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1

Mechanical assessment of grit blasting surface treatments of dental implants.  

PubMed

This paper investigates the influence of surface preparation treatments of dental implants on their potential (mechanical) fatigue failure, with emphasis on grit-blasting. The investigation includes limited fatigue testing of implants, showing the relationship between fatigue life and surface damage condition. Those observations are corroborated by a detailed failure analysis of retrieved fracture dental implants. In both cases, the negative effect of embedded alumina particles related to the grit-blasting process is identified. The study also comprises a numerical simulation part of the grit blasting process that reveals, for a given implant material and particle size, the existence of a velocity threshold, below which the rough surface is obtained without damage, and beyond which the creation of significant surface damage will severely reduce the fatigue life, thus increasing fracture probability. The main outcome of this work is that the overall performance of dental implants comprises, in addition to the biological considerations, mechanical reliability aspects. Fatigue fracture is a central issue, and this study shows that uncontrolled surface roughening grit-blasting treatments can induce significant surface damage which accelerate fatigue fracture under certain conditions, even if those treatments are beneficial to the osseointegration process. PMID:25173238

Shemtov-Yona, K; Rittel, D; Dorogoy, A

2014-11-01

2

Effect of abrasive grit size on wear of manganese-zinc ferrite under three-body abrasion  

NASA Technical Reports Server (NTRS)

Wear experiments were conducted using replication electron microscopy and reflection electron diffraction to study abrasion and deformed layers produced in single-crystal Mn-Zn ferrites under three-body abrasion. The abrasion mechanism of Mn-Zn ferrite changes drastically with the size of abrasive grits. With 15-micron (1000-mesh) SiC grits, abrasion of Mn-Zn ferrite is due principally to brittle fracture; while with 4- and 2-micron (4000- and 6000-mesh) SiC grits, abrasion is due to plastic deformation and fracture. Both microcracking and plastic flow produce polycrystalline states on the wear surfaces of single-crystal Mn-Zn ferrites. Coefficient of wear, total thickness of the deformed layers, and surface roughness of the wear surfaces increase markedly with an increase in abrasive grit size. The total thicknesses of the deformed layers are 3 microns for the ferrite abraded by 15-micron SiC, 0.9 microns for the ferrite abraded by 4-micron SiC, and 0.8 microns for the ferrite abraded by 1-micron SiC.

Miyoshi, Kazuhisa

1987-01-01

3

Grit  

NSDL National Science Digital Library

This page from Character Lab presents information about the trait of grit and its impact in the classroom. The reader learns what grit is, what it looks like, why it is important, and how to develop it in learners. Included is a 5-minute video of Dr. Angela Duckworth discussing the importance of grit in students as well as links to further resources about the topic.

2012-01-01

4

Acid Etching and Plasma Sterilization Fail to Improve Osseointegration of Grit Blasted Titanium Implants  

PubMed Central

Interaction between implant surface and surrounding bone influences implant fixation. We attempted to improve the bone-implant interaction by 1) adding surface micro scale topography by acid etching, and 2) removing surface-adherent pro-inflammatory agents by plasma cleaning. Implant fixation was evaluated by implant osseointegration and biomechanical fixation. The study consisted of two paired animal sub-studies where 10 skeletally mature Labrador dogs were used. Grit blasted titanium alloy implants were inserted press fit in each proximal tibia. In the first study grit blasted implants were compared with acid etched grit blasted implants. In the second study grit blasted implants were compared with acid etched grit blasted implants that were further treated with plasma sterilization. Implant performance was evaluated by histomorphometrical investigation (tissue-to-implant contact, peri-implant tissue density) and mechanical push-out testing after four weeks observation time. Neither acid etching nor plasma sterilization of the grit blasted implants enhanced osseointegration or mechanical fixation in this press-fit canine implant model in a statistically significant manner. PMID:22962567

Saks?, Mikkel; Jakobsen, Stig S; Saks?, Henrik; Baas, J?rgen; Jakobsen, Thomas; S?balle, Kjeld

2012-01-01

5

Abrasive Blasting Agents: Designing Studies to Evaluate Relative Risk  

Microsoft Academic Search

Workers exposed to respirable crystalline silica used in abrasive blasting are at increased risk of developing a debilitating and often fatal fibrotic lung disease called silicosis. The National Institute for Occupational Safety and Health (NIOSH) recommends that silica sand be prohibited as abrasive blasting material and that less hazardous materials be used in blasting operations. However, data are needed on

Ann Hubbs; Mark Greskevitch; Eileen Kuempel; Fernando Suarez; Mark Toraason

2005-01-01

6

Characterization and dispersion of pollutant releases from the abrasive blasting of lead paint from steel bridges  

SciTech Connect

The characterization of airborne and spent material for abrasive blasting of steel paint was performed as part of the Environmental Impact Statement for Lead Paint Removal Operations on New York City Department of Transportation Bridges1. Laboratory tests were performed on painted steel components of the Williamsburg Bridge, to determine the sizes of particles typically released into the air as aerosol and onto the ground as bulk material, as a result of accidental releases from abrasive blasting operations. Two of the most commonly used abrasives for paint removal on steel structures, recyclable steel grit and expendable abrasives were subjected to the laboratory tests. The results of the tests were used to determine the percentage of existing paint and abrasive which becomes airborne and the resultant particle size distributions, which were employed in the air quality concentration and deposition modeling for the EIS. Particle size distributions of the airborne material indicated that the profiles of airborne lead and particulate matter have a mean particle size between 15 and 21 microns. Spent abrasives and paint chips that settle on the floor are larger in size with a mean diameter greater than 259 microns, although up to 6% of this material has a mean diameter less than 50 microns. The percentage of paint and expendable abrasives that become airborne as a result of abrasive blasting were estimated to be as high as 9.0 and 12.4%, respectively. Potential release rates were derived for total accumulation (duration of the project), annual, quarterly, 24-hour, and 1-hour time averaging periods for abrasives, lead, and other metals. Pollutant releases were simulated as individual sources at multiple release heights with the Environment Protection Agency's ISC3ST model for six representative bridges near potential places of public exposure.

Lee, M.; Rana, B.

1999-07-01

7

The effect of grit size and asperity blunting on abrasive wear  

Microsoft Academic Search

A model of abrasive wear, which has been used successfully to predict the forces and metal removal rates in abrasive machining is extended to allow the prediction of abrasive deterioration. Attritious wear of the abrasive and transfer of debris are both important factors in reducing abrasive wear over time, but small abrasives are more prone to becoming clogged by debris.

A. A Torrance

2002-01-01

8

Analysis of Abrasive Blasting of DOP-26 Iridium Alloy  

SciTech Connect

The effects of abrasive blasting on the surface geometry and microstructure of DOP-26 iridium alloy (Ir-0.3% W-0.006% Th 0.005% Al) have been investigated. Abrasive blasting has been used to control emissivity of components operating at elevated temperature. The effects of abrasive blasting conditions on surface morphology were investigated both experimentally and by numerical modeling. The simplified model, based on finite element analysis of a single angular particle impacting on Ir alloy disk, calculates the surface deformation and residual strain distribution. The experimental results and modeling results both indicate that the surface geometry is not sensitive to the abrasive blast process conditions of nozzle pressure and standoff distance considered in this study. On the other hand, the modeling results suggest that the angularity of the abrasive particle has an important role in determining surface geometry, which in turn, affects the emissivity. Abrasive blasting causes localized surface strains and localized recrystallization, but it does not affect grain size following extended exposure at elevated temperature. The dependence of emissivity of the DOP-26 alloy on mean surface slope follows a similar trend to that reported for pure iridium.

Ohriner, Evan Keith [ORNL; Zhang, Wei [ORNL; Ulrich, George B [ORNL

2012-01-01

9

Atmospheric particulate emissions from dry abrasive blasting using coal slag  

SciTech Connect

Coal slag is one of the widely used abrasives in dry abrasive blasting. Atmospheric emissions from this process include particulate matter (PM) and heavy metals, such as chromium, lead, manganese, nickel. Quantities and characteristics of PM emissions depend on abrasive characteristics and process parameters. Emission factors are key inputs to estimate emissions. Experiments were conducted to study the effect of blast pressure, abrasive feed rate, and initial surface contamination on total PM (TPM) emission factors for coal slag. Rusted and painted mild steel surfaces were used as base plates. Blasting was carried out in an enclosed chamber, and PM was collected from an exhaust duct using U.S. Environment Protection Agency source sampling methods for stationary sources. Results showed that there is significant effect of blast pressure, feed rate, and surface contamination on TPM emissions. Mathematical equations were developed to estimate emission factors in terms of mass of emissions per unit mass of abrasive used, as well as mass of emissions per unit of surface area cleaned. These equations will help industries in estimating PM emissions based on blast pressure and abrasive feed rate. In addition, emissions can be reduced by choosing optimum operating conditions. 40 refs., 5 figs., 2 tabs.

Bhaskar Kura; Kalpalatha Kambham; Sivaramakrishnan Sangameswaran; Sandhya Potana [University of New Orleans, New Orleans, LA (United States). Department of Civil and Environmental Engineering

2006-08-15

10

Atmospheric particulate emissions from dry abrasive blasting using coal slag.  

PubMed

Coal slag is one of the widely used abrasives in dry abrasive blasting. Atmospheric emissions from this process include particulate matter (PM) and heavy metals, such as chromium, lead, manganese, nickel. Quantities and characteristics of PM emissions depend on abrasive characteristics and process parameters. Emission factors are key inputs to estimate emissions. Experiments were conducted to study the effect of blast pressure, abrasive feed rate, and initial surface contamination on total PM (TPM) emission factors for coal slag. Rusted and painted mild steel surfaces were used as base plates. Blasting was carried out in an enclosed chamber, and PM was collected from an exhaust duct using U.S. Environment Protection Agency source sampling methods for stationary sources. Results showed that there is significant effect of blast pressure, feed rate, and surface contamination on TPM emissions. Mathematical equations were developed to estimate emission factors in terms of mass of emissions per unit mass of abrasive used, as well as mass of emissions per unit of surface area cleaned. These equations will help industries in estimating PM emissions based on blast pressure and abrasive feed rate. In addition, emissions can be reduced by choosing optimum operating conditions. PMID:16933653

Kura, Bhaskar; Kambham, Kalpalatha; Sangameswaran, Sivaramakrishnan; Potana, Sandhya

2006-08-01

11

The removal of Al2O3 particles from grit-blasted titanium implant surfaces: effects on biocompatibility, osseointegration and interface strength in vivo.  

PubMed

For the improvement of surface roughness and mechanical interlocking with bone, titanium prostheses are grit-blasted with Al(2)O(3) particles during manufacturing. Dislocated Al(2)O(3) particles are a leading cause of third-body abrasive wear in the articulation of endoprosthetic implants, resulting in inflammation, pain and ultimately aseptic loosening and implant failure. In the present study, a new treatment for the removal of residual Al(2)O(3) particles from grit-blasted, cementless titanium endoprosthetic devices was investigated in a rabbit model. The cleansing process reduces residual Al(2)O(3) particles on titanium surfaces by up to 96%. The biocompatibility of the implants secondary to treatment was examined histologically, the bone-implant contact area was quantified histomorphometrically, and interface strength was evaluated with a biomechanical push-out test. Conventional grit-blasted implants served as control. In histological and SEM analysis, the Al(2)O(3)-free implant surfaces demonstrated uncompromised biocompatibility. Histomorphometrically, Al(2)O(3)-free implants exhibited a significantly increased bone-implant contact area (p=0.016) over conventional implants between both evaluation points. In push-out testing, treated Al(2)O(3)-free implants yielded less shear resistance than conventional implants at both evaluation points (p=0.018). In conclusion, the new surface treatment effectively removes Al(2)O(3) from implant surfaces. The treated implants demonstrated uncompromised biocompatibility and bone apposition in vivo. Clinically, Al(2)O(3)-free titanium prostheses could lead to less mechanical wear of the articulating surfaces and ultimately result in less aseptic loosening and longer implant life. PMID:20080212

Rüger, Matthias; Gensior, Tobias J; Herren, Christian; von Walter, Matthias; Ocklenburg, Christina; Marx, Rudolf; Erli, Hans-Josef

2010-07-01

12

Bendable Extension For Abrasive-Jet Cleaning  

NASA Technical Reports Server (NTRS)

Hard-to-reach places cleaned more easily. Extension for abrasive-jet apparatus bent to provide controlled abrasive cleaning of walls in deep cavities or other hard-to-reach places. Designed for controlled removal of penetrant inspection dyes from inside castings, extension tube also used for such general grit-blasting work as removal of scratches.

Mayer, Walter

1989-01-01

13

Investigation of Abrasiveness Property of Blast Furnace Slag on Ceramic Coatings via the Abrasive Slurry Wear Method  

Microsoft Academic Search

In this study, the abrasiveness property of blast furnace slags emerging as a waste material in the production of crude iron was investigated. The abrasive slurry wear (ASW) method was used for experiments. For abrasiveness tests, oxides (Al2O3, Al2O3–13% TiO2, Al2O3–40%TiO2, Cr2O3), including ceramics, which is coated on the AISI 1040 medium carbon steel surface via the plasma spray coating

Yilmaz Kucuk

2012-01-01

14

Surface assessment and modification of concrete using abrasive blasting  

NASA Astrophysics Data System (ADS)

Composite systems are applied to concrete substrates to strengthen and extend the service life. Successful restoration or rehabilitation requires surface preparation prior to the application of the overlay. Surface coatings, waterproofing systems, and other external surface applications also require surface preparation prior to application. Abrasive blast media is often used to clean and uniformly roughen the substrate. The appropriate surface roughness is necessary to facilitate a strong bond between the existing substrate and overlay. Thus, surface modification using abrasive blast media (sand and dry ice), their respective environmental effects, surface roughness characterization prior to and after blasting, and the adhesion between the substrate and overlay are the focus of this dissertation. This dissertation is comprised of an introduction, a literature review, and four chapters, the first of which addresses the environmental effects due to abrasive blasting using sand, water, and dry ice. The assessment considered four response variables: carbon dioxide (CO2) emissions, fuel and energy consumption, and project duration. The results indicated that for sand blasting and water jetting, the primary factor contributing to environmental detriment was CO22 emissions from vehicular traffic near the construction site. The second chapter is an analysis of the International Concrete Repair Institute's (ICRI) concrete surface profiles (CSPs) using 3-D optical profilometry. The primary objective was to evaluate the suitability of approximating the 3-D surface (areal) parameters with those extracted from 2-D (linear) profiles. Four profile directions were considered: two diagonals, and lines parallel and transverse to the longitudinal direction of the mold. For any CSP mold, the estimation of the 3-D surface roughness using a 2-D linear profile resulted in underestimation and overestimation errors exceeding 50%, demonstrating the inadequacy of 2-D linear profiles to approximate the 3-D concrete surface profiles. The errors were reduced when a weighted average of the four linear profiles approximated the corresponding 3-D parameter. The following chapter considers the parametric and sensitivity of concrete surface topography measurements. The weighted average of the four 2-D profiles consistently resulted in underestimation of the corresponding 3-D parameters: the dispersion of surface elevations (Sq) and the roughness (Sa). Results indicated the 3-D parameter, Sq, had the least sensitivity to data point reduction. The final chapter investigated surface modification using dry ice and sand blasting. The overall objective was to evaluate the change in the 3-D surface roughness (Sa) following blasting as functions of mix design and as induced by freeze-thaw cycling, and to compare the results obtained using dry ice with those obtained using sand as the blasting media. In general, sand blasting produced larger changes in Sa compared to dry ice blasting for the concrete mix designs considered. The primary mechanism responsible for altering the surface topography of the concrete was the scaling of the superficial cement paste layer on the exposed surface, which was due to freeze-thaw cycling. The largest relative change in roughness following blasting occurred in the control samples, which had not undergone freeze-thaw cycling.

Millman, Lauren R.

15

Grit-blasted and hydroxyapatite-coated total hip arthroplasty: an 11- to 14-year follow-up study  

Microsoft Academic Search

We report long-term results of the first clinical trial of hydroxyapatite-coated total hip arthroplasty conducted in Japan. The hemispherical cup and the straight-tapered stem were made of titanium alloy with a grit-blasted, hydroxyapatite-coated surface. The surface roughness before and after hydroxyapatite coating was 1.4?µm and 3.4?µm, respectively. Thirty-three patients (35 hips) were followed prospectively; of these, 1 patient was lost

Shumpei Miyakawa; Haruo Kawamura; Hajime Mishima; Jun Yasumoto

2004-01-01

16

Separation and quantitation of hazardous wastes from abrasive blast media.  

PubMed

A sample of glass bead abrasive blasting material (ABM) waste, received from Robins Air Force Base (Georgia), was examined to determine whether the waste could be rendered nonhazardous by separating paint contaminants from the ABM. The sample was analyzed with size distribution and toxicity characteristics leaching procedure. A Microtrac analyzer was used to measure the size of fine particles (-325 Tyler mesh), and scanning electron microscopy analysis was performed to identify the nature of the contaminants in the ABM waste. Tests using froth flotation, magnetic separation, desliming, and acid washing were conducted to develop a process for removing the contaminants. A pilot plant test using the developed process rendered 82.1% or the ABM waste material nonhazardous. PMID:11417633

Hwang, J Y; Jeong, M L

2001-01-01

17

Cracks in glass electrical connector headers removed by dry blasting with fine abrasive  

NASA Technical Reports Server (NTRS)

Cracking that causes pressure leakage in glass connector headers can be alleviated by manipulating the pin bridgewire connectors. This initiates the surface and meniscus cracks. Dry blasting the header surface with a fine abrasive then removes the cracks.

Eckert, R. W.

1967-01-01

18

Exposure to crystalline silica in abrasive blasting operations where silica and non-silica abrasives are used.  

PubMed

Exposure to respirable crystalline silica is a hazard common to many industries in Alberta but particularly so in abrasive blasting. Alberta occupational health and safety legislation requires the consideration of silica substitutes when conducting abrasive blasting, where reasonably practicable. In this study, exposure to crystalline silica during abrasive blasting was evaluated when both silica and non-silica products were used. The crystalline silica content of non-silica abrasives was also measured. The facilities evaluated were preparing metal products for the application of coatings, so the substrate should not have had a significant contribution to worker exposure to crystalline silica. The occupational sampling results indicate that two-thirds of the workers assessed were potentially over-exposed to respirable crystalline silica. About one-third of the measurements over the exposure limit were at the work sites using silica substitutes at the time of the assessment. The use of the silica substitute, by itself, did not appear to have a large effect on the mean airborne exposure levels. There are a number of factors that may contribute to over-exposures, including the isolation of the blasting area, housekeeping, and inappropriate use of respiratory protective equipment. However, the non-silica abrasives themselves also contain silica. Bulk analysis results for non-silica abrasives commercially available in Alberta indicate that many contain crystalline silica above the legislated disclosure limit of 0.1% weight of silica per weight of product (w/w) and this information may not be accurately disclosed on the material safety data sheet for the product. The employer may still have to evaluate the potential for exposure to crystalline silica at their work site, even when silica substitutes are used. Limited tests on recycled non-silica abrasive indicated that the silica content had increased. Further study is required to evaluate the impact of product recycling on crystalline silica content for non-silica abrasives. Measurement of blaster exposure was challenging in this study as the blasters evaluated conducted this task intermittently throughout the work shift, frequently removing their blasting helmets. In spite of the challenges in accurately measuring blaster exposure, the measurements were still, for the most part, over the 8-h OEL. Further work is required to develop more effective sampling strategies to evaluate blaster exposure over the full work shift when task-based monitoring is not practical. PMID:24353009

Radnoff, Diane L; Kutz, Michelle K

2014-01-01

19

Study on cylindrical magnetic abrasive finishing using unbonded magnetic abrasives  

Microsoft Academic Search

The process principle and the finishing characteristics of unbonded magnetic abrasive within cylindrical magnetic abrasive finishing are described in this study. The unbonded magnetic abrasive is a mechanical mixture of SiC abrasive and ferromagnetic particles with a SAE30 lubricant. Iron grit and steel grit, for which three various particle sizes were prepared for both, were used as ferromagnetic particles, each

Geeng-Wei Chang; Biing-Hwa Yan; Rong-Tzong Hsu

2002-01-01

20

Abrasive flow finishing of stereolithography prototypes  

Microsoft Academic Search

This research investigated the use of two relatively new technologies, abrasive flow machining (AFM) and stereolithography (SL), to minimize the time to develop a finished prototype. Statistical analysis was used to determine effects of media grit size, media pressure, build style, build orientation and resin type on flatness, material removal rate and surface roughness. Results indicated that media pressure, grit

Robert E. Williams; Vicki L. Melton

1998-01-01

21

Monitoring and Testing the Parts Cleaning Stations, Abrasive Blasting Cabinets, and Paint Booths  

NASA Technical Reports Server (NTRS)

I have the opportunity to work in the Environmental Management Office (EMO) this summer. One of the EMO's tasks is to make sure the Environmental Management System is implemented to the entire Glenn Research Center (GRC). The Environmental Management System (EMS) is a policy or plan that is oriented toward minimizing an organization's impact to the environment. Our EMS includes the reduction of solid waste regeneration and the reduction of hazardous material use, waste, and pollution. With the Waste Management Team's (WMT) help, the EMS can be implemented throughout the NASA Glenn Research Center. The WMT is responsible for the disposal and managing of waste throughout the GRC. They are also responsible for the management of all chemical waste in the facility. My responsibility is to support the waste management team by performing an inventory on parts cleaning stations, abrasive cabinets, and paint booths through out the entire facility. These booths/stations are used throughout the center and they need to be monitored and tested for hazardous waste and material. My job is to visit each of these booths/stations, take samples of the waste, and analyze the samples.

Jordan, Tracee M.

2004-01-01

22

Co-blasting of titanium surfaces with an abrasive and hydroxyapatite to produce bioactive coatings: substrate and coating characterisation.  

PubMed

The aim of this work is to assess the influence of two blast media on the deposition of hydroxyapatite onto a titanium substrate using a novel ambient temperature coating technique named CoBlast. CoBlast was developed to address the problems with high temperature coating techniques. The blasting media used in this study were Al2O3 and a sintered apatite powder. The prepared and coated surfaces were compared to plasma sprayed hydroxyapatite on the same substrates using the same hydroxyapatite feedstock powder. X-ray diffraction analysis revealed the coating crystallinity was the same as the original hydroxyapatite feedstock powder for the CoBlast samples while evidence of amorphous hydroxyapatite phases and ?-TCP was observed in the plasma sprayed samples. The blast media type significantly influences the adhesive strength of the coating, surface roughness of both the substrate and coating and the microstructure of the substrate. The coating adhesion increased for the CoBlasted samples from 50?MPa to 60?MPa for sintered apatite powder and alumina, respectively, while plasma spray samples were significantly lower (5?MPa) when tested using a modified pull-test. In conclusion, the choice of blast medium is shown to be a key parameter in the CoBlast process. This study indicates that sintered apatite powder is the most suitable candidate for use as a blast medium in the coating of medical devices. PMID:23520359

Dunne, Conor F; Twomey, Barry; O'Neill, Liam; Stanton, Kenneth T

2014-01-01

23

Abrasive slurry composition for machining boron carbide  

DOEpatents

An abrasive slurry particularly suited for use in drilling or machining boron carbide consists essentially of a suspension of boron carbide and/or silicon carbide grit in a carrier solution consisting essentially of a dilute solution of alkylaryl polyether alcohol in octyl alcohol. The alkylaryl polyether alcohol functions as a wetting agent which improves the capacity of the octyl alcohol for carrying the grit in suspension, yet without substantially increasing the viscosity of the carrier solution.

Duran, E.L.

1984-11-29

24

Abrasive slurry composition for machining boron carbide  

DOEpatents

An abrasive slurry particularly suited for use in drilling or machining boron carbide consists essentially of a suspension of boron carbide and/or silicon carbide grit in a carrier solution consisting essentially of a dilute solution of alkylaryl polyether alcohol in octyl alcohol. The alkylaryl polyether alcohol functions as a wetting agent which improves the capacity of the octyl alcohol for carrying the grit in suspension, yet without substantially increasing the viscosity of the carrier solution.

Duran, Edward L. (Santa Fe, NM)

1985-01-01

25

Friction and wear with a single-crystal abrasive grit of silicon carbide in contact with iron base binary alloys in oil: Effects of alloying element and its content  

NASA Technical Reports Server (NTRS)

Sliding friction experiments were conducted with various iron-base binary alloys (alloying elements were Ti, Cr, Mn, Ni, Rh, and W) in contact with a rider of 0.025-millimeter-radius, single-crystal silicon carbide in mineral oil. Results indicate that atomic size and content of alloying element play a dominant role in controlling the abrasive-wear and -friction properties of iron-base binary alloys. The coefficient of friction and groove height (wear volume) general alloy decrease, and the contact pressure increases in solute content. There appears to be very good correlation of the solute to iron atomic radius ratio with the decreasing rate of coefficient of friction, the decreasing rate of groove height (wear volume), and the increasing rate of contact pressure with increasing solute content C. Those rates increase as the solute to iron atomic radius ratio increases from unity.

Miyoshi, K.; Buckley, D. H.

1979-01-01

26

A slip-line field model of abrasive wear  

Microsoft Academic Search

Slip-line fields are used to describe the three main interactions between abrasive grit and metal: ploughing, wedge formation and cutting. Combining these with ratchetting, or low-cycle fatigue models of mild wear, allows wear coefficients to be predicted from the mechanical properties of the metal and the profile of the abrasive. The predictions are verified by experiment, and are in accord

A. A. Torrance; T. R. Buckley

1996-01-01

27

Abrasion of flat rotating shapes.  

PubMed

We report on the erosion of flat linoleum "pebbles" under steady rotation in a slurry of abrasive grit. To quantify shape as a function of time, we develop a general method in which the pebble is photographed from multiple angles with respect to the grid of pixels with a digital camera. This reduces digitization noise and allows the local curvature of the contour to be computed with a controllable degree of uncertainty. Several shape descriptors are then employed to follow the evolution of different initial shapes toward a circle, where abrasion halts. The results are in good quantitative agreement with a simple model, where we propose that points along the contour move radially inward in proportion to the product of the radius and the derivative of radius with respect to angle. PMID:21517490

Roth, A E; Marques, C M; Durian, D J

2011-03-01

28

A model for the abrasive wear behaviour of aluminium based composites  

Microsoft Academic Search

The abrasive wear behaviour of SiCp-reinforced composites was investigated using pin-on-disc type of machine where the sample slid against SiC abrasive of different grit sizes. The abrasive wear of the composite and its alloy matrix was developed in terms of the applied load, sliding distance and particle size using factorial design. It was demonstrated through established equations that the wear

Y. Sahin; K. Özdin

2008-01-01

29

Air Abrasion  

MedlinePLUS

... cracks and discolored teeth, to prepare teeth for bonding procedures, such as sealants, and for various other procedures. Air abrasion works ... remove stains and spots; repair old fillings and sealants; and repair broken crowns and bridges. Your general ...

30

ORIGINAL PAPER Use of grit supplements by waterbirds: an experimental  

E-print Network

ORIGINAL PAPER Use of grit supplements by waterbirds: an experimental assessment of strategies. Lead ammunition for hunting is being progressively banned in more countries, while grit supplementation supplemented with grit was higher than in those without grit, although the highest numbers of feeding birds

Green, Andy J.

31

Grit Denker, Ph.D. SRI International  

E-print Network

Grit Denker, Ph.D. SRI International Senior Computer Scientist Computer Science Laboratory and a machine -- "the last meter bandwidth." bRIGHT will increase efficiency to Lockheed Martin in DARPA's Behavioral Learning for Adaptive Electronic Warfare (BLADE

Denker, Grit

32

Glycaemic Response to Quality Protein Maize Grits  

PubMed Central

Background. Carbohydrates have varied rates of digestion and absorption that induces different hormonal and metabolic responses in the body. Given the abundance of carbohydrate sources in the Philippines, the determination of the glycaemic index (GI) of local foods may prove beneficial in promoting health and decreasing the risk of diabetes in the country. Methods. The GI of Quality Protein Maize (QPM) grits, milled rice, and the mixture of these two food items were determined in ten female subjects. Using a randomized crossover design, the control bread and three test foods were given on separate occasions after an overnight fast. Blood samples were collected through finger prick at time intervals of 0, 15, 30, 45, 60, 90, and 120 min and analyzed for glucose concentrations. Results. The computed incremental area under the glucose response curve (IAUC) varies significantly across test foods (P < .0379) with the pure QPM grits yielding the lowest IAUC relative to the control by 46.38. Resulting GI values of the test foods (bootstrapped) were 80.36 (SEM 14.24), 119.78 (SEM 18.81), and 93.17 (SEM 27.27) for pure QPM grits, milled rice, and rice-QPM grits mixture, respectively. Conclusion. Pure QPM corn grits has a lower glycaemic response compared to milled rice and the rice-corn grits mixture, which may be related in part to differences in their dietary fibre composition and physicochemical characteristics. Pure QPM corn grits may be a more health beneficial food for diabetic and hyperlipidemic individuals. PMID:20862364

Panlasigui, Leonora N.; Bayaga, Cecile L. T.; Barrios, Erniel B.; Cochon, Kim L.

2010-01-01

33

Material response to particle impact during abrasive jet machining of alumina ceramics  

Microsoft Academic Search

Abrasive jet machining (AJM), a specialized form of shot blasting, attracts much attention as a hopeful micro-machining method for hard, brittle materials such as structural ceramics. The present paper attempts to identify the material response of alumina ceramics to the abrasive particle impact in the AJM process. Three kinds of commercial abrasive particles were utilized to dimple the sintered alumina

Manabu Wakuda; Yukihiko Yamauchi; Shuzo Kanzaki

2003-01-01

34

7 CFR 3201.78 - Blast media.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Blast media. 3201.78 Section 3201.78 Agriculture... Designated Items § 3201.78 Blast media. (a) Definition. Abrasive particles...preference for qualifying biobased blast media. By that date, Federal agencies...

2013-01-01

35

7 CFR 3201.78 - Blast media.  

...2014-01-01 2014-01-01 false Blast media. 3201.78 Section 3201.78 Agriculture... Designated Items § 3201.78 Blast media. (a) Definition. Abrasive particles...preference for qualifying biobased blast media. By that date, Federal agencies...

2014-01-01

36

Abrasion resistance of stainless-steel composites reinforced with hard TiB 2 particles  

Microsoft Academic Search

AISI 304 stainless steel and composites reinforced with various volume fractions of TiB2 particles were fabricated by hot-isostatic pressing. Pin-on-disc measurements were used to study the two-body abrasive wear behaviour of stainless steel and the composites. In the tests, the pin specimen was sliding against the counterpart disc bonded with an abrasive SiC paper of 240 grit size. The results

S. C. Tjong; K. C. Lau

2000-01-01

37

The mechanical value of grit for bobwhite quail  

USGS Publications Warehouse

An investigation on the need of grit as a grinding agent in the digestive processes of bobwhite quail was conducted with 1,372 pen-raised birds at the Patuxent Research Refuge, Bowie, Maryland. Some of the stock was reared, maintained through winter, and bred without access to any grit, although the diet after the tenth week consisted of whole seeds......As to survival, weight, and efficiency of feed consumption, the birds without grit during their period of growth equalled those with access to grit. Such birds, when continued on a gritless regimen during the winter, survived and maintained their weight as successfully as birds on grit. There were no gizzard lesions, and the digestion of whole seeds was satisfactory. Subsequent health and reproduction were unaffected by the absence of grit......The quail reared with access to grit retained an appreciable supply of grit in their gizzards for five months after being deprived of it.

Nestler, R.B.

1946-01-01

38

BRASENOSE COLLEGE ASSESSMENT AND PROCEDURE FOR SALTING/GRITTING ROADS,  

E-print Network

BRASENOSE COLLEGE ASSESSMENT AND PROCEDURE FOR SALTING/GRITTING ROADS, AND CAR PARKS (INCLUDING, as a precaution, distribute either salt or grit to the priority areas as indicated on the attached plan (appendix Accumulations Where a prior forecast has precipitated a precautionary gritting/salting, but over night

Oxford, University of

39

Modelling of two-body abrasive wear under multiple contact conditions  

Microsoft Academic Search

A general model for wear rate and specific wear energy of materials in two-body abrasive wear under multiple contact conditions is presented. Wear mode transitions and material removal fraction have been considered. This model is further evaluated under various conditions by assuming conical particles with round tips. To validate the model, the effect of grit size and repeated sliding on

Jiaren Jiang; Fanghui Sheng; Fengshen Ren

1998-01-01

40

Background to plastic media blasting  

NASA Astrophysics Data System (ADS)

Chemical strippers based on active phenolic components in a chlorinated solvent have been the traditional method for removing of paints and coatings from aircraft. With the recent recognition of the environmental and health concerns of chlorinated solvents and the problem disposing of phenols there have been some major developments in paint removal technology. One of the first techniques developed to replace chemical strippers and now one of the most widely used techniques for paint removal from aircraft was plastic media blasting (PMB). The PMB technique is similar to traditional grit blasting (slag, sand alumina or carborundum) techniques used on steel and other metals (based on grits) but using polymer based media that are softer and less aggressive. Plastic media are ranked by hardness and density as well as chemical composition.

Foster, Terry

1995-04-01

41

Hot-filament chemical vapor deposition of amorphous carbon film on diamond grits and induction brazing of the diamond grits  

NASA Astrophysics Data System (ADS)

The production of a high-quality brazed diamond tool has gradually drawn the attention of the tool industry. Hot-filament chemical vapor deposition (CVD) of amorphous carbon film on diamond grits was conducted. The deposited diamond grits were used to make brazed diamond tools by induction heating. Amorphous carbon film (1-2 ?m thick) was deposited onto the diamond surface. The diamond grits protruding from the filler alloy maintain their sharpness after induction brazing of the deposited diamond grits. Discontinuous irregular carbides are distributed evenly on the brazed diamond surface in the filler alloy. This considerably enhances the bonding strength between the filler alloy and diamond grits. Grinding tests of the brazed diamond wheels show a low percentage of pullouts from the matrix and whole grain fracture for the deposited diamond grits brazed by induction heating.

Ma, Bojiang; Yu, Qingxian

2012-03-01

42

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

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

43

The effect of particle feed rate on the plastic media blast jet  

Microsoft Academic Search

Paint removal from military aircraft is often done by plastic media blasting (PMB): the use of plastic grit in a conventional blast jet. However, there is some concern that PMB will cause damage. To help in evaluating this possibility, a time of flight'' meter is used to measure particle velocity in the jet, as a function of air pressure, distance

M. J. McIntosh

1992-01-01

44

ORIGINAL PAPER Use of grit supplements by waterbirds: an experimental  

E-print Network

. Wildlife conservation . Wildlife management Introduction Gastroliths, more commonly known as grit, are used of mortality for some species. Lead ammunition for hunting is being progressively banned in more countries, while grit supplementation has been proposed as a management measure to reduce the ingestion

Paris-Sud XI, Université de

45

Grit: Perseverance and Passion for Long-Term Goals  

Microsoft Academic Search

The importance of intellectual talent to achievement in all professional domains is well established, but less is known about other individual differences that predict success. The authors tested the importance of 1 noncognitive trait: grit. Defined as perseverance and passion for long-term goals, grit accounted for an average of 4% of the variance in success outcomes, including educational attainment among

Angela L. Duckworth; Christopher Peterson; Michael D. Matthews; Dennis R. Kelly

2007-01-01

46

Electrolytic magnetic abrasive finishing  

Microsoft Academic Search

Electrolytic magnetic abrasive finishing (EMAF) is a compound finishing process, involving traditional magnetic abrasive finishing (MAF) and an electrolytic process. The aim of including the electrolytic process into the EMAF system is to produce a passive film (or oxide film), which is much easier to remove than the original metal surface during processing. Moreover, in the presence of both electric

Biing-Hwa Yan; Geeng-Wei Chang; Tsung-Jen Cheng; Rong-Tzong Hsu

2003-01-01

47

Modelling abrasive wear  

Microsoft Academic Search

The abrasive wear rates of materials may be very simply related to their mechanical properties, provided wear takes place under very simple conditions. However, wear rates in many practical situations can be controlled by effects which either relate to mechanical properties in more subtle ways, or which are controlled by quite different parameters. Mechanics models of the abrasive process provide

A. A. Torrance

2005-01-01

48

Continuum model of abrasive layer in an abrasive wear test  

Microsoft Academic Search

In order to find out the relationship between driving torque and thickness of abrasive layer of a three-body abrasive wear system, a continuum model of abrasive layer was proposed. The model is based on the assumption of continuum of abrasive particles and a continuous contact pressure distribution was obtained. A sand crushing test was designed to get compressive behavior of

Qing Shao

2005-01-01

49

Abrasive wear in multiphase microstructures  

Microsoft Academic Search

General theories of abrasive wear are reviewed, and wear is related to abrasive size, shape, hardness and degradation tendency.\\u000a The effects of matrix and second phase flowfracture properties on abrasive wear resistance are discussed. Treatment of matrix\\u000a effects includes the roles of matrix microhardness, subsurface deformation and retained austenite on abrasion resistance.\\u000a Discussion of second phase particle effects includes abrasion

T. H. Kosel; N. F. Fiore

1981-01-01

50

Abrasion of yardangs.  

PubMed

A model for the collision between a sand grain and a body of yardang material is established by using the principles of classical mechanics. A new nondimensional parameter, the "abrasion number" A(n), is derived from the model. The volume removed per impact for different targets is proportional to A(n) approximately. As an indicator of the energy ratio of the impacting material to the target material, A(n) not only reflects the previous "abrasion law" but also introduces two dominant mechanical parameters, Young's modulus and yield stress. We propose A(n) to be a similarity criterion for abrasion experiments. The practicability of the model under natural conditions is examined by an example. It is concluded that the abrasion rates of yardangs in the western Qaidam basin, China, are 0.011-0.398 mm/yr in the period of 1986 to 2010 and remarkable abrasion events generally correspond with strong wind conditions. The model will be helpful for reconstructing the history of aeolian activities from the morphologies of yardangs in the arid regions on Mars. PMID:22060358

Wang, Zhen-Ting; Wang, Hong-Tao; Niu, Qing-He; Dong, Zhi-Bao; Wang, Tao

2011-09-01

51

Wear mechanisms in abrasion and erosion of WC\\/Co and related hardmetals  

Microsoft Academic Search

This paper describes observations of wear mechanisms made through examination of the surfaces of WC hardmetals samples tested in a number of different laboratory abrasion and erosion wear tests.The tests that were used included ASTM G65 and ASTM B611 abrasive tests, scratch testing at a range of different loads and with different indenter geometries, and gas blast erosion.Evaluation of the

M. G. Gee; A. Gant; B. Roebuck

2007-01-01

52

Taking a Closer Look at the "Grit" Narratives  

ERIC Educational Resources Information Center

In this article Ira Socol explores the pros and cons of Paul Tough's "How Children Succeed: Grit, Curiosity, and the Hidden Power of Character." As Tough told Valerie Strauss, "The book is about two things: first, an emerging body of research that shows the importance of so-called non-cognitive skills in children's…

Socol, Ira

2014-01-01

53

Modelling low stress abrasive wear  

Microsoft Academic Search

Low stress abrasive wear tests have been undertaken using a modified ASTM G65 procedure. Wear scar and wear debris morphologies indicate that the principal mechanism of material removal is throuhg the sliding of abrasive particles which form shallow grooves, from which thin platelets of material are removed. It is shown that there is a correlation between the abrasive particle size,

K. Grigoroudis; D. J. Stephenson

1997-01-01

54

Abrasion resistant heat pipe  

DOEpatents

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

Ernst, Donald M. (Leola, PA)

1984-10-23

55

Part III. (1) The Grit Sensitiveness of High Explosives  

Microsoft Academic Search

Risks in handling various high explosives are enhanced if grit is present. Quantitative measurements of the enhanced sensitiveness, made by means of the Rotter impact machine, have included tests on the high explosives: T.N.T., picric acid, tetryl, cyclonite and waxed cyclonite, and penta-erythritol tetranitrate (P.E.T.N.). In addition to the standard Rotter test on the explosives as used in practice, experimental

J. L. Copp; A. R. Ubbelohde

1948-01-01

56

Why birds eat colourful grit: colour preferences revealed by the colour of gizzard stones.  

PubMed

Colour preferences from sexual or social contexts are assumed to have arisen owing to preferences for specific kinds of food, representing a sensory bias, but once colour preferences have evolved in a sexual context, they may also be expressed during foraging. We tested whether preferences for specific body colours (i.e. plumage and soft parts) were related to colour preferences for grit ingested by birds. Birds eat grit to facilitate break down of food by the gizzard, and this function is independent of the colour of grit, but depends on the physical properties of stones. Bird species were significantly consistent in colour of grit, and grit of different colours varied in prevalence among species, even when analyses were restricted to a sample from a single locality. There were positive correlations between presence of lilac and red grit in the gizzard and presence of sexually dichromatic lilac and red colour on the body. There was a positive correlation between red grit colour and red sexually monochromatic body colour. Bird species with many different sexual colours, but not sexually monochromatic colours on their body had many different colours of grit. Males had more lilac and red grit than females, with this effect differing among species, whereas that was not the case for grit of other colours. These findings are consistent with the sensory bias hypothesis that birds express preferences for grit of specific colours and a high diversity of colours related to sexual colouration of the body, even when the colour of such grit is only visible to the individual at the moment of ingestion. PMID:20050966

Møller, A P; Erritzøe, J

2010-03-01

57

Abrasive Wear Resistance of Powder Composites at Abrasive Erosion and Abrasive Impact Wear  

Microsoft Academic Search

Composite materials produced by powder metallurgy provide solution to many engineering applications where materials with high abrasive wear resistance are required. The actual wear behaviour of the material is associated with many external factors (the abrasive particle size, velocity and angularity) and the intrinsic material properties of wear (hardness, toughness, Young modulus, etc.). The hardness and toughness properties of wear

Priit KULU; Renno VEINTHAL; Helmo KÄERDI; Riho TARBE

58

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

NASA Astrophysics Data System (ADS)

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.

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

59

Microscale abrasive wear of polymeric materials  

Microsoft Academic Search

Polymeric materials are now commonly employed as components in mechanical devices, and as such are subject to wear. Abrasive wear of polymer components may occur either by sliding against a rough counterface or by abrasion by hard particles. Whilst previous work has considered the three body abrasion of polymers using large abrasives common in the ASTM G65 test, this work

P. H Shipway; N. K Ngao

2003-01-01

60

Abrasion-resistant antireflective coating for polycarbonate  

NASA Technical Reports Server (NTRS)

Following plasma-polymerization technique, treatment in oxygen glow discharge further enhances abrasion resistance and transmission. Improvement in abrasion resistance was shown by measuring percentage of haze resulting from abrasion. Coating samples were analyzed for abrasion using standard fresh rubber eraser. Other tests included spectra measurements and elemental analysis with spectrometers and spectrophotometers.

