Science.gov

Sample records for cylindrical grinding operation

  1. Surface waviness resulting from single point diamond dressing in cylindrical grinding

    SciTech Connect

    Redmond, J.; Hinnerichs, T.; Apodaca, E.

    1996-05-01

    This paper describes an experimental investigation of workpiece surface waviness that stems from poor single point diamond wheel dressing procedures in cylindrical grinding. If done improperly, single point dressing can produce a thread on the grinding wheel surface that is then imposed on the workpiece during machining. The circumferential waviness exhibited by the threaded workpiece is similar to that resulting from one per rev vibrations of the grinding wheel. In order to differentiate between these two sources of waviness, a geometrical approach to predicting the circumferential and axial waves produced during grinding is presented. The concepts presented are illustrated through a series of plunge grinding tests incorporating dressing procedures of varying quality. Test results verify that dressing induced circumferential waviness is similar to waviness resulting from one per rev type vibrations of the grinding wheel. The two sources can be distinguished, however, through examination of the workpiece waviness in the axial direction.

  2. Learning Activity Packets for Grinding Machines. Unit III--Cylindrical Grinding.

    ERIC Educational Resources Information Center

    Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This learning activity packet (LAP) is one of three that accompany the curriculum guide on grinding machines. It outlines the study activities and performance tasks for the third unit of this curriculum guide. Its purpose is to aid the student in attaining a working knowledge of this area of training and in achieving a skilled or moderately…

  3. Optimization of the dressing parameters in cylindrical grinding based on a generalized utility function

    NASA Astrophysics Data System (ADS)

    Aleksandrova, Irina

    2016-01-01

    The existing studies, concerning the dressing process, focus on the major influence of the dressing conditions on the grinding response variables. However, the choice of the dressing conditions is often made, based on the experience of the qualified staff or using data from reference books. The optimal dressing parameters, which are only valid for the particular methods and dressing and grinding conditions, are also used. The paper presents a methodology for optimization of the dressing parameters in cylindrical grinding. The generalized utility function has been chosen as an optimization parameter. It is a complex indicator determining the economic, dynamic and manufacturing characteristics of the grinding process. The developed methodology is implemented for the dressing of aluminium oxide grinding wheels by using experimental diamond roller dressers with different grit sizes made of medium- and high-strength synthetic diamonds type ??32 and ??80. To solve the optimization problem, a model of the generalized utility function is created which reflects the complex impact of dressing parameters. The model is built based on the results from the conducted complex study and modeling of the grinding wheel lifetime, cutting ability, production rate and cutting forces during grinding. They are closely related to the dressing conditions (dressing speed ratio, radial in-feed of the diamond roller dresser and dress-out time), the diamond roller dresser grit size/grinding wheel grit size ratio, the type of synthetic diamonds and the direction of dressing. Some dressing parameters are determined for which the generalized utility function has a maximum and which guarantee an optimum combination of the following: the lifetime and cutting ability of the abrasive wheels, the tangential cutting force magnitude and the production rate of the grinding process. The results obtained prove the possibility of control and optimization of grinding by selecting particular dressing

  4. 30 CFR 56.15014 - Eye protection when operating grinding wheels.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Eye protection when operating grinding wheels. 56.15014 Section 56.15014 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... MINES Personal Protection § 56.15014 Eye protection when operating grinding wheels. Face shields...

  5. 30 CFR 56.15014 - Eye protection when operating grinding wheels.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Eye protection when operating grinding wheels. 56.15014 Section 56.15014 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... MINES Personal Protection § 56.15014 Eye protection when operating grinding wheels. Face shields...

  6. 30 CFR 56.15014 - Eye protection when operating grinding wheels.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Eye protection when operating grinding wheels. 56.15014 Section 56.15014 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... MINES Personal Protection § 56.15014 Eye protection when operating grinding wheels. Face shields...

  7. 30 CFR 56.15014 - Eye protection when operating grinding wheels.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Eye protection when operating grinding wheels. 56.15014 Section 56.15014 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... MINES Personal Protection § 56.15014 Eye protection when operating grinding wheels. Face shields...

  8. 30 CFR 56.15014 - Eye protection when operating grinding wheels.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Eye protection when operating grinding wheels. 56.15014 Section 56.15014 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... MINES Personal Protection § 56.15014 Eye protection when operating grinding wheels. Face shields...

  9. Measurements of air concentrations of thorium during grinding and welding operations using thoriated tungsten electrodes

    SciTech Connect

    Crim, E.M.; Bradley, T.D.

    1995-05-01

    An evaluation was performed to determine whether thorium was present in concentrations above the derived air concentration during grinding and welding operations using thoriated tungsten electrodes. A few of the advantages of using thoriated tungsten electrodes in industry include easier arc starting, greater stability, and reduced weld metal contamination. The electrodes used in this evaluation contained 2% thoria (thorium oxide) and were either 2.4 mm or 3.9 mm in diameter. Personal breathing zone and area air samples were collected for the experienced welders participating in this evaluation during grinding operations. The results during the grinding operations for personal and area air samples were generally below the derived air concentration (DAC) for {sup 232}Th for solubility class Y of 0.04 Bq m{sup -3} (1 x 10 {sup -12} {mu}Ci mL{sup -1}) as per 10 CFR 20. The area samples collected during welding operations were below the DAC.

  10. 30 CFR 57.15014 - Eye protection when operating grinding wheels.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Eye protection when operating grinding wheels. 57.15014 Section 57.15014 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... NONMETAL MINES Personal Protection Surface and Underground § 57.15014 Eye protection when...

  11. 30 CFR 57.15014 - Eye protection when operating grinding wheels.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Eye protection when operating grinding wheels. 57.15014 Section 57.15014 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... NONMETAL MINES Personal Protection Surface and Underground § 57.15014 Eye protection when...

  12. 30 CFR 57.15014 - Eye protection when operating grinding wheels.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Eye protection when operating grinding wheels. 57.15014 Section 57.15014 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... NONMETAL MINES Personal Protection Surface and Underground § 57.15014 Eye protection when...

  13. 30 CFR 57.15014 - Eye protection when operating grinding wheels.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Eye protection when operating grinding wheels. 57.15014 Section 57.15014 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... NONMETAL MINES Personal Protection Surface and Underground § 57.15014 Eye protection when...

  14. 30 CFR 57.15014 - Eye protection when operating grinding wheels.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Eye protection when operating grinding wheels. 57.15014 Section 57.15014 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... NONMETAL MINES Personal Protection Surface and Underground § 57.15014 Eye protection when...

  15. Compressible sleeve provides automatic centering for grinding or turning of cylinders

    NASA Technical Reports Server (NTRS)

    Rohrer, J. A.

    1968-01-01

    Elastomeric sleeve supported on a threaded mandrel automatically centers cylindrical castings for grinding or turning. By expanding the diameter of the sleeve with pressure against the ends, the casting becomes rigidly supported and the surfacing operation can be completed.

  16. Tool grinding machine

    DOEpatents

    Dial, Sr., Charles E.

    1980-01-01

    The present invention relates to an improved tool grinding mechanism for grinding single point diamond cutting tools to precise roundness and radius specifications. The present invention utilizes a tool holder which is longitudinally displaced with respect to the remainder of the grinding system due to contact of the tool with the grinding surface with this displacement being monitored so that any variation in the grinding of the cutting surface such as caused by crystal orientation or tool thickness may be compensated for during the grinding operation to assure the attainment of the desired cutting tool face specifications.

  17. Improved tool grinding machine

    DOEpatents

    Dial, C.E. Sr.

    The present invention relates to an improved tool grinding mechanism for grinding single point diamond cutting tools to precise roundness and radius specifications. The present invention utilizes a tool holder which is longitudinally displaced with respect to the remainder of the grinding system due to contact of the tool with the grinding surface with this displacement being monitored so that any variation in the grinding of the cutting surface such as caused by crystal orientation or tool thicknesses may be compensated for during the grinding operation to assure the attainment of the desired cutting tool face specifications.

  18. Effects of High Pressure ORE Grinding on the Efficiency of Flotation Operations

    NASA Astrophysics Data System (ADS)

    Saramak, Daniel; Krawczykowska, Aldona; Młynarczykowska, Anna

    2014-10-01

    This article discusses issues related to the impact of the high pressure comminution process on the efficiency of the copper ore flotation operations. HPGR technology improves the efficiency of mineral resource enrichment through a better liberation of useful components from waste rock as well as more efficient comminution of the material. Research programme included the run of a laboratory flotation process for HPGR crushing products at different levels of operating pressures and moisture content. The test results showed that products of the high-pressure grinding rolls achieved better recoveries in flotation processes and showed a higher grade of useful components in the flotation concentrate, in comparison to the ball mill products. Upgrading curves have also been marked in the following arrangement: the content of useful component in concentrate the floatation recovery. All upgrading curves for HPGR products had a more favourable course in comparison to the curves of conventionally grinded ore. The results also indicate that various values of flotation recoveries have been obtained depending on the machine operating parameters (i.e. the operating pressure), and selected feed properties (moisture).

  19. Force characteristics in continuous path controlled crankpin grinding

    NASA Astrophysics Data System (ADS)

    Zhang, Manchao; Yao, Zhenqiang

    2015-03-01

    Recent research on the grinding force involved in cylindrical plunge grinding has focused mainly on steady-state conditions. Unlike in conventional external cylindrical plunge grinding, the conditions between the grinding wheel and the crankpin change periodically in path controlled grinding because of the eccentricity of the crankpin and the constant rotational speed of the crankshaft. The objective of this study is to investigate the effects of various grinding conditions on the characteristics of the grinding force during continuous path controlled grinding. Path controlled plunge grinding is conducted at a constant rotational speed using a cubic boron nitride (CBN) wheel. The grinding force is determined by measuring the torque. The experimental results show that the force and torque vary sinusoidally during dry grinding and load grinding. The variations in the results reveal that the resultant grinding force and torque decrease with higher grinding speeds and increase with higher peripheral speeds of the pin and higher grinding depths. In path controlled grinding, unlike in conventional external cylindrical plunge grinding, the axial grinding force cannot be disregarded. The speeds and speed ratios of the workpiece and wheel are also analyzed, and the analysis results show that up-grinding and down-grinding occur during the grinding process. This paper proposes a method for describing the force behavior under varied process conditions during continuous path controlled grinding, which provides a beneficial reference for describing the material removal mechanism and for optimizing continuous controlled crankpin grinding.

  20. Operational characteristics and plasma measurements in cylindrical Hall thrusters

    SciTech Connect

    Shirasaki, Atsushi; Tahara, Hirokazu

    2007-04-01

    The cylindrical Hall thruster (CHT) is an attractive approach to achieve a long lifetime thruster operation especially in low power space applications. Because of the larger volume-to-surface ratio than conventional coaxial Hall thrusters, the cylindrical Hall thrusters are characterized by a reduced heating of the thruster parts and potential lower erosion. Existing CHTs can feature a short coaxial channel in order to sustain a high ionization in the thruster discharge. A 5.6 cm diameter cylindrical Hall thruster was developed and operated with and without a short coaxial region of the thruster channel, in the power range of 70-300 W. It is shown that the CHT without coaxial region can operate stable and achieve higher thrust efficiency, 22%-32% more than that with a coaxial region. Plasma probe measurements inside the thruster channel and ion energy measurements in the plasma plume suggest that the ionization/acceleration region in the CHT is located near the anode region where a radial magnetic field is stronger.

  1. Combined Grinding and Drying of Biomass in One Operation Phase I

    SciTech Connect

    Sokhansanj, S

    2008-06-26

    First American Scientific Corporation (FASC) has developed a unique and innovative grinder/dryer called KDS Micronex. The KS (Kinetic Disintegration System) combines two operations of grinding and drying into a single operation which reduces dependence on external heat input. The machine captures the heat of comminution and combines it will centrifugal forces to expedite moisture extraction from wet biomass. Because it uses mechanical forces rather than providing direct heat to perform the drying operation, it is a simpler machine and uses less energy than conventional grinding and drying operations which occur as two separate steps. The entire compact unit can be transported on a flatbed trailer to the site where biomass is available. Hence, the KDS Micronex is a technology that enables inexpensive pretreatment of waste materials and biomass. A well prepared biomass can be used as feed, fuel or fertilizer instead of being discarded. Electricity and chemical feedstock produced from such biomass would displace the use of fossil fuels and no net greenhouse gas emissions would result from such bio-based operations. Organic fertilizers resulting from the KS Micronex grinding/drying process will be pathogen-free unlike raw animal manures. The feasibility tests on KS during Phase I showed that a prototype machine can be developed, field tested and the technology demonstrated for commercial applications. The present KDS machine can remove up to 400 kg/h of water from a wet feed material. Since biomass processors demand a finished product that is only 10% moist and most raw materials like corn stover, bagasse, layer manure, cow dung, and waste wood have moisture contents of the order of 50%, this water removal rate translates to a production rate of roughly half a ton per hour. this is too small for most processors who are unwilling to acquire multiple machines because of the added complexity to the feed and product removal systems. The economics suffer due to small

  2. Performing in-feed type centerless grinding process on a surface grinder

    SciTech Connect

    Xu, W.; Wu, Y.; Sato, T.; Lin, W.

    2011-01-17

    In our previous study, a new centerless grinding method using surface grinder was proposed. In this method, centerless grinding operations are performed by installing a compact centerless grinding unit, consisting mainly of an ultrasonic elliptic-vibration shoe, a blade and their respective holders, on the worktable of a surface grinder. During grinding, the cylindrical workpiece is held on the ultrasonic shoe and the blade, and its rotational motion is controlled by the elliptic motion of the shoe end-face. An actual unit had been produced and its performance in tangential-feed type centerless grinding using a surface grinder had been confirmed in the previous workd. In this paper, the performance of the grinding unit in in-feed centerless grinding operation was confirmed, and the effects of the main process parameter, i.e., eccentric angle, on the workpiece roundness was investigated experimentally. The obtained results showed that: (1) the centerless grinding unit performed well in in-feed type centerless grinding; (2) the eccentric angle affects roundness significantly, and its optimal angle is 6 deg.; (3) the workpiece roundness can be further improved by varying the eccentric angle during grinding, and the final roundness reached 0.65 {mu}m after grinding as the eccentric angle varied from 9 deg. to 6 deg. and to 3 deg.

  3. A Guide for Developing Standard Operating Job Procedures for the Screening & Grinding Process Wastewater Treatment Facility. SOJP No. 1.

    ERIC Educational Resources Information Center

    Deal, Gerald A.; Montgomery, James A.

    This guide describes standard operating job procedures for the screening and grinding process of wastewater treatment facilities. The objective of this process is the removal of coarse materials from the raw waste stream for the protection of subsequent equipment and processes. The guide gives step-by-step instructions for safety inspection,…

  4. Forecasting of operational indicators of grinding tools with the controlled form and orientation of abrasive grains

    NASA Astrophysics Data System (ADS)

    Korotkov, V. A.; Minkin, E. M.

    2015-09-01

    rational angle of grain orientation for cutting disc are in range Θ=65°÷75°. The joint analysis of dependences of front angles and tension in grains from factors of their form and orientation allows the prediction of operating characteristics of grinding tools at the design stage for specific tasks and processing conditions.

  5. Crush Grinding

    SciTech Connect

    T. Q. Nguyen

    2005-04-01

    Crush Grinding is a special process used at the Kansas City Plant to finish stem sections of reservoir products. In this process, a precise profile of the desired product is formed on a tungsten carbide roll. This roll slowly transfers a mirror image of the profile onto the grinding surface of a wheel. The transfer rate of the profile is between 0.001 and 0.010 inches per minute. Crush grinding is desirable since it provides consistent surface finishes and thin walls at a high production rate. In addition, it generates very sharp fillet radii. However, crush grinding is a complex process since many variables affect the final product. Therefore, the process requires more attention and knowledge beyond basic metal removal practices. While the Kansas City Plant began using these machines in 1995, a formal study regarding crush grinding has not been conducted there. In addition, very little literature is available in the grinding industry regarding this process. As a result, new engineers at the Kansas City Plant must learn the process through trial and error. The purpose of this document is to address this literature deficit while specifically promoting a better understanding of the stem crush grinding process at the Kansas City Plant.

  6. Innovative grinding wheel design for cost-effective machining of advanced ceramics

    SciTech Connect

    Licht, R.H.; Kuo, P.; Liu, S.; Murphy, D.; Picone, J.W.; Ramanath, S.

    2000-05-01

    This Final Report covers the Phase II Innovative Grinding Wheel (IGW) program in which Norton Company successfully developed a novel grinding wheel for cost-effective cylindrical grinding of advanced ceramics. In 1995, Norton Company successfully completed the 16-month Phase I technical effort to define requirements, design, develop, and evaluate a next-generation grinding wheel for cost-effective cylindrical grinding of advanced ceramics using small prototype wheels. The Phase II program was initiated to scale-up the new superabrasive wheel specification to larger diameters, 305-mm to 406-mm, required for most production grinding of cylindrical ceramic parts, and to perform in-house and independent validation grinding tests.

  7. The method of assessment of the grinding wheel cutting ability in the plunge grinding

    NASA Astrophysics Data System (ADS)

    Nadolny, Krzysztof

    2012-09-01

    This article presents the method of comparative assessment of the grinding wheel cutting ability in the plunge grinding kinematics. A new method has been developed to facilitate multicriterial assessment of the working conditions of the abrasive grains and the bond bridges, as well as the wear mechanisms of the GWAS, which occur during the grinding process, with simultaneous limitation of the workshop tests range. The work hereby describes the methodology of assessment of the grinding wheel cutting ability in a short grinding test that lasts for 3 seconds, for example, with a specially shaped grinding wheel, in plunge grinding. The grinding wheel macrogeometry modification applied in the developed method consists in forming a cone or a few zones of various diameters on its surface in the dressing cut. It presents an exemplary application of two variants of the method in the internal cylindrical plunge grinding, in 100Cr6 steel. Grinding wheels with microcrystalline corundum grains and ceramic bond underwent assessment. Analysis of the registered machining results showed greater efficacy of the method of cutting using a grinding wheel with zones of various diameters. The method allows for comparative tests upon different grinding wheels, with various grinding parameters and different machined materials.

  8. Grinding away

    SciTech Connect

    Korz, T.

    2009-03-15

    Coal preparation in gasification plants is all too often neglected. The coal gasification industry has experienced enormous growth over the last few years and consequently the demand of coal grinding and drying has also increased. The design and development of coal mills has taken great strides since the first coal grinding plant was delivered to an IGCC power plant in Buggenum, Netherlands. The article describes a typical flow sheet for a coal gasification plant with a possibility of feeding the mill with different types of materials besides coal. 5 figs.

  9. Standard Operating Procedure for the Grinding and Extraction of Lead in Paint using Nitric Acid and a Rotor/Stator System Powered by a High Speed Motor

    EPA Science Inventory

    This Standard Operating Procedure (SOP) describes a new, rapid, and relatively inexpensive one step procedure which grinds the paint samples removed from the substrate and simultaneously quantitatively extracts the Pb from the paint in only one step in preparation for quantitativ...

  10. Grinding assembly, grinding apparatus, weld joint defect repair system, and methods

    DOEpatents

    Larsen, Eric D.; Watkins, Arthur D.; Bitsoi, Rodney J.; Pace, David P.

    2005-09-27

    A grinding assembly for grinding a weld joint of a workpiece includes a grinder apparatus, a grinder apparatus includes a grinding wheel configured to grind the weld joint, a member configured to receive the grinding wheel, the member being configured to be removably attached to the grinder apparatus, and a sensor assembly configured to detect a contact between the grinding wheel and the workpiece. The grinding assembly also includes a processing circuitry in communication with the grinder apparatus and configured to control operations of the grinder apparatus, the processing circuitry configured to receive weld defect information of the weld joint from an inspection assembly to create a contour grinding profile to grind the weld joint in a predetermined shape based on the received weld defect information, and a manipulator having an end configured to carry the grinder apparatus, the manipulator further configured to operate in multiple dimensions.

  11. Apparatus for and method of operating a cylindrical pulsed induction mass launcher

    DOEpatents

    Cowan, Jr., Maynard; Duggin, Billy W.; Widner, Melvin M.

    1992-01-01

    An electromagnetic cylindrical projectile mass launcher and a method of operation is provided which includes a cylindrical projectile having a conducting armature, a cylindrical barrel in which the armature is received, a plurality of electromagnetic drive coil stages, a plurality of pulse energy sources, and a pulsed power arrangement for generating magnetic pulses forming a pulsed magnetic wave along the length of the launcher barrel. The pulsed magnetic wave provides a propelling force on the projectile along the drive coil. The pulsed magnetic wave of the drive coil stages is advanced along the armature faster than the projectile to thereby generate an induced current wave in the armature. The pulsed generation of the magnetic wave minimizes electromagnetic heating of the projectile and provides for smooth acceleration of the projectile through the barrel of the launcher.

  12. Apparatus for and method of operating a cylindrical pulsed induction mass launcher

    DOEpatents

    Cowan, M. Jr.; Duggin, B.W.; Widner, M.M.

    1992-06-30

    An electromagnetic cylindrical projectile mass launcher and a method of operation is provided which includes a cylindrical projectile having a conducting armature, a cylindrical barrel in which the armature is received, a plurality of electromagnetic drive coil stages, a plurality of pulse energy sources, and a pulsed power arrangement for generating magnetic pulses forming a pulsed magnetic wave along the length of the launcher barrel. The pulsed magnetic wave provides a propelling force on the projectile along the drive coil. The pulsed magnetic wave of the drive coil stages is advanced along the armature faster than the projectile to thereby generate an induced current wave in the armature. The pulsed generation of the magnetic wave minimizes electromagnetic heating of the projectile and provides for smooth acceleration of the projectile through the barrel of the launcher. 2 figs.

  13. Method for grinding precision components

    DOEpatents

    Ramanath, Srinivasan; Kuo, Shih Yee; Williston, William H.; Buljan, Sergej-Tomislav

    2000-01-01

    A method for precision cylindrical grinding of hard brittle materials, such as ceramics or glass and composites comprising ceramics or glass, provides material removal rates as high as 19-380 cm.sup.3 /min/cm. The abrasive tools used in the method comprise a strong, light weight wheel core bonded to a continuous rim of abrasive segments containing superabrasive grain in a dense metal bond matrix.

  14. Modelling of dynamic contact length in rail grinding process

    NASA Astrophysics Data System (ADS)

    Zhi, Shaodan; Li, Jianyong; Zarembski, A. M.

    2014-09-01

    Rails endure frequent dynamic loads from the passing trains for supporting trains and guiding wheels. The accumulated stress concentrations will cause the plastic deformation of rail towards generating corrugations, contact fatigue cracks and also other defects, resulting in more dangerous status even the derailment risks. So the rail grinding technology has been invented with rotating grinding stones pressed on the rail with defects removal. Such rail grinding works are directed by experiences rather than scientifically guidance, lacking of flexible and scientific operating methods. With grinding control unit holding the grinding stones, the rail grinding process has the characteristics not only the surface grinding but also the running railway vehicles. First of all, it's important to analyze the contact length between the grinding stone and the rail, because the contact length is a critical parameter to measure the grinding capabilities of stones. Moreover, it's needed to build up models of railway vehicle unit bonded with the grinding stone to represent the rail grinding car. Therefore the theoretical model for contact length is developed based on the geometrical analysis. And the calculating models are improved considering the grinding car's dynamic behaviors during the grinding process. Eventually, results are obtained based on the models by taking both the operation parameters and the structure parameters into the calculation, which are suitable for revealing the process of rail grinding by combining the grinding mechanism and the railway vehicle systems.

  15. Visual enhancements in pick-and-place tasks - Human operators controlling a simulated cylindrical manipulator

    NASA Technical Reports Server (NTRS)

    Kim, Won S.; Tendick, Frank; Stark, Lawrence W.

    1987-01-01

    A teleoperation simulator has been constructed with vector display system, joysticks, and a simulated cylindrical manipulator, in order to quantitatively evaluate various display conditions. The first of two experiments thus conducted investigated the effects of perspective parameter variations on human operators' pick-and-place performance, using a monoscopic perspective display. The second experiment involved visual enhancements of the monoscopic perspective display, by adding a grid and reference lines, by comparison with visual enhancements of a stereoscopic display; results indicate that stereoscopy generally permits superior pick-and-place performance, but that monoscopy nevertheless allows equivalent performance when defined with appropriate perspective parameter values and adequate visual enhancements.

  16. Visual enhancements in pick-and-place tasks: Human operators controlling a simulated cylindrical manipulator

    NASA Technical Reports Server (NTRS)

    Kim, Won S.; Tendick, Frank; Stark, Lawrence

    1989-01-01

    A teleoperation simulator was constructed with vector display system, joysticks, and a simulated cylindrical manipulator, in order to quantitatively evaluate various display conditions. The first of two experiments conducted investigated the effects of perspective parameter variations on human operators' pick-and-place performance, using a monoscopic perspective display. The second experiment involved visual enhancements of the monoscopic perspective display, by adding a grid and reference lines, by comparison with visual enhancements of a stereoscopic display; results indicate that stereoscopy generally permits superior pick-and-place performance, but that monoscopy nevertheless allows equivalent performance when defined with appropriate perspective parameter values and adequate visual enhancements.

