These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Soybean seedlings tolerate abrasion from air-propelled grit  

Technology Transfer Automated Retrieval System (TEKTRAN)

New tools for controlling weeds would be useful for soybean production in organic systems. Air-propelled abrasive grit is one such tool that performs well for in-row weed control in corn, but crop safety in soybean is unknown. We examined responses to abrasion by corn-cob grit of soybean seedlings a...

2

30 CFR 58.610 - Abrasive blasting.  

Code of Federal Regulations, 2010 CFR

...with the miner outside the device. (b) Underground areas of underground mines. Silica sand or other materials containing more than 1 percent free silica shall not be used as an abrasive substance in abrasive blasting. [59 FR 8327,...

2010-07-01

3

30 CFR 72.610 - Abrasive blasting.  

Code of Federal Regulations, 2010 CFR

...with the miner outside the device. (b) Underground areas of underground mines. Silica sand or other materials containing more than 1 percent free silica shall not be used as an abrasive substance in abrasive blasting. [59 FR 8327,...

2010-07-01

4

Air-propelled abrasive grit for postemergence in-row weed control in field corn  

Technology Transfer Automated Retrieval System (TEKTRAN)

Organic growers need additional tools for weed control. A new technique involving abrasive grit propelled by compressed air was tested in field plots. Grit derived from corn cobs was directed at seedlings of summer annual weeds growing at the bases of corn plants when the corn was at differing early...

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

Alumina grit blasting parameters for surface preparation in the plasma spraying operation  

NASA Astrophysics Data System (ADS)

This paper examines how the grit blasting process influences the surface roughness of different sub-strates, the grit residue, and the grit erosion. The influence of grit blasting conditions on induced sub-strate residual stresses is also discussed. Aluminum alloy, cast iron, and hard steel were blasted with white alumina grits of 0.5,1, and 1.4 mm mean diameters. Grit blasting was performed using either a suction-type or a pressure-type machine equipped with straight nozzles made of B4C. The influence of the follow-ing parameters was studied: grit blasting distance (56 to 200 mm), blasting time (3 to 30 s), angle between nozzle and blasted surface (30°, 60°, 90°), and blasting pressure (0.2 to 0.7 MPa). The roughness of the substrate was characterized either by using a perthometer or by image analysis. The grit residue remain-ing at the blasted surface was evaluated after cleaning by image analysis. The residual stresses induced by grit blasting were determined by using the incremental hole drilling method and by measuring the de-flection of grit-blasted beams. Grit size was determined to be the most important influence on roughness. The average values of Ra and Rt and the percentage of grit residue increased with grit size as well as the depth of the plastic zone under the substrate. An increase of the pressure slightly increased the values of Äa and Rt but also promoted grit breakdown and grit residue. A blasting time of 3 to 6 s was sufficient to obtain the highest roughness and limit the grit breakdown. The residual stresses generated under the blasted surface were compressive, and the depth of the affected zone depended on the grit diameter, the blasting pressure, and the Young’s modulus of the substrate. More-over, the maximum residual stress was reached at the limit of the plastic zone (i.e., several tenths of a mil-limeter below the substrate surface).

Mellali, M.; Grimaud, A.; Leger, A. C.; Fauchais, P.; Lu, J.

1997-06-01

7

PAGMan - propelled abrasive grit to manage weeds in soybean and corn  

Technology Transfer Automated Retrieval System (TEKTRAN)

New tools for controlling weeds would be useful for soybean and corn production in organic systems or in systems in which weeds developed resistance to multiple herbicides. Here we report on two developments: (i) the safety to soybean seedlings of using air-propelled abrasive grit (PAG) for managing...

8

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

9

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 {minus}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. {copyright} {ital 1998 American Institute of Physics.}

Powell, G.L.; Hallman, R.L. Jr.; Cox, R.L. [Oak Ridge Centers for Manufacturing Technologies, P.O. Box 2009, Oak Ridge, Tennessee 37831-8096 (United States)

1998-06-01

10

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

11

Acid etching and plasma sterilization fail to improve osseointegration of grit blasted titanium implants.  

PubMed

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

Saksř, Mikkel; Jakobsen, Stig S; Saksř, Henrik; Baas, Jřrgen; Jakobsen, Thomas; Sřballe, Kjeld

2012-01-01

12

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

13

Atmospheric particulate emissions from dry abrasive blasting using coal slag  

SciTech Connect

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

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

2006-08-15

14

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

15

Recycling contaminated spent blasting abrasives in Portland cement mortars using solidification/stabilization technology  

SciTech Connect

The use of abrasive blasting to remove paint containing lead, cadmium, and chromium from steel bridges is producing contaminated spent blasting abrasives that may be classified as hazardous by the Environmental Protection Agency based upon toxicity. Under such a situation, the transportation and disposal of the spent abrasives is difficult and costly. A potentially inexpensive and practical solution to this problem is to recycle the contaminated spent blasting abrasives at the construction site in an environmentally safe manner using solidification/stabilization technology. This research investigates the use of Portland cement to solidify/stabilize the spent abrasives and produce a usable construction material.

Salt, B.K.; Garner, A.G.; Fowler, D.W.; Loehr, R.C.; Carrasquillo, R.L. [Univ. of Texas, Austin, TX (United States). Dept. of Civil Engineering

1996-12-31

16

Surface assessment and modification of concrete using abrasive blasting  

NASA Astrophysics Data System (ADS)

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

Millman, Lauren R.

17

Recycling contaminated spent blasting abrasives in Portland cement mortars using solidification\\/stabilization technology. Final research report  

Microsoft Academic Search

The use of abrasive blasting to remove lead-based paint from steel bridges produces contaminated spent blasting abrasives that may be classified as hazardous by the Environmental Protection Agency. If the spent abrasives leach lead, chromium, and cadmium greater than the EPA limits, the spent abrasives are classified as hazardous and must be rendered nonhazardous prior to disposal. An alternative to

B. K. Salt; R. L. Carrasquillo; R. C. Loehr; D. W. Fowler

1995-01-01

18

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

19

Recycling contaminated spent blasting abrasives in Portland cement mortars using solidification/stabilization technology. Final research report  

SciTech Connect

The use of abrasive blasting to remove lead-based paint from steel bridges produces contaminated spent blasting abrasives that may be classified as hazardous by the Environmental Protection Agency. If the spent abrasives leach lead, chromium, and cadmium greater than the EPA limits, the spent abrasives are classified as hazardous and must be rendered nonhazardous prior to disposal. An alternative to disposing of spent blasting abrasives is to recycle them in an environmentally sound application. This study investigates the feasibility of recycling spent blasting abrasives in portland cement mortars using solidification/stabilization technology to produce a usable construction material. Field application guidelines for recycling spent blasting abrasives in portland cement mortars are established based upon the results of this study.

Salt, B.K.; Carrasquillo, R.L.; Loehr, R.C.; Fowler, D.W.

1995-04-01

20

Application of Abrasive-Waterjets for Machining Fatigue-Critical Aircraft Aluminum Parts  

SciTech Connect

The effects of dry-grid blasting of AWJ-machined dog-bone specimens of aircraft aluminum with aluminum oxide abrasives were investigated in terms of enhancement in fatigue performance and mitigating concerns of abrasive contamination. Results obtained from fatigue tests have indicated that the surface roughness, Ra, of AWJ-induced striations is inversely proportional to the fatigue life. The fatigue life of AWJ-machined and baseline specimens, excluding those processed with dry-grit blasting, decreases with the increase in Ra. Removal of the striations with dry-grit blasting until they disappear visually only reduces Ra from 3.5 to 2.4 ?m and is still higher than that of the conventionally machined edges with Ra = 1.6 ?m. From the surface roughness point of view, the fatigue life of the dry-grit blasted specimens should not have exceeded that of the baseline counterparts. Yet the dry-grit blasting process has extended the fatigue life of the AWJ-machined specimens and the baseline counterparts by more than four and three times, respectively. The extraordinary boost in the fatigue performance is believed to be attributed to the induction of residual compressive stresses by dry-grit blasting. Such a belief was subsequent confirmed quantitatively through measurements of residual compressive stresses. Dry-grid blasting can be carried out efficiently and cost effectively by stacking AWJ-machined parts together. The benefits gained from dry-grit blasting simply outweigh the marginal cost increase.

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

2010-08-19

21

Surface treatment of wire electro-discharge machined engineering ceramics by abrasive blasting  

Microsoft Academic Search

The surface integrity of electro-discharge machined engineering ceramics and their surface modification by abrasive blasting have been investigated in this study. Flexural strength was used for evaluating the effect of the two machining processes on the surface of machined specimens. The distributions of strength data were further analyzed by the Weibull statistical method to give a quantitative measure of the

T. C. Lee; J. H. Zhang

1998-01-01

22

Effects of Grit Blasting and Annealing on the High-Temperature Oxidation Behavior of Austenitic and Ferritic Fe-Cr Alloys  

NASA Astrophysics Data System (ADS)

Grit blasting (corundum) of an austenitic AISI 304 stainless steel (18Cr-8Ni) and of a low-alloy SA213 T22 ferritic steel (2.25Cr-1Mo) followed by annealing in argon resulted in enhanced outward diffusion of Cr, Mn, and Fe. Whereas 3 bar of blasting pressure allowed to grow more Cr2O3 and Mn x Cr3- x O4 spinel-rich scales, higher pressures gave rise to Fe2O3-enriched layers and were therefore disregarded. The effect of annealing pre-oxidation treatment on the isothermal oxidation resistance was subsequently evaluated for 48 h for both steels and the results were compared with their polished counterparts. The change of oxidation kinetics of the pre-oxidized 18Cr-8Ni samples at 850 °C was ascribed to the growth of a duplex Cr2O3/Mn x Cr3- x O4 scale that remained adherent to the substrate. Such a positive effect was less marked when considering the oxidation kinetics of the 2.25Cr-1Mo steel but a more compact and thinner Fe x Cr3- x O4 subscale grew at 650 °C compared to that of the polished samples. It appeared that the beneficial effect is very sensitive to the experimental blasting conditions. The input of Raman micro-spectroscopy was shown to be of ground importance in the precise identification of multiple oxide phases grown under the different conditions investigated in this study.

Proy, M.; Utrilla, M. V.; Otero, E.; Bouchaud, B.; Pedraza, F.

2014-08-01

23

Fibrogenicity and carcinogenic potential of smelter slags used as abrasive blasting substitutes  

SciTech Connect

This study was designed to examine the fibrogenic and carcinogenic potentials of three smelter slags (primary copper slag, secondary copper slag, and nickel slag) that have been used for a number of years as substitutes for sand in abrasive blasting operations. Seven groups of 85 male Fischer 344 rats (approximately 180 g) were used. Each group was given a single 20-mg dose of one of the following test materials via intratracheal instillation: primary copper slag, secondary copper slag, nickel slag, feldspar, Min-U-Sil, novaculite, or vehicle control. Chemical, particle size, and surface area analyses were performed for each test dust. Animals were weighed monthly, and ten animals per group were necropsied at the 6-, 12-, and 18-mo interim sacrifices. The terminal sacrifice was conducted at 22 mo. Hematoxylin and eosin stained histologic sections were prepared from designated formalin-fixed tissues collected at necropsy and examined microscopically. The pulmonary fibrogenic and carcinogenic potentials of the three smelter slags were compared histopathologically with feldspar, novaculite, Min-U-Sil, and vehicle controls. Only minimal to slight alveolar wall fibrosis was seen in the two copper slag groups, while the response seen with nickel slag was consistent with a foreign body reaction with minimal fibrosis seen in only an occasional animal. The major reaction seen in both the feldspar- and the novaculite-treated rats was a granulomatous inflammation with varying degrees of fibrosis associated with the granulomas. Significant numbers of primary lung tumors, principally adenocarcinomas and adenomas, were seen in the copper slag (p = 0.005 and p = 0.022 for the primary and secondary slags, respectively), in the feldspar (p = 0.007), in the novaculite (p less than 0.001), and in the Min-U-Sil (p less than 0.001) groups when compared to the vehicle control group.

Stettler, L.E.; Proctor, J.E.; Platek, S.F.; Carolan, R.J.; Smith, R.J.; Donaldson, H.M.

1988-01-01

24

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

Microsoft Academic Search

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

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

2012-01-01

25

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

SciTech Connect

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 been considered, and much effort has gone to recycling through decontamination, melting and unconditional release of metals. In a broader context, recycling of materials can considered to be a first order ecological priority in order to limit the quantities of radioactive wastes for final disposal and to reduce the technical and economic problems involved with the management of radioactive wastes. It will help as well to make economic use of primary material and to conserve natural resources of basic material for future generations. In a demonstration programme, Belgoprocess has shown that it is economically interesting to decontaminate metal components to unconditional release levels using dry abrasive blasting techniques, the unit cost for decontamination being only 30 % of the global cost for radioactive waste treatment, conditioning, storage and disposal. As a result, an industrial dry abrasive blasting unit was installed in the Belgoprocess central decontamination infrastructure. At the end of December 2006, more than 1,128 Mg of contaminated metal has been treated as well as 313 Mg of concrete blocks. The paper gives an overview of the experience relating to the decontamination of metal material and concrete blocks at the decommissioning of the Eurochemic reprocessing plant in Dessel, Belgium as well from the decontamination of concrete containers by abrasive blasting. (authors)

Gills, R.; Lewandowski, P.; Ooms, B.; Reusen, N.; Van Laer, W.; Walthery, R. [Belgoprocess N.V., Gravenstraat 73, 2480 Dessel (Belgium)

2007-07-01

26

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

27

Automated Blast Cleaner  

NASA Technical Reports Server (NTRS)

Automatic grit-blasting machine removes melted-layer residue from electrical-discharge-machined surfaces of turbine blades. Automatic control system of machine provides steady flow of grit and maintains blast nozzles at proper distance and in correct orientation perpendicular to surface being blasted, regardless of contour. Eliminates localized excessive blasting and consequent excessive removal of underlying material, blasting of adjacent surfaces, and missed areas.

Pickett, Isaiah R.; Yulfo, Alyce R.

1992-01-01

28

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

29

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

30

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

31

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 ...

32

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

33

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

34

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

35

High-efficiency mirror finishing characteristics of ceramics with extremely fine grit diamond wheels  

SciTech Connect

In order to solve the problems of the loose abrasive method, such as low fishing efficiency, etc., a new vertical type ultra-precision plane honing machine using an extremely fine grit diamond wheel was developed by the authors for mirror finishing of hard and brittle materials including ceramics as a bonded abrasive method. Using this machine, the high-efficiency mirror finishing of ceramics was carried out successfully. In this paper, the theoretical model and formulas of plane honing are presented along with the results of a few experiments for examining the high-efficiency mirror finishing characteristics of ceramics using extremely fine grit diamond wheels.

Wang, Xu-Jin [SpeedFam Co., Ltd., Kanagawa (Japan); Syoji, Katsuo; Kuriyagawa, Tsunemoto [Tohoku Univ., Sendai (Japan)

1996-12-31

36

Solidification\\/stabilization of spent abrasives and use as nonstructural concrete  

Microsoft Academic Search

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

D. J. Brabrand; R. C. Loehr

1993-01-01

37

Abrasive Wear Study of NiCrFeSiB Flame Sprayed Coating  

NASA Astrophysics Data System (ADS)

In the present study, abrasive wear behavior of NiCrFeSiB alloy coating on carbon steel was investigated. The NiCrFeSiB coating powder was deposited by flame spraying process. The microstructure, porosity and hardness of the coatings were evaluated. Elemental mapping was carried out in order to study the distribution of various elements in the coating. The abrasive wear behavior of these coatings was investigated under three normal loads (5, 10 and 15 N) and two abrasive grit sizes (120 and 320 grit). The abrasive wear rate was found to increase with the increase of load and abrasive size. The abrasive wear resistance of coating was found to be 2-3 times as compared to the substrate. Analysis of the scanning electron microscope images revealed cutting and plowing as the material removal mechanisms in these coatings under abrasive wear conditions used in this investigation.

Sharma, Satpal

2013-10-01

38

Abrasive tip treatment for use on compressor blades  

NASA Technical Reports Server (NTRS)

A co-spray process was used which simultaneously but separately introduces abrasive grits and metal matrix powder into the plasma stream and entraps the abrasive grits within a molten matrix to form an abrasive coating as the matrix material solidifies on test specimen surfaces. Spray trials were conducted to optimize spray parameter settings for the various matrix/grit combinations before actual spraying of the test specimens. Rub, erosion, and bond adhesion tests were conducted on the coated specimens in the as-sprayed condition as well as on coated specimens that were aged for 100 hours at a temperature of 866K (1100 F). Microscopic examinations were performed to determine the coating abrasive-particle content, the size and shape of the adhesive particles in the coating, and the extent of compositional or morphological changes resulting from the aging process. A nickel chromium/aluminum composite with No. 150 size (0.002 to 0.005 inch) silicon carbide grits was selected as the best matrix/abrasive combination of the candidates surveyed for coating compressor blade tips.

Pedersen, H. C.

1984-01-01

39

Characteristics of grit in Canada goose gizzards  

Microsoft Academic Search

In many localities, Canada geese (Branta canadensis) have habituated to urban settings and their populations are increasing. Reproductive inhibitors contained in synthetic grit could play a role in integrated Canada goose management. We describe and quantity the physical characteristics of natural grit collected from the gizzards of Canada geese from 4 regions of the United States. The average grit sample

Kurt C. VerCauteren; Michael J. Lavelle; Kirk J. Shively

2003-01-01

40

Potential of Air-Propelled Abrasives for Selective Weed Control  

Technology Transfer Automated Retrieval System (TEKTRAN)

Novel forms of selective weed control are needed by many types of growers, but especially organic growers who are restricted from using synthetic herbicides. Abrasive grit made from corn cobs was expelled from a sand blaster at 517 kPa pressure and aimed at seedlings of common lambsquarters and corn...

41

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

Microsoft Academic Search

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

S. C. Tjong; K. C. Lau

2000-01-01

42

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

43

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 (5-168,090 mg kg(-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

44

Development of a two-body wet abrasion test method with attention to the effects of reused abradant  

SciTech Connect

Abrasive wear is among the most common and costliest causes for material wastage, and it occurs in many forms. A simple method has been developed to quantify the response of metals and alloys to two-body wet abrasion. A metallographic polishing machine was modified to create a disk-on-flat sliding test rig. Adhesive-backed SiC grinding papers were used under fixed load and speed to rank the abrasive wear of seven alloy steels, some of which are candidates for drill cones for geothermal drilling. Standardized two-body abrasion tests, like those described in ASTM G132, feed unused abrasive into the contact; however, the current work investigated whether useful rankings could still be obtained with a simpler testing configuration in which specimens repeatedly slide on the same wear path under water-lubricated conditions. Tests using abrasive grit sizes of 120 and 180 resulted in the same relative ranking of the alloys although the coarser grit produced more total wear. Wear decreased when the same abrasive disk was re-used for up to five runs, but the relative rankings of the steels remained the same. This procedure was presented to ASTM Committee G2 on Wear and Erosion as a potential standard test for wet two-body abrasive wear.

Blau, Peter Julian [ORNL; Dehoff, Ryan R [ORNL

2012-01-01

45

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

46

Processing of edible peanut flour and grits  

Microsoft Academic Search

Edible peanut flour and grits have been produced by a commercial prepress solvent extraction method. The finished flour exhibits\\u000a excellent extrusion-expansion characteristics for use in both cereal and snack food items. Soluble carbohydrate profile indicates\\u000a peanut flour is lower in raffinose and stachyose than commercial soy flour. The bland flavor and light tan color facilitates\\u000a incorporation of peanut flour and

J. L. Ayres; L. L. Branscomb; G. M. Rogers

1974-01-01

47

Contamination of titanium castings by aluminium oxide blasting  

Microsoft Academic Search

Objectives: It is desirable that the surfaces of surgical implants be uncontaminated by foreign materials to avoid untoward tissue reactions, and grit blasting is widely assumed to leave clean metal surfaces. SEM examination and X-ray microanalysis of a recovered ‘pure’ titanium implant casting that was associated with tissue breakdown revealed embedded particles of alumina. The casting had been cleaned of

B. W. Darvell; N. Samman; W. K. Luk; R. K. F. Clark; H. Tideman

1995-01-01

48

Refurbishment of SRB aluminum components by walnut hull blast removal of protective coatings  

NASA Technical Reports Server (NTRS)

A test program was conducted to develop, optimize, and scale up an abrasive blasting procedure was developed for refurbishment of specific SRB components: aft skirt, forward skirt, frustrum, and painted piece parts. Test specimens utilizing 2219 T87 aluminum substrate of varying thicknesses were prepared and blasted at progressively increasing pressures with selected abrasives. Specimens were analyzed for material response. The optimum blasting parameters were determined on panel specimens and verified on a large cylindrical integrated test bed.

Colberg, W. R.; Gordon, G. H.; Jackson, C. H.

1982-01-01

49

Abrasive wear in multiphase microstructures  

Microsoft Academic Search

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

T. H. Kosel; N. F. Fiore

1981-01-01

50

Computational studies of polyurea coated steel plate under blast loads  

E-print Network

· High Abrasion resistance Source: PCI, http://www.pcimag.com/CDA/Archives/779f754db76a7010VgnVCM100000f Research (ONR N00014-05-1-0844) #12;Background · Lightweight material is sought for blast resistant coatings increase blast resistance of existing and temporary structures, Porter et al., AFRL #12;Motives

51

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

SciTech Connect

Laboratory tests were conducted to determine the fatigue performance of 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 not only confirmed the findings of the aluminum dog-bone specimens but also further enhance the fatigue performance. In addition, titanium is known to be notoriously difficult to cut with contact tools while AWJs cut it 34% faster than stainless steel. AWJ cutting and dry-grit blasting are shown to be a preferred combination for processing aircraft titanium that is fatigue critical.