Wydeven, T. J.

1978-01-01

61

Tooth Abrasion and Tooth Erosion  

MedlinePLUS

... protects the innermost part of the tooth, the pulp, which contains nerves and blood vessels. Abrasion and erosion also can affect how your teeth look. Diagnosis Your dentist can examine your teeth ...

62

Abrasive wear of cemented carbides  

SciTech Connect

Cemented carbides are used for a wide variety of applications where wear is a problem. Usually the wear of the cemented carbides is a combination of metal-to-metal and abrasion. Wear can occur at room or elevated temperatures. This research summarizes initial research to understand the abrasive wear of various cemented carbides (various grain sizes, carbide types, carbide grain sizes and binder compositions) in terms of absolute material removal rates and material removal mechanisms.

Hawk, Jeffrey A.; Wilson, Rick D.

2003-10-01

63

Size and mass of grit in gizzards of Sandhill Cranes, Tundra Swans, and Mute Swans  

USGS Publications Warehouse

Because it has been suggested that waterbirds may ingest lost or discarded lead fishing weights as grit, we examined grit in the gizzards of Sandhill Cranes (Grus canadensis), Tundra Swans (Cygnus columbianus), and Mute Swans (Cygnus olor), three species where individuals have been poisoned by the ingestion of lead fishing weights. The greatest proportion (by mass) of grit in gizzards of Sandhill Cranes consisted of particles with a minimum dimension of 2.36-4.75 mm. Grit particles in swans were much smaller, with the most prevalent (by mass) being 0.6-1.18 mm. The greatest dimension of the largest grit particle found in cranes and swans was 17.4 mm and 14.0 mm, respectively. The U.S. Environmental Protection Agency has proposed a ban on lead fishing weights of ???25.4 mm in any dimension. Based on the size of grit particles that we found in gizzards of Sandhill Cranes, Mute Swans, and Tundra Swans, we believe it is unlikely that individuals of those species would ingest, as grit, lead fishing weights larger than 25.4 mm in any dimension. Received 10 January 2001, accepted 28 February 2001.

Franson, J.C.; Hansen, S.P.; Duerr, A.E.; DeStefano, S.

2001-01-01

64

Size and mass of grit in gizzards of sandhill cranes, tundra swans, and mute swans.  

USGS Publications Warehouse

Because it has been suggested that waterbirds may ingest lost or discarded lead fishing weights as grit, we examined grit in the gizzards of Sandhill Cranes (Grus canadensis), Tundra Swans (Cygnus columbianus), and Mute Swans (Cygnus olor), three species where individuals have been poisoned by the ingestion of lead fishing weights. The greatest proportion (by mass) of grit in gizzards of Sandhill Cranes consisted of particles with a minimum dimension of 2.36-4.75 mm. Grit particles in swans were much smaller, with the most prevalent (by mass) being 0.6-1.18 mm. The greatest dimension of the largest grit particle found in cranes and swans was 17.4 mm and 14.0 mm, respectively. The U.S. Environmental Protection Agency has proposed a ban on lead fishing weights of ?25.4 mm in any dimension. Based on the size of grit particles that we found in gizzards of Sandhill Cranes, Mute Swans, and Tundra Swans, we believe it is unlikely that individuals of those species would ingest, as grit, lead fishing weights larger than 25.4 mm in any dimension.

Franson, J. Christian; Hansen, Scott P.; Duerr, Adam E.; Destefano, Stephen

2001-01-01

65

Nuclear Blast  

MedlinePLUS

... including blinding light, intense heat (thermal radiation), initial nuclear radiation, blast, fires started by the heat pulse and ... time, and is the main source of residual nuclear radiation. Fallout from a nuclear explosion may be carried ...

66

Mass flow rate measurement in abrasive jets using acoustic emission  

NASA Astrophysics Data System (ADS)

The repeatability of abrasive jet machining operations is presently limited by fluctuations in the mass flow rate due to powder compaction, stratification and humidity effects. It was found that the abrasive mass flow rate for a typical abrasive jet micromachining setup could be determined by using data from the acoustic emission of the abrasive jet impacting a flat plate. Two methods for extracting the mass flow rate from the acoustic emission were developed and compared. In the first method, the number of particle impacts per unit time was determined by a direct count of peaks in the acoustic emission signal. The second method utilizes the power spectrum density of the acoustic emission in a specific frequency range. Both measures were found to correlate strongly with the mass flow rate measured by weighing samples of blasted powder for controlled time periods. It was found that the peak count method permits measurement of the average frequency of the impacts and the mass flow rate, but can only be applied to flow rates in which the impact frequency is approximately one order of magnitude less than the frequency of the target plate ringing. The power spectrum density method of signal processing is applicable to relatively fine powders and to flow rates at which the average impact frequency is of the same order of magnitude as that of the ringing due to the impact. The acoustic emission technique can be used to monitor particle flow variations over a wide range of time periods and provides a straightforward and accurate means of process control.

Ivantsiv, V.; Spelt, J. K.; Papini, M.

2009-09-01

67

LTC 1073 vacuum blasting (concrete) human factors assessment -- Baseline (summary)  

SciTech Connect

The LTC 1073 Vacuum Blasting Machine uses a high capacity, direct pressure blasting system incorporating a continuous feed for the blast media. The blast media cleans the surface within the contained brush area of the blast head. A vacuum system removes dust and debris from the surfaces as it is blasted. After cleaning the surface, the abrasive, together with the rust or coating that was removed from the surface, is vacuumed into the machine through the suction hose. The dust separator contains angled steel collision pads, working with the force of gravity, to allow any reusable abrasive to fall back into the pressure vessel. The filters are manually back flushed to prevent clogging. After back flushing, dust is dumped from the dust chamber into the dust collection bag or drum by operation of the bellows valve. The safety and health evaluation during the testing demonstration focused on dust and noise exposure. Dust exposure was found to be minimal, but noise exposure was potentially significant. Further testing for each of these exposures is recommended because the outdoor environment where the testing demonstration took place may cause the results to be inapplicable to indoor settings. It is feasible that the dust and noise levels will be higher in an enclosed operating environment. Other safety and health issues found were ergonomics, heat stress, tripping hazards, lockout/tagout, and arm-hand vibration.

NONE

1997-07-31

68

Effect of fracture toughness on abrasive wear resistance of steels  

Microsoft Academic Search

Various abrasive wear mechanisms were reviewed and an abrasive wear modeling experiment is assessed. Abrasive wear resistance of non-heat treated and heat treated steels has been determined by using a pin-abrasion machine with five abrasive papers, which grinds on a small pin of test materials. The mass loss of test material during abrasive wear was determined gravimetrically. A correlation between

I. Sevim; I. B. Eryurek

2006-01-01

69

Discrete element method study of abrasion  

Microsoft Academic Search

Abrasion is a surface breakage event where irregular surfaces of particles are removed. In other words, in milling it is the process which produces sphere like particles by comminuting asperities. Extensive experimental work has been performed to study abrasion events and their process parameters. Very few studies have used the discrete element method (DEM) to study the abrasion behavior of

Manoj Khanal; Rob Morrison

2008-01-01

70

Clarification of magnetic abrasive finishing mechanism  

Microsoft Academic Search

In order to clarify the mechanism of magnetic abrasive polishing, a planar type process for a non-magnetic material, stainless steel, was examined. A magnetic abrasive brush was formed between a magnetic pole and a workpiece material, in which the summation of three kinds of energy necessary for magnetization of abrasives, i.e. repulsion between bundles (Faraday effect) and line tension of

T Mori; K Hirota; Y Kawashima

2003-01-01

71

Abrasive wear behaviour of electrodeposited nanocrystalline materials  

Microsoft Academic Search

The effect of grain size refinement on the abrasive wear behaviour of nanocrystalline Ni, Ni-P and Co electrodeposits and the critical materials properties that influence the abrasive wear resistance were studied using the Taber wear test. As the grain size of Ni decreased from 90 mum to 13 nm, the dominant abrasive wear mode changed from ploughing to cutting and

Daehyun Jeong

2003-01-01

72

New concepts in air abrasion.  

PubMed

There is no doubt that air abrasion is going to be part of the millennial shift in dentistry away from traditional treatment modalities. With the change in incidence and morphology of caries as a result of the hardening effect of fluoride on enamel, this ability to remove only decayed areas and permanently seal the less susceptible areas becomes increasingly desirable. PMID:9590961

Porth, R N

1998-03-01

73

Abrasive wear in filled elastomers  

Microsoft Academic Search

The abrasive wear of rubbers is strongly affected by the filler particles dispersed in the elastomer matrix. The fillers are incorporated usually for the purposes of mechanical reinforcement and improving the conductivity of the neat resins. It is found that the wear rates of the filled silicone rubbers increase slowly with filler concentration until a critical volume fraction,vc, is reached,

A. C.-M. Yang; J. E. Ayala; J. Campbell Scott

1991-01-01

74

Decontamination apparatus and method  

DOEpatents

A blast head including a plurality of spray nozzles mounted in a chamber for receiving a workpiece. The several spray nozzles concurrently direct a plurality of streams of a pressurized gas and abrasive grit mixture toward a peripheral portion of the workpiece to remove particulates or debris therefrom. An exhaust outlet is formed in the chamber for discharging the particulates and spent grit.

Oakley, David J. (Richland, WA)

1987-01-01

75

Effect of Enrichment on the Thiamine, Riboflavin and Niacin of Corn Meal and Grits as Prepared for Eating.  

E-print Network

, on account of the milk and eggs in it, were sim- ilar to the higher riboflavin content of the corn breads. Long cooked grits and mush had less thiamine than the short cook- ed. The higher per gram content of each vitamin in fried than in boiled grits..., on account of the milk and eggs in it, were sim- ilar to the higher riboflavin content of the corn breads. Long cooked grits and mush had less thiamine than the short cook- ed. The higher per gram content of each vitamin in fried than in boiled grits...

Whitacre, Jessie; Pace, June K.; Thomas, Kathreen

1952-01-01

76

Effects of different blasting materials on charge generation and decay on titanium surface after sandblasting.  

PubMed

It has been reported that sandblasting titanium with alumina (Al2O3) powder could generate a negative electric charge on titanium surface. This has been proven to promote osteoblast activities and possibly osseointegration. The purpose of this pilot study was to investigate the effects of different blasting materials, in terms of the grit sizes and electro-negativity, on the generation of a negative charge on the titanium surface. The aim was also to make use of these results to deduct the underlying mechanism of charge generation by sandblasting. Together 60 c.p. 2 titanium plates were machine-cut and polished for sandblasting, and divided into 6 groups with 10 plates in each. Every plate in the study groups was sandblasted with one of the following 6 powder materials: 110µm Al2O3 grits, 50µm Al2O3 grits, 150-300µm glass beads, 45-75µm glass beads, 250µm Al powder and 44µm Al powder. The static voltage on the surface of every titanium plate was measured immediately after sandblasting. The static voltages of the titanium plates were recorded and processed using statistical analysis. The results suggested that only sandblasting with 45-75µm glass beads generated a positive charge on titanium, while using all other blasting materials lead to a negative charge. Furthermore, blasting grits of the same powder material but of different sizes might lead to different amount and polarity of the charges. This triboelectric effect is likely to be the main mechanism for charge generation through sandblasting. PMID:24463476

Guo, Cecilia Yan; Hong Tang, Alexander Tin; Hon Tsoi, James Kit; Matinlinna, Jukka Pekka

2014-04-01

77

Characterization of Graphite Coatings Produced by CoBlast™ Technology  

NASA Astrophysics Data System (ADS)

In this article, the surface characterization of graphite-based coatings deposited on metallic substrates at ambient temperature via a modified micro-blasting process technique named CoBlast™ is reported. The coated metals were characterized using scanning electron microscopy, energy-dispersive x-ray spectroscopy, x-ray diffractometer, and x-ray photoelectron spectroscopy. Surface roughness and contact angles were also evaluated. The results showed that the coated layer irrespective of the substrate type was hydrophobic and consisted of graphite, the grit material, and surface oxides, while surface roughness values varied from one substrate to the other. Implications of the resulting surface properties in relation to wear and corrosion applications are highlighted.

Oladoye, A. M.; Carton, J. G.; Olabi, A. G.

2014-04-01

78

Study of the rheological properties and the finishing behavior of abrasive gels in abrasive flow machining  

Microsoft Academic Search

Abrasive flow machining (AFM) is an effective method to finish the smooth surface in the complex holes. Abrasive media are\\u000a key elements which dominate the polished results in AFM. But it is hard to develop the machining model of these abrasive gels\\u000a because of its complicated mechanism. In this research, a non-Newtonian flow is used to set up the abrasive

A. C. Wang; C. H. Liu; K. Z. Liang; S. H. Pai

2007-01-01

79

Ultrasonic assisted magnetic abrasive finishing of hardened AISI 52100 steel using unbonded SiC abrasives  

Microsoft Academic Search

Ultrasonic assisted magnetic abrasive finishing (UAMAF) integrates the use of ultrasonic vibrations and magnetic abrasive finishing (MAF) process to finish surfaces to nanometer order in a relatively short time. The present study emphasizes on the fabrication of UAMAF setup. Using this experimental setup, experimental studies have been carried out with respect to five important process parameters namely supply voltage, abrasive

Rahul S. Mulik; Pulak M. Pandey

2011-01-01

80

Abrasive drill for resilient materials  

NASA Technical Reports Server (NTRS)

Resilient materials normally present problem in obtaining accurate and uniform hole size and position. Tool is fabricated from stiff metal rod such as tungsten or carbon steel that has diameter slightly smaller than required hole. Piercing/centering point is ground on one end of rod. Rod is then plasma-sprayed (flame-sprayed) with suitable hard abrasive coating. High-speed, slow-feed operation of tool is necessary for accurate holes, and this can be done with drill press, hard drill, or similar machines.

Koch, A. J.

1981-01-01

81

21 CFR 872.6030 - Oral cavity abrasive polishing agent.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 false Oral cavity abrasive polishing agent. 872.6030 Section...Devices § 872.6030 Oral cavity abrasive polishing agent. (a) Identification. An oral cavity abrasive polishing agent is a device in...

2010-04-01

82

21 CFR 872.6010 - Abrasive device and accessories.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Abrasive device and accessories. 872.6010...Miscellaneous Devices § 872.6010 Abrasive device and accessories. (a) Identification. An abrasive device and accessories is a device...

2010-04-01

83

Experimental Study of Grit Particle Enhancement in Non-Shock Ignition of PBX 9501  

Microsoft Academic Search

The drop weight impact test is the most commonly used configuration for evaluating sensitivity of explosives to non-shock ignition. Although developed 60 years ago and widely used both as a material compression test and as a test bed for understanding the ignition process itself, little is known about the flow mechanisms or involvement of grit particles as sensitizing agents. In

Paul Peterson

2005-01-01

84

Experimental Study of Grit Particle Enhancement in Non-Shock Ignition  

Microsoft Academic Search

The drop weight impact test is the most commonly used configuration for evaluating sensitivity of explosives to non-shock ignition. Although developed 60 years ago and widely used both as a material compression test and as a test bed for understanding the ignition process itself, little is known about the flow mechanisms or involvement of grit particles as sensitizing agents. In

Richard V. Browning; Paul D. Peterson; Edward L. Roemer; Michael R. Oldenborg; Darla G. Thompson; Racci Deluca

2006-01-01

85

Policy-Based Cognitive Radios David Wilkins, Grit Denker, Mark-Oliver Stehr,  

E-print Network

Policy-Based Cognitive Radios David Wilkins, Grit Denker, Mark-Oliver Stehr, Daniel Elenius, Rukman, and show how this reasoner can be used with various cognitive radios (in this case, an XG radio-defined cognitive radio. Such cog- nitive radios must be able to sense their environment, must be aware of their own

86

TOPOGRAPHIC DESCRIPTION OF ABRASIVE WATERJET MACHINED SURFACES  

E-print Network

) processed by Abrasive Waterjet Machining (AWJM). The design variables were: nozzle diameter, stand-parameter roughness analysis, statistical design of experiments, modeling, Abrasive Waterjet Machining (AWJM industrial AWJM system. The specimens were processed with three different diameters of the nozzle (Nozzle

Aristomenis, Antoniadis

87

Hardfacing and wear plates battle abrasion  

Microsoft Academic Search

This article examines abrasion-resistant steels and hardfacing as two effective weapons at the disposal of material handlers. It points out that abrasion is probably the single most destructive form of wear in the mixing and processing of coal. Particulate matter such as quartz sand and other minerals including coal curtail in-service life of dragline buckets, chute, crusher rolls, gates and

1983-01-01

88

Ultrasonic Abrasive Removal Of EDM Recast  

NASA Technical Reports Server (NTRS)

Ultrasonic abrasive process removes layer of recast material generated during electrical-discharge machining (EDM) of damper pocket on turbine blade. Form-fitted tool vibrated ultrasonically in damper pocket from which material removed. Vibrations activate abrasive in pocket. Amount of material removed controlled precisely.

Mandel, Johnny L.; Jacobson, Marlowe S.

1990-01-01

89

Ceramic-bonded abrasive grinding tools  

DOEpatents

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.

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

1994-11-22

90

Parametric study of magnetic abrasive finishing process  

Microsoft Academic Search

In the present investigation on magnetic abrasive finishing (MAF) process, Taguchi design of experiments is applied to find out important parameters influencing the surface quality generated. Important parameters influencing the surface quality generated during the MAF are identified as: (i) voltage (DC) applied to the electromagnet, (ii) working gap, (iii) rotational speed of the magnet, and (iv) abrasive size (mesh

Dhirendra K. Singh; V. K. Jain; V. Raghuram

2004-01-01

91

Abrasive wear of particle-filled polymers  

Microsoft Academic Search

The abrasive wear rates of quartz and glass particle-reinforced PMMA have been measured as a function of filler volume fraction for silicon carbide, quartz and calcite abrasives. The wear rates were found to exceed those predicted by a simple series model. Abraded surfaces were studied by surface profile measurement and SEM. The excess wear is attributed to rapid wear of

S. V. Prasad; P. D. Calvert

1980-01-01

92

Investigation of two-body abrasive wear  

Microsoft Academic Search

An investigation of two-body abrasive wear utilizing a pin specimen on a rotating SiC particle abrasive paper test device is described. The test materials were 7075 aluminum and 4340 steel which were thermally treated to attain a range of hardness, fracture toughness and yield strength values. Wear resistance is seen to correlate directly with hardness and yield strength for both

H. H. Hirano; A. V. Levy

1978-01-01

93

Abrasive flow machining of turbine engine components  

Microsoft Academic Search

A technique used for improving the performance and durability of aircraft turbine engines by flowing abrasive media through critical components is described. The process is abrasive only where the flow is restricted: the extrusion area (the process is also known as extrusion honing). Process parameters including extrusion pressure and the volume of flow are presented, and the tooling and media

Rhoades

1990-01-01

94

Ceramic-bonded abrasive grinding tools  

SciTech Connect

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.

Holcombe, Jr., Cressie E. (Farragut, TN); Gorin, Andrew H. (Knoxville, TN); Seals, Roland D. (Oak Ridge, TN)

1994-01-01

95

Effects of the diamond grit sizes of the commercial dental diamond points on the weight-load cutting of bovine enamel and glass-ceramic Typodont teeth.  

PubMed

To evaluate the effect of the diamond grit size of commercial dental diamond points on the dental cutting, we conducted weight-load cutting tests on bovine enamel and glass-ceramic typodont teeth using 3 different diamond grit sizes and air-bearing and ball-bearing air-turbine driven handpieces. With the transverse load applied on the diamond point varied between 20 and 80 g, we measured rotational cutting speed and cutting volume. Generally, increases in applied load caused decreases in rotational cutting speed and increases in cutting volume. The intensity of this trend, however, differed between grit sizes. Regular grit diamond points most strongly showed this tendency, while super-fine grit diamond points were least affected. Fine grit diamond points behaved in a manner similar to regular grit points. PMID:1966019

Taira, M; Wakasa, K; Yamaki, M; Matsui, A

1990-12-01

96

A new method for measurement of particle abrasivity  

Microsoft Academic Search

A modified micro-scale abrasive wear test has been used to study the abrasivity of a range of silica and calcium carbonate abrasives in aqueous slurries, against polymethylmethacrylate (PMMA) samples. The method involves the rotation of a cylindrical disc against the specimen surface in the presence of small abrasive particles, and generates a wear scar with an imposed geometry. It allows

D. A. Kelly; I. M. Hutchings

2001-01-01

97

Tumbling mill steel media abrasion wear test development  

Microsoft Academic Search

The goal of this paper is to propose, build and test an abrasion apparatus that will allow the investigation of tumbling mill steel media abrasive friction and wear as a function of the energies\\/forces acting in abrasion in a given mill. The following development is based on the possibility of estimating energy\\/force spectra in abrasion by using a discrete element

Peter Radziszewski; Rena Varadi; Tapiwa Chenje; Lena Santella; Anthony Sciannamblo

2005-01-01

98

Improvement of work surface finish by magnetic abrasive machining  

Microsoft Academic Search

This paper deals with the experimental investigations conducted with magnetic abrasive powder in Magnetic Abrasive Machining. This experimental study is concerned with the experimental setup, development of equipment and detailed experimental investigations for the improvement of work surface finish by Magnetic Abrasive Machining. Experiments were conducted on heat treated stainless steel (AISI 440C) material with silicon carbide as magnetic abrasive.

P. Jayakumar; N. R. Babu; V. Radhakrishnan

1998-01-01

99

Design and simulation for mico-hole abrasive flow machining  

Microsoft Academic Search

Abrasive flow machining technology has become an effective way for micro-hole precise machining. In this paper, we design an equipment for abrasive flow machining to achieve precise machining for peculiar parts. The Fluent, fluid dynamics software, is used here to simulate the abrasive flow micro-hole processing state. We can achieve an ideal machining program for abrasive flow through comparative analysis

Junye Li; Weina Liu; Lifeng Yang; Chun Li; Bin Liu; Haihong Wu; Xiaoli Sun

2009-01-01

100

The abrasion and impact-abrasion behavior of austempered ductile irons  

SciTech Connect

Austempering of ductile irons has led to a new class of irons, Austempered Ductile Irons (ADIs), with improved mechanical strength and fracture toughness lacking in gray cast irons. Laboratory wear tests have been used to evaluate the abrasive and impact-abrasive wear behavior of a suite of ADIs. The use of high-stress, two-body abrasion, low-stress, three-body abrasion, and impact-abrasion tests provides a clear picture of the abrasive wear behavior of the ADIs and the mechanisms of material removal. When combined with hardness measurements, fracture toughness and a knowledge of the microstructure of the ADIs, the overall performance can be assessed relative to more wear resistant materials such as martensitic steels and high-chromium white cast irons

Hawk, Jeffrey A.; Dogan, Omer N.; Lerner, Y.S. (University of Northern Iowa)

1998-01-01

101

Structural blast design  

E-print Network

Blast design is a necessary part of design for more buildings in the United States. Blast design is no longer limited to underground shelters and sensitive military sites, buildings used by the general public daily must ...

Kieval, Tamar S. (Tamar Shoshana), 1980-

2004-01-01

102

New iron-based SiC spherical composite magnetic abrasive for magnetic abrasive finishing  

NASA Astrophysics Data System (ADS)

SiC magnetic abrasive is used to polish surfaces of precise, complex parts which are hard, brittle and highly corrosion-resistant in magnetic abrasive finishing(MAF). Various techniques are employed to produce this magnetic abrasive, but few can meet production demands because they are usually time-consuming, complex with high cost, and the magnetic abrasives made by these techniques have irregular shape and low bonding strength that result in low processing efficiency and shorter service life. Therefore, an attempt is made by combining gas atomization and rapid solidification to fabricate a new iron-based SiC spherical composite magnetic abrasive. The experimental system to prepare this new magnetic abrasive is constructed according to the characteristics of gas atomization and rapid solidification process and the performance requirements of magnetic abrasive. The new iron-based SiC spherical composite magnetic abrasive is prepared successfully when the machining parameters and the composition proportion of the raw materials are controlled properly. Its morphology, microstructure, phase composition are characterized by scanning electron microscope(SEM) and X-ray diffraction(XRD) analysis. The MAF tests on plate of mold steel S136 are carried out without grinding lubricant to assess the finishing performance and service life of this new SiC magnetic abrasive. The surface roughness( R a) of the plate worked is rapidly reduced to 0.051 ?m from an initial value of 0.372 ?m within 5 min. The MAF test is carried on to find that the service life of this new SiC magnetic abrasive reaches to 155 min. The results indicate that this process presented is feasible to prepare the new SiC magnetic abrasive; and compared with previous magnetic abrasives, the new SiC spherical composite magnetic abrasive has excellent finishing performance, high processing efficiency and longer service life. The presented method to fabricate magnetic abrasive through gas atomization and rapid solidification presented can significantly improve the finishing performance and service life of magnetic abrasive, and provide a more practical approach for large-scale industrial production of magnetic abrasive.

Zhang, Guixiang; Zhao, Yugang; Zhao, Dongbiao; Zuo, Dunwen; Yin, Fengshi

2013-03-01

103

The measurement of abrasive particles velocities in the process of abrasive water jet generation  

NASA Astrophysics Data System (ADS)

An optimization of the design of the abrasive cutting head using the numerical simulation requires gathering as much information about processes occurring in the cutting head as possible. Detailed knowledge of velocities of abrasive particles in the process of abrasive water jet generation is vital for the verification of the numerical model. A method of measurement of abrasive particles at the exit of focusing tube using the FPIV technique was proposed and preliminary tests are described in the paper. Results of analysis of measured velocity fields are presented in the paper.

Zele?ák, Michal; Foldyna, Josef; ?íha, Zden?k

2014-08-01

104

Impact-abrasion and abrasion of WC-Co: wear mechanisms in severe environments  

SciTech Connect

Hard and super-hard materials have very good abrasive wear resistance. However, in many severe wear environments that make use of these materials, impact is a significant component of that environment. Consequently, the behavior of many of these hard materials in impact-wear conditions need to be understood with respect to the mechanisms of material removal such small scale fracture and subsequent crack growth in the carbide. This study details the behavior of several ?hard? materials in abrasion and impact-abrasion focusing on the mechanisms of material removal due to impact and abrasion.

Hawk, Jeffrey A.; Wilson, Rick D.; Osara, K. (Outokumpu Research Oy)

2003-10-01

105

Abrasive flow machining of turbine engine components  

SciTech Connect

A technique used for improving the performance and durability of aircraft turbine engines by flowing abrasive media through critical components is described. The process is abrasive only where the flow is restricted: the extrusion area (the process is also known as extrusion honing). Process parameters including extrusion pressure and the volume of flow are presented, and the tooling and media are covered. The abrasive grains are mostly made of silicon carbide, although boron carbide, aluminum oxide, and diamond may also be used. Some abrasive-flow machining applications in aerospace involve removal of the thermal recast layer in the lasered cooling holes of blades and disks, deburring fuel spray nozzles, and polishing cast surfaces of blades, compressor wheels, and impellers. 6 refs.

Rhoades, L.J. (Extrude Hone Corp., Irwin, PA (USA))

1990-01-01

106

Geothermal Energy Market Study on the Atlantic Coastal Plain. GRITS (Version 9): Model Description and User's Guide  

SciTech Connect

The Geothermal Resource Interactive Temporal Simulation (GRITS) model calculates the cost and revenue streams for the lifetime of a project that utilizes low to moderate temperature geothermal resources. With these estimates, the net present value of the project is determined. The GRITS model allows preliminary economic evaluations of direct-use applications of geothermal energy under a wide range of resource, demand, and financial conditions, some of which change over the lifetime of the project.

Kroll, Peter; Kane, Sally Minch [eds.

1982-04-01

107

Abrasion by aeolian particles: Earth and Mars  

NASA Technical Reports Server (NTRS)

Estimation of the rate of aeolian abrasion of rocks on Mars requires knowledge of: (1) particle flux, (2) susceptibilities to abrasion of various rocks, and (3) wind frequencies on Mars. Fluxes and susceptibilities for a wide range of conditions were obtained in the laboratory and combined with wind data from the Viking meteorology experiment. Assuming an abundant supply of sand-sized particles, estimated rates range up to 2.1 x 10 to the minus 2 power cm of abrasion per year in the vicinity of Viking Lander 1. This rate is orders of magnitude too great to be in agreement with the inferred age of the surface based on models of impact crater flux. The discrepancy in the estimated rate of abrasion and the presumed old age of the surface cannot be explained easily by changes in climate or exhumation of ancient surfaces. The primary reason is thought to be related to the agents of abrasion. At least some sand-sized (approx. 100 micrometers) grains appear to be present, as inferred from both lander and orbiter observations. High rates of abrasion occur for all experimental cases involving sands of quartz, basalt, or ash. However, previous studies have shown that sand is quickly comminuted to silt- and clay-sized grains in the martian aeolian regime. Experiments also show that these fine grains are electrostatically charged and bond together as sand-sized aggregates. Laboratory simulations of wind abrasion involving aggregates show that at impact velocities capable of destroying sand, aggregates from a protective veneer on the target surface and can give rise to extremely low abrasion rates.

Greeley, R.; Marshall, J. R.; White, B. R.; Pollack, J. B.; Marshall, J.; Krinsley, D.

1984-01-01

108

Experimental investigations into abrasive flow machining (AFM)  

Microsoft Academic Search

A new non-traditional finishing process known as abrasive flow machining (AFM) is used to deburr, radius, polish and remove recast layer of components in a wide range of applications. The process is relatively new, although around 2000 machines are in use worldwide. Material is removed from the workpiece by flowing a semisolid visco-elastic\\/visco-plastic abrasive-laden medium across the surface to be

V. K. Jain; S. G. Adsul

2000-01-01

109

On the Background Rate in the LXeGRIT Instrument during the 2000 Balloon Flight  

E-print Network

LXeGRIT is the first prototype of a novel Compton telescope for MeV gamma-ray astrophysics based on a Liquid Xenon Time Projection Chamber (LXeTPC), sensitive in the energy band of 0.15-10 MeV. In this homogeneous, 3D position sensitive detector, gamma rays with at least two interactions in the sensitive volume of 2800 cm$^{3}$, are imaged as in a standard Compton telescope. Gamma-rays with a single interaction cannot be imaged and constitute a background which can be easily identified and rejected. Charged particles and localized beta-particles background is also easily suppressed based on the TPC localization capability with millimeter resolution. A measurement of the total gamma-ray background rate in near space conditions and the background rejection power of the LXeTPC was a primary goal of the LXeGRIT balloon flight program. We present here a preliminary analysis addressing this question, based on balloon flight data acquired during the Oct 4-5, 2000 LXeGRIT balloon flight from Ft. Sumner, NM. In this long duration (27 hr) balloon experiment, the LXeGRIT TPC was not surrounded by any gamma-ray or charged particle shield. Single site events and charged particles were mostly rejected on-line at the first and second trigger level. The remaining count rate of single-site \\g-ray events, at an average atmospheric depth of 3.2 g cm$^{-2}$, is consistent with that expected from atmospheric and diffuse gamma-ray background, taking into account the instrument mass model and response.

A. Curioni; E. Aprile; K. L. Giboni; M. Kobayashi; U. G. Oberlack; E. L. Chupp; P. P. Dunphy; T. Doke; J. Kikuchi; S. Ventura

2002-11-27

110

[The application of air abrasion in dentistry].  

PubMed

One of the main objectives of contemporary dentistry is to preserve healthy tooth structure by applying techniques of noninvasive treatment. Air abrasion is a minimally invasive nonmechanical technique of tooth preparation that uses kinetic energy to remove carious tooth structure. A powerful narrow stream of moving aluminum-oxide particles hit the tooth surface and they abrade it without heat, vibration or noise. Variables that affect speed of cutting include air pressure, particle size, powder flow, tip's size, angle and distance from the tooth. It has been proposed that air abrasion can be used to diagnose early occlusal-surface lesions and treat them with minimal tooth preparation using magnifier. Reported advantages of air abrasion include reduced noise, vibration and sensitivity. Air abrasion cavity preparations have more rounded internal contours than those prepared with straight burs. This may increase the longevity of placed restorations because it reduces the incidence of fractures and a consequence of decreased internal stresses. However, air abrasion cannot be used for all patients, i.e. in cases involving severe dust allergy, asthma, chronic obstructive lung disease, recent extraction or other oral surgery, open wounds, advanced periodontal disease, recent placement of orthodontic appliances and oral abrasions, or subgingival caries removal. Many of these conditions increase the risk of air embolism in the oral soft tissues. Dust control is a challenge, and it necessitates the use of rubber dam, high-volume evacuation, protective masks and safety eyewear for both the patient and the therapist. PMID:24684041

Mandini?, Zoran; Vuli?evi?, Zoran R; Beloica, Milos; Radovi?, Ivana; Mandi?, Jelena; Carevi?, Momir; Teki?, Jasmina

2014-01-01

111

The grit effect: predicting retention in the military, the workplace, school and marriage  

PubMed Central

Remaining committed to goals is necessary (albeit not sufficient) to attaining them, but very little is known about domain-general individual differences that contribute to sustained goal commitment. The current investigation examines the association between grit, defined as passion and perseverance for long-term goals, other individual difference variables, and retention in four different contexts: the military, workplace sales, high school, and marriage. Grit predicted retention over and beyond established context-specific predictors of retention (e.g., intelligence, physical aptitude, Big Five personality traits, job tenure) and demographic variables in each setting. Grittier soldiers were more likely to complete an Army Special Operations Forces (ARSOF) selection course, grittier sales employees were more likely to keep their jobs, grittier students were more likely to graduate from high school, and grittier men were more likely to stay married. The relative predictive validity of grit compared to other traditional predictors of retention is examined in each of the four studies. These findings suggest that in addition to domain-specific influences, there may be domain-general individual differences which influence commitment to diverse life goals over time. PMID:24550863

Eskreis-Winkler, Lauren; Shulman, Elizabeth P.; Beal, Scott A.; Duckworth, Angela L.

2013-01-01

112

The grit effect: predicting retention in the military, the workplace, school and marriage.  

PubMed

Remaining committed to goals is necessary (albeit not sufficient) to attaining them, but very little is known about domain-general individual differences that contribute to sustained goal commitment. The current investigation examines the association between grit, defined as passion and perseverance for long-term goals, other individual difference variables, and retention in four different contexts: the military, workplace sales, high school, and marriage. Grit predicted retention over and beyond established context-specific predictors of retention (e.g., intelligence, physical aptitude, Big Five personality traits, job tenure) and demographic variables in each setting. Grittier soldiers were more likely to complete an Army Special Operations Forces (ARSOF) selection course, grittier sales employees were more likely to keep their jobs, grittier students were more likely to graduate from high school, and grittier men were more likely to stay married. The relative predictive validity of grit compared to other traditional predictors of retention is examined in each of the four studies. These findings suggest that in addition to domain-specific influences, there may be domain-general individual differences which influence commitment to diverse life goals over time. PMID:24550863

Eskreis-Winkler, Lauren; Shulman, Elizabeth P; Beal, Scott A; Duckworth, Angela L

2014-01-01

113

Rock blasting environmental impacts  

SciTech Connect

The rock blasting environmental impacts such as: flyrock, ground vibrations, air-blast, and/or noise, dust and fumes are identified and mentioned. Some comments on the correction factors that might be taken into consideration to calculate the initial velocity and the maximum projection of the rock fragments are mentioned as well. The blast fumes causes, its alleviation and protective measures are identified, described and discussed. To mitigate, minimize and/or avoid blast fumes, the AN/FO, Al/AN/FO and S/AN/FO dry blasting agents optimum equations are developed, discussed and recommended.

Agreda, C. [Peruvian Mining Research Co., Lima (Peru)

1995-12-31

114

Modern BLAST Programs  

NASA Astrophysics Data System (ADS)

The Basic Local Alignment Search Tool (BLAST) is arguably the most widely used program in bioinformatics. By sacrificing sensitivity for speed, it makes sequence comparison practical on huge sequence databases currently available. The original version of BLAST was developed in 1990. Since then it has spawned a variant of specialized programs. This chapter surveys the development of BLAST and BLAST-like programs for homology search, discusses alignment statistics that are used in assessment of reported matches in BLAST, and provides the reader with guidance to select appropriate programs and set proper parameters to match research requirements.

Ma, Jian; Zhang, Louxin

115

Characterisation of surface abrasivity and its relation to two-body abrasive wear  

Microsoft Academic Search

In this paper a new method for numerical characterisation of the abrasivity of surfaces and relating this to two-body abrasive wear is described. In a previous work particle angularity was characterised by a newly developed numerical parameter, the quadratic spike parameter (SPQ-particles), which approximates the major protrusions of a particle by fitting quadratic functions to sections of a particle boundary.

M. G Hamblin; G. W Stachowiak

1997-01-01

116

Porcine head response to blast  

E-print Network

Recent studies have shown an increase in the frequency of traumatic brain injuries related to blast exposure. However, the mechanisms that cause blast neurotrauma are unknown. Blast neurotrauma research using computational ...

Nyein, Michelle K.

117

Universal scaling relations for pebble abrasion  

NASA Astrophysics Data System (ADS)

The process of abrasion of gravel in bed load transport results from particle-to-particle collisions, where the energy involved is sufficient to cause chipping and spallation but not fragmentation of parent grains. The removed rock material is not infinitesimal; daughter products as large as coarse sand can be produced. Although previous work has shown that lithology, grain shape, and energy of collision are contributing factors that control abrasion rates of river-bed material, little is known regarding the relationship between these factors and diminution rates. Here we explicitly isolate and investigate how these three factors influence rates of abrasion and the size distribution of daughter products, with laboratory experiments. The apparatus is a double pendulum (Newton's cradle) that produces well-controlled binary collisions. A high-speed camera precisely measures collision energy, while mass of parent rocks. and the size and shape distributions of daughter products, are measured periodically. We examined abrasion of initially square-cut 'rocks' as they underwent successive collisions in the binary collision apparatus. We have examined mass loss rate for varied lithologies, and observe a similar power-law relationship between impact energy and mass abraded. When normalized by sensible material properties, mass loss curves for all materials collapse onto a single curve, suggesting that the underlying mechanics of abrasion for different materials are the same. The relationship does not display the linear trend expected from pure energetics, and we suggest that this is a shape effect as protruding - and hence easily eroded - corners are worn away. Analysis of daughter-product particle size distributions for different lithology fragments - including natural rocks and also bricks - show the same functional form. Surprisingly, it is the power-law relation expected for brittle materials undergoing fragmentation. This suggests that brittle fracture theory also describes the abrasion of river sediments, albeit over a limited length scale that may be associated with skin depth over which collision energy is attenuated. If these results are general, they may be used to search for the signature of abrasion in size distributions of sand and silt particles in natural streams. The apparent universality of both mass loss curves and particle size distributions is in need of theoretical investigation to better understand the underlying mechanics. However, the results are already proving useful for interpreting the role of in-stream abrasion in downstream fining and the production of sand in field studies.

Litwin, K. L.; Jerolmack, D. J.

2012-12-01

118

Directed Relativistic Blast Wave  

E-print Network

A spherically symmetrical ultra-relativistic blast wave is not an attractor of a generic asymmetric explosion. Spherical symmetry is reached only by the time the blast wave slows down to non-relativistic velocities, when the Sedov-Taylor-von Neumann attractor solution sets in. We show however, that a directed relativistic explosion, with the explosion momentum close to the explosion energy, produces a blast wave with a universal intermediate asymptotic -- a selfsimilar directed ultra-relativistic blast wave. This universality might be of interest for the astrophysics of gamma-ray burst afterglows.

Andrei Gruzinov

2007-04-23

119

A method of motion control about micro-hole abrasive flow machining based on Delphi language  

Microsoft Academic Search

This paper presents the techniques about microhole abrasive flow machining techniques of the abrasive flow machining crafts through controlling the relative motion between the workpiece and the abrasive flow by controlling motion speed of the abrasive cylinder piston, and improving machining accuracy and efficiency. Abrasive flow maching through motor-driven the abrasive cylinder piston is achieved through using computer's information processing

Junye Li; Weina Liu; Lifeng Yang; Chunlin Tian; Shuren Zhang

2009-01-01

120

ABRASIVE-BASED NANO-FINISHING TECHNIQUES: AN OVERVIEW  

Microsoft Academic Search

The surface finishing techniques can be divided into two categories: traditional and advanced. To overcome some of the problems of traditional finishing techniques, hybridized processes have been evolved by the researchers. Some of the advanced finishing processes that have been reviewed are abrasive flow machining (AFM), magnetorheological finishing (MRF), magnetorheological abrasive flow finishing (MRAFF), magnetic abrasive finishing (MAF), chemo mechanical

V. K. Jain

2008-01-01

121

Research of magnetic abrasive prepared by hot pressing sintering process  

Microsoft Academic Search

As a kind of precise surface finishing technology, magnetic abrasive finishing has wide application, low cost, high efficiency, good effects, and other advantages. Magnetic abrasive performance is one main factor affecting finishing effect and efficiency of magnetic abrasive finishing. By experiments, process and parameters of hot pressing sintering preparation are defined, its micro-structure and finishing performance are researched. The results

H. L. Chen; W. H. Li; S. Q. Yang; S. C. Yang

2010-01-01

122

ON THE PERFORMANCE ANALYSIS OF FLEXIBLE MAGNETIC ABRASIVE BRUSH  

Microsoft Academic Search

Magnetic abrasive finishing (MAF) of alloy steel workpiece with unbounded magnetic abrasive particles (UMAPs) indicates that the surface finish in the range of nanometer can be achieved. Important controllable four process parameters have been identified which are as current to the electromagnet, machining gap, abrasive size (mesh number), and number of cycles. Experiments have been planned using design of experiments

Dhirendra K. Singh; V. K. Jain; V. Raghuram

2005-01-01

123

Magnetic field assisted abrasive based micro-\\/nano-finishing  

Microsoft Academic Search

Micro-\\/nano-machining (abbreviated as MNM) processes are classified mainly in two classes: traditional and advanced. Majority of the traditional MNM processes are embedded abrasive or fixed geometry cutting tool type processes. Conversely, majority of the advanced MNM processes are loose flowing abrasive based processes in which abrasive orientation and its geometry at the time of interaction with the workpiece is not

V. K. Jain

2009-01-01

124

Analysis of magnetic abrasive finishing with slotted magnetic pole  

Microsoft Academic Search

Magnetic Abrasive Finishing (MAF) is relatively a new finishing process among the advanced finishing processes in which the workpiece is kept in the magnetic field created by two poles of an electromagnet. The working gap between the workpiece and the magnet is filled with magnetic abrasive particles. A flexible magnetic abrasive brush is formed, acting as a multipoint cutting tool,

S. C. Jayswal; V. K. Jain; P. M. Dixit

2004-01-01

125

Modeling and simulation of magnetic abrasive finishing process  

Microsoft Academic Search

Magnetic abrasive finishing (MAF) is one of the advanced finishing processes, which produces a high level of surface quality and is primarily controlled by a magnetic field. In MAF, the workpiece is kept between the two poles of a magnet. The working gap between the workpiece and the magnet is filled with magnetic abrasive particles. A magnetic abrasive flexible brush

S. C. Jayswal; V. K. Jain; P. M. Dixit

2005-01-01

126

Lateral Crack in Abrasive Wear of Brittle Materials  

Microsoft Academic Search

An analytical model for lateral cracks occurring in abrasive wear of brittle materials was developed. The stress field around the lateral crack and the stress intensity factor at the crack tip were analytically modeled. The abrasive wear by abrasive particles was experimentally studied by sliding indentation. In soda-lime glass, it was observed that chipping by the lateral crack occurred and

Yoomin Ahn; Nahm-Gyoo Cho; Seoung-Hwan Lee; Dohyung Lee

2003-01-01

127

Simulation of surface generated in abrasive flow machining process  

Microsoft Academic Search

For the control of abrasive flow machining (AFM) process, it is important to understand the mechanics of generation of its surface profile. This paper describes the analysis and simulation of profile of finished surface and material removal by the interaction of abrasive grains with workpiece. The abrasive grains are randomly distributed in media depending upon their percentage concentration and mesh

Rajendra Kumar Jain; Vijay Kumar Jain

1999-01-01

128

Surface Roughness of Carbides Produced by Abrasive Water Jet Machining  

Microsoft Academic Search

This study presents the effect of jet pressure, abrasive flow rate and work feed rate on smoothness of the surface produced by abrasive water jet machining of carbide of grade P25. Carbide of grade P25 is very hard and cannot be machined by conventional techniques. Cutting was performed on a water jet machine model WJ 4080. The abrasive used in

Ahsan Ali Khan; Mohd Efendee Bin Awang; Ahmad Azwari Bin Annuar

2005-01-01

129

Developing the polymer abrasive gels in AFM processs  

Microsoft Academic Search

Abrasive flow machining (AFM) has excellent polishing effect in complex holes cut by wire electrical discharge machining (WEDM). The recast layers produced by WEDM can be removed when the abrasive media passes through the complex hole. Therefore, the media are the key elements that dominate the polishing behavior in AFM. However, commercial abrasive media are very expensive, and not every

A. C. Wang; S. H. Weng

2007-01-01

130

Grinding Wheel Abrasive Material Selection Using Fuzzy TOPSIS Method  

Microsoft Academic Search

The efficiency of a grinding wheel and quality of surface finish of the machined component mainly depend on the type of abrasive material, abrasive grain size, bonding material, wheel grade and wheel structure. Modern grinding wheels use various types of abrasive materials, ranging from aluminum oxide to partially stabilized zirconia, and also superabrasive materials, like cubic boron nitride and diamond.

