. V. Nesterenko; A. V. Nesterenko

2014-03-13T23:59:59.000Z

105

Casimir friction at zero and finite temperatures  

E-Print Network [OSTI]

The Casimir friction problem for dielectric plates that move parallel to each other is treated by assuming one of the plates to be at rest. The other performs a closed loop motion in the longitudinal direction. Therewith by use of energy dissipation the formalism becomes more manageable and transparent than in the conventional setting where uniform sliding motion is assumed from $t=-\\infty$ to $t=+\\infty$. One avoids separating off a reversible interparticle force (independent of friction) from the total force. Moreover, the cases of temperatures $T=0$ and finite $T$ are treated on the same footing. For metal plates we find the friction force to be proportional to $v^3$ at $T=0$ while at finite $T$ it is proportional to $v$ for small $v$ as found earlier. Comparisons with earlier results of Pendry (1997, 2010) and Barton (2011) are made.

Johan S. Hřye; Iver Brevik

2014-03-26T23:59:59.000Z

106

Friction and dilatancy in immersed granular matter  

E-Print Network [OSTI]

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.

Thibaut Divoux; Jean-Christophe Géminard

2008-06-10T23:59:59.000Z

107

Dynamical friction in modified Newtonian dynamics  

E-Print Network [OSTI]

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.

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

2008-03-31T23:59:59.000Z

108

Negative skin friction at Keehi interchange  

E-Print Network [OSTI]

is assumed to be the sum of the structural load, gt, a drag force, F'n, due to the fill within the pile group and a drag force F'n due to the negative skin friction of the soft layer. F = ()t + F'n + F"n (2. 1) where F'n is the weight of fill carried... of this method for an actual case. 2. 2. 3 Brome Brome (1969) describes the state of the practice in Sweden for the calculation of drag forces on piles due to negative skin friction. In Sweden most piles are driven to rock. The compression of the pile...

Porwoll, Hubert

2012-06-07T23:59:59.000Z

109

High fidelity frictional models for MEMS.  

SciTech Connect (OSTI)

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.

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

110

Composite heat damage assessment  

SciTech Connect (OSTI)

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.

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

111

IMPROVING MIX DESIGN AND CONSTRUCTION OF PERMEABLE FRICTION COURSE MIXTURES  

E-Print Network [OSTI]

Permeable friction course (PFC), or new generation open-graded friction course (OGFC) mixtures, are hot mix asphalt (HMA) characterized by high total air voids (AV) content (minimum 18 %) as compared to the most commonly used dense-graded HMA...

Alvarez Lugo, Allex Eduardo

2012-02-14T23:59:59.000Z

112

Friction Stir Welding John Hinch and John Rudge  

E-Print Network [OSTI]

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

Rudge, John

113

Enhancing Physicality in Touch Interaction with Programmable Friction  

E-Print Network [OSTI]

Enhancing Physicality in Touch Interaction with Programmable Friction Vincent LĂ©vesque1 , 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

Levesque, Vincent

114

Friction versus dilation revisited: Insights from theoretical and numerical models  

E-Print Network [OSTI]

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

Einat, Aharonov

115

ORIGINAL PAPER Modeling of Thermal-Assisted Dislocation Friction  

E-Print Network [OSTI]

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

Marks, Laurence D.

116

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

E-Print Network [OSTI]

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 the variation of the friction force as a function of time. We study nominally flat surfaces of matching aluminum

Buldyrev, Sergey

117

Friction-Induced Vibrations in Railway Transportation Chandra Prakash Sharma  

E-Print Network [OSTI]

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

Phani, A. Srikantha

118

Friction and Adhesion Hysteresis between Surfactant Monolayers in Water  

E-Print Network [OSTI]

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

Klein, Jacob

119

Analysis and Model-Based Control of Servomechanisms With Friction  

E-Print Network [OSTI]

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

Papadopoulos, Evangelos

120

Solid friction in gel electrophoresis S. F. Burlatskya)  

E-Print Network [OSTI]

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

Deutch, John

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Molecular friction and epitactic coupling between monolayers in supported bilayers  

E-Print Network [OSTI]

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

Boyer, Edmond

122

Friction as an activated process Ondej Soucek, Frantisek Gallovic  

E-Print Network [OSTI]

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

Cerveny, Vlastislav

123

ON THE IDENTIFICATION AND HAPTIC DISPLAY OF FRICTION  

E-Print Network [OSTI]

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

Stanford University

124

Seismic Interstory Drift Demands in Steel Friction Damped Braced Buildings  

E-Print Network [OSTI]

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...

Peternell Altamira, Luis E.

2010-01-16T23:59:59.000Z

125

Critical length limiting super-low friction  

E-Print Network [OSTI]

Since the demonstration of super-low friction (superlubricity) in graphite at nanoscale, one of the main challenges in the field of nano- and micro-mechanics was to scale this phenomenon up. A key question to be addressed is to what extent superlubricity could persist, and what mechanisms could lead to its failure. Here, using an edge-driven Frenkel-Kontorova model, we establish a connection between the critical length above which superlubricity disappears and both intrinsic material properties and experimental parameters. A striking boost in dissipated energy with chain length emerges abruptly due to a high-friction stick-slip mechanism caused by deformation of the slider leading to a local commensuration with the substrate lattice. We derived a parameter-free analytical model for the critical length that is in excellent agreement with our numerical simulations. Our results provide a new perspective on friction and nano-manipulation and can serve as a theoretical basis for designing nano-devices with super-low friction, such as carbon nanotubes.

Ming Ma; Andrea Benassi; Andrea Vanossi; Michael Urbakh

2015-01-02T23:59:59.000Z

126

Casimir Friction Force for Moving Harmonic Oscillators  

E-Print Network [OSTI]

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.

Johan S. Hřye; Iver Brevik

2011-11-21T23:59:59.000Z

127

Heat pipe array heat exchanger  

DOE Patents [OSTI]

A heat pipe arrangement for exchanging heat between two different temperature fluids. The heat pipe arrangement is in a ounterflow relationship to increase the efficiency of the coupling of the heat from a heat source to a heat sink.

Reimann, Robert C. (Lafayette, NY)

1987-08-25T23:59:59.000Z

128

Shear Jamming in Granular Experiments without Basal Friction  

E-Print Network [OSTI]

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.

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

2014-04-29T23:59:59.000Z

129

Friction Tests in Magnesium Tube Hydroforming at Elevated Temperatures  

SciTech Connect (OSTI)

In metal forming, lubricants have a variety of functions. The top priority is usually reduction of friction in order to increase the formability of the materials and reduce tool wear. Because magnesium alloys have very poor formability at room temperature, it is essential to manufacture a part from Magnesium alloys at elevated temperatures. The aim of this paper is to present a friction test method to evaluate the performance of different kinds of lubricants and determine their coefficients of friction at elevated temperatures in tube hydroforming of magnesium alloys. A self-designed experimental apparatus is used to carry out the experiments of friction tests. The coefficient of friction between the tube and die at guiding zone is determined. The effects of the internal pressure, the axial feeding velocity and temperatures on the friction forces and coefficients of friction for different lubricants are discussed.

Hwang, Yeong-Maw; Wang, Kuo-Hsing; Kuo, Tsung-Yu [National Sun Yat-Sen University-Department of Mechanical and Electro-mechanical Engineering, No.70, Lien-Hai Rd., Kaohsiung, Taiwan (China)

2011-05-04T23:59:59.000Z

130

Friction Reduction for Microhole CT Drilling  

SciTech Connect (OSTI)

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.

Ken Newman; Patrick Kelleher; Edward Smalley

2007-03-31T23:59:59.000Z

131

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

E-Print Network [OSTI]

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 ...

Rohsenow, Warren M.

1951-01-01T23:59:59.000Z

132

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

E-Print Network [OSTI]

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.

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

2006-06-26T23:59:59.000Z

133

Control of friction at the nanoscale  

DOE Patents [OSTI]

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.

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

2010-04-06T23:59:59.000Z

134

The effect of friction on drum brakes  

SciTech Connect (OSTI)

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.

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

1995-12-31T23:59:59.000Z

135

Friction- and wear-reducing coating  

DOE Patents [OSTI]

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.

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

2011-10-18T23:59:59.000Z

136

Mutual Friction in Superfluid Neutron Stars  

E-Print Network [OSTI]

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.

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

2005-10-03T23:59:59.000Z

137

Some Hamiltonian models of friction II  

SciTech Connect (OSTI)

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 Froehlich et al. ['Some hamiltonian models of friction,' J. Math. Phys. 52(8), 083508 (2011)], describing a tracer particle in a dispersive medium is investigated, and decay properties of the solution are proven. This work is an extension of Froehlich et al. ['Friction in a model of hamiltonian dynamics,' Commun. Math. Phys. 315(2), 401-444 (2012)]; 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.

Egli, Daniel; Gang Zhou [Institute for Theoretical Physics, ETH Zurich, CH-8093 Zuerich (Switzerland)

2012-10-15T23:59:59.000Z

138

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

SciTech Connect (OSTI)

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)

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

139

Dynamic recrystallization in friction surfaced austenitic stainless steel coatings  

SciTech Connect (OSTI)

Friction surfacing involves complex thermo-mechanical phenomena. In this study, the nature of dynamic recrystallization in friction surfaced austenitic stainless steel AISI 316L coatings was investigated using electron backscattered diffraction and transmission electron microscopy. The results show that the alloy 316L undergoes discontinuous dynamic recrystallization under conditions of moderate Zener-Hollomon parameter during friction surfacing. - Highlights: Black-Right-Pointing-Pointer Dynamic recrystallization in alloy 316L friction surfaced coatings is examined. Black-Right-Pointing-Pointer Friction surfacing leads to discontinuous dynamic recrystallization in alloy 316L. Black-Right-Pointing-Pointer Strain rates in friction surfacing exceed 400 s{sup -1}. Black-Right-Pointing-Pointer Estimated grain size matches well with experimental observations in 316L coatings.

Puli, Ramesh, E-mail: rameshpuli2000@gmail.com; Janaki Ram, G.D.

2012-12-15T23:59:59.000Z

140

Friction (Chapter 5, section 8) & Circular Motion (Chapter 6,  

E-Print Network [OSTI]

1 Week 5 Friction (Chapter 5, section 8) & Circular Motion (Chapter 6, sections 1-2) Lecture Quiz 1 travels in time t is: A. x B. 1.5x C. 3x D. 4.5x E. 9x Forces of Friction When an object to the interactions between the object and its environment This resistance is called the force of friction Forces

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

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

E-Print Network [OSTI]

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

Thomas, Amanda

2012-01-01T23:59:59.000Z

142

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

E-Print Network [OSTI]

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

Nicolas, Chamot-Rooke

143

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...

144

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

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

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 Evaluation...

145

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...

146

Micro- and macroscale coefficients of friction of cementitious materials  

SciTech Connect (OSTI)

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.

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

147

Friction of different monolayer lubricants in MEMs interfaces.  

SciTech Connect (OSTI)

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.

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

148

The influence of internal friction on rotordynamic instability  

E-Print Network [OSTI]

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....

Srinivasan, Anand

2004-09-30T23:59:59.000Z

149

Engine Friction Reduction Through Surface Finish and Coatings...  

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

and Coatings Opportunities exist for friction reduction in piston rings and valve trains using durable, advanced material technologies, such as diamond-like carbon (DLC)...

150

Friction in a Model of Hamiltonian Dynamics  

E-Print Network [OSTI]

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.

Juerg Froehlich; Zhou Gang; Avy Soffer

2011-10-29T23:59:59.000Z

151

Casimir friction: Relative motion more generally  

E-Print Network [OSTI]

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.

Johan S. Hřye; Iver Brevik

2014-09-23T23:59:59.000Z

152

A Drucker-Prager model for elastic contact with friction; A Drucker-Prager model for elastic contact with friction.  

E-Print Network [OSTI]

?? In mumerical contact simulations with friction, the simple Coloumb law is usually employed. Standard plasticity models are difficult to use since the balance enforced… (more)

wu, yunxian

2011-01-01T23:59:59.000Z

153

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]

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

Cambridge, University of

154

Initial Development in Joining of ODS Alloys Using Friction Stir Welding  

SciTech Connect (OSTI)

Solid-state welding of oxide-dispersion-strengthened (ODS) alloy MA956 sheets using friction stir welding (FSW) was investigated. Butt weld was successfully produced. The weld and base metals were characterized using optical microscopy, scanning electronic microscopy, transmission electronic microscopy, and energy dispersion x-ray spectrum. Microhardness mapping was also conducted over the weld region. Analyses indicate that the distribution of the strengthening oxides was preserved in the weld. Decrease in microhardness of the weld was observed but was insignificant. The preliminary results seem to confirm the envisioned feasibility of FSW application to ODS alloy joining. For application to Gen IV nuclear reactor heat exchanger, further investigation is suggested.

Ren, Weiju [ORNL; Feng, Zhili [ORNL

2007-08-01T23:59:59.000Z

155

Neutron scattering residual stress measurements on gray cast iron brake discs  

SciTech Connect (OSTI)

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.

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

1996-11-01T23:59:59.000Z

156

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

E-Print Network [OSTI]

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

Riddle, R.A.

2010-01-01T23:59:59.000Z

157

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...

158

Weak formulations and solution multiplicity of equilibrium configurations with Coulomb friction  

E-Print Network [OSTI]

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

Bostan, Mihai

159

SRC Residual fuel oils  

DOE Patents [OSTI]

Coal solids (SRC) and distillate oils are combined to afford single-phase blends of residual oils which have utility as fuel oils substitutes. The components are combined on the basis of their respective polarities, that is, on the basis of their heteroatom content, to assure complete solubilization of SRC. The resulting composition is a fuel oil blend which retains its stability and homogeneity over the long term.

Tewari, Krishna C. (Whitehall, PA); Foster, Edward P. (Macungie, PA)

1985-01-01T23:59:59.000Z

160

Solar heat collector  

SciTech Connect (OSTI)

An evacuated double-tubing solar heat collector is described comprising: an inner tube having an open end and a closed end; a selective absorption film applied over an exterior surface of the inner tube; an outer tube having an open end and a closed end; the inner tube being constructed to be received within the outer tube; and a substantially continuous annular coil spring ring being substantially found in cross section and of a predetermined thickness. The coil spring ring is disposed between and engages an interior surface of the outer tube and the exterior surface of the inner tube for spacing and resiliently supporting the inner tube relative to the outer tube. The ring is freely rotatably positioned to be moved axially along the length of the inner tube due only to frictional forces exerted on the coil spring. The coil spring ring is positioned on the inner tube at approximately a middle position along the length of the inner tube by being initially positioned on the inner tube adjacent to the closed end thereof and rotated upon itself axially along the inner tube only by frictional engagement with the interior surface of the outer tube as the inner tube is inserted into the open end of the outer tube and moved to a fully inserted position within the outer tube. The open end of the inner tube and the open end of the outer tube are fused to form a junction and hermetically sealed.

Takeuchi, H.; Mikiya, T.

1987-03-17T23:59:59.000Z

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Friction and the Inverted Pendulum Stabilization Problem Sue Ann Campbell  

E-Print Network [OSTI]

Friction and the Inverted Pendulum Stabilization Problem Sue Ann Campbell Department of Applied. Keywords: inverted pendulum, friction, feedback control, stability analysis. 1 #12;INTRODUCTION to be the cause of failure of a feedback controller to stabilize a three link inverted pendulum system [2

Campbell, Sue Ann

162

Friction Stir Welding of Lightweight Vehicle Structures: Final Report  

SciTech Connect (OSTI)

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.

Sanella, M.L.

2008-08-31T23:59:59.000Z

163

Role of Friction in Materials Selection for Automotive Applications  

SciTech Connect (OSTI)

This is an invited article for a special issue of the ASM International monthly magazine that concerns "Automotive Materials and Applications." The article itself overviews frictional considerations in material selection for automobiles. It discusses implications for energy efficiency (engine friction) and safety (brakes) among other topics.

Blau, Peter Julian [ORNL

2013-01-01T23:59:59.000Z

164

Quantized friction force: Lindbladian model satisfying Ehrenfest theorems  

E-Print Network [OSTI]

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.

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

2014-12-05T23:59:59.000Z

165

METHODS PAPER Addressing Practical Challenges of Low Friction Coefficient  

E-Print Network [OSTI]

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

Sawyer, Wallace

166

The nonlinear nature of friction Michael Urbakh1  

E-Print Network [OSTI]

) 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

La Rosa, Andres H.

167

Friction coefficient of soft contact lenses: measurements and modeling  

E-Print Network [OSTI]

, 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

Sawyer, Wallace

168

Model coupling friction and adhesion for steel-concrete interfaces  

E-Print Network [OSTI]

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

Boyer, Edmond

169

Certification of a weld produced by friction stir welding  

DOE Patents [OSTI]

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.

Obaditch, Chris; Grant, Glenn J

2013-10-01T23:59:59.000Z

170

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

E-Print Network [OSTI]

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...

Subramanian, Karthik

2006-04-12T23:59:59.000Z

171

E-Print Network 3.0 - asbestos-free friction lining Sample Search...  

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

identification necessary. Off-line identification of friction is described by Armstrong 2... -feedback PD part and of an on-line friction compensation term, T f , which...

172

E-Print Network 3.0 - avoid friction induced Sample Search Results  

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

friction induced Search Powered by Explorit Topic List Advanced Search Sample search results for: avoid friction induced Page: << < 1 2 3 4 5 > >> 1 INITIAL DEVELOPMENT OF A...

173

Ice friction: The effects of surface roughness, structure, and hydrophobicity  

SciTech Connect (OSTI)

The effect of surface roughness, structure, and hydrophobicity on ice friction is studied systematically over a wide range of temperature and sliding speeds using several metallic interfaces. Hydrophobicity in combination with controlled roughness at the nanoscale is achieved by femtosecond laser irradiation to mimic the lotus effect on the slider's surface. The controlled roughness significantly increases the coefficient of friction at low sliding speeds and temperatures well below the ice melting point. However, at temperatures close to the melting point and relatively higher speeds, roughness and hydrophobicity significantly decrease ice friction. This decrease in friction is mainly due to the suppression of capillary bridges in spite of the presence of surface asperities that facilitate their formation. Finally, grooves oriented in the sliding direction also significantly decrease friction in the low velocity range compared to scratches and grooves randomly distributed over a surface.