  17. Operation characteristics of cylindrical miniature grooved heat pipe using aqueous CuO nanofluids

    SciTech Connect

    Wang, Guo-Shan; Song, Bin; Liu, Zhen-Hua

    2010-11-15

    An experimental study was performed to investigate the operation characteristics of a cylindrical miniature grooved heat pipe using aqueous CuO nanofluid as the working fluid at some steady cooling conditions. The experiments were carried out under both the steady operation process and the unsteady startup process. The experiment results show that substituting the nanofluid for water as the working fluid can apparently improve the thermal performance of the heat pipe for steady operation. The total heat resistance and the maximum heat removal capacity of the heat pipe using nanofluids can maximally reduce by 50% and increase by 40% compared with that of the heat pipe using water, respectively. For unsteady startup process, substituting the nanofluid for water as the working fluid, cannot only improve the thermal performance, but also reduce significantly the startup time. (author)

  18. Wire Electrical Discharge Truing of Metal Bond Diamond Grinding Wheels

    SciTech Connect

    McSpadden, SB

    2002-01-24

    Cylindrical wire EDM profile truing of the metal bond diamond wheel for precision form grinding of ceramics is presented in this report. First a corrosion-resistant, precise spindle with the high-electrical current capability for wire EDM truing of grinding wheel was fabricated. An arc profile was adopted in order to determine form tolerances capabilities of this process. Results show the wire EDM process can generate {micro}m-scale precision form on the diamond wheel efficiently. The wheel, after truing, was used to grind silicon nitride. Grinding forces, surface finish of ground components, and wheel wear were measured. The EDM trued wheel showed a reduction in grinding force from that of the stick dressed wheel. Surface finishes between the two truing methods were similar. In the beginning of the grinding, significant wheel wear rate was identified. The subsequent wheel wear rate stabilized and became considerably lower.

  19. Grinding Parts For Automatic Welding

    NASA Technical Reports Server (NTRS)

    Burley, Richard K.; Hoult, William S.

    1989-01-01

    Rollers guide grinding tool along prospective welding path. Skatelike fixture holds rotary grinder or file for machining large-diameter rings or ring segments in preparation for welding. Operator grasps handles to push rolling fixture along part. Rollers maintain precise dimensional relationship so grinding wheel cuts precise depth. Fixture-mounted grinder machines surface to quality sufficient for automatic welding; manual welding with attendant variations and distortion not necessary. Developed to enable automatic welding of parts, manual welding of which resulted in weld bead permeated with microscopic fissures.

  20. Conduit grinding apparatus

    DOEpatents

    Nachbar, Henry D.; Korytkowski, Alfred S.

    1991-01-01

    A grinding apparatus for grinding the interior portion of a valve stem receiving area of a valve. The apparatus comprises a faceplate, a plurality of cams mounted to an interior face of the faceplate, a locking bolt to lock the faceplate at a predetermined position on the valve, a movable grinder and a guide tube for positioning an optical viewer proximate the area to be grinded. The apparatus can either be rotated about the valve for grinding an area of the inner diameter of a valve stem receiving area or locked at a predetermined position to grind a specific point in the receiving area.

  1. The Effect of Cutting Speed in Metallic Glass Grinding

    SciTech Connect

    Serbest, Erdinc; Bakkal, Mustafa; Karipcin, Ilker; Derin, Bora

    2011-01-17

    In this paper, the effects of the cutting speed in metallic glass grinding were investigated in dry conditions. The results showed that grinding forces decrease as grinding energy increase with the increasing cutting speeds. The present investigations on ground surface and grinding chips morphologies -shows that material removal and surface formation of the BMG are mainly due to the ductile chip deformation and ploughing as well as brittle fracture of some particles from the edges of the tracks. The roughness values obtained with the Cubic Boron Nitride wheels are acceptable for the grinding operation.

  2. Development of massproductive ultraprecision grinding technology for brittle material devices

    SciTech Connect

    Kanai, A.; Miyashita, M.; Daito, M.

    1996-12-31

    Experimental results from an ultaprecision, centerless grinding system are reported. The system is designed for ductile mode grinding of brittle material devices on a mass production scale. A postprocess work diameter measuring stand was used with the high stiffness grinding machine.Size error correction was shown to be practically applicable as a mass production ultraprecision ferrule grinding technology. The key items were determined to be: (1) force-operated positioning servo system of slide on plain bearing guideways, (2) measurement of relative motion between grinding and regulating wheels with differential linear encoder, (3) application of linear encoder stability, and (4) application of microtruing technology to wheels.

  3. Design and Operating Characteristics of High-Speed, Small-Bore Cylindrical-Roller Bearings

    NASA Technical Reports Server (NTRS)

    Pinel, Stanley, I.; Signer, Hans R.; Zaretsky, Erwin V.

    2000-01-01

    The computer program SHABERTH was used to analyze 35-mm-bore cylindrical roller bearings designed and manufactured for high-speed turbomachinery applications. Parametric tests of the bearings were conducted on a high-speed, high-temperature bearing tester and the results were compared with the computer predictions. Bearings with a channeled inner ring were lubricated through the inner ring, while bearings with a channeled outer ring were lubricated with oil jets. Tests were run with and without outer-ring cooling. The predicted bearing life decreased with increasing speed because of increased contact stresses caused by centrifugal load. Lower temperatures, less roller skidding, and lower power losses were obtained with channeled inner rings. Power losses calculated by the SHABERTH computer program correlated reasonably well with the test results. The Parker formula for XCAV (used in SHABERTH as a measure of oil volume in the bearing cavity) needed to be adjusted to reflect the prevailing operating conditions. The XCAV formula will need to be further refined to reflect roller bearing lubrication, ring design, cage design, and location of the cage-controlling land.

  4. Grinding Away Microfissures

    NASA Technical Reports Server (NTRS)

    Booth, Gary N.; Malinzak, R. Michael

    1990-01-01

    Treatment similar to dental polishing used to remove microfissures from metal parts without reworking adjacent surfaces. Any variety of abrasive tips attached to small motor used to grind spot treated. Configuration of grinding head must be compatible with configurations of motor and workpiece. Devised to eliminate spurious marks on welded parts.

  5. Grinding Wheel System

    DOEpatents

    Malkin, Stephen; Gao, Robert; Guo, Changsheng; Varghese, Biju; Pathare, Sumukh

    2006-01-10

    A grinding wheel system includes a grinding wheel with at least one embedded sensor. The system also includes an adapter disk containing electronics that process signals produced by each embedded sensor and that transmits sensor information to a data processing platform for further processing of the transmitted information.

  6. Grinding Wheel System

    DOEpatents

    Malkin, Stephen; Gao, Robert; Guo, Changsheng; Varghese, Biju; Pathare, Sumukh

    2003-08-05

    A grinding wheel system includes a grinding wheel with at least one embedded sensor. The system also includes an adapter disk containing electronics that process signals produced by each embedded sensor and that transmits sensor information to a data processing platform for further processing of the transmitted information.

  7. Use of in-process EDM truing to generate complex contours on metal-bond, superabrasive grinding wheels for precision grinding structural ceramics

    SciTech Connect

    Piscotty, M. A., LLNL

    1997-08-01

    This paper presents recent work performed at Lawrence Livermore National Laboratory to develop cost-effective, versatile and robust manufacturing methods for grinding precision features in structural ceramics using metal-bond, superabrasive grinding wheels. The developed processes include utilizing specialized, on-machine hardware to generate precision profiles onto grinding wheels using electrical-discharge machining (EDM) and a contoured rotating electrode. The production grinding processes are described, which were developed and used to grind various precision details into a host of structural ceramics such as Al{sub 2}O{sub 3}, Si{sub 3}N{sub 4}, and BeO. The methodologies, hardware and results of both creep-feed and cylindrical grinding are described. A discussion of imparted grinding damage and wheel wear is also presented.

  8. Crystalline silica dust and respirable particulate matter during indoor concrete grinding - wet grinding and ventilated grinding compared with uncontrolled conventional grinding.

    PubMed

    Akbar-Khanzadeh, Farhang; Milz, Sheryl; Ames, April; Susi, Pamela P; Bisesi, Michael; Khuder, Sadik A; Akbar-Khanzadeh, Mahboubeh

    2007-10-01

    The effectiveness of wet grinding (wet dust reduction method) and ventilated grinding (local exhaust ventilation method, LEV) in reducing the levels of respirable crystalline silica dust (quartz) and respirable suspended particulate matter (RSP) were compared with that of uncontrolled (no dust reduction method) conventional grinding. A field laboratory was set up to simulate concrete surface grinding using hand-held angle grinders in an enclosed workplace. A total of 34 personal samples (16 pairs side-by-side and 2 singles) and 5 background air samples were collected during 18 concrete grinding sessions ranging from 15-93 min. General ventilation had no statistically significant effect on operator's exposure to dust. Overall, the arithmetic mean concentrations of respirable crystalline silica dust and RSP in personal air samples during: (i) five sessions of uncontrolled conventional grinding were respectively 61.7 and 611 mg/m(3) (ii) seven sessions of wet grinding were 0.896 and 11.9 mg/m(3) and (iii) six sessions of LEV grinding were 0.155 and 1.99 mg/m(3). Uncontrolled conventional grinding generated relatively high levels of respirable silica dust and proportionally high levels of RSP. Wet grinding was effective in reducing the geometric mean concentrations of respirable silica dust 98.2% and RSP 97.6%. LEV grinding was even more effective and reduced the geometric mean concentrations of respirable silica dust 99.7% and RSP 99.6%. Nevertheless, the average level of respirable silica dust (i) during wet grinding was 0.959 mg/m(3) (38 times the American Conference of Governmental Industrial Hygienists [ACGIH] threshold limit value [TLV] of 0.025 mg/m(3)) and (ii) during LEV grinding was 0.155 mg/m(3) (6 times the ACGIH TLV). Further studies are needed to examine the effectiveness of a greater variety of models, types, and sizes of grinders on different types of cement in different positions and also to test the simulated field lab experimentation in the field

  9. Bearing restoration by grinding

    NASA Technical Reports Server (NTRS)

    Hanau, H.; Parker, R. J.; Zaretsky, E. V.; Chen, S. M.; Bull, H. L.

    1976-01-01

    A joint program was undertaken by the NASA Lewis Research Center and the Army Aviation Systems Command to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. No bearing failures occurred related to the restoration by grinding process. The risk and cost of a bearing restoration by grinding programs was analyzed. A microeconomic impact analysis was performed.

  10. Classifier mills for coal grinding and drying

    SciTech Connect

    Galk, J.; Peukert, W.

    1995-12-31

    This report presents a special air classifier mill for coal grinding. Air classifier mills use the two fundamental process steps grinding and classifying in one machine. An essential advantage is the independent operation of grinding rotor speed and classifier rotor speed. This offers good control of the produced particle size distribution and great flexibility in process control. Using an air classifier mill for grinding coal followed by direct injection into the firing chamber allows for good control of burnout. Another advantage is that drying of coal can take place as a parallel step by heating process air passing through the classifier mill. In this report an air classifier mill, some typical process data, possible throughput, and an industrial application are shown.

  11. Vitreous bond CBN high speed and high material removal rate grinding of ceramics

    SciTech Connect

    Shih, A.J.; Grant, M.B.; Yonushonis, T.M.; Morris, T.O.; McSpadden, S.B.

    1998-08-01

    High speed (up to 127 m/s) and high material removal rate (up to 10 mm{sup 3}/s/mm) grinding experiments using a vitreous bond CBN wheel were conducted to investigate the effects of material removal rate, wheel speed, dwell time and truing speed ratio on cylindrical grinding of silicon nitride and zirconia. Experimental results show that the high grinding wheel surface speed can reduce the effective chip thickness, lower grinding forces, enable high material removal rate grinding and achieve a higher G-ratio. The radial feed rate was increased to as high as 0.34 {micro}m/s for zirconia and 0.25 {micro}m/s for silicon nitride grinding to explore the advantage of using high wheel speed for cost-effective high material removal rate grinding of ceramics.

  12. Ultra-fine grinding of coal

    SciTech Connect

    Wang Shoulu; Wang Xinguo; Gao Ying

    1997-12-31

    Clean coal is known by its low ash content. Most coals contain a large amount of ash, some of which are finely distributed in the coal matrix. With the conventional cleaning process, such ash can not be removed efficiently. From existing coal preparation plants, much middling and high-ash slime come out as by-products and are used only as inferior fuel. Beijing Graduate School, China University of Mining and Technology, has developed a process for deep-cleaning of coal. This process includes ultra-fine grinding of coal to liberate the locked ash minerals followed by efficient separation with selective coagulation-flotation. With this process, concentrate can be extracted from inferior coal or ultra-clean coal can be obtained from conventional concentrate. Tumbling and vibrating ball mills are conventional for general grinding. However, for ultra-fine grinding they are inefficient and consume much more power. This paper gives some aspects of an ultra-fine grinding mill developed by Beijing Graduate School. The Ultra-Fine Grinding Mill is a JMI series wet grinding mill, and consists of a static horizontal closed tube with a rotor inside. The rotor assembly includes: a horizontal shaft, two vaned disks being fixed apart at the shaft, and longitudinal bar deflectors fixed across the disks. Sufficient clearance is allowed between the disk and end plates of the tube and between the disk rim and tube wall. This configuration enables free passage of grinding medium and pulp within the mill. While the mill is in operation, four principal movements of grinding medium and pulp are created: inward radially by deflectors, oppositely axial by vanes, tangential by rotation, and vibrating due to vortices behind the deflectors.

  13. A quadrupole ion trap with cylindrical geometry operated in the mass-selective instability mode.

    PubMed

    Wells, J M; Badman, E R; Cooks, R G

    1998-02-01

    A cylindrical geometry ion trap is used to record mass spectra in the mass-selective instability mode. The geometry of the cylindrical ion trap has been optimized to maximize the quadrupole field component relative to the higher-order field content through field calculations using the Poisson/Superfish code and through experimental variation of the electrode structure. The results correspond well with predictions of the calculations. The trap has been used to record mass spectra with better than unit mass resolution, high sensitivity, and a mass/charge range of ∼600 Th. Multistage (MS(3)) experiments have been performed, and the Mathieu stability region has been experimentally mapped. The performance of this device compares satisfactorily with that of the hyperbolic ion trap. PMID:21644742

  14. 36. INTERIOR VIEW, NORTON GRINDER, TYPES USED TO GRIND ROUGH ...

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

    36. INTERIOR VIEW, NORTON GRINDER, TYPE-S USED TO GRIND ROUGH EDGES OFF THE FORGED TOOLS; NOTE OPERATOR IS FINISH GRINDING BLADE END OF A POST HOLE DIGGER AND TAMPING BAR - Warwood Tool Company, Foot of Nineteenth Street, Wheeling, Ohio County, WV

  15. Grinding kinetics and equilibrium states

    NASA Technical Reports Server (NTRS)

    Opoczky, L.; Farnady, F.

    1984-01-01

    The temporary and permanent equilibrium occurring during the initial stage of cement grinding does not indicate the end of comminution, but rather an increased energy consumption during grinding. The constant dynamic equilibrium occurs after a long grinding period indicating the end of comminution for a given particle size. Grinding equilibrium curves can be constructed to show the stages of comminution and agglomeration for certain particle sizes.

  16. Electro-chemical grinding

    NASA Technical Reports Server (NTRS)

    Feagans, P. L.

    1972-01-01

    Electro-chemical grinding technique has rotation speed control, constant feed rates, and contour control. Hypersonic engine parts of nickel alloys can be almost 100% machined, keeping tool pressure at virtual zero. Technique eliminates galling and permits constant surface finish and burr-free interrupted cutting.

  17. Grinding Wheel Profile

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This graphic dubbed by engineers as the 'Grinding Wheel Profile' is the detective's tool used by the Opportunity team to help them understand one of the processes that formed the interior of a rock called 'McKittrick.' Scientists are looking for clues as to how layers, grains and minerals helped create this rock, and the engineers who built the rock abrasion tool (RAT) wanted to ensure that their instrument's handiwork did not get confused with natural processes.

    In the original microscopic image underlaying the graphics, engineers and scientists noticed 'layers' or 'scratches' on the spherical object nicknamed 'blueberry' in the lower right part of the image. The designers of the rock abrasion tool noticed that the arc length and width of the scratches were similar to the shape and size of the rock abrasion tool's grinding wheel, which is made out of a pad of diamond teeth.

    The scrapes on the bottom right blueberry appear to be caused by the fact that the berry got dislodged slightly and its surface was scraped with the grinding pad. In this image, the largest yellow circle is the overall diameter of the hole ground by the rock abrasion tool and the largest yellow rectangular shape is the area of the grinding wheel bit. The smaller yellow semi-circle is the path that the center of the grinding tool follows. The orange arrow arcing around the solid yellow circle (center of grinding tool) indicates the direction that the grinding tool spins around its own center at 3,000 revolutions per minute. The tool simultaneously spins in an orbit around the center of the hole, indicated by the larger orange arrow to the left.

    The grinding tool is 22 millimeters (0.9 inches) in length and the actual grinding surface, which consists of the diamond pad, is 1.5 millimeters (0.06 inches) in length, indicated by the two smaller rectangles. You can see that the smaller bottom rectangle fits exactly the width of the scrape marks.

    The grooves on the blueberry are also the

  18. The influence of grinding oil viscosity on grinding heat and burn damage in creep-feed grinding{copyright}

    SciTech Connect

    Zhen-Change Liu; Abe, Satoshi; Noda, Masahiro

    1995-08-01

    Grinding oils are widely used in precision grinding, such as tool grinding, thread grinding and gear grinding, during which processes grinding burn is the most prevalent damage affecting the integrity of ground surface. This paper discusses the influence of oil viscosity on grinding heat and burn damage in creep-feed-grinding. Experimental results indicated that, under lighter grinding conditions, the effects of oil viscosity was not observed, but under heavy grinding conditions grinding burn occurred when using low viscosity oil. When the viscosity of the oil was increased, grinding heat and burn damage tended to be reduced. As the viscosity was increased to a certain level, grinding burn reduction, by further increasing the viscosity, became less while other problems such as much higher oil pump noise and reduced oil flow occurred. It is clear that a viscosity limit exists for given grinding conditions. 5 refs., 4 figs., 3 tabs.

  19. Medical insurance claims and surveillance for occupational disease: analysis of respiratory, cardiac, and cancer outcomes in auto industry tool grinding operations.

    PubMed

    Park, R M

    2001-04-01

    To evaluate medical insurance claims for chronic disease investigation, claims from eight automotive machining plants (1984 to 1993) were linked with work histories (1967 to 1993), and associations with respiratory, cardiac, and cancer conditions were investigated, in a case-control design analyzed with logistic regression. The primary focus was tool grinding, but other important processes examined were metal-working, welding, forging, heat treat, engine testing, and diverse-skilled trades work. Considerable variability in claim-derived incidence rates across plants was not explained by age or known exposure differences. Asthma incidence increased in tool grinding (at mean cumulative duration: odds ratio [OR], 3.0; 95% confidence interval [CI], 0.90 to 10.0), as did non-ischemic heart disease (cardiomyopathy, cor pulmonale, rheumatic heart disease, or hypertension; OR, 3.1; 95% CI, 1.26 to 7.6). These trends appeared in models with deficits (OR < 1.0) for those ever exposed to tool grinding because of exposure-response miss-specification, demographic confounding, or removal of high-risk workers from the exposed group. The apparent cancer rates identified from claims greatly exceeded the expected rates from a cancer registry, suggesting that diagnostic, "rule-out," and surveillance functions were contributing. This study supports the epidemiologic use of medical insurance records in surveillance and, possibly, etiologic investigation and identifies issues requiring special attention or resolution. PMID:11322094

  20. Grinding machine: friend or foe.

    PubMed

    Adigun, I A; Kuranga, S A; Abdulrahman, L O

    2002-01-01

    Few cases of traumatic loses of the external genitalia have been reported in this part of the world. In a developing country like ours, grinding machines are commonly being used by the people for domestic purposes. Children in their mid fifteens are usually employed to man and operate the machine without proper training and apprenticeship. Many of them have fallen victims of various genito-urinary injuries from grinding machine. Treating a child for complete traumatic loss of penis is rare and challenging any where in the world. A 12 years old boy presented to the emergency unit of our hospital with penile amputation 18 hours after the injury was sustained. A penile reconstruction of corporal cavernosa phalloplasty was used. This method of reconstruction may be used by clinician in our sub-region where other treatment modalities such as replantation by microvascular surgery, use of free radial fore-arm flap or sex reassignment to the female gender may not be feasible or acceptable. PMID:12665282

  1. A Tough Grind

    NASA Technical Reports Server (NTRS)

    2004-01-01

    NASA's Mars Exploration Rover Spirit took the four images that make up this mosaic with its microscopic imager on sol 82. The mosaic reveals the drilled surface of the target called 'New York' on the rock dubbed 'Mazatzal.' The rock abrasion tool ground for 3 hours and 45 minutes to create this 3.8 millimeter-deep (0.15 inch) hole. The exposed area is 4.5 centimeters (1.8 inches) in diameter.

    Mazatzal was an interesting rock to grind because it has a lighter tone than the previously ground rocks 'Adirondack' and 'Humphrey,' and because it looks different from its surrounding environment. Scientists hypothesized that Mazatzal's surface might be covered with a rind of weathered material. They drilled through this very top layer to reveal the underlying rock.

    Because Mazatzal's surface was not even, the left half of the rock was penetrated more deeply than the right. As can be seen in this image, the right, darker portion of the rock is still covered by the rind material. Spirit completed a second grind at this location at a different angle to remove the remaining veneer from the right side and create an even deeper hole. Images of this second grind will be sent back to Earth in the next sol or two.

    After the Final Grind The image was acquired on sol 85 after the rover drilled into New York a second time with its rock abrasion tool. Remnants of the dark grey coating that covers Mazatzal's interior can be seen at the right side of the hole. The crack in the rock may have once contained fluids out of which minerals precipitated. Each image making up this mosaic is 3 centimeters (1.2 inches) across.

  2. High-speed, low-damage grinding of advanced ceramics Phase 1. Final report

    SciTech Connect

    Kovach, J.A.; Malkin, S.

    1995-03-01

    In manufacture of structural ceramic components, grinding costs can comprise up to 80% of the entire manufacturing cost. Most of these costs arise from the conventional multi-step grinding process with numerous grinding wheels and additional capital equipment, perishable dressing tools, and labor. In an attempt to reduce structural ceramic grinding costs, a feasibility investigation was undertaken to develop a single step, roughing-finishing process suitable for producing high-quality silicon nitride ceramic parts at high material removal rates at lower cost than traditional, multi-stage grinding. This feasibility study employed combined use of laboratory grinding tests, mathematical grinding models, and characterization of resultant material surface condition. More specifically, this Phase 1 final report provides a technical overview of High-Speed, Low-Damage (HSLD) ceramic grinding and the conditions necessary to achieve the small grain depths of cut necessary for low damage grinding while operating at relatively high material removal rates. Particular issues addressed include determining effects of wheel speed and material removal rate on resulting mode of material removal (ductile or brittle fracture), limiting grinding forces, calculation of approximate grinding zone temperatures developed during HSLD grinding, and developing the experimental systems necessary for determining HSLD grinding energy partition relationships. In addition, practical considerations for production utilization of the HSLD process are also discussed.

  3. 2. DETAIL VIEW OF JOURNAL LATHE, AXLE FINISHING AREA. Grinding ...

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

    2. DETAIL VIEW OF JOURNAL LATHE, AXLE FINISHING AREA. Grinding bearing diameters on locomotive axle. Norton grinder, 1942 (dated). Melvin Grassmeyer, operator. - Juniata Shops, Machine Shop No. 1, East of Fourth Avenue at Third Street, Altoona, Blair County, PA

  4. 3. DETAIL VIEW OF JOURNAL LATHE, AXLE FINISHING AREA. Grinding ...

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

    3. DETAIL VIEW OF JOURNAL LATHE, AXLE FINISHING AREA. Grinding bearing diameters on locomotive axle. Norton grinder, 1942 (dated). Melvin Grassmeyer, operator. - Juniata Shops, Machine Shop No. 1, East of Fourth Avenue at Third Street, Altoona, Blair County, PA

  5. Grinding Inside A Toroidal Cavity

    NASA Technical Reports Server (NTRS)

    Mayer, Walter; Adams, James F.; Burley, Richard K.

    1987-01-01

    Weld lines ground smooth within about 0.001 in. Grinding tool for smoothing longitudinal weld lines inside toroidal cavity includes curved tunnel jig to guide grinding "mouse" along weld line. Curvature of tunnel jig matched to shape of toroid so grinding ball in mouse follows circular arc of correct radius as mouse is pushed along tunnel. Tool enables precise control of grindout shape, yet easy to use.

  6. Cylindrical Scanner

    Energy Science and Technology Software Center (ESTSC)

    1999-04-29

    The CS system is designed to provide a very fast imaging system in order to search for weapons on persons in an airport environment. The Cylindrical Scanner moves a vertical transceiver array rapidly around a person standing stationary. The software can be segmented in to three specific tasks. The first task is data acquisition and scanner control. At the operator's request, this task commands the scanner to move and the radar transceiver array to sendmore » data to the computer system in a known and well-ordered manner. The array is moved over the complete aperture in 10 to 12 seconds. At the completion of the array movement the second software task automatically reconstructs the high-resolution image from the radar data utilizing the integrated DSP boards. The third task displays the resulting images, as they become available, to the computer screen for user review and analysis.« less

  7. Cylindrical Scanner

    SciTech Connect

    Hall, Thomas E.