Saikat Ranjan Maity; Shankar Chakraborty

2012-01-01

131

The friction and wear of metals and binary alloys in contact with an abrasive grit of single-crystal silicon carbide  

NASA Technical Reports Server (NTRS)

Sliding friction experiments were conducted with various metals and iron-base binary alloys (alloying elements Ti, Cr, Mn, Ni, Rh and W) in contact with single crystal silicon carbide riders. Results indicate that the friction force in the plowing of metal and the groove height (corresponding to the wear volume of the groove) decrease linearly as the shear strength of the bulk metal increases. The coefficient of friction and groove height generally decrease, and the contact pressure increases with an increase in solute content of binary alloys. There appears to be very good correlation of the solute to iron atomic ratio with the decreasing rate of change of coefficient of friction, the decreasing rate of change of groove height and the increasing rate of change of contact pressure with increasing solute content. These rates of change increase as the solute to iron atomic radius ratio increases or decreases from unity.

Miyoshi, K.; Buckley, D. H.

1979-01-01

132

Friction and wear of metals with a single-crystal abrasive grit of silicon carbide: Effect of shear strength of metal  

NASA Technical Reports Server (NTRS)

Sliding friction experiments were conducted with spherical, single-crystal silicon carbide riders in contact with various metals and with metal riders in contact with silicon carbide flats. Results indicate that: (1) the friction force in the plowing of metal and (2) the groove height (corresponding to the volume of the groove) are related to the shear strength of the metal. That is, they decrease linearly as the shear strength of the bulk metal increases. Grooves are formed in metals primarily from plastic deformation, with occasional metal removal. The relation between the groove width D and the load W can be expressed by W = kD, superscript n which satisfies Meyer's law.

Miyoshi, K.; Buckley, D. H.

1978-01-01

133

The friction and wear of metals and binary alloys in contact with an abrasive grit of single-crystal silicon carbide  

NASA Technical Reports Server (NTRS)

Sliding friction experiments were conducted with various metals and iron-base binary alloys (alloying elements Ti, Cr, Mn, Ni, Rh, and W) in contact with single-crystal silicon carbide riders. Results indicate that the coefficient of friction and groove height (corresponding to the wear volume) decrease linearly as the shear strength of the bulk metal increases. The coefficient of friction and groove height generally decrease with an increase in solute content of binary alloys. A separate correlation exists between the solute to iron atomic radius ratio and the decreasing rates of change of coefficient of friction and groove height with increasing solute content. These rates of change are minimum at a solute to iron radius ratio of unity. They increase as the atomic ratio increases or decreases linearly from unity. The correlations indicate that atomic size is an important parameter in controlling friction and wear of alloys.

Miyoshi, K.; Buckley, D. H.

1979-01-01

134

Lightweighting large optics with abrasive waterjets  

Microsoft Academic Search

A new approach to lightweighting large optics using the abrasive waterjet (AWJ) milling process has been developed and has demonstrated that significant weight reductions in glass face sheets can be achieved. The AWJ glass milling process has been developed to offer a safe and low cost machining alternative over conventional methods that are considered a high risk machining process. The

Peter J. Miles

1998-01-01

135

Machining time estimation for magnetic abrasive processes  

Microsoft Academic Search

Here we present the magnetic abrasive process which is used to finish and size those workpieces that have been produced using standard machine tools. The process is proved to be very effective in achieving the desired finish size and roundness of the workpieces. We develop an empirical expression to estimate the machining time to produce a workpiece with specified roundness.

G. Z. KREMEN; E. A. ELSAYED; J. L. RIBEIRO

1994-01-01

136

Abrasive wear behaviour of austempered ductile iron  

Microsoft Academic Search

This paper presents a study of the abrasive wear behaviour of austempered ductile irons (ADI’s) with dual matrix structures under different conditions. The wear resistance model was developed based on the type of the material, applied load and sliding distance. The orthogonal array and analysis of variance were employed to find out which design parameters significantly affect the quality characteristic.

Y. Sahin; O. Durak

2007-01-01

137

Abrasive Flow Polishing of Micro Bores  

Microsoft Academic Search

Micro bore finishing for metal and ceramic materials has been a challenge in the manufacturing industry. Unfortunately, little is understood about how to polish a micro bore and how to assess its inner wall quality because it is difficult to access the micro bore for either polishing or measurement. This article reports on a feasibility study of the abrasive flow

Ling Yin; Kuppuswamy Ramesh; Stephen Wan; Xiang Dong Liu; Han Huang; Yu Chan Liu

2004-01-01

138

Neural Network Modeling of Abrasive Flow Machining  

Microsoft Academic Search

This paper discusses the preliminary development of a neural network-based process monitor and off-line controller for abrasive flow machining of automotive engine intake manifolds. The process is only observable indirectly, yet the time at which machining achieves the specified air flow rate must be estimated accurately. A neural network model is used to estimate when the process has achieved air

Alice E. Smith; William S. Slaughter

139

Development of magneto abrasive flow machining process  

Microsoft Academic Search

Abrasive flow machining (AFM) is a relatively new process among non-conventional machining processes. Low material removal rate happens to be one serious limitation of almost all such processes. Limited efforts have hitherto been directed towards improving the efficiency of these processes so as to achieve higher material removal rates by applying different techniques. This paper discusses the possible improvement in

Sehijpal Singh; H. S. Shan

2002-01-01

140

Pipeline abrasion coatings survive extended bottom tow  

Microsoft Academic Search

Pipeline bottom-tow tests for Placid Oil Co.'s Green Canyon Block 29 (Gulf of Mexico) project have supported the technical feasibility of applying abrasion coatings that will survive bottom towing over distances greater than 450 nautical miles. The tests were completed off the Texas Coast in June of last year by R. J. Brown and Associates of America Inc. (RJBA), Houston.

1987-01-01

141

Dependence of microscale abrasion mechanisms of WC-Co hardmetals on abrasive type  

Microsoft Academic Search

Sintered WC-Co hardmetals are employed as wear resistant materials in a wide variety of applications, some of which require resistance to abrasive wear. Such materials usually contain WC particles of less than 10?m in size. Assessment of wear resistance is often made with tests such as those described in the ASTM standards G65 and B611 both of which employ abrasive

P. H. Shipway; J. J. Hogg

2005-01-01

142

Abrasion and erosion of hard materials related to wear in the abrasive waterjet  

Microsoft Academic Search

Three hard materials, tungsten carbide\\/cobalt, boron carbide, and composite carbide, which are commonly used for the mixing tube in the abrasive waterjet application, were compared using three different ASTM abrasion and erosion tests: ASTM G76, ASTM G65 and ASTM B611. Relative results were compared in terms of hardness and toughness of the materials. Over the range of conditions represented by

Eric Ness; Ron Zibbell

1996-01-01

143

Abrasive wear behaviour of electrodeposited nanocrystalline materials  

NASA Astrophysics Data System (ADS)

The effect of grain size refinement on the abrasive wear behaviour of nanocrystalline Ni, Ni-P and Co electrodeposits and the critical materials properties that influence the abrasive wear resistance were studied using the Taber wear test. As the grain size of Ni decreased from 90 mum to 13 nm, the dominant abrasive wear mode changed from ploughing to cutting and the Taber wear resistance was considerably improved by the increases in hardness and surface elastic properties. The abrasive wear behaviour of Ni with various grain sizes can be described using the attack angle model, which takes into consideration the randomly dispersed Al2O3 abrasive particles in the Taber wheel with various sizes, shapes and orientations. Depending on the phosphorus content, the nickel-phosphorus (Ni-P) alloys containing up to 6 wt.% P had nanocrystalline or mixed nanocrystalline-amorphous structures and both regular and inverse Hall-Petch behaviour were observed as a result of the microstructural changes with increasing P content/decreasing grain size. The wear resistance, like hardness, followed the Hall-Petch type behaviour, demonstrating that the smallest grain size does not necessarily provide the best wear resistance. For all Ni-P alloys, the wear resistance was improved by heat treatment due to Ni3P precipitates and, for materials with high P content, nanocrystallization of the amorphous phase. For heat-treated Ni-P alloys, however, the highest hardness did not give the best wear resistance. Despite the grain size reduction of Co from 10 mum to 17 nm, there was no significant change in the wear resistance due to the unusually high degree of plastic deformation of the nanocrystalline material. In addition to hardness and surface elastic properties which are usually considered important material properties that control the abrasive wear resistance, Taber wear ductility was introduced as a new material intrinsic property which can be applied to explain abrasive wear resistance for cases when the former two parameters are poor indicators such as for heat-treated Ni-P with high P content and nanocrystalline Co. The results of this study have shown that both nanocrystalline Ni and Ni-P coatings could be of significant technological importance in the area of wear resistant coatings.

Jeong, Daehyun

144

Abrasive wear properties of tool steel matrix composites in rubber wheel abrasion test and laboratory cone crusher experiments  

Microsoft Academic Search

Abrasive wear is the most common type of wear phenomenon in mineral crushing industry. Tool steel matrix-based composites are an attractive choice to combat wear in those conditions because of their excellent abrasion resistance. One purpose of this study is to evaluate the abrasion resistance of such composites having different microstructures. Another purpose is to find out whether the simple

Sanna Ala-Kleme; Päivi Kivikytö-Reponen; Jari Liimatainen; Jussi Hellman; Simo-Pekka Hannula

2007-01-01

145

The LXeGRIT Compton Telescope Prototype: Current Status and Future Prospects  

E-print Network

LXeGRIT is the first prototype of a novel concept of Compton telescope, based on the complete 3-dimensional reconstruction of the sequence of interactions of individual gamma rays in one position sensitive detector. This balloon-borne telescope consists of an unshielded time projection chamber with an active volume of 400 cm$^2 \\times 7$ cm filled with high purity liquid xenon. Four VUV PMTs detect the fast xenon scintillation light signal, providing the event trigger. 124 wires and 4 anodes detect the ionization signals, providing the event spatial coordinates and total energy. In the period 1999 -- 2001, LXeGRIT has been extensively tested both in the laboratory and at balloon altitude, and its response in the MeV region has been thoroughly characterized. Here we summarize some of the results on pre-flight calibration, event reconstruction techniques, and performance during a 27 hour balloon flight on October 4 -- 5. We further present briefly the on-going efforts directed to improve the performance of this prototype towards the requirements for a base module of a next-generation Compton telescope.

E. Aprile; A. Curioni; K. L. Giboni; M. Kobayashi; U. G. Oberlack; E. L. Chupp; P. P. Dunphy; T. Doke; J. Kikuchi; S. Ventura

2002-11-30

146

Blast furnace reactions  

Microsoft Academic Search

Vast a dvances h ave b een m ade in blast-furnace t echnology d uring t he p ast two decades through p lant t rials and plant d evelopments a ssisted by research to provide b etter u nderstanding of physical and chemical w orkings of the blast f urnace. T he f ields of research have i ncluded

E. T. Turkdogan

1978-01-01

147

Toxicology of blast overpressure  

Microsoft Academic Search

Blast overpressure (BOP) or high energy impulse noise, is the sharp instantaneous rise in ambient atmospheric pressure resulting from explosive detonation or firing of weapons. Blasts that were once confined to military and to a lesser extent, occupational settings, are becoming more universal as the civilian population is now increasingly at risk of exposure to BOP from terrorist bombings that

Nabil M. Elsayed

1997-01-01

148

Lightweight blast shield  

DOEpatents

A tandem warhead missile arrangement that has a composite material housing structure with a first warhead mounted at one end and a second warhead mounted near another end of the composite structure with a dome shaped composite material blast shield mounted between the warheads to protect the second warhead from the blast of the first warhead.

Mixon, Larry C. (Madison, AL); Snyder, George W. (Huntsville, AL); Hill, Scott D. (Toney, AL); Johnson, Gregory L. (Decatur, AL); Wlodarski, J. Frank (Huntsville, AL); von Spakovsky, Alexis P. (Huntsville, AL); Emerson, John D. (Arab, AL); Cole, James M. (Huntsville, AL); Tipton, John P. (Huntsville, AL)

1991-01-01

149

Energy components in rock blasting  

Microsoft Academic Search

Ten production blasts and one single-hole confined blast have been monitored in two quarries in order to assess the measurable forms of energy in which the energy delivered by the explosive is transformed in rock blasting. The seismic field from seismographs readings, the initial velocity of the blasted rock face obtained from high-speed video camera records, and the fragment size

José A. Sanchidrián; Pablo Segarra; Lina M. López

2007-01-01

150

Abrasion-Resistant Technology and its Prospect for CFB Boilers  

NASA Astrophysics Data System (ADS)

In recent years, CFB boilers (CFBB) have been widely used in the commercial power plants due to its environmental benefits, high combustion efficiency, wide coal flexibility, and some other advantages. At the same time, the abrasion problem, the greatest weakness of this kind of boiler, has been gradually exposed in its application process. The abrasion, particularly on key parts such as the heating surface of water-cooled wall, furnace corners, separator entrance, seriously restricts the long-period operation ability of the CFBB. This article discusses current development status for various abrasion resistant refractory materials used in a CFBB. Some comments are provided for developing new high-performance abrasion resistant refractory materials and rapid-repaired materials according to the abrasion principle and the abrasion on different parts, as well as the economical and environmental requirements for the material. The abrasion solution and operation period of CFBB can be better improved given realization.

Zheng, H.; Li, Y. J.; Wang, L. J.; Liu, S. H.; Dou, Q. R.

151

Accelerated Erosion Rate of Concrete by Abrasive Jet  

NASA Astrophysics Data System (ADS)

The acceleration ratio of the abrasion tester using water jet with sand was investigated to enable the progress estimation of abrasion which is needed to the asset management. The abrasion test was executed by using specimens taken from the sound part of concrete canals, and the results are compared with the abraded specimens from submerged part of the identical canals. Then, the acceleration ratio was calculated from the service period and the test duration needed to achieve the similar abrasion on the sound specimen. As a result, the acceleration ratio was 1.05-1.72y/h in the case assessing with the abrasion depth, and 0.50-8.85y/h in the case with the unevenness. The progress of abrasion could be estimated by using the calculated acceleration ratio. Moreover, it was confirmed that the unevenness converged at constant value while the abrasion depth kept increasing with service period.

Ueno, Kazuhiro; Natsuka, Isamu; Ishii, Masayuki

152

A Policy Engine For Spectrum Sharing Grit Denker, Daniel Elenius, Rukman Senanayake, Mark-Oliver Stehr, David Wilkins  

E-print Network

A Policy Engine For Spectrum Sharing Grit Denker, Daniel Elenius, Rukman Senanayake, Mark--We argue for a policy-based approach to increase spectrum availability. To this extend, we briefly summarize a new language for expressing policies that allow opportunistic spectrum access. A Policy Reasoner

Wilkins, David E.

153

Wilson Bulletin 116(4):304313, 2004 GRIT-SITE SELECTION OF BLACK BRANT: PARTICLE SIZE OR  

E-print Network

Hwy., Stinson Beach, CA 94970, USA. 3 Current address: Sacramento National Wildlife Refuge, 752 County of calciferous grit (Leopold 1931; McCann 1939, 1961; Dale 1 Waterfowl Ecology Research Group, Dept. of Wildlife nigri- cans) rely on reserves less than other arctic- breeding waterfowl of similar mass (Ankney 1984

Black, Jeff

154

A Guide for Developing Standard Operating Job Procedures for the Grit Removal Process Wastewater Treatment Facility. SOJP No. 2.  

ERIC Educational Resources Information Center

This guide describes standard operating job procedures for the grit removal process of wastewater treatment plants. Step-by-step instructions are given for pre-start up inspection, start-up, continuous operation, and shut-down procedures. A description of the equipment used in the process is given. Some theoretical material is presented. (BB)

Deal, Gerald A.; Montgomery, James A.

155

BLAST+: architecture and applications  

PubMed Central

Background Sequence similarity searching is a very important bioinformatics task. While Basic Local Alignment Search Tool (BLAST) outperforms exact methods through its use of heuristics, the speed of the current BLAST software is suboptimal for very long queries or database sequences. There are also some shortcomings in the user-interface of the current command-line applications. Results We describe features and improvements of rewritten BLAST software and introduce new command-line applications. Long query sequences are broken into chunks for processing, in some cases leading to dramatically shorter run times. For long database sequences, it is possible to retrieve only the relevant parts of the sequence, reducing CPU time and memory usage for searches of short queries against databases of contigs or chromosomes. The program can now retrieve masking information for database sequences from the BLAST databases. A new modular software library can now access subject sequence data from arbitrary data sources. We introduce several new features, including strategy files that allow a user to save and reuse their favorite set of options. The strategy files can be uploaded to and downloaded from the NCBI BLAST web site. Conclusion The new BLAST command-line applications, compared to the current BLAST tools, demonstrate substantial speed improvements for long queries as well as chromosome length database sequences. We have also improved the user interface of the command-line applications. PMID:20003500

2009-01-01

156

New blast weapons.  

PubMed

Over the last decade a large number of weapon systems have appeared that use blast as their primary damage mechanism. This is a notable trend; until recently very few warheads relied on blast as their primary output. Most warheads in service use explosives to drive metal such as fragments and shaped charge jets to engage targets. New technologies are now being integrated into warheads that claim to have enhanced blast performance. Blast weapons could have been designed to fill a gap in capability; they are generally used for the attack of 'soft' targets including personnel, both in the open and within protective structures. With the increased number and range of these weapons, it is likely that UK forces will have to face them in future conflicts. This paper briefly describes fuel-air explosive blast weapons and reviews a range of enhanced blast weapons that have been developed recently. The paper concludes with a brief discussion on the reasons why enhanced blast technologies may be proliferating and how this could affect the Defence Medical Services. PMID:11307681

Dearden, P

2001-02-01

157

Abrasive personality disorder: Definition and diagnosis  

Microsoft Academic Search

This article advances a proposal for a newly identified type of personality disorder. While, like some of the other major\\u000a personality disorders, the abrasive personality disorder (AbPD) shares some features with other Axis II disorders, it may\\u000a however be considered as possessing sufficient idiosyncratic features as to warrant a separate classification. There are few\\u000a documented discussions of this disorder within

Stuart B. Litvak

1994-01-01

158

Design of an impact abrasion testing machine  

Microsoft Academic Search

By using a cam-flat follower-impact shaft with a crank-flat rotating anvil system, the machine to be described can create various impact abrasion conditions to simulate a large range of industrial situations encountered in this field. The main features of the machine are the long working life of the flat rotating anvil, which works in the same way as that of

D. Zhang; P. R. Beeley; A. J. Baker

1994-01-01

159

Abrasive wear of titanium nitride coatings  

Microsoft Academic Search

Titanium nitride thin films, deposited by plasma vapor deposition (PVD) or chemical vapor deposition (CVD), are commonly used on metal cutting tools. The TiN coating increases cutting tool-life and extends the tool operating range. This paper examines the behavior of PVD TiN on high-speed steel (HSS) substrates under low stress abrasion. High-speed steel bars were coated with TiN by a

M. Scholl

1997-01-01

160

Relating contact conditions to abrasive wear  

Microsoft Academic Search

Damage caused by particles within rolling\\/sliding contacts can severely reduce the operational life of machinery such as roller bearings, gears and pumps.Abrasive wear of spherical roller thrust bearings has been studied using a stylus apparatus and scanning electron microscopy (SEM). Both a standard bearing and a bearing with rollers coated with metal mixed amorphous carbon (Me-C:H) were studied. The SEM

R. Nilsson; F. Svahn; U. Olofsson

2006-01-01

161

Abrasive wear of metallic matrix reinforced materials  

Microsoft Academic Search

It is presented an investigation of the abrasive wear behaviour of metallic matrix reinforced materials (MMRMs). Micro-scale wear tests were performed on Fe–Cr–C\\/NbC composite materials with different volume fractions of reinforcement particles, produced by variable powder feed rate laser cladding. The obtained results show that, depending on the conditions on which the wear tests were made, the wear resistance of

R Colaço; R Vilar

2003-01-01

162

Abrasive wear testing of dental restorative materials  

Microsoft Academic Search

A tribometer (model ISC-200PC) was modified to form a pin-on-disk type of wear test apparatus. A dental restorative material specimen was used as the pin and a diamond grinding wheel as the abrasive counterface. Both normal and friction forces were recorded during the course of the test. The volumetric wear rate was calculated from the change of length and cross-sectional

Weiping Wang; Anthony T. DiBenedetto; A. Jon. Goldberg

1998-01-01

163

Mechanism of Abrasive Wear in Nanomachining  

Microsoft Academic Search

In this study, nanomachining is utilized to investigate the abrasive wear mechanism that produces a nano scale groove on a\\u000a bulk material. Two different tools (Berkovich and Conical) with the same tip radius (100 nm) but different edge geometries\\u000a were used for machining both Cu- and Ni-coated materials with a nanoindenter that was equipped with a nano scratching attachment.\\u000a It was

Sumaiya IslamRaafat; Raafat N. Ibrahim

2011-01-01

164

Scratching of polymers—Modeling abrasive wear  

Microsoft Academic Search

This paper aims to model abrasive wear for polymers using single-track and intersecting scratching techniques. Scratch and pin-on-disc wear tests were conducted on five different commercial polymers. Wear debris generated by multiple-pass single-track and intersecting scratching tests were compared and correlated with the specific wear rates of the same polymers in a pin-on-disk test using ground steel surface (Ra=1.34?m) as

Sujeet K. Sinha; W. L. M. Chong; Seh-Chun Lim

2007-01-01

165

Pilot study on binding of bovine salivary proteins to grit silicates and plant phytoliths.  

PubMed

Mostly fed with grass in fresh or conserved form, cattle and other livestock have to cope with silicate defence bodies from plants (phytoliths) and environmental silicates (grit), which abrade tooth enamel and could additionally interact with various salivary proteins. To detect potential candidates for silicate-binding proteins, bovine whole saliva was incubated with grass-derived phytoliths and silicates. Interactions of salivary proteins with pulverized bovine dental enamel and dentine were additionally analysed. After intense washing, the powder fractions were loaded onto 1D-polyacrylamide gels, most prominent adhesive protein bands were cut out and proteins were identified by mass spectrometry within three independent replicates. All materials were mainly bound by bovine odorant-binding protein, bovine salivary protein 30×10(3) and carbonic anhydrase VI. The phytolith/silicate fraction showed additional stronger interaction with haemoglobin ? and lactoperoxidase. Conceivably, the binding of these proteins to the surfaces may contribute to biological processes occurring on them. PMID:23776006

Mau, Marcus; M Kaiser, Thomas; Südekum, Karl-Heinz

2013-06-01

166

A 71-year-old man with anaphylaxis after eating grits  

PubMed Central

The allergist is frequently called on to evaluate patients after episodes of anaphylaxis to determine the cause and implement preventive measures that will reduce the patient’s risk from future episodes. The etiology of anaphylaxis can be the result of numerous causes that may go undiagnosed if a thorough evaluation is not performed. We present a 71-year-old man with no history of food allergy or atopy who presented to the emergency room and then our allergy clinic for evaluation after suffering anaphylaxis after a meal of grits and shrimp. The underlying diagnosis, which was subsequently determined, requires a high index of suspicion and should be included in the differential diagnosis of any patient presenting with unexplained anaphylaxis. PMID:22370536

Posthumus, Jonathon; Borish, Larry

2014-01-01

167

[Blast lung injuries].  

PubMed

In armed conflicts and during terrorist attacks, explosive devices are a major cause of mortality. The lung is one of the organs most sensitive to blasts. Thus, today it is important that every GP at least knows the basics and practices regarding treatment of blast victims. We suggest, following a review of the explosions and an assessment of the current threats, detailing the lung injuries brought about by the explosions and the main treatments currently recommended. PMID:20933166

Clapson, P; Pasquier, P; Perez, J-P; Debien, B

2010-09-01

168

ESF BLAST DESIGN ANALYSIS  

SciTech Connect

The purpose and objective of this design analysis are to develop controls considered necessary and sufficient to implement the requirements for the controlled drilling and blasting excavation of operations support alcoves and test support alcoves in the Exploratory Studies Facility (ESF). The conclusions reached in this analysis will flow down into a construction specification ensuring controlled drilling and blasting excavation will be performed within the bounds established here.

E.F. fitch

1995-03-13

169

Simulation for the prediction of surface roughness in magnetic abrasive flow finishing (MAFF)  

Microsoft Academic Search

The final machining (or finishing) of precision parts with high level of surface finish and close tolerance is making the application of magnetic abrasive finishing technology increasingly important. Magnetic abrasive flow finishing (MAFF) is a new abrasive finishing process combining the features of abrasive flow finishing (AFF) and magnetic abrasive finishing (MAF). MAFF provides a high level of surface finish

Amit M. Wani; Vinod Yadava; Atul Khatri

2007-01-01

170

Abrasion of tungsten carbide hardmetals using hard counterfaces  

Microsoft Academic Search

WC-based hardmetals are materials that are widely used in applications where abrasion resistance is required. This paper describes the results of tests that were performed using both a modified ASTM G65 test rig and an ASTM B611 test rig. The results are used to support the development of a new ISO abrasion wear test.Test parameters investigated included different abrasives (silica

A. J. Gant; M. G. Gee

2006-01-01

171

Abrasion resistance of concrete containing nano-particles for pavement  

Microsoft Academic Search

The abrasion resistance of concrete containing nano-particles for pavement is experimentally studied. Both nano-TiO2 and nano-SiO2 are, respectively, employed to be as the additives. For comparison, the abrasion resistance of plain concrete and the concrete containing polypropylene (PP) fibers is also experimentally studied in this work. The test results indicate that the abrasion resistance of concretes containing nano-particles and PP

Hui Li; Mao-hua Zhang; Jin-ping Ou

2006-01-01

172

The response of isotropic brittle materials to abrasive processes  

SciTech Connect

This paper is an overview of brittle material responses to abrasion. It proposes a 3 region model for both 2-body and 3-body wear, two regions being where removal rate is nearly independent of abrasive size at otherwise identical conditions and a transition region where rate is proportional to abrasive size. The mechanics will be explored through these 3 regions in 2-body and 3-body wear and some comparisons will be made to the wear of nonbrittle materials. 14 refs.

Brown, N.J.; Fuchs, B.A.; Hed, P.P.; Stowers, I.F.

1989-04-24

173

Mathematical model of abrasive wear of high performance concrete  

Microsoft Academic Search

This paper presents a mathematical model for kinetics of abrasive wear of concrete. The underwater method ASTM C1138 was used to test the abrasive wear. The paper includes the results for high performance concrete (HPC) and a description of water\\/cement ratio (w\\/c) influence on the abrasive wear of HPC under constant load. The influence of load on a concrete wear

El?bieta Horszczaruk

2008-01-01

174

Predicting three-body abrasive wear using Monte Carlo methods  

Microsoft Academic Search

Predicting wear of materials under three-body abrasion is a challenging project, since three-body abrasion is more complicated than two-body abrasion. In this paper, a Monte Carlo model for simulating plastic deformation wear rate, i.e. low-cycle fatigue wear rate, is proposed. The Manson–Coffin formula and the Palmgrom–Miner linear accumulated-damage principle were used in the model as well as the Monte Carlo

Liang Fang; Weimin Liu; Daoshan Du; Xiaofeng Zhang; Qunji Xue

2004-01-01

175

Analysis of magnetorheological abrasive flow finishing (MRAFF) process  

Microsoft Academic Search

A new precision finishing process called magnetorheological abrasive flow finishing (MRAFF), which is basically a combination\\u000a of abrasive flow machining (AFM) and magnetorheological finishing (MRF), has been developed for nano-finishing of parts even\\u000a with complicated geometry for a wide range of industrial applications. In this paper microstructure of the mixture of magnetic\\u000a and abrasive particles in magnetorheological polishing fluid (MRPF)

Manas Das; V. K. Jain; P. S. Ghoshdastidar

2008-01-01

176

A new dimension to conservative dentistry: Air abrasion  

PubMed Central

Air abrasion dentistry has evolved over a period of time from a new concept of an alternative means of cavity preparation to an essential means of providing a truly conservative preparation for preservation of a maximal sound tooth structure. The development of bonded restorations in combination with air abrasion dentistry provides a truly minimal intervention dentistry. This article reviews the development of air abrasion, its clinical uses, and the essential accessories required for its use. PMID:20582212

Hegde, Vivek S; Khatavkar, Roheet A

2010-01-01

177

Improvement of work surface finish by magnetic abrasive machining  

NASA Astrophysics Data System (ADS)

This paper deals with the experimental investigations conducted with magnetic abrasive powder in Magnetic Abrasive Machining. This experimental study is concerned with the experimental setup, development of equipment and detailed experimental investigations for the improvement of work surface finish by Magnetic Abrasive Machining. Experiments were conducted on heat treated stainless steel (AISI 440C) material with silicon carbide as magnetic abrasive. By means of Orthogonal Array experimentation, the set of parameters that can improve the workpiece surface finish by at least 50% are selected. The influence of different process parameters apart from the work surface characteristics on the process results are highlighted.

Jayakumar, P.; Babu, N. R.; Radhakrishnan, V.

1998-04-01

178

Machining human dentin by abrasive water jet drilling.  

PubMed

The aim of this experimental in-vitro study was to investigate the machining of human dentin using an abrasive water jet and to evaluate the influence of different abrasives and water pressures on the removal rate. Seventy-two human teeth had been collected after extraction and randomly divided into six homogeneous groups (n=12). The teeth were processed in the area of root dentin with an industrial water jet device. Different abrasives (saccharose, sorbitol, xylitol) and water pressures (15 or 25 MPa) were used in each group. Dimensions of dentin removal were analysed using a stripe projection microscope and both drilling depth as well as volume of abrasion were recorded. Morphological analyses of the dentin cavities were performed using scanning electron microscopy (SEM). Both drilling depth and volume of abrasion were significantly influenced by the abrasive and the water pressure. Depending on these parameters, the drilling depth averaged between 142 and 378 ?m; the volume of abrasion averaged between 0.07 and 0.15 mm3. Microscopic images revealed that all cavities are spherical and with clearly defined margins. Slight differences between the abrasives were found with respect to the microroughness of the surface of the cavities. The results indicate that abrasive water jet machining is a promising technique for processing human dentin. PMID:24642975

Kohorst, Philipp; Tegtmeyer, Sven; Biskup, Christian; Bach, Friedrich-Wilhelm; Stiesch, Meike

2014-01-01

179

Mars Pathfinder Wheel Abrasion Experiment Ground Test  

NASA Technical Reports Server (NTRS)

The National Aeronautics and Space Administration (NASA) sent a mission to the martian surface, called Mars Pathfinder. The mission payload consisted of a lander and a rover. The primary purpose of the mission was demonstrating a novel entry, descent, and landing method that included a heat shield, a parachute, rockets, and a cocoon of giant air bags. Once on the surface, the spacecraft returned temperature measurements near the Martian surface, atmosphere pressure, wind speed measurements, and images from the lander and rover. The rover obtained 16 elemental measurements of rocks and soils, performed soil-mechanics, atmospheric sedimentation measurements, and soil abrasiveness measurements.

Keith, Theo G., Jr.; Siebert, Mark W.

1998-01-01

180

Evaluation of Particles Released from Single-wall Carbon Nanotube/Polymer Composites with or Without Thermal Aging by an Accelerated Abrasion Test.  

PubMed

To provide data required for assessing the environmental health and safety risks of nanocomposites, abrasion-induced particle release from single-wall carbon nanotube (SWCNT)/polymer composites with or without thermal aging were evaluated by a shot blast system. First, overall composite weight loss (i.e., overall particle release) as a result of shot blasting was measured. Incorporating 5 wt% SWCNTs in polystyrene (PS) matrix was observed to reduce overall particle release by approximately 30% compared with pure PS. Heat treatment of the 5 wt% SWCNT/PS composites at 100°C for 10 days induced very slight change in overall particle release due to shot blasting. However, heat treatment at 350°C for 1 hr greatly deteriorated the abrasion resistance of the composites, enhancing overall particle release. Second, to verify the existence and form of SWCNTs released from the composites, released particles were observed by electron microscopy. Micron-sized particles with protruding SWCNTs and submicron-sized SWCNT clusters were observed in the particles released from the composites. Heat treatment of the composites at 350°C for 1 hr enhanced SWCNT release, which mainly formed clusters or rope-like bundles. PMID:24628695

Jiang, Lin; Kondo, Akira; Shigeta, Masahiro; Endoh, Shigehisa; Uejima, Mitsugu; Ogura, Isamu; Naito, Makio

2014-10-01

181

Method for removing surface-damaged layers from nickel alloys  

NASA Technical Reports Server (NTRS)

Electrical discharge machining /EDM/ damaged layer can be effectively removed from Rene 41, Inconel 625, Inconel 718, and Monel K-500 by abrasive-grit blasting or electropolishing /at room temperature/ at a current density of 5A/inches squared in a water solution of phosphoric and sulfuric acids.

Fawley, R. W.

1968-01-01

182

Laser Surface Preparation and Bonding of Aerospace Structural Composites  

NASA Technical Reports Server (NTRS)

A Nd:YAG laser was used to etch patterns conducive to adhesive bonding onto CFRP surfaces. These were compared to typical pre-bonding surface treatments including grit blasting, manual abrasion, and peel ply. Laser treated composites were then subjected to optical microscopy, contact angle measurements, and post-bonding mechanical testing.

Belcher, Marcus A.; Wohl, Christopher J.; Connell, John W.

2009-01-01

183

Comparison of exposed dentinal surfaces resulting from abrasion and erosion  

Microsoft Academic Search

The aim of this study was to compare the shape of exposed dentinal surfaces caused by abrasion and erosion with a view to developing a diagnostic clinical test. The study material consisted of 80 natural teeth and 129 dental models obtained from Australian Aborigines known to display considerable dental abrasion due to their diet, and dental models of 37 Caucasians

Emma Jane Bell; John Kaidonis; Grant Townsend; Lindsay Richards

1998-01-01

184

Efficient automatic polishing process with a new compliant abrasive tool  

Microsoft Academic Search

In this paper, an efficient polishing process is proposed for precision polishing tasks using a new compliant abrasive tool. The polishing process is conducted by a force-controllable five-axes robot. The polishing process comprises many steps using different abrasive grain sizes. For each process step, an optimal set of polishing parameters that can efficiently reduce surface roughness is determined by the

M. J. Tsai; J. F. Huang

2006-01-01

185

Results of thoracoscopic pleural abrasion for primary spontaneous pneumothorax  

Microsoft Academic Search

Background: Several video-assisted techniques have been used to treat primary spontaneous pneumothorax (PSP). The aim of this study was to evaluate the results of thoracoscopic pleural abrasion for PSP. Methods: From 1991 to 2003, 185 consecutive patients, 143 male and 42 female, aged 15 to 60 years (average 31.6) underwent thoracoscopic pleural abrasion for PSP. The indications for surgery were

D. Gossot; D. Galetta; J. B. Stern; D. Debrosse; R. Caliandro; P. Girard; D. Grunenwald

2004-01-01

186

Development of the dry sand\\/rubber wheel abrasion test  

Microsoft Academic Search

A rubber wheel abrasion tester with some advantages over the design described in ASTM G65 has been designed and characterised. In the new design the specimen was held horizontally. It was therefore possible to determine the actual mass flow rate of abrasive abrading the specimen and consequently the number of particles in the contact zone and the load carried by

A. N. J. Stevenson; I. M. Hutchings

1996-01-01

187

Improving Electrical Discharge Machined Surfaces Using Magnetic Abrasive Finishing  

Microsoft Academic Search

A recast layer is invariably present on surfaces produced by electrical discharge machining (EDM). For some metals with high hardness, the recast layer may contain micro-cracks. This damaged layer can affect the service life of the parts produced by this method. This investigation demonstrates that magnetic abrasive finishing (MAF) process using unbonded magnetic abrasives (UMA), can improve the quality of

Biing-Hwa Yan; Geeng-Wei Chang; Jung-Hsien Chang; Rong-Tzong Hsu

2004-01-01

188

AN EXPERIMENTAL ANALYSIS OF MAGNETIC ABRASIVES FINISHING OF PLANE SURFACES  

Microsoft Academic Search

Magnetic abrasive finishing (MAF) uses magnetic force of very low magnitude applied on ferromagnetic abrasive particles to obtain very high level surface finish. The process has been investigated extensively in the finishing of cylindrical surfaces. This paper reports an experimental work on the analysis of surface roughness and material removal using response surface method in the MAF of plane surfaces.

Berhanu Girma; Suhas S. Joshi; M. V. G. S. Raghuram; R. Balasubramaniam

2006-01-01

189

Microwave sintering of sol-gel derived abrasive grain  

DOEpatents

A method is provided for making microwave-sintered, free flowing alpha alumina-based ceramic abrasive grain, under conditions effective to couple microwaves with calcined alpha alumina-based abrasive gain precursor and sinter it at a temperature of at least about 1150.degree. C.

Plovnick, Ross (St. Louis Park, MN); Celikkaya, Ahmet (Woodbury, MN); Blake, Rodger D. (Tuscon, AZ)

1997-01-01

190

Microscale abrasive wear of coated surfaces-prediction models  

Microsoft Academic Search

Micro-scale abrasive wear testing is widely used to characterise thinly coated surfaces. Beyond the several advantages of this technique, the possibility of finding the specific wear rates both for the substrate and for the coating with only one set of tests on coated specimens is certainly an important reason for the rapid spread of the micro-scale abrasive technique. It has

A. Ramalho

2005-01-01

191

The model of abrasive wear of concrete in hydraulic structures  

Microsoft Academic Search

Abrasion wear of concrete in hydraulic construction is caused by movement of rubble carried by water. Difficulties in methodology of modelling this process in a laboratory scale constitute an obstacle to the rational assessment of influence of material and environmental conditions on durability of objects exposed to these actions. This paper presents a new concept of testing the abrasion of

E. Horszczaruk

2004-01-01

192

Advancement of Abrasive Flow Machining Using an Anodic Solution  

Microsoft Academic Search

Results of the research on the electrochemically assisted abrasive flow machining (ECAFM) have been presented in this paper. The experimental evaluation of several solid electrolytes with various bonds has been carried out (the polypropylene glycol PPG with the NaI salt share and ethylene glycol PEG with KSCN salt share have been subjected to the tests). The abrasive properties of the

Lucjan Dabrowski; Mieczyslaw Marciniak; W ?adyslaw Wieczorek; Anna Zygmunt

193

Fluid flow analysis of magnetorheological abrasive flow finishing (MRAFF) process  

Microsoft Academic Search

A new precision finishing process called magnetorheological abrasive flow finishing (MRAFF), which is basically a combination of abrasive flow machining (AFM) and magnetorheological finishing (MRF), has been developed for nano-finishing of parts even with complicated geometry for a wide range of industrial applications. This paper deals with the theoretical investigations into the mechanism of MRAFF process to study the effects

Manas Das; V. K. Jain; P. S. Ghoshdastidar

2008-01-01

194

Modelling the abrasive flow machining process on advanced ceramic materials  

Microsoft Academic Search

Abrasive flow machining (AFM) is a unique machining method used to achieve high surface quality on inner, difficult-to-access and on outside contours. Using AFM, it is possible to realise predefined edge rounding on any brittle or hard material. AFM is easy to integrate in an automated manufacturing environment. The abrasive medium applied during AFM is a fluid consisting of a

Eckart Uhlmann; Vanja Mihotovic; Andre Coenen

2009-01-01

195

Experimental investigations into rotating workpiece abrasive flow finishing  

Microsoft Academic Search

Abrasive flow finishing (AFF) is used to deburr, polish or radius surfaces and edges by flowing a semisolid abrasive medium over the intended surface to be finished. Such finishing operations play a crucial role in manufacturing process of machine parts. The cost escalates sharply when the requirement is to achieve surface roughness values near nano levels. The need for finishing

Mamilla Ravi Sankar; V. K. Jain; J. Ramkumar

2009-01-01

196

Coated Abrasive Machining of Titanium Alloys with Inorganic Phosphate Solutions  

Microsoft Academic Search

Titanium alloys designed for aerospace applications are extremely difficult to grind. Although the high strength of these alloys is a major cause of poor grindability, chemical adhesion of the titanium to the abrasive grain is also a factor contributing to poor abrasive performance. These difficulties can be alleviated by proper choice of grinding fluid. This paper describes work in which

I. S. Hong; E. J. Duwell; W. J. McDonald; C. E. Mereness

1971-01-01

197

Performance of two strains of laying hens fed ground and whole barley with and without access to insoluble grit.  