Kietzig, Anne-Marie; Hatzikiriakos, Savvas G.; Englezos, Peter [Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, British Columbia V6T 1Z3 (Canada)

2009-07-15T23:59:59.000Z

174

Nonlocal microscopic theory of quantum friction between parallel metallic slabs  

SciTech Connect (OSTI)

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.

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

175

Aspect ratio effect on heat transfer in rotating two-pass rectangular channels with smooth walls and ribbed walls  

E-Print Network [OSTI]

buoyancy parameter, (?? /? )xRo2(Rx/Dh) Dh hydraulic diameter de diameter of coolant exit hole e rib height f friction factor fo fully developed friction factor in non-rotating smooth tube h heat transfer coefficient H channel height k...) . N. K. Anand (Member) . D. L. O?Neal (Head of Department) May 2005 Major Subject: Mechanical Engineering iii ABSTRACT Aspect Ratio Effect on Heat Transfer in Rotating Two...

Fu, Wen-Lung

2005-08-29T23:59:59.000Z

176

Frictional granular mechanics: A variational approach  

SciTech Connect (OSTI)

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.

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

2009-10-16T23:59:59.000Z

177

Dynamical friction force exerted on spherical bodies  

E-Print Network [OSTI]

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.

O. Esquivel; B. Fuchs

2007-04-30T23:59:59.000Z

178

Some Hamiltonian Models of Friction II  

E-Print Network [OSTI]

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.

Daniel Egli; Gang Zhou

2011-08-29T23:59:59.000Z

179

High temperature low friction surface coating  

DOE Patents [OSTI]

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.

Bhushan, Bharat (Watervliet, NY)

1980-01-01T23:59:59.000Z

180

Evaluation of residual stress gradients in ductile cast iron using critical refracted longitudinal (Lcr) wave technique  

E-Print Network [OSTI]

improper or unnecessary heat-treatments extremely costly. Knowledge of the residual stress ipudient can make production of the component much more efficient and economicaL This knowledge could also be used to predict service life of components...

Pfluger, Ron Atlan

1995-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Adaptive controller for regenerative and friction braking system  

DOE Patents [OSTI]

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.

Davis, R.I.

1990-10-16T23:59:59.000Z

182

Power-law friction in closely-packed granular materials  

E-Print Network [OSTI]

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.

Takahiro Hatano

2007-05-08T23:59:59.000Z

183

Adaptive controller for regenerative and friction braking system  

DOE Patents [OSTI]

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.

Davis, Roy I. (Ypsilanti, MI)

1990-01-01T23:59:59.000Z

184

Effect of friction on disoriented chiral condensate formation  

E-Print Network [OSTI]

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.

A. K. Chaudhuri

1998-09-08T23:59:59.000Z

185

The ground state problem for a quantum Hamiltonian model describing friction  

E-Print Network [OSTI]

The ground state problem for a quantum Hamiltonian model describing friction Laurent Bruneau friction introduced in [4]. This model consists of a particle which interacts with a bosonic reservoir is violated in the case of linear friction, but satis#28;ed when the friction force is proportional

186

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

E-Print Network [OSTI]

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

De Luca, Alessandro

187

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

E-Print Network [OSTI]

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

Al Hanbali, Ahmad

188

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

E-Print Network [OSTI]

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

Attard, Phil

189

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

190

Demonstrations: blocks on planes, scales, to find coefficients of static and kinetic friction  

E-Print Network [OSTI]

Demonstrations: ·blocks on planes, scales, to find coefficients of static and kinetic friction Text: Fishbane 5-1, 5-2 Problems: 18, 21, 28, 30, 34 from Ch. 5 What's important: ·frictional forces ·coefficients of static and kinetic friction Friction Where objects move in contact with other objects, we know

Boal, David

191

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

E-Print Network [OSTI]

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

Zollman, Dean

192

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

E-Print Network [OSTI]

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

Mueser, Martin

193

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 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

Bartuccelli, Michele

194

GENERALIZED NEWTON METHODS FOR THE 2DSIGNORINI CONTACT PROBLEM WITH FRICTION  

E-Print Network [OSTI]

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

Kunisch, Karl

195

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,...

196

Friction Modeling and Compensation for an Industrial Robot  

E-Print Network [OSTI]

Friction Modeling and Compensation for an Industrial Robot Stephen M. Phillips and Kevin R. Ballou it is assumed to be unpredictable or insignificant. In experiments on the PUMA 560 robot arm, Armstrong' dem

197

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...

198

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...

199

On the friction coefficient of straight-chain aggregates  

E-Print Network [OSTI]

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.

Lorenzo Isella; Yannis Drossinos

2010-07-16T23:59:59.000Z

200

Friction anisotropy: A unique and intrinsic property of decagonal quasicrystals  

SciTech Connect (OSTI)

We show that friction anisotropy is an intrinsic property of the atomic structure of Al-Ni-Co decagonal quasicrystals and not only of clean and well-ordered surfaces that can be prepared in vacuum [J.Y. Park et al., Science309, 1354 (2005)]. Friction anisotropy is manifested in both nanometer-size contacts obtained with sharp atomic force microscope tips and macroscopic contacts produced in pin-on-disk tribometers. We show that the friction anisotropy, which is not observed when an amorphous oxide film covers the surface, is recovered when the film is removed due to wear. Equally important is the loss of the friction anisotropy when the quasicrystalline order is destroyed due to cumulative wear. These results reveal the intimate connection between the mechanical properties of these materials and their peculiar atomic structure.

Park, J. Y.; Ogletree, D.; Salmeron, M.

2008-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Rolling friction for hard cylinder and sphere on viscoelastic solid  

E-Print Network [OSTI]

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.

B. N. J. Persson

2010-08-26T23:59:59.000Z

202

Frictional properties of faults: from observation on the  

E-Print Network [OSTI]

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

Winfree, Erik

203

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...

204

A laboratory study of the friction behavior of granular materials  

E-Print Network [OSTI]

I report on laboratory experiments designed to investigate the microphysical processes that result in rate- and state-dependent friction behavior and experiments designed to match the boundary conditions used by numerical ...

Frye, Kevin M. (Kevin Michael), 1972-

2002-01-01T23:59:59.000Z

205

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

E-Print Network [OSTI]

. 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...

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

2006-01-01T23:59:59.000Z

206

Formation mechanism of linear friction welded Ti-6Al-4V alloy joint based on microstructure observation  

SciTech Connect (OSTI)

The microstructure of the linear friction welded Ti-6Al-4V titanium alloy joint was investigated by optical microscope, scanning electronic microscope and transmission electron microscope. Results show that the dynamic recovery and recrystallization resulting from the intensive plastic deformation and fast heating and cooling processes during linear friction welding account for the superfine {alpha} + {beta} grains in the weld center. Fine {alpha} grains distribute in the {beta} matrix or at the boundaries of {beta} grains. A mass of dislocations networks and metastructures present within the {alpha} and {beta} grains. - Research Highlights: {yields} TEM is employed in the analysis. {yields} The dynamic recovery is the main mechanism in thermal deformation of TC4. {yields} Superfine grains in the weld result from dynamic recovery and dynamic recrystallizaion, but the recrystallization is inadequate.

Ma Tiejun; Chen Tao, E-mail: ctwc-13@163.com; Li Wenya; Wang Shiwei; Yang Siqian

2011-01-15T23:59:59.000Z

207

Small mass asymptotic for the motion with vanishing friction  

E-Print Network [OSTI]

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.

Mark Freidlin; Wenqing Hu; Alexander Wentzell

2012-01-05T23:59:59.000Z

208

The role of crystallography and nanostructures on metallic friction.  

SciTech Connect (OSTI)

In ductile metals, sliding contact is often accompanied by severe plastic deformation localized to a small volume of material adjacent to the wear surface. During the initial run-in period, hardness, grain structure and crystallographic texture of the surfaces that come into sliding contact undergo significant changes, culminating in the evolution of subsurface layers with their own characteristic features. Here, a brief overview of our ongoing research on the fundamental phenomena governing the friction-induced recrystallization in single crystal metals, and how these recrystallized structures with nanometer-size grains would in turn influence metallic friction will be presented. We have employed a novel combination of experimental tools (FIB, EBSD and TEM) and an analysis of the critical resolved shear stress (RSS) on the twelve slip systems of the FCC lattice to understand the evolution of these friction-induced structures in single crystal nickel. The later part of the talk deals with the mechanisms of friction in nanocrystalline Ni films. Analyses of friction-induced subsurfaces seem to confirm that the formation of stable ultrafine nanocrystalline layers with 2-10 nm grains changes the deformation mechanism from the traditional dislocation mediated one to that is predominantly controlled by grain boundaries, resulting in significant reductions in the coefficient friction.

Michael, Joseph Richard; Prasad, Somuri V.; Battaile, Corbett Chandler; Majumdar, Bhaskar Sinha (New Mexico Institute of Mining & Technology, Socorro, NM); Kotula, Paul Gabriel

2010-06-01T23:59:59.000Z

209

Bar-Halo Friction in Galaxies II: Metastability  

E-Print Network [OSTI]

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.

J. A. Sellwood; Victor P. Debattista

2005-11-05T23:59:59.000Z

210

Yield criteria for quasibrittle and frictional materials  

E-Print Network [OSTI]

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.

Davide Bigoni; Andrea Piccolroaz

2010-10-09T23:59:59.000Z

211

Elastic Properties and Internal Friction of Two Magnesium Alloys at Elevated Temperatures  

SciTech Connect (OSTI)

The elastic properties and internal friction of two magnesium alloys were studied from 25 C to 450 C using Resonant Ultrasound Spectroscopy (RUS). The Young's moduli decrease with increasing temperature. At 200 C, a change in the temperature dependence of the elastic constants is observed. The internal friction increases significantly with increasing temperature above 200 C. The observed changes in the temperature dependence of the elastic constants and the internal friction are the result of anelastic relaxation by grain boundary sliding at elevated temperatures. Elastic properties govern the behavior of a materials subjected to stress over a region of strain where the material behaves elastically. The elastic properties, including the Young's modulus (E), shear modulus (G), bulk modulus (B), and Poisson's ratio (?), are of significant interest to many design and engineering applications. The choice of the most appropriate material for a particular application at elevated temperatures therefore requires knowledge of its elastic properties as a function of temperature. In addition, mechanical vibration can cause significant damage in the automotive, aerospace, and architectural industries and thus, the ability of a material to dissipate elastic strain energy in materials, known as damping or internal friction, is also important property. Internal friction can be the result of a wide range of physical mechanisms, and depends on the material, temperature, and frequency of the loading. When utilized effectively in engineering applications, the damping capacity of a material can remove undesirable noise and vibration as heat to the surroundings. The elastic properties of materials can be determined by static or dynamic methods. Resonant Ultrasound Spectroscopy (RUS), used in this study, is a unique and sophisticated non-destructive dynamic technique for determining the complete elastic tensor of a solid by measuring the resonant spectrum of mechanical resonance for a sample of known geometry, dimensions, and mass. In addition, RUS allows determination of internal friction, or damping, at different frequencies and temperatures. Polycrystalline pure magnesium (Mg) exhibits excellent high damping properties. However, the poor mechanical properties limit the applications of pure Mg. Although alloying can improve the mechanical properties of Mg, the damping properties are reduced with additions of alloying elements. Therefore, it becomes necessary to study and develop Mg-alloys with simultaneous high damping capacity and improved mechanical properties. Moreover, studies involving the high temperature dynamic elastic properties of Mg alloys are limited. In this study, the elastic properties and internal friction of two magnesium alloys were studied at elevated temperatures using RUS. The effect of alloy composition and grain size was investigated. The wrought magnesium alloys AZ31 and ZK60 were employed. Table 1 gives the nominal chemical compositions of these two alloys. The ZK60 alloy is a commercial extruded plate with a T5 temper, i.e. solution-treated at 535 C for two hours, quenched in hot water, and aged at 185 C for 24 hours. The AZ31 alloy is a commercial rolled plate with a H24 temper, i.e. strain hardened and partially annealed.

Freels, M.; Liaw, P. K.; Garlea, E.; Morrell, J. S.; Radiovic, M.

2011-06-01T23:59:59.000Z

212

MECHANICAL PROPERTIES AND MICROSTRUCTURAL CHARACTERIZATION OF A MULTILAYERED MULTIPASS FRICTION STIR WELD IN STEEL  

SciTech Connect (OSTI)

Multilayered multipass friction stir welding (MM-FSW) makes it possible to use FSW to fabricate thick-section structures. In this work, MM-FSW was demonstrated on a high strength low alloy steel; ASTM A572 Grade 50. Three steel plates with thicknesses of 0.18", 0.18", 0.24" respectively were stacked and friction stir welded together to form a 0.6" thick welded structure. The welded plate was sectioned into rectangular bars transverse to the weld direction for tensile testing to evaluate mechanical properties. Digital image correlation (DIC) was employed to map the local strain fields during tensile testing. The initial failure was found to occur simultaneously at the bottom and middle layers away from the weld zone. The top layer failed last in the base metal. The failure locations were consistent among different samples tested. Also, Charpy V-notch impact tests were conducted for weld metal, heat affected zone, and the base metal at each layer as a function of temperature. The weld microstructures were characterized using optical and electron microscopy and micro-hardness mapping.

Lim, Yong Chae [ORNL; Sanderson, Samuel [MegaStir Technologies LLC; Mahoney, Murray [Consultant; Qiao, Dongxiao [ORNL; Wang, Yanli [ORNL; Zhang, Wei [ORNL; Feng, Zhili [ORNL

2013-01-01T23:59:59.000Z

213

Mechanical and metallurgical properties of MMC friction welds  

SciTech Connect (OSTI)

The mechanical and metallurgical properties of similar and dissimilar welds involving aluminum-based metal matrix composite (MMC) base material were investigated using factorial experimentation. The test materials comprised aluminum-based alloy 6061/Al{sub 2}O{sub 3} (W6A.10A-T6), aluminum Alloy 6061-T6 and AISI 304 stainless steel. Notch tensile strength increased when high friction pressures were employed during MMC/MMC, MMC/Alloy 6061, MMC/AISI 304 stainless steel and Alloy 6061/Alloy 6061 friction welding. In MMC/Alloy 6061 welds, notch tensile strength also increased when high forging pressures were employed. Applied oxide films on both the MMC and AISI stainless steel substrates had a markedly detrimental effect on dissimilar weld mechanical properties. The optimum notch tensile strength properties were produced when high friction pressure values were applied during dissimilar MMC/AISI 304 stainless steel welding. High friction pressure had two beneficial effects, i.e., it decreased the thickness of the FeAl{sub 3} intermetallic film and it promoted disruption and dispersal of oxide films at the joint interface. In direct contrast, the presence of thick anodized oxide films on the MMC substrate surface prior to friction welding had no observable influence on MMC/MMC weld mechanical properties.

Li, Z.; Maldonado, C.; North, T.H. [Univ. of Toronto, Ontario (Canada). Dept. of Metallurgy and Materials Science; Altshuller, B. [Alcan R and D Labs., Kingston, Ontario (Canada)

1997-09-01T23:59:59.000Z

214

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...

215

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...

216

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...

217

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...

218

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...

219

Couette flow regimes with heat transfer in rarefied gas  

SciTech Connect (OSTI)

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.

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

220

The Schroedinger equation with friction from the quantum trajectory perspective  

SciTech Connect (OSTI)

Similarity of equations of motion for the classical and quantum trajectories is used to introduce a friction term dependent on the wavefunction phase into the time-dependent Schroedinger equation. The term describes irreversible energy loss by the quantum system. The force of friction is proportional to the velocity of a quantum trajectory. The resulting Schroedinger equation is nonlinear, conserves wavefunction normalization, and evolves an arbitrary wavefunction into the ground state of the system (of appropriate symmetry if applicable). Decrease in energy is proportional to the average kinetic energy of the quantum trajectory ensemble. Dynamics in the high friction regime is suitable for simple models of reactions proceeding with energy transfer from the system to the environment. Examples of dynamics are given for single and symmetric and asymmetric double well potentials.

Garashchuk, Sophya; Dixit, Vaibhav; Gu Bing; Mazzuca, James [Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208 (United States)

2013-02-07T23:59:59.000Z

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Friction and Wear Behavior of Ultrahigh Molecular Weight Polyethylene as a Function of Crystallinity in the Presence of the  

E-Print Network [OSTI]

Friction and Wear Behavior of Ultrahigh Molecular Weight Polyethylene as a Function: In this study, the friction and wear behavior of ultrahigh molecular weight polyethylene (UHMWPE) were evaluated Words: ultrahigh molecular weight polyethylene (UHMWPE), crystallinity, friction, wear, phospholipid

Lin, Zhiqun

222

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...

223

Heating system  

SciTech Connect (OSTI)

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.

Nishman, P.J.

1983-03-08T23:59:59.000Z

224

DISSOLUTION OF NEPTUNIUM OXIDE RESIDUES  

SciTech Connect (OSTI)

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.

