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1

Detecting Residues On Grit-Blasted Surfaces  

NASA Technical Reports Server (NTRS)

Addition of fluorescent or iridescent material to plastic grit particles proposed for detection of grit residues after grit-blast cleaning. Residual films visible by observing grit-blasted surfaces under infrared or ultraviolet light. Plastic grit contains fluorescent or iridescent additive in core and coating. Wherever grit material becomes embedded, additive makes it visible under infrared or ultraviolet light. Applicable to other grit materials, for example fluorescent or iridescent materials added to particles of glass, silicon carbide, aluminum oxide, or zirconium silicate.

Novak, H. L.; Zook, L. M.

1989-01-01

2

SURFACE PREPARATION OF STEEL SUBSTRATES USING GRIT-BLASTING  

SciTech Connect

The primary purpose of grit blasting for thermal spray applications is to ensure a strong mechanical bond between the substrate and the coating by the enhanced roughening of the substrate material. This study presents statistically designed experiments that were accomplished to investigate the effect of abrasives on roughness for A36/1020 steel. The experiments were conducted using a Box statistical design of experiment (SDE) approach. Three grit blasting parameters and their effect on the resultant substrate roughness were investigated. These include blast media, blast pressure, and working distance. The substrates were characterized for roughness using surface profilometry. These attributes were correlated with the changes in operating parameters. Twin-Wire Electric Arc (TWEA) coatings of aluminum and zinc/aluminum were deposited on the grit-blasted substrates. These coatings were then tested for bond strength. Bond strength studies were conducted utilizing a portable adhesion tester following ASTM standard D4541.

Donna Post Guillen; D. J. Varacalle, Jr.; D. Deason; W. Rhodaberger; E. Sampson

2005-05-01

3

Effect of grit-blasting on substrate roughness and coating adhesion  

NASA Astrophysics Data System (ADS)

Statistically designed experiments were performed to compare the surface roughness produced by grit blasting A36/1020 steel using different abrasives. Grit blast media, blast pressure, and working distance were varied using a Box-type statistical design of experiment (SDE) approach. The surface textures produced by four metal grits (HG16, HG18, HG25, and HG40) and three conventional grits (copper slag, coal slag, and chilled iron) were compared. Substrate roughness was measured using surface profilometry and correlated with operating parameters. The HG16 grit produced the highest surface roughness of all the grits tested. Aluminum and zinc-aluminum coatings were deposited on the grit-blasted substrates using the twin-wire electric are (TWEA) process. Bond strength of the coatings was measured with a portable adhesion tester in accordance with ASTM standard D 4541. The coatings on substrates roughened with steel grit exhibit superior bond strength to those prepared with conventional grit. For aluminum coatings sprayed onto surfaces prepared with the HG16 grit, the bond strength was most influenced by current, spray distance, and spray gun pressure (in that order). The highest bond strength for the zinc-aluminum coatings was attained on surfaces prepared using the metal grits.

Varacalle, Dominic J.; Guillen, Donna Post; Deason, Douglas M.; Rhodaberger, William; Sampson, Elliott

2006-09-01

4

Biology of grit-blasted titanium alloy implants.  

PubMed

This study describes the biologic integration of grit-blasted titanium alloy (Ti-6A1-4V) implants that were press fit into the distal femoral canal of young adult rabbits and evaluated by histologic, histomorphometric, and biomechanical methods. Polished and aluminum oxide grit-blasted (4.2 +/- 0.7 microns surface roughness) solid implants were compared with titanium fibermetal implants. Nondecalcified cross sections were studied by histology, histomorphometry, and electron microscopy in the backscatter mode at 3, 6, and 12 weeks after implantation. Pullout strength was measured at 12 weeks. Data were analyzed by analysis of variance and post-hoc Student-Newman-Keuls and Scheffe's tests. The blasted implants had significantly more bone intimately in contact with the implant surface (31%) than the fibermetal (17%), or solid polished implants (15%). By 3 weeks, woven bone had formed directly on the surface of the blasted implants, whereas there was a discrete space between woven bone and the other implants. Active remodeling of bone was shown by fluorochrome uptake at the surface of the blasted implants at 12 weeks after implantation. The strength of fixation of blasted and fiber-metal implants was significantly greater than polished implants at 12 weeks after implantation. Direct attachment of newly formed bone onto the blasted implant surface was confirmed by backscatter electron microscopy. The results of this study indicate that grit-blasted titanium surfaces provide an excellent surface for bone implant integration. PMID:7554621

Goldberg, V M; Stevenson, S; Feighan, J; Davy, D

1995-10-01

5

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

6

SHOT PEENING AND GRIT BLASTING - EFFECTS ON SURFACE INTEGRITY  

Microsoft Academic Search

This paper describes influence of factors such as particle size (0.55-2.2 mm), particle velocity (15-35 mls) and work hardness on surface integrity. Hardness, residual stress and crystal transformation of areas affected by shot peening or grit blasting are examined. In order to clarify the influences of those factors on the surface integrity, a medium carbon steel (C:0.45%, 180HV) and an

K. Toshal; J. Lu; B. Guelorget; E. Nagashima

7

Diffuse reflectance FTIR of stains on grit blasted metals  

SciTech Connect

Diffuse reflectance mid-infrared Fourier transform (DRIFT) spectroscopy has been applied to the detection of oil contamination on grit-blasted metals. The object of this application is to detect and discriminate between silicone and hydrocarbon oil contamination at levels approaching 10 mg/m{sup 2}. A portable FTIR spectrometer with dedicated diffuse reflectance optics was developed for this purpose. Using translation devices positioned by instructions from the spectrometer operating system, images of macroscopic substrates were produced with millimeter spatial resolution. The pixels that comprise an image are each a full mid-infrared spectrum with excellent signal-to-noise, each determined as individual files and uniquely saved to disc. Reduced spectra amplitudes, based on peak height, area, or other chemometric techniques, mapped as a function of the spatial coordinates of the pixel are used to display the image. This paper demonstrates the application of the technique to the analysis of stains on grit-blasted metals, including the calibration of the method, the inspection of substrates, and the migration of oil contamination.

Powell, G.L.; Hallman, R.L. Jr.; Cox, R.L. [Oak Ridge Centers for Manufacturing Technologies, TN (United States)

1997-08-09

8

Comparative Pulmonary Toxicity of 6 Abrasive Blasting Agents  

Microsoft Academic Search

Inhalation of silica dust is associated with pulmonary fibrosis. Therefore, substitute abrasive materials have been suggested for use in abrasive blasting operations. To date, toxicological evalua- tion of most substitute abrasives has been incomplete. Therefore, the objective of this study was to compare the pulmonary toxicity of a set of substitute abrasives (garnet, staurolite, coal slag, spec- ular hematite, and

A. F. Hubbs; N. S. Minhas; W. Jones; M. Greskevitch; L. A. Battelli; D. W. Porter; W. T. Goldsmith; D. Frazer; D. P. Landsittel; J. Y. C. Ma; M. Barger; K. Hill; D. Schwegler-Berry; V. A. Robinson; V. Castranova

2001-01-01

9

Surface impurity removal from DIII-D graphite tiles by boron carbide grit blasting  

SciTech Connect

During the latter half of 1992, the DIII-D tokamak at General Atomics (GA) underwent several modifications of its interior. One of the major tasks involved the removal of accumulated metallic impurities from the surface of the graphite tiles used to line the plasma facing surfaces inside of the tokamak. Approximately 1500 graphite tiles and 100 boron nitride tiles from the tokamak were cleaned to remove the metallic impurities. The cleaning process consisted of several steps: the removed graphite tiles were permanently marked, surface blasted using boron carbide (B{sub 4}C) grit media (approximately 37 {mu}m. diam.), ultrasonically cleaned in ethanol to remove loose dust, and outgassed at 1000{degrees}C. Tests were done using, graphite samples and different grit blaster settings to determine the optimum propellant and abrasive media pressures to remove a graphite layer approximately 40-50 {mu}m deep and yet produce a reasonably smooth finish. EDX measurements revealed that the blasting technique reduced the surface Ni, Cr, and Fe impurity levels to those of virgin graphite. In addition to the surface impurity removal, tritium monitoring was performed throughout the cleaning process. A bubbler system was set up to monitor the tritium level in the exhaust gas from the grit blaster unit. Surface wipes were also performed on over 10% of the tiles. Typical surface tritium concentrations of the tiles were reduced from about 500 dpm/100 cm{sup 2} to less than 80 dpm/100 cm{sup 2} following the cleaning. This tile conditioning, and the installation of additional graphite tiles to cover a high fraction of the metallic plasma facing surfaces, has substantially reduced metallic impurities in the plasma discharges which has allowed rapid recovery from a seven-month machine opening and regimes of enhanced plasma energy confinement to be more readily obtained. Safety issues concerning blaster operator exposure to carcinogenic metals and radioactive tritium will also be addressed.

Lee, R.L.; Hollerbach, M.A.; Holtrop, K.L.; Kellman, A.G.; Taylor, P.L.; West, W.P.

1993-11-01

10

Modelling and evaluation of the micro abrasive blasting process  

Microsoft Academic Search

Micro abrasive blasting (MAB) is becoming an important machining technique for the cost effective fabrication of micro devices. The material removal process is based on the erosion of a mask-protected brittle substrate by an abrasive-laden air jet. To exploit the potentials of this technique for applications of industrial interest, the blasting process has to become more efficient and better predictable.

M. Achtsnick; P. F. Geelhoed; A. M. Hoogstrate; B. Karpuschewski

2005-01-01

11

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

12

The removal of Al 2O 3 particles from grit-blasted titanium implant surfaces: Effects on biocompatibility, osseointegration and interface strength in vivo  

Microsoft Academic Search

For the improvement of surface roughness and mechanical interlocking with bone, titanium prostheses are grit-blasted with Al2O3 particles during manufacturing. Dislocated Al2O3 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

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

2010-01-01

13

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

14

COMPARATIVE ANALYSIS OF ABRASIVE FOR SHOT BLASTING STEEL STRUCTURE  

Microsoft Academic Search

It is analyzed comparatively t hat t he sort , hardness , microstructure , particle shape , size distribution , macrostructure ,density of an abrasive for shot blasting steel structures during t heir coating and anticorrosion , i1e. t he pretreat ment of steel1A simple met hod of judging t he qualit y of abrasive and t he principles of

Liu Ruwei Li Shengli

15

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

16

Airborne exposure to heavy metals and total particulate during abrasive blasting using copper slag abrasive.  

PubMed

This research investigates occupational exposure to metal and total particulate aerosols during abrasive blasting operations using one substitute abrasive, copper slag. Airborne exposures to metal (As, Be, Pb, Cr, Cd, V, and Ti) and total particulate aerosols from two copper slag sources are evaluated by the collection and analysis of personal breathing zone samples during abrasive blasting operations in both indoor and outdoor settings. Results from this research indicate that abrasive blasting operations using copper slag abrasive can generate, in a relatively short time, total particulate, lead, arsenic, and chromium exposures that exceed permissible exposure limits (PELs) set by the Occupational Safety and Health Administration (OSHA). Results also show statistically significant differences in exposure concentrations between slag sources. A correlation between total particulate concentrations and metal concentrations is indicated in both slag sources and in both indoor and outdoor settings. Results of this research allow occupational health and safety professionals to make a more informed determination of the degree of health risk posed to workers during abrasive blasting operations using commercially obtained copper slag abrasive. PMID:12049434

Stephenson, Dale; Spear, Terry; Seymour, Marie; Cashell, Lori

2002-06-01

17

Demonstration experience with an abrasive blasting technique for decontaminating concrete pads  

Microsoft Academic Search

A demonstration was performed for decontaminating a radioactivity contaminated concrete pad with a portable abrasive blasting system. The system utilizes a rotating blast wheel that scours the concrete surface with metal abrasive. The metal abrasive, pulverized concrete dust, and contaminants rebound into a separator chamber. The reusable metal abrasive is recycled, and the pulverized media are removed to an integral

J. S. Devgun; R. R. Land; R. W. Doane

1990-01-01

18

Nondestructive thermoelectric evaluation of the grit blasting induced effects in metallic biomaterials  

NASA Astrophysics Data System (ADS)

Grit blasting is a surface treatment process widely used to enhance mechanical fixation of the implants through increasing their roughness. Test samples of two metallic biomaterial alloys such 316LVM and Ti6Al4V were blasted by projecting Al2O3 and ZrO2 particles which yield a coarse and a fine rough surface. Then, the blasted samples were thermally treated before and after partial stress relaxation and measured by non-destructive thermoelectric techniques (NDTT), the non-contacting and contacting thermoelectric power (TEP) measurements respectively. It has been found that the TEP measurements are associated directly with the subtle material variations such as cold work and compressive residual stresses due to plastic deformation produced by grit blasting. The TEP measurements clearly demonstrate that the non-contact NDTT technique is very sensitive to the reverse transformation of the ?'-martensite (blasted 316LVM) and the expected relaxation of compressive residual stresses with increasing the severity of the thermal treatment (blasted 316LVM and Ti-6Al-4V), while the contact NDTT results are closely related to grain size refinement and work hardening.

Carreon, H.; Ruiz, A.; Barriuso, S.; González-Carrasco, J. L.; Caballero, F. G.; Lieblich, M.

2013-01-01

19

Surface Modification of Ti Dental Implants by Grit-Blasting and Micro-Arc Oxidation  

Microsoft Academic Search

The osseointegration capability of titanium implants is related to their chemical composition and surface roughness. The combination of grit-blasting and micro-arc oxidation had been used to produce the improved implant surfaces. The ceramic particles were projected to titanium implants at high velocity to get high surface roughness. Then the surface of implants was modified by micro-arc oxidation treatment. A porous

Yeon-Wook Kim

2010-01-01

20

Shot peening, grit blasting make pipe steels more resistant to stress-corrosion cracking  

Microsoft Academic Search

Shot peening or grit blasting to one of several controlled conditions is an effective means of increasing the resistance of pipeline steels to stress-corrosion cracking (SCC). Though the principal benefit is to increase the threshold stress for SCC, mill-scale removal and a good coating anchor pattern provide added benefits. Five principal factors influence the initiation and growth rate of stress-corrosion

T. J. Barlo; R. R. Fessler

1981-01-01

21

Control technology for crystalline silica exposures in construction: wet abrasive blasting.  

PubMed

This study was designed to document the effect that wet abrasive blasting has on reducing worker exposure to crystalline silica, which has been associated with silicosis and premature death. In this study, worker exposure to respirable crystalline silica was monitored during wet abrasive blasting on the exterior walls of a parking garage to remove surface concrete and expose the underlying aggregate. In this process a wet sand mix comprised of 80% dry sand and 20% water was used. Sampling and analysis revealed that the geometric mean respirable quartz concentration was 0.2 mg/m(3) for workers conducting abrasive blasting and 0.06 mg/m(3) for helpers. When abrasive blasting was conducted in areas that apparently had reduced natural ventilation, dust exposures appeared to increase. When compared with other published data, this case study suggests that wet abrasive blasting causes less exposure to crystalline silica than dry abrasive blasting. PMID:15204868

Golla, Vijay; Heitbrink, William

2004-03-01

22

Bioceramic inlays do not improve mechanical incorporation of grit-blasted titanium stems in the proximal sheep femur.  

PubMed

The aim of the present study was to determine, if bioactive glass (BG) surface inlays improve osseointegration of titanium implants in the proximal femur of adult sheep. In simulation of uncemented primary stems (nine animals), only the proximal part of the implants was grit-blasted and three surface slots of the grit-blasted region were filled with sintered BG microspheres. Primary stems were implanted using press-fit technique. In revision stem simulation (eight animals), grit-blasting was extended over the whole implant and seven perforating holes of the stem were filled by sintered BG granules. Revision stems were implanted with a mixture of autogenous bone graft and BG granules. Comparison with solid partially or fully grit-blasted control stems implanted in the contralateral femurs was performed in the primary and revision stem experiments at 12 and 25 weeks, respectively. Implant incorporation was evaluated by torsional failure testing and histomorphometry. Only one-third of the primary stems anchored mechanically to bone. The revision stems incorporated better and the BG inlays of the revision stems showed ingrowth of new bone. However, there were no significant differences in the torsional failure loads between the stems with BG inlays and the control stems. In conclusion, surface BG inlays gave no measurable advantage in mechanical incorporation of grit-blasted titanium implants. Overall, the proximal sheep femur, characterized by minimal amount of cancellous bone and the presence of adipocytic bone marrow, seemed to present compromised bone healing conditions. PMID:19437438

Keränen, Pauli; Koort, Jyri; Itälä, Ari; Ylänen, Heimo; Dalstra, Michel; Hupa, Mikko; Kommonen, Bertel; Aro, Hannu T

2010-03-15

23

Lead, chromium, and cadmium exposure during abrasive blasting.  

PubMed

An evaluation of lead, cadmium, and chromium exposure was conducted during abrasive blasting of a steel bridge to remove paint in preparation for repainting. Airborne lead concentrations were measured at several locations inside the containment structure, as well as near the workers' breathing zones. Airborne cadmium and chromium were also measured in the containment area. Blood lead levels were monitored in each worker. Airborne lead and cadmium levels in containment exceeded the Occupational Safety and Health Administration's permissible exposure limits by factors of 219 and 3.1, respectively. The use of supplied air-blasting helmets will not effectively reduce workers' lead exposure to the permissible exposure limits when airborne levels are as high as were measured in this study. Studies are needed to evaluate additional engineering controls and alternative paint removal methods. Evaluation of workers' exposure to lead and other hazardous metals is needed for projects involving abrasive blasting. Medical surveillance for cadmium and lead may be necessary for similar projects. PMID:8638970

Conroy, L M; Menezes-Lindsay, R M; Sullivan, P M; Cali, S; Forst, L

1996-01-01

24

Lead, chromium, and cadmium emission factors during abrasive blasting operations by bridge painters.  

PubMed

Work space airborne concentrations of lead, chromium, and cadmium were measured during abrasive blasting by bridge painters for the determination of emission rates. The operation used compressed air to blast steel grit at steel or metal surfaces, removing lead-based paint. It was enclosed with plastic tarpaulins to prevent the release of lead- and chromium-laden dust. Consequently, workers were at increased risk from exposure by inhalation or ingestion. Area samples were collected in 13 contained work areas on a 4-leaf bridge and adjacent viaduct while blasting was performed. Enclosure volume and exhaust air flow rate were measured for each containment area. Work space airborne concentrations ranged from 196-31,410 micrograms/m3 for lead, 1-657 micrograms/m3 for chromium, and 1-19 micrograms/m3 for cadmium. Mass balance models were used to calculate emission rates and emission factors using the measured area concentrations. Average emission factors on the bridge were 20,400 mg/m2 for lead, 75 mg/m2 for chromium, and 16 mg/m2 for cadmium; and on the viaduct were 8790 mg/m2 for lead, 568 mg/m2 for chromium, and 2.0 mg/m2 for cadmium. These values were validated using estimates of total paint volume and composition on the structure and total waste generation. All estimates were within 50% of each other except chromium estimates for the bridge. The emission factors allow prediction of work space airborne concentrations during similar operations and are a first step in the design and implementation of control measures. PMID:7717270

Conroy, L M; Lindsay, R M; Sullivan, P M

1995-03-01

25

Significance of the contacting and no contacting thermoelectric power measurements applied to grit blasted medical Ti6Al4V.  

PubMed

Grit blasting is a surface plastic deformation technique aimed to increase the surface area available for bone/implant apposition, which contributes to improve fixation and mechanical stability of Ti-6Al-4V implants. Besides roughening, grit blasting also causes surface contamination with embedded grit particles and subtle subsurface microstructural changes that, although does not challenge their biocompatibility, might influence other surface dominated properties like corrosion and ion release. Additional benefits are expected due to the induced compressive residual stresses, hence enhancing fatigue strength. The net effect depends on the type of particles used for blasting, but also on the amount of the subsurface cold work associated to the severe surface plastic deformation. In this work we study the potential of the non-contacting and contacting thermoelectric power (TEP) measurements in the analysis of the global changes induced in the Ti6Al4V when blasting the alloy with Al2O3 or ZrO2 particles, which yields a coarse and a fine rough surface, respectively. To reveal the effect of residual stresses, a set of specimens were thermally treated. The study proves that the non-contacting technique is more sensitive to the presence of residual stresses, whereas the contact technique is strongly influenced by the grain size refinements, work hardening and changes in solute. PMID:23827590

Carreon, H; Barriuso, S; Lieblich, M; González-Carrasco, J L; Jimenez, J A; Caballero, F G

2013-04-01

26

Abrasive micro-blasting to improve surface integrity of electrical discharge machined WC–Co composite  

Microsoft Academic Search

This study investigates the improvement of surface integrity of wire electrical discharge machined (EDM) WC–Co composite by abrasive micro-blasting. The thermally damaged recast layer generated by EDM has craters, cracks, and bubbles, which deteriorate the surface mechanical properties. The micro-blasting, using 6–12 and 4–20?m size SiC abrasive, enables the removal of the recast layer and is suitable for micro mechanical

Jun Qu; Albert J. Shih; Ronald O. Scattergood; Jie Luo

2005-01-01

27

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

28

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

29

Recycling of paint-contaminated grit.  

PubMed

The impact on the environment of using paint-contaminated grit (PCG) as a partial or full replacement for sand in Portland cement mortar and asphalt concrete mixtures was investigated. The grit waste material originated from abrasive blasting of offshore steel structures. There is a major environmental concern regarding the safe disposal of the spent blasting abrasives that contain paint chips or paint particles and other debris removed from the surface of the steel structures. This work investigated the potential reuse of PCG in Portland cement concrete (PCC) and hot mix asphalt concrete. Several studies were conducted to establish the integrity of the materials containing the recycled grit. These included the chemical and physical characterization of natural sand and PCG, the assay of leaches associated with the grit material for hazardous metal contaminants, such as Cr, Cd and Pb, and the assessment of the mechanical properties of the PCG-substituted mortars by applying special tests (such as Marshall stability and determination of the flow properties) to the PCG-substituted asphalt concrete mixtures. The overall results demonstrated that the potential reuse of PCG in PCC and asphalt concrete mixtures would not pose any environmental threat and could produce several benefits, such as reduced disposal costs, protection of water sources from improper disposal practices and reduced costs in the production of natural aggregates and asphalt cement. PMID:11523444

Taha, R; al-Alawi, D; al-Nabhani, M; Pillay, A E; al-Hamdi, A

2001-08-01

30

Characterization of the Aerosol Generated During Abrasive Blasting with Copper Slag  

Microsoft Academic Search

The National Institute for Occupational Safety and Health (NIOSH) recommends that substi- tute materials be used for silica sand in abrasive blasting operations. Copper slag is commonly used as a substitute for silica sand. These slags have been reported to contain heavy metals. Our research aims were to identify exposure-related differences between slag sources, quantify health-related aerosol fractions for comparison

TERRY M. SPEAR; DALE STEPHENSON; MARIE SEYMOUR

2002-01-01

31

The effect of abrasive blasting on the strength of a joint between dental porcelain and metal base.  

PubMed

This paper presents the effect of selected parameters of abrasive blasting on the strength of a joint between dental porcelain and metal base. Experiments were conducted for different grain sizes of abrasive material and different blasting angles, with a constant blasting pressure. InLine dental porcelain was fused on samples of cobalt-chromium alloy following abrasive blasting; they were subsequently subjected to shearing forces on a testing machine. The fractures were observed under an electron scanning microscope in order to determine the character and course of fracturing. Strength tests showed that the grain size of abrasive material was a parameter with the greatest effect on the strength. The best effects were achieved for samples subjected to abrasive blasting with material with grain size of 110 ?m. No statistically significant differences were found for the strength of samples worked at different angles. The results of the fractographic examinations have shown that in all the samples, fracturing occurred mainly along the porcelain-metal boundary, with few cases of fracturing through porcelain. PMID:24708248

Pietnicki, Krzysztof; Wo?owiec, Emilia; Klimek, Leszek

2014-01-01

32

Adult Stem Cells Properties in Terms of Commitment, Aging and Biological Safety of Grit-Blasted and Acid-Etched Ti Dental Implants Surfaces  

PubMed Central

Titanium (Ti) is one of the most widely used biomaterials for manufacturing dental implants. The implant surface properties strongly influence osseointegration. The aim of the present study was to in vitro investigate the characteristics of Ti dental implants in terms of mutagenicity, hemocompatibility, biocompatibility, osteoinductivity and biological safety. The Ames test was used to test the mutagenicity of the Ti dental implants, and the hemolysis assay for evaluating their hemocompatibility. Human adipose - derived stem cells (ADSCs) were then seeded onto these implants in order to evaluate their cytotoxicity. Gene expression analyzing with real-time PCR was carried out to investigate the osteoinductivity of the biomaterials. Finally, the genetic stability of the cells cultured onto dental implants was determined by karyotyping. Our results demonstrated that Ti dental implants are not mutagenic, do not cause hemolysis, and are biocompatible. The MTT assay revealed that ADSCs, seeded on Ti dental implants, proliferate up to 30 days in culture. Moreover, ADSCs loaded on Ti dental implants show a substantial expression of some osteoblast specific markers, such as COL1A1, OPN, ALPL, and RUNX2, as well as chromosomal stability after 30 days of culture in a medium without osteogenic factors. In conclusion, the grit-blasted and acid-etched treatment seems to favor the adhesion and proliferation of ADSCs and improve the osteoinductivity of Ti dental implant surfaces. PMID:25635249

Gardin, Chiara; Ferroni, Letizia; Bressan, Eriberto; Calvo - Guirado, José L.; Degidi, Marco; Piattelli, Adriano; Zavan, Barbara

2014-01-01

33

Adult stem cells properties in terms of commitment, aging and biological safety of grit-blasted and Acid-etched ti dental implants surfaces.  

PubMed

Titanium (Ti) is one of the most widely used biomaterials for manufacturing dental implants. The implant surface properties strongly influence osseointegration. The aim of the present study was to in vitro investigate the characteristics of Ti dental implants in terms of mutagenicity, hemocompatibility, biocompatibility, osteoinductivity and biological safety. The Ames test was used to test the mutagenicity of the Ti dental implants, and the hemolysis assay for evaluating their hemocompatibility. Human adipose - derived stem cells (ADSCs) were then seeded onto these implants in order to evaluate their cytotoxicity. Gene expression analyzing with real-time PCR was carried out to investigate the osteoinductivity of the biomaterials. Finally, the genetic stability of the cells cultured onto dental implants was determined by karyotyping. Our results demonstrated that Ti dental implants are not mutagenic, do not cause hemolysis, and are biocompatible. The MTT assay revealed that ADSCs, seeded on Ti dental implants, proliferate up to 30 days in culture. Moreover, ADSCs loaded on Ti dental implants show a substantial expression of some osteoblast specific markers, such as COL1A1, OPN, ALPL, and RUNX2, as well as chromosomal stability after 30 days of culture in a medium without osteogenic factors. In conclusion, the grit-blasted and acid-etched treatment seems to favor the adhesion and proliferation of ADSCs and improve the osteoinductivity of Ti dental implant surfaces. PMID:25635249

Gardin, Chiara; Ferroni, Letizia; Bressan, Eriberto; Calvo-Guirado, José L; Degidi, Marco; Piattelli, Adriano; Zavan, Barbara

2014-01-01

34

Effect of erbium-doped: yttrium, aluminium and garnet laser irradiation on the surface microstructure and roughness of sand-blasted, large grit, acid-etched implants  

PubMed Central

Purpose The present study was performed to evaluate the effect of erbium-doped: yttrium, aluminium and garnet (Er:YAG) laser irradiation on sand-blasted, large grit, acid-etched (SLA) implant surface microstructure according to varying energy levels and application times of the laser. Methods The implant surface was irradiated by the Er:YAG laser under combined conditions of 100, 140, or 180 mJ/pulse and an application time of 1 minute, 1.5 minutes, or 2 minutes. Scanning electron microscopy (SEM) was used to examine the surface roughness of the specimens. Results All experimental conditions of Er:YAG laser irradiation, except the power setting of 100 mJ/pulse for 1 minute and 1.5 minutes, led to an alteration in the implant surface. SEM evaluation showed a decrease in the surface roughness of the implants. However, the difference was not statistically significant. Alterations of implant surfaces included meltdown and flattening. More extensive alterations were present with increasing laser energy and application time. Conclusions To ensure no damage to their surfaces, it is recommended that SLA implants be irradiated with an Er:YAG laser below 100 mJ/pulse and 1.5 minutes for detoxifying the implant surfaces. PMID:21811689

Lee, Ji-Hun; Kwon, Young-Hyuk; Herr, Yeek; Shin, Seung-Il

2011-01-01

35

State-of-the-Science Review of the Occupational Health Hazards of Crystalline Silica in Abrasive Blasting Operations and Related Requirements for Respiratory Protection  

Microsoft Academic Search

Excessive exposures to airborne crystalline silica have been known for over 100 years to pose a serious health hazard. Work practices and regulatory standards advanced as the knowledge of the hazards of crystalline silica evolved. This article presents a comprehensive historical examination of the literature on exposure, health effects, and personal protective equipment related to silica and abrasive blasting operations

Amy K. Madl; Ellen P. Donovan; Shannon H. Gaffney; Meg A. McKinley; Emily C. Moody; John L. Henshaw; Dennis J. Paustenbach

2008-01-01

36

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

37

Machining of Aircraft Titanium with Abrasive-Waterjets for Fatigue Critical Applications  

SciTech Connect

Laboratory tests were conducted to determine the fatigue performance of abrasive-waterjet- (AWJ-) machined aircraft titanium. Dog-bone specimens machined with AWJs were prepared and tested with and without sanding and dry-grit blasting with Al2O3 as secondary processes. The secondary processes were applied to remove the visual appearance of AWJ-generated striations and to clean up the garnet embedment. The fatigue performance of AWJ-machined specimens was compared with baseline specimens machined with CNC milling. Fatigue test results of the titanium specimens not only confirmed our previous findings in aluminum dog-bone specimens but in comparison also further enhanced the fatigue performance of the titanium. In addition, titanium is known to be difficult to cut, particularly for thick parts, however AWJs cut the material 34% faster han stainless steel. AWJ cutting and dry-grit blasting are shown to be a preferred ombination for processing aircraft titanium that is fatigue critical.

Liu, H. T.; Hovanski, Yuri; Dahl, Michael E.

2012-02-01

38

Robotic Instrument for Grinding Rocks Into Thin Sections (GRITS)  

NASA Astrophysics Data System (ADS)

We have developed a rock grinding and polishing mechanism for in situ planetary exploration based on abrasive disks, called Grinding Rocks Into Thin Sections (GRITS). Performance characteristics and design considerations of GRITS are presented. GRITS was developed as part of a broader effort to develop an in situ automated rock thin section (ISARTS) instrument. The objective of IS-ARTS was to develop an instrument capable of producing petrographic rock thin sections on a planetary science spacecraft. GRITS may also be useful to other planetary science missions with in situ instruments in which rock surface preparation are necessary.

Paulsen, Gale; Zacny, Kris; Dreyer, Christopher B.; Szucs, Attila; Szczesiak, Matt; Santoro, Chris; Craft, Jack; Hedlund, Magnus; Skok, John

2013-06-01

39

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

40

Development of pollutant release estimates due to abrasive blasting for lead paint removal from New York City Department of Transportation steel bridges  

SciTech Connect

The use of abrasive blasting techniques in the removal of lead paint from steel bridges is a subject of public health and environmental concerns. This process creates airborne dust that must be appropriately contained to prevent inhalation or ingestion exposure during the removal activity, since some of that dust contains lead and other metals. Lead particles, if not appropriately contained, can also settle in local soils or on and within buildings, and can ultimately be inhaled or ingested. Potential worst case release scenarios for the release of dust and pollutants from paint removal operations were developed as part of the analysis framework for the Environmental Impact Statement for Lead Paint Removal Operations on New York City Department of Transportation Bridges. A multi-step analytical framework was developed for the Environmental Impact Statement (EIS), aimed at characterizing and quantifying a series of worst case scenarios for the release of contaminated material into the environment. The pollutants that the analysis focused on were lead, respirable particulates (PM10), Total Suspended Particulates (TSP) and other metals. Samples of existing paint obtained from various surfaces of representative bridges were analyzed to determine average paint dry film thickness and the concentration of metals in the paint for each of the representative bridges. Samples of expendable abrasives were analyzed to determine the concentration of metals within the abrasives. Six scenarios were developed to encompass the range of potential releases that can occur during blasting operations. Two subcategories of hypothetical release events were developed for each scenario-- reasonable worst case events and maximum worst case events. Air quality dispersion modeling with the Environmental Protection Agency's ISC3ST model was employed with the predicted release rates.

Lee, M.; Domanski, J.

1999-07-01

41

Potential Use of Abrasive Air-Propelled Agricultural Residues for Weed Control  

Technology Transfer Automated Retrieval System (TEKTRAN)

A new postemergence weed control tactic is proposed for organic production systems that results in plant abrasion and death upon assault from abrasive grits propelled by compressed air. Grit derived from granulated walnut shells was delivered by a sand blaster at 517 kPa at distances of 30 to 60 cm ...

42

Corneal Abrasions  

MedlinePLUS

... injury called a corneal abrasion. What Is a Corneal Abrasion? Most of your eyeball sits in a ... other problems. What Are the Symptoms of a Corneal Abrasion? A corneal abrasion affects the way the ...

43

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

44

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

45

Dry ice blasting  

NASA Astrophysics Data System (ADS)

As legal and societal pressures against the use of hazardous waste generating materials has increased, so has the motivation to find safe, effective, and permanent replacements. Dry ice blasting is a technology which uses CO2 pellets as a blasting medium. The use of CO2 for cleaning and stripping operations offers potential for significant environmental, safety, and productivity improvements over grit blasting, plastic media blasting, and chemical solvent cleaning. Because CO2 pellets break up and sublime upon impact, there is no expended media to dispose of. Unlike grit or plastic media blasting which produce large quantities of expended media, the only waste produced by CO2 blasting is the material removed. The quantity of hazardous waste produced, and thus the cost of hazardous waste disposal is significantly reduced.

Lonergan, Jeffrey M.

1992-04-01

46

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

47

Corneal Abrasions  

MedlinePLUS

... exam the next day. What if I wear contact lenses? If you wear contact lenses, you need to be especially careful with a ... doctor may tell you not to wear your contact lenses for a few days after a corneal abrasion, ...

48

Corneal Abrasions  

MedlinePLUS

... lenses, bright lights, and reactions to things like contact lens solutions and eye makeup. Continue What Are the Signs of a Corneal Abrasion? Because they affect the way the cornea functions, ... medications. If you normally wear contact lenses, the doctor may tell you not to ...