PubMed

The live performance from 19 to 43 wk of age of two strains of commercial White Leghorn hens fed two levels of whole barley (0 or 60%) and insoluble grit (0 or 4 g/bird per wk) was compared. The 0 and 60% whole barley diets differed only in feed form and were formulated to the same nutrient specifications. No dilution of nutrients or ingredients occurred. The 0% whole barley diet was fed in mash form. The 60% whole barley diet was fed as whole grain and mash concentrate blended into a complete diet and fed in the same feed trough. Feeding whole barley reduced egg production, feed efficiency, and egg specific gravity and increased feed intake, egg weight, and body weight gain. Access to insoluble grit had no effect on any of the production variables measured. The two strains of hens responded similarly to whole barley but differed in feed intake, feed efficiency, egg weight, egg specific gravity, and body weight gain. Feeding whole barley combined with a mash concentrate depressed hen performance compared to birds fed a similar diet in mash form. Strain of hen and access to insoluble grit did not alter the response to feeding whole barley. PMID:12580257

Bennett, C D; Classen, H L

2003-01-01

198

Micro Fluidic Channel Machining on Fused Silica Glass Using Powder Blasting  

PubMed Central

In this study, micro fluid channels are machined on fused silica glass via powder blasting, a mechanical etching process, and the machining characteristics of the channels are experimentally evaluated. In the process, material removal is performed by the collision of micro abrasives injected by highly compressed air on to the target surface. This approach can be characterized as an integration of brittle mode machining based on micro crack propagation. Fused silica glass, a high purity synthetic amorphous silicon dioxide, is selected as a workpiece material. It has a very low thermal expansion coefficient and excellent optical qualities and exceptional transmittance over a wide spectral range, especially in the ultraviolet range. The powder blasting process parameters affecting the machined results are injection pressure, abrasive particle size and density, stand-off distance, number of nozzle scanning, and shape/size of the required patterns. In this study, the influence of the number of nozzle scanning, abrasive particle size, and pattern size on the formation of micro channels is investigated. Machined shapes and surface roughness are measured using a 3-dimensional vision profiler and the results are discussed.

Jang, Ho-Su; Cho, Myeong-Woo; Park, Dong-Sam

2008-01-01

199

Experimental Rock-on-Rock Abrasive Wear Under Aqueous Conditions: its Role in Subglacial Abrasion  

NASA Astrophysics Data System (ADS)

We have determined experimentally the rate of abrasive wear of rock on rock for a range of rock types as a function of normal stress and shear displacement. Unlike abrasive wear in fault zones, where wear products accumulate as a thickening gouge zone, in our experiments wear particles were removed by flowing water. The experiments are thus directly pertinent to one of the most important processes in subglacial erosion, and to some extent in river incision. Wear was produced between rotating discs machined from rock samples and measured from the progressive approach of the disc axes towards each other under various levels of normal load. Shear displacements of several km were produced. Optical and scanning electron microscopy were used to study the worn rock surfaces, and particle size distributions in wear products were characterized using a laser particle size analyzer. Rock types studied were sandstones of various porosities and cement characteristics, schists and a granite. In all cases abrasion rate decreased logarithmically with displacement by up to 2 orders of magnitude until a steady state was approached, but only after at least 1 km displacement. The more porous, less-well cemented rocks wore fastest. Amount of abrasion could be characterized quantitatively using an exponentially decaying plus a steady-state term. Wear rate increased non-linearly with normal contact stress, apparently to an asymptote defined by the unconfined compressive strength. Microstructural study showed that the well-cemented and/or lowest porosity rocks wore by progressive abrasion of grains without plucking, whereas whole grains were plucked out of weakly-cemented and/or more porous rocks. This difference in behavior was reflected in wear-product particle size distributions. Where whole-grain plucking was possible, wear products were dominated by particles of the original grain size rather than finer rock flour. Comparison of our results to glacier basal abrasive wear estimated from suspended sediment load (Findeln Glacier, Switzerland) showed the steady-state experimental data seriously to underestimate the natural wear rate. This suggests continuous resetting of the subglacial surface occurs, so that wear is continuously in the 'running-in' stage.

Rutter, E. H.; Lee, A. G.

2003-12-01

200

SPECIFIC ENERGY AND SCRATCH HARDNESS OF GAMMA TITANIUM ALUMINIDES SUBJECTED TO SINGLE-GRIT PENDULUM SCRATCHING  

SciTech Connect

Two gamma titanium aluminides TiAls (Daido TiAl HIP and HOWMET TiAl) with fully lamellar structure but with different colony sizes were studied using a single-grit pendulum (rotational) scratch tester. The maximum depth of groove was ~ 0.07 mm and the scratch velocity used was ~ 1,000 mm/s. Normal and tangential forces were monitored during each scratch. The material removal mechanisms were examined using a scanning electronic microscope (SEM), and also measured by using a laser profilometer. Extensive thermal softening was observed. Sizable fractures were revealed in the transverse direction; however the role of these fractures in the chip formation depends on the microstructure of materials and the size of groove. The tribological properties were characterized by instantaneous specific energy and scratch hardness as related to the depth of groove. The overall response of materials can be effectively characterized by a two-parameter model, namely, HEM model and PSR model, even though the underlining material removal might be subjected to the different mechanisms. The TiAl with the larger colony or grain size exhibits a strong resistance to material loss or material removal (higher depth-independent specific energy) while exhibiting lower scratch hardness. The obtained depth-independent specific energy and scratch hardness can be used to screen the candidate materials depending on whether the application is sliding or impact dominant.

Wang, Hong [ORNL; Lin, Hua-Tay [ORNL; Wereszczak, Andrew A [ORNL

2006-01-01

201

Silicon slicing by fixed abrasive slicing technique  

NASA Technical Reports Server (NTRS)

One of the major cost factors in silicon ingot technology adaptation for terrestrial photovoltaic application is in slicing boules into wafers. The most developed industrial practice is the Internal Diameter (ID) slicing. This method utilizes diamond cutting. The diamond stands up for long periods, hence, the cost of expendable materials is low. However, the ID technology as practiced today has poor material utilization. The Multiblade Slurry (MBS) method has low equipment and labor costs but its expendable material costs are high. Recently Multiwire Slurry (MWS) technology has shown very good material utilization, but its expendable material costs are even higher than MBS. The multiwire Fixed Abrasive Slicing Technique (FAST) still in advanced development stage, combines the low expendable material costs of ID method, the low labor and equipment costs of MBS and high material utilization of MWS.

Schmid, F.; Khattak, C. P.

1982-01-01

202

CRCHD E-blast  

Cancer.gov

CRCHD E-blast CRCHD Web Site Updates The Center to Reduce Cancer Health Disparities (CRCHD) has recently updated some of its web pages! Please take the time to browse through these updates. Site updates include: The CRCHD 2011 Annual Report, a newly

203

CRCHD E-blast  

Cancer.gov

CRCHD E-blast CRCHD Web Site Updates The Center to Reduce Cancer Health Disparities (CRCHD) has recently updated some of its Web pages! Please take the time to browse through these updates. Site updates include: 2013 Annual Report to the Nation on

204

Fatigue behavior of Ti6Al4V and 316 LVM blasted with ceramic particles of interest for medical devices.  

PubMed

Grit blasting is used as a cost-effective method to increase the surface roughness of metallic biomaterials, as Ti6Al4V and 316 LVM, to enhance the osteointegration, fixation and stability of implants. Samples of these two alloys were blasted by using alumina and zirconia particles, yielding rough (up to Ra~8?m) and nearly smooth (up to Ra~1?m) surfaces, respectively. In this work, we investigate the sub-surface induced microstructural effects and its correlation with the mechanical properties, with special emphasis in the fatigue behavior. Blasting with zirconia particles increases the fatigue resistance whereas the opposite effect is observed using alumina ones. As in a conventional shot penning process, the use of rounded zirconia particles for blasting led to the development of residual compressive stresses at the surface layer, without zones of stress concentrators. Alumina particles are harder and have an angular shape, which confers a higher capability to abrade the surface, but also a high rate of breaking down on impact. The higher roughness and the presence of a high amount of embedded alumina particles make the blasted alloy prone to crack nucleation. Interestingly, the beneficial or detrimental role of blasting is more intense for the Ti6Al4V alloy than for the 316 steel. It is proposed that this behavior is related to their different strain hardening exponents and the higher mass fraction of particles contaminating the surface. The low value of this exponent for the Ti6Al4V alloy justifies the expected low sub-surface hardening during the severe plastic deformation, enhancing its capability to soft during cyclic loading. PMID:24216310

Barriuso, S; Chao, J; Jiménez, J A; García, S; González-Carrasco, J L

2014-02-01

205

BLAST: THE REDSHIFT SURVEY  

SciTech Connect

The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) has recently surveyed approx =8.7 deg{sup 2} centered on Great Observatories Origins Deep Survey-South at 250, 350, and 500 mum. In Dye et al., we presented the catalog of sources detected at 5sigma in at least one band in this field and the probable counterparts to these sources in other wavebands. In this paper, we present the results of a redshift survey in which we succeeded in measuring redshifts for 82 of these counterparts. The spectra show that the BLAST counterparts are mostly star-forming galaxies but not extreme ones when compared to those found in the Sloan Digital Sky Survey. Roughly one quarter of the BLAST counterparts contain an active nucleus. We have used the spectroscopic redshifts to carry out a test of the ability of photometric redshift methods to estimate the redshifts of dusty galaxies, showing that the standard methods work well even when a galaxy contains a large amount of dust. We have also investigated the cases where there are two possible counterparts to the BLAST source, finding that in at least half of these there is evidence that the two galaxies are physically associated, either because they are interacting or because they are in the same large-scale structure. Finally, we have made the first direct measurements of the luminosity function in the three BLAST bands. We find strong evolution out to z = 1, in the sense that there is a large increase in the space density of the most luminous galaxies. We have also investigated the evolution of the dust-mass function, finding similar strong evolution in the space density of the galaxies with the largest dust masses, showing that the luminosity evolution seen in many wavebands is associated with an increase in the reservoir of interstellar matter in galaxies.

Eales, Stephen; Dye, Simon; Mauskopf, Philip; Moncelsi, Lorenzo; Pascale, Enzo; Raymond, Gwenifer [Cardiff University, School of Physics and Astronomy, Queens Buildings, The Parade, Cardiff, CF24 3AA (United Kingdom); Chapin, Edward L.; Halpern, Mark; Marsden, Gaelen; Scott, Douglas [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Devlin, Mark J.; Rex, Marie; Semisch, Christopher; Truch, Matthew D. P. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia PA, 19104 (United States); Hughes, David H. [Instituto Nacional de AstrofIsica Optica y Electronica (INAOE), Aptdo. Postal 51 y 72000 Puebla (Mexico); Netterfield, Calvin B.; Viero, Marco P. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street Toronto, ON M5S 3H4 (Canada); Patanchon, Guillaume [Universite Paris Diderot, Laboratoire APC, 10, rue Alice Domon et Leonie Duquet 75205 Paris (France); Siana, Brian [California Institute of Technology, MS 105-24, Pasadena, CA 91125 (United States)

2009-12-20

206

Method for forming an abrasive surface on a tool  

DOEpatents

A method for fabricating a tool used in cutting, grinding and machining operations, is provided. The method is used to deposit a mixture comprising an abrasive material and a bonding material on a tool surface. The materials are propelled toward the receiving surface of the tool substrate using a thermal spray process. The thermal spray process melts the bonding material portion of the mixture, but not the abrasive material. Upon impacting the tool surface, the mixture or composition solidifies to form a hard abrasive tool coating.

Seals, Roland D. (Oak Ridge, TN); White, Rickey L. (Harriman, TN); Swindeman, Catherine J. (Knoxville, TN); Kahl, W. Keith (Knoxville, TN)

1999-01-01

207

Lateral Crack in Abrasive Wear of Brittle Materials  

NASA Astrophysics Data System (ADS)

An analytical model for lateral cracks occurring in abrasive wear of brittle materials was developed. The stress field around the lateral crack and the stress intensity factor at the crack tip were analytically modeled. The abrasive wear by abrasive particles was experimentally studied by sliding indentation. In soda-lime glass, it was observed that chipping by the lateral crack occurred and produced the greatest material removal when the normal load applied by the sliding indenter was about 1.5-2.0N. Prediction of length of the lateral crack from the model was compared with the experimentally measured length in the soda-lime glass.

Ahn, Yoomin; Cho, Nahm-Gyoo; Lee, Seoung-Hwan; Lee, Dohyung

208

Effects of grit roughness and pitch oscillations on the NACA 4415 airfoil  

SciTech Connect

A NACA 4415 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory 3 x 5 subsonic wind tunnel under steady state and unsteady conditions. The test defined baseline conditions for steady state angles of attack from {minus}10{degree} to +40{degree} and examined unsteady behavior by oscillating the model about its pitch axis for three mean angles, three frequencies, and two amplitudes. For all cases, Reynolds numbers of 0.75, 1, 1.25, and 1.5 million were used. In addition, these were repeated after the application of leading edge grit roughness (LEGR) to determine contamination effects on the airfoil performance. Steady state results of the NACA 4415 testing at Reynolds number of 1.25 million showed a baseline maximum lift coefficient of 1.30 at 12.3{degree} angle of attack. The application of LEGR reduced the maximum lift coefficient by 20% and increased the 0.0090 minimum drag coefficient value by 62%. The zero lift pitching moment of {minus}0.0967 showed a 13% reduction in magnitude to {minus}0.0842 with LEGR applied. Data were also obtained for two pitch oscillation amplitudes: {+-}5.5{degree} and {+-}10{degree}. The larger amplitude consistently gave a higher maximum lift coefficient than the smaller amplitude, and both unsteady maximum lift coefficients were greater than the steady state values. Stall is delayed on the airfoil while the angle of attack is increasing, thereby causing an increase in maximum lift coefficient. A hysteresis behavior was exhibited for all the unsteady test cases. The hysteresis loops were larger for the higher reduced frequencies and for the larger amplitude oscillations. As in the steady case, the effect of LEGR in the unsteady case was to reduce the lift coefficient at high angles of attack. In addition, with LEGR, the hysteresis behavior persisted into lower angles of attack than for the clean case.

Hoffmann, M.J.; Reuss Ramsay, R.; Gregorek, G.M. [Ohio State Univ., Columbus, OH (United States)

1996-07-01

209

Effects of grit roughness and pitch oscillations on the S810 airfoil  

SciTech Connect

An S810 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory 3 x 5 subsonic wind tunnel under steady state and unsteady conditions. The test defined baseline conditions for steady state angles of attack from -20{degrees} to +40{degrees} and examined unsteady behavior by oscillating the model about its pitch axis for three mean angles, three frequencies, and two amplitudes. For all cases, Reynolds numbers of 0.75, 1, 1.25, and 1.5 million were used. In addition, the above conditions were repeated after the application of leading edge grit roughness (LEGR) to determine contamination effects on the airfoil performance. Baseline steady state results of the S810 testing showed a maximum lift coefficient of 1.15 at 15.2{degrees}angle of attack. The application of LEGR reduced the maximum lift coefficient by 12% and increased the 0.0085 minimum drag coefficient value by 88%. The zero lift pitching moment of -0.0286 showed a 16% reduction in magnitude to -0.0241 with LEGR applied. Data were also obtained for two pitch oscillation amplitudes: {plus_minus}5.5{degrees} and {plus_minus}10{degrees}. The larger amplitude consistently gave a higher maximum lift coefficient than the smaller amplitude and both sets of unsteady maximum lift coefficients were greater than the steady state values. Stall was delayed on the airfoil while the angle of attack was increasing, thereby causing an increase in maximum lift coefficient. A hysteresis behavior was exhibited for all the unsteady test cases. The hysteresis loops were larger for the higher reduced frequencies and for the larger amplitude oscillations. In addition to the hysteresis behavior, an unusual feature of these data were a sudden increase in the lift coefficient where the onset of stall was expected. As in the steady case, the effect of LEGR in the unsteady case was to reduce the lift coefficient at high angles of attack.

Ramsay, R.R.; Hoffman, M.J.; Gregorek, G.M. [Ohio State Univ., Columbus, OH (United States)

1996-01-01

210

Study of an internal magnetic abrasive finishing using a pole rotation system  

Microsoft Academic Search

An internal magnetic abrasive finishing process using a pole rotation system was proposed to produce highly finished inner surfaces of workpieces used in critical applications. Previous research found that the process incorporating one of the characteristic behaviors of the abrasive, the jumbling of the abrasive, results in aggressive contact of the abrasive against the inner surface, disturbing the smooth surface

Hitomi Yamaguchi; Takeo Shinmura

2000-01-01

211

Prediction System of Magnetic Abrasive Finishing (MAF) on the Internal Surface of a Cylindrical Tube  

Microsoft Academic Search

This study mainly used magnetic abrasive finishing (MAF) to explore a stainless steel SUS304 cylindrical tube related to the processing characteristic and the prediction system. The self-made adjustable electricity polishing mechanism was assembled on a magnetic abrasive machine. The cylindrical stainless steel tube was filled with magnetic abrasive, which consisted of sintered iron and aluminum oxide powder. Magnetic abrasive in

Ching-Lien Hung; Wei-Liang Ku; Lieh-Dai Yang

2010-01-01

212

Installation for Precise Feed Micro Abrasive and Experiments Based on Auger Mechanism  

Microsoft Academic Search

In order to resolve the difficulty of micro abrasive feed continuously and precisely in micro abrasive water jet machining, an installation for precise feed micro abrasive was designed based on principle of material conveying by auger mechanism. The auger is driven by DC motor reducer. The abrasive flow rate is controlled precisely by regulating the revolve speed of DC motor.

Lei Yuyong; Tang Puhua; Jiang Daijun; Liu Kefu; Dai Liangbo

2010-01-01

213

Preliminary Investigation of the Effect of Surface Treatment on the Strength of a Titanium Carbide - 30 Percent Nickel Base Cermet  

NASA Technical Reports Server (NTRS)

Specimens of a nickel-bonded titanium carbide cermet were given the following surface treatments: (1) grinding, (2) lapping, (3) blast cleaning, (4) acid roughening, (5) oxidizing, and (6) oxidizing and refinishing. Room-temperature modulus-of-rupture and impact strength varied with the different surface treatments. Considerable strength losses resulted from the following treatments: (1) oxidation at 1600 F for 100 hours, (2) acid roughening, and (3) severe grinding with 60-grit silicon carbide abrasive. The strength loss after oxidation was partially recovered by grit blasting or diamond grinding.

Robins, Leonard; Grala, Edward M

1957-01-01

214

7 CFR 3201.66 - Cuts, burns, and abrasions ointments.  

Code of Federal Regulations, 2012 CFR

...Definition. Products designed to aid in the healing and sanitizing of scratches, cuts, bruises, abrasions, sun damaged skin, tattoos, rashes and other skin conditions. (b) Minimum biobased content. The Federal preferred procurement product...

2012-01-01

215

29 CFR 1926.303 - Abrasive wheels and tools.  

...SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Tools-Hand and Power § 1926.303 Abrasive wheels and tools. (a) Power. All grinding machines shall be supplied with...

2014-07-01

216

Sliding-Gate Valve for Use with Abrasive Materials.  

National Technical Information Service (NTIS)

The invention is a flow and pressure-sealing valve for use with abrasive solids. The valve embodies special features which provide for long, reliable operating lifetimes in solids-handling service. The valve includes upper and lower transversely slidable ...

W. J. Ayers, C. R. Carter, R. A. Griffith, R. B. Loomis, J. E. Notestein

1982-01-01

217

7 CFR 3201.66 - Cuts, burns, and abrasions ointments.  

...ointments. (a) Definition. Products designed to aid in the healing and sanitizing of scratches, cuts, bruises, abrasions, sun damaged skin, tattoos, rashes and other skin conditions. (b) Minimum biobased content. The Federal preferred...

2014-01-01

218

7 CFR 3201.66 - Cuts, burns, and abrasions ointments.  

Code of Federal Regulations, 2013 CFR

...ointments. (a) Definition. Products designed to aid in the healing and sanitizing of scratches, cuts, bruises, abrasions, sun damaged skin, tattoos, rashes and other skin conditions. (b) Minimum biobased content. The Federal preferred...

2013-01-01

219

Influence of coating microstructure on the abrasive wear resistance of WC\\/Co cermet coatings  

Microsoft Academic Search

Thermally sprayed WC\\/Co cermet coatings are widely used for their resistance to abrasive wear. In this work the influence of the abrasive grain size on the abrasive wear resistance was investigated for WC\\/Co coatings sprayed with several processes: APS, high-velocity oxy-fuel (HVOF) and VPS. Results show that the larger the abrasive particle size, the lower the abrasion resistance of the

H. Liao; B. Normand; C. Coddet

2000-01-01

220

Magnetic abrasive finishing of hardened AISI 52100 steel  

Microsoft Academic Search

Surface finish has a vital influence on functional properties such as wear resistance and power loss due to friction on most\\u000a of the engineering components. Magnetic abrasive finishing (MAF) is one of the advanced finishing process in which a surface\\u000a is finished by removing the material in the form of microchips by abrasive particles in the presence of magnetic field

Rahul S. Mulik; Pulak M. Pandey

2011-01-01

221

Modeling of Polishing Mechanism in Magnetic Abrasive Polishing  

Microsoft Academic Search

Magnetic Abrasive Polishing (MAP) is a super-finishing process primarily used for polishing of non- magnetic and hard materials like, ceramics and stainless steel. This paper deals with the detailed parametric study in polishing of stainless steel work surface. Statistically designed experiments based on Taguchi methods show that size-ratio, tool-work surface clearance, polishing speed, magnetic abrasive diameter and polishing time have

M. G. V. S. Raghuram; Suhas S. Joshi

222

Micro-contact based modelling of abrasive wear  

Microsoft Academic Search

A model that describes the abrasive wear between a hard and rough surface and a softer and smooth surface is developed. The contact between these two solids is modelled based on micro-contacts [M.A. Masen, M.B. de Rooij, Abrasive wear between rough surfaces in deep drawing, in: Proceedings of the 6th Austrib Tribology Conference, Perth, Australia, 2002, pp. 601–608], instead of

M. A. Masen; M. B. de Rooij; D. J. Schipper

2005-01-01

223

Movement patterns of ellipsoidal particle in abrasive flow machining  

Microsoft Academic Search

Abrasive particle movement pattern is an important factor in estimating the wear rate of materials, especially, as it is closely related to the burring, buffing and polishing efficiency of the abrasive flow machining (AFM) process. There are generally two kinds of particle movement patterns in the AFM process, i.e. sliding–rubbing and rolling. In mechanism, AFM particle–workpiece interaction is taking place

Liang Fang; Jia Zhao; Bo Li; Kun Sun

2009-01-01

224

Effects of fluvial abrasion on shapes of quartz sand grains  

SciTech Connect

The effects of abrasion on the shapes of medium and fine quartz sand grains that are transported through a 300-mi (500-km) stretch of the Mississippi River were determined by Fourier grain-shape measurement and scanning electron microscopy. The results indicate that the abrasion of medium and fine quartz sand grains in the low-gradient stream does not significantly affect their source-inherited shapes.

Peterson, M.; Mazzullo, J.

1987-09-01

225

The abrasion of acrylic resin by cleaning pastes.  

PubMed

The physical removal of plaque from dentures by brushing is important in the maintenance of oral health. However, there is a danger that brushing will abrade acrylic resin. A machine using a rotary brushing action was therefore utilized for laboratory tests of possible cleaning pastes, employing a toothbrush with good access and adaptability to denture surfaces. Crest toothpaste produced the most abrasion on acrylic resin, Dentu-Creme the least. An experimental paste produced an appreciably lower abrasion rate. Self-cured specimens wore more than heat-cured ones. The rate of abrasion decreased as the temperature was raised. Brushing with water alone, or with a 10% solution of soap, did not produce detectable wear. The wear produced by proprietary cleaners when hand brushing the lingual flanges of dentures and flat blanks of heat-cured acrylic was also measured. Boots denture cleaning paste produced the greatest abrasion, Dentu-Creme the least. The wear measured by reference to a glass plane was at least twice that recorded by the decrease in depth of a groove. The machine did not quantitatively produce the same abrasion as hand brushing, nor did it qualitatively rank the pastes in the same order of abrasiveness. The clinical relevance of these results is discussed. PMID:6573464

Heath, J R; Davenport, J C; Jones, P A

1983-03-01

226

Method of protecting surfaces from abrasion and abrasion resistant articles of manufacture  

DOEpatents

Surfaces of fabricated structures are protected from damage by impacting particulates by a coating of hard material formed as a mass of thin flexible filaments having root ends secured to the surface and free portions which can flex and overlap to form a resilient cushioning mat which resembles hair or fur. The filamentary coating covers the underlying surface with hard abrasion resistance material while also being compliant and capable of local accommodation to particle impacts. The coating can also function as thermal and/or acoustical insulation and has a friction reducing effect. 11 figs.

Hirschfeld, T.B.

1988-06-09

227

Performance of blasting caps  

NASA Technical Reports Server (NTRS)

Common blasting caps are made from an aluminum shell in the form of a tube which is closed at both ends. One end, which is called the output end, terminates in a principal side or face, and contains a detonating agent which communicates with a means for igniting the detonating agent. The improvement of the present invention is a flat, steel foil bonded to the face in a position which is aligned perpendicularly to the longitudinal axis of the tube.

Bement, Laurence J. (inventor); Schimmel, Morry L. (inventor); Perry, Ronnie B. (inventor)

1993-01-01

228

Dynamical simulation of an abrasive wear process  

NASA Astrophysics Data System (ADS)

A dynamic computer model was developed to simulate wear behavior of materials on micro-scales. In this model, a material system is discretized and mapped onto a lattice or grid. Each lattice site represents a small volume of the material. During a wear process, a lattice site may move under the influence of external force and the interaction between the site and its adjacent sites. The site-site interaction is a function of mechanical properties of the material such as the elastic modulus, yield strength, work hardening and the fracture strain. Newton's law of motion is used to determine the movement of lattice sites during a wear process. The strain between a pair of sites is recoverable if it is within the elastic deformation range; otherwise plastic deformation takes place. A bond between two adjacent sites is broken when its strain exceeds a critical value. A site or a cluster of sites is worn away if all bonds connecting the site or the cluster to its nearest neighbors are broken. The model well describes the strain distribution in a contact region, in consistence with a finite element analysis. This model was applied to several metallic materials abraded under the ASTM G65 abrasion condition, and the results were compared to experimental observations. Good agreement between the modeling and the experiment was found.

Elalem, Khaled; Li, D. Y.

1999-05-01

229

Computed tomography to quantify tooth abrasion  

NASA Astrophysics Data System (ADS)

Cone-beam computed tomography, also termed digital volume tomography, has become a standard technique in dentistry, allowing for fast 3D jaw imaging including denture at moderate spatial resolution. More detailed X-ray images of restricted volumes for post-mortem studies in dental anthropology are obtained by means of micro computed tomography. The present study evaluates the impact of the pipe smoking wear on teeth morphology comparing the abraded tooth with its contra-lateral counterpart. A set of 60 teeth, loose or anchored in the jaw, from 12 dentitions have been analyzed. After the two contra-lateral teeth were scanned, one dataset has been mirrored before the two datasets were registered using affine and rigid registration algorithms. Rigid registration provides three translational and three rotational parameters to maximize the overlap of two rigid bodies. For the affine registration, three scaling factors are incorporated. Within the present investigation, affine and rigid registrations yield comparable values. The restriction to the six parameters of the rigid registration is not a limitation. The differences in size and shape between the tooth and its contra-lateral counterpart generally exhibit only a few percent in the non-abraded volume, validating that the contralateral tooth is a reasonable approximation to quantify, for example, the volume loss as the result of long-term clay pipe smoking. Therefore, this approach allows quantifying the impact of the pipe abrasion on the internal tooth morphology including root canal, dentin, and enamel volumes.

Kofmehl, Lukas; Schulz, Georg; Deyhle, Hans; Filippi, Andreas; Hotz, Gerhard; Berndt-Dagassan, Dorothea; Kramis, Simon; Beckmann, Felix; Müller, Bert

2010-09-01

230

Effect of carbide degradation in a Ni-based hardfacing under abrasive and combined impact\\/abrasive conditions  

Microsoft Academic Search

Within this work, the effect of carbide degradation in a WC\\/W2C reinforced Ni-based hardfacing was assessed under abrasive and combined impact\\/abrasive conditions. In view of the above, a WC\\/W2C reinforced Ni-based hardfacing was deposited by plasma transferred arc (PTA) welding using different welding currents. Microstructure was characterised by quantitative metallography to determine specific structural parameters: mean carbide diameter and carbide

C. Katsich; E. Badisch

2011-01-01

231

Determining dynamically active abrasive particles in the media used in centrifugal force assisted abrasive flow machining process  

Microsoft Academic Search

Abrasive flow machining (AFM) is a relatively new non-traditional process in which a semisolid media consisting of abrasive\\u000a particles and a flexible polymer carrier is extruded through or across the component to be machine finished. This process\\u000a is capable of providing excellent surface finishes on a wide range of simple as well as intricated shaped components. Low\\u000a material removal rate

R. S. Walia; H. S. Shan; P. Kumar

2008-01-01

232

Self-modulating abrasive medium and its application to abrasive flow machining for finishing micro channel surfaces  

Microsoft Academic Search

This study developed a self-modulating abrasive medium whose viscosity and fluidity can be adjusted during the processing\\u000a period. The complex micro channel was fabricated on the stainless steel (SUS304) by using wire electrical discharge machining\\u000a (wire-EDM). An experiment of employing abrasive flow machining (AFM) was conducted to evaluate the characteristics of various\\u000a levels of roughness and finishing of the micro

Hsinn-Jyh Tzeng; Biing-Hwa Yan; Rong-Tzong Hsu; Yan-Cherng Lin

2007-01-01

233

Blast furnace injection symposium: Proceedings  

SciTech Connect

These proceedings contain 14 papers related to blast furnace injection issues. Topics include coal quality, coal grinding, natural gas injection, stable operation of the blast furnace, oxygen enrichment, coal conveying, and performance at several steel companies. All papers have been processed separately for inclusion on the data base.

NONE

1996-12-31

234

A mouse model of ocular blast injury that induces closed globe anterior and posterior pole damage.  

PubMed

We developed and characterized a mouse model of primary ocular blast injury. The device consists of: a pressurized air tank attached to a regulated paintball gun with a machined barrel; a chamber that protects the mouse from direct injury and recoil, while exposing the eye; and a secure platform that enables fine, controlled movement of the chamber in relation to the barrel. Expected pressures were calculated and the optimal pressure transducer, based on the predicted pressures, was positioned to measure output pressures at the location where the mouse eye would be placed. Mice were exposed to one of three blast pressures (23.6, 26.4, or 30.4 psi). Gross pathology, intraocular pressure, optical coherence tomography, and visual acuity were assessed 0, 3, 7, 14, and 28 days after exposure. Contralateral eyes and non-blast exposed mice were used as controls. We detected increased damage with increased pressures and a shift in the damage profile over time. Gross pathology included corneal edema, corneal abrasions, and optic nerve avulsion. Retinal damage was detected by optical coherence tomography and a deficit in visual acuity was detected by optokinetics. Our findings are comparable to those identified in Veterans of the recent wars with closed eye injuries as a result of blast exposure. In summary, this is a relatively simple system that creates injuries with features similar to those seen in patients with ocular blast trauma. This is an important new model for testing the short-term and long-term spectrum of closed globe blast injuries and potential therapeutic interventions. PMID:22504073

Hines-Beard, Jessica; Marchetta, Jeffrey; Gordon, Sarah; Chaum, Edward; Geisert, Eldon E; Rex, Tonia S

2012-06-01

235

A mouse model of ocular blast injury that induces closed globe anterior and posterior pole damage  

PubMed Central

We developed and characterized a mouse model of primary ocular blast injury. The device consists of: a pressurized air tank attached to a regulated paintball gun with a machined barrel; a chamber that protects the mouse from direct injury and recoil, while exposing the eye; and a secure platform that enables fine, controlled movement of the chamber in relation to the barrel. Expected pressures were calculated and the optimal pressure transducer, based on the predicted pressures, was positioned to measure output pressures at the location where the mouse eye would be placed. Mice were exposed to one of three blast pressures (23.6, 26.4, or 30.4psi). Gross pathology, intraocular pressure, optical coherence tomography, and visual acuity were assessed 0, 3, 7, 14, and 28 days after exposure. Contralateral eyes and non-blast exposed mice were used as controls. We detected increased damage with increased pressures and a shift in the damage profile over time. Gross pathology included corneal edema, corneal abrasions, and optic nerve avulsion. Retinal damage was detected by optical coherence tomography and a deficit in visual acuity was detected by optokinetics. Our findings are comparable to those identified in Veterans of the recent wars with closed eye injuries as a result of blast exposure. In summary, this is a relatively simple system that creates injuries with features similar to those seen in patients with ocular blast trauma. This is an important new model for testing the short-term and long-term spectrum of closed globe blast injuries and potential therapeutic interventions. PMID:22504073

Hines-Beard, Jessica; Marchetta, Jeffrey; Gordon, Sarah; Chaum, Edward; Geisert, Eldon E.; Rex, Tonia S.

2012-01-01

236

Computer assisted blast design and assessment tools  

SciTech Connect

In general the software required by a blast designer includes tools that graphically present blast designs (surface and underground), can analyze a design or predict its result, and can assess blasting results. As computers develop and computer literacy continues to rise the development of and use of such tools will spread. An example of the tools that are becoming available includes: Automatic blast pattern generation and underground ring design; blast design evaluation in terms of explosive distribution and detonation simulation; fragmentation prediction; blast vibration prediction and minimization; blast monitoring for assessment of dynamic performance; vibration measurement, display and signal processing; evaluation of blast results in terms of fragmentation; and risk and reliability based blast assessment. The authors have identified a set of criteria that are essential in choosing appropriate software blasting tools.

Cameron, A.R. [Golder Associates Ltd., Sudbury, Ontario (Canada); Kleine, T.H. [Golder Associates Inc., Seattle, WA (United States); Forsyth, W.W. [Golder Associates Ltd., Vancouver, British Columbia (Canada)

1995-12-31

237

HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM  

SciTech Connect

The objective of this project is to improve the productivity and lower the expense of existing vacuum blasting technology. This technology is used to remove radioactive contamination, PCBs, and lead-based paint and provides worker protection by continuously recycling the material and dust for the decontamination tasks. The proposed work would increase the cleaning rate and provide safe and cost-effective decontamination of the DOE sites. This work focuses on redesigning and improving existing vacuum blasting technology including blast head nozzles, ergonomic handling of the blast head by reducing its weight; brush-ring design, vacuum level regulator, efficiency of the dust separator, and operational control sensors. The redesign is expected to enhance the productivity and economy of the vacuum blasting system by at least 50% over current vacuum blasting systems. There are three phases in the project. Phase I consists of developing and testing mathematical models. Phase II consists of pre-prototype design and fabrication and pre-prototype unit testing. Phase III consists of prototype design and field verification testing. In phase I, mathematical models are developed and analyzed for the nozzle, blast head, wind curtain, and dust separator, first as individual devices and then combined as an integrated model. This allows study of respective airflow and design parameters. The Contractor shall, based on the results of the mathematical modeling studies, design experimental models of the components and test these models. In addition, the Contractor shall develop sensors to detect the relationship of the blast head to the blast surfaces and controls to minimize the dependency on an operator's skill and judgment to obtain optimum positioning, as well as real-time characterization sensors to determine as the blast head is moving the depth to which coatings must be removed, thereby improving production and minimizing waste. In phase II, the Contractor shall design and construct a pre-prototype of the nozzle, blast head with wind curtain, sensors, and dust separator and test this system to assess the performance of the new design under controlled conditions at the contractor's facility. In phase III, the Contractor shall design and construct a prototype of the High Productivity Vacuum Blasting System, based on the results of the pre-prototype design and testing performed. This unit will be a full-scale prototype and will be tested at a designated Department of Energy (DOE) facility. Based on the results, the system performance, the productivity, and the economy of the improved vacuum blasting system will be evaluated.

William S. McPhee

1999-05-31

238

Noise and blast  

NASA Technical Reports Server (NTRS)

Noise and blast environments are described, providing a definition of units and techniques of noise measurement and giving representative booster-launch and spacecraft noise data. The effects of noise on hearing sensitivity and performance are reviewed, and community response to noise exposure is discussed. Physiological, or nonauditory, effects of noise exposure are also treated, as are design criteria and methods for minimizing the noise effects of hearing sensitivity and communications. The low level sound detection and speech reception are included, along with subjective and behavioral responses to noise.

Hodge, D. C.; Garinther, G. R.

1973-01-01

239

Abrasion of Candidate Spacesuit Fabrics by Simulated Lunar Dust  

NASA Technical Reports Server (NTRS)

A protocol has been developed that produced the type of lunar soil abrasion damage observed on Apollo spacesuits. This protocol was then applied to four materials (Kevlar (DuPont), Vectran (Kuraray Co., Ltd.), Orthofabric, and Tyvek (DuPont)) that are candidates for advanced spacesuits. Three of the four new candidate fabrics (all but Vectran) were effective at keeping the dust from penetrating to layers beneath. In the cases of Kevlar and Orthofabric this was accomplished by the addition of a silicone layer. In the case of Tyvek, the paper structure was dense enough to block dust transport. The least abrasive damage was suffered by the Tyvek. This was thought to be due in large part to its non-woven paper structure. The woven structures were all abraded where the top of the weave was struck by the abrasive. Of these, the Orthofabric suffered the least wear, with both Vectran and Kevlar suffering considerably more extensive filament breakage.

Gaier, James R.; Meador, Mary Ann; Rogers, Kerry J.; Sheehy, Brennan H.

2009-01-01

240

Study of Dominant Factors Affecting Cerchar Abrasivity Index  

NASA Astrophysics Data System (ADS)

The Cerchar abrasion index is commonly used to represent rock abrasion for estimation of bit life and wear in various mining and tunneling applications. Although the test is simple and fast, there are some discrepancies in the test results related to the equipment used, condition of the rock surface, operator skills, and procedures used in conducting and measuring the wear surface. This paper focuses on the background of the test and examines the influence of various parameters on Cerchar testing including pin hardness, surface condition of specimens, petrographical and geomechanical properties, test speed, applied load, and method of measuring wear surface. Results of Cerchar tests on a set of rock specimens performed at different laboratories are presented to examine repeatability of the tests. In addition, the preliminary results of testing with a new device as a potential alternative testing system for rock abrasivity measurement are discussed.

Rostami, Jamal; Ghasemi, Amireza; Alavi Gharahbagh, Ehsan; Dogruoz, Cihan; Dahl, Filip

2014-09-01

241

A Robust Helical Abrasive Flow Machining (HLX-AFM) Process  

NASA Astrophysics Data System (ADS)

Abrasive flow machining (AFM) is a fine finishing process in which an abrasives laden semi-solid paste is used for finishing of internal inaccessible recesses or surfaces. Recently, several modifications in the tooling with/without additional machining action have been tried for increasing the material removal in the AFM. The present study is about a novel development in the AFM process, towards the enhancement of material removal rate while polishing the internal cylindrical surfaces. The modified process is termed as helical abrasive flow machining process (HLX-AFM). Taguchi's quality engineering approach has been applied to the developed HLX-AFM process, leading to the optimization of various process parameters and thus the development of a robust machining process with significantly enhanced material removal.

Brar, B. S.; Walia, R. S.; Singh, V. P.; Sharma, M.

2013-01-01

242

30 CFR 77.1300 - Explosives and blasting.  

Code of Federal Regulations, 2010 CFR

...UNDERGROUND COAL MINES Explosives and Blasting § 77.1300 Explosives and blasting. (a) No explosives, blasting agent, detonator, or any other related blasting device or material shall be stored, transported, carried, handled, charged,...

2010-07-01

243

Field evidence of two-phase abrasion process  

NASA Astrophysics Data System (ADS)

The rounded shape of river rocks is clear evidence that abrasion due to bed load transport is a significant agent for mass loss. Its contribution to downstream fining, however, is typically assumed to be negligible - as diminution trends may be explained solely by size-selective transport. A recent theory has predicted that pebble abrasion occurs in two well separated phases: in Phase 1, an intially-polyhedral pebble rounds to the shape of an inscribed ellipsoid without any change in axis dimensions; in Phase II, axis dimensions are slowly reduced. Importantly, Phase I abrasion means that an initially-blocky pebble may lose up to half its mass without any apparent change in 'size', which is only measured as the length of a single pebble axis by most field researchers. We hypothesize that field studies have significantly underestimated the importance of abrasion because they do not quantify pebble shape, and we set out to demonstrate that two-phase abrasion occurs in a natural stream. Our study examines downstream trends in pebble size and shape along a 10-km stretch of the Rio Mameyes within the Luquillo Critical Zone observatory, where volcaniclastic cobbles and boulders are transported by bed load at slopes up to 10%. The upper reaches of the stream consist of alluviated bedrock valleys that preclude sediment storage and thus minimize size-selective transport, which allows us to isolate the effects of abrasion. The lower 5 km is an alluvial river in which size-selective transport becomes operative. We quantified the shape and size of thousands of pebbles along the profile using hand and image-based techniques. The data provide the first field validation of two-phase abrasion; in the bedrock reaches, pebbles clearly evolve toward ellipsoids without any significant change in axis dimensions (rounding), while in the lower reaches pebbles slowly reduce their axis dimensions with little or no change in roundness. Results also show that shape metrics determined from two-dimensional (2D) imaging provide an adequate representation of the 3D evolution. In particular, the 2D curvature distribution is a sensitive metric of pebble shape, and is strongly related to the recently proposed 'equilibrium points' determined from 3D hand measurements. Although changes in pebble axis dimensions appear to be dominated by size-selective transport, shape data reveal that abrasion produces significant mass loss of pebbles. This mass loss affects both the mobility of the pebbles, and also produces substantial quantities of sand and silt that contribute to floodplain and ocean deposition downstream.

Miller, K. L.; Szabo, T.; Jerolmack, D. J.; Domokos, G.

2013-12-01

244

Advances in composite machining with abrasive-waterjets  

NASA Astrophysics Data System (ADS)

Abrasive-waterjets are being used in many composite trimming applications. The macro morphology and geometrical features, such as kerf taper or waviness of cuts produced in composites are not different than those observed in other materials. However, depending on the composite structure, micro effects may be significantly different. This paper, an extension of a previously published work, presents new data and observations on linear cutting, turning, drilling, and milling of composites. In general, the abrasive-waterjet is shown to allow accurate control of the machining process; machining accuracies of 0.025 mm have been demonstrated.

Hashish, M.