Kyser, E

2009-01-12T23:59:59.000Z

225

Flexible Hybrid Friction Stir Joining Technology  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeat PumpRecordFederal7.pdfFlash_2010_-24.pdf Flash_2010_-24.pdf2009 DOEthe

226

Impurity gas effects on friction and wear of high-temperature materials for VHTRs  

SciTech Connect (OSTI)

Concentration being varied up to about10/sup 3/ PPM. developed at the Japan Atomic Energy Research Institute, reactor components, such as heat transfer tubes (Hastelloy-XR) of an intermediate heat exchanger, hot duct liners (Hastelloy-XR), core support plates (2 1/4 Cr-1 Mo steel), control rod sheaths (HastelloyXR), orifice devices (SUS 304), fuel blocks (graphite), and others, are exposed to helium gas coolant with a temperature of 1000/sup 0/C and a pressure of 4.1 MPa. The relative sliding movements of the structure, which are stimulated by flow-induced vibration, constraint force, and thermal expansion, might cause unfavorable friction and wear. Sliding wear tests were carried out on PGX graphite, 2 1/4 Cr-1 Mo steel, and heat- and corrosion-resistant Hastelloy-XR in 500 to 1000/sup 0/C. Environmental helium gas pressures of 0.2 and 4.1 MPa were chosen to compare the influence of the pressures. The effects of four different impurity gases (O/sub 2/, H/sub 2/, H/sub 2/O, and CH/sub 4/) on tribological behavior were studied, each gas Concentration being aried up to about10/sup 3/ PPM.

Kikuchi, K.; Kawaguchi, K.; Nemoto, M.; Sanokawa, K.; Watanabe, S.

1984-09-01T23:59:59.000Z

227

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

E-Print Network [OSTI]

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

Suresh, Subra

228

Piston ring design for reduced friction in modern internal combustion engines  

E-Print Network [OSTI]

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 ...

Smedley, Grant, 1978-

2004-01-01T23:59:59.000Z

229

Usage of Friction-damped Braced Frames for Seismic Vibration Control  

E-Print Network [OSTI]

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...

Fink, Brynnan 1992-

2012-04-16T23:59:59.000Z

230

Experimental Characterization of the Effect of Charring on the Residual Load Carrying Capacity of a Structural Fibre Reinforced Composite   

E-Print Network [OSTI]

An experimental study conducted to investigate the residual load carrying capacity of a commonly used structural composite plastic, isophthalic polyester, reinforced with S-glass fibreglass when exposed to heat-fluxes ...

Hill, David J; Torero, Jose L

2004-01-01T23:59:59.000Z

231

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

E-Print Network [OSTI]

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

Grujicic, Mica

232

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

E-Print Network [OSTI]

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

Vu-Quoc, Loc

233

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

234

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

E-Print Network [OSTI]

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

Boyer, Edmond

235

M.-T. DO, P. MARSAC, Y. DELANNE Prediction of Tire/Wet Road Friction from  

E-Print Network [OSTI]

M.-T. DO, P. MARSAC, Y. DELANNE 1 Prediction of Tire/Wet Road Friction from Road Surface, validation of a contact model for the prediction of low-speed friction from road surface microtexture the friction ­ speed curve from road- and tire measurable parameters. The model development is briefly

Paris-Sud XI, Université de

236

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

E-Print Network [OSTI]

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

Mueser, Martin

237

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

E-Print Network [OSTI]

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

Tsiotras, Panagiotis

238

Collective friction coefficients in the relaxation time approximation F. A. Ivanyuk  

E-Print Network [OSTI]

Collective friction coefficients in the relaxation time approximation F. A. Ivanyuk Institute components of the friction coefficient for various single-particle potentials and have found that the nondiagonal component of the friction coefficient depends generally on the diffuseness of the potential

Pomorski, Krzysztof

239

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

E-Print Network [OSTI]

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

Natelson, Douglas

240

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

E-Print Network [OSTI]

1 Long Term Friction: from Stick-Slip to Stable Sliding1 Christophe Voisin1 , François Renard1 Abstract. We have devised an original laboratory experiment where we investigate6 the frictional behaviour, salt, an analogue for natural8 faults, allows for frictional processes plastic deformation and pressure

Paris-Sud XI, Université de

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

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

242

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

E-Print Network [OSTI]

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

Rossi, Riccarda

243

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

E-Print Network [OSTI]

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

Boyer, Edmond

244

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

245

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

246

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

E-Print Network [OSTI]

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

Rossi, Riccarda

247

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

E-Print Network [OSTI]

1 Long Term Friction: from Stick-Slip to Stable Sliding Christophe Voisin1 , François Renard1 where we investigate the frictional behaviour of a single crystal salt slider over a large number for friction and plastic deformation and pressure solution creep to be efficient on the same timescale. During

Paris-Sud XI, Université de

248

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

E-Print Network [OSTI]

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

Roder, Heinrich

249

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

E-Print Network [OSTI]

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

Goldstein, Seth Copen

250

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

E-Print Network [OSTI]

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

Morris, Kirsten

251

Journal of Sound and Vibration (1997) 202(2), 203218 SEMI-ACTIVE CONTROL OF FRICTION  

E-Print Network [OSTI]

Journal of Sound and Vibration (1997) 202(2), 203­218 SEMI-ACTIVE CONTROL OF FRICTION DAMPERS P, U.S.A. (Received 22 January 1996, and in final form 21 October 1996) Semi-active control of friction dampers has been proposed to improve the energy dissipation characteristics of passive friction dampers

Dupont, Pierre

252

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

E-Print Network [OSTI]

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

Tsiotras, Panagiotis

253

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

E-Print Network [OSTI]

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

Ge, Shuzhi Sam

254

Nonlinear friction of a damped dimer sliding on a periodic substrate S. Gonalves,1,2,  

E-Print Network [OSTI]

Nonlinear friction of a damped dimer sliding on a periodic substrate S. Gonçalves,1,2, * V. M, USA (Received 23 July 2004; published 12 November 2004) The nonlinear sliding friction of a dimer over that the friction force has an approximate v-3 depen- dence if the velocity is sufficiently large

Kenkre, V.M.

255

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

E-Print Network [OSTI]

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

Hollerbach, John M.

256

ACC03-ASME0018 Controller Design for Flexible Systems with Friction  

E-Print Network [OSTI]

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

Singh, Tarunraj

257

Friction, Frontogenesis, and the Stratification of the Surface Mixed Layer LEIF THOMAS*  

E-Print Network [OSTI]

Friction, Frontogenesis, and the Stratification of the Surface Mixed Layer LEIF THOMAS* Department restratification resulting from frontogenesis in regions of confluent flow. Frictional forces acting of friction versus frontogenesis in the restratification of the mixed layer and are tested using numerical

Thompson, Andrew

258

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

E-Print Network [OSTI]

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

Hagen, Stephen J.

259

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

260

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

E-Print Network [OSTI]

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

Kudrolli, Arshad

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

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

E-Print Network [OSTI]

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

Grujicic, Mica

262

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

E-Print Network [OSTI]

Acta Materialia 59 (2011) 2020-2028 1 Back of the envelope calculations in friction stir welding: friction stir welding; modeling; theory; velocity field; peak temperature; torque; hardness; aluminum in friction stir welding (FSW) [1-53] have been tested against experimental data for the joining of aluminum

Cambridge, University of

2011-01-01T23:59:59.000Z

263

Statistical Analysis of High-Cycle Fatigue Behavior of Friction Stir Welded AA5083-H321  

E-Print Network [OSTI]

Statistical Analysis of High-Cycle Fatigue Behavior of Friction Stir Welded AA5083-H321 M. Grujicic AA5083, fatigue behavior, friction stir welding, maximum likelihood estimation 1. Introduction Friction stir welding (FSW) is a relatively new solid-state metal-joining process that was invented

Grujicic, Mica

264

Friction Stir Weld Failure Mechanisms in Aluminum-Armor Structures Under Ballistic  

E-Print Network [OSTI]

Friction Stir Weld Failure Mechanisms in Aluminum-Armor Structures Under Ballistic Impact Loading and of the attendant ballistic-impact failure mechanisms in prototypical friction stir welding (FSW) joints found limit, failure mechanisms, friction stir welding 1. Introduction In the context of military tactical

Grujicic, Mica

265

Review: friction stir welding tools , H. K. D. H. Bhadeshia3  

E-Print Network [OSTI]

Review: friction stir welding tools R. Rai1 , A. De2 , H. K. D. H. Bhadeshia3 and T. DebRoy*1 Friction stir welding (FSW) is a widely used solid state joining process for soft materials ability, mechanisms of tool degradation and process economics. Keywords: Friction stir welding, Tool

Cambridge, University of

266

Coupling Boltzmann and Navier-Stokes equations by friction  

SciTech Connect (OSTI)

The aim of this paper is to introduce and validate a coupled Navier-Stokes Boltzman approach for the calculation of hypersonic rarefied flows around maneuvering vehicles. The proposed strategy uses locally a kinetic model in the boundary layer coupled through wall friction forces to a global Navier-Stokes solver. Different numerical experiments illustrate the potentialities of the method. 29 refs., 24 figs.

Bourgat, J.F. [INRIA, Le Chesnay (France)] [INRIA, Le Chesnay (France); Le Tallec, P. [Universite Paris, Dauphine (France)] [Universite Paris, Dauphine (France); [INRIA, Le Chesnay (France); Tidriri, M.D. [ICASE, Hampton, VA (United States)] [ICASE, Hampton, VA (United States)

1996-09-01T23:59:59.000Z

267

Brownian ratchet in a thermal bath driven by Coulomb friction  

E-Print Network [OSTI]

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.

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

2013-01-14T23:59:59.000Z

268

Wetting and friction on superoleophobic surfaces March 20, 2009  

E-Print Network [OSTI]

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

Paris-Sud XI, Université de

269

Nanomanipulation Experiments Exploring Frictional and Mechanical Properties of Carbon Nanotubes  

E-Print Network [OSTI]

Nanomanipulation Experiments Exploring Frictional and Mechanical Properties of Carbon Nanotubes M that places the human operator directly into the feedback loop that controls surface manipulations. Using. The mechanical properties of carbon nanotubes have been demonstrated to be extraordinary. They have an elastic

Falvo, Michael

270

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

E-Print Network [OSTI]

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

Klein, Jacob

271

Lateral position detection and control for friction stir systems  

DOE Patents [OSTI]

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.

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

272

TBM tunnel friction values for the Grizzly Powerhouse Project  

SciTech Connect (OSTI)

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.

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

273

Casimir Friction Force and Energy Dissipation for Moving Harmonic Oscillators  

E-Print Network [OSTI]

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.

Johan S. Hřye; Iver Brevik

2010-01-14T23:59:59.000Z

274

Smoluchowski-Kramers approximation in the case of variable friction  

E-Print Network [OSTI]

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.

Mark Freidlin; Wenqing Hu

2012-03-03T23:59:59.000Z

275

TEMPORARILY ALLOYING TITANIUM TO FACILITATE FRICTION STIR WELDING  

SciTech Connect (OSTI)

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.

Hovanski, Yuri

2009-05-06T23:59:59.000Z

276

Modeling of friction-induced deformation and microstructures.  

SciTech Connect (OSTI)

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.

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

277

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

SciTech Connect (OSTI)

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.

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

278

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

E-Print Network [OSTI]

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.

Mahendra K. Verma

2012-03-23T23:59:59.000Z

279

Heat collector  

DOE Patents [OSTI]

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.

Merrigan, Michael A. (Santa Cruz, NM)

1984-01-01T23:59:59.000Z

280

Heat collector  

DOE Patents [OSTI]

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.

Merrigan, M.A.

1981-06-29T23:59:59.000Z

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Finite quantum dissipation: the challenge of obtaining specific heat  

E-Print Network [OSTI]

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.

Hänggi, Peter; Talkner, Peter

2008-01-01T23:59:59.000Z

282

Corrosive resistant heat exchanger  

DOE Patents [OSTI]

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.

Richlen, Scott L. (Annandale, VA)

1989-01-01T23:59:59.000Z

283

Experimental determination of residual stress by neutron diffraction in a boiling water reactor core shroud  

SciTech Connect (OSTI)

Residual strains in a 51 mm (2-inch) thick 304L stainless steel plate have been measured by neutron diffraction and interpreted in terms of residual stress. The plate, measuring (300 mm) in area, was removed from a 6m (20-ft.) diameter unirradiated boiling water reactor core shroud, and included a multiple-pass horizontal weld which joined two of the cylindrical shells which comprise the core shroud. Residual stress mapping was undertaken in the heat affected zone, concentrating on the outside half of the plate thickness. Variations in residual stresses with location appeared consistent with trends expected from finite element calculations, considering that a large fraction of the residual hoop stress was released upon removal of the plate from the core shroud cylinder.

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

1996-06-01T23:59:59.000Z

284

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

E-Print Network [OSTI]

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

Loss, Daniel

285

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

SciTech Connect (OSTI)

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.

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

286

Effect of fluorocarbon self-assembled monolayer films on sidewall adhesion and friction of surface micromachines with impacting and sliding contact interfaces  

SciTech Connect (OSTI)

A self-assembled monolayer film consisting of fluoro-octyltrichlorosilane (FOTS) was vapor-phase deposited on Si(100) substrates and polycrystalline silicon (polysilicon) surface micromachines. The hydrophobic behavior and structural composition of the FOTS film deposited on Si(100) were investigated by goniometry and X-ray photoelectron spectroscopy, respectively. The effects of contact pressure, relative humidity, temperature, and impact/sliding cycles on the adhesive and friction behavior of uncoated and FOTS-coated polysilicon micromachines (referred to as the Si and FOTS/Si micromachines, respectively) were investigated under controlled loading and environmental conditions. FOTS/Si micromachines demonstrated much lower and stable adhesion than Si micromachines due to the highly hydrophobic and conformal FOTS film. Contrary to Si micromachines, sidewall adhesion of FOTS/Si micromachines demonstrated a weak dependence on relative humidity, temperature, and impact cycles. In addition, FOTS/Si micromachines showed low and stable adhesion and low static friction for significantly more sliding cycles than Si micromachines. The adhesive and static friction characteristics of Si and FOTS/Si micromachines are interpreted in the context of physicochemical surface changes, resulting in the increase of the real area of contact and a hydrophobic-to-hydrophilic transition of the surface chemical characteristics caused by nanoscale surface smoothening and the removal of the organic residue (Si micromachines) or the FOTS film (FOTS/Si micromachines) during repetitive impact and oscillatory sliding of the sidewall surfaces.

Xiang, H.; Komvopoulos, K. [Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States)] [Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States)

2013-06-14T23:59:59.000Z

287

Micro-beam friction liner and method of transferring energy  

DOE Patents [OSTI]

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.

Mentesana, Charles (Leawood, KS)

2007-07-17T23:59:59.000Z

288

Simple LMFBR axial-flow friction-factor correlation  

SciTech Connect (OSTI)

Complicated LMFBR axial lead-length averaged friction-factor correlations are reduced to an easy, ready-to-use function of bundle Reynolds number for wire-wrapped bundles. The function together with the power curves to calculate the associated constants are incorporated in a computer preprocessor, EZFRIC. The constants required for the calculation of the subchannels and bundle friction factors are derived and correlated into power curves of geometrical parameters. A computer program, FRIC, which can alternatively be used to accurately calculate these constants is also included. The accurate values of the constants and the corresponding values predicted by the power curves and percentage error of prediction are tabulated for a wide variety of geometries of interest.

Chan, Y.N.; Todreas, N.E.

1982-12-01T23:59:59.000Z

289

Rack-and-pinion effects in molecular rolling friction  

E-Print Network [OSTI]

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.

Oleg M. Braun; Erio Tosatti

2008-09-05T23:59:59.000Z

290

Friction and the oscillatory motion of granular flows  

E-Print Network [OSTI]

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.

Lydie Staron

2012-11-26T23:59:59.000Z

291

Friction Properties of Molybdenum Alloyed Steel at Elevated Temperatures  

SciTech Connect (OSTI)

The high-temperature properties of steel surface can be improved by molybdenum surface alloying. Molybdenzing was carried out on carbon steel in the multi-function double glow plasma surface alloying furnace. The friction and wear tests were conducted on a high temperature ball-on-disk tribometer under the temperature of 25 deg. C{approx}600 deg. C. The contents of alloy element varied with alloyed layer were detected by SEM attached with EDS. The molybdenized layer is composed of the deposited layer and diffused layer. The micro-hardness of alloyed layer decreases from HV650 on the top layer to HV240. The friction coefficient of molybdenized layer decreases from 0.5{approx}0.6 to 0.2{approx}0.3 and wear rate decreases by 20% at elevated temperature after molybdenizing.

Li Jianliang; Xiong Dangsheng [Department of Material Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094 (China); Wu Hongyan [College of Math and Physics, Nanjing University of Information and Technology, Nanjing, 210044 (China)

2011-01-17T23:59:59.000Z

292

Friction vs Texture at the Approach of a Granular Avalanche  

E-Print Network [OSTI]

We perform a novel analysis of the granular texture of a granular bed close to stability limit. Our analysis is based on a unique criterion of friction mobilisation in a simulated two-dimensional packing. In this way, we recover the bimodal character of granular texture, and the coexistence of weak and strong phases in the sense of distinct contacts populations. Moreover, we show the existence of a well-defined subset of contacts within the weak contact network. These contacts are characterized by their important friction, and form a highly coherent population in terms of fabric. They play an antagonistic role with respect to force chains. We are thus able to discriminate between incoherent contacts and coherent contacts in the weak phase, and to specify the role that the latter plays in the destabilisation process.

Lydie Staron; Farhang Radjai

2005-05-04T23:59:59.000Z

293

Liquid friction on charged surfaces: from hydrodynamic slippage to electrokinetics  

E-Print Network [OSTI]

Hydrodynamic behavior at the vicinity of a confining wall is closely related to the friction properties of the liquid/solid interface. Here we consider, using Molecular Dynamics simulations, the electric contribution to friction for charged surfaces, and the induced modification of the hydrodynamic boundary condition at the confining boundary. The consequences of liquid slippage for electrokinetic phenomena, through the coupling between hydrodynamics and electrostatics within the electric double layer, are explored. Strong amplification of electro-osmotic effects is revealed, and the non-trivial effect of surface charge is discussed. This work allows to reconsider existing experimental data, concerning Zeta potentials of hydrophobic surfaces and suggest the possibility to generate ``giant'' electro-osmotic and electrophoretic effects, with direct applications in microfluidics.