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

2010-10-04

52

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

53

Solidification\\/stabilization of used abrasive media for non-structural concrete using portland cement. Interim research report  

Microsoft Academic Search

Highway bridges in the United States are painted to resist corrosion and to help maintain the structural integrity of the bridge. Periodically, it is necessary to remove the existing paint so that the surface can be repainted. Most often the removal process consists of blasting the surface with an abrasive such as sand or slag. The blast media then contains

M. T. Webster; R. L. Carrasquillo; R. C. Loehr; D. W. Fowler

1994-01-01

54

Application of Abrasive-Waterjets for Machining Fatigue-Critical Aircraft Aluminum Parts  

Microsoft Academic Search

The effects of dry-grid blasting of AWJ-machined dog-bone specimens of aircraft aluminum with aluminum oxide abrasives were investigated in terms of enhancement in fatigue performance and mitigating concerns of abrasive contamination. Results obtained from fatigue tests have indicated that the surface roughness, Ra, of AWJ-induced striations is inversely proportional to the fatigue life. The fatigue life of AWJ-machined and baseline

H. T. Liu; Yuri Hovanski; Michael E. Dahl; J. Zeng

2010-01-01

55

Abrasion resistance of high-strength concrete in hydraulic structures  

Microsoft Academic Search

This paper presents the results of the examinations of abrasive wear of the nine types of high-strength concrete (HSC) with compressive strength of 75÷120MPa. The mixes were made with: Portland cement CEM I 42.5R, CEM I 52.5R and blast-furnace cement CEM IIIA 42.5, basalt aggregate with added superplasticizers and silica fume. The mixes contained of steel fiber: 30 and 50mm

El?bieta Horszczaruk

2005-01-01

56

Blast Injuries  

MedlinePLUS

... DVBIC & TBI Educational Materials Research DVBIC Locations Press Blast Injuries (U.S. Army photo by Sgt. Gustavo Olgiati) ... games. More Information: 04/12/11: Research Examines Blast Impact on Human Brain 04/06/09: Military ...

57

Abrasion resistant heat pipe  

DOEpatents

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

Ernst, Donald M. (Leola, PA)

1984-10-23

58

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

59

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

60

ORIGINAL PAPER Use of grit supplements by waterbirds: an experimental  

E-print Network

with food particles causes Pb poisoning in a large number of waterbirds, this being one of the main causes ingest Pb shot pellets as grit or inadvertently with food particles and thus suffer from Pb poisoning to reduce lead poisoning Monica Martinez-Haro & Andy J. Green & Pelayo Acevedo & Rafael Mateo Received: 17

Paris-Sud XI, Université de

61

ORIGINAL PAPER Use of grit supplements by waterbirds: an experimental  

E-print Network

or inadvertently with food particles and thus suffer from Pb poisoning (Trost 1981; Mateo and Guitart 2000). Lead to reduce lead poisoning Monica Martinez-Haro & Andy J. Green & Pelayo Acevedo & Rafael Mateo Received: 17 The ingestion of spent Pb shot due to confusion with grit or inadvertently with food particles causes Pb

Green, Andy J.

62

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

63

Abrasion and impact resistant coatings  

SciTech Connect

Abrasion and impact resistance are a prime requirement for many materials applications. To best protect plastic of metal-based composites from abrasion and impact, a surface coating that is simultaneously very hard and highly yielding is necessary. Both these requirements can be met by a dense pattern of emergent fibers of high L/D ration, well rooted but with one and free, i.e., hair. A covering of such hair, with fibers long enough to bend over, dense enough for mutual shielding but thin enough to accommodate themselves to impacting objects, will give substantial protection against impact or particle abrasion.

Hirschfeld, T.; Haugen, G.; Steele, W.

1986-06-30

64

Abrasion and impact resistant coatings  

SciTech Connect

Abrasion and impact resistance are a prime requirement for many materials applications. To best protect plastic or metal-based composites from abrasion and impact, a surface coating that is simultaneously very hard and highly yielding is necessary. Both these requirements can be met by a dense pattern of emergent fibers or high L/D ratios, well rooted but with one end free, i.e., hair. A covering of such hair, with fibers long enough to accommodate themselves to impacting objects, will give substantial protection against impact or particle abrasion. 1 tab.

Steele, W.A.; Mohr, P.B.; Leider, H.R.

1987-12-31

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

Resistance to particle abrasion of selected plastics  

Microsoft Academic Search

Accelerated abrasive wear of plastic parts in a piece of production machinery prompted a laboratory study to find a material with better abrasion resistance. The abrasion occurred in a machine that compacted ‘sand-like’ particles of an inorganic compound. The abrasion resistance of a wide variety of plastics and different durometer polyurethanes (21 materials) was tested with a modification of the

Kenneth G. Budinski

1997-01-01

67

Tooth Abrasion and Tooth Erosion  

MedlinePLUS

... problem is called acid reflux. People with the eating disorder bulimia can get tooth erosion because of repeated vomiting. Even the chlorine and other chemicals in a swimming pool can cause erosion over time. Symptoms Toothbrush abrasion causes V- ...

68

Transparent, abrasion resistant coating compositions  

SciTech Connect

There is disclosed transparent, abrasion resistant coating compositions comprising a colloidal dispersion of a water insoluble dispersant in a water-alcohol solution of the partial condensate of silanol wherein the dispersant comprises metals, alloys and salts thereof.

Ashlock, L.T.; Mukamal, H.; White, W.H.

1985-02-19

69

Nuclear Blast  

MedlinePLUS

... more susceptible to blast effects. Existing meteorological conditions. Wind speed and direction will affect arrival time of ... from a nuclear explosion may be carried by wind currents for hundreds of miles if the right ...

70

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

71

Characterizing hydrocyclone performance for grit removal from wastewater treatment activated sludge plants  

Microsoft Academic Search

Typically, 15–45% of the mixed liquor (sludge) in biological wastewater treatment plants (WWTPs) consists of inorganic (fixed) suspended solids. A portion of these inorganic compounds is grit (sand) originating from the influent. Grit accumulation impacts WWTP design and operating costs as these unbiodegradable solids reduce the effective treatment capacity of the bioreactor and other unit operations that must be sized

Majdala Mansour-Geoffrion; Peter L. Dold; Daniel Lamarre; Alain Gadbois; Stéphane Déléris; Yves Comeau

2010-01-01

72

Reduced toxicity of fumonisin B1 in corn grits by single-screw extrusion  

Technology Transfer Automated Retrieval System (TEKTRAN)

Extrusion cooking under conditions of high heat and pressure reduces the concentration of fumonisins in corn-based products; however, the toxicity of heretofore uncharacterized fumonisin reactions products in extruded materials has not been determined. Uncontaminated corn grits, grits spiked with 3...

73

The effect of extrusion on the fumonisin content and toxicity of corn grits  

Technology Transfer Automated Retrieval System (TEKTRAN)

Extrusion cooking reduces fumonisin concentrations in corn; however, the nature and toxicity of fumonisin reaction products in food matrices are not well understood. Corn grits were contaminated by spiking with fumonisin B1 (FB1) (Spiked grits = SG, 43 nmol/g dry wt FB1; measured by LC-MS) or by fer...

74

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

75

Materials resist wet coal abrasion  

SciTech Connect

The use of wear-resistant lining materials in coal preparation and coal handling plants to reduce the abrasion caused by wet coal is discussed. Various types of material such as ceramics, polyethylene, polyurethane and epoxies are considered and the ways in which they may be applied are described.

Green, P.

1983-01-01

76

Distribution of lead in urban roadway grit and its association with elevated steel structures.  

PubMed

In an effort to determine the source of exterior lead contamination, we investigated the concentration of lead in roadway grit along major thoroughfares in New York City and in certain areas under elevated steel structures supporting elevated rails. Such structures represent only one source of lead in roadway grit. While data revealed that the median lead concentration in roadway grit did not exceed the standard for a lead hazard in bare residential soil in any borough, the limit of 400 microg/g was exceeded 22%, 18%, 10.5%, and 7.7% of the time in Manhattan, Brooklyn, The Bronx, and Queens, respectively. The second part of the study revealed the presence of high concentrations of lead in roadway grit directly under elevated steel structures. The differences in the concentration of lead in roadway grit under steel structures in comparison to areas in NYC not near elevated rails was statistically significant. Of the eight sites studied from 225 total samples, the median roadway grit lead level was 340 ppm, while the level under steel structures was 1480 ppm. Preliminary efforts to determine particle size distribution revealed that 84% of the particles were in the range of 125-500 microm, but the highest concentration of lead was in the smallest fraction analyzed (<63 microm). Lead contamination of roadway grit from restoration of elevated painted steel structures is a public health problem as these lead particulates get re-suspended in the ambient environment and are wafted and tracked into residences. PMID:16793117

Weiss, Arlene L; Caravanos, Jack; Blaise, Marc J; Jaeger, Rudolph J

2006-12-01

77

Rheological quality of pearl millet porridge as affected by grits size.  

PubMed

Study was conducted to optimize pearl millet grits size for the preparation of acceptable porridge with skimmed milk powder (SMP). Pearl millet porridge was prepared with different grits size (1.410, 0.841, 0.595, and 0.420 mm). A positive (r?=?0.904) correlation was observed between water absorption index and grits size. Porridge showed shear thinning behavior as, initially shear stress increased with increase in shear rate and later on decreased. Porridge prepared with larger grits (1.410 mm) exhibited higher firmness (38.4?±?1.27 N) and viscosity (446?±?3.9 cP), whereas smaller grits (0.420 mm) resulted in less viscous (118.8?±?1.74 cP) and firm (20.4?±?1.85 N) porridge. The medium grits (0.841 mm) produced porridge with acceptable firmness (30.7?±?1.56 N) and viscosity (298.1?±?8.81 cP) with moderate (6.0?±?0.10) acceptability. To improve sensory quality of porridge (grits size 0.841 mm); skimmed milk powder at different levels (0, 5, 10 and 15 %) was added and its effect on various quality parameters was studied. SMP addition significantly (P???0.05) modified the gelatinization and gelling behavior of grits and decreased (P???0.05) all the pasting characteristics except pasting temperature, which increased from 77.1?±?1.85 to 85.9?±?3.46 °C. The peak (499?±?6.6 cP) and final viscosity (450?±?11.9 cP) of porridge (0.841 mm) prepared with 15 % SMP are quite similar. Hence, it maintains viscosity on cooling, similar to maximum viscosity attained during cooking. Keeping in view the rheological, firmness and sensory quality, 0.841 mm grits of pearl millet with 15 % SMP was found optimum for preparation of acceptable porridge. PMID:25190879

Yadav, Deep N; Chhikara, Navnidhi; Anand, Tanupriya; Sharma, Monika; Singh, Ashish K

2014-09-01

78

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

79

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

80

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

81

Grit ingestion as a source of metal exposure in the spruce grouse, Dendragapus canadensis.  

PubMed

The objective of this study was to determine if ingestion of grit was a source of metal exposure to the spruce grouse, Dendragapus canadensis. A secondary objective was to assess whether grit could provide a supplemental source of essential minerals to their diet. Ca, P, Mg, S, Zn, Cu, Ni, Co, Cr, Fe, Mn, Al, Pb and Cd of liver (adult, yearling, chicks), crop and gizzard contents (adults) were determined for grouse collected from a relatively pristine boreal forest region of north-central Ontario, Canada. With the exception of Cd liver, concentrations were independent of age [one-way analysis of variance (ANOVA); p>0.004). Zn liver concentrations tended to be greater in adults than yearlings and chicks (one-way ANOVA; p=0.02). Liver concentrations of Cd increased with age (r=0.99; p<0.001). The contribution of crop items to total gizzard elemental content was element specific; crop contents contributed 90-100% of Mn and Zn, 70% for P and Ca, 60% for Pb, 50% for S, and 0-25% for Cu, Mg, Ni, Al, Fe, Co, Cr and Cd to the total elemental concentration of gizzard contents (crop plus grit). Incorporation of grit by grouse could, therefore, constitute an important source of essential macro-(Ca, P, Mg, S) and trace elements (Cu, Fe) but not for Mn or Zn. However, in addition to providing nutrients to the bird, ingestion of grit results in exposure to toxic trace metals such as Cd which in turn is accumulating in the liver. Research directed at determining grit turnover time, and hence metal exposure rates, in bird species which ingest grit to aid in food digestion is required. The toxicological significance of Cd exposure to grit-ingesting birds needs attention. PMID:15093036

Bendell-Young, L I; Bendell, J F

1999-09-01

82

Abrasive wear of high speed steels: Influence of abrasive particles and primary carbides on wear resistance  

Microsoft Academic Search

A ball cratering test has been used to investigate the abrasive wear of high speed steels with different volume fraction and size of primary carbides. Three different abrasives, SiC, Al2O3 and ZrO2 were used. Wear mechanisms were investigated by scanning electron microscopy (SEM). A good correlation between the hardness of the abrasives and the abrasive wear coefficient was found. Higher

E. Badisch; C. Mitterer

2003-01-01

83

18—THE ABRASION-RESISTANCE OF SOME WOVEN FABRICS AS DETERMINED BY THE ACCELEROTOR ABRASION TESTER  

Microsoft Academic Search

The use of an Accelerotor abrasion tester is discussed, and the abrasion-resistance of several plain-weave fabrics is shown to depend on the type of fibre. The materials are ranked in order of decreasing resistance to abrasion with carborundum, rubber, metal, and plastics abradants. Polyamide fibres have outstanding resistance and cellulose-ester and regenerated protein fibres poor resistance to abrasion. The order

H. M. Elder; A. S. Ferguson

1969-01-01

84

Abrasion-resistant coatings for plastic surfaces  

NASA Technical Reports Server (NTRS)

Optically clear composition of organosilicon compounds insulates plastic surfaces and protects them from abrasion. Plasma polymerization process produces superior uniformity and clarity than previous coating techniques.

Wydeven, T.; Hollahan, J. R.

1976-01-01

85

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

86

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

87

Surface evolution models in abrasive jet micromachining  

Microsoft Academic Search

The paper presents model predictions and experimental data related to the abrasive jet micromachining of masked and unmasked channels in glass. The spatial and velocity distributions of particles in the jet of an abrasive jet micromachining (AJM) setup were measured using a novel technique. It was found that the velocity decreased linearly from the centerline of the jet to the

A. Ghobeity; T. Krajac; T. Burzynski; M. Papini; J. K. Spelt

2008-01-01

88

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

89

Ceramic-bonded abrasive grinding tools  

DOEpatents

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

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

1994-11-22

90

Corneal abrasions associated with pepper spray exposure.  

PubMed

Pepper spray containing oleoresin capsicum is used by law enforcement and the public as a form of nonlethal deterrent. Stimulated by the identification of a case of a corneal abrasion associated with pepper spray exposure, a descriptive retrospective review of a physician-maintained log of patients presenting to a jail ward emergency area over a 3-year period was performed. The objective was to give some quantification to the frequency with which an emergency physician could expect to see corneal abrasions associated with pepper spray exposure. Of 100 cases of pepper spray exposure identified, seven patients had sustained corneal abrasions. We conclude that corneal abrasions are not rare events when patients are exposed to pepper spray and that fluorescein staining and slit lamp or Wood's lamp examination should be performed on all exposed patients in whom corneal abrasions cannot be excluded on clinical grounds. PMID:10830682

Brown, L; Takeuchi, D; Challoner, K

2000-05-01

91

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

92

The abrasion and impact-abrasion behavior of austempered ductile irons  

SciTech Connect

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

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

1998-01-01

93

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

94

Grit and perseverance in suicidal behavior and non-suicidal self-injury.  

PubMed

Data indicate persistence facilitates suicidal behavior. Non-suicidal self-injury (NSSI) is characterized by difficulty persisting while upset. The relationship between NSSI and suicidal behavior thus may hinge upon persistence. Participants were 604 undergraduates (79.5% women; 42.4% African American; 6.1% with 1 + prior suicide attempt). Data were collected online via self-report and analyzed using hierarchical multiple regression. As expected, higher levels of grit and perseverance predicted more frequent suicide attempts. Furthermore, grit and perseverance moderated the relationship between NSSI and suicide attempts, which increased in magnitude as individuals reported greater persistence. Findings depict suicidal behavior as a deliberate pursuit of death. PMID:25611458

Anestis, Michael D; Selby, Edward A

2015-04-01

95

Abrasion and resistant discharge valve developed  

NASA Technical Reports Server (NTRS)

Discharge valve capable of withstanding intense radiation and high abrasion was developed for use in a fluidized bed reactor. The valve which employs a replaceable Teflon seal, has only one moving part and is designed for remote assembly and disassembly.

Gottwald, W. L.

1969-01-01

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

[The application of air abrasion in dentistry].  

PubMed

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

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

2014-01-01

98

Solidification/stabilization of used abrasive media for non-structural concrete using portland cement. Interim research report  

SciTech Connect

Highway bridges in the United States are painted to resist corrosion and to help maintain the structural integrity of the bridge. Periodically, it is necessary to remove the existing paint so that the surface can be repainted. Most often the removal process consists of blasting the surface with an abrasive such as sand or slag. The blast media then contains elements present in the paint, such as cadmium, chromium and lead. The spent media may be a hazardous waste as defined by EPA`s Toxicity Characteristic (TC) criterion. This criterion uses the Toxicity Characteristic Leaching Procedure (TCLP) to determine whether a waste is classified as a hazardous waste. This procedure subjects the waste to a highly acidic environment in which chemicals can leach out of the waste. The leachate enviornment is then analyzed to determine the concentration of chemical leached, which must fall within the TC criterion. Some spent blasting material has been shown to have TCLP metal concentrations exceeding the TC criterion. The Texas Department of Transportation (TxDOT) has begun to recycle spent abrasive media in portland cement-based concrete using solidification/stabilization (S/S) techniques. This technology is designed to immobilize the metals while recycling the spent abrasive media as a component in non-structural concrete. The study has revealed the effectiveness of portland cement-based S/S systems in recycling contaminated spent abrasive media in portland cement-based concrete. The long-term leaching behavior of metals from these concrete products was examined using sequential extraction leaching tests.

Webster, M.T.; Carrasquillo, R.L.; Loehr, R.C.; Fowler, D.W.

1994-11-01

99

The steady state abrasion of rubber: Why are the weakest rubber compounds so good in abrasion?  

Microsoft Academic Search

This paper examines the blade abrasion of four different rubber materials, unfilled natural rubber (NR), unfilled styrene butadiene rubber (SBR), unfilled butadiene rubber (BR) and carbon black filled styrene butadiene rubber. Each is abraded until the steady state abrasion pattern is developed on the surface of moulded rubber wheels. The steady state conditions are measured using the weight loss per

H. Liang; Y. Fukahori; A. G. Thomas; J. J. C. Busfield

2010-01-01

100

Effect of abrasive mineral on alloy performance in the ball mill abrasion test  

Microsoft Academic Search

The ball mill abrasion test (BMAT) promises to offer accurate prediction of relative service lives of wear-resistant alloys for liners and grinding media in mineral grinding environments. Relative alloy performance depends strongly on the abrasive minerals present. Towards a greater understanding of factors controlling relative performance, BMAT data have been generated using several pure and blended minerals. The results show

J. D. Gates; M. S. Dargusch; J. J. Walsh; S. L. Field; M. J.-P. Hermand; B. G. Delaup; J. R. Saad

2008-01-01

101

Chemical and toxicological evaluation of fumonisin B1 in extruded corn grits.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Extrusion cooking reduces fumonisin concentrations in corn but its effect on fumonisin toxicity is unknown. Batches of corn grits were contaminated by spiking with fumonisin B1 (FB1) (SG, 43 ppm) or by fermentation (FG1, 46 ppm FB1; FG2 48 ppm FB1) and then extruded with and without the addition of ...

102

Extrusion cooking using a twin-screw apparatus reduces toxicity of fumonisin-contaminated corn grits  

Technology Transfer Automated Retrieval System (TEKTRAN)

Extrusion cooking using a single screw configuration reduced fumonisin concentrations of corn grits in an earlier study. Adding glucose before cooking enhanced reductions and, in one of three trials, partially reversed in vivo toxicity. To determine the effectiveness of extrusion using the more effi...

103

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

E-print Network

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

104

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 Department of Ecology and Evolutionary Biology, Brown University, Providence, Rhode Island 02912, USA c amongst many herbivorous clades from a browsing diet of leaves to a grazing diet of grasses

Benton, Michael

105

Software-Defined Cyber-Physical Multinetworks Zhijing Qin, Ngoc Do, Grit Denker, Nalini Venkatasubramanian  

E-print Network

and inputs in a structured manner to generate situational awareness.. In particular, we discuss the role, securely, efficiently and in real-time. CPS technologies can be used to create situation-aware [1Software-Defined Cyber-Physical Multinetworks Zhijing Qin, Ngoc Do, Grit Denker, Nalini

Venkatasubramanian, Nalini

106

Chemical and Toxicological Fate of Fumonisin B1 during Extrusion Processing of Corn Grits  

Technology Transfer Automated Retrieval System (TEKTRAN)

Two batches of flaking corn grits were prepared by growing Fusarium verticillioides to contain low and high levels of fumonisin B1 (FB1), Batch-1 at 9.7 ppm and Batch-2 at 50 ppm FB1 as determined by HPLC. These two batches were extruded (Batch-1E; Batch-2E) or extruded with 10% w/w glucose supplem...