245

Polishing is made cheaper by disposable diamond-impregnated abrasive cloth  

NASA Technical Reports Server (NTRS)

Diamond impregnated abrasive cloth eliminated expensive diamond pastes and was economically disposed of to avoid contamination. Cloth was spunbonded nylon, but any napless fabric could be used. Cloth was sprayed with diamond abrasive gel.

Harper, F. J.

1972-01-01

246

Technique for abrasive cutting of thick-film conductors for hybrid circuits  

NASA Technical Reports Server (NTRS)

Abrasive jet technique, producing prototype conductor networks for thick-film hybrid microcircuits, does not require screening and fixing procedures. Pantograph engraver is used to perform abrasive cutting of the conductor network.

Nugent, J. B.; Palermo, J. S.

1969-01-01

247

The material and energy flow through the abrasive waterjet machining and recycling processes  

E-print Network

The purpose of this thesis was to investigate the material and energy flow through the abrasive waterjet machine and the WARD recycling machine. The goal was to track all of the material, water, abrasive, energy, air, and ...

Kurd, Michael Omar, 1982-

2004-01-01

248

Designing a low cost XY stage for abrasive water jet cutting  

E-print Network

This thesis guides the reader through the design of an inexpensive XY stage for abrasive water jet cutting machine starting with a set of functional requirements and ending with a product. Abrasive water jet cutting allows ...

Abu Ibrahim, Fadi, 1980-

2004-01-01

249

Model of the abrasive wear of HVOF deposited Cr3C2-NiCr coating  

Microsoft Academic Search

Based on the abrasive wear theory of composite materials in the condition of equal pressure, the coating microstructure and abrasive wear condition, the model for characterization the abrasive wear behavior of HVOF sprayed Cr3C2-NiCr coating was proposed. By examination of the morphology of the different area of worn surface, this model was confirmed. It is shown the abrasive wear of

Gangchang Ji; Hongtao Wang; Qingyu Chen; Wei Fu; Changjiu Li

2010-01-01

250

Micromechanical manufacturing of abrasive surfaces for fundamental studies on wear and grinding  

Microsoft Academic Search

An etching procedure has been developed with the objective to produce silicon abrasive surfaces in a controlled and reproducible way. These surfaces are intended for studies of fundamental aspects of abrasion. The procedure is based on techniques commonly used for manufacturing of silicon micro mechanical structures. The resulting surface is controlled with respect to abrasive tip shape, tip size and

Rickard Gåhlin; Staffan Jacobson

1998-01-01

251

An energetic approach to abrasive wear of a martensitic stainless steel  

Microsoft Academic Search

Abrasive wear is the most common type of wear that causes failure of machine elements. Examinations of abraded surfaces revealed presence of embedded particles and grooves elongated along the sliding direction. This indicates that, there are two sequential stages of an abrasion process. In the first stage, asperities on the hard surface and\\/or hard abrasive grains penetrate into the soft

U. Pamuk; M. Baydo?an; B. Niluefer; H. Çimeno?lu

2000-01-01

252

Abrasive stripping voltammetry of silver and tin at boron-doped diamond electrodes  

Microsoft Academic Search

Abrasive stripping voltammetry, using chemical vapour deposition (CVD) diamond electrodes and reference substrates comprising silver and tin, has been investigated. The abrasion process produced metallic particulates on the electrode surface, and both the mechanical and electrical contact were sensitively dependent on the abrasive force used. Only a small fraction of the material transferred was removed during electrochemical stripping. The silver

Arnab Chatterjee; Richard Wiltshire; Katherine B. Holt; Richard G. Compton; John S. Foord; Frank Marken

2002-01-01

253

ABRASION RESISTANCE OF CONCRETE AS INFLUENCED BY INCLUSION OF FLY ASH  

E-print Network

ABRASION RESISTANCE OF CONCRETE AS INFLUENCED BY INCLUSION OF FLY ASH Tarun R. Naik*, Shiw S. Singh abrasion resistance of high-volume fly ash concrete. A reference plain portland cement concrete of cement replacements (50 and 70%) with an ASTM Class C fly ash. Abrasion tests were carried out using

Wisconsin-Milwaukee, University of

254

Design and development of the magnetorheological abrasive flow finishing (MRAFF) process  

Microsoft Academic Search

A new precision finishing process for complex internal geometries using smart magnetorheological polishing fluid is developed. Magnetorheological abrasive flow finishing (MRAFF) process provides better control over rheological properties of abrasive laden magnetorheological finishing medium. Magnetorheological (MR) polishing fluid comprises of carbonyl iron powder and silicon carbide abrasives dispersed in the viscoplastic base of grease and mineral oil; it exhibits change

Sunil Jha; V. K. Jain

2004-01-01

255

Prediction system of magnetic abrasive finishing (MAF) on the internal surface of cylindrical tube  

Microsoft Academic Search

This study mainly used the way of the magnetic abrasive finishing (MAF) to explore the cylindrical tube of stainless steel SUS304 related to the processing characteristic and the prediction system. The self-make adjustable electricity polishing mechanism was assembled on the magnetic abrasive machine. The magnetic abrasive which was consisted of the sintered iron and Aluminum Oxide powder filled in the

Ching-Lien Hung; Wei-Liang Ku; Lieh-Dai Yang; Han-Ming Chow

2010-01-01

256

Mechanism of Surface Finishing in Ultrasonic-Assisted Magnetic Abrasive Finishing Process  

Microsoft Academic Search

Ultrasonic-assisted magnetic abrasive finishing (UAMAF) integrates the use of ultrasonic vibrations and magnetic abrasive finishing (MAF) processes to finish surfaces of nanometer order within a minute's time. The present study emphasizes the mechanism of surface finishing in UAMAF. This article reports the study of the microscopic changes in the surface texture resulting from interaction of abrasives with ground workpiece surface.

Rahul S. Mulik; Pulak M. Pandey

2010-01-01

257

ANALYSIS OF PERFORMANCE OF PULSATING FLEXIBLE MAGNETIC ABRASIVE BRUSH (P-FMAB)  

Microsoft Academic Search

Direct current magnetic abrasive finishing process provides hardly any stirring effect on static flexible magnetic abrasive brush (S-FMAB). Continuous use of S-FMAB and absence of stirring leads to dullness of abrasive cutting edges resulting in low finishing rate. To overcome this weakness of the process, the FMAB has been made pulsating using pulse direct current (DC) power supply. Empirical models

V. K. Jain; D. K. Singh; V. Raghuram

2008-01-01

258

Analysis of surface texture generated by a flexible magnetic abrasive brush  

Microsoft Academic Search

The application of magnetic field in the control of manufacturing processes has become of interest in recent past. In magnetic abrasive finishing (MAF) process, magnetic force plays a dominant role in the formation of flexible magnetic abrasive brush (FMAB) and developing abrasion pressure. The process is still in its infancy in many respects. Most of the previous research has explored

Dhirendra K. Singh; V. K. Jain; V. Raghuram; R. Komanduri

2005-01-01

259

Wear 252 (2002) 322331 A physically-based abrasive wear model for composite materials  

E-print Network

Wear 252 (2002) 322­331 A physically-based abrasive wear model for composite materials Gun Y. Leea 2001 Abstract A simple physically-based model for the abrasive wear of composite materials is presented-body (pin-on-drum) abrasive wear tests performed on a model aluminum particulate-reinforced epoxy

Ritchie, Robert

260

Some Observations on Erosive-Abrasive Wear of Metallic Surfaces in Particular Geometries  

Microsoft Academic Search

A study on erosive-abrasive wear of metallic surfaces by solid particles entrained in a liquid is presented for two cases: first, an abrasive jet impinging on a metallic plate, and second, erosion of a two-dimensional bend by a particle suspension flow. To determine the profile and amount of erosion, we combined the mechanics of abrasive suspensions in a liquid flow

M. T. Benchaita

1988-01-01

261

Parametric Optimization of Centrifugal Force-Assisted Abrasive Flow Machining (CFAAFM) by the Taguchi Method  

Microsoft Academic Search

Extrusion honing, known as abrasive flow machining (AFM), deburrs, polishes, and radiuses surfaces and edges by flowing an abrasive-laden media over these areas. The process is particularly used on internal shapes that are difficult to process by other nonconventional machining processes. Because abrasive action occurs only in areas where the flow is restricted, tooling is used to direct the media

R. S. Walia; H. S. Shan; Pradeep Kumar

2006-01-01

262

PROCESS MONITORING OF ABRASIVE FLOW MACHINING USING A NEURAL NETWORK PREDICTIVE MODEL  

E-print Network

PROCESS MONITORING OF ABRASIVE FLOW MACHINING USING A NEURAL NETWORK PREDICTIVE MODEL Sarah S. Y of a neural network based process monitor and off-line controller for abrasive flow machining of automotive parameter of interest, air flow rate through the manifold. Keywords: Abrasive flow machining, neural

Smith, Alice E.

263

Study on abrasive flow ultra-precision polishing technology of small hole  

Microsoft Academic Search

The self-designed Abrasive Flow Machine and Clamp are introduced in this paper. The technology issues of abrasive flow medium selection and process parameters settings are discussed. We conducted the experiment on the small hole with diameter of 0.15 mm. Through the experiment, the best process parameters of the Abrasive Flow Machining of small hole are obtained.

Shuren Zhang; Weina Liu; Lifeng Yang; Chunfeng Zhu; Chun Li; Junye Li; Xin Li

2009-01-01

264

Rotational abrasive flow finishing (RAFF) process and its effects on finished surface topography  

Microsoft Academic Search

The present study focus on abrasive flow finishing (AFF), a process that finishes complex internal and external geometries with the help of viscoelastic abrasive medium, while keeping in mind its low finish and material removal rates (MRR). Researchers have often strived to improve finishing rate and MRR. As an attempt to overcome the said limitations, this paper discusses rotational abrasive

M. Ravi Sankar; V. K. Jain; J. Ramkumar

2010-01-01

265

Measurements on 5:1 Scale Abrasive Water Jet Cutting Head Models  

E-print Network

There is a vast potential market for high precision parts manufactured by abrasive water jet (AWJ) machining and measurement methods are discussed in this paper. Keywords: Multiphase-flow measurement, abrasive water jet Fluorescence m Mass, kg m° Mass flow, kg/s m* abr Dimensionless abrasive mass flow, m* abr = m°abr/m°water PIV

266

Cascade-Correlation Neural Network Modeling of the Abrasive Flow Machining Process  

E-print Network

1 Cascade-Correlation Neural Network Modeling of the Abrasive Flow Machining Process Sarah S. Y the abrasive flow machining (AFM) of automotive engine air intake manifolds using a cascade-correlation neural: Abrasive Flow Machining, Neural Network, Cascade Learning, Process Control, Engine Manifold, Cross

Smith, Alice E.

267

Optimization of Process Parameters in CFRP Machining with Diamond Abrasive Cutters  

E-print Network

Optimization of Process Parameters in CFRP Machining with Diamond Abrasive Cutters Aude BOUDELIER.garnier@irccyn.ec-nantes.fr, benoit.furet@irccyn.ec-nantes.fr Keywords: CFRP laminate composite; trimming; diamond abrasive cutter roughness. Feedrate must respect cutting limitations due to CFRP removal mechanisms with abrasive cutters

Paris-Sud XI, Université de

268

Method for the characterization of the abrasion induced nanoparticle release into air from surface coatings  

Microsoft Academic Search

A novel method for the quantification of the nanoparticle release into air from surface coatings was developed. The method is based on the combination of a defined abrasion process with highly sensitive methods to quantify airborne particle concentration. A standardized system for abrasion testing was employed to adjust a defined wear process.Details of the abrasion system are presented in combination

Manuel Vorbau; Lars Hillemann; Michael Stintz

2009-01-01

269

PENETRATION ABILITY OF ABRASIVE WATERJETS IN CUTTING OF ALUMINUM-SILICON CARBIDE PARTICULATE METAL MATRIX COMPOSITES  

Microsoft Academic Search

This article presents a set of studies performed on aluminum-silicon carbide particulate metal matrix composites prepared by adding 5, 10, 15 and 20% of SiC in aluminum alloy and processed with abrasive water jets that are formed with garnet and silicon carbide abrasives of 80 mesh size. These studies are essentially meant to assess the penetration ability of abrasive water

S. Srinivas; N. Ramesh Babu

2012-01-01

270

Porcine head response to blast.  

PubMed

Recent studies have shown an increase in the frequency of traumatic brain injuries related to blast exposure. However, the mechanisms that cause blast neurotrauma are unknown. Blast neurotrauma research using computational models has been one method to elucidate that response of the brain in blast, and to identify possible mechanical correlates of injury. However, model validation against experimental data is required to ensure that the model output is representative of in vivo biomechanical response. This study exposes porcine subjects to primary blast overpressures generated using a compressed-gas shock tube. Shock tube blasts were directed to the unprotected head of each animal while the lungs and thorax were protected using ballistic protective vests similar to those employed in theater. The test conditions ranged from 110 to 740?kPa peak incident overpressure with scaled durations from 1.3 to 6.9?ms and correspond approximately with a 50% injury risk for brain bleeding and apnea in a ferret model scaled to porcine exposure. Instrumentation was placed on the porcine head to measure bulk acceleration, pressure at the surface of the head, and pressure inside the cranial cavity. Immediately after the blast, 5 of the 20 animals tested were apneic. Three subjects recovered without intervention within 30?s and the remaining two recovered within 8?min following respiratory assistance and administration of the respiratory stimulant doxapram. Gross examination of the brain revealed no indication of bleeding. Intracranial pressures ranged from 80 to 390?kPa as a result of the blast and were notably lower than the shock tube reflected pressures of 300-2830?kPa, indicating pressure attenuation by the skull up to a factor of 8.4. Peak head accelerations were measured from 385 to 3845 G's and were well correlated with peak incident overpressure (R(2)?=?0.90). One SD corridors for the surface pressure, intracranial pressure (ICP), and head acceleration are presented to provide experimental data for computer model validation. PMID:22586417

Shridharani, Jay K; Wood, Garrett W; Panzer, Matthew B; Capehart, Bruce P; Nyein, Michelle K; Radovitzky, Raul A; Bass, Cameron R 'dale'

2012-01-01

271

Blast From the Past  

NSDL National Science Digital Library

A recently recovered deep-sea core supports theories that an asteroid collided with the earth 65 million years ago, around the time of the extinction of the dinosaurs. The Smithsonian Institution National Museum of Natural History's new site, Blast from the Past, contains details on this cataclysmic event. Colorful graphics provide conceptual illustrations of the asteroid impact and aftermath, accompanied by photographs of the deep-sea core. Text summaries, followed by bibliographic references, describe the asteroid hypothesis, the Cretaceous/Tertiary (K/T) boundary, and the utility of deep-sea cores. With links to other paleobiological sites and related museum exhibits, this site is a useful resource for those wanting to know more about fateful asteroid impacts.

272

ABRASIVE WEAR OF ALUMINIUM-MAGNESIUM ALLOYS AT VARIOUS TEMPERATURES  

Microsoft Academic Search

The abrasive wear and hot'' hardness of alloys of aluminium and ; magnesium of various concentrations was investigated at various temperatures. ; Specimens, cast into a chill mold and subsequently annealed, were studied. They ; had the following concentrationsn: 0, 1, nesium, the remainder being technically ; pure aluminum. The following temperatures were selected for testing: specimen of ; 5

V. N. Kashcheyev; L. N. Voytsekhovksaya

1959-01-01

273

Innovative decontamination technology by abrasion in vibratory vessels  

SciTech Connect

Available in abstract form only. Full text of publication follows: The possibility of using conventional vibratory vessel technology as a decontamination technique is the motivation for the development of this project. The objective is to explore the feasibility of applying the vibratory vessel technology for decontamination of radioactively-contaminated materials such as pipes and metal structures. The research and development of this technology was granted by the U.S. Department of Energy (DOE). Abrasion processes in vibratory vessels are widely used in the manufacture of metals, ceramics, and plastics. Samples to be treated, solid abrasive media and liquid media are set up into a vessel. Erosion results from the repeated impact of the abrasive particles on the surface of the body being treated. A liquid media, generally detergents or surfactants aid the abrasive action. The amount of material removed increases with the time of treatment. The design and construction of the machine were provided by Vibro, Argentina private company. Tests with radioactively-contaminated aluminum tubes and a stainless steel bar, were performed at laboratory level. Tests showed that it is possible to clean both the external and the internal surface of contaminated tubes. Results show a decontamination factor around 10 after the first 30 minutes of the cleaning time. (authors)

Fabbri, Silvio; Ilarri, Sergio [National Atomic Energy Commission - CNEA, Avda. del Libertador 8250, CP 1429, Ciudad Autonoma de Buenos Aires (Argentina)

2007-07-01

274

Rotating wheel abrasion of WC\\/Co hardmetals  

Microsoft Academic Search

The abrasion resistance of a range of hardmetals has been examined in two different types of rotating wheel wear test. These were an ASTM B611 steel wheel test, and a modified ASTM G65 test system. The aim of the work was to examine the effects of changing the conditions of the test on the results that were obtained. The parameters

A. J. Gant; M. G. Gee; B. Roebuck

2005-01-01

275

The effect of microstructure on abrasive wear of hardfacing alloys  

Microsoft Academic Search

Hardfacing is one of the most useful and economical ways to improve the performance of components submitted to severe wear conditions. A study was made to compare the microstructure and abrasion resistance of hardfacing alloys reinforced with primary chromium carbides, complex carbides or tungsten carbides. The hardfacing alloys were deposited onto ASTM A36 carbon steel plates by a shielded metal

M. F. Buchely; J. C. Gutierrez; L. M. León; A. Toro

2005-01-01

276

Estimating rock compressive strength from Rock Abrasion Tool (RAT) grinds  

E-print Network

carries a Rock Abrasion Tool (RAT) whose intended use was to abrade the outer surfaces of rocks to expose intact rocks. Applying this correlation to rocks abraded by Spirit's RAT, the results indicate a large pro- vides a wealth of information about the physical properties of the target being abraded. Motor

Hutyra, Lucy R.

277

Abrasion, weathering and mobility of lead in Florida  

E-print Network

abrasion of Pb bullets � Field sampling of newly opened shooting range � Weathering study involving abraded Pb � Influence of soil properties and amendments on weathering of abraded Pb � Desorption of Pb from mass of Pb abraded per 22-caliber bullet- 41.2 mg or 1.5% of bullet mass ­ All but one SPLP Pb conc

Ma, Lena

278

Metastable austenitic stainless steel tool for magnetic abrasive finishing  

Microsoft Academic Search

Through selective heat treatment, a metastable austenitic stainless steel tool can be fabricated to exhibit alternating magnetic and nonmagnetic regions. Magnetic abrasive is attracted to the borders of the magnetic regions of the developed tool to create additional finishing points. In combination with a multiple pole-tip system, this unique magnetic property facilitates simultaneous finishing of multiple regions for shortening finishing

H. Yamaguchi; J. Kang; F. Hashimoto

2011-01-01

279

Effective Deburring of Micro Burr Using Magnetic Abrasive Finishing Method  

Microsoft Academic Search

Micro burrs formed in micro parts are not subject to be removed by the conventional deburring method for marco parts. Magnetic abrasive deburring method which was proved to be effective for small burrs are applied for deburring the micro burr in electric gun parts used in TV monitor. A specific magnetic inductor is designed and manufactured for this part. To

Jung Il Park; S.-L. Ko; Y. H. Hanh; Yuri M. Baron

2005-01-01

280

Statistical Analysis of Magnetic Abrasive Finishing (MAF) On Surface Roughness  

Microsoft Academic Search

Magnetic assisted finishing is one of the nontraditional methods of polishing that recently has been attractive for the researchers. This paper investigates the effects of some parameters such as rotational speed of the permanent magnetic pole, work gap between the permanent pole and the work piece, number of the cycles and the weight of the abrasive particles on aluminum surface

Mehrdad Givi; Alireza Fadaei Tehrani; Aminollah Mohammadi

2010-01-01

281

SUPERFINISHING OF ALLOY STEELS USING MAGNETIC ABRASIVE FINISHING PROCESS  

Microsoft Academic Search

Magnetic abrasive finishing (MAF) process is the one in which material is removed in such a way that surface finishing and deburring are performed simultaneously with the applied magnetic field in the finishing zone. The mechanism of superfinishing in any finishing process is widely focused by the knowledge of forces involved in the process. This paper reports the findings about

Dhirendra K. Singh; V. Raghuram

282

Parameter optimization in magnetic abrasive polishing for magnesium plate  

Microsoft Academic Search

This study aims to finish effectively the thin magnesium (AZ31) alloy plate that is usually very difficult to be polished by the conventional cutting processes because of their explosive and fragility properties. Reaction components on the workpiece surface roughness were measured after the magnetic abrasive polishing of the magnesium alloy plate. Taguchi experimental design method was adopted for evaluating the

Jae-Seob Kwak; Tae-Kyung Kwak

2010-01-01

283

Characterization and prediction of abrasive wear of powder composite materials  

Microsoft Academic Search

Composite materials produced by powder metallurgy provide a solution in many engineering applications where materials with high abrasion and erosion resistance are required. The actual wear behaviour of the material is associated with many external factors (particle size, velocity, angularity, etc.) and intrinsic material properties (hardness, toughness, Young modulus, etc.). Hardness and toughness properties of such tribomaterials are highly dependent

R. Veinthal; P. Kulu; J. Pirso; H. Käerdi

2009-01-01

284

A physically-based abrasive wear model for composite materials  

Microsoft Academic Search

A simple physically-based model for the abrasive wear of composite materials is presented based on the mechanics and mechanisms associated with sliding wear in soft (ductile)- matrix composites containing hard (brittle) reinforcement particles. The model is based on the assumption that any portion of the reinforcement that is removed as wear debris cannot contribute to the wear resistance of the

Gun Y. Lee; C. K. H. Dharan; R. O. Ritchie

2002-01-01

285

A physically-based abrasive wear model for composite materials  

Microsoft Academic Search

A simple physically-based model for the abrasive wear of composite materials is presented based on the mechanics and mechanisms associated with sliding wear in soft (ductile) matrix composites containing hard (brittle) reinforcement particles. The model is based on the assumption that any portion of the reinforcement that is removed as wear debris cannot contribute to the wear resistance of the

Gun Y. Lee; C. K. H. Dharan; Robert O. Ritchie

2001-01-01

286

Predicting the abrasive wear of ball bearings by lubricant debris  

Microsoft Academic Search

Solid debris particles in a lubricant can become entrained into the contacts of ball bearings. The particles damage the bearing surfaces. This can lead to rolling contact fatigue failure or material loss by three body abrasion. This work concentrates on modelling the later process for brittle debris materials. A brittle particle is crushed in the inlet region and the fragments

R. S Dwyer-Joyce

1999-01-01

287

An abrasive-wear model for undersea lightguide cable  

Microsoft Academic Search

An abrasive wear model for a cable, developed from the theory of material wear, is presented. This model is a modification of a model previously proposed by the author. The model is more accurate and general because it incorporates the frictional coefficient as a variable. The present model reduces to the former model when the frictional coefficient is set to

Percy S. Wu

1991-01-01

288

Nature of impact-abrasive wear of steel  

Microsoft Academic Search

The wear mechanism of steel from the standpoint of the thermofluctuation theory of fracture is considered. A model of the intensity of impact-abrasive wear of steel is presented, taking into account the impact self-action and the thermofluctuation properties of the material. Justification is given for the study of tribotechnical problems including the foundations of strength physics.

G. M. Sorokin; S. P. Grigor'ev; A. G. Golova

1991-01-01

289

Influence of stress state on abrasive wear of steels  

Microsoft Academic Search

The resistance of materials to abrasive wear depends on many factors that can be generally classified as material-based or operating systembased. In the published wear models, the bulk stress state or stress history of worn material do not appear as influencing factors. Following the analogy with stress corrosion and fatigue, as well as with cyclic softening of steel materials, the

S. Spuzic; K. N. Strafford; C. Subramanian; L. Green

1995-01-01

290

Specific energy and temperature determination in abrasive flow machining process  

Microsoft Academic Search

A model has been proposed for the determination of specific energy and tangential forces in abrasive flow machining (AFM) process. It accounts for the process parameters of AFM e.g., grain size, applied pressure, hardness of workpiece material, number of cycles and number of active grains. Heat transfer in AFM has also been analysed considering heat flow to the workpiece and

Rajendra K Jain; V. K Jain

2001-01-01

291

Investigations into abrasive flow finishing of complex workpieces using FEM  

Microsoft Academic Search

Abrasive flow machining (AFM) process provides a high level of surface finish and close tolerances with an economically acceptable rate of surface generation for a wide range of industrial components. It is attempted to analyze the AFM process using finite element method (FEM) for finishing of external surfaces. To study the material removal mechanism of AFM, finite element model of

V. K. Jain; Rajani Kumar; P. M. Dixit; Ajay Sidpara

2009-01-01

292

Prediction of surface roughness during abrasive flow machining  

Microsoft Academic Search

An analytical model is proposed to simulate and predict the surface roughness for different machining conditions in abrasive flow machining (AFM). The kinematic analysis is used to model the interaction between grain and workpiece. Fundamental AFM parameters, such as the grain size, grain concentration, active grain density, grain spacing, forces on the grain, initial topography, and initial surface finish (R

V. K. Gorana; V. K. Jain; G. K. Lal

2006-01-01

293

Stochastic simulation of active grain density in abrasive flow machining  

Microsoft Academic Search

Abrasive flow machining can be applied to an impressive range of finishing operations economically and effectively. Both theoretical and experimental studies of the media topography are greatly hampered by the inherent random nature and the multiplicity of variables. A stochastic simulation model has been developed to determine the active grain density on the media surface which is in contact with

Rajendra K. Jain; V. K. Jain

2004-01-01

294

A neural network process model for abrasive flow machining operations  

Microsoft Academic Search

This paper describes the development of a predictive process modeling system for the abrasive flow machining (AFM) process. This process is used for polishing and surface removal of workpieces with an internal flow path. The core of the process modeling system is a set of neural network models that predicts surface finish and dimensional change. These neural network models are

Kimberly L. Petri; Richard E. Billo; Bopaya Bidanda

1998-01-01

295

Forces prediction during material deformation in abrasive flow machining  

Microsoft Academic Search

To study the finishing mechanism of abrasive flow machining (AFM), theoretical model of forces acting on a single grain has been developed. An experimental research has been carried out by measuring the axial force, radial force and active grain density during the AFM process. Results obtained from theoretical model for grain–workpiece interaction during material deformation have been compared with the

V. K. Gorana; V. K. Jain; G. K. Lal

2006-01-01

296

Modelling of abrasive flow machining process: a neural network approach  

Microsoft Academic Search

A simple neural network model for abrasive flow machining process has been established. The effects of machining parameters on material removal rate and surface finish have been experimentally analysed. Based on this analysis, model inputs and outputs were chosen and off-line model training using back-propagation algorithm was carried out. Simulation results confirm the feasibility of this approach and show a

R. K. Jain; V. K. Jain; P. K. Kalra

1999-01-01

297

Deburring of burrs in spring collets by abrasive flow machining  

Microsoft Academic Search

Micro burrs occurring inside the small and large diameters adversely affect the properties of products. Manual deburring of micro burrs in particular damages the processed surface and reduces production efficiency. In this study, spring collets made of chrome-molybdenum are used to test the deburring of the surface of collets including crossed micro grooves by abrasive flow machining.

Jeong-Du Kim; Kyung-Duk Kim

2004-01-01

298

Abrasion resistant active braze alloys for metal single layer technology  

Microsoft Academic Search

The technology of brazing a single layer of abrasive on to the surface of a grinding tool, metal single layer (MSL) technology, provides an alternative way to make use of the superabrasives diamond and cubic boron nitride in machining ceramic materials or super- alloys, cutting of construction materials, etc. For cer- tain applications of MSL bonded wheels, the grinding or

299

Materials Science Acceleration of Corrosion of Dental Amalgam by Abrasion  

Microsoft Academic Search

Dental amalgam shows passive behavior, but the protective film can be destroyed by abrasion. In this study, specimens of both low- and high-copper amalgam were abraded, and the effect on the corrosion behavior was examined. The electrochemical measurements showed that the corrosion rate was substantially increased, and that re-passivation was relatively slow.

M. Marek

1984-01-01

300

[Enamel abrasion and enamel tears by porcelain brackets].  

PubMed

Orthodontic brackets manufactured of poly- or monocrystalline alumina ceramics are aesthetically appealing, but unfortunately show disadvantages for clinical application primarily causing (1) Abrasions of the enamel of antagonistic teeth, and (2) Tear-outs of the underlying enamel through debonding. To determine whether hardness and/or textural and structural qualities of the ceramics (as characterized by SEM investigations) are responsible for the deleterious clinical effects of abrasion, the amount of decrease of the height of human enamel-molar-cusps was measured. Enamel loss was shown to be significantly more than 100 microns at 10 min. operating time in an abrasive testing device. Also debonding of the ceramic brackets proved to be problematic. Whereas metals and polymeric brackets allow some deflection of the material in addition to the tensile stress, separating the bracket from the enamel at the bracket-to-adhesive interface, or within the adhesive composite, the lacking workability in the ceramic brackets may induce a shift of the break-line during debonding to the adhesive-enamel interface or even into the dental enamel. Development and clinical application of ceramic brackets should improve safety for the enamel. Regardless of ceramic brand the abrasiveness endangers enamel through ceramic/enamel interferences. To avoid tear-out defects, brackets should debond at the ceramic-adhesive interface. PMID:2699879

Newesely, H; Rossiwall, B

1989-01-01

301

Analysis of magnetic abrasive finishing with slotted magnetic pole  

NASA Astrophysics Data System (ADS)

Magnetic Abrasive Finishing (MAF) is relatively a new finishing process among the advanced finishing processes in which the workpiece is kept in the magnetic field created by two poles of an electromagnet. The working gap between the workpiece and the magnet is filled with magnetic abrasive particles. A flexible magnetic abrasive brush is formed, acting as a multipoint cutting tool, due to the effect of magnetic field in the working gap. This process is capable of producing the surface finish of nanometer range. Most of the researchers have been using the electromagnet having a slot in it to improve the performance of the process but hardly any information is available about its effect on the process performance. This paper deals with the effect of a slot made in the electromagnet on the forces and surface quality during MAF. An experimental set-up is designed and fabricated for the measurement of the magnetic field distribution in the working gap. The magnetic field is simulated using a finite element model of the process. The magnetic field is also measured experimentally to validate the theoretical results. It indicates a good agreement between the experimental results and simulated values. The finite element method is further used for the evaluation of the magnetic force and surface quality during MAF. To our surprise it is found that the force under the slot is negative, even then process performance is improved. MAF process removes a very small amount of material by indentation and rotation of the magnetic abrasive particles in the circular tracks. Due to rotation of the magnetic abrasive flexible brush, grooves are formed on the workpiece surface which decides the surface profile after MAF. Surface quality is determined on the basis of the surface profile achieved by equating the volume of groove produced. These results show an improvement in finishing rate while using a slotted pole surface.

Jayswal, S. C.; Jain, V. K.; Dixit, P. M.

2004-06-01

302

Environmental effects of blast induced immissions  

SciTech Connect

The subject of the paper is blasting vibrations as sources of environmental molestations including acceptance level, complaint level and damage level, as well. In addition, the paper shows a comparison of international regulations and their problematical aspects. In consideration of blast induced immissions the subject shows that human annoyance has become an important place in blasting works. It provides a solution proposal how to minimize environmental effects of blasting works.

Schillinger, R.R. [Schillinger GmbH, Noerdlingen (Germany)

1996-12-01

303

Methodology of evaluation of abrasive tool wear with the use of laser scanning microscopy.  

PubMed

Grinding is one of the basic precise material removal methods. Abrasive and shape wear, as well as smearing of the tools' active surface handicap the processing results. The loss of cutting capacity in abrasive tools or alteration of their shape influences the surface quality and precision of the workpiece dimensions and its shape. Evaluation of the abrasive tool surface is the basic criterion of forecasting the tools' durability and the process results. The applied method of laser scanning made determination of the surface coordinates and subsequently of its geometric features with micrometric accuracy possible. Using the information on the abrasive tool surface geometric structure, a methodology of evaluation of the level of changes in geometric features of the tool during the grinding process was developed. Criteria for evaluation of the level of abrasive grains attritious wear, the degree of smearing of the abrasive tool surface and evaluation of the cutting capability of the abrasive tools were determined. The developed method allowed for evaluation of the level of abrasive tools' wear, and subsequently formed foundations for assessment of the influence of the grinding parameters on the durability of abrasive tools, evaluation of the influence of the parameters of the process of shaping the abrasive tools' active surfaces on their geometric characteristics and evaluation of the level of correlation between the monitored process parameters and the degree of the abrasive tools' wear. PMID:23592189

Lipi?ski, Dariusz; Kacalak, Wojciech; Tomkowski, Robert

2014-01-01

304

Abrasive Wear Study of Rare Earth Modified Coatings by Statistical Method  

NASA Astrophysics Data System (ADS)

This paper describes the effect of combined addition of rare earth elements namely CeO2 and La2O3 in Ni-base alloy coatings. The rare earth addition refines microstructure, increases hardness, and abrasive wear resistance of coatings. The abrasive wear behavior of these coatings was investigated using four factors load ( L), abrasive size ( A), sliding speed ( S), and temperature ( T) with three levels of each factor using RSM. ANOVA was carried out to determine the significant factors and interactions. Investigation showed that the load, abrasive size, and sliding speed were the main significant factors while load and abrasive size, load and sliding speed, abrasive size and sliding speed were the main significant interactions. Thus, an abrasive wear model was developed in terms of significant factors and their significant interactions. The validity of the model was evaluated by conducting experiments under different conditions. A comparison of modeled and experimental results showed 3-8% error.

Sharma, Satpal

2012-09-01

305

Decontamination of surfaces by blasting with crystals of H{sub 2}O and CO{sub 2}  

SciTech Connect

A major mission of the US Department of Energy during the 1990s is site and environmental cleanup. In pursuit of this mission, numerous remediation projects are under way and many others are being planned at Oak Ridge National Laboratory (ORNL). In this report, tests using two proposed methods for decontaminating surfaces one using water ice crystals [Crystalline Ice Blast (CIB)], the other using dry ice crystals (CO{sub 2} Cleanblast{trademark}) -- are described. Both methods are adaptations of the commonly used sand blasting technology. The two methods tested differ from sand blasting in that the particles are not particularly abrasive and do not accumulate as particles in the wastes. They differ from each other in that the CO{sub 2} particles sublime during and after impact and the ice particles melt. Thus, the two demonstrations provide important information about two strong candidate decontamination methodologies. Each process was tested at ORNL using contaminated lead bricks and contaminated tools and equipment. Demonstrations with the prototype Crystalline Ice Blast and the CO{sub 2} Cleanblast systems showed that paint, grease, and oil can be removed from metal, plastic, asphalt, and concrete surfaces. Furthermore, removal of contamination from lead bricks was highly effective. Both processes were found to be less effective, under the conditions tested, with contaminated tools and equipment that had chemically bonded contamination or contamination located in crevices since neither technology abrades the substrates or penetrates deeply into crevices to remove particulates. Some process improvements are recommended.

Benson, C.E.; Parfitt, J.E.; Patton, B.D.

1995-02-01

306

Self inflicted corneal abrasions due to delusional parasitosis  

PubMed Central

The authors report a case of self inflicted bilateral corneal abrasions and skin damage due to ophthalmic and cutaneous delusional parasitosis. A male in his 50s presented with a 10 year history of believing that parasites were colonizing his skin and biting into his skin and eyes. The patient had received extensive medical evaluations that found no evidence that symptoms were due to a medical cause. He was persistent in his belief and had induced bilateral corneal abrasions and skin damage by using heat lamps and hair dryers in an attempt to disinfect his body. The patient was treated with olanzapine along with treatment for his skin and eyes. His delusional belief system persisted but no further damage to his eyes and skin was noted on initial follow-up. PMID:22689836

Meraj, Adeel; Din, Amad U; Larsen, Lynn; Liskow, Barry I

2011-01-01

307

Abrasion Testing of Critical Components of Hydrokinetic Devices  

SciTech Connect

The objective of the Abrasion Testing of Critical Components of Hydrokinetic Devices (Project) was to test critical components of hydrokinetic devices in waters with high levels of suspended sediment – information that is widely applicable to the hydrokinetic industry. Tidal and river sites in Alaska typically have high suspended sediment concentrations. High suspended sediment also occurs in major rivers and estuaries throughout the world and throughout high latitude locations where glacial inputs introduce silt into water bodies. In assessing the vulnerability of technology components to sediment induced abrasion, one of the greatest concerns is the impact that the sediment may have on device components such as bearings and seals, failures of which could lead to both efficiency loss and catastrophic system failures.

Worthington, Monty [ORPC Alaska] [ORPC Alaska; Ali, Muhammad [Ohio University] [Ohio University; Ravens, Tom [University of Alaska Anchorage] [University of Alaska Anchorage

2013-12-06

308

A physically-based abrasive wear model for composite materials  

SciTech Connect

A simple physically-based model for the abrasive wear of composite materials is presented based on the mechanics and mechanisms associated with sliding wear in soft (ductile) matrix composites containing hard (brittle) reinforcement particles. The model is based on the assumption that any portion of the reinforcement that is removed as wear debris cannot contribute to the wear resistance of the matrix material. The size of this non-contributing portion of the reinforcement is estimated by modeling the three primary wear mechanisms, specifically plowing, interfacial cracking and particle removal. Critical variables describing the role of the reinforcement, such as its relative size and the nature of the matrix/reinforcement interface, are characterized by a single contribution coefficient, C. Predictions are compared with the results of experimental two-body (pin-on drum) abrasive wear tests performed on a model aluminum particulate-reinforced epoxy matrix composite material.

Lee, Gun Y.; Dharan, C.K.H.; Ritchie, Robert O.

2001-05-01

309

Abrasive-waterjet machining of ceramic-coated materials  

NASA Astrophysics Data System (ADS)

This paper addresses an experimental investigation on the feasibility of using abrasive-waterjets (AWJs) for the precision drilling of small-diameter holes in advanced aircraft engine components. These components are sprayed with ceramic thermal barrier coating (TBC), and the required holes are typically 0.025 inch in diameter, with a drilling angle of 25 deg. The parameters of the AWJ were varied to study their effects on both quantitative and qualitative hole drilling parameters. The unique techniques of assisting the abrasive feed process, ramping the waterjet pressure, during drilling, and varying the jet dwell time after piercing were effectively implemented to control hole quality and size. The results of the experiments indicate the accuracy and repeatability of the AWJ technique in meeting the air flow and hole size requirements. Production parts were drilled for prototype engine testing.

Hashish, M.; Whalen, J.

1991-09-01

310

Microstructure and abrasive wear in silicon nitride ceramics  

SciTech Connect

It is well known that abrasive wear resistance is not strictly a materials property, but also depends upon the specific conditions of the wear environment. Nonetheless, characteristics of the ceramic microstructure do influence its hardness and fracture toughness and must, therefore, play an active role in determining howa ceramic will respond to the specific stress states imposed upon it by the wear environment. In this study, the ways in which composition and microstructure influence the abrasive wear behavior of six commercially-produced silicon nitride based ceramics are examined. Results indicate that microstructural parameters, such as matrix grain size and orientation, porosity, and grain boundary microstructure, and thermal expansion mismatch stresses created as the result of second phase formation, influence the wear rate through their effect on wear sheet formation and subsurface fracture. It is also noted that the potential impact of these variables on the wear rate may not be reflected in conventional fracture toughness measurements.

Dogan, Cynthia P.; Hawk, Jeffrey A.

2001-10-01

311

Abrasive wear properties of Cr-Cr3Si composites  

SciTech Connect

A series of composites based on the Cr?Cr3Si system, and containing between 50 and 100%Cr3Si, were fabricated by hot pressing. These composites have high stiffness, good thermal conductivity, excellent chemical resistance, and high temperature creep and oxidation resistance, making them potential candidates for hard-facing applications and cutting tools in harsh environments. In this study, the Cr?Cr3Si composites were abrasion tested at ambient temperatures in order to evaluate their wear properties. Single scratch tests were performed to give insight into material removal mechanisms. Although like most metal silicides, these materials behave in a brittle manner, the results of this study indicate that the addition of a ductile second phase (Cr) can enhance both their fracture toughness and abrasive wear resistance. The addition of 10% of the rare earth oxide Er2O3 improves the density of the composite, but has no apparent influence on the wear resistance.

Newkirk, J.W. (University of Missouri-Rolla); Hawk, Jeffrey A.

2001-10-01

312

Wheel Abrasion Experiment Metals Selection for Mars Pathfinder Mission  

NASA Technical Reports Server (NTRS)

A series of metals was examined for suitability for the Wheel Abrasion Experiment, one of ten microrover experiments of the Mars Pathfinder Mission. The seven candidate metals were: Ag, Al, Au, Cu, Ni, Pt, and W. Thin films of candidate metals from 0.1 to 1.0 micrometer thick were deposited on black anodized aluminum coupons by e-beam and resistive evaporation and chemical vapor deposition. Optical, corrosion, abrasion, and adhesion criteria were used to select Al, Ni, and Pt. A description is given of the deposition and testing of thin films, followed by a presentation of experimental data and a brief discussion of follow-on testing and flight qualification.

Hepp, Aloysius F.; Fatemi, Navid S.; Wilt, David M.; Ferguson, Dale C.; Hoffman, Richard; Hill, Maria M.; Kaloyeros, Alain E.

1996-01-01

313

Evaluation of Gritting Strategies for High Angle of Attack Using Wind Tunnel and Flight Test Data for the F/A-18  

NASA Technical Reports Server (NTRS)

A subsonic study of high-angle-of-attack gritting strategies was undertaken with a 0.06-scale model of the F/A-18, which was assumed to be typical of airplanes with smooth-sided forebodies. This study was conducted in the Langley 7- by 10-Foot High-Speed Tunnel and was intended to more accurately simulate flight boundary layer characteristics on the model in the wind tunnel than would be possible by using classical, low-angle-of-attack gritting on the fuselage. Six-component force and moment data were taken with an internally mounted strain-gauge balance, while pressure data were acquired by using electronically scanned pressure transducers. Data were taken at zero sideslip over an angle-of-attack range from 0 deg to 40 deg and, at selected angles of attack, over sideslip angles from -10 deg to 10 deg. Free-stream Mach number was fixed at 0.30, which resulted in a Reynolds number, based on mean aerodynamic chord, of 1.4 x 10(exp 6). Pressure data measured over the forebody and leading-edge extensions are compared to similar pressure data taken by a related NASA flight research program by using a specially instrumented F/A-18, the High-Alpha Research Vehicle (HARV). Preliminary guidelines for high-angle-of-attack gritting strategies are given.

Hall, Robert M.; Erickson, Gary E.; Fox, Charles H., Jr.; Banks, Daniel W.; Fisher, David F.