Laurent Joly; Christophe Ybert; Emmanuel Trizac; Lyderic Bocquet

2006-07-19T23:59:59.000Z

294

In-situ measurement of skin friction and point bearing  

E-Print Network [OSTI]

'-7. 80' Device Limiting Values (psf) 8 ft Pile Limiting Values (psf) 205 952 Unconfined Shear Strength (psf) 1095 1915 '/26 l 4I'26 l Srmur? taneous I-2-1 I-2-2 I-2-3 I-2-4 2 I gll 2'-8" 5 '-'4" 5 I 4II Tip = 1880 Friction.... 02 5. 26 2. 34 3. 74 3. 71 . 233 . 396 . 337 . 364 . 318 TABLE VI FRICTION DARING DATA Height of P P 'dy st P /P (lbs) (lbs) dy st Pile Displacement Velocity J' (fps) (sec/ft) , 0. 35 O I 21 811 2'-8" C I I II J -4 5'-4" 51...

Rehmet, Joseph Don

1970-01-01T23:59:59.000Z

295

A novel system to study wear, friction, and lubricants  

SciTech Connect (OSTI)

A novel enclosed (pressurized) multispecimen wear testing system was design and built to allow the fully computerized on-line measurement and control of friction, wear, and lubricants of different materials (metals, ceramics, composites, and plastics). This system is described in detail. The tribological parameters can be adjusted and controlled to reproduce the actual conditions that prevail in machine components. Several examples of the capabilities of the system are presented.

Maamouri, M.; Masson, J.F.; Marchand, N.J. (Ecole Polytechnique, Montreal, Quebec (Canada). Dept. de Metallurgie et de Genie des Materiaux)

1994-08-01T23:59:59.000Z

296

Friction Control Solutions Inc FriCSo | Open Energy Information  

Open Energy Info (EERE)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data CenterFranconia, Virginia: Energy Resources Jump to: navigation, search Equivalent URI DBpediaFredonia,Iowa BioProcessAreaFresnoFriction

297

Flow and Heat-Transfer Apparatus, Instrumentation and Data Acquisition Method  

E-Print Network [OSTI]

friction and convective heat transfer characteristics of nanofluids. Instead of a usual closed-loop system where pumps and after-cooling units are required, the developed apparatus utilizes nitrogen pressure-driven flow to test a single batch of fluid. This reduces the complexity of the system while improving its

Kostic, Milivoje M.

298

1 Copyright 2012 by ASME Proceedings of the ASME 2012 Summer Heat Transfer Conference  

E-Print Network [OSTI]

and pressure drop is of significant importance in artificial gas lift systems. The understanding of two phase lift systems and pipelines carrying oil and natural gas mixture over long distances. The frictional pressure drop is desired in the designing of the direct expansion ground source heat pumps systems

Ghajar, Afshin J.

299

Solid Friction from stick-slip to pinning and aging  

E-Print Network [OSTI]

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.

Tristan Baumberger; Christiane Caroli

2005-06-24T23:59:59.000Z

300

Hydrodynamics of rapidly rotating superfluid neutron stars with mutual friction  

E-Print Network [OSTI]

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.

A. Passamonti; N. Andersson

2010-04-26T23:59:59.000Z

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Reducing Skin Friction and Heat Transfer over a Hypersonic Cruising Vehicle by Mass Injection.  

E-Print Network [OSTI]

??Demonstrating technologies for hypersonic aircraft that cruise at speeds greater than Mach 5 is one of the long-term visions of many agencies, like NASA. Reducing… (more)

Nozaki, Yoshifumi

2007-01-01T23:59:59.000Z

302

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

E-Print Network [OSTI]

in which two opposite walls are roughened with parallel and crossed arrays of full ribs, cross-cut discrete ribs, and beveled discrete ribs. The discrete ribs are staggered in alternate rows of three and two ribs The rib-roughened channel models..., 000 and 80, 000. Results are also obtained for parallel arrays of cross-cut discrete ribs with a = 45 and ? 45' on alternate rows. Both parallel angled cross-cut and beveled discrete ribs are superior to 90" discrete ribs and corresponding parallel...

McMillin, Robert Dale

1989-01-01T23:59:59.000Z

303

Heating System Specification Specification of Heating System  

E-Print Network [OSTI]

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

Day, Nancy

304

Transforms for prediction residuals in video coding  

E-Print Network [OSTI]

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 ...

Kam??l?, Fatih

2010-01-01T23:59:59.000Z

305

Residual stress measurement on ductile cast iron using critically refracted longitudinal (Lcr) wave technique  

E-Print Network [OSTI]

of requirements for the degree of MASTER OF SCIENCE December 1991 Major Subject: Mechanical Engineering RESIDUAL STRESS MEASUREMENT IN DUCTILE CAST IRON USING CRITICALLY REFRACTED LONGITUDINAL (Lcm) WAVE TECHNIQUE A Thesis by SRINIVASULU NAIDU CHUNDU.... In an attempt to study the effect of heat-treatment on the acoustoelastic behavior of ductile cast iron, four continuously cast ductile iron bars were investigated. While one bar was retained as-cast, the other three bars were subjected to heat...

Chundu, Srinivasulu Naidu

1991-01-01T23:59:59.000Z

306

Feasibility of natural circulation heat transport in the ENHS.  

SciTech Connect (OSTI)

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.

Sienicki, J.J.

2002-02-14T23:59:59.000Z

307

Feasibility of Natural Circulation Heat Transport in the ENHS  

SciTech Connect (OSTI)

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)

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

2002-07-01T23:59:59.000Z

308

Microcomputer analysis of regenerative heat exchangers for oscillating flow  

SciTech Connect (OSTI)

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.

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

1987-03-01T23:59:59.000Z

309

Heat transfer in the trailing edge cooling channels of turbine blades  

E-Print Network [OSTI]

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...

Kumaran, T. K.

1989-01-01T23:59:59.000Z

310

Impact of Low-Friction Surface Treatments on Engine Friction | Department  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensionalthe U.S. Department-2023 Idaho4 AUDITofDepartmentof Energy

311

Efficiency Improvement through Reduction in Friction and Wear in Powertrain Systems  

SciTech Connect (OSTI)

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

Michael Killian

2009-09-30T23:59:59.000Z

312

Effects of Stone-Wales and vacancy defects in atomic-scale friction on defective graphite  

SciTech Connect (OSTI)

Graphite is an excellent solid lubricant for surface coating, but its performance is significantly weakened by the vacancy or Stone-Wales (SW) defect. This study uses molecular dynamics simulations to explore the frictional behavior of a diamond tip sliding over a graphite which contains a single defect or stacked defects. Our results suggest that the friction on defective graphite shows a strong dependence on defect location and type. The 5-7-7-5 structure of SW defect results in an effectively negative slope of friction. For defective graphite containing a defect in the surface, adding a single vacancy in the interior layer will decrease the friction coefficients, while setting a SW defect in the interior layer may increase the friction coefficients. Our obtained results may provide useful information for understanding the atomic-scale friction properties of defective graphite.

Sun, Xiao-Yu [Department of Engineering Mechanics, School of Civil Engineering, Wuhan University, Wuhan 430072 (China); Key Laboratory of Hubei Province for Water Jet Theory and New Technology, Wuhan University, Wuhan 430072 (China); Wu, RunNi; Xia, Re [Key Laboratory of Hubei Province for Water Jet Theory and New Technology, Wuhan University, Wuhan 430072 (China); Chu, Xi-Hua; Xu, Yuan-Jie, E-mail: yj-xu@whu.edu.cn [Department of Engineering Mechanics, School of Civil Engineering, Wuhan University, Wuhan 430072 (China)

2014-05-05T23:59:59.000Z

313

Residual stresses in bakelite models induced by quenching  

E-Print Network [OSTI]

and the bellows was extended to six inobes. Lifter proper focusing and using a Kodachrome type 4 film, separate piotures were made at openings f8, fll, f16, and f22 in order to provide for a suitable spread of exposure. Sodium vapor was used as the source... for determining the residual stresses or the elastic redistribution of stresses that occurs after the prototype has undergone some plastio deformation or heat treatment. The creep characteristics of bakelite, BT-61-893, become appreciable with temperatures...

Jarvi, Ray Victor

1952-01-01T23:59:59.000Z

314

Process to recycle shredder residue  

DOE Patents [OSTI]

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.

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

2001-01-01T23:59:59.000Z

315

Interplay of friction and noise and enhancement of disoriented chiral condensate  

E-Print Network [OSTI]

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.

A. K. Chaudhuri

2000-11-01T23:59:59.000Z

316

E-Print Network 3.0 - alloy friction stir Sample Search Results  

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

and Young... conditions. Most works on internal friction have been done on dilute solid solution alloys. Some works have... . This is a multi-element alloy prepared by...

317

E-Print Network 3.0 - adhesive microstructure friction Sample...  

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

at Berkeley Collection: Physics 20 How to get the yield locus of an adhesive powder from a single numerical experiment Summary: with experiments. The effect of friction...

318

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

SciTech Connect (OSTI)

This program aims at improving the efficiency of advanced natural-gas reciprocating engines (ANGRE) by reducing piston/ring assembly friction without major adverse effects on engine performance, such as increased oil consumption and emissions. A detailed set of piston/ring dynamic and friction models have been developed and applied that illustrated the fundamental relationships between design parameters and friction losses. Various low-friction strategies and concepts have been explored, and engine experiments will validate these concepts. An iterative process of experimentation, simulation and analysis, will be followed with the goal of demonstrating a complete optimized low-friction engine system. As planned, MIT has developed guidelines for an initial set of low-friction piston-ring-pack designs. Current recommendations focus on subtle top-piston-ring and oil-control-ring characteristics. A full-scale Waukesha F18 engine has been installed at Colorado State University and testing of the baseline configuration is in progress. Components for the first design iteration are being procured. Subsequent work includes examining the friction and engine performance data and extending the analyses to other areas to evaluate opportunities for further friction improvement and the impact on oil consumption/emission and wear, towards demonstrating an optimized reduced-friction engine system.

Victor W. Wong; Tian Tian; Grant Smedley

2003-08-28T23:59:59.000Z

319

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

E-Print Network [OSTI]

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...

Oakes, Timothy Andrew

1991-01-01T23:59:59.000Z

320

Geothermal heating  

SciTech Connect (OSTI)

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.

Aureille, M.

1982-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Friction stir welding tool and process for welding dissimilar materials  

DOE Patents [OSTI]

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.

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

2013-05-07T23:59:59.000Z

322

Curvature effect on tearing modes in presence of neoclassical friction  

SciTech Connect (OSTI)

Neoclassical physics (here associated to the poloidal variation of the magnetic field strength along field lines in a tokamak) is well known for driving self-generated plasma current and nonlinear magnetic islands associated to it in high performance, ITER relevant plasma discharges. It is demonstrated that the neoclassical friction between a magnetic perturbation and plasma flow already impacts magnetic islands in the linear regime, by inducing a weakening of curvature stabilization for tearing modes. This conclusion holds in particular for regimes where convection is influencing the pressure dynamics, as shown using a simple analytical model and confirmed in full Magneto-Hydro-Dynamics simulations.

Maget, Patrick; Mellet, Nicolas; Meshcheriakov, Dmytro; Garbet, Xavier [CEA, IRFM, F-13108 Saint Paul-lez-Durance (France)] [CEA, IRFM, F-13108 Saint Paul-lez-Durance (France); Lütjens, Hinrich [Centre de Physique Théorique, Ecole Polytechnique, CNRS (France)] [Centre de Physique Théorique, Ecole Polytechnique, CNRS (France)

2013-11-15T23:59:59.000Z

323

Fluctuations in a kinetic transport model for quantum friction  

E-Print Network [OSTI]

We consider a linear Boltzmann equation that arises in a model for quantum friction. It describes a particle that is slowed down by the emission of bosons. We study the stochastic process generated by this Boltzmann equation and we show convergence of its spatial trajectory to a multiple of Brownian motion with exponential scaling. The asymptotic position of the particle is finite in mean, even though its absolute value is typically infinite. This is contrasted to an approximation that neglects the influence of fluctuations, where the mean asymptotic position is infinite.

Roland Bauerschmidt; Wojciech de Roeck; Jürg Fröhlich

2014-03-23T23:59:59.000Z

324

Radiative friction on an excited atom moving in vacuum  

E-Print Network [OSTI]

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.

Wei Guo

2012-04-30T23:59:59.000Z

325

Damping of Neutron Star Shear Modes by Superfluid Friction  

E-Print Network [OSTI]

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.

P. B. Jones

2003-01-07T23:59:59.000Z

326

Frictional dissipation of polymeric solids vs interfacial glass transition  

E-Print Network [OSTI]

We present single contact friction experiments between a glassy polymer and smooth silica substrates grafted with alkylsilane layers of different coverage densities and morphologies. This allows us to adjust the polymer/substrate interaction strength. We find that, when going from weak to strong interaction, the response of the interfacial junction where shear localizes evolves from that of a highly viscous threshold fluid to that of a plastically deformed glassy solid. This we analyse as resulting from an interaction-induced ``interfacial glass transition'' helped by pressure.

Lionel Bureau; Christiane Caroli; Tristan Baumberger

2006-07-19T23:59:59.000Z

327

Evaluation of friction loss in flexible and galvanized duct  

E-Print Network [OSTI]

/d ratios ranging from 1 to 5. Statistical analysis of the data indicated that there was a difference in the equivalent length mean data and that the interaction between r/d ratio and duct size, r/d ratio and duct type, and duct type and duct size.... . . 51 APPENDIX F ADC STANDARD REPORTING FORMS ()E AND ()E(M). . . 55 APPENDIX G EQUATIONS UTILIZED TO CONVERT FRICTION LOSS DATA TO EQUIVALENT LENGTHS APPENDIX H 58 RESULTS FROM AIR FLOW VOLUME REPRODUCIBILITY TEST. APPENDIX I 61 DATA...

Zimmermann, Carlos Michael Alberto

1985-01-01T23:59:59.000Z

328

Heat pump system  

DOE Patents [OSTI]

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.

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

1982-01-01T23:59:59.000Z

329

Water and Space Heating Heat Pumps  

E-Print Network [OSTI]

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...

Kessler, A. F.

1985-01-01T23:59:59.000Z

330

Industrial Waste Heat Recovery Using Heat Pipes  

E-Print Network [OSTI]

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...

Ruch, M. A.

1981-01-01T23:59:59.000Z

331

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

SciTech Connect (OSTI)

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.

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

2006-03-31T23:59:59.000Z

332

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

SciTech Connect (OSTI)

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.

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

2012-04-16T23:59:59.000Z

333

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

SciTech Connect (OSTI)

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.

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

2014-05-01T23:59:59.000Z

334

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

SciTech Connect (OSTI)

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.

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

335

Precipitate stability and recrystallisation in the weld nuggets of friction stir welded Al-Mg-Si and Al-Mg-Sc alloys.  

E-Print Network [OSTI]

1 Precipitate stability and recrystallisation in the weld nuggets of friction stir welded Al Two different precipitate hardening aluminium alloys processed by friction stir welding were of continuous and discontinuous recrystallisation occurred in the weld nugget. Keywords friction stir welding

Paris-Sud XI, Université de

336

Heating systems for heating subsurface formations  

DOE Patents [OSTI]

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.

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

2011-04-26T23:59:59.000Z

337

Friction Stir Spot Welding of DP780 Carbon Steel  

SciTech Connect (OSTI)

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.

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

338

Micro-origin of Macro-strength: Friction  

E-Print Network [OSTI]

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.

Alex X. Jerves; José E. Andrade

2012-12-11T23:59:59.000Z

339

SECULAR DYNAMICAL ANTI-FRICTION IN GALACTIC NUCLEI  

SciTech Connect (OSTI)

We identify a gravitational-dynamical process in near-Keplerian potentials of galactic nuclei that occurs when an intermediate-mass black hole (IMBH) is migrating on an eccentric orbit through the stellar cluster towards the central supermassive black hole. We find that, apart from conventional dynamical friction, the IMBH experiences an often much stronger systematic torque due to the secular (i.e., orbit-averaged) interactions with the cluster's stars. The force which results in this torque is applied, counterintuitively, in the same direction as the IMBH's precession and we refer to its action as 'secular dynamical anti-friction' (SDAF). We argue that SDAF, and not the gravitational ejection of stars, is responsible for the IMBH's eccentricity increase seen in the initial stages of previous N-body simulations. Our numerical experiments, supported by qualitative arguments, demonstrate that (1) when the IMBH's precession direction is artificially reversed, the torque changes sign as well, which decreases the orbital eccentricity; (2) the rate of eccentricity growth is sensitive to the IMBH migration rate, with zero systematic eccentricity growth for an IMBH whose orbit is artificially prevented from inward migration; and (3) SDAF is the strongest when the central star cluster is rapidly rotating. This leads to eccentricity growth/decrease for the clusters rotating in the opposite/same direction relative to the IMBH's orbital motion.

Madigan, Ann-Marie; Levin, Yuri, E-mail: madigan@strw.leidenuniv.nl [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands)

2012-07-20T23:59:59.000Z

340

Residual Toxicities of Insecticides to Cotton Insects.  

E-Print Network [OSTI]

the effects of simulated wind and rain on the residues. Tempera- ture and humidity conditions incident to the holding period were sufficient to destroy most of the residual toxicity of this material. Effect of Simulated Wind Among the chlorinated... hydrocarbon insecticides, there was little difference between the effects of simu- lated wind and rain on residual toxicities. However, it is likely that under field conditions the effects of rain would be more noticeable. Simulated wind was less damaging...

Hightower, B. G.; Gaines, J. C.

1960-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Heat exchanger  

DOE Patents [OSTI]

A heat exchanger comparising a shell attached at its open end to one side of a tube sheet and a detachable head connected to the other side of said tube sheet. The head is divided into a first and second chamber in fluid communication with a nozzle inlet and nozzle outlet, respectively, formed in said tube sheet. A tube bundle is mounted within said shell and is provided with inlets and outlets formed in said tube sheet in communication with said first and second chambers, respectively.

Brackenbury, P.J.

1983-12-08T23:59:59.000Z

342

Heat exchanger  

DOE Patents [OSTI]

A heat exchanger comparising a shell attached at its open end to one side of a tube sheet and a detachable head connected to the other side of said tube sheet. The head is divided into a first and second chamber in fluid communication with a nozzle inlet and nozzle outlet, respectively, formed in said tube sheet. A tube bundle is mounted within said shell and is provided with inlets and outlets formed in said tube sheet in communication with said first and second chambers, respectively.

Brackenbury, Phillip J. (Richland, WA)

1986-01-01T23:59:59.000Z

343

Methods of separating particulate residue streams  

DOE Patents [OSTI]

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.

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

344

Particulate residue separators for harvesting devices  

SciTech Connect (OSTI)

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.

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

2010-06-29T23:59:59.000Z

345

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

E-Print Network [OSTI]

Frictional powders: Ratcheting under periodic strain in 3D S. Luding1 , C. T. David2 , R. Garcia the (deviatoric) stress- strain relation a ratchet-like behavior is observed: Increasing the coefficient of friction leads to a transition from ratcheting to shake-down, i.e., the accumulation of strain stops

Luding, Stefan

346

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

E-Print Network [OSTI]

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

Cambridge, University of

347

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

E-Print Network [OSTI]

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

Cambridge, University of

348

Critical assessment: friction stir welding of H. K. D. H. Bhadeshia*1  

E-Print Network [OSTI]

Critical assessment: friction stir welding of steels H. K. D. H. Bhadeshia*1 and T. DebRoy2 The level of activity in research on the friction stir welding of steels is dwarfed when compared of Welding and Joining is to assess the state of the art, focusing on the knowledge base in the open

Cambridge, University of

349

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

E-Print Network [OSTI]

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

Grujicic, Mica

350

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

E-Print Network [OSTI]

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

Cambridge, University of

351

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

E-Print Network [OSTI]

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

Grujicic, Mica

352

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

E-Print Network [OSTI]

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

Grujicic, Mica

353

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

E-Print Network [OSTI]

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

Norris, Andrew

354

High-resolution friction force microscopy under electrochemical control Aleksander Labuda,1  

E-Print Network [OSTI]

High-resolution friction force microscopy under electrochemical control Aleksander Labuda,1 William and development of a friction force microscope for high-resolution studies in electrochemical environments in liquids. The noise of the system is analyzed based on a methodology for the quantification of all

GrĂĽtter, Peter

355

A phenomenological model to describe turbulent friction in permeable-wall flows  

E-Print Network [OSTI]

A phenomenological model to describe turbulent friction in permeable-wall flows C. Manes,1 L impermeable rough boundaries. A novel phenomenological model that describes such anomalous behavior), A phenomenological model to describe tur- bulent friction in permeable-wall flows, Geophys. Res. Lett., 39, L14403

Katul, Gabriel

356

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

E-Print Network [OSTI]

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

Papadopoulos, Evangelos

357

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

E-Print Network [OSTI]

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

Demirel, Melik C.

358

TEXTURE-INDUCED CAVITATION BUBBLES AND FRICTION REDUCTION IN THE ELROD-ADAMS MODEL  

E-Print Network [OSTI]

TEXTURE-INDUCED CAVITATION BUBBLES AND FRICTION REDUCTION IN THE ELROD-ADAMS MODEL Hugo M. Checoa, Friction reduction, Cavitation, Numerical simulation. Symbol Description a, b the pad occupies the region of textures µ dynamic viscosity cavitation boundary 0 cavitated region + pressurized region 1 INTRODUCTION

Buscaglia, Gustavo C.

359

Finite Element Analysis of the Amontons-Coulomb's Model using Local and Global Friction Tests  

SciTech Connect (OSTI)

In spite of the abundant number of experimental friction tests that have been reported, the contact with friction modeling persists to be one of the factors that determine the effectiveness of sheet metal forming simulation. This difficulty can be understood due to the nature of the friction phenomena, which comprises the interaction of different factors connected to both sheet and tools' surfaces. Although in finite element numerical simulations friction models are commonly applied at the local level, they normally rely on parameters identified based on global experimental tests results. The aim of this study is to analyze the applicability of the Amontons-Coulomb's friction coefficient identified using complementary tests: (i) load-scanning, at the local level and (ii) draw-bead, at the global level; to the numerical simulation of sheet metal forming processes.

Oliveira, M. C.; Menezes, L. F.; Ramalho, A. [CEMUC, Department of Mechanical Engineering, University of Coimbra, Polo II, Rua Luis Reis Santos, Pinhal de Marrocos, 3030-788 Coimbra (Portugal); Alves, J. L. [Department of Mechanical Engineering, University of Minho, Campus de Azurem, 4800-058, Guimaraes (Portugal)

2011-05-04T23:59:59.000Z

360

Looping and reconfiguration dynamics of a flexible chain with internal friction  

E-Print Network [OSTI]

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.

Nairhita Samanta; Jayanta Ghosh; Rajarshi Chakrabarti

2014-04-09T23:59:59.000Z

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

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

SciTech Connect (OSTI)

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).

Murray, A.M.

1999-02-10T23:59:59.000Z

362

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

SciTech Connect (OSTI)

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.

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

2005-09-30T23:59:59.000Z

363

Dual source heat pump  

DOE Patents [OSTI]

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.

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

1982-01-01T23:59:59.000Z

364

Segmented heat exchanger  

DOE Patents [OSTI]

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.

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

365

Friction Stir Welding of Mild Steel -Tool Durability and Steel Microstructure , H. K. D. H. Bhadeshia2  

E-Print Network [OSTI]

1" " Friction Stir Welding of Mild Steel - Tool Durability and Steel Microstructure A. De1 , H. K in the context of welding difficult aluminium alloys. We now apply this scheme to the friction stir welding and the consequences on the physical metallurgy of the steel. Introduction Friction stir welding (FSW) of aluminium

Cambridge, University of

366

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

E-Print Network [OSTI]

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

Texas at Austin. University of

367

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

E-Print Network [OSTI]

Friction anisotropy at Ni,,100...Ă?,,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

Goddard III, William A.

368

Friction-induced vibration of a lubricated mechanical system J-J. Sinou*, J. Cayer-Barrioz and H. Berro  

E-Print Network [OSTI]

1 Friction-induced vibration of a lubricated mechanical system J-J. Sinou*, J. Cayer-Barrioz and H that incorporates realistic laws of local friction issued from previous experimental results. The objective or by themselves, such as friction-induced vibrations. In all cases, these vibrations are hardly controllable

Paris-Sud XI, Université de

369

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

E-Print Network [OSTI]

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

Tsiotras, Panagiotis

370

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

E-Print Network [OSTI]

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

Texas at Austin. University of

371

Friction Stir Welding Download the files fswss.txt and fswdyn.txt from the course website. These files contain  

E-Print Network [OSTI]

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

Landers, Robert G.

372

October 14 WA Division Newsletter Page 4 Tool durability and steel microstructure in friction stir welding of mild steel  

E-Print Network [OSTI]

scheme to assess tool durability and tool life in the friction stir welding (FSW) of difficult alumin referencing is freely avail- able at: http://tinyurl.com/mst-fsw. Tools for friction stir welding (FSWOctober 14 WA Division Newsletter Page 4 Tool durability and steel microstructure in friction stir

Cambridge, University of

373

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

SciTech Connect (OSTI)

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.

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

374

Asymptotics for GARCH Squared Residual Correlations  

E-Print Network [OSTI]

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

Kokoszka, Piotr

375

University of Pittsburgh Residual Funds on  

E-Print Network [OSTI]

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

Sibille, Etienne

376

Data Conversion in Residue Number System  

E-Print Network [OSTI]

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

Zilic, Zeljko

377

Energy conversion device and method of reducing friction therein  

DOE Patents [OSTI]

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.

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

378

Dynamical friction of radio galaxies in galaxy clusters  

E-Print Network [OSTI]

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.

Biman B. Nath

2008-04-22T23:59:59.000Z

379

Lateral vibration effects in atomic-scale friction  

SciTech Connect (OSTI)

The influence of lateral vibrations on the stick-slip motion of a nanotip elastically pulled on a flat crystal surface is studied by atomic force microscopy measurements on a NaCl(001) surface in ultra-high vacuum. The slippage of the nanotip across the crystal lattice is anticipated at increasing driving amplitude, similarly to what is observed in presence of normal vibrations. This lowers the average friction force, as explained by the Prandtl-Tomlinson model with lateral vibrations superimposed at finite temperature. Nevertheless, the peak values of the lateral force, and the total energy losses, are expected to increase with the excitation amplitude, which may limit the practical relevance of this effect.

Roth, R. [Climate and Environment Physics, Physics Institute, University of Bern, Bern (Switzerland); Oeschger Centre for Climate Change Research, University of Bern, Bern (Switzerland); Fajardo, O. Y.; Mazo, J. J. [Departamento de Física de la Materia Condensada and Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, 50009 Zaragoza (Spain); Meyer, E. [Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel (Switzerland); Gnecco, E. [Instituto Madrileńo de Estudios Avanzados en Nanociencia, IMDEA Nanociencia, 28049 Madrid (Spain)

2014-02-24T23:59:59.000Z

380

Single-friction-surface triboelectric generator with human body conduit  

SciTech Connect (OSTI)

We present a transparent single-friction-surface triboelectric generator (STEG) employing human body as the conduit, making the applications of STEG in portable electronics much more practical and leading to a significant output improvement. The STEG with micro-patterned polydimethylsiloxane surface achieved an output voltage of over 200 V with a current density of 4.7 ?A/cm{sup 2}. With human body conduit, the output current increased by 39% and the amount of charge that transferred increased by 34% compared to the results with grounded electrode. A larger increment of 210% and 81% was obtained in the case of STEG with a large-size flat polyethylene terephthalate surface.

Meng, Bo; Cheng, Xiaoliang; Zhang, Xiaosheng; Han, Mengdi; Liu, Wen; Zhang, Haixia, E-mail: zhang-alice@pku.edu.cn [National Key Lab of Nano/Micro Fabrication Technology, Peking University, Beijing 100871 (China)] [National Key Lab of Nano/Micro Fabrication Technology, Peking University, Beijing 100871 (China)

2014-03-10T23:59:59.000Z

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Lateral position detection and control for friction stir systems  

DOE Patents [OSTI]

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.

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

382

Multiple source heat pump  

DOE Patents [OSTI]

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.

Ecker, Amir L. (Duncanville, TX)

1983-01-01T23:59:59.000Z

383

A frictional model of a two-port unbounded ocean basin  

E-Print Network [OSTI]

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...

Wert, Richard Thomas

1968-01-01T23:59:59.000Z

384

Ultra low friction carbon/carbon composites for extreme temperature applications  

DOE Patents [OSTI]

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

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

385

Surface energy budget over the South Pole and turbulent heat fluxes as a function of an empirical bulk Richardson number  

E-Print Network [OSTI]

Surface energy budget over the South Pole and turbulent heat fluxes as a function of an empirical in the monthly mean surface energy budget and to investigate the behavior of turbulent heat fluxes under stable and one as the residual of the surface energy budget (i.e., subsurface heat fluxes minus net radiation

Walden, Von P.

386

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]

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

Roy, Subrata

387

Heat Pump for High School Heat Recovery  

E-Print Network [OSTI]

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...

Huang, K.; Wang, H.; Zhou, X.

2006-01-01T23:59:59.000Z

388

Microstructural Examination to Aid in Understanding Friction Bonding Fabrication Technique for Monolithic Nuclear Fuel  

SciTech Connect (OSTI)

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.

Karen L. Shropshire

2008-04-01T23:59:59.000Z

389

Combined Heat and Power, Waste Heat, and District Energy | Department...  

Broader source: Energy.gov (indexed) [DOE]

Combined Heat and Power, Waste Heat, and District Energy Combined Heat and Power, Waste Heat, and District Energy Presentation-given at the Fall 2011 Federal Utility Partnership...

390

Project Profile: Heat Transfer and Latent Heat Storage in Inorganic...  

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

Heat Transfer and Latent Heat Storage in Inorganic Molten Salts for CSP Plants Project Profile: Heat Transfer and Latent Heat Storage in Inorganic Molten Salts for CSP Plants...

391

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...

392

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...

393

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,...

394

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...

395

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...

396

Residual stress in nanocrystalline nickel tungsten electrodeposits  

E-Print Network [OSTI]

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 ...

Ziebell, Tiffany D. (Tiffany Dawn)

2011-01-01T23:59:59.000Z

397

SAR impulse response with residual chirps.  

SciTech Connect (OSTI)

A Linear Frequency-Modulated (LFM) chirp is a function with unit amplitude and quadratic phase characteristic. In a focused Synthetic Aperture Radar (SAR) image, a residual chirp is undesired for targets of interest, as it coarsens the manifested resolution. However, for undesired spurious signals, a residual chirp is often advantageous because it spreads the energy and thereby diminishes its peak value. In either case, a good understanding of the effects of a residual LFM chirp on a SAR Impulse Response (IPR) is required to facilitate system analysis and design. This report presents an analysis of the effects of a residual chirp on the IPR. As reference, there is a rich body of publications on various aspects of LFM chirps. A quick search reveals a plethora of articles, going back to the early 1950s. We mention here purely as trivia one of the earlier analysis papers on this waveform by Klauder, et al.

Doerry, Armin Walter

2009-06-01T23:59:59.000Z

398

Diagnosing residual motion via the x-ray self emission from indirectly driven inertial confinement implosions  

SciTech Connect (OSTI)

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.

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

399

Absorption heat pump system  

DOE Patents [OSTI]

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.

Grossman, G.

1982-06-16T23:59:59.000Z

400

Locating Heat Recovery Opportunities  

E-Print Network [OSTI]

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...

Waterland, A. F.

1981-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Absorption heat pump system  

DOE Patents [OSTI]

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.

Grossman, Gershon (Oak Ridge, TN)

1984-01-01T23:59:59.000Z

402

Woven heat exchanger  

DOE Patents [OSTI]

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.

Piscitella, R.R.

1984-07-16T23:59:59.000Z

403

In situ control of lubricant properties for reduction of power cylinder friction through thermal barrier coating  

E-Print Network [OSTI]

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 ...

Molewyk, Mark Allen

2014-01-01T23:59:59.000Z

404

Experimental investigation of energy dissipation behavior of the modified friction device  

E-Print Network [OSTI]

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) ...

Zahner, Robert Marne

2011-01-01T23:59:59.000Z

405

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

E-Print Network [OSTI]

Complex Non-Linear Modal Analysis for Mechanical Systems: Application to Turbomachinery Bladings of a turbomachinery blade, with dry-friction interfaces is proposed. In the latter, an original framework

Paris-Sud XI, Université de

406

Micro and nano mechanics of materials response during instrumented frictional sliding  

E-Print Network [OSTI]

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 ...

Bellemare, Simon C. (Simon Claude)

2006-01-01T23:59:59.000Z

407

The Role of Friction Stir Welding in Nuclear Fuel Plate Fabrication  

SciTech Connect (OSTI)

The friction bonding process combines desirable attributes of both friction stir welding and friction stir processing. The development of the process is spurred on by the need to fabricate thin, high density, reduced enrichment fuel plates for nuclear research reactors. The work seeks to convert research and test reactors currently operating on highly enriched uranium fuel to operate on low enriched uranium fuel without significant loss in reactor performance, safety characteristics, or significant increase in cost. In doing so, the threat of global nuclear material proliferation will be reduced. Feasibility studies performed on the process show that this is a viable option for mass production of plate-type nuclear fuel. Adapting the friction stir weld process for nuclear fuel fabrication has resulted in the development of several unique ideas and observations. Preliminary results of this adaptation and process model development are discussed.

D Burkes; P Medvedev; M Chapple; A Amritkar; P Wells; I Charit

2009-02-01T23:59:59.000Z

408

Defining the role of elastic lubricants and micro textured surfaces in lubricated, sliding friction  

E-Print Network [OSTI]

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 ...

Hupp, Sara J. (Sara Jean), 1979-

2008-01-01T23:59:59.000Z

409

Forced Response Analysis of Integrally Bladed Disks with Friction Ring Dampers  

E-Print Network [OSTI]

is proposed. In numerical applications, a representative compressor blisk featuring several rings the wheel of blisks. These are held in contact with the blisk due to centrifugal loads and friction

Boyer, Edmond

410

Experimental and Theoretical Investigations of Lube Oil Performance and Engine Friction.  

E-Print Network [OSTI]

??The feasibility of using a motored small, single-cylinder 517 cc Hatz 1D50 diesel engine to evaluate lube oil performance and engine friction at conditions typical… (more)

Rohr, William Fredrick

2013-01-01T23:59:59.000Z

411

Friction and Adhesion Forces of Bacillus thuringiensis Spores on Planar Surfaces in Atmospheric Systems  

SciTech Connect (OSTI)

The kinetic friction force and the adhesion force of Bacillus thuringiensis spores on planar surfaces in atmospheric systems were studied using atomic force microscopy. The influence of relative humidity (RH) on these forces varied for different surface properties including hydrophobicity, roughness, and surface charge. The friction force of the spore was greater on a rougher surface than on mica, which is atomically flat. As RH increases, the friction force of the spores decreases on mica whereas it increases on rough surfaces. The influence of RH on the interaction forces between hydrophobic surfaces is not as strong as for hydrophilic surfaces. The friction force of the spore is linear to the sum of the adhesion force and normal load on the hydrophobic surface. The poorly defined surface structure of the spore and the adsorption of contaminants from the surrounding atmosphere are believed to cause a discrepancy between the calculated and measured adhesion forces.