    1999-04-29

    The CS system is designed to provide a very fast imaging system in order to search for weapons on persons in an airport environment. The Cylindrical Scanner moves a vertical transceiver array rapidly around a person standing stationary. The software can be segmented in to three specific tasks. The first task is data acquisition and scanner control. At the operator's request, this task commands the scanner to move and the radar transceiver array to send data to the computer system in a known and well-ordered manner. The array is moved over the complete aperture in 10 to 12 seconds. At the completion of the array movement the second software task automatically reconstructs the high-resolution image from the radar data utilizing the integrated DSP boards. The third task displays the resulting images, as they become available, to the computer screen for user review and analysis.

  8. Cryogenic Grinding: a Physical Technique to Retain Volatile Content in Natural Products

    NASA Astrophysics Data System (ADS)

    Saxena, Rohit; Soni, Aditi; Saxna, S. N.; Rathore, S. S.; Barnwal, P.

    Cryogenics is the study of the production of very low temperature (below -150°C, -238°F or 123K) and the behavior of materials at those temperatures. Similarly, cryogenic grinding is a term supported by the act of grinding a thing at very low temperature. This technique is generally used to grind the material, which contains heat labile constituents viz- volatile oils in seed spices. Due to high fat content in spices, heat is generated, while energy is used to fracture a particle into a smaller size in conventional grinding process. During the normal grinding process, this generated heat causes temperature rise of grinder upto 950C. The increased temperature is responsible for a loss of volatile content in the tune of about 30% and also produces dark colour powder. Generally, continuous operation is not possible in normal grinding process due to melting of fat and sticking of powder on the grinding surface. The loss of volatile content can be significantly reduced by cryogenic grinding technique using liquid nitrogen or liquid carbon dioxide that provides the refrigeration needed to pre-cool the spices and maintain the desired low temperature by absorbing the heat generated during the grinding operation. The extremely low temperature during grinder condenses the volatile matter and retains their presence in spices. The application of cryogenic technology for grinding of spices has been scientifically proved to be a suitable technique with negligible loss of volatile content and improved colour of oil and grinding operation of seeds.

  9. McCarter superfinish grinding for silicon -- an update.

    SciTech Connect

    Anthony, F.; Khounsary, A.; McCarter, D.; Krasnicki, F.; Tangedahl, M.

    2000-11-03

    A grinding technique, referred to as the McCarter Superfinish, for grinding large size optical components is discussed and certain surface characterization information about flatness and the relative magnitude of the subsurface damage in silicon substrates is reported. The flatness measurements were obtained with a Zygo surface analyzer, and the substrate damage measurements were made by x-ray diffraction and acid etching. Results indicate excellent control of flatness and fine surface finish. X-ray measurements show that the diamond wheels with small particle sizes used in the final phases of the grinding operation renders surfaces with relatively small subsurface damage.

  10. Innovative grinding wheel design for cost-effective machining of advanced ceramics. Phase I, final report

    SciTech Connect

    Licht, R.H.; Ramanath, S.; Simpson, M.; Lilley, E.

    1996-02-01

    Norton Company successfully completed the 16-month Phase I technical effort to define requirements, design, develop, and evaluate a next-generation grinding wheel for cost-effective cylindrical grinding of advanced ceramics. This program was a cooperative effort involving three Norton groups representing a superabrasive grinding wheel manufacturer, a diamond film manufacturing division and a ceramic research center. The program was divided into two technical tasks, Task 1, Analysis of Required Grinding Wheel Characteristics, and Task 2, Design and Prototype Development. In Task 1 we performed a parallel path approach with Superabrasive metal-bond development and the higher technical risk, CVD diamond wheel development. For the Superabrasive approach, Task 1 included bond wear and strength tests to engineer bond-wear characteristics. This task culminated in a small-wheel screening test plunge grinding sialon disks. In Task 2, an improved Superabrasive metal-bond specification for low-cost machining of ceramics in external cylindrical grinding mode was identified. The experimental wheel successfully ground three types of advanced ceramics without the need for wheel dressing. The spindle power consumed by this wheel during test grinding of NC-520 sialon is as much as to 30% lower compared to a standard resin bonded wheel with 100 diamond concentration. The wheel wear with this improved metal bond was an order of magnitude lower than the resin-bonded wheel, which would significantly reduce ceramic grinding costs through fewer wheel changes for retruing and replacements. Evaluation of ceramic specimens from both Tasks 1 and 2 tests for all three ceramic materials did not show evidence of unusual grinding damage. The novel CVD-diamond-wheel approach was incorporated in this program as part of Task 1. The important factors affecting the grinding performance of diamond wheels made by CVD coating preforms were determined.

  11. CNC grinding of valve housing piston holes

    SciTech Connect

    Ashbaugh, F.A.

    1991-11-01

    Grinding has traditionally been used for machining operations requiring close dimensional tolerances and better surface finishes than can be obtained from other metal removal techniques. Using a grinding process for the last metal removal operation, the close tolerances and surface finishes can be easily held while eliminating the adverse conditions from the current metal removal processes. Pre-machined test parts were sent to a machine tool supplier to have the critical inside features of a typical piston bore finish machined using an internal CNC grinder equipped with high-frequency spindles. The piston bore and sealing angle were ground using a standard 120-grit silicon carbide wheel. The wafer step was machined using a solid carbide tool designed and built at Allied-Signal Inc., Kansas City Division (KCD). Six consecutive parts were machined for evaluation. The repeatability on all six parts was within print requirements. The inside corner radii was less than 0.002 in. and the surface finish was 8.2 arithmetical average or better as defined by ANSI B46.1, Surface Texture. Machining parts by this grinding process would eliminate bellmouth, chatter, waviness, and traveler polishing operations. It would produce a superior surface finish, small inside radii, and small easily removable burrs. It would also hold tolerances closer and significantly reduce scrap, rework, rejects, and deviations. 1 fig.

  12. Grinding process monitoring based on electromechanical impedance measurements

    NASA Astrophysics Data System (ADS)

    Marchi, Marcelo; Guimarães Baptista, Fabricio; de Aguiar, Paulo Roberto; Bianchi, Eduardo Carlos

    2015-04-01

    Grinding is considered one of the last processes in precision parts manufacturing, which makes it indispensable to have a reliable monitoring system to evaluate workpiece surface integrity. This paper proposes the use of the electromechanical impedance (EMI) method to monitor the surface grinding operation in real time, particularly the surface integrity of the ground workpiece. The EMI method stands out for its simplicity and for using low-cost components such as PZT (lead zirconate titanate) piezoelectric transducers. In order to assess the feasibility of applying the EMI method to the grinding process, experimental tests were performed on a surface grinder using a CBN grinding wheel and a SAE 1020 steel workpiece, with PZT transducers mounted on the workpiece and its holder. During the grinding process, the electrical impedance of the transducers was measured and damage indices conventionally used in the EMI method were calculated and compared with workpiece wear, indicating the surface condition of the workpiece. The experimental results indicate that the EMI method can be an efficient and cost-effective alternative for monitoring precision workpieces during the surface grinding process.

  13. Cylindrical wormholes

    SciTech Connect

    Bronnikov, K. A.; Lemos, Jose P. S.

    2009-05-15

    It is shown that the existence of static, cylindrically symmetric wormholes does not require violation of the weak or null energy conditions near the throat, and cylindrically symmetric wormhole geometries can appear with less exotic sources than wormholes whose throats have a spherical topology. Examples of exact wormhole solutions are given with scalar, spinor and electromagnetic fields as sources, and these fields are not necessarily phantom. In particular, there are wormhole solutions for a massless, minimally coupled scalar field in the presence of a negative cosmological constant, and for an azimuthal Maxwell electromagnetic field. All these solutions are not asymptotically flat. A no-go theorem is proved, according to which a flat (or string) asymptotic behavior on both sides of a cylindrical wormhole throat is impossible if the energy density of matter is everywhere nonnegative.

  14. Machining Thin-Walled Cylindrical Parts

    NASA Technical Reports Server (NTRS)

    Cimbak, Joe; Spagnolo, Jim; Kraus, Dan

    1988-01-01

    Cylindrical walls only few thousandths of inch thick machined accurately and without tears or punctures with aid of beryllium copper mandrel. Chilled so it contracts, then inserted in cylinder. As comes to room temperature, mandrel expands and fits snugly inside cylinder. Will not allow part to slide and provides solid backup to prevent deflection when part machined by grinding wheel. When machining finished, cylinder-and-mandrel assembly inserted in dry ice, mandrel contracts and removed from part.

  15. Influence parameters of impact grinding mills

    NASA Technical Reports Server (NTRS)

    Hoeffl, K.; Husemann, K.; Goldacker, H.

    1984-01-01

    Significant parameters for impact grinding mills were investigated. Final particle size was used to evaluate grinding results. Adjustment of the parameters toward increased charge load results in improved efficiency; however, it was not possible to define a single, unified set to optimum grinding conditions.

  16. Ceramic-bonded abrasive grinding tools

    DOEpatents

    Holcombe, Jr., Cressie E.; Gorin, Andrew H.; Seals, Roland D.

    1994-01-01

    Abrasive grains such as boron carbide, silicon carbide, alumina, diamond, cubic boron nitride, and mullite are combined with a cement primarily comprised of zinc oxide and a reactive liquid setting agent and solidified into abrasive grinding tools. Such grinding tools are particularly suitable for grinding and polishing stone, such as marble and granite.

  17. Ceramic-bonded abrasive grinding tools

    DOEpatents

    Holcombe, C.E. Jr.; Gorin, A.H.; Seals, R.D.

    1994-11-22

    Abrasive grains such as boron carbide, silicon carbide, alumina, diamond, cubic boron nitride, and mullite are combined with a cement primarily comprised of zinc oxide and a reactive liquid setting agent and solidified into abrasive grinding tools. Such grinding tools are particularly suitable for grinding and polishing stone, such as marble and granite.

  18. "Grinding" cavities in polyurethane foam

    NASA Technical Reports Server (NTRS)

    Brower, J. R.; Davey, R. E.; Dixon, W. F.; Robb, P. H.; Zebus, P. P.

    1980-01-01

    Grinding tool installed on conventional milling machine cuts precise cavities in foam blocks. Method is well suited for prototype or midsize production runs and can be adapted to computer control for mass production. Method saves time and materials compared to bonding or hot wire techniques.

  19. Ultrasonic precision optical grinding technology

    NASA Astrophysics Data System (ADS)

    Cahill, Michael J.; Bechtold, Michael J.; Fess, Edward; Wolfs, Frank L.; Bechtold, Rob

    2015-10-01

    As optical geometries become more precise and complex and a wider range of materials are used, the processes used for manufacturing become more critical. As the preparatory stage for polishing, this is especially true for grinding. Slow processing speeds, accelerated tool wear, and poor surface quality are often detriments in manufacturing glass and hard ceramics. The quality of the ground surface greatly influences the polishing process and the resulting finished product. Through extensive research and development, OptiPro Systems has introduced an ultrasonic assisted grinding technology, OptiSonic, which has numerous advantages over traditional grinding processes. OptiSonic utilizes a custom tool holder designed to produce oscillations in line with the rotating spindle. A newly developed software package called IntelliSonic is integral to this platform. IntelliSonic automatically characterizes the tool and continuously optimizes the output frequency for optimal cutting while in contact with the part. This helps maintain a highly consistent process under changing load conditions for a more accurate surface. Utilizing a wide variety of instruments, test have proven to show a reduction in tool wear and increase in surface quality while allowing processing speeds to be increased. OptiSonic has proven to be an enabling technology to overcome the difficulties seen in grinding of glass and hard optical ceramics. OptiSonic has demonstrated numerous advantages over the standard CNC grinding process. Advantages are evident in reduced tool wear, better surface quality, and reduced cycle times due to increased feed rates. These benefits can be seen over numerous applications within the precision optics industry.

  20. Critical parameters for grinding large sapphire window panels

    NASA Astrophysics Data System (ADS)

    Bashe, Joseph R.; Dempsey, Gene; Akwani, Ikerionwu A.; Jacoby, Keith T.; Hibbard, Douglas L.

    2007-04-01

    Advances in optical manufacturing and testing technologies for sapphire material are required to support the increasing use of large-aperture sapphire panels as windscreens for various electro-optical system applications. Single surface grinding is a crucial process step in both the figuring and finishing of optical components. Improper grinding can make subsequent polishing operations more difficult and time consuming. Poor grinding can also lead to the introduction of surface stress and sub-surface damage which can affect critical opto-mechanical performance characteristics such as strength and durability. Initial efforts have been completed at Exotic Electro-Optics under the funding of the Office of Naval Research and the Air Force Research Laboratory to investigate a number of process enhancements in the grinding of a-plane sapphire panels. The information gained from this study will ultimately provide a better understanding of the overall manufacturing process leading to optimized process time and cost. EEO has completed two sets of twelve-run Plackett-Burman designs of experiment (DOE) to study the effects of fundamental grinding parameters on sapphire panel surfaces. The relative importance of specific process parameters on window characteristics including surface roughness, stress, sub-surface damage are reported.

  1. Achieving process control through improved grinding techniques for ferrite materials

    SciTech Connect

    Bruce, J.

    1995-09-01

    In manufacturing soft ferrite materials the particle size of the raw material has a significant impact on the reactivity of calcination. The control of particle size distribution and final formulation at wet milling after calcining impacts the reactivity during sintering and the magnetic properties of the final product. This paper will deal with steps taken to improve process control during the grinding operations of raw material and calcine in soft ferrite production. Equipment modifications as well as changes to the grinding and material handling techniques will be included. All examples of process control and improvements will be supported by data.

  2. Fused silica fine grinding with low roughness

    NASA Astrophysics Data System (ADS)

    Dai, Lei; Gu, Yongqiang; Wu, Di

    2014-08-01

    Lithography-optics is one of the most complex optical systems. The fine grinding process is the most important step before polishing. Roughness and sub-surface damage (SSD) are essential outputs of fine grinding. We demonstrate the method that use fix abrasive cup tool with CNC grinding machine to complete the fine grinding process, even instead of lapping process. And experiment sample roughness can reach 23.40nm rms and Ra 18.554nm. The SSD estimate is about 2 μm which is also smaller than commercial lapping process. The fine grinding output can satisfy the lithography optic fabrication demands and efficiently reduce the polishing time.

  3. Characterization of grinding wheels: An annotated Bibliography. Final report

    SciTech Connect

    McClung, R.W.

    1995-12-01

    The characteristics of grinding wheels, after both fabrication and periods of operation, have a significant effect on the processed surface and the mechanical properties of advanced ceramics. An extensive literature survey and review has been conducted to determine and catalogue the various characterization methods that have been investigated and reported. Although many of the references have addressed the grinding of metals, the historical and technical merit justify their inclusion in this bibliography. For convenience, the references have been subdivided into nine subheadings: Nondestructive examination; elasticity and stiffness; wheel hardness; topography and profilometry; observation of texture of wheel surfaces wheel wear; in process monitoring of grinding, acoustic emission, other; characteristics of ground surfaces; and miscellaneous.

  4. Microfabricated cylindrical ion trap

    DOEpatents

    Blain, Matthew G.

    2005-03-22

    A microscale cylindrical ion trap, having an inner radius of order one micron, can be fabricated using surface micromachining techniques and materials known to the integrated circuits manufacturing and microelectromechanical systems industries. Micromachining methods enable batch fabrication, reduced manufacturing costs, dimensional and positional precision, and monolithic integration of massive arrays of ion traps with microscale ion generation and detection devices. Massive arraying enables the microscale cylindrical ion trap to retain the resolution, sensitivity, and mass range advantages necessary for high chemical selectivity. The microscale CIT has a reduced ion mean free path, allowing operation at higher pressures with less expensive and less bulky vacuum pumping system, and with lower battery power than conventional- and miniature-sized ion traps. The reduced electrode voltage enables integration of the microscale cylindrical ion trap with on-chip integrated circuit-based rf operation and detection electronics (i.e., cell phone electronics). Therefore, the full performance advantages of microscale cylindrical ion traps can be realized in truly field portable, handheld microanalysis systems.

  5. Thermally induced grinding damage in cast equiaxed nickel-based superalloys

    SciTech Connect

    Kovach, J.A.

    1986-01-01

    The overall objective of this program was to increase the understanding and productivity of conventional grinding operations utilized in the finishing of cast equiaxed nickel-based superalloy components. To achieve this overall goal a four phase approach was employed. Initially, a grinding energy partition relationship for conventional grinding of superalloys was developed. Secondly, the mechanisms and conditions that influence superalloy microcracking during abusive grinding were determined. Third, building on the above relationships, a means of readily predicting the onset of grinding damage in cast Rene-77 and B-1900 superalloys was established. Finally, the results were implemented in production surface grinding operations to increase superalloy grinding quality and productivity. Finite element analyses were utilized to determine the superalloy grinding zone temperatures and residual stresses. The results indicated that Rene-77 microcracks are not formed by the residual stresses alone. The effects of constitutional liquation or weakening of the grain boundaries due to rapid heating to such temperatures were shown to be significant. It was then demonstrated that workplace damage would occur when the combined conducted and convected heat flux exceeded a critical limit.

  6. Optimization of Cylindrical Hall Thrusters

    SciTech Connect

    Yevgeny Raitses, Artem Smirnov, Erik Granstedt, and Nathaniel J. Fi

    2007-07-24

    The cylindrical Hall thruster features high ionization efficiency, quiet operation, and ion acceleration in a large volume-to-surface ratio channel with performance comparable with the state-of-the-art annular Hall thrusters. These characteristics were demonstrated in low and medium power ranges. Optimization of miniaturized cylindrical thrusters led to performance improvements in the 50-200W input power range, including plume narrowing, increased thruster efficiency, reliable discharge initiation, and stable operation. __________________________________________________

  7. Optimization of Cylindrical Hall Thrusters

    SciTech Connect

    Yevgeny Raitses, Artem Smirnov, Erik Granstedt, and Nathaniel J. Fisch

    2007-11-27

    The cylindrical Hall thruster features high ionization efficiency, quiet operation, and ion acceleration in a large volume-to-surface ratio channel with performance comparable with the state-of-the-art annular Hall thrusters. These characteristics were demonstrated in low and medium power ranges. Optimization of miniaturized cylindrical thrusters led to performance improvements in the 50-200W input power range, including plume narrowing, increased thruster efficiency, reliable discharge initiation, and stable operation.

  8. Comparison of High-Speed Operating Characteristics of Size 215 Cylindrical-Roller Bearings as Determined in Turbojet Engine and in Laboratory Test Rig

    NASA Technical Reports Server (NTRS)

    Macks, E Fred; Nemeth, Zolton N

    1952-01-01

    A comparison of the operating characteristics of 75-millimeter-bore (size 215) cylindrical-roller one-piece inner-race-riding cage-type bearings was made by means of a laboratory test rig and a turbojet engine. Cooling correlation parameters were determined by means of dimensional analysis, and the generalized results for both the inner- and the outer-race bearing operating temperatures are computed for the laboratory test rig and the turbojet engine. A method is given that enables the designer to predict the inner- and outer-race turbine roller-bearing temperatures from single curves, regardless of variations in speed, load, oil flow, oil inlet temperature, oil inlet viscosity, oil-jet diameter, or any combination of these parameters.

  9. Correlation between mass transfer coefficient kLa and relevant operating parameters in cylindrical disposable shaken bioreactors on a bench-to-pilot scale

    PubMed Central

    2013-01-01

    Background Among disposable bioreactor systems, cylindrical orbitally shaken bioreactors show important advantages. They provide a well-defined hydrodynamic flow combined with excellent mixing and oxygen transfer for mammalian and plant cell cultivations. Since there is no known universal correlation between the volumetric mass transfer coefficient for oxygen kLa and relevant operating parameters in such bioreactor systems, the aim of this current study is to experimentally determine a universal kLa correlation. Results A Respiration Activity Monitoring System (RAMOS) was used to measure kLa values in cylindrical disposable shaken bioreactors and Buckingham’s π-Theorem was applied to define a dimensionless equation for kLa. In this way, a scale- and volume-independent kLa correlation was developed and validated in bioreactors with volumes from 2 L to 200 L. The final correlation was used to calculate cultivation parameters at different scales to allow a sufficient oxygen supply of tobacco BY-2 cell suspension cultures. Conclusion The resulting equation can be universally applied to calculate the mass transfer coefficient for any of seven relevant cultivation parameters such as the reactor diameter, the shaking frequency, the filling volume, the viscosity, the oxygen diffusion coefficient, the gravitational acceleration or the shaking diameter within an accuracy range of +/− 30%. To our knowledge, this is the first kLa correlation that has been defined and validated for the cited bioreactor system on a bench-to-pilot scale. PMID:24289110

  10. Ultraprecision, high stiffness CNC grinding machines for ductile mode grinding of brittle materials

    NASA Astrophysics Data System (ADS)

    McKeown, Patrick A.; Carlisle, Keith; Shore, Paul; Read, R. F.

    1990-10-01

    Under certain controlled conditions it is now possible to machine brittle materials such as glasses and ceramics using single or multi-point diamond tools (grinding), so that material is removed by plastic flow, leaving crack-free surfaces. This process is called 'shear' or 'ductile' mode grinding. It represents a major breakthrough in modern manufacturing engineering since it promises to enable: - complex optical components, both transmission and reflecting to be generated by advanced CNC machines with very little (or even zero) subsequent polishing. - complex shaped components such as turbine blades, nozzle guide vanes, etc. to be finish machined after near net shape forming, to high precision in advanced ceramics such as silicon nitride, without inducing micro-cracking and thus lowering ultimate rupture strength and fatigue life. Ductile mode "damage free" grinding occurs when the volume of materials stressed by each grit of the grinding wheel is small enough to yield rather than exhibit brittle fracture, i.e. cracking. In practice, this means maintaining the undeformed chip thickness to below the ductile-brittle transition value; this varies from material to material but is generally in the order of 0.1 pm or 100 nm, (hence the term "nanogrinding" is sometimes used) . Thus the critical factors for operating successfully in the ductile regime are machine system accuracy and dynamic stiffness between each grit and the workpiece. In detail this means: (i) High precision 'truing' of the diamond grits, together with dressing of the wheel bond to ensure adequate ' openness'; (ii) Design and build of the grinding wheel spindle with very high dynamic stiffness; error motions, radial and axial, must be considerably less than 100 nfl. (iii) Design and build of the workpiece carriage motion system with very high dynamic stiffness; error motions, linear or rotary, must be well within 100 nm. (iv) Smooth, rumble-free, high-stiffness servo-drives controlling the motions

  11. Grinding arrangement for ball nose milling cutters

    NASA Technical Reports Server (NTRS)

    Burch, C. F. (Inventor)

    1974-01-01

    A grinding arrangement for spiral fluted ball nose end mills and like tools includes a tool holder for positioning the tool relative to a grinding wheel. The tool is mounted in a spindle within the tool holder for rotation about its centerline and the tool holder is pivotably mounted for angular movement about an axis which intersects that centerline. A follower arm of a cam follower secured to the spindle cooperates with a specially shaped cam to provide rotation of the tool during the angular movement of the tool holder during the grinding cycle, by an amount determined by the cam profile. In this way the surface of the cutting edge in contact with the grinding wheel is maintained at the same height on the grinding wheel throughout the angular movement of the tool holder during the grinding cycle.

  12. Changeing of fly ash leachability after grinding

    NASA Astrophysics Data System (ADS)

    Lakatos, J.; Szabo, R.; Racz, A.; Banhidi, O.; Mucsi, G.

    2016-04-01

    Effect of grinding on the reactivity of fly ash used for geopolymer production was tested. Extraction technique using different alkaline and acidic solutions were used for detect the change of the solubility of elements due to the physical and mechano-chemical transformation of minerals in function of grinding time. Both the extraction with alkaline and acidic solution have detected improvement in solubility in function of grinding time. The enhancement in alkaline solution was approx. 100% in case of Si and Al. The acidic medium able to dissolve the fly ash higher manner than the alkaline, therefore the effect of grinding was found less pronounced.

  13. Autogenous grinding for bath scraps recycling

    SciTech Connect

    Pinoncely, A.; Podda, P.

    1996-10-01

    In the early 80`s, FCB designed an original process for the recycling of bath scraps in Aluminum smelters, using a single stage fully air-swept autogenous mill. Since then, the 9 industrial references confirmed and even exceeded the expectation in terms of dust-free and easy to run operation, high recovery ratio of bath among the metallic scraps, and low maintenance cost. Problems encountered on conventional processes belong to the old days, and new projects tend to give an increasing importance to classification and storage of crushed products, autogenous grinding being already recognized as the most suitable, simple and reliable process route. The present paper describes this original process and draws up the overall performances of ten years of experience.