1998-01-01

314

Application of magnetic abrasive polishing to composite materials  

Microsoft Academic Search

Magnetic abrasive polishing (MAP) is an advanced machining process that can produce smoother surfaces in many material types.\\u000a The present study conducted an experimental assessment of MAP for a newly developed, non-ferrous and aluminum-based composite\\u000a material. A permanent magnet was installed under the workpiece to enhance its magnetic flux density, which had proved insufficient\\u000a for effective MAP. The success of

Tae-Wan Kim; Dae-Min Kang; Jae-Seob Kwak

2010-01-01

315

Effect of counterface roughness on abrasive wear of hydroxyapatite  

Microsoft Academic Search

The present study was undertaken to evaluate the effect of surface roughness of glass-infiltrated alumina on the abrasive wear of hydroxyapatite using a pin-on-disk tribometer. Hydroxyapatite was used as a model material to simulate tooth enamel. The wear tests were conducted in distilled water at room temperature using a constant sliding speed and three loads to model the normal occlusal

Mitjan Kalin; Said Jahanmir; Lewis K. Ives

2002-01-01

316

Wear behavior of materials in magnetically assisted abrasive flow machining  

Microsoft Academic Search

The finish machining of precision components constitutes one of the most challenging and expensive stages in a manufacturing process. Abrasive flow machining (AFM) is a non-traditional machining technique, which is capable of providing excellent surface finish on difficult-to-approach regions on a wide range of components. Not much research work has hitherto been reported regarding process behavior and performance improvement of

Sehijpal Singh; H. S Shan; P Kumar

2002-01-01

317

Developing a Process Model for Abrasive Flow Machining  

Microsoft Academic Search

\\u000a Abrasive flow machining (AFM) is a unique machining method used to achieve high surface quality on inner, difficult-to-access\\u000a contours and on outside edges. Using AFM, it is possible to deburr complex shaped intersecting holes and to realize pre-defined\\u000a edge rounding on any brittle or hard material. Moreover it is easy to integrate into an automated manufacturing environment.\\u000a Reproducibility of results

E. Uhlmann; V. Mihotovic; H. Szulczynski; M. Kretzschmar

318

Abrasion of eroded root dentine brushed with different toothpastes  

Microsoft Academic Search

This study evaluated the surface roughness change and wear provided by different dentifrices on root dentine previously exposed to erosive challenges. According to a randomized complete block design, 150 slabs of bovine root dentine (6×3×2 mm) were ground flat and polished. In an area of 4×3 mm on the dentine surface, specimens were submitted to five erosive\\/abrasive events, each one composed by:

Márcio de Menezes; Cecilia Pedroso Turssi; Anderson Takeo Hara; Danielle Cristine Furtado Messias; Mônica Campos Serra

2004-01-01

319

Porcine Head Response to Blast  

PubMed Central

Recent studies have shown an increase in the frequency of traumatic brain injuries related to blast exposure. However, the mechanisms that cause blast neurotrauma are unknown. Blast neurotrauma research using computational models has been one method to elucidate that response of the brain in blast, and to identify possible mechanical correlates of injury. However, model validation against experimental data is required to ensure that the model output is representative of in vivo biomechanical response. This study exposes porcine subjects to primary blast overpressures generated using a compressed-gas shock tube. Shock tube blasts were directed to the unprotected head of each animal while the lungs and thorax were protected using ballistic protective vests similar to those employed in theater. The test conditions ranged from 110 to 740?kPa peak incident overpressure with scaled durations from 1.3 to 6.9?ms and correspond approximately with a 50% injury risk for brain bleeding and apnea in a ferret model scaled to porcine exposure. Instrumentation was placed on the porcine head to measure bulk acceleration, pressure at the surface of the head, and pressure inside the cranial cavity. Immediately after the blast, 5 of the 20 animals tested were apneic. Three subjects recovered without intervention within 30?s and the remaining two recovered within 8?min following respiratory assistance and administration of the respiratory stimulant doxapram. Gross examination of the brain revealed no indication of bleeding. Intracranial pressures ranged from 80 to 390?kPa as a result of the blast and were notably lower than the shock tube reflected pressures of 300–2830?kPa, indicating pressure attenuation by the skull up to a factor of 8.4. Peak head accelerations were measured from 385 to 3845 G’s and were well correlated with peak incident overpressure (R2?=?0.90). One SD corridors for the surface pressure, intracranial pressure (ICP), and head acceleration are presented to provide experimental data for computer model validation. PMID:22586417

Shridharani, Jay K.; Wood, Garrett W.; Panzer, Matthew B.; Capehart, Bruce P.; Nyein, Michelle K.; Radovitzky, Raul A.; Bass, Cameron R. 'Dale'

2012-01-01

320

Blast waves in rotating media.  

NASA Technical Reports Server (NTRS)

The model investigated involves a cylindrically symmetric blast wave generated by an infinitely long line explosion in a cold and homogeneous gas rotating rigidly in its self-gravitational field. It is found that within the context of rotation in a gravitational field a blast wave will not adopt the one-zone form familiar from similarity solutions but, rather, a two-zone form. The inner compression zone arises as a response to the presence of the restoring force, which drives a rarefaction wave into the outer compression zone.

Rossner, L. F.

1972-01-01

321

Abrasion of Candidate Spacesuit Fabrics by Simulated Lunar Dust  

NASA Technical Reports Server (NTRS)

A protocol has been developed that produced the type of lunar soil abrasion damage observed on Apollo spacesuits. This protocol was then applied to four materials (Kevlar(Registered TradeMark), Vectran(Registered TradeMark), Orthofabric, and Tyvek(Registered TradeMark)) that are candidates for advanced spacesuits. Three of the four new candidate fabrics (all but Vectran(Registered TradeMark)) were effective at keeping the dust from penetrating to layers beneath. In the cases of Kevlar(Registered TradeMark) and Orthofabric this was accomplished by the addition of a silicone layer. In the case of Tyvek , the paper structure was dense enough to block dust transport. The least abrasive damage was suffered by the Tyvek(Registered TradeMark). This was thought to be due in large part to its non-woven paper structure. The woven structures were all abraded where the top of the weave was struck by the abrasive. Of these, the Orthofabric suffered the least wear, with both Vectran(Registered TradeMark) and Kevlar(Registered TradeMark) suffering considerably more extensive filament breakage.

Gaier, James R.; Meador, Mary Ann; Rogers, Kerry J.; Sheehy, Brennan H.

2009-01-01

322

Development of underwater cutting system by abrasive water-jet  

NASA Astrophysics Data System (ADS)

The technology to cut objects in the ocean's depths with abrasive water jets was examined for possible application in view of the greater water depths and sophistication involved in work on the ocean floor today. A test model was developed to study this technology's safety and practicability. The test model was designed for use at great water depths and has functions and a configuration that are unlike equipment used on land. A continuous, stable supply of abrasive is a distinctive design feature. In land applications, there had been problems with plugged tubes and an uneven supply. For this reason, the abrasive was converted to slurry form, and a continuous pressurized tube pump system was adopted for supply to the nozzle head. Also, a hydraulic motor that does not employ oil or electric power was used to provide an underwater drive that is environment-friendly. The report outlines the technology's general design concept including its distinctive functions and its configuration for use at great depths, and the report provides great detail on the equipment.

Demura, Kenji; Yamaguchi, Hitoshi

1993-09-01

323

Characterization of Effective Parameters in Abrasive Waterjet Rock Cutting  

NASA Astrophysics Data System (ADS)

The rock cutting performance of an abrasive waterjet is affected by various parameters. In this study, rock cutting tests are conducted with different energy (i.e., water pressure, traverse speed, and abrasive feed rate), geometry (i.e., standoff distance), and material parameters [i.e., uniaxial compressive strength (UCS)]. In particular, experimental tests are carried out at a long standoff distance (up to 60 cm) to consider field application. The effective parameters of the rock cutting process are identified based on the relationships between the cutting performance indices (depth, width, and volume) and parameters. In addition, the cutting efficiency is analyzed with effective parameters as well as different pump types and the number of cutting passes considering the concept of kinetic jet energy. Efficiency analysis reveals that the cutting depth efficiency tends to increase with an increase in the water pressure and traverse speed and with a decrease in the standoff distance and UCS. Cutting volume efficiency strongly depends on standoff distance. High efficiency of cutting volume is obtained at a long standoff distance regardless of the pump type. The efficiency analysis provides a realistic way to optimize parameters for abrasive waterjet rock excavation.

Oh, Tae-Min; Cho, Gye-Chun

2014-03-01

324

Abrasion of eroded root dentine brushed with different toothpastes.  

PubMed

This study evaluated the surface roughness change and wear provided by different dentifrices on root dentine previously exposed to erosive challenges. According to a randomized complete block design, 150 slabs of bovine root dentine (6 x 3 x 2 mm) were ground flat and polished. In an area of 4 x 3 mm on the dentine surface, specimens were submitted to five erosive/abrasive events, each one composed by: exposure to Sprite Diet or distilled water for 5 min, then to a remineralizing solution for 1 min, and simulation of 5,000 brushing strokes. Four dentifrices--regular (RE), baking soda (BS), whitening (WT) and tartar control (TC)--and distilled water (CO), used as control, were compared. Final texture and the wear depth were evaluated using a profilometer. ANOVA did not show significant interaction, indicating that the effect of dentifrices on both surface roughness change and wear did not depend on whether or not the dentine was eroded ( p>0.05). There was no difference between abrasion of eroded and sound dentine. The Tukey's test revealed that WT, BS and TC provided the highest increase in surface roughness differing from RE and CO. TC yielded the deepest wear of root dentine, whereas RE and CO, the shallowest. No significant difference in wear among BS, TC and WT were observed. Within the limitations of this study, the data showed that abrasion of both eroded and sound root dentine was dependent on the dentifrice used. PMID:15146320

De Menezes, Márcio; Turssi, Cecilia Pedroso; Hara, Anderson Takeo; Messias, Danielle Cristine Furtado; Serra, Mônica Campos

2004-09-01

325

Analysis of fluid flow and heat transfer in a rib grit roughened surface solar air heater using CFD  

SciTech Connect

This paper presents the study of fluid flow and heat transfer in a solar air heater by using Computational Fluid Dynamics (CFD) which reduces time and cost. Lower side of collector plate is made rough with metal ribs of circular, square and triangular cross-section, having 60 inclinations to the air flow. The grit rib elements are fixed on the surface in staggered manner to form defined grid. The system and operating parameters studied are: e/D{sub h} = 0.044, p/e = 17.5 and l/s = 1.72, for the Reynolds number range 3600-17,000. To validate CFD results, experimental investigations were carried out in the laboratory. It is found that experimental and CFD analysis results give the good agreement. The optimization of rib geometry and its angle of attack is also done. The square cross-section ribs with 58 angle of attack give maximum heat transfer. The percentage enhancement in the heat transfer for square plate over smooth surface is 30%. (author)

Karmare, S.V. [Department of Mechanical Engineering, Government College Engineering, Karad 415 124, Maharashtra (India); Shivaji University, Kolhapur, Maharashtra (India); Tikekar, A.N. [Department of Mechanical Engineering, Walchand College of Engineering, Sangli (India); Shivaji University, Kolhapur, Maharashtra (India)

2010-03-15

326

Drill and Blast Tunneling Practices  

Microsoft Academic Search

High-performance drill and blast methods for tunnel construction require that each of the individual working elements that constitute the construction process are optimized and considered as a system of sequential and parallel activities. The advantage of integrating the logistic backup systems facilitates an increase in performance. To achieve increased production, it is necessary to improve the drilling, explosive loading, temporary

Gerhard Girmscheid; Cliff Schexnayder

2002-01-01

327

The Next Generation BLAST Experiment  

NASA Astrophysics Data System (ADS)

The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) was a suborbital experiment designed to map magnetic fields in order to study their role in star formation processes. BLASTPol made detailed polarization maps of a number of molecular clouds during its successful flights from Antarctica in 2010 and 2012. We present the next-generation BLASTPol instrument (BLAST-TNG) that will build off the success of the previous experiment and continue its role as a unique instrument and a test bed for new technologies. With a 16-fold increase in mapping speed, BLAST-TNG will make larger and deeper maps. Major improvements include a 2.5-m carbon fiber mirror that is 40% wider than the BLASTPol mirror and 3000 polarization sensitive detectors. BLAST-TNG will observe in three bands at 250, 350, and 500 ?m. The telescope will serve as a pathfinder project for microwave kinetic inductance detector (MKID) technology, as applied to feedhorn-coupled submillimeter detector arrays. The liquid helium cooled cryostat will have a 28-day hold time and will utilize a closed-cycle 3He refrigerator to cool the detector arrays to 270 mK. This will enable a detailed mapping of more targets with higher polarization resolution than any other submillimeter experiment to date. BLAST-TNG will also be the first balloon-borne telescope to offer shared risk observing time to the community. This paper outlines the motivation for the project and the instrumental design.

Galitzki, Nicholas; Ade, Peter A. R.; Angilè, Francesco E.; Ashton, Peter; Beall, James A.; Becker, Dan; Bradford, Kristi J.; Che, George; Cho, Hsiao-Mei; Devlin, Mark J.; Dober, Bradley J.; Fissel, Laura M.; Fukui, Yasuo; Gao, Jiansong; Groppi, Christopher E.; Hillbrand, Seth; Hilton, Gene C.; Hubmayr, Johannes; Irwin, Kent D.; Klein, Jeffrey; van Lanen, Jeff; Li, Dale; Li, Zhi-Yun; Lourie, Nathan P.; Mani, Hamdi; Martin, Peter G.; Mauskopf, Philip; Nakamura, Fumitaka; Novak, Giles; Pappas, David P.; Pascale, Enzo; Pisano, Giampaolo; Santos, Fabio P.; Savini, Giorgio; Scott, Douglas; Stanchfield, Sara; Tucker, Carole; Ullom, Joel N.; Underhill, Matthew; Vissers, Michael R.; Ward-Thompson, Derek

328

Effect of coupling agent on abrasive wear behaviour of chopped jute fibre-reinforced polypropylene composites  

Microsoft Academic Search

In this paper, studies have been conducted to investigate the abrasive wear behaviour of jute fibre-reinforced polypropylene composites. Effect of addition of maleic anhydride-grafted polypropylene (MA-g-PP)-coupling agent by two different approach, sliding distance and load on abrasive wear performance of jute fibre–PP composites has been determined by using a SUGA abrasion tester. Use of coupling agent gives better wear resistance

Navin Chand; U. K. Dwivedi

2006-01-01

329

Evaluation of ASTM G65 abrasive —Spanning 13 years of sand  

Microsoft Academic Search

Standardized testing requires consistency of all testing parameters including consumables. One of the more common American Society for Testing and Materials (ASTM) tests to evaluate abrasive wear resistance is the ASTM G65-04 Standard Test Method for Measuring Abrasion Using the Dry Sand\\/Rubber Wheel Apparatus. The specified abrasive is nominally 100% silica (SiO2), sieved to 50\\/70 mesh. To quantify the consistency

A. Doering; D. Danks; S. Mahmoud; J. Scott

2011-01-01

330

Micro machining of an STS 304 bar by magnetic abrasive finishing  

Microsoft Academic Search

A magnetic abrasive finishing process is a method of non-traditional precision machining in which the finishing process is\\u000a completed using magnetic force and magnetic abrasives. In this research, a STS 304 cylindrical workpiece was finished using\\u000a a magnetic abrasive finishing process at 30,000 rpm, and the roughness, roundness, and changes in the micro-diameter were\\u000a investigated. The study showed that it

Ik-Tae Im; Sang Don Mun; Seong Mo Oh

2009-01-01

331

Study of magnetic abrasive finishing in free-form surface operations using the Taguchi method  

Microsoft Academic Search

This study employed magnetic abrasive finishing (MAF) to conduct free-form surface abrasion of stainless SUS304 material operations.\\u000a The operations were demonstrated using a permanent magnetic finishing mechanism installed at the CNC machining center. The\\u000a operations were performed using the Taguchi experimental design, considering the effects of magnetic field, spindle revolution,\\u000a feed rate, working gap, abrasive, and lubricant. Furthermore, the experimental

Ching-Tien Lin; Lieh-Dai Yang; Han-Ming Chow

2007-01-01

332

Abrasive wear behavior of NiAl and NiAl–TiB 2 composites  

Microsoft Academic Search

Abrasive wear of NiAl and NiAl with 10, 20, and 40 vol.% TiB2 has been investigated using particles of different types and sizes. The addition of TiB2 as a particulate reinforcement to NiAl increases the hardness of the composite with respect to NiAl, and reduces the wear rate at all volume fractions on garnet and Al2O3 abrasives. Abrasion on SiC

Jeffrey A. Hawk; David E. Alman

1999-01-01

333

Morphology and integrity of surfaces finished by centrifugal force assisted abrasive flow machining  

Microsoft Academic Search

Centrifugal force assisted abrasive flow machining (CFAAFM) process has recently been tried as a hybrid machining process\\u000a with the aim towards performance improvement of assisted abrasive flow machining (AFM) process by applying centrifugal force\\u000a on the abrasive-laden media with a rotating centrifugal force generating (CFG) rod introduced in the workpiece passage. In\\u000a the CFAAFM process, the surfaces are generated by

R. S. Walia; H. S. Shan; P. Kumar

2008-01-01

334

Analytical method for softness abrasive flow field based on discrete phase model  

Microsoft Academic Search

Aiming at the problem of difficult contact finishing for mini structural surface in course of mould manufacturing, a new no-tool\\u000a precision machining method based on soft abrasive flow machining (SAFM) was proposed. It allocated restrained component near\\u000a surface machined, constituted restrained abrasive flow passage, and made the surface become a segment of passage wall. It\\u000a could control turbulence abrasive flow

ShiMing Ji; FengQing Xiao; DaPeng Tan

2010-01-01

335

Mapping the micro-abrasion resistance of WC\\/Co based coatings in aqueous conditions  

Microsoft Academic Search

Significant progress has been made in recent years on the study of micro-abrasion mechanisms of materials. Regimes of micro-abrasion have been proposed which identify whether the wear occurs either by a two-body or a three-body mechanism. Micro-abrasion maps have been constructed showing the variation in wear regime, as a function of applied load and sliding distance. There has, however, been

M. M. Stack; M. T. Mathew

2004-01-01

336

The abrasive wear behaviour of Al-SiCp composites for automotive parts  

Microsoft Academic Search

The present work reports on the continuous abrasives wear behaviour of Al-SiCp composites with 5 to 30 wt. % of SiC particulates. A pin-on-drum wear-testing machine was designed and fabricated to study the effects of wt. % of SiCp, load, relative velocity and abrasive particle characteristics on abrasive wear behaviour of Al-SiCp composite with 5 to 30 wt. % of

G. Hemath Kumar; B. R. Ramesh Bapu; R. Sagar; H. Mohit

2010-01-01

337

GENERAL VIEW OF TURBOBLOWER BUILDING (LEFT), BLAST FURNACE (CENTER), AND ...  

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

GENERAL VIEW OF TURBO-BLOWER BUILDING (LEFT), BLAST FURNACE (CENTER), AND HOT BLAST STOVES (RIGHT). - Republic Iron & Steel Company, Youngstown Works, Haselton Blast Furnaces, West of Center Street Viaduct, along Mahoning River, Youngstown, Mahoning County, OH

338

Looking east at blast furnace no. 5 between the hot ...  

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

Looking east at blast furnace no. 5 between the hot blast stoves (left) and the dustcatcher (right). - U.S. Steel Edgar Thomson Works, Blast Furnace Plant, Along Monongahela River, Braddock, Allegheny County, PA

339

9. LOOKING NORTH AT TRESTLE, HOIST HOUSE No. 1, BLAST ...  

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

9. LOOKING NORTH AT TRESTLE, HOIST HOUSE No. 1, BLAST FURNACE No. 1, AND HOT BLAST STOVES. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

340

Looking southeast at blast furnaces no. 5 and no. 6 ...  

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

Looking southeast at blast furnaces no. 5 and no. 6 with blast furnace trestle and Gondola Railroad cars in foreground. - U.S. Steel Edgar Thomson Works, Blast Furnace Plant, Along Monongahela River, Braddock, Allegheny County, PA

341

INTERIOR VIEW LOOKING WEST, CAST HOUSE OF BLAST FURNACE NO. ...  

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

INTERIOR VIEW LOOKING WEST, CAST HOUSE OF BLAST FURNACE NO. 1 AND BLAST FURNACE NO. 2. - Pittsburgh Steel Company, Monessen Works, Blast Furnace No. 1 & No. 2, Donner Avenue, Monessen, Westmoreland County, PA

342

Looking southwest at blast furnaces no. 5 and no. 6 ...  

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

Looking southwest at blast furnaces no. 5 and no. 6 with blast furnace trestle and Gondola Railroad cars in foreground. - U.S. Steel Edgar Thomson Works, Blast Furnace Plant, Along Monongahela River, Braddock, Allegheny County, PA

343

30 CFR 57.6306 - Loading, blasting, and security.  

Code of Federal Regulations, 2012 CFR

...device, all persons shall leave the blast area except persons in a blasting shelter or other location that protects them from concussion (shock wave), flying material, and gases. (f) Before firing a blast— (1) Ample warning shall be given to...

2012-07-01

344

30 CFR 56.6306 - Loading, blasting, and security.  

Code of Federal Regulations, 2013 CFR

...device, all persons shall leave the blast area except persons in a blasting shelter or other location that protects them from concussion (shock wave), flying material, and gases. (f) Before firing a blast— (1) Ample warning shall be given to...

2013-07-01

345

30 CFR 56.6306 - Loading, blasting, and security.  

Code of Federal Regulations, 2012 CFR

...device, all persons shall leave the blast area except persons in a blasting shelter or other location that protects them from concussion (shock wave), flying material, and gases. (f) Before firing a blast— (1) Ample warning shall be given to...

2012-07-01

346

30 CFR 57.6306 - Loading, blasting, and security.  

Code of Federal Regulations, 2013 CFR

...device, all persons shall leave the blast area except persons in a blasting shelter or other location that protects them from concussion (shock wave), flying material, and gases. (f) Before firing a blast— (1) Ample warning shall be given to...

2013-07-01

347

30 CFR 77.1910 - Explosives and blasting; general.  

...2014-07-01 2014-07-01 false Explosives and blasting; general. 77.1910...Slope and Shaft Sinking § 77.1910 Explosives and blasting; general. (a...charging and blasting. (b) All explosive materials, detonators, and any...

2014-07-01

348

30 CFR 77.1910 - Explosives and blasting; general.  

Code of Federal Regulations, 2010 CFR

...circuits shall be disconnected or removed from the blasting area before charging and blasting. (b) All explosive materials, detonators, and any other related blasting material employed in the development of any slope or shaft shall be stored,...

2010-07-01

349

30 CFR 77.1304 - Blasting agents; special provisions.  

...Blasting agents; special provisions. (a) Sensitized ammonium nitrate blasting agents, and the components thereof prior to mixing...Circular 8179, “Safety Recommendations for Sensitized Ammonium Nitrate Blasting Agents,” or subsequent revisions....

2014-07-01

350

30 CFR 77.1304 - Blasting agents; special provisions.  

Code of Federal Regulations, 2013 CFR

...Blasting agents; special provisions. (a) Sensitized ammonium nitrate blasting agents, and the components thereof prior to mixing...Circular 8179, “Safety Recommendations for Sensitized Ammonium Nitrate Blasting Agents,” or subsequent revisions....

2013-07-01

351

30 CFR 75.1310 - Explosives and blasting equipment.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Explosives and blasting equipment. 75.1310 Section...SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1310 Explosives and blasting equipment. (a) Only...

2013-07-01

352

30 CFR 75.1310 - Explosives and blasting equipment.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Explosives and blasting equipment. 75.1310 Section...SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1310 Explosives and blasting equipment. (a) Only...

2012-07-01

353

30 CFR 75.1310 - Explosives and blasting equipment.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Explosives and blasting equipment. 75.1310 Section...SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1310 Explosives and blasting equipment. (a) Only...

2011-07-01

354

30 CFR 75.1310 - Explosives and blasting equipment.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Explosives and blasting equipment. 75.1310 Section...SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1310 Explosives and blasting equipment. (a) Only...

2010-07-01

355

30 CFR 75.1310 - Explosives and blasting equipment.  

...2014-07-01 2014-07-01 false Explosives and blasting equipment. 75.1310 Section...SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1310 Explosives and blasting equipment. (a) Only...

2014-07-01

356

27 CFR 555.220 - Table of separation distances of ammonium nitrate and blasting agents from explosives or blasting...  

...Table of separation distances of ammonium nitrate and blasting agents from explosives or...Table of separation distances of ammonium nitrate and blasting agents from explosives or...donor when barricaded (ft.) Ammonium nitrate Blasting agent Minimum thickness...

2014-04-01

357

27 CFR 555.220 - Table of separation distances of ammonium nitrate and blasting agents from explosives or blasting...  

Code of Federal Regulations, 2012 CFR

...Table of separation distances of ammonium nitrate and blasting agents from explosives or...Table of separation distances of ammonium nitrate and blasting agents from explosives or...donor when barricaded (ft.) Ammonium nitrate Blasting agent Minimum thickness...

2012-04-01

358

27 CFR 555.220 - Table of separation distances of ammonium nitrate and blasting agents from explosives or blasting...  

Code of Federal Regulations, 2013 CFR

...Table of separation distances of ammonium nitrate and blasting agents from explosives or...Table of separation distances of ammonium nitrate and blasting agents from explosives or...donor when barricaded (ft.) Ammonium nitrate Blasting agent Minimum thickness...

2013-04-01

359

27 CFR 555.220 - Table of separation distances of ammonium nitrate and blasting agents from explosives or blasting...  

Code of Federal Regulations, 2011 CFR

...Table of separation distances of ammonium nitrate and blasting agents from explosives or...Table of separation distances of ammonium nitrate and blasting agents from explosives or...donor when barricaded (ft.) Ammonium nitrate Blasting agent Minimum thickness...

2011-04-01

360

27 CFR 555.220 - Table of separation distances of ammonium nitrate and blasting agents from explosives or blasting...  

Code of Federal Regulations, 2010 CFR

...Table of separation distances of ammonium nitrate and blasting agents from explosives or...Table of separation distances of ammonium nitrate and blasting agents from explosives or...donor when barricaded (ft.) Ammonium nitrate Blasting agent Minimum thickness...

2010-04-01

361

Research on the precision processing method for softness abrasive two-phase flow based on LSM  

Microsoft Academic Search

According to the precision machining problem of the structural surface mould manufacturing process, a method for soft grits two-phase flow precision processing on the level set method (LSM) is proposed. Based on the topological structure transformation of LSM, the mechanics model of liquid-liquid two phase flow in mould structuring surface precision machining was established. And the interface parameters of the

Shiming Ji; Xiaoxing Weng; Dapeng Tan

2010-01-01

362

Procedure for calculating drilling and blasting parameters and experience of blasting in constrained material  

Microsoft Academic Search

Tight-face blasting is a production method which provides an improvement in drilling and blasting (DAB) indices and it involves the fact that the blasted volume over the breaking front is 'overloaded' by constrained material. The constraining material used is previously broken rock mass which has an acoustic stiffness several times less than the material being broken and a capacity to

N. I. Semenyakin; V. V. Arshavskii; A. S. Bykovtsev; V. N. Oparin; V. B. Vil'chinskii

1993-01-01

363

Photographs of Blast Effects on Structures  

NSDL National Science Digital Library

This photograph collection shows a wood-frame house located 1,100 meters from ground zero, exposed to a nuclear blast at the Nevada Test Site. The test was Upshot-Knothole Annie, a 16 Kt tower shot, on March 17, 1953. Exposure to thermal radiation was 25 cal/cm2, about one-quarter of that experienced at ground zero in Hiroshima. The blast over pressure was 5 psi, and the blast wave created surface winds of 160 mph.

Griffith, Christopher

364

BLAST FURNACE GRANULAR COAL INJECTION SYSTEM  

Microsoft Academic Search

Bethlehem Steel Corporation (BSC) requested financial assistance from the Department of Energy (DOE), for the design, construction and operation of a 2,800-ton-per-day blast furnace granulated coal injection (BFGCI) system for two existing iron-making blast furnaces. The blast furnaces are located at BSC's facilities in Burns Harbor, Indiana. The demonstration project proposal was selected by the DOE and awarded to Bethlehem

1999-01-01

365

Heat sealable, flame and abrasion resistant coated fabric  

NASA Technical Reports Server (NTRS)

Flame retardant, abrasion resistant elastomeric compositions are disclosed which are comprised of thermoplastic polyurethane polymer and flame retarding amounts of a filler selected from decabromodiphenyloxide and antimony oxide in a 3:1 weight ratio, and decabromodiphenyloxide, antimony oxide, and ammonium polyphosphate in a 3:1:3 weight ratio respectively. Heat sealable coated fabrics employing such elastomeric compositions as coating film are produced by dissolving the elastomeric composition to form a solution, casting the solution onto a release paper and drying it to form an elastomeric film. The film is then bonded to a woven, knitted, or felted fabric.

Tschirch, R. P.; Sidman, K. R. (inventors)

1983-01-01

366

Solution of the Roth-Marques-Durian Rotational Abrasion Model  

E-print Network

We solve the rotational abrasion model of Roth, Marques and Durian (arXiv:1009.3492), a one-dimensional quasilinear partial differential equation resembling the inviscid Burgers equation with the unusual feature of a step function factor as a coefficient. The complexity of the solution is primarily in keeping track of the cases in the piecewise function that results from certain amputation and interpolation processes, so we also extract from it a model of an evolving planar tree graph that tracks the evolution of the coarse features of the contour.

Bryan Gin-ge Chen

2010-12-10

367

Solution of the Roth-Marques-Durian rotational abrasion model.  

PubMed

We solve the rotational abrasion model of Roth, Marques, and Durian [Phys. Rev. E 83, 031303 (2011)], a one-dimensional quasilinear partial differential equation resembling the inviscid Burgers equation with the unusual feature of a step function factor as a coefficient. The complexity of the solution is primarily in keeping track of the cases in the piecewise function that results from certain amputation and interpolation processes, so we also extract from it a model of an evolving planar tree graph that tracks the evolution of the coarse features of the contour. PMID:21517491

Chen, Bryan Gin-ge

2011-03-01

368

Solution of the Roth-Marques-Durian rotational abrasion model  

NASA Astrophysics Data System (ADS)

We solve the rotational abrasion model of Roth, Marques, and Durian [Phys. Rev. EPRLTAO1539-375510.1103/PhysRevE.83.031303 83, 031303 (2011)], a one-dimensional quasilinear partial differential equation resembling the inviscid Burgers equation with the unusual feature of a step function factor as a coefficient. The complexity of the solution is primarily in keeping track of the cases in the piecewise function that results from certain amputation and interpolation processes, so we also extract from it a model of an evolving planar tree graph that tracks the evolution of the coarse features of the contour.

Chen, Bryan Gin-Ge

2011-03-01

369

ScalaBLAST 2.0: Rapid and robust BLAST calculations on multiprocessor systems  

SciTech Connect

BLAST remains one of the most widely used tools in computational biology. The rate at which new sequence data is available continues to grow exponentially, driving the emergence of new fields of biological research. At the same time multicore systems and conventional clusters are more accessible. ScalaBLAST has been designed to run on conventional multiprocessor systems with an eye to extreme parallelism, enabling parallel BLAST calculations using over 16,000 processing cores with a portable, robust, fault-resilient design. ScalaBLAST 2.0 source code can be freely downloaded from http://omics.pnl.gov/software/ScalaBLAST.php.

Oehmen, Christopher S.; Baxter, Douglas J.

2013-03-15

370

Attrition and abrasion models for oil shale process modeling  

SciTech Connect

As oil shale is processed, fine particles, much smaller than the original shale are created. This process is called attrition or more accurately abrasion. In this paper, models of abrasion are presented for oil shale being processed in several unit operations. Two of these unit operations, a fluidized bed and a lift pipe are used in the Lawrence Livermore National Laboratory Hot-Recycle-Solid (HRS) process being developed for the above ground processing of oil shale. In two reports, studies were conducted on the attrition of oil shale in unit operations which are used in the HRS process. Carley reported results for attrition in a lift pipe for oil shale which had been pre-processed either by retorting or by retorting then burning. The second paper, by Taylor and Beavers, reported results for a fluidized bed processing of oil shale. Taylor and Beavers studied raw, retorted, and shale which had been retorted and then burned. In this paper, empirical models are derived, from the experimental studies conducted on oil shale for the process occurring in the HRS process. The derived models are presented along with comparisons with experimental results.

Aldis, D.F.

1991-10-25

371

Air abrasion experiments in U-Pb dating of zircon  

USGS Publications Warehouse

Air abrasion of zircon grains can remove metamict material that has lost radiogenic Pb and zircon overgrowths that were added during younger events and thereby improve the precision of the age measurements and permit closer estimates of the original age. Age discordance that resulted from a single disturbance of the U-Pb isotopic decay systems, as had been demonstrated by T.E. Krogh, can be considerably reduced, and, under favorable conditions, the ages brought into concordancy. Two or more events complicate the U-Pb systematics, but a series of abrasion experiments can be helpful in deciphering the geologic history and in arriving at a useful interpretation of the probable times of origin and disturbances. In east-central Minnesota, U.S.A., Penokean tonalite gneiss is dated at 1869 ?? 5 Ma, and sheared granite gneiss is shown to have been a high-level granite intrusion at 1982 ?? 5 Ma in the McGrath Gneiss precursor. Tonalite gneiss and a mafic granodiorite in the Rainy Lake area, Ontario, Canada, are dated at 2736 ?? 16 and 2682 ?? 4 Ma, respectively. The tonalitic phase of the Morton Gneiss, southwestern Minnesota, is dated at 3662 ?? 42 Ma. ?? 1986.

Goldich, S.S.; Fischer, L.B.

1986-01-01

372

Abrasion resistant coating and method of making the same  

DOEpatents

An abrasion resistant coating is created by adding a ductile phase to a brittle matrix phase during spray coating where an Al--Cu--Fe quasicrystalline phase (brittle matrix) and an FeAl intermetallic (ductile phase) are combined. This composite coating produces a coating mostly of quasicrystal phase and an inter-splat layer of the FeAl phase to help reduce porosity and cracking within the coating. Coatings are prepared by plasma spraying unblended and blended quasicrystal and intermetallic powders. The blended powders contain 1, 5, 10 and 20 volume percent of the intermetallic powders. The unblended powders are either 100 volume percent quasicrystalline or 100 volume percent intermetallic; these unblended powders were studied for comparison to the others. Sufficient ductile phase should be added to the brittle matrix to transform abrasive wear mode from brittle fracture to plastic deformation, while at the same time the hardness of the composite should not be reduced below that of the original brittle phase material.

Sordelet, Daniel J. (Ames, IA); Besser, Matthew F. (Urbandale, IA)

2001-06-05

373

Cutting meat with bone using an ultrahigh pressure abrasive waterjet.  

PubMed

An experimental study of abrasive waterjet (AWJ) cutting of beef, pork and lamb meat with and without bone is presented. Salt particles were used as the abrasives. It has been found that an AWJ could significantly increase the depth of cut with much improved cut quality in cutting pure meat as compared to plain (or pure) waterjet cutting, while a plain waterjet was incapable of cutting bone satisfactorily. The study shows that AWJ cutting produced a very narrow kerf of less than 1mm and hence resulted in mush less meat loss than the traditional cutting processes, and meat can be cut at room temperature to eliminate the freezing or chilling costs. It is shown that a traverses speed of 20mm/s can be used to cut through 44mm thick beef rib bones with good cut quality. When slicing pure meat of 150mm thickness, the traverse speed of 66.67mm/s can yield very good cut quality. It is suggested that AWJ cutting is a viable technology for meat cutting. Plausible trends for the depth of cut, cutting rate and cut quality with respect to the process variables are discussed. Recommendations are finally made for the selection of the most appropriate process parameters for cutting meat of a given thickness. PMID:20416572

Wang, J; Shanmugam, D K

2009-04-01

374

Abrasive waterjet machining of fiber reinforced composites: A review  

NASA Astrophysics Data System (ADS)

Machining of fiber reinforced polymer (FRP) composites is a major secondary manufacturing activity in the aircraft and automotive industries. Traditional machining of these composites is difficult due to the high abrasiveness nature of their reinforcing constituents. Almost all the traditional machining processes involve in the dissipation of heat into the workpiece which can be resulted in damage to workpiece and rapid wear of the cutting tool. This serious issue has been overcome by water jetting technologies. Abrasive waterjet machining (AWJM) is a nontraditional method and one of the best options for machining FRPs. This paper presents a review of the ongoing research and development in AWJM of FRPs, with a critical review of the physics of the machining process, surface characterization, modeling and the newer application to the basic research. Variable cutting parameters, limitations and safety aspects of AWJM and the noise related issues due to high flow rate of water jet will be addressed. Further challenges and scope of the future development in AWJM are also presented in detail.

Kalla, D. K.; Dhanasekaran, P. S.; Zhang, B.; Asmatulu, R.

2012-04-01

375

Prediction Of Abrasive And Diffusive Tool Wear Mechanisms In Machining  

NASA Astrophysics Data System (ADS)

Tool wear prediction is regarded as very important task in order to maximize tool performance, minimize cutting costs and improve the quality of workpiece in cutting. In this research work, an experimental campaign was carried out at the varying of cutting conditions with the aim to measure both crater and flank tool wear, during machining of an AISI 1045 with an uncoated carbide tool P40. Parallel a FEM-based analysis was developed in order to study the tool wear mechanisms, taking also into account the influence of the cutting conditions and the temperature reached on the tool surfaces. The results show that, when the temperature of the tool rake surface is lower than the activation temperature of the diffusive phenomenon, the wear rate can be estimated applying an abrasive model. In contrast, in the tool area where the temperature is higher than the diffusive activation temperature, the wear rate can be evaluated applying a diffusive model. Finally, for a temperature ranges within the above cited values an adopted abrasive-diffusive wear model furnished the possibility to correctly evaluate the tool wear phenomena.

Rizzuti, S.; Umbrello, D.

2011-01-01

376

Sliding-gate valve for use with abrasive materials  

DOEpatents

The invention is a flow and pressure-sealing valve for use with abrasive solids. The valve embodies special features which provide for long, reliable operating lifetimes in solids-handling service. The valve includes upper and lower transversely slidable gates, contained in separate chambers. The upper gate provides a solids-flow control function, whereas the lower gate provides a pressure-sealing function. The lower gate is supported by means for (a) lifting that gate into sealing engagement with its seat when the gate is in its open and closed positions and (b) lowering the gate out of contact with its seat to permit abrasion-free transit of the gate between its open and closed positions. When closed, the upper gate isolates the lower gate from the solids. Because of this shielding action, the sealing surface of the lower gate is not exposed to solids during transit or when it is being lifted or lowered. The chamber containing the lower gate normally is pressurized slightly, and a sweep gas is directed inwardly across the lower-gate sealing surface during the vertical translation of the gate.

Ayers, Jr., William J. (Morgantown, WV); Carter, Charles R. (Fairmont, WV); Griffith, Richard A. (Morgantown, WV); Loomis, Richard B. (Bruceton Mills, WV); Notestein, John E. (Morgantown, WV)

1985-01-01

377

The Next Generation BLAST Experiment  

E-print Network

The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol) was a suborbital experiment designed to map magnetic fields in order to study their role in star formation processes. BLASTPol made detailed polarization maps of a number of molecular clouds during its successful flights from Antarctica in 2010 and 2012. We present the next-generation BLASTPol instrument (BLAST-TNG) that will build off the success of the previous experiment and continue its role as a unique instrument and a test bed for new technologies. With a 16-fold increase in mapping speed, BLAST-TNG will make larger and deeper maps. Major improvements include a 2.5 m carbon fiber mirror that is 40% wider than the BLASTPol mirror and ~3000 polarization sensitive detectors. BLAST-TNG will observe in three bands at 250, 350, and 500 microns. The telescope will serve as a pathfinder project for microwave kinetic inductance detector (MKID) technology, as applied to feedhorn coupled submillimeter detector arrays. The liquid he...

Galitzki, Nicholas; Angilè, Francesco E; Ashton, Peter; Beall, James A; Becker, Dan; Bradford, Kristi J; Che, George; Cho, Hsiao-Mei; Devlin, Mark J; Dober, Bradley J; Fissel, Laura M; Fukui, Yasuo; Gao, Jiansong; Groppi, Christopher E; Hillbrand, Seth; Hilton, Gene C; Hubmayr, Johannes; Irwin, Kent D; Klein, Jeffrey; Van Lanen, Jeff; Li, Dale; Li, Zhi-Yun; Lourie, Nathan P; Mani, Hamdi; Martin, Peter G; Mauskopf, Philip; Nakamura, Fumitaka; Novak, Giles; Pappas, David P; Pascale, Enzo; Pisano, Giampaolo; Santos, Fabio P; Savini, Giorgio; Scott, Douglas; Stanchfield, Sara; Tucker, Carole; Ullom, Joel N; Underhill, Matthew; Vissers, Michael R; Ward-Thompson, Derek

2014-01-01

378

Process Monitoring Evaluation and Implementation for the Wood Abrasive Machining Process  

PubMed Central

Wood processing industries have continuously developed and improved technologies and processes to transform wood to obtain better final product quality and thus increase profits. Abrasive machining is one of the most important of these processes and therefore merits special attention and study. The objective of this work was to evaluate and demonstrate a process monitoring system for use in the abrasive machining of wood and wood based products. The system developed increases the life of the belt by detecting (using process monitoring sensors) and removing (by cleaning) the abrasive loading during the machining process. This study focused on abrasive belt machining processes and included substantial background work, which provided a solid base for understanding the behavior of the abrasive, and the different ways that the abrasive machining process can be monitored. In addition, the background research showed that abrasive belts can effectively be cleaned by the appropriate cleaning technique. The process monitoring system developed included acoustic emission sensors which tended to be sensitive to belt wear, as well as platen vibration, but not loading, and optical sensors which were sensitive to abrasive loading. PMID:22163477

Saloni, Daniel E.; Lemaster, Richard L.; Jackson, Steven D.

2010-01-01

379

Corneal abrasion after the wake-up test in spinal surgery  

Microsoft Academic Search

To the editor: Ophthalmic complications such as visual loss, eye injuries, and corneal abrasion have been reported to occur, although rarely, during anesthesia. To prevent the eye from drying during general anesthesia, eye tape or ophthalmic ointment often is applied to the eyes. We encountered corneal abrasion that presumably occurred after the wake-up test for spine surgery in a patient

Fumi Yanagidate; Shuji Dohi

2003-01-01

380

In situ observation of the behavior of abrasives in magnetic fluid grinding  

NASA Astrophysics Data System (ADS)

In order to understand the effect of a magnetic field on the polishing properties, the behavior of abrasives in a magnetic fluid between two mating surfaces was observed in situ during magnetic fluid grinding. It was shown that the number of abrasives on the finishing surface could be controlled by the magnetic field during finishing by the magnetic field.