Kweon, Hyojin [Georgia Institute of Technology; Yiacoumi, Sotira [Georgia Institute of Technology; Tsouris, Costas [ORNL

2011-01-01T23:59:59.000Z

412

Low-Engine-Friction Technology for Advanced Natural-Gas Reciprocating Engines  

SciTech Connect (OSTI)

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.

Victor Wong; Tian Tian; G. Smedley; L. Moughon; Rosalind Takata; J. Jocsak

2006-11-30T23:59:59.000Z

413

Experimental study of friction noise of dry contact under light load  

E-Print Network [OSTI]

musical instruments such as violins, guitars, sound radiated by glass when rubbing a moist finger, tyres on frictional sound may also be mentioned (Othman et al., 1990-1) and an original device for measuring

Le-Bot, Alain

414

Method for measuring residual stresses in materials by plastically deforming the material and interference pattern comparison  

DOE Patents [OSTI]

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.

Pechersky, Martin J. (241 Chardonnat La., Aiken, SC 29803)

1995-01-01T23:59:59.000Z

415

Thermal input control and enhancement for laser based residual stress measurements using liquid temperature indicating coatings  

DOE Patents [OSTI]

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.

Pechersky, M.J.

1999-07-06T23:59:59.000Z

416

Thermal input control and enhancement for laser based residual stress measurements using liquid temperature indicating coatings  

DOE Patents [OSTI]

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.

Pechersky, Martin J. (Aiken, SC)

1999-01-01T23:59:59.000Z

417

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...

418

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...

419

Towards Intelligent District Heating.  

E-Print Network [OSTI]

??A district heating system consists of one or more production units supplying energy in the form of heated water through a distribution pipe network to… (more)

Johansson, Christian

2010-01-01T23:59:59.000Z

420

Winter Heating Fuels Update  

Gasoline and Diesel Fuel Update (EIA)

Heating Fuels Update For: Congressional Briefings October 20, 2014 | Washington, DC By U.S. Energy Information Administration Winter Heating Fuels Update October 20, 2014 |...

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Friction stir welding and processing of oxide dispersion strengthened (ODS) alloys  

DOE Patents [OSTI]

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.

Ren, Weiju

2014-11-11T23:59:59.000Z

422

Hard and low friction nitride coatings and methods for forming the same  

DOE Patents [OSTI]

An improved coating material possessing super-hard and low friction properties and a method for forming the same. The improved coating material includes the use of a noble metal or soft metal homogeneously distributed within a hard nitride material. The addition of small amounts of such metals into nitrides such as molybdenum nitride, titanium nitride, and chromium nitride results in as much as increasing of the hardness of the material as well as decreasing the friction coefficient and increasing the oxidation resistance.

Erdemir, Ali (Naperville, IL); Urgen, Mustafa (Istanbul, TR); Cakir, Ali Fuat (Istanbul, TR); Eryilmaz, Osman Levent (Bolingbrook, IL); Kazmanli, Kursat (Istanbul, TR); Keles, Ozgul (Istanbul, TR)

2007-05-01T23:59:59.000Z

423

Friction welded nonconsumable electrode assembly and use thereof for electrolytic production of metals and silicon  

DOE Patents [OSTI]

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.

Byrne, Stephen C. (Monroeville, PA); Ray, Siba P. (Pittsburgh, PA); Rapp, Robert A. (Columbus, OH)

1984-01-01T23:59:59.000Z

424

Stellite 6 Friction Changes Due to Aging and In-Service Testing  

SciTech Connect (OSTI)

For the past several years, researchers at the Idaho National Engineering and Environmental Laboratory, under the sponsorship of the U.S. Nuclear Regulatory Commission, have been investigating the ability of motor-operated valves to close or open when subjected to design basis flow and pressure loads. Part of this research addresses the friction that occurs at the interface between the valve disc and the valve body seats during operation of a gate valve. In most gate valves, these surfaces are hardfaced with Stellite 6, a cobalt-based alloy. The nuclear industry has developed methods to analytically predict the thrust needed to operate these valves at specific pressure conditions. To produce accurate valve thrust predictions; the analyst must have a reasonably accurate, though conservative, estimate of the coefficient of friction at the disc-to-seat interface. One of the questions that remains to be answered is whether, and to what extent, aging of the disc and seat surfaces affects the disc-to-seat coefficient of friction. Specifically, does the accumulation of a surface film due to aging of these surfaces increase the coefficient of friction and if so, how much? This paper presents results of specimen tests addressing this issue with emphasis on the following: • The change in the friction coefficient of Stellite 6 as it ages and whether the friction reaches a plateau. • The effect periodic gate valve cycling due to in-service testing has on the friction coefficient. • The results of an independent review of the test methods, processes, and the results of the research to date. • The status of ongoing aging and friction testing.

Watkins, John Clifford; DeWall, Kevin George

2001-07-01T23:59:59.000Z

425

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

E-Print Network [OSTI]

FRICTION COEFFICIENTS OF SORGHUM GRAIN ON STEEL, TEFLON, AND CONCRETE SURFACES A Thesis By QUAZI ANWAR HOSSAIN Submitted to the Graduate College of the Texas A6M University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE January 1967 Major Subject: Agricultural Engineering FRICTION COEFFICIENTS OF SORGHUM GRMN ON STEEL, TEFLON, AND CONCRETE SURFACES A Thesis By QUAZI ANWAR HOSSAIN Approved as to style and content by: (Chairma Com ' ee) ead o D'epart nt...

Hossain, Quazi A

1967-01-01T23:59:59.000Z

426

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...

427

Electric force microscopy of semiconductors: Theory of cantilever frequency fluctuations and noncontact friction  

SciTech Connect (OSTI)

An electric force microscope employs a charged atomic force microscope probe in vacuum to measure fluctuating electric forces above the sample surface generated by dynamics of molecules and charge carriers. We present a theoretical description of two observables in electric force microscopy of a semiconductor: the spectral density of cantilever frequency fluctuations (jitter), which are associated with low-frequency dynamics in the sample, and the coefficient of noncontact friction, induced by higher-frequency motions. The treatment is classical-mechanical, based on linear response theory and classical electrodynamics of diffusing charges in a dielectric continuum. Calculations of frequency jitter explain the absence of contributions from carrier dynamics to previous measurements of an organic field effect transistor. Calculations of noncontact friction predict decreasing friction with increasing carrier density through the suppression of carrier density fluctuations by intercarrier Coulomb interactions. The predicted carrier density dependence of the friction coefficient is consistent with measurements of the dopant density dependence of noncontact friction over Si. Our calculations predict that in contrast to the measurement of cantilever frequency jitter, a noncontact friction measurement over an organic semiconductor could show appreciable contributions from charge carriers.

Lekkala, Swapna; Marohn, John A.; Loring, Roger F., E-mail: roger.loring@cornell.edu [Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853 (United States)

2013-11-14T23:59:59.000Z

428

Enhancing trappable antiproton populations through deceleration and frictional cooling  

SciTech Connect (OSTI)

CERN currently delivers antiprotons for trapping experiments with the Antiproton Decelerator (AD), which slows the antiprotons down to about 5 MeV.This energy is currently too high for direct trapping, and thick foils are used to slow down the beam to energies which can be trapped.To allow further deceleration to $\\sim 100 \\;\\mbox{keV}$, CERN is initiating the construction of ELENA,consisting of a ring which will combine RF deceleration and electron cooling capabilities. We describe a simple frictionalcooling scheme that can serve to provide significantly improved trapping efficiency, either directly from the AD or first usinga standard deceleration mechanism (induction linac or RFQ). This scheme could be implemented in a short time.The device itself is short in length, uses accessible voltages, and at reasonable cost could serve in the interim beforeELENA becomes operational, or possibly in lieu of ELENA for some experiments. Simple theory and simulations provide a preliminary assessment of theconcept and its strengths and limitations, and highlight important areas for experimental studies, in particular to pin down the level of multiplescattering for low-energy antiprotons. We show that the frictional cooling scheme can provide a similar energy spectrum to that of ELENA,but with higher transverse emittances.

Zolotorev, Max; Sessler, Andrew; Penn, Gregory; Wurtele, Jonathan S.; Charman, Andrew E.

2012-03-20T23:59:59.000Z

429

Dynamical Friction and Resonance Trapping in Planetary Systems  

E-Print Network [OSTI]

A restricted planar circular three-body system, consisting of the Sun and two planets, is studied as a simple model for a planetary system. The mass of the inner planet is considered to be larger and the system is assumed to be moving in a uniform interplanetary medium with constant density. Numerical integrations of this system indicate a resonance capture when the dynamical friction of the interplanetary medium is taken into account. As a result of this resonance trapping, the ratio of orbital periods of the two planets becomes nearly commensurate and the eccentricity and semimajor axis of the orbit of the outer planet and also its angular momentum and total energy become constant. It appears from the numerical work that the resulting commensurability and also the resonant values of the orbital elements of the outer planet are essentially independent of the initial relative positions of the two bodies. The results of numerical integrations of this system are presented and the first-order partially averaged equations are studied in order to elucidate the behavior of the system while captured in resonance.

Nader Haghighipour

1998-12-05T23:59:59.000Z

430

CONDENSATION/ADSORPTION AND EVACUATION OF RESIDUAL GASES IN THE SRF SYSTEM FOR THE CESR LUMINOSITY UPGRADE  

E-Print Network [OSTI]

cavity RBT transition HOM absorber FBT transition Nb waveguide Heat exchanger 270 l/s ion pump RF windowCONDENSATION/ADSORPTION AND EVACUATION OF RESIDUAL GASES IN THE SRF SYSTEM FOR THE CESR LUMINOSITY coupler performance in a superconducting RF system. It is there- fore important to understand condensation/adsorption

Geng, Rong-Li

431

Sustainable System for Residual Hazards Management  

SciTech Connect (OSTI)

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.

Kevin M. Kostelnik; James H. Clarke; Jerry L. Harbour

2004-06-01T23:59:59.000Z

432

Heavy Truck Friction & Wear Reduction Technologies | Department of Energy  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensional Subject:Ground Hawaii CleanHeat Pump WaterPresentation

433

Rotary magnetic heat pump  

DOE Patents [OSTI]

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.

Kirol, L.D.

1987-02-11T23:59:59.000Z

434

Mass and Heat Recovery  

E-Print Network [OSTI]

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...

Hindawai, S. M.

2010-01-01T23:59:59.000Z

435

Direct fired heat exchanger  

SciTech Connect (OSTI)

A gas-to-liquid heat exchanger system which transfers heat from a gas, generally the combustion gas of a direct-fired generator of an absorption machine, to a liquid, generally an absorbent solution. The heat exchanger system is in a counterflow fluid arrangement which creates a more efficient heat transfer.

Reimann, Robert C. (Lafayette, NY); Root, Richard A. (Spokane, WA)

1986-01-01T23:59:59.000Z

436

Rotary magnetic heat pump  

DOE Patents [OSTI]

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.

Kirol, Lance D. (Shelly, ID)

1988-01-01T23:59:59.000Z

437

Thulium-170 heat source  

DOE Patents [OSTI]

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.

Walter, Carl E. (Pleasanton, CA); Van Konynenburg, Richard (Livermore, CA); VanSant, James H. (Tracy, CA)

1992-01-01T23:59:59.000Z

438

Heat Treating Apparatus  

DOE Patents [OSTI]

Apparatus for heat treating a heat treatable material including a housing having an upper opening for receiving a heat treatable material at a first temperature, a lower opening, and a chamber therebetween for heating the heat treatable material to a second temperature higher than the first temperature as the heat treatable material moves through the chamber from the upper to the lower opening. A gas supply assembly is operatively engaged to the housing at the lower opening, and includes a source of gas, a gas delivery assembly for delivering the gas through a plurality of pathways into the housing in countercurrent flow to movement of the heat treatable material, whereby the heat treatable material passes through the lower opening at the second temperature, and a control assembly for controlling conditions within the chamber to enable the heat treatable material to reach the second temperature and pass through the lower opening at the second temperature as a heated material.

De Saro, Robert (Annandale, NJ); Bateman, Willis (Sutton Colfield, GB)

2002-09-10T23:59:59.000Z

439

BY HOW MUCH CAN RESIDUAL MINIMIZATION ACCELERATE THE CONVERGENCE OF ORTHOGONAL RESIDUAL METHODS?  

E-Print Network [OSTI]

. 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

Gutknecht, Martin H.

440

Thermoelectric heat exchange element  

DOE Patents [OSTI]

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.

Callas, James J. (Peoria, IL); Taher, Mahmoud A. (Peoria, IL)

2007-08-14T23:59:59.000Z

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Measurement of local internal friction in metallic glasses  

SciTech Connect (OSTI)

Atomic force acoustic microscopy (AFAM), an advanced scanning probe microscopy technique, has been used to measure local elastic properties with a spatial resolution given by the tip-sample contact radius. AFAM is based on inducing out-of-plane vibrations in the specimen. The vibrations are sensed by the AFM cantilever from by the photodiode signal when its tip is in contact with the material under test. To measure local damping, the inverse quality factor Q{sup ?1} of the resonance curve is usually evaluated. Here, from the contact-resonance spectra obtained, we determine the real and imaginary part of the contact stiffness k* and from these two quantities the local damping factor Q{sub loc}{sup ?1} is obtained which is proportional to the imaginary part ? of the contact stiffness. The evaluation of the data is based on the cantilever's mass distribution with damped flexural modes and not on an effective point-mass approximation for the cantilever’s motion. The given equation is simple to use and has been employed to study the local Q{sub loc}{sup ?1} of amorphous PdCuSi metallic glass and its crystalline counterpart as a function of position of the AFM tip on the surface. The width of the distribution changes dramatically from the amorphous to the crystalline state as expected from the consequences of the potential-energy landscape picture. The center value of the distribution curve for Q{sub loc}{sup ?1} coincides very well with published data, based on global ultrasonic or internal friction measurements. This is compared to Q{sub loc}{sup ?1} measured in crystalline SrTiO{sub 3}, which exhibits a narrow distribution, as expected.

Wagner, H.; Büchsenschütz-Göbeler, M.; Luo, Y.; Samwer, K. [I. Physikalisches Institut, Georg-August Universität, Friedrich-Hund-Platz 1, D-37077 Göttingen (Germany); Kumar, A. [Metallurgy and Materials Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India); Arnold, W., E-mail: w.arnold@mx.uni-saarland.de [I. Physikalisches Institut, Georg-August Universität, Friedrich-Hund-Platz 1, D-37077 Göttingen (Germany); Department of Materials and Materials Technology, Saarland University, Campus D 2.2, D-66123 Saarbrücken (Germany)

2014-04-07T23:59:59.000Z

442

Heat Integrate Heat Engines in Process Plants  

E-Print Network [OSTI]

of forcing a good fit between a heat engine and process T', H profiles extends the ideas of appropriate and inappropriate placement to give bet ter overall integration schemes [7] . The new 'and powerful representations of the thermodynamics of a process... HEAT INTEGRATE HEAT ENGINES IN PROCESS PLANTS E. Hindmarsh, D. Boland and D.W. Townsend TENSA Technology, Houston, Texas Shorter Version Appeared in Chemical Engineering Copyright McGraw Hill, 1985 ABSTRACT This paper presents a novel method...

Hindmarsh, E.; Boland, D.; Townsend, D. W.

443

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

SciTech Connect (OSTI)

This program aims at improving the efficiency of advanced natural-gas reciprocating engines (ANGRE) by reducing piston/ring assembly friction without major adverse effects on engine performance, such as increased oil consumption and emissions. An iterative process of simulation, experimentation and analysis, are being followed towards achieving the goal of demonstrating a complete optimized low-friction engine system. To date, a detailed set of piston/ring dynamic and friction models have been developed and applied that illustrated the fundamental relationships between design parameters and friction losses. Various low-friction strategies and ring-design concepts have been explored, and engine experiments have been done on a full-scale Waukesha VGF F18 in-line 6 cylinder power generation engine rated at 370 kW at 1800 rpm. Current accomplishments include designing and testing ring-packs using a subtle top-compression-ring profile (skewed barrel design), lowering the tension of the oil-control ring, employing a negative twist to the scraper ring to control oil consumption. Initial test data indicate that piston ring-pack friction was reduced by 35% by lowering the oil-control ring tension alone, which corresponds to a 1.5% improvement in fuel efficiency. Although small in magnitude, this improvement represents a first step towards anticipated aggregate improvements from other strategies. Other ring-pack design strategies to lower friction have been identified, including reduced axial distance between the top two rings, tilted top-ring groove. Some of these configurations have been tested and some await further evaluation. Colorado State University performed the tests and Waukesha Engine Dresser, Inc. provided technical support. Key elements of the continuing work include optimizing the engine piston design, application of surface and material developments in conjunction with improved lubricant properties, system modeling and analysis, and continued technology demonstration in an actual full-sized reciprocating natural-gas engine.