49

Abrasion and deformed layer formation of manganese-zinc ferrite in sliding contact with lapping tapes  

NASA Technical Reports Server (NTRS)

Wear experiments were conducted using replication electron microscopy and reflection electron diffraction to study abrasion and the deformed layers produced in single-crystal Mn-Zn ferrite simulated heads during contact with lapping tapes. The crystaline state of the head is changed drastically during the abrasion process. Crystalline states ranging from nearly amorphous to highly textured polycrystalline can be produced on the wear surface of a single-crystal Mn-Zn ferrite head. The total thickness of the deformed layer was approximately 0.8 microns. This thickness increased as the load and abrasive grit size increased. The anisotropic wear of the ferrite was found to be inversely proportional to the hardness of the wear surface. The wear was lower in the order 211 111 10 0110. The wear of the ferrite increased markedly with an increase in sliding velocity and abrasive grit size.

Miyoshi, K.; Buckley, D. H.; Tanaka, K.

1986-01-01

50

High resolution powder blast micromachining  

Microsoft Academic Search

Powder blasting, or Abrasive Jet Machining (AJM), is a technique in which a particle jet is directed towards a target for mechanical material removal. It is a fast, cheap and accurate directional etch technique for brittle materials like glass, silicon and ceramics. By introducing electroplated copper as a new mask material, the feature size of this process was decreased. It

Henk Wensink; J. W. Berenschot; Henri V. Jansen; Miko C. Elwenspoek

2000-01-01

51

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

52

Metal leaching from the bridge paint waste in the presence of steel grit.  

PubMed

The disposal of paint waste from bridge rehabilitation is a significant issue because of the potential release of contaminants and the consequent impact to human health and the environment. In this study, leaching behavior of paint waste was evaluated for 24 bridges in New York State. Although elevated Pb (5-168,090mgkg(-1)) and other metal concentrations were observed in the paint samples, leaching experiments that included the toxicity characteristic leaching procedure (TCLP) and the multiple extraction procedure (MEP) revealed toxicity characteristic (TC) limits were not exceeded. The relatively low concentrations observed are attributed to the use of iron-based abrasives (steel grit) in the paint removal process. In this research, trace metals are hypothesized to be sequestered through interactions with iron oxide coatings formed on the steel grit surface resulting in reduced leachable concentrations. Through sequential extraction iron oxides were observed at 11.03% by wt and X-ray diffraction (XRD) further corroborated the presence of iron oxide coatings on the steel grit surface. Sequential extraction demonstrated that less than 6.8% of Pb, Cr, and Ba were associated with the exchangeable and carbonate forms, while greater contributions were found with iron oxides. The largest fraction, however, greater than 80%, was associated with the residual phase comprised of minerals in the paint including SiO2 and TiO2. PMID:25460749

Shu, Zhan; Axe, Lisa; Jahan, Kauser; Ramanujachary, Kandalam V

2015-01-01

53

Effect of workpiece properties on machinability in abrasive jet machining of ceramic materials  

Microsoft Academic Search

Abrasive jet machining (AJM), a specialized form of shot blasting using fine-grained abrasives, is an attractive micro-machining method for ceramic materials. In this paper, the machinability during the AJM process is compared to that given by the established models of solid particle erosion, in which the material removal is assumed to originate in the ideal crack formation system. However, it

M. Wakuda; Y. Yamauchi; S. Kanzaki

2002-01-01

54

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

55

ORIGINAL PAPER Use of grit supplements by waterbirds: an experimental  

E-print Network

in the gizzard and in some species also as a dietary supplement (Gionfriddo and Best 1999). However, this impliesORIGINAL 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

Green, Andy J.

56

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

57

Solidification/stabilization of spent abrasives and use as nonstructural concrete  

SciTech Connect

Tons of spent abrasives result each year from the removal of old paint from bridges. Because the spent abrasives contain metals from the paint, some spent abrasives may be considered hazardous by the Toxicity Characteristic (TC) criteria. Incorporation of the spent blasting abrasives in nonstructural concrete (rip-rap, dolphins) offers an opportunity to recycle the spent abrasives while immobilizing potentially leachable metals. This study focused on the Portland Cement Solidification/Stabilization (S/S) of spent blasting abrasives taken from a bridge located in Southeast Texas. The study examined (a) the cadmium, chromium, and lead concentrations in extracts obtained by using the Toxicity Characteristic Leaching Procedure (TCLP) and (b) the compressive strengths of Portland Cement mixes that contained different amounts of the spent abrasives. Performance was measured by meeting the TC criteria as well as the requirements for compressive strength. Study results indicated that considerable quantities of these spent abrasives can be solidified/stabilized while reducing the leachability of cadmium, chromium, and lead and producing compressive strengths over 6,895 kN/m[sup 2] (1,000 psi).

Brabrand, D.J.; Loehr, R.C. (Univ. of Texas, Austin, TX (United States))

1993-01-01

58

Surface modification of titanium implants using bioactive glasses with air abrasion technologies  

Microsoft Academic Search

A growing number of surface treated titanium implants are routinely used in dental and orthopaedic surgery, with a view to\\u000a enhancing integration capacity with osseous tissue. This study examines the use of bioactive glass 45S5 as an alternative\\u000a abrasive and osteoproductive surface modification material. Abrasive blasting of commercially pure titanium with bioactive\\u000a glass 45S5 produced an irregular finish with a

Garrit Koller; Richard J. Cook; Ian D. Thompson; Timothy F. Watson; Lucy Di Silvio

2007-01-01

59

Abrasion resistant heat pipe  

DOEpatents

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

Ernst, D.M.

1984-10-23

60

In vitro biological effects of titanium rough surface obtained by calcium phosphate grid blasting  

Microsoft Academic Search

Surface roughness modulates the osseointegration of orthopaedic and dental titanium implants. High surface roughness are currently obtained by blasting of titanium implants with silica or aluminium oxide abrasive particles. This process may cause the release of cytotoxic silicium or aluminium ions in the peri-implant tissue. To generate a biocompatible roughened titanium surface, we currently develop an innovative grid-blasting process using

Anthony Citeau; Jerome Guicheux; Claire Vinatier; Pierre Layrolle; Thien P Nguyen; Paul Pilet; Guy Daculsi

2005-01-01

61

Abrasion protection in process piping  

SciTech Connect

Process piping often is subjected to failure from abrasion or a combination of abrasion and corrosion. Abrasion is a complex phenomenon, with many factors involved to varying degrees. Hard, mineral based alumina ceramic and basalt materials are used to provide protection against abrasion in many piping systems. Successful life extension examples are presented from many different industries. Lined piping components require special attention with regard to operating conditions as well as design and engineering considerations. Economic justification involves direct cost comparisons and avoided costs.

Accetta, J. [Abresist Corp., Urbana, IN (United States)

1996-07-01

62

Abrasion resistant composition  

DOEpatents

A surface covering composition of abrasion resistant character adapted for disposition in overlying bonded relation to a metal substrate. The surface covering composition includes metal carbide particles within a metal matrix at a packing factor of not less than about 0.6. Not less than about 40 percent by weight of the metal carbide particles are characterized by an effective diameter in the range of +14-32 mesh prior to introduction to the metal matrix. Not less than about 3 percent by weight of the metal carbide particles are characterized by an effective diameter of +60 mesh prior to introduction to the metal matrix.

Fischer, Keith D; Barnes, Christopher A; Henderson, Stephen L

2014-05-13

63

Blast injury.  

PubMed

The shock wave generated by an explosion ("blast wave") may cause injury in any or all of the following: (1) direct impact on the tissues of variations in environmental pressure; (2) flying glass and other debris set in motion by it; (3) propulsion of the body. Injuries in the first category affect gas-containing organs (ears, lungs and intestines), and acute death is attributed to air forced into the coronary vessels via damaged pulmonary alveoli. It is estimated that overpressure sufficient to cause lung injury may occur up to five miles from a 20-megaton nuclear explosion. The greatest single hazard from blast is, however, flying glass, and serious wounding from this cause is possible up to 12 miles from an explosion of this magnitude. PMID:6015742

de Candole, C A

1967-01-28

64

Blast Injury  

PubMed Central

The shock wave generated by an explosion (“blast wave”) may cause injury in any or all of the following: (1) direct impact on the tissues of variations in environmental pressure; (2) flying glass and other debris set in motion by it; (3) propulsion of the body. Injuries in the first category affect gas-containing organs (ears, lungs and intestines), and acute death is attributed to air forced into the coronary vessels via damaged pulmonary alveoli. It is estimated that overpressure sufficient to cause lung injury may occur up to five miles from a 20-megaton nuclear explosion. The greatest single hazard from blast is, however, flying glass, and serious wounding from this cause is possible up to 12 miles from an explosion of this magnitude. PMID:6015742

de Candole, C. A.

1967-01-01

65

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

66

An Experimental Study on the Fabrication of Glass-based Acceleration Sensor Body Using Micro Powder Blasting Method  

Microsoft Academic Search

This study investigated the feasibility of the micr o powder blasting technique for the micro fabrication of sensor structures using th e Pyrex glass to replace the existing silicon-based acceleration sensor fabrication proce sses. As the preliminary experiments, the effects of the blasting pressure, the mass flow rat e of abrasive and the number of nozzle scanning times on erosion

Dong-Sam Park; Dae-Jin Yun; Myeong-Woo Cho; Bong-Cheol Shin

2007-01-01

67

Tooth Abrasion and Tooth Erosion  

MedlinePLUS

... protects the innermost part of the tooth, the pulp, which contains nerves and blood vessels. Abrasion and ... can damage the center of the tooth, the pulp. The more damage is done, the more work ...

68

The Significance of Grit: A Conversation with Angela Lee Duckworth  

ERIC Educational Resources Information Center

For the last 11 years, Angela Lee Duckworth of the University of Pennsylvania has been conducting ground breaking studies on "grit"--the quality that enables individuals to work hard and stick to their long-term passions and goals. In this interview with "Educational Leadership," Duckworth describes what her research has shown…

Perkins-Gough, Deborah

2013-01-01

69

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

70

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

71

Conduit Coating Abrasion Testing  

NASA Technical Reports Server (NTRS)

During my summer internship at NASA I have been working alongside the team members of the RESTORE project. Engineers working on the RESTORE project are creating ·a device that can go into space and service satellites that no longer work due to gas shortage or other technical difficulties. In order to complete the task of refueling the satellite a hose needs to be used and covered with a material that can withstand effects of space. The conduit coating abrasion test will help the researchers figure out what type of thermal coating to use on the hose that will be refueling the satellites. The objective of the project is to determine whether or not the conduit coating will withstand the effects of space. For the RESTORE project I will help with various aspects of the testing that needed to be done in order to determine which type of conduit should be used for refueling the satellite. During my time on the project I will be assisting with wiring a relay board that connected to the test set up by soldering, configuring wires and testing for continuity. Prior to the testing I will work on creating the testing site and help write the procedure for the test. The testing will take place over a span of two weeks and lead to an informative conclusion. Working alongside various RESTORE team members I will assist with the project's documentation and records. All in all, throughout my internship at NASA I hope to learn a number of valuable skills and be a part of a hard working team of engineers.

Sullivan, Mary K.

2013-01-01

72

Should we be gritting pavements to prevent pedestrian injuries?  

PubMed

Unintentional injuries are an important public health issue, and are a significant burden on health and social services, especially during the winter months. Dr Rob Atenstaedt, Consultant in Public Health Medicine, Public Health Wales & Honorary Senior Lecturer, Bangor University and Professor Michael Rees, University Director of Medical Development & Professor of Cardiovascular Studies, Bangor University look at the importance of pavement gritting in preventing injuries and falls in pedestrians. PMID:23657235

Atenstaedt, Rob; Rees, Michael

2013-05-01

73

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

74

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

75

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

76

Optimal Blast Condition for the Inner Surface of Mass Produced NAS Battery Cylindrical Aluminum Cell Containers as Pretreatment of Thermal Spraying  

NASA Astrophysics Data System (ADS)

The relationship between roughness caused by blasting and adhesion of spray coatings on aluminum container substrates was studied through various experiments as part of measures for improving the adhesion of the 75mass%Cr-Fe alloy plasma spray coating for sulfi dation corrosion resistance, which is applied on the inner surface of cylindrical Al containers of high-temperature type NAS batteries. Surface roughness of ?mRa2.8 - 7.3 was acquired by using Al2O3 particle size #100 (212 - 75?m) to #46 (600 - 250?m) grit. In order to achieve uniform roughness and a clean surface, a combination of blasting when the nozzle was being inserted from the top of the container, and air blowing when the nozzle was being removed was done. It was determined that when Al2O3 particles of size #100 grit was used, a good anchoring shape was formed throughout with a roughened surface of ?mRa 2.8. When the internal surface of 3000 Al cylindrical containers were continually blasted using particle size #100 grit, the initial surface roughness of ?mRa3.7 - 3.9 only deteriorated to about ?mRa2.6. A 75mass%Cr-Fe alloy spray coating was applied to the Al cylindrical containers that were roughened using particle size #100 grit. This coating showed cracks by a bending test, but no peeling occurred. This coating was examined by a tensile strength test and showed good adhesion at 64 - 66 MPa. Through experiments, it was proven that spray coatings formed on the Al cylindrical containers after receiving optimal blasting with particle size #100 grit had good adhesion and corrosion resistance after being used for NAS batteries that stored electrical power for about nine years.

Ando, Takashi; Harada, Yoshio

77

Turkana Grits - a Cretaceous braided alluvial system in northern Kenya  

SciTech Connect

Rather spotty but excellent exposures of the Cretaceous-age Turkana Grits occur near the western shore of Lake Turkana, northern Kenya. These very coarse to pebbly arkosic sandstones and sandy conglomerates were derived from and rest unconformably upon Precambrian metamorphic basement; they are overlain by late Tertiary basaltic flows that comprise much of the volcanics in the East African Rift Zone. The formation ranges up to 2000 ft thick in the Laburr Range. Several outcrops contain sauropod, crocodile, and tortoise remains as well as abundant trunks of petrified wood (Dryoxylon). Five major facies make up the Turkana Grits and record a major episode of continental fluvial deposition in basins flanked by Precambrian basement. Facies 1 is crudely stratified, cobble and boulder conglomerate (clast-supported); Facies 2 is crudely stratified pebble-cobble conglomerate and pebbly sandstone; Facies 3 is trough cross-bedded, very coarse sandstones containing fossils wood and vertebrate remains; Facies 4 is crudely stratified to massive sandstones with ironstone nodules; and Facies 5 is red, purple, and gray mudstone and mud shale with carbonate nodules. Facies 1 through 3 record deposition in proximal to medial braided-stream channel, longitudinal bar and dune complexes. Facies 4 is a lowland, hydromorphic paleosol, and Facies 5 represents overbank and abandoned channel-fill sedimentation in an alluvial plain.

Handford, C.R.

1987-05-01

78

Modification of corn grits for gas drying in Skarstrom pressure swing cycle  

SciTech Connect

Starch and starch-based materials can adsorb moisture from air or organic vapors, and are used commercially to dry 2.8 billion liters of fuel grade fermentation ethanol, annually. Corn grits have been used in a Pressure Swing Adsorption System (PSA) to produce dry (low dew point) air. The PSA system used for this work operates on the Skarstrom process. When used in the PSA system, 2.16 mm corn grits (8/10 sieve size) can dry moist air to a dew point of -42{degrees}C, and 1.0 mm grits (18 sieve size) can dry moist air to a dew point of -69{degrees}C. These grits are stable over at least 250,000 cycles of operation in the PSA system. Possible applications of using corn grits in the pressure swing adsorption system include dryers for industrial gases, sorptive cooling air conditioners, and recycling equipment for industrial solvents. The corn grits are an attractive sorbent because they are non-toxic, biodegradable, environmentally safe, durable, and inexpensive. A modification technology has been developed for the corn grits that gives dew points in the PSA system as low as those of molecular sieves while maintaining a constant particle size. By applying the modification process, the 2.16 mm corn grits are able to dry moist air to a -56{degrees}C dew point and the 1.0 mm corn grits can dry air to a -80{degrees}C dew point (which is the detection limit of the hygrometer used in our research). It is believed that the modification process creates pores in the corn grits which could make more -OH groups accessible for hydrogen bonding with the polar water groups. The relation between the structure of polysaccharides in corn and their functioning in complexing with water is discussed. 11 refs., 1 fig., 1 tab.

Beery, K.E.; Gulati, M.; Brewer, M.A.; Hendrickson, R.L.; Ladisch, M.R. [Purdue Univ., West Lafayette, IN (United States)

1996-12-31

79

A Study on Abrasive Water Jet Machining of Aluminum with Garnet Abrasives  

Microsoft Academic Search

In this study the effect of some cutting variables on the quality of the surface produced during abrasive water jet machining of aluminum has been investigated. The type of abrasive used was garnet of mesh size 80. The machining was done on the abrasive water jet machine WJ4080. The cutting variables were stand-off distance of the nozzle from the work

Ahsan Ali Khan; Noraziaty Bt. Munajat; Harnisah Bt. Tajudin

2005-01-01

80

Blast furnace stove control  

SciTech Connect

This paper outlines the process model and model-based control techniques implemented on the hot blast stoves for the No. 7 Blast Furnace at the Inland Steel facility in East Chicago, Indiana. A detailed heat transfer model of the stoves is developed. It is then used as part of a predictive control scheme to determine the minimum amount of fuel necessary to achieve the blast air requirements. The controller also considers maximum and minimum temperature constraints within the stove.

Muske, K.R. [Villanova Univ., PA (United States). Dept. of Chemical Engineering; Hansen, G.A.; Howse, J.W.; Cagliostro, D.J. [Los Alamos National Lab., NM (United States); Chaubal, P.C. [Inland Steel Industries Inc., East Chicago, IN (United States). Research Labs.

1998-12-31

81

Blast injury research models  

PubMed Central

Blast injuries are an increasing problem in both military and civilian practice. Primary blast injury to the lungs (blast lung) is found in a clinically significant proportion of casualties from explosions even in an open environment, and in a high proportion of severely injured casualties following explosions in confined spaces. Blast casualties also commonly suffer secondary and tertiary blast injuries resulting in significant blood loss. The presence of hypoxaemia owing to blast lung complicates the process of fluid resuscitation. Consequently, prolonged hypotensive resuscitation was found to be incompatible with survival after combined blast lung and haemorrhage. This article describes studies addressing new forward resuscitation strategies involving a hybrid blood pressure profile (initially hypotensive followed later by normotensive resuscitation) and the use of supplemental oxygen to increase survival and reduce physiological deterioration during prolonged resuscitation. Surprisingly, hypertonic saline dextran was found to be inferior to normal saline after combined blast injury and haemorrhage. New strategies have therefore been developed to address the needs of blast-injured casualties and are likely to be particularly useful under circumstances of enforced delayed evacuation to surgical care. PMID:21149352

Kirkman, E.; Watts, S.; Cooper, G.

2011-01-01

82

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

83

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.

84

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

85

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

86

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

1994-01-01

87

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

88

Turning of glass with abrasive waterjet  

Microsoft Academic Search

This article reports research results on abrasive waterjet (AWJ) turning of glass. Glass rods, 25 mm in diameter, were turned by using AWJ to investigate the effects of several process parameters on the surface quality of the machined glass surfaces. The parameters studied are rotational speed, stand-off distance, water pressure, nozzle traverse speed, and abrasive flow rate. The results were also

Z. W. Zhong; Z. Z. Han

2002-01-01

89

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

90

Reuse of grits waste for the production of soil--cement bricks.  

PubMed

This investigation focuses on the reuse of grits waste as a raw material for replacing Portland cement by up to 30 wt.% in soil-cement bricks. The grits waste was obtained from a cellulose factory located in south-eastern Brazil. We initially characterized the waste sample with respect to its chemical composition, X-ray diffraction, fineness index, morphology, pozzolanic activity, and pollution potential. Soil-cement bricks were then prepared using the waste material and were tested to determine their technological properties (e.g., water absorption, apparent density, volumetric shrinkage, and compressive strength). Microstructural evolution was accompanied by confocal microscopy. It was found that the grits waste is mainly composed of calcite (CaCO3) particles. Our results indicate that grits waste can be used economically, safely, and sustainably at weight percentages of up to 20% to partially replace Portland cement in soil-cement bricks. PMID:24140481

Siqueira, F B; Holanda, J N F

2013-12-15

91

Passive blast pressure sensor  

SciTech Connect

A passive blast pressure sensor for detecting blast overpressures of at least a predetermined minimum threshold pressure. The blast pressure sensor includes a piston-cylinder arrangement with one end of the piston having a detection surface exposed to a blast event monitored medium through one end of the cylinder and the other end of the piston having a striker surface positioned to impact a contact stress sensitive film that is positioned against a strike surface of a rigid body, such as a backing plate. The contact stress sensitive film is of a type which changes color in response to at least a predetermined minimum contact stress which is defined as a product of the predetermined minimum threshold pressure and an amplification factor of the piston. In this manner, a color change in the film arising from impact of the piston accelerated by a blast event provides visual indication that a blast overpressure encountered from the blast event was not less than the predetermined minimum threshold pressure.

King, Michael J.; Sanchez, Roberto J.; Moss, William C.

2013-03-19

92

Effects of calcium ion implantation on osseointegration of surface-blasted titanium alloy femoral implants in a canine total hip arthroplasty model  

Microsoft Academic Search

Osteoconductivity of titanium-alloy implants may be improved when surface-modified by calcium ion (Ca2+) implantation. We studied the effects of Ca2+ implantation on osseointegration of a grit-blasted titanium-alloy stem using a canine total hip arthroplasty model. Fifteen dogs underwent bilateral hip arthroplasties and were sacrificed at 1, 6, and 12 months postoperatively. The hip components were evaluated by radiographic, qualitative, and

Tetsuya Jinno; Sarah K Kirk; Sadao Morita; Victor M Goldberg

2004-01-01

93

Performance of different abrasive materials during abrasive water jet machining of glass  

Microsoft Academic Search

Different types of abrasives are used in abrasive water-jet machining like garnet, aluminum oxide, olivine, silica sand, silicon carbide, etc. The present work gives a comparative analysis of the performance of garnet, aluminum oxide and silicon oxide during abrasive water-jet machining of glass. The study showed that width of cut increases as the stand-off distance of the nozzle from the

A. A. Khan; M. M. Haque

2007-01-01

94

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

95

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

96

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

97

Surface modification of titanium using steel slag ball and shot blasting treatment for biomedical implant applications  

NASA Astrophysics Data System (ADS)

Surface modification is often performed using grit or shot blasting treatment for improving the performances of biomedical implants. The effects of blasting treatments using steel slag balls and spherical shots on the surface and subsurface of titanium were studied in this paper. The treatments were conducted for 60-300 s using 2-5 mm steel slag balls and 3.18 mm spherical shots. The surface morphology, roughness, and elemental composition of titanium specimens were examined prior to and after the treatments. Irregular and rough titanium surfaces were formed after the treatment with the steel slag balls instead of the spherical shots. The former treatment also introduced some bioactive elements on the titanium surface, but the latter one yielded a harder surface layer. In conclusion, both steel slag ball and shot blasting treatment have their own specialization in modifying the surface of metallic biomaterials. Steel slag ball blasting is potential for improving the osseointegration quality of implants; but the shot blasting is more appropriate for improving the mechanical properties of temporary and load bearing implants, such as osteosynthesis plates.

Arifvianto, Budi; Suyitno; Mahardika, Muslim

2013-08-01

98

30 CFR 75.1323 - Blasting circuits.  

Code of Federal Regulations, 2012 CFR

...Blasting § 75.1323 Blasting circuits. (a) Blasting circuits shall be protected from sources of stray electric current. (b) Detonators made...not be combined in the same blasting circuit. (c) Detonator leg wires...

2012-07-01

99

30 CFR 75.1323 - Blasting circuits.  

Code of Federal Regulations, 2013 CFR

...Blasting § 75.1323 Blasting circuits. (a) Blasting circuits shall be protected from sources of stray electric current. (b) Detonators made...not be combined in the same blasting circuit. (c) Detonator leg wires...

2013-07-01

100

30 CFR 75.1323 - Blasting circuits.  

Code of Federal Regulations, 2011 CFR

...Blasting § 75.1323 Blasting circuits. (a) Blasting circuits shall be protected from sources of stray electric current. (b) Detonators made...not be combined in the same blasting circuit. (c) Detonator leg wires...

2011-07-01

101

30 CFR 75.1323 - Blasting circuits.  

Code of Federal Regulations, 2014 CFR

...Blasting § 75.1323 Blasting circuits. (a) Blasting circuits shall be protected from sources of stray electric current. (b) Detonators made...not be combined in the same blasting circuit. (c) Detonator leg wires...

2014-07-01

102

Measurement and analysis of clinical abrasion--a modified approach.  

PubMed

The abrasion of three posterior composites, after three years' clinical service, was measured by use of a calibrated stone step-wedge. The enamel exposure by each cusp was measured, so that the maximum and overall abrasion could be calculated. The results indicated uneven abrasion around the margin, signifying that local factors, acting by each cusp, had a significant effect on abrasion. This differs from the behavior of the earlier composites, where there was uniform abrasion around the margins. The overall abrasion had a nonparametric distribution, and frequency distribution diagrams proved to be the best way of comparing the performances of the individual materials. PMID:2086305

Mair, L H

1990-10-01

103

Influence of granite-grit on nutrient digestibility and haematological parameters of broiler chickens fed rice offal based diets.  

PubMed

A total of 270 broiler chickens were used for the study. The birds were fed common diet containing 23% Crude protein and 2864 kcal kg(-1) Metabolizable energy at the starter phase while 20% Crude protein and 2923 kcal kg(-1) Metabolizable energy was fed at the finisher phase. Starter and finisher diets contained 10 and 15% inclusion levels of rice offal respectively. Granite grit was added to the basal diet at 0.0, 2.0, 4.0, 6.0, 8.0 and 10.0 g per bird per month thus making a total of six treatments. Each treatment was replicated three times with 15 birds per replicate in a completely randomized design. Packed cell volume and haemoglobin level were not significantly (p>0.05) affected by dietary grit levels while total protein increased across the graded levels of granite grit. Crude protein, crude fibre and nitrogen free extract significantly (p<0.05) improved with increasing grit levels. These parameters improved up to the highest level of grit addition (10.0 g) granite-grit. It was concluded that 10.0 g granite grit per bird per month is beneficial to broiler chickens as it allows for efficient nutrient utilization. Further study to determine the optimum level of granite grit in broiler diet is encouraged since result obtained showed the optimum level was not attained. PMID:24502172

Idachaba, C U; Abeke, F O; Olugbemi, T S; Ademu, L A

2013-10-01

104

Abrasion resistant valves cut platform maintenance cost  

SciTech Connect

Shell Exploration and Production, operator of Brent field in the UK North Sea, turned to Anglo-US valve maker Serck Audco Valves for help in solving persistent valve maintenance problems. Brent Charlie platform was selected as a test site for the supplier`s new line of abrasion-resistant valves. The most common failure cause is abrasion by solids in the line fluid, particularly sand, which damages even stainless steel and Duplex valve seats, creating leak paths which prevent valve sealing. Serck Audco manufacturers the Super-H all-metal pressure-balanced plug valve, which has proved particularly resistant to erosion in some of the world`s harshest operating environments. The paper describes the valve`s extra abrasion resistance and the Brent Charlie test.

NONE

1997-02-01

105

An investigation into magnetic electrolytic abrasive turning  

NASA Astrophysics Data System (ADS)

The magnetic electrolytic abrasive turning (MEAT) process as a non-traditional machining is used to obtain surface finishing like mirror. MEAT provides one of the best alternatives for producing complex shapes with good finish in advanced materials used in aircraft and aerospace industries. The improvement of machining accuracy of MEAT continues to be a major challenge for modern industry. MEAT is a hybrid machining which combines two or more processes to remove material. The present research focuses on the development of precision electrochemical turning (ECT) under the effects of magnetic field and abrasives. The effect of magnetic flux density, electrochemical conditions and abrasive parameters on finishing efficiency and surface roughness are investigated. An empirical relationship is deduced.

Mahdy, M. A. M.; Ismaeial, A. L.; Aly, F. F.

2013-07-01

106

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

107

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

108

Friction and abrasion of elastomeric materials  

NASA Technical Reports Server (NTRS)

An abrasion apparatus is described. Experimental measurements are reported for four representative elastomeric materials, including a typical high-quality tire tread material and a possible replacement material for aircraft tire treads based on transpolypentenamer (TPPR). Measurements are carried out at different levels of frictional work input, corresponding to different severities of wear, and at both ambient temperature and at 100 C. Results indicate the marked superiority in abrasion resistance of the material based on TPPR, especially at 100 C, in comparison with the other materials examined.

Gent, A. N.

1975-01-01

109

29 CFR 1926.303 - Abrasive wheels and tools.  

Code of Federal Regulations, 2014 CFR

...guard may be omitted; and (ii) The spindle end, nut, and outer flange may be exposed on machines designed as portable saws. (c) Use of abrasive wheels. (1) Floor stand and bench mounted abrasive wheels, used for external grinding,...

2014-07-01

110

29 CFR 1926.303 - Abrasive wheels and tools.  

Code of Federal Regulations, 2011 CFR

...guard may be omitted; and (ii) The spindle end, nut, and outer flange may be exposed on machines designed as portable saws. (c) Use of abrasive wheels. (1) Floor stand and bench mounted abrasive wheels, used for external grinding,...

2011-07-01

111

29 CFR 1926.303 - Abrasive wheels and tools.  

Code of Federal Regulations, 2013 CFR

...guard may be omitted; and (ii) The spindle end, nut, and outer flange may be exposed on machines designed as portable saws. (c) Use of abrasive wheels. (1) Floor stand and bench mounted abrasive wheels, used for external grinding,...

2013-07-01

112

29 CFR 1926.303 - Abrasive wheels and tools.  

Code of Federal Regulations, 2012 CFR

...FOR CONSTRUCTION Tools-Hand and Power...Abrasive wheels and tools. (a) Power. All grinding machines shall be supplied...abrasive wheels and tools used by employees...On offhand grinding machines, work rests...

2012-07-01

113

21 CFR 872.6010 - Abrasive device and accessories.  

Code of Federal Regulations, 2014 CFR

...accessories. (a) Identification. An abrasive device and accessories is a device constructed of various abrasives, such as diamond chips, that are glued to shellac-based paper. The device is intended to remove excessive restorative materials,...

2014-04-01

114

Facile fabrication of superhydrophobic surface with excellent mechanical abrasion and corrosion resistance on copper substrate by a novel method.  

PubMed

A novel method for controllable fabrication of a superhydrophobic surface with a water contact angle of 162 ± 1° and a sliding angle of 3 ± 0.5° on copper substrate is reported in this Research Article. The facile and low-cost fabrication process is composed from the electrodeposition in traditional Watts bath and the heat-treatment in the presence of (heptadecafluoro-1,1,2,2-tetradecyl) triethoxysilane (AC-FAS). The superhydrophobicity of the fabricated surface results from its pine-cone-like hierarchical micro-nanostructure and the assembly of low-surface-energy fluorinated components on it. The superhydrophobic surface exhibits high microhardness and excellent mechanical abrasion resistance because it maintains superhydrophobicity after mechanical abrasion against 800 grit SiC sandpaper for 1.0 m at the applied pressure of 4.80 kPa. Moreover, the superhydrophobic surface has good chemical stability in both acidic and alkaline environments. The potentiodynamic polarization and electrochemical impedance spectroscopy test shows that the as-prepared superhydrophobic surface has excellent corrosion resistance that can provide effective protection for the bare Cu substrate. In addition, the as-prepared superhydrophobic surface has self-cleaning ability. It is believed that the facile and low-cost method offer an effective strategy and promising industrial applications for fabricating superhydrophobic surfaces on various metallic materials. PMID:24796223

Su, Fenghua; Yao, Kai

2014-06-11

115

Dust transport and abrasion assessment within simulated standing vegetation  

Technology Transfer Automated Retrieval System (TEKTRAN)

Crop residues are useful in protecting the top soil from depletion and abrasion due to wind erosion. A wind tunnel study was done to measure sand transport and abrasion energies within the simulated artificial standing vegetation. Wind profiles, relative abrasion energies and rates of sand dischar...

116

Abrasion resistance of nanostructured and conventional cemented carbides  

Microsoft Academic Search

The abrasion resistance of nanostructured WC?Co composites, synthesized by a novel spray conversion method, is determined and compared with that of conventional materials. Scratching by diamond indenter and abrasion by hard (diamond), soft (zirconia) and intermediate (SiC) abrasives was investigated. The size of the scratch formed by the diamond is simply related to the hardness of the composite. Plastic deformation,

K. Jia; T. E. Fischer

1996-01-01

117

21 CFR 872.6030 - Oral cavity abrasive polishing agent.  

Code of Federal Regulations, 2014 CFR

...An oral cavity abrasive polishing agent is a device in paste or powder form that contains an abrasive material, such as silica pumice, intended to remove debris from the teeth. The abrasive polish is applied to the teeth by a handpiece attachment...

2014-04-01

118

21 CFR 872.6030 - Oral cavity abrasive polishing agent.  

Code of Federal Regulations, 2012 CFR

...An oral cavity abrasive polishing agent is a device in paste or powder form that contains an abrasive material, such as silica pumice, intended to remove debris from the teeth. The abrasive polish is applied to the teeth by a handpiece attachment...

2012-04-01

119

21 CFR 872.6030 - Oral cavity abrasive polishing agent.  

Code of Federal Regulations, 2013 CFR

...An oral cavity abrasive polishing agent is a device in paste or powder form that contains an abrasive material, such as silica pumice, intended to remove debris from the teeth. The abrasive polish is applied to the teeth by a handpiece attachment...

2013-04-01

120

21 CFR 872.6030 - Oral cavity abrasive polishing agent.  

Code of Federal Regulations, 2011 CFR

...An oral cavity abrasive polishing agent is a device in paste or powder form that contains an abrasive material, such as silica pumice, intended to remove debris from the teeth. The abrasive polish is applied to the teeth by a handpiece attachment...

2011-04-01

121

21 CFR 872.6030 - Oral cavity abrasive polishing agent.  

Code of Federal Regulations, 2010 CFR

...An oral cavity abrasive polishing agent is a device in paste or powder form that contains an abrasive material, such as silica pumice, intended to remove debris from the teeth. The abrasive polish is applied to the teeth by a handpiece attachment...