Umehara, N.; Hayashi, T.; Kato, K.

1995-08-01

381

Abrasive Wear Resistance of Tool Steels Evaluated by the Pin-on-Disc Testing  

Microsoft Academic Search

Present work examines tool steels abrasion wear resistance and the abrasion mechanisms which are one main contributor to failure of tooling in metal forming industry. Tooling used in cutting and metal forming processes without lubrication fails due to this type of wear. In the workshop and engineering practice, it is common to relate wear resistance as function of material hardness

José Divo Bressan; Roberto Alexandre Schopf

2011-01-01

382

Cutting Tools, Files and Abrasives. Pre-Apprenticeship Phase 1 Training.  

ERIC Educational Resources Information Center

This self-paced student training module on cutting tools, files, and abrasives is one of a number of modules developed for Pre-apprenticeship Phase 1 Training. Purpose of the module is to enable students to identify and explain the proper use and care of various knives, saws, snips, chisels, and abrasives. The module may contain some or all of the…

Lane Community Coll., Eugene, OR.

383

The evaluation of tribo-corrosion synergy for WC–Co hardmetals in low stress abrasion  

Microsoft Academic Search

WC-based hardmetals are materials that are widely used in applications where abrasion resistance is required. This paper describes the results of tests that were performed using a modified ASTM G65 rubber wheel test system incorporating an abrasive (silica sand) and media (sulphuric acid, deionised water, and calcium hydroxide solution). The first of these media was used in order to simulate

A. J Gant; M. G Gee; A. T May

2004-01-01

384

Behaviour of iron-based hardfacing alloys under abrasion and impact  

Microsoft Academic Search

Iron-based hardfacing alloys are widely used to protect machinery equipment exposed either to pure abrasion or to a combination of abrasion and impact. The specific wear behaviour of a welding alloy under these conditions depends on its chemical composition, the microstructure obtained after welding and finally the welding technology used to apply them respectively the parameter settings which strongly influence,

M. Kirchgaßner; E. Badisch; F. Franek

2008-01-01

385

Effect of Source of Fly Ash on Abrasion Resistance of Concrete  

E-print Network

Effect of Source of Fly Ash on Abrasion Resistance of Concrete Tarun R. Naik1 ; Shiw S. Singh2 and amount of fly ash on abrasion resistance of concrete. A reference concrete was proportioned to have a 28-day age strength of 41 MPa. Three sources of Class C fly ash were used in this research. From each

Wisconsin-Milwaukee, University of

386

Study on the performance and evaluating indexes of magnetic abrasive grains  

Microsoft Academic Search

Magnetic abrasive grains (MAG) are of importance to magnetic abrasive finishing. However, the theoretical studies on MAG are lack in depth and extents, till today, the researches on performance indexes of MAG have been part of blank space. At present, the indexes of evaluating properties of MAG are inconsistent, which, to a great extent, results in imperfection of preparation of

H. L. Chen; W. H. Li; S. C. Yang

2009-01-01

387

Functional role of the structural constituents of the particles of magnetic abrasive powder  

Microsoft Academic Search

As the result of comparison of the service properties of cast magnetic abrasive powders with the same type of structure but different physicochemical properties of the constituents an evaluation was made of the abrasive properties of the latter in polishing of various materials. It was shown that by changing practically only the composition of the solid solution or of the

V. E. Oliker; A. F. Zhornyak; T. Ya. Gridasova; K. N. Chebotareva

1985-01-01

388

Characterization of the Magnetic Abrasive Finishing Method and Its Application to Deburring  

Microsoft Academic Search

This paper analyzes the effectiveness of using Magnetic Abrasive Finishing (MAF) to remove burrs on drilled holes located on planes. Basic elements of the equipment in this method are a magnetic inductor; powder with magnetic and abrasive properties, which serves as the cutting tool; and the face electromagnetic inductor and the vibrating table, which were developed for deburring and finishing

Yuri M. Baron; S.-L. Ko; Jung Il Park

2005-01-01

389

Influence of cutting speed on the effectiveness of polishing with magnetic abrasive powders  

Microsoft Academic Search

In comparison with composite ones cast magnetic abrasive powder, the particles of which are a dispersed system of a ferromagnetic medium and an abrasive phase, makes it possible to polish at higher rates. At the same time removal of metal and the process of attaining the necessary machined surface finish are accelerated.

V. E. Oliker; A. F. Zhornyak; T. Ya. Gridasova

1983-01-01

390

An AFM study of single-contact abrasive wear: The Rabinowicz wear equation revisited  

Microsoft Academic Search

A nanoscale study of the abrasive wear behaviour of a ductile monophasic metallic alloy (the stainless steel AISI 316L) is presented. By using atomic force microscopy (AFM) based techniques, particularly a diamond tip mounted on a stiff steel cantilever, the contact of a single abrasive asperity was simulated, and it was possible to determine accurately the load threshold below which

R. Colaço

2009-01-01

391

Can scratch testing be used as a model for the abrasive wear of hard coatings?  

Microsoft Academic Search

Hardness testing has often been used to give a guide to the abrasive wear resistance of materials since an approximately linear correlation between wear resistance and hardness has been observed for broadly similar materials. However, the abrasive wear behaviour of a range of thin hard coatings has been found to vary quite dramatically and no reliable correlation with hardness exists.

S. J Bull

1999-01-01

392

Investigation into the mechanisms of closed three-body abrasive wear  

Microsoft Academic Search

Contacting components frequently fail by abrasion caused by solid contaminants in the lubricant. This process can be classified as a closed three-body abrasive wear process. The mechanisms by which trapped particles cause material removal are not fully understood. This paper describes tests using model elastohydrodynamic contacts to study these mechanisms. An optical elastohydrodynamic lubrication rig has been used to study

R. S. Dwyer-Joyce; R. S. Sayles; E. Ioannides

1994-01-01

393

Determining the steel media abrasive wear as a function of applied force and friction  

Microsoft Academic Search

In the ongoing effort to develop a tumbling mill total steel media wear model, a decoupled abrasive, corrosive and impact wear model is used in conjunction with a mill DEM charge motion model. In order to determine the contribution of abrasive wear to total steel media wear in mills as a function of charge motion, it is necessary to determine

Tapiwa Chenje; Peter Radziszewski

2004-01-01

394

Effect of the belt grinding on the surface texture: Modeling of the contact and abrasive wear  

Microsoft Academic Search

Belt grinding is a finishing manufacturing process, which usually follows a hard turning operation. Experimental investigations show that the belt grinding process improves the surface texture and leads to compressive residual stresses.To study the contact between the belt constituted by abrasive grains and the surface, in particular to understand the physical of abrasion, a three-dimensional numerical model is established and

A. Jourani; M. Dursapt; H. Hamdi; J. Rech; H. Zahouani

2005-01-01

395

Computational investigation of microstructural effects on abrasive wear of composite materials  

Microsoft Academic Search

Abrasive wear of composite materials is a complicated surface damage process, affected by a number of factors, such as microstructure, mechanical properties of the target material and the abrasive, loading condition, environmental influence, etc. Microstructure is one of the major factors; however, its effect on the wear mechanism is difficult to investigate experimentally due to the possible synergism with other

J. Hu; D. Y. Li; R. Llewellyn

2005-01-01

396

ABRASIVE FLOW MACHINING WITH ADDITIONAL CENTRIFUGAL FORCE APPLIED TO THE MEDIA  

Microsoft Academic Search

Abrasive flow machining (AFM) is one of the important non-traditional metal finishing technologies which was introduced during the late 1960s. The process has found applications in a wide range of fields such as aerospace, defence, surgical and tool manufacturing industries. Recently, an effort has been made towards the performance improvement of this process by applying centrifugal force on the abrasive

R. S. Walia; H. S. Shan; P. Kumar

2006-01-01

397

Experimental Studies on Mechanism of Material Removal in Abrasive Flow Machining Process  

Microsoft Academic Search

In this article, the mechanism of material removal (MR) in Abrasive Flow Machining (AFM) process has been studied. Representative components of pure Aluminum and Brass were processed by AFM under similar process conditions. The processed surfaces were analyzed with the help of Scanning Electron Microscopy (SEM). SEM photographs reveal noticeable difference between abrasion patterns produced on the processed surfaces of

Sehijpal Singh; H. S. Shan; Pradeep Kumar

2008-01-01

398

Abrasive wear due to the slow flow of a concentrated suspension  

Microsoft Academic Search

A mechanism for abrasive wear resulting from slow flows of concentrated hard particle suspensions is described. The key to this mechanism is the development of a dispersive particle-phase pressure which is shown to lead to particle contacts with the surfaces bounding the flow. Analytical descriptions of the development of an abrasive traction are compared to finite element simulations. These analytical

J. J. Haan; P. S. Steif

1998-01-01

399

Modeling of material removal and surface roughness in abrasive flow machining process  

Microsoft Academic Search

Abrasive flow machining process provides a high level of surface finish and close tolerances with an economically acceptable rate of surface generation for a wide range of industrial components. This paper deals with the theoretical investigations into the mechanism of abrasive flow machining (AFM) process. A finite element model is developed for the flow of media during AFM and the

Rajendra K. Jain; Vijay K. Jain; P. M. Dixit

1999-01-01

400

Temperature as sensitive monitor for efficiency of work in abrasive flow machining  

Microsoft Academic Search

Work efficiency is considered as most concerned target in abrasive flow machining (AFM). It has many influence factors, such as, temperature, media viscosity, abrasive hardness, particles sharpness and density, workpiece hardness, pressure, piston moving speed, etc. The influence of temperature on work efficiency is most critical. In this investigation, both commercial AFM equipment and test rig are used to carry

Liang Fang; Jia Zhao; Kun Sun; Degang Zheng; Dexin Ma

2009-01-01

401

Rock coatings and aeolian abrasion on Mars: Application to the Pathfinder landing site  

Microsoft Academic Search

Rock coatings can be used to constrain the rate of abrasion by wind on Mars. The susceptibility to abrasion for potential rock coatings on Mars (salt\\/salt-cemented coatings, rock varnish, and amorphous silica) were determined experimentally. Rock coatings generally abrade more easily than the host rock, although amorphous silica is an exception. If coatings exist on rocks at the Mars Pathfinder

Michael D. Kraft; Ronald Greeley

2000-01-01

402

Test rig design and experimental results of coated systems under impact abrasion conditions  

Microsoft Academic Search

The design of a wear test apparatus for combining the effects of impact and abrasion was investigated for testing coated and uncoated materials. Tests consisting of abrasion, impact and their combined effects were carried out on thermally sprayed WC?Co and Ni?Cr coated aluminum and mild steel and compared to uncoated samples. The abrading reciprocating stylus, whose velocity continually changed along

D. M. Kennedy; M. S. J. Hashmi

1996-01-01

403

Effect of stress on abrasive and erosive wear of steels and sprayed coatings  

Microsoft Academic Search

The effect of stress on abrasive and erosive wear was studied for the hypoeutectoid steel, two hypereutectoid tool steels and flame sprayed coatings. In the experiment, the specially designed tester as well as SEM and contact profilometer were applied. Abrasion and erosion remove asperities protruding from the surface of coatings. The imposed stress increased erosive wear of coatings. Application of

Andrzej Wero?ski; Tadeusz Hejwowski

2008-01-01

404

Adapting blasting technologies to the characteristics of rock masses in order to improve blasting results and reduce blasting vibrations  

Microsoft Academic Search

The complex interrelations between rock properties and variable technological drilling and blasting parameters is statistically analysed. The blastability of rock mass is defined by means of the acoustic impedance of the rock and the block size in situ.In addition, an equation derived from a statistical consideration facilitates an approximate determination of the specific blasting effect, Sg. For this purpose the

B. Müller

1997-01-01

405

Paint removal and surface cleaning using ice particles  

NASA Astrophysics Data System (ADS)

Research into the possibility of using ice particles as a blast medium was first initiated at Defence Research Establishment Pacific (DREP) in an effort to develop a more environmentally acceptable paint removal method. A paint removal process was also required that could be used in areas where normal grit blasting could not be used due to the possibility of the residual blasting grit contaminating machinery and other equipment. As a result of this research a commercial ice blasting system was developed by RETECH. This system is now being used to remove paint from substrates that cannot be easily blasted by conventional techniques and also to clean soiled or contaminated surfaces. The problems involved in the development of an ice blast system, and its components and their functions are described. Due to the complexity of paint removal using ice blasting, parameters such as air pressure, ice particle size and ice particle flow rate were studied and adjusted to suit the nature of the particular coating and substrate of interest. The mechanism of paint removal by ice particles has also been investigated. A theoretical model has been developed to explain the different paint removal mechanisms such as erosion by abrasion and erosion by fracture as they relate to ice blasting. Finally, the use of ice blasting to removal paint from a variety of substrates is presented as well as examples of surface cleaning and surface decontamination.

Foster, Terry; Visaisouk, S.

1993-03-01

406

Paint removal and surface cleaning using ice particles  

NASA Astrophysics Data System (ADS)

Research into the possibility of using ice particles as a blast medium was first initiated at Defence Research Establishment Pacific (DREP) in an effort to develop a more environmentally acceptable paint removal method. A paint removal process was also required that could be used in areas where normal grit blasting could not be used due to the possibility of the residual blasting grit contaminating machinery and other equipment. As a result of this research a commercial ice blasting system was developed by RETECH. This system is now being used to remove paint from substrates that cannot be easily blasted by conventional techniques and also to clean soiled or contaminated surfaces. The problems involved in the development of an ice blast system and its components and their functions are described. Due to the complexity of paint removal using ice blasting, parameters such as air pressure, ice particle size and ice particle flow rate were studied and adjusted to suit the nature of the particular coating and substrate of interest. The mechanism of paint removal by ice particles has also been investigated. A theoretical model has been developed to explain the different paint removal mechanisms such as erosion by abrasion and erosion by fracture as they relate to ice blasting. Finally, the use of ice blasting to removal paint from a variety of substrates is presented as well as examples of surface cleaning and surface decontamination.

Foster, Terry; Visaisouk, S.

1995-04-01

407

Zinc recovery from blast furnace flue dust  

Microsoft Academic Search

Blast furnace flue dusts are a mixture of oxides expelled from the top of the blast furnace, whose major components are iron oxides. They also contain zinc, silicon, magnesium and other minor element oxides in lesser amounts. The direct recycling of flue dust is not usually possible since it contains some undesirable elements (zinc and alkaline metals) that can cause

B. Asadi Zeydabadi; D. Mowla; M. H. Shariat; J. Fathi Kalajahi

1997-01-01

408

Existing and prospective blast-furnace conditions  

SciTech Connect

Blast-furnace conditions are investigated by means of a multizone model. The expected performance of prospective technologies is assessed, as well as the trends in blast-furnace processes. The model permits the identification of means of overcoming practical difficulties.

I.G. Tovarovskii; V.I. Bol'shakov; V.P. Lyalyuk; A.E. Merkulov; D. V. Pinchuk [Ukrainian Academy of Sciences, Dnepropetrovsk (Ukraine). Institute of Ferrous Metallurgy

2009-07-15

409

Color changing photonic crystals detect blast exposure  

PubMed Central

Blast-induced traumatic brain injury (bTBI) is the “signature wound” of the current wars in Iraq and Afghanistan. However, with no objective information of relative blast exposure, warfighters with bTBI may not receive appropriate medical care and are at risk of being returned to the battlefield. Accordingly, we have created a colorimetric blast injury dosimeter (BID) that exploits material failure of photonic crystals to detect blast exposure. Appearing like a colored sticker, the BID is fabricated in photosensitive polymers via multi-beam interference lithography. Although very stable in the presence of heat, cold or physical impact, sculpted micro- and nano-structures of the BID are physically altered in a precise manner by blast exposure, resulting in color changes that correspond with blast intensity. This approach offers a lightweight, power-free sensor that can be readily interpreted by the naked eye. Importantly, with future refinement this technology may be deployed to identify soldiers exposed to blast at levels suggested to be supra-threshold for non-impact blast-induced mild TBI. PMID:21040795

Cullen, D. Kacy; Xu, Yongan; Reneer, Dexter V.; Browne, Kevin D.; Geddes, James W.; Yang, Shu; Smith, Douglas H.

2010-01-01

410

The Grits Line  

E-print Network

66.4% 196 West South Central 48.9% 133 32.7% 146 52.0% 131 38.9% 128 46.2% 139 44.7% 132 West North Central 50.1% 136 27.1% 121 54.5% 137 31.3% 103 45.4% 137 42.9% 127 South Atlantic 42.6% 116 26.6% 119 46.0% 116 31.0% 102 39.2% 118 38.9% 115... Mountain 32.0% 87 19.0% 85 35.0% 88 28.1% 92 28.1% 85 30.2% 89 East North Central 32.1% 87 16.8% 75 35.6% 90 28.3% 93 27.2% 82 30.0% 89 Middle Atlantic 23.8% 65 15.9% 71 25.9% 65 30.2% 99 21.4% 65 26.1% 77 Pacific 20.6% 56 14.9% 67 22.1% 56 26...

Whitworth, Jim

2006-11-15

411

On the Propagation and Interaction of Spherical Blast Waves  

NASA Technical Reports Server (NTRS)

The characteristics and the scaling laws of isolated spherical blast waves have been briefly reviewed. Both self-similar solutions and numerical solutions of isolated blast waves are discussed. Blast profiles in the near-field (strong shock region) and the far-field (weak shock region) are examined. Particular attention is directed at the blast overpressure and shock propagating speed. Consideration is also given to the interaction of spherical blast waves. Test data for the propagation and interaction of spherical blast waves emanating from explosives placed in the vicinity of a solid propellant stack are presented. These data are discussed with regard to the scaling laws concerning the decay of blast overpressure.

Kandula, Max; Freeman, Robert

2007-01-01

412

Statistical Analysis of Magnetic Abrasive Finishing (MAF) On Surface Roughness  

NASA Astrophysics Data System (ADS)

Magnetic assisted finishing is one of the nontraditional methods of polishing that recently has been attractive for the researchers. This paper investigates the effects of some parameters such as rotational speed of the permanent magnetic pole, work gap between the permanent pole and the work piece, number of the cycles and the weight of the abrasive particles on aluminum surface plate finishing. The three levels full factorial method was used as the DOE technique (design of experiments) for studying the selected factors. Analysis of Variance (ANOVA) has been used to determine significant factors and also to obtain an equation based on data regression. Experimental results indicate that for a change in surface roughness ?Ra, number of cycles and working gap are found to be the most significant parameters followed by rotational speed and then weight of powders.

Givi, Mehrdad; Tehrani, Alireza Fadaei; Mohammadi, Aminollah

2010-06-01

413

Fatigue Testing of Abrasive Water Jet Cut Titanium  

SciTech Connect

Battelle Memorial Institute as part of its U.S. Department of Energy (USDOE) Contract No. DE-AC05-76RL01830 to operate the Pacific Northwest National Laboratory (PNNL) provides technology assistance to qualifying small businesses in association with a Technology Assistance Program (TAP). Qualifying companies are eligible to receive a set quantity of labor associated with specific technical assistance. Having applied for a TAP agreement to assist with fatigue characterization of Abrasive Water Jet (AWJ) cut titanium specimens, the OMAX Corporation was awarded TAP agreement 09-02. This program was specified to cover dynamic testing and analysis of fatigue specimens cut from titanium alloy Ti-6%Al-4%V via AWJ technologies. In association with the TAP agreement, a best effort agreement was made to characterize fatigue specimens based on test conditions supplied by OMAX.

Hovanski, Yuri; Dahl, Michael E.; Williford, Ralph E.

2009-06-08

414

Estimating rock compressive strength from Rock Abrasion Tool (RAT) grinds  

NASA Astrophysics Data System (ADS)

Each Mars Exploration Rover carries a Rock Abrasion Tool (RAT) whose intended use was to abrade the outer surfaces of rocks to expose more pristine material. Motor currents drawn by the RAT motors are related to the strength and hardness of rock surfaces undergoing abrasion, and these data can be used to infer more about a target rock's physical properties. However, no calibration of the RAT exists. Here, we attempt to derive an empirical correlation using an assemblage of terrestrial rocks and apply this correlation to data returned by the rover Spirit. The results demonstrate a positive correlation between rock strength and RAT grind energy for rocks with compressive strengths less than about 150 MPa, a category that includes all but the strongest intact rocks. Applying this correlation to rocks abraded by Spirit's RAT, the results indicate a large divide in strength between more competent basaltic rocks encountered in the plains of Gusev crater (Adirondack-class rocks) and the weaker variety of rock types measured in the Columbia Hills. Adirondack-class rocks have estimated compressive strengths in the range of 70-130 MPa and are significantly less strong than fresh terrestrial basalts; this may be indicative of a degree of weathering-induced weakening. Rock types in the Columbia Hills (Wishstone, Watchtower, Clovis, and Peace class) all have compressive strengths <50 MPa and are consistent with impactites or volcanoclastic materials. In general, when considered alongside chemical, spectral, and rock textural data, these inferred compressive strength results help inform our understanding of rock origins and modification history.

Thomson, B. J.; Bridges, N. T.; Cohen, J.; Hurowitz, J. A.; Lennon, A.; Paulsen, G.; Zacny, K.

2013-06-01

415

Study of Abrasive Wear Volume Map for PTFE and PTFE Composites  

NASA Astrophysics Data System (ADS)

The potential of this work is based on consideration of wear volume map for the evaluation of abrasive wear performance of polytetrafluoroethylene (PTFE) and PTFE composites. The fillers used in the composite are 25% bronze, 35% graphite and 17% glass fibre glass (GFR). The influence of filler materials, abrasion surface roughness and applied load values on abrasive wear performance of PTFE and PTFE composites were studied and evaluated. Experimental abrasive wear tests were carried out at atmospheric condition on pin-on-disc wear tribometer. Tests were performed under 4, 6, 8 and 10 N load values, travelling speed of 1 m/sec and abrasion surface roughness values of 5, 20 and 45 µm. Wear volume maps were obtained and the results showed that the lowest wear volume rate for PTFE is reached using GFR filler. Furthermore, the results also showed that the higher is the applied load and the roughness of the abrasion surface, the higher is the wear rate. Finally it is also concluded that abrasive wear process mechanism include ploughing and cutting mechanisms.

Unal, H.; Sen, U.; Mimaroglu, A.

2007-11-01

416

Relationships Between Abrasive Wear, Hardness, and Grinding Characteristics of Titanium-Based Metal-Matrix Composites  

NASA Astrophysics Data System (ADS)

The objective of this work was to support the development of grinding models for titanium metal-matrix composites (MMCs) by investigating possible relationships between their indentation hardness, low-stress belt abrasion, high-stress belt abrasion, and the surface grinding characteristics. Three Ti-based particulate composites were tested and compared with the popular titanium alloy Ti-6Al-4V. The three composites were a Ti-6Al-4V-based MMC with 5% TiB2 particles, a Ti-6Al-4V MMC with 10% TiC particles, and a Ti-6Al-4V/Ti-7.5%W binary alloy matrix that contained 7.5% TiC particles. Two types of belt abrasion tests were used: (a) a modified ASTM G164 low-stress loop abrasion test, and (b) a higher-stress test developed to quantify the grindability of ceramics. Results were correlated with G-ratios (ratio of stock removed to abrasives consumed) obtained from an instrumented surface grinder. Brinell hardness correlated better with abrasion characteristics than microindentation or scratch hardness. Wear volumes from low-stress and high-stress abrasive belt tests were related by a second-degree polynomial. Grindability numbers correlated with hard particle content but were also matrix-dependent.

Blau, Peter J.; Jolly, Brian C.

2009-06-01

417

The prevalence and risk factors associated with forelimb skin abrasions and sole bruising in preweaning piglets.  

PubMed

The presence of skin abrasions and sole bruising in 264 preweaning piglets (1-30 days old) from 13 breeding units in south west England was investigated in 1995. The mean prevalence of forelimb skin abrasions among the pigs on the study farms was 36% (range 0-59%) and sole bruising was 50% (range 0-95%). Skin abrasions were located on three aspects on the front limbs: the carpus, the metacarpus and the digit. Lesions occurred early in a piglet's life; the modal ages for sole bruising was 4 days and for skin abrasions were 5 and 10 days. The presence of skin abrasions on the front limbs was significantly associated with the presence of sole bruising on the front feet. Logistic regression indicated that part-concrete, part-round-mesh (OR 56.4) and part-concrete, part-metal-rods floors (OR 15.9) and exposed aggregate (OR 4.6) were associated with an increased odds of sole bruising while the presence of sparse straw (OR 0.12) or deep straw (OR 0.12) in the pen was associated with lower odds of sole bruising. The same floor type (part-concrete, part-round-mesh) was associated with increased odds of forelimb skin abrasions (OR 2.2). A worn floor surface where the solid adjoined the perforated area (OR 4.6) and the presence of sparse shavings (OR 1.7) were also associated with an increased risk of skin abrasions. PMID:10327440

Mouttotou, N; Hatchell, F M; Green, L E

1999-04-27

418

Relationships Between Abrasive Wear, Hardness, and Surface Grinding Characteristics of Titanium-Based Metal Matrix Composites  

SciTech Connect

The objective of this work was to support the development of grinding models for titanium metal-matrix composites (MMCs) by investigating possible relationships between their indentation hardness, low-stress belt abrasion, high-stress belt abrasion, and the surface grinding characteristics. Three Ti-based particulate composites were tested and compared with the popular titanium alloy Ti-6Al-4V. The three composites were a Ti-6Al-4V-based MMC with 5% TiB{sub 2} particles, a Ti-6Al-4V MMC with 10% TiC particles, and a Ti-6Al-4V/Ti-7.5%W binary alloy matrix that contained 7.5% TiC particles. Two types of belt abrasion tests were used: (a) a modified ASTM G164 low-stress loop abrasion test, and (b) a higher-stress test developed to quantify the grindability of ceramics. Results were correlated with G-ratios (ratio of stock removed to abrasives consumed) obtained from an instrumented surface grinder. Brinell hardness correlated better with abrasion characteristics than microindentation or scratch hardness. Wear volumes from low-stress and high-stress abrasive belt tests were related by a second-degree polynomial. Grindability numbers correlated with hard particle content but were also matrix-dependent.

Blau, Peter Julian [ORNL; Jolly, Brian C [ORNL

2009-01-01

419

Linear abrasion of a titanium superhydrophobic surface prepared by ultrafast laser microtexturing  

NASA Astrophysics Data System (ADS)

A novel method of fabricating titanium superhydrophobic surfaces by ultrafast laser irradiation is reported. The ultrafast laser irradiation creates self-organized microstructure superimposed with nano-scale roughness, after which a fluoropolymer coating is applied to lower the surface energy of the textured surface and achieve superhydrophobicity. The focus of this study is to investigate abrasion effects on this mechanically durable superhydrophobic surface. The mechanical durability is analyzed with linear abrasion testing and microscopy imaging. Linear abrasion tests indicate that these surfaces can resist complete microstructure failure up to 200 abrasion cycles and avoid droplet pinning up to ten abrasion cycles at 108.4 kPa applied pressure, which roughly corresponds to moderate to heavy sanding or rubbing in the presence of abrasive particles. The wear mechanisms are also investigated and the primary mechanism for this system is shown to be abrasive wear with fatigue by repeated plowing. Although these results demonstrate an advancement in mechanical durability over the majority of existing superhydrophobic surfaces, it exemplifies the challenge in creating superhydrophobic surfaces with suitable mechanical durability for harsh applications, even when using titanium.

Steele, Adam; Nayak, Barada K.; Davis, Alexander; Gupta, Mool C.; Loth, Eric

2013-11-01

420

Neuro-Glial and Systemic Mechanisms of Pathological Responses in Rat Models of Primary Blast Overpressure Compared to "Composite" Blast  

PubMed Central

A number of experimental models of blast brain injury have been implemented in rodents and larger animals. However, the variety of blast sources and the complexity of blast wave biophysics have made data on injury mechanisms and biomarkers difficult to analyze and compare. Recently, we showed the importance of rat position toward blast generated by an external shock tube. In this study, we further characterized blast producing moderate traumatic brain injury and defined “composite” blast and primary blast exposure set-ups. Schlieren optics visualized interaction between the head and a shock wave generated by external shock tube, revealing strong head acceleration upon positioning the rat on-axis with the shock tube (composite blast), but negligible skull movement upon peak overpressure exposure off-axis (primary blast). Brain injury signatures of a primary blast hitting the frontal head were assessed and compared to damage produced by composite blast. Low to negligible levels of neurodegeneration were found following primary blast compared to composite blast by silver staining. However, persistent gliosis in hippocampus and accumulation of GFAP/CNPase in circulation was detected after both primary and composite blast. Also, markers of vascular/endothelial inflammation integrin alpha/beta, soluble intercellular adhesion molecule-1, and L-selectin along with neurotrophic factor nerve growth factor-beta were increased in serum within 6?h post-blasts and persisted for 7?days thereafter. In contrast, systemic IL-1, IL-10, fractalkine, neuroendocrine peptide Orexin A, and VEGF receptor Neuropilin-2 (NRP-2) were raised predominantly after primary blast exposure. In conclusion, biomarkers of major pathological pathways were elevated at all blast set-ups. The most significant and persistent changes in neuro-glial markers were found after composite blast, while primary blast instigated prominent systemic cytokine/chemokine, Orexin A, and Neuropilin-2 release, particularly when primary blast impacted rats with unprotected body. PMID:22403567

Svetlov, Stanislav I.; Prima, Victor; Glushakova, Olena; Svetlov, Artem; Kirk, Daniel R.; Gutierrez, Hector; Serebruany, Victor L.; Curley, Kenneth C.; Wang, Kevin K. W.; Hayes, Ronald L.

2012-01-01

421

ScalaBLAST 2.0: rapid and robust BLAST calculations on multiprocessor systems  

PubMed Central

Motivation: BLAST remains one of the most widely used tools in computational biology. The rate at which new sequence data is available continues to grow exponentially, driving the emergence of new fields of biological research. At the same time, multicore systems and conventional clusters are more accessible. ScalaBLAST has been designed to run on conventional multiprocessor systems with an eye to extreme parallelism, enabling parallel BLAST calculations using >16 000 processing cores with a portable, robust, fault-resilient design that introduces little to no overhead with respect to serial BLAST. Availability: ScalaBLAST 2.0 source code can be freely downloaded from http://omics.pnl.gov/software/ScalaBLAST.php. Contact: christopher.oehmen@pnl.gov PMID:23361326

Oehmen, Christopher S.; Baxter, Douglas J.

2013-01-01

422

Investigation of atmospheric blasts by fast radiometry  

NASA Astrophysics Data System (ADS)

Blasts and detonations release large amount of energy in short time duration. Some of this energy is released through radiation in the whole optical spectrum. Measurement of this radiation may serve as a base for investigation of the blast phenomena. A fast multispectral radiometer that operates in proper chosen spectral bands provides extensive information on the physical processes that govern the blast. This information includes the time dependence of the temperature, area of the blast as-well-as of the aerosols and gases that are generated. Analysis of this data indicates the order of the detonation and provides good estimation on the masses and types of the high-explosives (HE) materials and their casing. This paper presents the methodology and instrumentation of fast multispectral radiometry in application to the blast measurement and analysis in a Near-ground Explosion Test (NET). In NET, the flash radiation of the blast was measured for two HE materials: TNT and composition B (CB). The investigation includes charges of different masses (0.25 - 20.0 kg) and of various casing materials (steel, Al, PVC), thickness (2 - 6 mm) and various casing type (open on both face ends and hermetically closed). Analysis of the data demonstrates the power of fast radiometry methodology and reveals the governing characteristics of atmospheric blasts.

Ben-Dov, R.; Bushlin, Y.; Devir, A. D.; Lessin, A. B.; Mendelewicz, I.; Shvebelman, M.

2014-06-01

423

Blast investigation by fast multispectral radiometric analysis  

NASA Astrophysics Data System (ADS)

Knowledge regarding the processes involved in blasts and detonations is required in various applications, e.g. missile interception, blasts of high-explosive materials, final ballistics and IED identification. Blasts release large amount of energy in short time duration. Some part of this energy is released as intense radiation in the optical spectral bands. This paper proposes to measure the blast radiation by a fast multispectral radiometer. The measurement is made, simultaneously, in appropriately chosen spectral bands. These spectral bands provide extensive information on the physical and chemical processes that govern the blast through the time-dependence of the molecular and aerosol contributions to the detonation products. Multi-spectral blast measurements are performed in the visible, SWIR and MWIR spectral bands. Analysis of the cross-correlation between the measured multi-spectral signals gives the time dependence of the temperature, aerosol and gas composition of the blast. Farther analysis of the development of these quantities in time may indicate on the order of the detonation and amount and type of explosive materials. Examples of analysis of measured explosions are presented to demonstrate the power of the suggested fast multispectral radiometric analysis approach.

Devir, A. D.; Bushlin, Y.; Mendelewicz, I.; Lessin, A. B.; Engel, M.

2011-06-01

424

Abrasive wear by coal-fueled diesel engine and related particles  

SciTech Connect

The development of commercially viable diesel engines that operate directly on pulverized coal-fuels will require solution to the problem of severe abrasive wear. The purpose of the work described in this report was to investigate the nature of the abrasive wear problem. Analytical studies were carried out to determine the characteristics of the coal-fuel and associated combustion particles responsible for abrasion. Laboratory pinon-disk wear tests were conducted on oil-particle mixtures to determine the relationship between wear rate and a number of different particle characteristics, contact parameters, specimen materials properties, and other relevant variables.

Ives, L.K. [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1992-09-01

425

Optical-model abrasion cross sections for high-energy heavy ions  

NASA Technical Reports Server (NTRS)

Within the context of eikonal scattering theory, a generalized optical model potential approximation to the nucleus-nucleus multiple scattering series is used in an abrasion-ablation collision model to predict abrasion cross sections for relativistic projectile heavy ions. Unlike the optical limit of Glauber theory, which cannot be used for very light nuclei, the abrasion formalism is valid for any projectile target combination at any incident kinetic energy for which eikonal scattering theory can be utilized. Results are compared with experimental results and predictions from Glauber theory.

Townsend, L. W.

1981-01-01

426

Target correlation effects on neutron-nucleus total, absorption, and abrasion cross sections  

NASA Astrophysics Data System (ADS)

Second order optical model solutions to the elastic scattering amplitude were used to evaluate total, absorption, and abrasion cross sections for neutron nucleus scattering. Improved agreement with experimental data for total and absorption cross sections is found when compared with first order (coherent approximation) solutions, especially below several hundred MeV. At higher energies, the first and second order solutions are similar. There are also large differences in abrasion cross section calculations; these differences indicate a crucial role for cluster knockout in the abrasion step.

Cucinotta, Francis A.; Townsend, Lawrence W.; Wilson, John W.

1991-12-01

427

Three-Body Abrasion Testing Using Lunar Dust Simulants to Evaluate Surface System Materials  

NASA Technical Reports Server (NTRS)

Numerous unexpected operational issues relating to the abrasive nature of lunar dust, such as scratched visors and spacesuit pressure seal leaks, were encountered during the Apollo missions. To avoid reoccurrence of these unexpected detrimental equipment problems on future missions to the Moon, a series of two- and three-body abrasion tests were developed and conducted in order to begin rigorously characterizing the effect of lunar dust abrasiveness on candidate surface system materials. Two-body scratch tests were initially performed to examine fundamental interactions of a single particle on a flat surface. These simple and robust tests were used to establish standardized measurement techniques for quantifying controlled volumetric wear. Subsequent efforts described in the paper involved three-body abrasion testing designed to be more representative of actual lunar interactions. For these tests, a new tribotester was developed to expose samples to a variety of industrial abrasives and lunar simulants. The work discussed in this paper describes the three-body hardware setup consisting of a rotating rubber wheel that applies a load on a specimen as a loose abrasive is fed into the system. The test methodology is based on ASTM International (ASTM) B611, except it does not mix water with the abrasive. All tests were run under identical conditions. Abraded material specimens included poly(methyl methacrylate) (PMMA), hardened 1045 steel, 6061-T6 aluminum (Al) and 1018 steel. Abrasives included lunar mare simulant JSC- 1A-F (nominal size distribution), sieved JSC-1A-F (<25 m particle diameter), lunar highland simulant NU-LHT-2M, alumina (average diameter of 50 m used per ASTM G76), and silica (50/70 mesh used per ASTM G65). The measured mass loss from each specimen was converted using standard densities to determine total wear volume in cm3. Abrasion was dominated by the alumina and the simulants were only similar to the silica (i.e., sand) on the softer materials of aluminum and PMMA. The nominal JSC- 1A-F consistently showed more abrasion wear than the sieved version of the simulant. The lunar dust displayed abrasivity to all of the test materials, which are likely to be used in lunar landing equipment. Based on this test experience and pilot results obtained, recommendations are made for systematic abrasion testing of candidate materials intended for use in lunar exploration systems and in other environments with similar dust challenges.

Kobrick, Ryan L.; Budinski, Kenneth G.; Street, Kenneth W., Jr.; Klaus, David M.

2010-01-01

428

High Resolution Laser Scanning Techniques for Rock Abrasion and Texture Analyses on Mars and Earth  

NASA Technical Reports Server (NTRS)

Aeolian abrasion is operative in many arid locations on Earth and is probably the dominant rock erosion process in the current Martian environment. Therefore, understanding the controlling parameters and rates of aeolian abrasion provides 1) insight into the stability of rocks on planetary surfaces and the environments under which the rocks abrade, and 2) a link between ventifact (a rock abraded by windblown particles) morphology and: a) abrasion conditions, b) possible ancient environments under which the rocks were abraded, and c) rock properties. promising and we plan further investigations in the wind tunnel and field. Our intent here is to discuss the basic technique, initial results, and upcoming plans.

Bridges, N. T.; Razdan, A.; Greeley, R.; Laity, J. E.

2004-01-01

429

Chemical Mechanical Polishing of Ge2Sb2Te5 Using Abrasive-Free Solutions of Iron Trichloride  

NASA Astrophysics Data System (ADS)

Chemical mechanical polishing (CMP) of amorphous Ge2Sb2Te5 (GST) is studied using aqueous solutions of iron trichloride (FeCl3) as possible abrasive-free slurries. The polishing performance of abrasive-free solutions is compared with abrasive-containing (3wt% colloidal silica) slurry in terms of polishing rate and surface quality. The experimental results indicate that the abrasive-free solutions have a higher polishing rate and better surface quality. In order to further investigate the polishing mechanism, post-CMP GST films using the abrasive-free solutions and abrasive-containing slurry are characterized by x-ray photoelectron spectroscopy. Finally, it is verified that the abrasive-free solutions have no influence on the electrical property of the post-CMP GST films through the resistivity test.

Yan, Wei-Xia; Wang, Liang-Yong; Zhang, Ze-Fang; He, Ao-Dong; Zhong, Min; Liu, Wei-Li; Wu, Liang-Cai; Song, Zhi-Tang

2012-03-01

430

Partnering and the WCI blast furnace reline  

SciTech Connect

In 1993, WCI Steel entered into a partnership agreement to perform a blast furnace reline. The reline included a complete rebrick from the tuyere breast to the furnace top including the tapholes. Also included was the replacement of the Paul Wurth top equipment from the receiving hoppers through the gearbox and distribution chute, a skip incline replacement, and installation of tilting runners and a casthouse roof. The bustle pipe and hot blast main were repaired. One stove was also replaced. The reline was accomplished in 36 days, wind to wind, which allowed for 29 days of construction inside the blast furnace proper.

Musolf, D.W. [WCI Steel, Inc., Warren, OH (United States)

1997-11-01

431

CO{sub 2} pellet blasting studies  

SciTech Connect

Initial tests with CO{sub 2} pellet blasting as a decontamination technique were completed in 1993 at the Idaho Chemical Processing Plant (ICPP) at the Idaho National Engineering Laboratory (INEL). During 1996, a number of additional CO{sub 2} pellet blasting studies with Alpheus Cleaning Technologies, Oak Ridge National Laboratory, and Pennsylvania State University were conducted. After the testing with Alpheus was complete, an SDI-5 shaved CO{sub 2} blasting unit was purchased by the ICPP to test and determine its capabilities before using in ICPP decontamination efforts. Results of the 1996 testing will be presented in this report.

Archibald, K.E.

1997-01-01

432

Abrasion resistance of biaxially oriented polypropylene films coated with nanocomposite hard coatings  

NASA Astrophysics Data System (ADS)

KMnO4-treated, functionalized, biaxially oriented polypropylene (BOPP) films coated with nano-silica hybrid material were synthesized. The abrasion resistance of the films was examined using a reciprocating fabric abrasion tester. Functional groups were confirmed by Fourier-transform infrared spectroscopy. Contact angle measurements were performed on the BOPP film surface to quantify the effectiveness of the functionalization. Results indicate that the abrasion resistance and roughness of the composite film were significantly affected by the modification of the BOPP film. Water surface contact angle of the modified BOPP films decreased from 90.1° to 71.4°,when KMnO4 concentration increased from 0 M to 0.25 M. Wettability of the BOPP films clearly improved after KMnO4 treatment. Abrasion resistance of the functionalized films coated with hybrid materials improved by 27.4% compared with that of the original film.

Wang, Jing; Zhu, Yaofeng; Fu, Yaqin

2013-11-01

433

[Differential approach to air-abrasion powder choice in patients with periodontal disease].  

PubMed

Using literature review data and their own clinical experience the authors compare powders for dental air-abrasion procedures and formulate differential approach to powder choice in patients with periodontal disease. PMID:23715449

Volinskaia, T B

2013-01-01

434

Particle Abrasion Within the Chicxulub Ejecta Blanket: Implications for the Emplacement Process  

NASA Astrophysics Data System (ADS)

Roundness and sphericity of 1575 clasts from 14 localities of Chicxulub ejecta blanket were measured. Increasing particle abrasion with crater distance can be related to a viscous and erosive secondary flow with increasing strain localization.

Schönian, F.; Stöffler, D.; Kenkmann, T.

2008-03-01

435

Effects of process parameters on surface roughness in abrasive waterjet cutting of aluminium  

NASA Astrophysics Data System (ADS)

Abrasive waterjet cutting is a novel machining process capable of processing wide range of hard-to-cut materials. Surface roughness of machined parts is one of the major machining characteristics that play an important role in determining the quality of engineering components. This paper shows the influence of process parameters on surface roughness ( R a) which is an important cutting performance measure in abrasive waterjet cutting of aluminium. Taguchi's design of experiments was carried out in order to collect surface roughness values. Experiments were conducted in varying water pressure, nozzle traverse speed, abrasive mass flow rate and standoff distance for cutting aluminium using abrasive waterjet cutting process. The effects of these parameters on surface roughness have been studied based on the experimental results.

Chithirai Pon Selvan, M.; Mohana Sundara Raju, N.; Sachidananda, H. K.

2012-12-01

436

Treatment of gingival hyperpigmentation with rotary abrasive, scalpel, and laser techniques: A case series.  