Victor W. Wong; Tian Tian; Grant Smedley; Jeffrey Jocsak

2004-09-30T23:59:59.000Z

444

Condensation in horizontal heat exchanger tubes  

SciTech Connect (OSTI)

Many innovative reactor concepts for Generation III nuclear power plants use passive safety equipment for residual heat removal. These systems use two phase natural circulation. Heat transfer to the coolant results in a density difference providing the driving head for the required mass flow. By balancing the pressure drop the system finds its operational mode. Therefore the systems depend on a strong link between heat transfer and pressure drop determining the mass flow through the system. In order to be able to analyze these kind of systems with the help of state of the art computer codes the implemented numerical models for heat transfer, pressure drop or two phase flow structure must be able to predict the system performance in a wide parameter range. Goal of the program is to optimize the numerical models and therefore the performance of computer codes analyzing passive systems. Within the project the heat transfer capacity of a heat exchanger tube will be investigated. Therefore the tube will be equipped with detectors, both temperature and pressure, in several directions perpendicular to the tube axis to be able to resolve the angular heat transfer. In parallel the flow structure of a two phase flow inside and along the tube will be detected with the help of x-ray tomography. The water cooling outside of the tube will be realized by forced convection. It will be possible to combine the flow structure measurement with an angular resolved heat transfer for a wide parameter range. The test rig is set up at the TOPLFOW facility at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), so that it will be possible to vary the pressure between 5 and 70 bar. The steam mass content will be varied between 0 and 100 percent. The results will be compared to the large scaled Emergency Condenser Tests performed at the INKA test facility in Karlstein (Germany). The paper will explain the test setup and the status of the project will be presented. (authors)

Leyer, S.; Zacharias, T.; Maisberger, F.; Lamm, M. [AREVA NP GmbH, Paul-Gossen-Strasse 100, Erlangen, 91052 (Germany); Vallee, C.; Beyer, M.; Hampel, U. [Helmholtz-Zentrum Dresden-Rossendorf e.V., Bautzner Landstrasse 400, Dresden, 01328 (Germany)

2012-07-01T23:59:59.000Z

445

Residual oil conversion in Ashland FCC Units  

SciTech Connect (OSTI)

Ashland Petroleum Company is a production-poor refining and marketing company. A company must have refining flexibility to compete in today's crude and marketing situation. Ashland has adopted a dual approach to achieving the required refining flexibility: development and construction of the RCC process, and development of techniques to practice residual oil conversion in Ashland FCC units. This paper discusses the operating techniques Ashland has used to allow residual oil conversion to be practiced in their present day FCC's and shows some of the yields which have been achieved.

Barger, D.F.; Miller, C.B.

1983-03-01T23:59:59.000Z

446

Residual dust charges in discharge afterglow  

SciTech Connect (OSTI)

An on-ground measurement of dust-particle residual charges in the afterglow of a dusty plasma was performed in a rf discharge. An upward thermophoretic force was used to balance the gravitational force. It was found that positively charged, negatively charged, and neutral dust particles coexisted for more than 1 min after the discharge was switched off. The mean residual charge for 200-nm-radius particles was measured. The dust particle mean charge is about -5e at a pressure of 1.2 mbar and about -3e at a pressure of 0.4 mbar.

Coueedel, L.; Mikikian, M.; Boufendi, L.; Samarian, A. A. [GREMI - Groupe de Recherches sur l'Energetique des Milieux Ionises, CNRS/Universite d'Orleans, 14 rue d'Issoudun, 45067 Orleans Cedex 2 (France); School of Physics A28, University of Sydney, NSW 2006 (Australia)

2006-08-15T23:59:59.000Z

447

Finite quantum dissipation: the challenge of obtaining specific heat  

E-Print Network [OSTI]

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_Dheat based on the thermodynamic prescription becomes negative. This anomaly is rooted in an ill-defined density of states of the damped free particle which assumes unphysical negative values when gamma/omega_D>1.

Peter Hänggi; Gert-Ludwig Ingold; Peter Talkner

2008-05-26T23:59:59.000Z

448

Vehicle Technologies Office Merit Review 2014: Friction Reduction through Surface Modification (Agreement ID:23284) Project ID:18518  

Broader source: Energy.gov [DOE]

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

449

Friction Modeling for Lubricated Engine and Drivetrain Components |  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensional Electrical Resistivity Structure |Accomplishments

450

Friction Stir Spot Welding of Advanced High Strength Steels (AHSS) |  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensional Electrical Resistivity Structure |AccomplishmentsDepartment of

451

Friction and Wear Enhancement of Titanium Alloy Engine Components |  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensional Electrical Resistivity StructureDepartment of Energy 1

452

Friction/Wear Â… Parasitic Energy Losses | Department of Energy  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensional Electrical Resistivity StructureDepartment of EnergyGear

453

Nondestructive, in-process inspection of inertia friction welding : an investigation into a new sensing technique.  

SciTech Connect (OSTI)

This paper investigates the capabilities of a new sensor for in-process monitoring of quality during friction welding. The non-contact sensor is composed of microphones that are mounted in an aluminum ring which surrounds the weld joint. The sensor collects the acoustical energy (in the form of sound pressure) that is emitted during the plastic deformation and phase transformations (if applicable) in friction welding processes. The focus in this preliminary investigation is to search for and identify features within the acoustical emission that are indicative of bond quality. Bar-to-bar inertia friction welding (one form of friction welding) of copper to 304L stainless steel is used in this proof-of-concept study. This material combination exhibits only marginal weldability and is ideally suited for validating the capabilities of this new sensing technique. A probabilistic neural network is employed in this work to analyze the acoustical emission's frequency spectrum in an attempt to classify acceptable, conditional, and unacceptable welds. Our preliminary findings indicate that quality-based process features do exist within the frequency spectrum of the acoustical signature. The results from this analysis are presented. Future work in improving the sensing and interpretation of the data is discussed in an effort to develop a robust method of quality-based, in-process monitoring of friction welds.

Hartman, D. A. (Daniel A.); Cola, M. J. (Mark J.); Dave, V. R. (Vivek R.); Dozhier, N. G. (Nathan G.); Carpenter, R. W. (Robert W.)

2002-01-01T23:59:59.000Z

454

Special relativity as the limit of an Aristotelian universal friction theory under Reye's assumption  

E-Print Network [OSTI]

This work explores a classical mechanical theory under two further assumptions: (a) there is a universal dry friction force (Aristotelian mechanics), and (b) the variation of the mass of a body due to wear is proportional to the work done by the friction force on the body (Reye's hypothesis). It is shown that mass depends on velocity as in Special Relativity, and that the velocity is constant for a particular characteristic value. In the limit of vanishing friction the theory satisfies a relativity principle as bodies do not decelerate and, therefore, the absolute frame becomes unobservable. However, the limit theory is not Newtonian mechanics, with its Galilei group symmetry, but rather Special Relativity. This result suggests to regard Special Relativity as the limit of a theory presenting universal friction and exchange of mass-energy with a reservoir (vacuum). Thus, quite surprisingly, Special Relativity follows from the absolute space (ether) concept and could have been discovered following studies of Aristotelian mechanics and friction. We end the work confronting the full theory with observations. It predicts the Hubble law through tired light, and hence it is incompatible with supernova light curves unless both mechanisms of tired light (locally) and universe expansion (non-locally) are at work. It also nicely accounts for some challenging numerical coincidences involving phenomena under low acceleration.

E. Minguzzi

2014-11-28T23:59:59.000Z

455

Heat transfer system  

DOE Patents [OSTI]

A heat transfer system for a nuclear reactor. Heat transfer is accomplished within a sealed vapor chamber which is substantially evacuated prior to use. A heat transfer medium, which is liquid at the design operating temperatures, transfers heat from tubes interposed in the reactor primary loop to spaced tubes connected to a steam line for power generation purposes. Heat transfer is accomplished by a two-phase liquid-vapor-liquid process as used in heat pipes. Condensible gases are removed from the vapor chamber through a vertical extension in open communication with the chamber interior.

McGuire, Joseph C. (Richland, WA)

1982-01-01T23:59:59.000Z

456

Heat transfer system  

DOE Patents [OSTI]

A heat transfer system for a nuclear reactor is described. Heat transfer is accomplished within a sealed vapor chamber which is substantially evacuated prior to use. A heat transfer medium, which is liquid at the design operating temperatures, transfers heat from tubes interposed in the reactor primary loop to spaced tubes connected to a steam line for power generation purposes. Heat transfer is accomplished by a two-phase liquid-vapor-liquid process as used in heat pipes. Condensible gases are removed from the vapor chamber through a vertical extension in open communication with the chamber interior.

Not Available

1980-03-07T23:59:59.000Z

457

Automatic Methods for Predicting Functionally Important Residues  

E-Print Network [OSTI]

Pazos and Alfonso Valencia* Protein Design Group National Center for Biotechnology, Cantoblanco Madrid of protein families into subfamilies in the search for those positions that could have some functional families, testing the statistical meaning of the Tree-determinant residues predicted by three different

Pazos, Florencio

458

Residual Energy Spectrum of Solar Wind Turbulence  

E-Print Network [OSTI]

It has long been known that the energy in velocity and magnetic field fluctuations in the solar wind is not in equipartition. In this paper, we present an analysis of 5 years of Wind data at 1 AU to investigate the reason for this. The residual energy (difference between energy in velocity and magnetic field fluctuations) was calculated using both the standard magnetohydrodynamic (MHD) normalization for the magnetic field and a kinetic version, which includes temperature anisotropies and drifts between particle species. It was found that with the kinetic normalization, the fluctuations are closer to equipartition, with a mean normalized residual energy of sigma_r = -0.19 and mean Alfven ratio of r_A = 0.71. The spectrum of residual energy, in the kinetic normalization, was found to be steeper than both the velocity and magnetic field spectra, consistent with some recent MHD turbulence predictions and numerical simulations, having a spectral index close to -1.9. The local properties of residual energy and cros...

Chen, C H K; Salem, C S; Maruca, B A

2013-01-01T23:59:59.000Z

459

Chemical Stabilization of Hanford Tank Residual Waste  

SciTech Connect (OSTI)

Three different chemical treatment methods were tested for their ability to stabilize residual waste from Hanford tank C-202 for reducing contaminant release (Tc, Cr, and U in particular). The three treatment methods tested were lime addition [Ca(OH)2], an in-situ Ceramicrete waste form based on chemically bonded phosphate ceramics, and a ferrous iron/goethite treatment. These approaches rely on formation of insoluble forms of the contaminants of concern (lime addition and ceramicrete) and chemical reduction followed by co-precipitation (ferrous iron/goethite incorporation treatment). The results have demonstrated that release of the three most significant mobile contaminants of concern from tank residual wastes can be dramatically reduced after treatment compared to contact with simulated grout porewater without treatment. For uranium, all three treatments methods reduced the leachable uranium concentrations by well over three orders of magnitude. In the case of uranium and technetium, released concentrations were well below their respective MCLs for the wastes tested. For tank C-202 residual waste, chromium release concentrations were above the MCL but were considerably reduced relative to untreated tank waste. This innovative approach has the potential to revolutionize Hanford’s tank retrieval process, by allowing larger volumes of residual waste to be left in tanks while providing an acceptably low level of risk with respect to contaminant release that is protective of the environment and human health. Such an approach could enable DOE to realize significant cost savings through streamlined retrieval and closure operations.

Cantrell, Kirk J.; Um, Wooyong; Williams, Benjamin D.; Bowden, Mark E.; Gartman, Brandy N.; Lukens, Wayne W.; Buck, Edgar C.; Mausolf, Edward J.

2014-03-01T23:59:59.000Z

460

Municipal water-based heat pump heating and/or cooling systems: Findings and recommendations. Final report  

SciTech Connect (OSTI)

The purpose of the present work was to determine if existing heat pump systems based on municipal water systems meet existing water quality standards, to analyze water that has passed through a heat pump or heat exchanger to determine if corrosion products can be detected, to determine residual chlorine levels in municipal waters on the inlet as well as the outlet side of such installations, to analyses for bacterial contaminants and/or regrowth due to the presence of a heat pump or heat exchanger, to develop and suggest criteria for system design and construction, to provide recommendations and specifications for material and fluid selection, and to develop model rules and regulations for the installation, operation, and monitoring of new and existing systems. In addition, the Washington State University (WSU) has evaluated availability of computer models that would allow for water system mapping, water quality modeling and system operation.

Bloomquist, R.G. [Washington, State Univ., Pullman, WA (United States); Wegman, S. [South Dakota Utilities Commission (United States)

1998-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

Characterization of contaminants in oil shale residuals and the potential for their management to meet environmental quality standards. Final report  

SciTech Connect (OSTI)

Some general aspects of various oil shale processes developed for scale-up to commercial size modular units are described. The overall magnitude of an envisioned commercial shale oil operation and the magnitude of resulting potentially polluting residues in particular solid residues from retorting oil shale and associated operations and wastewater from retort streams and other sources are considered. The potential problems ensuing from self-oxidation of stockpiles of oil shale and from residual carbonaceous retorted oil shale disposed above ground and/or from in situ retorting operations are examined. Some methods for managing self-heating processes are suggested. The most plausible method of avoiding potential self-heating for retorted oil shale is to oxidize as much as possible of the organic carbon present by utilizing a process that will produce low carbon or carbon-free retorted oil shale residues. In the case of unretorted oil shale, the dimensions and shapes of the stockpiles should be designed such that heat build-up is eliminated or kept to a minimum.

Schmidt-Collerus, J.J.

1984-02-01T23:59:59.000Z

462

Consolidated Electric Cooperative- Heat Pump and Water Heating Rebates  

Broader source: Energy.gov [DOE]

Consolidated Electric Cooperative provides rebates to residential customers who install electric water heaters, dual-fuel heating system or geothermal heat pumps. A dual-fuel heating systems...

463

Temperature and water vapor pressure effects on the friction coefficient of hydrogenated diamondlike carbon films.  

SciTech Connect (OSTI)

Microtribological measurements of a hydrogenated diamondlike carbon film in controlled gaseous environments show that water vapor plays a significant role in the friction coefficient. These experiments reveal an initial high friction transient behavior that does not reoccur even after extended periods of exposure to low partial pressures of H{sub 2}O and O{sub 2}. Experiments varying both water vapor pressure and sample temperature show trends of a decreasing friction coefficient as a function of both the decreasing water vapor pressure and the increasing substrate temperature. Theses trends are examined with regard to first order gas-surface interactions. Model fits give activation energies on the order of 40 kJ/mol, which is consistent with water vapor desorption.

Dickrell, P. L.; Sawyer, W. G.; Eryilmaz, O. L.; Erdemir, A.; Energy Technology; Univ. of Florida

2009-07-01T23:59:59.000Z

464

Driven translocation of a polymer: role of pore friction and crowding  

E-Print Network [OSTI]

Force-driven translocation of a macromolecule through a nanopore is investigated by taking into account the monomer-pore friction as well as the "crowding" of monomers on the {\\it trans} - side of the membrane which counterbalance the driving force acting in the pore. The set of governing differential-algebraic equations for the translocation dynamics is derived and solved numerically. The analysis of this solution shows that the crowding of monomers on the trans side hardly affects the dynamics, but the monomer-pore friction can substantially slow down the translocation process. Moreover, the translocation exponent $\\alpha$ in the translocation time - vs. - chain length scaling law, $\\tau \\propto N^{\\alpha}$, becomes smaller when monomer-pore friction coefficient increases. This is most noticeable for relatively strong forces. Our findings may explain the variety of $\\alpha$ values which were found in experiments and computer simulations.

Johan L. A. Dubbeldam; V. G. Rostiashvili; T. A. Vilgis

2014-04-01T23:59:59.000Z

465

Identification of Friction Parameters from the Inverse Analysis of a Direct Extrusion Test  

SciTech Connect (OSTI)

This work proposes to use a special upsetting test and an optimal direct extrusion one performed to identify the constitutive equation of the material behavior and the friction coefficients directly from the load-stroke curves. The proposed friction test has the advantage to permit to take into account contact phenomena corresponding to new specimen surfaces created during a real bulk cold forming process. A lot of numerical simulations are made with the commercial software FORGE2 in order to study the influence of some design and process parameters. Different friction laws will be identified starting from the classical Coulomb and Tresca ones. All the parameter identifications are made using the Inverse Analysis principle.

Adinel, Gavrus; Thien, Pham Duc [LGCGM Laboratory, EA 3913, INSA de RENNES, UEB, CS70839, F-35708, Rennes-Cedex 7 (France); Henri, Francillette [SCR/CM, UMR 6226, INSA de RENNES, UEB, CS70839, F-35708, Rennes-Cedex 7 (France)

2011-01-17T23:59:59.000Z

466

Photovoltaic roof heat flux  

E-Print Network [OSTI]

designs (relatively) Photovoltaic Solar P a n e l AtmosphereCALIFORNIA, SAN DIEGO Photovoltaic Roof Heat Flux A ThesisABSTRACT OF T H E THESIS Photovoltaic Roof Heat Flux by

Samady, Mezhgan Frishta

2011-01-01T23:59:59.000Z

467

HEAT TRANSFER FLUIDS  

E-Print Network [OSTI]

The choice of heat transfer fluids has significant effects on the performance, cost, and reliability of solar thermal systems. In this chapter, we evaluate existing heat transfer fluids such as oils and molten salts based ...

Lenert, Andrej

2012-01-01T23:59:59.000Z

468

Abrasion resistant heat pipe  

DOE Patents [OSTI]

A specially constructed heat pipe for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.

Ernst, Donald M. (Leola, PA)

1984-10-23T23:59:59.000Z

469

MA HEAT Loan Overview  

Broader source: Energy.gov [DOE]

Presents information on the success of Massachusetts's HEAT loan offerings and how the financing tool is funded.

470

Abrasion resistant heat pipe  

DOE Patents [OSTI]

A specially constructed heat pipe is described for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.

Ernst, D.M.

1984-10-23T23:59:59.000Z

471

Solar heat receiver  

DOE Patents [OSTI]

A receiver is described for converting solar energy to heat a gas to temperatures from 700 to 900/sup 0/C. The receiver is formed to minimize impingement of radiation on the walls and to provide maximum heating at and near the entry of the gas exit. Also, the receiver is formed to provide controlled movement of the gas to be heated to minimize wall temperatures. The receiver is designed for use with gas containing fine heat absorbing particles, such as carbon particles.

Hunt, A.J.; Hansen, L.J.; Evans, D.B.

1982-09-29T23:59:59.000Z

472

Ammoniated salt heat pump  

SciTech Connect (OSTI)

A thermochemical heat pump/energy storage system using liquid ammoniate salts is described. The system, which can be used for space heating or cooling, provides energy storage for both functions. The bulk of the energy is stored as chemical energy and thus can be stored indefinitely. The system is well suited to use with a solar energy source or industrial waste heat.

Haas, W.R.; Jaeger, F.J.; Giordano, T.J.