107

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.

108

Hardfacing and wear plates battle abrasion  

SciTech Connect

This article examines abrasion-resistant steels and hardfacing as two effective weapons at the disposal of material handlers. It points out that abrasion is probably the single most destructive form of wear in the mixing and processing of coal. Particulate matter such as quartz sand and other minerals including coal curtail in-service life of dragline buckets, chute, crusher rolls, gates and valves, exhauster fan blades, target plates, truck beds, hoppers, vibrating pans, grinding mills, piping elbows, etc. The advantages of abrasion-resistant steels and hardfacing can be obtained in the form of a composite wear plate-hardfacing on a carbon steel backup plate. It concludes that the composite wear plate represents a major innovation since its advantages include ease of handling, low cost and easy installation, minimum on-site welding time and versatility. Its use is limited only to the consumer's creativity in application.

Miller, R.F.

1983-06-01

109

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

110

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

111

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

112

21 CFR 872.6010 - Abrasive device and accessories.  

Code of Federal Regulations, 2012 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,...

2012-04-01

113

29 CFR 1910.215 - Abrasive wheel machinery.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Abrasive wheel machinery. 1910.215 Section 1910.215...OCCUPATIONAL SAFETY AND HEALTH STANDARDS Machinery and Machine Guarding § 1910.215 Abrasive wheel machinery. (a) General requirements...

2012-07-01

114

29 CFR 1910.215 - Abrasive wheel machinery.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Abrasive wheel machinery. 1910.215 Section 1910.215...OCCUPATIONAL SAFETY AND HEALTH STANDARDS Machinery and Machine Guarding § 1910.215 Abrasive wheel machinery. (a) General requirements...

2013-07-01

115

29 CFR 1910.215 - Abrasive wheel machinery.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Abrasive wheel machinery. 1910.215 Section 1910.215...OCCUPATIONAL SAFETY AND HEALTH STANDARDS Machinery and Machine Guarding § 1910.215 Abrasive wheel machinery. (a) General requirements...

2011-07-01

116

29 CFR 1910.215 - Abrasive wheel machinery.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Abrasive wheel machinery. 1910.215 Section 1910.215...OCCUPATIONAL SAFETY AND HEALTH STANDARDS Machinery and Machine Guarding § 1910.215 Abrasive wheel machinery. (a) General requirements...

2010-07-01

117

29 CFR 1910.215 - Abrasive wheel machinery.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 false Abrasive wheel machinery. 1910.215 Section 1910.215...OCCUPATIONAL SAFETY AND HEALTH STANDARDS Machinery and Machine Guarding § 1910.215 Abrasive wheel machinery. (a) General requirements...

2014-07-01

118

21 CFR 872.6010 - Abrasive device and accessories.  

Code of Federal Regulations, 2011 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,...

2011-04-01

119

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

120

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

SciTech Connect

Paint removal from military aircraft is often done by plastic media blasting (PMB): the use of plastic grit in a conventional blast jet. However, there is some concern that PMB will cause damage. To help in evaluating this possibility, a time of flight'' meter is used to measure particle velocity in the jet, as a function of air pressure, distance from the nozzle, and particle feed rate, F. Using the data and a momentum balance, a semi-empirical model relating these variables is developed and used for analysis of the effect of F on the intensity of kinetic energy delivery, E, to a work piece. The analysis shows that F has several important effects on E. These methods and results will be useful for damage studies and in production work.

McIntosh, M.J. (Argonne National Lab., IL (United States). Energy Systems Division)

1992-11-01

121

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...

122

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

123

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

124

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

125

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

126

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

127

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

128

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

SciTech Connect

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

Kroll, Peter; Kane, Sally Minch [eds.

1982-04-01

129

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

130

Robotic Water Blast Cleaner  

NASA Technical Reports Server (NTRS)

Water blasting system under development removes hard, dense, extraneous material from surfaces. High pressure pump forces water at supersonic speed through nozzle manipulated by robot. Impact of water blasts away unwanted material from workpiece rotated on air bearing turntable. Designed for removing thermal-protection material, system is adaptable to such industrial processes as cleaning iron or steel castings.

Sharpe, M. H.; Roberts, M. L.; Hill, W. E.; Jackson, C. H.

1983-01-01

131

Technological Advances in Fine Abrasive Processes  

Microsoft Academic Search

Fine abrasives, be they loose or fixed, are invariably used in the production of components of the highest quality in terms of form and finish accuracy, and surface integrity. While optical, mechanical, and electronic applications of advanced ceramics, glasses, and semiconductors may require high form and finish accuracies (e.g., roughnesses in the angstrom range), the depth and nature of the

R. Komanduri; D. A. Lucca; Y. Tani

1997-01-01

132

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

133

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

PubMed Central

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

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

2013-01-01

134

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

135

Abrasion-Resistant Technology and its Prospect for CFB Boilers  

NASA Astrophysics Data System (ADS)

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

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

136

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

137

Abrasion resistance of linings in filament wound composite pipe  

SciTech Connect

Fiberglass filament wound composite pipe has numerous industrial applications including transportation of petroleum and natural gas. Its corrosion resistance is well known but it can be susceptible to abrasion and erosion when it is used to transport slurries or dry gas containing sand particles. However, composite pipe can be manufactured integrally with abrasion resistant linings which protect the pipe from abrasion and erosion and increase its life. Laboratory investigations were performed to determine the effect of abrasive flows through polyurea-lined and unlined glass-reinforced epoxy (GRE) pipe, ultra-high molecular weight (UHMW) polyethylene (PE) pipe, and unlined steel pipe. Results are provided for the abrasion resistance, chemical resistance, adhesion strength, elongation, tensile strength, impact resistance and hardness of selected linings. The abrasion resistance of polyurea-lined composite pipe proved to be almost as resistant to abrasion and erosion as unlined steel pipe without the electrochemical corrosion associated with steel pipe.

Hall, S.C.

1999-07-01

138

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

139

Loose abrasive slurries for optical glass lapping  

SciTech Connect

Loose abrasive lapping is widely used to prepare optical glass before its final polishing. We carried out a comparison of 20 different slurries from four different vendors. Slurry particle sizes and morphologies were measured. Fused silica samples were lapped with these different slurries on a single side polishing machine and characterized in terms of surface roughness and depth of subsurface damage (SSD). Effects of load, rotation speed, and slurry concentration during lapping on roughness, material removal rate, and SSD were investigated.

Neauport, Jerome; Destribats, Julie; Maunier, Cedric; Ambard, Chrystel; Cormont, Philippe; Pintault, B.; Rondeau, Olivier

2010-10-20

140

Manufacture of abrasion-resistant coke  

SciTech Connect

Bodies are press-molded from a mixture of particulate fuel and a binder. These bodies are heated to a temperature between about 600*-900* C in a rotary furnace to degas them. The degassing is carried out without subjecting the bodies to mechanical stresses and without permitting combustion of the expelled volatile gases. The resulting shaped coke has a greatly improved abrasion resistance.

Degel, J.; Giessler, K.; Juntgen, H.; Knoblauch, K.; Zundorf, D.

1980-11-11

141

Dentin abrasion (RDA), enamel abrasion (REA) and polishing scores of dentifrices sold in Switzerland.  

PubMed

Assessments of the abrasion of hard dental tissues produced by different dentifrices are usually carried out on extracted teeth in the laboratory. The tests most commonly used to measure dentifrice abrasion on dentin and enamel are the radiotracer (radio-active) and profilometry methods. The radiotracer dentin (RDA) and enamel (REA) abrasion scores of the 32 dentifrices were determined using the ADA specifications. RDA and REA scores are related to a standard abrasive, calcium pyrophosphate (Ca2P2O7), which is assigned a score of 100 for the RDA method and 10 for the REA method. The same abrasive was used as the standard in the enamel polish study and assigned a score of 100. The RDA scores of the dentifrices tested varied from 37 to 203, the REA scores from 1.0 to 11.7, and the polishing scores ranged from 19.63 to 96.88. Half the dentifrices tested had RDA scores below 100. PMID:2749221

Barbakow, F; Imfeld, T; Lutz, F; Stookey, G; Schemehorn, B

1989-01-01

142

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

143

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

144

Predicting abrasive wear with coupled Lagrangian methods  

NASA Astrophysics Data System (ADS)

In this paper, a mesh-less approach for the simulation of a fluid with particle loading and the prediction of abrasive wear is presented. We are using the smoothed particle hydrodynamics (SPH) method for modeling the fluid and the discrete element method (DEM) for the solid particles, which represent the loading of the fluid. These Lagrangian methods are used to describe heavily sloshing fluids with their free surfaces as well as the interface between the fluid and the solid particles accurately. A Reynolds-averaged Navier-Stokes equations model is applied for handling turbulences. We are predicting abrasive wear on the boundary geometry with two different wear models taking cutting and deformation mechanisms into account. The boundary geometry is discretized with special DEM particles. In doing so, it is possible to use the same particle type for both the calculation of the boundary conditions for the SPH method as well as the DEM and for predicting the abrasive wear. After a brief introduction to the SPH method and the DEM, the handling of the boundary and the coupling of the fluid and the solid particles are discussed. Then, the applied wear models are presented and the simulation scenarios are described. The first numerical experiment is the simulation of a fluid with loading which is sloshing inside a tank. The second numerical experiment is the simulation of the impact of a free jet with loading to a simplified pelton bucket. We are especially investigating the wear patterns inside the tank and the bucket.

Beck, Florian; Eberhard, Peter

2015-02-01

145

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

146

Ceramic Surface Treatment and Abrasion Resistance: An Experimental Study  

Microsoft Academic Search

This study explores experimentally the relationship between pottery surface treatments (texture, slip\\/polish, resin, smooth, and smudge) and abrasion resistance. The surface treatments were applied to low-fired ceramic spheres and then abrasion resistance was measured by weight loss as the specimens were abraded in lapidary tumblers. In terms of total weight loss, slip\\/polished and textured spheres had the poorest abrasion resistance

James M. Skibo; Tamara C. Butts; Michael Brian Schiffer

1997-01-01

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

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

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 dollars and sense of selecting abrasion-resistant materials  

SciTech Connect

Sliding abrasion and impact damage affect mine and plant operating costs on a month-to-month, or, in some cases, day-to-day basis. Modern technology has given us the tools necessary to fight abrasion on every front - materials and techniques that are cost-effective, long-lasting, and easy to use. An inspection of abrasion-resistant materials and processes - metals; ceramics; sprayable and trowelable compounds; polyethylene; urethane; rubber; epoxy - may well provide information that could help improve your company's balance sheet. The following is a compilation of product releases, literature, and manuals offered by manufacturers of abrasion-resistant materials.

Jackson, D.

1988-05-01

151

Curved characteristics behind blast waves.  

NASA Technical Reports Server (NTRS)

The behavior of nonisentropic flow behind a propagating blast wave is theoretically studied. Exact solutions, expressed in closed form in terms of elementary functions, are presented for three sets of curved characteristicseind a self-similar, strong blast wave.

Laporte, O.; Chang, T. S.

1972-01-01

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

Abrasion-Resistant Coating for Flexible Insulation  

NASA Technical Reports Server (NTRS)

Ceramic coating increases durability and heat resistance of flexible high-temperature insulation. Coating compatible with quartz-fabric insulation allowing it to remain flexible during and after repeated exposures to temperatures of 1,800 degree F (982 degree C). Prevents fabric from becoming brittle while increasing resistance to aerodynamic abrasion and loading. Coating consists of penetrating precoat and topcoat. Major ingredients high-purity colloidal silica binder and ground silica filler, which ensure stability and compatibility with fabric at high temperatures. Both precoat and topcoat cured at room temperature.

Mui, D.; Headding, R. E.

1986-01-01

154

Abrasion technology for electric submergible pumps  

SciTech Connect

This paper describes the results of a five-year investigation of sand abrasion phenomena in conventional electrical submergible pumps (ESP). The investigation includes a review of the available literature on two body and three body wear processes in the presence of corrosive fluids, and the development of laboratory test methods from which baseline wear rates for conventional pumps can be established. These baseline wear rates are compared with performance data on pumps incorporating special wear resistant features. Preliminary field test results are also presented.

King, D.G.; Stewart, R.E.; Traylor, F.T.

1983-10-01

155

Abrasion and impact resistant coatings. Quarterly report  

SciTech Connect

We have proven that a layer of reinforcing filaments emerging out of the surface of a composite provides it with substantial protection from abrasion and impact. We have determined the geometrical constraints on fiber diameter, length, root depths, orientation, and packing density required for this protection. Substantial performance has been demonstrated for even incompletely optimized systems. We are in the process of extending this technology to first aluminum and then steel structural metal protection. Pretreatment and assembly methods for such materials have been developed, including at least one suitable for a mass production environment.

Hirschfeld, T.

1985-08-01

156

Abrasive water-jet controlled depth milling of Ti6Al4V alloy – an investigation of the role of jet–workpiece traverse speed and abrasive grit size on the characteristics of the milled material  

Microsoft Academic Search

Due to difficulties in the use of traditional mechanical methods to mill of difficult-to-machine materials (especially in thin section), methods such as chemical milling or etching have commonly been employed. However, increasing legislative restriction on disposal of effluent has resulted in an increase in the environmental costs of such processes, and has prompted examination of alternative processes for milling to

G. Fowler; P. H. Shipway; I. R. Pashby

2005-01-01

157

On the mechanisms of abrasive wear of polyamide fibres  

Microsoft Academic Search

The abrasion resistance of fibres is a basic property in the textile industry since the fibres can be damaged during the manufacturing process. To understand the fundamental mechanisms of abrasion of 40?m diameter polyamide fibres, a tribometer using a fibre-cylinder contact configuration immersed in water has been developed. This instrumented device controls tribological parameters such as the sliding speed, the

J. Cayer-Barrioz; D. Mazuyer; P. Kapsa; A. Chateauminois; F. Bouquerel

2003-01-01

158

Sand abrasion injury and biomass partitioning in cotton seedlings  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wind blown soil particle abrasion negatively impacts millions of hectares of crops annually. The goal of this study was to examine the effects of wind and wind blown sand abrasion damage on cotton (Gossypium hirsutum L.) seedling biomass partitioning to leaves, stems, and roots. Seedlings of three ...

159

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

160

Devitrifying cupola slag for use in abrasive products  

NASA Astrophysics Data System (ADS)

A value-added abrasive product can be obtained by devitrifying CaO-rich cupola slag glass. The treatment process forms a dense, intertwined, fibrous Mg-wollastonite microstructure that has improved chemical corrosion resistance and a two-fold increase in abrasion resistance (inverse grindability) over the original glass.

Agarwal, G.; Speyer, R. F.

1992-03-01

161

Sand abrasion injury and biomass partitioning in cotton seedlings  

Technology Transfer Automated Retrieval System (TEKTRAN)

Millions of acres of crops are exposed to wind blown sand abrasion injury each year and in many instances the damage is thought to be sufficiently severe to require replanting. The goal of this study was to determine the effects of wind blown sand abrasion duration on cotton seedlings. Seedlings of ...

162

Solidification structure and abrasion resistance of high chromium white irons  

NASA Astrophysics Data System (ADS)

Superior abrasive wear resistance, combined with relatively low production costs, makes high Cr white cast irons (WCIs) particularly attractive for applications in the grinding, milling, and pumping apparatus used to process hard materials. Hypoeutectic, eutectic, and hypereutectic cast iron compositions, containing either 15 or 26 wt pct chromium, were studied with respect to the macrostructural transitions of the castings, solidification paths, and resulting microstructures when poured with varying superheats. Completely equiaxed macrostructures were produced in thick section castings with slightly hypereutectic compositions. High-stress abrasive wear tests were then performed on the various alloys to examine the influence of both macrostructure and microstructure on wear resistance. Results indicated that the alloys with a primarily austenitic matrix had a higher abrasion resistance than similar alloys with a pearlitic/bainitic matrix. Improvement in abrasion resistance was partially attributed to the ability of the austenite to transform to martensite at the wear surface during the abrasion process.

Do?an, Ö. N.; Hawk, J. A.; Laird, G.

1997-06-01

163

Fixed and Growth Mindset in Education and How Grit Helps Students Persist in the Face of Adversity  

ERIC Educational Resources Information Center

Students face a wealth of challenges in college for example a lack of support, sometimes making it difficult to persevere. However, in an academic environment that teaches grit and fosters growth, students can learn to persist. Those who believe intelligence is fixed and cannot be changed exert less effort to succeed. Students who persevere when…

Hochanadel, Aaron; Finamore, Dora

2015-01-01

164

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

165

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

ERIC Educational Resources Information Center

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

Deal, Gerald A.; Montgomery, James A.

166

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

E-print Network

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

Wilkins, David E.

167

BLAST: THE REDSHIFT SURVEY  

SciTech Connect

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

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

2009-12-20

168

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

169

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

170

Post-emergence weed control through abrasion with an approved organic fertilizer  

Technology Transfer Automated Retrieval System (TEKTRAN)

Corn gluten meal (CGM) is an approved organic fertilizer and preemergence herbicide that can be manufactured in the form of grit. This grit was tested for its ability to abrade seedlings of the summer annual weedy grass, Setaria pumila, when plants were in the 1- to 5-leaf stages of growth. It was p...

171

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

172

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...

173

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...

174

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

175

29 CFR 1926.912 - Underwater blasting.  

Code of Federal Regulations, 2011 CFR

...currents from galvanic action of the metals and water. (c) Only water-resistant blasting caps and detonating cords shall be used...blast shall be fired while any person is in the water. (f) Blasting flags shall be...

2011-07-01

176

A blasting additive that renders wastes non hazardous in lead paint abatement projects  

SciTech Connect

Maintenance of steel structures often produces abrasive wastes that are considered toxic and hazardous due to the lead content of the old paint system present in spent abrasives. Environmental regulations in the US and Canada effectively preclude on-site treatment and disposal of these wastes, thereby forcing them into costly transport and secure disposal options. The authors have developed an abrasive additive that allows dry or wet blasting to remove old paint systems, but the resultant wastes are considered non-hazardous and are eligible for recycling or non-hazardous waste disposal, both at sharply reduced costs. The agent does not ``mask`` environmental test results, but does produce a stable residue suitable for long term disposal or reuse. Surface conditions after application of abrasives appear to be amenable to virtually all paint systems tested. The process is in use on an estimated 10% of all steel based lead paint abatement projects in the US, and is experiencing considerable growth in market acceptance. The technology may allow disposal cost reductions in excess of 50%.

Clark, R.; Rapp, D.J.; McGrew, M. [TDJ Group, Cary, IL (United States)

1994-12-31

177

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

178

Mosaic cutters improve, lengthen bit performance in variable, abrasive formations  

SciTech Connect

Mosaic-cutter bits represent an extension of diamond drilling technology. Their more durable cutters and high ROP have made using synthetic diamond technology economical for drilling in variable, abrasive formations. Mosaic-cutter bits are currently drilling with good results in formations that are too abrasive for standard PDC bits in the Far East, North Sea, Alaska, the Rockies, and the Gulf of Mexico. Future developments might include using mosaic cutters on solid-blade bits and on other bit profiles needed in sticky gumbo formations interbedded with abrasive stringers.

Cerkovnik, J.; Mason, K.

1988-05-02

179

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

180

Investigation of Material Improvements to Mitigate the Effects of1 Abrasion Mechanism of Concrete Crosstie2  

E-print Network

to the rail industry.50 To simulate the abrasion mechanism of RSD, a Small-Scale Test for Abrasion Resistance), steel fibers, and the57 application of coatings improve the abrasion resistance of concrete specimens.58Investigation of Material Improvements to Mitigate the Effects of1 Abrasion Mechanism of Concrete

Barkan, Christopher P.L.

181

Effect of metallic aggregate and cement content on abrasion resistance behaviour of  

E-print Network

Effect of metallic aggregate and cement content on abrasion resistance behaviour of concrete O abrasion resistance, such as dams, canals, roads and floors. The abrasion resistance of concrete may on the properties of haematite containing concrete has been reported. The authors report on the abrasion resistance

North Texas, University of

182

Ground Granulated Blast Furnace Slag  

Microsoft Academic Search

\\u000a Ground granulated blast furnace slag (GGBS) is a by-product from the blast-furnaces used to make iron. Blast-furnaces are\\u000a fed with controlled mixture of iron-ore, coke and limestone, and operated at a temperature of about 1,500°C. When iron-ore,\\u000a coke and limestone melt in the blast furnace, two products are produced—molten iron, and molten slag. The molten slag is lighter\\u000a and floats

Rafat Siddique; Mohammad Iqbal Khan

183

Microstructural effects in abrasive wear. Second annual progress report, August 10, 1982-August 12, 1983  

SciTech Connect

Progress has been made in understanding the mechanisms of carbide removal during abrasion by quartz abrasive. In situ SEM scratch tests have demonstrated that carbide fracture is the controlling process in quartz abrasion of white cast irons, suggesting that carbide toughness is a critical parameter in controlling abrasion resistance. A study of surface recrystallization during abrasion has yielded definite evidence of the occurrence of recrystallization in pure Al. A program to investigate the effects of vanadium additions and heat treatments on the abrasion resistance of white cast iron indicate that optimum abrasion resistance as well as optimum spalling resistance may be obtained using a subcritical annealing heat treatment. A new study of the effect of abrasive particle size on abrasion in dual-phase alloys has demonstrated the opposite effect from that observed in single-phase alloys for quartz abrasive, whereas with Al/sub 2/O/sub 3/ particles, dual-phase and single-phase alloys behave more similarly.

Kosel, T.H.

1983-08-12

184

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

Code of Federal Regulations, 2012 CFR

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

2012-01-01

185

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

Code of Federal Regulations, 2013 CFR

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

2013-01-01

186

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

187

Resistance of dentin coating materials against abrasion by toothbrush.  

PubMed

Thin-film coating of root dentin surface by all-in-one adhesives has been shown to be an effective option to prevent root surface caries. The purpose of this study was to investigate the wear resistance against toothbrush abrasion of two all-in-one coating materials; Shield Force (SF) and Hybrid Coat (HC). Bovine dentin surfaces were covered with one of the coating materials; SF or HC. After storage in water for 24 h, the testing surface was subjected to the toothbrush abrasion test up to 50,000 cycles either in water or toothpaste slurry. The remaining thickness of the coating material was measured using SEM. Toothpaste slurry significantly increased rate of tooth brush abrasion of the coating materials. While SF and HC wore at a similar pace under toothbrush abrasion, SF had a thicker coat and could protect dentin longer, up to 50,000 cycles. PMID:23370872

Gando, Iori; Ariyoshi, Meu; Ikeda, Masaomi; Sadr, Alireza; Nikaido, Toru; Tagami, Junji

2013-01-01

188

Improved wound healing in blue LED treated superficial abrasions  

NASA Astrophysics Data System (ADS)

A blue-LED photocoagulator device was designed in order to induce a selective photocoagulation effect in superficial bleeding. An in vivo study in rat back skin evidenced an improved healing process in the LED treated abrasions.

Rossi, Francesca; Tatini, Francesca; Pini, Roberto; Bacci, Stefano; De Siena, Gaetano; Cicchi, Riccardo; Pavone, Francesco; Alfieri, Domenico

2013-06-01

189

Effects of fluvial abrasion on shapes of quartz sand grains  

SciTech Connect

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

Peterson, M.; Mazzullo, J.

1987-09-01

190

Near-surface characteristics of concrete: abrasion resistance  

Microsoft Academic Search

Results of a wide-ranging investigation of the abrasion resistance of concrete are reported and the influence of water\\/cement\\u000a ratio, curing, workability, maximum aggregate size and the constituent materials is discussed. Various other tests, namely\\u000a compressive strength, rebound hardness and permeation (initial surface absorption, intrinsic permeability and vapour diffusivity)\\u000a are examined for their ability to predict the abrasion resistance of concrete.

R. K. Dhir; P. C. Hewlett; Y. N. Chan

1991-01-01

191

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

192

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

193

A modified ASTM G-75 abrasion test helps select candidate alloys for service in a corrosive and abrasive slurry  

SciTech Connect

The design of a hazardous waste immobilization facility at the Savannah River Site (SRS) set material requirements for both abrasion resistance and corrosion resistance in process equipment. Standard ASTM slurry wear test G75 was modified to permit evaluation and comparison of abrasive resistance of candidate materials of construction in the laboratory. However, corrosion was found to contribute significantly to overall metal loss during the testing. Consequently, the abrasive slurry used for the testing was modified by adjusting its chemistry to include appropriate corrosive species. The Miller numbers obtained in the modified G75 Miller abrasion test are described. Pilot plant observations for Type 304L austenitic stainless steel were available. These data were used to generate a Morrison-Miller Ratio'' in order to determine anticipated field abrasion properties for other alloys. Hardness for many of the alloys fell in a narrow range about Rockwell B90, but performance varied significantly in response to slurry chemistry. This effect if synergistic may often be overlooked in the selection process, and it needs to be addressed. Some pilot plant testing of other alloys is essential to confirm the calculated abrasion rates and the approach of using the Morrison-Miller ratio. 6 refs., 3 figs., 5 tabs.

Corbett, R.A.; Morrison, W.S.; Jenkins, C.F. (Corrosion Testing Labs., Inc., Wilmington, DE (USA); Westinghouse Savannah River Co., Aiken, SC (USA))

1989-01-01

194

Noise and blast  

NASA Technical Reports Server (NTRS)

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

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

1973-01-01

195

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

196

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

197

Weldability of an abrasion-resistant steel  

SciTech Connect

The welding performance of a low-carbon-equivalent, abrasion-resistant steel newly developed for the mining industry was studied using a combination of simulative and actual weldability tests. The susceptibility to hydrogen-induced cracking in the weld-metal and heat-affected zones (HAZ), as well as the potential loss of strength and toughness in the HAZ, were evaluated. Simulative testing included the use of the Gleeble 1500 thermomechanical simulator to produce single and multiple-pass weld HAZ microstructures on CVN-size specimens. The effects of heat input, interpass temperature, and post-weld heat treatment (PWHT) on the HAZ microstructure and properties were determined. Additionally, a computer software was used to predict theoretical HAZ hardnesses and volume fraction of phases as a function of cooling rates. The actual welding tests included the Gapped Bead-on-Plate and the Y-groove tests to determine the weld-metal and HAZ susceptibility to hydrogen-induced cracking. Three heat inputs, two diffusible hydrogen and two weld-metal yield-strength levels were used for the actual welding stage. Good correlation was found between microstructure predictions, physical simulations, and actual weld testing results. The new steel was found to be highly weldable because of the low preheat required to avoid HAZ hydrogen induced cracking. All aspects of weld-metal and HAZ cracking behavior had to be addressed for a complete weldability characterization. It was also found that use of excessive heat inputs and PWHT should be avoided when welding this type of steels.

Adonyi, Y.; Domis, W.F.; Chen, C.C. [U.S. Steel Technical Center, Monroeville, PA (United States)

1995-12-31

198

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

199

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

200

Applications of network BLAST server.  

PubMed

The sequence databases continue to grow at an extraordinary rate. Contributions come from both small laboratories and large-scale projects, such as the Merck EST project. This growth has placed new demands on computational sequence comparison tools such as BLAST. Even now it is no longer practical to evaluate some BLAST reports manually; it is necessary to filter the output by, for example, organism, source, or degree of annotation. The new network BLAST service makes such tools possible. It is also possible to present BLAST output in different formats, such as BLANCE. Perhaps most important of all, it becomes simple to call BLAST from another application, making it one step within an integrated system. This makes the automated preparation of sequence evaluations that include BLAST runs possible. In the near future we expect to see a number of applications that use the network BLAST interface to help molecular biologists search against a database that is growing not only in size but in biological richness. PMID:8743682

Madden, T L; Tatusov, R L; Zhang, J

1996-01-01

201

Recycling of spent abrasive media in nonstructural concrete  

SciTech Connect

Spent abrasive media from bridge repainting operations contain metals which may result in the media being classified as hazardous under the Environmental Protection Agency (EPA) Toxicity Characteristic (TC) criteria. The management of spent abrasive media by recycling it as a component of nonstructural concrete was investigated. Success was measured with respect to the TC criteria for leaching and a compressive strength requirement of 6.9 MPa (1,000 psi). Portland cement, with and without the additives used, successfully immobilized the metals present in the media. However, not all of the mixes prepared set, indicating that there is a limit to the amount of media that can be recycled in a concrete product. Mixes incorporating 100% unseparated spent abrasive sand and dust or slag in place of clean sand successfully met the project criteria. Mixes containing up to 25% addition of separated spent abrasive dust met the project criteria with the inclusion of appropriate mix additives. Based on results from this and earlier studies, the Texas Department of Transportation has begun to recycle spent abrasive media using Portland cement.

Webster, M.T.; Loehr, R.C. [Univ. of Texas, Austin, TX (United States)

1996-09-01

202

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

203

Aeolian abrasion on Venus: Preliminary results from the Venus simulator  

NASA Technical Reports Server (NTRS)

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.

1987-01-01

204

Abrasion of Candidate Spacesuit Fabrics by Simulated Lunar Dust  

NASA Technical Reports Server (NTRS)

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

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

2009-01-01

205

Testing of cutting tools with abrasion-resistant coatings  

SciTech Connect

The authors describe work that was carried out to determine the possibility of using cutting tools with abrasion-resistant coatings of titanium nitride for processing the components of oil-well pumps. For the tests, 40 tetra- and pentahedral nonsharpenable blades with abrasion-resistant titanium nitride coating were produced. Pentahedral blades were used for machining bushes of steels 38Kh2MYuA and 40Kh on lathe model 1N730. Tests of tetrahedral blades of alloy T15K6 with and without abrasion-resistant coatings were carried out by machining and boring of thrust collars of steel 39Kh13 after thermal treatment and also for machining of nozzle cutters made of high-speed steel R6M5 before thermal treatment.

Iskanderov, I.N.; Muradov, A.M.; Kerimov, A.M.

1987-01-01

206

Blast From the Past  

NSDL National Science Digital Library

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

207

Preliminary observations of chondral abrasion in a canine model.  

PubMed Central

Articular cartilage repair was followed for one year in skeletally mature dogs after destabilisation by anterior cruciate ligament transection of the stifle joint (CT), abrasion of the inferior medial condyle (ABR) to bleeding bone, or anterior cruciate transection followed by chondral abrasion (CT/ABR). ABR animals formed repair cartilage at the abrasion site (ABR and CT/ABR) at six months as determined by arthroscopy and at necropsy. CT and CT/ABR animals had an additional cartilage ulcer on the superior aspect of the medial condyle. The abraded site extended in CT/ABR condyles. Repair cartilage (ABR and CT/ABR) contained reduced amounts of proteoglycan as seen by histological loss of safranin O staining and reduced uronic acid content. Fibrocartilage was suggested by histological appearance, hypocellularity, and a higher hydroxyproline content. In contrast with ABR animals, the repair cartilage in the CT/ABR animals contained near normal amounts of hydroxyproline. Collagen profiles of abrasion site repair cartilage in ABR animals had more types I and V collagens, similar amounts of type VI collagen, and decreased amounts of types II, IX, and XI collagens than CT/ABR animals. The results of this study are consistent with abrasion chondroplasty leading to a repair cartilage. Despite extended ulcers, repair cartilage from the destabilised joint (CT/ABR) animals was more hyaline-like in its hydroxyproline content and collagen composition than repair cartilage from the stable joint (ABR animals). In these models additional measures appear to be needed as the defects induced by abrasion chondroplasty did not form a functional hyaline cartilage. Images PMID:1417137

Altman, R D; Kates, J; Chun, L E; Dean, D D; Eyre, D

1992-01-01

208

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

209

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)

2010-10-26

210

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

211

Use of a two-body belt abrasion test to measure the grindability of advanced ceramic materials  

SciTech Connect

Structural materials, such as superalloys, intermetallic alloys and engineering ceramics, have been developed to achieve high hardness, high temperature strength, and high fracture toughness. However, these strong materials also tend to be difficult to grind and finish. In the 1990's, the US Department of Energy supported a series of projects to help reduce the cost of machining advanced ceramics. The same properties that make engineering materials attractive for use on severe thermal and mechanical environments (e.g., high hardness, high temperature strength, high fracture toughness) generally tend to make those materials difficult to grind and finish. In the mid-1990's, a belt abrasion test was developed under subcontract to Oak Ridge National Laboratory to help to assess the grindability of structural ceramic materials. The procedure involves applying a 10 N normal force to the end face of a 3 x 4 mm cross-section test bar for 30 seconds which is rubbed against a wet, 220 grit diamond belt moving at 10 m/s. By measuring the change in the bar length after at least six 30-second tests, a belt grindability index is computed and expressed using the same units as a traditional wear factor (i.e., mm{sup 3}/N-m). The test has shown an excellent capability to discriminate not only between ceramics of different basic compositions, e.g., Al{sub 2}O{sub 3}, SiC, and Si{sub 3}N{sub 4}, but also between different lots of the same basic ceramic. Test-to-test variability decreases if the belt is worn in on the material of interest. The surface roughness of the abraded ends of the test specimens does not correlate directly with the belt grindability index, but instead reflects another attribute of grindability; namely the ability of a material to abrade smoothly without leaving excessive rough and pitted areas.

Blau, P.J.; Zanoria, E.S.

1998-07-01

212

Field evidence of two-phase abrasion process  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

213

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

214

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

215

Three-body abrasive wear of short glass fibre polyester composite  

Microsoft Academic Search

Short E-glass fibre-reinforced polyester composites with and without filler have been studied for the low stress abrasive wear behaviour carried out using Rubber Wheel Abrasion Test (RWAT) apparatus. In the present investigation, angular silica sand particles of size ranging between 100–200 and 200–300 ?m were used as dry and loose abrasives. The volume loss of the composite during three-body abrasion

Navin Chand; Ajay Naik; Somit Neogi

2000-01-01

216

Lead concentrations in tissues of marsh birds: relationship of feeding habits and grit preference to spent shot ingestion  

SciTech Connect

The toxic effects of lead shot ingestion on waterfowl are well documented. During the summer of 1982, a random sample of marsh birds from the upper Texas coast indicated a relatively high incidence of shot ingestion in several species. In addition, lead and arsenic levels in bones of these species were correlated with the presence of ingested shot. This paper addresses possible reasons why some species are affected and others are not, in particular the relationship between feeding habits and size of grit which is found in the gizzards of each species.

Hall, S.L.; Fisher, F.M. Jr.

1985-07-01

217

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

218

Dynamic elastic–plastic analysis of 3D deformation in abrasive waterjet machining  

Microsoft Academic Search

Although several theoretical and experimental models have been developed for abrasive waterjet machining (AWJM), the exact nature of erosion is not yet understood. This paper presents an attempt to model AWJM using the finite element method (FEM) in order to explain the abrasive particle–workpiece interaction process. Also, the model predicts the depth of deformation as a result of abrasive particle

A. I Hassan; J Kosmol

2001-01-01

219

An energetic approach to abrasive wear of a martensitic stainless steel  

Microsoft Academic Search

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

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

2000-01-01

220

ABRASION RESISTANCE OF CONCRETE AS INFLUENCED BY INCLUSION OF FLY ASH  

E-print Network

ABRASION RESISTANCE OF CONCRETE AS INFLUENCED BY INCLUSION OF FLY ASH Tarun R. Naik*, Shiw S. Singh abrasion resistance of high-volume fly ash concrete. A reference plain portland cement concrete with or without fly ash passed the abrasion resistance requirements per ASTM C-779, Procedure B. An accelerated

Wisconsin-Milwaukee, University of

221

ABRASION RESISTANCE OF HIGH-STRENGTH CONCRETE MADE WITH CLASS C FLY ASH  

E-print Network

ABRASION RESISTANCE OF HIGH-STRENGTH CONCRETE MADE WITH CLASS C FLY ASH Tarun R. Naik, Ph.D., P Street Milwaukee, WI 53211 #12;-1- ABRASION RESISTANCE OF HIGH-STRENGTH CONCRETE MADE WITH CLASS C FLY to evaluate the abrasion resistance of concrete proportioned to have five levels of cement replacements (15

Wisconsin-Milwaukee, University of

222

Effect of Source of Fly Ash on Abrasion Resistance of Concrete  

E-print Network

Effect of Source of Fly Ash on Abrasion Resistance of Concrete Tarun R. Naik1 ; Shiw S. Singh2 and amount of fly ash on abrasion resistance of concrete. A reference concrete was proportioned to have a 28 the abrasion resistance of this high-strength concrete. The effects of both the source and the amount of fly

Wisconsin-Milwaukee, University of

223

Property maps for abrasion resistance of materials F.W. Zok *, A. Miserez  

E-print Network

Property maps for abrasion resistance of materials F.W. Zok *, A. Miserez Materials Department the plastic zone at sharp contacts. Material property groups that characterize abrasion resistance emerge from with external bodies [1]. Despite its technological importance, the notion of abrasion resistance as a material

Zok, Frank

224

Solidification structure and abrasion resistance of high chromium white irons  

Microsoft Academic Search

Superior abrasive wear resistance, combined with relatively low production costs, makes high Cr white cast irons (WCIs) particularly attractive for applications in the grinding, milling, and pumping apparatus used to process hard materials. Hypoeutectic, eutectic, and hypereutectic cast iron compositions, containing either 15 or 26 wt pct chromium, were studied with respect to the macrostructural transitions of the castings, solidification

Ö. N. Dogan; J. A. Hawk; G. Laird

1997-01-01

225

A nonmineralized approach to abrasion-resistant biomaterials  

E-print Network

, and approved June 22, 2007 (received for review March 12, 2007) The tooth-like mouthparts of some animals of biostructural materials. In this study, the abrasion resistance of the jaws of one such animal, the bloodworm Glycera dibranchiata, has been evaluated by nanoindentation, nanoscratching, and wear testing. The hardest

Zok, Frank

226

Innovative decontamination technology by abrasion in vibratory vessels  

SciTech Connect

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

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

2007-07-01

227

A nonmineralized approach to abrasion-resistant biomaterials  

PubMed Central

The tooth-like mouthparts of some animals consist of biomacromolecular scaffolds with few mineral components, making them intriguing paradigms of biostructural materials. In this study, the abrasion resistance of the jaws of one such animal, the bloodworm Glycera dibranchiata, has been evaluated by nanoindentation, nanoscratching, and wear testing. The hardest, stiffest, and most abrasion-resistant materials are found within a thin (<3 ?m) surface layer near the jaw tip and a thicker (10–20 ?m) subsurface layer, both rich in unmineralized Cu. These results are consistent with the supposition that Cu ions are involved in the formation of intermolecular coordination complexes between proteins, creating a highly cross-linked molecular network. The intervening layer contains aligned atacamite [Cu2(OH)3Cl] fibers and exhibits hardness and stiffness (transverse to the alignment direction) that are only slightly higher than those of the bulk material but lower than those of the two Cu-rich layers. Furthermore, the atacamite-containing layer is the least abrasion-resistant, by a factor of ?3, even relative to the bulk material. These observations are broadly consistent with the behavior of engineering polymer composites with hard fiber or particulate reinforcements. The alignment of fibers parallel to the jaw surface, and the fiber proximity to the surface, are both suggestive of a natural adaptation to enhance bending stiffness and strength rather than to endow the surface regions with enhanced abrasion resistance. PMID:17702868

Pontin, Michael G.; Moses, Dana N.; Waite, J. Herbert; Zok, Frank W.

2007-01-01

228

21 CFR 872.6010 - Abrasive device and accessories.  

Code of Federal Regulations, 2010 CFR

...intended to remove excessive restorative materials, such as gold, and to smooth rough surfaces from oral restorations, such as crowns. The device is attached to a shank that is held by a handpiece. The device includes the abrasive disk, guard for an...

2010-04-01

229

21 CFR 872.6010 - Abrasive device and accessories.  

Code of Federal Regulations, 2013 CFR

...intended to remove excessive restorative materials, such as gold, and to smooth rough surfaces from oral restorations, such as crowns. The device is attached to a shank that is held by a handpiece. The device includes the abrasive disk, guard for an...

2013-04-01

230

Abrasion resistance of Cu based bulk metallic glasses  

Microsoft Academic Search

The abrasive wear behaviors of three copper based bulk metallic glasses have been studied using pin-on-disc measurement and compared with both annealed metallic glass and 304 stainless steel. The volume loss increases linearly with sliding distance. However, the wear resistances of metallic glasses are not directly proportional to hardness and do not follow the wear law. The wear resistance increases

Rex C. Y. Tam; C. H. Shek

2004-01-01

231

Surface carbonization of titanium for abrasion-resistant implant materials.  

PubMed

Carbide layer was formed on the surface of Ti by heating in hydrocarbon atmosphere (benzene C6H6) at 1000-1400 degrees C using a high frequency induction heating method. Physical and mechanical properties of carbide-coated Ti were investigated to examine its potential as an abrasion-resistant implant material. Scanning electron microscopy (SEM) showed that the surface of Ti was covered with fine grains of 1-4 microm diameter, depending on heating conditions. In addition, carbide layer of about 1-25 microm thickness was observed on the cross-section of specimens by SEM and energy dispersive spectroscopy. Vickers hardness of surface carbide was found to be more than 2000. Further, Martens scratch test and ultrasonic scaler abrasion test showed that the indentation depth and width of carbide-coated Ti were much smaller than pure Ti, thereby confirming its high abrasion resistance. These results showed that for Ti implant materials that require high abrasion resistance, such as the abutment for dental implants, surface carbide coatings would be an effective means to improve their wear properties. PMID:17621941

Zhu, Yuhe; Watari, Fumio

2007-03-01

232

A nonmineralized approach to abrasion-resistant biomaterials.  

PubMed

The tooth-like mouthparts of some animals consist of biomacromolecular scaffolds with few mineral components, making them intriguing paradigms of biostructural materials. In this study, the abrasion resistance of the jaws of one such animal, the bloodworm Glycera dibranchiata, has been evaluated by nanoindentation, nanoscratching, and wear testing. The hardest, stiffest, and most abrasion-resistant materials are found within a thin (<3 microm) surface layer near the jaw tip and a thicker (10-20 microm) subsurface layer, both rich in unmineralized Cu. These results are consistent with the supposition that Cu ions are involved in the formation of intermolecular coordination complexes between proteins, creating a highly cross-linked molecular network. The intervening layer contains aligned atacamite [Cu(2)(OH)(3)Cl] fibers and exhibits hardness and stiffness (transverse to the alignment direction) that are only slightly higher than those of the bulk material but lower than those of the two Cu-rich layers. Furthermore, the atacamite-containing layer is the least abrasion-resistant, by a factor of approximately 3, even relative to the bulk material. These observations are broadly consistent with the behavior of engineering polymer composites with hard fiber or particulate reinforcements. The alignment of fibers parallel to the jaw surface, and the fiber proximity to the surface, are both suggestive of a natural adaptation to enhance bending stiffness and strength rather than to endow the surface regions with enhanced abrasion resistance. PMID:17702868

Pontin, Michael G; Moses, Dana N; Waite, J Herbert; Zok, Frank W

2007-08-21

233

Membrane characteristics for biological blast overpressure testing using blast simulators.  

PubMed

Blast simulators often use passive-rupture membranes to generate shock waves similar to free-field blasts. The purpose of this study was to compare rupture patterns and pressure traces of three distinct membrane materials for biological and biomechanical blast studies. An Advanced Blast Simulator (ABS) located at the Center for Injury Biomechanics at Virginia Tech was used to test membrane characteristics. Acetate, Mylar, and aluminum sheets with different thicknesses were used to obtain pressures between 70?210 kPa. Static pressure was measured inside the tube at the test section using piezoelectric pressure sensors. Peak overpressure, positive duration, and positive impulse were calculated for each test. Rupture patterns and characteristic pressure traces were unique to each membrane type and thickness. Shock wave speed ranged between 1.2-1.8 Mach for static overpressures of 70?210 kPa. Acetate membranes fragmented sending pieces down the tube, but produced ideal (Friedlander) pressure traces. Mylar membranes bulged without fragmenting, but produced less-than-ideal pressure traces. Aluminum membranes did not fragment and produced ideal pressure traces. However, the cost of manufacturing and characterizing aluminum membranes should be considered during membrane selection. This study illustrates the advantages and disadvantages of using Mylar, acetate, and aluminum for passive rupture membranes for blast simulators. PMID:25405432

Alphonse, Vanessa D; Siva Sai Sujith Sajja, Venkata; Kemper, Andrew R; Rizel, Dave V; Duma, Stefan M; VandeVord, Pamela J

2014-01-01

234

Analysis of magnetic abrasive finishing with slotted magnetic pole  

NASA Astrophysics Data System (ADS)

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

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

2004-06-01

235

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

236

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....

237

29 CFR 1926.912 - Underwater blasting.  

Code of Federal Regulations, 2010 CFR

...loading tube when tube is necessary. (d) No blast shall be fired while any vessel under way is closer...anchored within 1,500 feet shall be notified before a blast is fired. (e) No blast shall be fired while any swimming or diving...

2010-07-01

238

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

239

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

PubMed

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

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

2014-01-01

240

Development and Performance Evaluation of Abrasion Tester Using Water Jet with Sand  

NASA Astrophysics Data System (ADS)

In concrete structures used for irrigation and drainage, there occurs a kind of deterioration that mortar in concrete matrix is abraded selectively. To estimate the progress of such abrasion and evaluate the resistivity to abrasion of repair material, a prototype of abrasion tester was developed. It sprays water including sand to specimens. In this research, the comparative tests between this prototype, Taber type abrasion tester and Water jet abrasion tester ware executed using the specimens of concrete, Polymer Cement Mortar and High Performance Fiber Reinforced Cement Composite. As a result, it was clarified that the prototype can simulate the selective abrasion more quickly than existing method. Therefore, this prototype can be used to evaluate the resistivity to abrasion of repair material.

Natsuka, Isamu; Ueno, Kazuhiro; Tokashiki, Masaru; Ishii, Masayuki

241

Abrasion in pyroclastic density currents: Insights from tumbling experiments  

NASA Astrophysics Data System (ADS)

During granular mass movements of any kind, particles may interact with one another. The degree of interaction is a function of several variables including; grain-size distribution, particle concentration, density stratification and degree of fluidisation. The impact of particle interaction is additionally influenced by the relative speed, impact angle and clast temperature. Thus, both source conditions and transport-related processes are expected to influence the flow dynamics of pyroclastic density currents and their subsequent deposition. Here, we use tumbling experiments to shed light on the susceptibility of porous clasts to abrasion. We investigated the abrasion of unaltered volcanic rocks (5.7-80 vol.% porosity) from Unzen (Japan), Bezymianny (Russia) and Santorini (Greece) volcanoes as well as one synthetic analogue material, an insulating material with the trade name Foamglas® (95 vol.% porosity). Each experiment started with angular fragments generated in a jaw crusher from larger clasts. Two experimental series were performed; on samples with narrow and broader grain-size distributions, respectively. The dry samples were subject to rotational movement at constant speed and ambient temperature in a gum rotational tumbler for durations of 15, 30, 45, 60 and 120 min. The amount of volcanic ash (particles <2 mm) generated was evaluated as a function of experimental duration and sample porosity. We term “abrasion” as the ash fraction generated during the experiments. The observed increase of “abrasion” with increasing sample porosity and experimental duration is initially non-linear but becomes linear for experiments of 30 min duration or longer. For any given sample, abrasion appears to be more effective for coarser samples and larger initial mass. The observed range of ash generated in our experiments is between 1 and 35 wt.%. We find that this amount generally increases with increasing initial clast size or increasing breadth of the initial grain-size distribution. Despite the limits in the complexity that is experimentally attainable in this simulation of ash generation, our results clearly testify the rapid and efficient generation of ash by abrasion, strongly influenced by the material properties (e.g., crystallinity, pore textures).

Kueppers, Ulrich; Putz, Constanze; Spieler, Oliver; Dingwell, Donald B.

2012-01-01

242

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

243

Blast waves in rotating media.  

NASA Technical Reports Server (NTRS)

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

Rossner, L. F.

1972-01-01

244

Blast vulnerability detected in novel blast-resistant germplasm.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Previous research in artificially inoculated greenhouse tests and field nurseries identified new rice germplasm accession as being resistant to the common blast (Pyricularia grisea) races found in Arkansas (IB-1, IB-49, IC-17, IE-1, IE-1k, IG-1, and IH-1) and eliminated those accessions with major b...

245

Methods for predicting rubble motion during blasting  

SciTech Connect

Recent applications of explosives and blasting agents to rubble rock have led to requirements for more elaborate design and analysis methods. In most blasting uses, it is necessary not only to fracture the rock, but also to move the broken rubble in a predictable manner. Many in situ extraction techniques require rubblization to take place in a confined region where rock motion is a predominate factor in creating a permeable broken bed. In this paper, two analytical methods are presented which describe the large rubble motion during blasting. These methods provide the blast designer with a tool for evaluation and further refinement of blasting patterns and timing sequences.

Schamaun, J.T.

1984-01-01

246

Self inflicted corneal abrasions due to delusional parasitosis  

PubMed Central

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

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

2011-01-01

247

Abrasion Testing of Critical Components of Hydrokinetic Devices  

SciTech Connect

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

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

2013-12-06

248

Proper bit design improves penetration rate in abrasive horizontal wells  

SciTech Connect

Overall drilling penetration rates nearly tripled, and drill bit life nearly doubled compared to conventional bits when specially designed natural diamond and polycrystalline diamond compact (PDC) bits were used during a seven-well horizontal drilling program. The improvement in drilling performance from better-designed bits lowered drilling costs at ANR Pipeline Co.'s Reed City gas storage field in Michigan. Laboratory tests with scaled down bits used on abrasive cores helped determine the optimum design for drilling the gas storage wells. The laboratory test results and actual field data were used to develop a matrix-body natural diamond bit, which was later modified to become a matrix-body, blade-type polycrystalline diamond compact bit. This bit had excellent penetration rates and abrasion resistance. The paper describes the background to the project, bit selection, natural diamond bits, field results, new bit designs, and field results from the new design.

Gentges, R.J. (ANR Pipeline Co., Detroit, MI (United States))

1993-08-09

249

Wind abrasion on Venus: A means for experimental investigations  

NASA Astrophysics Data System (ADS)

A study to determine the feasibility of conducting experiments to simulate the aeolian environment on Venus as related to wind abrasion was completed. Ideally, such experiments should involve complete investigation of weathering, in which mechanical, thermal, and chemical parameters are taken into account. This is particularly important for Venus, where atmospheric temperatures and pressures at the surface produce an environment which is equivalent to low or medium grade metamorphic conditions on Earth. Details that describe the Venus Aeolian Abrasion Device (VAAD) are included. The VAAD device would enable experiments to be conducted with the same chemistry, temperature, pressure, and other physical properties of the Venus atmosphere near the surface. The proposed device enables the important aeolian parameters to be controlled and monitored, including particle size, velocity, impact-angle and flux, atmospheric pressure, temperature, and gas composition.

Greeley, R.; Marshall, J. R.

1984-04-01

250

Abrasive-waterjet machining of ceramic-coated materials  

NASA Astrophysics Data System (ADS)

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

Hashish, M.; Whalen, J.

1991-09-01

251

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

252

Erosion, cavitation, and abrasion resistance of choke trim materials  

SciTech Connect

An experimental investigation was performed to determine the relative erosion, abrasion and cavitation resistance characteristics of selected materials. Testing was conducted under controlled laboratory conditions to simulate service conditions encountered in production and injection chokes. The testing effort is ongoing. The data accumulated allow informed material selection of conventional and novel trim for all chokes, valves, flow metering orifices, fixed beans and other devices used during drilling, completion and production of offshore and onshore oil and gas wells. Sintered silicon carbide, and tungsten carbide with minimum binder content were the most erosion and abrasion resistant of the materials tested. Cobalt base alloys bar and nickelchrome alloy 625 bar proved to be most cavitation resistant.

Seger, F.O.; Maroofian, I.

1984-05-01

253

A physically-based abrasive wear model for composite materials  

SciTech Connect

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

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

2001-05-01

254

Optimizing fracture toughness and abrasion resistance in white cast irons  

Microsoft Academic Search

A series of twelve Cr-Mo white irons varying in carbide volume from 7 to 45 pct were tested for dynamic fracture toughness\\u000a and wet sand abrasion resistance. Carbon content was varied from 1.4 to 3.9 pct. Two matrix microstructures were employed,\\u000a and the compositions (copper and chromium content) were varied to assure constant matrix compositions. Chromium was varied\\u000a from 11.6

Karl-Heinz Zum Gahr; Douglas V. Doane

1980-01-01

255

Solidification structure and abrasion resistance of high chromium white irons  

Microsoft Academic Search

Superior abrasive wear resistance, combined with relatively low production costs, makes high Cr white cast irons (WCIs) particularly\\u000a attractive for applications in the grinding, milling, and pumping apparatus used to process hard materials. Hypoeutectic,\\u000a eutectic, and hypereutectic cast iron compositions, containing either 15 or 26 wt pct chromium, were studied with respect\\u000a to the macrostructural transitions of the castings, solidification

Ö. N. Do?an; J. A. Hawk; G. II Laird; II George

1997-01-01

256

Abrasion resistance of two types of nonabsorbable braided suture  

Microsoft Academic Search

Purpose: The purpose of this study was to compare the abrasion resistance of different types of non-absorbable braided sutures under varying in vitro conditions of cyclic loading. Type of Study: Biomechanical study. Methods: Two types of nonabsorbable braided sutures were used in this study, No. 2 Ethibond and No. 2 Fiberwire, combined with 5 different anchors: 5.0-mm Corkscrew anchor, 5.0-mm

Ian K. Y Lo; Stephen S Burkhart; Kyriacos Athanasiou

2004-01-01

257

Characterization of Effective Parameters in Abrasive Waterjet Rock Cutting  

NASA Astrophysics Data System (ADS)

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

Oh, Tae-Min; Cho, Gye-Chun

2014-03-01

258

Abrasion of Candidate Spacesuit Fabrics by Simulated Lunar Dust  

NASA Technical Reports Server (NTRS)

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

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

2009-01-01

259

Drill and Blast Tunneling Practices  

Microsoft Academic Search

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

Gerhard Girmscheid; Cliff Schexnayder

2002-01-01

260

Rice blast disease in Texas  

Technology Transfer Automated Retrieval System (TEKTRAN)

Rice is an important agricultural commodity in Texas, with an economic impact of more than $1 billion annually. Rice blast, caused by Magnaporthe oryzae, is one of the most devastating diseases in rice. Texas Rice Belt provides a warm, humid climate favorable for the infection and reproduction of M....

261

Microstructural effects in abrasive wear: Final report for period September 15, 1981--March 14, 1986  

SciTech Connect

This report summarizes research performed on abrasion of metallic alloys. The work was designed to improve our understanding of the factors affecting abrasion rates in two-phase alloys containing large, hard second-phase particles (SPPs) such as carbides, since this class of alloys generally has very high abrasion resistance owing to the presence of such carbides. The project was divided into sections dealing with material removal in the carbide and matrix phases. The materials studied included Stellite and high Cr-Mo white cast irons and a set of specially prepared model alloys containing one of six types of artificial SPPs dispersed in a sintered matrix of pure Cu. Scratch tests were employed to simulate abrasion mechanisms, and specially designed scratch test systems were fabricated to permit scratch testing in-situ in the scanning electron microscope (SEM) and to permit scratches to be made at fixed depths of cut rather than fixed loads. Three types of abrasion tests were employed; a dry-sand rubber wheel abrasion test; a low-speed ''gouging'' abrasion test employing a special low-speed Al/sub 2/O/sub 3/ grinding wheel; and a pin-on-disc abrasion test using abrasive paper. Abrasive type and size was varied in the rubber wheel and the pin-on-disc tests. 27 refs., 10 figs., 5 tabs.

Kosel, T.H.

1988-03-08

262

Comparison of Blast-Induced Damage Between Presplit and Smooth Blasting of High Rock Slope  

NASA Astrophysics Data System (ADS)

This paper focuses on the comparison of damage induced by smooth blasting and presplit blasting based on the excavation of high rock slope. The whole damage process of the smooth blasting and presplit blasting excavation method is studied by using a cumulative blasting damage numerical simulation technology based on the secondary development of the dynamic finite element code LS-DYNA. The results demonstrate that, in the case of contour blasting with the method of smooth blasting, the total damage of rock slope is a result of cumulated damage induced by the production hole, buffering hole, and smooth hole. Among the total damage, the blasting of the production hole is the main resource, followed by the smooth and buffering holes. For the presplit blasting, the final damage of rock slope is mainly induced by presplit blasting itself. The spatial distribution characteristics of the final damage zone of two methods are compared. Two classes of damage zone could be found in smooth blasting excavation; one of them is the columnar high-degree damage zone around the slope surface and the other is the low-degree damage zone located in the middle of the slope. But in the case of presplit blasting, there is only the columnar high-degree damage zone around the slope surface. Finally, a damage control suggestion for two blasting excavation methods is proposed and verified based on the excavation of the temporary shiplock slopes of the Three Gorges Project in China.

Hu, Yingguo; Lu, Wenbo; Chen, Ming; Yan, Peng; Yang, Jianhua

2014-07-01

263

Radioactive labeling in the study of abrasion of hard tooth tissue  

Microsoft Academic Search

Labeling the surface of hard tooth tissue samples by the nuclear recoil effect in radioactive decay was applied to study abrasion\\u000a caused by abrasive components of tooth-pastes.222Rn and its short-lived decay products were implanted into the surface in vacuum. For this purpose irradiation was applied\\u000a to sample placed very close to thin226Ra source. Measuring the activity before and after abrasion

A. Gosman; D. Houšová; J. Koní?ek; L. Doležalová

1998-01-01

264

Free abrasive wear behavior of UHMWPE composites filled with wollastonite fibers  

Microsoft Academic Search

Ultra high molecular weight polyethylene (UHMWPE) composites filled with wollastonite fibers of aspect ratios 10:1, 15:1 and 20:1 have been prepared. The wollastonite fibers were modified by the silane–titanate combined modification method. The free abrasive wear of the composites was tested on a rotary disc abrasive wear tester simulating soil conditions, using quartz sand as the abrasive medium. It has

Jin Tong; Yunhai Ma; R. D. Arnell; Luquan Ren

2006-01-01

265

Friction and abrasion resistance of cast aluminum alloy-fly ash composites  

Microsoft Academic Search

The abrasive wear properties of stir-cast A356 aluminum alloy-5 vol pct fly ash composite were tested against hard SiC\\u000a p\\u000a abrasive paper and compared to those of the A356 base alloy. The results indicate that the abrasive wear resistance of aluminum-fly\\u000a ash composite is similar to that of aluminum-alumina fiber composite and is superior to that of the matrix alloy

P. K. Rohatgi; R. Q. Guo; P. Huang; S. Ray

1997-01-01

266

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

Microsoft Academic Search

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

M. M. Stack; M. T. Mathew

2004-01-01

267

30 CFR 57.6306 - Loading, blasting, and security.  

Code of Federal Regulations, 2010 CFR

...explosive materials or initiating systems are brought to the blast site, the blast site shall be attended; barricaded and posted with warning...loading begins, the only activities permitted within the blast site shall be those activities directly...

2010-07-01

268

30 CFR 56.6306 - Loading, blasting, and security.  

Code of Federal Regulations, 2010 CFR

...explosive materials or initiating systems are brought to the blast site, the blast site shall be attended; barricaded and posted with warning...loading begins, the only activities permitted within the blast site shall be those activities directly...

2010-07-01

269

HIGH PRODUCTIVITY VACUUM BLASTING SYSTEM  

SciTech Connect

The Department of Energy (DOE) needs improved technologies to decontaminate large areas of both concrete and steel surfaces. The technology should have high operational efficiency, minimize exposures to workers, and produce low levels of secondary waste. In order to meet the DOE's needs, an applied research and development project for the improvement of a current decontamination technology, Vacuum Blasting, is proposed. The objective of this project is to improve the productivity and lower the expense of the existing vacuum blasting technology which has been widely used in DOE sites for removing radioactive contamination, PCBs, and lead-based paint. The proposed work would increase the productivity rate and provide safe and cost-effective decontamination of the DOE sites.

William S. McPhee

2001-08-31

270

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

271

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

272

The Next Generation BLAST Experiment  

E-print Network

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

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

2014-01-01

273

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

274

Diffuse corneal abrasion after ocular exposure to laundry detergent pod.  

PubMed

Although ocular injury from alkaline household cleaning products is well described, there is less known about the significance and extent of injury with ocular exposure to detergent pods. We report a 12-month-old with diffuse corneal abrasion caused by ocular contact with a laundry detergent pod. In addition to the known risks with aspiration with detergent pods, the potential for severe ocular injury is important for parents and clinicians to recognize. Children with ocular exposure to detergent pods should seek immediate medical care. PMID:25422858

Whitney, Rachel E; Baum, Carl R; Aronson, Paul L

2015-02-01

275

Solution of the Roth-Marques-Durian rotational abrasion model  

NASA Astrophysics Data System (ADS)

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

Chen, Bryan Gin-Ge

2011-03-01

276

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

E-print Network

after midnight on March 24, 1989, the 987-foot tank vessel Exxon Valdez, of the Exxon shipping company-million gallons were dumped into the Prince William Sound. The spilled oil slick scattered over 3000 mi2

Kim, Jongwon

277

Effect of mechanical abrasion on the viability, disruption and germination of spores of Bacillus subtilis  

PubMed Central

Aims To elucidate the factors influencing the sensitivity of Bacillus subtilis spores to killing and disruption by mechanical abrasion, and the mechanism of stimulation of spore germination by abrasion. Methods and Results Spores of B. subtilis strains were abraded by shaking with glass beads in liquid or the dry state, and spore killing, disruption and germination were determined. Dormant spores were more resistant to killing and disruption by abrasion than were growing cells or germinated spores. However, dormant spores of the wild-type strain with or without most coat proteins removed, spores of strains with mutations causing spore coat defects, spores lacking their large depot of dipicolinic acid (DPA) and spores with defects in the germination process exhibited essentially identical rates of killing and disruption by abrasion. When spores lacking all nutrient germinant receptors were enumerated by plating directly on nutrient medium, abrasion increased the plating efficiency of these spores before killing them. Spores lacking all nutrient receptors and either of the two redundant cortex-lytic enzymes behaved similarly in this regard, but the plating efficiency of spores lacking both cortex-lytic enzymes was not stimulated by abrasion. Conclusions Dormant spores are more resistant to killing and disruption by abrasion than are growing cells or germinated spores, and neither the complete coats nor DPA are important in spore resistance to such treatments. Germination is not essential for spore killing by abrasion, although abrasion can trigger spore germination by activation of either of the spore’s cortex-lytic enzymes. Significance and Importance This work provides new insight into the mechanisms of the killing, disruption and germination of spores by abrasion and makes the surprising finding that at least much of the spore coat is not important in spore resistance to abrasion. PMID:16313421

Jones, C.A.; Padula, N.L.; Setlow, P.

2005-01-01

278

ScalaBLAST 2.0: Rapid and robust BLAST calculations on multiprocessor systems  

SciTech Connect

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

Oehmen, Christopher S.; Baxter, Douglas J.

2013-03-15

279

[The characteristics of blast traumatic brain injury].  

PubMed

With the increase in terrorist activity in recent times, the number of blast injuries has also increased in civilian and military settings. In a recent war, the number of patients who suffered blast traumatic brain injury (bTBI) increased, so treatment of bTBI is currently a very important issue. Blast injury is complicated and can be divided into 4 categories: primary, secondary, tertiary, and quaternary. Primary blast injury results from exposure to blast waves; secondary blast injury is trauma caused by fragments of explosive devices; tertiary blast injury is the result of collision with objects; and quaternary blast injury is the result of exposure to toxic and other substances. Blast waves mainly injure air-containing organs such as the lung, bowel, and ear. The brain may also be affected by blast waves. From the clinical perspective, hyperemia and severe cerebral edema occur frequently in patients who sustain significant bTBI. Penetrating or closed head injury caused by the explosion may be associated with vasospasm and pseudoaneurysm formation. Mild traumatic brain injury during war can be associated with posttraumatic stress disorder. To elucidate the mechanism of bTBI, many research works using animal models and computer analysis are underway. Such studies have so far shown that blast waves can cause damage to the brain tissue and cognitive deficits; however, detailed investigations on this topic are still required. Treatment of bTBI patients may require clinical knowledge and skills related to intensive care, neurology, and neurosurgery. Moreover, further research is required in this field. PMID:20697143

Matsumoto, Yoshihisa; Hatano, Ben; Matsushita, Yoshitaro; Nawashiro, Hiroshi; Shima, Katsuji

2010-08-01

280

Concussive brain injury from explosive blast  

PubMed Central

Objective Explosive blast mild traumatic brain injury (mTBI) is associated with a variety of symptoms including memory impairment and posttraumatic stress disorder (PTSD). Explosive shock waves can cause hippocampal injury in a large animal model. We recently reported a method for detecting brain injury in soldiers with explosive blast mTBI using magnetic resonance spectroscopic imaging (MRSI). This method is applied in the study of veterans exposed to blast. Methods The hippocampus of 25 veterans with explosive blast mTBI, 20 controls, and 12 subjects with PTSD but without exposure to explosive blast were studied using MRSI at 7 Tesla. Psychiatric and cognitive assessments were administered to characterize the neuropsychiatric deficits and compare with findings from MRSI. Results Significant reductions in the ratio of N-acetyl aspartate to choline (NAA/Ch) and N-acetyl aspartate to creatine (NAA/Cr) (P < 0.05) were found in the anterior portions of the hippocampus with explosive blast mTBI in comparison to control subjects and were more pronounced in the right hippocampus, which was 15% smaller in volume (P < 0.05). Decreased NAA/Ch and NAA/Cr were not influenced by comorbidities – PTSD, depression, or anxiety. Subjects with PTSD without blast had lesser injury, which tended to be in the posterior hippocampus. Explosive blast mTBI subjects had a reduction in visual memory compared to PTSD without blast. Interpretation The region of the hippocampus injured differentiates explosive blast mTBI from PTSD. MRSI is quite sensitive in detecting and localizing regions of neuronal injury from explosive blast associated with memory impairment. PMID:25493283

de Lanerolle, Nihal C; Hamid, Hamada; Kulas, Joseph; Pan, Jullie W; Czlapinski, Rebecca; Rinaldi, Anthony; Ling, Geoffrey; Bandak, Faris A; Hetherington, Hoby P

2014-01-01

281

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

282

Material removal mechanisms in abrasive vibration polishing of complex molds  

NASA Astrophysics Data System (ADS)

Optical and medical industries are demanding a large variety of optical elements exhibiting complex geometries and multitude opto-functional areas in the range of a few millimeters [1]. Therefore, mold inserts made of steel or carbides must be finished by polishing for the replication of glass and plastic lenses [2]. For polishing theses complex components in the shape of localized cavities or grooves the application of rotating polishing pads is very limited. Established polishing processes are not applicable, so state of the art is a time consuming and therefore expensive polishing procedures by hand. An automated process with conventional polishing machines is impossible because of the complex mold insert geometry. The authors will present the development of a new abrasive polishing process for finishing these complex mold geometries to optical quality. The necessary relative velocity in the contact area between polishing pad and workpiece surface is exclusively realized by vibration motions which is an advantage over vibration assisted rotating polishing processes. The absence of rotation of the pad opens up the possibility to machine new types of surface geometries. The specific influence factors of vibration polishing were analyzed and will be presented. The determination of material removal behavior and polishing effect on planar steel samples has shown that the conventional abrasive polishing hypothesis of Preston is applicable to the novel vibration polishing process. No overlaid chemical material removal appears.

Brinksmeier, E.; Riemer, O.; Schulte, H.

2010-10-01

283

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

284

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

285

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

286

Abrasion Resistant Coating and Method of making the same  

SciTech Connect

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.; Besser, Matthew F.

1999-06-25

287

Process Monitoring Evaluation and Implementation for the Wood Abrasive Machining Process  

PubMed Central

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

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

2010-01-01

288

The abrasion of modern and archaeological bones by mobile sediments: the importance of transport modes  

Microsoft Academic Search

Fresh, weathered, archaeological and fossilized bones were subjected to a series of abrasion experiments using fine sand in an annular flume in order to link bone-surface abrasion to flow regimes and sediment transport modes, compare these effects on bones of different states, and quantify the extent and types of wear occurring. Flow velocities were chosen to replicate the predominant transport

C. E. L. Thompson; S. Ball; T. J. U. Thompson; R. Gowland

2011-01-01

289

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

290

A Material Removal Model for CMP Based on the Contact Mechanics of Pad, Abrasives, and Wafer  

E-print Network

A Material Removal Model for CMP Based on the Contact Mechanics of Pad, Abrasives, and Wafer Dinçer, Massachusetts 02115, USA Applied pressure in chemical mechanical polishing CMP is shared by the two-body pad­wafer and the three-body pad­abrasive­ wafer contacts. The fraction of applied pressure transferred through

MĂĽftĂĽ, Sinan

291

MODELING OF PATTERN DEPENDENCIES IN ABRASIVE-FREE COPPER CHEMICAL MECHANICAL POLISHING PROCESSES  

E-print Network

. Introduction In conventional copper CMP processes, polymeric polishing pads, and slurries containing silica]. Abrasive-free copper CMP processes use the same polishing pads and polishing machines used in conventional dependent model for abrasive-free copper chemical mechanical polishing (CMP) processes, and show comparisons

Boning, Duane S.

292

Process monitoring evaluation and implementation for the wood abrasive machining process.  

PubMed

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

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

2010-01-01

293

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

E-print Network

coefficient, - d Diameter, mm E Energy, J g Gravity, g = 9.81 m/s2 h Specific enthalpy, J / kg L* foc) air-abr Relative to air-abrasive AP Abrasive particle CV Control volume foc Focusing tube o Sapphire

294

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

295

Effect of fine aggregate replacement with Class F fly ash on the abrasion resistance of concrete  

Microsoft Academic Search

This paper presents the abrasion resistance of concrete proportioned to have four levels of fine aggregate replacement (10%, 20%, 30%, and 40%) with Class F fly ash. A control mixture with ordinary Portland cement was designed to have 28 days compressive strength of 26 MPa. Specimens were subjected to abrasion testing in accordance with Indian Standard Specifications (IS: 1237). Tests

Rafat Siddique

2003-01-01

296

Abrasion resistance of concrete as influenced by inclusion of fly ash  

Microsoft Academic Search

This research was conducted to evaluate abrasion resistance of high-volume fly ash concrete. A reference plain portland cement concrete was proportioned to obtain 28-day strength of 41 MPa. Concrete mixtures were also proportioned to have two levels of cement replacements (50 and 70%) with an ASTM Class C fly ash. Abrasion tests were carried out using the rotating cutter method

T. R. Naik; S. S. Singh; M. M. Hossain

1994-01-01

297

Use of Variable Remineralization Periods to Improve the Abrasion Resistance of Previously Eroded Enamel  

Microsoft Academic Search

The objective of the study was to evaluate the period of remineralization needed to re–establish the resistance of eroded enamel against brushing abrasion. Enamel specimens were prepared from 84 polished bovine incisors. The samples were evenly distributed among 7 groups (A–G) and submitted to ten alternating de– and remineralization cycles which included abrasion by toothbrushing. Demineralization was accomplished by immersing

T. Attin; W. Buchalla; M. Gollner; E. Hellwig

2000-01-01

298

Assessing the Frictional and Abrasion-resisting Properties of Hooves and Claws  

Microsoft Academic Search

Hoof abrasion and slips on floors are known to have negative effects on animal health and welfare. This paper describes a new design of test rig for use in a universal materials test machine. The rig enables the frictional and abrasion-resisting properties of hoof horn to be investigated under controlled conditions, in vitro.To assess the performance of the rig, pilot

R. H. C. Bonser; J. W. Farrent; A. M. Taylor

2003-01-01

299

Abrasion resistance of high Cr cast irons at an elevated temperature  

Microsoft Academic Search

A novel wear tester was employed to investigate the comparative abrasive stability of metallic materials at elevated temperatures. This tester consists of a symmetric ?-shaped specimen holder that is rotated in a stainless steel tank filled with quartz sand, and an electrical furnace surrounds this tank to heat the abrasive sand. The test material and its comparative, of a size

Hua-Nan Liu; Michiru Sakamoto; Mikio Nomura; Keisaku Ogi

2001-01-01

300

Bonding and abrasion resistance of geopolymeric repair material made with steel slag  

Microsoft Academic Search

Three repair materials were prepared using cement-based, geopolymeric, or geopolymeric containing steel slag binders. Their mechanical performances such as compressive strength, bond strength and abrasion resistance were examined experimentally. The test results showed that the geopolymeric materials had better repair characteristics than cement-based repair materials, and the addition of steel slag could improve significantly the abrasion resistance of geopolymeric repair.

Shuguang Hu; Hongxi Wang; Gaozhan Zhang; Qingjun Ding

2008-01-01

301

Improving the abrasion resistance of mortar by adding latex and carbon fibers  

Microsoft Academic Search

The abrasion resistance of mortar was found to be significantly improved by the addition of latex (20% by weight of cement), and further improved by the further addition of short carbon fibers (0.27 vol.%). Both effects relate to the increase in tensile strength. The abrasion resistance was also improved by the addition of silica fume (15% by weight of cement),

Zeng-Qiang Shi; D. D. L. Chung

1997-01-01

302

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

303

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

304

Highly concentrated foam formulation for blast mitigation  

DOEpatents

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

305

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

306

Submucous implant of abrasive dental materials in rat tongues: clinical and histological evaluation.  

PubMed

This study evaluated the clinical and histological manifestations produced by the submucuous implant of abrasive dental materials in the rat tongue. A total of 128 rats were divided into 4 groups of 32 rats each, according to the material selected for the implant: Herjos-F prophylactic paste both in its normal composition as well as lacking its abrasive components, SS White pumice stone and the abrasive powder of the 3M finishing and polishing sandpaper. The specimens were submitted to clinical and histological analyses at 30, 60, 90 and 120 days. After 90 days, the formation of nodular lesions in animals implanted with materials containing abrasive substances was observed. Histologically, these materials produced marked chronic granulomatous reactions. Herjos-F prophylactic paste produced the greatest reaction. However, without the abrasive components, this paste caused the mildest tissue reactions, with no inflammatory response, that was seen in a progressively greater number of cases after 90 days. PMID:12238799

Pistóia, Alexandre Dorneles; de Figueiredo, Maria Antonia Zancanaro

2002-01-01

307

Hybrid organic/inorganic coatings for abrasion resistance on plastic and metal substrates  

SciTech Connect

Novel abrasion resistant coatings have been successfully prepared by the sol-gel method. These materials are spin coated onto bisphenol-A polycarbonate, diallyl diglycol carbonate resin (CR-39) sheet, aluminum, and steel substrates and are thermally cured to obtain a transparent coating of a few microns in thickness. Following the curing, the abrasion resistance is measured and compared with an uncoated control. It was found that these hybrid organic/inorganic networks partially afford excellent abrasion resistance to the polycarbonate substrates investigated. In addition to having excellent abrasion resistance comparable to current commercial coatings, some newly developed systems are also UV resistant. Similar coating formulations applied to metals can greatly improve the abrasion resistance despite the fact that the coatings are lower in density than their substrates.

Wen, J.; Jordens, K.; Wilkes, G.L. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States)

1996-12-31

308

Synergistic effects of micro-abrasion–corrosion of UNS S30403, S31603 and S32760 stainless steels  

Microsoft Academic Search

In this study, the synergistic effects of abrasion and corrosion on UNS S30403, S31603 and S32760 stainless steels have been investigated using a micro-abrasion test rig. The stainless steel samples have been studied under both pure abrasion (PA) and abrasion–corrosion (AC) conditions simulated by using silicon carbide based slurries in either distilled water or 3.5% sodium chloride solutions. Tests have

J. O. Bello; R. J. K. Wood; J. A. Wharton

2007-01-01

309

Aspects of blast resistant masonry design  

SciTech Connect

Blast resistant design should be examined for building code incorporation, due to the potential of explosions occurring in an industrial society. Specifically, public and commercial structures of concrete masonry construction need additional building code criteria, since these buildings have high density populations to protect. Presently, blast resistant design is accomplished by using government published manuals, but these do not address industry standard construction. A design air blast load of 4.54 kg (10 lbs) of TNT, located 0.91 m (3 ft) above ground surface and 30.48 m (100 ft) from a structure should be considered standard criteria. This loading would be sufficient to protect against blast, resist progressive failure, and yet not be an economic impediment. Design details and adequate inspection must be observed to ensure blast resistant integrity. 10 refs., 3 figs., 1 tab.

Volkman, D.E.

1989-01-01

310

Quantifying the significance of abrasion and selective transport for downstream fluvial grain size evolution  

NASA Astrophysics Data System (ADS)

It is well known that pebble diameter systematically decreases downstream in rivers. The contribution of abrasion is uncertain, in part because (1) diameter is insufficient to characterize pebble mass loss due to abrasion and (2) abrasion rates measured in laboratory experiments cannot be easily extrapolated to the field. A recent geometric theory describes abrasion as a curvature-dependent process that produces a two-phase evolution: in Phase I, initially blocky pebbles round to smooth, convex shapes with little reduction in axis dimensions; then, in Phase II, smooth, convex pebbles slowly reduce their axis dimensions. Here we provide strong evidence that two-phase abrasion occurs in a natural setting, by examining downstream evolution of shape and size of thousands of pebbles over ~10 km in a tropical montane stream. The geometric theory is verified in this river system using a variety of manual and image-based shape parameters, providing a generalizable method for quantifying the significance of abrasion. Phase I occurs over ~1 km, in upstream bedrock reaches where abrasion is dominant and sediment storage is limited. In downstream alluvial reaches, where Phase II occurs, we observe the expected exponential decline in pebble diameter. Using a discretized abrasion model (the so-called "box equations") with deposition, we deduce that abrasion removes more than one third of the mass of a pebble but that size-selective sorting dominates downstream changes in pebble diameter. Overall, abrasion is the dominant process in the downstream diminution of pebble mass (but not diameter) in the studied river, with important implications for pebble mobility and the production of fine sediments.

Miller, Kimberly Litwin; Szabó, Tímea; Jerolmack, Douglas J.; Domokos, Gábor

2014-11-01

311

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

SciTech Connect

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

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

2010-03-15

312

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

313

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 daytime float conditions. Each 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

314

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 daytime float conditions. Each 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.

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

2006-01-01

315

Proc. CMP-MIC, pp. 395-402, Santa Clara, CA, March 2001. A Fixed Abrasive CMP Model  

E-print Network

the use of a fixed abrasive CMP pad [1], in which abrasive material is embedded into the polishing padProc. CMP-MIC, pp. 395-402, Santa Clara, CA, March 2001. A Fixed Abrasive CMP Model Brian Lee mechanical polishing (CMP) has emerged as the planarization technique of choice in both front-end (STI

Boning, Duane S.

316

29 CFR 1926.909 - Firing the blast.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Firing the blast. 1926.909 Section 1926.909 Labor...Explosives § 1926.909 Firing the blast. (a) A code of blasting signals...at suitable locations. (b) Before a blast is fired, a loud warning signal...

2010-07-01

317

30 CFR 816.64 - Use of explosives: Blasting schedule.  

Code of Federal Regulations, 2010 CFR

...periods for blasting. (3) Unscheduled blasts may be conducted only where public or...When an operator conducts an unscheduled blast, the operator, using audible signals...document the reason for the unscheduled blast in accordance with § 816.68(p)....

2010-07-01

318

Chronic traumatic encephalopathy in blast-exposed military veterans and a blast neurotrauma mouse model.  

PubMed

Blast exposure is associated with traumatic brain injury (TBI), neuropsychiatric symptoms, and long-term cognitive disability. We examined a case series of postmortem brains from U.S. military veterans exposed to blast and/or concussive injury. We found evidence of chronic traumatic encephalopathy (CTE), a tau protein-linked neurodegenerative disease, that was similar to the CTE neuropathology observed in young amateur American football players and a professional wrestler with histories of concussive injuries. We developed a blast neurotrauma mouse model that recapitulated CTE-linked neuropathology in wild-type C57BL/6 mice 2 weeks after exposure to a single blast. Blast-exposed mice demonstrated phosphorylated tauopathy, myelinated axonopathy, microvasculopathy, chronic neuroinflammation, and neurodegeneration in the absence of macroscopic tissue damage or hemorrhage. Blast exposure induced persistent hippocampal-dependent learning and memory deficits that persisted for at least 1 month and correlated with impaired axonal conduction and defective activity-dependent long-term potentiation of synaptic transmission. Intracerebral pressure recordings demonstrated that shock waves traversed the mouse brain with minimal change and without thoracic contributions. Kinematic analysis revealed blast-induced head oscillation at accelerations sufficient to cause brain injury. Head immobilization during blast exposure prevented blast-induced learning and memory deficits. The contribution of blast wind to injurious head acceleration may be a primary injury mechanism leading to blast-related TBI and CTE. These results identify common pathogenic determinants leading to CTE in blast-exposed military veterans and head-injured athletes and additionally provide mechanistic evidence linking blast exposure to persistent impairments in neurophysiological function, learning, and memory. PMID:22593173

Goldstein, Lee E; Fisher, Andrew M; Tagge, Chad A; Zhang, Xiao-Lei; Velisek, Libor; Sullivan, John A; Upreti, Chirag; Kracht, Jonathan M; Ericsson, Maria; Wojnarowicz, Mark W; Goletiani, Cezar J; Maglakelidze, Giorgi M; Casey, Noel; Moncaster, Juliet A; Minaeva, Olga; Moir, Robert D; Nowinski, Christopher J; Stern, Robert A; Cantu, Robert C; Geiling, James; Blusztajn, Jan K; Wolozin, Benjamin L; Ikezu, Tsuneya; Stein, Thor D; Budson, Andrew E; Kowall, Neil W; Chargin, David; Sharon, Andre; Saman, Sudad; Hall, Garth F; Moss, William C; Cleveland, Robin O; Tanzi, Rudolph E; Stanton, Patric K; McKee, Ann C

2012-05-16

319

Chronic Traumatic Encephalopathy in Blast-Exposed Military Veterans and a Blast Neurotrauma Mouse Model  

PubMed Central

Blast exposure is associated with traumatic brain injury (TBI), neuropsychiatric symptoms, and long-term cognitive disability. We examined a case series of postmortem brains from U.S. military veterans exposed to blast and/or concussive injury. We found evidence of chronic traumatic encephalopathy (CTE), a tau protein–linked neurodegenerative disease, that was similar to the CTE neuropathology observed in young amateur American football players and a professional wrestler with histories of concussive injuries. We developed a blast neurotrauma mouse model that recapitulated CTE-linked neuropathology in wild-type C57BL/6 mice 2 weeks after exposure to a single blast. Blast-exposed mice demonstrated phosphorylated tauopathy, myelinated axonopathy, microvasculopathy, chronic neuroinflammation, and neurodegeneration in the absence of macroscopic tissue damage or hemorrhage. Blast exposure induced persistent hippocampal-dependent learning and memory deficits that persisted for at least 1 month and correlated with impaired axonal conduction and defective activity-dependent long-term potentiation of synaptic transmission. Intracerebral pressure recordings demonstrated that shock waves traversed the mouse brain with minimal change and without thoracic contributions. Kinematic analysis revealed blast-induced head oscillation at accelerations sufficient to cause brain injury. Head immobilization during blast exposure prevented blast-induced learning and memory deficits. The contribution of blast wind to injurious head acceleration may be a primary injury mechanism leading to blast-related TBI and CTE. These results identify common pathogenic determinants leading to CTE in blast-exposed military veterans and head-injured athletes and additionally provide mechanistic evidence linking blast exposure to persistent impairments in neurophysiological function, learning, and memory. PMID:22593173

Goldstein, Lee E.; Fisher, Andrew M.; Tagge, Chad A.; Zhang, Xiao-Lei; Velisek, Libor; Sullivan, John A.; Upreti, Chirag; Kracht, Jonathan M.; Ericsson, Maria; Wojnarowicz, Mark W.; Goletiani, Cezar J.; Maglakelidze, Giorgi M.; Casey, Noel; Moncaster, Juliet A.; Minaeva, Olga; Moir, Robert D.; Nowinski, Christopher J.; Stern, Robert A.; Cantu, Robert C.; Geiling, James; Blusztajn, Jan K.; Wolozin, Benjamin L.; Ikezu, Tsuneya; Stein, Thor D.; Budson, Andrew E.; Kowall, Neil W.; Chargin, David; Sharon, Andre; Saman, Sudad; Hall, Garth F.; Moss, William C.; Cleveland, Robin O.; Tanzi, Rudolph E.; Stanton, Patric K.; McKee, Ann C.