PubMed

Melanin pigmentation often occurs in the gingiva as a result of an abnormal deposition of melanin, due to which the gums may appear black, but the principles, techniques, and management of the problems associated with gingival melanin pigmentation are still not fully established. Depigmentation procedures such as scalpel surgery, gingivectomy with free gingival autografting, electrosurgery, cryosurgery, chemical agents such as 90% phenol and 95% alcohol, abrasion with diamond bur, Nd: YAG laser, semiconductor diode laser, and CO2 laser have been employed for removal of melanin hyper pigmentation. The following case series describes three different surgical depigmentation techniques: scalpel surgery, abrasion with rotary abrasive, and a diode laser. Better results of depigmentation were achieved with diode laser than conventional scalpel and with rotary abrasion with respect to esthetics. The results point out that lasers are an effective and a safe means to removal of hyperpigmentation from the gingiva. Healing was uneventful and no repigmentation occurred. PMID:23493062

Murthy, M Bhanu; Kaur, Jasjit; Das, Rupali

2012-10-01

437

Abrasion-Resistant Aluminized-Coated Aramid Fabrics for Manufacture of Firefighters' Protective Clothing.  

National Technical Information Service (NTIS)

The required yardage of two experimental approaches to developing an abrasion resistant fabric for firefighters protective clothing has been delivered to NCTRF, Natick, MA, for fabrication into uniforms. The first is an electron-beam (EB) cured coating on...

R. Brenneman

1985-01-01

438

Abrasion mode of a circular cylindrical concrete structure due to sea ice movement  

SciTech Connect

The estimation method for the abrasions of a cylindrical concrete structure due to sea ice movement proposed by Itoh et al. (1994) is extended to precisely predict the abrasion mode near the waterline of the concrete structure. The extended distinct element method (EDEM) by Meguro and Hakuno (1989) is applied to evaluate the ice contact pressure distribution on the waterline assuming that the failure modes of the ice sheet be radial cracking and crushing. With a proper adjustment of the material parameters, realistic failure patterns and contact pressure histories can be obtained. The authors examine the adequacy of their extended estimation method through the field investigation of abrasion on concrete. It is demonstrated that the abrasion mode of the circular cylindrical concrete structure would be mainly determined by the contact pressure distribution and the excursion of the broken pieces of the ice sheet near the waterline.

Itoh, Yoshishige; Tanaka, Yoshihiro; Delgado, A. [Taisei Corp., Tokyo (Japan); Saeki, Hiroshi [Hokkaido Univ., Sapporo (Japan)

1995-12-31

439

Blast furnace supervision and control system  

SciTech Connect

On December 1992, a group of companies headed by Techint, took over Somisa, the state-owned integrated steel plant located at San Nicolas, Province of Buenos Aires, Argentina, culminating an ambitious government privatization scheme. The blast furnace 2 went into a full reconstruction and relining in January 1995. After a 140 MU$ investment the new blast furnace 2 was started in September 1995. After more than one year of operation of the blast furnace the system has proven itself useful and reliable. The main reasons for the success of the system are: same use interface for all blast furnace areas -- operation, process, maintenance and management, (full horizontal and vertical integration); and full accessibility to all information and process tools though some restrictions apply to field commands (people empowerment). The paper describes the central system.

Remorino, M.; Lingiardi, O.; Zecchi, M. [Siderar S.A.I.C./Ingdesi, San Nicolas (Argentina)

1997-12-31

440

Perfluorocarbon vapor tagging of blasting cap detonators  

DOEpatents

A plug for a blasting cap is made of an elastomer in which is dissolved a perfluorocarbon. The perfluorocarbon is released as a vapor into the ambient over a long period of time to serve as a detectable taggant.

Dietz, Russell N. (Shoreham, NY); Senum, Gunnar I. (Patchogue, NY)

1981-01-01

441

Economical solutions to blast mitigation on bridges  

E-print Network

Mitigating the energy created from a blast has been a topic of utmost importance in the terrorism-feared world of today. Main targets of concern are passageways that are significant to a specific area, such as bridges. ...

DeRogatis, Austin (Austin Patrick)

2008-01-01

442

Blasting for fill rock, McMurdo<  

NSF Publications Database

... considered importation of fill materials. Import of such materials was found to be prohibitively ... material greater distances than from the Blast Site No. 2 area. Question 5: How much fill material ...

443

Development of an accelerated abrasion test apparatus with a standardized testing procedure  

Microsoft Academic Search

Depending on the nature of the working environment, the abrasive wear of concrete floor slabs can range from scratching or\\u000a scuffing to impact and local crushing. To assess abrasion resistance it is, therefore, necessary to have a versatile apparatus.\\u000a This investigation describes the development of a basic apparatus with three modes of action and a standardized testing procedure,\\u000a for assessing

M. Sadegzadeh; R. J. Kettle

1988-01-01

444

MICROSCOPY OF ABRASIVE-PLANED AND KNIFE-PLANED SURFACES IN WOOD-ADHESIVE BONDS  

Microsoft Academic Search

Fluorescence microscopy (FM) disclosed no differences in wood cell structure between abrasive- and knife-planed Douglas-fir joints under constant conditions. However, after a one-cycle soak-dry exposure, formation of checks along the rays were visible in both abrasive- and knife-planed samples by fluorescence microscopy. For this same exposure, scanning electron microscopy revealed many radial cracks in the S2 layer and ruptures between

Lidija Murmanis; Bryan H. River; Harold Stewart

445

Influence of abrasion on biofilm detachment: evidence for stratification of the biofilm  

Microsoft Academic Search

The objective of this paper was to understand the detachment of multispecies biofilm caused by abrasion. By submitting a biofilm\\u000a to different abrasion strengths (collision of particles), stratification of biofilm cohesion could be highlighted and related\\u000a to stratification of biofilm bacterial communities using the PCR-SSCP fingerprint method. The biofilm comprised a thick top\\u000a layer, weakly cohesive and composed of one

Alice Rochex; Anthony Massé; Renaud Escudié; Jean-Jacques Godon; Nicolas Bernet

2009-01-01

446

Abrasive wear resistance of boronized carbon and low-alloy steels  

Microsoft Academic Search

In this study, the abrasive wear resistance of previously boronized 1020, 1045, 4140 and 4340 steels were determined. The boronizing treatments were performed in a mixture of dried borax and SiC at temperatures of 1223, 1273 and 1323K, during 2, 4 and 8h. On the surface of each steel, a monophase layer of Fe2B was obtained. The abrasive wear tests

M. A. Béjar; E. Moreno

2006-01-01

447

Some remarks on particle size effects on the abrasion of a range of Fe based alloys  

Microsoft Academic Search

The low-stress three body abrasion behaviour of a range of steels was investigated. The tests were carried out in a rubber wheel tester (according to ASTM G65-94, reapproved in 2000) at room temperature. The abrasive particles used were angular alumina particles of four different sizes. The results showed that, in general, the smaller particles (50 and 125?m average size) caused

J. G. Chacon-Nava; A. Martinez-Villafañe; F. Almeraya-Calderon; J. A. Cabral-Miramontes; M. M. Stack

2010-01-01

448

Use of magnetic abrasive machining for sharpening of medical instrument blades  

Microsoft Academic Search

Conclusions 1.Magnetic abrasive machining (MAM) can be successfully applied as a finishing operation for sharpening and removal of burrs from partially-finished blades manufactured by vibroforging.2.In comparison to currently used technology of mechanical polishing and electrochemical treatment and sharpening of partially-finished blades, the proposed method of magnetic abrasive machining would allow surface defects such as burns, microscopic cracks, etching, scratching by

G. I. Altareva; L. A. Vorob'eva; R. R. Gafarov; V. D. Efremov; N. Ya. Skvorchevskii; V. N. Kalina

1992-01-01

449

Abrasive wear behavior of sintered steels prepared with MoS 2 addition  

Microsoft Academic Search

Sintered steels containing molybdenum di sulphide powders were developed for application as bearings, gears, connecting rods, etc. Abrasive wear characteristics of these materials are investigated as the machine elements also need to have a good abrasive wear resistance. Materials with base composition Fe–C–Cu and Fe–C–Cu–Ni containing varying levels of MoS2 were developed from elemental powders. Compressive strength, hardness and density

S. Dhanasekaran; R. Gnanamoorthy

2007-01-01

450

Finishing effect of abrasive flow machining on micro slit fabricated by wire-EDM  

Microsoft Academic Search

This experimental research use the method of abrasive flow machining (AFM) to evaluate the characteristics of various levels\\u000a of roughness and finishing of the complex shaped micro slits fabricated by wire electrical discharge machining (Wire-EDM).\\u000a An investigative methodology based on the Taguchi experimental method for the micro slits of biomedicine was developed to\\u000a determine the parameters of AFM, including abrasive

Hsinn-Jyh Tzeng; Biing-Hwa Yan; Rong-Tzong Hsu; Han-Ming Chow

2007-01-01

451

Structural Surface of Mould Softness Abrasive Flow Precision Polishing Machining Method Based on VOF  

Microsoft Academic Search

Aiming to improve the surface roughness of precision mould structural surface in finish machining, a new mould structural surface no-tool precision polishing method based on softness abrasive flow was brought forward. Dynamical model of softness abrasive flow in bound flow oriented to mould structural surface precision machining was established based on liquid-solid two-phase flow coupling theory and a continuous media

Bo Tang; Shiming Ji; Dapeng Tan

2010-01-01

452

Scaling relationships for the abrasion of steel by diamondlike carbon coatings  

Microsoft Academic Search

In previous work we found that the rate of abrasion of steel by metal-containing diamondlike carbon Me-DLC coatings is not constant but decreases significantly during the course of our test. In this work we provide quantitative scaling relationships which show how the time dependence of the abrasion rate of a steel ball by a Me-DLC-coated disk varies with important parameters

Stephen J. Harris; Anita M. Weiner

1998-01-01

453

Creating successful blast furnace refractory systems  

SciTech Connect

Successful lifetimes of the refractories utilized in the blast furnace are dependent on a variety of external factors such as operation, geometry, cooling capability, configuration and arrangement, as well as refractory properties. These external factors, as well as the properties required to withstand the main mechanisms of wear, combine to create the successful refractory system. These significant factors and properties are reviewed with the intention of providing guidelines required for successful refractory performance in the blast furnace.

Dzermejko, A.J. [UCAR Carbon Co., Inc., Columbia, TN (United States)

1995-07-01

454

Blast furnace repairs, relines and modernizations  

Microsoft Academic Search

Bethlehem Steel's Burns Harbor Div. operates two 89,000-cu ft blast furnaces, D and C, built in 1969 and 1972. These furnaces have been in the forefront of blast furnace performance since they were blown-in. To maintain a credible operation throughout the past 25 years their performance has been improved continuously. Production was increased approximately 3%\\/year while fuel rate decreased 1%\\/year.

J. A. Carpenter; D. E Swanson; R. F. Chango

1994-01-01

455

Kinetic energy density and agglomerate abrasion rate during blending of agglomerates into powders.  

PubMed

Problems related to the blending of a cohesive powder with a free flowing bulk powder are frequently encountered in the pharmaceutical industry. The cohesive powder often forms lumps or agglomerates which are not dispersed during the mixing process and are therefore detrimental to blend uniformity. Achieving sufficient blend uniformity requires that the blending conditions are able to break up agglomerates, which is often an abrasion process. This study was based on the assumption that the abrasion rate of agglomerates determines the required blending time. It is shown that the kinetic energy density of the moving powder bed is a relevant parameter which correlates with the abrasion rate of agglomerates. However, aspects related to the strength of agglomerates should also be considered. For this reason the Stokes abrasion number (St(Abr)) has been defined. This parameter describes the ratio between the kinetic energy density of the moving powder bed and the work of fracture of the agglomerate. The St(Abr) number is shown to predict the abrasion potential of agglomerates in the dry-mixing process. It appeared possible to include effects of filler particle size and impeller rotational rate into this concept. A clear relationship between abrasion rate of agglomerates and the value of St(Abr) was demonstrated. PMID:22127372

Willemsz, Tofan A; Hooijmaijers, Ricardo; Rubingh, Carina M; Tran, Thanh N; Frijlink, Henderik W; Vromans, Herman; van der Voort Maarschalk, Kees

2012-01-23

456

An energetic approach to abrasive wear of a martensitic stainless steel  

SciTech Connect

Abrasive wear is the most common type of wear that causes failure of machine elements. Examinations of abraded surfaces revealed presence of embedded particles and grooves elongated along the sliding direction. This indicates that, there are two sequential stages of an abrasion process. In the first stage, asperities on the hard surface and/or hard abrasive grains penetrate into the soft material surface and then in the second stage, they grind the surface in the sliding direction. Therefore, indentation and scratching of an indenter, which can be realized by hardness and scratch tests, can simulate the damage produced on the abraded surface. On the basis of this simulation, an energetic model is proposed for abrasive wear in the present study. In this study, abrasive wear behavior of a martensitic stainless steel is examined by hardness and scratch tests. The results of tests were evaluated to estimate the work done during abrasion and to find out the dimensional wear coefficient according to the model proposed above.

Pamuk, U.; Baydogan, M.; Niluefer, B.; Cimenoglu, H.

2000-04-01

457

Age-related mandible abrasion in the groundhopper Tetrix tenuicornis (Tetrigidae, Orthoptera).  

PubMed

A study was conducted to determine whether the mandibles of the detrito-/bryophagous groundhopper Tetrix tenuicornis are subject to mechanical wear as a result of feeding, as is the case for grasshoppers that feed on silica-rich grasses. Abrasion was evaluated by measuring the length and width of the 3rd incisor and length of the 4th incisor in adults of different ages collected under natural conditions during one season. Although T. tenuicornis and other groundhoppers avoid feeding on grasses, we found that mandible abrasion increased with T. tenuicornis age. Age-related abrasion of the incisors of left and right mandibles was statistically significant in both sexes but the degree of abrasion was greater for females than males, apparently reflecting differences in the frequency and magnitude of feeding. Degree of abrasion also differed between right and left mandibles, probably because of differences in how each mandible is used during food processing. Abrasion of cuticular mandible structures may reduce the effectiveness of food processing late in the season. PMID:24583696

Ku?avová, Kate?ina; Hajduková, Lenka; Ko?árek, Petr

2014-05-01

458

Relationships Between Abrasion Index and Shape Properties of Progressively Abraded Dolerite Railway Ballasts  

NASA Astrophysics Data System (ADS)

Sub-angular-shaped aggregates are used as rail foundation ballasts and must remain sub-angular during their service life time to maintain particle-particle interlocking, in order to ensure the stability of the rail line and prevent accidents by derailment. Here, the screening of dolerite quarry aggregates for use as railway foundation ballasts was investigated by employing simple digital image and chart methods. The average particle size ( d 50), flakiness index (FI), Los Angeles abrasion index (LAAI), sphericity (SPH) and roundness (RND) were determined for two batches of dolerite ballasts from the Rooikraal quarry in Johannesburg and Ngagane quarry in Newcastle. Thirty samples from each of the two batches of ballast were analysed. The ballasts were progressively abraded using a Los Angeles abrasion device and were analysed after each cycle of abrasion. A decrease in d 50 and an increase in FI with increased number of abrasion cycles were observed for both batches of dolerite ballast. The difference in the chart and digital image values of RND and SPH were marginal before abrasion; however, these differences increased with each abrasion cycle. The LAAI, d 50, mean RND and mean SPH correlated significantly and were found to have high regression coefficients. Thus, statistical models are proposed for the non-destructive routine screening of in-place ballasts in order to track marginal changes in aggregate shapes, facilitate ballast replacement programmes and avoid rail line instability.

Okonta, F. N.

2014-07-01

459

Quality of coal for blast furnace injection  

SciTech Connect

CANMET Energy Technology Centre (CETC) has been involved in a research program to evaluate the suitability of various coals for blast furnace injection. The primary objectives of this program are to provide essential information on coal combustion in the blast furnace and to establish proper criteria for evaluating and selecting coals for blast furnace injection. The program comprises three parts. Parts one and two have been completed. To date, the program has encompassed both a theoretical assessment of cooling and coke replacement characteristics of coals using CETC`s computer model and an experimental determination of the combustibility of coals of different ranks and particle sizes as well as the influence of oxygen enrichment on burnout. The experimental part was conducted in CETC`s pilot-scale injection unit that simulates blast furnace blowpipe-tuyere conditions. Part three now being developed will incorporate results of experimental trials into a blast furnace raceway model in order to predict total combustibility of coals at different blast furnace operating conditions. This paper describes CETC`s facility and methodology of work, and presents and discusses results.

Hutny, W.P.; Giroux, L.; MacPhee, J.A.; Price, J.T. [CANMET Energy Technology Centre/Natural Resources Canada, Ottawa, Ontario (Canada)

1996-12-31

460

Neuropathology of explosive blast traumatic brain injury.  

PubMed

During the conflicts of the Global War on Terror, which are Operation Enduring Freedom (OEF) in Afghanistan and Operation Iraqi Freedom (OIF), there have been over a quarter of a million diagnosed cases of traumatic brain injury (TBI). The vast majority are due to explosive blast. Although explosive blast TBI (bTBI) shares many clinical features with closed head TBI (cTBI) and penetrating TBI (pTBI), it has unique features, such as early cerebral edema and prolonged cerebral vasospasm. Evolving work suggests that diffuse axonal injury (DAI) seen following explosive blast exposure is different than DAI from focal impact injury. These unique features support the notion that bTBI is a separate and distinct form of TBI. This review summarizes the current state of knowledge pertaining to bTBI. Areas of discussion are: the physics of explosive blast generation, blast wave interaction with the bony calvarium and brain tissue, gross tissue pathophysiology, regional brain injury, and cellular and molecular mechanisms of explosive blast neurotrauma. PMID:22836523

Magnuson, John; Leonessa, Fabio; Ling, Geoffrey S F

2012-10-01

461

Ultra Safe And Secure Blasting System  

SciTech Connect

The Ultra is a blasting system that is designed for special applications where the risk and consequences of unauthorized demolition or blasting are so great that the use of an extraordinarily safe and secure blasting system is justified. Such a blasting system would be connected and logically welded together through digital code-linking as part of the blasting system set-up and initialization process. The Ultra's security is so robust that it will defeat the people who designed and built the components in any attempt at unauthorized detonation. Anyone attempting to gain unauthorized control of the system by substituting components or tapping into communications lines will be thwarted in their inability to provide encrypted authentication. Authentication occurs through the use of codes that are generated by the system during initialization code-linking and the codes remain unknown to anyone, including the authorized operator. Once code-linked, a closed system has been created. The system requires all components connected as they were during initialization as well as a unique code entered by the operator for function and blasting.

Hart, M M

2009-07-27

462

Gapped BLAST and PSI-BLAST: a new generation of protein database search programs.  

PubMed Central

The BLAST programs are widely used tools for searching protein and DNA databases for sequence similarities. For protein comparisons, a variety of definitional, algorithmic and statistical refinements described here permits the execution time of the BLAST programs to be decreased substantially while enhancing their sensitivity to weak similarities. A new criterion for triggering the extension of word hits, combined with a new heuristic for generating gapped alignments, yields a gapped BLAST program that runs at approximately three times the speed of the original. In addition, a method is introduced for automatically combining statistically significant alignments produced by BLAST into a position-specific score matrix, and searching the database using this matrix. The resulting Position-Specific Iterated BLAST (PSI-BLAST) program runs at approximately the same speed per iteration as gapped BLAST, but in many cases is much more sensitive to weak but biologically relevant sequence similarities. PSI-BLAST is used to uncover several new and interesting members of the BRCT superfamily. PMID:9254694

Altschul, S F; Madden, T L; Schaffer, A A; Zhang, J; Zhang, Z; Miller, W; Lipman, D J

1997-01-01

463

Blast Mitigation by Water Mist, (3) Mitigation of Confined and Unconfined Blasts.  

National Technical Information Service (NTIS)

This is the third in a series of reports focusing on numerical simulations of blasts and blast mitigation. This report uses the models developed in the first two to specifically examine the effect of water mists consisting of sub-50-micron droplets on bla...

D. Schwer, K. Kailasanath

2006-01-01

464

Mechanics of the pad-abrasive-wafer contact in chemical mechanical polishing  

NASA Astrophysics Data System (ADS)

In chemical mechanical polishing (CMP), a rigid wafer is forced on a rough, elastomeric polishing pad, while a slurry containing abrasive particles flows through the interface. The applied pressure on the wafer is carried partially by the 2-body pad-wafer contact (direct contact) and partially by the 3-body contact of pad, wafer and abrasive particles ( particle contact). The fraction of the applied pressure carried by particle contacts is an important factor affecting the material removal rate (MRR) as the majority of the material is removed by the abrasive particles trapped between the pad asperities and the wafer. In this thesis, the contact of a rough, deformable pad and a smooth, rigid wafer in the presence of rigid abrasive particles at the contact interface is investigated by using contact mechanics and finite element (FE) modeling. The interactions between the pad, the wafer and the abrasive particles are modeled at different scales of contact, starting from particle level interactions, and gradually expanding the contact scale to the multi-asperity contact of pad and wafer. The effect of surface forces consisting of van der Waals and electrical double layer forces acting between the wafer and the abrasive particles are also investigated in this work. The wear rate due to each abrasive particle is calculated based on the wafer-abrasive particle contact force, and by considering adhesive and abrasive wear mechanisms. A passivated layer on the wafer surface with a hardness and thickness determined by the chemical effects is modeled, in order to characterize the effect of chemical reactions between slurry and wafer on the MRR. The model provides accurate predictions for the MRR as a function of pad related parameters; pad elastic modulus, pad porosity and pad topography, particle related parameters; particle size and concentration, and slurry related parameters; slurry pH, thickness and hardness of the passivated surface layer of wafer. A good qualitative agreement between the model and the experiments is found for the variation of the MRR with respect to these parameters. Furthermore, closed form equations are derived in order to optimize the CMP parameters for maximizing the material removal efficiency, which is a measure of the ability of pad to transmit the applied pressure on the abrasive particles. The optimization of the CMP parameters described in this thesis may be particularly important for the low-pressure CMP of ultra-low-k (ULK) dielectric materials, where it is difficult to achieve acceptable MRR without compromising the porous structure of ULK materials.

Bozkaya, Dincer

465

30 CFR 77.1910 - Explosives and blasting; general.  

Code of Federal Regulations, 2012 CFR

...the excavation is too shallow to retain blasted material. (f) Where it is impracticable to prepare primers in the blasting area, primers may be prepared on the surface and carried into the shaft in specially constructed, insulated,...

2012-07-01

466

30 CFR 77.1910 - Explosives and blasting; general.  

Code of Federal Regulations, 2011 CFR

...the excavation is too shallow to retain blasted material. (f) Where it is impracticable to prepare primers in the blasting area, primers may be prepared on the surface and carried into the shaft in specially constructed, insulated,...

2011-07-01

467

SCHOLARLY PAPERS Is Construction Blasting Still Abnormally Dangerous?  

E-print Network

has been applied to damages caused by flying debris, e.g., rocks, soil, or other material, being cast Database subject headings: Construction; Blasting; Liability; Negligence; Soil mechanics; Vibration; Subsurface environment. Author keywords: Construction blasting; Liability; Causation; Negligence; Soil

468

3. VIEW OF DUQUESNE'S RAIL LINES AND BLAST FURNACE PLANT ...  

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

3. VIEW OF DUQUESNE'S RAIL LINES AND BLAST FURNACE PLANT LOOKING NORTH. DOROTHY SIX IS THE CLOSEST FURNACE IN THE PHOTOGRAPH. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

469

1. LOOKING EAST AT BLAST FURNACES NO. 3 AND No. ...  

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

1. LOOKING EAST AT BLAST FURNACES NO. 3 AND No. 4 FROM CRAWFORD STREET IN THE CITY OF DUQUESNE. (Martin Stupich) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

470

EXTERIOR VIEW, BLAST FURNACE NO. 3 (JANE FURNACE) CENTER, NO. ...  

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

EXTERIOR VIEW, BLAST FURNACE NO. 3 (JANE FURNACE) CENTER, NO. 3 CAST HOUSE TO THE LEFT, WEST ORE BRIDGE TO THE RIGHT. - Pittsburgh Steel Company, Monessen Works, Blast Furnace No. 3, Donner Avenue, Monessen, Westmoreland County, PA

471

13. SOUTHWEST VIEW OF CAST HOUSE No. 1, BLAST FURNACE ...  

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

13. SOUTHWEST VIEW OF CAST HOUSE No. 1, BLAST FURNACE No. 1, AND HOIST HOUSE No. 1. (Martin Stupich) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

472

VIEW LOOKING NORTHWEST WITH OPENHEARTH TO LEFT WITH BLAST FURNACE ...  

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

VIEW LOOKING NORTHWEST WITH OPEN-HEARTH TO LEFT WITH BLAST FURNACE NO. 2 AND CAST HOUSE TO THE RIGHT. - Pittsburgh Steel Company, Monessen Works, Blast Furnace No. 1 & No. 2, Donner Avenue, Monessen, Westmoreland County, PA

473

58. LOOKING EAST DOROTHY SIX BLAST FURNACE WITH BRICK SHED ...  

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

58. LOOKING EAST DOROTHY SIX BLAST FURNACE WITH BRICK SHED No. 3 IN FOREGROUND ON RIGHT. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

474

56. LOOKING NORTH AT DOROTHY SIX BLAST FURNACE WITH CAST ...  

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

56. LOOKING NORTH AT DOROTHY SIX BLAST FURNACE WITH CAST HOUSE IN FOREGROUND AND DUSTCATCHER AT RIGHT OF FURNACE (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

475

INTERIOR VIEW OF BLAST FURNACE NO. 3 LOOKING EAST, SLAG ...  

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

INTERIOR VIEW OF BLAST FURNACE NO. 3 LOOKING EAST, SLAG RUNNERS & GATES IN FOREGROUND. - Pittsburgh Steel Company, Monessen Works, Blast Furnace No. 3, Donner Avenue, Monessen, Westmoreland County, PA

476

55. GENERAL NORTHEASTERN VIEW OF DOROTHY SIX BLAST FURNACE COMPLEX ...  

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

55. GENERAL NORTHEASTERN VIEW OF DOROTHY SIX BLAST FURNACE COMPLEX WITH LADLE HOUSE AND IRON DESULPHERIZATION BUILDING ON RIGHT. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

477

70. CONTROL PANEL INSIDE OF THE DOROTHY SIX BLAST FURNACE ...  

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

70. CONTROL PANEL INSIDE OF THE DOROTHY SIX BLAST FURNACE STOCKHOUSE LOOKING NORTH. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

478

DETAIL VIEW OF BLAST FURNACE NO. 3 AREA BELOW BUSTLE ...  

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

DETAIL VIEW OF BLAST FURNACE NO. 3 AREA BELOW BUSTLE PIPE, CINDER NOTCH IN CENTER, SLAG RUNNER IN FOREGROUND. - Pittsburgh Steel Company, Monessen Works, Blast Furnace No. 3, Donner Avenue, Monessen, Westmoreland County, PA

479

INTERIOR VIEW LOOKING EAST, BLAST FURNACE NO. 1 CLOSEUP, IRON ...  

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

INTERIOR VIEW LOOKING EAST, BLAST FURNACE NO. 1 CLOSE-UP, IRON NOTCH IN CENTER. - Pittsburgh Steel Company, Monessen Works, Blast Furnace No. 1 & No. 2, Donner Avenue, Monessen, Westmoreland County, PA

480

59. REMAINS OF THE DOROTHY SIX BLAST FURNACE COMPLEX LOOKING ...  

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

59. REMAINS OF THE DOROTHY SIX BLAST FURNACE COMPLEX LOOKING NORTHEAST. THE LADLE HOUSE IS ON THE RIGHT. (Martin Stupich) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

481

7. LOOKING EAST AT HOIST HOUSE No. 1 AND BLAST ...  

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

7. LOOKING EAST AT HOIST HOUSE No. 1 AND BLAST FURNACE No. 1, WITH ORE YARD AND ORE BRIDGES IN FOREGROUND. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

482

68. DETAIL OF COOLING WATER PIPES FOR DOROTHY SIX BLAST ...  

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

68. DETAIL OF COOLING WATER PIPES FOR DOROTHY SIX BLAST FURNACE. INTERIOR OF CAST HOUSE LOOKING NORTH. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

483

30 CFR 56.6605 - Isolation of blasting circuits.  

Code of Federal Regulations, 2013 CFR

...STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Extraneous Electricity § 56.6605 Isolation of blasting circuits. Lead...tracks, and shall be protected from sources of stray or static electricity. Blasting circuits shall be protected from any...

2013-07-01

484

30 CFR 57.6605 - Isolation of blasting circuits.  

Code of Federal Regulations, 2013 CFR

...STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Extraneous Electricity-Surface and Underground § 57.6605 Isolation of blasting...tracks, and shall be protected from sources of stray or static electricity. Blasting circuits shall be protected from any...

2013-07-01

485

Use of probabilistic methods in evaluating blast performance of structures  

E-print Network

The social and political climate of the modern world has lead to increased concern over the ability of engineered structures to resist blast events which may be incurred during terrorist attacks. While blast resistance ...

Gillis, Andrew Nicholas

2011-01-01

486

6. Photocopy of a drawing of the lead blast furnace ...  

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

6. Photocopy of a drawing of the lead blast furnace from J.L. Bray, The Principles of Metallurgy, Ginn & Co. New York, 1929. - International Smelting & Refining Company, Tooele Smelter, Blast Furnace Building, State Route 178, Tooele, Tooele County, UT

487

31. VIEW OF TRIPPER CAR ON TOP OF BLAST FURNACE ...  

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

31. VIEW OF TRIPPER CAR ON TOP OF BLAST FURNACE STOCKING TRESTLE LOOKING EAST. (Martin Stupich) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

488

EXPERIMENTAL STUDIES OF MITIGATION MATERIALS FOR BLAST INDUCED TBI  

E-print Network

The objective of this experimental study is to compare the effects of various materials obstructing the flow of a blast wave and the ability of the given material to reduce the damage caused by the blast. Several methods ...

Young, Laurence Retman

489

Blast overpressure relief using air vacated buffer medium  

E-print Network

Blast waves generated by intense explosions cause damage to structures and human injury. In this thesis, a strategy is investigated for relief of blast overpressure resulting from explosions in air. The strategy is based ...

Avasarala, Srikanti Rupa

2009-01-01

490

Computational modeling of blast-induced traumatic brain injury  

E-print Network

Blast-induced TBI has gained prominence in recent years due to the conflicts in Iraq and Afghanistan, yet little is known about the mechanical effects of blasts on the human head; no injury thresholds have been established ...

Nyein, Michelle K. (Michelle Kyaw)

2010-01-01

491

30 CFR 816.64 - Use of explosives: Blasting schedule.  

...and reasonable in order to protect the public health and safety or welfare. (2) All blasting shall be conducted between sunrise and sunset, unless nighttime blasting is approved by the regulatory authority based upon a showing by the operator...

2014-07-01

492

29 CFR 1926.909 - Firing the blast.  

...Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Blasting...through the danger zone so as to stop traffic during blasting operations....

2014-07-01

493

49 CFR 587.16 - Adhesive bonding procedure.  

Code of Federal Regulations, 2010 CFR

...deposits. The cleaned surfaces are abraded using 120 grit abrasive paper. Metallic/silicon carbide abrasive paper is not to be used. The surfaces are thoroughly abraded and the abrasive paper changed regularly during the process to...

2010-10-01

494

Copper staves in the blast furnace  

SciTech Connect

Operational data for stave cooling systems for two German blast furnaces show good correlation with predicted thermal results. Copper staves have been installed in blast furnaces in the zones exposed to the highest thermal loads. The good operational results achieved confirm the choice of copper staves in the areas of maximum heat load. Both temperature measurements and predictions establish that the MAN GHH copper staves do not experience large temperature fluctuations and that the hot face temperatures will be below 250 F. This suggests that the copper staves maintain a more stable accretion layer than the cast iron staves. Contrary to initial expectations, heat flux to the copper staves is 50% lower than that to cast iron staves. The more stable accretion layer acts as an excellent insulator for the stave and greatly reduces the number of times the hot face of the stave is exposed to the blast furnace process and should result in a more stable furnace operation. In the future, it may be unnecessary to use high quality, expensive refractories in front of copper staves because of the highly stable accretion layer that appears to rapidly form due to the lower operating temperature of the staves. There is a balance of application regions for cast iron and copper staves that minimizes the capital cost of a blast furnace reline and provides an integrated cooling system with multiple campaign life potential. Cast iron staves are proven cooling elements that are capable of multiple campaign life in areas of the blast furnace which do not experience extreme heat loads. Copper staves are proving to be an effective and reliable blast furnace cooling element that are subject to virtually no wear and are projected to have a longer campaign service life in the areas of highest thermal load in the blast furnace.

Helenbrook, R.G. [ATSI, Inc., Amherst, NY (United States); Kowalski, W. [Thyssen Stahl AG, Duisburg (Germany); Grosspietsch, K.H. [Preussag Stahl AG, Saltzgitter (Germany); Hille, H. [MAN GHH AG, Oberhausen (Germany)

1996-08-01

495

Failure of a novel silicone-polyurethane copolymer (Optim(TM)) to prevent implantable cardioverter-defibrillator lead insulation abrasions  

PubMed Central

Aim The purpose of this study was to determine if Optim™, a unique copolymer of silicone and polyurethane, protects Riata ST Optim and Durata implantable cardioverter-defibrillator (ICD) leads (SJM, St Jude Medical Inc., Sylmar, CA, USA) from abrasions that cause lead failure. Methods and results We searched the US Food and Drug Administration's (FDA's) Manufacturers and User Device Experience (MAUDE) database on 13 April 2012 using the simple search terms ‘Riata ST Optim™ abrasion analysis’ and ‘Durata abrasion analysis’. Lead implant time was estimated by subtracting 3 months from the reported lead age. The MAUDE search returned 15 reports for Riata ST Optim™ and 37 reports for Durata leads, which were submitted by SJM based on its analyses of returned leads for clinical events that occurred between December 2007 and January 2012. Riata ST Optim™ leads had been implanted 29.1 ± 11.7 months. Eight of 15 leads had can abrasions and three abrasions were caused by friction with another device, most likely another lead. Four of these abrasions resulted in high-voltage failures and one death. One failure was caused by an internal insulation defect. Durata leads had been implanted 22.2 ± 10.6 months. Twelve Durata leads had can abrasions, and six leads had abrasions caused by friction with another device. Of these 18 can and other device abrasions, 13 (72%) had electrical abnormalities. Low impedances identified three internal insulation abrasions. Conclusions Riata ST Optim™ and Durata ICD leads have failed due to insulation abrasions. Optim™ did not prevent these abrasions, which developed ?4 years after implant. Studies are needed to determine the incidence of these failures and their clinical implications. PMID:22915789

Hauser, Robert G.; Abdelhadi, Raed H.; McGriff, Deepa M.; Kallinen Retel, Linda

2013-01-01

496

The design, implementation, and evaluation of mpiBLAST  

Microsoft Academic Search

mpiBLAST is an open-source parallelization of BLAST that achieves superlinear speed-up by segmenting a BLAST database and then having each node in a computational cluster search a unique portion of the database. Database segmentation permits each node to search a smaller portion of the database, eliminating disk I\\/O and vastly improving BLAST performance. Because database segmentation does not create heavy

Aaron E. Darling; Lucas Carey; Wu-chun Feng

2003-01-01

497

Mesh considerations for finite element blast modelling in biomechanics  

Microsoft Academic Search

Finite element (FE) modelling is a popular tool for studying human body response to blast exposure. However, blast modelling is a complex problem owing to more numerous fluid–structure interactions (FSIs) and the high–frequency loading that accompanies blast exposures. This study investigates FE mesh design for blast modelling using a sphere in a closed-ended shock tube meshed with varying element sizes

Matthew B. Panzer; Barry S. Myers; Cameron R. Bass

2011-01-01

498

The Mars Environmental Compatibility Assessment (MECA) Abrasion Tool  

NASA Technical Reports Server (NTRS)

The Mars Environmental Compatibility Assessment (MECA) experiment, an instrument suite to be flown on Mars Surveyor 2001, will include a tool for doing simple mineralogical scratch and streak tests on particles from the Martian regolith. The Abrasion Tool will be applied to particles that adhere themselves to highly polished substrates of various hardnesses. Granular soil components will be subjected to a compressive force of about 3 N using a leaf spring. The spring will be applied with a paraffin actuator capable of a 0.76 mm throw to achieve a maximum displacement of about 7.5 mm at the tip of the tool. The pressure per grain will be dependent on the grain size, the number of grains that adhere to the substrate and the number of grains in compression. The pressure per particle is expected to be on the order of 100 MPa - 1 GPa. The MECA sample wheel containing the substrates will be rotated after the particles are placed in compression to produce scratches or pits. A primary goal of the Abrasion Tool is to identify quartz (Mohs' hardness = 7) using substrates of varying hardnesses. Quartz is considered hazardous to future human explorers of Mars because it can cause silicosis of the lungs if it is of respirable size. It is also hazardous to machinery, structures, and space suits because of its ability to abrade and scratch surfaces. Since large quantities of minerals harder than quartz are not expected, any scratches produced on polished quartz substrates might be reasonably attributed to quartz particles, although there may be minerals such as impact metamorphic diamond in the soils. Careful calibration of the tool will be necessary to ensure that grains are not overloaded; for example, a steel ball pressed into glass will produce a Hertzian fracture, even though it is softer than glass. Other minerals, such as magnetite (Mohs' hardness = 6.5) have been shown to scratch glass ceramics such as Zerodur (Mohs' hardness = 6.5). Thus, minerals can be differentiated: note that regardless of the mineral species, if any particle is harder than 6.5 it will certainly be an interesting discovery for both planetary geology and human exploration concerns. The scratches will be identified using the 6X optical microscope and profiled with the atomic force microscope included in the MECA instrument suite. Analysis of the scratch morphology will yield evidence concerning the shape of the particle responsible for producing each scratch. For example, angular grains should leave vertical cracks with microconchoidal lateral chipping, while rounded grains might leave chatter marks, or nested partial Hertzian cracks. Particle shape can thus be inferred from these indentation modes, as well as material hardness. In addition, particle size information may also be available if pits caused by rolling particles can be identified. Converse to scratching, the minerals may be crushed at their contact points, and be smeared onto the target substrates to leave what geologists refer to as "streaks". These are cold-welded trails of mineral material that have structure and color indicative of mineral composition. The AFM will determine the morphology of these streaks, while the microscope will ascertain the color. On the harder substrates, we might expect streaking to dominate; on the softer substrates, scratching may dominate. Progressions of material interactions across the substrate selection will be a valuable source of data for mineral discrimination. It should also be noted that many minerals have coatings (such as iron oxides), and these will have to be differentiated from the host mineral grains; laboratory tests will establish the effects of such coatings on the scratch results. Finally, we note that the microscope will provide corroborative data regarding likely mineral species by grain shapes, fracture patterns, surface textures, color, and UV fluorescence reactions. Additional information is contained in the original extended abstract.

Kuhlman, K. R.; Anderson, M. S.; Hinde, B. D.; Hecht, M. H.; Pike, W. T.; Marshall, J. R.; Meloy, T. P.

1999-01-01

499

The Mars Environmental Compatibility Assessment MECA Abrasion Tool  

NASA Technical Reports Server (NTRS)

The Mars Environmental Compatibility Assessment (MECA) experiment, an instrument suite to be flown on Mars Surveyor 2001, will include a tool for doing simple mineralogical scratch and streak tests on particles from the Martian regolith. The Abrasion Tool will be applied to particles that adhere to highly polished substrates of various hardnesses. Granular soil components will be subjected to a compressive force of about 3 N using a leaf spring. The spring will be applied with a paraffin actuator capable of a 0.76 mm throw to achieve a maximum displacement of about 7.5 mm at the tip of the tool. The pressure per grain will be dependent on the grain size, the number of grains that adhere to the substrate and the number of grains in compression. The pressure per particle is expected to be on the order of 100 MPa - 1 GPa. The MECA sample wheel containing the substrates will be rotated after the particles are placed in compression to produce scratches or pits. A primary goal of the Abrasion Tool is to identify quartz (Mohs' hardness = 7) using substrates of varying hardnesses. Quartz is considered hazardous to future human explorers of Mars because it can cause silicosis of the lungs if it is of respirable size. It is also hazardous to machinery, structures, and space suits because of its ability to abrade and scratch surfaces. Since large quantities of minerals harder than quartz are not expected, any scratches produced on polished quartz substrates might be reasonably attributed to quartz particles, although there may be minerals such as impact metamorphic diamond in the soils. Careful calibration of the tool will be necessary to ensure that grains are not overloaded; for example, a steel ball pressed into glass will produce a Hertzian fracture, even though it is softer than glass. Other minerals, such as magnetite (Mohs'hardness = 6.5) have been shown to scratch glass ceramics such as Zerodur (Mohs' hardness = 6.5). Thus, minerals can be differentiated: note that regardless of the mineral species, if any particle is harder than 6.5 it will certainly be an interesting discovery for both planetary geology and human exploration concerns. The scratches will be identified using the 6X optical microscope and profiled with the atomic force microscope included in the MECA instrument suite. Analysis of the scratch morphology will yield evidence concerning the shape of the particle responsible for producing each scratch. For example, angular grains should leave vertical cracks with microconchoidal lateral chipping, while rounded grains might leave chattermarks, or nested partial Hertzian cracks. Particle shape can thus be inferred from these indentation modes, as well as material hardness. In addition, particle size information may also be available if pits caused by rolling particles can be identified. Converse to scratching, the minerals may be crushed at their contact points, and be smeared onto the target substrates to leave what geologists refer to as "streaks". These are coldwelded trails of mineral material that have structure and color indicative of mineral composition. The AFM will determine the morphology of these streaks, while the microscope will ascertain the color. On the harder substrates, we might expect streaking to dominate; on the softer substrates, scratching may dominate. Progressions of material interactions across the substrate selection will be a valuable source of data for mineral discrimination. It should also be noted that many minerals have coatings (such as iron oxides), and these will have to be differentiated from the host mineral grains; laboratory tests will establish the effects of such coatings on the scratch results. Finally, we note that the microscope will provide corroborative data regarding likely mineral species by grain shapes, fracture patterns, surface textures, colr, and UV fluorescence reactions.

Kuhlman, K. R.; Anderson, M. S.; Hinde, B. D.; Hecht, M. H.; Pike, W. T.; Marshall, J.; Meloy, T. P.; Cobbly, T.

1999-01-01

500

15. NORTHERN VIEW OF THE REMAINS OF BLAST FURNACE No. ...  

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

15. NORTHERN VIEW OF THE REMAINS OF BLAST FURNACE No. 2 IN LOWER CENTER OF PHOTO AT THE BASE OF HOT BLAST STOVES. HOIST HOUSE No. 2 IS ON THE LEFT. (Martin Stupich) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA