WorldWideScience

Sample records for friction tester apparatus

  1. Design of Piston Ring Friction Tester Apparatus

    DEFF Research Database (Denmark)

    Klit, Peder

    2006-01-01

    the frictional behavior of a piston ring correctly is knowledge about the amount of lubricant present. For piston rings the external load may be established by measuring the pressure distribution, i.e. the pressure drop in the piston ring package. Speed and temperature may also be established. The amount...... and forces on piston rod. Since the frictional forces are small compared to the rest of the acting forces the main design idea is to fix the piston, while the cylinder liner moves. This approach makes it simple to measure the parameters mentioned above by putting the instrumentation in the piston....

  2. Multimodal Friction Ignition Tester

    Science.gov (United States)

    Davis, Eddie; Howard, Bill; Herald, Stephen

    2009-01-01

    The multimodal friction ignition tester (MFIT) is a testbed for experiments on the thermal and mechanical effects of friction on material specimens in pressurized, oxygen-rich atmospheres. In simplest terms, a test involves recording sensory data while rubbing two specimens against each other at a controlled normal force, with either a random stroke or a sinusoidal stroke having controlled amplitude and frequency. The term multimodal in the full name of the apparatus refers to a capability for imposing any combination of widely ranging values of the atmospheric pressure, atmospheric oxygen content, stroke length, stroke frequency, and normal force. The MFIT was designed especially for studying the tendency toward heating and combustion of nonmetallic composite materials and the fretting of metals subjected to dynamic (vibrational) friction forces in the presence of liquid oxygen or pressurized gaseous oxygen test conditions approximating conditions expected to be encountered in proposed composite material oxygen tanks aboard aircraft and spacecraft in flight. The MFIT includes a stainless-steel pressure vessel capable of retaining the required test atmosphere. Mounted atop the vessel is a pneumatic cylinder containing a piston for exerting the specified normal force between the two specimens. Through a shaft seal, the piston shaft extends downward into the vessel. One of the specimens is mounted on a block, denoted the pressure block, at the lower end of the piston shaft. This specimen is pressed down against the other specimen, which is mounted in a recess in another block, denoted the slip block, that can be moved horizontally but not vertically. The slip block is driven in reciprocating horizontal motion by an electrodynamic vibration exciter outside the pressure vessel. The armature of the electrodynamic exciter is connected to the slip block via a horizontal shaft that extends into the pressure vessel via a second shaft seal. The reciprocating horizontal

  3. Trial manufacture of rotary friction tester and frictional force measurement of metals

    CERN Document Server

    Abe, T; Kanari, M; Tanzawa, S

    2002-01-01

    In the plasma confinement type fusion reactor, in-vessel structures such as a blanket module slide at the joints each other when plasma disruption occurs, and then frictional heat is generated there. Therefore, for the selection of material and the use as the design data, it is important to understand the frictional characteristics of metals and ceramic films in the vacuum. In the present study, we have manufactured a prototype of rotary friction tester and examined the performances of the tester. The frictional characteristics of metals in the room air was measured using the friction tester, and the results obtained are as follows. A drifting friction force for a constant time and a friction force during the idling were 98 mN and 225 mN, respectively. These values were sufficiently small as compared to pressing load (9.8 - 57.8 N) used in the friction test. In a friction force measurement of stainless steel, dynamic friction force obeyed Amontons' law which indicated that dynamic friction force is not depend...

  4. Frictorq, fabric friction tester : a comparartive study eith kes

    OpenAIRE

    2009-01-01

    Coeficiente of friction is one of the factors involved in the so-called parameter fabric hand its importance justifies the number of contributions give in the past to this problem. more recently, a new laboratory instrument was proposed by the authors for the assessment of tis property. A comparative study with another widely respected instruments, the Kes-friction, is the main purpose of this research.

  5. A portable wheel tester for tyre-road friction and rolling resistance determination

    Science.gov (United States)

    Pytka, J.; Budzyński, P.; Tarkowski, P.; Piaskowski, M.

    2016-09-01

    The paper describes theory of operation, design and construction as well as results from primarily experiments with a portable wheel tester that has been developed by the authors as a device for on-site determination of tyre-road braking/driving friction and rolling resistance. The paper includes schematics, drawings, descriptions as well as graphical results form early tests with the presented device. It is expected that the tester can be useful in road accident reconstruction applications as well as in vehicle dynamics research.

  6. Apparatus Measures Friction In Vacuum Or Pressurized Gas

    Science.gov (United States)

    Trevathan, Joseph R.

    1996-01-01

    Friction-testing apparatus in small test chamber contains special atmosphere, which could include vacuum or pressurized gas. Provides readings indicative of friction between pin specimen and plate specimen sliding under pin in reciprocating linear motion. Pin and plate specimens made of same or different material.

  7. Portable Tester Friction (PFT). Mesures du coefficient de frottement dynamique de revêtements de sol

    OpenAIRE

    Marchal, P.; Jacques, M.

    2014-01-01

    Le Portable Tester Friction (PFT) est un appareil destiné à mesurer le coefficient de frottement dynamique d’un revêtement de sol en laboratoire et sur site. Ce document décrit le protocole de mesure avec le PFT et les résultats de mesures effectuées sur un panel de quinze revêtements de sol de caractéristiques différentes (matériaux, états de surface) réalisées en présence de deux polluants (huile et solution d’eau). Le PFT présente une très bonne sensibilité et une très bonne répétabilité. ...

  8. Improvement of Swing Friction Sensitivity Tester%摆式摩擦感度仪的改进

    Institute of Scientific and Technical Information of China (English)

    徐莉; 杜云峰; 黄茶香; 柳继昌

    2011-01-01

    对含能材料测定摩擦感度的意义、摆式摩擦仪感度仪工作原理做了详细介绍,对20世纪40年代原苏联K-44-Ⅲ型摆式摩擦仪的结构、加压方式、检定方法等进行了改进.改进后的MGY-1型摩擦感度仪在结构上用限位槽取代分离钩,用电动油泵取代手动油泵加压.对改进后的MGY-1型摩擦感度仪做了对比试验:不同表压和摆角条件下滑移距离测试,手动油泵加压与电动油泵加压滑移距离测试,列举了几种火工药剂摩擦感度的测试数据.改进后的MGY-1型摩擦感度仪提高了工作效率和测试精度,得到了广泛应用和推广.%In this paper, we introduce the significance of testing friction sensitivity for energetic materials, describe the working principle of swing friction sensitivity tester in detail, and improve K-44-Ⅲ type swing friction tester of Soviet by the structure, compression method and verification method. The improved type-MGY-1 friction sensitivity tester substitutes the disengaging hook in structure with the spacing trough, and substitutes the manual oil pump with the motor driven oil pump. We made the contrast test with the improved tester:sliding distance test in different gauge pressure and different swing angle conditions,and sliding distance test in manual oil pump and motor driven oil pump conditions. The test data of some explosive friction sensitivity are listed,and the results show that the test efficiency and accuracy of the improved tester are improved, and the instrument has obtained widely application and promotion.

  9. Apparatus and method to reduce wear and friction between CMC-to-metal attachment and interface

    Energy Technology Data Exchange (ETDEWEB)

    Cairo, Ronald Ralph; Parolini, Jason Robert; Delvaux, John McConnell

    2016-11-22

    An apparatus to reduce wear and friction between CMC-to-metal attachment and interface, including a metal layer configured for insertion between a surface interface between a CMC component and a metal component. The surface interface of the metal layer is compliant relative to asperities of the surface interface of the CMC component. A coefficient of friction between the surface interface of the CMC component and the metal component is about 1.0 or less at an operating temperature between about 300.degree. C. to about 325.degree. C. and a limiting temperature of the metal component.

  10. Proposed apparatus for measuring internal friction in rocks at high temperatures and pressures: a design analysis

    Energy Technology Data Exchange (ETDEWEB)

    Bonner, B.P.

    1977-10-03

    An apparatus is described that measures internal friction in rocks at high temperatures (approximately 800/sup 0/C) and pressures (approximately 1.0 GPa). Steady oscillations (approximately 1.0 Hz) are induced in a jacketed sample while coaxial capacitive transducers monitor the resulting radial strain. Sample strains are continuously compared to the deformation of a low-loss standard, which acts as a stress transducer. The stress state produced is uniaxial stress. We use the theory of viscoelasticity to partition the loss into components depending on pure shear and dilatation. The theoretical results emphasize the importance of ultimately measuring each loss independently.

  11. Explosives tester

    Science.gov (United States)

    Haas, Jeffrey S [San Ramon, CA; Howard, Douglas E [Livermore, CA; Eckels, Joel D [Livermore, CA; Nunes, Peter J [Danville, CA

    2011-01-11

    An explosives tester that can be used anywhere as a screening tool by non-technical personnel to determine whether a surface contains explosives. First and second explosives detecting reagent holders and dispensers are provided. A heater is provided for receiving the first and second explosives detecting reagent holders and dispensers.

  12. Investigation of scale effects and directionality dependence on friction and adhesion of human hair using AFM and macroscale friction test apparatus.

    Science.gov (United States)

    LaTorre, Carmen; Bhushan, Bharat

    2006-01-01

    Macroscale testing of human hair tribological properties has been widely used to aid in the development of better shampoos and conditioners. Recently, literature has focused on using the atomic force microscope (AFM) to study surface roughness, coefficient of friction, adhesive force, and wear (tribological properties) on the nanoscale in order to increase understanding about how shampoos and conditioners interact with the hair cuticle. Since there are both similarities and differences when comparing the tribological trends at both scales, it is thus recognized that scale effects are an important aspect of studying the tribology of hair. However, no microscale tribological data for hair exists in literature. This is unfortunate because many interactions between hair-skin, hair-comb, and hair-hair contact takes place at microasperities ranging from a few mum to hundreds of mum. Thus, to bridge the gap between the macro- and nanoscale data, as well as to gain a full understanding of the mechanisms behind the trends, it is now worthwhile to look at hair tribology on the microscale. Presented in this paper are coefficient of friction and adhesive force data on various scales for virgin and chemically damaged hair, both with and without conditioner treatment. Macroscale coefficient of friction was determined using a traditional friction test apparatus. Microscale and nanoscale tribological characterization was performed with AFM tips of various radii. The nano-, micro-, and macroscale trends are compared and the mechanisms behind the scale effects are discussed. Since the coefficient of friction changes drastically (on any scale) depending on whether the direction of motion is along or against the cuticle scales, the directionality dependence and responsible mechanisms are discussed.

  13. Investigation of scale effects and directionality dependence on friction and adhesion of human hair using AFM and macroscale friction test apparatus

    Energy Technology Data Exchange (ETDEWEB)

    LaTorre, Carmen [Nanotribology Laboratory for Information Storage and MEMS/NEMS (NLIM), Ohio State University, Suite 255, 650 Ackerman Road, Columbus, OH 43202 (United States); Bhushan, Bharat [Nanotribology Laboratory for Information Storage and MEMS/NEMS (NLIM), Ohio State University, Suite 255, 650 Ackerman Road, Columbus, OH 43202 (United States)]. E-mail: bhushan.2@osu.edu

    2006-06-15

    Macroscale testing of human hair tribological properties has been widely used to aid in the development of better shampoos and conditioners. Recently, literature has focused on using the atomic force microscope (AFM) to study surface roughness, coefficient of friction, adhesive force, and wear (tribological properties) on the nanoscale in order to increase understanding about how shampoos and conditioners interact with the hair cuticle. Since there are both similarities and differences when comparing the tribological trends at both scales, it is thus recognized that scale effects are an important aspect of studying the tribology of hair. However, no microscale tribological data for hair exists in literature. This is unfortunate because many interactions between hair-skin, hair-comb, and hair-hair contact takes place at microasperities ranging from a few {mu}m to hundreds of {mu}m. Thus, to bridge the gap between the macro- and nanoscale data, as well as to gain a full understanding of the mechanisms behind the trends, it is now worthwhile to look at hair tribology on the microscale. Presented in this paper are coefficient of friction and adhesive force data on various scales for virgin and chemically damaged hair, both with and without conditioner treatment. Macroscale coefficient of friction was determined using a traditional friction test apparatus. Microscale and nanoscale tribological characterization was performed with AFM tips of various radii. The nano-, micro-, and macroscale trends are compared and the mechanisms behind the scale effects are discussed. Since the coefficient of friction changes drastically (on any scale) depending on whether the direction of motion is along or against the cuticle scales, the directionality dependence and responsible mechanisms are discussed.

  14. Laboratory experiment for the study of friction forces using rotating apparatus

    Science.gov (United States)

    Kladivová, Mária; Kovaľaková, Mária; Gibová, Zuzana; Fričová, Oľga; Hutníková, Mária; Kecer, Ján

    2016-11-01

    The standard experimental set-up enabling observation of rotational motion of a bar around its centre of mass, which is set into motion due to the external torque generated by the small weight, was extended with an optical gate and position sensor and connected to a computer with software, which made it possible to display measured values of bar half-rotations during accelerated and decelerated motion as well as to process the data immediately. The detailed analysis of experimental data obtained for decelerated rotational motion due to frictional torque only (without small weight) showed that, besides the constant term due to dry friction at an axle, the expression for friction forces in the system has to include terms depending on the first and/or second power of angular speed, which is evidence that viscous forces influence the motion of a bar. The frictional torque due to viscous forces can be evaluated as the difference between the effective frictional torque acting on the system and the frictional torque due to dry friction at an axle. The data obtained in the experiment in which the bar performed damped oscillatory motion provided the values of effective frictional torque and the moment of inertia of rotating bodies. The frictional torque due to dry friction can be obtained as a minimum torque (calculated using minimum mass of weight) needed to start rotational motion. The last two proposed experiments can be included in undergraduate laboratory practicals.

  15. Dynamic Hardness Tester and Cure Meter

    Science.gov (United States)

    Madigosky, Walter M.; Fiorito, Ralph B.

    1993-01-01

    The Shore hardness tester is used extensively throughout industry to determine the static modulus of materials. The new apparatus described here extends the capability of an indentor-type tester into the dynamic regime, and provides a measurement of the dynamic shear or Young's modulus and loss factor as a function of frequency. The instrument, model and data of typical rubber samples are given and compared to other dynamic measurements.

  16. Hardness Tester for Polyur

    Science.gov (United States)

    Hauser, D. L.; Buras, D. F.; Corbin, J. M.

    1987-01-01

    Rubber-hardness tester modified for use on rigid polyurethane foam. Provides objective basis for evaluation of improvements in foam manufacturing and inspection. Typical acceptance criterion requires minimum hardness reading of 80 on modified tester. With adequate correlation tests, modified tester used to measure indirectly tensile and compressive strengths of foam.

  17. UW VLSI chip tester

    Science.gov (United States)

    McKenzie, Neil

    1989-12-01

    We present a design for a low-cost, functional VLSI chip tester. It is based on the Apple MacIntosh II personal computer. It tests chips that have up to 128 pins. All pin drivers of the tester are bidirectional; each pin is programmed independently as an input or an output. The tester can test both static and dynamic chips. Rudimentary speed testing is provided. Chips are tested by executing C programs written by the user. A software library is provided for program development. Tests run under both the Mac Operating System and A/UX. The design is implemented using Xilinx Logic Cell Arrays. Price/performance tradeoffs are discussed.

  18. Explosives tester with heater

    Science.gov (United States)

    Del Eckels, Joel [Livermore, CA; Nunes, Peter J [Danville, CA; Simpson, Randall L [Livermore, CA; Whipple, Richard E [Livermore, CA; Carter, J Chance [Livermore, CA; Reynolds, John G [San Ramon, CA

    2010-08-10

    An inspection tester system for testing for explosives. The tester includes a body and a swab unit adapted to be removeably connected to the body. At least one reagent holder and dispenser is operatively connected to the body. The reagent holder and dispenser contains an explosives detecting reagent and is positioned to deliver the explosives detecting reagent to the swab unit. A heater is operatively connected to the body and the swab unit is adapted to be operatively connected to the heater.

  19. Bipolar Transistor Tester for Physics Lab

    CERN Document Server

    Baddi, Raju

    2012-01-01

    A very simple low cost bipolar transistor tester for physics lab is given. The proposed circuit not only indicates the type of transistor(NPN/PNP) but also indicates the terminals(emitter, base and collector) using simple dual colored(Red/Green) LEDs. Color diagrams of testing procedure have been given for easy following. This article describes the construction of this apparatus in all detail with schematic circuit diagram, circuit layout and constructional illustration.

  20. Common tester platform concept.

    Energy Technology Data Exchange (ETDEWEB)

    Hurst, Michael James

    2008-05-01

    This report summarizes the results of a case study on the doctrine of a common tester platform, a concept of a standardized platform that can be applicable across the broad spectrum of testing requirements throughout the various stages of a weapons program, as well as across the various weapons programs. The common tester concept strives to define an affordable, next-generation design that will meet testing requirements with the flexibility to grow and expand; supporting the initial development stages of a weapons program through to the final production and surveillance stages. This report discusses a concept investing key leveraging technologies and operational concepts combined with prototype tester-development experiences and practical lessons learned gleaned from past weapons programs.

  1. Cable Tester Box

    Science.gov (United States)

    Lee, Jason H.

    2011-01-01

    Cables are very important electrical devices that carry power and signals across multiple instruments. Any fault in a cable can easily result in a catastrophic outcome. Therefore, verifying that all cables are built to spec is a very important part of Electrical Integration Procedures. Currently, there are two methods used in lab for verifying cable connectivity. (1) Using a Break-Out Box and an ohmmeter this method is time-consuming but effective for custom cables and (2) Commercial Automated Cable Tester Boxes this method is fast, but to test custom cables often requires pre-programmed configuration files, and cables used on spacecraft are often uniquely designed for specific purposes. The idea is to develop a semi-automatic continuity tester that reduces human effort in cable testing, speeds up the electrical integration process, and ensures system safety. The JPL-Cable Tester Box is developed to check every single possible electrical connection in a cable in parallel. This system indicates connectivity through LED (light emitting diode) circuits. Users can choose to test any pin/shell (test node) with a single push of a button, and any other nodes that are shorted to the test node, even if they are in the same connector, will light up with the test node. The JPL-Cable Tester Boxes offers the following advantages: 1. Easy to use: The architecture is simple enough that it only takes 5 minutes for anyone to learn how operate the Cable Tester Box. No pre-programming and calibration are required, since this box only checks continuity. 2. Fast: The cable tester box checks all the possible electrical connections in parallel at a push of a button. If a cable normally takes half an hour to test, using the Cable Tester Box will improve the speed to as little as 60 seconds to complete. 3. Versatile: Multiple cable tester boxes can be used together. As long as all the boxes share the same electrical potential, any number of connectors can be tested together.

  2. Four Sided Seal Tester

    Science.gov (United States)

    2009-07-01

    The Center for Advanced Food Technology School of Enviromental and Biological Sciences New Brunswick, NJ 08903 FTR 216 Defense Logistics Agency...specification for four sided seal tester as function of confinement plate distance” The following modifications were issued :  Jul 18, 2007 0013/01

  3. Transformer and Meter Tester

    Science.gov (United States)

    Stoms, R. M.

    1984-01-01

    Numerically-controlled 5-axis machine tool uses transformer and meter to determine and indicate whether tool is in home position, but lacks built-in test mode to check them. Tester makes possible test, and repair of components at machine rather then replace them when operation seems suspect.

  4. Inspection tester for explosives

    Science.gov (United States)

    Haas, Jeffrey S.; Simpson, Randall L.; Satcher, Joe H.

    2007-11-13

    An inspection tester that can be used anywhere as a primary screening tool by non-technical personnel to determine whether a surface contains explosives. It includes a body with a sample pad. First and second explosives detecting reagent holders and dispensers are operatively connected to the body and the sample pad. The first and second explosives detecting reagent holders and dispensers are positioned to deliver the explosives detecting reagents to the sample pad. A is heater operatively connected to the sample pad.

  5. Research and development of dry pneumatic friction clutch-brake tester%组合式气动干式摩擦离合制动器试验台研制

    Institute of Scientific and Technical Information of China (English)

    王骏; 吴迅; 蒋兆军; 韦国上

    2015-01-01

    This article describes the data gain from the performance of the versatile clutch-brake performance tester,which provides not only a performance testing platform for optimization design of clutch-brake,but also the experimental basis for the formulation of industry standards in the relevant product data.The tester is an integrated system including clutch torque testing,brake torque testing,sensitivity testing,temperature testing and balance testing.Detecting and collecting data by its sensors,the tester can display and compare the results for research after centralized computer processing,with the characteristics of high integration and versatility.%为了研究离合制动器的性能指标、给离合制动器的优化设计提供性能测试平台,同时也为该产品的行业标准制订中的相关数据提供试验依据,研制了这款多功能离合制动器综合性能试验台。该试验台的机械平台集中了离合、制动扭矩检测、灵敏度检测、温升检测、平衡检测等性能测试模块,通过传感器进行检测并采集数据,经计算机集中处理后,显示结果以供研究和比较。该试验台具有集成度高、通用性强等特点。

  6. Single wheel testers, single track testers, and instrumented tractors

    Science.gov (United States)

    Single wheel testers and single track testers are used for determining tractive performance characteristics of tires and tracks. Instrumented tractors are useful in determining the tractive performance of tractors. These machines are also used for determining soil-tire and soil-track interactions,...

  7. Design of High-speed Wear Lifetime Tester of the Instrument Ball Bearings

    Science.gov (United States)

    Liu, C. H.; Gu, J. M.; Sun, Y.; Chen, X. Y.

    2006-10-01

    respectively as the accessorial parameters to assess the real quality of the bearings. Experimental results show that this tester has the capable of presetting load, rotating speed and temperature; monitoring the raise of the temperature and vibration of each bearing, frictional torque and the power variation of the apparatus automatically, these parameters can also be saved as a datum file into the computer at the same time. The developed tester can be used to carry on wear lifetime test, it is suitable for various kinds of instrument ball bearings with different structure and dimension which have been applied for different working conditions, it realized the self-service, intelligent management of the test, and provided a basis for the implement of the lifetime and reliability test to the instrument ball bearings.

  8. Hydrogen fracture toughness tester completion

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, Michael J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-09-30

    The Hydrogen Fracture Toughness Tester (HFTT) is a mechanical testing machine designed for conducting fracture mechanics tests on materials in high-pressure hydrogen gas. The tester is needed for evaluating the effects of hydrogen on the cracking properties of tritium reservoir materials. It consists of an Instron Model 8862 Electromechanical Test Frame; an Autoclave Engineering Pressure Vessel, an Electric Potential Drop Crack Length Measurement System, associated computer control and data acquisition systems, and a high-pressure hydrogen gas manifold and handling system.

  9. Penetration Tester's Open Source Toolkit

    CERN Document Server

    Faircloth, Jeremy

    2011-01-01

    Great commercial penetration testing tools can be very expensive and sometimes hard to use or of questionable accuracy. This book helps solve both of these problems. The open source, no-cost penetration testing tools presented do a great job and can be modified by the user for each situation. Many tools, even ones that cost thousands of dollars, do not come with any type of instruction on how and in which situations the penetration tester can best use them. Penetration Tester's Open Source Toolkit, Third Edition, expands upon existing instructions so that a professional can get the most accura

  10. Blood Vessel Tension Tester

    Science.gov (United States)

    1978-01-01

    In the photo, a medical researcher is using a specially designed laboratory apparatus for measuring blood vessel tension. It was designed by Langley Research Center as a service to researchers of Norfolk General Hospital and Eastern Virginia Medical School, Norfolk, Virginia. The investigators are studying how vascular smooth muscle-muscle in the walls of blood vessels-reacts to various stimulants, such as coffee, tea, alcohol or drugs. They sought help from Langley Research Center in devising a method of measuring the tension in blood vessel segments subjected to various stimuli. The task was complicated by the extremely small size of the specimens to be tested, blood vessel "loops" resembling small rubber bands, some only half a millimeter in diameter. Langley's Instrumentation Development Section responded with a miniaturized system whose key components are a "micropositioner" for stretching a length of blood vessel and a strain gage for measuring the smooth muscle tension developed. The micropositioner is a two-pronged holder. The loop of Mood vessel is hooked over the prongs and it is stretched by increasing the distance between the prongs in minute increments, fractions of a millimeter. At each increase, the tension developed is carefully measured. In some experiments, the holder and specimen are lowered into the test tubes shown, which contain a saline solution simulating body fluid; the effect of the compound on developed tension is then measured. The device has functioned well and the investigators say it has saved several months research time.

  11. Microcontroller based Integrated Circuit Tester

    Directory of Open Access Journals (Sweden)

    Yousif Taha Yousif Elamin

    2015-02-01

    Full Text Available The digital integrated circuit (IC tester is implemented by using the ATmega32 microcontroller . The microcontroller processes the inputs and outputs and displays the results on a Liquid Crystal Display (LCD. The basic function of the digital IC tester is to test a digital IC for correct logical functioning as described in the truth table and/or function table. The designed model can test digital ICs having 14 pins. Since it is programmable, any number of ICs can be tested . This model applies the necessary signals to the inputs of the IC, monitoring the outputs at each stage and comparing them with the outputs in the truth table. Any discrepancy in the functioning of the IC results in a fail indication, displays the faulty and good gates on the LCD. The testing procedure is accomplished with the help of keypad keys present on the main board design. The test has been accomplished with most commonly used digital IC's, mainly belonging to the 74 series. Digital IC tester tests three samples of IC's ( NAND, NOT, NOR. The design is flexible . We can add extra IC bases and subroutines to test any other IC in the 74 series.

  12. Enhanced Master Controller Unit Tester

    Science.gov (United States)

    Benson, Patricia; Johnson, Yvette; Johnson, Brian; Williams, Philip; Burton, Geoffrey; McCoy, Anthony

    2007-01-01

    The Enhanced Master Controller Unit Tester (EMUT) software is a tool for development and testing of software for a master controller (MC) flight computer. The primary function of the EMUT software is to simulate interfaces between the MC computer and external analog and digital circuitry (including other computers) in a rack of equipment to be used in scientific experiments. The simulations span the range of nominal, off-nominal, and erroneous operational conditions, enabling the testing of MC software before all the equipment becomes available.

  13. The ATLAS RunTimeTester

    CERN Document Server

    The ATLAS collaboration

    2016-01-01

    The ATLAS RunTimeTester is a job based software test system. The RunTimeTester runs jobs, and optional tests on the job outputs. Job and test results are reported via a web site. The system currently runs $\\approx$ 8000 jobs daily, and the web site receives $\\approx$ 25K hits a week. This note provides an overview of the system.

  14. Flying Probe Tester: Architecture, Principle and Implementation

    Institute of Scientific and Technical Information of China (English)

    Fu,Xu; Fang,Kangling; Chen,Guoqing

    2005-01-01

    This paper introduces the flying probe tester, which is a testing device for PCB. The architecture and principle of flying probe tester are firstly introduced. Then the implementation of hardware and software is illuminated briefly. Finally, the optimizing method for the probe's moving path is researched based on the traveling salesman problem.

  15. Environmental tester development. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Tressler, R.E.

    1998-08-01

    The primary objective is to further develop the environmental tensometer toward commercialization by making key technical refinements, improving the controlling and data-logging software, and testing the system in a potential customer`s laboratory. Progress has been made in Tasks 1 (completed), Task 2 (one half completed), Task 4 (one half completed) of the original work plan. In this report a detailed description of the work completed on the second prototype is explained in detail. A second prototype of the Environmental Tester, a device capable of tensile tests of fibers in controlled environments and at high temperatures, has been designed and is currently being fabricated. The first prototype includes six integrated systems; the testing system, the furnace system, the vacuum system, the mass flow control system, and the computer data acquisition and control (CDAC) system.

  16. Fast Electronic Solar Cell Tester

    Science.gov (United States)

    Lathrop, J. W.; Saylor, C. R.

    1983-01-01

    Microcomputer controlled system gather current and voltage data. System consists of light source, microcomputer, programable dc power supply, analog/ digital interface, and data storage display equipment. Applies series of test loads to cell via programable dc power supply to obtain I/V characteristic curve and key cell-peformance parameter. Apparatus and programming technique are applicable to devices such as batteries and sensors.

  17. Design and development of seal components fatigue tester

    Directory of Open Access Journals (Sweden)

    P. Czop

    2008-09-01

    Full Text Available Purpose: The aim of the paper is research and development concerning a fatigue tester of shock absorber seal systems.Design/methodology/approach: Analytical approach has been applied to get an understanding of a heat exchange process. The mathematical model has been formulated and validated based on the available measurements. Numerical simulation has been carried out to illustrate a heat exchange process performance.Findings: It is possible to control a seal temperature and mechanical friction related to the rod movement into the seal at the specified velocity. The model accuracy is sufficient to perform sensitivity analysis and optimize the design.Research limitations/implications: The components of a fatigue tester have to withstand the significant temperature differences in the range 30; +140˚C, e.g. hydraulic hoses, fittings, and pumps.Practical implications: We combine the analytical and experimental approach to provide customized and reliable engineering solution in the area of damper component seal development. A typical seal has a lip-like design protecting the moving parts against the leakage. It can be tested in a shock absorber or externally with use of a customized test rigs. Seal tests inside a shock absorber have numerous disadvantages. A shock absorber temperature rises during longer tests and cooling phase is required. This dramatically increases tests duration performed with the use of an expensive general-purpose hydraulic testing machinery. A compressed air or water jacket is used to accelerate the cooling process. Nevertheless, there are limitations related to the physics behind the cooling process. A seal component fatigue tester allows to perform the seal component tests out of the shock absorber.Originality/value: A new testing method provides possibility to quantify the main contributors of seal usage.

  18. Friction and Wear Performance of Boron Doped, Undoped Microcrystalline and Fine Grained Composite Diamond Films

    Institute of Scientific and Technical Information of China (English)

    WANG Xinchang; WANG Liang; SHEN Bin; SUN Fanghong

    2015-01-01

    Chemical vapor deposition (CVD) diamond films have attracted more attentions due to their excellent mechanical properties. Whereas as-fabricated traditional diamond films in the previous studies don’t have enough adhesion or surface smoothness, which seriously impact their friction and wear performance, and thus limit their applications under extremely harsh conditions. A boron doped, undoped microcrystalline and fine grained composite diamond (BD-UM-FGCD) film is fabricated by a three-step method adopting hot filament CVD (HFCVD) method in the present study, presenting outstanding comprehensive performance, including the good adhesion between the substrate and the underlying boron doped diamond (BDD) layer, the extremely high hardness of the middle undoped microcrystalline diamond (UMCD) layer, as well as the low surface roughness and favorable polished convenience of the surface fine grained diamond (FGD) layer. The friction and wear behavior of this composite film sliding against low-carbon steel and silicon nitride balls are studied on a ball-on-plate rotational friction tester. Besides, its wear rate is further evaluated under a severer condition using an inner-hole polishing apparatus, with low-carbon steel wire as the counterpart. The test results show that the BD-UM-FGCD film performs very small friction coefficient and great friction behavior owing to its high surface smoothness, and meanwhile it also has excellent wear resistance because of the relatively high hardness of the surface FGD film and the extremely high hardness of the middle UMCD film. Moreover, under the industrial conditions for producing low-carbon steel wires, this composite film can sufficiently prolong the working lifetime of the drawing dies and improve their application effects. This research develops a novel composite diamond films owning great comprehensive properties, which have great potentials as protecting coatings on working surfaces of the wear-resistant and anti-frictional

  19. Friction and wear performance of boron doped, undoped microcrystalline and fine grained composite diamond films

    Science.gov (United States)

    Wang, Xinchang; Wang, Liang; Shen, Bin; Sun, Fanghong

    2015-01-01

    Chemical vapor deposition (CVD) diamond films have attracted more attentions due to their excellent mechanical properties. Whereas as-fabricated traditional diamond films in the previous studies don't have enough adhesion or surface smoothness, which seriously impact their friction and wear performance, and thus limit their applications under extremely harsh conditions. A boron doped, undoped microcrystalline and fine grained composite diamond (BD-UM-FGCD) film is fabricated by a three-step method adopting hot filament CVD (HFCVD) method in the present study, presenting outstanding comprehensive performance, including the good adhesion between the substrate and the underlying boron doped diamond (BDD) layer, the extremely high hardness of the middle undoped microcrystalline diamond (UMCD) layer, as well as the low surface roughness and favorable polished convenience of the surface fine grained diamond (FGD) layer. The friction and wear behavior of this composite film sliding against low-carbon steel and silicon nitride balls are studied on a ball-on-plate rotational friction tester. Besides, its wear rate is further evaluated under a severer condition using an inner-hole polishing apparatus, with low-carbon steel wire as the counterpart. The test results show that the BD-UM-FGCD film performs very small friction coefficient and great friction behavior owing to its high surface smoothness, and meanwhile it also has excellent wear resistance because of the relatively high hardness of the surface FGD film and the extremely high hardness of the middle UMCD film. Moreover, under the industrial conditions for producing low-carbon steel wires, this composite film can sufficiently prolong the working lifetime of the drawing dies and improve their application effects. This research develops a novel composite diamond films owning great comprehensive properties, which have great potentials as protecting coatings on working surfaces of the wear-resistant and anti-frictional

  20. Tester status report: October-December 1978

    Energy Technology Data Exchange (ETDEWEB)

    Draut, C.F.

    1979-02-09

    This report details the status of the testers which provide the testing support of timers, actuators, detonators, firing sets, transducers, isolators, and pyrospacers during the time period of October through December 1978.

  1. Tester status report: April-June 1979

    Energy Technology Data Exchange (ETDEWEB)

    Draut, C.F.

    1979-08-31

    This report details tester status and activities in support of testing of timers, actuators, detonators, firing sets, transducers, isolators, and pyrospacers for the period of April through June 1979.

  2. Armstrong Laboratory Space Visual Function Tester Program

    Science.gov (United States)

    Oneal, Melvin R.; Task, H. Lee; Gleason, Gerald A.

    1992-01-01

    Viewgraphs on space visual function tester program are presented. Many astronauts and cosmonauts have commented on apparent changes in their vision while on-orbit. Comments have included descriptions of earth features and objects that would suggest enhanced distance visual acuity. In contrast, some cosmonaut observations suggest a slight loss in their object discrimination during initial space flight. Astronauts have also mentioned a decreased near vision capability that did not recover to normal until return to earth. Duntley space vision experiment, USSR space vision experiments, and visual function testers are described.

  3. Comparative investigations of tablet crushing force testers

    DEFF Research Database (Denmark)

    Sonnergaard, Jørn; Jensen, C.G.; Poulsen, L.

    2005-01-01

    The performance of 16 tablet breaking force testers was evaluated in terms of accuracy, reproducibility and repeatability. Three tablet formulations with different plastic or brittle deformation mechanisms and with target breaking forces of 50, 100 and 150 N were tested. Statistically significant...... by the concept of components of variance was 5-7 % depending on the model tablet excipient. The standard deviation within testers (repeatability) was affected by the type of model formulation showing increasing variability with increasing brittleness of the compressed material. No specific effect of altering...

  4. Gimbaled-shoulder friction stir welding tool

    Science.gov (United States)

    Carter, Robert W. (Inventor); Lawless, Kirby G. (Inventor)

    2010-01-01

    A gimbaled-shoulder friction stir welding tool includes a pin and first and second annular shoulders coupled to the pin. At least one of the annular shoulders is coupled to the pin for gimbaled motion with respect thereto as the tool is rotated by a friction stir welding apparatus.

  5. 21 CFR 886.1170 - Color vision tester.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Color vision tester. 886.1170 Section 886.1170...) MEDICAL DEVICES OPHTHALMIC DEVICES Diagnostic Devices § 886.1170 Color vision tester. (a) Identification. A color vision tester is a device that consists of various colored materials, such as colored...

  6. 21 CFR 870.3720 - Pacemaker electrode function tester.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pacemaker electrode function tester. 870.3720... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Prosthetic Devices § 870.3720 Pacemaker electrode function tester. (a) Identification. A pacemaker electrode function tester is a device which is...

  7. A Tester for Carbon Nanotube Mode Lockers

    Science.gov (United States)

    Song, Yong-Won; Yamashita, Shinji

    2007-05-01

    We propose and demonstrate a tester for laser pulsating operation of carbon nanotubes employing a circulator with the extra degree of freedom of the second port to access diversified nanotube samples. The nanotubes are deposited onto the end facet of a dummy optical fiber by spray method that guarantees simple sample loading along with the minimized perturbation of optimized laser cavity condition. Resultant optical spectra, autocorrelation traces and pulse train of the laser outputs with qualified samples are presented.

  8. Scanning-electron-microscope used in real-time study of friction and wear

    Science.gov (United States)

    Brainard, W. A.; Buckley, D. H.

    1975-01-01

    Small friction and wear apparatus built directly into scanning-electron-microscope provides both dynamic observation and microscopic view of wear process. Friction and wear tests conducted using this system have indicated that considerable information can readily be gained.

  9. Financial Frictions

    DEFF Research Database (Denmark)

    Vestergaard Jensen, Mads

    frictions, a call option should never be exercised early, but only at expiration or just before the underlying stock pays a dividend. Chapter one of this thesis shows that suffciently severe frictions can make early exercise optimal. Short-sale costs especially represent an important driver of early...

  10. Friction Model for FEM Simulation of Sheet Metal Forming Operations

    Science.gov (United States)

    Keum, Y. T.; Wagoner, R. H.; Lee, J. K.

    2004-06-01

    In order to find the effect of frictional characteristics, lubricant viscosity, tool geometry, and forming speed on the sheet metal forming, a friction tester was designed and manufactured. Friction tests were performed using drawing oils, various tool radii and forming speeds for aluminum alloy sheets, galvanized steels sheets and cold rolled steel sheets. From the experimental observation, the mathematical friction model considering lubricant viscosity, sheet surface roughness and hardness, punch corner radii, and punch speed is developed. By comparing the punch load found by FEM using the proposed friction model with that of experimental measurement when the steel sheets are formed in 2-D geometry in dry and lubricating conditions, the validity and accuracy of the mathematical friction model are demonstrated.

  11. Uniform Design of Optimizing Formulation of Friction Materials with Composite Mineral Fiber (CMF) and Their Friction and Wear Behavior

    Science.gov (United States)

    Yang, Yazhou; Jiang, Man; Xu, Jie; Ma, Yunhai; Tong, Jin

    2012-04-01

    In this work, the uniform design method was applied to arrange the experimental scheme for optimizing formulation of friction materials. The friction and wear of the friction materials based on the optimized formulation was carried out on a constant speed friction tester (JF150D-II), using pad-on-disc contact mode against gray cast iron disc. The worn surfaces of the friction materials were examined by scanning electron microscopy (JSM5310) and the friction mechanism was discussed. The results showed that the uniform design method was appropriate for finding the optimum formulation of the friction materials with better properties. Compared with two conventional friction materials, the friction materials based on the optimized formulation possessed higher and stable friction coefficient and higher wear resistance, even at the disc temperature of 350°C. The adhesion, strain fatigue and abrasive wear were the main wear mechanisms of the friction materials. Tribo-chemical phenomenon and plastic deformation existed on the worn surface layer.

  12. Friction and friction-generated temperature at a polymer-metal interface

    Science.gov (United States)

    Price, H. L.; Burks, H. D.

    1974-01-01

    Results of friction and thermal tests of molded polyimide and pyrrone polymers are presented. The coefficient of sliding friction up to surface velocities of 2 m/sec and the coefficient of thermal expansion from 300 to 500 K were measured. An apparatus was constructed to measure simultaneously the coefficient of sliding friction and the friction-generated temperature. Measurements were made at a nominal pressure-velocity product of 0.25 MN/msec and at temperatures between 300 and 500 K.

  13. Advanced adhesion and friction measurement system

    Science.gov (United States)

    Li, Meng; Huang, Wei; Wang, Xiaolei

    2017-03-01

    An advanced micro-force tester for investigating the micromechanical behavior of various patterned surfaces in dry and wet conditions is presented in this paper. The parallel slice-beam configuration of the tester not only eliminates the large load-dependent slope and tangential displacement at the free end that is found in a single beam system, but also performs a trans-scale deflection with high sensitivity and linearity for force sensing. Meanwhile, the simple structure is characterized by low cost, high efficiency, and ease of fabrication. An integrated nano- and micro-stage comprise the mobile table to produce a large stroke with high resolution, which is specifically required in wet adhesion testing because of the formation of a long liquid bridge. Preliminary experiments of adhesion and friction conducted using PDMS pillars with a plano-convex lens validated the feasibility of this setup.

  14. Development of transmission error tester for face gears

    Science.gov (United States)

    Shi, Zhao-yao; Lu, Xiao-ning; Chen, Chang-he; Lin, Jia-chun

    2013-10-01

    A tester for measuring face gears' transmission error was developed based on single-flank rolling principle. The mechanical host was of hybrid configuration of the vertical and horizontal structures. The tester is mainly constituted by base, precision spindle, grating measurement system and control unit. The structure of precision spindles was designed, and rotation accuracy of the spindleswas improved. The key techniques, such as clamping, positioning and adjustment of the gears were researched. In order to collect the data of transmission error, high-frequency clock pulse subdivision count method with higher measurement resolution was proposed. The developed tester can inspect the following errors, such as transmission error of the pair, tangential composite deviation for the measured face gear, pitch deviation, eccentricity error, and so on. The results of measurement can be analyzed by the tester; The tester can meet face gear quality testing requirements for accuracy of grade 5.

  15. Design of a LOW Cost IC Tester

    Directory of Open Access Journals (Sweden)

    Liakot Ali

    2005-01-01

    Full Text Available Low cost Integrated Circuit (IC testing is now a burning issue in semiconductor technology. Conventional IC tester, Automatic Test Equipment (ATE, cannot cope with the today’s continuously increasing complexities in IC technology. Deterministic algorithm, which is an idea of 1960’s, is adopted in the ATE. Recently pseudo-random testing approach of IC testing has been emerged as an economically viable alternative to the expensive deterministic testing approach. This study introduces the design of a System-on-a-chip (Soc implementing pseudo-random test technique for low cost IC testing with reliable performance. It is capable of testing combinational circuits as well as sequential circuits with scan-port facilities efficiently. It can also be used for testing Printed Circuit Board (PCB interconnection faults.

  16. Sixty-four-Channel Inline Cable Tester

    Science.gov (United States)

    2008-01-01

    Faults in wiring are a serious concern for the aerospace and aeronautics (commercial, military, and civil) industries. A number of accidents have occurred because faulty wiring created shorts or opens that resulted in the loss of control of the aircraft or because arcing led to fires and explosions. Some of these accidents have resulted in the massive loss of lives (such as in the TWA Flight 800 accident). Circuits on the Space Shuttle have also failed because of faulty insulation on wiring. STS-93 lost power when a primary power circuit in one engine failed and a second engine had a backup power circuit fault. Cables are usually tested on the ground after the crew reports a fault encountered during flight. Often such failures result from vibration and cannot be replicated while the aircraft is stationary. It is therefore important to monitor faults while the aircraft is in operation, when cables are more likely to fail. Work is in progress to develop a cable fault tester capable of monitoring up to 64 individual wires simultaneously. Faults can be monitored either inline or offline. In the inline mode of operation, the monitoring is performed without disturbing the normal operation of the wires under test. That is, the operations are performed unintrusively and are essentially undetectable for the test signal levels are below the noise floor. A cable can be monitored several times per second in the offline mode and once a second in the inline mode. The 64-channel inline cable tester not only detects the occurrence of a fault, but also determines the type of fault (short/open) and the location of the fault. This will enable the detection of intermittent faults that can be repaired before they become serious problems.

  17. The frictional coefficient of the temporomandibular joint and its dependency on the magnitude and duration of joint loading.

    Science.gov (United States)

    Tanaka, E; Kawai, N; Tanaka, M; Todoh, M; van Eijden, T; Hanaoka, K; Dalla-Bona, D A; Takata, T; Tanne, K

    2004-05-01

    In synovial joints, friction between articular surfaces leads to shear stress within the cartilaginous tissue, which might result in tissue rupture and failure. Joint friction depends on synovial lubrication of the articular surfaces, which can be altered due to compressive loading. Therefore, we hypothesized that the frictional coefficient of the temporomandibular joint (TMJ) is affected by the magnitude and duration of loading. We tested this by measuring the frictional coefficient in 20 intact porcine TMJs using a pendulum-type friction tester. The mean frictional coefficient was 0.0145 (SD 0.0027) after a constant loading of 50 N during 5 sec. The frictional coefficient increased with the length of the preceding loading duration and exceeded 0.0220 (SD 0.0014) after 1 hr. Application of larger loading (80 N) resulted in significantly larger frictional coefficients. In conclusion, the frictional coefficient in the TMJ was proportional to the magnitude and duration of joint loading.

  18. Skin friction related behaviour of artificial turf systems.

    Science.gov (United States)

    Tay, Sock Peng; Fleming, Paul; Hu, Xiao; Forrester, Steph

    2017-08-01

    The occurrence of skin friction related injuries is an issue for artificial turf sports pitches and remains a barrier to their acceptance. The purpose of this study was to evaluate the current industry standard Securisport® Sports Surface Tester that measures skin surface related frictional behaviour of artificial turf. Little research has been published about the device and its efficacy, despite its widespread use as a standard FIFA test instrument. To achieve a range of frictional behaviours, several "third generation" (3G) carpet and infill combinations were investigated; friction time profiles throughout the Securisport rotations were assessed in combination with independent measurements of skin roughness before and after friction testing via 3D surface scanning. The results indicated that carpets without infill had greatest friction (coefficients of friction 0.97-1.20) while those completely filled with sand or rubber had similar and lower values independent of carpet type (coefficient of friction (COF) ≈0.57). Surface roughness of a silicone skin (s-skin) decreased after friction testing, with the largest change on sand infilled surfaces, indicating an "abrasive" polishing effect. The combined data show that the s-skin is damaged in a surface-specific manner, thus the Securisport COF values appear to be a poor measure of the potential for skin abrasion. It is proposed that the change in s-skin roughness improves assessment of the potential for skin damage when players slide on artificial turf.

  19. TRANSFORMER APPARATUS

    Science.gov (United States)

    Wolfgang, F.; Nicol, J.

    1962-11-01

    Transformer apparatus is designed for measuring the amount of a paramagnetic substance dissolved or suspended in a diamagnetic liquid. The apparatus consists of a cluster of tubes, some of which are closed and have sealed within the diamagnetic substance without any of the paramagnetic material. The remaining tubes are open to flow of the mix- ture. Primary and secondary conductors are wrapped around the tubes in such a way as to cancel noise components and also to produce a differential signal on the secondaries based upon variations of the content of the paramagnetic material. (AEC)

  20. Dry friction and wear properties of intermetallics MoSi2

    Institute of Scientific and Technical Information of China (English)

    张厚安; 刘心宇; 陈平; 唐果宁

    2001-01-01

    The dry friction and wear properties of intermetallics MoSi2 against 45 steel under different loads were investigated with M-2 type friction and wear tester. Scanning electric microscope (SEM) equipment with microprobe was employed to analyze the morphology of the friction surface. Results show that the dry friction and wear properties are deeply affected by load. The wear rate of MoSi2 at the load of 80 N is the maximum which is 36.1 μg/m. On the condition of the load of 150 N, MoSi2 material has the better friction and wear properties: friction coefficient is 0.28 and wear rate is 10.6μg/m. With the load increasing, the main friction mechanisms change from microslip and plastic deformation to adhesive effect, and the main wear mechanisms change from plough-groove wear and oxidation-fatigue wear to adhesive wear.

  1. Logic Tester for the Classification of Cyberterrorism Attacks

    CSIR Research Space (South Africa)

    Veerasamy, N

    2015-01-01

    Full Text Available for cyberterrorism. This proposed definition is founded on the definition for traditional terrorism and incorporates elements of the international understanding of cyberterrorism. The research future presents a Logic Tester that uses Boolean logic to test...

  2. State of the art of impact testers for spot welds

    Institute of Scientific and Technical Information of China (English)

    Hua Fuan; Ma Mingtu; Li Jianping; Wang Guodong

    2014-01-01

    Impact testing is a primary method to evaluate the impact property of resistance spot welding,which is an important quality index in automotive industry. For testing impact properties of spot welds,many custo-mized testers have been developed. This paper summarized some of the impact testers reported in open litera-tures and the emphasis was placed on the equipment structures,functions,technical parameters,advantages and disadvantage,etc. Some key issues about the development of the testers such as kinematic energy input mode,fixture design,combined load testing,sensor and data acquisition were discussed. Finally,the prob-lems and prospects in the research and development of impact testers for spot welds were pointed out.

  3. Prehensile apparatus

    Science.gov (United States)

    Smith, C.M.

    1993-10-12

    The present invention relates to an apparatus for handling a workpiece comprising a vessel that is longitudinally extensible and pressurizable, and a nonextensible and laterally flexible member on the vessel. The member constrains one side of the vessel to be nonextensible, causing the vessel to bend in the direction of the nonextensible member when pressurized. 8 figures.

  4. Friction reduction using discrete surface textures: principle and design

    Science.gov (United States)

    Hsu, Stephen M.; Jing, Yang; Hua, Diann; Zhang, Huan

    2014-08-01

    There have been many reports on the use of dimples, grooves, and other surface textures to control friction in sliding interfaces. The effectiveness of surface textures in friction reduction has been demonstrated in conformal contacts under high speed low load applications such as mechanical seals and automotive water pump seals, etc., resulting in reduced friction and longer durability. For sliding components with higher contact pressures or lower speeds, conflicting results were reported. Reasons for the inconsistency may be due to the differences in texture fabrication techniques, lack of dimple size and shape uniformity, and different tester used. This paper examines the basic principles on which surface textural patterns influence friction under the three principle lubrication regimes: hydrodynamic, elastohydrodynamic, and boundary lubrication regimes. Our findings suggest that each regime requires specific dimple size, shape, depth, and areal density to achieve friction reduction. Control experiments were also conducted to explore mechanisms of friction reduction. The dimple geometric shape and the dimple's orientation with respect to the sliding direction influence friction significantly. The underlying mechanisms for friction control via textures are discussed.

  5. The Influence of Normal Load and Sliding Speed on Frictional Properties of Skin

    Institute of Scientific and Technical Information of China (English)

    Wei Tang; Shi-rong Ge; Hua Zhu; Xi-chuan Cao; Ning Li

    2008-01-01

    The study of frictional properties of human skin is important for medical research, skin care products and textile exploitation. In order to investigate the influence of normal load and sliding speed on the frictional properties of skin and its possible mechanism, tests were carried out on a multi-specimen friction tester. When the normal load increases from 0.1 N to 0.9 N,normal displacement and the friction coefficient of skin increase. The friction coefficient is dependent on the load, indicating that both adhesion and deformation contribute to the friction behaviour. The deformation friction was interpreted using the plough model of fiiction. When sliding speed increases from 0.5 mm·s-1 to 4 mm·s-1,the friction coefficient increases and "stick-slip" phenomena increase, indicating that hysteretic friction contributes to the friction. The hysteretic friction was interpreted using schematic of energy translation during the rigid spherical probe sliding on the soft skin surface, which provides an explanation for the influence of the sliding speed on the frictional characteristics of the skin.

  6. Friction and Wear Behaviors of Nano-Silicates in Water

    Institute of Scientific and Technical Information of China (English)

    Chen Boshui; Lou Fang; Fang Jianhua; Wang Jiu; Li Jia

    2009-01-01

    Nano-metric magnesium silicate and zinc silicate with particle size of about 50--70nm were prepared in water by the method of chemical deposition. The antiwear and friction reducing abilities of the nano-silicates, as well as their compos-ites with oleie acid tri-ethanolamine (OATEA), were evaluated on a four-ball friction tester. The topographies and tribochemical features of the worn surfaces were analyzed by scanning electron microscope (SEM) and X-ray photoelectron spectroscope (XPS). Results show that nano-silicates alone provide poor antiwear and friction reducing abilities in water, but exhibits excellent synergism with OATEA in reducing friction and wear. The synergism in reducing friction and wear between naao-silicates and OATEA does exist almost regardless of particle sizes and species, and may be attributed, on one hand, to the formation of an adsorption film of OATEA, and, on the other hand, to the formation oftdbochemical species of silicon dioxide and iron oxides on the friction surfaces. Tribo-reactions and tribo-adsorptions of nano-silicates and OATEA would produce hereby an effective composite boondary lubrication film, which could efficiently enhance the anti-wear and friction-reducing abilities of water.

  7. Development of a Drop Tester for Portable Electronic Products

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Portable electronic products are susceptible to accidental drop impact which can cause various functional and physical damage. This paper first presents a patent pending drop tester which allows portable electronic products free drop at any orientation and drop height, and then introduces the drop tester experiment setup and its design principle. Using a cellular phone as an experiment object, we obtain some data such as the impact forces, the impact accelerations, and the strain of an interested spot. By analyzing experiment data the influence of impact to products in various states is investigated with the aim to provide help for the design of products and improvement of reliability.