1981-01-01T23:59:59.000Z

473

Heat Transfer Guest Editorial  

E-Print Network [OSTI]

Journal of Heat Transfer Guest Editorial We are indeed delighted in bringing out this special issue was showcased in diverse areas such as traditional heat and mass transfer, lab-on-chip, sensors, biomedical applica- tions, micromixers, fuel cells, and microdevices. Selected papers in the field of heat transfer

Kandlikar, Satish

474

Acoustic Heating Peter Ulmschneider  

E-Print Network [OSTI]

mechanisms. 1. The acoustic heating theory Only a few years after Edlen's (1941) discovery that the solar acoustic wave radiation- · b. field acoustic wave Figure 1. Panel a: Acoustic heating in late-type stars: effective temperature TeJ f, gravity g and mixing length parameter fr. Panel b: Acoustic heating in early

Ulmschneider, Peter

475

Liquid heat capacity lasers  

DOE Patents [OSTI]

The heat capacity laser concept is extended to systems in which the heat capacity lasing media is a liquid. The laser active liquid is circulated from a reservoir (where the bulk of the media and hence waste heat resides) through a channel so configured for both optical pumping of the media for gain and for light amplification from the resulting gain.

Comaskey, Brian J. (Walnut Creek, CA); Scheibner, Karl F. (Tracy, CA); Ault, Earl R. (Livermore, CA)

2007-05-01T23:59:59.000Z

476

Pioneering Heat Pump Project  

Broader source: Energy.gov [DOE]

Project objectives: To install and monitor an innovative WaterFurnace geothermal system that is technologically advanced and evolving; To generate hot water heating from a heat pump that uses non-ozone depleting refrigerant CO2. To demonstrate the energy efficiency of this system ground source heat pump system.

477

Studies of dynamic contact of ceramics and alloys for advanced heat engines. Final report  

SciTech Connect (OSTI)

Advanced materials and coatings for low heat rejection engines have been investigated for almost a decade. Much of the work has concentrated on the critical wear interface between the piston ring and cylinder liner. Simplified bench tests have identified families of coatings with high temperature wear performance that could meet or exceed that of conventional engine materials at today`s operating temperatures. More recently, engine manufacturers have begun to optimize material combinations and manufacturing processes so that the materials not only have promising friction and wear performance but are practical replacements for current materials from a materials and manufacturing cost standpoint. In this study, the advanced materials supplied by major diesel engine manufacturers were evaluated in an experimental apparatus that simulates many of the in-cylinder conditions of a low heat rejection diesel engine. Results include ring wear factors and average dynamic friction coefficients measured at intervals during the test. These results are compared with other advanced materials tested in the past as well as the baseline wear of current engines. Both fabricated specimens and sections of actual ring and cylinder liners were used in the testing. Observations and relative friction and wear performance of the individual materials are provided.

Gaydos, P.A.; Dufrane, K.F. [Battelle, Columbus, OH (United States)

1993-06-01T23:59:59.000Z

478

Friction and Wear Enhancement of Titanium Alloy Engine Components |  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensional Electrical Resistivity StructureDepartment of Energy 1 DOE

479

Friction of Steel Sliding Under Boundary Lubrication Regime in Commercial  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensional Electrical Resistivity StructureDepartment of EnergyGear Oils

480

Low-Friction Engineered Surfaces | Department of Energy  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensionalthe10IO1OP001Long-Termpaul_fini@cree.comVehicles6, 2015Engineered

Note: This page contains sample records for the topic "residual heat friction" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

Low-Friction Hard Coatings | Department of Energy  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensionalthe10IO1OP001Long-Termpaul_fini@cree.comVehicles6, 2015Engineered1

482

Low-Friction Hard Coatings | Department of Energy  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensionalthe10IO1OP001Long-Termpaul_fini@cree.comVehicles6,

483

Low-Friction Hard Coatings | Department of Energy  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensionalthe10IO1OP001Long-Termpaul_fini@cree.comVehicles6,09 DOE Hydrogen

484

Engine Friction Reduction Through Surface Finish and Coatings | Department  

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

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeat PumpRecord ofESPCof Energy 12, 2004Department ofEnforcingVehicleof Energy

485

Assessments of fluid friction factors for use in leak rate calculations  

SciTech Connect (OSTI)

Leak before Break procedures require estimates of leakage, and these in turn need fluid friction to be assessed. In this paper available data on flow rates through idealized and real crack geometries are reviewed in terms of a single friction factor k It is shown that for {lambda} < 1 flow rates can be bounded using correlations in terms of surface R{sub a} values. For {lambda} > 1 the database is less precise, but {lambda} {approx} 4 is an upper bound, hence in this region flow calculations can be assessed using 1 < {lambda} < 4.

Chivers, T.C. [Berkeley Technology Centre, Glos (United Kingdom)

1997-04-01T23:59:59.000Z

486

Casimir Friction in Terms of Moving Harmonic Oscillators: Equivalence Between Two Different Formulations  

E-Print Network [OSTI]

The Casimir friction problem can be dealt with in a simplified way by considering two harmonic oscillators moving with constant relative velocity. Recently we calculated the energy dissipation for such a case, [EPL {\\bf 91}, 60003 (2010); Europ. Phys. J. D {\\bf 61}, 335 (2011)]. A recent study of Barton [New J. Phys. {\\bf 12}, 113044 (2010)] seemingly leads to a different result for the dissipation. If such a discrepancy really were true, it would imply a delicate difficulty for the basic theory of Casimir friction. In the present note we show that the expressions for the dissipation are in fact physically equivalent, at T=0.

Johan S. Hřye; Iver Brevik

2011-01-06T23:59:59.000Z

487

Friction as a probe of surface properties of a polymer glass  

E-Print Network [OSTI]

We probe the temperature dependence of friction at the interface between a glassy poly(methylmethacrylate) lens and a flat substrate coated with a methyl-terminated self-assembled monolayer. The monolayer exhibits density defects which act as pinning sites for the polymer chains. We show that the shear response of such an interface supports the existence, at the surface of the glassy polymer, of a nanometer-thick layer of mobile chains. Friction can be ascribed to the interplay between viscouslike dissipation in this layer and depinning of chains adsorbed on the substrate. We further show that the pinning dynamics is controlled by \\beta rotational motions localized at the interface.

Lionel Bureau

2007-07-12T23:59:59.000Z

488

A corrosive resistant heat exchanger  

DOE Patents [OSTI]

A corrosive and erosive 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 pumped 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. 3 figs., 3 tabs.

Richlen, S.L.

1987-08-10T23:59:59.000Z

489

Development of a Robust and Cost-Effective Friction Stir Welding Process for Use in Advanced Military Vehicles  

E-Print Network [OSTI]

Development of a Robust and Cost-Effective Friction Stir Welding Process for Use in Advanced potential). Unfortu- nately, these alloys are not very amenable to conventional fusion-based welding technologies and in-order to obtain high-quality welds, solid-state joining technologies such as Friction stir

Grujicic, Mica

490

Friction and wear behavior of ultra-high molecular weight polyethylene as a function of polymer crystallinity  

E-Print Network [OSTI]

Friction and wear behavior of ultra-high molecular weight polyethylene as a function of polymer-grade ultra-high molecular weight polyethylene (UHMWPE) (GUR 1050 resin) were evaluated as a function replacements; Ultra-high molecular weight polyethylene (UHMWPE); Crystallinity; Friction; Wear 1. Introduction

Lin, Zhiqun

491

Influence of orographic and canopy conditions on friction velocities observed during frontal events using Doppler sodar observations  

SciTech Connect (OSTI)

Sodar friction velocities, obtained during frontal events traversing areas characterized by different orographic and canopy conditions (flat, bare ground, small hills and valleys with agricultural crops and trees, agricultural crops and forest on a flat ground, bare ground on the side of a mountain), are compared in order to identify the influence of topography on this parameter. For some case studies, sounding and sodar data are combined in order to provide a relation between the friction velocity and the low-level jet presence. For the cases analyzed in this paper, the following results are obtained: the frontal passage is associated with a decrease of the horizontal wind speed (about 50% in magnitude) in the surface layer, and an increase of the friction velocity before the frontal passage followed by a decrease just at the time of the frontal passage or with a little delay. Friction velocity is more intense in the cold side of the low-level jet and its maximum represents 2% of the low-level jet maximum magnitude. As it concerns the influence of the terrain conditions on friction velocity, mountain effects yield to more intense friction-velocity values and to a superposition of an oscillating behavior on the time variation of friction velocity, while forest effects induce a shift of the frontal signature on the time variation of friction velocity at higher height levels. 25 refs., 18 figs., 3 tabs.

Kotroni, V.; Amory-Mazaudier, C. (CRPE, Saint-Maur des Fosses (France))

1993-03-01T23:59:59.000Z

492

Department of Energy and Electrical Engineering Spring 2012 Heavy-Duty Diesel Engine Friction Reduction Testing and Analysis  

E-Print Network [OSTI]

PENNSTATE Department of Energy and Electrical Engineering Spring 2012 Heavy-Duty Diesel Engine and pumping frictional losses on Volvo-Mack's 11 liter Diesel Engine. Thermocouples and pressure transducers is to quantify friction losses on Volvo's current 11-liter engine model. Team members will remove hardware

Demirel, Melik C.

493

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

E-Print Network [OSTI]

. The logarithmic decrement as calculated by the time response is used to determine the active friction force. By affecting the vibrational mode shape (by the use of weights at each end), the free-free rotor can simulate the frictional characteristics of a rotor...

Parker, Jeffrey Scott

1997-01-01T23:59:59.000Z

494

The Rate-and State-Dependence of Sea Ice Friction Ben Lishman, Peter Sammonds, Daniel Feltham, and Alex Wilchinsky  

E-Print Network [OSTI]

for further work. 2. Experimental programme To produce a quantitative constitutive description of ice frictionPOAC09-66 The Rate- and State- Dependence of Sea Ice Friction Ben Lishman, Peter Sammonds, Daniel Feltham, and Alex Wilchinsky Rock and Ice Physics Laboratory, and Centre for Polar Observation

Feltham, Daniel

495

Chemical heat pump  

DOE Patents [OSTI]

A chemical heat pump system is disclosed for use in heating and cooling structures such as residences or commercial buildings. The system is particularly adapted to utilizing solar energy, but also increases the efficiency of other forms of thermal energy when solar energy is not available. When solar energy is not available for relatively short periods of time, the heat storage capacity of the chemical heat pump is utilized to heat the structure as during nighttime hours. The design also permits home heating from solar energy when the sun is shining. The entire system may be conveniently rooftop located. In order to facilitate installation on existing structures, the absorber and vaporizer portions of the system may each be designed as flat, thin wall, thin pan vessels which materially increase the surface area available for heat transfer. In addition, this thin, flat configuration of the absorber and its thin walled (and therefore relatively flexible) construction permits substantial expansion and contraction of the absorber material during vaporization and absorption without generating voids which would interfere with heat transfer. The heat pump part of the system heats or cools a house or other structure through a combination of evaporation and absorption or, conversely, condensation and desorption, in a pair of containers. A set of automatic controls change the system for operation during winter and summer months and for daytime and nighttime operation to satisfactorily heat and cool a house during an entire year. The absorber chamber is subjected to solar heating during regeneration cycles and is covered by one or more layers of glass or other transparent material. Daytime home air used for heating the home is passed at appropriate flow rates between the absorber container and the first transparent cover layer in heat transfer relationship in a manner that greatly reduce eddies and resultant heat loss from the absorbant surface to ambient atmosphere.

Greiner, Leonard (2750-C Segerstrom Ave., Santa Ana, CA 92704)

1980-01-01T23:59:59.000Z

496

Sodium Heat Engine Development Program  

SciTech Connect (OSTI)

The Sodium Heat Engine (SHE) is an efficient thermoelectric conversion device which directly generates electricity from a thermally regenerative electrochemical cell that relies on the unique conduction properties of {beta}{double prime}-alumina solid electrolyte (BASE). Laboratory models of a variety of SHE devices have demonstrated the feasibility and efficiency of the system, engineering development of large prototype devices has been slowed by a series of materials and fabrication problems. Failure of the electrolyte tubes has been a recurring problem and a number of possible causes have been postulated. To address these issues, a two-phase engineering development program was undertaken. This report summarizes the final results of the first phase of the program, which included extensive materials characterization activities, a study of applicable nondestructive evaluation methods, an investigation of possible stress states that would contribute to fracture, and certain operational issues associated with the electromagnetic pumps used in the SHE prototype. Mechanical and microstructural evaluation of commercially obtained BASE tubes revealed that they should be adequate for SHE applications and that sodium exposure produced no appreciable deleterious strength effects. Processing activities to produce a more uniform and smaller grain size for the BASE tubes were completed using isostatic pressing, extrusion, and slip casting. Green tubes were sintered by conventional and microwave plasma methods. Of particular interest is the residual stress state in the BASE tubes, and both analysis and nondestructive evaluation methods were employed to evaluate these stresses. X-ray and neutron diffraction experiments were performed to determine the bulk residual stresses in commercially fabricated BASE tubes; however, tube-to-tube variations and variations among the various methods employed did not allow formulation of a definitive definition of the as-fabricated stress state.

Singh, J.P.; Kupperman, D.S.; Majumdar, S.; Dorris, S.; Gopalsami, N.; Dieckman, S.L.; Jaross, R.A.; Johnson, D.L.; Gregar, J.S.; Poeppel, R.B.; Raptis, A.C.; Valentin, R.A.

1992-01-01T23:59:59.000Z

497

Development of statistical wet weather model to evaluate frictional properties at the pavement-tire interface on hot mix asphalt concrete  

E-Print Network [OSTI]

Skid resistance on wet pavements is influenced by friction at the tire-pavement interface as well as overall hot mix asphalt (HMA) performance. It is important to control aggregate, asphalt, and mix properties to achieve desirable frictional...

Bedi, Harpreet

2001-01-01T23:59:59.000Z

498

Absorption heat pump system  

DOE Patents [OSTI]

An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

Grossman, Gershon (Oak Ridge, TN); Perez-Blanco, Horacio (Knoxville, TN)

1984-01-01T23:59:59.000Z

499

Multiyear Program Plan: Reducing Friction and Wear in Heavy Vehicles  

SciTech Connect (OSTI)

As described in its multiyear program plan for 1998-2000, the Office of Heavy Vehicle Technologies (OHVT) envisions the development of a fuel-flexible, energy-efficient, near-zero-emissions, heavy-duty U.S. diesel engine technology devolving into all truck classes as a real and viable strategy for reducing energy requirements for commercial transport services and the rapidly growing multipurpose vehicle market (pickups, vans, and sport utility vehicles). Implementation of the OHVT program plan will have significant national benefits in energy savings, cleaner air, more jobs, and increased gross domestic product (GDP). Successful implementation will reduce the petroleum consumption of Class 1-8 trucks by 1.4 million barrels of oil per day by 2020 and over 1.8 million by 2030, amounting to a reduction in highway petroleum consumption of 13.2% and 18.6%, respectively. All types of regulated emissions will be reduced, that is, 20% drop in PM10 emissions (41,000 metric tons per year) by 203 0, 17% reduction in CO2 greenhouse gases (205 million metric tons per year), 7% reduction in NOx, 20% reduction in NMHC, and 30% reduction in CO. An increase of 15,000 jobs by 2020 is expected, as is an increase of $24 billion in GDP. The strategy of OHVT is to focus primarily on the diesel engine since it has numerous advantages. It has the highest efficiency of any engine today, 45% versus 30% for production gasoline engines; and it can be made more efficient at least to 55% and possibly up to 63%. It is the engine of choice for heavy vehicles (trucks), because it offers power, efficiency, durability, and reliability and is used extensively in rail, marine, and off-road applications. Its emission can be ultra-low to near zero, and the production infrastructure is already in place. The primary goals of OHVT are as follows: (1) Develop by 2002 the diesel-engine enabling technologies to support large-scale industry dieselization of light trucks, achieving a 35% fuel efficiency improvement over equivalent gasoline-fueled trucks. (2) Develop by 2004 the enabling technology for a Class 7-8 truck with a fuel efficiency of 10 mpg (at 65 mph) that will meet prevailing emission standards, using either diesel or a liquid alternative fuel. (3) Develop by 2006 diesel engines with fuel flexibility and a thermal efficiency of 55% with liquid alternative fuels, and a thermal efficiency of 55% with dedicated gaseous fuels. (4) Develop a methodology for analyzing and evaluating the operation of a heavy vehicle as an integrated system, considering such factors as engine efficiency; emissions; rolling resistance; aerodynamic drag; friction, wear, and lubrication effects; auxiliary power units; material substitutions for reducing weight; and other sources of parasitic energy losses. Overarching these considerations is the need to preserve system functionality, cost, competitiveness, reliability, durability, and safety.

R.R. Fessler; G.R. Fenske

1999-12-13T23:59:59.000Z

500

Heat pump apparatus  

DOE Patents [OSTI]

A heat pump apparatus including a compact arrangement of individual tubular reactors containing hydride-dehydride beds in opposite end sections, each pair of beds in each reactor being operable by sequential and coordinated treatment with a plurality of heat transfer fluids in a plurality of processing stages, and first and second valves located adjacent the reactor end sections with rotatable members having multiple ports and associated portions for separating the hydride beds at each of the end sections into groups and for simultaneously directing a plurality of heat transfer fluids to the different groups. As heat is being generated by a group of beds, others are being regenerated so that heat is continuously available for space heating. As each of the processing stages is completed for a hydride bed or group of beds, each valve member is rotated causing the heat transfer fluid for the heat processing stage to be directed to that bed or group of beds. Each of the end sections are arranged to form a closed perimeter and the valve member may be rotated repeatedly about the perimeter to provide a continuous operation. Both valves are driven by a common motor to provide a coordinated treatment of beds in the same reactors. The heat pump apparatus is particularly suitable for the utilization of thermal energy supplied by solar collectors and concentrators but may be used with any source of heat, including a source of low-grade heat.

Nelson, Paul A. (Wheaton, IL); Horowitz, Jeffrey S. (Woodridge, IL)

1983-01-01T23:59:59.000Z