  14. Study on numerical simulation of the dynamic impact effect for optical glass grinding with single grit

    NASA Astrophysics Data System (ADS)

    Chen, Jiang; Zhang, Feihu; Hang, Zhao; Yong, Zhang; Su, Jianbo

    It studies failure mechanism of optical glass with impact stress from grit, according to the dynamic impact effect in the process of optical glass grinding with single grit. With the distribution regularity of crack which from the grit dynamic impact, it established mathematical model of cylindrical stress wave which coaxial with wavefront. Analyzing and establishing the control equations for cylindrical stress wave, using finite-difference technique to simulate the dynamic impact effect for optical glass grinding with single grit and adopting Zwas numerical methods with source term hyperbolic curve partial differential equations to analysis and study the dissemination rule, diffusion rule and change rule, the simulation analysis shows that in the dissemination process of grit impact wave , wavefront occurred diffusion and there are tensile stress generated as well as oscillation.

  15. APPARATUS FOR GRINDING SPHERICAL BODIES

    DOEpatents

    Burch, R.F. Jr.

    1963-09-24

    A relatively inexpensive device is described for grinding rough ceramic bodies into accurate spherical shapes using a conventional drill press and a belt sander. A horizontal disk with an abrasive-surfaced recess in its lower face is mounted eccentrically on a vertical shaft which is forced downward against a stop by a spring. Bodies to be ground are placed in the recess and are subjected to the abrasive action of the belt sander as the disk is rotated by the drill press. (AEC)

  16. 'Diamond Jenness': Before the Grind

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This microscopic imager mosaic of the rock called 'Diamond Jenness' was snapped on sol 177 before NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool, or 'Rat.'

    Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer. On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

    The image mosaic is about 6 centimeters (2.4 inches) across.

  17. 'Diamond Jenness': After the Grind

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This microscopic imager mosaic taken by NASA's Mars Exploration Rover Opportunity shows the rock dubbed 'Diamond Jenness.' It was taken on sol 177 (July 23, 2004) after the rover first ground into the rock with its rock abrasion tool, or 'Rat.' The rover later ground into the rock a second time. A sliced spherule, or 'blueberry,' is visible in the upper left corner of the hole.

    Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.

    On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

    The image mosaic is about 6 centimeters (2.4 inches) across.

  18. 'Diamond Jenness': A Tough Grind

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This microscopic imager mosaic of the target area called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.

    Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.

    On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

    The image mosaic is about 6 centimeters (2.4 inches) across.

  19. Lathe converted for grinding aspheric surfaces

    NASA Technical Reports Server (NTRS)

    Larmer, J. W.; Levinsohn, M.; Mc Craw, D.; Pessagno, E. H.; Taub, F. J.

    1964-01-01

    A standard overarm tracing lathe converted by the addition of an independently driven diamond grinding wheel is used for grinding aspheric surfaces. The motion of the wheel is controlled by the lathe air tracer following the template which produces the desired aspheric profile.

  20. Precision grinding process development for brittle materials

    SciTech Connect

    Blaedel, K L; Davis, P J; Piscotty, M A

    1999-04-01

    High performance, brittle materials are the materials of choice for many of today's engineering applications. This paper describes three separate precision grinding processes developed at Lawrence Liver-more National Laboratory to machine precision ceramic components. Included in the discussion of the precision processes is a variety of grinding wheel dressing, truing and profiling techniques.

  1. Precision diamond grinding of ceramics and glass

    SciTech Connect

    Smith, S.; Paul, H.; Scattergood, R.O.

    1988-12-01

    A new research initiative will be undertaken to investigate the effect of machine parameters and material properties on precision diamond grinding of ceramics and glass. The critical grinding depth to initiate the plastic flow-to-brittle fracture regime will be directly measured using plunge-grind tests. This information will be correlated with machine parameters such as wheel bonding and diamond grain size. Multiaxis grinding tests will then be made to provide data more closely coupled with production technology. One important aspect of the material property studies involves measuring fracture toughness at the very short crack sizes commensurate with grinding damage. Short crack toughness value`s can be much less than the long-crack toughness values measured in conventional fracture tests.

  2. Evaluation of Recycle Grinding Performance in Flour Milling

    NASA Astrophysics Data System (ADS)

    Mazlina Mustapa Kamal, Siti; Webb, Colin

    A typical flour milling process is a very linear operation that is almost entirely void of recycled streams where separate fractions from each operation go ahead as new streams to the next operation. In some cases, there are opportunities for combining some streams, for recycling particles that have been insufficiently broken to go back to the same roller mill. This study introduces this recycle concept in flour milling process at second break system. The recycle grinding assessment was made using a Satake STR-100 test roller mill. The recycle process was started after the second break system and the number of recycle grinding was up to 7 regrinds. The particle size distribution and ash analysis were produced to describe the behaviour of the recycle grinding performance. The material release was sifted on a range of sieves and the ash content was analysed using a laboratory furnace. The performance for each recycle stage was investigated. It was determined that it is possible for some coarse particles that contain only bran to keep being recycled in the recycle circuit. A purging operation was recommended to be included in the recycle system, to separate the unwanted particles.

  3. Machining and grinding: High rate deformation in practice

    SciTech Connect

    Follansbee, P.S.

    1993-04-01

    Machining and grinding are well-established material-working operations involving highly non-uniform deformation and failure processes. A typical machining operation is characterized by uncertain boundary conditions (e.g.,surface interactions), three-dimensional stress states, large strains, high strain rates, non-uniform temperatures, highly localized deformations, and failure by both nominally ductile and brittle mechanisms. While machining and grinding are thought to be dominated by empiricism, even a cursory inspection leads one to the conclusion that this results more from necessity arising out of the complicated and highly interdisciplinary nature of the processes than from the lack thereof. With these conditions in mind, the purpose of this paper is to outline the current understanding of strain rate effects in metals.

  4. Machining and grinding: High rate deformation in practice

    SciTech Connect

    Follansbee, P.S.

    1993-01-01

    Machining and grinding are well-established material-working operations involving highly non-uniform deformation and failure processes. A typical machining operation is characterized by uncertain boundary conditions (e.g.,surface interactions), three-dimensional stress states, large strains, high strain rates, non-uniform temperatures, highly localized deformations, and failure by both nominally ductile and brittle mechanisms. While machining and grinding are thought to be dominated by empiricism, even a cursory inspection leads one to the conclusion that this results more from necessity arising out of the complicated and highly interdisciplinary nature of the processes than from the lack thereof. With these conditions in mind, the purpose of this paper is to outline the current understanding of strain rate effects in metals.

  5. Measurement and analysis of forces in grinding of silicon nitride

    SciTech Connect

    Jahanmir, S.; Hwang, T.; Whitenton, E.P.; Job, L.S.; Evans, C.J.

    1995-12-31

    Using an instrumented surface grinder, the two components of grinding forces (normal and tangential) were measured for different types of silicon nitride ceramics. The influences of grinding parameters, such as down feed and table speed, and grinding fluids on forces were determined. In addition to these measurements, the specific grinding energy defined as the energy per unit volume of removed material was calculated. This parameter and the measured forces were then analyzed to determine possible correlations with mechanical properties of the silicon nitrides. It was found that, in general, the grinding forces and the specific grinding energy increase with the hardness. Both the grinding forces and the specific grinding energy were influenced by the grinding fluid and the grinding parameters. The implication of these results on the mechanisms of material removal in grinding of silicon nitride and the possible tribological effects are discussed.

  6. Surface topography of cylindrical gear wheels after smoothing in abrasive mass, honing and shot peening

    NASA Astrophysics Data System (ADS)

    Michalski, J.; Pawlus, P.; Żelasko, W.

    2011-08-01

    The present paper presents the analysis of surface topography of gear teeth as the result of final machining processes. Teeth of multiple cylindrical gears shaped by grinding were smoothed in abrasive mass, honed or shot peened. The measurement of gears were made using coordinate measuring machine and 3D surface topography stylus instrument. The following deviations were studied; pitch deviation, total pitches deviations, variation of teeth thickness and deviation of gear radial run-out. Changes in teeth surface topography during machining process were determined. 3D surface topography parameters, surface directionality as well as areal autocorrelation and power spectral density functions were taken into consideration. As the results of the analysis, the best surface topography with regard to gear operational properties was recommended.

  7. Chatter in a transverse grinding process

    NASA Astrophysics Data System (ADS)

    Yan, Yao; Xu, Jian; Wiercigroch, Marian

    2014-02-01

    In transverse grinding, the wheel moves along the workpiece, which induces unique grinding dynamics. To understand these dynamic phenomena, specifically the grinding chatter, a new dynamical model of the process is proposed, in which the wheel position is assumed to be quasi-static since the transverse wheel velocity is small. From the stability and bifurcation analyses of the chatter vibration, it appears that the dynamics of the process is governed by the quasi-static interactions. Moreover, the obtained results also show that the wheel and workpiece chatters are quite different, having continuous and intermittent characters respectively.

  8. Mass exchange during simultaneous grinding and dissolution

    SciTech Connect

    Aksel'rud, G.A.; Semenishin, E.M.; Kopyt, S.Ya.; Trotskii, V.I.

    1988-03-20

    Extraction of ore components of interest has a number of disadvantages, one of which being low efficiency. Combining the grinding and dissolution steps in one apparatus makes the process more efficient. Adoption of this technology, however, requires theoretical and mathematical studies. This paper reports the kinetics of simultaneous grinding and dissolution of copper-containing minerals. Simultaneous grinding and dissolution accelerated several fold the mass transfer of components of interest in the interaction of malachite and azurite with sulfuric acid solutions. The complete dissolution time was determined by adding the experimental rates of dissolution and abrasion.

  9. Automatic grinding apparatus to control uniform specimen thicknesses

    DOEpatents

    Bryner, J.S.

    1981-01-07

    This invention is directed to a new and improved grinding apparatus comprisng: (1) a movable grinding surface; (2) a specimen holder; (3) a dislacing means for moving the holder and/or grinding surface toward one another; and (4) at least three means for limiting displacement of the holder to the grinding surface.

  10. Shear-mode grinding force criteria of Zerodur and Pyrex

    NASA Astrophysics Data System (ADS)

    Hashimoto, Hiroshi; Imai, Kenichiro

    1995-08-01

    Experimental grinding of Zerodur and Pyrex demonstrated shear-mode grinding criteria (SM' GFC), which is a repeatable deterministic function of grinding conditions including materials and grinding wheels. Both criteria as with BK7 glass previously reported, are found to be the logarithmic function of removal rate.

  11. Automatic grinding apparatus to control uniform specimen thicknesses

    SciTech Connect

    Bryner, Joseph S.

    1982-01-01

    This invention is directed to a new and improved grinding apparatus comprising (1) a movable grinding surface, (2) a specimen holder, (3) a displacing device for moving the holder and/or grinding surface toward one another, and (4) at least three devices for limiting displacement of the holder to the grinding surface.

  12. High speed low damage grinding of advanced ceramics - Phase II Final Report

    SciTech Connect

    Kovach, J.A.; Malkin, S.

    2000-02-01

    In the manufacture of structural ceramic components, grinding costs can comprise up to 80% of the entire manufacturing cost. As a result, one of the most challenging tasks faced by manufacturing process engineers is the development of a ceramic finishing process to maximize part throughput while minimizing costs and associated scrap levels. The efforts summarized in this report represent the second phase of a program whose overall objective was to develop a single-step, roughing-finishing process suitable for producing high-quality silicon nitride parts at high material removal rates and at substantially lower cost than traditional, multi-stage grinding processes. More specifically, this report provides a technical overview of High-Speed, Low-Damage (HSLD) ceramic grinding which employs elevated wheel speeds to achieve the small grain depths of cut necessary for low-damage grinding while operating at relatively high material removal rates. The study employed the combined use of laboratory grinding tests, mathematical grinding models, and characterization of the resultant surface condition. A single-step, roughing-finishing process operating at high removal rates was developed and demonstrated.

  13. High Pressure Mass Spectrometry: The Generation of Mass Spectra at Operating Pressures Exceeding 1 Torr in a Microscale Cylindrical Ion Trap.

    PubMed

    Blakeman, Kenion H; Wolfe, Derek W; Cavanaugh, Craig A; Ramsey, J Michael

    2016-05-17

    We present the first demonstration of high pressure mass spectrometry (HPMS), which we define as mass spectrometry performed at pressures greater than 100 mTorr. Mass analysis is shown at operational pressures exceeding 1 Torr of helium buffer gas. A differentially pumped MS system was constructed for HPMS development consisting of two chambers. The first chamber (mass analysis chamber) was operated at pressures up to 1.2 Torr and contained the ionization source and a microscale cylindrical ion trap (CIT) mass analyzer. The CIT had critical dimensions of r0 = 500 μm and z0 = 650 μm. The second chamber was held at a lower pressure (≤10 mTorr) and contained an electron multiplier for detection. Mass spectra for xenon, 2-chloroethyl ethyl sulfide (CEES), and octane were acquired with helium buffer gas pressures ranging from 0.04 to 1.2 Torr in the mass analysis chamber. Full-width at half-maximum of mass spectral peaks was found to increase 143% for xenon, 40% for CEES, and 77% for octane over this pressure range, with maximum peak widths of 1.19, 1.26, and 0.82 Da, respectively. Data were fitted with an algebraic model that factors in ion-neutral collision peak broadening effects at high pressures. Experimental and theoretical peak broadening slopes showed good agreement at buffer gas pressures greater than 0.2 Torr. Experiments presented here demonstrate mass spectrometry at pressures orders of magnitude higher than conventionally practiced with any type of mass analyzer. The use of HPMS provides a way to eliminate turbo pumping requirements, leading to significant reduction in MS system size, weight, and power and facilitating a path toward compact/hand-held mass spectrometers with numerous potential applications. PMID:27109864

  14. Micromachining using ultrasonic impact grinding

    NASA Astrophysics Data System (ADS)

    Medis, Praveen S.; Thurman Henderson, H.

    2005-08-01

    Although largely unknown in the MEMS community, micromachining using ultrasonic impact grinding (UIG) is a fascinating yet easy fabrication scheme to achieve virtually any shape, such as a shallow or deep reservoir, a channel, a via, etc, in silicon, glass and other commonly used ceramic and semiconductor materials in the MEMS field. Because of the patterning and masking issues, etching even shallow channels or vias in a pre-processed silicon/glass/ceramic substrate is somewhat difficult, if not impossible. However, by using UIG one can achieve such structures, up to millimeters in depth in virtually no time. Furthermore, in silicon substrates, the orientation or any other physical dimension of the feature will no longer be constrained as in anisotropic etching by the crystallographic planes and directions; and in amorphous glass or ceramic substrates, features with vertical walls can be achieved, otherwise usually accomplished only by expensive laser ablation. Thus, the authors believe that this UIG process could open up many avenues to easily and quickly achieve the larger MEMS structures as well as packaging for both prototype and for production in silicon, glass and ceramic.

  15. Cylindrical geometry hall thruster

    DOEpatents

    Raitses, Yevgeny; Fisch, Nathaniel J.

    2002-01-01

    An apparatus and method for thrusting plasma, utilizing a Hall thruster with a cylindrical geometry, wherein ions are accelerated in substantially the axial direction. The apparatus is suitable for operation at low power. It employs small size thruster components, including a ceramic channel, with the center pole piece of the conventional annular design thruster eliminated or greatly reduced. Efficient operation is accomplished through magnetic fields with a substantial radial component. The propellant gas is ionized at an optimal location in the thruster. A further improvement is accomplished by segmented electrodes, which produce localized voltage drops within the thruster at optimally prescribed locations. The apparatus differs from a conventional Hall thruster, which has an annular geometry, not well suited to scaling to small size, because the small size for an annular design has a great deal of surface area relative to the volume.

  16. Effect of grinding conditions on the fatigue life of titanium 5Al-2.5Sn alloy

    NASA Technical Reports Server (NTRS)

    Rangaswamy, P.; Terutung, H.; Jeelani, S.

    1991-01-01

    An investigation into the effect of grinding conditions on the fatigue life of titanium 5Al-2.5Sn is presented. Damage to surface integrity and changes in the residual stresses distribution are studied to assess changes in fatigue life. A surface grinding machine, operating at speeds ranging from 2000 to 6000 fpm and using SiC wheels of grit sizes 60 and 120, was used to grind flat subsize specimens of 0.1-in. thickness. After grinding, the specimens were fatigued at a chosen stress and compared with the unadulterated material. A standard profilometer, a microhardness tester, and a scanning electron microscope were utilized to examine surface characteristics and measure roughness and hardness. Increased grinding speed in both wet and dry applications tended to decrease the fatigue life of the specimens. Fatigue life increased markedly at 2000 fpm under wet conditions, but then decreased at higher speeds. Grit size had no effect on the fatigue life.

  17. Production of Near-Mirror Surface Quality by Precision Grinding

    NASA Technical Reports Server (NTRS)

    Dimofte, Florin; Krantz, Timothy

    2003-01-01

    Mechanical components such as gears and bearings operate with the working surfaces in intimate contact with a mating part. The performance of such components will be influenced by the quality of the working surface. In general, a smoother surface will perform better than a rougher surface since the lubrication conditions are improved. For example, surfaces with a special near-mirror quality finish of low roughness performed better than ground surfaces when tested using a block-on-ring arrangement. Bearings with near-mirror quality have been tested and analyzed; lower running torques were measured and improved fatigue life was anticipated. Experiments have been done to evaluate the performance of gears with improved, low roughness surface finishing. The measured performance improvements include an increased scuffing (scoring) load capacity by a factor of 1.6, a 30-percent reduction of gear tooth running friction, and longer fatigue lives by a factor of about four. One can also anticipate that near-mirror quality surface finishing could improve the performance of other mechanical components such as mechanical seals and heavily loaded journal bearings. Given these demonstrated benefits, capable and economical methods for the production of mechanical components with near-mirror quality surfaces are desired. One could propose the production of near-mirror quality surfaces by several methods such as abrasive polishing, chemical assisted polishing, or grinding. Production of the surfaces by grinding offers the possibility to control the macro-geometry (form), waviness, and surface texture with one process. The present study was carried out to investigate the possibility of producing near-mirror quality surfaces by grinding. The present study makes use of a specially designed grinding machine spindle to improve the surface quality relative to the quality produced when using a spindle of conventional design.

  18. Comparison of High-Speed Operating Characteristics of Size 215 Cylindrical-Roller Bearings as Determined in Turbojet Engine and in Laboratory Test Rig

    NASA Technical Reports Server (NTRS)

    Macks, E Fred; Nemeth, Zolton N

    1951-01-01

    A comparison of the operating characteristics of 75-millimeter-bore (size 215) cylindrical-roller one-piece inner-race-riding cage-type bearings was made using a laboratory test rig and a turbojet engine. Cooling correlation parameters were determined by means of dimensional analysis, and the generalized results for both the inner- and outer-race bearing operating temperatures are compared for the laboratory test rig and the turbojet engine. Inner- and outer-race cooling-correlation curves were obtained for the turbojet-engine turbine-roller bearing with the same inner- and outer-race correlation parameters and exponents as those determined for the laboratory test-rig bearing. The inner- and outer-race turbine roller-bearing temperatures may be predicted from a single curve, regardless of variations in speed, load, oil flow, oil inlet temperature, oil inlet viscosity, oil-jet diameter or any combination of these parameters. The turbojet-engine turbine-roller-bearing inner-race temperatures were 30 to 60 F greater than the outer-race-maximum temperatures, the exact values depending on the operating condition and oil viscosity; these results are in contrast to the laboratory test-rig results where the inner-race temperatures were less than the outer-race-maximum temperatures. The turbojet-engine turbine-roller bearing, maximum outer-race circumferential temperature variation was approximately 30 F for each of the oils used. The effect of oil viscosity on inner- and outer-race turbojet-engine turbine-roller-bearing temperatures was found to be significant. With the lower viscosity oil (6x10(exp -7) reyns (4.9 centistokes) at 100 F; viscosity index, 83), the inner-race temperature was approximately 30 to 35 F less than with the higher viscosity oil (53x10(exp -7) reyns (42.8 centistokes) at 100 F; viscosity index, 150); whereas the outer-race-maximum temperatures were 12 to 28 F lower with the lower viscosity oil over the DN range investigated.

  19. Temperature prediction in high speed bone grinding using motor PWM signal.

    PubMed

    Tai, Bruce L; Zhang, Lihui; Wang, Anthony C; Sullivan, Stephen; Wang, Guangjun; Shih, Albert J

    2013-10-01

    This research explores the feasibility of using motor electrical feedback to estimate temperature rise during a surgical bone grinding procedure. High-speed bone grinding is often used during skull base neurosurgery to remove cranial bone and approach skull base tumors through the nasal corridor. Grinding-induced heat could propagate and potentially injure surrounding nerves and arteries, and therefore, predicting the temperature in the grinding region would benefit neurosurgeons during the operation. High-speed electric motors are controlled by pulse-width-modulation (PWM) to alter the current input and thus maintain the rotational speed. Assuming full mechanical to thermal power conversion in the grinding process, PWM can be used as feedback for heat generation and temperature prediction. In this study, the conversion model was established from experiments under a variety of grinding conditions and an inverse heat transfer method to determine heat flux. Given a constant rotational speed, the heat conversion was represented by a linear function, and could predict temperature from the experimental data with less than 20% errors. Such results support the advance of this technology for practical application. PMID:23806419

  20. Virtual Sensors for On-line Wheel Wear and Part Roughness Measurement in the Grinding Process

    PubMed Central

    Arriandiaga, Ander; Portillo, Eva; Sánchez, Jose A.; Cabanes, Itziar; Pombo, Iñigo

    2014-01-01

    Grinding is an advanced machining process for the manufacturing of valuable complex and accurate parts for high added value sectors such as aerospace, wind generation, etc. Due to the extremely severe conditions inside grinding machines, critical process variables such as part surface finish or grinding wheel wear cannot be easily and cheaply measured on-line. In this paper a virtual sensor for on-line monitoring of those variables is presented. The sensor is based on the modelling ability of Artificial Neural Networks (ANNs) for stochastic and non-linear processes such as grinding; the selected architecture is the Layer-Recurrent neural network. The sensor makes use of the relation between the variables to be measured and power consumption in the wheel spindle, which can be easily measured. A sensor calibration methodology is presented, and the levels of error that can be expected are discussed. Validation of the new sensor is carried out by comparing the sensor's results with actual measurements carried out in an industrial grinding machine. Results show excellent estimation performance for both wheel wear and surface roughness. In the case of wheel wear, the absolute error is within the range of microns (average value 32 μm). In the case of surface finish, the absolute error is well below Ra 1 μm (average value 0.32 μm). The present approach can be easily generalized to other grinding operations. PMID:24854055

  1. Design and fundamental understanding of Minimum Quantity Lubrication (MQL) assisted grinding using advanced nanolubricants

    NASA Astrophysics Data System (ADS)

    Kalita, Parash

    Abrasive grinding is widely used across manufacturing industry for finishing parts and components requiring smooth superficial textures and precise dimensional tolerances and accuracy. Unlike any other machining operations, the complex thermo-mechanical processes during grinding produce excessive friction-induced energy consumption, heat, and intense contact seizures. Lubrication and cooling from grinding fluids is crucial in minimizing the deleterious effects of friction and heat to maximize the output part quality and process efficiency. The conventional flood grinding approach of an uneconomical application of large quantities of chemically active fluids has been found ineffective to provide sufficient lubrication and produces waste streams and pollutants that are hazardous to human health and environment. Application of Minimum Quantity Lubrication (MQL) that cuts the volumetric fluid consumption by 3-4 orders of magnitude have been extensively researched in grinding as a high-productivity and environmentally-sustainable alternative to the conventional flood method. However, the lubrication performance and productivity of MQL technique with current fluids has been critically challenged by the extreme thermo-mechanical conditions of abrasive grinding. In this research, an MQL system based on advanced nanolubricants has been proposed to address the current thermo-mechanical challenges of MQL grinding and improve its productivity. The nanolubricants were composed of inorganic Molybdenum Disulphide nanoparticles (≈ 200 nm) intercalated with organic macromolecules of EP/AW property, dispersed in straight (base) oils---mineral-based paraffin and vegetable-based soybean oil. After feasibility investigations into the grindability of cast iron using MQL with nanolubricants, this research focused on the fundamental understanding of tribological behavior and lubricating mechanisms of nanolubricants as a method to improve the productivity of MQL-assisted surface grinding

  2. Utilisation of chip thickness models in grinding

    NASA Astrophysics Data System (ADS)

    Singleton, Roger

    Grinding is now a well established process utilised for both stock removal and finish applications. Although significant research is performed in this field, grinding still experiences problems with burn and high forces which can lead to poor quality components and damage to equipment. This generally occurs in grinding when the process deviates from its safe working conditions. In milling, chip thickness parameters are utilised to predict and maintain process outputs leading to improved control of the process. This thesis looks to further the knowledge of the relationship between chip thickness and the grinding process outputs to provide an increased predictive and maintenance modelling capability. Machining trials were undertaken using different chip thickness parameters to understand how these affect the process outputs. The chip thickness parameters were maintained at different grinding wheel diameters for a constant productivity process to determine the impact of chip thickness at a constant material removal rate.. Additional testing using a modified pin on disc test rig was performed to provide further information on process variables. The different chip thickness parameters provide control of different process outputs in the grinding process. These relationships can be described using contact layer theory and heat flux partitioning. The contact layer is defined as the immediate layer beneath the contact arc at the wheel workpiece interface. The size of the layer governs the force experienced during the process. The rate of contact layer removal directly impacts the net power required from the system. It was also found that the specific grinding energy of a process is more dependent on the productivity of a grinding process

  3. Cooling effectiveness of cutting fluid in creep feed grinding

    SciTech Connect

    Wang, S.B.; Kou, H.S.

    1997-10-01

    In this study, the heat transfer paths among the grinding fluid, the grains and the workpiece are investigated for the creep feed grinding. As heat enters the workpiece, the majority of heat is carried away by the fluid. Thus, the cooling effectiveness of the grinding fluid is defined and calculated through the application of the numerical method to illustrate how much the fraction of the heat is carried away by the grinding fluid. The results reveal that water has higher cooling effectiveness than oil. In addition, the cooling effect of the grinding fluid becomes more significant at lower workpiece speed, higher grinding depth and greater wheel speed.

  4. Surface integrity on grinding of gamma titanium aluminide intermetallic compounds

    NASA Astrophysics Data System (ADS)

    Murtagian, Gregorio Roberto

    Gamma-TiAl is an ordered intermetallic compound characterized by high strength to density ratio, good oxidation resistance, and good creep properties at elevated temperatures. However, it is intrinsically brittle at room temperature. This thesis investigates the potential for the use of grinding to process TiAl into useful shapes. Grinding is far from completely understood, and many aspects of the individual mechanical interactions of the abrasive grit with the material and their effect on surface integrity are unknown. The development of new synthetic diamond superabrasives in which shape and size can be controlled raises the question of the influence of those variables on the surface integrity. The goal of this work is to better understand the fundamentals of the abrasive grit/material interaction in grinding operations. Experimental, analytical, and numerical work was done to characterize and predict the resultant deformation and surface integrity on ground lamellar gamma-TiAl. Grinding tests were carried out, by analyzing the effects of grit size and shape, workpiece speed, wheel depth of cut, and wear on the subsurface plastic deformation depth (PDD). A practical method to assess the PDD is introduced based on the measurement of the lateral material flow by 3D non-contact surface profilometry. This method combines the quantitative capabilities of the microhardness measurement with the sensitivity of Nomarski microscopy. The scope and limitations of this technique are analyzed. Mechanical properties were obtained by quasi-static and split Hopkinson bar compression tests. Residual stress plots were obtained by x-ray, and surface roughness and cracking were evaluated. The abrasive grit/material interaction was accounted by modeling the force per abrasive grit for different grinding conditions, and studying its correlation to the PDD. Numerical models of this interaction were used to analyze boundary conditions, and abrasive size effects on the PDD. An explicit 2D

  5. Analysis on the grinding quality of palm oil fibers by using combined grinding equipment

    NASA Astrophysics Data System (ADS)

    Gan, H. L.; Gan, L. M.; Law, H. C.

    2015-12-01

    As known, Malaysia is the second largest palm oil producer worldwide after Indonesia, therefore indicating the abundance of its wastes within the country. The plantation would be seen to increase to at least 5.2 million ha by 2020, and the waste generation would be 50-70 times the plantation. However, the efficiency of bulk density is reduced. This is one of the main reasons of the initiation of this size reduction/ grinding research. With appropriate parameters, grinding will be seen to be helping in enhancing the inter-particle bindings, subsequently increasing the quality of final products. This paper focuses on the grinding quality involving palm oil wastes by using the Scanning Electron Microscope (SEM). The samples would first be ground to powder at varying grinding speed and finally got the randomly chosen particles measured to obtain the size range. The grinding speed was manipulated from 15 Hz to 40 Hz. From the data obtained, it was found the particles fineness increased with increasing grinding speed. In general, the size ranged from 45 μm to about 600 μm, where the finest was recorded at the speed of 40 Hz. It was also found that the binding was not so encouraging at very low speeds. Therefore, the optimum grinding speed for oil palm residues lied in the range of 25 Hz to 30 Hz. However, there were still limitations to be overcome if the accuracy of the image clarity is to be enhanced.

  6. Creep-feed grinding: A modern variant of the plane surface grinding process

    NASA Astrophysics Data System (ADS)

    Koenig, W.; Laeur-Schmaltz, H.

    1982-07-01

    Creep feed and conventional grinding are compared. Specifications for an automated combined plane surface - creep feed grinder are presented. It must be possible to preprogram two different grinding cycles with an intervening dressing cycles. The automatic grinder must be equipped with a rigid feed system for the two-stage process, which can provide a steplessly controlled, stick-slip - free workpiece speed over the range 0.01 to 30 m/min. Spindle drive and spindle bearings are to be adapted to the increased demands placed on the machine system by the plungecut grinding technique. An efficient coolant system must be available to provide high pressures and throughput quantities.

  7. Application of cryogenic grinding to achieve homogenization of transuranic wastes

    SciTech Connect

    Atkins, W.H.; Hill, D.D.; Lucero, M.E.; Jaramillo, L.; Martinez, H.E.

    1996-08-01

    This paper describes work done at Los Alamos National Laboratory (LANL) in collaboration with the Department of Energy Rocky Flats Field Office (DOE/RFFO) and with the National Institute of Standards and Technology (NIST), Boulder, Colorado. Researchers on this project have developed a method for cryogenic grinding of mixed wastes to homogenize and, thereby, to acquire a representative sample of the materials. There are approximately 220,000 waste drums owned by the Rocky Flats Environmental Technology Site (RFETS)-50,000 at RFETS and 170,000 at the Idaho National Engineering Laboratory. The cost of sampling the heterogeneous distribution of waste in each drum is prohibitive. In an attempt to produce a homogeneous mixture of waste that would reduce greatly the cost of sampling, researchers at NIST and RFETS are developing a cryogenic grinder. The Los Alamos work herein described addresses the implementation issues of the task. The first issue was to ascertain whether samples of the {open_quotes}small particle{close_quotes} mixtures of materials present in the waste drums at RFETS were representative of actual drum contents. Second, it was necessary to determine at what temperature the grinding operation must be performed in order to minimize or to eliminate the release of volatile organic compounds present in the waste. Last, it was essential to evaluate any effect the liquid cryogen might have on the structural integrity and ventilation capacity of the glovebox system. Results of this study showed that representative samples could be and had been obtained, that some release of organics occurred below freezing because of sublimation, and that operation of the cryogenic grinding equipment inside the glovebox was feasible.

  8. Working with the superabrasives industry to optimize tooling for grinding brittle materials

    SciTech Connect

    Taylor, J.S.; Piscotty, M.A.; Blaedel, K.L.; Gray, F.A.

    1996-05-01

    The optics manufacturing industry is undertaking a significant modernization, as computer-numeric-controlled (CNC) equipment is joining or replacing open-loop equipment and hand lapping/polishing on the shop floor. Several prototype CNC lens grinding platforms employing ring tools are undergoing development and demonstration at the Center for Optics Manufacturing in Rochester, NY, and several machine tool companies have CNC product lines aimed at the optics industry. Benefits to using CNC ring tool grinding equipment include: essentially unlimited flexibility in selecting radii of curvature without special radiused tooling, the potential for CIM linkages to CAD workstations, and the cultural shift from craftsmen with undocumented procedures to CNC machine operators employing computerized routines for process control. In recent years, these developments, have inspired a number of US optics companies to invest in CNC equipment and participate in process development activities involving bound diamond tooling. This modernization process,extends beyond large optics companies that have historically embraced advanced equipment, to also include smaller optical shops where a shift to CNC equipment requires a significant company commitment. This paper addresses our efforts to optimize fine grinding wheels to support the new generation of CNC equipment. We begin with a discussion of how fine grinding fits into the optical production process, and then describe an initiative for improving the linkage between optics industry and the grinding wheel industry. For the purposes of this paper, we define fine wheels to have diamond sizes below 20 micrometers, which includes wheels used for what is sometimes called medium grinding (e.g. 10-20 micrometers diamond) and for fine grinding (e.g. 2-4 micrometers diamond).

  9. 30 CFR 57.14115 - Stationary grinding machines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stationary grinding machines. 57.14115 Section... and Equipment Safety Devices and Maintenance Requirements § 57.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders, shall be equipped with— (a) Peripheral...

  10. 30 CFR 56.14115 - Stationary grinding machines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Stationary grinding machines. 56.14115 Section... Equipment Safety Devices and Maintenance Requirements § 56.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders, shall be equipped with— (a) Peripheral hoods capable...

  11. 30 CFR 56.14115 - Stationary grinding machines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Stationary grinding machines. 56.14115 Section... Equipment Safety Devices and Maintenance Requirements § 56.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders, shall be equipped with— (a) Peripheral hoods capable...

  12. 30 CFR 77.401 - Stationary grinding machines; protective devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Stationary grinding machines; protective... OF UNDERGROUND COAL MINES Safeguards for Mechanical Equipment § 77.401 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than special bit grinders shall be equipped...

  13. 30 CFR 56.14115 - Stationary grinding machines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Stationary grinding machines. 56.14115 Section... Equipment Safety Devices and Maintenance Requirements § 56.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders, shall be equipped with— (a) Peripheral hoods capable...

  14. 30 CFR 57.14115 - Stationary grinding machines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Stationary grinding machines. 57.14115 Section... and Equipment Safety Devices and Maintenance Requirements § 57.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders, shall be equipped with— (a) Peripheral...

  15. 30 CFR 57.14115 - Stationary grinding machines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Stationary grinding machines. 57.14115 Section... and Equipment Safety Devices and Maintenance Requirements § 57.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders, shall be equipped with— (a) Peripheral...

  16. 30 CFR 77.401 - Stationary grinding machines; protective devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Stationary grinding machines; protective... OF UNDERGROUND COAL MINES Safeguards for Mechanical Equipment § 77.401 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than special bit grinders shall be equipped...

  17. 30 CFR 56.14115 - Stationary grinding machines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Stationary grinding machines. 56.14115 Section... Equipment Safety Devices and Maintenance Requirements § 56.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders, shall be equipped with— (a) Peripheral hoods capable...

  18. 30 CFR 77.401 - Stationary grinding machines; protective devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Stationary grinding machines; protective... OF UNDERGROUND COAL MINES Safeguards for Mechanical Equipment § 77.401 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than special bit grinders shall be equipped...

  19. 30 CFR 57.14115 - Stationary grinding machines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Stationary grinding machines. 57.14115 Section... and Equipment Safety Devices and Maintenance Requirements § 57.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders, shall be equipped with— (a) Peripheral...

  20. 30 CFR 75.1723 - Stationary grinding machines; protective devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Stationary grinding machines; protective devices. 75.1723 Section 75.1723 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF....1723 Stationary grinding machines; protective devices. (a) Stationary grinding machines other...

  1. 30 CFR 75.1723 - Stationary grinding machines; protective devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Stationary grinding machines; protective devices. 75.1723 Section 75.1723 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF....1723 Stationary grinding machines; protective devices. (a) Stationary grinding machines other...

  2. 30 CFR 57.14115 - Stationary grinding machines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Stationary grinding machines. 57.14115 Section... and Equipment Safety Devices and Maintenance Requirements § 57.14115 Stationary grinding machines. Stationary grinding machines, other than special bit grinders, shall be equipped with— (a) Peripheral...

  3. 30 CFR 75.1723 - Stationary grinding machines; protective devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Stationary grinding machines; protective devices. 75.1723 Section 75.1723 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF....1723 Stationary grinding machines; protective devices. (a) Stationary grinding machines other...

  4. Simulation of Mid-Spatials from the Grinding Process

    NASA Astrophysics Data System (ADS)

    Pohl, M.; Börret, R.

    2016-02-01

    This paper focuses on the simulation of the creation of mid-spatial frequencies (mid-spatials) during the grinding process of optical components. The goal is to simulate this generation process and determine the correlating grinding parameters for mid-spatials. On this base, grinding parameters which lead to less mid-spatials could be determined.

  5. 7 CFR 58.726 - Cutting and grinding.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Cutting and grinding. 58.726 Section 58.726... Procedures § 58.726 Cutting and grinding. The trimmed and cleaned cheese should be cut into sections of convenient size to be handled by the grinder or shredder. The grinding and mixing of the blended lots...

  6. GRINDING ROOM AT SOUTHERN DUCTILE CASTING COMPANY, BESSEMER FOUNDRY SHOWING ...

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

    GRINDING ROOM AT SOUTHERN DUCTILE CASTING COMPANY, BESSEMER FOUNDRY SHOWING WHEELABORATOR THAT IMPALE SHOT AT TUMBLING CASTINGS TO REMOVE EXCESS SURFACE METALS AND SAND; ANNEALING OVENS TO HEAT CERTAIN CASTINGS TO ACHIEVE A DESIRED CHARACTERISTIC; AND GRINDING WHEELS USED TO REMOVE GATES. - Southern Ductile Casting Company, Grinding & Shipping, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

  7. 7 CFR 58.726 - Cutting and grinding.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Cutting and grinding. 58.726 Section 58.726... Procedures § 58.726 Cutting and grinding. The trimmed and cleaned cheese should be cut into sections of convenient size to be handled by the grinder or shredder. The grinding and mixing of the blended lots...

  8. 7 CFR 58.726 - Cutting and grinding.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Cutting and grinding. 58.726 Section 58.726... Procedures § 58.726 Cutting and grinding. The trimmed and cleaned cheese should be cut into sections of convenient size to be handled by the grinder or shredder. The grinding and mixing of the blended lots...

  9. Grinding Glass Disks On A Belt Sander

    NASA Technical Reports Server (NTRS)

    Lyons, James J., III

    1995-01-01

    Small machine attached to table-top belt sander makes possible to use belt sander to grind glass disk quickly to specified diameter within tolerance of about plus or minus 0.002 in. Intended to be used in place of production-shop glass grinder. Held on driveshaft by vacuum, glass disk rotated while periphery ground by continuous sanding belt.

  10. Physicochemical and grinding characteristics of dragonhead seeds

    NASA Astrophysics Data System (ADS)

    Dziki, D.; Miś, A.; Gładyszewska, B.; Laskowski, J.; Kwiatkowski, S.; Gawlik-Dziki, U.

    2013-12-01

    The results of investigations on the physicochemical and grinding characteristics of Moldavian dragonhead seeds are presented. The data obtained showed that the physical properties (average size, sphericity, surface area, 1 000 seed mass, dynamic angle of repose, coefficient of static friction, and bulk and true densities) of the white and blue form of dragonhead seeds were not significantly different. Both forms of dragonhead showed similar levels of protein (average of 21%), whereas the blue form of dragonhead had a lower fat content (average of 23.1%) and higher mucilage content (13.35%) in comparison to the blue form of seed (24.6 and 9.95%, respectively). Antioxidant capacity of dragonhead seeds was comparable for both forms and averaged about 40%, which corresponded to EC50 values of 0.12 and 0.13 mgml-1 for the white and blue forms, respectively. The grinding material showed similar particle size distribution of ground material for both forms of dragonhead seeds. The lowest values of specific grinding energy were obtained for the white form of dragonhead seeds, those for the blue form were significantly higher. Grinding of dragonhead seeds using a screen 2.0 mm mesh size caused screen hole clogging. This problem did not occur when dragonhead seeds were mixed with wheat grain.

  11. Carving up Word Meaning: Portioning and Grinding

    ERIC Educational Resources Information Center

    Frisson, S.; Frazier, L.

    2005-01-01

    Two eye-tracking experiments investigated the processing of mass nouns used as count nouns and count nouns used as mass nouns. Following Copestake and Briscoe (1995), the basic or underived sense of a word was treated as the input to a derivational rule (''grinding'' or ''portioning'') which produced the derived sense as output. It was…

  12. Precision replenishable grinding tool and manufacturing process

    DOEpatents

    Makowiecki, Daniel M.; Kerns, John A.; Blaedel, Kenneth L.; Colella, Nicholas J.; Davis, Pete J.; Juntz, Robert S.

    1998-01-01

    A reusable grinding tool consisting of a replaceable single layer of abrasive particles intimately bonded to a precisely configured tool substrate, and a process for manufacturing the grinding tool. The tool substrate may be ceramic or metal and the abrasive particles are preferably diamond, but may be cubic boron nitride. The manufacturing process involves: coating a configured tool substrate with layers of metals, such as titanium, copper and titanium, by physical vapor deposition (PVD); applying the abrasive particles to the coated surface by a slurry technique; and brazing the abrasive particles to the tool substrate by alloying the metal layers. The precision control of the composition and thickness of the metal layers enables the bonding of a single layer or several layers of micron size abrasive particles to the tool surface. By the incorporation of an easily dissolved metal layer in the composition such allows the removal and replacement of the abrasive particles, thereby providing a process for replenishing a precisely machined grinding tool with fine abrasive particles, thus greatly reducing costs as compared to replacing expensive grinding tools.

  13. Precision replenishable grinding tool and manufacturing process

    DOEpatents

    Makowiecki, D.M.; Kerns, J.A.; Blaedel, K.L.; Colella, N.J.; Davis, P.J.; Juntz, R.S.

    1998-06-09

    A reusable grinding tool consisting of a replaceable single layer of abrasive particles intimately bonded to a precisely configured tool substrate, and a process for manufacturing the grinding tool are disclosed. The tool substrate may be ceramic or metal and the abrasive particles are preferably diamond, but may be cubic boron nitride. The manufacturing process involves: coating a configured tool substrate with layers of metals, such as titanium, copper and titanium, by physical vapor deposition (PVD); applying the abrasive particles to the coated surface by a slurry technique; and brazing the abrasive particles to the tool substrate by alloying the metal layers. The precision control of the composition and thickness of the metal layers enables the bonding of a single layer or several layers of micron size abrasive particles to the tool surface. By the incorporation of an easily dissolved metal layer in the composition such allows the removal and replacement of the abrasive particles, thereby providing a process for replenishing a precisely machined grinding tool with fine abrasive particles, thus greatly reducing costs as compared to replacing expensive grinding tools. 11 figs.

  14. Automated Inspection And Precise Grinding Of Gears

    NASA Technical Reports Server (NTRS)

    Frint, Harold; Glasow, Warren

    1995-01-01

    Method of precise grinding of spiral bevel gears involves automated inspection of gear-tooth surfaces followed by adjustments of machine-tool settings to minimize differences between actual and nominal surfaces. Similar to method described in "Computerized Inspection of Gear-Tooth Surfaces" (LEW-15736). Yields gears of higher quality, with significant reduction in manufacturing and inspection time.

  15. Smooth brome (Bromus inermis Leyss) response to concrete grinding residue application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Concrete grinding residue (CGR) is a slurry byproduct created by concrete pavement maintenance operations. The application of CGR to roadside soils is not consistently regulated by state agencies across the United States. Much of this variability in regulation may be due to the lack of science-base...

  16. Electronic BAR Gauge: a customized optical rail profile measurement system for rail-grinding applications

    NASA Astrophysics Data System (ADS)

    Bachinsky, Gordon S.

    1995-06-01

    The dynamic interaction that occurs at the rail/wheel interface of any rail system is significantly influenced by rail and wheel profiles. In an effort to enhance this interaction, railways and transit systems often employ rail grinding as a means to maintain a defined rail profile. The cost to perform this procedure can be very high, sometimes exceeding $DLR25,000 per day for the use of a large grinding machine (with up to 128 grinding motors-each motor being 20 hp or more). Because of this, it is imperative that the work be done efficiently and accurately. In recent years there has been substantial research into the optimization of rail profiles. The National Research Council (NRC) of Canada is one research facility that has generated a unique, precise set of specified profiles for use in heavy-haul railway operations. To implement these profiles in a consistent manner, during rail grinding operations, requires some type of measurement system that provides feedback to the field staff. Up until recently, this has been accomplished with a manual BAR gauge that is fitted with a set of accurate profile templates. The BAR gauge, which initially was fitted with four specified templates, is now equipped with ten such templates. To obtain the full potential of benefits from these profiles requires more precise grinding than that which has been achieved in the past. The other problem with the current manual profile measurement (BAR) method is that it is somewhat slow and cumbersome and the differences between profiles is quite small (i.e. 0.020 inch or less). In order to enhance their rail grinding management support, ARM pursued an automated system that would optically measure rail profiles very fast and accurately from a hy-rail vehicle and compare them with the NRC profiles. Another important feature that was desired in this system was the ability to measure the relative position of one profile with respect to the other (i.e. left versus right rail). Such a system

  17. Study of the potential of three different MgB2 tapes for application in cylindrical coils operating at 20 K

    NASA Astrophysics Data System (ADS)

    Pitel, J.; Kováč, P.; Tropeano, M.; Grasso, G.

    2015-05-01

    The goal of this theoretical study is to illustrate the potential of three different MgB2 tapes, developed by Columbus Superconductors, for application in cylindrical coils. First, the distribution of critical currents and electric fields of individual turns is compared when the winding of the model coil is made with tapes having different Ic(B) and anisotropy values. Second, the influence of the winding geometry on basic parameters of cylindrical coils which consist of a set of pancake coils, such as critical current Icmin, central magnetic field B0 and stored energy E, is analysed. The winding geometry of the coils, i.e. the outer winding radius and the coil length, with the same inner winding radius, was changed from a disc shape to a long thin solenoid in such a way that the overall tape length was held constant, and considered as a parameter. Finally, the winding cross-section of the coil is optimized with respect to the constant tape length in order to reach the maximum central field. The results of calculations show that for a given overall tape length and inner winding radius there exists only one winding geometry which generates the maximum central field. The overall tape length, as a parameter, is changed in a broad range from 500 m to 10 km. All calculations were performed using the experimental data measured at 20 K while the effect of the anisotropy in the Ic(B) characteristic of the short samples is taken into account.

  18. First Grinding of a Rock on Mars

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The round, shallow depression in this image resulted from history's first grinding of a rock on Mars. The rock abrasion tool on NASA's Spirit rover ground off the surface of a patch 45.5 millimeters (1.8 inches) in diameter on a rock called Adirondack during Spirit's 34th sol on Mars, Feb. 6, 2004. The hole is 2.65 millimeters (0.1 inch) deep, exposing fresh interior material of the rock for close inspection with the rover's microscopic imager and two spectrometers on the robotic arm. This image was taken by Spirit's panoramic camera, providing a quick visual check of the success of the grinding. The rock abrasion tools on both Mars Exploration Rovers were supplied by Honeybee Robotics, New York, N.Y.

  19. Cylindrical neutron generator

    DOEpatents

    Leung, Ka-Ngo

    2009-12-29

    A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

  20. Cylindrical neutron generator

    DOEpatents

    Leung, Ka-Ngo

    2008-04-22

    A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

  1. Cylindrical neutron generator

    DOEpatents

    Leung, Ka-Ngo

    2005-06-14

    A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

  2. Cylindrically symmetric wormholes

    SciTech Connect

    Kuhfittig, Peter K.F.

    2005-05-15

    This paper discusses traversable wormholes that differ slightly but significantly from those of the Morris-Thorne type under the assumption of cylindrical symmetry. The throat is a piecewise smooth cylindrical surface resulting in a shape function that is not differentiable at some value. It is proposed that the regular derivative be replaced by a one-sided derivative at this value. The resulting wormhole geometry satisfies the weak energy condition.

  3. The effect of geometry and operation conditions on the performance of a gas-liquid cylindrical cyclone separator with new structure

    NASA Astrophysics Data System (ADS)

    Han, Qing; Zhang, Chi; Xu, Bo; Chen, Jiangping

    2013-07-01

    The hydrodynamic flow behavior, effects of geometry and working conditions of a gas-liquid cylindrical cyclone separator with a new structure are investigated by computational fluid dynamic and experiment. Gas liquid cylindrical cyclone separator is widely used in oil industry, refrigeration system because of its simple structure, high separating efficiency, little maintenance and no moving parts nor internal devices. In this work, a gas liquid cylindrical cyclone separator with new structure used before evaporator in refrigeration system can remove the vapor from the mixture and make evaporator compact by improving its heat exchange efficiency with the lower inlet quality. It also decreases evaporator pressure drop and reduces compressor work. The two pipes are placed symmetrically which makes each of them can be treated as inlet. It means when the fluids flow reverse, the separator performance will not be influence. Four samples with different geometry parameters are tested by experiment with different inlet quality (0.18-0.33), inlet mass flow rate (65-100kg/h). Compared with the experimental data, CFD simulation results show a good agreement. Eulerian multiphase model and Reynolds Stress Turbulence model are applied in the CFD simulation and obtained the inner flow field such as phase path lines, tangential velocity profiles and pressure and volume of fraction distribution contours. The separator body diameter (24, 36, 48mm) and inlet diameter (3.84, 4.8, 5.76mm) decide the maximum tangential velocity which results in the centrifugal force. The tangential velocity profiles are simulated and compared among different models. The higher tangential velocity makes higher quality of gas outlet but high pressure drop at the same time. Decreasing the inlet diameter increases quality of gas outlet pipe and pressure drop. High gas outlet quality is cost at high pressure drop. Increasing of separator diameter makes gas outlet quality increase first and then decrease but

  4. Dressing of diamond grinding wheels by abrasive water jet for freeform optical surface grinding

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Yao, Peng; Li, Chengwu; Huang, Chuanzhen; Wang, Jun; Zhu, Hongtao; Liu, Zengwen

    2014-08-01

    During the ultra-precision grinding of a large aperture mirror made of RB-SiC, the grinding wheel becomes dull rapidly, which will lead to an increase of grinding force and a decrease of grinding ratio. In this paper, diamond grinding sticks were dressed with micro SiC abrasive water jet and water jet. Through single factorial experiments, the influence of jet pressure on the dressing performance was investigated. To analyze and evaluate the effect of dressing quantitatively, the 3D roughness and the wheel topography were measured and compared with laser scanning confocal microscope before and after dressing. The experimental results show that the abrasive grains are well protruded from binder and the distribution of the abrasive grains becomes uniform after dressing by abrasive water jet when the dressing parameters are properly selected. The dressing performance of abrasive water jet is much better than water jet. For dressing ultra-fine grit size wheels, the abrasive size of the jet should be smaller than the wheel grit size to achieve a better result. The jet pressure is an obvious influence factor of the surface topography.

  5. Freeform grinding and polishing with PROSurf

    NASA Astrophysics Data System (ADS)

    Wolfs, Franciscus; Fess, Edward; DeFisher, Scott; Torres, Josh; Ross, James

    2015-10-01

    Recently, the desire to use freeform optics has been increasing, including shapes such as torics and anamorphic aspheres. Freeform optics can be used to expand capabilities of optical systems. They can compensate for limitations in rotationally symmetric optics. These same traits that give freeform optics the ability to improve optical systems also makes them more challenging to manufacture. This holds true for grinding, polishing, and metrology. As freeform optics become more prevalent in the industry, tolerances will become more stringent, requiring deterministic manufacturing processes. To generate freeforms, it is crucial to have control over all aspects of the process. Controlling the surface definition is important for achieving a better surface finish during processing. Metrology will be required to adjust tool paths at various stages in manufacturing. During grinding, metrology will be used to adjust tool positions relative to the nominal tool path to compensate for repeatable machine and tooling error. For polishing, metrology will be used to deterministically adjust dwell relative to the amount of the error in different surface locations, allowing for convergence towards the desired surface at a uniform rate. OptiPro has developed PROSurf, a CAM software package for creating freeform tool paths and applying metrology-based corrections. The software can be used for both grinding and polishing freeform optics. The software has flexibility to allow for different methods of modelling the surface: mathematical equations, solid models, and point clouds. The software is designed to make it easier to manufacture and polish complex freeform optics.

  6. Material and process issues in electrolytic in-process dressing (ELID)-grinding

    NASA Astrophysics Data System (ADS)

    Chen, Hong

    This research covers research and development of the electrolytic in-process dressing (ELID) grinding technology, where material and process issues are systematically investigated. Experiments on anodic oxidation of cast iron and bronze were performed to determine the growth behavior of the oxides on the metals, their structures and mechanical properties. With SEM and optical microscope, a special technique to measure the oxide thickness was also developed. A series of theoretical calculations was carried out to highlight the fact that the localized dissolution of the metals around diamond particle results in exposing the cutting edge for efficient grinding and/or cutting. A model was proposed on the basis of experimental observations and theoretical calculations. It was the first quantitative model that explores the ELID mechanism and could serve guidance to optimize ELID-grinding operations for many applications. This model recognized the key feature of the oxide layer in the process, formulated the dynamic balance between its growth and wear, and emphasized the important role of its nonlinear growth. It not only brought a link between performance and process parameters, but also explained the experimental results and helped ELID-grinding practice. Grinding experiments performed on OPTICAM PM showed that with a proper selection of operation parameters from the proposed model, (1) ELID-grinding improved surface roughness (RMS) a factor of five for Zerodur; (2) Ductile grinding modes were achieved for Zerodur, BK-7 and SF-6; (3) Mirror finish (RMS < 500 A) and low subsurface damage (depth < 1.5 μm) for 4-inch silicon wafers were produced within 5 minutes; and (4) the three requirements of high precision optical grinding were achieved simultaneously on BK-7: high surface accuracy (flatness < 0.15/ /mum), low subsurface damage (depth < 2/ /mum) and good surface finish (RMS < 500 A). An ELID-cutting system was designed and developed. It consists of a modified cut

  7. Aroma recovery from roasted coffee by wet grinding.

    PubMed

    Baggenstoss, J; Thomann, D; Perren, R; Escher, F

    2010-01-01

    Aroma recovery as determined by solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) was compared in coffees resulting from conventional grinding processes, and from wet grinding with cold and hot water. Freshly roasted coffee as well as old, completely degassed coffee was ground in order to estimate the relationship of internal carbon dioxide pressure in freshly roasted coffee with the aroma loss during grinding. The release of volatile aroma substances during grinding was found to be related to the internal carbon dioxide pressure, and wet grinding with cold water was shown to minimize losses of aroma compounds by trapping them in water. Due to the high solubility of roasted coffee in water, the use of wet-grinding equipment is limited to processes where grinding is followed by an extraction step. Combining grinding and extraction by the use of hot water for wet grinding resulted in considerable losses of aroma compounds because of the prolonged heat impact. Therefore, a more promising two-step process involving cold wet grinding and subsequent hot extraction in a closed system was introduced. The yield of aroma compounds in the resulting coffee was substantially higher compared to conventionally ground coffee. PMID:21535580

  8. Influence of grain size on the grinding response of alumina

    SciTech Connect

    Xu, H.H.K.; Wei, L.; Jahanmir, S.

    1996-05-01

    The effect of grain size on the grinding response, i.e., grinding forces, surface roughness, and grinding-induced subsurface damage, is investigated in a series of alumina ceramics with the average grain size ranging from 3 to 35 {micro}m. The grinding forces are measured as a function of depth of cut in surface grinding. It is found that the grinding forces decrease as the grain size is increased from 3 to 9 {micro}m. But at larger grain sizes, the grinding forces are independent of the grain size. Subsurface damage in grinding is observed using a bonded-interface sectioning technique. The subsurface damage is found to consist of intragrain twin/slip bands and intergranular microcracks. The density of grinding-induced subsurface microcracks increases with the grain size. In addition to using optical microscopy on the sections of the ground specimens, a nondestructive thermal wave measurement technique is used directly on the ground surfaces for the detection of grinding-induced subsurface microcracks. The grain size dependence of the microcrack density estimated from the thermal images is found to agree with the results obtained using the bonded-interface technique.

  9. A Wavelet-Based Methodology for Grinding Wheel Condition Monitoring

    SciTech Connect

    Liao, T. W.; Ting, C.F.; Qu, Jun; Blau, Peter Julian

    2007-01-01

    Grinding wheel surface condition changes as more material is removed. This paper presents a wavelet-based methodology for grinding wheel condition monitoring based on acoustic emission (AE) signals. Grinding experiments in creep feed mode were conducted to grind alumina specimens with a resinoid-bonded diamond wheel using two different conditions. During the experiments, AE signals were collected when the wheel was 'sharp' and when the wheel was 'dull'. Discriminant features were then extracted from each raw AE signal segment using the discrete wavelet decomposition procedure. An adaptive genetic clustering algorithm was finally applied to the extracted features in order to distinguish different states of grinding wheel condition. The test results indicate that the proposed methodology can achieve 97% clustering accuracy for the high material removal rate condition, 86.7% for the low material removal rate condition, and 76.7% for the combined grinding conditions if the base wavelet, the decomposition level, and the GA parameters are properly selected.

  10. Grinding tool for making hemispherical bores in hard materials

    DOEpatents

    Duran, E.L.

    1985-04-03

    A grinding tool for forming hemispherical bores in hard materials such as boron carbide. The tool comprises a hemicircular grinding bit, formed of a metal bond diamond matrix, which is mounted transversely on one end of a tubular tool shaft. The bit includes a spherically curved outer edge surface which is the active grinding surface of the tool. Two coolant fluid ports on opposite sides of the bit enable introduction of coolant fluid through the bore of the tool shaft so as to be emitted adjacent the opposite sides of the grinding bit, thereby providing optimum cooling of both the workpiece and the bit.

  11. Observations on the grinding of alumina with variations in belt speed, load, sample rotation, and grinding fluids

    SciTech Connect

    Schwartz, C.J.; Bahadur, S.

    1998-07-01

    The volume of material removed in the grinding of alumina on a diamond-impregnated grinding belt was studied. Four grinding process parameters were tested: belt speed, normal load at the pin's contact surface, sample rotation during grinding, and grinding fluid. The results showed that at low loads the belts speed did not have a significant effect on material removal rates; however, the material removal rate decreased at higher loads combined with higher speeds. It decreased, in particular, when the sample was also rotated. Of the fluids used, the 50% ethylene glycol--50% water mixture produced the highest material removal rates while the lowest were produced by biodegradable soybean oil. The test conditions that produced high temperatures at the contact surface contributed to plowing as opposed to cutting and resulted in reduced material removal rates. The reasons for these variations were investigated by scanning electron microscopy of the surfaces, which revealed evidence of plastic deformation and temperature rise during grinding.

  12. Learning Activity Packets for Grinding Machines. Unit I--Grinding Machines.

    ERIC Educational Resources Information Center

    Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This learning activity packet (LAP) is one of three that accompany the curriculum guide on grinding machines. It outlines the study activities and performance tasks for the first unit of this curriculum guide. Its purpose is to aid the student in attaining a working knowledge of this area of training and in achieving a skilled or moderately…

  13. Learning Activity Packets for Grinding Machines. Unit II--Surface Grinding.

    ERIC Educational Resources Information Center

    Oklahoma State Board of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    This learning activity packet (LAP) is one of three that accompany the curriculum guide on grinding machines. It outlines the study activities and performance tasks for the second unit of this curriculum guide. Its purpose is to aid the student in attaining a working knowledge of this area of training and in achieving a skilled or moderately…

  14. Application of copper nanoparticles as additions to a grinding fluid to increase the quality of grinding of magnetic ceramic materials

    NASA Astrophysics Data System (ADS)

    Krevchik, V. D.; Skryabin, V. A.; Sokolov, A. V.; Men'shova, S. B.; Artemov, I. I.; Prokof'ev, M. V.; Karasev, N. Ya.

    2015-12-01

    The influence of copper nanoparticles in a grinding fluid (GF) used for grinding on the characteristics of the surface layer of ferrite parts and their service properties is studied. Profilograms of the ground surfaces and their roughness are measured. The electromagnetic losses of 10000NN ferrite parts ground in an GF medium with copper nanoparticles are estimated. The use of metal nanoparticles as additions to a grinding fluid is shown to be useful for processing of brittle nonmetallic materials.

  15. On-machine precision preparation and dressing of ball-headed diamond wheel for the grinding of fused silica

    NASA Astrophysics Data System (ADS)

    Chen, Mingjun; Li, Ziang; Yu, Bo; Peng, Hui; Fang, Zhen

    2013-09-01

    In the grinding of high quality fused silica parts with complex surface or structure using ball-headed metal bonded diamond wheel with small diameter, the existing dressing methods are not suitable to dress the ball-headed diamond wheel precisely due to that they are either on-line in process dressing which may causes collision problem or without consideration for the effects of the tool setting error and electrode wear. An on-machine precision preparation and dressing method is proposed for ball-headed diamond wheel based on electrical discharge machining. By using this method the cylindrical diamond wheel with small diameter is manufactured to hemispherical-headed form. The obtained ball-headed diamond wheel is dressed after several grinding passes to recover geometrical accuracy and sharpness which is lost due to the wheel wear. A tool setting method based on high precision optical system is presented to reduce the wheel center setting error and dimension error. The effect of electrode tool wear is investigated by electrical dressing experiments, and the electrode tool wear compensation model is established based on the experimental results which show that the value of wear ratio coefficient K' tends to be constant with the increasing of the feed length of electrode and the mean value of K' is 0.156. Grinding experiments of fused silica are carried out on a test bench to evaluate the performance of the preparation and dressing method. The experimental results show that the surface roughness of the finished workpiece is 0.03 μm. The effect of the grinding parameter and dressing frequency on the surface roughness is investigated based on the measurement results of the surface roughness. This research provides an on-machine preparation and dressing method for ball-headed metal bonded diamond wheel used in the grinding of fused silica, which provides a solution to the tool setting method and the effect of electrode tool wear.

  16. Examining Cylindrical Dice

    ERIC Educational Resources Information Center

    Jones, Dustin L.

    2009-01-01

    The author describes an activity where prospective mathematics teachers made hypotheses about the dimensions of a fair cylindrical die and conducted experiments with different cylinders. He also provides a model that estimates the probability that a cylinder would land on the lateral surface, depending on the height and diameter of the cylinder.…

  17. Dependence of rates of breakage on fines content in wet ball mill grinding

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Anirban

    The following research fundamentally deals with the cause and implications of nonlinearities in breakage rates of materials in wet grinding systems. The innate dependence of such nonlinearities on fines content and the milling environment during wet grinding operations is also tested and observed. Preferential breakage of coarser size fractions as compared to the finer size fractions in a particle population were observed and discussed. The classification action of the pulp was deemed to be the probable cause for such a peculiarity. Ores with varying degrees of hardness and brittleness were used for wet grinding experiments, primarily to test the variations in specific breakage rates as a function of varying hardness. For this research, limestone, quartzite, and gold ore were used. The degree of hardness is of the order of: limestone, quartzite, gold ore. Selection and breakage function parameters were determined in the course of this research. Functional forms of these expressions were used to compare experimentally derived parameter estimates. Force-fitting of parameters was not done in order to examine the realtime behavior of particle populations in wet grinding systems. Breakage functions were established as being invariant with respect to such operating variables like ball load, mill speed, particle load, and particle size distribution of the mill. It was also determined that specific selection functions were inherently dependent on the particle size distribution in wet grinding systems. Also, they were consistent with inputs of specific energy, according to grind time. Nonlinearity trends were observed for 1st order specific selection functions which illustrated variations in breakage rates with incremental inputs of grind time and specific energy. A mean particle size called the fulcrum was noted below which the nonlinearities in the breakage trends were observed. This magnitude of the fulcrum value varied with percent solids and slurry filling, indicating

  18. 7 CFR 58.726 - Cutting and grinding.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Cutting and grinding. 58.726 Section 58.726 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Procedures § 58.726 Cutting and grinding. The trimmed and cleaned cheese should be cut into sections...

  19. 7 CFR 58.726 - Cutting and grinding.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Cutting and grinding. 58.726 Section 58.726 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards... Procedures § 58.726 Cutting and grinding. The trimmed and cleaned cheese should be cut into sections...

  20. 30 CFR 56.14115 - Stationary grinding machines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Stationary grinding machines. 56.14115 Section 56.14115 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND... Equipment Safety Devices and Maintenance Requirements § 56.14115 Stationary grinding machines....

  1. 30 CFR 75.1723 - Stationary grinding machines; protective devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... devices. 75.1723 Section 75.1723 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF....1723 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than special bit grinders shall be equipped with: (1) Peripheral hoods (less than 90° throat openings)...

  2. 30 CFR 75.1723 - Stationary grinding machines; protective devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... devices. 75.1723 Section 75.1723 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF....1723 Stationary grinding machines; protective devices. (a) Stationary grinding machines other than special bit grinders shall be equipped with: (1) Peripheral hoods (less than 90° throat openings)...

  3. Surface-figuring CVD-SiC mirrors with a five-axis-control ultraprecision grinding machine

    NASA Astrophysics Data System (ADS)

    Namba, Yoshiharu; Suzuki, Hiroshi

    1997-11-01

    A large 5-axis control ultraprecision grinding machine has been developed for making synchrotron-radiation mirrors with high accuracy. The positional and angular resolutions of the machine are 10 nm and 0.0002 degree, respectively. The dimensions of the machine are 3.3 m by 2.7 m by 4.4 m in height. The machine can generate non-axisymmetric aspheric surfaces on CVD-SiC material by a disc-type metal-bonded diamond wheel. An electric micrometer has been set near a grinding head for measuring the form error of ground surface in conformity with the machine movement due to the cutter location data. A series of the measured form errors corrects the former cutter location data automatically and the next grinding operation will be performed by the new cutter location data. A CVD-SiC material of 510 mm by 110 mm was ground into a toroidal surface of 750 nm in shape accuracy by the fifth grinding operation with the fourth correction of cutter location data. More than 99% of toroidal surface area have a form accuracy less than 500 nm. 3.3 nm rms surface roughness was obtained by the ultraprecision grinding using a SD4000N150M metal-bonded diamond wheel.

  4. Dynamical aspects in modeling long cantilevering workpieces in tool grinding

    NASA Astrophysics Data System (ADS)

    de Payrebrune, K. M.; Kröger, M.

    2015-10-01

    Tool grinding is a complex process in which temporal dynamics of workpiece and grinding wheel, and the material removal process itself, affect the quality of the workpiece. Many existing models already provide the option to study the dynamics of workpiece and grinding wheel or cutting forces and material removal processes, but mostly do not combine these aspects. Here, workpiece dynamics are studied in relation to its structural and geometrical changing properties during machining, and are used to simulate the vibrations and deformation of the workpiece during grinding. In combination with models for the grinding wheel and the material removal process, dependencies of the workpiece dynamics on the workpieces quality are studied and results from this hybrid model are in excellent agreement with empirical measurements. Furthermore, the results demonstrate the significant effects of deformations of the workpiece on its final geometry.

  5. Three-dimensional measurement and characterization of grinding tool topography

    NASA Astrophysics Data System (ADS)

    Cui, Changcai; Blunt, Liam; Jiang, Xiangqian; Xu, Xipeng; Huang, Hui; Ye, Ruifang

    2013-01-01

    A comprehensive 3-dimensional measurement and characterization method for grinding tool topography was developed. A stylus instrument (SOMICRONIC, France) was used to measure the surface of a metal-bonded diamond grinding tool. The sampled data was input the software SurfStand developed by Centre for Precision Technology (CPT) for reconstruction and further characterization of the surface. Roughness parameters pertaining to the general surface and specific feature parameters relating to the grinding grits, such as height and angle peak curvature have been calculated. The methodology of measurement has been compared with that using an optical microscope. The comparison shows that the three-dimensional characterization has distinct advantages for grinding tool topography assessment. It is precise, convenient and comprehensive so it is suitable for precision measurement and analysis where an understanding of the grinding tool and its cutting ability are required.

  6. Cylindrically symmetric electrohydrodynamic patterning.

    PubMed

    Deshpande, Paru; Pease, Leonard F; Chen, Lei; Chou, Stephen Y; Russel, William B

    2004-10-01

    Cylindrically symmetric structures such as concentric rings and rosettes arise out of thin polymeric films subjected to strong electric fields. Experiments that formed concentric rings and theory capable of explaining these and other cylindrical structures are presented. These rings represent an additional member of a class of structures, including pillars and holes, formed by electrohydrodynamic patterning of thin films, occasionally referred to as lithographically induced self-assembly. Fabrication of a set of concentric rings begins by spin coating a thin poly(methyl methacrylate) film onto a silicon wafer. A mask is superimposed parallel to the film leaving a similarly thin air gap. Electric fields, acting in opposition to surface tension, destabilize the free interface when raised above the glass transition temperature. Central pillars nucleate under small cylindrical protrusions patterned on the mask. Rings then emerge sequentially, with larger systems having as many as 10 fully formed rings. Ring-to-ring spacings and annular widths, typically on the order of a micron, are approximately constant within a concentric cluster. The formation rate is proportional to the viscosity and, consequently, has the expected Williams-Landel-Ferry dependence on temperature. In light of these developments we have undertaken a linear stability analysis in cylindrical coordinates to describe these rings and ringlike structures. The salient feature of this analysis is the use of perturbations that incorporate their radial dependence in terms of Bessel functions as opposed to the traditional sinusoids of Cartesian coordinates. The theory predicts approximately constant ring-to-ring spacings, constant annular widths, and growth rates that agree with experiment. A secondary instability is observed at higher temperatures, which causes the rings to segment into arcs or pillar arrays. The cylindrical theory may be generalized to describe hexagonal pillar/hole packing, gratings, and

  7. Cylindrically polarized nondiffracting optical pulses

    NASA Astrophysics Data System (ADS)

    Ornigotti, Marco; Conti, Claudio; Szameit, Alexander

    2016-07-01

    We extend the concept of radially and azimuthally polarized optical beams to the polychromatic domain by introducing cylindrically polarized nondiffracting optical pulses. In particular, we discuss in detail the case of cylindrically polarized X-waves, both in the paraxial and nonparaxial regime. The explicit expressions for the electric and magnetic fields of cylindrically polarized X-waves are also reported.

  8. Static cylindrically symmetric spacetimes

    NASA Astrophysics Data System (ADS)

    Fjällborg, Mikael

    2007-05-01

    We prove the existence of static solutions to the cylindrically symmetric Einstein Vlasov system, and we show that the matter cylinder has finite extension in two of the three spatial dimensions. The same results are also proved for a quite general class of equations of state for perfect fluids coupled to the Einstein equations, extending the class of equations of state considered by Bicak et al (2004 Class. Quantum Grav.21 1583). We also obtain this result for the Vlasov Poisson system.

  9. [Automatic grinding of undecalcified bone sections with exact adjustment of thickness].

    PubMed

    Stürmer, K M

    1979-01-01

    A new grinding machine for preparing thin undecalcified bone sections after methylmethacrylate embedding is described. About 20 rather small bone sections can be ground at the same time; bigger specimens, up to 8 cm of length, are allowed. Bone sections are mounted on a cylindrical specimen holder by an adhesive film. Then the final thickness of the sections is exactly adjusted by screwing three rubies out of the holder's bottom. Now the prepared holder is set in a guide ring on a turntable carrying a rough ended glass plate. The desired thickness of the sections is reached as soon as the three rubies touch the glass surface. The variation in the thickness of the sections is less than +/- 3 micron. The machine is simply constructed, easily to handle and rapidly to clean. PMID:371325

  10. Chirality Change by Grinding Crystals in Solution

    SciTech Connect

    Viedma, Cristobal

    2010-07-22

    One of the greatest unsolved problems in chemistry is the origin of homochirality in the biosphere, that is, the fact that l-amino acids and d-sugars dominate in biology, while laboratory experiments with stereoselective reactions only produce racemic mixtures. Several models have been proposed to address the question of how enantiomerically pure solutions or crystalline phases could have emerged from a presumably racemic prebiotic world. Here we show that two populations of amino acid crystals of 'left' and 'right' hand cannot coexist in solution: one of the chiral populations disappears in an irreversible autocatalytic process that nurtures the other one. Final and complete chiral purity seems to be an inexorable fate in our systems, under grinding, in the course of the common process of growth-dissolution. This unexpected chiral symmetry breaking has become firmly established but the underlying mechanism is being debated and we have no definitive answer.

  11. Cylindrical optic figuring dwell time optimization

    NASA Astrophysics Data System (ADS)

    Waluschka, Eugene

    2000-11-01

    The Constellation-X, grazing incidence, x-ray telescope may be fabricated from replicated segments. A series of mandrels will serve as the 'masters' in the replication processes. Diamond turning (milling) followed by abrasive figuring followed by a super polishing are the steps currently envisioned in making just one (of many) mandrel. The abrasive figuring of a mandrel is accomplished by moving a grinding tool along a helical path on this almost cylindrical surface. The measurement of the surface is, however, performed along 'axial' scan lines which intercept this helical path. This approach to figuring and measuring permits a relatively simple scheme to be implemented for the determination of the optimal dwell times of the figuring tool. These optimal dwell times are determined by a deconvolution which approaches the problem in a linear programming context and uses the Simplex Method. The approach maximizes the amount of material removed at any point subject to inequality constraints. The effects of using these 'optimum' dwell times is to significantly improve the tools effectiveness at removing the higher spatial frequencies while staying (strictly) within the bounds and constraints imposed by the hardware. In addition, the ringing at the edges of the optic, frequently present in deconvolution problems, is completely eliminated.

  12. Technological Aspects of Forming the Surface Microrelief of Low-Wear Coatings after Electro-Diamond Grinding

    NASA Astrophysics Data System (ADS)

    Burov, V. G.; Yanpolskiy, V. V.; Rakhimyanov, K. Kh

    2016-04-01

    The results of electro-diamond grinding of coatings based on the WC25 powder material are presented in the paper. It is shown that after electro-diamond grinding of the WC25 coating, an obtained magnitude (Ra=2.02µm) of surface roughness doesn’t meet the qualifying standards to parts surface working in wear-out conditions. The forming of the obtained microrelief is probably connected to the features of electrochemical dissolution of the WC25 coating material in the electrolyte being used. Based on the polarization studies, it is revealed that the electrochemical dissolution character of the indicated coating in the water solution of 10%NaNO3 is determined by the dissolution character of cobalt (Co) component. The intensive cobalt (Co) dissolution during the electro-diamond grinding of the WC25 coating leads to the tungsten carbide chipping by the grinding disk particles that increases the roughness. One of the way to improve the surface quality of low-wear coatings after electro-diamond grinding is an introduction of an additional step in a technological process, carrying out with the switched off source of technological current. For realization of the process according to this scheme a technological dimension chain is made which takes into consideration the dissolution value of the most active coating composition element while the calculating of the operating dimensions of a detail.

  13. Conformal approach to cylindrical DLA

    NASA Astrophysics Data System (ADS)

    Taloni, A.; Caglioti, E.; Loreto, V.; Pietronero, L.

    2006-09-01

    We extend the conformal mapping approach elaborated for the radial diffusion limited aggregation model (DLA) to cylindrical geometry. We introduce in particular a complex function which allows a cylindrical cluster to be grown using as an intermediate step a radial aggregate. The aggregate grown exhibits the same self-affine features as the original cylindrical DLA. The specific choice of the transformation allows us to study the relationship between the radial and the cylindrical geometry. In particular the cylindrical aggregate can be seen as a radial aggregate with particles of size increasing with the radius. On the other hand, the radial aggregate can be seen as a cylindrical aggregate with particles of size decreasing with the height. This framework, which shifts the point of view from the geometry to the size of the particles, can open the way to more quantitative studies on the relationship between radial and cylindrical DLA.

  14. Ultrafine grinding of low-rank coal: Final report

    SciTech Connect

    Bouchillon, C.W.; Steele, W.G.

    1986-08-01

    A study of ultrafine grinding of low-rank coals in a fluid-energy mill was undertaken. This report presents the results of the Phase I effort which included a review of the literature on ultrafine grinding, a review of theories of grinding, a combined grinding and drying experiment on Martin Lake Texas lignite, an evaluation of the energy requirements for the process, and an evaluation of the properties of the products from the grinding tests. A sample of Martin Lake Texas lignite was obtained and a series of tests were conducted in a fluid-energy mill at the Ergon, Inc., Micro-Energy Division development facility at Vicksburg, MS. The grinding fluids used were air at 116 F and steam at 225, 310, 350, 400, and 488 F as measured in the mill. The products of these tests were analyzed for volatile mattr, ash, total moisture, equilibrium moisture, heating value, density distribution, aerodynamic particle size classification, angle of repose, porosity, density, and particle size distribution. ASTM test procedures were followed where applicable. Ultimate and ash mineral analyses were also conducted on the samples. Results of the various tests are presented in detail in the report. In general, the fluid energy mill was used succssfully in simultaneous grinding and drying of the lignite. Particle size reduction to less than 10 microns on a population basis was achieved. The equilibrium moisture of the samples decreased with increasing grinding fluid temperatures. Density distribution studies showed that a significant fraction of the ash appeared in the >1.6 specific gravity particles. The energy required for the grinding/drying process increased with increasing mill temperatures. 29 refs., 18 figs., 13 tabs.

  15. Cryogenic grinding technology for traditional Chinese herbal medicine

    NASA Astrophysics Data System (ADS)

    Li, Shimo; Ge, Shuangyan; Huang, Zhongping; Wang, Qun; Zhao, Haoping; Pan, Huaiyu

    The fundamental principle of cryogenic grinding (cryogrinding) for Chinese herbal medicine is similar to that of grinding methods for conventional materials, but the compositions are very complex, containing aromatics of high volatility, oils and fats, which are easily oxidized. Using liquid nitrogen or liquid air as the cryogen, all of these thermosensitive Chinese herbal medicines can be ground below their brittle temperature. The colour and other properties of the products of cryo-grinding will not be changed and the flavour and nutrition of the medicines will not be lost.

  16. Effect of wet grinding on structural properties of ball clay

    SciTech Connect

    Purohit, A. Chander, S.; Dhaka, M. S.; Hameed, A.; Singh, P.; Nehra, S. P.

    2015-05-15

    In this paper, the effect of wet grinding on structural properties of ball clay is undertaken. The wet grinding treatment was performed employing ball and vibro mills for different time spells of 2, 4, 8 and 16 hours. The structural properties were carried out using X-ray diffraction (XRD). The structure of ground samples is found to be simple cubic. The crystallographic parameters are calculated and slight change in lattice constant, inter planner spacing and particle size is observed with grinding treatment. The results are in agreement with the available literature.

  17. Grinding Wheel Condition Monitoring with Hidden Markov Model-Based Clustering Methods

    SciTech Connect

    Liao, T. W.; Hua, G; Qu, Jun; Blau, Peter Julian

    2006-01-01

    Hidden Markov model (HMM) is well known for sequence modeling and has been used for condition monitoring. However, HMM-based clustering methods are developed only recently. This article proposes a HMM-based clustering method for monitoring the condition of grinding wheel used in grinding operations. The proposed method first extract features from signals based on discrete wavelet decomposition using a moving window approach. It then generates a distance (dissimilarity) matrix using HMM. Based on this distance matrix several hierarchical and partitioning-based clustering algorithms are applied to obtain clustering results. The proposed methodology was tested with feature sequences extracted from acoustic emission signals. The results show that clustering accuracy is dependent upon cutting condition. Higher material removal rate seems to produce more discriminatory signals/features than lower material removal rate. The effect of window size, wavelet decomposition level, wavelet basis, clustering algorithm, and data normalization were also studied.

  18. Angular analysis of the cyclic impacting oscillations in a robotic grinding process

    NASA Astrophysics Data System (ADS)

    Rafieian, Farzad; Girardin, François; Liu, Zhaoheng; Thomas, Marc; Hazel, Bruce

    2014-02-01

    In a robotic machining process, a light-weight cutter or grinder is usually held by an articulated robot arm. Material removal is achieved by the rotating cutting tool while the robot end effector ensures that the tool follows a programmed trajectory in order to work on complex curved surfaces or to access hard-to-reach areas. One typical application of such process is maintenance and repair work on hydropower equipment. This paper presents an experimental study of the dynamic characteristics of material removal in robotic grinding, which is unlike conventional grinding due to the lower structural stiffness of the tool-holder robot. The objective of the study is to explore the cyclic nature of this mechanical operation to provide the basis for future development of better process control strategies. Grinding tasks that minimize the number of iterations to converge to the target surface can be better planned based on a good understanding and modeling of the cyclic material removal mechanism. A single degree of freedom dynamic analysis of the process suggests that material removal is performed through high-frequency impacts that mainly last for only a small fraction of the grinding disk rotation period. To detect these discrete cutting events in practice, a grinder is equipped with a rotary encoder. The encoder's signal is acquired through the angular sampling technique. A running cyclic synchronous average is applied to the speed signal to remove its non-cyclic events. The measured instantaneous rotational frequency clearly indicates the impacting nature of the process and captures the transient response excited by these cyclic impacts. The technique also locates the angular positions of cutting impacts in revolution cycles. It is thus possible to draw conclusions about the cyclic nature of dynamic changes in impact-cutting behavior when grinding with a flexible robot. The dynamics of the impacting regime and transient responses to impact-cutting excitations

  19. Grinding methods to enhance the reactivity of olivine

    SciTech Connect

    Summers, Cathy A.; Dahlin, David C.; Rush, Gilbert E.; O'Connor, William K.; Gerdemann, Stephen J.

    2005-08-01

    The Albany Research Center (ARC) conducted studies of mechanical activation by conventional and ultrafine grinding techniques to enhance olivine reactivity in mineral carbonation reactions. Activated olivine is one of several solid feed materials used at ARC in reactions with carbon dioxide to form carbonate minerals. This paper compares grinding techniques via energy demand data and product characteristics, including particle size distributions, surface areas, full-width-at-half-maximum (FWHM) XRD analyses, and particle morphology by SEM analyses. Reactivity was calculated by percent conversion to carbonate in subsequent carbonation tests. Particle size reduction has the greatest impact on reactivity, and wet grinding is more energy efficient than dry grinding. Large additional inputs of energy to increase surface area or reduce crystallinity do not result in proportional improvements in reactivity.

  20. DETAIL OF SPARE CONICAL CRUSHER AND GRINDING BURR WHEELS REMOVED ...

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

    DETAIL OF SPARE CONICAL CRUSHER AND GRINDING BURR WHEELS REMOVED FROM THE MILLING MACHINE. - F. & H. Benning Company Oyster Mill, 14430 Solomons Island Road (moved from 1014 Benning Road, Galesville, Anne Arundel County, Maryland), Solomons, Calvert County, MD

  1. 66. BUILDING NO. 554, REWORK POWDER GRINDING ROUSE, PULVERIZING, WATER ...

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

    66. BUILDING NO. 554, REWORK POWDER GRINDING ROUSE, PULVERIZING, WATER DRY HOUSE, LOOKING NORTH (DEMOLITION IN PROGRESS). - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  2. 41. PATTERN STORAGE, GRIND STONE, WATER TANK, SHAFTING, AND TABLE ...

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

    41. PATTERN STORAGE, GRIND STONE, WATER TANK, SHAFTING, AND TABLE SAW (L TO R)-LOOKING WEST. - W. A. Young & Sons Foundry & Machine Shop, On Water Street along Monongahela River, Rices Landing, Greene County, PA

  3. Measurement of cylindrical parts

    NASA Astrophysics Data System (ADS)

    Knight, Paul Douglas, Jr.

    The form of cylindrical parts has been traditionally evaluated using stylus-based mechanical instruments. The Tropel Corporation has developed a grazing incidence interferometer (GII) for the measurement of cylindrical parts. The repeatability of this instrument due to various instrument uncertainties was measured. Differing instrument configurations that produce the same systematic error were determined to produce a zonal calibration method for determining systematic error over the full range of the instrument, given knowledge of the error in a single zone. The effect of the aperture stop on the response of the imaging system to axially sinusoidal artifacts was simulated. Diamond-turned axially sinusoidal artifacts, with amplitude of order1 um and spatial wavelength of order10 mm, were measured to test the axial response of the interferometer. The modulation transfer function of the instrument's imaging system, measured using a knife edge test, predicts the response observed with the sinusoidal artifacts. A diffraction analysis predicts that the measured axial form is modified by a second order envelope function with phase that varies with the relative position of the imaging system focal plane and part position. A compensation method is proposed for this effect. A comparison of roundness measurements by both a traditional stylus-based instrument and the GII was performed demonstrating that the roundness measurements of the two instruments are equivalent when the measurements are properly corrected for the differing effects of surface finish.

  4. Cylindrical laser welder

    NASA Astrophysics Data System (ADS)

    Honeycutt, T. E.; Roberts, T. G.

    1986-05-01

    Brass retainer rings are currently fastened to artillery shells by spinning each shell at a high rate and then jamming the ring on it so that it is fastened or welded by friction between the two objects. This is an energy-inefficient process which heats and weakens more material than is desirable. The shell spinning at a high rate is also potentially dangerous. A laser welder is provided that generates output energy focused on a circular or cylindrical shape for simultaneously welding around a 360 degs circumference without unnecessarily heating large amounts of material. The welder may be used to fasten cylindrical shaped objects, gears and shafts together, which is difficult to do by conventional means. The welder may also be used to fasten one cylinder to another. To accomplish the welding, a laser has an unstable optical cavity arranged with its feedback mirror centered to generate a circular output beam having an obscuration in the center. A circularly-symmetric, off-axis concave mirror focuses the output beam onto the objects being fastened and away from the center line or axis of the circular beam.

  5. Cup Cylindrical Waveguide Antenna

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.; Darby, William G.; Kory, Carol L.; Lambert, Kevin M.; Breen, Daniel P.

    2008-01-01

    The cup cylindrical waveguide antenna (CCWA) is a short backfire microwave antenna capable of simultaneously supporting the transmission or reception of two distinct signals having opposite circular polarizations. Short backfire antennas are widely used in mobile/satellite communications, tracking, telemetry, and wireless local area networks because of their compactness and excellent radiation characteristics. A typical prior short backfire antenna contains a half-wavelength dipole excitation element for linear polarization or crossed half-wavelength dipole elements for circular polarization. In order to achieve simultaneous dual circular polarization, it would be necessary to integrate, into the antenna feed structure, a network of hybrid components, which would introduce significant losses. The CCWA embodies an alternate approach that entails relatively low losses and affords the additional advantage of compactness. The CCWA includes a circular cylindrical cup, a circular disk subreflector, and a circular waveguide that serves as the excitation element. The components that make it possible to obtain simultaneous dual circular polarization are integrated into the circular waveguide. These components are a sixpost polarizer and an orthomode transducer (OMT) with two orthogonal coaxial ports. The overall length of the OMT and polarizer (for the nominal middle design frequency of 2.25 GHz) is about 11 in. (approximately equal to 28 cm), whereas the length of a commercially available OMT and polarizer for the same frequency is about 32 in. (approximately equal to 81 cm).

  6. Lightweight Tool Grinds Back-Side Weld Beads

    NASA Technical Reports Server (NTRS)

    Gallagher, Robert L.

    1994-01-01

    Air-powered grinder enables high-quality rework of welds. Tool removes excess material from back side of weld in preparation for reworking. Used on workpiece while workpiece still mounted in welding fixture or welding machine. Then rewelded in original position, so full process control maintained. Used for grinding material in spaces to which access limited, such as in pressure vessels and in hulls of ships. Also used to grind materials other than metals.

  7. 65. BUILDING NO. 554, REWORK POWDER GRINDING HOUSE, PULVERIZING, WATER ...

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

    65. BUILDING NO. 554, REWORK POWDER GRINDING HOUSE, PULVERIZING, WATER DRY HOUSE, LOOKING SOUTH AT NORTH SIDE (DEMOLITION IN PROGRESS) OF BUILDING ONCE USED FOR REWORK POWDER GRINDING AND PULVERIZING (SEE NJ-36-C-33 FOR DIAGRAM OF THIS RECLAMATION PROCESS). THIS BUILDING ALSO SERVED AS A WATER DRY HOUSE. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  8. Surface grinding of space materials using specially formulated vitrified grinding wheels

    NASA Astrophysics Data System (ADS)

    Jackson, M. J.; Robinson, G.

    2006-04-01

    The quantum leap that is expected in the reliability and safety of machined engineering components over the next 20 years, especially in the space industries, will require improvements in the quality of cutting tools if science-based manufacturing is the goal for manufacturing by 2020. Significant improvements have been made in the past 10 years by understanding the properties of vitrified bonding systems used to bond conventional and superabrasive materials in grinding tools. The nature of the bonding system is of paramount importance if next-generation cutting tools are to be used for aerospace materials, especially if they are dressed using laser beams.

  9. Grinding aspheric and freeform micro-optical molds

    NASA Astrophysics Data System (ADS)

    Tohme, Yazid E.

    2007-02-01

    Fueled by the need for better performing optics, glass optics are now replacing plastic optics in many industrial and consumer electronic devices. One of these devices is the mobile phone camera. The optical sub-assembly in a mobile phone includes several micro lenses that are spherical and/or aspherical in shape and require form tolerances in the submicron range. These micro glass lenses are mass produced by a replication process known as glass press molding. The process entails the compression of a glass gob between two precise optical quality molds at an elevated temperature, usually near the transition temperature of the glass material. The elevated forces and temperatures required in the glass molding process limits the materials of the molds to very tough materials such as tungsten carbide or silicon carbide. These materials can withstand large pressing forces at high temperatures without any significant deformation. These materials offer great mechanical properties for glass press molding but they are also a challenge to machine to submicron accuracy. The work in this paper discusses a deterministic micro grinding manufacturing process referred to as wheel normal grinding, which is utilized to produce these optical quality molds. Wheel normal grinding is more accurate and more deterministic than most other grinding techniques and can produce molds to the form and finish tolerances required for optical molding. This method relies on the ability to recognize and compensate for grinding wheel wear and machine repeatable errors. Results will be presented to illustrate the accuracy of this micro grinding technique.

  10. A printed circuit cylindrical array antenna

    NASA Astrophysics Data System (ADS)

    Agrawal, Ashok K.; Powell, Walter E.

    1986-11-01

    The design and performance of a Ku-band cylindrical antenna are described. The antenna is designed to provide a 360-deg azimuth coverage with 20-dB sidelobes and an operating bandwidth of 1 GHz (16.0-17.0 GHz). The antenna consists of 16 facets of 2 x 4 dipole arrays. The 360-deg coverage is obtained with a switch matrix network. The antenna elements and the feeding switch matrix network are printed on a single printed circuit board.

  11. Identification and control of grinding processes for intermetallic compounds

    NASA Astrophysics Data System (ADS)

    Razavi, Hosein Ali

    2000-10-01

    An intermetallic compound (IMC) is a combination of two or more metals with a particular atomic formula by having either ionic and covalent bonds, or metallic bonds with specific crystal structures. They may be thought of as the intermediate between metals and ceramics. These new materials may combine the best of each class: the ductility, heat and electric conductivity of metals with the strength and oxidation resistance of ceramics. Previous study has proposed that the depth of plastic deformation can be used as a parameter to describe the influence of grinding conditions on other physical properties of subsurface layers. Accordingly, the indentation model has been developed to correlate the depth of plastic deformation with the normal component of grinding force. It has been reported that the under certain grinding conditions the depth of plastic deformation does not follow the indentation model. The primary objective of this research is to explain such deviations and to demonstrate that this model can be used to control and predict the depth of plastic deformation. Elements of this research include the development of an open architecture platform to study grinding process, a signal processing algorithm for gap elimination, introducing and implementation of model reference unfalsification and learning concept, development of a mathematical model for grinding gamma-TiAl, a comparison between conventional and superabrasive grinding, control and prediction of the depth of plastic deformation, and initiation of one of the first databases for grinding gamma-TiAl. This work not only serves as a step toward the use of IMCs in future technology but also serves as a step toward autonomous machining systems using intelligent control and advanced monitoring which is a feature of the future abrasive technology.

  12. Stage Cylindrical Immersive Display

    NASA Technical Reports Server (NTRS)

    Abramyan, Lucy; Norris, Jeffrey S.; Powell, Mark W.; Mittman, David S.; Shams, Khawaja S.

    2011-01-01

    Panoramic images with a wide field of view intend to provide a better understanding of an environment by placing objects of the environment on one seamless image. However, understanding the sizes and relative positions of the objects in a panorama is not intuitive and prone to errors because the field of view is unnatural to human perception. Scientists are often faced with the difficult task of interpreting the sizes and relative positions of objects in an environment when viewing an image of the environment on computer monitors or prints. A panorama can display an object that appears to be to the right of the viewer when it is, in fact, behind the viewer. This misinterpretation can be very costly, especially when the environment is remote and/or only accessible by unmanned vehicles. A 270 cylindrical display has been developed that surrounds the viewer with carefully calibrated panoramic imagery that correctly engages their natural kinesthetic senses and provides a more accurate awareness of the environment. The cylindrical immersive display offers a more natural window to the environment than a standard cubic CAVE (Cave Automatic Virtual Environment), and the geometry allows multiple collocated users to simultaneously view data and share important decision-making tasks. A CAVE is an immersive virtual reality environment that allows one or more users to absorb themselves in a virtual environment. A common CAVE setup is a room-sized cube where the cube sides act as projection planes. By nature, all cubic CAVEs face a problem with edge matching at edges and corners of the display. Modern immersive displays have found ways to minimize seams by creating very tight edges, and rely on the user to ignore the seam. One significant deficiency of flat-walled CAVEs is that the sense of orientation and perspective within the scene is broken across adjacent walls. On any single wall, parallel lines properly converge at their vanishing point as they should, and the sense of

  13. Low-Rank Coal Grinding Performance Versus Power Plant Performance

    SciTech Connect

    Rajive Ganguli; Sukumar Bandopadhyay

    2008-12-31

    The intent of this project was to demonstrate that Alaskan low-rank coal, which is high in volatile content, need not be ground as fine as bituminous coal (typically low in volatile content) for optimum combustion in power plants. The grind or particle size distribution (PSD), which is quantified by percentage of pulverized coal passing 74 microns (200 mesh), affects the pulverizer throughput in power plants. The finer the grind, the lower the throughput. For a power plant to maintain combustion levels, throughput needs to be high. The problem of particle size is compounded for Alaskan coal since it has a low Hardgrove grindability index (HGI); that is, it is difficult to grind. If the thesis of this project is demonstrated, then Alaskan coal need not be ground to the industry standard, thereby alleviating somewhat the low HGI issue (and, hopefully, furthering the salability of Alaskan coal). This project studied the relationship between PSD and power plant efficiency, emissions, and mill power consumption for low-rank high-volatile-content Alaskan coal. The emissions studied were CO, CO{sub 2}, NO{sub x}, SO{sub 2}, and Hg (only two tests). The tested PSD range was 42 to 81 percent passing 76 microns. Within the tested range, there was very little correlation between PSD and power plant efficiency, CO, NO{sub x}, and SO{sub 2}. Hg emissions were very low and, therefore, did not allow comparison between grind sizes. Mill power consumption was lower for coarser grinds.

  14. New optical cylindrical microresonators

    NASA Astrophysics Data System (ADS)

    Gun'ko, Yurii K.; Balakrishnan, Sivakumar; McCarthy, Joseph E.; Rakovich, Yuri P.; Donegan, John F.; Perova, Tatiana S.; Melnikov, Vasily

    2007-10-01

    In this paper we describe a novel technique for the fabrication of aluminosilicate microfibres and microtubes which are shown to act as optical cylindrical microresonators. The alumosilicate microfibres and microtubes were fabricated by using vacuum-assisted wetting and filtration of silica gel through a microchannel glass matrix. The microfibres and microtubes were studied using Scanning Electron Microscopy (SEM), micro-photoluminescence spectroscopy and fluorescence lifetime imaging confocal microscopy. In the emission spectra of the micro-resonators we find very narrow periodic peaks corresponding to the whispering gallery modes of two orthogonal polarizations with quality factors up to 3200. A strong enhancement in photoluminescence decay rates at high excitation power demonstrates the occurrence of amplified spontaneous emission from a single microtube. These microtubes show a large evanescent field extending many microns beyond the tube radius. Potential applications for these novel microresonators will be in the area of optical microsensors for a single molecule detection of biological and chemical species, including anti-terrorism and defense sectors.

  15. Shearfree cylindrical gravitational collapse

    SciTech Connect

    Di Prisco, A.; Herrera, L.; MacCallum, M. A. H.; Santos, N. O.

    2009-09-15

    We consider diagonal cylindrically symmetric metrics, with an interior representing a general nonrotating fluid with anisotropic pressures. An exterior vacuum Einstein-Rosen spacetime is matched to this using Darmois matching conditions. We show that the matching conditions can be explicitly solved for the boundary values of metric components and their derivatives, either for the interior or exterior. Specializing to shearfree interiors, a static exterior can only be matched to a static interior, and the evolution in the nonstatic case is found to be given in general by an elliptic function of time. For a collapsing shearfree isotropic fluid, only a Robertson-Walker dust interior is possible, and we show that all such cases were included in Cocke's discussion. For these metrics, Nolan and Nolan have shown that the matching breaks down before collapse is complete, and Tod and Mena have shown that the spacetime is not asymptotically flat in the sense of Berger, Chrusciel, and Moncrief. The issues about energy that then arise are revisited, and it is shown that the exterior is not in an intrinsic gravitational or superenergy radiative state at the boundary.

  16. Evaluation of ball and roller bearings restored by grinding

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Zaretsky, E. V.; Chen, S. M.

    1976-01-01

    The restoration by grinding of those rolling element bearings which are currently being discarded at aircaft engine and transmission overhaul is considered. Three bearing types were selected from the UH-1 helicopter engine and transmission for the pilot program. Groups of each of these bearings were visually and dimensionally inspected for suitability for restoration. A total of 250 bearings were restored by grinding. Of this number, 30 bearings from each type were endurance tested to a TBO of 1600 hours. No bearing failures occurred related to the restoration by grinding process. The two bearing failures which occurred were due to defective rolling elements and were typical of those which may occur in new bearings. The restorable component yield to the three groups was in excess of 90 percent.

  17. Evaluation of ball and roller bearings restored by grinding

    NASA Technical Reports Server (NTRS)

    Parker, R. J.; Zaretsky, E. V.; Chen, S. M.

    1976-01-01

    A joint program was undertaken to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. Groups of each of these bearings were visually and dimensionally inspected for suitability for restoration. A total of 250 bearings were restored by grinding. Of this number, 30 bearings from each type were endurance tested to a TBO of 1600 hours. No bearing failures occurred related to the restoration by grinding process. The two bearing failures which occurred were due to defective rolling elements and were typical of those which may occur in new bearings. The restorable component yield to the three groups was in excess of 90 percent.

  18. Surface tension and long range corrections of cylindrical interfaces

    SciTech Connect

    Bourasseau, E.; Ghoufi, A.

    2015-12-21

    The calculation of the surface tension of curved interfaces has been deeply investigated from molecular simulation during this last past decade. Recently, the thermodynamic Test-Area (TA) approach has been extended to the calculation of surface tension of curved interfaces. In the case of the cylindrical vapour-liquid interfaces of water and Lennard-Jones fluids, it was shown that the surface tension was independent of the curvature of the interface. In addition, the surface tension of the cylindrical interface is higher than that of the planar interface. Molecular simulations of cylindrical interfaces have been so far performed (i) by using a shifted potential, (ii) by means of large cutoff without periodic boundary conditions, or (iii) by ignoring the long range corrections to the surface tension due to the difficulty to estimate them. Indeed, unlike the planar interfaces there are no available operational expressions to consider the tail corrections to the surface tension of cylindrical interfaces. We propose here to develop the long range corrections of the surface tension for cylindrical interfaces by using the non-exponential TA (TA2) method. We also extend the formulation of the Mecke-Winkelmann corrections initially developed for planar surfaces to cylindrical interfaces. We complete this study by the calculation of the surface tension of cylindrical surfaces of liquid tin and copper using the embedded atom model potentials.

  19. Cylindrical Projection of Jupiter

    NASA Technical Reports Server (NTRS)

    1979-01-01

    This computer generated map of Jupiter was made from 10 color images of Jupiter taken Feb. 1, 1979, by Voyager 1, during a single, 10 hour rotation of the planet. Computers at Jet Propulsion Laboratory's Image Processing Lab then turned the photos into this cylindrical projection. Such a projection is invaluable as an instantaneous view of the entire planet. Along the northern edge of the north equatorial belt (NEB) are four dark brown, oblong regions believed by some scientists to be openings in the more colorful upper cloud decks, allowing the darker clouds beneath to be seen. The broad equatorial zone (EZ) is dominated by a series of plumes, possibly regions of intense convective activity, encircling the entire planet. In the southern hemisphere the Great Red Spot is located at about 75 degrees longitude. South of the Great Red Spot in the south temperate zone (STeZ) three large white ovals, seen from Earth-based observatories for the past few decades, are located at 5 degrees, 85 degrees and 170 degrees longitude. Resolution in this map is 375 miles (600 kilometers). Since Jupiter's atmospheric features drift around the planet, longitude is based on the orientation of the planet's magnetic field. Symbols at right edge of photo denote major atmospheric features (dark belts and light zones): NTeZ - north temperate zone; NTrZ - north tropical zone; NEB - north equatorial belt; EZ - equatorial zone; SEB - south equatorial belt; STrZ - south tropical zone; and STeZ - south temperate zone. Voyager belt; EZ - equatorial zone; SEB - south tropical zone; Voyager is managed for NASA's Office of Space Science by Jet Propulsion Laboratory.

  20. Grinding methods to enhance the reactivity of olivine

    SciTech Connect

    Summers, Cathy A.; Dahlin, David C.; Rush, Gilbert E.; O'Connor, William K.; Gerdemann, Stephen J.

    2004-01-01

    The Albany Research Center (ARC) conducted studies of mechanical activation by conventional and ultra-fine grinding techniques to enhance olivine reactivity in mineral carbonation reactions. Activated olivine is one of several solid feed materials used at ARC in reactions with carbon dioxide to form carbonate minerals. This paper compares grinding techniques via energy demand data and product characteristics, including particle size distributions, surface areas, full width at half maximum (FWHM) XRD analyses, and particle morphology by SEM analyses. Reactivity was gauged by percent conversion to carbonate in subsequent carbonation tests.

  1. Energy efficiency of cement finish grinding in a dry batch ball mill

    SciTech Connect

    Touil, D.; Belaadi, S.; Frances, C. . E-mail: Christine.Frances@ensiacet.fr

    2006-03-15

    Dry grinding experiments on cement clinker were carried out using a laboratory batch ball mill equipped with torque measurement. The specific energy was found to be dependent on operating parameters and clinker environment. Additional compounds such as gypsum and pozzolanic tuff improve energy efficiency. The optimal parameters allowing maximising the energy efficiency factor were determined. Energy efficiency factors were obtained both on the crude material (size minus 2.8 mm) and on a sieved fraction (1-0.71 mm). They demonstrate that a low initial rate of breakage implies higher energy efficiency. On the contrary, conditions ensuring an initial maximal rate of breakage lead to an increase of the energy consumption.

  2. Effect of SAR on human head modeling inside cylindrical enclosures.

    PubMed

    Mary, T Anita Jones; Ravichandran, C S

    2013-09-01

    This study intends to discuss enclosed a realistic approach to determine and analyze the effects of radio frequency on human exposure inside a cylindrical enclosure. A scenario in which a mobile phone with inverted-F antenna (IFA) operating in the Global System for Mobile Communication (GSM) band (900 MHz) is used inside a cylindrical enclosure. Metallic enclosures are known to have resonance and reflection effects, thereby increasing electric field strength and hence resulting in a change of the human exposure to electromagnetic absorptions. So, this study examines and compares the levels of absorption in terms of specific absorption rate (SAR) values under various conditions. In this study, a human phantom with dielectric properties is designed and its interaction is studied with IFA inside fully enclosed cylindrical enclosures. The results show that SAR values are increased inside cylindrical enclosures compared with those in free space. The method of computation uses method of moments. Simulations are done in FEKO software. PMID:23323517

  3. Pulsed Laser Profiling of Grinding Wheels at Normal and Quasi-Tangential Incidence

    NASA Astrophysics Data System (ADS)

    Lutey, Adrian H. A.; Fortunato, Alessandro; Zanini, Filippo; Carmignato, Simone

    2016-06-01

    A new methodology for normal and quasi-tangential pulsed laser profiling of grinding wheels is proposed, with laser path planning calculated according to a pre-specified angle of incidence and radial laser progression or predicted single-pass incision depth. Though tangential laser profiling has previously been investigated, few works have addressed the issue of negligible laser absorption under these conditions other than to apply a focal offset that effectively reduces the angle of incidence below 90∘. In the present work, the angle of incidence is specified explicitly, with normal and quasi-tangential profiling experiments performed on rotating bronze-bonded diamond and porous aluminum oxide grinding wheels with a 1064 nm nanosecond pulsed fiber laser source with 20 W average power. Triangular incisions are cut into each sample, following which analyses are performed with an optical profiler operating in confocal mode and x-ray computed tomography to determine the material removal rate and profile accuracy under all tested conditions. The angle of laser incidence is found to be of particular relevance to profiling operations, with more than one order of magnitude difference in material removal rates observed between 70∘ and 80∘ incidence, with improved profile accuracy in the latter case. Specifically, material removal rates of 0.12-0.14 mm 3/s, 0.075-0.1 mm 3/s and 0.002 mm 3/s are achieved at normal, 70∘ and 80∘ laser incidence, respectively, for bronze-bonded diamond, and 0.1 mm 3/s is achieved at 70∘ incidence for porous aluminum oxide. For both materials, profile accuracy of 50-70 μm is achieved under optimum conditions. The presented results highlight the necessity for precise specification and control of the angle of incidence during laser profiling operations. They furthermore confirm that laser profiling of grinding wheels is a viable alternative to electrical discharge machining for bronze-bonded diamond grinding wheels and a potential

  4. Pulsed Laser Profiling of Grinding Wheels at Normal and Quasi-Tangential Incidence

    NASA Astrophysics Data System (ADS)

    Lutey, Adrian H. A.; Fortunato, Alessandro; Zanini, Filippo; Carmignato, Simone

    2016-09-01

    A new methodology for normal and quasi-tangential pulsed laser profiling of grinding wheels is proposed, with laser path planning calculated according to a pre-specified angle of incidence and radial laser progression or predicted single-pass incision depth. Though tangential laser profiling has previously been investigated, few works have addressed the issue of negligible laser absorption under these conditions other than to apply a focal offset that effectively reduces the angle of incidence below 90∘. In the present work, the angle of incidence is specified explicitly, with normal and quasi-tangential profiling experiments performed on rotating bronze-bonded diamond and porous aluminum oxide grinding wheels with a 1064 nm nanosecond pulsed fiber laser source with 20 W average power. Triangular incisions are cut into each sample, following which analyses are performed with an optical profiler operating in confocal mode and x-ray computed tomography to determine the material removal rate and profile accuracy under all tested conditions. The angle of laser incidence is found to be of particular relevance to profiling operations, with more than one order of magnitude difference in material removal rates observed between 70∘ and 80∘ incidence, with improved profile accuracy in the latter case. Specifically, material removal rates of 0.12-0.14 mm 3/ s, 0.075-0.1 mm 3/ s and 0.002 mm 3/ s are achieved at normal, 70∘ and 80∘ laser incidence, respectively, for bronze-bonded diamond, and 0.1 mm 3/ s is achieved at 70∘ incidence for porous aluminum oxide. For both materials, profile accuracy of 50-70 μm is achieved under optimum conditions. The presented results highlight the necessity for precise specification and control of the angle of incidence during laser profiling operations. They furthermore confirm that laser profiling of grinding wheels is a viable alternative to electrical discharge machining for bronze-bonded diamond grinding wheels and a potential

  5. Recovery of titanium values from titanium grinding swarf by electric furnace smelting

    DOEpatents

    Gerdemann, S.J.; White, J.C.

    1998-08-04

    A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag. 1 fig.

  6. Recovery of titanium values from titanium grinding swarf by electric furnace smelting

    DOEpatents

    Gerdemann, Stephen J.; White, Jack C.

    1999-01-01

    A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag.

  7. Recovery of titanium values from titanium grinding swarf by electric furnace smelting

    DOEpatents

    Gerdemann, Stephen J.; White, Jack C.

    1998-01-01

    A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag.

  8. Recovery of titanium values from titanium grinding swarf by electric furnace smelting

    SciTech Connect

    Gerdemann, S.J.; White, J.C.

    1999-10-19

    A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag.

  9. Grinding Kinetics of Vanadium-Titanium Magnetite Concentrate in a Damp Mill and Its Properties

    NASA Astrophysics Data System (ADS)

    Long, Hongming; Chun, Tiejun; Wang, Ping; Meng, Qingmin; Di, Zhanxia; Li, Jiaxin

    2016-06-01

    The grinding behavior of the as-received (5 pct moisture) vanadium-titanium magnetite concentrates in a damp mill was investigated in this paper. A grinding kinetics equation was established based on a population balance model using size distribution data obtained from a laser diffraction technique. X-ray diffraction results show that a loss in crystallinity occurs when the grinding time is increased. The crystallite size of the materials decreased, whereas their structural microstrain increased with increasing grinding time. The wettability increased because the surface roughness increases with increasing grinding time. The moisture capacity of the solids increased during the first 3 minutes of grinding and then remained roughly constant with further increases in grinding time. The water transfer coefficient of the particles increased at grinding times of 3 and 6 minutes and then decreased at grinding times of 9 and 12 minutes. The compressive strength of oxidized pellets increased with increasing grinding time; longer grinding times can compensate for the effects of lower roasting temperature or shorter roasting time on the strength of the pellets. Lowering the roasting temperature and shortening the roasting time by grinding appeared to be possible.

  10. GRINDING ROOM, LOOKING EAST. NOTE OVERHEAD BRIDGE CRANE RIDING ON ...

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

    GRINDING ROOM, LOOKING EAST. NOTE OVERHEAD BRIDGE CRANE RIDING ON STEEL RAILS SUPPORTED BY WOODEN BEAMS AND CYCLONE CLASSIFIER IN CENTER. AT RIGHT IS TOP PORTION OF FLASH FLOTATION CELL. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

  11. 30 CFR 77.401 - Stationary grinding machines; protective devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... devices. 77.401 Section 77.401 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF...; protective devices. (a) Stationary grinding machines other than special bit grinders shall be equipped with: (1) Peripheral hoods (less than 90° throat openings) capable of withstanding the force of a...

  12. 30 CFR 77.401 - Stationary grinding machines; protective devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... devices. 77.401 Section 77.401 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF...; protective devices. (a) Stationary grinding machines other than special bit grinders shall be equipped with: (1) Peripheral hoods (less than 90° throat openings) capable of withstanding the force of a...

  13. INTERIOR VIEW WITH GRINDING MILL AND CONVEYOR EXTENDING UP TO ...

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

    INTERIOR VIEW WITH GRINDING MILL AND CONVEYOR EXTENDING UP TO SORTING DRUM. DRIVE ENGINE AT LOWER LEFT. RADIATOR FOR ENGINE AT RIGHT. - F. & H. Benning Company Oyster Mill, 14430 Solomons Island Road (moved from 1014 Benning Road, Galesville, Anne Arundel County, Maryland), Solomons, Calvert County, MD

  14. VIEW, LOOKING WEST TOWARD GRINDING AREA, OF MAINTENCE SHOP. NOTE ...

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

    VIEW, LOOKING WEST TOWARD GRINDING AREA, OF MAINTENCE SHOP. NOTE TRACK IN FLOOR FOR CARTS WITH HEAVY ITEMS, OVERHEAD JIB CRANE AT UPPER RIGHT, PARTIALLY OBSCURED "SG" LOGO ON CABINET, AND SIGNS ABOVE DOORWAY TO MILL. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

  15. Computer numerical control grinding of spiral bevel gears

    NASA Technical Reports Server (NTRS)

    Scott, H. Wayne

    1991-01-01

    The development of Computer Numerical Control (CNC) spiral bevel gear grinding has paved the way for major improvement in the production of precision spiral bevel gears. The object of the program was to decrease the setup, maintenance of setup, and pattern development time by 50 percent of the time required on conventional spiral bevel gear grinders. Details of the process are explained.

  16. Multisurface fixture permits easy grinding of tool bit angles

    NASA Technical Reports Server (NTRS)

    Jones, C. R.

    1966-01-01

    Multisurface fixture with a tool holder permits accurate grinding and finishing of right and left hand single point threading tools. All angles are ground by changing the fixture position to rest at various references angles without removing the tool from the holder.

  17. Enhanced Performance of Cylindrical Hall Thrusters

    SciTech Connect

    Y. Raitses, A. Smirnov, and N.J. Fisch

    2007-05-14

    The cylindrical thruster differs significantly in its underlying physical mechanisms from the conventional annular Hall thruster. It features high ionization efficiency, quiet operation, ion acceleration in a large volume-to-surface ratio channel, and performance comparable with the state-of-the-art conventional Hall thrusters. Very significant plume narrowing, accompanied by the increase of the energetic ion fraction and improvement of ion focusing, led to 50%–60% increase of the thruster anode efficiency. These improvements were achieved by overrunning the discharge current in the magnetized thruster plasma.

  18. Enhanced performance of cylindrical Hall thrusters

    SciTech Connect

    Raitses, Y.; Smirnov, A.; Fisch, N. J.

    2007-05-28

    The cylindrical thruster differs significantly in its underlying physical mechanisms from the conventional annular Hall thruster. It features high ionization efficiency, quiet operation, ion acceleration in a large volume-to-surface ratio channel, and performance comparable with the state-of-the-art conventional Hall thrusters. Very significant plume narrowing, accompanied by the increase of the energetic ion fraction and improvement of ion focusing, led to 50%-60% increase of the thruster anode efficiency. These improvements were achieved by overrunning the discharge current in the magnetized thruster plasma.

  19. Development of an intelligent grinding wheel for in-process monitoring of ceramic grinding. Semi-annual report {number_sign}3

    SciTech Connect

    Malkin, S.; Gao, R.; Guo, C.; Varghese, B.; Pathare, S.

    1998-03-26

    This is the third semi-annual report for the project. The overall objective of this project is to develop sensor-integrated intelligent diamond wheels for grinding of ceramics. Such wheels will be smart enough to monitor and supervise both the wheel preparation and grinding processes without the need to instrument the machine tool. Intelligent wheels will utilize re-useable cores integrated with sensors: to measure the acoustic emission (AE) and grinding force. Signals from the sensors will be transmitted from a rotating wheel to a receiver by telemetry. Wheels will be trained to recognize distinct characteristics associated with truing, dressing and grinding. The technical progress is summarized in this report.

  20. Subsurface mechanical damage during bound abrasive grinding of fused silica glass

    NASA Astrophysics Data System (ADS)

    Blaineau, P.; André, D.; Laheurte, R.; Darnis, P.; Darbois, N.; Cahuc, O.; Neauport, J.

    2015-10-01

    The subsurface damage (SSD) introduced during bound abrasive grinding of fused silica glass was measured using a wet etch technique. Various process parameters and grinding configurations were studied. The relation between the SSD depth, the process parameters and forces applied by the grinding wheel on the sample was investigated and compared to a simulation using a discrete element method to model the grinding interface. The results reveal a relation between the SSD depth and the grinding forces normalized by the abrasive concentration. Regarding the creation of the SSD, numerical simulations indicate that only a small fraction of the largest particles in the diamond wheel are responsible for the depth of the damaged layer.

  1. Cylindrical acoustic levitator/concentrator

    DOEpatents

    Kaduchak, Gregory; Sinha, Dipen N.

    2002-01-01

    A low-power, inexpensive acoustic apparatus for levitation and/or concentration of aerosols and small liquid/solid samples having particulates up to several millimeters in diameter in air or other fluids is described. It is constructed from a commercially available, hollow cylindrical piezoelectric crystal which has been modified to tune the resonance frequency of the breathing mode resonance of the crystal to that of the interior cavity of the cylinder. When the resonance frequency of the interior cylindrical cavity is matched to the breathing mode resonance of the cylindrical piezoelectric transducer, the acoustic efficiency for establishing a standing wave pattern in the cavity is high. The cylinder does not require accurate alignment of a resonant cavity. Water droplets having diameters greater than 1 mm have been levitated against the force of gravity using; less than 1 W of input electrical power. Concentration of aerosol particles in air is also demonstrated.

  2. Development of a grinding-specific performance test set-up.

    PubMed

    Olesen, C G; Larsen, B H; Andresen, E L; de Zee, M

    2015-01-01

    The aim of this study was to develop a performance test set-up for America's Cup grinders. The test set-up had to mimic the on-boat grinding activity and be capable of collecting data for analysis and evaluation of grinding performance. This study included a literature-based analysis of grinding demands and a test protocol developed to accommodate the necessary physiological loads. This study resulted in a test protocol consisting of 10 intervals of 20 revolutions each interspersed with active resting periods of 50 s. The 20 revolutions are a combination of both forward and backward grinding and an exponentially rising resistance. A custom-made grinding ergometer was developed with computer-controlled resistance and capable of collecting data during the test. The data collected can be used to find measures of grinding performance such as peak power, time to complete and the decline in repeated grinding performance. PMID:25367077

  3. Fatigue limit of polycrystalline zirconium oxide ceramics: Effect of grinding and low-temperature aging.

    PubMed

    Pereira, G K R; Silvestri, T; Amaral, M; Rippe, M P; Kleverlaan, C J; Valandro, L F

    2016-08-01

    The following study aimed to evaluate the effect of grinding and low-temperature aging on the fatigue limit of Y-TZP ceramics for frameworks and monolithic restorations. Disc specimens from each ceramic material, Lava Frame (3M ESPE) and Zirlux FC (Ivoclar Vivadent) were manufactured according to ISO:6872-2008 and assigned in accordance with two factors: (1) "surface treatment"-without treatment (as-sintered, Ctrl), grinding with coarse diamond bur (181µm; Grinding); and (2) "low-temperature aging (LTD)" - presence and absence. Grinding was performed using a contra-angle handpiece under constant water-cooling. LTD was simulated in an autoclave at 134°C under 2-bar pressure for 20h. Mean flexural fatigue limits (20,000 cycles) were determined under sinusoidal loading using stair case approach. For Lava ceramic, it was observed a statistical increase after grinding procedure and different behavior after LTD stimuli (Ctrl<Grinding; CtrlGrinding=Grinding Ltd); while for Zirlux, grinding and low-temperature aging promoted a statistical increase in the fatigue limit (Ctrl<Grinding; CtrlGrinding Ltd). An important increase was observed in m-phase content after both stimuli (grinding and LTD), although with different intensities. Additionally, fatigue test did not promote increase of m-phase content. Thus, tested grinding and low temperature aging did not damage the fatigue limit values significantly for both materials evaluated, even though those conditions promoted increase in m-phase. PMID:26828768

  4. Telescoping cylindrical piezoelectric fiber composite actuator assemblies

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor); Fox, legal representative, Christopher L. (Inventor); Fox Chattin, legal representative, Melanie L. (Inventor)

    2010-01-01

    A telescoping actuator assembly includes a plurality of cylindrical actuators in a concentric arrangement. Each cylindrical actuator is at least one piezoelectric fiber composite actuator having a plurality of piezoelectric fibers extending parallel to one another and to the concentric arrangement's longitudinal axis. Each cylindrical actuator is coupled to concentrically-adjacent ones of the cylindrical actuators such that the plurality of cylindrical actuators can experience telescopic movement. An electrical energy source coupled to the cylindrical actuators applies actuation energy thereto to generate the telescopic movement.

  5. JKR adhesion in cylindrical contacts

    NASA Astrophysics Data System (ADS)

    Sundaram, Narayan; Farris, T. N.; Chandrasekar, S.

    2012-01-01

    Planar JKR adhesive solutions use the half-plane assumption and do not permit calculation of indenter approach or visualization of adhesive force-displacement curves unless the contact is periodic. By considering a conforming cylindrical contact and using an arc crack analogy, we obtain closed-form indenter approach and load-contact size relations for a planar adhesive problem. The contact pressure distribution is also obtained in closed-form. The solutions reduce to known cases in both the adhesion-free and small-contact solution ( Barquins, 1988) limits. The cylindrical system shows two distinct regimes of adhesive behavior; in particular, contact sizes exceeding the critical (maximum) size seen in adhesionless contacts are possible. The effects of contact confinement on adhesive behavior are investigated. Some special cases are considered, including contact with an initial neat-fit and the detachment of a rubbery cylinder from a rigid cradle. A comparison of the cylindrical solution with the half-plane adhesive solution is carried out, and it indicates that the latter typically underestimates the adherence force. The cylindrical adhesive system is novel in that it possesses stable contact states that may not be attained even on applying an infinite load in the absence of adhesion.

  6. Optics Demonstrations Using Cylindrical Lenses

    ERIC Educational Resources Information Center

    Ivanov, Dragia; Nikolov, Stefan

    2015-01-01

    In this paper we consider the main properties of cylindrical lenses and propose several demonstrational experiments that can be performed with them. Specifically we use simple glasses full of water to demonstrate some basic geometrical optics principles and phenomena. We also present some less standard experiments that can be performed with such…

  7. Vibration of perforated cylindrical shells

    NASA Astrophysics Data System (ADS)

    Cousseau, Peter L.

    For a credible design of an inertial confinement fusion (ICF) target chamber, the vibration characteristics of the chamber must be completely understood. Target chambers are usually cylindrical or spherical in shape and contain hundreds of perforations (called ports) to allow access to the inside of the chamber. The fusion reaction within the chamber creates a uniform impulsive loading, which the chamber walls must be designed to contain. Also prior to an implosion, a delicate alignment process of the drivers and diagnostics takes place. The vibration of the chamber from rotating machinery, e.g., vacuum pumps, and ambient sources must be completely understood and accounted for during these alignment procedures. This dissertation examines the vibration characteristics of perforated cylindrical shells. Because the target chambers' thickness-to-radius ratio is small, such chambers can be modeled as thin shells. Included in the text is a literature review of perforated plates and shells and examples of the use of perforated structures in constructed and proposed ICF target chambers. The natural frequencies and corresponding mode shapes of perforated and unperforated cylindrical shells are studied analytically, numerically (via finite elements) and experimentally. Conclusions and comparisons between the different solution methods are made for both the perforated and unperforated cases. In addition, the dynamic response of perforated cylindrical shells to an axisymmetric impulsive loading has been identified. A demonstration showing how the convolution integral can be used to determine the response of a cylinder to a non-impulsive loading is presented.

  8. New Geometry of Worm Face Gear Drives with Conical and Cylindrical Worms: Generation, Simulation of Meshing, and Stress Analysis

    NASA Technical Reports Server (NTRS)

    Litvin, Faydor L.; Nava, Alessandro; Fan, Qi; Fuentes, Alfonso

    2002-01-01

    New geometry of face worm gear drives with conical and cylindrical worms is proposed. The generation of the face worm-gear is based on application of a tilted head-cutter (grinding tool) instead of application of a hob applied at present. The generation of a conjugated worm is based on application of a tilted head-cutter (grinding tool) as well. The bearing contact of the gear drive is localized and is oriented longitudinally. A predesigned parabolic function of transmission errors for reduction of noise and vibration is provided. The stress analysis of the gear drive is performed using a three-dimensional finite element analysis. The contacting model is automatically generated. The developed theory is illustrated with numerical examples.

  9. Spirit's First Grinding of a Rock on Mars

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The round, shallow depression in this image resulted from history's first grinding of a rock on Mars. The rock abrasion tool on NASA's Spirit rover ground off the surface of a patch 45.5 millimeters (1.8 inches) in diameter on a rock called Adirondack. The hole is 2.65 millimeters (0.1 inch) deep, exposing fresh interior material of the rock for close inspection with the rover's microscopic imager and two spectrometers on the robotic arm. This image was taken by Spirit's panoramic camera, providing a quick visual check of the success of the grinding. The rock abrasion tools on both Mars Exploration Rovers were supplied by Honeybee Robotics, New York, N.Y.

  10. Teeth Grinding: Is Emotional Stability related to Bruxism?

    PubMed

    Sutin, Angelina R; Terracciano, Antonio; Ferrucci, Luigi; Costa, Paul T

    2010-06-01

    This study examines the association between personality traits and bruxism, the repetitive grinding or clenching of teeth. Community-dwelling participants (N = 470) had a comprehensive oral examination by a dentist and completed a dental history and personality questionnaires. Consistent with the literature on state anxiety and depression as antecedents of bruxism, Neuroticism-related traits were associated with self-reported teeth grinding. These traits were also associated with other oral complaints often associated with anxiety (jaw clicks, difficulty chewing food, and dry mouth), but not with more general oral health complaints (unhealthy gums, bleeding gums, and canker sores) or with dentist-assessed occlusal wear or tongue indentations. This study provides evidence for the association between Neuroticism and bruxism and other stress-related oral health symptoms. PMID:20835403