  8. Influence of loading and rotation speed on Friction and Wear properties of CuAlBi Alloy

    Institute of Scientific and Technical Information of China (English)

    Liu Rongchang; Dong Litao; Li Xingyuan; Chen Xiuhong

    2007-01-01

    The variation of the friction coefficient of the CuAlBi alloy at different connecting loading and friction speed were investigated by using MMU-5G sliding friction-wear tester, besides, the wear mass loss of the CuAlBi alloy was measured, and the influence of loading and rotation speed on friction and wear properties of CuAlBi alloy was also discussed. The results show that the friction coefficient increase then decrease with increase of connecting loading as well as decreases with increase of friction speed, and the wear loss mass increases with increase of connecting loading and friction speed. As a result, the wear failure form of CuAlBi alloy is mainly ploughing.

  9. Wear and Friction Behavior of Metal Impregnated Microporous Carbon Composites

    Science.gov (United States)

    Goller, Gultekin; Koty, D. P.; Tewari, S. N.; Singh, M.; Tekin, A.

    1996-01-01

    Metal-matrix composites have been prepared by pressure-infiltration casting of copper-base alloy melts into microporous carbon preforms. The carbon preforms contained varying proportions of amorphous carbon and graphite. Load dependence of the wear and friction behavior of the composite pins has been examined under ambient conditions against cast-iron plates, using a pin-on-plate reciprocating wear tester. The wear resistance of the composite is significantly improved, as compared with the base alloy. Contrary to the normally expected behavior, the addition of graphite to the amorphous carbon does not reduce the friction coefficient, especially at high loads. The wear and friction behavior of the composites is very sensitive to the size and distribution of the microstructural constituents.

  10. Acoustics of friction.

    Science.gov (United States)

    Akay, Adnan

    2002-04-01

    This article presents an overview of the acoustics of friction by covering friction sounds, friction-induced vibrations and waves in solids, and descriptions of other frictional phenomena related to acoustics. Friction, resulting from the sliding contact of solids, often gives rise to diverse forms of waves and oscillations within solids which frequently lead to radiation of sound to the surrounding media. Among the many everyday examples of friction sounds, violin music and brake noise in automobiles represent the two extremes in terms of the sounds they produce and the mechanisms by which they are generated. Of the multiple examples of friction sounds in nature, insect sounds are prominent. Friction also provides a means by which energy dissipation takes place at the interface of solids. Friction damping that develops between surfaces, such as joints and connections, in some cases requires only microscopic motion to dissipate energy. Modeling of friction-induced vibrations and friction damping in mechanical systems requires an accurate description of friction for which only approximations exist. While many of the components that contribute to friction can be modeled, computational requirements become prohibitive for their contemporaneous calculation. Furthermore, quantification of friction at the atomic scale still remains elusive. At the atomic scale, friction becomes a mechanism that converts the kinetic energy associated with the relative motion of surfaces to thermal energy. However, the description of the conversion to thermal energy represented by a disordered state of oscillations of atoms in a solid is still not well understood. At the macroscopic level, friction interacts with the vibrations and waves that it causes. Such interaction sets up a feedback between the friction force and waves at the surfaces, thereby making friction and surface motion interdependent. Such interdependence forms the basis for friction-induced motion as in the case of

  11. Software testing an ISTQB-BCS certified tester foundation guide

    CERN Document Server

    Hambling, Brian; Samaroo, Angelina; Thompson, Geoff; Williams, Peter; Hambling, Brian

    2015-01-01

    This practical guide provides insight into software testing, explaining the basics of the testing process and how to perform effective tests. It provides an overview of different techniques and how to apply them. It is the best-selling official textbook of the ISTQB-BCS Certified Tester Foundation Level.

  12. Colour of Tester Effects on Children's Expressed Attitudes.

    Science.gov (United States)

    Thomas, K. C.

    1978-01-01

    Discusses a study of student attitudes, preferences, and stereotyping among White Britons and West Indian students in an English secondary school. Findings indicated that factors such as the race of the tester influenced the test situation. For journal availability, see SO 506 785. (DB)

  13. Piezoelectric Bolt Breakers and Bolt Fatigue Testers

    Science.gov (United States)

    Sherrit, Stewart; Badescu, Mircea; Bar-Cohen, Yoseph; Barengoltz, Jack; Heckman, Vanessa

    2008-01-01

    catastrophic misfire. In fatigue-testing applications, devices of the proposed type would offer advantages of compactness and low cost, relative to conventional fatigue- testing apparatuses. In both structural- separation and fatigue-testing applications, bolts to be broken or tested could be instrumented with additional ultrasonic transducers for monitoring of pertinent physical properties and of fatigue failure processes.

  14. Friction and wear performances of borates and lanthanum chloride in water

    Institute of Scientific and Technical Information of China (English)

    CHEN Boshui; FANG Jianhua; WANG Jiu; LI Jia; LOU Fang

    2008-01-01

    The antiwear and friction-reducing performances of sodium borate, potassium borate and lanthanum chloride in water were evaluated on a four-ball friction tester. The topographies, element distribution and chemical characteristics of the worn surfaces were investigated by scanning electron microscope (SEM), energy dispersion of X-ray (EDX) and X-ray photoelectron spectroscope (XPS). The results indicated that sodium borate, potassium borate and lanthanum chloride increased extreme pressure, antiwear and friction-reducing capacities of water to a certain extent, of which potassium borate was the best candidate. Combination of lanthanum chloride with sodium borate and potassium borate respectively further improved antiwear and friction-reducing capacities. Scratches of worn surfaces lubricated with water containing borates and lanthanum chloride were less severe than those lubricated with water containing borates alone. A tribochemical film mainly composed of oxides of lanthanum, boron and iron reduced friction and wear for water lubricant formulated with both borates and lanthanum chloride.

  15. Sensitivity to friction for primary explosives.

    Science.gov (United States)

    Matyáš, Robert; Šelešovský, Jakub; Musil, Tomáš

    2012-04-30

    The sensitivity to friction for a selection of primary explosives has been studied using a small BAM friction apparatus. The probit analysis was used for the construction of a sensitivity curve for each primary explosive tested. Two groups of primary explosives were chosen for measurement (a) the most commonly used industrially produced primary explosives (e.g. lead azide, tetrazene, dinol, lead styphnate) and (b) the most produced improvised primary explosives (e.g. triacetone triperoxide, hexamethylenetriperoxide diamine, mercury fulminate, acetylides of heavy metals). A knowledge of friction sensitivity is very important for determining manipulation safety for primary explosives. All the primary explosives tested were carefully characterised (synthesis procedure, shape and size of crystals). The sensitivity curves obtained represent a unique set of data, which cannot be found anywhere else in the available literature. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Sensitivity to friction for primary explosives

    Energy Technology Data Exchange (ETDEWEB)

    Matyas, Robert, E-mail: robert.matyas@upce.cz [Institute of Energetic Materials, Faculty of Chemical Technology, University of Pardubice, Pardubice 532 10 (Czech Republic); Selesovsky, Jakub; Musil, Tomas [Institute of Energetic Materials, Faculty of Chemical Technology, University of Pardubice, Pardubice 532 10 (Czech Republic)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer The friction sensitivity of 14 samples of primary explosives was determined. Black-Right-Pointing-Pointer The same apparatus (small scale BAM) and the same method (probit analysis) was used. Black-Right-Pointing-Pointer The crystal shapes and sizes were documented with microscopy. Black-Right-Pointing-Pointer Almost all samples are less sensitive than lead azide, which is commercially used. Black-Right-Pointing-Pointer The organic peroxides (TATP, DADP, HMTD) are not as sensitive as often reported. - Abstract: The sensitivity to friction for a selection of primary explosives has been studied using a small BAM friction apparatus. The probit analysis was used for the construction of a sensitivity curve for each primary explosive tested. Two groups of primary explosives were chosen for measurement (a) the most commonly used industrially produced primary explosives (e.g. lead azide, tetrazene, dinol, lead styphnate) and (b) the most produced improvised primary explosives (e.g. triacetone triperoxide, hexamethylenetriperoxide diamine, mercury fulminate, acetylides of heavy metals). A knowledge of friction sensitivity is very important for determining manipulation safety for primary explosives. All the primary explosives tested were carefully characterised (synthesis procedure, shape and size of crystals). The sensitivity curves obtained represent a unique set of data, which cannot be found anywhere else in the available literature.

  17. Scale dependence of rock friction at high work rate.

    Science.gov (United States)

    Yamashita, Futoshi; Fukuyama, Eiichi; Mizoguchi, Kazuo; Takizawa, Shigeru; Xu, Shiqing; Kawakata, Hironori

    2015-12-10

    Determination of the frictional properties of rocks is crucial for an understanding of earthquake mechanics, because most earthquakes are caused by frictional sliding along faults. Prior studies using rotary shear apparatus revealed a marked decrease in frictional strength, which can cause a large stress drop and strong shaking, with increasing slip rate and increasing work rate. (The mechanical work rate per unit area equals the product of the shear stress and the slip rate.) However, those important findings were obtained in experiments using rock specimens with dimensions of only several centimetres, which are much smaller than the dimensions of a natural fault (of the order of 1,000 metres). Here we use a large-scale biaxial friction apparatus with metre-sized rock specimens to investigate scale-dependent rock friction. The experiments show that rock friction in metre-sized rock specimens starts to decrease at a work rate that is one order of magnitude smaller than that in centimetre-sized rock specimens. Mechanical, visual and material observations suggest that slip-evolved stress heterogeneity on the fault accounts for the difference. On the basis of these observations, we propose that stress-concentrated areas exist in which frictional slip produces more wear materials (gouge) than in areas outside, resulting in further stress concentrations at these areas. Shear stress on the fault is primarily sustained by stress-concentrated areas that undergo a high work rate, so those areas should weaken rapidly and cause the macroscopic frictional strength to decrease abruptly. To verify this idea, we conducted numerical simulations assuming that local friction follows the frictional properties observed on centimetre-sized rock specimens. The simulations reproduced the macroscopic frictional properties observed on the metre-sized rock specimens. Given that localized stress concentrations commonly occur naturally, our results suggest that a natural fault may lose its

  18. Scale effects in sliding friction: An experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Blau, P.J.

    1991-07-24

    Solid friction is considered by some to be a fundamental property of two contacting materials, while others consider it to be a property of the larger tribosystem in which the materials are contained. A set of sliding friction experiments were designed to investigate the hypothesis that the unlubricated sliding friction between two materials is indeed a tribosystems-related property and that the relative influence of the materials properties or those of the machine on friction varies from one situation to another. Three tribometers were used: a friction microprobe (FMP), a typical laboratory-scale reciprocating pin-on-flat device, and a heavy-duty commercial wear tester. The slider material was stainless steel (AISI 440C) and the flat specimen material was an ordered alloy of Ni{sub 3}Al (IC-50). Sphere-on-flat geometry was used at ambient conditions and at normal forces ranging from 0.01 N to 100 N and average sliding velocities of 0.01 to 100.0 mm/s. The nominal, steady-state sliding friction coefficient tended to decrease with increases in normal force for each of the three tribometers, and the steady state value of sliding friction tended to increase as the mass of the machine increased. The variation of the friction force during sliding was also a characteristic of the test system. These studies provide further support to the idea that the friction of both laboratory-scale and engineering tribosystems should be treated as a parameter which may take on a range of characteristic values and not conceived as having a single, unique value for each material pair.

  19. Dynamic characterization of a new accelerated heart valve tester.

    Science.gov (United States)

    Menzler, F; Haubold, A D; Hwang, N H

    1997-01-01

    This paper presents a new accelerated prosthetic heart valve tester prototype that incorporates a camshaft and poppet valves. A three element Windkessel system is used to mimic the afterload of the human systemic circulation. The device is capable of testing eight valves simultaneously at a rate up to 1,250 cycles/min, while the flow rate, the pressure, and the valve loading can be monitored and adjusted individually. The tester was characterized and calibrated using a set of eight Carpentier-Edwards bioprostheses at a flow rate varying between 3 and 5 L/min. The experiment was carried out with the pressure difference across the closed heart valve maintained between 140 and 190 mmHg. Smooth and complete opening and closing of the valve leaflets was achieved at all cycling rates. This confirms that the velocity profiles approaching the test valves were uniform, an important factor that allows the test valves to open and close synchronously each time.

  20. Two-dimensional field model for single-sheet tester

    CERN Document Server

    Ivanyi, A

    2003-01-01

    The investigation of the magnetic field in a circular-shaped single-sheet tester is developed under circular polarised field intensity as well as flux density. The non-linear anisotropy of the material is represented by a vector realisation of the Jiles-Atherton hysteresis operator. The monitored data of the components in the field vectors are simulated with the averaged values of the field resulted by the numerical analysis of the non-linear eddy current problem.

  1. In-Place Filter Tester Instrument for Nuclear Material Containers.

    Science.gov (United States)

    Brown, Austin D; Moore, Murray E; Runnels, Joel T; Reeves, Kirk

    2016-05-01

    A portable instrument was developed to determine filter clogging and container leakage of in-place nuclear material storage canisters. This paper describes the development of an in-place filter tester for determining the "as found" condition of unopened canisters. The U.S. Department of Energy uses several thousand canisters for nuclear material storage, and air filters in the canister lids allow gases to escape while maintaining an equilibrated pressure without release of radioactive contamination. Diagnosing the filter condition and canister integrity is important for ensuring worker and public safety. Customized canister interfaces were developed for suction clamping (during tests) to two of the canister types in use at Los Alamos National Laboratory. Experimental leakage scenarios included: O-rings fouled with dust, cracked O-rings, and loose canister lids. The prototype tester has a measurement range for air leakage rates from 8.2 × 10 mL s up to 3.0 × 10 mL s. This is sufficient to measure a leak rate of 3.4 × 10 mL s, which is the Los Alamos helium leak criterion for post-drop tested canisters. The In-Place-Filter-Tester cannot measure to the lower value of the helium leak criterion for pre-drop tested canisters (1.0 × 10 mL s). However, helium leak testing requires canister disassembly, while the new in-place filter tester is able to assess the assembled condition of as-found and in-situ canisters.

  2. A High Temperature Hermetic Primer and a Variable Spring Tester

    Energy Technology Data Exchange (ETDEWEB)

    Begeal, D.R.

    1994-05-01

    Percussion primers are used at Sandia to ignite energetic components such as pyrotechnic actuators and thermal batteries. This report describes a High Temperature Hermetic Primer (HTHP) that was developed to replace a previous G16 Percussion Primer Subassembly (Gl6PPS). The ignition mix in these primers is the same as in the discontinued Remington 44G16 (KC1O{sub 3}, SbS{sub 3}, and Ca{sub 2}Si). The HTHP has nearly the same sensitivity as the 44G16 and a significantly lower sensitivity than the G16PPS. In parallel with the HTHP development, we also designed a Variable Spring Tester (VST) to determine percussion primer ignition sensitivity with firing pins that have the same mass as those used in field applications. The tester is capable of accelerating firing pins over a velocity range of 100 to 600 inches per second for pins weighing up to 6 grams. The desired impulse can be preselected with an accuracy of better than {plus_minus}1%. The actual impulse is measured on every shot. The VST was characterized using the WW42Cl primer, as well as with the G16PPS and the HTHP. Compared to data from conventional ball drop testers, we found that ignition sensitivities were lower and there was less scatter in the sensitivity data. Our experiments indicate that ignition sensitivity is not strictly energy dependent, but also depends on the rate of deposition, or firing pin velocity in this case. Development results for the HTHP and Variable Spring Tester are discussed and design details are shown.

  3. Computational Fluid Dynamics Analysis of the Venturi Dustiness Tester.

    Science.gov (United States)

    Dubey, Prahit; Ghia, Urmila; Turkevich, Leonid A

    2017-05-01

    Dustiness quantifies the propensity of a finely divided solid to be aerosolized by a prescribed mechanical stimulus. Dustiness is relevant wherever powders are mixed, transferred or handled, and is important in the control of hazardous exposures and the prevention of dust explosions and product loss. Limited quantities of active pharmaceutical powders available for testing led to the development (at University of North Carolina) of a Venturi-driven dustiness tester. The powder is turbulently injected at high speed (Re ~ 2 × 10(4)) into a glass chamber; the aerosol is then gently sampled (Re ~ 2 × 10(3)) through two filters located at the top of the chamber; the dustiness index is the ratio of sampled to injected mass of powder. Injection is activated by suction at an Extraction Port at the top of the chamber; loss of powder during injection compromises the sampled dustiness. The present work analyzes the flow inside the Venturi Dustiness Tester, using an Unsteady Reynolds-Averaged Navier-Stokes formulation with the k-ω Shear Stress Transport turbulence model. The simulation considers single-phase flow, valid for small particles (Stokes number Stk <1). Results show that ~ 24% of fluid-tracers escape the tester before the Sampling Phase begins. Dispersion of the powder during the Injection Phase results in a uniform aerosol inside the tester, even for inhomogeneous injections, satisfying a necessary condition for the accurate evaluation of dustiness. Simulations are also performed under the conditions of reduced Extraction-Port flow; results confirm the importance of high Extraction-Port flow rate (standard operation) for uniform distribution of fluid tracers. Simulations are also performed under the conditions of delayed powder injection; results show that a uniform aerosol is still achieved provided 0.5 s elapses between powder injection and sampling.

  4. Friction characteristics of trocars in laparoscopic surgery.

    Science.gov (United States)

    Alazmani, Ali; Roshan, Rupesh; Jayne, David G; Neville, Anne; Culmer, Peter

    2015-04-01

    This article investigates the friction characteristics of the instrument-trocar interface in laparoscopic surgery for varying linear instrument velocities, trocar seal design and material, and trocar tilt. Furthermore, the effect of applying lubrication at the instrument-trocar seal interface on friction was studied. A friction testing apparatus was designed and built to characterise the resistance force at the instrument-trocar interface as a function of the instrument's linear movement in the 12-mm trocar (at constant velocity) for different design, seal material, and angle of tilt. The resistance force depended on the trocar seal design and material properties, specifically surface roughness, elasticity, hardness, the direction of movement, and the instrument linear velocity, and varied between 0.25 and 8 N. Lubricating the shaft with silicone oil reduced the peak resistance force by 75% for all trocars and eliminated the stick-slip phenomenon evident in non-lubricated cases. The magnitude of fluctuation in resistance force depends on the trocar design and is attributed to stick-slip of the sealing mechanism and is generally higher during retraction in comparison to insertion. Trocars that have an inlet seal made of rubber/polyurethane showed higher resistance forces during retraction. Use of a lubricant significantly reduced frictional effects. Comparisons of the investigated trocars indicate that a low friction port, providing the surgeon with improved haptic feedback, can be designed by improving the tribological properties of the trocar seal interface.

  5. Large Rotor Test Apparatus

    Data.gov (United States)

    Federal Laboratory Consortium — This test apparatus, when combined with the National Full-Scale Aerodynamics Complex, produces a thorough, full-scale test capability. The Large Rotor Test Apparatus...

  6. Effect of Tension on Friction Coefficient Between Lining and Wire Rope with Low Speed Sliding

    Institute of Scientific and Technical Information of China (English)

    PENG Yu-xing; ZHU Zhen-cai; CHEN Guo-an; CAO Guo-hua

    2007-01-01

    In order to obtain the exact friction coefficient between lining and wire rope, the tension of wire rope is studied as a factor which affects this coefficient. A mechanical model of a wire rope subjected to axial load was established to determine the torque of the wire rope. The contact motion between lining and wire rope was regarded as a screw rotation and the axial force of the lining resulting from the torque of the wire rope was analyzed. Theoretical formulas relating tension of the wire rope and the friction coefficient was obtained. Experiments between lining and wire rope with low sliding speed were carried out with friction tester made by us. Experimental results show that increment of the friction coefficient is proportional to that of the tension of the wire rope with a low sliding speed. The experimental results agree with the theoretical calculation; the errors are less than 6%, which proves the validity of the theoretical model.

  7. Pore roller filtration apparatus

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to the field of filtering, more precisely the present invention concerns an apparatus and a method for the separation of dry matter from a medium and the use of said apparatus. One embodiment discloses an apparatus for the separation of dry matter from a medium, comp...

  8. Measuring powder flowability with a modified Warren Spring cohesion tester

    Institute of Scientific and Technical Information of China (English)

    Salam A. Mohammed; Ezzat C. Abdullah; Derek Geldart; Abdul Aziz A. Raman

    2011-01-01

    The measurement of powder fiowability is a major concern for most industrial processes that deal with the handling of bulk solids as raw materials, intermediates, or products. The development of devices that measure the flowability of non-aerated powders has not progressed as rapidly as might have been hoped since most research activities have been based on various types of shear testers intended to aid the design of hoppers. A new flowability indicator named as weighted cohesion (WS) is established using newly improved version of direct cohesion texture. A cornerstone of the proposed technique is that the procedure is automated, using a digital Warren Spring tester called Warren Spring-University of Malaya cohesion tester (WSUMCT), thus making results operator-insensitive. Besides being a practical tool to diagnose the cohesion of experimental powders, the ratio between measured cohesion (using WSUMCT) and aerated density (using Hosokawa PT-S) provides us with a powerful technique to research fundamental particle internal cohesion forces directly and use these data to indicate the flowability. In this work, a series of fine (9.4 .μm) and coarse (60 μm) porous silica gel particle mixtures, and mixtures of fine (28 μm) and coarse (72 μm) glass ballotini as well, were used as test powders. The results from these tests agree well with relative flowability determined on our newly driven indicator using WSUMCT. The validation of aerated weighted cohesion (WSA) as a flowability indicator was authenticated by comparing the conducted parameter with established measured Hausner ratio (HR) and angle of repose (AoR).

  9. Temperature control strategy for a seal fatigue tester

    Directory of Open Access Journals (Sweden)

    M. Związek

    2008-08-01

    Full Text Available Purpose: The aim of the paper is optimization of a control strategy used in a seal fatigue tester.Design/methodology/approach: Analytical approach has been applied to get an understanding of a heat exchange process. It is required to optimize the control process algorithm.Findings: The initial control algorithm has been improved regarding numerous tests under different operating conditions. The final version of the control program allows to maintain the temperature according to the on-off strategy minimizing the temperature oscillations and potential overshoots.Research limitations/implications: It should be considered a new control strategy based on PID controller.Practical implications: The major component of the tester is the heat exchanger. It consists of a tube and embedded pipe circuit feeding with the external heating or cooling medium. The tube is a cylindrical housing where the seals are assembled at both sides. Two main pumps circulate the medium at a specified flow rate and pressure. The temperature is maintained to hold it almost constant during heating and cooling phases. Two thermocouples are placed close to the seals, and the one in the middle of the heat exchanger tube. The tester is equipped with a control system consisting of a PLC controller and LabView data acquisition application. It is possible to control the device remotely through LAN/WAN networks. The LabView application communicates with the controller via software with the use of PPI (Point-To-Point Interface protocol. A new control algorithm has allowed to perform tests according to testing specification without significant overshoots.Originality/value: On-off control algorithm has been proposed for a combined heating-cooling installation rarely using in the industrial solutions.

  10. Torsional friction damper optimization

    Science.gov (United States)

    Ye, Shaochun; Williams, Keith A.

    2006-06-01

    A new approach for the analysis of friction dampers is presented in this work. The exact form of the steady-state solution for a friction damper implemented on a primary system is developed and numerical solutions are used to determine the optimum friction in a friction damper applied to a specific primary system. When compared to classical results presented by earlier authors, the new approach provides a more optimal solution. In addition, viscous damping in the primary system may be included with the new analysis approach. The ability to optimize a friction damper when viscous damping is included in the primary system is a significant improvement over earlier methods and shows potential for serving as a guide to realizing a more accurate estimate of the optimal damping for friction dampers.

  11. Analysis of Anti-Wear Properties of CuO Nanoparticles as Friction Modifiers in Mineral Oil (460cSt Viscosity Using Pin-On-Disk Tribometer

    Directory of Open Access Journals (Sweden)

    S. Bhaumik

    2015-06-01

    Full Text Available The present work investigated the anti-wear properties of CuO nanoparticles based mineral oil using pin-on-disk apparatus. The pin material selected was EN 24(untreated as it is used in gear manufacturing. Commonly used graphite macro particles (wt.% and CuO nanoparticles(wt.% were used as additives. It had been observed that the additives based mineral oil samples exhibited superior antiwear properties than pure mineral oil. Both CuO nanoparticles (0.2 wt.% and graphite (0.2 wt.% based lubricant showed significant decrease in coefficient of friction and specific wear rate. There was a reduction in both coefficient of friction (28.5 % approx. and specific wear rate (70 % approx. in case of CuO nanolubricants and graphite based mineral oil as compared with the pure mineral oil.Flash-fire point, viscosity and viscosity index also increased with the increase in additive concentration. The surface characteristics of the pin were studied using Scanning Electron Microscope (SEM and surface roughness tester. The SEM images showed more rough surfaces in case of pure mineral oil samples as compared with graphite and CuO nanoparticles based samples. The surface roughness values of the pins in case of graphite (0.2 wt.% and CuO nano particles (0.2 wt.% based lubricant were much lesser than pure mineral oil. From the results predicted minimum 0.2 wt.% CuO nanoparticles were required to enhance the antiwear property of the lubricant. This work aimed in bringing a comparative experimental analysis using CuO nanoparticles and commonly used graphite macro particles as lubricant additives on various properties such as viscosity, flash point, fire point, surface roughness and anti-wear properties. Thus, the work would be useful in developing new nano lubricants with minimum additive concentration.

  12. Inter-tester and intra-tester reliability of ultrasound imaging measurements of abdominal muscles in adolescents with and without idiopathic scoliosis: a case-controlled study.

    Science.gov (United States)

    Yang, Hoe S; Yoo, Ji W; Lee, Bo A; Choi, Chang K; You, Joshua H

    2014-01-01

    The present study established inter-tester and intra-tester reliabilities of ultrasound imaging and diagnostically differentiated muscle imbalances in lateral abdominal muscle sizes between normal adolescents and adolescents with idiopathic scoliosis (AIS). Fifteen adolescents with AIS were age- and gender-matched with 15 normal adolescents. There was no significant difference between bilateral abdominal muscles in normal adolescents, but there was a significant difference between bilateral abdominal muscles in adolescents with AIS (Pabdominal muscle thickness is: (1) highly reliable between and within the testers; and (2) capable of distinguishing between subjects with and without pathological muscle morphology due to AIS.

  13. Control of friction at the nanoscale

    Science.gov (United States)

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

    2010-04-06

    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.

  14. Test strategies for industrial testers for converter controls equipment

    Science.gov (United States)

    Oleniuk, P.; Di Cosmo, M.; Kasampalis, V.; Nisbet, D.; Todd, B.; Uznański, S.

    2017-04-01

    Power converters and their controls electronics are key elements for the operation of the CERN accelerator complex, having a direct impact on its availability. To prevent early-life failures and provide means to verify electronics, a set of industrial testers is used throughout the converters controls electronics' life cycle. The roles of the testers are to validate mass production during the manufacturing phase and to provide means to diagnose and repair failed modules that are brought back from operation. In the converter controls electronics section of the power converters group in the technology department of CERN (TE/EPC/CCE), two main test platforms have been adopted: a PXI platform for mixed analogue-digital functional tests and a JTAG Boundary-Scan platform for digital interconnection and functional tests. Depending on the functionality of the device under test, the appropriate test platforms are chosen. This paper is a follow-up to results presented at the TWEPP 2015 conference, adding the boundary scan test platform and the first results from exploitation of the test system. This paper reports on the test software, hardware design and test strategy applied for a number of devices that has resulted in maximizing test coverage and minimizing test design effort.

  15. submitter Test strategies for industrial testers for converter controls equipment

    CERN Document Server

    Oleniuk, P; Kasampalis, V; Nisbet, D; Todd, B; Uznański, S

    2017-01-01

    Power converters and their controls electronics are key elements for the operation of the CERN accelerator complex, having a direct impact on its availability. To prevent early-life failures and provide means to verify electronics, a set of industrial testers is used throughout the converters controls electronics' life cycle. The roles of the testers are to validate mass production during the manufacturing phase and to provide means to diagnose and repair failed modules that are brought back from operation. In the converter controls electronics section of the power converters group in the technology department of CERN (TE/EPC/CCE), two main test platforms have been adopted: a PXI platform for mixed analogue-digital functional tests and a JTAG Boundary-Scan platform for digital interconnection and functional tests. Depending on the functionality of the device under test, the appropriate test platforms are chosen. This paper is a follow-up to results presented at the TWEPP 2015 conference, adding the boundary s...

  16. Friction in orthodontics

    Science.gov (United States)

    Prashant, P. S.; Nandan, Hemant; Gopalakrishnan, Meera

    2015-01-01

    Conventional wisdom suggests that resistance to sliding (RS) generated at the wire-bracket interface has a bearing on the force transmitted to the teeth. The relative importance of static and kinetic friction and also the effect of friction on anchorage has been a topic of debate. Lot of research work has been done to evaluate the various factors that affect friction and thus purportedly retards the rate of tooth movement. However, relevancy of these studies is questionable as the methodology used hardly simulates the oral conditions. Lately studies have concluded that more emphasis should be laid on binding and notching of archwires as these are considered to be the primary factors involved in retarding the tooth movement. This article reviews the various components involved in RS and the factors affecting friction. Further, research work should be carried out to provide cost effective alternatives aimed at reducing friction. PMID:26538873

  17. Cryogenic Active Magnetic Regenerator Test Apparatus

    Science.gov (United States)

    Tura, A.; Roszmann, J.; Dikeos, J.; Rowe, A.

    2006-04-01

    An AMR Test Apparatus (AMRTA) used in experiments near room-temperature required a number of modifications to allow for testing at cryogenic temperatures and with a 5 T magnetic field. The impacts of parasitic heat leaks, frictional heat generation, and eddy current heating in the AMRTA are analyzed. A low temperature gas circulation (LTGC) system to control the operating temperature was developed. The LTGC consists of a GM cryocooler coupled to a compressor and helium circuit which circulates fluid through a set of heat exchangers and flexible transfer lines connected to the AMRTA. Design features are discussed as is some initial test data.

  18. Improving friction performance of cast iron by laser shock peening

    Science.gov (United States)

    Feng, Xu; Zhou, Jianzhong; Huang, Shu; Sheng, Jie; Mei, Yufen; Zhou, Hongda

    2015-05-01

    According to different purpose, some high or low friction coefficient of the material surface is required. In this study, micro-dent texture was fabricated on cast iron specimens by a set of laser shock peening (LSP) experiments under different laser energy, with different patterns of micro dimples in terms of the depth over diameter. The mechanism of LSP was discussed and surface morphology of the micro dimples were investigated by utilizing a Keyence KS-1100 3D optical surface profilometer. The tests under the conditions of dry and lubricating sliding friction were accomplished on the UMT-2 apparatus. The performance of treated samples during friction and wear tests were characterized and analyzed. Based on theoretical analysis and experimental study, friction performance of textured and untextured samples were studied and compared. Morphological characteristics were observed by scanning electron microscope (SEM) and compared after friction tests under dry condition. The results showed that friction coefficient of textured samples were obvious changed than smooth samples. It can be seen that LSP is an effective way to improve the friction performance of cast iron by fabricating high quality micro dimples on its surface, no matter what kind of engineering application mentioned in this paper.

  19. Evaluation of ring surfaces with several coatings for friction,wear and scuffing life

    Institute of Scientific and Technical Information of China (English)

    Dae-Hyun CHO; Young-Ze LEE

    2009-01-01

    Friction and wear of the sliding components in an automobile cause an increase in both fuel consumption and emission. Many engine components involved with sliding contact are all susceptible to scuffing failure at some points during their operating period. Therefore, it is important to evaluate the effects of various surface coatings on the tribological characteristics of the piston ring and cylinder block surface of a diesel engine. Wear and scuffing tests were conducted using a friction and wear measurement of the piston ring and cylinder block in a low friction diesel engine. The frictional forces, wear amounts and cycles to scuffing in the boundary lubricated sliding condition were measured using the reciprocating wear tester. The tester used a piece of the cylinder block as the reciprocating specimen and a segment of the piston ring material as the fixed pin. Several coatings on the ring specimen were used, such as DLC, TiN, Cr-ceramic and TiAlN, in order to improve the tribological characteristics of the ring. The coefficients of friction were monitored during the tests, and the wear volumes of the piston ring surfaces with various coatings were compared. Test results show that the DLC coating exhibits better tribological properties than the other coatings. The graphite structure of this coating is responsible for the low friction and wear of the DLC film. The TiN and DLC coatings show better scuffing resistance than the other coatings. The TiN and Cr-ceramic coated rings show good wear resistance and high friction.

  20. LINE X TESTER ANALYSIS IN COMBINING ABILITIES ESTIMATION OF SUNFLOWER OIL CONTENT

    Directory of Open Access Journals (Sweden)

    Ivica Liović

    2012-12-01

    Full Text Available Results of line x tester analysis for 15 sunflower genotypes of the Agricultural Institute Osijek are presented in this paper. Three A lines (cms and three Rf testers with different oil content level (low, medium, high in all combinations (nine crosses were crossed in 2010. In 2011, the lines, testers and their crosses were sown in field trials at two locations (Karanac and Osijek. The oil content was determined after harvesting, whereas line x tester analysis was conducted based on the obtained results. Variance of lines and testers, which refers to the general combining ability (GCA was much higher than the variance of line x tester, related to specific combining ability (SCA. It showed on dominant role of the additive component of genetic variance in the inheritance of oil content. Statistically significant differences were not determined between the GCA and SCA effects. The highest values of GCA for oil content had line 2 (medium oil content and tester 6 (high oil content at both locations. The largest contribution for oil content had lines (57.81 and 51.28 % followed by testers (28.88 and 26.27 % and the lowest accounts for interaction (13.31 and 22.45 % at both locations (Karanac and Osijek.

  1. High inter-tester reliability of the new mobility score in patients with hip fracture

    DEFF Research Database (Denmark)

    Kristensen, M.T.; Bandholm, T.; Foss, N.B.;

    2008-01-01

    OBJECTIVE: To assess the inter-tester reliability of the New Mobility Score in patients with acute hip fracture. DESIGN: An inter-tester reliability study. SUBJECTS: Forty-eight consecutive patients with acute hip fracture at a median age of 84 (interquartile range, 76-89) years; 40 admitted from...

  2. Hand-Drawn Resistors and a Simple Tester Using a Light-Emitting Diode

    Science.gov (United States)

    Kamata, Masahiro; Abe, Mayumi

    2012-01-01

    A thick line drawn on a sheet of paper with a 6B pencil is electrically conductive and its resistance can be roughly estimated using a simple tester made of a light-emitting diode (LED) and a lithium coin-type cell. Using this hand-drawn resistor and the LED tester, we developed teaching materials that help students to understand how electrical…

  3. Hand-Drawn Resistors and a Simple Tester Using a Light-Emitting Diode

    Science.gov (United States)

    Kamata, Masahiro; Abe, Mayumi

    2012-01-01

    A thick line drawn on a sheet of paper with a 6B pencil is electrically conductive and its resistance can be roughly estimated using a simple tester made of a light-emitting diode (LED) and a lithium coin-type cell. Using this hand-drawn resistor and the LED tester, we developed teaching materials that help students to understand how electrical…

  4. Radiative Gasification Apparatus

    Data.gov (United States)

    Federal Laboratory Consortium — This apparatus, developed at EL, determines gasification rate (mass loss rate) of a horizontally oriented specimen exposed in a nitrogen environment to a controlled...

  5. DESIGN AND FABRICATION OF A LOW SPEED IMPACT TESTER

    Directory of Open Access Journals (Sweden)

    M. Navarrete

    2004-12-01

    Full Text Available The impact response of sandwich panels with an improved structure to increase their impact resistance isinvestigated. In order to compare the impact performance of sandwich structures, a specific and instrumenteddrop-weight impact tester was designed and developed. The experimental part of this work is an evaluation oncomposite sandwich panels behavior used in the manufacturing of the UNAM Electrobús chassis. Two differentsandwich structures are analyzed: the first type is a structure composed by a glass fiber-polyester matrix compositefacesheets and a polyethylene honeycomb core. The second one consists of facesheets made from a glass fiberepoxymatrix composite laminate and core formed by internal phenolic honeycomb structure. The first structurewas specifically designed to improve crashworthiness for transport applications. The main results of this study areevaluated from the absorbed energy performance of the sandwich structures subjected to a single impact, and thedevelopment of useful criteria for materials selection.

  6. Microprocessor tester for the treat upgrade reactor trip system

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-01-01

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

  7. Initial Development of an Electronic Testis Rigidity Tester

    Directory of Open Access Journals (Sweden)

    Petros Mirilas

    2011-01-01

    Full Text Available We aimed to develop our previously presented mechanical device, the Testis Rigidity Tester (TRT, into an electronic system (Electronic Testis Rigidity Tester, ETRT by applying tactile imaging, which has been used successfully with other solid organs. A measuring device, located at the front end of the ETRT incorporates a tactile sensor comprising an array of microsensors. By application of a predetermined deformation of 2 mm, increased pressure alters linearly the resistance of each microsensor, producing changes of voltage. These signals were amplified, filtered, and digitized, and then processed by an electronic collector system, which presented them as a color-filled contour plot of the area of the testis coming into contact with the sensor. Testis models of different rigidity served for initial evaluation of ETRT; their evacuated central spaces contained different, increasing glue masses. An independent method of rigidity measurement, using an electric weight scale and a micrometer, showed that the more the glue injected, the greater the force needed for a 2-mm deformation. In a preliminary test, a single sensor connected to a multimeter showed similar force measurement for the same deformation in these phantoms. For each of the testis models compressed in the same manner, the ETRT system offered a map of pressures, represented by a color scale within the contour plot of the contact area with the sensor. ETRT found certain differences in rigidity between models that had escaped detection by a blind observer. ETRT is easy to use and provides a color-coded “insight“ of the testis internal structure. After experimental testing, it could be valuable in intraoperative evaluation of testes, so that the surgeon can decide about orchectomy or orcheopexy.

  8. Dry friction and wear characteristics of MoSi2 against ahoy steels

    Institute of Scientific and Technical Information of China (English)

    CHEN Ping; ZHANG Hou'an; TANG Guoning; LI Songwen

    2005-01-01

    The dry friction and wear characteristics of three kinds of friction couples under different loads, MoSi2/45 tempered steel, MoSi2/45 quenched steel, and MoSi2/CrWMn steel, were investigated by using a friction and wear tester. SEM and X-ray diffraction were employed to analyze the microphotograph of the worn surface and the phase of worn pieces in order to reveal the wear mechanisms of MoSi2 material. The results show that MoSi2/CrWMn steel friction pair has good dry friction and wear properties under the load of 80 N, where the friction coefficient is 0.255 and the wear rate of MoSi2 is only 14.72 mg.km-1. But under the load of 150 N, it is MoSi2/45 tempered steel friction pair that has good tribological properties,MoSi2 under low loads is brittle fracture. With the increase of load, the main wear mechanism of MoSi2 against 45 quenched steel or CrWMn steel is adhesive wear. However, the wear mechanism of MoSi2 against 45 tempered steel is changed from oxidation-fatigue wear to adhesive wear.

  9. Iliotibial band friction syndrome.

    Science.gov (United States)

    Lavine, Ronald

    2010-07-20

    Published articles on iliotibial band friction syndrome have been reviewed. These articles cover the epidemiology, etiology, anatomy, pathology, prevention, and treatment of the condition. This article describes (1) the various etiological models that have been proposed to explain iliotibial band friction syndrome; (2) some of the imaging methods, research studies, and clinical experiences that support or call into question these various models; (3) commonly proposed treatment methods for iliotibial band friction syndrome; and (4) the rationale behind these methods and the clinical outcome studies that support their efficacy.

  10. Polymer friction Molecular Dynamics

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Samoilov, Vladimir N.; Persson, Bo N. J.

    We present molecular dynamics friction calculations for confined hydrocarbon solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: a) polymer sliding against a hard substrate, and b) polymer sliding on polymer. In the first setup the shear stresses are relatively...... independent of molecular length. For polymer sliding on polymer the friction is significantly larger, and dependent on the molecular chain length. In both cases, the shear stresses are proportional to the squeezing pressure and finite at zero load, indicating an adhesional contribution to the friction force....

  11. Friction behavior of 304 stainless steel of varying hardness lubricated with benzene and some benzyl structures

    Science.gov (United States)

    Buckley, D. H.

    1974-01-01

    The lubricating properties of some benzyl and benzene structures were determined by using 304 stainless steel surfaces strained to various hardness. Friction coefficients and wear track widths were measured with a Bowden-Leben type friction apparatus by using a pin-on-disk specimen configuration. Results obtained indicate that benzyl monosulfide, dibenzyl disulfide, and benzyl alcohol resulted in the lowest friction coefficients for 304 stainless steel, while benzyl ether provided the least surface protection and gave the highest friction. Strainhardening of the 304 stainless steel prior to sliding resulted in reduced friction in dry sliding. With benzyl monosulfide, dibenzyl disulfide, and benzyl alcohol changes in 304 stainless steel hardness had no effect upon friction behavior.

  12. Apparatus for Teaching Physics.

    Science.gov (United States)

    Gottlieb, Herbert H., Ed.

    1981-01-01

    Describes: (1) a variable inductor suitable for an inductance-capacitance bridge consisting of a fixed cylindrical solenoid and a moveable solenoid; (2) long-range apparatus for demonstrating falling bodies; and (3) an apparatus using two lasers to demonstrate ray optics. (SK)

  13. Aerosol distribution apparatus

    Science.gov (United States)

    Hanson, W.D.

    An apparatus for uniformly distributing an aerosol to a plurality of filters mounted in a plenum, wherein the aerosol and air are forced through a manifold system by means of a jet pump and released into the plenum through orifices in the manifold. The apparatus allows for the simultaneous aerosol-testing of all the filters in the plenum.

  14. Science 101: What Causes Friction?

    Science.gov (United States)

    Robertson, Bill

    2014-01-01

    Defining friction and asking what causes it might seem like a trivial question. Friction seems simple enough to understand. Friction is a force between surfaces that pushes against things that are moving or tending to move, and the rougher the surfaces, the greater the friction. Bill Robertson answers this by saying, "Well, not exactly".…

  15. Friction stir welding tool

    Science.gov (United States)

    Tolle; Charles R. , Clark; Denis E. , Barnes; Timothy A.

    2008-04-15

    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.

  16. Friction in volcanic environments

    Science.gov (United States)

    Kendrick, Jackie E.; Lavallée, Yan

    2016-04-01

    Volcanic landscapes are amongst the most dynamic on Earth and, as such, are particularly susceptible to failure and frictional processes. In rocks, damage accumulation is frequently accompanied by the release of seismic energy, which has been shown to accelerate in the approach to failure on both a field and laboratory scale. The point at which failure occurs is highly dependent upon strain-rate, which also dictates the slip-zone properties that pertain beyond failure, in scenarios such as sector collapse and pyroclastic flows as well as the ascent of viscous magma. High-velocity rotary shear (HVR) experiments have provided new opportunities to overcome the grand challenge of understanding faulting processes during volcanic phenomena. Work on granular ash material demonstrates that at ambient temperatures, ash gouge behaves according to Byerlee's rule at low slip velocities, but is slip-weakening, becoming increasingly lubricating as slip ensues. In absence of ash along a slip plane, rock-rock friction induces cataclasis and heating which, if sufficient, may induce melting (producing pseudotachylyte) and importantly, vesiculation. The viscosity of the melt, so generated, controls the subsequent lubrication or resistance to slip along the fault plane thanks to non-Newtonian suspension rheology. The shear-thinning behaviour and viscoelasticity of frictional melts yield a tendency for extremely unstable slip, and occurrence of frictional melt fragmentation. This velocity-dependence acts as an important feedback mechanism on the slip plane, in addition to the bulk composition, mineralogy and glass content of the magma, that all influence frictional behaviour. During sector collapse events and in pyroclastic density currents it is the frictional properties of the rocks and ash that, in-part, control the run-out distance and associated risk. In addition, friction plays an important role in the eruption of viscous magmas: In the conduit, the rheology of magma is integral

  17. Tester Board for testing mass-produced SMB modules for CMS Preshower

    Science.gov (United States)

    Velikzhanin, Y. S.; Chou, C. H.; Hsiung, Y. B.; Lee, Y. J.; Shiu, J. G.; Sun, C. D.; Wang, Y. Z.

    2007-09-01

    We have developed a Tester Board to test the electrical characteristics of the System Motherboard (SMB) for the CMS Preshower detector at CERN. The board is designed to test input resistances, output resistances, connections, interconnections and possible short- circuits of a module having up to 640 connector pins. The Tester Board is general-purpose in nature: it could be used to test any electronic module or cable by using dedicated cable sets. The module can detect a variety of problems not detected by either functional tests or the "flying probes" technique. The design, algorithms and results of using the Tester Board during mass production of CMS Preshower SMBs are presented.

  18. Tester Board for testing mass-produced SMB modules for CMS Preshower

    CERN Document Server

    Velikzhanin, Yu S; Hsiung, Y B; Lee, Y J; Shiu, J G; Sun, C D; Wang, Y Z

    2007-01-01

    We have developed a Tester Board to test the electrical characteristics of the System Motherboard (SMB) for the CMS Preshower detector at CERN. The board is designed to test input resistances, output resistances, connections, interconnections and possible short- circuits of a module having up to 640 connector pins. The Tester Board is general-purpose in nature: it could be used to test any electronic module or cable by using dedicated cable sets. The module can detect a variety of problems not detected by either functional tests or the "flying probes" technique. The design, algorithms and results of using the Tester Board during mass production of CMS Preshower SMBs are presented.

  19. Reflections on Friction in Quantum Mechanics

    Directory of Open Access Journals (Sweden)

    Yair Rezek

    2010-08-01

    Full Text Available Distinctly quantum friction effects of three types are surveyed: internalfriction, measurement-induced friction, and quantum-fluctuation-induced friction. We demonstrate that external driving will lead to quantum internal friction, and critique the measurement-based interpretation of friction. We conclude that in general systems will experience internal and external quantum friction over and beyond the classical frictional contributions.

  20. Friction properties of fluorinated compounds. Fusso kagobutsu no masatsu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Hironaka, S. (Tokyo Inst. of Technology, Tokyo (Japan). Faculty of Engineering); Sekiya, A. (National Inst. of Materials and Chemical Research, Tsukuba (Japan))

    1993-07-01

    In these years, fluorinated oils such as perfluoropolyalkyl ester and so on are developed as lubricating oil with better thermal stability as well as acid stability compared with hydrocarbon oil or ester. The results of the examination prosecuted by the present authors with a pendulum type friction tester on the friction properties in steel/steel system with perfluorooctanoic acid, n-C7F15COOH, and the synthesized compounds thereof like 1,1-dihydroperfluorooctanol, n-C7F15CH2OH, 1-hydroperfluorooctane-1,1-diol and n-C7F15CH(OH)2 as the additives clarify that they are respectively superior to the oleic acid and lauryl alcohol and expectable as the new oil agents. In the present study, 1,1-dihydroperfluorooctylamine, n-C7F15CH2NH2 are further synthesized, and the examination on the friction properties in the steel/steel system and steel/aluminium system reveals the effects thereof as the additives. 8 refs., 5 figs., 1 tab.

  1. Visual Scanning Hartmann Optical Tester (VSHOT) Uncertainty Analysis (Milestone Report)

    Energy Technology Data Exchange (ETDEWEB)

    Gray, A.; Lewandowski, A.; Wendelin, T.

    2010-10-01

    In 1997, an uncertainty analysis was conducted of the Video Scanning Hartmann Optical Tester (VSHOT). In 2010, we have completed a new analysis, based primarily on the geometric optics of the system, and it shows sensitivities to various design and operational parameters. We discuss sources of error with measuring devices, instrument calibrations, and operator measurements for a parabolic trough mirror panel test. These help to guide the operator in proper setup, and help end-users to understand the data they are provided. We include both the systematic (bias) and random (precision) errors for VSHOT testing and their contributions to the uncertainty. The contributing factors we considered in this study are: target tilt; target face to laser output distance; instrument vertical offset; laser output angle; distance between the tool and the test piece; camera calibration; and laser scanner. These contributing factors were applied to the calculated slope error, focal length, and test article tilt that are generated by the VSHOT data processing. Results show the estimated 2-sigma uncertainty in slope error for a parabolic trough line scan test to be +/-0.2 milliradians; uncertainty in the focal length is +/- 0.1 mm, and the uncertainty in test article tilt is +/- 0.04 milliradians.

  2. Screening of stabilized crosslinked polyethylene using a novel wear tester.

    Science.gov (United States)

    Hoffmann, M; Gonzalez-Mora, V; Chiesa, R; Cigada, A; Stroosnijder, M F

    2002-01-01

    A novel pin-on-disk type wear tester is described allowing a rapid screening of different types of polyethylene under both unidirectional and multidirectional sliding motion. The wear of four polyethylene materials sliding against a roughened CoCrMo alloy was evaluated: a non-irradiated UHMWPE, a UHMWPE irradiated with a dose of 25 kGy in air, and two types of crosslinked UHMWPE (100 kGy, air), which were subjected to a stabilization heat treatment in nitrogen at 155 degrees C for 72 hours (XLPE I) and in water at 130 degrees C for 72 hours (XLPE II), respectively.Under multidirectional sliding conditions both types of XLPE exhibited significantly less wear with respect to the 25 kGy irradiated UHMWPE and the non-irradiated UHMWPE, even under the rough counterface conditions applied. Under unidirectional sliding motion both types of XLPE exhibited the highest wear of all materials tested, because the orientation hardening effect acting under linear lubricated condition is less pronounced for crosslinked polyethylene.

  3. NMR logging apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, David O; Turner, Peter

    2014-05-27

    Technologies including NMR logging apparatus and methods are disclosed. Example NMR logging apparatus may include surface instrumentation and one or more downhole probes configured to fit within an earth borehole. The surface instrumentation may comprise a power amplifier, which may be coupled to the downhole probes via one or more transmission lines, and a controller configured to cause the power amplifier to generate a NMR activating pulse or sequence of pulses. Impedance matching means may be configured to match an output impedance of the power amplifier through a transmission line to a load impedance of a downhole probe. Methods may include deploying the various elements of disclosed NMR logging apparatus and using the apparatus to perform NMR measurements.

  4. Light shielding apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Richard Dean; Thom, Robert Anthony

    2017-10-10

    A light shielding apparatus for blocking light from reaching an electronic device, the light shielding apparatus including left and right support assemblies, a cross member, and an opaque shroud. The support assemblies each include primary support structure, a mounting element for removably connecting the apparatus to the electronic device, and a support member depending from the primary support structure for retaining the apparatus in an upright orientation. The cross member couples the left and right support assemblies together and spaces them apart according to the size and shape of the electronic device. The shroud may be removably and adjustably connectable to the left and right support assemblies and configured to take a cylindrical dome shape so as to form a central space covered from above. The opaque shroud prevents light from entering the central space and contacting sensitive elements of the electronic device.

  5. Thermal Acoustic Fatigue Apparatus

    Data.gov (United States)

    Federal Laboratory Consortium — The Thermal Acoustic Fatigue Apparatus (TAFA) is a progressive wave tube test facility that is used to test structures for dynamic response and sonic fatigue due to...

  6. NMR logging apparatus

    Science.gov (United States)

    Walsh, David O; Turner, Peter

    2014-05-27

    Technologies including NMR logging apparatus and methods are disclosed. Example NMR logging apparatus may include surface instrumentation and one or more downhole probes configured to fit within an earth borehole. The surface instrumentation may comprise a power amplifier, which may be coupled to the downhole probes via one or more transmission lines, and a controller configured to cause the power amplifier to generate a NMR activating pulse or sequence of pulses. Impedance matching means may be configured to match an output impedance of the power amplifier through a transmission line to a load impedance of a downhole probe. Methods may include deploying the various elements of disclosed NMR logging apparatus and using the apparatus to perform NMR measurements.

  7. Spin coating apparatus

    Science.gov (United States)

    Torczynski, John R.

    2000-01-01

    A spin coating apparatus requires less cleanroom air flow than prior spin coating apparatus to minimize cleanroom contamination. A shaped exhaust duct from the spin coater maintains process quality while requiring reduced cleanroom air flow. The exhaust duct can decrease in cross section as it extends from the wafer, minimizing eddy formation. The exhaust duct can conform to entrainment streamlines to minimize eddy formation and reduce interprocess contamination at minimal cleanroom air flow rates.

  8. Pulse shaping techniques for a high-g shock tester based on collision principle

    Science.gov (United States)

    Duan, Zhengyong; Tang, Chuansheng; Li, Yang; Han, Junliang; Wu, Guoxiong

    2016-09-01

    Pulse shaping techniques are discussed in this paper for the practicability of a developed high-g shock tester. The tester is based on collision principle where there is a one-level velocity amplifier. A theoretical and experimental study of pulse shaping techniques is presented. A model was built and theoretical formulae were deduced for the shock peak acceleration and its duration. Then theoretical analysis and some experiments were conducted. The test results verify the validity of theoretical model and show that the shock tester can generate the expected high-g shock pulses by integrated usage of different impact velocities and pulse shapers made from different materials. This is important in practical applications where the items under test can be shown to excite specific resonances at predetermined acceleration levels using the shock tester.

  9. Precision, comfort and mechanical performance of the Quadriso-tester, a quadriceps force measuring device

    NARCIS (Netherlands)

    Verkerke, GJ; Lemmink, KAPM; Slagers, AJ; Westhoff, MH; van Riet, GAJ; Rakhorst, G

    The mechanical performance, repeatability and comfort of the Quadriso-tester, which assesses isometric knee extensor muscle strength, were examined. Twenty healthy subjects and 20 patients treated for unilateral anterior ligamenta cruciata insufficiency were tested. Intra-rater repeatability was

  10. Bamboo Fibre-reinforced Semi-Metallic Brake Friction Materials for Automotive Applications

    Directory of Open Access Journals (Sweden)

    Talib R. J.

    2016-01-01

    Full Text Available Three friction material formulations composed of bamboo fiber along with binder, friction modifiers and filler have been prepared through powder metallurgy process. Sample F1 and F2 are composed of 10 wt. % of copper and barium, respectively, while the other ingredients in both formulations have the same wt. %. The wt. % of bamboo fiber in sample F3 is, however, increased by 100%, while the compositions of the other ingredients are proportionally decreased. The samples were examined for their porosity, hardness, and friction and wear properties using hot bath, Rockwell hardness tester, and CHASE friction dynamometer, respectively. The test results are compared with those of a commercial sample as the benchmark. Normal and hot frictions of all the three samples developed comply with the requirements specified by Automotive Manufacturer Equipment Companies Agency (AMECA. However, sample F3 which is composed of 20 wt. % of bamboo fiber does not comply with the minimum requirement of friction coefficient. Whereas, sample F2, which is composed of 10 wt. % of bamboo fiber and 10 wt. % of barium, has lower friction coefficient than the commercial sample, and has a sudden drop in friction coefficient at a temperature of 500°F. Out of three developed samples, sample F1, which is composed of 10 wt. % of bamboo fiber and 10 wt. % of copper, complies with all the requirements and has higher friction coefficient than the commercial sample, and has higher fade resistance. Thus, it could be postulated that bamboo fiber could be used as a reinforcing fiber with composition of 10 wt. %.

  11. Apparatus for drying sugar cubes

    NARCIS (Netherlands)

    Derckx, H.A.J.; Torringa, H.M.

    1999-01-01

    Device for drying sugar cubes containing a heating apparatus for heating and dehumidifying the sugar cubes, a conditioning apparatus for cooling off and possibly further dehumidifying the sugar cubes and a conveying apparatus for conveying the sugar cubes through the heating apparatus and the condit

  12. Apparatus for drying sugar cubes

    NARCIS (Netherlands)

    Derckx, H.A.J.; Torringa, H.M.

    1999-01-01

    Device for drying sugar cubes containing a heating apparatus for heating and dehumidifying the sugar cubes, a conditioning apparatus for cooling off and possibly further dehumidifying the sugar cubes and a conveying apparatus for conveying the sugar cubes through the heating apparatus and the

  13. Apparatus for drying sugar cubes

    NARCIS (Netherlands)

    Derckx, H.A.J.; Torringa, H.M.

    1999-01-01

    Device for drying sugar cubes containing a heating apparatus for heating and dehumidifying the sugar cubes, a conditioning apparatus for cooling off and possibly further dehumidifying the sugar cubes and a conveying apparatus for conveying the sugar cubes through the heating apparatus and the condit

  14. Wet Friction-Elements Boundary Friction Mechanism and Friction Coefficient Prediction

    Directory of Open Access Journals (Sweden)

    WANG Yanzhong

    2012-12-01

    Full Text Available The friction mechanism for the boundary friction course of friction elements engagement was explicitly expressed. The boundary friction model was built up by the surface topography. The model contained the effect of boundary film, adhesion, plough and lubrication. Based on the model, a coefficient for weakening plough for the lubrication was proposed. The modified model could fit for the working condition of wet friction elements. The friction coefficient as a function curve of rotating speed could be finally obtained by the data k and s/sm. The method provides a well interpretation of friction condition and friction coefficient prediction and the agreement between theoretical and experimental friction coefficients is reasonably good.

  15. Energy Balance of Friction and Friction Coefficient in Energetical Interpretation

    Directory of Open Access Journals (Sweden)

    S.V. Fedorov

    2015-09-01

    Full Text Available Sliding friction energy model is proposed. In this model, generalized mechanism of transformation and dissipation of energy under friction the model of elastic-plastic deformation and fracture contact volumes is considered. Energy model of the process of plastic deformation and destruction of solid bodies is based on the concept of ergodynamic of deformable bodies. Equations of energy balance of friction within the structural and energetic interpretation of deformation are proposed. The energy interpretation of the coefficient of friction is showed. From this position the friction coefficient is the most informative characteristic of the process. Experimental friction curves have been generalized. As a result of the energy analysis of friction, the energy diagram of the structural evolution of the friction surfaces is suggested.

  16. Fault Wear and Friction Evolution: Experimental Analysis

    Science.gov (United States)

    Boneh, Y.; Chang, J. C.; Lockner, D. A.; Reches, Z.

    2011-12-01

    Wear is an inevitable product of frictional sliding of brittle rocks as evidenced by the ubiquitous occurrence of fault gouge and slickenside striations. We present here experimental observations designed to demonstrate the relationship between wear and friction and their governing mechanisms. The experiments were conducted with a rotary shear apparatus on solid, ring-shaped rock samples that slipped for displacements up to tens of meters. Stresses, wear and temperature were continuously monitored. We analyzed 86 experiments of Kasota dolomite, Sierra White granite, Pennsylvania quartzite, Karoo gabbro, and Tennessee sandstone at slip velocities ranging from 0.002 to 0.97 m/s, and normal stress from 0.25 to 6.9 MPa. We conducted two types of runs: short slip experiments (slip distance mechanisms; and long slip experiments (slip distance > 3 m) designed to achieve mature wear conditions and to observe the evolution of wear and friction as the fault surfaces evolved. The experiments reveal three wear stages: initial, running-in, and steady-state. The initial stage is characterized by (1) discrete damage striations, the length of which is comparable to total slip , and local pits or plow features; (2) timing and magnitude of fault-normal dilation corresponds to transient changes of normal and shear stresses; and (3) surface roughness increasing with the applied normal stress. We interpret these observations as wear mechanisms of (a) plowing into the fresh rock surfaces; (b) asperity breakage; and (c) asperity climb. The running-in stage is characterized by (1) intense wear-rate over a critical wear distance of Rd = 0.3-2 m; (2) drop of friction coefficient over a weakening distance of Dc = 0.2-4 m; (3) Rd and Dc display positive, quasi-linear relation with each other. We interpret these observations as indicating the organizing of newly-created wear particles into a 'three-body' structure that acts to lubricate the fault (Reches & Lockner, 2010). The steady

  17. Sliding wear and friction behaviour of zircaloy-4 in water

    Science.gov (United States)

    Sharma, Garima; Limaye, P. K.; Jadhav, D. T.

    2009-11-01

    In water cooled nuclear reactors, the sliding of fuel bundles in fuel channel handling system can lead to severe wear and it is an important topic to study. In the present study, sliding wear behaviour of zircaloy-4 was investigated in water (pH ˜ 10.5) using ball-on-plate sliding wear tester. Sliding wear resistance zircaloy-4 against SS 316 was examined at room temperature. Sliding wear tests were carried out at different load and sliding frequencies. The coefficient of friction of zircaloy-4 was also measured during each tests and it was found to decrease slightly with the increase in applied load. The micro-mechanisms responsible for wear in zircaloy-4 were identified to be microcutting, micropitting and microcracking of deformed subsurface zones in water.

  18. Etiske utfordringer med non-invasive prenatale tester (NIPT

    Directory of Open Access Journals (Sweden)

    Bjørn Hofmann

    2014-05-01

    Full Text Available Analyser av cellefritt DNA fra foster i gravide kvinners blod gir nye muligheter innen fosterdiagnostikk: Testene er bedre enn eksisterende tester, de reduserer risikoen og er billigere. Flere land har tatt i bruk disse testene, og Helsedirektoratet i Norge har mottatt søknad om å ta i bruk en test som erstatter tidlig ultralyd og blodprøver. Likevel nøler norske myndigheter. Hvorfor gjør de det? Ett av svarene er at non-invasive prenatale tester fører med seg en rekke faglige og moralske spørsmål og gir flere grunnleggende etiske utfordringer. Denne artikkelen gjennomgår et bredt knippe av de utfordringene som NIPT reiser. Hensikten er å synliggjøre hvorfor NIPT påkaller etisk refleksjon og å bidra til en åpen debatt og en transparent beslutningsprosess. Artikkelen identifiserer fem sentrale og konkrete spørsmål for vurderingen av NIPT.Nøkkelord: non-invasiv prenatal diagnostikk, testing, fravalg, foster, blodprøve, ekspressivisme, statsliberalt dilemma, dilemma, abort, retten til ikke å viteEnglish summary: Ethical challenges with non-invasive prenatal tests (NIPTNon-invasive prenatal testing (NIPT performed with the use of massively parallel sequencing of cell-free DNA (cfDNA testing in maternal plasma gives extended possibilities in prenatal screening. The tests are claimed to be better than existing alternative tests, they reduce the risk, and it is claimed they are cheaper. They have been used in several countries since 2012, and the University Hospital of North Norway has applied to the Directorate of Health to replace first trimester ultrasound and plasma screening with NIPT. The Directorate of Health is reluctant to reply. Why is this? One of the answers may be that NIPT raises a series of professional and moral questions, and poses profound ethical challenges. This article reviews a series of the challenges with NIPT. The aim is to highlight why NIPT calls for ethical reflection and to contribute to an open debate

  19. Intelligent Flow Friction Estimation

    Directory of Open Access Journals (Sweden)

    Dejan Brkić

    2016-01-01

    Full Text Available Nowadays, the Colebrook equation is used as a mostly accepted relation for the calculation of fluid flow friction factor. However, the Colebrook equation is implicit with respect to the friction factor (λ. In the present study, a noniterative approach using Artificial Neural Network (ANN was developed to calculate the friction factor. To configure the ANN model, the input parameters of the Reynolds Number (Re and the relative roughness of pipe (ε/D were transformed to logarithmic scales. The 90,000 sets of data were fed to the ANN model involving three layers: input, hidden, and output layers with, 2, 50, and 1 neurons, respectively. This configuration was capable of predicting the values of friction factor in the Colebrook equation for any given values of the Reynolds number (Re and the relative roughness (ε/D ranging between 5000 and 108 and between 10−7 and 0.1, respectively. The proposed ANN demonstrates the relative error up to 0.07% which had the high accuracy compared with the vast majority of the precise explicit approximations of the Colebrook equation.

  20. Skin tribology: Science friction?

    NARCIS (Netherlands)

    Heide, van der E.; Zeng, X.; Masen, M.A.

    2013-01-01

    The application of tribological knowledge is not just restricted to optimizing mechanical and chemical engineering problems. In fact, effective solutions to friction and wear related questions can be found in our everyday life. An important part is related to skin tribology, as the human skin is fre

  1. Gravitomagnetic dynamical friction

    CERN Document Server

    Cashen, Benjamin; Kesden, Michael

    2016-01-01

    A supermassive black hole moving through a field of stars will gravitationally scatter the stars, inducing a backreaction force on the black hole known as dynamical friction. In Newtonian gravity, the axisymmetry of the system about the black hole's velocity $\\mathbf{v}$ implies that the dynamical friction must be anti-parallel to $\\mathbf{v}$. However, in general relativity the black hole's spin $\\mathbf{S}$ need not be parallel to $\\mathbf{v}$, breaking the axisymmetry of the system and generating a new component of dynamical friction similar to the Lorentz force $\\mathbf{F} = q\\mathbf{v} \\times \\mathbf{B}$ experienced by a particle with charge $q$ moving in a magnetic field $\\mathbf{B}$. We call this new force gravitomagnetic dynamical friction and calculate its magnitude for a spinning black hole moving through a field of stars with Maxwellian velocity dispersion $\\sigma$, assuming that both $v$ and $\\sigma$ are much less than the speed of light $c$. We use post-Newtonian equations of motion accurate to $...

  2. Friction and Wear Reduction of Eccentric Journal Bearing Made of Sn-Based Babbitt for Ore Cone Crusher

    Directory of Open Access Journals (Sweden)

    Auezhan Amanov

    2016-11-01

    Full Text Available An anti-friction Babbitt alloy-coated bearing made by a casting process is a journal bearing, which is used in an ore cone crusher eccentric. The main purpose of the Babbitt coated eccentric is to provide a low friction to support and guide a rotating shaft. Despite the fact that the Babbitt-coated eccentric offers a low friction coefficient and can be operated without a continuous supply of lubricant, it suffers from mining environments and short service life. In this study, an ultrasonic nanocrystalline surface modification (UNSM technique was used to further reduce the friction coefficient, to increase the wear resistance, and to extend the service life of the Sn-based Babbitt metal. The friction and wear behavior of the Sn-based Babbitt metal was investigated using a block-on-ring tester under both dry and oil-lubricated conditions. The results of the experiments revealed that the friction and wear behavior of Sn-based Babbitt metal could be improved by the application of the UNSM technique. The friction and wear mechanisms of the specimens were explained and discussed in terms of changes in surface properties—microstructure, surface hardness, surface roughness, etc.

  3. Friction Properties of Polished Cvd Diamond Films Sliding against Different Metals

    Science.gov (United States)

    Lin, Zichao; Sun, Fanghong; Shen, Bin

    2016-11-01

    Owing to their excellent mechanical and tribological properties, like the well-known extreme hardness, low coefficient of friction and high chemical inertness, chemical vapor deposition (CVD) diamond films have found applications as a hard coating for drawing dies. The surface roughness of the diamond films is one of the most important attributes to the drawing dies. In this paper, the effects of different surface roughnesses on the friction properties of diamond films have been experimentally studied. Diamond films were fabricated using hot filament CVD. The WC-Co (Co 6wt.%) drawing dies were used as substrates. A gas mixture of acetone and hydrogen gas was used as the feedstock gas. The CVD diamond films were polished using mechanical polishing. Polished diamond films with three different surface roughnesses, as well as the unpolished diamond film, were fabricated in order to study the tribological performance between the CVD diamond films and different metals with oil lubrication. The unpolished and polished CVD diamond films are characterized with scanning electron microscope (SEM), atomic force microscope (AFM), surface profilometer, Raman spectrum and X-ray diffraction (XRD). The friction examinations were carried out by using a ball-on-plate type reciprocating friction tester. Low carbide steel, stainless steel, copper and aluminum materials were used as counterpart balls. Based on this study, the results presented the friction coefficients between the polished CVD films and different metals. The friction tests demonstrate that the smooth surface finish of CVD diamond films is beneficial for reducing their friction coefficients. The diamond films exhibit low friction coefficients when slid against the stainless steel balls and low carbide steel ball, lower than that slid against copper ball and aluminum ball, attributed to the higher ductility of copper and aluminum causing larger amount of wear debris adhering to the sliding interface and higher adhesive

  4. Current measurement apparatus

    Science.gov (United States)

    Umans, Stephen D.

    2008-11-11

    Apparatus and methods are provided for a system for measurement of a current in a conductor such that the conductor current may be momentarily directed to a current measurement element in order to maintain proper current without significantly increasing an amount of power dissipation attributable to the current measurement element or adding resistance to assist in current measurement. The apparatus and methods described herein are useful in superconducting circuits where it is necessary to monitor current carried by the superconducting elements while minimizing the effects of power dissipation attributable to the current measurement element.

  5. Comparing Variability of Parameters between Roller Bed Brakes Testers and Dynamometric Platform of Ministry Of Transport Facilities

    Directory of Open Access Journals (Sweden)

    Senabre C

    2015-01-01

    Full Text Available This study gives a comparison between which parameters may vary when braking on two different Ministry of Transport (MOT brake testers, such as roller bed brake tester and dynamometric platform. A comparative study between both types of brake testers have been carried out by the mechanical engineering staffs at the mechanical laboratory at the Miguel Hernández University in Elche to determinate which parameters can vary the result of the test.

  6. High-speed friction and wear behaviors of bulk Ti3SiC2

    Institute of Scientific and Technical Information of China (English)

    HUANG Zhen-ying; ZHAI Hong-xiang; ZHOU Wei; ZHOU Yang; AI Ming-xin; ZHANG Zhi-li; LI Shi-bo

    2005-01-01

    High-speed friction and wear behaviors of bulk Ti3 SiC2 sliding drily against low carbon steel were investigated. Tests were carried out using a block-on-disk type tester with normal pressures ranging from 0.1 to 0.8 MPa and several sliding speeds from 20 to 60 m/s. The results show that, in the case of sliding speeds of 20 - 40 m/s, the friction coefficient exhibits a decreasing tendency with increasing the normal pressure after an increment in the smaller pressure range, and the worn quantity of Ti3SiC2 exhibits a nearly linear increase with increasing the normal pressure. However, when the sliding speed is up to 60 m/s, the friction coefficient exhibits a monotonous increase and the worn quantity exhibits a quadric increase with increasing the normal pressure. These speed-dependent and pressure-dependent behaviors are attributed to the antifriction effects of a frictionally generated oxide film covering the friction surface of Ti3SiC2, and a balance between the generating rate and the removing (wearing) rate of the film.

  7. Frictional Performance and Temperature Rise of a Mining Nonasbestos Brake Material during Emergency Braking

    Directory of Open Access Journals (Sweden)

    Jiusheng Bao

    2015-01-01

    Full Text Available By simulating emergency braking conditions of mine hoisters, tribological experiments of a mining nonasbestos brake material sliding on E355CC steel friction disc investigated a pad-on-disc friction tester. It is shown that, under combined influence of braking velocity and pressure, the lubricating film and micro-convex-apices on wear surface would have complex physicochemical reactions which make the instant friction coefficient rise gradually while the instant surface temperature rises first and then falls. With the antifriction effect from lubricating film and the desquamating of composite materials, the mean friction coefficient decreases first, then rises, and decreases again with the increasing of initial braking velocity. And with the existence of micro-convex-apices and variation from increment ratio of load and actual contacting area, it rises first and then falls with the increasing of braking pressure. However, the mean surface temperature rises obviously with the increasing of both initial braking velocity and braking pressure for growth of transformed kinetic energy. It is considered that the friction coefficient cannot be considered as a constant when designing brake devices for mine hoisters. And special attention should be paid to the serious influence of surface temperature on tribological performance of brake material during emergency braking.

  8. Preparation and frictional investigation of the two-components silanes deposited on alumina surface

    Energy Technology Data Exchange (ETDEWEB)

    Kośla, K.; Grobelny, J.; Cichomski, M., E-mail: mcichom@uni.lodz.pl

    2014-09-30

    Highlights: • The two-component silane films on the alumina surface were obtained by a combination of soft lithography and vapor phase deposition method. • The effectiveness of modification procedure was monitored by AFM topography images. • By using gas phase deposition method succeeded in obtaining a good reproduction of pattern. • Silane films with low surface free energy and coefficient of friction values were obtained. • The frictional performance in milli-Newton load range of one- and two-component films was investigated by microtribometry. - Abstract: Functionalization and pattering technique that permits two-component pattern-specific modification of alumina surface with silanes molecules are reported. The method relies on a two-component molecular system that simultaneously decreases coefficient of friction of the alumina surface and provides uniform chemical functionality suitable for further elaboration. Pattern/two-component modification is achieved via gas-phase deposition of the silanes using polydimethylsiloxane stamp. The frictional behaviors of the two-component films of the silane molecules with different chain length covalently absorbed on alumina surfaces, were characterized by the ball-disk (microtribometer) tester. The surfaces of the substrate modified by two-component molecular films were examined by atomic force microscopy (AFM). The measured tribological results showed that the mixing of the fluoroalkylsilane and alkylsilane enhance the lubrication and decrease the friction compared to the one-component thin films.

  9. Quantum tunneling with friction

    Science.gov (United States)

    Tokieda, M.; Hagino, K.

    2017-05-01

    Using the phenomenological quantum friction models introduced by P. Caldirola [Nuovo Cimento 18, 393 (1941), 10.1007/BF02960144] and E. Kanai [Prog. Theor. Phys. 3, 440 (1948), 10.1143/ptp/3.4.440], M. D. Kostin [J. Chem. Phys. 57, 3589 (1972), 10.1063/1.1678812], and K. Albrecht [Phys. Lett. B 56, 127 (1975), 10.1016/0370-2693(75)90283-X], we study quantum tunneling of a one-dimensional potential in the presence of energy dissipation. To this end, we calculate the tunneling probability using a time-dependent wave-packet method. The friction reduces the tunneling probability. We show that the three models provide similar penetrabilities to each other, among which the Caldirola-Kanai model requires the least numerical effort. We also discuss the effect of energy dissipation on quantum tunneling in terms of barrier distributions.

  10. Intra- and inter-tester reliability of sensibility testing in leprosy.

    Science.gov (United States)

    van Brakel, W H; Khawas, I B; Gurung, K S; Kets, C M; van Leerdam, M E; Drever, W

    1996-09-01

    We conducted an intra- and inter-tester agreement study of three sensory screening tests used in nerve function assessment of leprosy patients: the Semmes-Weinstein monofilament (SWM) test, moving 2-point discrimination (M2PD), and the pin prick test. The weighted kappa (Kw) statistic was used as the reliability coefficient. The SWM had intra-observer Kws ranging from 0.83 to 0.92 and inter-observer Kws ranging from 0.76 to 0.89. The M2PD had intra- and inter-tester Kws ranging from 0.75 to 0.82 and 0.54 to 0.82, respectively. Inter-tester agreement for the pin prick test ranged from 0.45 to 0.85. There was evidence that the main source of variability between testers was testing skill and experience. Among the experienced physiotechnicians there was no significant difference between intra- and inter-tester reliability. We conclude that reliability of the SWM test was very good, closely followed by the M2PD test. Reliability of the pin prick test was less good than that of the SWM and M2PD, making it less suitable for serial testing.

  11. communication method and apparatus

    DEFF Research Database (Denmark)

    2005-01-01

    The present invention relates to a non-lingual communication method and apparatus, wherein a physical or physiological signal consciously created by a first subject (1) is detected and converted into a transmitted output signal presented to a second subject (7) in order to communicate information...

  12. Mobile lighting apparatus

    Science.gov (United States)

    Roe, George Michael; Klebanoff, Leonard Elliott; Rea, Gerald W; Drake, Robert A; Johnson, Terry A; Wingert, Steven John; Damberger, Thomas A; Skradski, Thomas J; Radley, Christopher James; Oros, James M; Schuttinger, Paul G; Grupp, David J; Prey, Stephen Carl

    2013-05-14

    A mobile lighting apparatus includes a portable frame such as a moveable trailer or skid having a light tower thereon. The light tower is moveable from a stowed position to a deployed position. A hydrogen-powered fuel cell is located on the portable frame to provide electrical power to an array of the energy efficient lights located on the light tower.

  13. Friction in rail guns

    Science.gov (United States)

    Kay, P. K.

    1984-01-01

    The influence of friction is included in the present equations describing the performance of an inductively driven rail gun. These equations, which have their basis in an empirical formulation, are applied to results from two different experiments. Only an approximate physical description of the problem is attempted, in view of the complexity of details in the interaction among forces of this magnitude over time periods of the order of milisecs.

  14. Sliding Wear and Friction Behavior of Fuel Rod Material in Water and Dry State

    Science.gov (United States)

    Park, Jin Moo; Kim, Jae Hoon; Jeon, Kyeong Lak; Park, Jun Kyu

    In water cooled reactors, the friction between spacer grid and fuel rod can lead to severe wear and it is an important topic to study. In the present study, sliding wear behavior of zirconium alloy was investigated in water and dry state using the pin-on-disc sliding wear tester. Sliding wear resistance of zirconium alloy against heat treated inconel alloy was examined at room temperature. The parameters in this study were sliding velocity, axial load and sliding distance. The wear characteristics of zirconium alloy was evaluated by friction coefficient, specific wear rate and wear volume. The micro-mechanisms responsible for wear in zirconium alloy were identified to be micro-cutting, micro-pitting, delamination and micro-cracking of deformed surface zone.

  15. Effect of Lubricant Viscosity and Surface Roughness on Coefficient of Friction in Rolling Contact

    Directory of Open Access Journals (Sweden)

    S.G. Ghalme

    2013-12-01

    Full Text Available The main objective of this paper is to investigate the effect of surface roughness and lubricant viscosity on coefficient of friction in silicon nitride- steel rolling contact. Two samples of silicon nitride with two different values of surface roughness were tested against steel counter face. The test was performed on four ball tester in presence of lubricant with two different values of viscosity. Taguchi technique a methodology in design of experiment implemented to plan the experimentation and same is utilized to evaluate the interacting effect of surface roughness and lubricant viscosity. Analysis of experimental results presents a strong interaction between surface roughness and lubricant viscosity on coefficient of friction in rolling contact.

  16. Effect of amide type modified rapeseed oil as lubricating additive on friction and wear behavior of steel-steel and steel-aluminum alloy systems

    Institute of Scientific and Technical Information of China (English)

    FANG Jian-hua; CHEN Bo-shui; LIU Wei-min; DONG Lin; WANG Jiu

    2004-01-01

    A new type of environmentally friendly lube additive-amide type modified rapeseed oil was synthesized and characterized by infrared spectrum. Its effect on the friction and wear behavior of steel-steel and steel-aluminum alloy systems were investigated with a four-ball machine and an Optimol SRV friction and wear tester respectively.The morphographies of the worn surfaces were analyzed by means of scanning electron microscopy(SEM). The worn surfaces of the 2024Al alloy block were analyzed by means of X-ray photoelectron spectroscopy(XPS). The results show that the modified rapeseed oil as additives can obviously decrease the wear rate and friction coefficient of steel pair and steel-aluminum frictional pair. Its lubrication mechanism is inferred that a high strength complex protection films form on the worn surface of the Al alloy due to the adsorption or tribochemistry reaction of a long chain additive molecule and high reaction activity of N element.

  17. High Speed Friction Microscopy and Nanoscale Friction Coefficient Mapping

    OpenAIRE

    Bosse, James L.; Lee, Sungjun; Huey, Bryan D; Andersen, Andreas Sø; Sutherland, Duncan S

    2014-01-01

    As mechanical devices in the nano/micro length scale are increasingly employed, it is crucial to understand nanoscale friction and wear especially at technically relevant sliding velocities. Accordingly, a novel technique has been developed for Friction Coefficient Mapping (FCM), leveraging recent advances in high speed AFM. The technique efficiently acquires friction versus force curves based on a sequence of images at a single location, each with incrementally lower loads. As a result, true...

  18. Friction laws for lubricated nanocontacts

    Science.gov (United States)

    Buzio, R.; Boragno, C.; Valbusa, U.

    2006-09-01

    We have used friction force microscopy to probe friction laws for nanoasperities sliding on atomically flat substrates under controlled atmosphere and liquid environment, respectively. A power law relates friction force and normal load in dry air, whereas a linear relationship, i.e., Amontons' law, is observed for junctions fully immersed in model lubricants, namely, octamethylciclotetrasiloxane and squalane. Lubricated contacts display a remarkable friction reduction, with liquid and substrate specific friction coefficients. Comparison with molecular dynamics simulations suggests that load-bearing boundary layers at junction entrance cause the appearance of Amontons' law and impart atomic-scale character to the sliding process; continuum friction models are on the contrary of limited predictive power when applied to lubrication effects. An attempt is done to define general working conditions leading to the manifestation of nanoscale lubricity due to adsorbed boundary layers.

  19. Friction surfaced Stellite6 coatings

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2012-08-15

    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.

  20. Solid friction between soft filaments

    CERN Document Server

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

    2015-01-01

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

  1. Preferred states of the apparatus

    Indian Academy of Sciences (India)

    Anu Venugopalan

    2012-02-01

    A simple one-dimensional model for the system–apparatus interaction is analysed. The system is a spin-1/2 particle, and its position and momentum degrees constitute the apparatus. An analysis involving only unitary Schrödinger dynamics illustrates the nature of the correlations established in the system–apparatus entangled state. It is shown that even in the absence of any environment-induced decoherence, or any other measurement model, certain initial states of the apparatus – like localized Gaussian wavepackets – are preferred over others, in terms of measurementlike one-to-one correlations in the pure system–apparatus entangled state.

  2. Archimedes Force on Casimir Apparatus

    CERN Document Server

    Shevchenko, Vladimir

    2016-01-01

    We address a problem of Casimir apparatus in dense medium and weak gravitational field. The falling of the apparatus has to be governed by the equivalence principle, with proper account for contributions to the weight of the apparatus from its material part and from distorted quantum fields. We discuss general expression for the corresponding force in metric with cylindrical symmetry. By way of example we compute explicit expression for Archimedes force, acting on the Casimir apparatus of finite size, immersed into thermal bath of free scalar field. It is shown that besides universal term, proportional to the volume of the apparatus, there are non-universal quantum corrections, depending on the boundary conditions.

  3. Friction Characteristics of Nitrided Layers on AISI 430 Ferritic Stainless Steel Obtained by Various Nitriding Processes

    Directory of Open Access Journals (Sweden)

    Hakan AYDIN

    2013-03-01

    Full Text Available The influence of plasma, gas and salt-bath nitriding techniques on the friction coefficient of AISI 430 ferritic stainless steel was studied in this paper. Samples were plasma nitrided in 80 % N2 + 20 % H2 atmosphere at 450 °C and 520 °C for 8 h at a pressure of 2 mbar, gas nitrided in NH3 and CO2 atmosphere at 570 °C for 13 h and salt-bath nitrided in a cyanide-cyanate salt-bath at 570 °C for 1.5 h. Characterisation of nitrided layers on the ferritic stainless steel was carried out by means of microstructure, microhardness, surface roughness and friction coefficient measurements. Friction characteristics of the nitrided layers on the 430 steel were investigated using a ball-on-disc friction-wear tester with a WC-Co ball as the counter-body under dry sliding conditions. Analysis of wear tracks was carried out by scanning electron microscopy. Maximum hardness and maximum case depth were achieved on the plasma nitrided sample at 520 ºC for 8 h. The plasma and salt-bath nitriding techniques significantly decreased the average surface roughness of the 430 ferritic stainless steel. The friction test results showed that the salt-bath nitrided layer had better friction-reducing ability than the other nitrided layers under dry sliding conditions. Furthermore, the friction characteristic of the plasma nitrided layer at 520 ºC was better than that of the plasma nitrided layer at 450 °C.DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3819

  4. Micromechanical study of macroscopic friction and dissipation in idealised granular materials: the effect of interparticle friction

    NARCIS (Netherlands)

    Kruyt, N.P.; Rothenburg, L.; Gutkowski, Witold; Kowalewski, Tomasz A.

    2004-01-01

    Using Discrete Element Method (DEM) simulations with varying interparticle friction coefficient, the relation between interparticle friction coefficient and macroscopic continuum friction and dissipation is investigated. As expected, macroscopic friction and dilatancy increase with interparticle fri

  5. The yeast Golgi apparatus.

    Science.gov (United States)

    Suda, Yasuyuki; Nakano, Akihiko

    2012-04-01

    The Golgi apparatus is an organelle that has been extensively studied in the model eukaryote, yeast. Its morphology varies among yeast species; the Golgi exists as a system of dispersed cisternae in the case of the budding yeast Saccharomyces cerevisiae, whereas the Golgi cisternae in Pichia pastoris and Schizosaccharomyces pombe are organized into stacks. In spite of the different organization, the mechanism of trafficking through the Golgi apparatus is believed to be similar, involving cisternal maturation, in which the resident Golgi proteins are transported backwards while secretory cargo proteins can stay in the cisternae. Questions remain regarding the organization of the yeast Golgi, the regulatory mechanisms that underlie cisternal maturation of the Golgi and transport machinery of cargo proteins through this organelle. Studies using different yeast species have provided hints to these mechanisms.

  6. The radon EDM apparatus

    Science.gov (United States)

    Tardiff, E. R.; Rand, E. T.; Ball, G. C.; Chupp, T. E.; Garnsworthy, A. B.; Garrett, P.; Hayden, M. E.; Kierans, C. A.; Lorenzon, W.; Pearson, M. R.; Schaub, C.; Svensson, C. E.

    2014-01-01

    The observation of a permanent electric dipole moment (EDM) at current experimentally accessible levels would provide clear evidence of physics beyond the Standard Model. EDMs violate CP symmetry, making them a possible route to explaining the size of the observed baryon asymmetry in the universe. The Radon EDM Experiment aims to search for an EDM in radon isotopes whose sensitivity to CP-odd interactions is enhanced by octupole-deformed nuclei. A prototype apparatus currently installed in the ISAC hall at TRIUMF includes a gas handling system to move radon from a collection foil to a measurement cell and auxiliary equipment for polarization diagnostics and validation. The features and capabilities of the apparatus are described and an overview of the experimental design for a gamma-ray-anisotropy based EDM measurement is provided.

  7. Friction and wear calculation methods

    CERN Document Server

    Kragelsky, I V; Kombalov, V S

    1981-01-01

    Friction and Wear: Calculation Methods provides an introduction to the main theories of a new branch of mechanics known as """"contact interaction of solids in relative motion."""" This branch is closely bound up with other sciences, especially physics and chemistry. The book analyzes the nature of friction and wear, and some theoretical relationships that link the characteristics of the processes and the properties of the contacting bodies essential for practical application of the theories in calculating friction forces and wear values. The effect of the environment on friction and wear is a

  8. Heat exchange apparatus

    Science.gov (United States)

    Degtiarenko, Pavel V.

    2003-08-12

    A heat exchange apparatus comprising a coolant conduit or heat sink having attached to its surface a first radial array of spaced-apart parallel plate fins or needles and a second radial array of spaced-apart parallel plate fins or needles thermally coupled to a body to be cooled and meshed with, but not contacting the first radial array of spaced-apart parallel plate fins or needles.

  9. Pyrolysis process and apparatus

    Science.gov (United States)

    Lee, Chang-Kuei

    1983-01-01

    This invention discloses a process and apparatus for pyrolyzing particulate coal by heating with a particulate solid heating media in a transport reactor. The invention tends to dampen fluctuations in the flow of heating media upstream of the pyrolysis zone, and by so doing forms a substantially continuous and substantially uniform annular column of heating media flowing downwardly along the inside diameter of the reactor. The invention is particularly useful for bituminous or agglomerative type coals.

  10. Friction or Closure

    DEFF Research Database (Denmark)

    Lundahl, Mikela

    2014-01-01

    . The anthropologist Anna Tsing has developed the concept-metaphor friction as a way to discuss the energy created when various actors narrate “the same” event(s) in different ways, and see the other participants’ accounts as fantasies or even fabrications. I will use my position as researcher and my relations...... is Stone Town in Zanzibar and the de-velopment and dissolution going on under the shadow of the UNESCO World Heritage flag; a growing tourism; a global and local increase in islamisation; and the political tension within the Tanzanian union. My main focus is narratives of the identity of Zanzibar since...

  11. Design of new frictional testing machine for shallow fault materials

    Science.gov (United States)

    Tadai, O.; Tanikawa, W.; Hirose, T.; Sakaguchi, M.; Lin, W.

    2009-12-01

    Subduction thrust faults at shallow depth mainly consist of granular and clay-rich materials which strengths are influenced by the presence of pore water. Dilatation and pore pressure generation of fault zones by the dynamic friction will increase the volumetric water content in fault zone, which can assist the fault weakening by acoustic fluidization or hydrodynamic lubrication mechanism. Therefore the evaluation of rheology for clay minerals rich in pore water is critical for understanding of seismic behaviors at shallow depth. Here, we introduce a new testing apparatus for the purpose of accurate evaluation of friction behavior for incohesive fault rock materials. Our machine can shear granular materials up to 80 mm of outer diameter and maximum thickness of 40 mm. The capacities of axial load, torque, and motor are 100kN, 500Nm and 30kW, respectively, and pore pressure is increased up to 50 MPa. Maximum rotation speed is 660 rpm, which is equivalent to 1 m/s of the average slip velocity when sample diameter is 60 mm. We can monitor the dynamic changes of pore pressure and temperature at sliding surface during the friction tests. We can also control the pore pressure, axial load, pore pressure and temperature independently. All parameters can be held at targeted values and be generated at constant incremental velocity. We can control the rotation more sensitively to program the complicated rotation history that slip velocity and acceleration change during the rotation. We used powdered smectite and illite in our friction tests. We measured normal stress dependence on shear stress at normal stress up to 25 MPa with a constant rotation speed from 0.01 to 1 rpm. Normal stress is proportional to shear stress for dry clay minerals, and the friction coefficients are from 0.3 to 0.5. On the other hand, very low friction is observed in clay minerals saturated by water, and shear strength is nearly constant at various normal stresses. Our results suggest that clay

  12. Friction analysis of kinetic schemes : the friction coefficient

    NARCIS (Netherlands)

    Lolkema, Juke S.

    1995-01-01

    Friction analysis is proposed as the application of general control analysis to single enzymes to describe the control of elementary kinetic steps on the overall catalytic rate. For each transition, a friction coefficient is defined that measures the sensitivity of the turnover rate to the free ener

  13. FRICTION ANALYSIS OF KINETIC SCHEMES - THE FRICTION COEFFICIENT

    NARCIS (Netherlands)

    LOLKEMA, JS

    1995-01-01

    Friction analysis is proposed as the application of general control analysis to single enzymes to describe the control of elementary kinetic steps on the overall catalytic rate. For each transition, a friction coefficient is defined that measures the sensitivity of the turnover rate to the free ener

  14. Friction analysis of kinetic schemes : the friction coefficient

    NARCIS (Netherlands)

    Lolkema, Juke S.

    1995-01-01

    Friction analysis is proposed as the application of general control analysis to single enzymes to describe the control of elementary kinetic steps on the overall catalytic rate. For each transition, a friction coefficient is defined that measures the sensitivity of the turnover rate to the free ener

  15. On the Friction and Wear Behaviors of Dental Machinable Porcelain

    Institute of Scientific and Technical Information of China (English)

    YU Hai-yang; ZHOU Zhong-rong; CAI Zhen-Bing

    2004-01-01

    In order to well design tribosystems of dental CAD-CAM restorations, an understanding of the tribological mechanisms of dental machinable porcelain are essential. The friction and wear behavior of new generation industrially prefabricated Cerec Vitablocs Mark Ⅱ against uniform Si3N4 ball has been performed using a small amplitude reciprocating apparatus under simulating oral conditions. The loads of 10-40 N, reciprocating amplitudes of 100-500 μm, frequencies of 1-4 Hz and two lubrications (no / artificial saliva lubrication) were selected. Tests lasting up to 10 000 cycles were conducted. The results show that Cerec Vitablocs Mark Ⅱ record a friction coefficient of 0.55-0.84. Artificial saliva plays a lubricant effect during wear process. Among three parameters of the test on friction coefficient and wear depth of dental machinable porcelains, the load effect is prominent. Abrasive wear is the main wear mechanism, but brittle cracks and delamination are more popular especially under unlubricated friction.

  16. On the Friction and Wear Behaviors of Dental Machinable Porcelain

    Institute of Scientific and Technical Information of China (English)

    YUHai-yang; ZHOUZhong-rong; CAIZhen-Bing

    2004-01-01

    In order to well design tribosystems of dental CAD-CAM restorations, an understanding of the tribological mechanisms of dental machinable porcelain are essential. The friction and wear behavior of new generation industrially prefabricated Cerec Vitablocs Mark II against uniform Si3N4ball has been performed using a small amplitude reciprocating apparatus under simulating oral conditions. The loads of 10-40N, reciprocating amplitudes of 100-500μm, frequencies of 1-4Hz and two lubrications (no / artificial saliva lubrication) were selected. Tests lasting up to 10 000 cycles were conducted. The results show that Cerec Vitablocs Mark Ⅱ record a friction coefficient of 0.55-0.84. Artificial saliva plays a lubricant effect during wear process. Among three parameters of the test on friction coefficient and wear depth of dental machinable porcelains, the load effect is prominent. Abrasive wear is the main wear mechanism, but brittle cracks and delamination are more popular especially under unlubricated friction.

  17. Friction, wear, and thermal stability studies of some organotin and organosilicon compounds

    Science.gov (United States)

    Jones, W. R., Jr.

    1973-01-01

    Thermal decomposition temperatures were determined for a number of organotin and organosilicon compounds. A ball-on-disk sliding friction apparatus was used to determine the friction and wear characteristics of two representative compounds, (1) 3-tri-n-butylstannyl (diphenyl) and (2) 3-tri-n-butylsilyl (diphenyl). Friction and wear test conditions included a 1-kg load, 25 to 225 C disk temperatures, and a dry air atmosphere. The tin and silicon compounds yielded friction and wear results either lower than or similar to those obtained with a polyphenyl ether and a C-ether. The maximum thermal decomposition temperatures obtained in the silicon and tin series were 358 and 297 C, respectively. Increasing the steric hindrance around the silicon or tin atoms increased the thermal stability. Future work with these compounds will emphasize their use as antiwear additives rather than base fluids.

  18. Slow frictional waves

    Science.gov (United States)

    Viswanathan, Koushik; Sundaram, Narayan; Chandrasekar, Srinivasan

    Stick-slip, manifest as intermittent tangential motion between two dry solid surfaces, is a friction instability that governs diverse phenomena from automobile brake squeals to earthquakes. We show, using high-speed in situ imaging of an adhesive polymer interface, that low velocity stick-slip is fundamentally of three kinds, corresponding to passage of three different surface waves -- separation pulses, slip pulses and the well-known Schallamach waves. These waves, traveling much slower than elastic waves, have clear distinguishing properties. Separation pulses and Schallamach waves involve local interface separation, and propagate in opposite directions while slip pulses are characterized by a sharp stress front and do not display any interface detachment. A change in the stick-slip mode from separation to slip pulse is effected simply by increasing the normal force. Together, these three waves constitute all possible stick-slip modes in adhesive friction and are shown to have direct analogues in muscular locomotory waves in soft bodied invertebrates. A theory for slow wave propagation is also presented which is capable of explaining the attendant interface displacements, velocities and stresses.

  19. Friction Stir Welding

    Science.gov (United States)

    Nunes, Arthur C., Jr.

    2008-01-01

    Friction stir welding (FSW) is a solid state welding process invented in 1991 at The Welding Institute in the United Kingdom. A weld is made in the FSW process by translating a rotating pin along a weld seam so as to stir the sides of the seam together. FSW avoids deleterious effects inherent in melting and promises to be an important welding process for any industries where welds of optimal quality are demanded. This article provides an introduction to the FSW process. The chief concern is the physical effect of the tool on the weld metal: how weld seam bonding takes place, what kind of weld structure is generated, potential problems, possible defects for example, and implications for process parameters and tool design. Weld properties are determined by structure, and the structure of friction stir welds is determined by the weld metal flow field in the vicinity of the weld tool. Metal flow in the vicinity of the weld tool is explained through a simple kinematic flow model that decomposes the flow field into three basic component flows: a uniform translation, a rotating solid cylinder, and a ring vortex encircling the tool. The flow components, superposed to construct the flow model, can be related to particular aspects of weld process parameters and tool design; they provide a bridge to an understanding of a complex-at-first-glance weld structure. Torques and forces are also discussed. Some simple mathematical models of structural aspects, torques, and forces are included.

  20. 16 CFR Figure 3 to Subpart A of... - Flooring Radiant Tester Schematic Side Elevation

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Flooring Radiant Tester Schematic Side Elevation 3 Figure 3 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION The Standard Pt...

  1. An innovative tester system for measuring mechanical property of foundry molding sand

    Directory of Open Access Journals (Sweden)

    Zuxi XIE

    2004-11-01

    Full Text Available A new intelligent tester system for measuring multiple mechanical properties of foundry molding sand is introduced and has been patented for the invention in China. The testing process can be simutaneosly controlled wth a build-in chip microcomputer communicating with a PC through a serial port. The testing system pplies dynamic testing technology. During the measurement for compression, relaxation, shearing and tensile processes of sand specimens, the corresponding characteristic curves and eight mechanical property parameters can be obtained in a short time, simply by consecutively testing on four sand specimens. The properties and parameters to be measurable by the tester include compressive strength, elastic modulus, plastic deformation threshold, springback potential, shear strength, shear deformation limit, toughness and tensile strength. These properties and parameters for sand specimens can be defined as the corresponding characteristic curves with precise physical meanings, carried out by the tester. Two of them, namely plastic deformation threshold and springback potential, as well as their testing methods, have been invented for the first time. The testing system applying advanced data measurement technology as well as performing excellent functions is an important breakthrough and creativity in foundry molding sand property testing field. The parameters acquired by the testing system are stable, accurate and reliable. The test data can be instantly diaplayed or printed out or stored in the PC. As evidence, many experimental data obtained by the tester practically from bth laboratory and foundry floor tests indicate that the testr system can be widely applied in foundry industry.

  2. Investigation of Physical and Chemical Delay Periods of Different Fuels in the Ignition Quality Tester (IQT)

    Science.gov (United States)

    2012-11-03

    F-T SPK Fischer-Tropsch Synthetic Paraffinic Kerosene HMN Hepta- methyl -nonane ID Ignition Delay IQT Ignition Quality Tester JP-8 Jet...opening pressure is 10.3±0.34 MPa. By definition, normal cetane (hexadecane C16H34) is assigned a CN of 100, whereas hepta- methyl -nonane (HMN) is

  3. Direct Labeling, Tester Expectancy and Delay Maintenance Behavior in Scottish Preschool Children.

    Science.gov (United States)

    Ritchie, Fiona K.; Toner, Ignatius J.

    1984-01-01

    Investigates the influence on Scottish preschool children's self-control of labels regarding patience given directly to the children themselves, and of the expectations regarding the children's patience provided to adult testers. Childrens self-control was assessed in a task in which each child's possession of accumulating candy rewards was made…

  4. Testers for combining ability and selection of papaya hybrids resistant to fungal diseases

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Pessanha da Silva Terra

    2011-01-01

    Full Text Available Genetic resistance represents a sustainable alternative to disease control in papaya crop. The purpose of this studywas to evaluate the use of testers to estimate combining ability and select hybrids resistant to black spot, phoma spot and chocolatespot. The experiment was conducted in a randomized block design with two replications and 20 plants per plot. The severity ofphoma spot and black spot on leaves and the lesion area of black spot and chocolate spot on fruits were evaluated in twoseasons. The combining ability of the following crosses is negative for all traits: tester ‘JS 12’ with ‘Sunrise Solo’ and ‘Kaphoro SoloPV’; tester ‘Americano’ with ‘Caliman M5’, ‘Sunrise Solo’, ’Baixinho de Santa Amália’ and ‘Waimanalo’; and tester ‘Maradol’with ‘Caliman G’, ‘Caliman AM’ and ‘Sunrise Solo PT’. These results may be useful in breeding for disease resistance byhybridization.

  5. Corrosion effects on friction factors

    Energy Technology Data Exchange (ETDEWEB)

    Magleby, H.L.; Shaffer, S.J.

    1996-03-01

    This paper presents the results of NRC-sponsored material specimen tests that were performed to determine if corrosion increases the friction factors of sliding surfaces of motor-operated gate valves, which could require higher forces to close and open safety-related valves when subjected to their design basis differential pressures. Friction tests were performed with uncorroded specimens and specimens subjected to accelerated corrosion. Preliminary tests at ambient conditions showed that corrosion increased the friction factors, indicating the need for additional tests duplicating valve operating parameters at hot conditions. The additional tests showed friction factors of corroded specimens were 0.1 to 0.2 higher than for uncorroded specimens, and that the friction factors of the corroded specimens were not very dependent on contact stress or corrosion film thickness. The measured values of friction factors for the three corrosion films tested (simulating three operating times) were in the range of 0.3 to 0.4. The friction factor for even the shortest simulated operating time was essentially the same as the others, indicating that the friction factors appear to reach a plateau and that the plateau is reached quickly.

  6. Elastic model of dry friction

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-09-15

    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.

  7. Influence of roughness parameters on coefficient of friction under lubricated conditions

    Indian Academy of Sciences (India)

    Pradeep L Menezes; Kishore; Satish V Kailas

    2008-06-01

    Surface texture and thus roughness parameters influence coefficient of friction during sliding. In the present investigation, four kinds of surface textures with varying roughness were attained on the steel plate surfaces. The surface textures of the steel plates were characterized in terms of roughness parameter using optical profilometer. Then the pins made of various materials, such as Al-4Mg alloy, Al-8Mg alloy, Cu, Pb, Al, Mg, Zn and Sn were slid against the prepared steel plates using an inclined pin-on-plate sliding tester under lubricated conditions. It was observed that the surface roughness parameter, namely, $R_{a}$, for different textured surfaces was comparable to one another although they were prepared by different machining techniques. It was also observed that for a given kind of surface texture the coefficient of friction did not vary with $R_a$. However, the coefficient of friction changes considerably with surface textures for similar $R_a$ values for all the materials investigated. Thus, attempts were made to study other surface roughness parameters of the steel plates and correlate them with coefficient of friction. It was observed that among the surface roughness parameters, the mean slope of the profile, $Del\\ a(\\Delta _a)$, was found to explain the variations best.

  8. Dry Friction and Wear Characteristics of Rare-Earth/MoSi2 Composite

    Institute of Scientific and Technical Information of China (English)

    张厚安; 龙春光; 陈平; 刘心宇

    2003-01-01

    The dry friction and wear characteristics of rare earth/MoSi2 composite against 45 steel under different loads were investigated by using an M-200 type friction and wear tester. SEM and XRD were used to analyze the morphology of the friction surface and the phase of worn piece in order to reveal the wear mechanism of rare-earth/MoSi2 composite. Results show that the relationships of friction coefficient, μ, or wear rate, W, of MoSi2 and RE/MoSi2 composite to loads, p, can be fitted well with the following function: μ(or W)= a+bp+cp2+dp3+ep4, where a, b, c, d and e are fitting constants depending on materials and confidence. MoSi2 and rare-earth/MoSi2 composite have excellent wear resistance. When load is in the range of 80~120 N, the wear rate of RE/MoSi2 composite is lower than that of MoSi2 material by about 65%. The main wear mechanism of rare-earth/MoSi2 composite is adhesive wear.

  9. Friction in surface micromachined microengines

    Energy Technology Data Exchange (ETDEWEB)

    Miller, S.L.; Sniegowski, J.J.; LaVigne, G.; McWhorter, P.J.

    1996-03-01

    Understanding the frictional properties of advanced Micro-Electro- Mechanical Systems (MEMS) is essential in order to develop optimized designs and fabrication processes, as well as to qualify devices for commercial applications. We develop and demonstrate a method to experimentally measure the forces associated with sliding friction of devices rotating on a hub. The method is demonstrated on the rotating output gear of the microengine recently developed at Sandia National Laboratories. In-situ measurements of an engine running at 18300 rpm give a coefficient of friction of 0.5 for radial (normal) forces less than 4 {mu}N. For larger forces the effective coefficient of friction abruptly increases, suggesting a fundamental change in the basic nature of the interaction between the gear and hub. The experimental approach we have developed to measure the frictional forces associated with the microengine is generically applicable to other MEMS devices.

  10. Tactile friction of topical formulations.

    Science.gov (United States)

    Skedung, L; Buraczewska-Norin, I; Dawood, N; Rutland, M W; Ringstad, L

    2016-02-01

    The tactile perception is essential for all types of topical formulations (cosmetic, pharmaceutical, medical device) and the possibility to predict the sensorial response by using instrumental methods instead of sensory testing would save time and cost at an early stage product development. Here, we report on an instrumental evaluation method using tactile friction measurements to estimate perceptual attributes of topical formulations. Friction was measured between an index finger and an artificial skin substrate after application of formulations using a force sensor. Both model formulations of liquid crystalline phase structures with significantly different tactile properties, as well as commercial pharmaceutical moisturizing creams being more tactile-similar, were investigated. Friction coefficients were calculated as the ratio of the friction force to the applied load. The structures of the model formulations and phase transitions as a result of water evaporation were identified using optical microscopy. The friction device could distinguish friction coefficients between the phase structures, as well as the commercial creams after spreading and absorption into the substrate. In addition, phase transitions resulting in alterations in the feel of the formulations could be detected. A correlation was established between skin hydration and friction coefficient, where hydrated skin gave rise to higher friction. Also a link between skin smoothening and finger friction was established for the commercial moisturizing creams, although further investigations are needed to analyse this and correlations with other sensorial attributes in more detail. The present investigation shows that tactile friction measurements have potential as an alternative or complement in the evaluation of perception of topical formulations. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  11. Thermal stir welding apparatus

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2011-01-01

    A welding method and apparatus are provided for forming a weld joint between first and second elements of a workpiece. The method includes heating the first and second elements to form an interface of material in a plasticized or melted state interface between the elements. The interface material is then allowed to cool to a plasticized state if previously in a melted state. The interface material, while in the plasticized state, is then mixed, for example, using a grinding/extruding process, to remove any dendritic-type weld microstructures introduced into the interface material during the heating process.

  12. Solder dross removal apparatus

    Science.gov (United States)

    Webb, Winston S. (Inventor)

    1992-01-01

    An automatic dross removal apparatus (10) is disclosed for removing dross from the surface of a solder bath (22) in an automated electric component handling system. A rotatable wiper blade (14) is positioned adjacent the solder bath (22) which skims the dross off of the surface prior to the dipping of a robot conveyed component into the bath. An electronic control circuit (34) causes a motor (32) to rotate the wiper arm (14) one full rotational cycle each time a pulse is received from a robot controller (44) as a component approaches the solder bath (22).

  13. Temperature dependence of ice-on-rock friction at realistic glacier conditions.

    Science.gov (United States)

    McCarthy, C; Savage, H; Nettles, M

    2017-02-13

    Using a new biaxial friction apparatus, we conducted experiments of ice-on-rock friction in order to better understand basal sliding of glaciers and ice streams. A series of velocity-stepping and slide-hold-slide tests were conducted to measure friction and healing at temperatures between -20°C and melting. Experimental conditions in this study are comparable to subglacial temperatures, sliding rates and effective pressures of Antarctic ice streams and other glaciers, with load-point velocities ranging from 0.5 to 100 µm s(-1) and normal stress σn = 100 kPa. In this range of conditions, temperature dependences of both steady-state friction and frictional healing are considerable. The friction increases linearly with decreasing temperature (temperature weakening) from μ = 0.52 at -20°C to μ = 0.02 at melting. Frictional healing increases and velocity dependence shifts from velocity-strengthening to velocity-weakening behaviour with decreasing temperature. Our results indicate that the strength and stability of glaciers and ice streams may change considerably over the range of temperatures typically found at the ice-bed interface.This article is part of the themed issue 'Microdynamics of ice'.

  14. Mechanical and topographic evaluation of esthetic brackets and its relation to frictional resistance

    Directory of Open Access Journals (Sweden)

    Vikram Pai

    2013-01-01

    Full Text Available Introduction: The purpose of this in-vitro study was to evaluate the frictional characteristics of conventional ceramic versus metal insert ceramic brackets in combination with stainless steel and Teflon-coated stainless steel archwires. Materials and Methods: Twenty brackets each, of ceramic and metal insert ceramic Maxillary canine preadjusted edgewise brackets 0.022 × 0.028 in slot and 20 archwires, each of stainless steel and Teflon-coated stainless steel (0.019 × 0.025 in were tested for frictional resistance. Friction was evaluated in a simulated Tidy′s design apparatus on universal testing machine. The kinetic friction data were analyzed using Student′s ′t′ test. The effects of surface characteristics on frictional resistance were qualitatively assessed using scanning electron microscope. Results: Metal insert ceramic brackets generated significantly lower kinetic frictional resistance than the conventional ceramic brackets with Teflon-coated stainless steel archwires (P < 0.001 as well as stainless steel archwires (P < 0.05. Conclusion: Metal insert ceramic bracket with stainless steel archwire is the best possible combination among the materials studied because it generated the least frictional resistance during simulated tooth movement.

  15. Temperature dependence of ice-on-rock friction at realistic glacier conditions

    Science.gov (United States)

    McCarthy, C.; Savage, H.; Nettles, M.

    2017-02-01

    Using a new biaxial friction apparatus, we conducted experiments of ice-on-rock friction in order to better understand basal sliding of glaciers and ice streams. A series of velocity-stepping and slide-hold-slide tests were conducted to measure friction and healing at temperatures between -20°C and melting. Experimental conditions in this study are comparable to subglacial temperatures, sliding rates and effective pressures of Antarctic ice streams and other glaciers, with load-point velocities ranging from 0.5 to 100 µm s-1 and normal stress σn = 100 kPa. In this range of conditions, temperature dependences of both steady-state friction and frictional healing are considerable. The friction increases linearly with decreasing temperature (temperature weakening) from μ = 0.52 at -20°C to μ = 0.02 at melting. Frictional healing increases and velocity dependence shifts from velocity-strengthening to velocity-weakening behaviour with decreasing temperature. Our results indicate that the strength and stability of glaciers and ice streams may change considerably over the range of temperatures typically found at the ice-bed interface. This article is part of the themed issue 'Microdynamics of ice'.

  16. Development of a Low-Cost and High-speed Single Event Effects Testers based on Reconfigurable Field Programmable Gate Arrays (FPGA)

    Science.gov (United States)

    Howard, J. W.; Kim, H.; Berg, M.; LaBel, K. A.; Stansberry, S.; Friendlich, M.; Irwin, T.

    2006-01-01

    A viewgraph presentation on the development of a low cost, high speed tester reconfigurable Field Programmable Gata Array (FPGA) is shown. The topics include: 1) Introduction; 2) Objectives; 3) Tester Descriptions; 4) Tester Validations and Demonstrations; 5) Future Work; and 6) Summary.

  17. Fault Frictional Stability in a Nuclear Waste Repository

    Science.gov (United States)

    Orellana, Felipe; Violay, Marie; Scuderi, Marco; Collettini, Cristiano

    2016-04-01

    Exploitation of underground resources induces hydro-mechanical and chemical perturbations in the rock mass. In response to such disturbances, seismic events might occur, affecting the safety of the whole engineering system. The Mont Terri Rock Laboratory is an underground infrastructure devoted to the study of geological disposal of nuclear waste in Switzerland. At the site, it is intersected by large fault zones of about 0.8 - 3 m in thickness and the host rock formation is a shale rock named Opalinus Clay (OPA). The mineralogy of OPA includes a high content of phyllosilicates (50%), quartz (25%), calcite (15%), and smaller proportions of siderite and pyrite. OPA is a stiff, low permeable rock (2×10-18 m2), and its mechanical behaviour is strongly affected by the anisotropy induced by bedding planes. The evaluation of fault stability and associated fault slip behaviour (i.e. seismic vs. aseismic) is a major issue in order to ensure the long-term safety and operation of the repository. Consequently, experiments devoted to understand the frictional behaviour of OPA have been performed in the biaxial apparatus "BRAVA", recently developed at INGV. Simulated fault gouge obtained from intact OPA samples, were deformed at different normal stresses (from 4 to 30 MPa), under dry and fluid-saturated conditions. To estimate the frictional stability, the velocity-dependence of friction was evaluated during velocity steps tests (1-300 μm/s). Slide-hold-slide tests were performed (1-3000 s) to measure the amount of frictional healing. The collected data were subsequently modelled with the Ruina's slip dependent formulation of the rate and state friction constitutive equations. To understand the deformation mechanism, the microstructures of the sheared gouge were analysed. At 7 MPa normal stress and under dry conditions, the friction coefficient decreased from a peak value of μpeak,dry = 0.57 to μss,dry = 0.50. Under fluid-saturated conditions and same normal stress, the

  18. Student figures in friction

    DEFF Research Database (Denmark)

    Nielsen, Gritt B.

      This thesis analyses how ‘the student', as a contested figure, is negotiated and enacted in a period of extensive university reform in Denmark. Through a combination of historical and anthropological research, it focuses on students' changing participation in the shaping of Danish society......, students' room for participation in their own learning, influenced by demands for efficiency, flexibility and student-centred education. The thesis recasts the anthropological endeavour as one of ‘figuration work'. That is, ‘frictional events' are explored as moments when conflicting figures......, the university and their own education. Detailed studies explore, first, politically active students' various attempts to influence national educational policies; second, student participation in the development of the university, especially regarding debates over consumer conduct versus co-ownership; and third...

  19. Spine growth mechanisms: friction and seismicity at Mt. Unzen, Japan

    Science.gov (United States)

    Hornby, Adrian; Kendrick, Jackie; Hirose, Takehiro; Henton De Angelis, Sarah; De Angelis, Silvio; Umakoshi, Kodo; Miwa, Takahiro; Wadsworth, Fabian; Dingwell, Don; Lavallee, Yan

    2014-05-01

    The final episode of dome growth during the 1991-1995 eruption of Mt. Unzen was characterised by spine extrusion accompanied by repetitive seismicity. This type of cyclic activity has been observed at several dome-building volcanoes and recent work suggests a source mechanism of brittle failure of magma in the conduit. Spine growth may proceed by densification and closure of permeable pathways within the uppermost conduit magma, leading to sealing of the dome and inflation of the edifice. Amplified stresses on the wall rock and plug cause brittle failure near the conduit wall once static friction forces are overcome, and during spine growth these fractures may propagate to the dome surface. The preservation of these features is rare, and the conduit is typically inaccessible; therefore spines, the extruded manifestation of upper conduit material, provide the opportunity to study direct evidence of brittle processes in the conduit. At Mt. Unzen the spine retains evidence for brittle deformation and slip, however mechanical constraints on the formation of these features and their potential impact on eruption dynamics have not been well constrained. Here, we conduct an investigation into the process of episodic spine growth using high velocity friction apparatus at variable shear slip rate (0.4-1.5 m.s-1) and normal stress (0.4-3.5 MPa) on dome rock from Mt. Unzen, generating frictional melt at velocity >0.4 m.s-1 and normal stress >0.7 MPa. Our results show that the presence of frictional melt causes a deviation from Byerlee's frictional rule for rock friction. Melt generation is a disequilibrium process: initial amphibole breakdown leads to melt formation, followed by chemical homogenization of the melt layer. Ultimately, the experimentally generated frictional melts have a similar final chemistry, thickness and comminuted clast size distribution, thereby facilitating the extrapolation of a single viscoelastic model to describe melt-lubricated slip events at Mt

  20. Fluidized bed calciner apparatus

    Science.gov (United States)

    Owen, Thomas J.; Klem, Jr., Michael J.; Cash, Robert J.

    1988-01-01

    An apparatus for remotely calcining a slurry or solution feed stream of toxic or hazardous material, such as ammonium diurante slurry or uranyl nitrate solution, is disclosed. The calcining apparatus includes a vertical substantially cylindrical inner shell disposed in a vertical substantially cylindrical outer shell, in which inner shell is disposed a fluidized bed comprising the feed stream material to be calcined and spherical beads to aid in heat transfer. Extending through the outer and inner shells is a feed nozzle for delivering feed material or a cleaning chemical to the beads. Disposed in and extending across the lower portion of the inner shell and upstream of the fluidized bed is a support member for supporting the fluidized bed, the support member having uniform slots for directing uniform gas flow to the fluidized bed from a fluidizing gas orifice disposed upstream of the support member. Disposed in the lower portion of the inner shell are a plurality of internal electric resistance heaters for heating the fluidized bed. Disposed circumferentially about the outside length of the inner shell are a plurality of external heaters for heating the inner shell thereby heating the fluidized bed. Further, connected to the internal and external heaters is a means for maintaining the fluidized bed temperature to within plus or minus approximately 25.degree. C. of a predetermined bed temperature. Disposed about the external heaters is the outer shell for providing radiative heat reflection back to the inner shell.

  1. REDUCED ENGINE FRICTION AND WEAR

    Energy Technology Data Exchange (ETDEWEB)

    Ron Matthews

    2005-05-01

    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

  2. Frictional properties of confined polymers

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Samoilov, Vladimir N; Persson, Bo N J

    2008-01-01

    We present molecular dynamics friction calculations for confined hydrocarbon solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: a) polymer sliding against a hard substrate, and b) polymer sliding on polymer. In the first setup the shear stresses are relatively...... independent of molecular length. For polymer sliding on polymer the friction is significantly larger, and dependent on the molecular chain length. In both cases, the shear stresses are proportional to the squeezing pressure and finite at zero load, indicating an adhesional contribution to the friction force...

  3. Neutron detection apparatus and method

    Energy Technology Data Exchange (ETDEWEB)

    Derzon, Mark S.; Borek, III, Theodore T.

    2017-08-15

    An apparatus for neutron detection is provided. The apparatus comprises a sensor medium in electrical contact with an electrode arrangement conformed to collect radiation-generated charge from the sensor medium. The sensor medium comprises a borazine and/or a borazine-based polymer.

  4. Heat Treating Apparatus

    Science.gov (United States)

    De Saro, Robert; Bateman, Willis

    2002-09-10

    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.

  5. FLUID CONTACTOR APPARATUS

    Science.gov (United States)

    Spence, R.; Streeton, R.J.W.

    1956-04-17

    The fluid contactor apparatus comprises a cylindrical column mounted co- axially and adapted to rotate within a cylindrical vessel, for the purpose of extracting a solute from am aqueous solution by means of an organic solvent. The column is particularly designed to control the vortex pattern so as to reduce the height of the vortices while, at the same time, the width of the annular radius in the radial direction between the vessel and column is less than half the radius of the column. A plurality of thin annular fins are spaced apart along the rotor approximately twice the radial dimension of the column such that two contrarotating substantially circular vortices are contained within each pair of fins as the column is rotated.

  6. Spine immobilization apparatus

    Science.gov (United States)

    Lambson, K. H.; Vykukal, H. C. (Inventor)

    1981-01-01

    The apparatus makes use of a normally flat, flexible bladder filled with beads or micro-balloons that form a rigid mass when the pressure within the bladder is decreased below ambient through the use of a suction pump so that the bladder can be conformed to the torso of the victim and provide the desired restraint. The bladder is strapped to the victim prior to being rigidified by an arrangement of straps which avoid the stomach area. The bladder is adapted to be secured to a rigid support, i.e., a rescue chair, so as to enable removal of a victim after the bladder has been made rigid. A double sealing connector is used to connect the bladder to the suction pump and a control valve is employed to vary the pressure within the bladder so as to soften and harden the bladder as desired.

  7. A Pedagogical Model of Static Friction

    CERN Document Server

    Pickett, Galen T

    2015-01-01

    While dry Coulombic friction is an elementary topic in any standard introductory course in mechanics, the critical distinction between the kinetic and static friction forces is something that is both hard to teach and to learn. In this paper, I describe a geometric model of static friction that may help introductory students to both understand and apply the Coulomb static friction approximation.

  8. Archimedes force on Casimir apparatus

    Science.gov (United States)

    Shevchenko, V.; Shevrin, E.

    2016-11-01

    The talk addresses a problem of Casimir apparatus in weak gravitational field, surrounded by a dense medium. The falling of the apparatus has to be governed by the equivalence principle, taking into account proper contributions to the weight of the apparatus from its material part and from distorted quantum fields. We discuss general ex pression for the corresponding force in terms of the effective action. By way of example we compute explicit expression for Archimedes force, acting on the Casimir apparatus of finite size, immersed into thermal bath of free scalar field. It is shown that besides universal term, proportional to the volume of the apparatus, there are non-universal quantum corrections, depending on the boundary conditions.

  9. Archimedes force on Casimir apparatus

    Directory of Open Access Journals (Sweden)

    Shevchenko V.

    2016-01-01

    Full Text Available The talk addresses a problem of Casimir apparatus in weak gravitational field, surrounded by a dense medium. The falling of the apparatus has to be governed by the equivalence principle, taking into account proper contributions to the weight of the apparatus from its material part and from distorted quantum fields. We discuss general ex pression for the corresponding force in terms of the effective action. By way of example we compute explicit expression for Archimedes force, acting on the Casimir apparatus of finite size, immersed into thermal bath of free scalar field. It is shown that besides universal term, proportional to the volume of the apparatus, there are non-universal quantum corrections, depending on the boundary conditions.

  10. Specifications for gas treatment apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Teraoka, Yuden; Yoshigoe, Akitaka [Japan Atomic Energy Research Inst., Kansai Research Establishment, Synchrotron Radiation Research Center, Mikazuki, Hyogo (Japan)

    2001-03-01

    A surface reaction analysis apparatus was installed as an experimental end-station for the study of surface chemistry at the JAERI soft x-ray beamline in the SPring-8. The surface reaction analysis apparatus is devoted to the study of reaction mechanisms on solid surfaces with incident gas molecules. It is necessary to supply reagent gases to the apparatus. Chlorine and metal organic molecules will be used in the apparatus as well as oxygen molecules. Since the chlorine is corrosive and virulent, the metal organic molecules are flammable, the satiety treatments and the removal of virulence from the exhaust gas are needed. This gas supply and exhaust system is mainly composed of a cylinder cabinet, a gas mixer, a virulence removal cell and an urgent virulence removal apparatus. The former three devices are considered to take a countermeasure against virulent gas leak. The detail specifications concerning the gas supply and exhaust system are described in this report. (author)

  11. Microelectromechanical acceleration-sensing apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Robb M. (Albuquerque, NM); Shul, Randy J. (Albuquerque, NM); Polosky, Marc A. (Albuquerque, NM); Hoke, Darren A. (Albuquerque, NM); Vernon, George E. (Rio Rancho, NM)

    2006-12-12

    An acceleration-sensing apparatus is disclosed which includes a moveable shuttle (i.e. a suspended mass) and a latch for capturing and holding the shuttle when an acceleration event is sensed above a predetermined threshold level. The acceleration-sensing apparatus provides a switch closure upon sensing the acceleration event and remains latched in place thereafter. Examples of the acceleration-sensing apparatus are provided which are responsive to an acceleration component in a single direction (i.e. a single-sided device) or to two oppositely-directed acceleration components (i.e. a dual-sided device). A two-stage acceleration-sensing apparatus is also disclosed which can sense two acceleration events separated in time. The acceleration-sensing apparatus of the present invention has applications, for example, in an automotive airbag deployment system.

  12. Friction Material Composites Materials Perspective

    CERN Document Server

    Sundarkrishnaa, K L

    2012-01-01

    Friction Material Composites is the first of the five volumes which strongly educates and updates engineers and other professionals in braking industries, research and test labs. It explains besides the formulation of design processes and its complete manufacturing input. This book gives an idea of mechanisms of friction and how to control them by designing .The book is  useful for designers  of automotive, rail and aero industries for designing the brake systems effectively with the integration of friction material composite design which is critical. It clearly  emphasizes the driving  safety and how serious designers should  select the design input. The significance of friction material component like brake pad or a liner as an integral part of the brake system of vehicles is explained. AFM pictures at nanolevel illustrate broadly the explanations given.

  13. Proficiency testing of skin prick testers as part of a quality assurance system

    DEFF Research Database (Denmark)

    Malling, Hans-Jørgen; Allesen-Holm, Pernille; Karved, Lisbeth Sys

    2016-01-01

    of variation (CV 0.85) based on blinded octuplicate histamine testing using histamine 3, 10, 30 and 100 mg/ml. RESULTS: Fourteen trained allergy nurses participated in the proficiency testing. More than 95 % of the nurses, generated coefficient of variation...... less than 40 %, and for around 35 % of testers the CV were below 20 % based on wheal area. Regarding the linearity (coefficient of regression), only two nurses produced tests with a value below 0.85. On the contrary, 79 % of testers demonstrated a coefficient of regression >0.95. Depending...... on the gentleness of the prick procedure, the inter-nurse variability in wheal area varied more than twofold corresponding to a 10-doubling of histamine concentration. This would never have been detected without using a proficiency testing system. CONCLUSION: The described histamine testing provides an objective...

  14. Assessment of laboratory-aged insulating materials using the mini-static tester

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, P.J.; Finnan, E. [Doble Engineering Co., Watertown, MA (United States)

    1995-05-01

    A better understanding of the electrostatic charging tendency of aged materials is required as there have been failures of {open_quotes}middle-aged{close_quotes} transformers from the effects of static electrification. The mini-static tester was used as a means to evaluate the effects on the electrostatic charging tendency (ECT) of aging both oil and paper under accelerated conditions. Two mineral oils presently manufactured in the US were aged with various mixtures of Kraft, thermally-upgraded Kraft, paper filters used in the mini-static tester, and benzotriazole (BTA), a static suppressant. A copper catalyst and elevated temperature (120{degrees}C) were the primary factors in accelerating the aging of materials in a low oxygen environment. Results showed that aging of both insulating materials affected their electrostatic charging tendency. There were some indications that BTA altered the ECT of the insulating materials after a period of time.

  15. Different testers influence genetic correlational response in narrow-based maize population NSA15

    Directory of Open Access Journals (Sweden)

    Stanisavljević Dušan

    2015-01-01

    Full Text Available The goal of this study was to determine correlations between grain yield and other morphological and agronomical traits in two groups of maize half-sib (HS progenies. Progenies were obtained by crossing every S1 family with two unrelated inbred lines as testers, NS732 and NS27. Field trials with incomplete block design, with replicates within set were conducted in 2008 and 2009 at four locations. The following traits were observed: grain yield, ear length, kernel row number, kernel number per row, 1000-kernel weight, plant height, ear height, number of leaves above ear and grain moisture. Significant moderate strong negative correlation between grain yield and ear length was determined in HS1 progeny. High significant correlations occurred among plant and ear height in both HS and between plant height and number of leaves. Observed differences in levels of correlation imply significant influence of tester in each group on HS progeny.

  16. Head position control on quasi-static read/write tester

    Science.gov (United States)

    Kusumi, Takayuki; Yamakawa, Kiyoshi; Ouchi, Kazuhiro

    2005-02-01

    To develop high-density magnetic recording systems, a simple feedback system without servo writing was applied to a quasi-static read/write tester in which a medium reciprocates against a stand-still head. The head position signal in cross-track direction during the scanning is fed back to the high-precision piezoelectric actuator of the media stage. The stage is controlled so as to make the head/medium alignment error zero. A contact head slider assembled on a parallel-link suspension was used to evaluate the feedback system. The tester shows an accuracy of 1.5 nm in cross-track direction which is preferable for the read/write tests at future high recording densities.

  17. Kinetic Friction Coefficient of Ice,

    Science.gov (United States)

    1985-03-01

    For the hardest ice tested (xi = 0.33 described by Rabinowicz (1965), where To is inter- mm, H, = 1525 kPa), the calculated values of a preted as...material with a low elastic pressures. The frictional force was measured at modulus ( Rabinowicz 1965). It has been observed the application point of...tion 10, pp. 8-16. Barnes, P. and D. Tabor (1966) Plastic flow and Rabinowicz , E. (1965) Friction and Wear of Mate- pressure melting in the deformation

  18. Peak mass and dynamical friction

    CERN Document Server

    Del Popolo, A

    1995-01-01

    We show how the results given by several authors relatively to the mass of a density peak are changed when small scale substructure induced by dynamical friction are taken into account. The peak mass obtained is compared to the result of Peacock \\& Heavens (1990) and to the peak mass when dynamical friction is absent to show how these effects conspire to reduce the mass accreted by the peak.

  19. Tire/runway friction interface

    Science.gov (United States)

    Yager, Thomas J.

    1990-01-01

    An overview is given of NASA Langley's tire/runway pavement interface studies. The National Tire Modeling Program, evaluation of new tire and landing gear designs, tire wear and friction tests, and tire hydroplaning studies are examined. The Aircraft Landing Dynamics Facility is described along with some ground friction measuring vehicles. The major goals and scope of several joint FAA/NASA programs are identified together with current status and plans.

  20. Labor Supply and Optimization Frictions

    DEFF Research Database (Denmark)

    Søgaard, Jakob Egholt

    2015-01-01

    In this paper I investigate the nature of optimization frictions by studying the labor market of Danish students. This particular labor market is an interesting case study as it features a range of special institutional settings that affect students’ incentive to earn income and comparing outcomes...... theory. More concretely I find the dominate optimization friction to be individuals’ inattention about their earnings during the year, while real adjustment cost and gradual learning appears to be of less importance....

  1. Evaluation of bearing configurations using the single bearing tester in liquid nitrogen

    Science.gov (United States)

    Jett, T.; Hall, P.; Thom, R.

    1991-01-01

    Various bearing configurations were tested using the Marshall Space Flight Center single bearing tester with LN2 as the cryogenic coolant. The baseline was one Rocketdyne phase one high pressure oxidizer turbopump (HPOTP) pump end 45-mm bore bearing. The bearing configurations that were tested included a Salox/M cage configuration, a silicon nitride ball configuration, an elongated cage configuration, and a Bray 601 grease configuration.

  2. Intelligent Tester for Geotextiles Products-Determination of Water Flow Capacity in their Plane

    Institute of Scientific and Technical Information of China (English)

    FENG Yu-sheng; SONG Bai-ping

    2004-01-01

    Geotextiles and geotextile-related products Determination of water flowcapacity in their plane has just National standard. But has not a formal instrument at present. There are many kinds of geotextile and also lots of factors influential to the penetration coefficient thereof. The intelligent tester may be involved in testing penetration coefficient under different pressures/gradients resulted in fine repeatability controlled intelligently by microcomputer system.

  3. The Influence of Indenter Rotation Angle on The Quality of Vicker Tester Calibration

    OpenAIRE

    Jozef Petrík

    2011-01-01

    The object of submitted work is to analyze the influence of the rotation of the indenter (diamond pyramid) and test force on the result of Vickers hardness tester calibration using uncertainty analysis, Measurement systems analysis (MSA), analysis of variance (ANOVA) and Z-score.  The rotation anmgle of  indenter affects the values of hardness, repeatability rrel, maximal error Erel and relative expanded uncertainty Urel. The significance of the angle of indenter on the hardness and observed ...

  4. Frictional Effects on Gear Tooth Contact Analysis

    OpenAIRE

    Zheng Li; Ken Mao

    2013-01-01

    The present paper concentrates on the investigations regarding the situations of frictional shear stress of gear teeth and the relevant frictional effects on bending stresses and transmission error in gear meshing. Sliding friction is one of the major reasons causing gear failure and vibration; the adequate consideration of frictional effects is essential for understanding gear contact behavior accurately. An analysis of tooth frictional effect on gear performance in spur gear is presented us...

  5. The design and analysis of single flank transmission error tester for loaded gears

    Science.gov (United States)

    Bassett, Duane E.; Houser, Donald R.

    1987-01-01

    To strengthen the understanding of gear transmission error and to verify mathematical models which predict them, a test stand that will measure the transmission error of gear pairs under design loads has been investigated. While most transmission error testers have been used to test gear pairs under unloaded conditions, the goal of this report was to design and perform dynamic analysis of a unique tester with the capability of measuring the transmission error of gears under load. This test stand will have the capability to continuously load a gear pair at torques up to 16,000 in-lb at shaft speeds from 0 to 5 rpm. Error measurement will be accomplished with high resolution optical encoders and the accompanying signal processing unit from an existing unloaded transmission error tester. Input power to the test gear box will be supplied by a dc torque motor while the load will be applied with a similar torque motor. A dual input, dual output control system will regulate the speed and torque of the system. This control system's accuracy and dynamic response were analyzed and it was determined that proportional plus derivative speed control is needed in order to provide the precisely constant torque necessary for error-free measurement.

  6. Erosion-corrosion investigation of high chromium cast irons using newly designed jet type tester

    Institute of Scientific and Technical Information of China (English)

    TU Xiao-hui; LIU Jun-quan; LI Wei; ZHANG Feng-hua; SU Jun-yi

    2004-01-01

    A jet type erosion-corrosion tester was developed for the erosion-corrosion investigation of high-chromium cast irons. During tests the size and the shape of particles in the slurry can be maintained stable. The jet velocity and attack angle can be accurately controlled. The repeatability and ranking consistency of the test results are satisfactory. The test parameters can be adjusted in a wide range, so that the tester can simulate various practical working conditions. Electrochemical test data can be automatically collected and processed. Dynamic polarization curves can be obtained during erosion-corrosion test, which can be used to study the dynamic corrosion characteristics.Two high chromium cast irons were studied in hot concentrated alkaline slurry. The results show that the erosioncorrosion mass loss rate and dynamic corrosion rate of 295Cr26 iron is lower than that of 185Cr13 under the conditions similar to alumyte processing. The mechanism of erosion-corrosion of 295Cr26 and 185Cr13 was studied by using the tester. The interaction between erosion and corrosion was also quantitatively evaluated.

  7. Effect of pulp tester probe placement site on the response of maxillary anterior teeth

    Directory of Open Access Journals (Sweden)

    Jalil Modaresi

    2012-01-01

    Full Text Available Background and Aims: Electric pulp testing is used for diagnosis of the pulp status. This test is technique sensitive and hence may elicit positive or negative false response in case of inaccurate use. The optimal site for placement of the probe tip has not been determined. The aim of this study was to evaluate the effect of pulp tester probe placement site on the response of maxillary teeth.Materials and Methods: A total of 378 teeth (126 central incisors, 126 lateral incisors and 126 canines in 67 voluntary 20-35 year-old patients were selected. Three sites on each tooth (incisal edge, labial and lingual surfaces were tested with an electrical pulp tester and responses were recorded. Data were analyzed by Repeated Measure ANOVA test.Results: The central teeth showed significantly lower sensation threshold than lateral and canine teeth (P<0.001. The incisal edge of tooth were significantly more sensitive compared to labial and lingual surfaces (P=0.008.Conclusion: This study showed that the optimum site for placement of pulp tester probe was incisal edge.

  8. Tester og testtilbakemeldinger som direkte bidragsytere til dypere læring blant studenter

    Directory of Open Access Journals (Sweden)

    Henrik Herrebrøden

    2014-11-01

    Full Text Available Denne artikkelen diskuterer forskning som tilsier at tester og testtilbakemeldinger kan bidra til dypere læring blant studenter. Testing har vist seg å forbedre langtidshukommelsen av innlært kunnskap sammenlignet med repetert lesing, noe som kalles for testeffekten. For at testeffekten skal optimaliseres, bør tester utformes med mål om å bidra til dyp prosessering av innlært kunnskap. Testtilbakemeldingers rolle i utdanning kan være å bidra til økt metakognitiv selvregulering blant studenter. For at selvregulering skal promoteres best mulig, bør testtilbakemeldinger inneholde utdypende informasjon. Samlet ser tester og testtilbakemeldinger ut til å være nyttige læringsverktøy og potensielle bidragsytere til dypere læring blant studenter.AbstractThis article discusses research supporting that tests and test feedback are learning tools that may promote deeper learning among students. Testing improves long-term retention of knowledge compared to repeated study, a phenomenon known as the testing effect. In order to promote the testing effect, tests should facilitate deep processing of knowledge among students. Test feedback has the potential to increase students’ metacognitive self-regulation. For this type of metacognition to be enhanced, feedback should contain elaborate information. Conclusively, tests and test feedback appear to be valuable learning tools and potential promoters of deeper learning.

  9. A dynamic tester to evaluate the thermal and moisture behaviour of the surface of textiles.

    Science.gov (United States)

    Li, Wenbin; Xu, Weilin; Wang, Hao; Wang, Xin

    2016-01-01

    The thermal and moisture behaviour of the microclimate of textiles is crucial in determining the physiological comfort of apparel, but it has not been investigated sufficiently due to the lack of particular evaluation techniques. Based on sensing, temperature controlling and wireless communicating technology, a specially designed tester has been developed in this study to evaluate the thermal and moisture behaviour of the surface of textiles in moving status. A temperature acquisition system and a temperature controllable hotplate have been established to test temperature and simulate the heat of human body, respectively. Relative humidity of the surface of fabric in the dynamic process has been successfully tested through sensing. Meanwhile, wireless communication technology was applied to transport the acquired data of temperature and humidity to computer for further processing. Continuous power supply was achieved by intensive contact between an elastic copper plate and copper ring on the rotating shaft. This tester provides the platform to evaluate the thermal and moisture behaviour of textiles. It enables users to conduct a dynamic analysis on the temperature and humidity together with the thermal and moisture transport behaviour of the surface of fabric in moving condition. Development of this tester opens the door of investigation on the micro-climate of textiles in real time service, and eventually benefits the understanding of the sensation comfort and wellbeing of apparel wearers.

  10. Design of a Pneumatic Robotic Arm for Solar Cell Tester System By using PLC controller

    Directory of Open Access Journals (Sweden)

    Yousif I. Al Mashhadany

    2013-01-01

    Full Text Available Solar cell testers sort photovoltaic cells according to their electrical performance, tested under simulated sunlight. A variety of testers exist, but they all face a common challenge of handling cells that are very small and thin, which makes it difficult to transport the cells from the conveyer to the storage box. This paper presents a new design for a handling robot with vacuum end-effectors, which uses a PLC controller to govern the movement of the cells and the testing process. The design applies to solar cell testers for monocrystalline, polycrystalline, cadmium telluride (CdTe, and copper indium diselenide (CIS cells. Each cell is tested for efficiency and categorized accordingly into four groups (A to D. A Virtual Reality (VR model was built to simulate the system, keeping in mind real world constraints. Two photoelectric sensors were used to make detections for both the testing process and the robot movement. The PLC controller guides the trajectory of the robot according to the results of the efficiency testing. It was seen that the system worked very well, with the testing process and the robot movement interacting smoothly. The robot trajectory was seen to be highly accurate, and the pick and place operations were done with great precision.

  11. Friction and Wear Properties of Cold Gas Dynamic Sprayed α-Al2O3-Al Composite Coatings

    Directory of Open Access Journals (Sweden)

    Jie Wu

    2013-01-01

    Full Text Available Different proportions of α-Al2O3 and pure Al powders were coated onto AZ91D magnesium alloy substrates by cold gas dynamic spray. The microstructure and morphologies of the coatings were observed by scanning electron microscope. The friction and wear properties were tested by a ball-on-disk wear tester. It was found that the interfaces between grains and substrates formed close boundaries. It is revealed that the composite coatings could increase the friction or wear properties of the coatings. It was observed that the wear of coatings was converted from adhesive wear into abrasive wear with α-Al2O3 particles increasing and that the adhesive wear accompanied with abrasive wear would increase the wear rate of coatings.

  12. Research on friction coefficient of nuclear Reactor Vessel Internals Hold Down Spring: Stress coefficient test analysis method

    Energy Technology Data Exchange (ETDEWEB)

    Linjun, Xie, E-mail: linjunx@zjut.edu.cn [College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Guohong, Xue; Ming, Zhang [Shanghai Nuclear Engineering Research & Design Institute, Shanghai 200233 (China)

    2016-08-01

    Graphical abstract: HDS stress coefficient test apparatus. - Highlights: • This paper performs mathematic deduction to the physical model of Hold Down Spring (HDS), establishes a mathematic model of axial load P and stress, stress coefficient and friction coefficient and designs a set of test apparatuses for simulating the pretightening process of the HDS for the first time according to a model similarity criterion. • The mathematical relation between the load and the strain is obtained about the HDS, and the mathematical model of the stress coefficient and the friction coefficient is established. So, a set of test apparatuses for obtaining the stress coefficient is designed according to the model scaling criterion and the friction coefficient of the K1000 HDS is calculated to be 0.336 through the obtained stress coefficient. • The relation curve between the theoretical load and the friction coefficient is obtained through analysis and indicates that the change of the friction coefficient f would influence the pretightening load under the condition of designed stress. The necessary pretightening load in the design process is calculated to be 5469 kN according to the obtained friction coefficient. Therefore, the friction coefficient and the pretightening load under the design conditions can provide accurate pretightening data for the analysis and design of the reactor HDS according to the operations. - Abstract: This paper performs mathematic deduction to the physical model of Hold Down Spring (HDS), establishes a mathematic model of axial load P and stress, stress coefficient and friction coefficient and designs a set of test apparatuses for simulating the pretightening process of the HDS for the first time according to a model similarity criterion. By carrying out tests and researches through a stress testing technique, P–σ curves in loading and unloading processes of the HDS are obtained and the stress coefficient k{sub f} of the HDS is obtained. So, the

  13. Hip strength assessment using handheld dynamometry is subject to intertester bias when testers are of different sex and strength

    DEFF Research Database (Denmark)

    Thorborg, K; Bandholm, T; Schick, M

    2013-01-01

    of this study was to examine the intertester reliability concerning strength assessments of hip abduction, adduction, external and internal rotation, flexion and extension using HHD, and to test whether systematic differences in test values exist between testers of different upper-extremity strength. Fifty...... reliability, and ranged from 0.82 to 0.91 for the six strength test. The female tester systematically measured lower strength values for all isometric strength tests (P ...

  14. Automated Desalting Apparatus

    Science.gov (United States)

    Spencer, Maegan K.; Liu, De-Ling; Kanik, Isik; Beegle, Luther

    2010-01-01

    Because salt and metals can mask the signature of a variety of organic molecules (like amino acids) in any given sample, an automated system to purify complex field samples has been created for the analytical techniques of electrospray ionization/ mass spectroscopy (ESI/MS), capillary electrophoresis (CE), and biological assays where unique identification requires at least some processing of complex samples. This development allows for automated sample preparation in the laboratory and analysis of complex samples in the field with multiple types of analytical instruments. Rather than using tedious, exacting protocols for desalting samples by hand, this innovation, called the Automated Sample Processing System (ASPS), takes analytes that have been extracted through high-temperature solvent extraction and introduces them into the desalting column. After 20 minutes, the eluent is produced. This clear liquid can then be directly analyzed by the techniques listed above. The current apparatus including the computer and power supplies is sturdy, has an approximate mass of 10 kg, and a volume of about 20 20 20 cm, and is undergoing further miniaturization. This system currently targets amino acids. For these molecules, a slurry of 1 g cation exchange resin in deionized water is packed into a column of the apparatus. Initial generation of the resin is done by flowing sequentially 2.3 bed volumes of 2N NaOH and 2N HCl (1 mL each) to rinse the resin, followed by .5 mL of deionized water. This makes the pH of the resin near neutral, and eliminates cross sample contamination. Afterward, 2.3 mL of extracted sample is then loaded into the column onto the top of the resin bed. Because the column is packed tightly, the sample can be applied without disturbing the resin bed. This is a vital step needed to ensure that the analytes adhere to the resin. After the sample is drained, oxalic acid (1 mL, pH 1.6-1.8, adjusted with NH4OH) is pumped into the column. Oxalic acid works as a

  15. Apparatus for measuring particle properties

    Science.gov (United States)

    Rader, D.J.; Castaneda, J.N.; Grasser, T.W.; Brockmann, J.E.

    1998-08-11

    An apparatus is described for determining particle properties from detected light scattered by the particles. The apparatus uses a light beam with novel intensity characteristics to discriminate between particles that pass through the beam and those that pass through an edge of the beam. The apparatus can also discriminate between light scattered by one particle and light scattered by multiple particles. The particle`s size can be determined from the intensity of the light scattered. The particle`s velocity can be determined from the elapsed time between various intensities of the light scattered. 11 figs.

  16. The influence of surface topography on the forming friction of automotive aluminum sheet

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, Pamela Ann [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

    1998-05-01

    Interest in utilizing aluminum alloys in automobiles has increased in recent years as a result of the desire to lower automobile weight and, consequently, increase fuel economy. While aluminum alloy use in cast parts has increased, outer body panel applications are still being investigated. The industry is interested in improving the formability of these sheet alloys by a combination of alloy design and processing. A different avenue of improving the formability of these alloys may be through patterning of the sheet surface. Surface patterns hold the lubricant during the forming process, with a resulting decrease in the sheet-die surface contact. While it has been speculated that an optimum surface pattern would consist of discrete cavities, detailed investigation into the reduction of forming friction by utilizing discrete patterns is lacking. A series of discrete patterns were investigated to determine the dependence of the forming friction of automotive aluminum alloys on pattern lubricant carrying capacity and on material strength. Automotive aluminum alloys used in outer body panel applications were rolled on experimental rolls that had been prepared with a variety of discrete patterns. All patterns for each alloy were characterized before and after testing both optically and, to determine pattern lubricant capacity, using three dimensional laser profilometry. A draw bead simulation (DBS) friction tester was designed and fabricated to determine the forming friction of the patterned sheets. Tensile testing and frictionless DBS testing were performed to ascertain the material properties of each sheet. The most striking result of this work was the inversely linear dependence of forming friction on the lubricant carrying capacity of the discrete patterns.

  17. Friction anisotropy in boronated graphite

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, N., E-mail: niranjan@igcar.gov.in [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Radhika, R. [Crystal Growth Centre, Anna University, Chennai (India); Kozakov, A.T. [Research Institute of Physics, Southern Federal University, Rostov-on-Don (Russian Federation); Pandian, R. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India); Chakravarty, S. [UGC-DAE CSR, Kalpakkam (India); Ravindran, T.R.; Dash, S.; Tyagi, A.K. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    2015-01-01

    Graphical abstract: - Highlights: • Friction anisotropy in boronated graphite is observed in macroscopic sliding condition. • Low friction coefficient is observed in basal plane and becomes high in prismatic direction. • 3D phase of boronated graphite transformed into 2D structure after friction test. • Chemical activity is high in prismatic plane forming strong bonds between the sliding interfaces. - Abstract: Anisotropic friction behavior in macroscopic scale was observed in boronated graphite. Depending upon sliding speed and normal loads, this value was found to be in the range 0.1–0.35 in the direction of basal plane and becomes high 0.2–0.8 in prismatic face. Grazing-incidence X-ray diffraction analysis shows prominent reflection of (0 0 2) plane at basal and prismatic directions of boronated graphite. However, in both the wear tracks (1 1 0) plane become prominent and this transformation is induced by frictional energy. The structural transformation in wear tracks is supported by micro-Raman analysis which revealed that 3D phase of boronated graphite converted into a disordered 2D lattice structure. Thus, the structural aspect of disorder is similar in both the wear tracks and graphite transfer layers. Therefore, the crystallographic aspect is not adequate to explain anisotropic friction behavior. Results of X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy shows weak signature of oxygen complexes and functional groups in wear track of basal plane while these species dominate in prismatic direction. Abundance of these functional groups in prismatic plane indicates availability of chemically active sites tends to forming strong bonds between the sliding interfaces which eventually increases friction coefficient.

  18. Versatile Friction Stir Welding/Friction Plug Welding System

    Science.gov (United States)

    Carter, Robert

    2006-01-01

    A proposed system of tooling, machinery, and control equipment would be capable of performing any of several friction stir welding (FSW) and friction plug welding (FPW) operations. These operations would include the following: Basic FSW; FSW with automated manipulation of the length of the pin tool in real time [the so-called auto-adjustable pin-tool (APT) capability]; Self-reacting FSW (SRFSW); SR-FSW with APT capability and/or real-time adjustment of the distance between the front and back shoulders; and Friction plug welding (FPW) [more specifically, friction push plug welding] or friction pull plug welding (FPPW) to close out the keyhole of, or to repair, an FSW or SR-FSW weld. Prior FSW and FPW systems have been capable of performing one or two of these operations, but none has thus far been capable of performing all of them. The proposed system would include a common tool that would have APT capability for both basic FSW and SR-FSW. Such a tool was described in Tool for Two Types of Friction Stir Welding (MFS- 31647-1), NASA Tech Briefs, Vol. 30, No. 10 (October 2006), page 70. Going beyond what was reported in the cited previous article, the common tool could be used in conjunction with a plug welding head to perform FPW or FPPW. Alternatively, the plug welding head could be integrated, along with the common tool, into a FSW head that would be capable of all of the aforementioned FSW and FPW operations. Any FSW or FPW operation could be performed under any combination of position and/or force control.

  19. Dry sliding friction and wear characteristics of Fe-C-Cu alloy containing molybdenum di sulphide

    Energy Technology Data Exchange (ETDEWEB)

    Dhanasekaran, S. [Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India); Gnanamoorthy, R. [Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India)]. E-mail: gmoorthy@iitm.ac.in

    2007-07-01

    Sintered steels find increasing application as bearings and gears due to economical and technical reasons. Materials used for making these machine elements need to have high strength, good wear resistance and low coefficient of friction. An attempt is made to develop molybdenum di sulphide added iron-copper-carbon sintered steels using simple single stage compaction and sintering elemental powders. Friction and wear characteristics of the developed materials were evaluated using cylindrical specimens in a pin-on-disc sliding apparatus. Addition of molybdenum di sulphide increases the compressibility and increases the part density. Strength and hardness of the molybdenum di sulphide added compositions are better than the base composition. Addition of the 3% molybdenum di sulphide is found to be beneficial in improving friction and wear characteristics. Higher amount of brittle phases in the 5% molybdenum di sulphide added sample contributes to the reduction in the wear resistance.

  20. Apparatus for photon excited catalysis

    Science.gov (United States)

    Saffren, M. M. (Inventor)

    1977-01-01

    An apparatus is described for increasing the yield of photonically excited gas phase reactions by extracting excess energy from unstable, excited species by contacting the species with the surface of a finely divided solid.

  1. Radioactive waste material melter apparatus

    Science.gov (United States)

    Newman, D.F.; Ross, W.A.

    1990-04-24

    An apparatus for preparing metallic radioactive waste material for storage is disclosed. The radioactive waste material is placed in a radiation shielded enclosure. The waste material is then melted with a plasma torch and cast into a plurality of successive horizontal layers in a mold to form a radioactive ingot in the shape of a spent nuclear fuel rod storage canister. The apparatus comprises a radiation shielded enclosure having an opening adapted for receiving a conventional transfer cask within which radioactive waste material is transferred to the apparatus. A plasma torch is mounted within the enclosure. A mold is also received within the enclosure for receiving the melted waste material and cooling it to form an ingot. The enclosure is preferably constructed in at least two parts to enable easy transport of the apparatus from one nuclear site to another. 8 figs.

  2. Cherry-Slush-Candling Apparatus

    Science.gov (United States)

    Stephens, James B.; Weiss, James R.; Hoover, Gordon

    1996-01-01

    Proposed infrared-scanning apparatus for use in bakeries making cherry pies detect cherry pits remaining in cherry slush after pitting process. Pits detected via their relative opacity to infrared radiation.

  3. Continuous steel production and apparatus

    Science.gov (United States)

    Peaslee, Kent D.; Peter, Jorg J.; Robertson, David G. C.; Thomas, Brian G.; Zhang, Lifeng

    2009-11-17

    A process for continuous refining of steel via multiple distinct reaction vessels for melting, oxidation, reduction, and refining for delivery of steel continuously to, for example, a tundish of a continuous caster system, and associated apparatus.

  4. Effect of Friction on the Drawing Process of Hot-Galvanized Sheet Steel

    Institute of Scientific and Technical Information of China (English)

    Hongying GONG; Wei ZHU; Zhiliang ZHANG; Zhenliang LOU

    2005-01-01

    A probe test method was employed to detect the friction condition of the interfaces between tools and blank. At the same time a self-developed measurement apparatus to realize the probe test method was also presented. Based on the analysis of force, a correlative friction model was also given. With the self-developed measurement apparatus,the effects of three kinds of lubricating oils which were in common use during the process of sheet steel drawing were studied. By probing the friction coefficient values of different lubricating oils during the drawing process of the hot-galvanized sheet steel (steel brand: ST07Zn), we can see that the friction caused by PK oil was the lowest, so the effect of PK oil was the best. Then PK oil was used as the base lubricating oil and some solid additive powers was added into it to make a new type lubrication (named as L oil).The result of test proved that the new lubricating oil had remarkable effect on the drawing process of hot-galvanized sheet steel.

  5. An Original Testing Apparatus for Rapid Pull-Out Test

    Directory of Open Access Journals (Sweden)

    Aprialdi, D.

    2014-01-01

    Full Text Available Pull-out test is commonly used to investigate the pull-out behavior of geotextile reinforcement embedded in soil. It is also used by different authors to propose interface friction angles values. Unfortunately these works mainly deal with cyclic loadings with reference to seismic action, which are believed to be different to the load exposed to reinforced earthworks due to lateral impacts. Therefore an original rapid pull-out test apparatus is proposed in this study. This article assess the proposed test method in addressing the rapid pull-out response of a geotextile embedded in soil. The testing apparatus allows investigating shear velocities within the range of 0.1 to 1.2 m/s. This test method seems promising in addressing the response of soil-geotextile interfaces under dynamic loadings. Nevertheless, improvements concerning the testing apparatus are still required. The loading system could be modified to avoid oscillations and specific equipment should be added to increase the normal stress.

  6. Apparatus Development In Maros

    Directory of Open Access Journals (Sweden)

    H. Aras Solong

    2015-03-01

    Full Text Available ABSTRACT This study aims to identify and describe 1 Development of Administrative through education and training training promotion transfer and rotation and the application of demotion system non-title under Law No. 43 of 1999 on the development of career civil servants based merit system and work performance and Government Regulation No. 101 of 2000 on Education and Training Training for Civil Servants. 2 Revealing differences in work motivation based on the intensity of the education or training training using Herzbergs Two Factor Theory of extrinsic factors hygiene and intrinsic factors motivator that influence employees motivation Maros regency government in carrying out its duties and functions as members civil in public service. This study uses a quantitative approach to date collection techniques through a questionnaire Questionnaire. Informant are civil servants who occupied echelon II III. And IV while the analysis of the date used quantitative analysis to uncover the implementation of personnel development and employees motivation difference Maros region based on the intensity of the education or training training to get job satisfaction in the public service. The results of this study will reveal that 1 Development of Apparatus for improving the knowledge ability professionalism competence skills can work as a reformer change attitude eager to work motivated to do the work get satisfaction in work and getting justice in employment. 2 The difference in work motivation Maros local government employees affected by extrinsic factors hygiene and intrinsic factor motivator is the variable gain high salary H occupies the first ranking while serving the community satisfaction variables M occupy the last ranking. That is that the satisfaction of serving the people affected by the high salaries earned by the employees to do the job.

  7. The Reality of Casimir Friction

    Directory of Open Access Journals (Sweden)

    Kimball A. Milton

    2016-04-01

    Full Text Available For more than 35 years theorists have studied quantum or Casimir friction, which occurs when two smooth bodies move transversely to each other, experiencing a frictional dissipative force due to quantum electromagnetic fluctuations, which break time-reversal symmetry. These forces are typically very small, unless the bodies are nearly touching, and consequently such effects have never been observed, although lateral Casimir forces have been seen for corrugated surfaces. Partly because of the lack of contact with observations, theoretical predictions for the frictional force between parallel plates, or between a polarizable atom and a metallic plate, have varied widely. Here, we review the history of these calculations, show that theoretical consensus is emerging, and offer some hope that it might be possible to experimentally confirm this phenomenon of dissipative quantum electrodynamics.

  8. The Reality of Casimir Friction

    CERN Document Server

    Milton, K A; Brevik, I

    2015-01-01

    For more than 35 years theorists have studied quantum or Casimir friction, which occurs when two smooth bodies move transversely to each other, experiencing a frictional dissipative force due to quantum fluctuations. These forces are typically very small, unless the bodies are nearly touching, and consequently such effects have never been observed, although lateral Casimir forces have been seen for corrugated surfaces. Because of the lack of contact with phenomena, theoretical predictions for the frictional force between parallel plates, or between a polarizable atom and a metallic plate, have varied widely. Here we review the history of these calculations, show that theoretical consensus is emerging, and offer some hope that it might be possible to experimentally confirm this phenomenon of dissipative quantum electrodynamics.

  9. The microphysics of phyllosilicate friction

    Science.gov (United States)

    den Hartog, Sabine A. M.; Faulkner, Daniel R.; Spiers, Christopher J.

    2017-04-01

    Phyllosilicate-rich foliations in fault rocks are often thought to reduce overall fault strength and promote fault stability when forming an interconnected network. Indeed, laboratory measurements have shown that the average friction coefficient of dry phyllosilicates of 0.5 is reduced to 0.3 when wet or even 0.1 for smectite. A widely accepted interpretation of these observations is that the strength of phyllosilicates is controlled by breaking of interlayer bonds to form new cleavage surfaces when dry and by the low strength of surface-bound water films when wet. However, the correlation between phyllosilicate shear strength and interlayer bond strength, which formed the basis for this interpretation, was not reproduced in recent experiments (Behnsen and Faulkner, 2012) and is not supported by the latest calculations of the interlayer bond energies (Sakuma and Suehara, 2015). The accepted explanation for phyllosilicate friction also fails to account for the velocity dependence or (a-b) values, which decrease with temperature, reaching a minimum at intermediate temperatures, before increasing again at higher temperatures (Den Hartog et al., 2013, 2014). In this study, we developed a microphysical model for phyllosilicate friction, involving frictional sliding along atomically flat phyllosilicate grain interfaces, with overlapping grain edges forming barriers to sliding. Assuming that the amount of overlap is controlled by crystal plastic bending of grains into pores, together with rate-dependent edge-site cleavage, our model predicts most of the experimentally observed trends in frictional behaviour and provides a basis for extrapolation of laboratory friction data on phyllosilicates to natural conditions.

  10. Low temperature friction force microscopy

    Science.gov (United States)

    Dunckle, Christopher Gregory

    The application of friction force techniques within atomic force microscopy (AFM) allows for direct measurements of friction forces at a sliding, single-asperity interface. The temperature dependence of such single-asperity contacts provides key insight into the comparative importance of dissipative mechanisms that result in dry sliding friction. A variable temperature (VT), ultrahigh vacuum (UHV) AFM was used with an interface consisting of a diamond coated AFM tip and diamond-like carbon sample in a nominal sample temperature range of 90 to 275K. The results show that the coefficient of kinetic friction, mu k, has a linear dependence that is monotonically increasing with temperature varying from 0.28 to 0.38. To analyze this data it is necessary to correlate the sample temperature to the interface temperature. A detailed thermal model shows that the sample temperature measured by a macroscopic device can be very different from the temperature at the contact point. Temperature gradients intrinsic to the design of VT, UHV AFMs result in extreme, non-equilibrium conditions with heat fluxes on the order of gigawatts per squared meter through the interface, which produce a discontinuous step in the temperature profile due to thermal boundary impedance. The conclusion from this model is that measurements acquired by VT, UHV AFM, including those presented in this thesis, do not provide meaningful data on the temperature dependence of friction for single-asperities. Plans for future work developing an isothermal AFM capable of the same measurements without the introduction of temperature gradients are described. The experimental results and thermal analysis described in this thesis have been published in the Journal of Applied Physics, "Temperature dependence of single-asperity friction for a diamond on diamondlike carbon interface", J. App. Phys., 107(11):114903, 2010.

  11. Sliding wear and friction behavior of zirconium alloy with heat-treated Inconel718

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.H., E-mail: kimjhoon@cnu.ac.kr [Dept. of Mechanical Design Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Park, J.M. [Dept. of Mechanical Design Engineering, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Park, J.K.; Jeon, K.L. [Nuclear Fuel Technology Department, Korea Nuclear Fuel, 1047 Daedukdae-ro, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

    2014-04-01

    In water-cooled nuclear reactors, the sliding of fuel rod can lead to severe wear and it is an important issue to sustain the structural integrity of nuclear reactor. In the present study, sliding wear behavior of zirconium alloy in dry and water environment using Pin-On-Disk sliding wear tester was investigated. Wear resistance of zirconium alloy against heat-treated Inconel718 pin was examined at room temperature. Sliding wear tests were carried out at different sliding distance, axial load and sliding speed based on ASTM (G99-05). The results of these experiments were verified with specific wear rate and coefficient of friction. The micro-mechanisms responsible for wear in zirconium alloy were identified to be microcutting and microcracking in dry environment. Moreover, micropitting and delamination were observed in water environment.

  12. Antiwear and reducing friction performance of (2-sulphurone-benzothiazole)-3-methyl dodecanoate

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A heterocyclic derivative of (2-sulphurone-benzothiazole)-3-methyl dodecanoate was synthesized. Its tribological performance when added to liquid paraffin was evaluated on a four-ball tester and a ring-on-block machine. Results indicate that compared with the base oil the wear resistance and load-carrying capacities of the oil with novel additive are improved, and the friction coefficient is decreased. There is an optimal content of the novel compound, at which the corresponding oil gives the highest maximum non-seizure load. Above the content, the load carrying capacity of the oil is not increased but decreased. The nature of the film formed on the rubbed surface was investigated by X-ray photoelectron spectroscopy (XPS) analysis, and the action mechanism of the novel compound was discussed.

  13. MorphoTester: An Open Source Application for Morphological Topographic Analysis.

    Science.gov (United States)

    Winchester, Julia M

    2016-01-01

    The increased prevalence and affordability of 3D scanning technology is beginning to have significant effects on the research questions and approaches available for studies of morphology. As the current trend of larger and more precise 3D datasets is unlikely to slow in the future, there is a need for efficient and capable tools for high-throughput quantitative analysis of biological shape. The promise and the challenge of implementing relatively automated methods for characterizing surface shape can be seen in the example of dental topographic analysis. Dental topographic analysis comprises a suite of techniques for quantifying tooth surfaces and component features. Topographic techniques have provided insight on mammalian molar form-function relationships and these methods could be applied to address other topics and questions. At the same time implementing multiple complementary topographic methods can have high time and labor costs, and comparability of data formats and approaches is difficult to predict. To address these challenges I present MorphoTester, an open source application for visualizing and quantifying topography from 3D triangulated polygon meshes. This application is Python-based and is free to use. MorphoTester implements three commonly used dental topographic metrics-Dirichlet normal energy, relief index, and orientation patch count rotated (OPCR). Previous OPCR algorithms have used raster-based grid data, which is not directly interchangeable with vector-based triangulated polygon meshes. A 3D-OPCR algorithm is provided here for quantifying complexity from polygon meshes. The efficacy of this metric is tested in a sample of mandibular second molars belonging to four species of cercopithecoid primates. Results suggest that 3D-OPCR is at least as effective for quantifying complexity as previous approaches, and may be more effective due to finer resolution of surface data considered here. MorphoTester represents an advancement in the automated

  14. SURFACE DYNAMIC FRICTION OF POLYMER GELS

    Institute of Scientific and Technical Information of China (English)

    J.P.Gong; G.Kagata; Y.Iwasaki; Y.Osada

    2000-01-01

    The sliding friction of various kinds of hydrogels has been studied and it was found that the frictional behaviors of the hydrogels do not conform to Amonton's law F =μW which well describes the friction of solids. The frictional force and its dependence on the load are quite different depending on the chemical structures of the gels, surface properties of the opposing substrates, and the measurement condition. The gel friction is explained in terms of interfacial interaction, either attractive or repulsive, between the polymer chain and the solid surface. According to this model, the friction is ascribed to the viscous flow of solvent at the interface in the repulsive case. In the attractive case, the force to detach the adsorbing chain from the substrate appears as friction. The surface adhesion between glass particles and gels measured by AFM showed a good correlation with the friction, which supported the repulsion-adsorption model proposed by the authors.

  15. The Friction of Saline Ice on Aluminium

    Directory of Open Access Journals (Sweden)

    Christopher Wallen-Russell

    2016-01-01

    Full Text Available The friction of ice on other materials controls loading on offshore structures and vessels in the Arctic. However, ice friction is complicated, because ice in nature exists near to its melting point. Frictional heating can cause local softening and perhaps melting and lubrication, thus affecting the friction and creating a feedback loop. Ice friction is therefore likely to depend on sliding speed and sliding history, as well as bulk temperature. The roughness of the sliding materials may also affect the friction. Here we present results of a series of laboratory experiments, sliding saline ice on aluminium, and controlling for roughness and temperature. We find that the friction of saline ice on aluminium μice-al=0.1 typically, but that this value varies with sliding conditions. We propose physical models which explain the variations in sliding friction.

  16. Simple Rheological Analysis Method of Spinnable-Polymer Flow Properties Using MFI Tester

    Directory of Open Access Journals (Sweden)

    Basel Younes

    2015-01-01

    Full Text Available Rheological characterization of polymers explains the flow behaviour and viscoelastic properties and tests fibre-forming ability. The current method investigates the viscoelastic properties and morphology of polymers and finds the rheological data and the right polymer viscosity, which is determining the best processing temperature. The right processing temperature saves the power, the material, and the time needed for production. After calculating polymers viscosity by using MFI tester, the method investigates rheological properties and surface shape at different temperatures and loads. The method could apply to other polymers to find the viscosity-temperature change and to set the best processing temperature.

  17. The Influence of Indenter Rotation Angle on The Quality of Vicker Tester Calibration

    Directory of Open Access Journals (Sweden)

    Jozef Petrík

    2011-10-01

    Full Text Available The object of submitted work is to analyze the influence of the rotation of the indenter (diamond pyramid and test force on the result of Vickers hardness tester calibration using uncertainty analysis, Measurement systems analysis (MSA, analysis of variance (ANOVA and Z-score. The rotation anmgle of indenter affects the values of hardness, repeatability rrel, maximal error Erel and relative expanded uncertainty Urel. The significance of the angle of indenter on the hardness and observed parameters of calibration no such as it of test force, but not negligible.

  18. The Influence of Indenter Rotation Angle on The Quality of Vicker Tester Calibration

    Directory of Open Access Journals (Sweden)

    Jozef Petrík

    2011-10-01

    Full Text Available The object of submitted work is to analyze the influence of the rotation of the indenter (diamond pyramid and test force on the result of Vickers hardness tester calibration using uncertainty analysis, Measurement systems analysis (MSA, analysis of variance (ANOVA and Z-score.  The rotation anmgle of  indenter affects the values of hardness, repeatability rrel, maximal error Erel and relative expanded uncertainty Urel. The significance of the angle of indenter on the hardness and observed parameters of calibration no such as it of test force, but not negligible.

  19. STS-44 Pilot Henricks uses Visual Function Tester (VFT) on OV-104's middeck

    Science.gov (United States)

    1991-01-01

    STS-44 Pilot Terence T. Henricks tests his visual acuity with the Visual Function Tester 1 (VFT-1) on the middeck of Atlantis, Orbiter Vehicle (OV) 104. VFT-1 measures changes in the vision of an astronaut in microgravity. It is a hand-held, battery-powered device with a binocular eyepiece that uses controlled illumination to present a variety of visual targets for testing primarily visual acuity and eye interaction effects, such as stereopsis and eye dominance. This experiment is being conducted in conjunction with the Military Man in Space activities.

  20. Monolith filter apparatus and membrane apparatus, and method using same

    Energy Technology Data Exchange (ETDEWEB)

    Goldsmith, Robert L [Wayland, MA

    2012-04-03

    A filtration apparatus that separates a liquid feedstock mixed with a gas into filtrate and retentate, the apparatus including at least one filtration device comprised of at least one monolith segment of porous material that defines a plurality of passageways extending longitudinally from a feed face of the structure to a retentate end face. The filtration device contains at least one filtrate conduit within it for carrying filtrate toward a filtrate collection zone, the filtrate conduit providing a path of lower flow resistance than that of alternative flow paths through the porous material of the device. The filtration device can also be utilized as a membrane support for a device for microfiltration, ultrafiltration, nanofiltration, reverse osmosis, or pervaporation. Also disclosed is a method for using such a filtration apparatus.

  1. Coordination Frictions and Job Heterogeneity

    DEFF Research Database (Denmark)

    Kennes, John; le Maire, Christian Daniel

    This paper develops and extends a dynamic, discrete time, job to worker matching model in which jobs are heterogeneous in equilibrium. The key assumptions of this economic environment are (i) matching is directed and (ii) coordination frictions lead to heterogeneous local labor markets. We de- rive...

  2. Frictional heating of tribological contacts

    NARCIS (Netherlands)

    Bos, Johannes

    1995-01-01

    Wherever friction occurs, mechanical energy is transformed into heat. The tem­ perature rise associated with this heating can have an important influence on the tribological behaviour of the contacting components. Apart from determining per­ formance, thermal phenomena affect reliability and may cau

  3. Friction Sensitivity of Primary Explosives

    Science.gov (United States)

    1982-09-01

    potassium dinitrobenzofuroxan none tetrazene 407913 tetrazene 7902454 The mixes which were tested are: NOL 130 (basic lead styphnate , barium nitrate, lead...azide, tetrazene, and antimony sulfide); PA 100 (normal lead styphnate , barium nitrate, tetrazene, lead dioxide, calcium silicide, and antimony...styuhnate, basic lead styphnate , potassium dinitrobenzofuroxan, and tetrazene were tested to determine the- 10% and 50% probability of friction

  4. Friction of atomically stepped surfaces

    Science.gov (United States)

    Dikken, R. J.; Thijsse, B. J.; Nicola, L.

    2017-03-01

    The friction behavior of atomically stepped metal surfaces under contact loading is studied using molecular dynamics simulations. While real rough metal surfaces involve roughness at multiple length scales, the focus of this paper is on understanding friction of the smallest scale of roughness: atomic steps. To this end, periodic stepped Al surfaces with different step geometry are brought into contact and sheared at room temperature. Contact stress that continuously tries to build up during loading, is released with fluctuating stress drops during sliding, according to the typical stick-slip behavior. Stress release occurs not only through local slip, but also by means of step motion. The steps move along the contact, concurrently resulting in normal migration of the contact. The direction of migration depends on the sign of the step, i.e., its orientation with respect to the shearing direction. If the steps are of equal sign, there is a net migration of the entire contact accompanied by significant vacancy generation at room temperature. The stick-slip behavior of the stepped contacts is found to have all the characteristic of a self-organized critical state, with statistics dictated by step density. For the studied step geometries, frictional sliding is found to involve significant atomic rearrangement through which the contact roughness is drastically changed. This leads for certain step configurations to a marked transition from jerky sliding motion to smooth sliding, making the final friction stress approximately similar to that of a flat contact.

  5. Rotary Engine Friction Test Rig Development Report

    Science.gov (United States)

    2011-12-01

    5  4.  Friction Rig Development 7  5.  AutoCAD ...Figure 4. Engine friction test rig AutoCAD model. ........................................................................8  Figure 5. Engine...top dead center. 8 5. AutoCAD Model Development A model of the rotary engine friction test rig was developed to determine the optimal

  6. Asbestos free friction composition for brake linings

    Indian Academy of Sciences (India)

    Arnab Ganguly; Raji George

    2008-02-01

    An asbestos free friction material composite for brake linings is synthesized containing fibrous reinforcing constituents, friction imparting and controlling additives, elastomeric additives, fire retarding components and a thermosetting resin. The composite shows exemplary friction characteristics and has great resistance to wear and shows good temperature stability.

  7. Multiscale friction modeling for sheet metal forming

    NARCIS (Netherlands)

    Hol, J.; Cid Alfaro, M.V.; de Rooij, Matthias B.; Meinders, Vincent T.; Felder, Eric; Montmitonnet, Pierre

    2010-01-01

    The most often used friction model for sheet metal forming simulations is the relative simple Coulomb friction model. This paper presents a more advanced friction model for large scale forming simulations based on the surface change on the micro-scale. The surface texture of a material changes when

  8. A thermodynamic model of sliding friction

    Directory of Open Access Journals (Sweden)

    Lasse Makkonen

    2012-03-01

    Full Text Available A first principles thermodynamic model of sliding friction is derived. The model predictions are in agreement with the observed friction laws both in macro- and nanoscale. When applied to calculating the friction coefficient the model provides a quantitative agreement with recent atomic force microscopy measurements on a number of materials.

  9. Analysis of the moment caused by friction of cardan joint. Cardan joint no friction kishinryoku kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Ono, K.; Yagi, Shida, T. (Atsugi Unisia Corp., Kanagawa (Japan))

    1990-10-01

    Analyzing the vibromotive force, generated by the friction, in generation morphology, level, dynamical characteristics, etc., through measurement of joint unit friction simulation of frictional vibromotive force and on-platform measurement of propeller shaft in vibromotive force, the present report investigated the influence of friction on the vehicle in sound vibration performance. By a vibromotive force measurement system, internally equipped with a piezoelectric type force meter, frictional vibromotive force could be quantitatively grasped. The friction must be appropriately controlled, because the moment, generated by it, is expected to be put in the vehicle by intermediation of a supporting point and adversely influence the sound vibration performance. Apart from the above, elucidation was made of relation between the ordinal number components of rotation of vibromotive force and friction, calculation of reaction force at the supporting point by the frictional measurement, relation between the joint angle and frictional vibromotive force, second couple force due to the friction, etc. 3 refs., 15 figs.

  10. Bio-inspired enhancement of friction and adhesion at the polydimethylsiloxane-intestine interface and biocompatibility characterization.

    Science.gov (United States)

    Zhang, Hongyu; Wang, Yi; Vasilescu, Steven; Gu, Zhibin; Sun, Tao

    2017-05-01

    An active navigation of self-propelled miniaturized robot along the intestinal tract without injuring the soft tissue remains a challenge as yet. Particularly in this case an effective control of the interfacial friction and adhesion between the material used and the soft tissue is crucial. In the present study, we investigated the frictional and adhesive properties between polydimethylsiloxane (PDMS, microscopically patterned with micro-pillar arrays and non-patterned with a flat surface) and rabbit small intestinal tract using a universal material tester. The friction coefficient-time plot and adhesive force-time plot were recorded during the friction test (sliding speed: 0.25mm/s; normal loading: 0.4N) and adhesion test (preloading: 0.5N; hoisting speed: 2.5×10(-3)mm/s). In addition, biocompatibility of the PDMS samples was characterized in terms of cell morphology (scanning electron microscope) and cell cytotoxicity (alamarBlue assay) using human vascular endothelial cells (HUVECs). The results demonstrated that the interfacial friction (0.27 vs 0.19) and adhesion (34.9mN vs 26.7mN) were greatly increased using microscopically patterned PDMS, in comparison with non-patterned PDMS. HUVECs adhered to and proliferated on non-patterned/microscopically patterned PDMS very well, with a relative cell viability of about 90% following seeding at 1d, 3d, and 5d. The favorable enhancement of the frictional and adhesive properties, along with the excellent biocompatibility of the microscopically patterned PDMS, makes it a propitious choice for clinical application of self-propelled miniaturized robots. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Tribological Properties of AlSi17Cu5Mg Alloy Modified with CuP Master Alloy with Various Speeds of Friction

    OpenAIRE

    Piątkowski J.; Wieszała R.

    2016-01-01

    The paper presents the influence of modification with phosphorus (CuP10) on the tribological properties of the alloy AlSi17Cu5Mg coupled abrasively with cast-iron EN GJL-350. Tests of coefficient of friction and wear of mass were conducted on tribological tester T-01. An important aspect in the assessment of the tribological properties is the analysis of initial material microstructure in reference to silumin which underwent modification with phosphorus. It was found that the difference in st...

  12. Oil recovery apparatus and method

    Energy Technology Data Exchange (ETDEWEB)

    Lowe, J.G.

    1981-05-19

    An oil recovery apparatus and method, particularly for removing oil and grease from the discharge of dishwashing machines or the like, provides a small size assembly employing the same principle as in U.S. Pat. No. 4,051,024. This apparatus and method employs single rotating discs of plastic or plastic coated material and each disk has a pair of scraper blades arranged to scrape opposite sides of the rotating blade. Exterior of the container for the oil recovery apparatus is at least one filter basket adapted to receive the flow into the strainer container of large particles of food and other waste such as cigarette butts and the like. Each filter is disposed for the ready cleaning of accumulated matter from the basket. There is shown plural filters, valve controls, auxiliary heating and disc support means to be more fully described.

  13. Comparison of the frictional resistance between archwire and different bracket system: An in vitro study

    Directory of Open Access Journals (Sweden)

    Ajith R Pillai

    2014-01-01

    Full Text Available Background and Objectives: The purpose of this study is to evaluate the frictional resistance generated by conventional stainless steel, radiance ceramic bracket, self-ligating and composite brackets using a 0.019 × 0.025 stainless steel straight length wires in a 022 slot and to select brackets based on their frictional characteristic. Methodology: In order to conduct this study, four different types of bracket system were selected of the mclaughlin-bennet-trevesi (MBT discipline. They are Group 1 - stainless steel, Group 2 - composite bracket Group 3 - (American Orthodontics radiance ceramic bracket Group 4 - self-ligating bracket (SLB (Empower. In this study, five maxillary brackets of an arch of each type were used. All brackets are 0.022 × 0.028" in preadjusted edgewise appliance which simulates the dental arch. Five brackets were bonded to a stainless steel bar of dimension 150 mm × 25 mm × 3 mm. The bracket-arch wire units were submitted to mechanical test with an Instron universal testing machine 3365. A testing apparatus or holding jig was designed to hold the bracket during the mechanical test. Each sample was pulled at a speed of 6 mm for 1 min. Descriptive statistical information including mean and standard deviation of maximum friction force was calculated for each bracket wire combination. Interpretation and Conclusion: The SLB has the least friction among the four groups. The ceramic bracket showed the highest friction followed by stainless steel bracket, composite bracket, and SLB.

  14. [Design of the psychology tester based on ZigBee technology].

    Science.gov (United States)

    Zhong, Tianping; Tang, Liming

    2012-09-01

    To design a psychological state tester based on ZigBee wireless technology. Through analog circuit preprocessing, the heartbeat collected by the pulse sensor will be transformed into digital signal from analog signal, and then can be processed and displayed after transported to the personal computer through the Zigbee wireless communicate units. The data will be retrieval and playback for the measurement of psychology. The experiments show that the device is able to acquire the pulse wave of the human body in real-time, at the same time, through the ZigBee wireless network, it can accomplish real-time, secure and reliable communications, and it also can be used in the research of testing the mental state of the individual. Through the application of the ZigBee communicate technology; the psychology tester can collect the pulse signal to reflect the individual's mental state in different conditions. So it will be applicable to a wide range of psychology measurement and other areas.

  15. Combining Ability in Wheat for Seedling Traits by Line X Tester Analysis Under Saline Conditions

    Directory of Open Access Journals (Sweden)

    Muhammad Osaf

    Full Text Available A line × tester analysis involving five varieties SQ-26, SQ-77, GH-10, 8670, PARC-N2 (lines and three varieties 8721, SARC-5 and DN-4 (testers were crossed to study some hydroponics growing characters. In controlled conditions SQ-26 exhibited the highest positive GCA effects on Shoot length, Shoot fresh weight, Na+ and K+ concentrations, while SQ-77 showed maximum GCA effects on Root length, Root fresh weight and Shoot dry weight in females and in males and both DN-4 and SARC-5 showed the highest GCA effects. Under high saline concentration female SQ-77 showed the maximum positive effects on all characters but on shoot length and Na concentration while male SARC-5 exhibited the highest positive GCA effects on all characters. Under high saline level, the cross combination SQ-26 × 8721 showed SCA effects for shoot length, whereas 8670 x 8721 showed the same effects for shoot fresh weight, root fresh weight and root dry weight. For Na+ and K+ concentrations, the cross combination GH-10 × DN-4 showed then highest SCA effects, whereas for shoot dry weight and root length, the cross combinations GH-10 × SARC-5 and PARC-N2 × 8721 showed the highest SCA effects, respectively.

  16. Self-adaptive surface texture design for friction reduction across the lubrication regimes

    Science.gov (United States)

    Hsu, Stephen M.; Jing, Yang; Zhao, Fei

    2016-03-01

    Surface texturing has been shown to reduce friction and improve durability in mechanical face seals and metal forming operations, and lightly loaded thrust bearings. However, the success has been limited to conformal contacts and low load high speed operating conditions, i.e. hydrodynamic lubrication dominated regime. Both experiments and numerical simulations have shown that textural patterns, under higher loading and/or slower speeds may increase friction and even cause the lubrication film collapse. Specific designs of surface texture pattern, as its shape, depth and density, are required for different lubrication regimes. Our own study has shown (Hsu et al 2014 J. Phys. D: Appl. Phys. 47 335307) that large/shallow dimple reduces friction in hydrodynamic lubrication regime, whereas small/deep dimple shows benefit in mixed/boundary lubrication regimes (if the textural designs can provides hydrodynamic/hydrostatic lift forces to reduce the machine loading). In considering an engine component typically experiences duty cycles that may cross various lubrication regimes, a multiscale surface texture design appears attractive. This type of mixed shape texturing combines textures designed for low load, high speed operating conditions and the textures that are designed for high load, low speed operations. In this paper, two types of multiscale surface texture designs are presented. Ball-on-three-flats (BOTF) wear tester (under high loading conditions) is used to evaluate the performance of these multiscale texture designs along with the baselines of un-textured surfaces under the same surface preparation procedures. Two texture designs with only a single shape dimples are included in the study. Results suggest that multiscale surface texture design not only further reduces friction in comparison to the textures with single shape dimples, but also shows the effectiveness across hydrodynamic regimes to the mixed lubrication regimes.

  17. A simple Cavendish experimental apparatus

    Science.gov (United States)

    Kossler, W. J.; Klein, Susann; Morrow, Dominick; Juliao, Andre

    2016-03-01

    A simple Cavendish apparatus is described that allows measurement of the gravitational constant G and makes observable the gravitational attraction between commonplace objects. The apparatus consists of a torsion balance constructed from readily available materials, including lead bricks and fishing weights ("sinkers"). A computer program is used to determine the gravitational field at the location of the small mass due to a nearby lead brick, which allows students to gain experience with numerical methods. Experimental results obtained are compatible with the accepted value of G.

  18. Design of simplified RLC Bridge Tester%简易RLC电桥测试仪的设计

    Institute of Scientific and Technical Information of China (English)

    朱赣; 徐云龙; 李伟明

    2012-01-01

    RLC测试是电子专业高素质技能型人才培养的一项内容。以AT89S51单片机作为核心控制器件,将电桥电路中的RLC电压参数经过运算放大器放大后进行模数转换,再由单片机处理数据后,RLC测量值液晶显示。%RLC testing is a part of highly skilled electronic professional training. The paper introduces the de- sign of a simplified RLC bridge tester which uses the AT89S51 microcontroller as the core control device. The tester amplifies the bridge voltage of the RLC circuit parameters through the operational amplifier then does the analog - digital conversion, then after the data processing by the mierocontroller; RLC tester liquid crystal screen can display the results.

  19. Effects of nano-LaF3 on the friction and wear behaviors of PTFE-based bonded solid lubricating coatings under different lubrication conditions

    Science.gov (United States)

    Jia, Yulong; Wan, Hongqi; Chen, Lei; Zhou, Huidi; Chen, Jianmin

    2016-09-01

    Influence of nanometer lanthanum fluoride (nano-LaF3) on the tribological behaviors of polytetrafluoroethylene (PTFE) bonded solid lubricating coatings were investigated using a ring-on-block friction-wear tester under dry friction and RP-3 jet fuel lubrication conditions. The worn surfaces and transfer films formed on the counterpart steel rings were observed by scanning electron microscope (SEM) and optical microscope (OM), respectively. The microstructures of the nano-LaF3 modified coatings and the distribution states of nano-LaF3 were studied by field-emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM), respectively. The results show that incorporation of nano-LaF3 improves the microhardness and the friction-reduced and anti-wear abilities of PTFE bonded solid lubricating coatings. The wear life of the modified coating is about 6 times longer than that of the coating without nano-LaF3 filler at a relatively low applied load (200 N) and rotary speed (1000 rev/min) under dry friction condition. The friction coefficient and wear life of the modified coating decrease with increase of applied load under dry friction, but the friction coefficient has hardly any variation and wear life decreases under RP-3 jet fuel lubrication condition. In addition, the friction coefficient of the modified coating reduces with the rotary speed increasing under dry sliding but has little change under RP-3 lubrication, the wear life increases firstly and then decreases. The results indicated that the wear failure mechanism is dominated by applied load, which plays an important role in guidance of application of nano-LaF3 modified PTFE bonded coating under different working environment.

  20. Friction properties and deformation mechanisms of halite(-mica) gouges from low to high sliding velocities

    Science.gov (United States)

    Buijze, Loes; Niemeijer, André R.; Han, Raehee; Shimamoto, Toshihiko; Spiers, Christopher J.

    2017-01-01

    The evolution of friction as a function of slip rate is important in understanding earthquake nucleation and propagation. Many laboratory experiments investigating friction of fault rocks are either conducted in the low velocity regime (10-8-10-4 ms-1) or in the high velocity regime (0.01-1 m s-1). Here, we report on the evolution of friction and corresponding operating deformation mechanisms in analog gouges deformed from low to high slip rates, bridging the gap between these low and high velocity regimes. We used halite and halite-muscovite gouges to simulate processes, governing friction, active in upper crustal quartzitic fault rocks, at conditions accessible in the laboratory. The gouges were deformed over a 7 orders of magnitude range of slip rate (10-7-1 m s-1) using a low-to-high velocity rotary shear apparatus, using a normal stress of 5 MPa and room-dry humidity. Microstructural analysis was conducted to study the deformation mechanisms. Four frictional regimes as a function of slip rate could be recognized from the mechanical data, showing a transitional regime and stable sliding (10-7-10-6 m s-1), unstable sliding and weakening (10-6-10-3 m s-1), hardening (10-2-10-1 m s-1) and strong weakening (10-1-1 m s-1). Each of the four regimes can be associated with a distinct microstructure, reflecting a transition from mainly brittle deformation accompanied by pressure solution healing to temperature activated deformation mechanisms. Additionally, the frictional response of a sliding gouge to a sudden acceleration of slip rate to seismic velocities was investigated. These showed an initial strengthening, the amount of which depended on the friction level at which the step was made, followed by strong slip weakening.

  1. Fabrication of a rotary carbon nanotube bearing test apparatus

    Science.gov (United States)

    Cook, E. H.; Weinberg, M. S.; Spakovszky, Z. S.; Carter, D. J. D.

    2015-12-01

    Carbon Nanotubes (CNTs) are attractive elements for bearings in Micro-Electro-Mechanical Systems (MEMS), because their structure comprises nested shells with no bonding and sub-nanometre spacing between them, enabling relative motion with low friction and wear. A reliable bearing technology is critical to bringing rotating MEMS machines from laboratory demonstrations to common use. We report here the design and fabrication of a test rotor, a testing apparatus and testing attempts, and integration of CNTs with MEMS. The device improves on existing CNT bearing demonstrators by establishing a vertical bearing orientation (enabling superior rotor balance and speed, and drive mechanism placement flexibility) and a manufacturable process (employing CNTs grown in place by chemical vapour deposition (CVD)). The main outstanding challenge to demonstrating rotation is available CVD CNT quality.

  2. Transition from frictional to viscous deformation in granitoid fault rocks

    Science.gov (United States)

    Peč, M.; Heilbronner, R.; Stünitz, H.

    2009-04-01

    Fracturing of rocks in natural fault zones increases the permeability and produces extremely small grain sizes (jackets. Before deformation, the gouge material needs to be compacted. This is achieved by a set 1 of frictional deformation experiments at different temperatures (T = 24 °C, 300 °C, 500 °C, Pc = 500 MPa, strain rate = 10ˆ-4) to shear strains of approximately gamma = 2.5. In the subsequent experiments (set 2), potential viscous deformation processes are tested in the pre-deformed gouge. After initial frictional deformation (set 1) the samples are left at peak differential stress conditions for one week. Finally, in a third type of experiments (set 3), the peak differential stress was lowered after frictional deformation to a level similar to the confining pressure and held constant for one week. In set 1, the peak shear stresses are temperature independent (given the limited stress resolution of the Griggs apparatus; 300° C = 780 - 870 MPa, 500° C = 760 - 820 MPa). In set 2, the stress relaxation after frictional deformation is clearly temperature dependent (after one week at 300° C, the shear stress is approx. 370 MPa; at 500° C, approx. 230 MPa). In set 3, no creep was observed. Further investigation of this phenomenon is required but probably the differential stress was too low. Microstructural observations show a striking difference between samples of set 1 and set 2. The samples deformed by initial friction only (set 1) show angular clasts and many small grains. The grain size distribution is similar to that observed in natural gouge material from seismic faults and to experimentally cracked granitoid material (Keulen et al. 2007, Heilbronner and Keulen 2006). In the creep-deformed samples (set 2), we observe the disappearance of the grains of < 0.1 μm size, cementation of individual grains into larger ones, and lobate grain boundaries in rounded clasts. Thus, solution - precipitation processes have taken place in creep experiments of

  3. Magnetic separation apparatus and methods

    NARCIS (Netherlands)

    Tibbe, Arjan; Scholtens, Tycho M.; Terstappen, Leon W.M.M.

    2010-01-01

    Apparatuses and methods for separating, immobilizing, and quantifying biological substances from within a fluid medium. Biological substances are observed by employing a vessel (6) having a chamber therein, the vessel comprising a transparent collection wall (5). A high internal gradient magnetic ca

  4. Extended range chemical sensing apparatus

    Science.gov (United States)

    Hughes, Robert C.; Schubert, W. Kent

    1994-01-01

    An apparatus for sensing chemicals over extended range of concentrations. In particular, first and second sensors each having separate, but overlapping ranges for sensing concentrations of hydrogen are provided. Preferably, the first sensor is a MOS solid state device wherein the metal electrode or gate is a nickel alloy. The second sensor is a chemiresistor comprising a nickel alloy.

  5. The ALPHA antihydrogen trapping apparatus

    Science.gov (United States)

    Amole, C.; Andresen, G. B.; Ashkezari, M. D.; Baquero-Ruiz, M.; Bertsche, W.; Bowe, P. D.; Butler, E.; Capra, A.; Carpenter, P. T.; Cesar, C. L.; Chapman, S.; Charlton, M.; Deller, A.; Eriksson, S.; Escallier, J.; Fajans, J.; Friesen, T.; Fujiwara, M. C.; Gill, D. R.; Gutierrez, A.; Hangst, J. S.; Hardy, W. N.; Hayano, R. S.; Hayden, M. E.; Humphries, A. J.; Hurt, J. L.; Hydomako, R.; Isaac, C. A.; Jenkins, M. J.; Jonsell, S.; Jørgensen, L. V.; Kerrigan, S. J.; Kurchaninov, L.; Madsen, N.; Marone, A.; McKenna, J. T. K.; Menary, S.; Nolan, P.; Olchanski, K.; Olin, A.; Parker, B.; Povilus, A.; Pusa, P.; Robicheaux, F.; Sarid, E.; Seddon, D.; Seif El Nasr, S.; Silveira, D. M.; So, C.; Storey, J. W.; Thompson, R. I.; Thornhill, J.; Wells, D.; van der Werf, D. P.; Wurtele, J. S.; Yamazaki, Y.

    2014-01-01

    The ALPHA collaboration, based at CERN, has recently succeeded in confining cold antihydrogen atoms in a magnetic minimum neutral atom trap and has performed the first study of a resonant transition of the anti-atoms. The ALPHA apparatus will be described herein, with emphasis on the structural aspects, diagnostic methods and techniques that have enabled antihydrogen trapping and experimentation to be achieved.

  6. Apparatus for measuring fluid flow

    Science.gov (United States)

    Smith, J.E.; Thomas, D.G.

    Flow measuring apparatus includes a support loop having strain gages mounted thereon and a drag means which is attached to one end of the support loop and which bends the sides of the support loop and induces strains in the strain gages when a flow stream impacts thereon.

  7. Portable Pallet-Weighing Apparatus

    Science.gov (United States)

    Day, R. M.

    1983-01-01

    Portable apparatus intended for standard four-trunnion pallets readily adaptable to any large payload or other loads where shifting of cargo is to be avoided. Device lifts trunnion of pallet short distance above its resting place. Weight at trunnion applied to load cell. Similar units placed at all four trunnions.

  8. A FILTRATION METHOD AND APPARATUS

    DEFF Research Database (Denmark)

    2003-01-01

    The present invention concerns a method and an apparatus for separating dry matter from liquid, comprising providing an enclosed separation environment capable of being pressure regulated, and in said enclosed separation environment contacting at least one filter with a suspension accumulating dr...

  9. Feature Referenced Error Correction Apparatus.

    Science.gov (United States)

    A feature referenced error correction apparatus utilizing the multiple images of the interstage level image format to compensate for positional...images and by the generation of an error correction signal in response to the sub-frame registration errors. (Author)

  10. Measuring Apparatus for Coal Powder

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The measuring apparatus for coal powder, equipped with radioactive source, is a set of device andcan be used to measure the density in the pipes and cumulative consumed amount of coal powder in apower plant, and to examine and display the status of the coal powder input system. It is sketched asFig. 1.

  11. Material transport method and apparatus

    Science.gov (United States)

    Ramsey, J. Michael; Ramsey, Roswitha S.

    2000-01-01

    An electrospray apparatus uses a microchannel formed in a microchip. Fluid is pumped through the channel to an outlet orifice using either hydraulic or electrokinetic means. An electrospray is generated by establishing a sufficient potential difference between the fluid at the outlet orifice and a target electrode spaced from the outlet orifice. Electrokinetic pumping is also utilized to provide additional benefits to microchip devices.

  12. The ALPHA antihydrogen trapping apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Amole, C. [Department of Physics and Astronomy, York University, Toronto ON Canada, M3J 1P3 (Canada); Andresen, G.B. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Ashkezari, M.D. [Department of Physics, Simon Fraser University, Burnaby, BC Canada, V5A 1S6 (Canada); Baquero-Ruiz, M. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Bertsche, W. [Department of Physics, College of Science, Swansea University, Swansea SA2 8PP (United Kingdom); School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); The Cockcroft Institute, Warrington WA4 4AD (United Kingdom); Bowe, P.D. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Butler, E. [Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Capra, A. [Department of Physics and Astronomy, York University, Toronto ON Canada, M3J 1P3 (Canada); Carpenter, P.T. [Department of Physics, Auburn University, Auburn, AL 36849-5311 (United States); Cesar, C.L. [Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972 (Brazil); Chapman, S. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Charlton, M.; Deller, A.; Eriksson, S. [Department of Physics, College of Science, Swansea University, Swansea SA2 8PP (United Kingdom); Escallier, J. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Fajans, J. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Friesen, T. [Department of Physics and Astronomy, University of Calgary, Calgary AB, Canada, T2N 1N4 (Canada); Fujiwara, M.C.; Gill, D.R. [TRIUMF, 4004 Wesbrook Mall, Vancouver BC, Canada V6T 2A3 (Canada); Gutierrez, A. [Department of Physics and Astronomy, University of British Columbia, Vancouver BC, Canada V6T 1Z4 (Canada); and others

    2014-01-21

    The ALPHA collaboration, based at CERN, has recently succeeded in confining cold antihydrogen atoms in a magnetic minimum neutral atom trap and has performed the first study of a resonant transition of the anti-atoms. The ALPHA apparatus will be described herein, with emphasis on the structural aspects, diagnostic methods and techniques that have enabled antihydrogen trapping and experimentation to be achieved.

  13. High temperature skin friction measurement

    Science.gov (United States)

    Tcheng, Ping; Holmes, Harlan K.; Supplee, Frank H., Jr.

    1989-01-01

    Skin friction measurement in the NASA Langley hypersonic propulsion facility is described. The sensor configuration utilized an existing balance, modified to provide thermal isolation and an increased standoff distance. For test run times of about 20 sec and ambient-air cooling of the test section and balance, the modified balance performed satisfactorily, even when it was subjected to acoustic and structural vibration. The balance is an inertially balanced closed-loop servo system where the current to a moving-coil motor needed to restore or null the output from the position sensor is a measure of the force or skin friction tending to displace the moving element. The accuracy of the sensor is directly affected by the position sensor in the feedback loop, in this case a linear-variable differential transformer which has proven to be influenced by temperature gradients.

  14. Measuring Coefficients of Friction for Materials Commonly Used in Theatre

    Science.gov (United States)

    Mentzer, Robert; Martell, Eric

    2008-04-01

    While designing a stage setup for a theatrical presentation, designers must consider equipment, materials, cost and manpower, and we can use physics to simplify and enhance the process. Unfortunately, there is a lack of information about the properties of materials commonly used in theatre. The objective of this research was to determine the coefficients of static and kinetic friction for several materials commonly used in theatrical scene construction and the coefficients of rolling friction for a series of commonly used casters. Materials of known coefficients were tested to confirm the accuracy of the experimental process. Data was collected using a sled style apparatus and LabVIEW software. Data was analyzed in mass volumes using Microsoft Excel spreadsheets and macros. This research was performed as a part of the Physics of Theatre project, a joint collaboration between Millikin University and the University of Illinois at Urbana-Champaign, and was supported in part by Millikin, UIUC, and the United States Institute for Theatre Technology.

  15. Thermodynamic aspects of rock friction

    CERN Document Server

    Mitsui, Noa

    2013-01-01

    Rate- and state-dependent friction law for velocity-step tests is analyzed from a thermodynamic point of view. A simple macroscopic non-equilibrium thermodynamic model with a single internal variable reproduces instantaneous jump and relaxation. Velocity weakening appears as a consequence of a plasticity related nonlinear coefficient. Permanent part of displacement corresponds to plastic strain, and relaxation effects are analogous to creep in thermodynamic rheology.

  16. Fault rheology beyond frictional melting.

    Science.gov (United States)

    Lavallée, Yan; Hirose, Takehiro; Kendrick, Jackie E; Hess, Kai-Uwe; Dingwell, Donald B

    2015-07-28

    During earthquakes, comminution and frictional heating both contribute to the dissipation of stored energy. With sufficient dissipative heating, melting processes can ensue, yielding the production of frictional melts or "pseudotachylytes." It is commonly assumed that the Newtonian viscosities of such melts control subsequent fault slip resistance. Rock melts, however, are viscoelastic bodies, and, at high strain rates, they exhibit evidence of a glass transition. Here, we present the results of high-velocity friction experiments on a well-characterized melt that demonstrate how slip in melt-bearing faults can be governed by brittle fragmentation phenomena encountered at the glass transition. Slip analysis using models that incorporate viscoelastic responses indicates that even in the presence of melt, slip persists in the solid state until sufficient heat is generated to reduce the viscosity and allow remobilization in the liquid state. Where a rock is present next to the melt, we note that wear of the crystalline wall rock by liquid fragmentation and agglutination also contributes to the brittle component of these experimentally generated pseudotachylytes. We conclude that in the case of pseudotachylyte generation during an earthquake, slip even beyond the onset of frictional melting is not controlled merely by viscosity but rather by an interplay of viscoelastic forces around the glass transition, which involves a response in the brittle/solid regime of these rock melts. We warn of the inadequacy of simple Newtonian viscous analyses and call for the application of more realistic rheological interpretation of pseudotachylyte-bearing fault systems in the evaluation and prediction of their slip dynamics.

  17. Waste Water Treatment Apparatus and Methods

    Science.gov (United States)

    Littman, Howard (Inventor); Plawsky, Joel L. (Inventor); Paccione, John D. (Inventor)

    2014-01-01

    An improved draft tube spout fluid bed (DTSFB) mixing, handling, conveying, and treating apparatus and systems, and methods for operating are provided. The apparatus and systems can accept particulate material and pneumatically or hydraulically conveying the material to mix and/or treat the material. In addition to conveying apparatus, a collection and separation apparatus adapted to receive the conveyed particulate material is also provided. The collection apparatus may include an impaction plate against which the conveyed material is directed to improve mixing and/or treatment. The improved apparatus are characterized by means of controlling the operation of the pneumatic or hydraulic transfer to enhance the mixing and/or reacting by controlling the flow of fluids, for example, air, into and out of the apparatus. The disclosed apparatus may be used to mix particulate material, for example, mortar; react fluids with particulate material; coat particulate material, or simply convey particulate material.

  18. Friction characteristics of floppy disks

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This note presents the principle and structure of a tribological measure for floppy disks.The precision of the force measuring system is 1 mN in loading and 3×10-6 N in friction.The resolution of the film thickness between head and floppy disk is 0.5 nm in the vertical and 1.5 nm in the horizontal direction.In order to investigate the tribological characteristics of floppy disks,six types of floppy disks have been tested and the floating properties of these disks are also studied with film measuring system.The experimental results of the surface morphology and friction coefficient of these floppy disks using the atomic force microscope/friction force mcroscope (AFM/FFM) are in accordance with the conclusion made by our own measuring system.The experimental results show that the air film thickness between head and disk is of the same order as the surface roughness of floppy disks.

  19. Apparatus for assembly of microelectronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Okandan, Murat; Nielson, Gregory N.; Cruz-Campa, Jose Luis; Lavin, Judith Maria; Resnick, Paul J.

    2017-09-12

    An apparatus including a carrier substrate configured to move a microelectronic device. The apparatus further includes a rotatable body configured to receive the microelectronic device. Additionally, the apparatus includes a second substrate configured to receive the microelectronic device from the rotatable body.

  20. 49 CFR 236.590 - Pneumatic apparatus.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Pneumatic apparatus. 236.590 Section 236.590..., Train Control and Cab Signal Systems Inspection and Tests; Locomotive § 236.590 Pneumatic apparatus. Automatic train stop, train control, or cab signal pneumatic apparatus shall be inspected, cleaned, and the...

  1. Test Resource Partitioning Based on Efficient Response Compaction for Test Time and Tester Channels Reduction

    Institute of Scientific and Technical Information of China (English)

    Yin-He Han; Xiao-Wei Li; Hua-Wei Li; Anshuman Chandra

    2005-01-01

    This paper presents a test resource partitioning technique based on an efficient response compaction design called quotient compactor(q-Compactor). Because q-Compactor is a single-output compactor, high compaction ratios can be obtained even for chips with a small number of outputs. Some theorems for the design of q-Compactor are presented to achieve full diagnostic ability, minimize error cancellation and handle unknown bits in the outputs of the circuit under test (CUT). The q-Compactor can also be moved to the load-board, so as to compact the output response of the CUT even during functional testing. Therefore, the number of tester channels required to test the chip is significantly reduced. The experimental results on the ISCAS '89 benchmark circuits and an MPEG 2 decoder SoC show that the proposed compaction scheme is very efficient.

  2. Analyzing VLSI component test results of a GenRad GR125 tester

    Science.gov (United States)

    Zulaica, D.; Lee, C.-H.

    1995-06-01

    The GenRad GR125 VLSI chip tester provides tools for testing the functionality of entire chips. Test operation results, such as timing sensitivity or propagation delay, can be compared to published values of other manufacturers' chips. The tool options allow for many input vector situations to be tested, leaving the possibility that a certain test result has no meaning. Thus, the test operations are also analyzed for intent. Automating the analysis of test results can speed up the testing process and prepare results for processing by other tools. The procedure used GR125 test results of a 7404 Hex Inverter in a sample VHDL performance modeler on a Unix workstation. The VHDL code is simulated using the Mentor Graphics Corporation's Idea Station software, but should be portable to any VHDL simulator.

  3. Magnetic properties measurement of soft magnetic composite material (SOMALOY 700) by using 3-D tester

    Science.gov (United States)

    Asari, Ashraf; Guo, Youguang; Zhu, Jianguo

    2017-08-01

    Core losses of rotating electrical machine can be predicted by identifying the magnetic properties of the magnetic material. The magnetic properties should be properly measured since there are some variations of vector flux density in the rotating machine. In this paper, the SOMALOY 700 material has been measured under x, y and z- axes flux density penetration by using the 3-D tester. The calibrated sensing coils are used in detecting the flux densities which have been generated by the Labview software. The measured sensing voltages are used in obtaining the magnetic properties of the sample such as magnetic flux density B, magnetic field strength H, hysteresis loop which can be used to calculate the total core loss of the sample. The results of the measurement are analyzed by using the Mathcad software before being compared to another material.

  4. Design of versatile ASIC and protocol tester for CBM readout system

    Science.gov (United States)

    Zabołotny, W. M.; Byszuk, A. P.; Emschermann, D.; Gumiński, M.; Juszczyk, B.; Kasiński, K.; Kasprowicz, G.; Lehnert, J.; Müller, W. F. J.; Poźniak, K.; Romaniuk, R.; Szczygieł, R.

    2017-02-01

    Silicon Tracking System (STS), Muon Chamber (MUCH) and Transition Radiation Detector (TRD) subdetectors in the Compressed Baryonic Matter (CBM) detector system at Facility for Antiproton and Ion Research (FAIR) use the same innovative protocol ensuring reliable synchronization of the communication link between the controller and the front-end ASIC, transmission of time-deterministic commands to the ASIC and efficient readout of data. The paper describes the FPGA-based tester platform which can be used both for the verification of the protocol implementation in a front-end ASIC at the design stage, and for testing of the produced ASICs. Due to its modularity, the platform can be easily adapted for different integrated circuits and readout systems.

  5. Anti-wear and friction performance of ZrO2 nanoparticles as lubricant additive

    Institute of Scientific and Technical Information of China (English)

    Shiyu Ma; Shaohua Zheng; Duxia Cao; Hongna Guo

    2010-01-01

    The surface of ZrO2 nanoparticles was modified with silane coupling agent KH-560 by dispersing the nanoparticles in 20# machine oil.The tribological performance of the 20# machine oil with ZrO2 nanoparticles was evaluated by a four-ball tester and a thrust-ring machine.The loss of the thrust-ring weight was measured by an electronic balance with a precision of 0.0001 g.The worn surface was examined under a metallographic microscope with 400-times magnification.The results showed that the average friction coefficient decreased by 27.34%,and that the weight loss of the thrust-ring indicated no wear or nega-tive wear,the wear loss after six loads tests being-0.0163 g.The anti-wear(AW)and reducing friction(RF)abilities of the oil with ZrO2 nanoparticles addition were considerably improved,maximizing at an additive concentration of 0.5 wt%.

  6. Preparation of Ni-CNT composite coatings on aluminum substrate and its friction and wear behavior

    Institute of Scientific and Technical Information of China (English)

    涂江平; 朱丽萍; 陈卫祥; 赵新兵; 刘芙; 张孝彬

    2004-01-01

    Nickel-carbon nanotube(CNT) composite coatings with a Zn-Ni interlayer were prepared by electrodeposition technique on aluminum substrate. The effects of CNT concentration in plating bath on the volume fraction of CNTs in the deposits and the coating growth rate were investigated. The friction and wear behavior of the Ni-CNT composite coatings were examined using a pin-on-disk wear tester under dry sliding conditions at a sliding speed of 0. 062 3 m/s and load range from 12 N to 150 N. Because of the reinforcement of CNTs in the composite coatings, at lower applied loads, the wear resistance was improved with increasing volume fraction of CNTs. Since cracking and peeling occur on the worn surface, the wear rates of composite coatings with high volume fraction of CNTs increase rapidly at higher applied loads. The friction coefficient of the composite coatings decreases with the increasing volume fraction of CNTs due to the reinforcement and self-lubrication of CNTs.

  7. Analysis of self-repair films on friction surface lubricated with nano-Cu additive

    Institute of Scientific and Technical Information of China (English)

    LIU Qian; XU Yi; SHI Pei-jing; YU He-long; XU Bin-shi

    2005-01-01

    The surface modified nanocopper particles were prepared with chemical reduction method. The wear test was carried out on a T-11 ball-on-plate friction and wear tester made in Poland. The material of the upper sample was GCr15 and the counterpart was AISI-1045 steel. The morphologies of the worn surfaces of the samples were observed by optical microscope and scanning electron microscope, while the element distributions on the worn surfaces were determined by means of electron microprobe analysis. As the results, a film mainly made of Cu is formed on the worn surface. The film on the surface of the still upper sample is thicker than that formed on the revolving coun terpart. At the edge of the groove of the worn surface made by the milling before test there is Cu element observed obviously, but there is not any Cu element in the bottom of the groove. A possible action mechanism of the film is suggested. The friction movement can induce reactivity of the metal and continuously produce activation surface. It benefits the film formed by nano-Cu in lubricant on the worn surface. Hardness and modulus of nano-Cu films were successfully measured and analyzed by the nanoindentation instrument. The results show that the hardness and modulus of the films are lower than those of the initial surface.

  8. Effect of Load on Friction-Wear Behavior of HVOF-Sprayed WC-12Co Coatings

    Science.gov (United States)

    Yifu, Jin; Weicheng, Kong; Tianyuan, Sheng; Ruihong, Zhang; Dejun, Kong

    2017-07-01

    A WC-12Co coating was sprayed on AISI H13 hot work mold steel using a high-velocity oxygen fuel. The morphologies, phase compositions, and distributions of chemical elements of the obtained coatings were analyzed using a field emission scanning electron microscope, x-ray diffraction, and energy-dispersive spectroscope (EDS), respectively. The friction-wear behaviors under different loads were investigated using a reciprocating wear tester; the morphologies and distributions of the chemical elements of worn tracks were analyzed using a SEM and its configured EDS, respectively. The results show the reunited grains of WC are held together by the Co binder; the primary phases of the coating are WC, Co, and a small amount of W2C and W, owing to the oxidation and decarburization of WC. Inter-diffusion of Fe and W between the coating and the substrate is shown, which indicates a good coating adhesion. The values of the average coefficient of friction under the loads of 40, 80, and 120 N are 0.29, 0.31, and 0.49, respectively. The WC grains are pulled out of the coating during the sliding wear test, but the coating maintains its integrity, suggesting that the coating is intact and continuously protects the substrate from wearing.

  9. Novel in situ mechanical testers to enable integrated metal surface micro-machines.

    Energy Technology Data Exchange (ETDEWEB)

    Follstaedt, David Martin; de Boer, Maarten Pieter; Kotula, Paul Gabriel; Hearne, Sean Joseph; Foiles, Stephen Martin; Buchheit, Thomas Edward; Dyck, Christopher William

    2005-10-01

    The ability to integrate metal and semiconductor micro-systems to perform highly complex functions, such as RF-MEMS, will depend on developing freestanding metal structures that offer improved conductivity, reflectivity, and mechanical properties. Three issues have prevented the proliferation of these systems: (1) warpage of active components due to through-thickness stress gradients, (2) limited component lifetimes due to fatigue, and (3) low yield strength. To address these issues, we focus on developing and implementing techniques to enable the direct study of the stress and microstructural evolution during electrodeposition and mechanical loading. The study of stress during electrodeposition of metal thin films is being accomplished by integrating a multi-beam optical stress sensor into an electrodeposition chamber. By coupling the in-situ stress information with ex-situ microstructural analysis, a scientific understanding of the sources of stress during electrodeposition will be obtained. These results are providing a foundation upon which to develop a stress-gradient-free thin film directly applicable to the production of freestanding metal structures. The issues of fatigue and yield strength are being addressed by developing novel surface micromachined tensile and bend testers, by interferometry, and by TEM analysis. The MEMS tensile tester has a ''Bosch'' etched hole to allow for direct viewing of the microstructure in a TEM before, during, and after loading. This approach allows for the quantitative measurements of stress-strain relations while imaging dislocation motion, and determination of fracture nucleation in samples with well-known fatigue/strain histories. This technique facilitates the determination of the limits for classical deformation mechanisms and helps to formulate a new understanding of the mechanical response as the grain sizes are refined to a nanometer scale. Together, these studies will result in a science

  10. 16 CFR Figure 4 to Subpart A of... - Flooring Radiant Panel Tester Schematic Low Flux End, Elevation

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Flooring Radiant Panel Tester Schematic Low Flux End, Elevation 4 Figure 4 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS INTERIM SAFETY STANDARD FOR CELLULOSE INSULATION The...

  11. Glitch Game Testers: The Design and Study of a Learning Environment for Computational Production with Young African American Males

    Science.gov (United States)

    DiSalvo, Elizabeth Betsy

    2012-01-01

    The implementation of a learning environment for young African American males, called the Glitch Game Testers, was launched in 2009. The development of this program was based on formative work that looked at the contrasting use of digital games between young African American males and individuals who chose to become computer science majors.…

  12. Bulk CMOS VLSI Technology Studies. Part 5. The Design and Implementation of a High Speed Integrated Circuit Functional Tester.

    Science.gov (United States)

    2014-09-26

    169 7404 Inverter Test ...... ................ 171 7482 Binary Adder Test .... .............. .174 REFERENCES ......... ......................... 176...tests run on a 7404 HEX INVERTER and a 7482 2-BIT BINARY FULL ADDER , are presented in Appendix E, TEST RESULTS...RAM, a 7404 HEX INVERTER, and a 7482 2-BIT FULL ADDER . These results indicate that the functional tester operates according to the specifications

  13. Reliability of knee joint range of motion and circumference measurements after total knee arthroplasty: does tester experience matter?

    DEFF Research Database (Denmark)

    Jakobsen, Thomas Linding; Christensen, Malene; Christensen, Stine Sommer

    2010-01-01

    BACKGROUND AND PURPOSE: Two of the most utilized outcome measures to assess knee joint range of motion (ROM) and intra-articular effusion are goniometry and circumference, respectively. Neither goniometry nor circumference of the knee joint have been examined for both intra-tester and inter-teste...

  14. Friction and Wear in Timing Belt Drives

    Directory of Open Access Journals (Sweden)

    B. Stojanovic

    2010-09-01

    Full Text Available Timing belt tooth goes into contact with a drive pulley, stretched to the maximum, because of the previous tension. When the contact begins the peak of the belt tooth makes the contact with the outer surface of the pulley teeth. The process of the teeth entering into the contact zone is accompanied with the relative sliding of their side surfaces and appropriate friction force. The normal force value is changing with the parabolic function, which also leads to the changes of the friction force. The biggest value of the normal force and of the friction force is at the tooth root. Hollow between teeth and the tip of the pulley teeth are also in contact. Occasionally, the face surface of the belt and the flange are also in contact. The friction occurs in those tribomechanical systems, also. Values of these friction forces are lower compared with the friction force, which occurs at the teeth root.

  15. Static friction between rigid fractal surfaces.

    Science.gov (United States)

    Alonso-Marroquin, Fernando; Huang, Pengyu; Hanaor, Dorian A H; Flores-Johnson, E A; Proust, Gwénaëlle; Gan, Yixiang; Shen, Luming

    2015-09-01

    Using spheropolygon-based simulations and contact slope analysis, we investigate the effects of surface topography and atomic scale friction on the macroscopically observed friction between rigid blocks with fractal surface structures. From our mathematical derivation, the angle of macroscopic friction is the result of the sum of the angle of atomic friction and the slope angle between the contact surfaces. The latter is obtained from the determination of all possible contact slopes between the two surface profiles through an alternative signature function. Our theory is validated through numerical simulations of spheropolygons with fractal Koch surfaces and is applied to the description of frictional properties of Weierstrass-Mandelbrot surfaces. The agreement between simulations and theory suggests that for interpreting macroscopic frictional behavior, the descriptors of surface morphology should be defined from the signature function rather than from the slopes of the contacting surfaces.

  16. Friction coefficient dependence on electrostatic tribocharging

    Science.gov (United States)

    Burgo, Thiago A. L.; Silva, Cristiane A.; Balestrin, Lia B. S.; Galembeck, Fernando

    2013-08-01

    Friction between dielectric surfaces produces patterns of fixed, stable electric charges that in turn contribute electrostatic components to surface interactions between the contacting solids. The literature presents a wealth of information on the electronic contributions to friction in metals and semiconductors but the effect of triboelectricity on friction coefficients of dielectrics is as yet poorly defined and understood. In this work, friction coefficients were measured on tribocharged polytetrafluoroethylene (PTFE), using three different techniques. As a result, friction coefficients at the macro- and nanoscales increase many-fold when PTFE surfaces are tribocharged, but this effect is eliminated by silanization of glass spheres rolling on PTFE. In conclusion, tribocharging may supersede all other contributions to macro- and nanoscale friction coefficients in PTFE and probably in other insulating polymers.

  17. Friction tensor concept for textured surfaces

    Indian Academy of Sciences (India)

    K R Y Simha; Anirudhan Pottirayil; Pradeep L Menezes; Satish V Kailas

    2008-06-01

    Directionality of grinding marks influences the coefficient of friction during sliding. Depending on the sliding direction the coefficient of friction varies between maximum and minimum for textured surfaces. For random surfaces without any texture the friction coefficient becomes independent of the sliding direction. This paper proposes the concept of a friction tensor analogous to the heat conduction tensor in anisotropic media. This implies that there exists two principal friction coefficients $\\mu_{1,2}$ analogous to the principal conductivities $k_{1,2}$. For symmetrically textured surfaces the principal directions are orthogonal with atleast one plane of symmetry. However, in the case of polished single crystalline solids in relative sliding motion, crystallographic texture controls the friction tensor.

  18. Electrochemical apparatus comprising modified disposable rectangular cuvette

    Science.gov (United States)

    Dattelbaum, Andrew M; Gupta, Gautam; Morris, David E

    2013-09-10

    Electrochemical apparatus includes a disposable rectangular cuvette modified with at least one hole through a side and/or the bottom. Apparatus may include more than one cuvette, which in practice is a disposable rectangular glass or plastic cuvette modified by drilling the hole(s) through. The apparatus include two plates and some means of fastening one plate to the other. The apparatus may be interfaced with a fiber optic or microscope objective, and a spectrometer for spectroscopic studies. The apparatus are suitable for a variety of electrochemical experiments, including surface electrochemistry, bulk electrolysis, and flow cell experiments.

  19. Rubber friction on (apparently) smooth lubricated surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Mofidi, M; Prakash, B [Division of Machine Elements, Luleaa University of Technology, Luleaa SE-97187 (Sweden); Persson, B N J [IFF, FZ-Juelich, 52425 Juelich (Germany); Albohr, O [Pirelli Deutschland AG, 64733 Hoechst/Odenwald, Postfach 1120 (Germany)

    2008-02-27

    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 make the dominant contribution to rubber friction. That is, the observed sliding friction is mainly due to the viscoelastic deformations of the rubber by the counterface surface asperities. The results presented are of great importance for rubber sealing and other rubber applications involving (apparently) smooth surfaces.

  20. Low friction wear resistant graphene films

    Science.gov (United States)

    Sumant, Anirudha V.; Berman, Diana; Erdemir, Ali

    2017-02-07

    A low friction wear surface with a coefficient of friction in the superlubric regime including graphene and nanoparticles on the wear surface is provided, and methods of producing the low friction wear surface are also provided. A long lifetime wear resistant surface including graphene exposed to hydrogen is provided, including methods of increasing the lifetime of graphene containing wear surfaces by providing hydrogen to the wear surface.

  1. Rubber friction on (apparently) smooth lubricated surfaces

    Science.gov (United States)

    Mofidi, M.; Prakash, B.; Persson, B. N. J.; Albohr, O.

    2008-02-01

    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 make the dominant contribution to rubber friction. That is, the observed sliding friction is mainly due to the viscoelastic deformations of the rubber by the counterface surface asperities. The results presented are of great importance for rubber sealing and other rubber applications involving (apparently) smooth surfaces.

  2. Modelling cohesive, frictional and viscoplastic materials

    Science.gov (United States)

    Alehossein, Habib; Qin, Zongyi

    2016-06-01

    Most materials in mining and civil engineering construction are not only viscoplastic, but also cohesive frictional. Fresh concrete, fly ash and mining slurries are all granular-frictional-visco-plastic fluids, although solid concrete is normally considered as a cohesive frictional material. Presented here is both a formulation of the pipe and disc flow rates as a function of pressure and pressure gradient and the CFD application to fresh concrete flow in L-Box tests.

  3. The role of friction in orthodontics

    OpenAIRE

    Mariana Ribeiro Pacheco; Wellington Corrêa Jansen; Dauro Douglas de Oliveira

    2012-01-01

    INTRODUCTION: Sliding mechanics is widely used during orthodontic treatment. One of the disadvantages of this mechanics is the friction generated at the bracket/archwire interface, which may reduce the amount of desired orthodontic movement obtained. Due to the application and great acceptance of this type of mechanics, the role of friction in Orthodontics has been of interest for both clinicians and scientists. OBJECTIVE: Therefore, this article discussed how friction affects orthodontic too...

  4. In-situ sputtering apparatus

    Science.gov (United States)

    Erickson, Mark R.; Poole, Henry J.; Custer, III, Arthur W.; Hershcovitch, Ady

    2015-06-09

    A sputtering apparatus that includes at least a target presented as an inner surface of a confinement structure, the inner surface of the confinement structure is preferably an internal wall of a circular tube. A cathode is disposed adjacent the internal wall of the circular tube. The cathode preferably provides a hollow core, within which a magnetron is disposed. Preferably, an actuator is attached to the magnetron, wherein a position of the magnetron within the hollow core is altered upon activation of the actuator. Additionally, a carriage supporting the cathode and communicating with the target is preferably provided, and a cable bundle interacting with the cathode and linked to a cable bundle take up mechanism provided power and coolant to the cathode, magnetron, actuator and an anode of the sputtering apparatus.

  5. APPARATUS FOR CONDENSATION AND SUBLIMATION

    Science.gov (United States)

    Schmidt, R.J.; Fuis, F. Jr.

    1958-10-01

    An apparatus is presented for the sublimation and condensation of uranium compounds in order to obtain an improved crystalline structure of this material. The apparatus comprises a vaporizing chamber and condensing structure connected thereto. There condenser is fitted with a removable liner having a demountable baffle attached to the liner by means of brackets and a removable pin. The baffle is of spiral cross-section and is provided with cooling coils disposed between the surfaces of the baffle for circulation of a temperature controlling liquid within the baffle. The cooling coll provides for controlllng the temperature of the baffle to insure formatlon of a satisfactory condensate, and the removable liner facilitates the removal of condensate formed during tbe sublimation process.

  6. X-Ray Diffraction Apparatus

    Science.gov (United States)

    Blake, David F. (Inventor); Bryson, Charles (Inventor); Freund, Friedmann (Inventor)

    1996-01-01

    An x-ray diffraction apparatus for use in analyzing the x-ray diffraction pattern of a sample is introduced. The apparatus includes a beam source for generating a collimated x-ray beam having one or more discrete x-ray energies, a holder for holding the sample to be analyzed in the path of the beam, and a charge-coupled device having an array of pixels for detecting, in one or more selected photon energy ranges, x-ray diffraction photons produced by irradiating such a sample with said beam. The CCD is coupled to an output unit which receives input information relating to the energies of photons striking each pixel in the CCD, and constructs the diffraction pattern of photons within a selected energy range striking the CCD.

  7. Synthesis gas method and apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, Sean M.; Kromer, Brian R.; Litwin, Michael M.; Rosen, Lee J.; Christie, Gervase Maxwell; Wilson, Jamie; Kosowski, Lawrence W; Robinson, Charles

    2015-11-06

    A method and apparatus for producing a synthesis gas product having one or more oxygen transport membrane elements thermally coupled to one or more catalytic reactors such that heat generated from the oxygen transport membrane element supplies endothermic heating requirements for steam methane reforming reactions occurring within the catalytic reactor through radiation and convention heat transfer. A hydrogen containing stream containing no more than 20 percent methane is combusted within the oxygen transport membrane element to produce the heat and a heated combustion product stream. The heated combustion product stream is combined with a reactant stream to form a combined stream that is subjected to the reforming within the catalytic reactor. The apparatus may include modules in which tubular membrane elements surround a central reactor tube.

  8. Microwave sterilization method and apparatus

    OpenAIRE

    V. N. Vasilenko; Minuhin, V. V.; Podorozhnyak, A. A.; Trubaev, S. I.

    1995-01-01

    Experience of industrially developed countries in utilization of microwave radiation has been analyzed. Apparatus for realization of microwave method of sterilization has been designed. A number of experiments for the estimation of bactericidal, sporacidal, and virusidal properties of microwave radiation action has been carried out in 3 to 13 cm wavelength band. B. Lycheniform shtumm G., B. Subtilis ATTC 6633, E. Coli ATTC 25922 and bacterial virus FX 174 were used as test microbes. Effect of...

  9. Thermoplastic welding apparatus and method

    Energy Technology Data Exchange (ETDEWEB)

    Matsen, Marc R.; Negley, Mark A.; Geren, William Preston; Miller, Robert James

    2017-03-07

    A thermoplastic welding apparatus includes a thermoplastic welding tool, at least one tooling surface in the thermoplastic welding tool, a magnetic induction coil in the thermoplastic welding tool and generally encircling the at least one tooling surface and at least one smart susceptor in the thermoplastic welding tool at the at least one tooling surface. The magnetic induction coil is adapted to generate a magnetic flux field oriented generally parallel to a plane of the at least one smart susceptor.

  10. Electromechanical Apparatus Measures Residual Stress

    Science.gov (United States)

    Chern, Engmin J.; Flom, Yury

    1993-01-01

    Nondestructive test exploits relationship between stress and eddy-current-probe resistance. Yields data on residual stress or strain in metal tension/compression specimen (stress or strain remaining in specimen when no stress applied from without). Apparatus is assembly of commercial equipment: tension-or-compression testing machine, eddy-current probe, impedance gain-and-phase analyzer measuring impedance of probe coil, and desktop computer, which controls other equipment and processes data received from impedance gain-and-phase analyzer.

  11. Rotor balancing apparatus and system

    Science.gov (United States)

    Lyman, Frank (Inventor); Lyman, Joseph (Inventor)

    1976-01-01

    Rotor balancing apparatus and a system comprising balance probes for measuring unbalance at the ends of a magnetically suspended rotor are disclosed. Each balance probe comprises a photocell which is located in relationship to the magnetically suspended rotor such that unbalance of the rotor changes the amount of light recorded by each photocell. The signal from each photocell is electrically amplified and displayed by a suitable device, such as an oscilloscope.

  12. How to teach friction: Experiments and models

    Science.gov (United States)

    Besson, Ugo; Borghi, Lidia; De Ambrosis, Anna; Mascheretti, Paolo

    2007-12-01

    Students generally have difficulty understanding friction and its associated phenomena. High school and introductory college-level physics courses usually do not give the topic the attention it deserves. We have designed a sequence for teaching about friction between solids based on a didactic reconstruction of the relevant physics, as well as research findings about student conceptions. The sequence begins with demonstrations that illustrate different types of friction. Experiments are subsequently performed to motivate students to obtain quantitative relations in the form of phenomenological laws. To help students understand the mechanisms producing friction, models illustrating the processes taking place on the surface of bodies in contact are proposed.

  13. Noise and vibration in friction systems

    CERN Document Server

    Sergienko, Vladimir P

    2015-01-01

    The book analyzes the basic problems of oscillation processes and theoretical aspects of noise and vibration in friction systems. It presents generalized information available in literature data and results of the authors in vibroacoustics of friction joints, including car brakes and transmissions. The authors consider the main approaches to abatement of noise and vibration in non-stationary friction processes. Special attention is paid to materials science aspects, in particular to advanced composite materials used to improve the vibroacoustic characteristics of tribopairs The book is intended for researchers and technicians, students and post-graduates specializing in mechanical engineering, maintenance of machines and transport means, production certification, problems of friction and vibroacoustics.

  14. Frictional Effects on Gear Tooth Contact Analysis

    Directory of Open Access Journals (Sweden)

    Zheng Li

    2013-01-01

    Full Text Available The present paper concentrates on the investigations regarding the situations of frictional shear stress of gear teeth and the relevant frictional effects on bending stresses and transmission error in gear meshing. Sliding friction is one of the major reasons causing gear failure and vibration; the adequate consideration of frictional effects is essential for understanding gear contact behavior accurately. An analysis of tooth frictional effect on gear performance in spur gear is presented using finite element method. Nonlinear finite element model for gear tooth contact with rolling/sliding is then developed. The contact zones for multiple tooth pairs are identified and the associated integration situation is derived. The illustrated bending stress and transmission error results with static and dynamic boundary conditions indicate the significant effects due to the sliding friction between the surfaces of contacted gear teeth, and the friction effect can not be ignored. To understand the particular static and dynamic frictional effects on gear tooth contact analysis, some significant phenomena of gained results will also be discussed. The potentially significant contribution of tooth frictional shear stress is presented, particularly in the case of gear tooth contact analysis with both static and dynamic boundary conditions.

  15. Friction Stir Processing of Cast Superalloys Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR effort examines the feasibility of an innovative fabrication technology incorporating sand casting and friction stir processing (FSP) for producing...

  16. Frictional Constitutive Parameters for Serpentine Mud from South Chamorro Seamount

    Science.gov (United States)

    Noda, H.; Shimamoto, T.; Ishii, T.

    2005-12-01

    The lack of great earthquakes in Izu-Ogasawara and Mariana subduction zones may be associated with low-temperature serpentinite (M. Kasahara, 2003). We have thus started experimental studies on fault constitutive properties of serpentinite gouge, using a biaxial frictional testing machine at Kyoto University. Many conically-shaped serpentine seamounts are developed behind those subduction zones. They are consisted mainly of serpentinite mud with clasts of mantle rocks and high-pressure metamorphic rocks. Previous studies imply that the serpentinite is likely to have formed at depths around 30km. We have used serpentine mud, consisted mainly of chrysotile, in the drill core from South Chamorro Seamount (ODP Leg195). Double shear frictional experiments have been conducted on about 0.3 mm thick gouge at 30 MPa normal stress, at room temperature and under wet conditions (but without pore pressure). A series of velocity-step tests were performed in velocity range from 0.015 to 150 μm/s. Rate-and-state constitutive laws were fit to experimental data, by solving specimen-apparatus interaction numerically searching for the optimum constitutive parameters. Determination of stiffness of the apparatus is essential for accurate estimate of constitutive parameters. Careful measurements have revealed that the total stiffness (9.00×107 N/m) fluctuates by up to about 10 % probably owing to loose alignment of machine elements. This induces errors in constitutive parameters depending on dc}. If dc is in the order of 10 μm or larger, the error in b value is in the order of percent or less. But if the dc is around 1 μm, it becomes tens of percents or larger. The absolute value of frictional coefficient is around 0.2, very low and consistent with that of pure chrysotile (Moore et al., 1997). a- σb value is about 0.005 for velocity steps at 0.015-0.15 μm/s, decreases with increasing slip rate down to about -0.01 for the velocity steps at 15-150 μm/s. It changes from positive to

  17. Job Heterogeneity and Coordination Frictions

    DEFF Research Database (Denmark)

    Kennes, John; le Maire, Daniel

    the job ladder, how the identification of assortative matching is fundamentally different in directed and undirected search models, how our theory accounts for business cycle facts related to inter-temporal changes in job offer distributions, and how our model could also be used to identify......We develop a new directed search model of a frictional labor market with a continuum of heterogenous workers and firms. We estimate two versions of the model - auction and price posting - using Danish data on wages and productivities. Assuming heterogenous workers with no comparative advantage, we...

  18. Friction of Plastic Rotating Bands

    Science.gov (United States)

    1984-11-01

    for speeds eve ., the rdnge: 10 - 300 cm/s. Overwhelming evidence was presented to support a melt phenomena. Melt depth of: polymer, pins on a glass disk...Polymers," Proc. Roy. Soc., (London),. A291 (1966), p. 186. 24. Rabinowicz , S., et al., "The Effect of Hydrostatic Pressure on the Shear Yield Behavior of...34 Proc. Roy.,Soc., (London), A269. (19620 p. 368. 51. Carignan, F. J., and Rabinowicz , E., "Friction and Wear at ligh Sliding Speeds," ASLE Trans., 24

  19. Fractional trajectories: Decorrelation versus friction

    Science.gov (United States)

    Svenkeson, A.; Beig, M. T.; Turalska, M.; West, B. J.; Grigolini, P.

    2013-11-01

    The fundamental connection between fractional calculus and subordination processes is explored and affords a physical interpretation of a fractional trajectory, that being an average over an ensemble of stochastic trajectories. Heretofore what has been interpreted as intrinsic friction, a form of non-Markovian dissipation that automatically arises from adopting the fractional calculus, is shown to be a manifestation of decorrelations between trajectories. We apply the general theory developed herein to the Lotka-Volterra ecological model, providing new insight into the final equilibrium state. The relaxation time to achieve this state is also considered.

  20. Frictional behavior of experimental faults during a simulated seismic cycle

    Science.gov (United States)

    Spagnuolo, Elena; Nielsen, Stefan; Violay, Marie; Di Felice, Fabio; Di Toro, Giulio

    2016-04-01

    Laboratory friction studies of earthquake mechanics aim at understanding complex phenomena either driving or characterizing the seismic cycle. Previous experiments were mainly conducted on bi-axial machines imposing velocity steps conditions, where slip and slip-rate are usually less than 10 mm and 1 mm/s, respectively. However, earthquake nucleation on natural faults results from the combination of the frictional response of fault materials and wall rock stiffness with complex loading conditions. We propose an alternative experimental approach which consists in imposing a step-wise increase in the shear stress on an experimental fault under constant normal stress. This experimental configuration allows us to investigate the relevance of spontaneous fault surface reworking in (1) driving frictional instabilities, (2) promoting the diversity of slip events including the eventual runaway, and (3) ruling weakening and re-strengthening processes during the seismic cycle. Using a rotary shear apparatus (SHIVA, INGV, Rome) with an on-purpose designed control system, the shear stress acting on a simulated fault can be increased step-wise while both slip and slip-rate are allowed to evolve spontaneously (the slip is namely infinite) to accommodate the new state of stress. This unconventional procedure, which we term "shear stress-step loading", simulates how faults react to either a remote tectonic loading or a sudden seismic or strain event taking place in the vicinity of a fault patch. Our experiments show that the spontaneous slip evolution results in velocity pulses whose shape and occurrence rate are controlled by the lithology and the state of stress. With increasing shear stress and cumulative slip, the experimental fault exhibits three frictional behaviors: (1) stable behavior or individual slip pulses up to few cm/s for few mm of slip in concomitance to the step-wise increase in shear stress; (2) unstable oscillatory slip or continuous slip but with abrupt changes

  1. The Architecture and Frictional Properties of Faults in Shale

    Science.gov (United States)

    De Paola, N.; Imber, J.; Murray, R.; Holdsworth, R.

    2015-12-01

    The geometry of brittle fault zones in shale rocks, as well as their frictional properties at reservoir conditions, are still poorly understood. Nevertheless, these factors may control the very low recovery factors (25% for gas and 5% for oil) obtained during fracking operations. Extensional brittle fault zones (maximum displacement oil mature black shales in the Cleveland Basin (UK). Fault cores up to 50 cm wide accommodated most of the displacement, and are defined by a stair-step geometry. Their internal architecture is characterised by four distinct fault rock domains: foliated gouges; breccias; hydraulic breccias; and a slip zone up to 20 mm thick, composed of a fine-grained black gouge. Hydraulic breccias are located within dilational jogs with aperture of up to 20 cm. Brittle fracturing and cataclastic flow are the dominant deformation mechanisms in the fault core of shale faults. Velocity-step and slide-hold-slide experiments at sub-seismic slip rates (microns/s) were performed in a rotary shear apparatus under dry, water and brine-saturated conditions, for displacements of up to 46 cm. Both the protolith shale and the slip zone black gouge display shear localization, velocity strengthening behaviour and negative healing rates, suggesting that slow, stable sliding faulting should occur within the protolith rocks and slip zone gouges. Experiments at seismic speed (1.3 m/s), performed on the same materials under dry conditions, show that after initial friction values of 0.5-0.55, friction decreases to steady-state values of 0.1-0.15 within the first 10 mm of slip. Contrastingly, water/brine saturated gouge mixtures, exhibit almost instantaneous attainment of very low steady-state sliding friction (0.1), suggesting that seismic ruptures may efficiently propagate in the slip zone of fluid-saturated shale faults. Stable sliding in faults in shale can cause slow fault/fracture propagation, affecting the rate at which new fracture areas are created and, hence

  2. Comparison of Frictional Heating Models

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-01

    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.

  3. HIV prevalence and high-risk sexual behaviours among MSM repeat and first-time testers in China: implications for HIV prevention

    Directory of Open Access Journals (Sweden)

    Xue Bai

    2014-07-01

    Full Text Available Introduction: Little is known about HIV testing, HIV infection and sexual behaviour among bathhouse patrons in China. This study aims to assess differences in HIV prevalence and high-risk sexual behaviours between repeat and first-time testers among men who have sex with men (MSM attending bathhouse in Tianjin, China. Methods: Between March 2011 and September 2012, a HIV voluntary counselling and testing station was established in a gay bathhouse, which provided HIV testing and conducted a survey among participants recruited through snowball sampling. Differences in demographic and high-risk sexual behaviours between repeat and first-time testers were assessed using the chi-square test. Univariate and multivariate logistic regression analyses were conducted to identify predictors for HIV infection. Results: Of the 1642 respondents, 699 (42.6% were repeat testers and 943 (57.4% were first-time testers. Among repeat testers, a higher proportion were men aged 18 to 25, single, better educated, had a history of STIs and worked as male sex workers or “money boys” (MBs. Repeat testers were less likely to report having unprotected anal intercourse in the past six months. The overall HIV prevalence was 12.4% (203/1642. There was no difference in HIV prevalence between repeat (11.2%, 78/699 and first-time (13.3%, 125/943 testers. The HIV prevalence increased with age among first-time testers (χ 2 trend=9.816, p=0.002. First-time MB testers had the highest HIV prevalence of 34.5%. Conclusions: MSM attending bathhouse had an alarmingly high HIV infection rate, particularly in MB. Targeted interventions are urgently needed especially focusing on older MSM and MBs.

  4. A Systematic Study on Composition of Low Viscosity Automotive Lube Oils with an Emphasis on Wear and Frictional Characteristics

    Directory of Open Access Journals (Sweden)

    Nishan Singh,

    2014-07-01

    Full Text Available In this work the performance of three commercial lube oils and two base oils of different viscosities, composition have been studied for their tribo performance using four ball tribo tester as per ASTM D 4172D and IP 239 and at the end of the test run the steel ball surfaces have been examined under scanning electron microscope (SEM to assess the wear deformities. The tribo-performance results have been co-related with the physico-chemical properties along with quantity and type of the molecules present in these oils by proton nuclear magnetic resonance (NMR studies. It has been observed that the lubricant with higher viscosity, higher aromatic molecules containing CH₂ chains shows lower friction and wear behavior whereas the increasing napthenic type molecules have reverse effect which is evident from the results.

  5. Rolling Friction on a Wheeled Laboratory Cart

    Science.gov (United States)

    Mungan, Carl E.

    2012-01-01

    A simple model is developed that predicts the coefficient of rolling friction for an undriven laboratory cart on a track that is approximately independent of the mass loaded onto the cart and of the angle of inclination of the track. The model includes both deformation of the wheels/track and frictional torque at the axles/bearings. The concept of…

  6. On the Blasius correlation for friction factors

    CERN Document Server

    Trinh, Khanh Tuoc

    2010-01-01

    The Blasius empirical correlation for turbulent pipe friction factors is derived from first principles and extended to non-Newtonian power law fluids. Two alternative formulations are obtained that both correlate well with the experimental measurements of Dodge, Bogue and Yoo. Key words: Blasius, turbulent friction factor, power law fluids

  7. FACTORS INFLUENCING FRICTION OF PHOSPHATE COATINGS,

    Science.gov (United States)

    surface roughness, crystalline structure , and velocity. The coefficients of friction for manganese phosphate coatings did not differ to any practical...The coefficient of friction was independent of the applied load. Velocity during dynamic testing, surface finish, and crystalline structure influenced

  8. The Gulf Stream: Inertia and friction

    OpenAIRE

    ASSAF, GAD

    2011-01-01

    The inertial theory of the Gulf Stream (Charney, 1955) is extended to include vertical friction in the cyclonic shear zone (the western side) of the stream. The vertical friction is assumed to be controlled by local Froude conditions.DOI: 10.1111/j.2153-3490.1977.tb00717.x

  9. Graphite friction coefficient for various conditions

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The friction coefficient the graphite used in the Tsinghua University 10MW High Tem-perature Gas-Cooled Reactor was analyzed for various conditions. The variation of the graphitefriction coefficient was measured for various sliding velocities, sliding distances, normal loads, en-vironments and temperatures. A scanning elector microscope (SEM) was used to analyze the fric-tion surfaces.

  10. Wiping Metal Transfer in Friction Stir Welding

    Science.gov (United States)

    Nunes, Arthur C., Jr.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Much evidence suggests that as the friction stir pin-tool moves along a weld seam the displacement of metal takes place by a wiping action at the surface of a plug of metal that rotates with the tool. The wiping model is explained and some consequences for the friction stir welding process are drawn.

  11. Friction-reducing and antiwear behavior of metal halide-stabilized linear phosphazene derivatives as lubricants for a steel-on-steel contact

    Institute of Scientific and Technical Information of China (English)

    ZHU; Jiamei; LIU; Weimin; LIANG; Yongmin

    2005-01-01

    A series of novel metal halide-stabilized linear phosphazene derivatives were synthesized. The friction-reducing and antiwear abilities of the resulting products as the lubricants for a steel-on-steel contact were comparatively investigated on an Optimol SRV oscillating friction and wear tester. The morphology of the worn steel surface was observed on a scanning electron microscope, while the chemical states of some typical elements on the worn steel surface were examined by means of X-ray photoelectron spectroscopy. It was found that both the side branch structures and central metals influenced the friction-reducing and antiwear behaviors of the synthetic derivatives as the lubricants, which was related to the different adsorption activities of the organic compounds composed of different organic ingredients and metallic ions on a nascent metal surface. All the synthetic lubricants except for the iron (III) derivative showed increased antiwear abilities with increasing metallic ionic radius. A protective layer originated from the tribochemical reaction together with the adsorbed boundary lubricating layer containing organic fluorine compounds, nitrogen oxide, and Fe3(PO4)2 plays an important role in improving the friction and wear behavior of the steel-on-steel system.

  12. Velocity dependence of friction of confined polymers

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Samoilov, V.N.; Persson, B.N.J.

    2009-01-01

    We present molecular dynamics friction calculations for confined hydrocarbon solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: (a) polymer sliding against a hard substrate, and (b) polymer sliding on polymer. We discuss the velocity dependence of the frictional...... cases the frictional shear stress increases monotonically with the sliding velocity. For polymer sliding on polymer [case (b)] the friction is much larger, and the velocity dependence is more complex. For hydrocarbons with molecular lengths from 60 to 140 C-atoms, the number of monolayers of lubricant...... shows no dependence on the sliding velocity, and for the shortest hydrocarbon (20 C-atoms) the frictional shear stress increases nearly linearly with the sliding velocity....

  13. Apparatuses And Systems For Embedded Thermoelectric Generators

    KAUST Repository

    Hussain, Muhammad M.

    2013-08-08

    An apparatus and a system for embedded thermoelectric generators are disclosed. In one embodiment, the apparatus is embedded in an interface where the ambient temperatures on two sides of the interface are different. In one embodiment, the apparatus is fabricated with the interface in integrity as a unitary piece. In one embodiment, the apparatus includes a first thermoelectric material embedded through the interface. The apparatus further includes a second thermoelectric material embedded through the interface. The first thermoelectric material is electrically coupled to the second thermoelectric material. In one embodiment, the apparatus further includes an output structure coupled to the first thermoelectric material and the second thermoelectric material and configured to output a voltage.

  14. Cluster Implantation and Deposition Apparatus

    DEFF Research Database (Denmark)

    Hanif, Muhammad; Popok, Vladimir

    2015-01-01

    In the current report, a design and capabilities of a cluster implantation and deposition apparatus (CIDA) involving two different cluster sources are described. The clusters produced from gas precursors (Ar, N etc.) by PuCluS-2 can be used to study cluster ion implantation in order to develop...... contributions to the theory of cluster stopping in matter as well as for practical applications requiring ultra-shallow implantation and modification of surfaces on the nanoscale. Metal clusters from the magnetron cluster source are of interest for the production of optical sensors to detect specific biological...

  15. FRICTION-BOON OR BANE IN ORTHODONTICS

    Directory of Open Access Journals (Sweden)

    Sameer

    2015-11-01

    Full Text Available OBJECTIVE: Most fixed appliance techniques involve some degree of sliding between brackets and arch wires. A sound knowledge of the various factors affecting the magnitude of friction is of paramount importance to the clinician. The present study was performed to evaluate and compare the frictional resistance and characteristics between self-ligating brackets and pre-adjusted edgewise brackets with different types of ligation. MATERIALS AND METHODS: Tidy's frictional test design was used to simulate retraction of tooth along with artificial saliva to simulate wet conditions in oral cavity. The jig with this assembly was mounted on the Instron machine with the cross head moving upwards at a speed of 5mm/min. The movable bracket was suspended from the load cell of the testing machine, while the jig was mounted on cross head of machine and the load cell readings were recorded on digital display. Following wires are used 0.016 HANT, 0.019X 0.025HANT, 0.019X 0.025 SS, 0.021X 0.025 SS wires are used. The brackets used were 0.022 slot Damon, 0.022 Smart clip and 0.022 slot MBT system. RESULTS: Self ligating brackets were shown to produce lesser friction when compared to the conventional brackets used with modules, and stainless steel ligatures. Damon self-ligating brackets produce a least friction of all the brackets used in the study. Stainless steel ligatures produced the least friction compared to elastomeric. CONCLUSION: Self ligation brackets produce lesser friction than the conventional brackets ligated with elastomeric modules and stainless steel ligature. Damon self-ligating brackets produce a least friction of all the brackets used in the study width of the bracket was also found to be directly proportional to the friction produced 0.0016HANT with elastomeric modules produce more friction due increase in flexibility of wire.

  16. Spectroscopic signatures of quantum friction

    Science.gov (United States)

    Klatt, Juliane; Bennett, Robert; Buhmann, Stefan Yoshi

    2016-12-01

    We present a formula for the spectroscopically accessible level shifts and decay rates of an atom moving at an arbitrary angle relative to a surface. Our Markov formulation leads to an intuitive analytic description whereby the shifts and rates are obtained from the coefficients of the Heisenberg equation of motion for the atomic flip operators but with complex Doppler-shifted (velocity-dependent) transition frequencies. Our results conclusively demonstrate that for the limiting case of parallel motion the shifts and rates are quadratic or higher in the atomic velocity. We show that a stronger, linear velocity dependence is exhibited by the rates and shifts for perpendicular motion, thus opening the prospect of experimentally probing the Markovian approach to the phenomenon of quantum friction.

  17. Friction Stir Welding and Processing

    Energy Technology Data Exchange (ETDEWEB)

    Hovanski, Yuri; Carsley, John; Clarke, Kester D.; Krajewski, Paul E.

    2015-05-01

    With nearly twenty years of international research and collaboration in friction stir welding (FSW) and processing industrial applications have spread into nearly every feasible market. Currently applications exist in aerospace, railway, automotive, personal computers, technology, marine, cutlery, construction, as well as several other markets. Implementation of FSW has demonstrated diverse opportunities ranging from enabling new materials to reducing the production costs of current welding technologies by enabling condensed packaging solutions for traditional fabrication and assembly. TMS has sponsored focused instruction and communication in this technology area for more than fifteen years, with leadership from the Shaping and Forming Committee, which organizes a biannual symposium each odd year at the annual meeting. A focused publication produced from each of these symposia now comprises eight volumes detailing the primary research and development activities in this area over the last two decades. The articles assembled herein focus on both recent developments and technology reviews of several key markets from international experts in this area.

  18. Mapping Instabilities in Polymer Friction

    Science.gov (United States)

    Rand, Charles; Crosby, Alfred

    2005-03-01

    Schallamach waves are instabilities that occur as interfaces between a soft elastomer and rigid surface slide past each other.(1) The presence of Schallamach waves can lead to drastic changes in frictional properties. Although the occurrence of Schallamach waves has been studied for the past several decades, a general map relating fundamental material properties, geometry, and operating conditions (i.e. speed and temperature) has not been established. Using a combinatorial approach, we illustrate the role of modulus, testing velocity and surface energetics of crosslinked poly(dimethyl siloxane) on the generation Schallamach waves. This knowledge will be used with polymer patterning processes to fabricate responsive coatings for applications such as anti-fouling coatings. (1)Schallamach, A.;Wear 1971,17, 301-312.

  19. Dynamical Friction on extended perturbers

    CERN Document Server

    Esquivel, O

    2008-01-01

    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.

  20. Lateral Ignition and Flame Spread Apparatus

    Data.gov (United States)

    Federal Laboratory Consortium — Description: This apparatus, developed at EL, determines material properties related to piloted ignition of a vertically oriented sample under constant and uniform...

  1. Design of Real-Time Gas Emission Tester for Diesel Power Plant Applications

    Directory of Open Access Journals (Sweden)

    An sar Suyuti

    2013-01-01

    Full Text Available The paper proposes design of real-time gas emission tester for diesel power plant applications. Several sensors are utilized in our design system, such as sensor of KE for O2 gas, MQ136 for SO2 gas, TGS 2201 for NOx gas, MQ7 for CO gas, MQ2 for smoke opacity including Modul DT-Sense SHT 11 sensor for temperature and humidity. All sensors basically produce analog output voltage; therefore the analog data is converted to 8 bit digital data for the further processing and controlling in the ADC pin of ATmega16 microcontroller. The real-time measurement results can be monitored through visualization in Liquid Crystal Display (LCD and computer monitor after data processing using microcontroller ATmega16 under programming environment of CodeVision AVR V2.03.4. The visualization itself is designed based on the combination between programming language of Microsoft Visual Basic ver. 6.0 and Borland C++. The experimental results show that the proposed design is working properly. The information related to the emitted gas from plant chimney can be collected, stored in real-time and accessed online through web based interface systems

  2. Appropriate electrode placement site of electric pulp tester for the premolars: A clinical study

    Directory of Open Access Journals (Sweden)

    Seema Dinesh Bargale

    2015-01-01

    Full Text Available Context: Electric pulp testers (EPTs are widely used as diagnostic aid in dentistry for dental pulp. This delivers enough current to overcome enamel and dentin resistance and to stimulate the myelinated sensory fibers at the junction of pulp and dentin. Such testing requires the electrode to be in contact with the surface of the tooth, with optimal positions identified for anterior teeth, premolars, and molars. Aims: To determine the best site position of EPT on premolars. The objective of electric pulp testing was to determine the sensibility of each premolar at the lowest sensory response threshold. Settings and Design: Clinical study Materials and Methods: The premolars of 20 patients between 13 and 15 years accompanied with parents, free of restorations, and caries were selected. Five sites on the crown were tested with EPT for minimum of four times. Statistical analysis used: One-way analysis of variance test and the Tukey′s honestly significant difference test. Results: The lowest threshold response was noted at the incisal edge of the tooth; the middle third had a higher threshold among all the different placement of electrode. Statistically significant difference was observed for occlusal surface in terms of region of placement of electrode. Conclusions: This experiment found the best electrode site for pulp testing in premolars. The appropriate EPT site was on the occlusal surface of maxillary and mandibular premolars.

  3. Inter-tester reliability of a new diagnostic classification system for patients with non-specific low back pain

    DEFF Research Database (Denmark)

    Petersen, Tom Erik; Olsen, Steen; Laslett, Mark

    2004-01-01

    Most patients referred to physiotherapy with low back pain are without a precise medical diagnosis. Identification of subgroups of non-specific low back pain patients may improve clinical outcomes and research efficiency. A pathoanatomic classification system has been developed, classifying......% and the kappa coefficient was 0.62 for the mutually exclusive syndromes in the classification system. Agreement rates for each of the syndromes ranged from 74% to 100% and kappa coefficients ranged from 0.44 to 1.00. The findings suggest the inter-tester reliability of the system is acceptable. The relatively...... patients with non-specific low back pain into 12 different syndromes and three subcategories based on history and physical examination. The purpose of this study was to estimate the inter-tester reliability of clinical tests used as criteria for classifying patients. Ninety patients with chronic low back...

  4. Dynamic rupture simulation with an experimentally-determined friction law leads to slip-pulse propagation

    Science.gov (United States)

    Liao, Z.; Chang, J. C.; Reches, Z.

    2013-12-01

    We simulate the dynamic rupture along a vertical, strike-slip fault in an elastic half-space. The fault has frictional properties that were determined in high-velocity, rotary shear apparatus Sierra-White granite. The experimental fault was abruptly loaded by a massive flywheel, which is assumed to simulate the loading of a fault patch during an earthquake, and termed Earthquake-Like-Slip Event (ELSE) (Chang et al., 2012). The experiments revealed systematic alteration between slip-weakening and slip-strengthening (Fig. 1A), and were considered as proxies of fault-patch behavior during earthquakes of M = 4-8. We used the friction-distance relations of these experiments to form an empirical slip-dependent friction model, ELSE-model (Fig. 1B). For the dynamic rupture simulation, we used the program of Ampuero (2002) (2D spectral boundary integral elements) designed for anti-plane (mode III) shear fracturing. To compare with published works, the calculations used a crust with mechanical properties and stress state of Version 3 benchmark of SCEC (Harris et al., 2004). The calculations with a fault of ELSE-model friction revealed: (1) Rupture propagation in a slip-pulse style with slip cessation behind the pulse; (2) Systematic decrease of slip distance away from the nucleation zone; and (3) Spontaneous arrest of the dynamic rupture without a barrier. These features suggest a rupture of a self-healing slip-pulse mode (Fig. 1C), in contrast to rupturing of a fault with linear slip-weakening friction (Fig. 1B) (Rojas et al., 2008) in crack-like mode and no spontaneous arrest. We deduce that the slip-pulse in our simulation results from the fast recovery of shear strength as observed in ELSE experiments, and argue that incorporating this experimentally-based friction model to rupture modeling produces realistic propagation style of earthquake rupture. Figure 1 Fault patch behavior during an earthquake. (A) Experimental evolution of frictional stress, slip velocity, and

  5. Master-slave micromanipulator apparatus

    Science.gov (United States)

    Morimoto, Alan K.; Kozlowski, David M.; Charles, Steven T.; Spalding, James A.

    1999-01-01

    An apparatus based on precision X-Y stages that are stacked. Attached to arms projecting from each X-Y stage are a set of two axis gimbals. Attached to the gimbals is a rod, which provides motion along the axis of the rod and rotation around its axis. A dual-planar apparatus that provides six degrees of freedom of motion precise to within microns of motion. Precision linear stages along with precision linear motors, encoders, and controls provide a robotics system. The motors can be positioned in a remote location by incorporating a set of bellows on the motors and can be connected through a computer controller that will allow one to be a master and the other one to be a slave. Position information from the master can be used to control the slave. Forces of interaction of the slave with its environment can be reflected back to the motor control of the master to provide a sense of force sensed by the slave. Forces import onto the master by the operator can be fed back into the control of the slave to reduce the forces required to move it.

  6. Tube wall thickness measurement apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, P.R.

    1985-06-21

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and radius by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  7. Tube wall thickness measurement apparatus

    Science.gov (United States)

    Lagasse, P.R.

    1985-06-21

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and radius by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  8. Tube wall thickness measurement apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, Paul R. (Santa Fe, NM)

    1987-01-01

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and circumference by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  9. Apparatus for incinerating hazardous waste

    Science.gov (United States)

    Chang, R.C.W.

    1994-12-20

    An apparatus is described for incinerating wastes, including an incinerator having a combustion chamber, a fluid-tight shell enclosing the combustion chamber, an afterburner, an off-gas particulate removal system and an emergency off-gas cooling system. The region between the inner surface of the shell and the outer surface of the combustion chamber forms a cavity. Air is supplied to the cavity and heated as it passes over the outer surface of the combustion chamber. Heated air is drawn from the cavity and mixed with fuel for input into the combustion chamber. The pressure in the cavity is maintained at least approximately 2.5 cm WC higher than the pressure in the combustion chamber. Gases cannot leak from the combustion chamber since the pressure outside the chamber (inside the cavity) is higher than the pressure inside the chamber. The apparatus can be used to treat any combustible wastes, including biological wastes, toxic materials, low level radioactive wastes, and mixed hazardous and low level transuranic wastes. 1 figure.

  10. ON/OFF POWER SWITCH DAN REMOTE CONTROL BERBASIS MICROCONTROLLER ATMEGA8 SEBAGAI RELIABILITY TESTER CRT DANLCD TV

    Directory of Open Access Journals (Sweden)

    Fina Supegina

    2013-10-01

    Full Text Available Mikrokontroler sebagai suatu terobosan teknologi mikroprosesor dan mikrokomputer, hadir memenuhi kebutuhan pasar dan teknologi baru. Sebagai teknologi baru, yaitu teknologi semikonduktor dengan kandungan transistor yang lebih banyak namun hanya membutuhkan ruang yang lebih kecil serta dapat diproduksi secara masal sehingga harganya menjadi lebih murah (dibandingkan dengan mikroprosesor. Sebagai kebutuhan pasar, mikrokontroler hadir untuk memenuhi selera industri dan para konsumen akan kebutuhan dan keinginan alat-alat bantu yang lebih baik dan canggih. Quality Engineering merupakan bagian dari Departemen Quality Assurance yang melakukan proses studi dan menganalisa semua produk baru sebelum diproduksi secara masal (Mass production dan sebelum dijual ke pasaran lokal maupun ekspor, pada bagian ini dilakukan proses pembelajaran dan penganalisaan secara detail kemampuan komponen pada CRT TV dan LCD TV yang dapat mempengaruhi kinerja dari produk itu sendiri. Disamping itu juga dilakukanlah pengetesan terhadap reliability (ketahanan suatu produk baru ini salah satu dengan cara menghidupkan dan mematikan power switch dan juga melalui remote kontrolnya. Pada saat melakukan pengetesan reliability ini terasa sangat membosankan, melelahkan karena dilakukan secara manual, jadi dengan kondisi seperti ini cukup menyita waktu dan menghambat bagi seorang engineer dalam mempelajari dan menganalisa dari produk baru lebih lanjut. Solusi dari masalah yang ada dihadapi oleh engineer untuk menunjang dan mengetahui kemampuan komponen yang dipakai CRT TV dan LCD TV adalah dengan dibuatnya sebuah alat Reliability Tester Otomatic yang memanfaatkan sebuah IC Mikrokontroler ATmega8 sebagai otak pengendalinya. Dengan adanya sebuah Reliability Tester Otomatic tersebut, dapat mengetahui ketahanan dari produk televisi baik CRT TV juga LCD TV saat dihidupkan dan dimatikan secara berulang-ulang, sebelum dipergunakan oleh konsumen. Efektivitas kerja seorang engineer yang

  11. Application of SimpleTester in MIB Test%SimpleTester在MIB测试中的应用

    Institute of Scientific and Technical Information of China (English)

    曾定洲; 唐丽莉

    2013-01-01

      随着大家对网络设备易用性要求的提高,人们越来越倾向于完全使用图形化界面的网管系统来完成对设备的管理和维护。而MIB(Management Information Base)作为网管系统管理网络设备的“中间件”,其定义、设计的规范性和标准遵从性也变得越来越重要。传统的MIB测试工具效率低下,文中介绍了一种高效测试工具SimpleTester在MIB测试中的应用,详细介绍了SimpleTester的框架结构以及使用SimpleTester进行MIB测试的一般流程,并通过例子说明了SimpleTest-er能帮忙我们极大地提高测试效率和质量。%With the improved easy-using requirements of network equipment,there is more and more inclined to use graphical network management system to complete the management and maintenance of network element. MIB (Management Information Base) as the "middleware" between network management system and network element,its definition,design specifications and standards compliance is also becoming increasingly important. As the inefficiency of traditional MIB testing tools,introduce an efficient testing tool SimpleTester in MIB test,in detail the framework structure of SimpleTester and general process of how to use SimpleTester in MIB test. In the end,an example is given to illustrate greatly improve the test efficiency and quality with SimpleTester's help.

  12. Temperature dependent effective friction coefficient estimation in friction stir welding with the bobbin tool

    Directory of Open Access Journals (Sweden)

    Mijajlović Miroslav M.

    2016-01-01

    Full Text Available The friction coefficient in many friction stir welding researches is generally used as an effective, constant value without concern on the adaptable and changeable nature of the friction during welding sequence. This is understandable because the main problem in analyzing friction in friction stir welding are complex nature of the friction processes, case-dependent and time dependent contact between the bodies, influence of the temperature, sliding velocity, etc. This paper is presenting a complex experimental-numerical-analytical model for estimating the effective friction coefficient on contact of the bobbin tool and welding plates during welding, considering the temperature at the contact as the most influencing parameter on friction. The estimation criterion is the correspondence of the experimental temperature and temperature from the numerical model. The estimation procedure is iterative and parametric - the heat transport parameters and friction coefficient are adapted during the estimation procedure in a realistic manner to achieve relative difference between experimental and model’s temperature lower than 3%. The results show that friction coefficient varies from 0.01 to 0.21 for steel-aluminium alloy contact and temperature range from 406°C to 22°C.

  13. Scheduling Semiconductor Multihead Testers Using Metaheuristic Techniques Embedded with Lot-Specific and Configuration-Specific Information

    Directory of Open Access Journals (Sweden)

    Yi-Feng Hung

    2013-01-01

    Full Text Available In the semiconductor back-end manufacturing, the device test central processing unit (CPU is most costly and is typically the bottleneck machine at the test plant. A multihead tester contains a CPU and several test heads, each of which can be connected to a handler that processes one lot of the same device. The residence time of a lot is closely related to the product mix on test heads, which increases the complexity of this problem. It is critical for the test scheduling problem to reduce CPU's idle time and to increase tester utilization. In this paper, a multihead tester scheduling problem is formulated as an identical parallel machine scheduling problem with the objective of minimizing makespan. A heuristic grouping method is developed to obtain a good initial solution in a short time. Three metaheuristic techniques, using lot-specific and configuration-specific information, are proposed to receive a near-optimum and are compared to traditional approaches. Computational experiments show that a tabu search with lot-specific information outperforms all other competing approaches.

  14. Thermal activation in boundary lubricated friction

    Energy Technology Data Exchange (ETDEWEB)

    Michael, P.C. [Francis Bitter National Magnet Lab. and Dept. of Mechanical Engineering, Massachusetts Inst. of Tech., Cambridge, MA (United States); Rabinowicz, E. [Francis Bitter National Magnet Lab. and Dept. of Mechanical Engineering, Massachusetts Inst. of Tech., Cambridge, MA (United States); Iwasa, Y. [Francis Bitter National Magnet Lab. and Dept. of Mechanical Engineering, Massachusetts Inst. of Tech., Cambridge, MA (United States)

    1996-05-01

    The friction coefficients for copper pairs lubricated with fatty acids and fluorinated fatty acids have been measured over a wide range of sliding speeds and temperatures. Sliding speeds in the range 10{sup -7}-10{sup -2} m s{sup -1} and temperatures in the range 4.2-300 K were used. The friction coefficients near 300 K are generally low and increase with sliding speed, while the friction coefficients at low temperatures are markedly higher and relatively independent of velocity. Each lubricant`s friction vs. velocity behavior over the temperature range 150-300 K can be described by a friction-velocity master curve derived from a thermal activation model for the lubricant`s shear strength. The activation energies deduced from this friction model are identical to those obtained in the same temperature range for a vibrational mode associated with low temperature mechanical relaxations in similarly structured polymers. These results suggest that thermally activated interfacial shear is responsible for the fatty acids` positive-sloped friction vs. velocity characteristics at low sliding speeds near room temperature. (orig.)

  15. Load-Dependent Friction Hysteresis on Graphene.

    Science.gov (United States)

    Ye, Zhijiang; Egberts, Philip; Han, Gang Hee; Johnson, A T Charlie; Carpick, Robert W; Martini, Ashlie

    2016-05-24

    Nanoscale friction often exhibits hysteresis when load is increased (loading) and then decreased (unloading) and is manifested as larger friction measured during unloading compared to loading for a given load. In this work, the origins of load-dependent friction hysteresis were explored through atomic force microscopy (AFM) experiments of a silicon tip sliding on chemical vapor deposited graphene in air, and molecular dynamics simulations of a model AFM tip on graphene, mimicking both vacuum and humid air environmental conditions. It was found that only simulations with water at the tip-graphene contact reproduced the experimentally observed hysteresis. The mechanisms underlying this friction hysteresis were then investigated in the simulations by varying the graphene-water interaction strength. The size of the water-graphene interface exhibited hysteresis trends consistent with the friction, while measures of other previously proposed mechanisms, such as out-of-plane deformation of the graphene film and irreversible reorganization of the water molecules at the shearing interface, were less correlated to the friction hysteresis. The relationship between the size of the sliding interface and friction observed in the simulations was explained in terms of the varying contact angles in front of and behind the sliding tip, which were larger during loading than unloading.

  16. Assessment of semi-active friction dampers

    Science.gov (United States)

    dos Santos, Marcelo Braga; Coelho, Humberto Tronconi; Lepore Neto, Francisco Paulo; Mafhoud, Jarir

    2017-09-01

    The use of friction dampers has been widely proposed for a variety of mechanical systems for which applying viscoelastic materials, fluid based dampers or other viscous dampers is impossible. An important example is the application of friction dampers in aircraft engines to reduce the blades' vibration amplitudes. In most cases, friction dampers have been studied in a passive manner, but significant improvements can be achieved by controlling the normal force in the contact region. The aim of this paper is to present and study five control strategies for friction dampers based on three different hysteresis cycles by using the Harmonic Balance Method (HBM), a numerical and experimental analysis. The first control strategy uses the friction force as a resistance when the system is deviating from its equilibrium position. The second control strategy maximizes the energy removal in each harmonic oscillation cycle by calculating the optimal normal force based on the last displacement peak. The third control strategy combines the first strategy with the homogenous modulation of the friction force. Finally, the last two strategies attempt to predict the system's movement based on its velocity and acceleration and our knowledge of its physical properties. Numerical and experimental studies are performed with these five strategies, which define the performance metrics. The experimental testing rig is fully identified and its parameters are used for numerical simulations. The obtained results show the satisfactory performance of the friction damper and selected strategy and the suitable agreement between the numerical and experimental results.

  17. Friction and wear characteristics of Al-Cu/C composites synthesized using partial liquid phase casting process

    Energy Technology Data Exchange (ETDEWEB)

    Ng, W.B.; Gupta, M.; Lim, S.C. [Department of Mechanical and Production Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore (Singapore)

    1997-10-01

    During the sliding of aluminium alloys dispersed with graphite particulates, a layer of graphite is usually present at the sliding interface. This tribo-layer significantly reduces the amount of direct metal-to-metal contact, giving rise to low friction and a low rate of wear, making these composites useful candidate materials for anti-friction applications. Such self-lubricating composites are commonly fabricated via the squeeze casting, slurry casting or powder metallurgy route. These processes are expensive while the less-expensive conventional casting route is limited by the agglomeration of graphite particles in the composites, giving rise to poor mechanical properties. In this work, graphite particulate-reinforced Al-4.5 wt.% Cu composites with two effective graphite contents (Al-4.5 Cu/4.2 wt.% C and Al-4.5 Cu/6.8 wt.% C) were synthesized through an innovative partial liquid phase casting (rheocasting) technique, which is a modification of the conventional casting process. Unlubricated (without the use of conventional liquid lubrication) friction and wear performance of these composites as well as the un-reinforced aluminium alloy was determined using a pin-on-disk tester. The results revealed that the graphite-reinforced composites have a higher wear rate than the un-reinforced matrix alloy while their frictional characteristics are very similar within the range of testing conditions. Combining these with the information gathered from worn-surface examinations and wear-debris analysis, it is suggested that there exists a certain threshold for the amount and size of graphite particulates in these composites to enable them to have improved tribological properties. (Copyright (c) 1997 Elsevier Science B.V., Amsterdam. All rights reserved.)

  18. The role of fluid pressure in frictional stability and earthquake triggering: insights from laboratory experiments

    Science.gov (United States)

    Collettini, Cristiano; Scuderi, Marco

    2015-04-01

    Fluid overpressure has been proposed as one of the primary mechanisms that facilitate earthquake slip along faults. However, elastic dislocation theory combined with friction laws suggests that fluid overpressure may inhibit the dynamic instabilities that result in earthquakes, by controlling the critical fault stiffness (kc). This controversy poses a serious problem in our understanding of earthquake physics, with severe implications for both natural and human-induced seismic hazard. Nevertheless, currently, there are no systematic studies on the role of fluid pressure under controlled, laboratory conditions for which the evolution of friction parameters and slip stability can be measured. We have used a state-of-the-art biaxial rock deformation apparatus within a pressure vessel, in order to allow a true triaxial stress field, in a double direct shear configuration. We tested carbonate fault gouge, Carrara marble, sieved to a grain size of 125 μm. Normal stresses and confining pressure were held constant throughout the experiment at values of 5 to 40 MPa, and the pore fluid pressure was varied from hydrostatic up to near lithostatic values. Shear stress was induced by a constant displacement rate and sliding velocities varied from 0.1-1000 μm/s, in order to evaluate slip stability via rate- and state- dependent frictional parameters, such as (a-b), Dc and kc. Our data show that sliding velocity controls the values of friction parameters. In addition we observe a general increase of (a-b) and a decrease of Dc with increasing fluid pressure. Our observations suggest that fluid overpressure does not only facilitate fault reactivation but it also influences frictional parameters with important implications for fault stability and earthquake triggering.

  19. Coordinated Water Under Confinement Eases Sliding Friction

    Science.gov (United States)

    Defante, Adrian; Dhopotkar, Nishad; Dhinojwala, Ali

    Water is essential to a number of interfacial phenomena such as the lubrication of knee joints, protein folding, mass transport, and adsorption processes. We have used a biaxial friction cell to quantify underwater friction between a hydrophobic elastomeric lens and a hydrophobic self-assembled monolayer in the presence of surfactant solutions. To gain an understanding of the role of water in these processes we have coupled this measurement with surface sensitive sum frequency generation to directly probe the molecular constitution of the confined contact interface. We observe that role of confined coordinated water between two hydrophobic substrates covered with surfactants is the key to obtaining a low coefficient of friction.

  20. An inquiry-based laboratory on friction

    CERN Document Server

    Montalbano, Vera

    2013-01-01

    Sliding friction is usually introduced in high school, but rarely through activities in laboratory. A qualitative introduction to friction is presented by proposing exploration of different kind of materials in order to suggest which aspects can be relevant and which interaction is involved. Different quantitative experiments are proposed for studying Leonardo's laws for friction. The learning path was tested with two high school classes during an instruction trip at department. Students were engaged in the inquiry-based introductory activity and seemed to realize with care the measurements. However, the analysis of their reports shows some learning difficulties.

  1. Methods and Devices used to Measure Friction

    DEFF Research Database (Denmark)

    Jeswiet, Jack; Arentoft, Mogens; Henningsen, Poul

    2004-01-01

    The physical condition at the work-piece/die boundary, in both bulk forming and sheet forming is, arguably, the single most important physical parameter influencing the processing of metals, yet it remains the least understood. Hence the need for basic research into metal-die interface mechanisms....... To gain a good understanding of the mechanisms at the interface and to be able to verify the friction and tribology models that exist, friction sensors are needed. Designing sensors to measure friction-stress in metal working has been pursued by many researchers. This paper surveys methods, which have...

  2. Quantized friction across ionic liquid thin films

    Science.gov (United States)

    Smith, Alexander M.; Lovelock, Kevin R. J.; Gosvami, Nitya Nand; Welton, Tom; Perkin, Susan

    Ionic liquids, salts in the liquid state under ambient conditions, are of great interest as precision lubricants. Ionic liquids form layered structures at surfaces, yet it is not clear how this nano-structure relates to their lubrication properties. We measured the friction force between atomically smooth solid surfaces across ionic liquid films of controlled thickness in terms of the number of ion layers. Multiple friction-load regimes emerge, each corresponding to a different number of ion layers in the film. In contrast to molecular liquids, the friction coefficients differ for each layer due to their varying composition.

  3. Forming of aluminium alloy friction stir welds

    Science.gov (United States)

    Bruni, Carlo

    2016-10-01

    The present paper aims at investigating, through analytical models, numerical models and experiments, the effect of the warm deformation phase, realised with an in temperature upsetting, on the weld previously performed by friction stir lap welding on aluminium alloy blanks. The investigation allows to show the deformation zones after upsetting that determine the homogenisation of the weld section. The analytical model allows to relate the friction factor with the upsetting load. The presence on the weld of not elevated friction factor values determines the deformation and localisation levels very useful for the weld. Such methodology allows to improve the weld itself with the forming phase.

  4. Study on the Friction Coefficient in Grinding

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The friction between the abrasive grains and workpi ec e is a crutial factor determining the main grinding output. Few studies have bee n carried out investigating the values of the friction coefficient in grinding, due to the difficulty of direct measurement. In this paper, a mathematical model of the friction coefficient in grinding has been established with the aid of a new grinding parameter C ge, which has close relations to wheel wear rate Z s, metal removal rate Z w, specific energy u and gr...

  5. Quantized friction across ionic liquid thin films.

    Science.gov (United States)

    Smith, Alexander M; Lovelock, Kevin R J; Gosvami, Nitya Nand; Welton, Tom; Perkin, Susan

    2013-10-07

    Ionic liquids - salts in the liquid state under ambient conditions - are of great interest as precision lubricants. Ionic liquids form layered structures at surfaces, yet it is not clear how this nano-structure relates to their lubrication properties. We measured the friction force between atomically smooth solid surfaces across ionic liquid films of controlled thickness in terms of the number of ion layers. Multiple friction-load regimes emerge, each corresponding to a different number of ion layers in the film. In contrast to molecular liquids, the friction coefficients differ for each layer due to their varying composition.

  6. Apparatus Named After Our Academic Ancestors, III

    Science.gov (United States)

    Greenslade, Thomas B.

    2014-09-01

    My academic ancestors in physics have called on me once more to tell you about the apparatus that they devised, and that many of you have used in your demonstrations and labs. This article is about apparatus named after François Arago, Heinrich Helmholtz, Leon Foucault, and James Watt.

  7. On an Actual Apparatus for Conceptual Change.

    Science.gov (United States)

    Macbeth, Douglas

    2000-01-01

    Organizes a reading of the conceptual change literature that brings into view a collection of design specifications for a conceptual change apparatus. Analyzes one such apparatus in the particulars of a science education demonstration program produced by the Harvard-Smithsonian Private Universe Project. (Contains 114 references.) (Author/WRM)

  8. Apparatus Named after Our Academic Ancestors, III

    Science.gov (United States)

    Greenslade, Thomas B., Jr.

    2014-01-01

    My academic ancestors in physics have called on me once more to tell you about the apparatus that they devised, and that many of you have used in your demonstrations and labs. This article is about apparatus named after François Arago, Heinrich Helmholtz, Leon Foucault, and James Watt.

  9. Method of magnetic separation and apparatus therefore

    Science.gov (United States)

    Oder, Robin R. (Inventor)

    1991-01-01

    An apparatus for magnetically separating and collecting particulate matter fractions of a raw sample according to relative magnetic susceptibilities of each fraction so collected is disclosed. The separation apparatus includes a splitter which is used in conjunction with a magnetic separator for achieving the desired fractionation.

  10. High friction and low wear properties of laser-textured ceramic surface under dry friction

    Science.gov (United States)

    Xing, Youqiang; Deng, Jianxin; Wu, Ze; Wu, Fengfang

    2017-08-01

    Two kinds of grooved textures with different spacing were fabricated on Al2O3/TiC ceramic surface by an Nd:YAG laser. The dry tribological properties of the textured samples were investigated by carrying out unidirectional rotary sliding friction and wear tests using a ball-on-disk tribometer. Results show that the laser textured samples exhibit higher friction coefficient and excellent wear resistance compared with the smooth sample under dry friction conditions. Furthermore, the texture morphology and spacing have a significant influence on the tribological properties. The sample with small texture spacing may be beneficial to increasing the friction coefficient, and the wavy-grooved sample exhibits the highest friction coefficient and shallowest wear depth. The increasing friction coefficient and anti-wear properties are attributed to the combined effects of the increased surface roughness, reduced real contact area, micro-cutting effect by the texture edges and entrapment of wear debris.

  11. Modeling of column apparatus processes

    CERN Document Server

    Boyadjiev, Christo; Boyadjiev, Boyan; Popova-Krumova, Petya

    2016-01-01

    This book presents a new approach for the modeling of chemical and interphase mass transfer processes in industrial column apparatuses, using convection-diffusion and average-concentration models. The convection-diffusion type models are used for a qualitative analysis of the processes and to assess the main, small and slight physical effects, and then reject the slight effects. As a result, the process mechanism can be identified. It also introduces average concentration models for quantitative analysis, which use the average values of the velocity and concentration over the cross-sectional area of the column. The new models are used to analyze different processes (simple and complex chemical reactions, absorption, adsorption and catalytic reactions), and make it possible to model the processes of gas purification with sulfur dioxide, which form the basis of several patents.

  12. Apparatus for solar coal gasification

    Science.gov (United States)

    Gregg, D.W.

    Apparatus for using focused solar radiation to gasify coal and other carbonaceous materials is described. Incident solar radiation is focused from an array of heliostats onto a tower-mounted secondary mirror which redirects the focused solar radiation down through a window onto the surface of a vertically-moving bed of coal, or a fluidized bed of coal, contained within a gasification reactor. The reactor is designed to minimize contact between the window and solids in the reactor. Steam introduced into the gasification reactor reacts with the heated coal to produce gas consisting mainly of carbon monoxide and hydrogen, commonly called synthesis gas, which can be converted to methane, methanol, gasoline, and other useful products. One of the novel features of the invention is the generation of process steam at the rear surface of the secondary mirror.

  13. Apparatuses to support photovoltaic modules

    Energy Technology Data Exchange (ETDEWEB)

    Ciasulli, John; Jones, Jason

    2017-08-22

    Methods and apparatuses to support photovoltaic ("PV") modules are described. A saddle bracket has a mounting surface to support one or more PV modules over a tube, a gusset coupled to the mounting surface, and a mounting feature coupled to the gusset to couple to the tube. A grounding washer has a first portion to couple to a support; and a second portion coupled to the first portion to provide a ground path to a PV module. A PV system has a saddle bracket; a PV module over the saddle bracket; and a grounding washer coupled to the saddle bracket and the PV module. Saddle brackets can be coupled to a torque tube at predetermined locations. PV modules can be coupled to the saddle brackets.

  14. APPARATUS FOR LIQUID PHASE EXTRACTION

    Science.gov (United States)

    Hicks, T.R.; Lehman, H.R.; Rubin, B.

    1958-09-16

    operation is described. It comprises a tubular colunm having upper and lower enlarged terminal portions, and a constricted central section containing fluid dispersal packing. Pulsing means are coupled to the upper portion of the column. The inlet for the less dense phase is located above the inlet for the denser phase and both are positioned so that liquids enter the constricted packingfilled central section. The apparatos also includes an interfacing level control, and means fer sensing the level of the interface actuate apparatus for controlling the rate of flow of input or discharge. The outlet for the less dense phase is located in the upper packing free portion of the colunm and that of the denser phase in the lower portion.

  15. Tube wall thickness measurement apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, P.R.

    1987-01-06

    An apparatus is described for measuring the thickness of a tube's wall for the tube's entire length and circumference by determining the deviation of the tube wall thickness from the known thickness of a selected standard item, the apparatus comprising: a. a base; b. a first support member having first and second ends, the first end being connected to the base, the first support member having a sufficiently small circumference that the tube can be slid over the first support member; c. a spherical element, the spherical element being connected to the second end of the first support member. The spherical element has a sufficiently small circumference at its equator that the tube can be slid over the spherical element, the spherical element having at its equator a larger circumference than the first support member; d. a second support member having first and second ends, the first end being connected to the base, the second support member being spaced apart form the first support member; e. a positioning element connected to and moveable relative to the second support member; and f. an indicator connected to the positioning element and being moveable thereby to a location proximate the spherical element. The indicator includes a contact ball for contacting the selected standard item and holding it against the spherical element, the contact ball contacting the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item, the rotatable needle being operatively connected to and responsive to the position of the contact ball.

  16. Frictional torque numbers for ball cup and journal bearings

    OpenAIRE

    Ligterink, D.J.

    1982-01-01

    Plastic bearing material wears in ball cup and journal bearings. Contact areas in the ball cup and the journal bearing increase. The frictional torque needed to rotate the ball or journal also increases. When the coefficient of friction is assumed to be constant during wearing out, the frictional torque increases to a maximum of 1.273 times the frictional torque at zero wear.

  17. Design and construction of a tensile tester for the testing of simple composites

    Science.gov (United States)

    Borst, Mark A.; Spiegel, F. Xavier

    1994-01-01

    The following is a design for a tensile tester which will be used to test the tensile strength and anisotropic properties of simple composites. These simple composites are suspected to be anisotropic primarily in a single plane. When the composites undergo a tensile force, they will undergo deformation, causing movement either to the left or right. The composites are suspect due to their method of construction. Each sample has a single layer of unidirectional continuous fibers embedded in a rubbery resin. It has been well established that a serious limitation of unidirectional fiber composites is the very large in-plane anisotropy. The design presented here incorporates a single degree of freedom such that distortion (to the left or right) due to anisotropic tendencies may be measured. The device will spend the vast majority of its time in an undergraduate materials lab. As a result, ease of use and durability are valued more highly than research grade accuracy. Additional concerns focus on the fact that this machine will be built as a student project. Issues which are dealt with during this design include: specimen configuration or shape; a method of applying consistent, linear tension force; a method of gripping specimen without affecting its overall properties; a method of collecting data; repeatability of data; ease of use; ease of construction; and cost. After the device has been constructed, it will be used to test the simple composites which were fabricated in house. A comparison will be made between composites manufactured using aluminum screening as the strengthening fibers and those manufactured using fiberglass screening.

  18. Surface defects and temperature on atomic friction

    Energy Technology Data Exchange (ETDEWEB)

    Fajardo, O Y; Mazo, J J, E-mail: yovany@unizar.es [Departamento de Fisica de la Materia Condensada and Instituto de Ciencia de Materiales de Aragon, CSIC-Universidad de Zaragoza, 50009 Zaragoza (Spain)

    2011-09-07

    We present a theoretical study of the effect of surface defects on atomic friction in the stick-slip dynamical regime of a minimalistic model. We focus on how the presence of defects and temperature change the average properties of the system. We have identified two main mechanisms which modify the mean friction force of the system when defects are considered. As expected, defects change the potential profile locally and thus affect the friction force. But the presence of defects also changes the probability distribution function of the tip slip length and thus the mean friction force. We corroborated both effects for different values of temperature, external load, dragging velocity and damping. We also show a comparison of the effects of surface defects and surface disorder on the dynamics of the system. (paper)

  19. Shell Galaxies, Dynamical Friction, and Dwarf Disruption

    CERN Document Server

    Ebrova, Ivana; Canalizo, Gabriela; Bennert, Nicola; Jilkova, Lucie

    2009-01-01

    Using N-body simulations of shell galaxies created in nearly radial minor mergers, we investigate the error of collision dating, resulting from the neglect of dynamical friction and of gradual disruption of the cannibalized dwarf.

  20. Frictional Sliding without Geometrical Reflection Symmetry

    Science.gov (United States)

    Aldam, Michael; Bar-Sinai, Yohai; Svetlizky, Ilya; Brener, Efim A.; Fineberg, Jay; Bouchbinder, Eran

    2016-10-01

    The dynamics of frictional interfaces plays an important role in many physical systems spanning a broad range of scales. It is well known that frictional interfaces separating two dissimilar materials couple interfacial slip and normal stress variations, a coupling that has major implications on their stability, failure mechanism, and rupture directionality. In contrast, it is traditionally assumed that interfaces separating identical materials do not feature such a coupling because of symmetry considerations. We show, combining theory and experiments, that interfaces that separate bodies made of macroscopically identical materials but lack geometrical reflection symmetry generically feature such a coupling. We discuss two applications of this novel feature. First, we show that it accounts for a distinct, and previously unexplained, experimentally observed weakening effect in frictional cracks. Second, we demonstrate that it can destabilize frictional sliding, which is otherwise stable. The emerging framework is expected to find applications in a broad range of systems.

  1. Frictional sliding with geometrically broken reflection symmetry

    CERN Document Server

    Aldam, Michael; Svetlizky, Ilya; Brener, Efim A; Fineberg, Jay; Bouchbinder, Eran

    2016-01-01

    The dynamics of frictional interfaces play an important role in many physical systems spanning a broad range of scales. It is well-known that frictional interfaces separating two dissimilar materials couple interfacial slip and normal stress variations, a coupling that has major implications on their stability, failure mechanism and rupture directionality. In contrast, interfaces separating identical materials are traditionally assumed not to feature such a coupling due to symmetry considerations. We show, combining theory and experiments, that interfaces which separate bodies made of identical materials, but lack geometric reflection symmetry, generically feature such a coupling. We discuss two applications of this novel feature. First, we show that it accounts for a distinct and previously unexplained weakening effect in frictional cracks observed experimentally. Second, we demonstrate that it can destabilize frictional sliding which is otherwise stable. The emerging framework is expected to find applicatio...

  2. Permeability equipment for porous friction surfaces

    Science.gov (United States)

    Standiford, D. L.; Graul, R. A.; Lenke, L. R.

    1985-04-01

    Hydroplaning is the loss of traction between tires and pavement due to the presence of a layer of water. This loss of traction can result in loss of vehicle control. A porous friction surface (PFS) applied over an existing pavement permits the water to drain laterally and vertically away from the tire path, effectively lowering hydroplaning potential. Equipment used to measure pavement drainage (permeability) is discussed with respect to usage on porous friction surface. Background information on hydroplaning, flow theory, and PFS field performance as they are affected by permeability are also presented. Two dynamic test devices and four static devices are considered for measuring PFS permeability. Permeability tests are recommended to measure PFS permeability for maintenance purposes and construction control. Dynamic devices cited could possibly estimate hydroplaning potential; further research must be done to determine this. Permeability devices cannot be used to accurately estimate friction of a pavement surface, however, decreased permeability of a pavement infers a decrease in friction.

  3. Torque Control of Friction Stir Welding Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Longhurst Engineering, PLC and Vanderbilt University propose the innovation of torque control of friction stir welding (FSW) as a replacement to force control of...

  4. Transient effects in friction fractal asperity creep

    CERN Document Server

    Goedecke, Andreas

    2013-01-01

    Transient friction effects determine the behavior of a wide class of mechatronic systems. Classic examples are squealing brakes, stiction in robotic arms, or stick-slip in linear drives. To properly design and understand mechatronic systems of this type, good quantitative models of transient friction effects are of primary interest. The theory developed in this book approaches this problem bottom-up, by deriving the behavior of macroscopic friction surfaces from the microscopic surface physics. The model is based on two assumptions: First, rough surfaces are inherently fractal, exhibiting roughness on a wide range of scales. Second, transient friction effects are caused by creep enlargement of the real area of contact between two bodies. This work demonstrates the results of extensive Finite Element analyses of the creep behavior of surface asperities, and proposes a generalized multi-scale area iteration for calculating the time-dependent real contact between two bodies. The toolset is then demonstrated both...

  5. Friction Stir Processing of Cast Superalloys Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I effort examines the feasibility of an innovative fabrication technology incorporating sand casting and friction stir processing (FSP) for producing...

  6. Composites materials for friction and braking application

    Science.gov (United States)

    Crăciun, A. L.; Pinca-Bretotean, C.; Birtok-Băneasă, C.; Josan, A.

    2017-05-01

    The brake pads are an important component in the braking system of automotive. Materials used for brake pads should have stable and reliable frictional and wear properties under varying conditions of load, velocity, temperature and high durability. These factors must be satisfied simultaneously which makes it difficult to select effective brake pads material. The paper presents the results of the study for characterisation of the friction product used for automotive brake pads. In the study it was developed four frictional composites by using different percentages of coconut fibres (0%, 5%, 10%, 15%) reinforcement in aluminium matrix. The new composites tested in the laboratory, modelling appropriate percentage ratio between matrix and reinforcement volume and can be obtained with low density, high hardness properties, good thermal stability, higher ability to hold the compressive force and have a stable friction coefficient. These characteristics make them useful in automotive industry.

  7. Sliding without slipping under Coulomb friction: opening waves and inversion of frictional force

    CERN Document Server

    Yastrebov, Vladislav A

    2015-01-01

    An elastic layer slides on a rigid flat governed by Coulomb's friction law. We demonstrate that if the coefficient of friction is high enough, the sliding localizes within stick-slip pulses, which transform into opening waves propagating at intersonic speed in the direction of sliding or, for high Poisson's ratios, at supersonic speed in the opposite one. This sliding mode, characterized by small frictional dissipation, rapidly relaxes the shear elastic energy via stress waves and enables the contact surface slide ahead of the top one, resulting in inversion of the frictional force direction.

  8. A review of dynamics modelling of friction wedge suspensions

    Science.gov (United States)

    Wu, Qing; Cole, Colin; Spiryagin, Maksym; Sun, Yan Quan

    2014-11-01

    Three-piece bogies with friction wedge suspensions are the most widely used bogies in heavy haul trains. Fiction wedge suspensions play a key role in these wagon systems. This article reviews current techniques in dynamic modelling of friction wedge suspension with various motivations: to improve dynamic models of friction wedge suspensions so as to improve general wagon dynamics simulations; to seek better friction wedge suspension models for wagon stability assessments in complex train systems; to improve the modelling of other friction devices, such as friction draft gear. Relevant theories and friction wedge suspension models developed by using commercial simulation packages and in-house simulation packages are reviewed.

  9. Flexible Friction Stir Joining Technology

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Zhili [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lim, Yong Chae [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mahoney, Murray [MegaStir Technologies LLC, Orem, UT (United States); Sanderson, Samuel [MegaStir Technologies LLC, Orem, UT (United States); Larsen, Steve [MegaStir Technologies LLC, Orem, UT (United States); Steel, Russel [MegaStir Technologies LLC, Orem, UT (United States); Fleck, Dale [MegaStir Technologies LLC, Orem, UT (United States); Fairchild, Doug P [ExxonMobil, Upstream Research Company (URC), Houston, TX (United States); Wasson, Andrew J [ExxonMobil, Upstream Research Company (URC), Houston, TX (United States); Babb, Jon [MegaStir Technologies LLC, Orem, UT (United States); Higgins, Paul [MegaStir Technologies LLC, Orem, UT (United States)

    2015-07-23

    Reported herein is the final report on a U.S. Department of Energy (DOE) Advanced Manufacturing Office (AMO) project with industry cost-share that was jointly carried out by Oak Ridge National Laboratory (ORNL), ExxonMobil Upstream Research Company (ExxonMobil), and MegaStir Technologies (MegaStir). The project was aimed to advance the state of the art of friction stir welding (FSW) technology, a highly energy-efficient solid-state joining process, for field deployable, on-site fabrications of large, complex and thick-sectioned structures of high-performance and high-temperature materials. The technology innovations developed herein attempted to address two fundamental shortcomings of FSW: 1) the inability for on-site welding and 2) the inability to weld thick section steels, both of which have impeded widespread use of FSW in manufacturing. Through this work, major advance has been made toward transforming FSW technology from a “specialty” process to a mainstream materials joining technology to realize its pervasive energy, environmental, and economic benefits across industry.

  10. Linearization of friction effects in vibration of two rotating blades

    Directory of Open Access Journals (Sweden)

    Hajžman M.

    2013-06-01

    Full Text Available This paper is aimed at modelling of friction effects in blade shrouding which are realized by means of friction elements placed between blades. In order to develop a methodology of modelling, two blades with one friction element in between are considered only. Flexible blades fixed to a rotating disc are discretized by FEM using 1D Rayleigh beam elements derived in rotating space as well as the friction element modelled as a rigid body. The blades and the friction element are connected through two concurrent friction planes, where the friction forces arise on the basis of centrifugal force acting on the friction element. The linearization of friction is performed using the harmonic balance method to determine equivalent damping coefficients in dependence on the amplitudes of relative slip motion between the blades and the friction element. The methodology is applied to a model of two real blades and will be extended for the whole bladed disc with shrouding.

  11. Comparisons of friction models in bulk metal forming

    DEFF Research Database (Denmark)

    Tan, Xincai

    2002-01-01

    A friction model is one of the key input boundary conditions in finite element simulations. It is said that the friction model plays an important role in controlling the accuracy of necessary output results predicted. Among the various friction models, which one is of higher accuracy is still...... unknown and controversial. In this paper, finite element analyses applying five different friction models to experiments of upsetting of AA 6082 lubricated with four lubricants are presented. Frictional parameter values are determined by fitness of data of friction area ratio from finite element analysis...... to experimental results. It is found that calibration curves of the friction area ratio for all of the five chosen friction models used in the finite element simulation do fit the experimental results. Usually, calbration curves of the friction area ratio are more sensitive to friction at the tool...

  12. Comparing numerically exact and modelled static friction

    Directory of Open Access Journals (Sweden)

    Krengel Dominik

    2017-01-01

    Full Text Available Currently there exists no mechanically consistent “numerically exact” implementation of static and dynamic Coulomb friction for general soft particle simulations with arbitrary contact situations in two or three dimension, but only along one dimension. We outline a differential-algebraic equation approach for a “numerically exact” computation of friction in two dimensions and compare its application to the Cundall-Strack model in some test cases.

  13. THE FRICTION OF QUARTZ IN HIGH VACUUM

    Science.gov (United States)

    the effects of surface cleanliness . Ultra-high vacuums (to 10 to the minus 10th power torr) and high temperatures (to 350 deg C) were combined with...chemical cleaning and careful handling techniques to produce the maximum surface cleanliness . The coefficient of static friction under varying...on 30-40 mesh glass balls. The coefficient of friction of smooth quartz was found to vary from 0.1 to 1.0 depending on the surface cleanliness . The

  14. Network-Configurations of Dynamic Friction Patterns

    CERN Document Server

    Ghaffari, H O

    2012-01-01

    The complex configurations of dynamic friction patterns-regarding real time contact areas- are transformed into appropriate networks. With this transformation of a system to network space, many properties can be inferred about the structure and dynamics of the system. Here, we analyze the dynamics of static friction, i.e. nucleation processes, with respect to "friction networks". We show that networks can successfully capture the crack-like shear ruptures and possible corresponding acoustic features. We found that the fraction of triangles remarkably scales with the detachment fronts. There is a universal power law between nodes' degree and motifs frequency (for triangles, it reads T(k)\\proptok{\\beta} ({\\beta} \\approx2\\pm0.4)). We confirmed the obtained universality in aperture-based friction networks. Based on the achieved results, we extracted a possible friction law in terms of network parameters and compared it with the rate and state friction laws. In particular, the evolutions of loops are scaled with p...

  15. Role of Friction in Cold Ring Rolling

    Institute of Scientific and Technical Information of China (English)

    He YANG; Lianggang GUO; Mei ZHAN

    2005-01-01

    Cold ring rolling is an advanced but complex metal forming process under coupled effects with multi-factors, such as geometry sizes of rolls and ring blank, material, forming process parameters and friction, etc. Among these factors,friction between rolls and ring blank plays animportant role in keeping the stable forming of cold ring rolling. An analytical method was firstly presented for proximately determining the critical friction coefficient of stable forming and then a method was proposed to determine thecritical friction coefficient by combining analytical method with numerical simulation. And the influence of friction coefficient on the quality of end-plane and side spread of ring,rolling force, rolling moment and metal flow characteristic in the cold ring rolling process have been explored using the three dimensional (3D) numerical simulation based on the elastic-plastic dynamic finite element method (FEM)under the ABAQUS software environment, and the results show that increasing the friction on the contact surfaces between rolls and ring blank is useful not only for improving the stability of cold ring rolling but also for improving the geometry and dimension precision of deformed ring.

  16. Methods and devices used to measure friction in rolling

    DEFF Research Database (Denmark)

    Jeswiet, J.; Arentoft, Mogens; Henningsen, Poul

    2006-01-01

    a good understanding of the mechanisms at the interface and to be able to verify the friction and tribology models that exist, friction sensors are needed. Designing sensors to measure frictional stress in metal working has been pursued by many researchers. This paper surveys methods that have been used...... to measure friction in rolling in the past and discusses some of the recent sensor designs that can now be used to measure friction both in production situations and for research purposes....

  17. Numerical implementation of a state variable model for friction

    Energy Technology Data Exchange (ETDEWEB)

    Korzekwa, D.A. [Los Alamos National Lab., NM (United States); Boyce, D.E. [Cornell Univ., Ithaca, NY (United States)

    1995-03-01

    A general state variable model for friction has been incorporated into a finite element code for viscoplasticity. A contact area evolution model is used in a finite element model of a sheet forming friction test. The results show that a state variable model can be used to capture complex friction behavior in metal forming simulations. It is proposed that simulations can play an important role in the analysis of friction experiments and the development of friction models.

  18. Nano-Sized Grain Refinement Using Friction Stir Processing

    Science.gov (United States)

    2013-03-01

    friction stir weld is a very fine grain microstructure produced as a result of dynamic recrystallization. The friction stir ... Friction Stir Processing, Magnesium, Nano-size grains Abstract A key characteristic of a friction stir weld is a very fine grain microstructure...state process developed on the basis of the friction stir welding (FSW) technique invented by The Welding Institute (TWI) in 1991 [2]. During

  19. Friction Stir Processing for Efficient Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Mr. Christopher B. Smith; Dr. Oyelayo Ajayi

    2012-01-31

    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

  20. Apparatus for Sampling Surface Contamination

    Science.gov (United States)

    Wells, Mark

    2008-01-01

    An apparatus denoted a swab device has been developed as a convenient means of acquiring samples of contaminants from surfaces and suspending the samples in liquids. (Thereafter, the liquids can be dispensed, in controlled volumes, into scientific instruments for analysis of the contaminants.) The swab device is designed so as not to introduce additional contamination and to facilitate, simplify, and systematize the dispensing of controlled volumes of liquid into analytical instruments. The swab device is a single apparatus into which are combined all the equipment and materials needed for sampling surface contamination. The swab device contains disposable components stacked together on a nondisposable dispensing head. One of the disposable components is a supply cartridge holding a sufficient volume of liquid for one complete set of samples. (The liquid could be clean water or another suitable solvent, depending on the application.) This supply of liquid is sealed by Luer valves. At the beginning of a sampling process, the user tears open a sealed bag containing the supply cartridge. A tip on the nondisposable dispensing head is engaged with a Luer valve on one end of the supply cartridge and rotated, locking the supply cartridge on the dispensing head and opening the valve. The swab tip includes a fabric swab that is wiped across the surface of interest to acquire a sample. A sealed bag containing a disposable dispensing tip is then opened, and the swab tip is pushed into the dispensing tip until seated. The dispensing head contains a piston that passes through a spring-loaded lip seal. The air volume displaced by this piston forces the liquid out of the supply cartridge, over the swab, and into the dispensing tip. The piston is manually cycled to enforce oscillation of the air volume and thereby to cause water to flow to wash contaminants from the swab and cause the resulting liquid suspension of contaminants to flow into the dispensing tip. After several cycles

  1. Low friction and high strength of 316L stainless steel tubing for biomedical applications.

    Science.gov (United States)

    Amanov, Auezhan; Lee, Soo-Wohn; Pyun, Young-Sik

    2017-02-01

    We propose herein a nondestructive surface modification technique called ultrasonic nanocrystalline surface modification (UNSM) to increase the strength and to improve the tribological performance of 316L stainless steel (SS) tubing. Nanocrystallization along nearly the complete tube thickness of 200μm was achieved by UNSM technique that was confirmed by electron backscatter diffraction (EBSD). Nano-hardness of the untreated and UNSM-treated specimens was measured using a nanoindentation. Results revealed that a substantial increase in hardness was obtained for the UNSM-treated specimen that may be attributed to the nanocrystallization and refined grains. Stress-strain behavior of the untreated and UNSM-treated specimens was assessed by a 3-point bending test. It was found that the UNSM-treated specimen exhibited a much higher strength than that of the untreated specimen. In addition, the tribological behavior of the untreated and UNSM-treated specimens with an outer diameter (OD) of 1.6mm and an inner diameter (ID) of 1.2mm was investigated using a cylinder-on-cylinder (crossed tubes of equal radius) tribo-tester against itself under dry conditions at ambient temperature. The friction coefficient and wear resistance of the UNSM-treated specimen were remarkably improved compared to that of the untreated specimen. The significant increase in hardness after UNSM treatment is responsible for the improved friction coefficient and wear resistance of the tubing. Thus, the UNSM technique was found to be beneficial to improving the mechanical and tribological properties of 316L SS tubing for various potential biomedical applications, in particular for coronary artery stents.

  2. Manufacture of ultrasonic thickness measurement apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Ohba, Toshihiro; Yanagihara, Takao; Katoh, Chiaki; Hamada, Shozo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-09-01

    The demonstration test for evaluating reliability of the acid recovery evaporator at Rokkasho Reprocessing Plant has been carried out at JAERI. For the nondestructive measurement of the thickness of heat transfer tubes in the acid recovery evaporator and short tubes used in corrosion test, we have developed ultra sonic thickness measuring apparatus using immersion method with high resolution. This apparatus can measure and record tube thickness automatically with a personal computer. The results obtained by this apparatus are coincident with the results obtained by a destructive method using an optical microscope. (author)

  3. Frictional transfer and the self-organization phenomenon in the friction

    Science.gov (United States)

    Kolesnikov, I. V.; Manturov, D. S.

    2017-05-01

    The paper is devoted to the investigation of the mechanism and kinetics of the surface structures formation in the process of metal-polymer frictional contact. IR spectroscopy methods have showed that the formation kinetics of a frictionally transferred film is determined by the adhesion of the composite components and the direction of the electric field at the contact.

  4. Frictional stability-permeability relationships for fractures in shales: Friction-Permeability Relationships

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Yi [Department of Energy and Mineral Engineering, EMS Energy Institute, and G3 Center, Pennsylvania State University, University Park Pennsylvania USA; Elsworth, Derek [Department of Energy and Mineral Engineering, EMS Energy Institute, and G3 Center, Pennsylvania State University, University Park Pennsylvania USA; Department of Geosciences, EMS Energy Institute, and G3 Center, Pennsylvania State University, University Park Pennsylvania USA; Wang, Chaoyi [Department of Energy and Mineral Engineering, EMS Energy Institute, and G3 Center, Pennsylvania State University, University Park Pennsylvania USA; Ishibashi, Takuya [Department of Energy and Mineral Engineering, EMS Energy Institute, and G3 Center, Pennsylvania State University, University Park Pennsylvania USA; Fukushima Renewable Energy Institute, National Institute of Advanced Industrial Science and Technology, Koriyama Japan; Fitts, Jeffrey P. [Department of Civil and Environmental Engineering, Princeton University, Princeton New Jersey USA

    2017-01-01

    There is wide concern that fluid injection in the subsurface, such as for the stimulation of shale reservoirs or for geological CO2 sequestration (GCS), has the potential to induce seismicity that may change reservoir permeability due to fault slip. However, the impact of induced seismicity on fracture permeability evolution remains unclear due to the spectrum of modes of fault reactivation (e.g., stable versus unstable). As seismicity is controlled by the frictional response of fractures, we explore friction-stability-permeability relationships through the concurrent measurement of frictional and hydraulic properties of artificial fractures in Green River shale (GRS) and Opalinus shale (OPS). We observe that carbonate-rich GRS shows higher frictional strength but weak neutral frictional stability. The GRS fracture permeability declines during shearing while an increased sliding velocity reduces the rate of permeability decline. By comparison, the phyllosilicate-rich OPS has lower friction and strong stability while the fracture permeability is reduced due to the swelling behavior that dominates over the shearing induced permeability reduction. Hence, we conclude that the friction-stability-permeability relationship of a fracture is largely controlled by mineral composition and that shale mineral compositions with strong frictional stability may be particularly subject to permanent permeability reduction during fluid infiltration.

  5. Ultralow Friction in a Superconducting Magnetic Bearing

    Science.gov (United States)

    Bornemann, Hans J.; Siegel, Michael; Zaitsev, Oleg; Bareiss, Martin; Laschuetza, Helmut

    1996-01-01

    Passive levitation by superconducting magnetic bearings can be utilized in flywheels for energy storage. Basic design criteria of such a bearing are high levitation force, sufficient vertical and horizontal stability and low friction. A test facility was built for the measurement and evaluation of friction in a superconducting magnetic bearing as a function of operating temperature and pressure in the vacuum vessel. The bearing consists of a commercial disk shaped magnet levitated above single grain, melt-textured YBCO high-temperature superconductor material. The superconductor was conduction cooled by an integrated AEG tactical cryocooler. The temperature could be varied from 50 K to 80 K. The pressure in the vacuum chamber was varied from 1 bar to 10(exp -5) mbar. At the lowest pressure setting, the drag torque shows a linear frequency dependence over the entire range investigated (0 less than f less than 40 Hz). Magnetic friction, the frequency independent contribution, is very low. The frequency dependent drag torque is generated by molecular friction from molecule-surface collisions and by eddy currents. Given the specific geometry of the set-up and gas pressure, the molecular drag torque can be estimated. At a speed of 40 Hz, the coefficient of friction (drag-to-lift ratio) was measured to be mu = 1.6 x 10(exp -7) at 10(exp -5) mbar and T = 60 K. This is equivalent to a drag torque of 7.6 x 10(exp -10) Nm. Magnetic friction causes approx. 1% of the total losses. Molecular friction accounts for about 13% of the frequency dependent drag torque, the remaining 87% being due to eddy currents and losses from rotor unbalance. The specific energy loss is only 0.3% per hour.

  6. Gimballed Shoulders for Friction Stir Welding

    Science.gov (United States)

    Carter, Robert; Lawless, Kirby

    2008-01-01

    In a proposed improvement of tooling for friction stir welding, gimballed shoulders would supplant shoulders that, heretofore, have been fixedly aligned with pins. The proposal is especially relevant to self-reacting friction stir welding. Some definitions of terms, recapitulated from related prior NASA Tech Briefs articles, are prerequisite to a meaningful description of the proposed improvement. In friction stir welding, one uses a tool that includes (1) a rotating shoulder on top (or front) of the workpiece and (2) a pin that rotates with the shoulder and protrudes from the shoulder into the depth of the workpiece. In conventional friction stir welding, the main axial force exerted by the tool on the workpiece is reacted through a ridged backing anvil under (behind) the workpiece. When conventional friction stir welding is augmented with an auto-adjustable pin-tool (APT) capability, the depth of penetration of the pin into the workpiece is varied in real time by a position- or forcecontrol system that extends or retracts the pin as needed to obtain the desired effect. In self-reacting (also known as self-reacted) friction stir welding as practiced heretofore, there are two shoulders: one on top (or front) and one on the bottom (or back) of the workpiece. In this case, a threaded shaft protrudes from the tip of the pin to beyond the back surface of the workpiece. The back shoulder is held axially in place against tension by a nut on the threaded shaft. Both shoulders rotate with the pin and remain aligned coaxially with the pin. The main axial force exerted on the workpiece by the tool and front shoulder is reacted through the back shoulder and the threaded shaft into the friction-stir-welding machine head, so that a backing anvil is no longer needed. A key transmits torque between the bottom shoulder and the threaded shaft, so that the bottom shoulder rotates with the shaft. This concludes the prerequisite definitions of terms.

  7. Pulse measurement apparatus and method

    Science.gov (United States)

    Marciante, John R.; Donaldson, William R.; Roides, Richard G.

    2011-10-25

    An embodiment of the invention is directed to a pulse measuring system that measures a characteristic of an input pulse under test, particularly the pulse shape of a single-shot, nano-second duration, high shape-contrast optical or electrical pulse. An exemplary system includes a multi-stage, passive pulse replicator, wherein each successive stage introduces a fixed time delay to the input pulse under test, a repetitively-gated electronic sampling apparatus that acquires the pulse train including an entire waveform of each replica pulse, a processor that temporally aligns the replicated pulses, and an averager that temporally averages the replicated pulses to generate the pulse shape of the pulse under test. An embodiment of the invention is directed to a method for measuring an optical or an electrical pulse shape. The method includes the steps of passively replicating the pulse under test with a known time delay, temporally stacking the pulses, and temporally averaging the stacked pulses. An embodiment of the invention is directed to a method for increasing the dynamic range of a pulse measurement by a repetitively-gated electronic sampling device having a rated dynamic range capability, beyond the rated dynamic range of the sampling device; e.g., enhancing the dynamic range of an oscilloscope. The embodied technique can improve the SNR from about 300:1 to 1000:1. A dynamic range enhancement of four to seven bits may be achieved.

  8. Personal cooling apparatus and method

    Energy Technology Data Exchange (ETDEWEB)

    Siman-Tov, Moshe (Knoxville, TN); Crabtree, Jerry Allen (Knoxville, TN)

    2001-01-01

    A portable lightweight cooling apparatus for cooling a human body is disclosed, having a channeled sheet which absorbs sweat and/or evaporative liquid, a layer of highly conductive fibers adjacent the channeled sheet; and, an air-moving device for moving air through the channeled sheet, wherein the layer of fibers redistributes heat uniformly across the object being cooled, while the air moving within the channeled sheet evaporates sweat and/or other evaporative liquid, absorbs evaporated moisture and the uniformly distributed heat generated by the human body, and discharges them into the environment. Also disclosed is a method for removing heat generated by the human body, comprising the steps of providing a garment to be placed in thermal communication with the body; placing a layer of highly conductive fibers within the garment adjacent the body for uniformly distributing the heat generated by the body; attaching an air-moving device in communication with the garment for forcing air into the garment; removably positioning an exchangeable heat sink in communication with the air-moving device for cooling the air prior to the air entering the garment; and, equipping the garment with a channeled sheet in communication with the air-moving device so that air can be directed into the channeled sheet and adjacent the layer of fibers to expell heat and moisture from the body by the air being directed out of the channeled sheet and into the environment. The cooling system may be configured to operate in both sealed and unsealed garments.

  9. [Dynamic and cinematic evaluation of the function of bioprosthesis in the aortic position: tester of cardiac valves].

    Science.gov (United States)

    Bustamante, J; Santamaría, J; Infante, O; Flores, P; Juárez, A

    1996-01-01

    Twenty four pericardial valvular prostheses were tested in a valvular tester device. The valves considered were: 12 valves of the model that has being already in clinical use, manufactured in the Instituto Nacional de Cardiología "Ignacio Chávez", (INC II) and 12 valves of a model in an experimental stage, (PRT I.) The inner diameter in the two group considered were: 17, 19 and 21 mm. All the valves were tested in the aortic position in the valvular tester device. Behavior of the valvular prostheses were examined at various rates of pulsation, 60, 77, 105 and 159 per minute, with an ejection volume of 70 and 80 ml (range of flows between 4200 and 12720 ml min1). The pressure of the ventricular and aortic cameras were registered continuously, by external transducers, and in the other hand, the kinetic of the valves and the degree of opening were evaluated for direct view trough an special window. The grade of incompetence was too evaluated and expressed in percent of the stroke volume. The transvalvular pressure gradient was lower in INC II model valves, specially at moderate and high flows, and at same time had a largest functional area. The degree of incompetence was higher in the 19 and 21 mm diameter valvular subgroups than the same subgroups in the PRT I model. In relation to the 17 mm subgroup, significant differences were not find. The use of the valvular tester showed a basic utility in the hydrodynamic evaluation of the news bioprostheses design, and so in the quality control of the valves than has being manufacturing.

  10. New design and the manufacturing techniques of the main friction pair of frictional dampers

    Directory of Open Access Journals (Sweden)

    Aleksander GOLUBENKO

    2007-01-01

    Full Text Available The design of the main friction pair of the frictional oscillations damper of passenger car axle box stage suspension and its manufacturing techniques are described. The difference of the design of the main friction pair consists in replacement of a conicalcontact surface of the shpinton sleeve by a pyramidal surface as well as a cylindrical surface of the frictional slide block by a flat surface of the rectangular form. Technological ways of increase of strength and wear resistance were developed that allowed quantitatively to estimate a reserve of increase of strength and thermal wear resistance by methods of plastic deforming. With the purpose of increase of wear resistance and resource saving the new technology of producing the shpinton sleeve blank is offered by a method of cold die forging, and a frictional slide block – by hot dieforging.

  11. Inter-tester reliability of a new diagnostic classification system for patients with non-specific low back pain

    DEFF Research Database (Denmark)

    Petersen, Tom Erik; Olsen, Steen; Laslett, Mark

    2004-01-01

    pain were each examined by two physiotherapists. A total of four physiotherapists conducted the assessments. Examination findings were recorded independently by the two examiners. Percentage of agreement and kappa coefficients were calculated for each category. The overall rate of agreement was 72......% and the kappa coefficient was 0.62 for the mutually exclusive syndromes in the classification system. Agreement rates for each of the syndromes ranged from 74% to 100% and kappa coefficients ranged from 0.44 to 1.00. The findings suggest the inter-tester reliability of the system is acceptable. The relatively...

  12. Inter-tester reliability of a new diagnostic classification system for patients with non-specific low back pain

    DEFF Research Database (Denmark)

    Petersen, Tom Erik; Olsen, Steen; Laslett, Mark

    2004-01-01

    Most patients referred to physiotherapy with low back pain are without a precise medical diagnosis. Identification of subgroups of non-specific low back pain patients may improve clinical outcomes and research efficiency. A pathoanatomic classification system has been developed, classifying...... patients with non-specific low back pain into 12 different syndromes and three subcategories based on history and physical examination. The purpose of this study was to estimate the inter-tester reliability of clinical tests used as criteria for classifying patients. Ninety patients with chronic low back...

  13. Investigation of Specificity of Mechanical Properties of Hard Materials on Nanoscale with Use of SPM- Nanohardness Tester

    Science.gov (United States)

    Lvova, N. A.; Blank, V. D.; Gogolinskiy, K. V.; Kulibaba, V. F.

    2007-04-01

    Specifisities of deformation on nanoscale of hard brittle materials with the hardness exceeding 10 GP by means of scanning probe microscope - nanohardness tester "NanoScan" are investigated. It is found, that pile-up is forming at scratching of sample surface with use of diamond indenter. Heigh of this pile-up depends on hardness and elastic modulus of the material. Definition of the contact area without taking into account height of pile-up leads to an overestimation of hardness values. At scratching of silicon carbide surface a transition from plastic flow to fracture is found out. The results received allowed to estimate fracture toughness KIC for silicon carbide.

  14. Torsional Vibrations of a Cantilever with Lateral Friction in a Resonance Friction Microscope

    Institute of Scientific and Technical Information of China (English)

    CHEN Jian-Song; GE Yun; ZHANG Hui

    2012-01-01

    A model of fundamental torsional vibration of a cantilever with lateral friction is presented by using the harmonic balance method. The model demonstrates that the torsional vibration has close relations with the lateral friction threshold, the lateral contact stiffness and the torsional vibration amplitude of the cantilever. When the threshold is larger than a product of the stiffness and the vibration amplitude, the lateral friction is a linear force with the amplitude. If the lateral friction threshold is less than the product, the motions of the tip on the sample can be stick-slip or slip motions. The results are useful to optimize and to manipulate the fundamental flexural vibration of the piezo-cantilever, and give an insight into the tribological characterization of the interface in a resonance friction microscope.%A model of fundamental torsional vibration of a cantilever with lateral friction is presented by using the harmonic balance method.The model demonstrates that the torsional vibration has close relations with the lateral friction threshold,the lateral contact stiffness and the torsional vibration amplitude of the cantilever.When the threshold is larger than a product of the stiffness and the vibration amplitude,the lateral friction is a linear force with the amplitude.If the lateral friction threshold is less than the product,the motions of the tip on the sample can be stick-slip or slip motions.The results are useful to optimize and to manipulate the fundamental flexural vibration of the piezo-cantilever,and give an insight into the tribological characterization of the interface in a resonance friction microscope.

  15. Method and apparatus for measuring electromagnetic radiation

    Science.gov (United States)

    Been, J. F. (Inventor)

    1973-01-01

    An apparatus and method are described in which the capacitance of a semiconductor junction subjected to an electromagnetic radiation field is utilized to indicate the intensity or strength of the radiation.

  16. 莫来石纤维含量对陶瓷基摩擦材料摩擦磨损性能的影响%Effects of Mullite Fiber Content on Friction and Wear Properties of Ceramic-based Friction Material

    Institute of Scientific and Technical Information of China (English)

    王发辉; 刘莹

    2012-01-01

    Ceramic-based friction material with 0%-24% (mass fraction) mullite fiber reinforcement was prepared by nitrogen protection hot-pressing sintering. The effect of mullite fiber content on friction and wear properties of ceramic-based friction material was studied on the XD-MSM constant speed friction tester. The worn surfaces morphology after tests was observed by scanning electron mic'rosco-py (SEM), and wear mechanism was discussed. The results show that mullite fiber could increase friction coefficients of ceramic-based friction material, and with increasing mullite fiber contents, friction coefficients continuously increase. While the wear rates also increase with increasing mullite fiber contents at high temperature. The dominant wear mechanism of ceramic-based friction material without mullite fiber is brittle spalling and fatigue wear, accompanying with abrasive wear; the main wear type converts into adhesion wear and abrasive wear when adding mullite fiber into ceramic friction material.%利用氮气保护热压烧结法制备含0%~24%(质量分数)莫来石纤维增强陶瓷基摩擦材料,采用XD-MSM型定速摩擦试验机研究莫来石纤维含量对摩擦材料摩擦磨损性能的影响,借助于扫描电子显微镜观察实验后试样的磨损表面形貌,并探讨其磨损机理.结果表明:莫来石纤维的加入能够显著提高陶瓷基摩擦材料的摩擦因数,且随莫来石纤维含量增加而增大.在高温下,陶瓷基摩擦材料的磨损率随莫来石纤维含量增加而增大.未添加莫来石纤维的陶瓷基摩擦材料磨损形式主要是脆性脱落和疲劳磨损,伴有磨粒磨损;而添加莫来石纤维的陶瓷基摩擦材料磨损形式转化为黏着磨损和磨粒磨损.

  17. Effects of nano-LaF{sub 3} on the friction and wear behaviors of PTFE-based bonded solid lubricating coatings under different lubrication conditions

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Yulong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wan, Hongqi, E-mail: wanhq@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Chen, Lei, E-mail: chenlei@lzb.ac.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zhou, Huidi [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Chen, Jianmin, E-mail: chenjm@lzb.ac.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2016-09-30

    Highlights: • Nano-LaF{sub 3} was used to modify tribological behavior of PTFE bonded solid lubricating coating. • The tribological properties of lubricating coatings were investigated under different lubrication conditions. • The modified PTFE bonded coating exhibited superior tribological performance both under two kinds of lubrication conditions. - Abstract: Influence of nanometer lanthanum fluoride (nano-LaF{sub 3}) on the tribological behaviors of polytetrafluoroethylene (PTFE) bonded solid lubricating coatings were investigated using a ring-on-block friction-wear tester under dry friction and RP-3 jet fuel lubrication conditions. The worn surfaces and transfer films formed on the counterpart steel rings were observed by scanning electron microscope (SEM) and optical microscope (OM), respectively. The microstructures of the nano-LaF{sub 3} modified coatings and the distribution states of nano-LaF{sub 3} were studied by field-emission scanning electron microscope (FESEM) and transmission electron microscopy (TEM), respectively. The results show that incorporation of nano-LaF{sub 3} improves the microhardness and the friction-reduced and anti-wear abilities of PTFE bonded solid lubricating coatings. The wear life of the modified coating is about 6 times longer than that of the coating without nano-LaF{sub 3} filler at a relatively low applied load (200 N) and rotary speed (1000 rev/min) under dry friction condition. The friction coefficient and wear life of the modified coating decrease with increase of applied load under dry friction, but the friction coefficient has hardly any variation and wear life decreases under RP-3 jet fuel lubrication condition. In addition, the friction coefficient of the modified coating reduces with the rotary speed increasing under dry sliding but has little change under RP-3 lubrication, the wear life increases firstly and then decreases. The results indicated that the wear failure mechanism is dominated by applied load

  18. Time dependent friction in a free gas

    Science.gov (United States)

    Fanelli, Cristiano; Sisti, Francesco; Stagno, Gabriele V.

    2016-03-01

    We consider a body moving in a perfect gas, described by the mean-field approximation and interacting elastically with the body, we study the friction exerted by the gas on the body fixed at constant velocities. The time evolution of the body in this setting was studied in Caprino et al. [Math. Phys. 264, 167-189 (2006)], Caprino et al. [Math. Models Methods Appl. Sci. 17, 1369-1403 (2007)], and Cavallaro [Rend. Mat. Appl. 27, 123-145 (2007)] for object with simple shape; the first study where a simple kind of concavity was considered was in Sisti and Ricciuti [SIAM J. Math. Anal. 46, 3759-3611 (2014)], showing new features in the dynamic but not in the friction term. The case of more general shape of the body was left out for further difficulties, and we believe indeed that there are actually non-trivial issues to be faced for these more general cases. To show this and in the spirit of getting a more realistic perspective in the study of friction problems, in this paper, we focused our attention on the friction term itself, studying its behavior on a body with a more general kind of concavity and fixed at constant velocities. We derive the expression of the friction term for constant velocities, we show how it is time dependent, and we give its exact estimate in time. Finally, we use this result to show the absence of a constant velocity in the actual dynamic of such a body.

  19. Velocity Dependence of Friction of Confined Hydrocarbons

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Samoilov, Vladimir N.; Persson, Bo N. J.

    2010-01-01

    We present molecular dynamics friction calculations for confined hydrocarbon “polymer” solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: (a) polymer sliding against a hard substrate and (b) polymer sliding on polymer. We discuss the velocity dependence of the f......We present molecular dynamics friction calculations for confined hydrocarbon “polymer” solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: (a) polymer sliding against a hard substrate and (b) polymer sliding on polymer. We discuss the velocity dependence...... in the polymer film is always close to the thermostat temperature. In the first setup (a), for hydrocarbons with molecular lengths from 60 to 1400 carbon atoms, the shear stresses are nearly independent of molecular length, but for the shortest hydrocarbon C20H42 the frictional shear stress is lower. In all...... cases the frictional shear stress increases monotonically with the sliding velocity. For polymer sliding on polymer (case b) the friction is much larger, and the velocity dependence is more complex. For hydrocarbons with molecular lengths from 60 to 140 C atoms, the number of monolayers of lubricant...

  20. Assessing the clarity of friction ridge impressions.

    Science.gov (United States)

    Hicklin, R Austin; Buscaglia, JoAnn; Roberts, Maria Antonia

    2013-03-10

    The ability of friction ridge examiners to correctly discern and make use of the ridges and associated features in finger or palm impressions is limited by clarity. The clarity of an impression relates to the examiner's confidence that the presence, absence, and attributes of features can be correctly discerned. Despite the importance of clarity in the examination process, there have not previously been standard methods for assessing clarity in friction ridge impressions. We introduce a process for annotation, analysis, and interchange of friction ridge clarity information that can be applied to latent or exemplar impressions. This paper: (1) describes a method for evaluating the clarity of friction ridge impressions by using color-coded annotations that can be used by examiners or automated systems; (2) discusses algorithms for overall clarity metrics based on manual or automated clarity annotation; and (3) defines a method of quantifying the correspondence of clarity when comparing a pair of friction ridge images, based on clarity annotation and resulting metrics. Different uses of this approach include examiner interchange of data, quality assurance, metrics, and as an aid in automated fingerprint matching.

  1. Apparatus, System, And Method For Roadway Monitoring

    KAUST Repository

    Claudel, Christian G.

    2015-06-02

    An apparatus, system, and method for monitoring traffic and roadway water conditions. Traffic flow and roadway flooding is monitored concurrently through a wireless sensor network. The apparatus and system comprises ultrasound rangefinders monitoring traffic flow, flood water conditions, or both. Routing information may be calculated from the traffic conditions, such that routes are calculated to avoid roadways that are impassable or are slow due to traffic conditions.

  2. Apparatus and methods for detecting chemical permeation

    Science.gov (United States)

    Vo-Dinh, Tuan

    1994-01-01

    Apparatus and methods for detecting the permeation of hazardous or toxic chemicals through protective clothing are disclosed. The hazardous or toxic chemicals of interest do not possess the spectral characteristic of luminescence. The apparatus and methods utilize a spectrochemical modification technique to detect the luminescence quenching of an indicator compound which upon permeation of the chemical through the protective clothing, the indicator is exposed to the chemical, thus indicating chemical permeation.

  3. Materials processing apparatus development for fluoride glass

    Science.gov (United States)

    Smith, Guy A.; Kosten, Sue; Workman, Gary L.

    1994-01-01

    Fluoride glasses have great potential for optical fiber communications due to the high transmittance when no microcrystallites occur during drawing operations. This work has developed apparatus to test the occurrence of microcrystallites during recrystallization in reduced gravity on the KC-135. The apparatus allows fluoride glass fiber, such as ZBLAN, to be melted and recrystallized during both the low and high g portions the parabolic flight.

  4. 29 CFR 1910.219 - Mechanical power-transmission apparatus.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Mechanical power-transmission apparatus. 1910.219 Section... Mechanical power-transmission apparatus. (a) General requirements. (1) This section covers all types and... apparatus located in basements. All mechanical power transmission apparatus located in basements,...

  5. Friction and wear in polymer-based materials

    CERN Document Server

    Bely, V A; Petrokovets, M I

    1982-01-01

    Friction and Wear in Polymer-Based Materials discusses friction and wear problems in polymer-based materials. The book is organized into three parts. The chapters in Part I cover the basic laws of friction and wear in polymer-based materials. Topics covered include frictional interaction during metal-polymer contact and the influence of operating conditions on wear in polymers. The chapters in Part II discuss the structure and frictional properties of polymer-based materials; the mechanism of frictional transfer when a polymer comes into contact with polymers, metals, and other materials; and

  6. Benchmarking of direct and indirect friction tests in micro forming

    DEFF Research Database (Denmark)

    Eriksen, Rasmus Solmer; Calaon, Matteo; Arentoft, M.

    2012-01-01

    The sizeable increase in metal forming friction at micro scale, due to the existence of size effects, constitutes a barrier to the realization of industrial micro forming processes. In the quest for improved frictional conditions in micro scale forming operations, friction tests are applied...... to qualify the tribological performance of the particular forming scenario. In this work the application of a simulative sliding friction test at micro scale is studied. The test setup makes it possible to measure the coefficient of friction as a function of the sliding motion. The results confirm a sizeable...... increase in the coefficient of friction when the work piece size is scaled down. © (2012) Trans Tech Publications....

  7. Frictional and hydraulic behaviour of carbonate fault gouge during fault reactivation - An experimental study

    Science.gov (United States)

    Delle Piane, Claudio; Giwelli, Ausama; Clennell, M. Ben; Esteban, Lionel; Nogueira Kiewiet, Melissa Cristina D.; Kiewiet, Leigh; Kager, Shane; Raimon, John

    2016-10-01

    We present a novel experimental approach devised to test the hydro-mechanical behaviour of different structural elements of carbonate fault rocks during experimental re-activation. Experimentally faulted core plugs were subject to triaxial tests under water saturated conditions simulating depletion processes in reservoirs. Different fault zone structural elements were created by shearing initially intact travertine blocks (nominal size: 240 × 110 × 150 mm) to a maximum displacement of 20 and 120 mm under different normal stresses. Meso-and microstructural features of these sample and the thickness to displacement ratio characteristics of their deformation zones allowed to classify them as experimentally created damage zones (displacement of 20 mm) and fault cores (displacement of 120 mm). Following direct shear testing, cylindrical plugs with diameter of 38 mm were drilled across the slip surface to be re-activated in a conventional triaxial configuration monitoring the permeability and frictional behaviour of the samples as a function of applied stress. All re-activation experiments on faulted plugs showed consistent frictional response consisting of an initial fast hardening followed by apparent yield up to a friction coefficient of approximately 0.6 attained at around 2 mm of displacement. Permeability in the re-activation experiments shows exponential decay with increasing mean effective stress. The rate of permeability decline with mean effective stress is higher in the fault core plugs than in the simulated damage zone ones. It can be concluded that the presence of gouge in un-cemented carbonate faults results in their sealing character and that leakage cannot be achieved by renewed movement on the fault plane alone, at least not within the range of slip measureable with our apparatus (i.e. approximately 7 mm of cumulative displacement). Additionally, it is shown that under sub seismic slip rates re-activated carbonate faults remain strong and no frictional

  8. Characterization of boron carbide particulate reinforced in situ copper surface composites synthesized using friction stir processing

    Energy Technology Data Exchange (ETDEWEB)

    Sathiskumar, R., E-mail: sathiscit2011@gmail.com [Department of Mechanical Engineering, Coimbatore Institute of Technology, Coimbatore, 641 014 Tamil Nadu (India); Murugan, N., E-mail: murugan@cit.edu.in [Department of Mechanical Engineering, Coimbatore Institute of Technology, Coimbatore, 641 014 Tamil Nadu (India); Dinaharan, I., E-mail: dinaweld2009@gmail.com [Department of Mechanical Engineering, V V College of Engineering, Tisaiyanvilai, 627 657 Tamil Nadu (India); Vijay, S.J., E-mail: vijayjoseph@karunya.edu [Centre for Research in Metallurgy (CRM), School of Mechanical Sciences, Karunya University, Coimbatore, 641 114 Tamil Nadu (India)

    2013-10-15

    Friction stir processing has evolved as a novel solid state technique to fabricate surface composites. The objective of this work is to apply the friction stir processing technique to fabricate boron carbide particulate reinforced copper surface composites and investigate the effect of B{sub 4}C particles and its volume fraction on microstructure and sliding wear behavior of the same. A groove was prepared on 6 mm thick copper plates and packed with B{sub 4}C particles. The dimensions of the groove was varied to result in five different volume fractions of B{sub 4}C particles (0, 6, 12, 18 and 24 vol.%). A single pass friction stir processing was done using a tool rotational speed of 1000 rpm, travel speed of 40 mm/min and an axial force of 10 kN. Metallurgical characterization of the Cu/B{sub 4}C surface composites was carried out using optical microscope and scanning electron microscope. The sliding wear behavior was evaluated using a pin-on-disk apparatus. Results indicated that the B{sub 4}C particles significantly influenced the area, dispersion, grain size, microhardness and sliding wear behavior of the Cu/B{sub 4}C surface composites. When the volume fraction of B{sub 4}C was increased, the wear mode changed from microcutting to abrasive wear and wear debris was found to be finer. Highlights: • Fabrication of Cu/B{sub 4}C surface composite by friction stir processing • Analyzing the effect of B{sub 4}C particles on the properties of Cu/B4C surface composite • Increased volume fraction of B{sub 4}C particles reduced the area of surface composite. • Increased volume fraction of B{sub 4}C particles enhanced the microhardness and wear rate. • B{sub 4}C particles altered the wear mode from microcutting to abrasive.

  9. Frictional melting dynamics in the upper conduit: A chemical answer to a complex physical question

    Science.gov (United States)

    Henton De Angelis, S.; Lavallee, Y.; Kendrick, J. E.; Hornby, A.; von Aulock, F. W.; Clesham, S.; Hirose, T.; Perugini, D.

    2013-12-01

    During volcanic eruptions the generation of frictional heat along the walls of the shallow conduit leads to melting of the rocks along the slip interface. Frictional melting has previously been described as a process out of thermodynamic equilibrium, but upon slip and mingling of the melt batches, homogeneity can be achieved, and may have an h important rheological control on the dynamics of slip. To test melt homogenization in the frictional melt zones of volcanic conduits we performed constant-rate slip experiments under controlled stress conditions using a high-velocity rotary shear apparatus. Volcanic dome samples from three different volcanoes (Volcán De Colima, Soufrière Hills Volcano and Santiaguito Volcano) were investigated. Each sample was subjected to a stress of 1 MPa and slip rate of 1 m/s. For each sample set 5 experiments were conducted: 1) experiment stopped at the onset of melting; 2) experiment stopped on the formation of a full melt layer; 3) experiment stopped after 5m of slip at steady state conditions; 4) experiment stopped after 10m of slip at steady state conditions; 5) experiment stopped after 15m of slip at steady state conditions. We analyzed the resulting proto-melt zones using micron sized X-ray spectroscopy in the high-brightness synchrotron beamline I18 (at Diamond Light Source UK). Particular focus was given to the concentration variance analysis of Rare Earth Elements as their mobilities can be used to precisely quantify the degree and timescale of homogenisation involved during frictional melting. This study refines our understanding of the chemical process of melting and mixing which carry important consequences for the rheological control on the physical dynamics of slip.

  10. Improvements to the APEX apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I.; Back, B.B.; Betts, R.R. [and others

    1995-08-01

    A number of technical issues led us to rework extensively the APEX apparatus in summer 1994. During the earlier runs, a significant fraction of the 432 silicon detector elements showed degraded resolution such that they had to be excluded from the final analysis in software. The effect of this is to reduce the efficiency of APEX and possibly also to introduce holes in the acceptance which, for some perhaps exotic scenarios, might reduce the acceptance to an unacceptably low level. Also, the energy thresholds below which it is not possible to generate timing information from the silicon detectors, were high enough that the low-energy acceptance of APEX was compromised to a significant extent. The origins of these difficulties were in part due to degraded performance of the silicon detectors themselves, problems with the silicon cooling systems and electronics problems. Both silicon arrays were disassembled and sub-standard detectors replaced, all detectors were also cleaned with the result that all detectors now performed at the specified values of leakage current. The silicon cooling systems were disassembled and rebuilt with the result that many small leaks were fixed. Defective electronics channels were repaired or replaced. The rotating target wheel was also improved with the installation of new bearings and a computer-controlled rotation and readout system. The rebuilt wheel can now run at speeds up to 900 rpm for weeks on end without breakdown. The target wheel and associated beam sweeping now work extremely well so that low-melting-point targets such as Pb and In can be used in quite intense beams without melting.

  11. Direct friction measurement in draw bead testing

    DEFF Research Database (Denmark)

    Olsson, David Dam; Bay, Niels; Andreasen, Jan Lasson

    2005-01-01

    The application of draw beads in sheet metal stamping ensures controlled drawing-in of flange parts. Lubrication conditions in draw beads are severe due to sliding under simultaneous bending. Based on the original draw bead test design by Nine [1] comprehensive studies of friction in draw beads...... have been reported in literature. A major drawback in all these studies is that friction is not directly measured, but requires repeated measurements of the drawing force with and without relative sliding between the draw beads and the sheet material. This implies two tests with a fixed draw bead tool...... and a freely rotating tool respectively, an approach, which inevitably implies large uncertainties due to scatter in the experimental conditions. In order to avoid this problem a new draw bead test is proposed by the authors measuring the friction force acting on the tool radius directly by a build...

  12. Hyperstaticity and loops in frictional granular packings

    Science.gov (United States)

    Tordesillas, Antoinette; Lam, Edward; Metzger, Philip T.

    2009-06-01

    The hyperstatic nature of granular packings of perfectly rigid disks is analyzed algebraically and through numerical simulation. The elementary loops of grains emerge as a fundamental element in addressing hyperstaticity. Loops consisting of an odd number of grains behave differently than those with an even number. For odd loops, the latent stresses are exterior and are characterized by the sum of frictional forces around each loop. For even loops, the latent stresses are interior and are characterized by the alternating sum of frictional forces around each loop. The statistics of these two types of loop sums are found to be Gibbsian with a "temperature" that is linear with the friction coefficient μ when μ<1.

  13. CAM/LIFTER forces and friction

    Science.gov (United States)

    Gabbey, D. J.; Lee, J.; Patterson, D. J.

    1992-02-01

    This report details the procedures used to measure the cam/lifter forces and friction. The present effort employed a Cummins LTA-10, and focuses on measurements and dynamic modeling of the injector train. The program was sponsored by the US Department of Energy in support of advanced diesel engine technology. The injector train was instrumented to record the instantaneous roller speed, roller pin friction torque, pushrod force, injector link force, and cam speed. These measurements, together with lift profiles for pushrod and injector link displacement, enabled the friction work loss in the injector train to be determined. Other significant design criteria such as camshaft roller follower slippage and maximum loads on components were also determined. Future efforts will concentrate on the dynamic model, with tests run as required for correlation.

  14. Physics of Friction in Disposable Plastic Syringes

    Science.gov (United States)

    Liebmann-Vinson, A.; Vogler, E. A.; Martin, D. A.; Montgomery, D. B.; Sugg, H. W.; Monahan, L. A.

    1997-03-01

    Nosocomial applications of disposable plastic syringes demand excellent frictional behavior with no stick-slip over a broad velocity range and, simultaneously, a tight seal between stopper and barrel. However, when used in syringe pumps at slow injection speeds, stick-slip motion is frequently observed and high "break-out" forces are often necessary to initiate plunger movement after extended storage times. We have traced this frictional behavior to a velocity-dependent interaction between the elastomeric stopper and the plastic syringe barrel mediated by the syringe lubricant, almost universally a polydimethyl siloxane fluid. Lubricant properties were altered by crosslinking the surface of the silicone oil in an oxygen plasma. Changes in surface chemistry and morphology of the crosslinked oil were correlated with changes in frictional performance.

  15. Direct friction measurement in draw bead testing

    DEFF Research Database (Denmark)

    Olsson, David Dam; Bay, Niels; Andreasen, Jan Lasson

    2005-01-01

    have been reported in literature. A major drawback in all these studies is that friction is not directly measured, but requires repeated measurements of the drawing force with and without relative sliding between the draw beads and the sheet material. This implies two tests with a fixed draw bead tool...... and a freely rotating tool respectively, an approach, which inevitably implies large uncertainties due to scatter in the experimental conditions. In order to avoid this problem a new draw bead test is proposed by the authors measuring the friction force acting on the tool radius directly by a build......-in piezoelectric torque transducer. This technique results in a very sensitive measurement of friction, which furthermore enables recording of lubricant film breakdown as function of drawing distance. The proposed test is validated in an experimental investigation of the influence of lubricant viscosity...

  16. Friction enhancement in concertina locomotion of snakes.

    Science.gov (United States)

    Marvi, Hamidreza; Hu, David L

    2012-11-07

    Narrow crevices are challenging terrain for most organisms and biomimetic robots. Snakes move through crevices using sequential folding and unfolding of their bodies in the manner of an accordion or concertina. In this combined experimental and theoretical investigation, we elucidate this effective means of moving through channels. We measure the frictional properties of corn snakes, their body kinematics and the transverse forces they apply to channels of varying width and inclination. To climb channels inclined at 60°, we find snakes use a combination of ingenious friction-enhancing techniques, including digging their ventral scales to double their frictional coefficient and pushing channel walls transversely with up to nine times body weight. Theoretical modelling of a one-dimensional n-linked crawler is used to calculate the transverse force factor of safety: we find snakes push up to four times more than required to prevent sliding backwards, presumably trading metabolic energy for an assurance of wall stability.

  17. Friction enhancement in concertina locomotion of snakes

    Science.gov (United States)

    Marvi, Hamidreza; Hu, David L.

    2012-01-01

    Narrow crevices are challenging terrain for most organisms and biomimetic robots. Snakes move through crevices using sequential folding and unfolding of their bodies in the manner of an accordion or concertina. In this combined experimental and theoretical investigation, we elucidate this effective means of moving through channels. We measure the frictional properties of corn snakes, their body kinematics and the transverse forces they apply to channels of varying width and inclination. To climb channels inclined at 60°, we find snakes use a combination of ingenious friction-enhancing techniques, including digging their ventral scales to double their frictional coefficient and pushing channel walls transversely with up to nine times body weight. Theoretical modelling of a one-dimensional n-linked crawler is used to calculate the transverse force factor of safety: we find snakes push up to four times more than required to prevent sliding backwards, presumably trading metabolic energy for an assurance of wall stability. PMID:22728386

  18. Static and dynamic friction of hierarchical surfaces

    Science.gov (United States)

    Costagliola, Gianluca; Bosia, Federico; Pugno, Nicola M.

    2016-12-01

    Hierarchical structures are very common in nature, but only recently have they been systematically studied in materials science, in order to understand the specific effects they can have on the mechanical properties of various systems. Structural hierarchy provides a way to tune and optimize macroscopic mechanical properties starting from simple base constituents and new materials are nowadays designed exploiting this possibility. This can be true also in the field of tribology. In this paper we study the effect of hierarchical patterned surfaces on the static and dynamic friction coefficients of an elastic material. Our results are obtained by means of numerical simulations using a one-dimensional spring-block model, which has previously been used to investigate various aspects of friction. Despite the simplicity of the model, we highlight some possible mechanisms that explain how hierarchical structures can significantly modify the friction coefficients of a material, providing a means to achieve tunability.

  19. Adhesion and friction of thin metal films

    Science.gov (United States)

    Buckley, D. H.

    1976-01-01

    Sliding friction experiments were conducted in vacuum with thin films of titanium, chromium, iron, and platinum sputter deposited on quartz or mica substrates. A single crystal hemispherically tipped gold slider was used in contact with the films at loads of 1.0 to 30.0 and at a sliding velocity of 0.7 mm/min at 23 C. Test results indicate that the friction coefficient is dependent on the adhesion of two interfaces, that between the film and its substrate and the slider and the film. There exists a relationship between the percent d bond character of metals in bulk and in thin film form and the friction coefficient. Oxygen can increase adhesive bonding of a metal film (platinum) to a substrate.

  20. Combining ability and heritability estimates of main agronomic characters in rapeseed breeding lines using line × tester analysis

    Directory of Open Access Journals (Sweden)

    Rameeh Valiollah

    2012-01-01

    Full Text Available To estimate the general and specific combining ability (GCA and SCA effects of plant height, yield components, seed yield and oil content, three testers and six lines of spring type of rapeseed varieties were crossed using line × tester fashion. Significant mean squares of parents and crosses for all the traits indicated significant genetic variation among the parents and their F1 crosses. Significant mean squares of parents vs crosses revealed significant average heterosis for all the traits except seeds per pod, 1000-seed weight and oil content. High narrow-sense heritability estimates for all the traits except seeds per pod, indicating the importance of additive genetic effects for these traits. Due to more importance of additive genetic effects for most of the traits, only a few of the crosses exhibited significant SCA effects. A significant positive correlation between seed yield and some of yield components including pods on main axis, pods per plant and 1000-seed weight indicates that these traits can be used as suitable selection criteria for improving of seed yield. The crosses including Opt × R01, RG06 × R01, RG06 × R08 and RGS3 × R08 with 3241.91, 3213.68, 3334.28 and 3237.45 kg ha-1 of seed yield detected as prior combinations for improving of this trait and all of these combinations had also positive SCA effect for this trait.

  1. Relating the octane numbers of fuels to ignition delay times measured in an ignition quality tester (IQT)

    KAUST Repository

    Naser, Nimal

    2016-09-21

    A methodology for estimating the octane index (OI), the research octane number (RON) and the motor octane number (MON) using ignition delay times from a constant volume combustion chamber with liquid fuel injection is proposed by adopting an ignition quality tester. A baseline data of ignition delay times were determined using an ignition quality tester at a charge pressure of 21.3 bar between 770 and 850 K and an equivalence ratio of 0.7 for various primary reference fuels (PRFs, mixtures of isooctane and n-heptane). Our methodology was developed using ignition delay times for toluene reference fuels (mixtures of toluene and n-heptane). A correlation between the OI and the ignition delay time at the initial charge temperature enabled the OI of non-PRFs to be predicted at specified temperatures. The methodology was validated using ignition delay times for toluene primary reference fuels (ternary mixtures of toluene, iso-octane, and n-heptane), fuels for advanced combustion engines (FACE) gasolines, and certification gasolines. Using this methodology, the RON, the MON, and the octane sensitivity were estimated in agreement with values obtained from standard test methods. A correlation between derived cetane number and RON is also provided. (C) 2016 Elsevier Ltd. All rights reserved.

  2. Biplot Analysis of Genotype by Environment for Cooking Quality in Hybrid Rice:A Tool for Line × Tester Data

    Institute of Scientific and Technical Information of China (English)

    Mohammad H. FOTOKIAN; Kayvan AGAHI

    2014-01-01

    A study of combining ability for improving rice cooking quality was carried out via genotype plus genotype × environment (GGE) biplot. Four restorer lines and three male sterile lines were used to obtain F1 in a line × tester trial at the Rice Research Institute, Amol, Iran in 2009. GGE biplot analysis showed that Neda and IR56 were the best general combiners for amylose content (AC), whereas Nemat and IR28 had the highest general combining ability (GCA) effects for gelatinization temperature (GT), and IR58 and IR59 showed the highest GCA effects in terms of gel consistency (GC). Meanwhile, IR58 and IR59 showed large specific combining ability (SCA) effects for AC, while Neda and SA13 had high SCA effects for GT. Nemat and IR28 had large SCA effects for GC. Because intermediate levels of AC, GT and GC are ideal, Nemat × IR59 was considered as the best possible cross. Based on these results, the GGE biplot showed good potential for identifying suitable parents, heterotic crosses and the best hybrids in line × tester data.

  3. Frictional Behavior of Anorthite and Quartz at High Pressure and High Temperature Conditions

    Science.gov (United States)

    Arai, T.; Masuda, K.; Fujimoto, K.; Shigematsu, N.; Ohtani, T.; Sumii, T.; Okuyama, Y.

    2002-12-01

    Most of earthquakes in the crust occurred at the depth of 5 to 20km, and the distribution of mainshocks matches the base of this zone, where is considered to be consistent with brittle-ductile transition zone. The lower boundary on seismicity results from a switch from velocity weakening to velocity strengthening of friction with increasing temperature. The physical properties of rocks associated with elevated temperatures were determined by many frictional experiments. In these experimental studies, quartz, which controls the rock strength at brittle-ductile transition zone, was generally used. On the other hand, frictional experiment with feldspar is very few in spite of dominant phase in the crust, because feldspar behaves in a brittle manner at greenshist facies. However, recent studies indicate fine-grained plagioclase (1um) contributed deformation process largely at the Hatagawa fault zone, northeast Japan, where is considered to have been brittle-ductile transition zone in the past. In order to understand the source processes of earthquakes, it is important to evaluate the physical properties of fine grained plagioclace as well as those of quartz. In this study, we conducted frictional experiments by using anorthite and quartz gouges under high pressure and high temperature in a triaxial apparatus, and compared frictional behaviors of two minerals with elevated temperature. Temperature varied from room temperature to 800°C. Fine- (1-10um,1um) and coarse-grained (50um, 100um) samples were prepared to evaluate the effect of different grain size as observed Hatagawa fault zone. The samples were put between upper and lower sawcut cylinders (20mm diameter x 40mm long). The sawcut was oriented at 30° to the loading axis. These were jacketed with thin sleeves of annealed Cu. Pore fluids accelerated deformation process of Hatagawa mylonite at higher temperature than 600°C under the same effective confining pressure (Masuda et al., presented in this meeting

  4. Frictional Properties of Feldspar and Quartz at the Temperatures of Seismogenic Zone

    Science.gov (United States)

    Arai, T.; Masuda, K.; Takahashi, M.; Fujimoto, K.; Shigematsu, N.; Sumii, T.; Okuyama, Y.

    2003-12-01

    Most of earthquakes in the crust occurred at the depth of 5 to 20km, and temperatures of 100 to 350° C. The physical properties of rocks at around these temperatures were determined by many frictional experiments. These results indicated the velocity dependence of steady state friction (a-b) was switched from velocity weakening ( seismic slip ) to velocity strengthening ( aseismic slip ) at around 350° C in the wet condition. In these experimental studies, granites were generally used. On the other hand, it is important to evaluate and to compare the physical properties of each mineral which composed of crustal rocks, for example feldspar and quartz, in order to understand the source processes of earthquakes in detail. In this study, we conducted frictional experiments by using albite, anorthite, and quartz gouges ( about 3μ m diameter ) under high pressure and high temperature in a triaxial apparatus, and compared frictional behaviors of three minerals with elevated temperature under the wet and dry conditions. These experiments were conducted by the velocity-stepping test. Temperature varied from room temperature to 600° C. In the dry conditions, experiments were conducted under the confining pressure of 150MPa. In the wet conditions, pore water pressure was applied up to 50MPa under the confining pressure of 200MPa. Sample was put between upper and lower sawcut alumina cylinders ( 20mm diameter x 40mm long ). The sawcut was oriented at 30° to the loading axis. These were jacketed with thin sleeves of annealed Cu. The values for a-b of quartz and albite were positive under the dry condition from room temperature to 600° C. On the other hand, those values of albite and quartz were negative at the temperature of 200° C and 300° C under the wet condition respectively. Those values of quartz decreased as the temperature increased from 100° C to 300° C and increased as the temperature increased from 300° C to 600° C. Those values of albite were switched

  5. A new state-of-the-art tool to investigate rock friction under extreme slip velocities and accelerations: SHIVA

    Science.gov (United States)

    Niemeijer, André; di Toro, Giulio; Nielsen, Stefan; Scarlato, Piergiorgio; Romeo, Gianni; di Stefano, Giuseppe; Smith, Steven; di Felice, Fabio; Mariano, Sofia

    2010-05-01

    Despite considerable effort over the past several decades, the mechanics of earthquakes rupture remain largely unknown. In order to complement fault drilling projects and field and seismological observations, recent friction experiments strive to reproduce as closely as possible in-situ (natural) conditions of slip velocity and acceleration on intact and fault rocks. In this contribution, we present a novel state-of-the-art experimental rotary shear apparatus (SHIVA or Slow to HIgh Velocity Apparatus) capable of shearing samples at sliding velocities up to 10 m/s, accelerations of ~ 40 m/s2 and normal stresses up to 50 MPa. In comparison with existing high speed friction machines, this apparatus extends the range of sliding velocities, normal stresses, sample size and, more importantly, accelerations. The apparatus consists of a pair of brushless electric motors (a low velocity motor, 10-6-10-3 m/s, power 5 kW, and a high velocity motor, 10-3 - 10 m/s, power 270 kW), that are connected by a gear system that allows a switch between motors without loss of velocity and force. The motors drive a rotary shaft which clamps ring-shaped samples (diameter 40- 50 mm). On the other side of the rotary shaft, a stationary shaft holds the other half of the sample assembly. The shaft is held stationary by a pair of stainless steel arms, one of which is attached to the side of the concrete-filled base where torque is measured by a tension cell. Axial force (maximum 37 kN) is applied on this side by a piston-cylinder couple with an arm to increase the force. The entire machine measures by 3.5 by 1.2 meters and weighs 3700 kg. We aim to perform experiments on rock samples of a variety of compositions using slip velocities and accelerations that simulate slip velocity functions that occur during earthquakes. In addition, we plan to develop a pore fluid system and a pressure vessel in order to perform experiments that include the physical-chemical processes that occur during slow

  6. High fidelity frictional models for MEMS.

    Energy Technology Data Exchange (ETDEWEB)

    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)

    2004-10-01

    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

  7. Friction stir welding of single crystal aluminium

    DEFF Research Database (Denmark)

    Fonda, Richard Warren; Wert, John A.; Reynolds, A.P.

    2007-01-01

    Friction stir welds were prepared in different orientations in an aluminium single crystal. The welds were quenched to preserve the microstructure surrounding the tool and then electron backscattered diffraction was used to reveal the generation of grain boundaries and the evolution of crystallog......Friction stir welds were prepared in different orientations in an aluminium single crystal. The welds were quenched to preserve the microstructure surrounding the tool and then electron backscattered diffraction was used to reveal the generation of grain boundaries and the evolution...

  8. Ratchet device with broken friction symmetry

    DEFF Research Database (Denmark)

    Norden, Bengt; Zolotaryuk, Yaroslav; Christiansen, Peter Leth

    2002-01-01

    An experimental setup (gadget) has been made for demonstration of a ratchet mechanism induced by broken symmetry of a dependence of dry friction on external forcing. This gadget converts longitudinal oscillating or fluctuating motion into a unidirectional rotation, the direction of which is in ac......An experimental setup (gadget) has been made for demonstration of a ratchet mechanism induced by broken symmetry of a dependence of dry friction on external forcing. This gadget converts longitudinal oscillating or fluctuating motion into a unidirectional rotation, the direction of which...

  9. Analysis of nonlinear channel friction inverse problem

    Institute of Scientific and Technical Information of China (English)

    CHENG Weiping; LIU Guohua

    2007-01-01

    Based on the Backus-Gilbert inverse theory, the singular value decomposition (SVD) for general inverse matrices and the optimization algorithm are used to solve the channel friction inverse problem. The resolution and covari- ance friction inverse model in matrix form is developed to examine the reliability of solutions. Theoretical analyses demonstrate that the convergence rate of the general Newton optimization algorithm is in the second-order. The Wiggins method is also incorporated into the algorithm. Using the method, noise can be suppressed effectively, and the results are close to accurate solutions with proper control parameters. Also, the numerical stability can be improved.

  10. Frictional coupling between sliding and spinning motion

    CERN Document Server

    Farkas, Z; Unger, T; Wolf, D E; Farkas, Zeno; Bartels, Guido; Unger, Tamas; Wolf, Dietrich E.

    2002-01-01

    We show that the friction force and torque, acting at a dry contact of two objects moving and rotating relative to each other, are inherently coupled. As a simple test system, a sliding and spinning disk on a horizontal flat surface is considered. We calculate, and also measure, how the disk is slowing down, and find that it always stops its sliding and spinning motion at the same moment. We discuss the impact of this coupling between friction force and torque on the physics of granular materials.

  11. Monomeric Friction Coefficient of Metalnanodispersible Polymeric Systems

    Directory of Open Access Journals (Sweden)

    B.B. Kolupayev

    2016-12-01

    Full Text Available Influence of a nanodispersible metal excipient in number of 0    5,0 vol.% Cu for the size of a monomeric friction coefficient of polyvinylchloride (PVC systems in temperature range 298  Т  (Tg + 10 K is investigated. It is shown that various types of coordination movements of building blocks are described by a friction coefficient which serves as a measure of influence of external fields and ingredients on viscoelastic behavior of a composite. The analysis of processes of a relaxation on the basis of the theory of flexible chains taking into account power and entropic factors is carried out.

  12. Bifurcations in Systems with Friction : Basic Models and Methods

    NARCIS (Netherlands)

    Ivanov, A. P.

    2009-01-01

    Examples of irregular behavior of dynamical systems with dry friction are discussed. A classification of frictional contacts with respect to their dimensionality, associativity, and the possibility of interruptions is proposed and basic models showing typical features are stated. In particular,

  13. Micromechanisms of friction and wear introduction to relativistic tribology

    CERN Document Server

    Lyubimov, Dmitrij; Pinchuk, Leonid

    2013-01-01

    The modern vision of the micromechanism of friction and wear is explored, from the examination of ideal and real crystal structure and adhesion properties to the dynamics of solid frictional interaction. The fundamental quantum-mechanical and relativity principles of particle interaction are considered as basis of friction micro-process examination. The changes in solid structure originated from the influence of different kinds of force fields are considered. The principal possibility of relativity effect manifestation by friction is explained. The critical state of friction – triboplasma – was studied. Structural peculiarities of triboplasma, the kinetics of its transformation during frictional interaction as well as the influence of plasma and postplasma processes on tribojunction friction characteristics and complex formation by friction were examined. The book addresses to tribology researchers.

  14. Assessing slipperiness in fast-food restaurants in the USA using friction variation, friction level and perception rating.

    Science.gov (United States)

    Chang, Wen-Ruey; Huang, Yueng-Hsiang; Way Li, Kai; Filiaggi, Alfred; Courtney, Theodore K

    2008-05-01

    Although friction variation is speculated to be a significant contributor to slip and fall incidents, it has not been related to a measurement of slipperiness in the literature. This field study investigated the relationship among multiple friction variations, friction levels and the perception ratings of slipperiness in six major working areas of 10 fast-food restaurants in the USA. The mean perception rating score for each working area was correlated with various friction reduction variables across all the restaurants in comparison with its correlation with the mean friction coefficient of each working area. The results indicated that the absolute and relative reductions in friction over the whole working area, among 12 friction reduction variables evaluated, could have a slightly better correlation with the perception rating score (r=0.34 and 0.37, respectively) than the mean friction coefficient of each working area (0.33). However, in friction measurements, more effort and time are needed to quantify friction variations than to obtain the mean friction coefficient. The results of the multiple regression model on the perception rating indicated that adding friction reduction variables into the regression model, in addition to the mean friction coefficient, did not make a significant impact on the outcomes. The results further indicated a statistically significant correlation between the mean friction coefficient and the maximum relative friction reduction over the whole area in each working area across all the restaurants evaluated (r=0.80). Despite a slightly lower correlation with perception rating than the friction variation, the mean friction coefficient of an area is still a reasonably good indicator of slipperiness.

  15. Hip- and knee-strength assessments using a hand-held dynamometer with external belt-fixation are inter-tester reliable

    DEFF Research Database (Denmark)

    Thorborg, Kristian; Bandholm, Thomas; Hölmich, Per

    2013-01-01

    PURPOSE: In football, ice-hockey, and track and field, injuries have been predicted, and hip- and knee-strength deficits quantified using hand-held dynamometry (HHD). However, systematic bias exists when testers of different sex and strength perform the measurements. Belt-fixation of the dynamome......PURPOSE: In football, ice-hockey, and track and field, injuries have been predicted, and hip- and knee-strength deficits quantified using hand-held dynamometry (HHD). However, systematic bias exists when testers of different sex and strength perform the measurements. Belt...

  16. Design of neutral particle incident heating apparatus for large scale helical apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, Osamu; Oka, Yoshihide; Osakabe, Masaki; Takeiri, Yasuhiko; Tsumori, Katsuyoshi; Akiyama, Ryuichi; Asano, Eiji; Kawamoto, Toshikazu; Kuroda, Tsutomu [National Inst. for Fusion Science, Nagoya (Japan)

    1997-02-01

    In the Institute of Nuclear Fusion Science, construction of the large scale helical apparatus has been progressed favorably, and constructions of the heating apparatus as well as of electron resonance apparatus were begun in their orders under predetermined manner since 1994 fiscal year. And, on 1995 fiscal year, construction of neutral particle incident heating apparatus, leading heat apparatus, was begun under 3 years planning. The plasma heating study system adopted the study results developed in this institute through the large scale hydrogen negative ion source and also adopted thereafter development on nuclear fusion study by modifying the original specification set at the beginning of the research plan before 7 years. As a result, system design was changed from initial 125 KeV to 180 KeV in the beam energy and to execute 15 MW incidence using two sets beam lines, to begin its manufacturing. Here is described on its new design with reason of its modifications. (G.K.)

  17. An empirical model for friction in cold forging

    DEFF Research Database (Denmark)

    Bay, Niels; Eriksen, Morten; Tan, Xincai

    2002-01-01

    With a system of simulative tribology tests for cold forging the friction stress for aluminum, steel and stainless steel provided with typical lubricants for cold forging has been determined for varying normal pressure, surface expansion, sliding length and tool/work piece interface temperature...... of normal pressure and tool/work piece interface temperature. The model is verified by process testing measuring friction at varying reductions in cold forward rod extrusion. KEY WORDS: empirical friction model, cold forging, simulative friction tests....

  18. Low-impact friction materials for brake pads

    OpenAIRE

    2016-01-01

    State-of-the-art friction materials for applications in disc brake systems are constituted by composite materials, specifically formulated to ensure proper friction and wear performances, under the sliding contact conditions of braking events. The bases of typical friction compound formulations usually include 10 to 30 different components bonded with a polymeric binder cross-linked in situ. Main requests to be fulfilled during braking are an adequate friction efficiency and enough mechanical...

  19. Development of a spatial filtering apparatus

    Science.gov (United States)

    Wilson, Nicolle

    This thesis contains a discussion of the theoretical background for Fourier spatial filtering and a description of the design and construction of a portable in-class spatial filtering apparatus. A portable, in-class spatial filtering demonstration apparatus was designed and built. This apparatus uses liquid crystal display (LCD) panels from two projectors as the object and filter masks. The blue LCD panel from the first projector serves as the object mask, and the red panel from the second projector serves as the filter mask. The panels were extracted from their projectors and mounted onto aluminum blocks which are held in place by optical component mounts. Images are written to the LCD panels via custom open source software developed for this apparatus which writes independent monochromatic images to the video signal. The software has two monochromatic image windows, basic image manipulation tools, and two video feed input display windows. Two complementary metal-oxide semiconductor (CMOS) sensors are positioned to record the reconstructed image of the object mask and the diffraction pattern created by the object mask. The object and filter mask can be digitally changed and the effects on the filtered image and diffraction pattern can be observed in real-time. The entire apparatus is assembled onto a rolling cart which allows it to be easily taken into classrooms.

  20. Interfacial Friction and Adhesion of Polymer Brushes

    KAUST Repository

    Landherr, Lucas J. T.

    2011-08-02

    A bead-probe lateral force microscopy (LFM) technique is used to characterize the interfacial friction and adhesion properties of polymer brushes. Our measurements attempt to relate the physical structure and chemical characteristics of the brush to their properties as thin-film, tethered lubricants. Brushes are synthesized at several chain lengths and surface coverages from polymer chains of polydimethylsiloxane (PDMS), polystyrene (PS), and a poly(propylene glycol)-poly(ethylene glycol) block copolymer (PPG/PEG). At high surface coverage, PDMS brushes manifest friction coefficients (COFs) that are among the lowest recorded for a dry lubricant film (μ ≈ 0.0024) and close to 1 order of magnitude lower than the COF of a bare silicon surface. Brushes synthesized from higher molar mass chains exhibit higher friction forces than those created using lower molar mass polymers. Increased grafting density of chains in the brush significantly reduces the COF by creating a uniform surface of stretched chains with a decreased surface viscosity. Brushes with lower surface tension and interfacial shear stresses manifest the lowest COF. In particular, PDMS chains exhibit COFs lower than PS by a factor of 3.7 and lower than PPG/PEG by a factor of 4.7. A scaling analysis conducted on the surface coverage (δ) in relation to the fraction (ε) of the friction force developing from adhesion predicts a universal relation ε ∼ δ4/3, which is supported by our experimental data. © 2011 American Chemical Society.

  1. Multiscaling behavior of atomic-scale friction

    Science.gov (United States)

    Jannesar, M.; Jamali, T.; Sadeghi, A.; Movahed, S. M. S.; Fesler, G.; Meyer, E.; Khoshnevisan, B.; Jafari, G. R.

    2017-06-01

    The scaling behavior of friction between rough surfaces is a well-known phenomenon. It might be asked whether such a scaling feature also exists for friction at an atomic scale despite the absence of roughness on atomically flat surfaces. Indeed, other types of fluctuations, e.g., thermal and instrumental fluctuations, become appreciable at this length scale and can lead to scaling behavior of the measured atomic-scale friction. We investigate this using the lateral force exerted on the tip of an atomic force microscope (AFM) when the tip is dragged over the clean NaCl (001) surface in ultra-high vacuum at room temperature. Here the focus is on the fluctuations of the lateral force profile rather than its saw-tooth trend; we first eliminate the trend using the singular value decomposition technique and then explore the scaling behavior of the detrended data, which contains only fluctuations, using the multifractal detrended fluctuation analysis. The results demonstrate a scaling behavior for the friction data ranging from 0.2 to 2 nm with the Hurst exponent H =0.61 ±0.02 at a 1 σ confidence interval. Moreover, the dependence of the generalized Hurst exponent, h (q ) , on the index variable q confirms the multifractal or multiscaling behavior of the nanofriction data. These results prove that fluctuation of nanofriction empirical data has a multifractal behavior which deviates from white noise.

  2. Modelling and Testing of Friction in Forging

    DEFF Research Database (Denmark)

    Bay, Niels

    2007-01-01

    Knowledge about friction is still limited in forging. The theoretical models applied presently for process analysis are not satisfactory compared to the advanced and detailed studies possible to carry out by plastic FEM analyses and more refined models have to be based on experimental testing...

  3. [Penis friction edema: not a venereal disease

    NARCIS (Netherlands)

    Erceg, A.; Verlind, J.; Berretty, P.J.

    2003-01-01

    A 35-year-old man presented with a local swelling of the penis, which increased until the entire penis was thick and swollen. After infectious and obstructive causes had been eliminated, a diagnosis of 'penis friction oedema' was made. The swelling disappeared during several weeks of abstinence from

  4. Friction welding thermal and metallurgical characteristics

    CERN Document Server

    Yilbas, Bekir Sami

    2014-01-01

    This book provides insight into the thermal analysis of friction welding incorporating welding parameters such as external, duration, breaking load, and material properties. The morphological and metallurgical changes associated with the resulting weld sites are analysed using characterization methods such as electron scanning microscope, energy dispersive spectroscopy, X-ray Diffraction, and Nuclear reaction analysis.

  5. Ratchet due to broken friction symmetry

    DEFF Research Database (Denmark)

    Norden, Bengt; Zolotaryuk, Yaroslav; Christiansen, Peter Leth

    2002-01-01

    A ratchet mechanism that occurs due to asymmetric dependence of the friction of a moving system on its velocity or a driving force is reported. For this kind of ratchet, instead of a particle moving in a periodic potential, the dynamics of which have broken space-time symmetry, the system must...

  6. On the superradiance-tidal friction correspondence

    CERN Document Server

    Glampedakis, K; Kennefick, D

    2013-01-01

    Since the work of Hartle in the 1970s, and the subsequent development of the the Membrane Paradigm approach to black hole physics it has been widely accepted that superradiant scattering of gravitational waves bears strong similarities with the phenomenon of ``tidal friction'' (well-known from Newtonian gravity) operating in binary systems of viscous material bodies. In this paper we revisit the superradiance-tidal friction analogy within the context of ultracompact relativistic bodies. We advocate that as long as these bodies have non-zero viscosity they should undergo tidal friction that can be construed as a kind of superradiant scattering from the point of view of the dynamics of an orbiting test-body. In addition we consider the presence of anisotropic matter, which is required for at least some ultracompact bodies, if they are to sustain a radius very close to the gravitational radius. We find that the tidal friction/superradiance output is enhanced with increasing anisotropy and that strongly anisotrop...

  7. Rolling Friction on a Wheeled Laboratory Cart

    Science.gov (United States)

    2012-01-01

    by gravity, and a vehicle (such as a car or bicycle ) accelerating along a level road is driven by a motor or by pedalling. In such cases, static...continuously roll. Consider a cart of mass m that is free rolling up an incline, as sketched in figure 1. The total frictional force f on the cart

  8. Friction Stir Welding of Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    FU Zhi-hong; HE Di-qiu; WANG Hong

    2004-01-01

    Friction stir welding(FSW), a new solid-state welding technology invited in the early 1990s,enables us weld aluminum alloys and titanium alloys etc. The processing of FSW, the microstructure in FSW alloysand the factors influencing weld quality are introduced. The complex factors affecting the properties are researched.

  9. Frictional Dermatosis in a Courier Driver

    Directory of Open Access Journals (Sweden)

    Uwe Wollina

    2017-07-01

    Full Text Available Frictional hypermelanosis is an uncommon finding in Caucasians. We report the unusual case of 56-year-old male courier driver who developed linear and patchy hypermelanosis of the back caused by the driver's seat. Histology has included other pathologies. Treatment of the asymptomatic hyper pigmentation was not warranted.

  10. Validation of measured friction by process tests

    DEFF Research Database (Denmark)

    Eriksen, Morten; Henningsen, Poul; Tan, Xincai;

    The objective of sub-task 3.3 is to evaluate under actual process conditions the friction formulations determined by simulative testing. As regards task 3.3 the following tests have been used according to the original project plan: 1. standard ring test and 2. double cup extrusion test. The task ...

  11. Frictional Torque on a Rotating Disc

    Science.gov (United States)

    Mungan, Carl E.

    2012-01-01

    Resistance to motion often includes a dry frictional term independent of the speed of an object and a fluid drag term varying linearly with speed in the viscous limit. (At higher speeds, quadratic drag can also occur.) Here, measurements are performed for an aluminium disc mounted on bearings that is given an initial twist and allowed to spin…

  12. Friction Force: From Mechanics to Thermodynamics

    Science.gov (United States)

    Ferrari, Christian; Gruber, Christian

    2010-01-01

    We study some mechanical problems in which a friction force is acting on a system. Using the fundamental concepts of state, time evolution and energy conservation, we explain how to extend Newtonian mechanics to thermodynamics. We arrive at the two laws of thermodynamics and then apply them to investigate the time evolution and heat transfer of…

  13. Tribology: Friction, lubrication, and wear technology

    Science.gov (United States)

    Blau, Peter J.

    1993-01-01

    The topics are presented in viewgraph form and include the following: introduction and definitions of terms; friction concepts; lubrication technology concepts; wear technology concepts; and tribological transitions. This document is designed for educators who seek to teach these concepts to their students.

  14. [Penis friction edema: not a venereal disease

    NARCIS (Netherlands)

    Erceg, A.; Verlind, J.; Berretty, P.J.

    2003-01-01

    A 35-year-old man presented with a local swelling of the penis, which increased until the entire penis was thick and swollen. After infectious and obstructive causes had been eliminated, a diagnosis of 'penis friction oedema' was made. The swelling disappeared during several weeks of abstinence from

  15. Fibre Distribution in Friction-spun Yarns

    Institute of Scientific and Technical Information of China (English)

    Eric Oyondi Nganyi; YU Chong-wen

    2006-01-01

    According to the yarn forming characteristics in friction spinning, the arrangement of fed sliver is designed, to get the desired fiber distribution in the resultant yarn. On the base of that, the relation between the theoretical fibre distribution and the actual fibre distribution is analyzed by use of electron microscope.

  16. Simulations of atomic-scale sliding friction

    DEFF Research Database (Denmark)

    Sørensen, Mads Reinholdt; Jacobsen, Karsten Wedel; Stoltze, Per

    1996-01-01

    Simulation studies of atomic-scale sliding friction have been performed for a number of tip-surface and surface-surface contacts consisting of copper atoms. Both geometrically very simple tip-surface structures and more realistic interface necks formed by simulated annealing have been studied. Ki...

  17. 30 CFR 57.19008 - Friction hoist synchronizing mechanisms.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Friction hoist synchronizing mechanisms. 57... MINES Personnel Hoisting Hoists § 57.19008 Friction hoist synchronizing mechanisms. Where creep or slip may alter the effective position of safety devices, friction hoists shall be equipped with...

  18. 30 CFR 56.19008 - Friction hoist synchronizing mechanisms.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Friction hoist synchronizing mechanisms. 56... Personnel Hoisting Hoists § 56.19008 Friction hoist synchronizing mechanisms. Where creep or slip may alter the effective position of safety devices, friction hoists shall be equipped with synchronizing...

  19. 30 CFR 56.19014 - Friction hoist overtravel protection.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Friction hoist overtravel protection. 56.19014 Section 56.19014 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoists § 56.19014 Friction hoist overtravel protection. In a friction hoist installation, tapered...

  20. 30 CFR 57.19014 - Friction hoist overtravel protection.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Friction hoist overtravel protection. 57.19014 Section 57.19014 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Hoisting Hoists § 57.19014 Friction hoist overtravel protection. In a friction hoist installation, tapered...