2010-04-01

122

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

123

Rock Abrasion Tool: Mars Exploration Rover mission  

Microsoft Academic Search

The Rock Abrasion Tool (RAT) is an integral part of the Athena Science payload. Serving primarily as the geologist's rock hammer, the RAT will expose fresh surfaces of Martian rocks to other instruments on the payload. The RAT also brushes dust and debris from an excavated hole or unaltered rocks. To accomplish these tasks autonomously, the RAT, a sophisticated 3-axis

S. P. Gorevan; T. Myrick; K. Davis; J. J. Chau; P. Bartlett; S. Mukherjee; R. Anderson; S. W. Squyres; R. E. Arvidson; M. B. Madsen; P. Bertelsen; W. Goetz; C. S. Binau; L. Richter

2003-01-01

124

Cleaning Power and Abrasivity of European Toothpastes  

Microsoft Academic Search

For 41 toothpastes available to European consumers in 1995, the cleaning efficacy was evaluated in comparison with abrasivity on dentin (RDA value). For cleaning power assessment, a modified pellicle cleaning ratio (PCR) measurement method was developed. The method is characterized by a five-day tea-staining procedure on bovine front teeth slabs on a rotating wheel, standardized brushing of the slabs in

P. Wiilknitz

1997-01-01

125

29 CFR 1915.134 - Abrasive wheels.  

Code of Federal Regulations, 2010 CFR

...mounted abrasive wheels used for external grinding shall be provided with safety guards...The maximum angular exposure of the grinding wheel periphery and sides shall...c) Cup type wheels used for external grinding shall be protected by either a...

2010-07-01

126

Evaluation and Treatment of Perioperative Corneal Abrasions  

PubMed Central

Purpose. To evaluate perioperative risk factors for corneal abrasion (CA) and to determine current care for perioperative CA in a tertiary care setting. Methods. Hospital-based, cross-sectional study. In Operating Room and Post-Anesthesia Care Units patients, a comparison of cases and controls was evaluated to elucidate risk factors, time to treatment, and most common treatments prescribed for corneal abrasions. Results. 86 cases of corneal abrasion and 89 controls were identified from the 78,542 surgical procedures performed over 2 years. Statistically significant risk factors were age (P = 0.0037), general anesthesia (P < 0.001), greater average estimated blood loss (P < 0.001), eyes taped during surgery (P < 0.001), prone position (P < 0.001), trendelenburg position (P < 0.001), and supplemental oxygen en route to and in the Post-Anesthesia Care Units (P < 0.001). Average time to complaint was 129 minutes. 94% of cases had an inpatient ophthalmology consult, with an average time to consult of 164 minutes. The most common treatment was artificial tears alone (40%), followed by combination treatment of antibiotic ointment and artificial tears (35.3%). Conclusions. Trendelenburg positioning is a novel risk factor for CA. Diagnosis and treatment of perioperative corneal abrasions by an ophthalmologist typically require three hours in the tertiary care setting. PMID:24672709

Segal, Kira L.; Fleischut, Peter M.; Kim, Charles; Levine, Ben; Faggiani, Susan L.; Banerjee, Samprit; Gadalla, Farida; Lelli, Gary J.

2014-01-01

127

Grit not grass: Concordant patterns of early origin of hypsodonty in Great Plains ungulates and Glires  

E-print Network

Grit not grass: Concordant patterns of early origin of hypsodonty in Great Plains ungulates amongst many herbivorous clades from a browsing diet of leaves to a grazing diet of grasses. Hypsodonty is traditionally linked with eating grass because of the contained phytoliths, silica

Benton, Michael

128

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

129

Hydroxyapatite and fluorapatite coatings on dental screws: effects of blast coating process and biological response.  

PubMed

This paper describes the deposition of hydroxyapatite (HA) and fluorapatite (FA) onto titanium dental screws using a novel ambient temperature coating technique named CoBlast. The process utilises a coating medium and a blast medium sprayed simultaneously at the substrate surface. The blast medium was a sintered apatite (sHA) and two particles sizes (<106 and <180 µm) were used to assess their influence on the coating process. The influence of the coating process on the coating composition, coating adhesion, screw morphology and screw microstructure was examined. XRD analysis revealed the coating crystallinity was the same as the original HA and FA feedstock powders. Examining the screw's morphology, the threads of the CoBlasted screws exhibited rounding compared to the unmodified screw. This is due to the abrasive nature of the CoBlast process. The degree of rounding was more significant for the screws blasted with the 180 µm sHA than the 106 µm sHA. The blast media particle size significantly influences the surface roughness of both the substrate and coating and the microstructure of the substrate. The screws did not exhibit any loss of coating after insertion into a model bone material, indicating that the coating was strongly adhered to the substrate. There was no statistically significant difference in cell attachment and cell morphology on the unmodified substrates compared to the coated substrates. In conclusion, the CoBlast process can be used to deposit HA and FA onto complex geometries such as dental screws. The choice of blast medium particle size influences the screws morphology. The coating process does not negatively impact on the cell attachment and morphology in vitro. PMID:25578701

Dunne, Conor F; Twomey, Barry; Kelly, Ciara; Simpson, Jeremy C; Stanton, Kenneth T

2015-01-01

130

Abrasive jet micro-machining of polymeric materials  

NASA Astrophysics Data System (ADS)

In the abrasive jet micro-machining (AJM) process, a jet of small particles is directed through an erosion resistant mask opening so that micro-sized features (i.e., micro-channels, holes, etc.) can be machined for the fabrication of micro-devices such as micro-fluidic and micro-electro-mechanical-systems (MEMS). Polymeric materials and elastomers have found applications in a wide variety of micro-devices. This thesis investigates the AJM of such materials, addressing the major challenges that must be overcome in order for the process to gain wider acceptance in industry. The thesis first presents a novel cryogenically assisted abrasive jet micro-machining (CAJM) technique that enables the micro-machining of elastomers such as polydimethylsiloxane (PDMS) that cannot be machined at room temperature. It was found that the erosion rate during CAJM is greatly increased, and the degree of particle embedment greatly decreased, compared to room temperature experiments. A finite element (FE) analysis was used to investigate the relationships between erosion, the heat transfer of the cooling jet and the resulting target temperature during the CAJM of channels in PDMS. The analysis illustrated the asymmetric nature of the cooling with much more cooling occurring towards the trailing edge of the jet. It was found that the predicted shape of the evolving machined surface profiles was improved significantly when a FE model was used to account for thermal distortion occurring during the CAJM process. An unwanted consequence of the AJM of polymeric materials was found to be particle embedding. Criteria leading to the embedding of spherical and angular particles in such materials were identified and modelled using rigid plastic analyses. It was found that the likelihood of embedding was proportional to the static coefficient of friction between the particle and the target for angular particles, and the depth of penetration for spherical particles. Scanning electron microscopy with EDX was used to measure the area coverage of embedded Al2O3 particles in polymers and elastomers, in order to evaluate various cleaning methods that were developed. It was found that glass bead blasting at 45° followed by the freezing technique was the best method to remove embedded particles, leading to 100% removal in some cases.

Hailu, Getu

131

The effect of bleaching on toothbrush abrasion of resin composites  

PubMed Central

Aim: This experimental study was designed to focus on the effects of bleaching on toothbrush abrasion in three types of composites with different filler size. Materials and Methods: Forty eight disks were prepared from three types of composite and divided into 6 groups. In the first three groups the abrasion test was done. The remaining groups were bleached and the abrasion test was performed. The weight of the samples before and after abrasion was measured. Statistical analysis was done with one-way ANOVA and Duncan test. Results: There was a significant difference in abrasion of composites with different filler size (P < 0.05). The most amount of abrasion was observed in Z100 after being bleached. An increase in abrasion was noticed in all three types of tested composite after bleaching. Conclusion: According to the findings, it is suggested to use a nano filled resin composite for restoration if the bleaching treatment is required. PMID:23349570

Hajizadeh, Hila; Ameri, Hamideh; Eslami, Samaneh; Mirzaeepoor, Behnam

2013-01-01

132

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

E-print Network

to the enrichment of the cereals in the raw stage. Non-enriched degermed corn meal and grits were obtain- ed from Texas mills. Part of each batch was enriched by adding a commercial mixture of vitamins and minerals such as millers use. Sour milk corn bread..., boiled grits and fried grits were prepared from both the enriched and the non-en- riched cereals. Only enriched corn meal was used for sweet milk corn bread, spoonbread, pone and mush. The prepara- tion of each dish according to a standardized recipe...

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

1952-01-01

133

Wheel Abrasion Experiment Conducted on Mars  

NASA Technical Reports Server (NTRS)

Sojourner rover showing Lewis' wheel abrasion experiment. The Mars Pathfinder spacecraft soft-landed on Mars on July 4, 1997. Among the many experiments on its small Sojourner rover are three technology experiments from the NASA Lewis Research Center, including the Wheel Abrasion Experiment (WAE). The WAE was designed, built, delivered, and operated on Mars by a team of engineers and scientists from Lewis' Photovoltaics and Space Environments Branch. This experiment collected data to assess wheel surface wear on the Sojourner. It used a specially designed rover wheel, with thin films (200 to 1000 angstroms) of aluminum, nickel, and platinum deposited on black, anodized aluminum strips attached to the rover's right center wheel. As the wheel spun in the Martian soil, a photovoltaic sensor monitored changes in film reflectivity. These changes indicated abrasion of the metal films by Martian surface material. Rolling wear data were accumulated by the WAE. Also, at frequent intervals, all the rover wheels, except the WAE test wheel, were locked to hold the rover stationary while the test wheel alone was spun and dug into the Martian regolith. These tests created wear conditions more severe than simple rolling. The WAE will contribute substantially to our knowledge of Martian surface characteristics. Marked abrasion would indicate a surface composed of hard, possibly sharply edged grains, whereas lack of abrasion would suggest a somewhat softer surface. WAE results will be correlated with ground simulations to determine which terrestrial materials behave most like those on Mars. This knowledge will enable a deeper understanding of erosion processes on Mars and the role they play in Martian surface evolution. Preliminary results show that electrostatic charging of the rover wheels sometimes caused dust to accumulate on the WAE wheel, making interpretation of the reflectance data problematic. If electrostatic charging is the mechanism for dust attraction, this indicates that the Martian dust has a size somewhat smaller than 40 microns in diameter. The WAE experiment has detected electrostatic charging in the Martian environment for the first time; however, under conditions when the wheel is relatively clean of Martian dust, flight data now indicate that abrasion has also been detected. Crude limits so far place the hardness of the Martian dust at harder than aluminum but softer than nickel, and place the grain size at somewhat smaller than 40 microns.

Ferguson, Dale C.

1998-01-01

134

Cryogenically assisted abrasive jet micromachining of polymers  

NASA Astrophysics Data System (ADS)

The abrasive jet micromachining (AJM) of elastomers and polymers such as polydimethylsiloxane (PDMS), acrylonitrile butadiene styrene (ABS) and polytetrafluoroethylene (PTFE) for use in micro-fluidic devices was found to be very slow or impossible at room temperature. To enhance the material removal rate in such materials, a stream of liquid nitrogen (LN2) was injected into the abrasive jet, cooling the target to cryogenic temperatures. Erosion rate measurements on the three polymeric materials (PDMS, ABS and PTFE) with and without the use of LN2 were compared along with the profiles of micromachined channels and holes. It was found that the use of LN2 cooling caused brittle erosion in PDMS, allowing it to be micromachined successfully. An erosion rate increase was also observed in PTFE and ABS at high and intermediate impact angles. The use of LN2 also was found to reduce particle embedding.

Getu, H.; Spelt, J. K.; Papini, M.

2008-11-01

135

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

136

Surface Experiment of Abrasive Water Jet Perforation  

Microsoft Academic Search

This article presents the experiment process and results of abrasive water jet perforation. This experiment was conducted in Kalamayi, China, Xinjiang Oilfield in October 2004. Referring to explosive perforation experiment, we made two cement cylinder samples with a diameter of 2.4 m, 1.2 m high, putting a 139.7 mm (5-1\\/2?) and a 177.8 mm (7?) casing sub in them, respectively.

Z. Huang; J. Niu; G. Li; X. Yuan; Y. Liu

2008-01-01

137

Circular Signs of the Rock Abrasion Tool  

NASA Technical Reports Server (NTRS)

This image was taken by Mars Exploration Rover Opportunity's front hazard-avoidance camera, providing a circular sign of the success of the rover's first grinding of a rock. The round, shallow hole seen in this image is on a rock dubbed 'McKittrick,' located in the 'El Capitan' area of the larger outcrop near Opportunity's landing site.

Opportunity used its rock abrasion tool to grind off a patch of rock 45.5 millimeters (1.8 inches) in diameter during the 30th martian day, or sol, of its mission (Feb. 23, 2004). The grinding exposed fresh rock for close inspection by the rover's microscopic imager and two spectrometers located on its robotic arm. The Honeybee Robotics team, which designed and operates the rock abrasion tool, determined the depth of the cut at 'McKittrick' to be 4.4 millimeters (0.17 inches) deep.

On sol 34 (Feb. 27, 2004), the rover is scheduled to grind into its second target on the 'El Capitan' area, a rock dubbed 'Guadalupe' in the upper middle part of this image. The rock abrasion tools on both Mars Exploration Rovers were supplied by Honeybee Robotics, New York, N.Y.

2004-01-01

138

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

139

Saugus Iron Works Blast Furnace  

USGS Multimedia Gallery

A view of the Saugus Iron Works blast furnace, which smelted the iron from limonite, an iron ore. The limonite formed in nearby bogs, and was heated in the blast furnace until the iron melted and ran out the bottom of the furnace....

140

HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM  

SciTech Connect

The purpose of the project is to increase the productivity and economics of existing vacuum blasting technology. This technology is used to remove radioactive contamination, PCB's and lead-base paint and provides worker and environmental protection by continuously recycling the blast media and the full containment of the dust generated in the process.

Dr. M.A. Ebadian

2000-01-13

141

Centrifugal shot blast system  

SciTech Connect

This report describes a demonstration of Concrete cleaning, Inc., modified centrifugal shot blast technology to remove the paint coating from concrete flooring. This demonstration is part of the Chicago Pile-5 (CP-5) Large-Scale Demonstration Project (LSDP) sponsored by the US Department of Energy (DOE), office of Science and Technology (OST), Deactivation and Decommissioning Focus Area (DDFA). The objective of the LSDP is to select and demonstrate potentially beneficial technologies at the Argonne National Laboratory-East (ANL) CP-5 Research Reactor. The purpose of the LSDP is to demonstrate that using innovative and improved decontamination and decommissioning (D and D) technologies from various sources can result in significant benefits, such as decreased cost and increased health and safety, as compared with baseline D and D technologies. Potential markets exist for the innovative centrifugal shot blast system at the following sites: Fernald Environmental Management Project, Los Alamos, Nevada, Oak Ridge Y-12 and K-25, Paducah, Portsmouth Gaseous Diffusion site, and the Savannah River Site. This information is based on a revision to the OST Linkage Tables dated August 4, 1997.

NONE

1998-02-01

142

Spectroscopy and Imaging Performance of the Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT)  

Microsoft Academic Search

LXeGRIT is a balloon-borne Compton telescope based on a liquid xenon time projection chamber (LXeTPC) for imaging cosmic gamma -rays in the energy band 0.2- 20 MeV. The detector, with 400 cm2 area and 7 cm drift gap, is filled with high purity LXe. Both ionization and scintillation light signals are detected to measure the energy deposits and the three

E. Aprile; V. Egorov; K.-L. Giboni; U. G. Oberlack; J. Kikuchi; K. Takizawa; P. P. Dunphy

2000-01-01

143

Liquid xenon gamma-ray imaging telescope (LXeGRIT) for medium energy astrophysics  

Microsoft Academic Search

As part of our ongoing research program to develop a liquid xenon gamma-ray imaging telescope (LXe-GRIT) for medium energy astrophysics, we have built a liquid xenon time projection chamber (LXeTPC) with a total volume of 10 liters and a sensitive are of 20 cm by 20 cm. The detector has been successfully tested with gamma-ray sources in the laboratory and

Elena Aprile; Valeri Egorov; Fang Xu; Edward L. Chupp; Philip Dunphy; Tadayoshi Doke; Jun Kikuchi; Gerald J. Fishman; Geoffrey N. Pendleton; Kimiaki Masuda; Toshisuke Kashiwagi

1996-01-01

144

Abrasive properties and wear resistance of some transition-metal carbonitrides  

Microsoft Academic Search

1.Microhardness, abrasive grain strength, and abrasive power are not reliable criteria of the wear resistance of abrasive tools in the grinding of materials at high speeds. An understanding must be obtained of the mechanism by which the abrasive and work materials react with each other in the contact zone.2.The abrasive power of most carbonitrides exceeds that of white electroco undum,

A. A. Adamovskii; A. I. Bezykornov; I. I. Bilyk

1974-01-01

145

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

146

Calibration and in-flight performance of the Compton telescope prototype LXeGRIT  

NASA Astrophysics Data System (ADS)

The Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT) is the first balloon-borne instrument developed to validate the concept of a monolithic detector with 3D imaging capability as a Compton telescope for MeV astrophysics. The geometrical area is about 350 cm 2, an order of magnitude smaller than that of COMPTEL and the thickness of sensitive LXe is 7 cm, of equivalent stopping power as COMPTEL D2 detector. The spectroscopic and imaging response of LXeGRIT has been fully characterized in calibration experiments on the ground and during balloon flight experiments. During its most successful flight campaign of 27 h from Ft Sumner, in Fall 2000, the LXeTPC was operated without any external shield. The ?-ray background, measured at float altitude in the 0.5-10 MeV energy band, is well explained by the known atmospheric ?-ray flux. Results on the LXeGRIT in-flight performance, effective area, minimum flux sensitivity and background level are presented in this paper.

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

2004-02-01

147

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

148

Abrasive wear of some high-carbon alloys  

Microsoft Academic Search

1.On encountering abrasives, carbides may be damaged by splitting off or scoring.2.Complex chromium carbides of elongated form are not highly resistant to abrasive substances.On encountering niobium and vanadium carbides of compact shape the abrasive particle is more often damaged.3.An increase in the wear resistance of alloys depends more on the area of the working surface occupied by the carbides than

V. S. Popov; G. I. Vasilenko; P. L. Nagornyi

1970-01-01

149

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

150

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

151

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

152

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

153

Blast investigation by fast multispectral radiometric analysis  

Microsoft Academic Search

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

2011-01-01

154

Building BLAST for Coprocessor Accelerators Using Macah  

E-print Network

Building BLAST for Coprocessor Accelerators Using Macah by Ben Weintraub A senior thesis submitted sequences is fun- damental to many research pursuits in biology and genetics. BLAST (Basic Local Alignment the performance of the BLAST algorithm is a problem of great interest. BLAST compares a single query sequence

Hauck, Scott

155

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

156

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

157

Modeling on mass abrasion of kinetic energy penetrator  

Microsoft Academic Search

An engineering model on mass abrasion of kinetic energy penetrator is presented to predict the nose shape and mass loss of the residual projectile after high-speed penetration into concrete. The experimental analysis indicates that the kinetic energy of penetrator (i.e., mass and velocity of projectile) and the hardness of aggregate of concrete significantly affect the mass abrasion of projectile. A

X. W. Chen; L. L. He; S. Q. Yang

2010-01-01

158

The use of primary abrasion in ageing Siskins Carduelis spinus  

Microsoft Academic Search

This paper presents information regarding the use of primary abrasion for ageing Siskins. 96% of the Siskins examined could be aged from the degree of primary wear, juvenile outer primaries usually being more abraded than adults. A four point scale was used to classify the degree of abrasion. This ageing technique may be useful for other species of passerines that

Alan Martin

1996-01-01

159

Machinability of Abrasion Resistance Cast Iron with PCBN Cutting Tools  

Microsoft Academic Search

Highly abrasion and erosive resistance materials are an important group of materials and has very wide applications in many industrial areas. The characteristic properties for this material include the castability and the superior wear resistance. The material, however, is in the group of hard-to-machine materials due to its abrasion to cutting tool and low thermal conductivity. In this article, the

J. M. Zhou; M. Andersson

2008-01-01

160

Investigation of material reliabilities under gaseous abrasive wearing conditions  

Microsoft Academic Search

plants the pneumatic systems undergo severe abrasion, which is characterized by being nonuniform and localized [1]. Local wearing is of primary significance in limiting the service life of pneumatic pipework. A method has been developed in the Moscow Institute of Chemical Engineering for determining the wearing rates of materials operating under gaseous abrasive wearing conditions, by directing a jet of

V. I. Krasnov; I. B. Zhilinskii

1973-01-01

161

Abrasion of 6 dentifrices measured by vertical scanning interference microscopy  

PubMed Central

Objectives The abrasion of dentifrices is well recognized to eliminate the dental plaque. The aims of this study were to characterize the abrasive powders of 6 dentifrices (3 toothpastes and 3 toothpowders) and to measure the abrasion on a test surface by Vertical Scanning Interference microscopy (VSI). Material and Methods Bright field and polarization microscopy were used to identify the abrasive particles on the crude dentifrices and after prolonged washes. Scanning electron microscopy and microanalysis characterized the shape and nature of the particles. Standardized and polished blocks of poly(methylmethacrylate) were brushed with a commercial electric toothbrush with the dentifrices. VSI quantified the mean roughness (Ra) and illustrated in 3D the abraded areas. Results Toothpastes induced a limited abrasion. Toothpowders induced a significantly higher roughness linked to the size of the abrasive particles. One powder (Gencix® produced a high abrasion when used with a standard testing weight. However, the powder is based on pumice particles covered by a plant homogenate that readily dissolves in water. When used in the same volume, or after dispersion in water, Ra was markedly reduced. Conclusion Light and electron microscopy characterize the abrasive particles and VSI is a new tool allowing the analysis of large surface of abraded materials. PMID:24212995

PASCARETTI-GRIZON, Florence; MABILLEAU, Guillaume; CHAPPARD, Daniel

2013-01-01

162

A Laboratory Method for Assessment of Dentrifrice Abrasivity  

Microsoft Academic Search

This is the report of the Laboratory Abrasion Committee of the American Dental Association (ADA) Dentifrice Program relative to specific methods to measure the in vitro abrasivity of dentifrices. This method was used in two collaborative studies with six participating laboratories. These studies were designed by the ADA Dentifrice Program Statistical Committee and their interpretations form a basis for recommendations

John J. Hefferren

1976-01-01

163

Particle motion and stain removal during simulated abrasive tooth cleaning  

Microsoft Academic Search

Stain removal from teeth is important both to prevent decay and for appearance. This is usually achieved using a filament-based toothbrush with a toothpaste consisting of abrasive particles in a carrier fluid. This work has been carried out to examine how these abrasive particles interact with the filaments and cause material removal from a stain layer on the surface of

R. Lewis; S. C. Barber; R. S. Dwyer-Joyce

2007-01-01

164

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

165

Improving the Abrasion Resistance of Technical Textiles with Vermiculite Dispersions  

Microsoft Academic Search

Coatings of vermiculite on fiberglass textiles have been shown to increase the service temperatures up to 1100°C. These materials have found use in applications including safety fabrics, safety clothing, and thermal insulation. In this article the abrasion resistance of textiles coated with vermiculite dispersions is studied. It is shown that these coatings can significantly improve the abrasion resistance of fiberglass

C. C. Ou; D. G. Pickering

1991-01-01

166

Abrasive water jet machining of glass with stagnation effect  

Microsoft Academic Search

Abrasive water jet processes of glass are presented for crack-free machining of micro grooves and fluid polishing of micro channels with CFD analysis. In machining of the micro grooves, the abrasive is supplied to flow through intended machining area using the tapered masks. Stagnation under the jet and the horizontal flow on the machining area are controlled to generate crack-free

T. Matsumura; T. Muramatsu; S. Fueki

2011-01-01

167

Portable convertible blast effects shield  

DOEpatents

A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more frusto-conically-tapered telescoping rings operably connected to each other to convert between a telescopically-collapsed configuration for storage and transport, and a telescopically-extended upright configuration forming an expanded inner volume. In a first embodiment, the upright configuration provides blast effects shielding, such as against blast pressures, shrapnel, and/or fire balls. And in a second embodiment, the upright configuration provides ballistic shielding, such as against incoming weapons fire, shrapnel, etc. Each ring has a high-strength material construction, such as a composite fiber and matrix material, capable of substantially inhibiting blast effects and impinging projectiles from passing through the shield. And the set of rings are releasably securable to each other in the telescopically-extended upright configuration by the friction fit of adjacent pairs of frusto-conically-tapered rings to each other.

Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler, Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A. (Livermore, CA)

2011-03-15

168

Blasting casting to raise productivity  

SciTech Connect

Normally, surface mines employ draglines or truck and shovel systems to remove overburden. Blasting merely fragments and displaces the overburden enough to allow for easy digging. But during the past two decades, the effect of inflation and increased labor costs have encouraged unconventional methods of overburden removal. All of us are aware of the tremendous inflationary effects on costs of equipment, fuel, labor, interest, insurance, environmental compliance, etc. This has allowed the authors to take a new look at the use of explosives as an effective alternate method of overburden removal. This technique is known by several names, but basically blast casting or just casting best describes it. Other terms in vogue are explosive casting, controlled trajectory blasting, trajectory control blasting, and whatever terminology comes to mind.

Pilshaw, S.R.

1987-07-01

169

Portable convertible blast effects shield  

SciTech Connect

A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more telescoping cylindrical rings operably connected to each other to convert between a telescopically-collapsed configuration for storage and transport, and a telescopically-extended upright configuration forming an expanded inner volume. In a first embodiment, the upright configuration provides blast effects shielding, such as against blast pressures, shrapnel, and/or fire balls. And in a second embodiment, the upright configuration provides ballistic shielding, such as against incoming weapons fire, shrapnel, etc. Each ring has a high-strength material construction, such as a composite fiber and matrix material, capable of substantially inhibiting blast effects and impinging projectiles from passing through the shield. And the set of rings are releasably securable to each other in the telescopically-extended upright configuration, such as by click locks.

Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler,; Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A (Livermore, CA)

2010-10-26

170

Portable convertible blast effects shield  

DOEpatents

A rapidly deployable portable convertible blast effects shield/ballistic shield includes a set two or more telescoping cylindrical rings operably connected to each other to convert between a telescopically-collapsed configuration for storage and transport, and a telescopically-extended upright configuration forming an expanded inner volume. In a first embodiment, the upright configuration provides blast effects shielding, such as against blast pressures, shrapnel, and/or fire balls. And in a second embodiment, the upright configuration provides ballistic shielding, such as against incoming weapons fire, shrapnel, etc. Each ring has a high-strength material construction, such as a composite fiber and matrix material, capable of substantially inhibiting blast effects and impinging projectiles from passing through the shield. And the set of rings are releasably securable to each other in the telescopically-extended upright configuration, such as by click locks.

Pastrnak, John W. (Livermore, CA); Hollaway, Rocky (Modesto, CA); Henning, Carl D. (Livermore, CA); Deteresa, Steve (Livermore, CA); Grundler, Walter (Hayward, CA); Hagler, Lisle B. (Berkeley, CA); Kokko, Edwin (Dublin, CA); Switzer, Vernon A (Livermore, CA)

2007-05-22

171

Recycling ferrous-nickel slag in blast cleaning.  

PubMed

The aim of this study is the development of a procedure for the recycling of the ferrous-nickel slag that is widely used in open dry blast cleaning operations in Greek shipyards thus annually generating thousands of tons of blast cleaning waste. Laboratory tests were carried out, based on the reclamation of the material fraction with size a distribution within the range -1,400 + 150 microm, in order to determine the number of the effective uses (life cycles) of the abrasive material. It is demonstrated that the reclamation yield in the first three life cycles is more than 80%. Laboratory tests also proved that the recycled ferrous-nickel slag has properties comparable to the fresh material's ones in terms of particle size distribution, consumption and other physical-chemical properties. A semi-industrial recycling unit of used ferrous-nickel slag was also designed and installed in a Greek shipyard (Neorion New SA of Syros Shipyards). The operation of the semi-industrial recycling unit verified the conclusions resulting from the laboratory tests, and most important, it was proved profitable for the ship- PMID:12152895

Katsikaris, K; Voutsas, E; Magoulas, K; Andronikos, G; Stamataki, S

2002-06-01

172

Abrasion-erosion resistance of fiber reinforced concrete  

NASA Astrophysics Data System (ADS)

The concrete was used for repair of abrasion erosion damaged areas such as stilling basins, conduits, sluiceways, and discharge laterals in hydraulic structures. Thirteen concrete mixtures of three water cement ratios ranging from 0.40 to 0.72, each containing one of four different types of steel fibers, were tested. As is true of concrete without steel fibers, the abrasion erosion resistance of FRC increased with decrease in water cement ratio and consequent increase in compressive strength. The lengths of the fibers had very little effect on the abrasion erosion resistance, and the FRC containing collated and hooked fibers had better abrasion erosion resistance than the comparable concrete containing straight fibers. A comparison of the performance of FRC and concrete not containing fibers clearly showed that FRC was less resistant to abrasion erosion than concrete of the same aggregate type and water cement ratio without fibers.

Liu, T. C.; McDonald, J. E.

1981-11-01

173

Geology of the ``Turkana Grits'' in the Lariu range and Mt. Porr areas, southern Lake Turkana, Northwestern Kenya  

NASA Astrophysics Data System (ADS)

The onset of tectonism in the northern Kenya Rift is believed to be recorded by the deposition of immature, arkosic sandstones generally referred to as Turkana Grits. These sandstones have been interpreted by various workers as either Cretaceous or Miocene in age. Detailed re-mapping of the Turkana Grits in the Mount Porr (Kajong) area and a new mapping in the Lariu Range, both on the shores of Lake Turkana, coupled with interpretation of newly acquired seismic reflection profiles, have resulted in an integrated interpretation of the age and deposition of the Turkana Grits in these remote areas. In both areas the grits are predominantly coarse-grained, basement derrived sandstones deposited on a dissected basement topography by aggrading fluvial systems. Locally, syndepositional faulting has displaced and rotated some of the sandstones. Although the sediments are unfossiliferous in both areas, from their relationships with the basement and overlying volcanics, and their place within the regional tectonic context, it appears that the Turkana Grits in the southern Lake Turkana area are probably Oligo-Miocene deposits.

Wescott, W. A.; Morley, C. K.; Karanja, F. M.

1993-05-01

174

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

175

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

176

30 CFR 77.1304 - Blasting agents; special provisions.  

Code of Federal Regulations, 2010 CFR

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

2010-07-01

177

30 CFR 77.1304 - Blasting agents; special provisions.  

Code of Federal Regulations, 2012 CFR

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

2012-07-01

178

30 CFR 77.1304 - Blasting agents; special provisions.  

Code of Federal Regulations, 2014 CFR

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

2014-07-01

179

30 CFR 77.1304 - Blasting agents; special provisions.  

Code of Federal Regulations, 2011 CFR

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

2011-07-01

180

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...Circular 8179, “Safety Recommendations for Sensitized Ammonium Nitrate Blasting Agents,” or subsequent...

2013-07-01

181

Spectroscopy and Imaging Performance of the Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT)  

E-print Network

LXeGRIT is a balloon-borne Compton telescope based on a liquid xenon time projection chamber (LXeTPC) for imaging cosmic \\g-rays in the energy band of 0.2-20 MeV. The detector, with 400 cm$^2$ area and 7 cm drift gap, is filled with high purity LXe. Both ionization and scintillation light signals are detected to measure the energy deposits and the three spatial coordinates of individual \\g -ray interactions within the sensitive volume. The TPC has been characterized with repeated measurements of its spectral and Compton imaging response to \\g -rays from radioactive sources such as \

Aprile, E; Egorov, V; Giboni, K L; Oberlack, U G; Ventura, Sandro; Doke, T; Kikuchi, J; Takizawa, K; Chupp, E L; Dunphy, P P

2000-01-01

182

Spectroscopy and Imaging Performance of the Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT)  

E-print Network

LXeGRIT is a balloon-borne Compton telescope based on a liquid xenon time projection chamber (LXeTPC) for imaging cosmic \\g-rays in the energy band of 0.2-20 MeV. The detector, with 400 cm$^2$ area and 7 cm drift gap, is filled with high purity LXe. Both ionization and scintillation light signals are detected to measure the energy deposits and the three spatial coordinates of individual \\g -ray interactions within the sensitive volume. The TPC has been characterized with repeated measurements of its spectral and Compton imaging response to \\g -rays from radioactive sources such as \

E. Aprile; A. Curioni; V. Egorov; K. -L. Giboni; U. G. Oberlack; ; S. Ventura; ; T. Doke; J. Kikuchi; K. Takizawa; ; E. L. Chupp; P. P. Dunphy

2000-12-13

183

Hydro-abrasive erosion: Problems and solutions  

NASA Astrophysics Data System (ADS)

The number of hydro power plants with hydro-abrasive erosion is increasing worldwide. An overall approach is needed to minimize the impact of this phenomenon. Already at the start of the planning phase an evaluation should be done to quantify the erosion and the impact on the operation. For this, the influencing parameters and their impact on the erosion have to be known. The necessary information for the evaluation comprises among others the future design, the particle parameters of the water, which will pass the turbine, and the power plant owner's framework for the future operation like availability or maximum allowable efficiency loss, before an overhaul needs to be done. Based on this evaluation of the erosion, an optimised solution can then be found, by analysing all measures in relation to investments, energy production and maintenance costs as decision parameters. Often a more erosion-resistant design, instead of choosing the turbine design with the highest efficiency, will lead to higher revenue. The paper will discuss the influencing parameters on hydro-abrasive erosion and the problems to acquire this information. There are different optimisation possibilities, which will be shown in different case studies. One key aspect to reduce the erosion and prolong the operation time of the components is to coat all relevant parts. But it is very important that this decision is taken early in the design stage, as the design has to be adapted to the requirements of the coating process. The quality of coatings and their impact on the operation will be discussed in detail in the paper as due to the non-availability of standards many questions arise in projects.

Winkler, K.

2014-12-01

184

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

185

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

186

Friction and vibration of automotive brake pads containing different abrasive particles  

Microsoft Academic Search

Automotive brake friction materials with four different abrasive particles were investigated. The abrasives used in this study were commercial grade silicon carbide, zircon, quartz and magnesia. For microscopic understanding of friction and wear by abrasive particles in the brake friction material, single-particle scratch tests followed by scratch tests with multiple particles were performed first to understand the behavior of abrasive

Sung Soo Kim; Hee Jung Hwang; Min Wook Shin; Ho Jang

2011-01-01

187

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

188

Estimate of blast wave properties  

NASA Astrophysics Data System (ADS)

Correlation and TNT-equivalent models for UVCE blast wave properties are reviewed, and a model which estimates blast parameters from information on the cloud and its location and uses these parameters to evaluate damage is presented. The prediction model is based on calculations for an ideal, homogeneous, hemispherical, centrally ignited vapor cloud. In case of a deflagration an energy release rate function, equivalent to a certain flame path, is assumed. The results of these calculations (peak pressures as a function of distance) are used together with data for a detonating cloud. The positive phase duration is derived from separate calculations. The method estimates maximum effect, and it is not possible to predict when little or no blast will be generated.

Zeeuwen, J. P.

189

REMOVAL AND CONTAINMENT OF LEAD-BASED PAINT VIA NEEDLE SCALERS  

EPA Science Inventory

This report describes a comparative technical and economic evaluation of using a dustless needlegun system versus a conventional abrasive grit blasting system in the removal of lead-based paint from steel structures. he objective of the study was to comparatively analyze the oper...

190

REMOVAL AND CONTAINMENT OF LEAD-BASED PAINT VIA NEEDLE SCALERS  

EPA Science Inventory

This report describes a comparative technical and economic evaluation of using a dustless needlegun system versus a conventional abrasive grit blasting system in the removal of lead-based paint from steel structures. The objective of the study was to comparatively analyze the ope...

191

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

192

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

193

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

194

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

Code of Federal Regulations, 2014 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...

2014-01-01

195

21 CFR 872.6010 - Abrasive device and accessories.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Abrasive device and accessories. 872.6010 Section 872.6010...DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6010...

2012-04-01

196

21 CFR 872.6010 - Abrasive device and accessories.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Abrasive device and accessories. 872.6010 Section 872.6010...DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6010...

2013-04-01

197

29 CFR 1926.303 - Abrasive wheels and tools.  

Code of Federal Regulations, 2010 CFR

...wheels and tools. (a) Power. All grinding machines shall be supplied with sufficient...operation. (b) Guarding. (1) Grinding machines shall be equipped with...mounted abrasive wheels, used for external grinding, shall be provided with safety...

2010-07-01

198

Assessment of abrasion-assisted material removal in wire EDM  

Microsoft Academic Search

Machining speed and surface integrity continue to be issues of focus in current wire EDM research. In this light, the proof-of-concept of a hybrid wire EDM process that utilizes a wire embedded with electrically non-conducting abrasives is presented. Material removal in this novel process is realized through electrical erosion that is augmented by two-body abrasion. This is shown to bring

I. Menzies; P. Koshy

2008-01-01

199

Blast casting requires fresh assessment of methods  

SciTech Connect

The article says that because blast casting differs from conventional blasting, our ideas about explosive products, drilling, and initiating methods must change. The author discusses how to select a casting explosive and what factors are important in its selection. He also looks at how to determine the best blasthole diameter and burden blasting pattern.

Pilshaw, S.R.

1987-08-01

200

Simulation of Blast Waves with Headwind  

NASA Technical Reports Server (NTRS)

The blast wave resulting from an explosion was simulated to provide guidance for models estimating risks for human spacecraft flight. Simulations included effects of headwind on blast propagation, Blasts were modelled as an initial value problem with a uniform high energy sphere expanding into an ambient field. Both still air and cases with headwind were calculated.

Olsen, Michael E.; Lawrence, Scott W.; Klopfer, Goetz H.; Mathias, Dovan; Onufer, Jeff T.

2005-01-01

201

MOLECULAR CONTROL OF THE RICE BLAST DISEASE  

Technology Transfer Automated Retrieval System (TEKTRAN)

Rice blast disease caused by Magnaporthe grisea is a major constraint to rice production worldwide. The rice blast system is one of the best-characterized monocot model systems. The goal of this project is to understand molecular mechanisms of disease resistance using rice blast as a model system....

202

Law Vendor Coupon Co2 Blasting Tests  

SciTech Connect

The objectives identified in the test specification for the vendor CO2 blasting tests are to determine the ability of CO2 blasting to remove a measurable amount of surface material from Type 304L stainless steel and to identify the approximate blasting parameters for future testing on radioactively contaminated coupons.

May, C.G.

2003-07-25

203

Starch degradation and nutrition value improvement in corn grits by solid state fermentation technique with Coriolus versicolor  

PubMed Central

The study was conducted to evaluate effect of Coriolus versicolor mycelia on degrading starch and improving nutrition value in corn grits through solid state fermentation technique. The results showed that using soybean meal as a nitrogen source, ?-amylase secreted from C. versicolor expressed 407.25U/g of activity, leading to 45.15% of starch degraded. The activity grew with fermentation time until the 15th day, after that the amylase was deactivated rapidly. An orthogonal experiment designed for the study illustrated that degradation rate of starch in corn grits attained to maximum, 50.51%, when 100g of corn grits, added 16g of soybean meal, were fermented by C. versicolor for 12 days, in an initial pH 5.5. After fermenting, compared to the nonfermented control, contents of amino acids, total sugar, crude fat and crude protein were increased by 21.00%, 38.45%, 55.56%, 69.15% respectively. The significant improvement of nutrition value in corn grits is probably attributed to the intense metabolism of C. versicolor. PMID:24031762

Huang, Mian; Zhang, Song

2011-01-01

204

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

205

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

206

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

207

Effects of alumina air-abrasion and acidic priming agents on bonding between SUS XM27 steel and auto-polymerizing acrylic resin.  

PubMed

The purpose of this study was to evaluate the effects of functional monomers contained in the primers, as well as alumina particle abrasion on bonding between stainless steel and acrylic resin. SUS XM27 steel was primed with one of the following materials; Alloy Primer, Estenia Opaque Primer, M. L. Primer, and Super-Bond Liquid. Steel disks were either ground flat or alumina-blasted, primed with one of the four agents, and bonded with an acrylic resin (Unifast Trad). Bond strength was determined both before and after thermocycling (2,000 or 20,000 cycles). Among the four priming agents, the Alloy Primer and Estenia Opaque Primer, both of which contain 10-methacryloyloxydecyl dihydrogen phosphate (MDP), exhibited better bonding performance than the others. Alumina air-borne particle abrasion considerably improved the durability of bonding between the steel and the resin material. It can be concluded that alumina blasting followed by priming with an MDP agent is recommended for bonding the resin and SUS XM27 steel. PMID:17928724

Ishikawa, Yumi; Ohashi, Norihisa; Koizumi, Hiroyasu; Tanoue, Naomi; Nishiyama, Norihiro; Matsumura, Hideo

2007-09-01

208

Rock Abrasion Tool Exhibits the Deep Red Pigment of Mars  

NASA Technical Reports Server (NTRS)

During recent soil-brushing experiments, the rock abrasion tool on NASA's Mars Exploration Rover Spirit became covered with dust, as shown here. An abundance of iron oxide minerals in the dust gave the device a reddish-brown veneer. Investigators were using the rock abrasion tool to uncover successive layers of soil in an attempt to reveal near-surface stratigraphy. Afterward, remnant dirt clods were visible on both the bit and the brush of the tool. Designers of the rock abrasion tool at Honeybee Robotics and engineers at the Jet Propulsion Laboratory developed a plan to run the brush on the rock abrasion tool in reverse to dislodge the dirt and return the tool to normal operation. Subsequent communications with the rover revealed that the procedure is working and the rock abrasion tool remains healthy.

Spirit acquired this approximately true-color image with the panoramic camera on the rover's 893rd sol, or Martian day (July 8, 2006). The image combines exposures taken through three of the camera's filters, centered on wavelengths of 750 nanometers, 530 nanometers, and 430 nanometers.

2006-01-01

209

[Air and water contamination by road abrasion (author's transl)].  

PubMed

Owing to the abrasion of tar-containing or bituminous road surfaces particles are liberated which contain carcinophilic poly-aromatic hydrocarbons e.g. 3.4-benzpyrenes (BP). The effects of abrasion were determined by comparative measurements alongside a highway section of tar asphalt and one of concrete, both subjected to an identical traffic load. Airborne dust, sedimented dust near the ground and the degree of sewage pollution were measured. The wearing layer of the tar-asphalt surface consisted of TA16: max. grain size 16 mm; bonding agent TB 2000(containing 13 per cent tar pitch and 87 per cent bitumen). With a mean traffic load of 9000 vehicles per day abrasion liberated 15 mg 3.4-benzpyrene per month in winter and in summer 10 mg 3.4-benzpyrene per month and per 1 meter length of a two-laned highway. It was found that in the coarser dust particles the abrasion material containing 3.4-benzpyrene prevails. As a result, the tar asphalt abrasion in precipitated dust contained more than 50 per cent of total benzpyrene, while its share amounted even to 70 per cent of the total load in the floating fraction of waste water. PMID:1020536

Waibel, M

1976-12-01

210

Extragalactic Submillimetric Surveys with BLAST  

NASA Astrophysics Data System (ADS)

The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) has recently conducted an extragalactic submillimetric survey of the Chandra Deep Field South region of unprecedented size, depth, and angular resolution in three wavebands centered at 250, 350, and 500 ?m. BLAST wavelengths are chosen to study the Cosmic Infrared Background near its peak at 200 ?m. We find that most of the CIB at these wavelengths is contributed by galaxies detected at 24 ?m by the MIPS instrument on Spitzer, and that the source counts distribution shows a population with strongly evolving density and luminosity. These results anticipate what can be expected from the surveys that will be conducted with the SPIRE instrument on the Herschel space observatory.

Pascale, E.; Ade, P. A. R.; Bock, J. J.; Chapin, E. L.; Devlin, M. J.; Griffin, M.; Gundersen, J. O.; Halpern, M.; Hargrave, P. C.; Hughes, D. H.; Klein, J.; Marsden, G.; Martin, P. G.; Mauskopf, P.; Moncelsi, L.; Netterfield, C. B.; Ngo, H.; Olmi, L.; Patanchon, G.; Rex, M.; Scott, D.; Semisch, C.; Thomas, N.; Truch, M. D. P.; Tucker, C.; Tucker, G. S.; Viero, M. P.; Wiebe, D. V.

211

Developments in blast fragmentation measurement  

SciTech Connect

The digital image analysis program WipFrag has been developed under contract to INCO for use in quality control of underground blasting operations. This paper outlines the relevance of fragmentation to underground mining, the hardware and photography requirements, and key features and operating principles of the software. The science of granulometry offers a wide choice of statistics relating to the size and shape of fragments and the fabric and geometry of the rockpile. From these the authors have chosen to represent size distribution by the mass median diameter and the Rosin-Rammler coefficients. Fragment shape is measured by practical sphericity, a useful index to the slabbiness of the rock, which is often a factor in increased costs for loading, transportation and crushing. Concepts of resolution and accuracy are reviewed as they apply to digital image analysis systems. A method of calibration is described, using sieved crushed rock standards that simulate a range of rockpile uniformity conditions. Alternative zoom-merge procedures that combine images at various scales of magnification are expected to replace the empirical methods. Further research into blast optimization will require quantification of the triangular relationship between rock quality, blast parameters, and fragmentation statistics. Any one of these can be predicted knowing the other two, thus suggesting a new approach to measurement of rock mass quality. Routine fragmentation measurements might therefore give early warning of the need for modifications in stope spans, pit wall angles, and ground reinforcement and stabilization systems. Applications to measurement of rockfalls and rockbursts are also proposed.

Franklin, J.A. [Franklin Geotechnical Ltd., Orangeville, Ontario (Canada); [Univ. of Waterloo, Ontario (Canada); Maerz, N.H.; Santamarina, J.C. [Univ. of Waterloo, Ontario (Canada)

1995-12-31

212

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

213

Aeolian abrasion on Venus: Preliminary results from the Venus simulator  

NASA Astrophysics Data System (ADS)

The role of atmospheric pressure on aeolian abrasion was examined in the Venus Simulator with a constant temperature of 737 K. Both the rock target and the impactor were fine-grained basalt. The impactor was a 3 mm diameter angular particle chosen to represent a size of material that is entrainable by the dense Venusian atmosphere and potentially abrasive by virtue of its mass. It was projected at the target 10 to the 5 power times at a velocity of 0.7 m/s. The impactor showed a weight loss of approximately 1.2 x 10 to the -9 power gm per impact with the attrition occurring only at the edges. Results from scanning electron microscope analysis, profilometry, and weight measurement are summarized. It is concluded that particles can incur abrasion at Venusian temperatures even with low impact velocities expected for Venus.

Marshall, J. R.; Greeley, Ronald; Tucker, D. W.; Pollack, J. B.

1987-05-01

214

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

215

Compton scattering sequence reconstruction algorithm for the liquid xenon gamma-ray imaging telescope (LXeGRIT)  

E-print Network

The Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT) is a balloon born experiment sensitive to \\g -rays in the energy band of 0.2-20 MeV. The main detector is a time projection chamber filled with high purity liquid xenon (LXeTPC), in which the three-dimensional location and energy deposit of individual \\g -ray interactions are accurately measured in one homogeneous volume. To determine the \\g -ray initial direction (Compton imaging), as well as to reject background, the correct sequence of interactions has to be determined. Here we report the development and optimization of an algorithm to reconstruct the Compton scattering sequence and show its performance on Monte Carlo events and LXeGRIT data.

Oberlack, U G; Curioni, A; Egorov, V; Giboni, K L

2000-01-01

216

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.

Christopher Griffith

217

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

218

Preliminary results from the 1999 balloon flight of the Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT)  

Microsoft Academic Search

LXeGRIT is a balloon-borne Compton telescope employing a large volume liquid xenon time projection chamber (LXe-TPC) as the central (gamma) -ray detector. It is designed to image (gamma) - rays in the energy range of approximately 200 keV to 20 MeV, with an angular resolution of about 3 degrees (1 sigma) at 2 MeV, within a field-of-view (FOV) of about

Elena Aprile; Uwe G. Oberlack; Alessandro Curioni; Valeri Egorov; Karl-Ludwig Giboni; Sandro Ventura; Tadayoshi Doke; Jun Kikuchi; Kyoko Takizawa; Edward L. Chupp; Philip P. Dunphy

2000-01-01

219

An Experimental Study on the Fabrication of Glass-based Acceleration Sensor Body Using Micro Powder Blasting Method  

PubMed Central

This study investigated the feasibility of the micro powder blasting technique for the micro fabrication of sensor structures using the Pyrex glass to replace the existing silicon-based acceleration sensor fabrication processes. As the preliminary experiments, the effects of the blasting pressure, the mass flow rate of abrasive and the number of nozzle scanning times on erosion depth of the Pyrex and the soda lime glasses were examined. From the experimental results, optimal blasting conditions were selected for the Pyrex glass machining. The dimensions of the designed glass sensor was 1.7×1.7×0.6mm for the vibrating mass, and 2.9×0.7×0.2mm for the cantilever beam. The machining results showed that the dimensional errors of the machined glass sensor ranged from 3 ?m in minimum to 20 ?m in maximum. These results imply that the micro powder blasting method can be applied for the micromachining of glass-based acceleration sensors to replace the exiting method.

Park, Dong-Sam; Yun, Dae-Jin; Cho, Myeong-Woo; Shin, Bong-Cheol

2007-01-01

220

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

221

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

222

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

223

30 CFR 75.1310 - Explosives and blasting equipment.  

Code of Federal Regulations, 2014 CFR

...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

224

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

225

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

226

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

227

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

228

Correlating field and laboratory rates of particle abrasion, Rio Medio, Sangre de Cristo Mountains, New Mexico  

Microsoft Academic Search

River bed sediments commonly fine downstream due to a combination of particle abrasion, selective transport of finer grains, and fining of the local sediment supply from hillslopes and tributaries. Particle abrasion rates can be directly measured in the laboratory using tumbling barrels and annular flumes, however, scaling experimental particle abrasion rates to the field has proven difficult due to the

P. J. Polito; L. S. Sklar

2006-01-01

229

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

230

Modeling of SingleParticle Impact in Abrasive Water Jet Machining  

Microsoft Academic Search

This work presents a study on the abrasive water jet (AWJ) machining. An explicit finite element analysis (FEA) of single abrasive particle impact on stainless steel 1.4304 (AISI 304) is conducted. The abrasive water jet machining is modeled by FEA software ABAQUS\\/CAE. Shapes of craters in FEM simulation results were used and compared with the previous experimental and FEM works

S. Y. Ahmadi-Brooghani; H. Hassanzadeh; P. Kahhal

2007-01-01

231

Grooving micro-abrasion of polyamide 11 coated carbon steel tubulars for downhole application  

Microsoft Academic Search

The tribological properties of polyamide 11 coated carbon steel injector tubulars are reported using a commercially available micro-abrasion tester, as a candidate method for assessing the abrasive wear of polymer coatings. Efforts have been made to reproduce the wear mechanisms found to predominate in field simulated conditions. The wireline-based tests produced severe grooving abrasion of the polyamide 11 coating resulting

J. O Bello; R. J. K Wood

2003-01-01

232

BLAST Autonomous Daytime Star Cameras  

E-print Network

We have developed two redundant daytime star cameras to provide the fine pointing solution for the balloon-borne submillimeter telescope, BLAST. The cameras are capable of providing a reconstructed pointing solution with an absolute accuracy camera combines a 1 megapixel CCD with a 200 mm f/2 lens to image a 2 degree x 2.5 degree field of the sky. The instruments are autonomous. An internal computer controls the temperature, adjusts the focus, and determines a real-time pointing solution at 1 Hz. The mechanical details and flight performance of these instruments are presented.

Marie Rex; Edward Chapin; Mark J. Devlin; Joshua Gundersen; Jeff Klein; Enzo Pascale; Donald Wiebe

2006-05-01

233

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

234

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

235

IMPROVING FATIGUE STRENGTH OF METALS USING ABRASIVE WATERJET PEENING  

Microsoft Academic Search

Abrasive waterjet (AWJ) peening has been proposed as a viable method of surface treatment for metal orthopedic devices. In this study the influence of AWJ peening on the compressive residual stress, surface texture and fatigue strength of a stainless steel (AISI 304) and titanium (Ti6Al4V) alloy were studied. A design of experiments (DOE) and an analysis of variance (ANOVA) were

D. Arola; A. E. Alade; W. Weber

2006-01-01

236

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

237

Industrial cooling tower fan blade having abrasion resistant leading edge  

Microsoft Academic Search

This patent describes a glass fiber reinforced, synthetic resin fan blade for large diameter industrial water cooling tower fans, wherein the outer body portion of the blade is constructed of a thermoset resin and has upper and lower surfaces of which a part thereof define an elongated leading which would be subject to abrasion deterioration during use of the blade.

L. F. Burdick; S. E. Mayes

1992-01-01

238

Abrasion and sliding friction of thermal spray coatings  

NASA Astrophysics Data System (ADS)

Thermal spray cermet and metallic coatings are widely applied for abrasion and friction control in a variety of industries. In this work, the abrasion and friction behavior of WC-Co coatings has been examined in relation to their carbide size and distribution, and anisotropic mechanical properties. In addition, the friction behavior of molybdenum based coatings has been examined in relation to their surface and sub-surface wear mechanisms. These two material systems represent a wide variety of cermet and metallic coatings. For WC-Co coatings, indentation methods have been used to quantify their in-plane fracture behavior, in a modification of the indentation fracture toughness measurement technique used for sintered WC-Co. Such modification was necessitated by short crack growth in the out-of-plane direction of coating cross-sections. It has been shown that carbide size distribution and cobalt content in the starting powders affect the resultant coating's Wsb2C content, in-plane fracture behavior and abrasion rate. A correlation was found between the normalized abrasion rate (NAR) of the coatings and a combined microstructure/mechanical property parameter, termed the "abrasion" parameter. This parameter includes the applied stress, in-plane crack length, mean carbide size and distribution, binder content and hardness of the coatings. A plot has been produced between the NAR and abrasion parameter. This plot can be used to estimate the NAR of WC-Co coatings whose abrasion parameter values lie between 0.33×10sp{-6} and 99.63×10sp{-6}\\ ?msp{-1}, as calculated in this work. For molybdenum-based coatings, their sliding wear and friction behavior has been compared with that of sintered molybdenum. The origin of the various stages in the time-dependent friction behavior of these materials has been qualitatively explained on the basis of their sub-surface failure mechanisms and surface wear mechanisms. The sub-surface failure mechanisms in thermal spray coatings include lamellar and inter-lamellar fracture and, hence, are different from monolithic materials. The surface wear in the coatings, however, occurs via mechanisms commonly observed in monolithic materials, e.g., asperity interlocking and deformation, plowing and adhesion. The origin of friction in thermal spray coatings is found to be strongly dependent on their lamellar and inter-lamellar strength.

Usmani, Saifi

239

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

2013-04-01

240

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

2011-04-01

241

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

2012-04-01

242

Brushing abrasion of luting cements under neutral and acidic conditions.  

PubMed

Four resin based materials (Compolute Aplicap, ESPE; Variolink Ultra, Vivadent; C&B Metabond, Parkell and Panavia 21, Kuraray), two carboxylate cements (Poly-F Plus, Dentsply DeTrey and Durelon Maxicap, ESPE), two glass-ionomer cements (Fuji I, GC and Ketac-Cem Aplicap, ESPE), one resin-modified glass ionomer cement (Vitremer, 3M) one polyacid-modified resin composite (Dyract Cem, Dentsply DeTrey) and one zinc phosphate cement (Harvard, Richter & Hoffmann) were investigated according to their brushing resistance after storage in neutral and acidic buffer solutions. For this purpose 24 cylindrical acrylic molds were each filled with the materials. After hardening, the samples were stored for seven days in 100% relative humidity and at 37 degrees C. Subsequently, they were ground flat and polished. Then each specimen was covered with an adhesive tape leaving a 4 mm wide window on the cement surface. Twelve samples of each material were stored for 24 hours in a buffer solution with a pH of 6.8. The remaining 12 samples were placed in a buffer with a pH of 3.0. All specimens were then subjected to a three media brushing abrasion (2,000 strokes) in an automatic brushing machine. Storage and brushing were performed three times. After 6,000 brushing strokes per specimen, the tape was removed. Brushing abrasion was measured with a computerized laser profilometer and statistically analyzed with ANOVA and Tukey's Standardized Range Test (p < or = 0.05). The highest brushing abrasion was found for the two carboxylate cements. The lowest brushing abrasion was found for one resin based material, Compolute Aplicap. With the exception of three resin-based materials, a lower pH led to a higher brushing abrasion. PMID:11203860

Buchalla, W; Attin, T; Hellwig, E

2000-01-01

243

Blast-related traumatic brain injury.  

PubMed

A bomb blast may cause the full severity range of traumatic brain injury (TBI), from mild concussion to severe, penetrating injury. The pathophysiology of blast-related TBI is distinctive, with injury magnitude dependent on several factors, including blast energy and distance from the blast epicentre. The prevalence of blast-related mild TBI in modern war zones has varied widely, but detection is optimised by battlefield assessment of concussion and follow-up screening of all personnel with potential concussive events. There is substantial overlap between post-concussive syndrome and post-traumatic stress disorder, and blast-related mild TBI seems to increase the risk of post-traumatic stress disorder. Post-concussive syndrome, post-traumatic stress disorder, and chronic pain are a clinical triad in this patient group. Persistent impairment after blast-related mild TBI might be largely attributable to psychological factors, although a causative link between repeated mild TBIs caused by blasts and chronic traumatic encephalopathy has not been established. The application of advanced neuroimaging and the identification of specific molecular biomarkers in serum for diagnosis and prognosis are rapidly advancing, and might help to further categorise these injuries. PMID:23884075

Rosenfeld, Jeffrey V; McFarlane, Alexander C; Bragge, Peter; Armonda, Rocco A; Grimes, Jamie B; Ling, Geoffrey S

2013-09-01

244

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

245

The Saugus Iron Works Blast Furnace  

USGS Multimedia Gallery

A view of the Saugus Iron Works blast furnace, which smelted the iron from limonite, an iron ore. The limonite formed in nearby bogs, and was heated in the blast furnace until the iron melted and ran out the bottom of the furnace. ...

246

Building BLAST for Coprocessor Accelerators Using Macah  

Microsoft Academic Search

Abstract The problem of detecting similarities between different genetic sequences is fun- damental to many,research pursuits in biology and genetics. BLAST (Basic Local Alignment and Search Tool) is the most commonly,used tool for identi- fying and assessing the significance of such similarities. With the quantity of available genetic sequence data rapidly increasing, improving the performance of the BLAST algorithm is

Ben Weintraub

247

PROTECTIVE DESIGNS FOR BLAST AND IMPACT THREATS  

Microsoft Academic Search

This paper describes methods for designing and implementing protective technologies for improving the blast and impact resistance of buildings. A protection plan for buildings may include designing blast-resistant columns, walls, and windows; other elements of security may also play a major part, including physical security measures such as: anti-ram barriers and fencing to demarcate a protective perimeter; features such as

J. E. Crawford

248

Earthquake Engineering Mitigation of Blast Loading  

E-print Network

Earthquake Engineering Mitigation of Blast Loading Health Monitoring & Condition Assessment-structural building components, and visual sensing for dy- namic testing. Associate Professor Hyonny Kim comes to UC-fluidics and protective/energy absorbing materials provides synergy with the Department's ongoing work in blast mitigation

Wang, Deli

249

Highly concentrated foam formulation for blast mitigation  

SciTech Connect

A highly concentrated foam formulation for blast suppression and dispersion mitigation for use in responding to a terrorism incident involving a radiological dispersion device. The foam formulation is more concentrated and more stable than the current blast suppression foam (AFC-380), which reduces the logistics burden on the user.

Tucker, Mark D. (Albuquerque, NM); Gao, Huizhen (Albuquerque, NM)

2010-12-14

250

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

251

Back yard blasting on the quiet  

SciTech Connect

When R and F Coal Company of Ohio ''sweeps out the corners'' of many of its old sites, it often blasts ''literally in some family's back yard.'' Sequential blasting patterns allow for such work without unduly disturbing the residents. Four basic delay patterns are detailed in this article. Sequential timers, EB caps, HDP blast boosts, and bulk ANFO are used in the sequences. Electric blasting caps can be tested by means of a galvanometer for continuity and resistance whenever possible. The flexibility of programming firing times, in the four patterns, allows operators to fine tune the blasting techniques. End or back break are reduced, fragmentation is optimized, and vibration is held to a minimum.

Chironis, N.P.

1983-06-01

252

Solid Lubrication Fundamentals and Applications. Chapter 5; Abrasion: Plowing and Cutting  

NASA Technical Reports Server (NTRS)

Chapter 5 discusses abrasion, a common wear phenomenon of great economic importance. It has been estimated that 50% of the wear encountered in industry is due to abrasion. Also, it is the mechanism involved in the finishing of many surfaces. Experiments are described to help in understanding the complex abrasion process and in predicting friction and wear behavior in plowing and/or cutting. These experimental modelings and measurements used a single spherical pin (asperity) and a single wedge pin (asperity). Other two-body and three-body abrasion studies used hard abrasive particles.

Miyoshi, Kazuhisa

2001-01-01

253

Wind tunnel measurements of adobe abrasion by blown sand: profile characteristics in relation to wind velocity and sand flux  

Microsoft Academic Search

Blown sand causes various damages, such as extensive abrasion to crops, structural wear of facilities and buildings, and abrasion of soil clods and clayey materials generating fine particulate matter. In this study, experiments conducted in a straight-line blowing wind tunnel confirmed field observations and provided useful information for understanding abrasion profiles created by sand drift. Abrasion rates of 20 adobe

Liu Lian-You; Gao Shang-Yu; Shi Pei-Jun; Li Xiao-Yan; Dong Zhi-Bao

2003-01-01

254

Effects of grit roughness and pitch oscillations on the S814 airfoil  

SciTech Connect

Horizontal-axis wind turbine rotors experience unsteady aerodynamics when the rotor is yawed, when rotor blades pass through the support tower wake, and when the wind is gusting. An understanding of this unsteady behavior is necessary to assist in the design of new rotor airfoils. The rotors also experience performance degradation due to surface roughness. These surface irregularities are due to the accumulation of insect debris, ice, and/or the aging process. Wind tunnel studies that examine both the steady and unsteady behavior of airfoils can help define pertinent flow phenomena, and the resultant data can also be used to validate analytical computer codes. An S814 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory (OSU/AARL) 3 X 5 subsonic wind tunnel (3 X 5) under steady flow with both stationary model conditions and pitch oscillations. To study the extent of performance loss due to surface roughness, a leading edge grit roughness pattern (LEGR) was used to simulate leading edge contamination. After baseline cases were completed, the LEGR was applied for both steady state and model pitch oscillation cases. The Reynolds numbers for steady state conditions were 0.75, 1, 1.25 and 1.5 million, while the angle of attack ranged from -20{degrees} to +40{degrees}. While the model underwent pitch oscillations, data were acquired at Reynolds numbers of 0.75, 1, 1.25, and 1.5 million, at frequencies of 0.6, 1.2, and 1.8 Hz. Two sine wave forcing functions {+-}5.5{degrees} and {+-}10{degrees}, were used; at mean angles of attack of 8{degrees}, 14{degrees}, and 20{degrees}. For purposes herein, any reference to unsteady conditions means the model was in pitch oscillation.

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

1996-07-01

255

Effects of grit roughness and pitch oscillations on the S815 airfoil  

SciTech Connect

Horizontal axis wind turbine rotors experience unsteady aerodynamics due to wind shear when the rotor is yawed, when rotor blades pass through the support tower wake, and when the wind is gusting. An understanding of this unsteady behavior is necessary to assist in the calculation of rotor performance and loads. The rotors also experience performance degradation due to surface roughness. These surface irregularities are cause by the accumulation of insect debris, ice, and the aging process. Wind tunnel studies that examine both the steady and unsteady behavior of airfoils can help define pertinent flow phenomena, and the resultant data can be used to validate analytical computer codes. A S815 airfoil model was tested in The Ohio State University Aeronautical and Astronautical Research Laboratory (OSU/AARL) 3 x 5 subsonic wind tunnel (3 x 5) under steady flow and stationary model conditions, as well as with the model undergoing pitch oscillations. To study the possible extent of performance loss due to surface roughness, a standard grit pattern (LEGR) was used to simulate leading edge contamination. After baseline cases were completed, the LEGR was applied for both steady state and model pitch oscillation cases. The Reynolds numbers used for steady state conditions were 0.75, 1, 1.25, and 1.4 million, while the angle of attack ranged from {minus}20{degree} to +40{degree}. With the model undergoing pitch oscillations, data were acquired at Reynolds numbers of 0.75, 1, 1.25, and 1.4 million, at frequencies of 0.6, 1.2, and 1.8 Hz. Two sine wave forcing functions were used; {+-}5.5{degree} and {+-}10{degree}, at mean angles of attack of 8{degree}, 14{degree}, and 20{degree}. For purposes herein, any reference to unsteady conditions means that the model was in pitch oscillation about the quarter chord.

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

1996-07-01

256

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

257

Self-traveling robotic system for autonomous abrasive blast cleaning in double-hulled structures of ships  

E-print Network

oil tankers carrying crude oil, liquefied natural gas (LNG), or liquefied petroleum gas (LPG), lead, vessels such as very large crude oil carriers (VLCCs), bulk carriers (B/C), and liquefied natural gas

Kim, Jongwon

258

Abrasive blasting, a technique for the industrial decontamination of metal components and concrete blocks from decommissioning to unconditional release levels  

Microsoft Academic Search

When decommissioning nuclear installations, large quantities of metal components are produced as well as significant amounts of other radioactive materials, which mostly show low surface contamination. Having been used or having been brought for a while in a controlled area marks them as 'suspected material'. In view of the very high costs for radioactive waste processing and disposal, alternatives have

R. Gills; P. Lewandowski; B. Ooms; N. Reusen; W. Van Laer; R. Walthery

2007-01-01

259

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

260

LTC vacuum blasting machine (concrete): Baseline report  

SciTech Connect

The LTC shot blast technology was tested and is being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU`s evaluation of efficiency and cost, this report covers the evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The LTC 1073 Vacuum Blasting Machine uses a high-capacity, direct-pressure blasting system which incorporates a continuous feed for the blast media. The blast media cleans the surface within the contained brush area of the blast. It incorporates a vacuum system which removes dust and debris from the surface as it is blasted. The safety and health evaluation during the testing demonstration focused on two main areas of exposure: dust and noise. Dust exposure during maintenance activities was minimal, but due to mechanical difficulties dust monitoring could not be conducted during operation. Noise exposure was significant. Further testing for each of these exposures is recommended because of the outdoor environment where the testing demonstration took place. This may cause the results to be inaccurate. It is feasible that the dust and noise levels will be higher in an enclosed environment. In addition, other safety and health issues found were ergonomics, heat stress, tripping hazards, electrical hazards, lockout/tagout, and arm-hand vibration.

NONE

1997-07-31

261

Characterization of novel blast resistant genes for US rice breeding  

Technology Transfer Automated Retrieval System (TEKTRAN)

Blast resistance genes, such as Pi-ta, conveying resistance up to 8 common US races of the blast pathogen (Magnaporthe oryzae), have been used for 20 years in the US rice (Oryza sativa) industry. However, Pi-ta is susceptible to two known US races of blast. Race IE-1K has caused blast outbreaks in A...

262

Behavior of Silicone Sealants in Bomb Blast Mitigating Window Designs  

Microsoft Academic Search

The threat of terrorist attack impacts our lives every day. Because this threat is very real, we have seen the use of bomb blast mitigating window designs grow significantly in recent years. Effective bomb blast mitigating window designs allow the window system to withstand a moderate bomb blast without causing significant injury to building occupants from the blast itself or

Kenneth Yarosh; Gerald Braeuer; Sigurd Sitte

2002-01-01

263

Predicting the effectiveness of blast wall barriers using neural networks  

Microsoft Academic Search

Blast damage assessment of buildings and structural elements requires an accurate prediction of the blast loads in terms of the peak pressures and impulses. Blast loadings on structures have typically been evaluated using empirical relationships. These relationships assume that there are no obstacles between the explosive device and the target. If a blast barrier is used to protect personnel or

Alex M. Remennikov; Timothy A. Rose

2007-01-01

264

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

265

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

266

True Grit: Trait-level Perseverance and Passion for Long-term Goals Predicts Effectiveness and Retention among Novice Teachers  

PubMed Central

Background/Context Surprisingly little progress has been made in linking teacher effectiveness and retention to factors observable at the time of hire. The rigors of teaching, particularly in low-income school districts, suggest the importance of personal qualities that have so far been difficult to measure objectively. Purpose/Objective/Research Question/Focus of Study In this study, we examine the predictive validity of personal qualities not typically collected by school districts during the hiring process. Specifically, we use a psychological framework to explore how biographical data on grit, a disposition toward perseverance and passion for long-term goals, explains variance in novice teachers’ effectiveness and retention. Research Design In two prospective, longitudinal samples of novice teachers assigned to schools in low-income districts (N = 154 and N = 307, respectively), raters blind to outcomes followed a 7-point rubric to rate grit from information on college activities and work experience extracted from teachers’ résumés. We used independent-samples t-tests and binary logistic regression models to predict teacher effectiveness and retention from these grit ratings as well as from other information (e.g., SAT scores, college GPA, interview ratings of leadership potential) available at the time of hire. Conclusions/Recommendations Grittier teachers outperformed their less gritty colleagues and were less likely to leave their classrooms mid-year. Notably, no other variables in our analysis predicted either effectiveness or retention. These findings contribute to a better understanding of what leads some novice teachers to outperform others and remain committed to the profession. In addition to informing policy decisions surrounding teacher recruitment and development, this investigation highlights the potential of a psychological framework to explain why some individuals are more successful than others in meeting the rigorous demands of teaching. PMID:25364065

Robertson-Kraft, Claire; Duckworth, Angela Lee

2013-01-01

267

Experimental Investigations on Ice Bonded Abrasive Polishing of Copper Materials  

Microsoft Academic Search

In this article, an attempt is made to prepare an ice-bonded abrasive polishing (IBAP) tool, in situ, for ultrafine finishing of flat, Electrolytic Copper (EC)-grade copper specimen. Two different methods such as direct and layer-by-layer methods of freezing slurry were tried for preparation of the IBAP tool. Tools prepared by both these methods were characterized to analyze the distribution of

R. Mohan; N. Ramesh Babu

2010-01-01

268

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

269

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

270

An Upgraded Data Acquisition System for the Balloon-Borne Liquid Xenon Gamma-Ray Telescope LXeGRIT  

Microsoft Academic Search

LXeGRIT is a balloon-borne Compton telescope for MeV gamma-ray astrophysics,\\u000abased on a liquid xenon time projection chamber (LXe-TPC) with charge and light\\u000areadout. The first balloon flights in 1997 revealed limitations of the trigger\\u000aelectronics and the data acquisition (DAQ) system, leading to their upgrade.\\u000aNew electronics was developed to handle the xenon scintillation light trigger.\\u000aThe original processor

Elena Aprile; Alessandro Curioni; Karl-Ludwig Giboni; Uwe Oberlack; Sandro Ventura

2000-01-01

271

Abrasion of abutment screw coated with TiN  

PubMed Central

STATEMENT OF PROBLEM Screw loosening has been a common complication and still reported frequently. PURPOSE The purpose of this study was to evaluate abrasion of the implant fixture and TiN coated abutment screw after repeated delivery and removal with universal measuring microscope. MATERIAL AND METHODS Implant systems used for this study were Osstem and 3i. Seven pairs of implant fixtures, abutments and abutment screws for each system were selected and all the fixtures were perpendicularly mounted in liquid unsaturated polyesther with dental surveyor. After 20 times of repeated closing and opening test, the evaluation for the change of inner surface of implant and TiN-coated abutment screw, and weight loss were measured. Mann-Whitney test with SPSS statistical software for Window was applied to analyze the measurement of weight loss. RESULTS TiN-coated abutment screws of Osstem and 3i showed lesser loss of weight than non-coated those of Osstem and 3i (P < .05, Mann-Whitney test). CONCLUSION Conclusively, TiN coating of abutment screw showed better resistance to abrasion than titanium abutment screw. It was concluded that TiN coating of abutment screw would reduce the loss of preload with good abrasion resistance and low coefficient of friction, and help to maintain screw joint stability. PMID:21165263

Jung, Seok-Won; Son, Mee-Kyoung; Chung, Chae-Heon

2009-01-01

272

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

273

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

274

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

275

Critical distance for blast-resistant design  

NASA Astrophysics Data System (ADS)

Blast loads have, in the recent past, become important service loads for certain categories of structures. An important task in blast-resistant design is to make a realistic prediction of the blast pressures. The distance of explosion from the structure is an important datum, governing the magnitude and duration of the blast loads. The current practice is to choose some arbitrary distance for design purposes. This paper presents some results of analytical studies to show that such a notion is likely to be erroneous, particularly for tall and slender structures. The elements of the blast phenomenon are reviewed, before going into the formulations leading to the 'critical blast distance' at which the transient dynamic response rises to a maximum. Based on the principle of Mach stem growth and consequent transformation of the spherical shock front into cylindrical or plane shock front, an expression for the distance at which the structure is fully engulfed by the Mach region is derived. This is the distance at which the cumulative blast effect reaches a maximum, and hence can be identified as critical distance. To verify this theory, certain numerical experiments are conducted on structures of different heights and diameters, such as cylindrical towers, a chimney and a cooling tower. The results of these studies have convincingly proved the existence of the critical ground-zero distance at which the cumulative blast effect reaches a maximum. It is concluded that this critical distance should be used as the design distance particularly for tall structures. It is also advisable to use a realistic type of shock front and shock reflection coefficient, consistent with the height of Mach stem, incidence angle and pressure magnitude.

Dharaneepathy, M. V.; Rao, M. N. Keshava; Santhakumar, A. R.

1995-02-01

276

Patterns in Blast Injuries to the Hand  

Microsoft Academic Search

Blast injuries to the hand are not just a wartime phenomenon but also quite common in rural communities throughout northern\\u000a California. The purpose of this study is to review our experience with blast injuries in the community and review the most\\u000a common patterns in an attempt to identify the pathomechanics of the hand injury and the reconstructive procedures that are

Ron Hazani; Rudolf F. Buntic; Darrell Brooks

2009-01-01

277

Blast-Tube Cooling for Aircraft Generators  

Microsoft Academic Search

Established principles of hydraulics are used to develop and explain fundamentals of blast-tube cooling. It is shown that the pressure-volume curves of a blast tube can be determined by flight tests, and that the pressure-volume curve of a generator can be determined in the laboratory. From the two pressure-volume curves, the air-flow through the generator in flight can be predicted,

Cyril G. Veinott

1944-01-01

278

A study of the LXeGRIT detection efficiency for MeV gamma-rays during the 2000 balloon flight campaign  

NASA Astrophysics Data System (ADS)

LXeGRIT—Liquid Xenon Gamma-Ray Imaging Telescope—is the first prototype of a Compton telescope (CT) for MeV ?-ray astrophysics based on a LXe time projection chamber. One of the most relevant figures of merit for a CT is the detection efficiency for ?-rays, which depends on diverse contributions such as detector geometry and passive materials, trigger efficiency, dead time, etc. A detailed study of the efficiency of the LXeGRIT instrument, based both on laboratory measurements and Monte Carlo (MC) simulations, is presented in this paper.

Curioni, A.; Aprile, E.; Doke, T.; Giboni, K. L.; Kobayashi, M.; Oberlack, U. G.

2007-06-01

279

A Study of the LXeGRIT Detection Efficiency for MeV Gamma-Rays during the 2000 Balloon Flight Campaign  

E-print Network

LXeGRIT - Liquid Xenon Gamma-Ray Imaging Telescope - is the first prototype of a Compton telescope for \\MeV \\g-ray astrophysics based on a LXe time projection chamber. One of the most relevant figures of merit for a Compton telescope is the detection efficiency for \\g-rays, which depends on diverse contributions such as detector geometry and passive materials, trigger efficiency, dead time, etc. A detailed study of the efficiency of the LXeGRIT instrument, based both on laboratory measurements and Monte Carlo simulations, is presented in this paper.

Curioni, A; Doke, T; Giboni, K L; Kobayashi, M; Oberlack, U G

2007-01-01

280

A Study of the LXeGRIT Detection Efficiency for MeV Gamma-Rays during the 2000 Balloon Flight Campaign  

E-print Network

LXeGRIT - Liquid Xenon Gamma-Ray Imaging Telescope - is the first prototype of a Compton telescope for \\MeV \\g-ray astrophysics based on a LXe time projection chamber. One of the most relevant figures of merit for a Compton telescope is the detection efficiency for \\g-rays, which depends on diverse contributions such as detector geometry and passive materials, trigger efficiency, dead time, etc. A detailed study of the efficiency of the LXeGRIT instrument, based both on laboratory measurements and Monte Carlo simulations, is presented in this paper.

A. Curioni; E. Aprile; T. Doke; K. L. Giboni; M. Kobayashi; U. G. Oberlack

2007-02-09

281

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

282

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

283

Effects of mine blasting on residential structures  

SciTech Connect

Blasting is common in the coal industry to remove rock overburden so that the exposed coal can be mechanically excavated. The ground vibrations and air blast produced by blasting are often felt by residents surrounding the mines. There has been a trend for regulatory authorities, especially those concerned with the environment, to impose low limits on blast vibration levels in response to community pressure, based on human perception and response to vibration. This paper reports the findings of an extensive study on a house which was located adjacent to a coal mine. The house was monitored for over 1 year and was subjected to ground peak particle velocity (PPV) ranging from 1.5 to 222 mm/s. The house was instrumented with accelerometers to measure its dynamic response due to blasting and it was also monitored for cracks before and after each blast. Based on this study, ground motion amplifications along the height of the structure have been established. A simplified methodology presented in this paper has been used to estimate the ground PPV at which cracking is likely.

Gad, E.F.; Wilson, J.L.; Moore, A.J.; Richards, A.B. [Swinburne University of Technology, Hawthorn, Vic. (Australia). Faculty of Engineering & Industrial Science

2005-08-01

284

Building BLAST for Coprocessor Accelerators Using Macah  

E-print Network

The problem of detecting similarities between different genetic sequences is fundamental to many research pursuits in biology and genetics. BLAST (Basic Local Alignment and Search Tool) is the most commonly used tool for identifying and assessing the significance of such similarities. With the quantity of available genetic sequence data rapidly increasing, improving the performance of the BLAST algorithm is a problem of great interest. BLAST compares a single query sequence against a database of known sequences, employing a heuristic algorithm that consists of three stages arranged in a pipeline, such that the output of one stage feeds into the input of the next stage. Several recent studies have successfully investigated the use of Field-Programmable Gate Arrays (FPGAs) to accelerate the execution of the BLAST algorithm, focusing on the first and second stages, which account for the vast majority of the algorithms execution time. While these results are encouraging, translating algorithms like BLAST that contain somewhat complex and unpredictable control flow and data access patterns into versions suitable for implementation on coprocessor accelerators like FPGAs turns out to be quite difficult using currently available tools. Such architectures are usually programmed using Hardware Description Languages (HDLs), which are significantly more difficult to learn and use than standard programming languages. In this paper, an accelerated version of the BLAST algorithm is presented, written in a new language called Macah, which is designed to make the task of programming coprocessor accelerators easier for programmers familiar with the widely-known C language.

Ben Weintraub

2008-01-01

285

The effect of hydrogen peroxide on polishing removal rate in CMP with various abrasives  

NASA Astrophysics Data System (ADS)

The effect of hydrogen peroxide in chemical mechanical planarization slurries for shallow trench isolation was investigated. The various abrasives used in this study were ceria, silica, alumina, zirconia, titania, silicon carbide, and silicon nitride. Hydrogen peroxide suppresses the polishing of silicon dioxide and silicon nitride surfaces by ceria abrasives. The polishing performances of other abrasives were either unaffected or enhanced slightly with the addition of hydrogen peroxide. The ceria abrasives were treated with hydrogen peroxide, and the polishing of the work surfaces with the treated abrasive shows that the inhibiting action of hydrogen peroxide is reversible. It was found that the effect of hydrogen peroxide as an additive is a strong function of the nature of the abrasive particle.

Manivannan, R.; Ramanathan, S.

2009-01-01

286

New Experimental Rig to Investigate Abrasive–Corrosive Characteristics of Metals in Aqueous Media  

Microsoft Academic Search

A new tribometer to investigate a conjoint effect of three-body abrasion and corrosion has been developed. In this design,\\u000a a flat wear sample is loaded against a rotating cylindrical disc counterface and the abrasive slurry is delivered to the contact\\u000a interface. Capabilities of the newly developed tribometer have been assessed through conducting abrasion–corrosion tests involving\\u000a simultaneous electrochemical measurements. In this

M. Salasi; G. B. Stachowiak; G. W. Stachowiak

2010-01-01

287

Influence of molybdenum, vanadium, and niobium on the abrasion resistance of high-chromium cast iron  

Microsoft Academic Search

1.Alloying additions of 0.17–2.33% Mo in cast irons considerably improves (particularly in contact with quartz sand) their abrasive wear resistance. This is due to the improved resistance of their martensite matrix and carbides to brittle fracture when in contact with abrasive grains.2.Alloying additions of vanadium decrease the abrasive wear resistance of cast irons. This is related to the negative influence

N. Sh. Shadrov; L. G. Korshunov; V. P. Cheremnikh

1983-01-01

288

Gapped BLAST and PSI-BLAST: a new generation of protein database search programs  

Microsoft Academic Search

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

Stephen F. Altschul; Thomas L. Madden; Alejandro A. Schäffer; Jinghui Zhang; Zheng Zhang; Webb C. Miller; David J. Lipman

1997-01-01

289

Determination of Optimal Blast Parameters for Construction of Blast-Created Rock-Fill Dams  

Microsoft Academic Search

The building of dams intended for various purposes, including hydraulic engineering, using the caving of the soil rims of canyons by pin-point blasting at the dam site is a promising trend in dam construction in mountainous regions. There is positive domestic and foreign experience with the construction of blast-created dams and cofferdams (the cofferdam for the Nurek hydroelectric power plant,

M. B. Étkin; A. E. Azarkovich

2001-01-01

290

Blast Resistance and Damage Modelling of Fibre Metal Laminates to Blast Loads  

NASA Astrophysics Data System (ADS)

A robust and efficient computational model has been developed which is capable of modelling the dynamic non-linear behaviour of GLARE panels subjected to blast loadings. Numerical model validation have been performed considering case studies of GLARE panels subjected to a blast-type pressure pulse for which experimental data on the back-face deflection and post-damage observations were available. Excellent agreement of mid-point deflections and evidence of severe yield line deformation were shown and discussed against the performed blast tests. A further parametric study identified GLARE as a potential blast attenuating structure, exhibiting superior blast potential against monolithic aluminium plates. It was concluded that further work needed to be carried out to take into account the influence of geometry (cylindrical structures), pre-pressurisation effects and boundary conditions

Mohamed, Galal F. A.; Soutis, Costas; Hodzic, Alma

2012-06-01

291

Surface roughness and wear of resin cements after toothbrush abrasion.  

PubMed

Increased surface roughness and wear of resin cements may cause failure of indirect restorations. The aim of this study was to evaluate quantitatively the surface roughness change and the vertical wear of four resin cements subjected to mechanical toothbrushing abrasion. Ten rectangular specimens (15 × 5 × 4 mm) were fabricated according to manufacturer instructions for each group (n = 10): Nexus 3, Kerr (NX3); RelyX ARC, 3M ESPE (ARC); RelyX U100, 3M ESPE (U100); and Variolink II, Ivoclar/Vivadent (VL2). Initial roughness (Ra, µm) was obtained through 5 readings with a roughness meter. Specimens were then subjected to toothbrushing abrasion (100,000 cycles), and further evaluation was conducted for final roughness. Vertical wear (µm) was quantified by 3 readings of the real profile between control and brushed surfaces. Data were subjected to analysis of variance, followed by Tukey's test (p < 0.05). The Pearson correlation test was performed between the surface roughness change and wear (p < 0.05). The mean values of initial/final roughness (Ra, µm)/wear (µm) were as follows: NX3 (0.078/0.127/23.175); ARC (0.086/0.246/20.263); U100 (0.296/0.589/16.952); and VL2 (0.313/0.512/22.876). Toothbrushing abrasion increased surface roughness and wear of all resin cements tested, although no correlation was found between those variables. Vertical wear was similar among groups; however, it was considered high and may lead to gap formation in indirect restorations. PMID:25466330

Ishikiriama, Sérgio Kiyoshi; Ordońéz-Aguilera, Juan Fernando; Maenosono, Rafael Massunari; Volú, Fernanda Lessa Amaral; Mondelli, Rafael Francisco Lia

2015-01-01

292

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

293

Characterization of blasted austenitic stainless steel and its corrosion resistance  

NASA Astrophysics Data System (ADS)

It is known that the corrosion resistance of stainless steel is deteriorated by blasting, but the reason for this deterioration is not clear. A blasted austenitic stainless steel plate (JIS-SUS304) has been characterized with comparison to the scraped and non-blasted specimens. The surface roughness of the blasted specimen is larger than that of materials finished with #180 paper. A martensite phase is formed in the surface layer of both blasted and scraped specimens. Compressive residual stress is generated in the blasted specimen and the maximum residual stress is formed at 50 100 µm from the surface. The corrosion potentials of the blasted specimen and subsequently solution treated specimen are lower than that of the non-blasted specimen. The passivation current densities of the blasted specimens are higher those of the non-blasted specimen. The blasted specimen and the subsequently solution treated specimen exhibit rust in 5% sodium chloride (NaCl) solution, while the non-blasted specimen and ground specimen do not rust in the solution. It is concluded that the deterioration of corrosion resistance of austenitic stainless steel through blasting is caused by the roughed morphology of the surface.

Otsubo, F.; Kishitake, K.; Akiyama, T.; Terasaki, T.

2003-12-01

294

30 CFR 57.6404 - Separation of blasting circuits from power source.  

Code of Federal Regulations, 2014 CFR

...false Separation of blasting circuits from power source. 57...NONMETAL MINES Explosives Electric Blasting-Surface and Underground...6404 Separation of blasting circuits from power source. (a...power source to a blasting circuit shall be locked in the...

2014-07-01

295

29 CFR 1926.906 - Initiation of explosive charges-electric blasting.  

Code of Federal Regulations, 2010 CFR

...blasting circuits or power circuits in accordance with the electric blasting cap manufacturer's... (e) When firing a circuit of electric blasting caps, care...condition. (i) A power circuit used for firing electric blasting caps shall...

2010-07-01

296

30 CFR 56.6404 - Separation of blasting circuits from power source.  

Code of Federal Regulations, 2013 CFR

... Separation of blasting circuits from power source. 56...NONMETAL MINES Explosives Electric Blasting § 56.6404 Separation of blasting circuits from power source. ...power source to a blasting circuit shall be locked in...

2013-07-01

297

29 CFR 1926.906 - Initiation of explosive charges-electric blasting.  

Code of Federal Regulations, 2011 CFR

...blasting circuits or power circuits in accordance with the electric blasting cap manufacturer's... (e) When firing a circuit of electric blasting caps, care...condition. (i) A power circuit used for firing electric blasting caps shall...

2011-07-01

298

30 CFR 56.6404 - Separation of blasting circuits from power source.  

Code of Federal Regulations, 2014 CFR

... Separation of blasting circuits from power source. 56...NONMETAL MINES Explosives Electric Blasting § 56.6404 Separation of blasting circuits from power source. ...power source to a blasting circuit shall be locked in...

2014-07-01

299

30 CFR 56.6404 - Separation of blasting circuits from power source.  

Code of Federal Regulations, 2010 CFR

... Separation of blasting circuits from power source. 56...NONMETAL MINES Explosives Electric Blasting § 56.6404 Separation of blasting circuits from power source. ...power source to a blasting circuit shall be locked in...

2010-07-01

300

30 CFR 57.6404 - Separation of blasting circuits from power source.  

Code of Federal Regulations, 2011 CFR

...false Separation of blasting circuits from power source. 57...NONMETAL MINES Explosives Electric Blasting-Surface and Underground...6404 Separation of blasting circuits from power source. (a...power source to a blasting circuit shall be locked in the...

2011-07-01

301

30 CFR 57.6404 - Separation of blasting circuits from power source.  

Code of Federal Regulations, 2013 CFR

...false Separation of blasting circuits from power source. 57...NONMETAL MINES Explosives Electric Blasting-Surface and Underground...6404 Separation of blasting circuits from power source. (a...power source to a blasting circuit shall be locked in the...

2013-07-01

302

30 CFR 57.6404 - Separation of blasting circuits from power source.  

Code of Federal Regulations, 2012 CFR

...false Separation of blasting circuits from power source. 57...NONMETAL MINES Explosives Electric Blasting-Surface and Underground...6404 Separation of blasting circuits from power source. (a...power source to a blasting circuit shall be locked in the...

2012-07-01

303

29 CFR 1926.906 - Initiation of explosive charges-electric blasting.  

Code of Federal Regulations, 2014 CFR

...blasting circuits or power circuits in accordance with the electric blasting cap manufacturer's... (e) When firing a circuit of electric blasting caps, care...condition. (i) A power circuit used for firing electric blasting caps shall...

2014-07-01

304

29 CFR 1926.906 - Initiation of explosive charges-electric blasting.  

Code of Federal Regulations, 2013 CFR

...blasting circuits or power circuits in accordance with the electric blasting cap manufacturer's... (e) When firing a circuit of electric blasting caps, care...condition. (i) A power circuit used for firing electric blasting caps shall...

2013-07-01

305

30 CFR 56.6404 - Separation of blasting circuits from power source.  

Code of Federal Regulations, 2012 CFR

... Separation of blasting circuits from power source. 56...NONMETAL MINES Explosives Electric Blasting § 56.6404 Separation of blasting circuits from power source. ...power source to a blasting circuit shall be locked in...

2012-07-01

306

29 CFR 1926.906 - Initiation of explosive charges-electric blasting.  

Code of Federal Regulations, 2012 CFR

...blasting circuits or power circuits in accordance with the electric blasting cap manufacturer's... (e) When firing a circuit of electric blasting caps, care...condition. (i) A power circuit used for firing electric blasting caps shall...

2012-07-01

307

30 CFR 56.6404 - Separation of blasting circuits from power source.  

Code of Federal Regulations, 2011 CFR

... Separation of blasting circuits from power source. 56...NONMETAL MINES Explosives Electric Blasting § 56.6404 Separation of blasting circuits from power source. ...power source to a blasting circuit shall be locked in...

2011-07-01

308

30 CFR 57.6404 - Separation of blasting circuits from power source.  

Code of Federal Regulations, 2010 CFR

...false Separation of blasting circuits from power source. 57...NONMETAL MINES Explosives Electric Blasting-Surface and Underground...6404 Separation of blasting circuits from power source. (a...power source to a blasting circuit shall be locked in the...

2010-07-01

309

Decontamination apparatus and method. [Patent applications  

DOEpatents

This invention relates generally to the fabrication of fuel pin elements employed in nuclear reactors and, more particularly, to removing radioactive contamination disposed on the exterior of finally assembled fuel pins. A blast head includes 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, D.J.

1983-12-16

310

Blending of agglomerates into powders 1: Quantification of abrasion rate.  

PubMed

A very common situation in the pharmaceutical arena is that a small amount of cohesive drug substance needs to be distributed in a large bulk of free-flowing filler such as lactose. The key topic of attention is that aggregates of a cohesive drug substance need to be sufficiently broken up in an acceptable time-frame. This implies that there is need for a better mechanistic understanding of the blending process and the reduction in size of the aggregates. The purpose of this study is to obtain more insight in the mechanisms that lead to the break up of assemblies of powder particles in a moving powder bed. The break up of aggregates was studied by application of so-called brittle Calibrated Test Particles (bCTPs). These are well-defined aggregates with brittle fracture properties. The dominant mechanism of the break up of these aggregates is abrasion by multiple impacts. There is evidence of a relationship between strength (expressed as porosity) of the bCTPs and rate of abrasion. This is often a slow process and the rate is determined not only by the (mechanical) properties of the agglomerates and process conditions, but also by the particle size distribution of the bulk filler. PMID:20015470

Willemsz, Tofan A; Oostra, Wim; Hooijmaijers, Ricardo; de Vegt, Onno; Morad, Nasim; Vromans, Herman; Frijlink, Henderik W; Van der Voort Maarschalk, Kees

2010-03-15

311

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

312

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

313

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

314

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

315

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

316

Evolution of blast wave profiles in simulated air blasts: experiment and computational modeling  

NASA Astrophysics Data System (ADS)

Shock tubes have been extensively used in the study of blast traumatic brain injury due to increased incidence of blast-induced neurotrauma in Iraq and Afghanistan conflicts. One of the important aspects in these studies is how to best replicate the field conditions in the laboratory which relies on reproducing blast wave profiles. Evolution of the blast wave profiles along the length of the compression-driven air shock tube is studied using experiments and numerical simulations with emphasis on the shape and magnitude of pressure time profiles. In order to measure dynamic pressures of the blast, a series of sensors are mounted on a cylindrical specimen normal to the flow direction. Our results indicate that the blast wave loading is significantly different for locations inside and outside of the shock tube. Pressure profiles inside the shock tube follow the Friedlander waveform fairly well. Upon approaching exit of the shock tube, an expansion wave released from the shock tube edges significantly degrades the pressure profiles. For tests outside the shock tube, peak pressure and total impulse reduce drastically as we move away from the exit and majority of loading is in the form of subsonic jet wind. In addition, the planarity of the blast wave degrades as blast wave evolves three dimensionally. Numerical results visually and quantitatively confirm the presence of vortices, jet wind and three-dimensional expansion of the planar blast wave near the exit. Pressure profiles at 90° orientation show flow separation. When cylinder is placed inside, this flow separation is not sustained, but when placed outside the shock tube this flow separation is sustained which causes tensile loading on the sides of the cylinder. Friedlander waves formed due to field explosives in the intermediate-to far-field ranges are replicated in a narrow test region located deep inside the shock tube.

Chandra, N.; Ganpule, S.; Kleinschmit, N. N.; Feng, R.; Holmberg, A. D.; Sundaramurthy, A.; Selvan, V.; Alai, A.

2012-09-01

317

The Effect of a New Tissue-Adhesive Wound Dressing on the Healing of Traumatic Abrasions  

Microsoft Academic Search

Background: Octylcyanoacrylate is a new medical-grade adhesive with antimicrobial properties. It forms a thin, flexible, occlusive bandage. Objective: To determine the gross and histological effects of the spray bandage when treating abrasions. Methods: Abrasions were produced on the flanks of 18 albino guinea pigs and randomized to treatment with a control (Biobrane) or octylcyanoacrylate dressing. The wounds were assessed with

James Quinn; Laurie Lowe; Michelle Mertz

2000-01-01

318

ABRASION RESISTANCE OF CONCRETE AS INFLUENCED BY INCLUSION OF FLY ASH  

E-print Network

of cement replacements (50 and 70%) with an ASTM Class C fly ash. Abrasion tests were carried out using abrasion resistance of high-volume fly ash concrete. A reference plain portland cement concrete-term strength and durability of fly ash concrete are generally higher than that of the plain portland cement

Wisconsin-Milwaukee, University of

319

The effects of system and geometric parameters on abrasive water jet nozzle wear  

Microsoft Academic Search

Nozzle wear dependence on abrasive water jet system parameters and nozzle geometry is experimentally investigated. Experimental procedures for evaluating long term and accelerated nozzle wear are discussed. Accelerated wear tests are conducted to study the effects of nozzle length, inlet angle, diameter, orifice diameter, abrasive flow rate, and water pressure on wear. An empirical model for nozzle weight loss rate

Madhusarathi Nanduri; David G. Taggart; Thomas J. Kim

2002-01-01

320

Surface modification of nanocolloidal silica for use as polishing abrasive particles  

Microsoft Academic Search

A new type of abrasive particle for polishing the dielectric layer on silicon wafers has been synthesized by modifying colloidal silica with cerium ions. Cerium ions in active silicic acid were titrated into a basic solution at 100°C to modify the surface of the colloidal silica. The new abrasive particles are easily suspended in an aqueous medium. The removal rate

Ming-Shyong Tsai

2003-01-01

321

An investigation on kerf characteristics in abrasive waterjet cutting of layered composites  

Microsoft Academic Search

Layered composites are “difficult-to-machine” materials as it is inhomogeneous due to the matrix properties, fibre orientation, and relative volume fraction of matrix. Abrasive waterjet cutting has proven to be a viable technique to machine such materials compared to conventional machining. This paper presents an investigation on the kerf taper angle, an important cutting performance measure, generated by abrasive waterjet (AWJ)

D. K. Shanmugam; S. H. Masood

2009-01-01

322

A study of abrasive water jet machining process on glass\\/epoxy composite laminate  

Microsoft Academic Search

Surface roughness (Ra) and kerf taper ratio (TR) characteristics of an abrasive water jet machined surfaces of glass\\/epoxy composite laminate were studied. Taguchi's design of experiments and analysis of variance were used to determine the effect of machining parameters on Ra and TR. Hydraulic pressure and type of abrasive materials were considered as the most significant control factor in influencing

M. A. Azmir; A. K. Ahsan

2009-01-01

323

The effect of suture anchor design and orientation on suture abrasion: An in vitro study  

Microsoft Academic Search

Purpose: To evaluate the effects of suture anchor design and orientation on suture abrasion in a cyclic model. Type of Study: In vitro. Methods: Biomechanical studies have shown suture breakage to be a predominant mode of failure in a suture anchor repair construct. It is possible that suture abrasion during knot tying or in vivo cyclic loading may contribute to

Davide D. Bardana; Robert T. Burks; John R. West; Patrick E. Greis

2003-01-01

324

Abrasive wear properties of metal matrix composites produced by hot isostatic pressing  

Microsoft Academic Search

Steel matrix composites are an attractive choice for paper, pulp and mineral crushing industries because of their wear resistant properties. In this paper the abrasive wear properties of the tool steel matrix composites are studied. The rubber wheel abrasion tests were carried out using six different composites. The tool steel Ralloy ® WR6 was used as matrix material in all

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

325

The effect of footwear sole abrasion on the coefficient of friction on melting and hard ice  

Microsoft Academic Search

Footwear sole wear by natural use or artificial abrasion either increases or decreases slip resistance on floors with and without lubricant. The objectives of this paper were to study the effect of footwear sole abrasive wear on slip resistance on ice with respect to temperature, and to compare the slip resistance of abraded soles on melting and hard ice with

Chuansi Gao; John Abeysekera; Mikko Hirvonen; Carita Aschan

2003-01-01

326

Flexural fatigue and surface abrasion of Kevlar-29 and other high-modulus fibres  

Microsoft Academic Search

This investigation deals with some flexural fatigue and abrasion studies of Kevlar-29, glass and carbon fibres. The test methods included in the study are fatigue by pure flexing, buckling and rotation over a wire, and abrasion by rubbing against a rotating rod. Kevlar-29 fibres were found to perform well in these tests because they could survive the relatively high bending

J. W. S. Hearle; B. S. Wong

1977-01-01

327

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

328

30 CFR 57.6306 - Loading, blasting, and security.  

Code of Federal Regulations, 2011 CFR

...activities permitted within the blast site shall be those activities directly related to the blasting operation and the activities of surveying, stemming, sampling of geology, and reopening of holes, provided that reasonable care is exercised. Haulage...

2011-07-01

329

30 CFR 56.6306 - Loading, blasting, and security.  

Code of Federal Regulations, 2012 CFR

...activities permitted within the blast site shall be those activities directly related to the blasting operation and the activities of surveying, stemming, sampling of geology, and reopening of holes, provided that reasonable care is exercised. Haulage...

2012-07-01

330

30 CFR 56.6306 - Loading, blasting, and security.  

Code of Federal Regulations, 2013 CFR

...activities permitted within the blast site shall be those activities directly related to the blasting operation and the activities of surveying, stemming, sampling of geology, and reopening of holes, provided that reasonable care is exercised. Haulage...

2013-07-01

331

30 CFR 57.6306 - Loading, blasting, and security.  

Code of Federal Regulations, 2012 CFR

...activities permitted within the blast site shall be those activities directly related to the blasting operation and the activities of surveying, stemming, sampling of geology, and reopening of holes, provided that reasonable care is exercised. Haulage...

2012-07-01

332

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

333

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

334

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

335

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

336

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

337

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

338

VIEW FACING EAST, VIEW FROM RIVER OF BLAST FURNACE NO. ...  

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

VIEW FACING EAST, VIEW FROM RIVER OF BLAST FURNACE NO. 3. DORR THICKENER & ORE BRIDGE AT LEFT, HOT BLAST STOVES & DUST CATCHER CENTER, CAST HOUSE AT RIGHT. - Pittsburgh Steel Company, Monessen Works, Donner Avenue, Monessen, Westmoreland County, PA

339

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

340

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

341

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

342

30 CFR 57.20031 - Blasting underground in hazardous areas.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Blasting underground in hazardous areas. 57.20031... SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Miscellaneous § 57.20031 Blasting underground in hazardous areas. In...

2012-07-01

343

30 CFR 57.20031 - Blasting underground in hazardous areas.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Blasting underground in hazardous areas. 57.20031... SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Miscellaneous § 57.20031 Blasting underground in hazardous areas. In...

2010-07-01

344

30 CFR 57.20031 - Blasting underground in hazardous areas.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Blasting underground in hazardous areas. 57.20031... SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Miscellaneous § 57.20031 Blasting underground in hazardous areas. In...

2013-07-01

345

30 CFR 57.20031 - Blasting underground in hazardous areas.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 false Blasting underground in hazardous areas. 57.20031... SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Miscellaneous § 57.20031 Blasting underground in hazardous areas. In...

2014-07-01

346

30 CFR 57.20031 - Blasting underground in hazardous areas.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Blasting underground in hazardous areas. 57.20031... SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Miscellaneous § 57.20031 Blasting underground in hazardous areas. In...

2011-07-01

347

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

348

30 CFR 57.6605 - Isolation of blasting circuits.  

Code of Federal Regulations, 2011 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...

2011-07-01

349

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

350

30 CFR 56.6605 - Isolation of blasting circuits.  

Code of Federal Regulations, 2010 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...

2010-07-01

351

30 CFR 57.6605 - Isolation of blasting circuits.  

Code of Federal Regulations, 2012 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...

2012-07-01

352

30 CFR 56.6605 - Isolation of blasting circuits.  

Code of Federal Regulations, 2011 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...

2011-07-01

353

30 CFR 57.6605 - Isolation of blasting circuits.  

Code of Federal Regulations, 2010 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...

2010-07-01

354

30 CFR 56.6605 - Isolation of blasting circuits.  

Code of Federal Regulations, 2014 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...

2014-07-01

355

30 CFR 56.6605 - Isolation of blasting circuits.  

Code of Federal Regulations, 2012 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...

2012-07-01

356

30 CFR 57.6605 - Isolation of blasting circuits.  

Code of Federal Regulations, 2014 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...

2014-07-01

357

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

358

AZIMUTHAL VARIATION OF RADIATION OF SEISMIC ENERGY FROM CAST BLASTS  

E-print Network

the variation of vibration intensity at various angles (azimuths) from large cast blasts. These effects characteristics, blasting personnel can use this information to mitigate vibration effects on local structures could mitigate problems with vibration levels from future blasting operations. Regionally, the local

359

Nineteen-Foot Diameter Explosively Driven Blast Simulator  

Microsoft Academic Search

This report describes the 19-foot diameter blast tunnel at Sandia National Laboratories. The blast tunnel configuration consists of a 6 foot diameter by 200 foot long shock tube, a 6 foot diameter to 19 foot diameter conical expansion section that is 40 feet long, and a 19 foot diameter test section that is 65 feet long. Therefore, the total blast

MANUEL G

2001-01-01

360

Test of Some Hybrid Combinations to Rice Blast  

Technology Transfer Automated Retrieval System (TEKTRAN)

Rice blast disease caused by Magnaporthe oryzae is one of the most devastating rice diseases worldwide. Blast resistant cultivars are recognized as the most efficacious and economical way to control this disease. Genetic resistance to rice blast is generally governed by a few major genes, often in c...

361

VIEW LOOKING NORTH, VIEW OF BLAST FURNACE NO. 2 (LEFT) ...  

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

VIEW LOOKING NORTH, VIEW OF BLAST FURNACE NO. 2 (LEFT) SHARING THE SAME CAST HOUSE WITH BLAST FURNACE NO. 1. ORE BRIDGE & BLOWER HOUSE TO RIGHT, HULETT CAR DUMPER IS IN LEFT FOREGROUND. - Pittsburgh Steel Company, Monessen Works, Blast Furnace No. 1 & No. 2, Donner Avenue, Monessen, Westmoreland County, PA

362

Modelling blast loads on buildings in complex city geometries  

Microsoft Academic Search

This paper is concerned with an accurate prediction of the effects of adjacent structures on the blast loads on a building in urban terrain. Blast loadings on structures have typically been evaluated using empirical relationships. These relationships assume that there are no obstacles between the charge and the target. In real situations, the actual blast loads can either be reduced

Alex M. Remennikov; Timothy A. Rose

2005-01-01

363

Gram-range explosive blast scaling and associated materials response  

E-print Network

Gram-range explosive blast scaling and associated materials response M. J. Hargather1 , G. S. Laboratory-scale gram-range explosive blast testing of materials is shown to be feasible. Blast loading from directions is included. The promise of gram-range testing is to take on at least some of the burden now

Settles, Gary S.

364

An efficient square-root algorithm for BLAST  

Microsoft Academic Search

Bell Labs Layered Space-Time (BLAST) is a scheme for transmitting information over a rich-scattering wireless environment using multiple receive and transmit antennas. The main computational bottleneck in the BLAST algorithm is a “nulling and cancellation” step, where the optimal ordering for the sequential estimation and detection of the received signals is determined. To reduce the computational cost of BLAST, we

Babak Hassibi

2000-01-01

365

Glass-Bead Blasting Alters Antenna Surface  

NASA Technical Reports Server (NTRS)

Thermal-emissivity properties improved, and focal length adjusted. Experiments show gentle blasting with glass beads produces beneficial changes in macroscopic surface shapes and in microscopic surface features of lightweight microwave reflectors made of thin metal reflective surfaces on deformable substrates of aluminum honeycomb.

Fortenberry, James W.; Jilka, Richard L.; Kimmel, Boyce; Garcia, Ramon D.; Cofield, Richard E.; Klose, Gerhardt J.; O'Toole, Thomas

1987-01-01

366

Blast resistance of prismatic sandwich structures  

Microsoft Academic Search

Metallic sandwich panels have emerged as candidate blast resistant structures that can be tailored to contain damage from impulsive loads of the type typically generated by explosives. When such panels are impulsively loaded, the stresses imposed by the core on the front face, as well as those transmitted through the core, govern the response metrics: especially the center displacement, the

Enrico Ferri

2009-01-01

367

Air blast loading of a cylindrical body  

Microsoft Academic Search

Pressure measurements were performed on the surface of a cylinder in shock tube experiments and in free field tests. In shock tube measurements, pressure waves with a rather sharp profile were observed, with overpressures ranging from 0.2 to 2 bar. Unsteady gain coefficients were obtained for weak and moderately strong incident shocks. In free field tests, blast waves at the

W. Heilig

1981-01-01

368

Blast wave mitigation by dry aqueous foams  

NASA Astrophysics Data System (ADS)

This paper presents results of experiments and numerical modeling on the mitigation of blast waves using dry aqueous foams. The multiphase formalism is used to model the dry aqueous foam as a dense non-equilibrium two-phase medium as well as its interaction with the high explosion detonation products. New experiments have been performed to study the mass scaling effects. The experimental as well as the numerical results, which are in good agreement, show that more than an order of magnitude reduction in the peak overpressure ratio can be achieved. The positive impulse reduction is less marked than the overpressures. The Hopkinson scaling is also found to hold particularly at larger scales for these two blast parameters. Furthermore, momentum and heat transfers, which have the main dominant role in the mitigation process, are shown to modify significantly the classical blast wave profile and thereafter to disperse the energy from the peak overpressure due to the induced relaxation zone. In addition, the velocity of the fireball, which acts as a piston on its environment, is smaller than in air. Moreover, the greater inertia of the liquid phase tends to project the aqueous foam far from the fireball. The created gap tempers the amplitude of the transmitted shock wave to the aqueous foam. As a consequence, this results in a lowering of blast wave parameters of the two-phase spherical decaying shock wave.

Del Prete, E.; Chinnayya, A.; Domergue, L.; Hadjadj, A.; Haas, J.-F.

2013-02-01

369

Global efforts in managing rice blast disease  

Technology Transfer Automated Retrieval System (TEKTRAN)

Rice blast disease caused by the fungus Magnaporthe oryzae is a major destructive disease threatening global food security. Resistance (R) genes to M. oryzae are effective in preventing infections by strains of M. oryzae carry the corresponding avirulence (AVR) genes. Effectiveness of genetic resist...

370

External Resource: Having a Solar Blast  

NSDL National Science Digital Library

In Data Analysis and Measurement: Having a Solar Blast!, students will learn how NASA researchers study the Sun. They will learn how satellite technology plays a pivotal role in helping NASA researchers understand the Sun-Earth connection. Students will l

1900-01-01

371

BLAST: Building energy simulation in Hong Kong  

Microsoft Academic Search

The characteristics of energy use in buildings under local weather conditions were studied and evaluated using the energy simulation program BLAST-3.0. The parameters used in the energy simulation for the study and evaluation include the architectural features, different internal building heat load settings and weather data. In this study, mathematical equations and the associated coefficients useful to the industry were

Sai-Keung Fong

1999-01-01

372

Vehicle bomb blast effects and countermeasures  

Microsoft Academic Search

The impact of a vehicle bomb blast on a building can be determined by analyzing the: (1) over-pressure that the building structural elements can withstand, (2) standoff distance that can be enforced, and (3) potential damage from a specific amount of explosives detonated at an enforceable standoff distance. This paper is organized in three parts that address the potential effects

J. W. James; T. M. Wood; E. M. Kruse; J. D. Veatch

2001-01-01

373

Rice blast evaluation of newly introduced germplasm  

Technology Transfer Automated Retrieval System (TEKTRAN)

Genetic resistance to the rice blast fungus, Magnaporthe oryzae (anamorph Pyricularia grisea oryzae) was identified in newly introduced rice germplasm through quarantine when tested in artificially inoculated greenhouse and field nursery tests during the 2007 growing season. Of 229 accessions, 31 we...

374

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

375

BLAST: a more efficient report with usability improvements.  

PubMed

The Basic Local Alignment Search Tool (BLAST) website at the National Center for Biotechnology (NCBI) is an important resource for searching and aligning sequences. A new BLAST report allows faster loading of alignments, adds navigation aids, allows easy downloading of subject sequences and reports and has improved usability. Here, we describe these improvements to the BLAST report, discuss design decisions, describe other improvements to the search page and database documentation and outline plans for future development. The NCBI BLAST URL is http://blast.ncbi.nlm.nih.gov. PMID:23609542

Boratyn, Grzegorz M; Camacho, Christiam; Cooper, Peter S; Coulouris, George; Fong, Amelia; Ma, Ning; Madden, Thomas L; Matten, Wayne T; McGinnis, Scott D; Merezhuk, Yuri; Raytselis, Yan; Sayers, Eric W; Tao, Tao; Ye, Jian; Zaretskaya, Irena

2013-07-01

376

Patterns in blast injuries to the hand.  

PubMed

Blast injuries to the hand are not just a wartime phenomenon but also quite common in rural communities throughout northern California. The purpose of this study is to review our experience with blast injuries in the community and review the most common patterns in an attempt to identify the pathomechanics of the hand injury and the reconstructive procedures that are required. This is a retrospective study of blast injuries to the hand treated between 1978 and 2006. Medical records, X-rays, and photos were reviewed to compile standard patient demographics and characterize the injury pattern. Explosives were classified based on their rate of decomposition. Reconstructive solutions were reviewed and characterized based on whether damaged tissues were repaired or replaced. Sixty-two patients were identified with blast injuries to their hand. Patients were predominantly male (92%) with an average age of 27 years. Firecrackers were the most commonly encountered explosives. Thirty-seven patients were identified as holding a low explosive in their dominant hand and were used for characterization of the injury pattern. The apparent pattern of injury was hyperextension and hyperabduction of the hand and digits. Common injuries were metacarpophalangeal and interphalangeal joint hyperextension with associated soft tissue avulsion, hyperabduction at the web spaces with associated palmar soft tissue tears, and finger disarticulation amputations worse at radial digits. Given the mechanisms of injury with tissue loss, surgical intervention generally involved tissue replacement rather than tissue repair. Blast injuries to the hand represent a broad spectrum of injuries that are associated with the magnitude of explosion and probably, the proximity to the hand. We were able to identify a repetitive pattern of injury and demonstrate the predominant use for delayed tissue replacement rather than microsurgical repair at the acute setting. PMID:18780004

Hazani, Ron; Buntic, Rudolf F; Brooks, Darrell

2009-03-01

377

Distinguishing Realistic Military Blasts from Firecrackers in Mitigation Studies of Blast Induced Traumatic Brain Injury  

SciTech Connect

In their Contributed Article, Nyein et al. (1,2) present numerical simulations of blast waves interacting with a helmeted head and conclude that a face shield may significantly mitigate blast induced traumatic brain injury (TBI). A face shield may indeed be important for future military helmets, but the authors derive their conclusions from a much smaller explosion than typically experienced on the battlefield. The blast from the 3.16 gm TNT charge of (1) has the following approximate peak overpressures, positive phase durations, and incident impulses (3): 10 atm, 0.25 ms, and 3.9 psi-ms at the front of the head (14 cm from charge), and 1.4 atm, 0.32 ms, and 1.7 psi-ms at the back of a typical 20 cm head (34 cm from charge). The peak pressure of the wave decreases by a factor of 7 as it traverses the head. The blast conditions are at the threshold for injury at the front of the head, but well below threshold at the back of the head (4). The blast traverses the head in 0.3 ms, roughly equal to the positive phase duration of the blast. Therefore, when the blast reaches the back of the head, near ambient conditions exist at the front. Because the headform is so close to the charge, it experiences a wave with significant curvature. By contrast, a realistic blast from a 2.2 kg TNT charge ({approx} an uncased 105 mm artillery round) is fatal at an overpressure of 10 atm (4). For an injury level (4) similar to (1), a 2.2 kg charge has the following approximate peak overpressures, positive phase durations, and incident impulses (3): 2.1 atm, 2.3 ms, and 18 psi-ms at the front of the head (250 cm from charge), and 1.8 atm, 2.5 ms, and 16.8 psi-ms at the back of the head (270 cm from charge). The peak pressure decreases by only a factor of 1.2 as it traverses the head. Because the 0.36 ms traversal time is much smaller than the positive phase duration, pressures on the head become relatively uniform when the blast reaches the back of the head. The larger standoff implies that the headform locally experiences a nearly planar blast wave. Also, the positive phase durations and blast impulses are much larger than those of (1). Consequently, the blast model used in (1) is spatially and temporally very different from a military blast. It would be useful to repeat the calculations using military blast parameters. Finally, (1) overlooks a significant part of (5). On page 1 and on page 3, (1) states that (5) did not consider helmet pads. But pages pages 3 and 4 of (5) present simulations of blast wave propagation across an ACH helmeted head form with and without pads. (5) states that when the pads are present, the 'underwash' of air under the helmet is blocked when compared to the case without. (1) reaches this same conclusion, but reports it as a new result rather than a confirmation of that already found in (5).

Moss, W C; King, M J; Blackman, E G

2011-01-21

378

Influence of Corrosion on the Abrasion of Cutter Steels Used in TBM Tunnelling  

NASA Astrophysics Data System (ADS)

Abrasion on tunnel boring machine (TBM) cutters may be critical in terms of project duration and costs. Several researchers are currently studying the degradation of TBM cutter tools used for excavating hard rock, soft ground and loose soil. So far, the primary focus of this research has been directed towards abrasive wear. Abrasive wear is a very common process in TBM excavation, but with a view to the environment in which the tools are working, corrosion may also exert an influence. This paper presents a selection of techniques that can be used to evaluate the influence of corrosion on abrasion on TBM excavation tools. It also presents the influence of corrosion on abrasive wear for some initial tests, with constant steel and geomaterial and varying properties of the excavation fluids (soil conditioners, anti-abrasion additives and water). The results indicate that the chloride content in the water media greatly influences the amount of wear, providing evidence of the influence of corrosion on the abrasion of the cutting tools. The presence of conditioning additives tailored to specific rock or soil conditions reduces wear. However, when chloride is present in the water, the additives minimise wear rates but fail to suppress corrosion of the cutting tools.

Espallargas, N.; Jakobsen, P. D.; Langmaack, L.; Macias, F. J.

2015-01-01

379

Quantitative characterization of agglomerate abrasion in a tumbling blender by using the Stokes number approach.  

PubMed

Removal of microcrystalline cellulose agglomerates in a dry-mixing system (lactose, 100 M) predominantly occurs via abrasion. The agglomerate abrasion rate potential is estimated by the Stokes abrasion (StAbr) number of the system. The StAbr number equals the ratio between the kinetic energy density of the moving powder bed and the work of fracture of the agglomerate. Basically, the StAbr number concept describes the blending condition of the dry-mixing system. The concept has been applied to investigate the relevance of process parameters on agglomerate abrasion in tumbling blenders. Here, process parameters such as blender rotational speed and relative fill volumes were investigated. In this study, the StAbr approach revealed a transition point between abrasion rate behaviors. Below this transition point, a blending condition exists where agglomerate abrasion is dominated by the kinetic energy density of the powder blend. Above this transition point, a blending condition exists where agglomerates show (undesirable) slow abrasion rates. In this situation, the blending condition is mainly determined by the high fill volume of the filler. PMID:23250711

Willemsz, Tofan A; Nguyen, Tien Thanh; Hooijmaijers, Ricardo; Frijlink, Henderik W; Vromans, Herman; van der Voort Maarschalk, Kees

2013-03-01

380

LTC American`s, Inc. vacuum blasting machine: Baseline report  

SciTech Connect

The LTC shot blast technology was tested and is being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU`s evaluation of efficiency and cost, this report covers the evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The LTC 1073 Vacuum Blasting Machine uses a high-capacity, direct-pressure blasting system which incorporates a continuous feed for the blast media. The blast media cleans the surface within the contained brush area of the blast. It incorporates a vacuum system which removes dust and debris from the surface as it is blasted. The safety and health evaluation during the testing focused on two main areas of exposure: dust and noise.

NONE

1997-07-31

381

A computational model of blast loading on the human eye.  

PubMed

Ocular injuries from blast have increased in recent wars, but the injury mechanism associated with the primary blast wave is unknown. We employ a three-dimensional fluid-structure interaction computational model to understand the stresses and deformations incurred by the globe due to blast overpressure. Our numerical results demonstrate that the blast wave reflections off the facial features around the eye increase the pressure loading on and around the eye. The blast wave produces asymmetric loading on the eye, which causes globe distortion. The deformation response of the globe under blast loading was evaluated, and regions of high stresses and strains inside the globe were identified. Our numerical results show that the blast loading results in globe distortion and large deviatoric stresses in the sclera. These large deviatoric stresses may be indicator for the risk of interfacial failure between the tissues of the sclera and the orbit. PMID:23591604

Bhardwaj, Rajneesh; Ziegler, Kimberly; Seo, Jung Hee; Ramesh, K T; Nguyen, Thao D

2014-01-01

382

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

383

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

NASA Technical Reports Server (NTRS)

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.

1991-01-01

384

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

385

Open thoracotomy and pleural abrasion in the treatment of spontaneous pneumothorax in cystic fibrosis.  

PubMed

The various treatments of spontaneous pneumothorax in cystic fibrosis are examined over a 15-yr period. Open thoracotomy with pleural abrasion is compared to observation, tube thoracostomy, and tube thoracostomy with instillation of quinacrine. Open thoracotomy with pleural abrasion has been performed 31 times in 20 patients. Discussion centers around selection of patients, preoperative preparation, operative technique, and postoperative care and follow-up, including analysis of pulmonary function studies. In our experience, open thoracotomy with pleural abrasion is a safe and effective method that should be utilized in the management of pneumothorax in patients with cystic fibrosis. PMID:671188

Rich, R H; Warwick, W J; Leonard, A S

1978-06-01

386

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

387

Plasma-polymerized coating for polycarbonate: Single-layer, abrasion resistant, and antireflection  

NASA Technical Reports Server (NTRS)

Plasma-polymerized vinyl trimethoxy silane films were deposited on transparent polycarbonate substrates. The adherent, clear films protected the substrates from abrasion and also served as antireflection coatings. Post-treatment of the vinyl trimethoxy silane films in an oxygen glow discharge further improved their abrasion resistance. The coatings were characterized by elemental analysis of the bulk, ESCA analysis of the surface, transmission, thickness, abrasion resistance, haze, and adhesion. This patented process is currently used by the world's largest manufacturers of non-prescription sunglasses to protect the plastic glasses from scratching and thereby to increase their useful lifetime.

Wydeven, Theodore

1991-01-01

388

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

389

Modeling of aqueous foam blast wave attenuation  

NASA Astrophysics Data System (ADS)

The use of aqueous foams enables the mitigation of blast waves induced by the explosion of energetic materials. The two-phase confinement gives rise to interphase interactions between the gaseous and liquid phases, which role have been emphasized in shock-tube studies with solid foams [1, 2]. Multifluid formalism enables the thermo-mechanical disequilibria between phases to be taken into account. The flow model ensures the correct estimation of the acoustic impedance of the two-phase media. As for the numerical scheme, Riemann solvers are used to describe the microscopic fluid interactions, the summation of which provides the multiphase flux. The role of the different transfer mechanisms is evaluated in the case where the liquid ligaments of the foam matrix have been shattered into droplets by the shock impingement. Characteristics of blast waves in heterogeneous media leads to a decrease of overpressure. The numerical results have been compared favorably to experimental data [3, 4].

Del Prete, E.; Chinnayya, A.; Hadjadj, A.; Domergue, L.; Haas, J.-F.; Imbert, B.

390

A Phased Array Approach to Rock Blasting  

SciTech Connect

A series of laboratory-scale simultaneous two-hole shots was performed in a rock simulant (mortar) to record the shock wave interference patterns produced in the material. The purpose of the project as a whole was to evaluate the usefulness of phased array techniques of blast design, using new high-precision delay technology. Despite high-speed photography, however, we were unable to detect the passage of the shock waves through the samples to determine how well they matched the expected interaction geometry. The follow-up mine-scale tests were therefore not conducted. Nevertheless, pattern analysis of the vectors that would be formed by positive interference of the shockwaves from multiple charges in an ideal continuous, homogeneous, isotropic medium indicate the potential for powerful control of blast design, given precise characterization of the target rock mass.

Leslie Gertsch; Jason Baird

2006-07-01

391

Centrifugal shot blasting. Innovative technology summary report  

SciTech Connect

At the US Department of Energy (DOE) Fernald Environmental Management Project (FEMP), the Facilities Closure and Demolition Projects Integrated Remedial Design/Remedial Action (RD/RA) work plan calls for the removal of one inch (1 in) depth of concrete surface in areas where contamination with technetium-99 has been identified. This report describes a comparative demonstration between two concrete removal technologies: an innovative system using Centrifugal Shot Blasting (CSB) and a modified baseline technology called a rotary drum planer.

Not Available

1999-07-01

392

The Blast Energy Efficiency of GRBs  

E-print Network

Using data mostly assembled by previous authors, we consider the linear correlation between the apparent radiative efficiency $\\epsilon_{\\gamma}$ (defined as the ratio of isotropic equivalent radiative output to inferred isotropic equivalent kinetic energy of the blast) and $E_{peak}^{\\alpha}$ where $1.4efficiency is $\\sim 7$. We also find preliminary evidence (with a small sample) for a separate class of weak GRB afterglows.

David Eichler Daniel Jontof-Hutter

2005-03-24

393

Explosive parcel containment and blast mitigation container  

SciTech Connect

The present invention relates to a containment structure for containing and mitigating explosions. The containment structure is installed in the wall of the building and has interior and exterior doors for placing suspicious packages into the containment structure and retrieving them from the exterior of the building. The containment structure has a blast deflection chute and a blowout panel to direct over pressure from explosions away from the building, surrounding structures and people.

Sparks, Michael H. (Frederick County, MD)

2001-06-12

394

Experimental Testing of an Electrical Submersible Pump Undergoing Abrasive Slurry Erosion  

E-print Network

The Electrical Submersible Pump (ESP) manufactured by Baker Hughes, model no. WJE-1000 is designed for wells that are expected to have a high content of abrasive solids. It is a mixed flow, tandem compression type pump. Although the erosion...

Saleh, Ramy Moaness M

2013-04-01

395

Abrasive wear resistance of plasma-sprayed tungsten carbide–cobalt coatings  

Microsoft Academic Search

Plasma-sprayed coatings were produced by both air (APS) and low-pressure (VPS) methods from powders containing tungsten carbide with 9, 12 and 17wt% Co. Abrasive wear tests under conditions of low stress (with a rubber wheel) and high stress (steel wheel) were performed with 100–150-?m abrasive silica sand on the coatings as well as on low-carbon steel control samples at loads

H Chen; I. M Hutchings

1998-01-01

396

Abrasive wear behaviour of hard powders filled glass fabric–epoxy hybrid composites  

Microsoft Academic Search

The effect of incorporation of tungsten carbide (WC) and tantalum niobium carbide (Ta\\/NbC) powders on three-body abrasive wear behaviour in glass fabric–epoxy (G–E) composites was investigated and findings are analysed. A vacuum assisted resin transfer moulding (VARTM) technique was employed to obtain a series of G–E composites containing different fillers (WC and WC+Ta\\/NbC). Dry sand rubber wheel abrasion test was

N. Mohan; S. Natarajan; S. P. KumareshBabu

2011-01-01

397

Environmental influences on the abrasion resistance of a coil coating system  

Microsoft Academic Search

The protective properties of organic coatings against corrosion in coil coating systems, require good protection from abrasion and the chemical environment. In addition, mechanical damage and aggressive solutions can locally reduce the protective properties of paints.In this paper, a slurry made of abrasive sand and aqueous solution containing different ions at different pH or organic solvents was used.The evaluation of

S. Rossi; F. Deflorian; J. Fiorenza

2007-01-01

398

Plasma polymerized coating for polycarbonate - Single layer, abrasion resistant, and antireflection  

NASA Technical Reports Server (NTRS)

Plasma polymerized vinyltrimethoxy silane films were deposited on transparent polycarbonate substrates. The adherent, clear films protected the substrates from abrasion and also served as antireflection coatings. Posttreatment of the vinyltrimethoxy silane films in an oxygen glow discharge further improved the abrasion resistance. ESCA (electron spectroscopy for chemical analysis) and IR transmission spectra of some films were recorded, and an elemental analysis of the films was obtained.

Wydeven, T.

1977-01-01

399

A study of the abrasive wear behaviour of laser-clad tool steel coatings  

Microsoft Academic Search

A comparative study of the abrasive wear behaviour has been conducted on several tool steel coatings that were deposited by laser cladding process using a CW CO2 laser in combination with a blown powder feed technique. The laser-clad CPM 15V and CPM 10V coatings exhibit superior abrasive wear resistance as compared with the reference material, AISI D2 tool steel. In

S.-H. Wang; J.-Y. Chen; L. Xue

2006-01-01

400

Preliminary Results from the 1999 Balloon Flight of the Liquid Xenon Gamma-Ray Imaging Telescope (LXeGRIT)  

E-print Network

LXeGRIT is a balloon-borne Compton telescope employing a large volume liquid xenon time projection chamber (LXeTPC) as the central gamma-ray detector. It is designed to image gamma rays in the energy range of 200 keV to 20 MeV, with an angular resolution of about 3 degrees (1 sigma) at 2 MeV, within a field-of-view (FOV) of about 1 sr. The detector's energy and three-dimensional spatial resolution as measured during pre-flight calibration experiments, are $\\Delta E_\\mathrm{lxe}/E=8.8% : \\sqrt{1\\MeV /E}$ and < 1mm RMS, respectively. The detection efficiency for Compton events varies between 1.5% and 4% depending on energy and event selection. We describe the instrument as flown on May 7, 1999 and review its overall performance at balloon altitude. The launch occurred at 13:26:54 UT from Ft. Sumner, New Mexico and the flight was terminated about 9 hours later. The Crab was in the instrument FOV for a few hours. Analysis of these data is in progress.

Aprile, E; Curioni, A; Egorov, V; Giboni, K L; Ventura, Sandro; Doke, T; Kikuchi, J; Takizawa, K; Chupp, E L; Dunphy, P P

2000-01-01

401

Performance of the Light Trigger System in the Liquid Xenon Gamma-Ray Telescope LXeGRIT  

E-print Network

LXeGRIT is a balloon-borne Compton telescope for MeV gamma-ray astrophysics, based on a liquid xenon time projection chamber with charge and light readout. The energy and direction of an incident gamma-ray is reconstructed from the three-dimensional locations and energy deposits of individual interactions taking place in the homogeneous detector volume. While the charge signals provide energy information and X-Y positions, the fast xenon scintillation light signal is used to trigger the detector. The drift time measurement, referred to the time of the trigger signal, gives the Z-position with the known drift velocity. The light is detected by four UV-sensitive photomultiplier tubes (PMTs). The logical OR of the PMT signals triggers the data acquisition system with an efficiency which depends on the event energy and location, as well as on the discriminator thresholds used on the individual PMTs. Results from experiments with a tagged 22Na source give the spatial distribution of the light trigger efficiency fo...

Oberlack, U G; Curioni, A; Giboni, K

2000-01-01

402

An Upgraded Data Acquisition System for the Balloon-Borne Liquid Xenon Gamma-Ray Telescope LXeGRIT  

E-print Network

LXeGRIT is a balloon-borne Compton telescope for MeV gamma-ray astrophysics, based on a liquid xenon time projection chamber (LXe-TPC) with charge and light readout. The first balloon flights in 1997 revealed limitations of the trigger electronics and the data acquisition (DAQ) system, leading to their upgrade. New electronics was developed to handle the xenon scintillation light trigger. The original processor module was replaced by a commercial VME processor. The telemetry rate was doubled to 2 x 500 kbps and onboard data storage on hard disks was implemented. Relying on a robust real-time operating system, the new DAQ software adopts an object oriented design to implement the diverse tasks of trigger handling, data selection, transmission, and storage, as well as DAQ control and monitor functions. The new systems performed well during two flights in Spring 1999 and Fall 2000. In the 2000 flight, the DAQ system was able to handle 300-350 triggers/s out of a total of about 650 Hz, including charged particles.

E. Aprile; A. Curioni; K. Giboni; U. Oberlack; ; S. Ventura

2000-12-12

403

The Effect of Carbon Dioxide (CO2) Laser on Sandblasting with Large Grit and Acid Etching (SLA) Surface  

PubMed Central

Introduction: The purpose of this study was to investigate the effect of 6W power Carbon Dioxide Laser (CO2) on the biologic compatibility of the Sandblasting with large grit and acid etching (SLA) titanium discs through studying of the Sarcoma Osteogenic (SaOS-2) human osteoblast-like cells viability. Methods: Sterilized titanium discs were used together with SaOS-2 human osteoblast-like cells. 6 sterilized SLA titanium discs of the experimental group were exposed to irradiation by CO2 laser with a power of 6W and 10.600nm wavelength, at fixed frequency of 80Hz during 45 seconds in both pulse and non-contact settings. SaOS-2 human osteoblast-like cells were incubated under 37°C in humid atmosphere (95% weather, 5% CO2) for 72 hours. MTT test was performed to measure the ratio level of cellular proliferation. Results: The results indicated that at 570nm wavelength, the 6W CO2 laser power have not affected the cellular viability. Conclusion: CO2 laser in 6w power has had no effect on the biologic compatibility of the SLA titanium surface

Foroutan, Tahereh; Ayoubian, Nader

2013-01-01

404

Minimization of carryover for high-throughput liquid chromatography with tandem mass spectrometry analysis of 14 mycotoxins in corn grits.  

PubMed

A method for the simultaneous analysis of 14 mycotoxins with the minimization of carryover was developed. Our verification experiments suggested that the carryover occurred due to the chelation of fumonisins with the metal. To wash the fumonisins from the metal, the inner surface of the injection needle was rinsed with 10 mM trisodium citrate and 1% formic acid in water/methanol/acetonitrile/isopropanol after each injection, and the analysis was performed on a metal-free Mastro C18 column. This approach remarkably minimized the carryover of fumonisins. Fourteen mycotoxins in samples were extracted with 2% acetic acid in water/acetonitrile and a quick, easy, cheap, effective, rugged, and safe extraction kit, purified on a MultiSep 229 Ochra, and then quantified by liquid chromatography with tandem mass spectrometry. Determinations performed using this method produced a linearity greater than 0.99 and recoveries ranging from 72.6 to 117.4%, with good intraday precision from 4.0 to 12.4%, and interday precision from 6.5 to 17.0%. The limits of detection ranged from 0.01 to 0.71 ?g/kg, demonstrating that a highly sensitive method for the simultaneous analysis of mycotoxins over a wide range of concentrations was achieved with minimal carryover. When 12 samples of commercially available corn grits were analyzed with this method, deoxynivalenol, fumonisin B1, fumonisin B2, fumonisin B3, and zearalenone were present most frequently. PMID:24723378

Tamura, Masayoshi; Matsumoto, Keiko; Watanabe, Jun; Iida, Junko; Nagatomi, Yasushi; Mochizuki, Naoki

2014-07-01

405

A study of the sensitivity of an imaging telescope (GRITS) for high energy gamma-ray astronomy  

NASA Technical Reports Server (NTRS)

When a gamma-ray telescope is placed in Earth orbit, it is bombarded by a flux of cosmic protons much greater than the flux of interesting gammas. These protons can interact in the telescope's thermal shielding to produce detectable gamma rays, most of which are vetoed. Since the proton flux is so high, the unvetoed gamma rays constitute a significant background relative to some weak sources. This background increases the observing time required to pinpoint some sources and entirely obscures other sources. Although recent telescopes have been designed to minimize this background, its strength and spectral characteristics were not previously calculated in detail. Monte Carlo calculations are presented which characterize the strength, spectrum and other features of the cosmic proton background using FLUKA, a hadronic cascade program. Several gamma-ray telescopes, including SAS-2, EGRET and the Gamma Ray Imaging Telescope System (GRITS), are analyzed, and their proton-induced backgrounds are characterized. In all cases, the backgrounds are either shown to be low relative to interesting signals or suggestions are made which would reduce the background sufficiently to leave the telescope unimpaired. In addition, several limiting cases are examined for comparison to previous estimates and calibration measurements.

Yearian, Mason R.

1990-01-01

406

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

407

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

408

Durability of traditional plasters with respect to blast furnace slag-based plaster  

SciTech Connect

Blast furnace slag is a residue of steel production. It is a latent hydraulic binder and is normally used to improve the durability of concrete and mortars. Slag could be also used as rendering mortar for masonry and old buildings. Today, cement and hydraulic lime are the most popular hydraulic binders used to make plasters. They are characterised by a low durability when exposed to the action of chemical and physical agents. The aim of this study was to provide a comparison between the physical-mechanical properties of some renders made with ordinary Portland cement, hydraulic lime, or slag. Furthermore, an investigation was carried out to analyse mortar resistance to several aggressive conditions like acid attack, freezing and thawing cycles, abrasion, sulphate aggression, cycles in ultraviolet screening device, and salt diffusion. The specimens, after chemical attack, have been characterised from the chemical-physical [specific surface according to the BET (Brunauer-Emmet-Teller) method], crystal-chemical (X-ray diffraction, XRD), and morphological (scanning electron microscopy, SEM) points of view.

Cerulli, T.; Pistolesi, C.; Maltese, C.; Salvioni, D

2003-09-01

409

Experimental Study on Abrasive Waterjet Polishing of Hydraulic Turbine Blades  

NASA Astrophysics Data System (ADS)

In this paper, an experimental investigation is implemented on the abrasive waterjet polishing technique to evaluate its capability in polishing of surfaces and edges of hydraulic turbine blades. For this, the properties of this method are studied and the main parameters affecting its performance are determined. Then, an experimental test-rig is designed, manufactured and tested to be used in this study. This test-rig can be used to polish linear and planar areas on the surface of the desired workpieces. Considering the number of parameters and their levels, the Taguchi method is used to design the preliminary experiments. All experiments are then implemented according to the Taguchi L18 orthogonal array. The signal-to-noise ratios obtained from the results of these experiments are used to determine the importance of the controlled polishing parameters on the final quality of the polished surface. The evaluations on these ratios reveal that the nozzle angle and the nozzle diameter have the most important impact on the results. The outcomes of these experiments can be used as a basis to design a more precise set of experiments in which the optimal values of each parameter can be estimated.

Khakpour, H.; Birglenl, L.; Tahan, A.; Paquet, F.

2014-12-01

410

Abrasive wear of intermetallic-based alloys and composites  

SciTech Connect

In this study, the abrasive wear behavior of Fe3Al, TiAl, Ti3Al, Al3Ti, NiAl, Ni3Al and MoSi2, and composites based on these compounds, were assessed and compared to the behavior of selected metals, alloys and ceramics. Under the wear conditions used for these tests, the softer intermetallic compounds (e.g. TiAl and Fe3Al) behaved in a manner similar to the metals and alloys, whereas, the harder intermetallic compound (i.e. MoSi2) behaved more like a ceramic. The influence of Al atomic fraction, superlattice structure and ternary alloying additions on the wear behavior of Fe3Al was investigated. Controlling the Al content and third element additions affected wear resistance more than superlattice structure. Composite strengthening was also explored as a method for improving wear resistance. The addition of hard second phase particles (i.e. TiB2 to NiAl and SiC to MoSi2) was also very effective improving wear resistance. Surprisingly, the addition of softer Nb particles did not significantly degrade the wear resistance of a MoSi2 matrix, even at Nb additions of 40%.

Hawk, Jeffrey A.; Alman, David E.

1997-12-01

411

Ultimate in building energy analysis: DOE2 and BLAST  

Microsoft Academic Search

The DOE-2 and BLAST computer programs are investigated in terms of their usefulness in building energy analysis. DOE-2 and BLAST are generally classed as high-level, computer-dynamic methods that are based on hour-by-hour computation. The characteristics of DOE-2 and BLAST are discussed with emphasis on their solar simulation features, and their capabilities are contrasted and related. Typical applications of the programs

B. D. Hunn

1981-01-01

412

Mechanisms and Treatment of Blast Induced Hearing Loss  

PubMed Central

The main objective of this study is to provide an overview of the basic mechanisms of blast induced hearing loss and review pharmacological treatments or interventions that can reduce or inhibit blast induced hearing loss. The mechanisms of blast induced hearing loss have been studied in experimental animal models mimicking features of damage or injury seen in human. Blast induced hearing loss is characterized by perforation and rupture of the tympanic membrane, ossicular damage, basilar membrane damage, inner and outer hair cell loss, rupture of round window, changes in chemical components of cochlear fluid, vasospasm, ischemia, oxidative stress, excitotoxicity, hematoma, and hemorrhage in both animals and humans. These histopathological consequences of blast exposure can induce hearing loss, tinnitus, dizziness, and headache. The pharmacological approaches to block or inhibit some of the auditory pathological consequences caused by blast exposure have been developed with antioxidant drugs such as 2,4-disulfonyl ?-phenyl tertiary butyl nitrone (HXY-059, now called HPN-07) and N-acetylcysteine (NAC). A combination of antioxidant drugs (HPN-07 and NAC) was administered to reduce blast induced cochlear damage and hearing loss. The combination of the antioxidant drugs can prevent or treat blast induced hearing loss by reducing damage to the mechanical and neural component of the auditory system. Although information of the underlying mechanisms and treatment of blast induced hearing loss are provided, further and deep research should be achieved due to the limited and controversial knowledge. PMID:24653882

2012-01-01

413

13. BUILDING NO. 621, INTERIOR, TOP OF BLASTING TUB UNDERNEATH ...  

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

13. BUILDING NO. 621, INTERIOR, TOP OF BLASTING TUB UNDERNEATH SAWDUST HOPPER. BLASTING TUB HAS DOUBLE WALLS OF 3/4' THICK STEEL ARMOR PLATE. CHARGE TO BE TESTED IS BURIED IN SAWDUST WITH FLAME RESISTANT CHEMICALS. ELEVATOR BEHIND TUB CARRIES SAWDUST BACK TO TOP OF SAWDUST HOPPER AFTER TEST IS COMPLETED AND SAWDUST IN BLASTING TUB HAS BEEN SIFTED FOR SHELL FRAGMENTS. LOUVERS IN WALLS ARE HINGED FREELY SO THEY OPEN TO RELIEVE BLAST PRESSURE DURING A TEST. - Picatinny Arsenal, 600 Area, Test Areas District, State Route 15 near I-80, Dover, Morris County, NJ

414

On the Interaction and Coalescence if Spherical Blast Waves  

NASA Technical Reports Server (NTRS)

The scaling and similarity laws concerning the propagation of isolated spherical blast waves are briefly reviewed. Both point source explosions and high pressure gas explosions are considered. Test data on blast overpressure from the interaction and coalescence of spherical blast waves emanating from explosives in the form of shaped charges of different strength 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. The results point out the possibility of detecting source explosions from far-field pressure measurements.

Kandula, Max; Freeman, Robert J.

2005-01-01

415

Mechanisms of hearing loss after blast injury to the ear.  

PubMed

Given the frequent use of improvised explosive devices (IEDs) around the world, the study of traumatic blast injuries is of increasing interest. The ear is the most common organ affected by blast injury because it is the body's most sensitive pressure transducer. We fabricated a blast chamber to re-create blast profiles similar to that of IEDs and used it to develop a reproducible mouse model to study blast-induced hearing loss. The tympanic membrane was perforated in all mice after blast exposure and found to heal spontaneously. Micro-computed tomography demonstrated no evidence for middle ear or otic capsule injuries; however, the healed tympanic membrane was thickened. Auditory brainstem response and distortion product otoacoustic emission threshold shifts were found to be correlated with blast intensity. As well, these threshold shifts were larger than those found in control mice that underwent surgical perforation of their tympanic membranes, indicating cochlear trauma. Histological studies one week and three months after the blast demonstrated no disruption or damage to the intra-cochlear membranes. However, there was loss of outer hair cells (OHCs) within the basal turn of the cochlea and decreased spiral ganglion neurons (SGNs) and afferent nerve synapses. Using our mouse model that recapitulates human IED exposure, our results identify that the mechanisms underlying blast-induced hearing loss does not include gross membranous rupture as is commonly believed. Instead, there is both OHC and SGN loss that produce auditory dysfunction. PMID:23840874

Cho, Sung-Il; Gao, Simon S; Xia, Anping; Wang, Rosalie; Salles, Felipe T; Raphael, Patrick D; Abaya, Homer; Wachtel, Jacqueline; Baek, Jongmin; Jacobs, David; Rasband, Matthew N; Oghalai, John S

2013-01-01

416

Abrasive wear behavior of D2 tool steel with respect to load and sliding speed under dry sand\\/rubber wheel abrasion condition  

Microsoft Academic Search

The dry sand\\/rubber wheel abrasion tester is widely used in industry and laboratories to evaluate wear and rank materials. For industrial application, this apparatus is often used under a fixed load and a fixed speed to have all tested materials evaluated under the same condition. However, whether or not such a test with fixed load and speed can provide accurate

X. Ma; R. Liu; D. Y. Li

2000-01-01

417

1997 Oxford University Press 33893402Nucleic Acids Research, 1997, Vol. 25, No. 17 Gapped BLAST and PSI-BLAST: a new generation of  

E-print Network

and PSI-BLAST: a new generation of protein database search programs Stephen F. Altschul*, Thomas L. Madden-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

Batzoglou, Serafim

418

29 CFR 1926.905 - Loading of explosives or blasting agents.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Loading of explosives or blasting agents. 1926.905 Section...FOR CONSTRUCTION Blasting and the Use of Explosives § 1926.905 Loading of explosives or blasting agents. (a)...

2010-07-01

419

77 FR 31878 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Blasting...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Request; Blasting Operations and Use of Explosives Standard ACTION: Notice...Blasting Operations and Use of Explosives Standard,'' to the Office of Management...INFORMATION: The Blasting and Use of Explosives Standard at 29 CFR part 1926,...

2012-05-30

420

29 CFR 1926.904 - Storage of explosives and blasting agents.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Storage of explosives and blasting agents. 1926.904 Section...FOR CONSTRUCTION Blasting and the Use of Explosives § 1926.904 Storage of explosives and blasting agents. (a)...

2012-07-01

421

29 CFR 1926.904 - Storage of explosives and blasting agents.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Storage of explosives and blasting agents. 1926.904 Section...FOR CONSTRUCTION Blasting and the Use of Explosives § 1926.904 Storage of explosives and blasting agents. (a)...

2010-07-01

422

29 CFR 1926.904 - Storage of explosives and blasting agents.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Storage of explosives and blasting agents. 1926.904 Section...FOR CONSTRUCTION Blasting and the Use of Explosives § 1926.904 Storage of explosives and blasting agents. (a)...

2013-07-01

423

29 CFR 1926.904 - Storage of explosives and blasting agents.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Storage of explosives and blasting agents. 1926.904 Section...FOR CONSTRUCTION Blasting and the Use of Explosives § 1926.904 Storage of explosives and blasting agents. (a)...

2014-07-01

424

30 CFR 817.68 - Use of explosives: Records of blasting operations.  

Code of Federal Regulations, 2013 CFR

...Location, date, and time of the blast. (c) Name, signature...the blaster conducting the blast. (d) Identification...in feet, from the nearest blast hole to the nearest dwelling, public building, school, church,...

2013-07-01

425

30 CFR 817.68 - Use of explosives: Records of blasting operations.  

Code of Federal Regulations, 2011 CFR

...Location, date, and time of the blast. (c) Name, signature...the blaster conducting the blast. (d) Identification...in feet, from the nearest blast hole to the nearest dwelling, public building, school, church,...

2011-07-01

426

30 CFR 816.68 - Use of explosives: Records of blasting operations.  

Code of Federal Regulations, 2010 CFR

...Location, date, and time of the blast. (c) Name, signature...the blaster conducting the blast. (d) Identification...in feet, from the nearest blast hole to the nearest dwelling, public building, school, church,...

2010-07-01

427

30 CFR 816.68 - Use of explosives: Records of blasting operations.  

Code of Federal Regulations, 2013 CFR

...Location, date, and time of the blast. (c) Name, signature...the blaster conducting the blast. (d) Identification...in feet, from the nearest blast hole to the nearest dwelling, public building, school, church,...

2013-07-01

428

30 CFR 817.68 - Use of explosives: Records of blasting operations.  

Code of Federal Regulations, 2010 CFR

...Location, date, and time of the blast. (c) Name, signature...the blaster conducting the blast. (d) Identification...in feet, from the nearest blast hole to the nearest dwelling, public building, school, church,...

2010-07-01

429

30 CFR 816.68 - Use of explosives: Records of blasting operations.  

Code of Federal Regulations, 2012 CFR

...Location, date, and time of the blast. (c) Name, signature...the blaster conducting the blast. (d) Identification...in feet, from the nearest blast hole to the nearest dwelling, public building, school, church,...

2012-07-01

430

30 CFR 816.68 - Use of explosives: Records of blasting operations.  

Code of Federal Regulations, 2014 CFR

...Location, date, and time of the blast. (c) Name, signature...the blaster conducting the blast. (d) Identification...in feet, from the nearest blast hole to the nearest dwelling, public building, school, church,...

2014-07-01

431

30 CFR 816.68 - Use of explosives: Records of blasting operations.  

Code of Federal Regulations, 2011 CFR

...Location, date, and time of the blast. (c) Name, signature...the blaster conducting the blast. (d) Identification...in feet, from the nearest blast hole to the nearest dwelling, public building, school, church,...

2011-07-01

432

30 CFR 817.68 - Use of explosives: Records of blasting operations.  

Code of Federal Regulations, 2014 CFR

...Location, date, and time of the blast. (c) Name, signature...the blaster conducting the blast. (d) Identification...in feet, from the nearest blast hole to the nearest dwelling, public building, school, church,...

2014-07-01

433

30 CFR 817.68 - Use of explosives: Records of blasting operations.  

Code of Federal Regulations, 2012 CFR

...Location, date, and time of the blast. (c) Name, signature...the blaster conducting the blast. (d) Identification...in feet, from the nearest blast hole to the nearest dwelling, public building, school, church,...

2012-07-01

434

Biologic response to complex blast waves  

SciTech Connect

Small, bare charges were detonated inside an M59 armored personnel carrier (APC) in an attempt to simulate the complex blast waves generated by the jets from shaped-charge warheads penetrating into armored vehicles. Anesthetized sheep were placed inside the APC at 92- and 122-cm ranges from 57- or 113-g pentolite charges. Pressure-time was measured by pressure transducers either mounted on the animals or free standing at comparable ranges on the opposite side of the vehicle. In general, the waveforms were characterized by an initial shock wave of less than 1-msec duration followed by repeated reflections of decreasing magnitude. No deaths nor lung hemorrhages were observed, but all the animals sustained severe ear injury. Animals subjected to peak overpressures of 1.2 to 2.3 bar from the 113-g explosions also received slight non-auditory blast injuries to the upper respiratory and gastrointestinal tracts; those exposed to peak overpressures of just under 1 bar from the 57-g charges did not. The non-auditory blast injuries inside the APC were more severe than those sustained by sheep at comparable distances from 113-g charges in the open. The results suggested that the biological consequences of a complex wave of the type encountered in this study can be equated approximately to a Friedlander wave with a peak overpressure equal to that of the complex wave and with a total impulse equal to the impulse over the first 2 to 3 msec of the complex wave. 9 refs., 7 figs., 1 tab.

Richmond, D.R.; Yelverton, J.T.; Fletcher, E.R.; Phillips, Y.Y.

1985-01-01

435

BLAST: RESOLVING THE COSMIC SUBMILLIMETER BACKGROUND  

SciTech Connect

The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) has made 1 deg{sup 2}, deep, confusion-limited maps at three different bands, centered on the Great Observatories Origins Deep Survey South Field. By calculating the covariance of these maps with catalogs of 24 mum sources from the Far-Infrared Deep Extragalactic Legacy Survey, we have determined that the total submillimeter intensities are 8.60 +- 0.59, 4.93 +- 0.34, and 2.27 +- 0.20 nW m{sup -2} sr{sup -1} at 250, 350, and 500 mum, respectively. These numbers are more precise than previous estimates of the cosmic infrared background (CIB) and are consistent with 24 mum-selected galaxies generating the full intensity of the CIB. We find that the fraction of the CIB that originates from sources at z >= 1.2 increases with wavelength, with 60% from high-redshift sources at 500 mum. At all BLAST wavelengths, the relative intensity of high-z sources is higher for 24 mum-faint sources than that for 24 mum-bright sources. Galaxies identified as active galactic nuclei (AGNs) by their Infrared Array Camera colors are 1.6-2.6 times brighter than the average population at 250-500 mum, consistent with what is found for X-ray-selected AGNs. BzK-selected galaxies are found to be moderately brighter than typical 24 mum-selected galaxies in the BLAST bands. These data provide high-precision constraints for models of the evolution of the number density and intensity of star-forming galaxies at high redshift.

Marsden, Gaelen; Chapin, Edward L.; Halpern, Mark; Ngo, Henry [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1 (Canada); Ade, Peter A. R.; Griffin, Matthew; Hargrave, Peter C.; Mauskopf, Philip; Moncelsi, Lorenzo; Pascale, Enzo [School of Physics and Astronomy, Cardiff University, 5 The Parade, Cardiff, CF24 3AA (United Kingdom); Bock, James J. [Jet Propulsion Laboratory, Pasadena, CA 91109-8099 (United States); Devlin, Mark J.; Dicker, Simon R.; Klein, Jeff [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Gundersen, Joshua O. [Department of Physics, University of Miami, 1320 Campo Sano Drive, Coral Gables, FL 33146 (United States); Hughes, David H. [Instituto Nacional de AstrofIsica Optica y Electronica (INAOE), Aptdo. Postal 51 y 72000 Puebla (Mexico); Magnelli, Benjamin [Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/Service d'Astrophysique, Bat. 709, CEA-Saclay, F-91191 gif-sur-Yvette Cedex (France); Netterfield, Calvin B. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Olmi, Luca [Physics Department, University of Puerto Rico, Rio Piedras Campus, Box 23343, UPR station, Puerto Rico 00931 (United States); Patanchon, Guillaume, E-mail: gmarsden@phas.ubc.c [Universite Paris Diderot, Laboratoire APC, 10, rue Alice Domon et Leonie Duquet 75205 Paris (France)

2009-12-20

436

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

437

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

438

Air blast loading of a cylindrical body  

NASA Astrophysics Data System (ADS)

Pressure measurements were performed on the surface of a cylinder in shock tube experiments and in free field tests. In shock tube measurements, pressure waves with a rather sharp profile were observed, with overpressures ranging from 0.2 to 2 bar. Unsteady gain coefficients were obtained for weak and moderately strong incident shocks. In free field tests, blast waves at the point of contact with the body produced a reflected pressure of 4.3 bar, corresponding to an overpressure of 1.4 bar or a shock Mach number of 1.5. The results are presented in graphical form.

Heilig, W.

439

NASA TEERM Project: Corn Based Blast Media  

NASA Technical Reports Server (NTRS)

Coatings removal is a necessary part of the maintenance, repair, and overhaul activities at many NASA centers and contractor support sites. Sensitive substrates, such as composites and thin aluminum alloys require special handling such as the use of chemical stripping, pneumatic hand sanding, or softer blast media. Type V, acrylic based PMB is commonly used to de-coat, strip, or de-paint the delicate substrates of the Solid Rocket Boosters (SRBs) currently used in support of the Shuttle and slated to be used in support of CxP.

Griffin, Chuck

2009-01-01

440

Identification of major blast resistance genes in the southern US  

Technology Transfer Automated Retrieval System (TEKTRAN)

Resistance (R) genes in rice play important roles in preventing infections of rice blast fungus, Magnaporthe oryzae. In order to identify more R genes for different rice growing areas in the Southern US, an extensive field survey of the blast fungus was performed from 2012 to 2013. A total of 500 is...

441

Blast Loading Experiments of Surrogate Models for Tbi Scenarios  

NASA Astrophysics Data System (ADS)

This study aims to characterize the interaction of explosive blast waves through simulated anatomical models. We have developed physical models and a systematic approach for testing traumatic brain injury (TBI) mechanisms and occurrences. A simplified series of models consisting of spherical PMMA shells housing synthetic gelatins as brain simulants have been utilized. A series of experiments was conducted to compare the sensitivity of the system response to mechanical properties of the simulants under high strain-rate explosive blasts. Small explosive charges were directed at the models to produce a realistic blast wave in a scaled laboratory test cell setting. Blast profiles were measured and analyzed to compare system response severity. High-speed shadowgraph imaging captured blast wave interaction with the head model while particle tracking captured internal response for displacement and strain correlation. The results suggest amplification of shock waves inside the head near material interfaces due to impedance mismatches. In addition, significant relative displacement was observed between the interacting materials suggesting large strain values of nearly 5%. Further quantitative results were obtained through shadowgraph imaging of the blasts confirming a separation of time scales between blast interaction and bulk movement. These results lead to the conclusion that primary blast effects could cause TBI occurrences.

Alley, M. D.; Son, S. F.

2009-12-01

442

Current advances on genetic resistance to rice blast disease  

Technology Transfer Automated Retrieval System (TEKTRAN)

Rice blast disease caused by the fungal pathogen Magnaporthe oryzae is one of the most threatening fungal diseases resulting in significant annual crop losses worldwide. Blast disease has been effectively managed by a combination of resistant (R) gene deployment, application of fungicides, and suita...

443

EXTERIOR VIEW, NO. 3 CAST HOUSE CENTER AND BLAST FURNACE ...  

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

EXTERIOR VIEW, NO. 3 CAST HOUSE CENTER AND BLAST FURNACE NO. 3 (JANE FURNACE)/ORE BRIDGE TO THE RIGHT, WITH SINTERING PLANT CONVEYORS & TRANSFER HOUSE IN FOREGROUND. - Pittsburgh Steel Company, Monessen Works, Blast Furnace No. 3, Donner Avenue, Monessen, Westmoreland County, PA

444

5. SOUTHERN VIEW OF BLAST FURNACES No. 3, No. 4, ...  

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

5. SOUTHERN VIEW OF BLAST FURNACES No. 3, No. 4, AND No. 6, WITH ORE YARD IN THE FOREGROUND. BUILDING ON THE LEFT IS THE CENTRAL BOILER HOUSE. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

445

General view of blast furnace "A"; looking southeast; The building ...  

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

General view of blast furnace "A"; looking southeast; The building to the right is the crucible steel building - Bethlehem Steel Corporation, South Bethlehem Works, Blast Furnace "A", Along Lehigh River, North of Fourth Street, West of Minsi Trail Bridge, Bethlehem, Northampton County, PA

446

Performance of Runtime Optimization on BLAST Technical Report  

E-print Network

Performance of Runtime Optimization on BLAST Technical Report Department of Computer Science and Engineering University of Minnesota 4-192 EECS Building 200 Union Street SE Minneapolis, MN 55455-0159 USA TR 04-038 Performance of Runtime Optimization on BLAST Abhinav Das, Jiwei Lu, Howard Chen, Jinpyo Kim

Minnesota, University of

447

Building comfort analysis using BLAST: A case study. Final report  

Microsoft Academic Search

Energy analysis programs have traditionally modeled energy consumption of new or existing facilities. A new feature of the Building Loads Analysis and Systems Thermodynamics (BLAST) computer program includes the ability to model comfort parameters in addition to evaluating building energy performance. This study demonstrates this unique BLAST feature by examining the comfort parameters at a new Air Force Housing (UEPH)

R. J. Nemeth; L. K. Lwrie

1991-01-01

448

BLUNT TRAUMA FROM BLAST-INDUCED BUILDING DEBRIS  

Microsoft Academic Search

Protecting building occupants from blast effects is a primary focus of current research. One of the primary injury mechanisms is blunt trauma, as structural and architectural elements of the building as well as building contents are projected by the force of the blast and impact humans inside the building. A series of experiments was performed recently in which instrumented anthropomorphic

David Bogosian; Hrire Der Avanessian

449

Using computational fluid dynamics (CFD) for blast wave predictions  

Microsoft Academic Search

Explosions will, in most cases, generate blast waves. While simple models (e.g., Multi Energy Method) are useful for simple explosion geometries, most practical explosions are far from trivial and require detailed analyses. For a reliable estimate of the blast from a gas explosion it is necessary to know the explosion strength. The source explosion may not be symmetric; the pressure

Olav R. Hansen; Peter Hinze; Derek Engel; Scott Davis

2010-01-01

450

7. Air Blast Circuit Breaker Compressors, view to the southeast. ...  

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

7. Air Blast Circuit Breaker Compressors, view to the southeast. The air blast circuit breakers are visible in the left background of the photograph. - Washington Water Power Clark Fork River Noxon Rapids Hydroelectric Development, Powerhouse, South bank of Clark Fork River at Noxon Rapids, Noxon, Sanders County, MT

451

VIEW OF THE #2 BLAST FURNACE FROM THE EAST, SHOWING ...  

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

VIEW OF THE #2 BLAST FURNACE FROM THE EAST, SHOWING SKIP HOIST, DUST CATCHER AND STOCK BINS IN THE FOREGROUND. #2 CASTING SHED IS TO THE LEFT, HOT BLAST MAIN IS ON THE RIGHT. - Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham, Jefferson County, AL

452

Blast-furnace performance with coal-dust injection  

SciTech Connect

For the blast furnace shop at OAO Alchevskii Metallurgicheskii Kombinat (AMK) the injection of pulverized fuel is promising. Preliminary steps toward its introduction are underway, including analytical research. In this context, blast furnace performance when using pulverized coal is calculated in this study.

G.G. Vasyura [OAO Alchevskii Metallurgicheskii Kombinat, Alchevsk (Russian Federation)

2007-07-01

453

Computational studies of polyurea coated steel plate under blast loads  

E-print Network

structural dynamics analysis #12;Blast simulation · PUMA2, a computational fluid dynamics computer code. Validation of PUMA2 - Over-Pressure #12;Pressure Loading at the Center of the Plate · Results obtained using-Blast 2.2, Applied Research Associates, Inc.] #12;Comparison between PUMA2 and TM5- 1300 · TM5

454

Emission factors and source apportionment for abrasion particles produced by road traffic  

NASA Astrophysics Data System (ADS)

Particle emissions of road traffic are generally associated with fresh exhaust emissions only. However, recent studies identified a clear contribution of non-exhaust emissions to the PM10 load of the ambient air. These emissions consist of particles produced by abrasion from brakes, road wear, tire wear, as well as resuspension of deposited road dust. For many urban environments, quantitative information about the contributions of the individual abrasion processes is still scarce. For effective PM10 reduction scenarios it is of particular interest to know whether road wear, resuspension or fresh abrasion from vehicles is dominating the non-exhaust PM10 contribution. In Switzerland, the emissions of road traffic abrasion particles into the ambient air were characterized in the project APART (Abrasion Particles produced by Road Traffic). The project aimed at finding the contribution of the non-exhaust sources to total traffic-related PM10 and PM2.5 for different traffic conditions, by determining specific elemental fingerprint signatures for the various sources. This was achieved by hourly elemental mass concentration measurements in three size classes (2.5-10, 1-2.5 and 0.1-1 micrometers) with a rotating drum impactor (RDI) and subsequent synchrotron radiation X-ray fluorescence spectrometry (SR-XRF). The elemental fingerprint measurements were embedded into a large set of aerosol, gas phase, meteorological and traffic count measurements. To identify traffic related emissions, measurements were performed upwind and downwind of selected roads. For a better investigation of road wear, a road wear simulator was applied in additional experiments. This allows for the identification and quantification of the different source contributions by means of source-receptor modeling, and for the calculation of real-world emission factors for the individual abrasion sources. The preliminary analysis of hourly resolved trace element measurements in a street canyon in Zürich showed that Fe, Cu, Mo, Sn, Sb and Ba were clearly correlated with hourly traffic counts and were attributable to brake abrasion. It was estimated that more than 80% of the emissions of these elements originated from fresh brake abrasion rather than from resuspended PM10 road dust. The contribution of brake abrasion to the total traffic related PM10 emission in the street canyon was found to be approx. 15%. Furthermore, the road wear simulator experiments showed that resuspension of deposited road dust was dominating fresh road wear. The diurnal variation of the resuspended particles is not directly correlated to traffic counts but is rather driven by the local air mass circulation.

Bukowiecki, N.; Lienemann, P.; Figi, R.; Hill, M.; Richard, A.; Furger, M.; Rickers, K.; Cliff, S. S.; Baltensperger, U.; Gehrig, R.

2009-04-01

455

Computation of viscous blast wave flowfields  

NASA Technical Reports Server (NTRS)

A method to determine unsteady solutions of the Navier-Stokes equations was developed and applied. The structural finite-volume, approximately factored implicit scheme uses Newton subiterations to obtain the spatially and temporally second-order accurate time history of the interaction of blast-waves with stationary targets. The inviscid flux is evaluated using MacCormack's modified Steger-Warming flux or Roe flux difference splittings with total variation diminishing limiters, while the viscous flux is computed using central differences. The use of implicit boundary conditions in conjunction with a telescoping in time and space method permitted solutions to this strongly unsteady class of problems. Comparisons of numerical, analytical, and experimental results were made in two and three dimensions. These comparisons revealed accurate wave speed resolution with nonoscillatory discontinuity capturing. The purpose of this effort was to address the three-dimensional, viscous blast-wave problem. Test cases were undertaken to reveal these methods' weaknesses in three regimes: (1) viscous-dominated flow; (2) complex unsteady flow; and (3) three-dimensional flow. Comparisons of these computations to analytic and experimental results provided initial validation of the resultant code. Addition details on the numerical method and on the validation can be found in the appendix. Presently, the code is capable of single zone computations with selection of any permutation of solid wall or flow-through boundaries.

Atwood, Christopher A.

1991-01-01

456

Mercury in dumped blast furnace sludge.  

PubMed

Blast furnace sludge (BFS) is a waste generated in the production of pig iron and was dumped in sedimentation ponds. Sixty-five samples from seven BFS locations in Europe were investigated regarding the toxic element mercury (Hg) for the first time. The charge material of the blast furnace operations revealed Hg contents from 0.015 to 0.097mgkg(-1). In comparison, the Hg content of BFS varied between 0.006 and 20.8mgkg(-1) with a median of 1.63mgkg(-1), which indicates enrichment with Hg. For one site with a larger sample set (n=31), Hg showed a stronger correlation with the total non-calcareous carbon (C) including coke and graphite (r=0.695; n=31; p<0.001). It can be assumed that these C-rich compounds are hosting phases for Hg. The solubility of Hg was rather low and did not exceed 0.43% of total Hg. The correlation between the total Hg concentration and total amount of NH4NO3-soluble Hg was relatively poor (r=0.496; n=27; p=0.008) indicating varying hazard potentials of the different BFS. Finally, BFS is a mercury-containing waste and dumped BFS should be regarded as potentially mercury-contaminated sites. PMID:24290303

Földi, Corinna; Dohrmann, Reiner; Mansfeldt, Tim

2014-03-01

457

Research on abrasion law of coated cutters for high-speed dry milling  

NASA Astrophysics Data System (ADS)

The application of dry milling technology has completely eliminated the pollution of cutting fluid in machining. However, dry milling sets very high requirements on milling process and milling cutters, which has become the bottleneck in the popularization of dry milling technology. This research on the abrasion mechanism of TiAlN coated cutters for high-speed dry milling has indicated that, in high-speed dry milling, the abrasion of coated cutter is mainly in the form of crater. TiAlN coating has very strong oxidation resistance and adhesion resistance, so that the cutters have good abrasion resistance and crater abrasion resistance. In high-speed dry milling, a very thin layer of amorphous Al2O3 will be formed on the surface of TiAlN coating, forming hard inert protection film that acts as a good heat barrier. TiAlN coating has a low friction coefficient, which can effectively reduce the cutting force and cutting temperature, thus greatly prolonging the life of cutter. As an emerging coated cutter, TiAlN coated cutters exhibit incomparable excellent performance in high-speed dry milling. The research shows that factors such as coating thickness, milling speed, chip thickness and cutter conditions have important impact on the abrasion of TiAlN coated cutters.

Guo, Youdan

2011-05-01

458

Research on abrasion law of coated cutters for high-speed dry milling  

NASA Astrophysics Data System (ADS)

The application of dry milling technology has completely eliminated the pollution of cutting fluid in machining. However, dry milling sets very high requirements on milling process and milling cutters, which has become the bottleneck in the popularization of dry milling technology. This research on the abrasion mechanism of TiAlN coated cutters for high-speed dry milling has indicated that, in high-speed dry milling, the abrasion of coated cutter is mainly in the form of crater. TiAlN coating has very strong oxidation resistance and adhesion resistance, so that the cutters have good abrasion resistance and crater abrasion resistance. In high-speed dry milling, a very thin layer of amorphous Al2O3 will be formed on the surface of TiAlN coating, forming hard inert protection film that acts as a good heat barrier. TiAlN coating has a low friction coefficient, which can effectively reduce the cutting force and cutting temperature, thus greatly prolonging the life of cutter. As an emerging coated cutter, TiAlN coated cutters exhibit incomparable excellent performance in high-speed dry milling. The research shows that factors such as coating thickness, milling speed, chip thickness and cutter conditions have important impact on the abrasion of TiAlN coated cutters.

Guo, Youdan

2010-12-01

459

Effect of carbonitride precipitates on the abrasive wear behaviour of hardfacing alloy  

NASA Astrophysics Data System (ADS)

Hardfacing alloy of martensitic stainless steel expect higher abradability to be achieved through the addition of nitrogen being provided by the fine scale precipitation of complex carbonitride particles. Niobium and titanium as the most effective carbonitride alloying elements were added in the Fe-Cr13-Mn-N hardfacing alloy to get carbonitride precipitates. Carbonitride was systematically studied by optical microscopy, scanning electronic microscopy and energy spectrum analysis. Abrasive wear resistance of hardfacing alloy in as-welded and heat-treated conditions was tested by using the belt abrasion test apparatus where the samples slide against the abrasive belt. It is found that carbonitride particles in the hardfacing alloy are complex of Cr, Ti and Nb distributing on the grain boundary or matrix of the hardfacing alloy with different number and size in as-welded and heat-treated conditions. A large number of carbonitrides can be precipitated with very fine size (nanoscale) after heat treatment. As a result, the homogeneous distribution of very fine carbonitride particles can significantly improve the grain-abrasion wear-resisting property of the hardfacing alloy, and the mass loss is plastic deformation with minimum depth of grooving by abrasive particles and fine delamination.

Yang, Ke; Yu, Shengfu; Li, Yingbin; Li, Chenglin

2008-06-01

460

Note: A table-top blast driven shock tube  

NASA Astrophysics Data System (ADS)

The prevalence of blast-induced traumatic brain injury in conflicts in Iraq and Afghanistan has motivated laboratory scale experiments on biomedical effects of blast waves and studies of blast wave transmission properties of various materials in hopes of improving armor design to mitigate these injuries. This paper describes the design and performance of a table-top shock tube that is more convenient and widely accessible than traditional compression driven and blast driven shock tubes. The design is simple: it is an explosive driven shock tube employing a rifle primer that explodes when impacted by the firing pin. The firearm barrel acts as the shock tube, and the shock wave emerges from the muzzle. The small size of this shock tube can facilitate localized application of a blast wave to a subject, tissue, or material under test.

Courtney, Michael W.; Courtney, Amy C.

2010-12-01

461

A Table-top Blast Driven Shock Tube  

E-print Network

The prevalence of blast-induced traumatic brain injury in conflicts in Iraq and Afghanistan has motivated laboratory scale experiments on biomedical effects of blast waves and studies of blast wave transmission properties of various materials in hopes of improving armor design to mitigate these injuries. This paper describes the design and performance of a table-top shock tube that is more convenient and widely accessible than traditional compression driven and blast driven shock tubes. The design is simple: it is an explosive driven shock tube employing a rifle primer which explodes when impacted by the firing pin. The firearm barrel acts as the shock tube, and the shock wave emerges from the muzzle. The small size of this shock tube can facilitate localized application of a blast wave to a subject, tissue, or material under test.

Courtney, Michael; 10.1063/1.3518970

2011-01-01

462

Considerations on the European Standard EN 14157 Test Methods: Abrasion Resistance of Natural Stones Used for Flooring in Buildings  

NASA Astrophysics Data System (ADS)

In Europe, the Wide Wheel abrasion (WWA) test and the Böhme abrasion (BA) test are among the most widely used standard test methods for determining abrasion resistance of natural stones, the former being the reference test method in EN 14157 Standard. However, it is stated in the Annex-A (Informative) of EN 14157 Standard that very limited data are available to provide correlations between these two test methods. To be able to fill this gap, in this study, 25 different natural stones belonging to sedimentary, metamorphic and igneous groups were tested for their abrasion resistance as well as physico-mechanical properties. Also, for a better interpretation of abrasion resistance characteristics of the tested stone materials, relationships between abrasion resistance and physico-mechanical properties were statistically examined. A statistically significant linear correlation ( R 2 = 0.85; P value = 0.000) was established between the WWA test and the BA test, which could be used in practice for converting the measured abrasion resistance values from one testing method to another. It was also found that the correlation between these two test methods improved significantly ( R 2 = 0.93; P value = 0.001) when relatively high-porosity stone materials (porosity ?1%) were separately evaluated. Both methods of abrasion resistance employed in the present study showed statistically significant linear correlations with uniaxial compressive strength and Brazilian tensile strength, the former proving to be a more influencing parameter on resistance to abrasion. Also, from the point view of representing actual abrasion mechanism of stone materials in practice, the necessity of simulating multi-directional foot traffic in abrasion testing methods was discussed. In this respect, the reference test method in the EN 14157 Standard was criticized for not fully meeting this requirement. It was also pointed out that the reference method could have some drawbacks when applied to coarse-grained granitic rocks having cleavable minerals such as plagioclase and orthoclase feldspars.

Karaca, Z.; Günes Y?lmaz, N.; Goktan, R. M.

2012-01-01

463

[Prophylaxis pastes--the new abrasive Perlit compared to conventional polishing substances].  

PubMed

Perlit is a new dental abrasive, based on volcanic silica. It has a flat, irregular disc-shaped structure which fractures readily in use. Individual discs tend to become oriented parallel to the tooth surface during use while the rough edges also become rounded. A Perlit-based prophylactic paste thus produces polished surfaces although it also has excellent cleaning properties on both enamel and dentin when used with either rubber polishing cups or bristle brushes. The Perlit-based prophy paste, Cleanic, yielded the best results when compared to other prophy pastes during laboratory test scored with the Prophylaxis Paste Index (PPI: Cleaning efficacy: [Abrasivity x Surface roughness]). Consequently, Perlit-based prophy pastes can be used initially as cleaning pastes and the same portion will subsequently polish the dental surfaces as well. Thus Perlit nullifies the rule that an efficient cleaning paste will be abrasive and must produce a roughened dental surface. PMID:7855578

Lutz, F; Imfeld, T; Schüpbach, P

1995-01-01

464

Comparison of methods for quantifying dental wear caused by erosion and abrasion.  

PubMed

Various methods have been applied to evaluate the effect of erosion and abrasion. So, the aim of this study was to check the applicability of stylus profilometry (SP), surface hardness (SH) and focus-variation 3D microscopy (FVM) to the analysis of human enamel and dentin subjected to erosion/abrasion. The samples were randomly allocated into four groups (n = 10): G1-enamel/erosion, G2-enamel/erosion plus abrasion, G3-dentin/erosion, and G4-dentin/erosion plus abrasion. The specimens were selected by their surface hardness, and they were subjected to cycles of demineralization (Coca-Cola®-60 s) and remineralization (artificial saliva-60 min). For groups G2 and G4, the remineralization procedures were followed by toothbrushing (150 strokes). The above cycle was repeated 3×/day during 5 days. The samples were assessed using SH, SP, and FVM. For each substrate, the groups were compared using an unpaired t-test, and Pearson correlation coefficients were calculated (? = 5%). For enamel, both profilometry technique showed greater surface loss when the erosion and abrasion processes were combined (P <0.05). The correlation analysis did not reveal any relationships among SH, SP, and FVM to G2 and G4. There were significant correlation coefficients (-0.70 and -0.67) for the comparisons between the FVM and SH methods in enamel and dentin, respectively, in G1 and G3. Choosing the ideal technique for the analysis of erosion depends on the type of dental substrate. SP was not sufficiently sensitive to measure the effects on dentin of erosion or erosion/abrasion. However, SP, FVM and SH were adequate for the detection of tissue loss and demineralization in enamel. PMID:23129538

Passos, Vanara F; Melo, Mary A S; Vasconcellos, Andréa Araújo; Rodrigues, Lidiany K A; Santiago, Sérgio L

2013-02-01

465

Abrasion Testing of Candidate Outer Layer Fabrics for Lunar EVA Space Suits  

NASA Technical Reports Server (NTRS)

During the Apollo program, the space suit outer layer fabrics were severely abraded after just a few Extravehicular Activities (EVAs). For example, the Apollo 12 commander reported abrasive wear on the boots, which penetrated the outer layer fabric into the thermal protection layers after less than eight hours of surface operations. Current plans for the Constellation Space Suit Element require the space suits to support hundreds of hours of EVA on the Lunar surface, creating a challenge for space suit designers to utilize materials advances made over the last forty years and improve upon the space suit fabrics used in the Apollo program. A test methodology has been developed by the NASA Johnson Space Center Crew and Thermal Systems Division for establishing comparative abrasion wear characteristics between various candidate space suit outer layer fabrics. The abrasion test method incorporates a large rotary drum tumbler with rocks and loose lunar simulant material to induce abrasion in fabric test cylinder elements, representative of what might occur during long term planetary surface EVAs. Preliminary materials screening activities were conducted to determine the degree of wear on representative space suit outer layer materials and the corresponding dust permeation encountered between subsequent sub-layers of thermal protective materials when exposed to a simulated worst case eight hour EVA. The test method was used to provide a preliminary evaluation of four candidate outer layer fabrics for future planetary surface space suit applications. This paper provides a review of previous abrasion studies on space suit fabrics, details the methodologies used for abrasion testing in this particular study, shares the results of the testing, and provides recommendations for future work.

Mitchell, Kathryn

2009-01-01

466

Mine blast injuries: ocular and social aspects  

PubMed Central

BACKGROUND/AIMS—Landmines have long been used in conventional warfare. These are antipersonnel mines which continue to injure people long after a ceasefire without differentiating between friend or foe, soldier or civilian, women or children. This study focuses on Afghan non-combatants engaged in mine clearing operations in Afghanistan in the aftermath of the Russo-Afghan war. The patterns and types of injuries seen are described and experiences in their management, ways, and means to prevent them, and recommendations for the rehabilitation of the affected individuals are given.?METHODS—It is a retrospective and analytical study of 84 patients aged 19-56 years who sustained mine blast injuries during mine clearing operations in Afghanistan from November 1992 to January 1996. The study was carried out at a military hospital with tertiary care facilities. The patients were divided into three groups on the basis of their injuries. Group 1 required only general surgical attention, group 2 sustained only ocular injuries, while group 3 had combined ocular and general injuries. Patients in groups 2 and 3 were treated in two phases. The first phase aimed at immediate restoration of the anatomy, while restoration of function wherever possible was done in subsequent surgical procedures in the second phase.?RESULTS—It was observed that 51 out of 84 patients (60.7%) had sustained ocular trauma of a variable degree as a result of the blasts. The mean age of the victims was 29 years and they were all male. A total of 91 eyes of 51 patients (89.2%) had been damaged. Bilaterality of damage was seen in 40 (78.4%) patients. Most, 34 (37.3%), eyes became totally blind (NPL). Only a few escaped with injury mild enough not to impair vision. Foreign bodies, small and multiple, were found in the majority of eyes; most, however, were found in the anterior segment, and posterior segment injuries were proportionally less.?CONCLUSIONS—The prevalence of blindness caused by mine blast injuries is quite high. The resulting psychosocial trauma to the patients and their families is tremendous and has not been adequately highlighted. These injuries are a great drain on the country's resources. Enforcement of preventive measures and the use of protective gear and sophisticated equipment by the mine clearing personnel would prove to be far more economical in terms of human life as well as medical and economic resources. There is also need for greater attention towards the establishment of support groups and rehabilitation programmes for these individuals.?? PMID:10837390

Muzaffar, W.; Khan, M. D.; Akbar, M; Khan, M. D.; Malik, A. M.; Durrani, O.

2000-01-01

467

Experience with bandage contact lenses for the treatment of corneal abrasions in a combat environment.  

PubMed

Corneal abrasions are a common result of eye trauma. Although they usually heal well with conservative therapy, they still tend to be a source of morbidity, in terms of pain and lost work time. We reviewed 15 cases in which a bandage contact lens was used as the primary treatment for corneal abrasions in an austere environment. We found that the lenses performed well, except for patients who had undisclosed risk factors for corneal ulcers at the outset. When used for carefully selected patients, bandage contact lenses may be a highly effective treatment modality that allows for rapid return to duty. PMID:17484314

Buglisi, Joseph A; Knoop, Kevin J; Levsky, Marc E; Euwema, Michael

2007-04-01

468

Development of a water-jet concrete-cutting system. Volume 2. Abrasive water-jet systems. Final report  

Microsoft Academic Search

This report represents all testing and analysis of abrasive waterjet cutting technology performed by Flow Industries Inc. under EPRI research contract RP7860-1. Prior work, described in Volume 1, emphasized pure waterjet technology for purposes of cutting roadgrade substrates. Because of inadequate cutting, abrasive augmented waterjets at reduced pressures were pursued in order to meet this contract's objective of developing a

M. Hashish; J. M. Reichman; M. C. McDonald

1984-01-01

469

An analytical model of the effect of particle size distribution on the surface profile evolution in abrasive jet micromachining  

Microsoft Academic Search

An analytical model to estimate the spatial distribution of erosive efficacy across the mask opening in the abrasive jet micromachining (AJM) of substrates is presented. A closed form analytical expression is derived which allows the erosive efficacy in the vicinity of the mask edge to be estimated as a function of the measured abrasive particle size distribution and the width

A. Ghobeity; D. Ciampini; M. Papini

2009-01-01

470

Reactive Blast Waves from Composite Charges  

SciTech Connect

Investigated here is the performance of composite explosives - measured in terms of the blast wave they drive into the surrounding environment. The composite charge configuration studied here was a spherical booster (1/3 charge mass), surrounded by aluminum (Al) powder (2/3 charge mass) at an initial density of {rho}{sub 0} = 0.604 g/cc. The Al powder acts as a fuel but does not detonate - thereby providing an extreme example of a 'non-ideal' explosive (where 2/3 of the charge does not detonate). Detonation of the booster charge creates a blast wave that disperses the Al powder and ignites the ensuing Al-air mixture - thereby forming a two-phase combustion cloud embedded in the explosion. Afterburning of the booster detonation products with air also enhances and promotes the Al-air combustion process. Pressure waves from such reactive blast waves have been measured in bomb calorimeter experiments. Here we describe numerical simulations of those experiments. A Heterogeneous Continuum Model was used to model the dispersion and combustion of the Al particle cloud. It combines the gasdynamic conservation laws for the gas phase with a dilute continuum model for the dispersed phase, as formulated by Nigmatulin. Inter-phase mass, momentum and energy exchange are prescribed by phenomenological models of Khasainov. It incorporates a combustion model based on mass conservation laws for fuel, air and products; source/sink terms are treated in the fast-chemistry limit appropriate for such gasdynamic fields, along with a model for mass transfer from the particle phase to the gas. The model takes into account both the afterburning of the detonation products of the booster with air, and the combustion of the Al particles with air. The model equations were integrated by high-order Godunov schemes for both the gas and particle phases. Adaptive Mesh Refinement (AMR) was used to capture the energy-bearing scales of the turbulent flow on the computational grid, and to track/resolve reaction zones. Numerical simulations of the explosion fields from 1.5-g and 10-kg composite charges were performed. Computed pressure histories (red curve) are compared with measured waveforms (black curves) in Fig. 1. Comparison of these results with a waveform for a non-combustion case in nitrogen (blue curve) demonstrates that a reactive blast wave was formed. Cross-sectional views of the temperature field at various times are presented in Fig. 2, which shows that the flow is turbulent. Initially, combustion occurs at the fuel-air interface, and the energy release rate is controlled by the rate of turbulent mixing. Eventually, oxidizer becomes distributed throughout the cloud via ballistic mixing of the particles with air; energy release then occurs in a distributed combustion mode, and Al particle kinetics controls the energy release rate. Details of the Heterogeneous Continuum Model and results of the numerical simulations of composite charge explosions will be described in the paper.

Kuhl, A L; Bell, J B; Beckner, V E

2009-10-16

471

Blast mitigation capabilities of aqueous foam.  

SciTech Connect

A series of tests involving detonation of high explosive blanketed by aqueous foam (conducted from 1982 to 1984) are described in primarily terms of recorded peak pressure, positive phase specific impulse, and time of arrival. The investigation showed that optimal blast mitigation occurs for foams with an expansion ratio of about 60:1. Simple analyses representing the foam as a shocked single phase mixture are presented and shown inadequate. The experimental data demonstrate that foam slows down and broadens the propagated pressure disturbance relative to a shock in air. Shaped charges and flyer plates were evaluated for operation in foam and appreciable degradation was observed for the flyer plates due to drag created by the foam.

Hartman, William Franklin; Larsen, Marvin Elwood; Boughton, Bruce A.

2006-02-01

472

LTC vacuum blasting maching (concrete): Baseline report: Greenbook (Chapter)  

SciTech Connect

The LTC shot blast technology was tested and is being evaluated at Florida International University (FIU) as a baseline technology. In conjuction with FIU`s evaluation of efficiency and cost, this report covers the evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The LTC 1073 Vacuum Blasting Machine uses a high-capacity, direct-pressure blasting system which incorporates a continuous feed for the blast media. The blast media cleans the surface within the contained brush area of the blast. It incorporates a vacuum system which removes dust and debris from the surface as it is blasted. The safety and health evaluation during the testing demonstration focused on two main areas of exposure: dust and noise. Dust exposure during maintenance activities was minimal, but due to mechanical difficulties dust monitoring could not be conducted during operation. Noise exposure was significant. Further testing for each of these exposures is recommended because of the outdoor environment where the testing demonstration took place. This may cause the results to be inaccurate. It is feasible that the dust and noise levels will be higher in an enclosed environment. In addition, other safety and health issues found were ergonomics, heat stress, tripping hazards, electrical hazards, lockout/tagout, and arm-hand vibration.

NONE

1997-07-31

473

Mercury in dumped blast furnace sludge  

NASA Astrophysics Data System (ADS)

Blast furnace sludge (BFS) is a waste generated in the production of pig iron and was dumped in sedimentation ponds. As these wastes often contain high contents of zinc, lead, cadmium, and arsenic, significant hazards to environmental surroundings may arise from former BFS sedimentation ponds. Sixty-five samples from seven BFS locations in Europe were investigated regarding the toxic element mercury (Hg) for the first time. The charge material of the blast furnace operations (coke, iron ores, and additives such as olivine, bauxite, ilmenite and gravels) revealed Hg contents from 0.015 to 0.093 mg kg-1. In comparison, the Hg content of BFS varied between 0.006 and 20.8 mg kg-1 with a median of 1.63 mg kg-1, which indicates enrichment with Hg. For one site with a larger sample set (n = 31), Hg showed a stronger correlation with the total non-calcareous carbon (C) including coke and graphite (r = 0.695; n = 31; p < 0.001). It can be assumed that these C-rich compounds are hosting phases for Hg. The solubility of Hg was rather low and did not exceed 0.43% of total Hg. The correlation between the total Hg concentration and total amount of NH4NO3-soluble Hg was relatively poor (r = 0.496; n = 27; p = 0.008) indicating varying hazard potentials of the different BFS. Consequently, BFS is a mercury-containing waste and dumped BFS should be regarded as potentially mercury-contaminated sites.

Földi, Corinna

2014-05-01

474

Sedimentation of the Late Triassic Higham Grit in a south Saskatchewan/Platte River-type braided stream complex, southeastern Idaho and western Wyoming  

SciTech Connect

The Late Triassic Higham Grit in southeastern Idaho and western Wyoming is comprised predominantly of coarse to medium-grained sandstone and pebble conglomerate with minor mudstone. Lithofacies present include: massive to crudely horizontally bedded pebbly conglomerate (Gm), trough crossbedded sandstone (St), planar crossbedded sandstone (Sp), horizontally stratified sandstone (Sh), ripple crosslaminated sandstone (Sr), and finely laminated sandstone and mudstone (Fl). Deposition occurred in a South Saskatchewan/Platte River-type braided fluvial complex with the development of longitudinal bars and gravel lags (Gm), straight-crested transverse bars (Sp), and sinuous-crested transverse bars and dunes (St). Periodic, high-velocity flow resulted in development of upper flow regime plane beds (Sh). Minor episodes of flood plain inundation produced overbank deposits (Fl). Application of the South Saskatchewan and Platte River braided stream models to the Higham Grit is in good agreement with provenance studies (Schmitt and Hazen, in preparation) which postulate a sediment source area in the Ancestral Rocky Mountains uplift, a distance of 500-700 km to the southeast. Sediment transport distances in both the South Saskatchewan and Platte braided fluvial systems closely approximate this distance.

Schmitt, J.G.; Hazen, D.R.

1987-01-01

475

Compressive strength after blast of sandwich composite materials.  

PubMed

Composite sandwich materials have yet to be widely adopted in the construction of naval vessels despite their excellent strength-to-weight ratio and low radar return. One barrier to their wider use is our limited understanding of their performance when subjected to air blast. This paper focuses on this problem and specifically the strength remaining after damage caused during an explosion. Carbon-fibre-reinforced polymer (CFRP) composite skins on a styrene-acrylonitrile (SAN) polymer closed-cell foam core are the primary composite system evaluated. Glass-fibre-reinforced polymer (GFRP) composite skins were also included for comparison in a comparable sandwich configuration. Full-scale blast experiments were conducted, where 1.6×1.3?m sized panels were subjected to blast of a Hopkinson-Cranz scaled distance of 3.02?m?kg(-1/3), 100?kg TNT equivalent at a stand-off distance of 14?m. This explosive blast represents a surface blast threat, where the shockwave propagates in air towards the naval vessel. Hopkinson was the first to investigate the characteristics of this explosive air-blast pulse (Hopkinson 1948 Proc. R. Soc. Lond. A 89, 411-413 (doi:10.1098/rspa.1914.0008)). Further analysis is provided on the performance of the CFRP sandwich panel relative to the GFRP sandwich panel when subjected to blast loading through use of high-speed speckle strain mapping. After the blast events, the residual compressive load-bearing capacity is investigated experimentally, using appropriate loading conditions that an in-service vessel may have to sustain. Residual strength testing is well established for post-impact ballistic assessment, but there has been less research performed on the residual strength of sandwich composites after blast. PMID:24711494

Arora, H; Kelly, M; Worley, A; Del Linz, P; Fergusson, A; Hooper, P A; Dear, J P

2014-05-13

476

Proceedings of the eleventh annual symposium on explosives and blasting research  

SciTech Connect

These proceedings contain 26 papers presented at the conference. Topics relate to performance of explosives, blast wave propagation, charge malfunctions, building response to ground vibrations, tunnel excavations, detonator design, reduction of ground vibration, blast design, blast fragmentation measurement, and blast analysis. Most of the papers have been processed separately for inclusion on the data base.

NONE

1995-12-31

477

An assessment of environmental impacts of quarry-blasting operation: a case study in Istanbul, Turkey  

Microsoft Academic Search

This study evaluates the impacts resulting from quarry-blasting operation on nearby buildings and structures as it generates ground vibration, air blast, and fly rocks. In this paper, first blasting operation and its possible environmental effects are defined. Then the methods of blast-vibration prediction and commonly accepted criteria to prevent damage were introduced. A field experimental work was conducted to minimize

Cengiz Kuzu; Hasan Ergin

2005-01-01

478

Measurement of Blast Waves from Bursting Pressureized Frangible Spheres  

NASA Technical Reports Server (NTRS)

Small-scale experiments were conducted to obtain data on incident overpressure at various distances from bursting pressurized spheres. Complete time histories of blast overpressure generated by rupturing glass spheres under high internal pressure were obtained using eight side-on pressure transducers. A scaling law is presented, and its nondimensional parameters are used to compare peak overpressures, arrival times, impulses, and durations for different initial conditions and sizes of blast source. The nondimensional data are also compared, whenever possible, with results of theoretical calculations and compiled data for Pentolite high explosive. The scaled data are repeatable and show significant differences from blast waves generated by condensed high-explosives.

Esparza, E. D.; Baker, W. E.

1977-01-01

479

Evaluation of copper slag blast media for railcar maintenance  

NASA Technical Reports Server (NTRS)

Copper slag was tested as a blasting substitute for zirconium silicate which is used to remove paint from railroad cars. The copper slag tested is less costly, strips paint faster, is produced near the point of need, provides a good bonding surface for paint, and permits the operator to work in a more comfortable position, i.e., standing nearly erect instead of having to crouch. Outdoor blasting with the tested Blackhawk (20 to 40 mesh) copper slag is also environmentally acceptable to the State of Utah. Results of tests for the surface erosion rate with copper slag blasting are included.

Sagers, N. W.; Finlayson, Mack H.

1989-01-01

480

Hybrid S2/Carbon Epoxy Composite Armours Under Blast Loads  

NASA Astrophysics Data System (ADS)

Civil and military structures, such as helicopters, aircrafts, naval ships, tanks or buildings are susceptible to blast loads as terroristic attacks increases, therefore there is the need to design blast resistant structures. During an explosion the peak pressure produced by shock wave is much greater than the static collapse pressure. Metallic structures usually undergo large plastic deformations absorbing blast energy before reaching equilibrium. Due to their high specific properties, fibre-reinforced polymers are being considered for energy absorption applications in blast resistant armours. A deep insight into the relationship between explosion loads, composite architecture and deformation/fracture behaviour will offer the possibility to design structures with significantly enhanced energy absorption and blast resistance performance. This study presents the results of a numerical investigation aimed at understanding the performance of a hybrid composite (glass/carbon fibre) plate subjected to blast loads using commercial LS-DYNA software. In particular, the paper deals with numerical 3D simulations of damages caused by air blast waves generated by C4 charges on two fully clamped rectangular plates made of steel and hybrid (S2/Carbon) composite, respectively. A Multi Materials Arbitrary Lagrangian Eulerian (MMALE) formulation was used to simulate the shock phenomenon. For the steel plates, the Johnson-Cook material model was employed. For the composite plates both in-plane and out-of-plane failure criteria were employed. In particular, a contact tiebreak formulation with a mixed mode failure criteria was employed to simulate delamination failure. As for the steel plates the results showed that excellent correlation with the experimental data for the two blast load conditions in terms of dynamic and residual deflection for two different C4 charges. For the composite plates the numerical results showed that, as expected, a wider delamination damage was observed for the higher blast loads case. Widespread tensile matrix damage was experienced for both blast load cases, while only for 875 g blast load fiber failure damage was observed. This agrees well with the experimental data showing that the composite panel was not able to resist to the 875 g blast load.

Dolce, F.; Meo, Michele; Wright, A.; French, M.; Bernabei, M.

2012-06-01

481

Pediatric blast lung injury from a fireworks-related explosion.  

PubMed

Blast injuries related to explosions have been described in the literature but are uncommon in children. We describe a multisystem blast injury in a child resulting from a commercial firework-related explosion in her home. She presented with respiratory failure, shock, altered level of consciousness, and multiple orthopedic injuries. The patient required immediate stabilization and resuscitation in the emergency department and a prolonged hospitalization. This report reviews the spectrum of injuries that are seen in blast-related trauma and the emergency measures needed for rapid stabilization of these critical patients. PMID:22668665

Ratto, Jessica; Johnson, Bernadette K; Condra, Cole S; Knapp, Jane F

2012-06-01

482

Hot blast stove process model and model-based controller  

SciTech Connect

This paper describes the process model and model-based control techniques implemented on the hot blast stoves for the No. 7 Blast Furnace at the Inland Steel facility in East Chicago, Indiana. A detailed heat transfer model of the stoves is developed and verified using plant data. This model is used as part of a predictive control scheme to determine the minimum amount of fuel necessary to achieve the blast air requirements. The model is also used to predict maximum and minimum temperature constraint violations within the stove so that the controller can take corrective actions while still achieving the required stove performance.

Muske, K.R. [Villanova Univ., PA (United States). Dept. of Chemical Engineering; Howse, J.W.; Hansen, G.A.; Cagliostro, D.J. [Los Alamos National Lab., NM (United States). Computational Science Methods Group; Chaubal, P.C. [Inland Steel Industries, Inc., East Chicago, IN (United States). Research Labs.

1998-12-31

483

Measurement of Transmitted Blast Force-Time Histories  

NASA Astrophysics Data System (ADS)

A simple, reliable, and cost effective method is presented for the measurement of transmitted force behind a panel subjected to blast loads. Sensors were designed for a specific blast environment and successfully used to measure transmitted blast force behind solid polyethylene plates of thickness 0.125 and 0.25 inches. Experimental data was collected and examined to reveal consistent differences in the response of different thicknesses of otherwise identical panels. Finally, recommendations are made for future design, construction and use of similar sensors.

Langhorst, Benjamin; Cook, Corey; Schondel, James; Chu, Henry S.

2010-06-01

484

Measurement of transmitted blast force-time histories  

SciTech Connect

A simple, reliable, and cost effective method is presented for the measurement of transmitted force behind a panel subjected to blast loads. Sensors were designed for a specific blast environment and successfully used to measure transmitted blast force behind solid polyethylene plates of thickness 0.125 and 0.25 inches. Experimental data was collected and examined to reveal consistent differences in the response of different thicknesses of otherwise identical panels. Finally, recommendations are made for future design, construction and use of similar sensors.

Dr. Benjamin Langhorst; Corey Cook; James Schondel; Dr. Henry S. Chu

2010-03-01

485

Electrochemical metallization of abrasive materials and their physical-mechanical properties  

Microsoft Academic Search

In this work, the kinetics of molybdenum carbide electroplating from ionic melts on abrasive grains (diamond, silicon and\\u000a boron carbides) as a function of electrolysis parameters has been studied, and the physical, mechanical and service properties\\u000a of metallized materials have been evaluated.

V. V. Malyshev

1997-01-01

486

Methods for the determination of platinum group elements originating from the abrasion of automotive catalytic converters  

Microsoft Academic Search

Anthropogenic emission of platinum group elements (PGEs) from the abrasion of automotive catalytic converters into the environment has significantly increased. However, the concentration level of these PGEs (i.e. Pd, Pt, Rh) is still very low in the nature. Accordingly, their determination and speciation in various environmental compartments appears to be a challenging task for analytical chemists. The present review gives

László Bencs; Khaiwal Ravindra; René Van Grieken

2003-01-01

487

Soft tissue injuries (cuts, abrasions, blisters, burns, and bruises) are common occurrences for the  

E-print Network

is the connective tissue under the dermis; binds skin loosely to underlying tissue (e.g. fasciae, muscle, bone, etcSoft tissue injuries (cuts, abrasions, blisters, burns, and bruises) are common occurrences and nutrients to the dermis via capillaries. Below the subcutaneous layer there are other deeper tissues

Virginia Tech

488

Modelling the erosion rate in micro abrasive air jet machining of glasses  

Microsoft Academic Search

Micro abrasive jet machining (MAJM) is an economical and efficient technology for micro-machining of brittle material like glasses. The erosion of brittle materials by solid micro-particles is a complex process in which material is removed from the target surface by brittle fractures. The rate of material removal is one of the most important quantities for a machining process. Predictive mathematical

J. M. Fan; C. Y. Wang; J. Wang

2009-01-01

489

An in situ Investigation into the Abrasion of Eroded Dental Hard Tissues by a Whitening Dentifrice  

Microsoft Academic Search

This crossover study aimed to investigate abrasion of previously eroded hard dental tissues by a whitening dentifrice compared to a regular dentifrice. After a 3-day lead-in period, 14 volunteers were randomly assigned to use one of the toothpastes while wearing a removable appliance, containing 3 enamel and 3 root dentine slabs on each side. On the first day salivary pellicle

C. P. Turssi; J. J. Faraoni; A. L. Rodrigues Jr.; M. C. Serra

2004-01-01

490

Two waves of neutrophil emigration in response to corneal epithelial abrasion: Distinct adhesion molecule requirements  

Technology Transfer Automated Retrieval System (TEKTRAN)

PURPOSE: Corneal abrasion results in an inflammatory response characterized by leukocyte emigration into the corneal stroma. Adhesion molecules play a critical role in leukocyte emigration to wound sites, but differences are evident in different vascular beds. In this study, the contributions of two...

491

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

E-print Network

, kinetic energy distribution. NOMENCLATURE AWJ Abrasive water jet CD Discharge coefficient, - Cdrag Drag coefficient, - d Diameter, mm E Energy, J g Gravity, g = 9.81 m/s2 h Specific enthalpy, J / kg L* foc manufacturing methods like laser cutting and electro-discharge machining. To achieve exacter parts, a machine

492

Effect of abrasive wear on the tensile strength of steel wire rope  

Microsoft Academic Search

Known amounts of external abrasive wear were introduced into a new 6-strand steel wire rope and the effects of this wear on the tensile strength of the rope examined against the rope discard criteria for wear stated in ISO 4309: 1990 and other selected international standards. The variations of strength with degree of wear in the test rope were compared

A. R. T. de Silva; Long Woon Fong

2002-01-01

493

The effects of compressive stresses on the abrasion of diamond coatings  

Microsoft Academic Search

The effects of high biaxial compressive stresses on the abrasion of diamond coatings by diamond particles were evaluated using an atomic force microscope (AFM).The specimens subjected to testing were diamond coatings deposited on cemented carbide substrates, receiving high biaxial stresses due to thermal expansion mismatch, and freestanding stress-free diamond coatings. It is shown that the highly stressed coatings obtain a

Rickard Gĺhlin; Arto Alahelisten; Staffan Jacobson

1996-01-01

494

Erosion and abrasion of chromium carbide based cermets produced by different methods  

Microsoft Academic Search

This paper is on comparison of the abrasive and erosive wear resistance of chromium carbide based and nickel bonded cermets prepared by two different methods: conventional powder metallurgy sintering and the new developed one—reactive carburizing sintering. The nickel content was varied at the weight percents of 10, 20 and 30%. Results indicate that sintering process and microstructural parameters influence materials

Irina Hussainova; Juri Pirso; Maksim Antonov; Kristjan Juhani; Sergei Letunovitš

2007-01-01

495

Laser abrasion for cosmetic and medical treatment of facial actinic damage  

SciTech Connect

Previous studies have shown the carbon dioxide (CO/sub 2/) laser to be effective in the treatment of actinic cheilitis. After CO/sub 2/ laser abrasion, normal skin and marked cosmetic improvement of the lip were noted. In our study, twenty-three patients were treated with CO/sub 2/ laser abrasions for cosmetic improvement of facial lines and actinic changes. Pre- and postoperative histopathologic examinations were made on two patients. Preoperative examination of specimens from actinically damaged skin showed atypical keratinocytes in the basal layer of the epidermis, with overlying dense compact orthokeratosis and parakeratosis. Abundant solar elastosis was seen in the papillary dermis. Postoperative histologic specimens showed a normal-appearing epidermis with fibrosis in the papillary dermis and minimal solar elastosis (about four weeks after laser treatment). At present, various modalities are available for the regeneration of the aged skin, including chemical peels and dermabrasion. Significantly fewer complications were noted with CO/sub 2/ laser abrasion than with these methods. Thus, CO/sub 2/ laser abrasion can be useful in the cosmetic and medical treatment of the aged skin. Marked clinical and histologic improvement has been demonstrated.

David, L.M.; Lask, G.P.; Glassberg, E.; Jacoby, R.; Abergel, R.P.

1989-06-01

496

Platelet response to corneal abrasion is necessary for acute inflammation and efficient re-epithelialization  

Technology Transfer Automated Retrieval System (TEKTRAN)

Purpose: Adhesion molecules play a critical role in leukocyte emigration to wound sites, but differences are evident in different vascular beds. This study investigates the contributions of P-selectin to neutrophil emigration into the cornea following central epithelial abrasion. Methods: Re-epithel...

497

Parametric Study to Correlate the Applied Factors and Abrasive Wear Resistance of HVOF Coating  

NASA Astrophysics Data System (ADS)

Co-Ni-base powder was modified with the addition of CeO2 to study the effect of CeO2 addition on microstructure, hardness, and abrasive wear behavior of the unmodified (without CeO2) and modified (with CeO2) HVOF sprayed coatings. To investigate the abrasive wear behavior of coatings statistical response surface methodology (RSM) with four factors such as load, abrasive size, sliding distance, and temperature with three levels of each factor were used. Analysis of variance (ANOVA) was carried out to determine the significant factors and their interactions. Thus abrasive wear model was developed in terms of main factors and their significant interactions. The validity of the model was evaluated by conducting experiments under different wear conditions. A comparison of modeled and experimental results showed 2-8% error. The wear resistance of coatings increased with the addition of CeO2. This is due to increase in hardness with the addition of CeO2 in Co-Ni-base coatings.

Sharma, Satpal

2012-12-01

498

Martian and Terrestrial Rock Abrasion from Wind Tunnel and Field Studies  

NASA Technical Reports Server (NTRS)

Earth and Mars exhibit ventifacts, rocks that have been abraded by saltating sand. Previous theoretical and laboratory studies have determined abrasion susceptibilities of rocks as a function of sand type and impact angle and rock material strengths. For the last two years we have been engaged in wind tunnel and field studies to better understand the fundamental factors which control and influence rock abrasion and ventifact formation on Earth and Mars. In particular, we are examining: 1) What types of rocks (composition, texture, and shape) preferentially erode and what are the relative rates of one type vs. another? 2) What are the controlling factors of the aeolian sand cloud (flux, particle speed, surface roughness, etc) which favor rock abrasion?, 3) How do specific ventifact characteristics tie into their mode of formation and rock properties? We find several important factors: 1) Initial rock shape controls the rate of abrasion, with steeper faces abrading faster than shallower ones. The relationship is partly dependent on angle-dependent flux (proportional to sin[theta]) but exhibits additional non-linear effects from momentum transfer efficiency and rebound effects that vary with incidence angle. 2) Irregular targets with pits or grooves abrade at greater rates than targets with smooth surfaces, with indentations generally enlarging with time. Surfaces become rougher with time. 3) Targets also abrade via slope retreat, which is roughly dependent on the slope of the front face. The formation of basal sills is common, as observed on terrestrial and Martian ventifacts.

Bridges, N. T.; Greeley, R.; Eddlemon, E.; Laity, J. E.; Meyer, C.; Phoreman, J.; White, B. R.

2003-01-01

499

Abrasive Wear Behavior of Heat-Treated ABC-Silicon Carbide Xiao Feng Zhang,*,  

E-print Network

Abrasive Wear Behavior of Heat-Treated ABC-Silicon Carbide Xiao Feng Zhang,*, Gun Y. Lee, Da Chen and Engineering, Shanghai Jiao Tong University, Shanghai 200030, China Hot-pressed silicon carbide, containing ce- ramics, hot-pressed, monolithic silicon carbide (SiC) may be one of the most attractive. Recent

Ritchie, Robert

500

Erosion of enamel by non-carbonated soft drinks with and without toothbrushing abrasion  

Microsoft Academic Search

Objective To investigate how enamel loss due to erosion, and due to cycling of erosion and abrasion, depends on compositional parameters of soft drinks, and particularly whether the thickness of the erosive softened layer is a function of drink composition.Setting University dental hospital research laboratory in the UK, 2004.Materials and methods Six drinks were chosen based on their popularity and

C A Hemingway; D M Parker; M Addy; M E Barbour

2006-01-01