2013-01-01

320

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

321

Wire blade development for Fixed Abrasive Slicing Technique (FAST) slicing  

NASA Technical Reports Server (NTRS)

A low cost, effective slicing method is essential to make ingot technology viable for photovoltaics in terrestrial applications. The fixed abrasive slicing technique (FAST) combines the advantages of the three commercially developed techniques. In its development stage FAST demonstrated cutting effectiveness of 10 cm and 15 cm diameter workpieces. Wire blade development is still the critical element for commercialization of FAST technology. Both impregnated and electroplated wire blades have been developed; techniques have been developed to fix diamonds only in the cutting edge of the wire. Electroplated wires show the most near term promise and this approach is emphasized. With plated wires it has been possible to control the size and shape of the electroplating, it is expected that this feature reduces kerf and prolongs the life of the wirepack.

Khattak, C. P.; Schmid, F.; Smith, M. B.

1982-01-01

322

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

323

Wear model simulating clinical abrasion on composite filling materials.  

PubMed

The aim of this study was to establish a wear model for testing composite filling materials with abrasion properties closer to a clinical situation. In addition, the model was used to evaluate the effect of filler volume and particle size on surface roughness and wear resistance. Each incisor tooth was prepared with nine identical standardized cavities with respect to depth, diameter, and angle. Generic composite of 3 different filler volumes and 3 different particle sizes held together with the same resin were randomly filled in respective cavities. A multidirectional wet-grinder with molar cusps as antagonist wore the surface of the incisors containing the composite fillings in a bath of human saliva at a constant temperature of 37°C. The present study suggests that the most wear resistant filling materials should consist of medium filling content (75%) and that particles size is not as critical as earlier reported. PMID:21946496

Johnsen, Gaute Floer; Taxt-Lamolle, Sébastien F; Haugen, Hĺvard J

2011-01-01

324

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

325

Investigation of atmospheric blasts by fast radiometry  

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

326

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

327

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

SciTech Connect

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

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

2009-01-01

328

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

329

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

330

Microstructural effects in abrasive wear. Third annual progress report, August 12, 1983-August 14, 1984  

SciTech Connect

The two major goals of the project are to improve our understanding of the mechanisms of carbide removal and of the role of matrix properties in abrasion. In the area of carbide removal mechanisms, progress this year has included completion of the fixed-depth scratch test apparatus and its use to demonstrate the occurrence of gross carbide cracking under fixed-depth conditions; comparable cracking does not occur under fixed-load conditions at a similar mean load. A high-stress abrasion system has been constructed and tested which will facilitate studies of abrasion under conditions similar to those produced by the fixed-depth scratch test system. Analysis of the work on the size effect in abrasion of dual-phase alloys has been completed. The largest single item in this year's proposed work in a study of the abrasion resistance and mechanisms of material removal in model alloys having second-phase particles (SPP's) with varying fracture properties. In the area of the effects of matrix properties on abrasion, the majority of the effort this year has centered on transmission electron microscopy of the subsurface deformation microstructures developed during abrasion.

Kosel, T.H.

1984-08-14

331

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

332

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

333

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

334

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

335

Process for the manufacture of a steel body with a borehole protected against abrasion  

SciTech Connect

A process for providing abrasion and corrosion resistance in the borehole of a steel body comprising placing an alloying material of solid form within the borehole of the steel body, the alloying material having abrasion and corrosion resistance, and thereafter melting the alloying material in a gas heated protective gas oven to effect diffusion bonding of the alloying material with the steel body and the formation of an abrasion and corrosion resistant lining on the steel body. The borehole is of non-circular shape in cross-section and, particularly, of figure 8 shape.

Gnadig, G.; Przybylla, F.; Schneider, F.

1985-02-05

336

Radiation-curable abrasion-resistant coating based on pentaerythritol and trimethylolpropane triacrylates  

SciTech Connect

The use of copolymers of pentaerythritol triacrylate and trimethylolpropane triacrylate, respectively, with various acrylic or vinyl monomers in radiation curing for the preparation of abrasion-resistant coatings was studied. Pentaerythritol triacylate systems exhibited higher viscosities, faster photoresponse and better abrasion-resistance than the equivalent trimethylolpropane triacrylate systems. Among the comonomers evaluated, pentaerythritol triacrylate/N-vinyl pyrrolidone at a weight ratio of 80/20 exhibited the best performance. The cured films exhibited better abrasion-resistance, optical clarity, and lower shrinkage (curling) than that prepared from the pentaerythritol triacrylate homopolymer.

Tu, R.S.

1983-01-01

337

Effect of the Blasting Angle on Blast Processing of a Cylindrical Surface  

NASA Astrophysics Data System (ADS)

Blast processing is a substrate processing technique during which spherical or granular materials are jetted against the substrate surface using compressed air. Blasting techniques is widely used for various mechanical parts as a surface reforming technique. When performing blast processing to a complicated-shaped substrate for the purpose of thermal spraying method, it is difficult to set blasting angle to a constant value and it is necessary to clarify the effect of state of substrate on blast processing. In present paper, the effect of blasting angle to removal processing effect and the modification state of substrate is investigated. Results from this investigation are summarized as follows: When blasting angle ? was 30ş, the removal quantity ? showed the maximum. The removal quantity became large as cylindrical diameter D was larger. Removal quantity of particle diameter a =100 ?m is bigger than that of a =700 ?m. As a nozzle movement rate v increased, removal quantity ? became small. As blasting angle ? became small, removal quantity ? became large even though nozzle movement rate v was changed. As blasting pressure P increases, removal quantity ? became big.

Kubohori, Toshifumi; Binti Khalil, Nur Zalikha; Tojo, Yuichi; Takahashi, Shigetaka

338

Cygnus Loop Supernova Blast Wave  

NASA Technical Reports Server (NTRS)

This is an image of a small portion of the Cygnus Loop supernova remnant, which marks the edge of a bubble-like, expanding blast wave from a colossal stellar explosion, occurring about 15,000 years ago. The HST image shows the structure behind the shock waves, allowing astronomers for the first time to directly compare the actual structure of the shock with theoretical model calculations. Besides supernova remnants, these shock models are important in understanding a wide range of astrophysical phenomena, from winds in newly-formed stars to cataclysmic stellar outbursts. The supernova blast is slamming into tenuous clouds of insterstellar gas. This collision heats and compresses the gas, causing it to glow. The shock thus acts as a searchlight revealing the structure of the interstellar medium. The detailed HST image shows the blast wave overrunning dense clumps of gas, which despite HST's high resolution, cannot be resolved. This means that the clumps of gas must be small enough to fit inside our solar system, making them relatively small structures by interstellar standards. A bluish ribbon of light stretching left to right across the picture might be a knot of gas ejected by the supernova; this interstellar 'bullet' traveling over three million miles per hour (5 million kilometres) is just catching up with the shock front, which has slowed down by ploughing into interstellar material. The Cygnus Loop appears as a faint ring of glowing gases about three degrees across (six times the diameter of the full Moon), located in the northern constellation, Cygnus the Swan. The supernova remnant is within the plane of our Milky Way galaxy and is 2,600 light-years away. The photo is a combination of separate images taken in three colors, oxygen atoms (blue) emit light at temperatures of 30,000 to 60,000 degrees Celsius (50,000 to 100,000 degrees Farenheit). Hydrogen atoms (green) arise throughout the region of shocked gas. Sulfur atoms (red) form when the gas cools to around 10,000 degrees Celsius (18,000 degrees Farenheit).

1993-01-01

339

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

340

Material Systems for Blast-Energy Dissipation  

SciTech Connect

Lightweight panels have been designed to protect buildings and vehicles from blast pressures by activating energy dissipation mechanisms under the influence of blast loading. Panels were fabricated which featured a variety of granular materials and hydraulic dissipative deformation mechanisms and the test articles were subjected to full-scale blast loading. The force time-histories transmitted by each technology were measured by a novel method that utilized inexpensive custom-designed force sensors. The array of tests revealed that granular materials can effectively dissipate blast energy if they are employed in a way that they easily crush and rearrange. Similarly, hydraulic dissipation can effectively dissipate energy if the panel features a high fraction of porosity and the panel encasement features low compressive stiffness.

James Schondel; Henry S. Chu

2010-10-01

341

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

342

Localized coating removal using plastic media blasting  

NASA Technical Reports Server (NTRS)

Steps taken to qualify the use of plastic media blasting for safely and effectively removing paint and other coatings from solid rocket booster aluminum structures are described. As a result of the effort, an improvement was made in the design of surface finishing equipment for processing flight hardware, in addition to a potentially patentable idea on improved plastic media composition. The general arrangement of the blast equipment and the nozzle configuration are presented.

Novak, Howard L.; Wyckoff, Michael G.; Zook, Lee M.

1988-01-01

343

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

344

Space shuttle holddown post blast shield  

NASA Technical Reports Server (NTRS)

The original and subsequent designs of the Solid Rocket Booster/Holddown Post blast shield assemblies and their associated hardware are described. It presents the major problems encountered during their early use in the Space Shuttle Program, during the Return-to-Flight Modification Phase, and during their fabrication and validation testing phases. The actions taken to correct the problems are discussed, along with the various concepts now being considered to increase the useful life of the blast shield.

Larracas, F. B.

1991-01-01

345

Rice Blast Genomics: K12 Outreach  

NSDL National Science Digital Library

This outreach component of the Rice Blast Project provides online genomics activities for high-school students. A lab manual is also offered free of charge to teachers of high-school biology in North Carolina, Texas, Kentucky, Arizona, Virginia, and Indiana. The Rice Blast Project is a collaboration of scientists from North Carolina State University, Texas A&M University, University of Kentucky, University of Arizona, Purdue University, Ohio State University, and Virginia Bioinformatics Institute.

346

Lightweight Energy Absorbers for Blast Containers  

NASA Technical Reports Server (NTRS)

Kinetic-energy-absorbing liners made of aluminum foam have been developed to replace solid lead liners in blast containers on the aft skirt of the solid rocket booster of the space shuttle. The blast containers are used to safely trap the debris from small explosions that are initiated at liftoff to sever frangible nuts on hold-down studs that secure the spacecraft to a mobile launch platform until liftoff.

Balles, Donald L.; Ingram, Thomas M.; Novak, Howard L.; Schricker, Albert F.

2003-01-01

347

Computational Modeling and Optimization of a Novel Shock Tube to Study Blast Induced Traumatic Brain Injury  

E-print Network

Over the last decade, soldiers fighting in Iraq and Afghanistan are being exposed to blasts from powerful explosives with improvised detonation techniques. These blasts put them at high risk of closed head non-impact Blast-induced Traumatic Blast...

Anumolu, Pratima

2014-08-06

348

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

NASA Astrophysics Data System (ADS)

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

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

2008-03-01

349

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

NASA Astrophysics Data System (ADS)

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

Wang, Jing; Zhu, Yaofeng; Fu, Yaqin

2013-11-01

350

The effect on cast post dimensions of casting investment and airborne particle abrasion.  

PubMed

Cast posts can sometimes prove difficult to seat fully during fitting. This study compared two different liquid/water dilutions for phosphate bonded investment and the effect of controlled airborne particle abrasion on resulting post diameter. After measuring polymeric post patterns (n = 18), 3 groups were invested using concentrated solution and 3 groups using dilute solution. After casting they were weighed and remeasured then exposed to airborne particle abrasion. Both solutions produced oversized cast posts. Mean diameter reduction during airborne particle abrasion was 8 microm/10s taking an average of 41s to reach precast size. Where a post pattern fits tightly, airborne particle abrasion for 70s should reduce the casting sufficiently to accommodate the cement lute. PMID:22645794

Hashem, Danya; German, Matthew J; Wassell, Robert W

2011-09-01

351

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

PubMed Central

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

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

2012-01-01

352

Development and characterization of a high abrasion resistant alumina-zirconia composite material  

SciTech Connect

The addition of zirconia to alumina has been a subject of interest for quite a long time for many researchers. The sand abrasion of these composite materials, however, has rarely been discussed in the literature. this paper reports the preparation of two different types of alumina-zirconia composites by adding either m-zirconia or t-zirconia, in different amounts, to the alumina matrix and the study of their various properties. The sand abrasion resistance test was carried out following the ASTM G-65 standard. The abrasion-resistant behavior shown by this test is correlated with the other properties of the as-prepared alumina-zirconia composites. This paper presents a high abrasion resistant alumina-zirconia composite material.

Satapathy, L.N.

1999-06-01

353

A high-performance, abrasion-resistant, scaling-resistant material  

SciTech Connect

Contrast tests of abrasion by ejection of pulverized coal between a novel visco-elastic material ultra-high molecular weight polyethylene and other materials as well as industrial test of ash piping in the site of a thermal power plant were carried out. The results showed that the performance of the former against abrasion and impact is excellent, the mechanism of its abrasion resistance is unique, it possesses good property of scaling resistance and has thus a valuable perspective in development and application as an anti-abrasion and anti-scaling material. A composite pipe lined with such a material has obtained a Chinese Patent, and a small scale pilot production is now under way.

Wang Zhengxiong

1999-07-01

354

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

355

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

356

Methods for predicting rubble motion during blasting  

SciTech Connect

Recent applications of explosives and blasting agents to rubble rock have led to requirements for more elaborate design and analysis methods. Many in situ extraction techniques require rubblization to take place in a confined region where rock motion is a predominate factor in creating a permeable broken bed. Two analytical methods are presented which describe the large rubble motion during blasting. These methods are intended to provide the blast designer with a tool for evaluation and further refinement of blasting patterns and timing sequences. In both these methods, the rock medium is represented by a series of discrete, discontinuous regions (bodies, masses). The use of discontinuous techniques rather than the classical continuum methods, results in better approximations to the rubble motion. These regions are set in motion by pressure loads from the explosive. The motion of these regions is then calculated numerically using interaction laws between regions in contact. The basis for these models or methods is presented along with the background for selecting explosive pressure loads and rock mass material behavior. Typical examples, including both cratering and bench blasting geometries, are discussed which illustrate the use of these models to predict rubble motion. Such engineering representations appear to provide a practical method for use in predicting rubble motion and a tool for design evaluation of blasting in confined geometries.

Schamaun, J.T.

1984-03-01

357

Effect of canopy leaf distribution on sand transport and abrasion energy  

NASA Astrophysics Data System (ADS)

During times when crop canopies are short or sparse, wind erosion can uncover plant roots, deplete the soil resource, and damage plants by abrasion and desiccation. Few studies have considered the effects of position and number of leaves on sand transport and the distribution of the sand abrasion energy. The objectives of this study were to determine the effects of number and distribution of leaves on threshold velocities, sand transport rates, and relative abrasion energy among simulated dicotyledonous plant canopies. Six canopies were tested in a wind tunnel with two levels of leaf area index (LAI), two different maximum leaf heights, and either two or four leaves per plant with maximum freestream wind speeds from 12 to 17 m s-1. The leaf heights were selected to position the lowest leaves to be either intercepting saltating sand or largely above the saltation layer. The wind tunnel was a 1.52 W × 1.82 H × 15.3 L m push-type recirculating tunnel with the floor covered with a layer of sieved sand. Sand discharge and relative abrasion energy were measured during 3-min duration test runs. For canopies with two leaves, the experimental sand transport capacity was reduced most when the leaves were highest above the surface even though they were intercepting saltation when in their lowest positions. As expected, canopy LAI was directly related to threshold velocity and inversely related to sand transport capacity. Total abrasion energy impacting the target soil channel containers located vertically in the canopy increased with wind speeds above the threshold. Within canopies, high wind speeds increased height of maximum abrasion but often still caused less total abrasion per unit sand discharge than over a bare, sandy surface. When leaves were located nearest the surface, they modified the vertical abrasion profiles by deflecting a portion of the sand impact energy upward in the wind stream. Overall, the canopies modified both the profiles and normalized abrasion energy of the sand discharge when compared with a bare, sandy surface. Hence, it may be important to place test plants within a canopy of similar plants—to allow development of a fully developed velocity profile in the canopy by using a minimum upwind fetch of about 70 canopy heights in a wind tunnel—when conducting plant abrasion tests using sand to achieve results representative of plants in the interior of a field. In contrast, abrasion on inter-row flat soil containers was independent of wind speeds, but was higher without a canopy compared with measurements in the canopy for a given sand discharge.

Hagen, L. J.; Casada, M. E.

2013-09-01

358

Structural Surface of Mould Softness Abrasive Flow Precision Polishing Machining Method Based on VOF  

Microsoft Academic Search

Aiming to improve the surface roughness of precision mould structural surface in finish machining, a new mould structural surface no-tool precision polishing method based on softness abrasive flow was brought forward. Dynamical model of softness abrasive flow in bound flow oriented to mould structural surface precision machining was established based on liquid-solid two-phase flow coupling theory and a continuous media

Bo Tang; Shiming Ji; Dapeng Tan

2010-01-01

359

MAGNETIC FIELD ANALYSIS AND ROUGHNESS PREDICTION IN MAGNETORHEOLOGICAL ABRASIVE HONING (MRAH)  

Microsoft Academic Search

Magnetorheological Abrasive Honing (MRAH) is a recently developed process to finish engineering surfaces. The process makes use of a magnetically stiffened abrasive-mixed magnetorheological fluid as the flexible tool and rotation-cum-reciprocation movements between the finishing medium and the workpiece surface for providing finishing action. In the present work, a finite element analysis with Mechanical\\/Emag module of ANSYS is performed to understand

A. Sadiq; M. S. Shunmugam

2009-01-01

360

The abrasive corrosion behavior of plasma-nitrided alloy steels in chloride environments  

Microsoft Academic Search

Both corrosion and abrasive corrosion behavior of plama-nitrided type 304 and 410 stainless steels and 4140 low alloy steel were investigated in 3% NaCl solution (pH = 6.8) by electrochemical corrosion measurements. Surface morphology and alloying elements after corrosion and abrasion corrosion tests were examined by scanning electron microscopy and energy dispersive analysis of X-rays. The results indicated that the

C. K. Lee; H. C. Shih

2000-01-01

361

A Material Removal Model for CMP Based on the Contact Mechanics of Pad, Abrasives, and Wafer  

Microsoft Academic Search

Applied pressure in chemical mechanical polishing CMP is shared by the two-body pad-wafer and the three-body pad-abrasive- wafer contacts. The fraction of applied pressure transferred through the particle contacts is a significant factor as most of the material removal is due to abrasive particles trapped in the pad-wafer interface. In this work, the contact of a rough, deformable pad and

Dinc?er Bozkaya; Sinan Mu?ftu?

2009-01-01

362

Finishing effect of abrasive flow machining on micro slit fabricated by wire-EDM  

Microsoft Academic Search

This experimental research use the method of abrasive flow machining (AFM) to evaluate the characteristics of various levels\\u000a of roughness and finishing of the complex shaped micro slits fabricated by wire electrical discharge machining (Wire-EDM).\\u000a An investigative methodology based on the Taguchi experimental method for the micro slits of biomedicine was developed to\\u000a determine the parameters of AFM, including abrasive

Hsinn-Jyh Tzeng; Biing-Hwa Yan; Rong-Tzong Hsu; Han-Ming Chow

2007-01-01

363

Effects of particle size and structure of carbon blacks on the abrasion of filled elastomer compounds  

Microsoft Academic Search

The effects of the particle size and structure of various carbon blacks on friction and abrasion behavior of filled natural\\u000a rubber (NR), styrene–butadiene rubber (SBR) and polybutadiene (BR) compounds were investigated using a modified blade abrader.\\u000a The effect of particle size and structure on abrasion resistance should be considered for the optimum design of desired wear\\u000a properties. Characteristic parameters were

Chang Kook Hong; Hyunsung Kim; Changseok Ryu; Changwoon Nah; Yang-Il Huh; Shinyoung Kaang

2007-01-01

364

In vitro toothbrush-dentifrice abrasion of resin-modified glass ionomers  

Microsoft Academic Search

Objectives. This study was conducted to compare the rate of abrasive wear and change in surface roughness of resin-modified and conventional acid-base glass ionomers when subjected to toothbrush-dentifrice abrasion.Methods. Two resin-modified and two conventional glass ionomers were used. Samples of a high-copper amalgam and a hybrid resin composite were used as reference materials. Specimens of each material were prepared and

Yasuko Momoi; Kunitsugu Hirosaki; Atsushi Kohno; John F. McCabe

1997-01-01

365

The effect of heat treatment on the abrasion resistance of alloy white irons  

Microsoft Academic Search

The effect of the temperature and time of the destabilization and sub-critical heat treatments on the abrasive wear behaviour of two high-chromium white iron alloys (15-3 Cr?Mo and 27 Cr) was investigated. The response of each alloy to the destabilization heat treatment and, therefore, the microstructures developed, differed significantly. Pin abrasion tests were conducted, and showed the wear resistance of

C. P. Tabrett; I. R. Sare

1997-01-01

366

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

367

Bending and abrasion fatigue of common suture materials used in arthroscopic and open orthopedic surgery.  

PubMed

In orthopedic surgery, the reattachment of tendon to bone requires suture materials that have stable and durable properties to allow time for healing at the tendon-bone interface. The suture, not rigidly restrained within the anchor eyelet, is free to move during surgery and potentially after surgery with limb motion. During such movement, the suture is subjected to bending and frictional forces that can lead to fatigue-induced failure. We investigated some common contemporary commercial number-two-grade suture materials and evaluated their resistance to bending abrasion fatigue and the consequent failure. Sutures were oscillated over a stainless steel wire at low frequency under load. Number of abrasion cycles to failure, changes in suture morphology, and fatigue-failure method was recorded for each material. Suture structure had a significant effect on abrasion resistance, with braided sutures containing large numbers of fine high tenacity core filaments performing 15-20 times better than other braided suture structures. Ultra high molecular weight polyethylene (UHMWPE) core filaments resisted bending abrasion failure better than other core materials due to the load spreading and abrasion resistance of these filaments. Sutures with UHMWPE cores also had high resistance to tensile failure. Limited correlation was observed between tensile strength and abrasion resistance. PMID:22777625

Savage, Earle; Hurren, Christopher J; Slader, Simon; Khan, Lukman A K; Sutti, Alessandra; Page, Richard S

2013-01-01

368

Age-related mandible abrasion in the groundhopper Tetrix tenuicornis (Tetrigidae, Orthoptera).  

PubMed

A study was conducted to determine whether the mandibles of the detrito-/bryophagous groundhopper Tetrix tenuicornis are subject to mechanical wear as a result of feeding, as is the case for grasshoppers that feed on silica-rich grasses. Abrasion was evaluated by measuring the length and width of the 3rd incisor and length of the 4th incisor in adults of different ages collected under natural conditions during one season. Although T. tenuicornis and other groundhoppers avoid feeding on grasses, we found that mandible abrasion increased with T. tenuicornis age. Age-related abrasion of the incisors of left and right mandibles was statistically significant in both sexes but the degree of abrasion was greater for females than males, apparently reflecting differences in the frequency and magnitude of feeding. Degree of abrasion also differed between right and left mandibles, probably because of differences in how each mandible is used during food processing. Abrasion of cuticular mandible structures may reduce the effectiveness of food processing late in the season. PMID:24583696

Ku?avová, Kate?ina; Hajduková, Lenka; Ko?árek, Petr

2014-05-01

369

An energetic approach to abrasive wear of a martensitic stainless steel  

SciTech Connect

Abrasive wear is the most common type of wear that causes failure of machine elements. Examinations of abraded surfaces revealed presence of embedded particles and grooves elongated along the sliding direction. This indicates that, there are two sequential stages of an abrasion process. In the first stage, asperities on the hard surface and/or hard abrasive grains penetrate into the soft material surface and then in the second stage, they grind the surface in the sliding direction. Therefore, indentation and scratching of an indenter, which can be realized by hardness and scratch tests, can simulate the damage produced on the abraded surface. On the basis of this simulation, an energetic model is proposed for abrasive wear in the present study. In this study, abrasive wear behavior of a martensitic stainless steel is examined by hardness and scratch tests. The results of tests were evaluated to estimate the work done during abrasion and to find out the dimensional wear coefficient according to the model proposed above.

Pamuk, U.; Baydogan, M.; Niluefer, B.; Cimenoglu, H.

2000-04-01

370

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

371

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

372

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

373

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

374

Alkahest NuclearBLAST : a user-friendly BLAST management and analysis system  

PubMed Central

Background - Sequencing of EST and BAC end datasets is no longer limited to large research groups. Drops in per-base pricing have made high throughput sequencing accessible to individual investigators. However, there are few options available which provide a free and user-friendly solution to the BLAST result storage and data mining needs of biologists. Results - Here we describe NuclearBLAST, a batch BLAST analysis, storage and management system designed for the biologist. It is a wrapper for NCBI BLAST which provides a user-friendly web interface which includes a request wizard and the ability to view and mine the results. All BLAST results are stored in a MySQL database which allows for more advanced data-mining through supplied command-line utilities or direct database access. NuclearBLAST can be installed on a single machine or clustered amongst a number of machines to improve analysis throughput. NuclearBLAST provides a platform which eases data-mining of multiple BLAST results. With the supplied scripts, the program can export data into a spreadsheet-friendly format, automatically assign Gene Ontology terms to sequences and provide bi-directional best hits between two datasets. Users with SQL experience can use the database to ask even more complex questions and extract any subset of data they require. Conclusion - This tool provides a user-friendly interface for requesting, viewing and mining of BLAST results which makes the management and data-mining of large sets of BLAST analyses tractable to biologists. PMID:15958161

Diener, Stephen E; Houfek, Thomas D; Kalat, Sam E; Windham, DE; Burke, Mark; Opperman, Charles; Dean, Ralph A

2005-01-01

375

Evaluation of the incidence of gingival abrasion as a result of toothbrushing.  

PubMed

The aims of the present study were: (1) to establish the incidence of gingival abrasion as a result of toothbrushing, using a manual and electric toothbrush; (2) to establish the influence of filament end-rounding on the incidence of gingival abrasion and the efficacy of toothbrushing; (3) to assess whether the speed of the electric brush has a feedback-effect on the brushing force used and to correlate the incidence of gingival abrasion with force. 2 experiments were carried out. In the first experiment, 50 subjects brushed for 3 weeks every other day with either a manual (Butler 411) or an electric toothbrush (Braun/Oral-B Ultra Plaque Remover-D9). All received brief instructions and were asked to abstain from oral hygiene 24 hrs before their appointment. After disclosing the teeth and gums with Mira-2-Tone solution, plaque and gingival abrasion were assessed. Next, the panelists brushed in a random split-mouth order. After brushing and a second disclosing, plaque and abrasion were re-assessed. The results showed that the incidence of gingival abrasion was comparable for the manual and the D9. Using a similar design as in experiment no. 1, in experiment no. 2 a new group of 47 subjects brushed for 3 weeks alternating between the Braun/Oral-B Plaque Remover-D7 and D9. At the appointment, the subjects first brushed in a split-mouth order with the D9 with 2 different types of endrounding. Plaque and abrasion were assessed. Immediately following this brushing exercise, the subjects re-brushed with the D7 (2800 rot/min) and the D9 (3600 rot/min) during which brushing force was measured. The results of this experiment showed that endrounding has no effect on plaque removal but does effect the incidence of gingival abrasion. Brushing force is not influenced by the speed of the brushhead and no correlation with the incidence of gingival abrasion was observed. In conclusion, the results of this study show that gingival abrasion is not influenced by brushing force, but is affected by filament endrounding. PMID:9763324

Danser, M M; Timmerman, M F; IJzerman, Y; Bulthuis, H; van der Velden, U; van der Weijden, G A

1998-09-01

376

Mechanics of the pad-abrasive-wafer contact in chemical mechanical polishing  

NASA Astrophysics Data System (ADS)

In chemical mechanical polishing (CMP), a rigid wafer is forced on a rough, elastomeric polishing pad, while a slurry containing abrasive particles flows through the interface. The applied pressure on the wafer is carried partially by the 2-body pad-wafer contact (direct contact) and partially by the 3-body contact of pad, wafer and abrasive particles ( particle contact). The fraction of the applied pressure carried by particle contacts is an important factor affecting the material removal rate (MRR) as the majority of the material is removed by the abrasive particles trapped between the pad asperities and the wafer. In this thesis, the contact of a rough, deformable pad and a smooth, rigid wafer in the presence of rigid abrasive particles at the contact interface is investigated by using contact mechanics and finite element (FE) modeling. The interactions between the pad, the wafer and the abrasive particles are modeled at different scales of contact, starting from particle level interactions, and gradually expanding the contact scale to the multi-asperity contact of pad and wafer. The effect of surface forces consisting of van der Waals and electrical double layer forces acting between the wafer and the abrasive particles are also investigated in this work. The wear rate due to each abrasive particle is calculated based on the wafer-abrasive particle contact force, and by considering adhesive and abrasive wear mechanisms. A passivated layer on the wafer surface with a hardness and thickness determined by the chemical effects is modeled, in order to characterize the effect of chemical reactions between slurry and wafer on the MRR. The model provides accurate predictions for the MRR as a function of pad related parameters; pad elastic modulus, pad porosity and pad topography, particle related parameters; particle size and concentration, and slurry related parameters; slurry pH, thickness and hardness of the passivated surface layer of wafer. A good qualitative agreement between the model and the experiments is found for the variation of the MRR with respect to these parameters. Furthermore, closed form equations are derived in order to optimize the CMP parameters for maximizing the material removal efficiency, which is a measure of the ability of pad to transmit the applied pressure on the abrasive particles. The optimization of the CMP parameters described in this thesis may be particularly important for the low-pressure CMP of ultra-low-k (ULK) dielectric materials, where it is difficult to achieve acceptable MRR without compromising the porous structure of ULK materials.

Bozkaya, Dincer

2009-12-01

377

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

378

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

379

30 CFR 75.1310 - Explosives and blasting equipment.  

Code of Federal Regulations, 2011 CFR

...blasting units shall be taken or used underground. (b) Black blasting powder, aluminum-cased detonators, aluminum-alloy-cased detonators, detonators with aluminum leg wires, and safety fuses shall not be taken or used...

2011-07-01

380

30 CFR 57.20031 - Blasting underground in hazardous areas.  

Code of Federal Regulations, 2010 CFR

...false Blasting underground in hazardous areas. 57.20031 Section 57.20031 ...20031 Blasting underground in hazardous areas. In underground areas where dangerous accumulations of water, gas, mud, or fire atmosphere could be...

2010-07-01

381

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

382

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

383

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

384

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

385

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

386

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

387

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

388

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

389

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

390

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

391

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

392

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

393

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

394

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

395

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

396

Modelling human eye under blast loading.  

PubMed

Primary blast injury (PBI) is the general term that refers to injuries resulting from the mere interaction of a blast wave with the body. Although few instances of primary ocular blast injury, without a concomitant secondary blast injury from debris, are documented, some experimental studies demonstrate its occurrence. In order to investigate PBI to the eye, a finite element model of the human eye using simple constitutive models was developed. The material parameters were calibrated by a multi-objective optimisation performed on available eye impact test data. The behaviour of the human eye and the dynamics of mechanisms occurring under PBI loading conditions were modelled. For the generation of the blast waves, different combinations of explosive (trinitrotoluene) mass charge and distance from the eye were analysed. An interpretation of the resulting pressure, based on the propagation and reflection of the waves inside the eye bulb and orbit, is proposed. The peculiar geometry of the bony orbit (similar to a frustum cone) can induce a resonance cavity effect and generate a pressure standing wave potentially hurtful for eye tissues. PMID:23521031

Esposito, L; Clemente, C; Bonora, N; Rossi, T

2015-01-01

397

Theoretical Concept to Understand Plan and Design Smooth Blasting Pattern  

Microsoft Academic Search

Considering different mechanical cutting tools for excavation of rock, drilling and blasting is said to be inexpensive and\\u000a at the same time most acceptable and compatible to any geo-excavation condition. Depending upon strength properties of in-situ\\u000a rock mass, characteristics of joint pattern and required quality of blasting, control blasting techniques viz., pre-split\\u000a and smooth blasting are commonly implemented to achieve

S. K. Mandal; M. M. Singh; S. Dasgupta

2008-01-01

398

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

399

30 CFR 75.1320 - Multiple-shot blasting.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false Multiple-shot blasting. 75.1320...and Blasting § 75.1320 Multiple-shot blasting. (a...round shall be initiated in sequence from the opener hole or holes...round shall be initiated in sequence from the opener hole or...

2010-07-01

400

BLAST FURNACE CAST HOUSE EMISSION CONTROL TECHNOLOGY ASSESSMENT  

EPA Science Inventory

The study describes the state-of-the-art of controlling fumes escaping from blast furnace cast houses. Background information is based on: a study of existing literature; visits to blast furnaces in the U.S., Japan, and Europe; meetings with an ad hoc group of experienced blast f...

401

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...

402

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

403

Isothermal blast wave model of supernova remnants  

NASA Technical Reports Server (NTRS)

The validity of the 'adiabatic' assumption in supernova-remnant calculations is examined, and the alternative extreme of an isothermal blast wave is explored. It is concluded that, because of thermal conductivity, the large temperature gradients predicted by the adiabatic model probably are not maintained in nature. Self-similar solutions to the hydrodynamic equations for an isothermal blast wave have been found and studied. These solutions are then used to determine the relationship between X-ray observations and inferred parameters of supernova remnants. A comparison of the present results with those for the adiabatic model indicates differences which are less than present observational uncertainties. It is concluded that most parameters of supernova remnants inferred from X-ray measurements are relatively insensitive to the specifics of the blast-wave model.

Solinger, A.; Buff, J.; Rappaport, S.

1975-01-01

404

Computation of blast wave-obstacle interactions  

NASA Technical Reports Server (NTRS)

Numerical simulations of the interaction of a planar blast wave with various obstacles are presented. These obstacles are either ground structures or vehicles flying in the atmosphere. For a structure on the ground, the blast wave encounter is side-on, while for the flying vehicles the encounter is either head-on or oblique. Second-order accurate, finite-difference, and shock-capturing procedures are employed to solve the two-dimensional, axisymmetric, and three-dimensional unsteady Euler equations. Results are presented for the flow field consisting of blast wave striking obstacles that are at rest, moving subsonically and moving supersonically. Comparison of the numerical results with experimental data for a configuration at rest substantiates the validity of this approach and its potential as a flow analysis tool.

Champney, J. M.; Chaussee, D. S.; Kutler, P.

1982-01-01

405

Comparative Evaluation of Gingival Depigmentation using Tetrafluoroethane Cryosurgery and Gingival Abrasion Technique: Two Years Follow Up  

PubMed Central

Objective: A comparative evaluation of the gingival depigmentation by using Tetrafluoroethane cryosurgery and the gingival abrasion technique – 2 years of follow up. Material and Methods: Ten systemically healthy patients who were aged 18 to 36 years were selected for the study. Tetrafluoroethane was used for the cryosurgical depigmentation and the gingival abrasion technique used a coarse flame shaped bur. The presence or absence of pigmentation was tabulated, based on the GPI (Gingival Pigmentation Index). For the statistical analysis, Freidman’s test was used. Results: The keratinization was completed within a week after the application of the cryogen and about 10 days after the gingival abrasion technique was done. The statistical analysis which was done after 90th, 180th days and 2 years. The p-value which was obtained (p<.001) showed the superiority of cryosurgery over the gingival abrasion. During the follow up period, no side effects were seen for both the techniques and the improved aesthetics was maintained upto 2 years. Conclusion: The use of cryogen Tetrafluoroethane is easy, practical and inexpensive as compared to gingival abrasion, due to its high rate of recurrence. Hence, it is more acceptable to the patients and the operator. Further studies are needed to assess the long term effectiveness of the cryosurgical method of depigmentation. PMID:23543863

Kumar, Santhosh; Bhat, G. Subraya; Bhat, K. Mahalinga

2013-01-01

406

Studies of the degradation of metal-adhesive interfaces with surface analysis techniques  

NASA Astrophysics Data System (ADS)

The application of bonded repairs and reinforcements to aircraft components places an emphasis on adherend surface treatment procedures because these treatments can significantly change bond strength and durability. A typical minimum treatment sequence for Alclad 2024-T3 aluminium alloy adherends includes a solvent degrease, an abrasion with a Scotchbrite ® pad, a clean with a methyl-ethyl-ketone (MEK) soaked tissue and a grit-blast with 45 ?m alumina powder. The adherends are treated with ?-glycidoxy-propyl-trimethoxy-silane (?-GPTS) coupling agent then bonded with an epoxy film adhesive. The composition of the adherent, the bond durability and the locus of fracture were examined at several stages of the adherent surface treatment. Boeing wedge tests show that grit-blasting the adherends creates a more durable adhesive bond than the Scotchbrite ®/MEK treatment and that the application of ?-GPTS improves bond durability in both cases. XPS has shown that the cleaning sequence decreases the concentration of hydrocarbon contaminant on the grit-blasted adherend to an average thickness of less than 1.5 nm. XPS analyses of the fracture surfaces indicates that for the grit-blast, grit-blast plus ?-GPTS and Scotchbrite ®/MEK plus ?-GPTS treatments, failure occurs primarily in the oxide film, whereas for the Scotchbrite ®/MEK treatment failure occurs at the adhesive/oxide interface possibly due to weakness induced by contaminant. XPS measurements show that a ?-GPTS overlayer retards the growth of the oxide on aluminium in humid air, until the ?-GPTS overlayer is desorbed. The improved bond durability with the coupling agent may be due to the inhibition of hydration sites on this oxide surface.

Arnott, D. R.; Wilson, A. R.; Rider, A. N.; Lambrianidis, L. T.; Farr, N. G.

1993-06-01

407

Increase in the productivity of blast-furnace stoves  

SciTech Connect

The Novolipetsk combine proposed sending a cold blast through a special 150-mm-diameter pipe passing through an igniter opening into the combustion chamber. To evaluate the efficiency the stove performance in which some of the cold blast was directed to the combustion chamber was compared against that of unmodified stoves. This blast-delivery system was found to increase consumption of blast-furnace gas during the first stage, reduce time required to bring the dome up to prescribed temperatures, shorten the stove-heating period, and increase blast-heating temperature by 10-15/degree/.

Solomentsev, S.L.; Chernobrivets, B.F.; Sigmund, V.K.; Basukinskii, S.M.; Beremblyum, G.B.; Nakhaev, P.E.; Serpevskii, S.L.

1988-03-01

408

Evaluation of subsurface damage in GaN substrate induced by mechanical polishing with diamond abrasives  

NASA Astrophysics Data System (ADS)

The relationship between the depth of the subsurface damage (SSD) and the size of the diamond abrasive used for mechanical polishing (MP) of GaN substrates was investigated in detail. GaN is categorized as a hard, brittle material, and material removal in MP proceeds principally to the fracture of GaN crystals. Atomic force microscopy and cathodoluminescence imaging revealed that the mechanical processing generated surface scratches and SSD. The SSD depth reduced as the diamond abrasive size reduced. A comparison of the relationship between the SSD depth and the diamond abrasive size used in the MP of GaN with the same relationship for typical brittle materials such as glass substrates suggests that the MP of GaN substrates proceeds via the same mechanism as glass.

Aida, Hideo; Takeda, Hidetoshi; Kim, Seong-Woo; Aota, Natsuko; Koyama, Koji; Yamazaki, Tsutomu; Doi, Toshiro

2014-02-01

409

Abrasion-ablation model for neutron production in heavy ion reactions  

NASA Technical Reports Server (NTRS)

In heavy ion reactions, neutron production at forward angles is observed to occur with a Gaussian shape that is centered near the beam energy and extends to energies well above that of the beam. This paper presents an abrasion-ablation model for making quantitative predictions of the neutron spectrum. To describe neutrons produced from the abrasion step of the reaction where the projectile and target overlap, the authors use the Glauber model and include effects of final-state interactions. They then use the prefragment mass distribution from abrasion with a statistical evaporation model to estimate the neutron spectrum resulting from ablation. Measurements of neutron production from Ne and Nb beams are compared with calculations, and good agreement is found.

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

1995-01-01

410

Evaluation of oxide-chemical mechanical polishing characteristics using ceria-mixed abrasive slurry  

NASA Astrophysics Data System (ADS)

Chemical-mechanical polishing (CMP) characteristics of mixed abrasive slurry (MAS) were studied which was retreated by adding of Ceria (CeO2) abrasives within 1:10 diluted silica slurry (DSS). The slurry was designed for optimal performance which produces reasonable removal rate, acceptable polishing selectivity with respect to underlying layer, low surface defects after polishing, and good slurry stability. The modified abrasives in MAS are evaluated with respect to their particle size distribution, surface morphology, and CMP performances such as removal rate and non-uniformity. As an experimental result, we could obtain successful slurry characteristics compared with traditional silica slurry in the viewpoint of removal rate and non-uniformity.

Lee, Youngkyun; Seo, Yong-Jin; Jeong, Haedo

2012-10-01

411

Inhibitors for organic phosphonic acid system abrasive free polishing of Cu  

NASA Astrophysics Data System (ADS)

Organic phosphonic acid system abrasive free slurry for copper polishing is developed in our earlier work. Since material removal rate is too high to be applied as precision polishing slurry for copper, inhibitors are needed. Experiment results also show us that the most commonly used inhibitor benzotriazole is unsuitable for this abrasive free slurry, and then another kind of compound inhibitors for this organic phosphonic acid system abrasive free slurry are developed. The compound inhibitors, consisting of ascorbic acid and ethylene thiourea, can control the material removal rate and also reduce surface roughness. XPS results show that, in the compound inhibitors, ascorbic acid participates in the surface chemical reaction, forms passivating layer on copper surface and helps to control the material removal rate. Corrosion current calculated from polarization curve is consistent with material removal rate. Ethylene thiourea contributes to the reduction of surface roughness, which can be indicated by the peak shape change of S 2p in XPS results.

Wei, Zhang; Xinchun, Lu; Yuhong, Liu; Guoshun, Pan; Jianbin, Luo

2009-01-01

412

Powder processing and abrasion resistance of in-situ iron matrix-TiC-reinforced composites  

SciTech Connect

Reactive powder processing techniques were used to produce TiC reinforced ferrous matrix composites. Mixture of elemental Fe, Cr, Ti and graphite powders were hot-pressed to full density. During heating a Self-propagating High-temperature Synthesis (SHS)-type reaction initiated at about 1150°C and transformed the Ti, Cr and graphite powders to TiC and (Fe,Cr)x,Cy in an steel (Fe-Cr-C) matrix. This reaction occurred only in those mixtures containing Ti powder (i.e., no such reaction was detected in mixtures of Fe, Cr and graphite powders). The resultant hot-pressed microstructures consisted of uniformly dispersed and large carbide particles in a steel matrix, and ideal microstructure for abrasion resistance. The abrasion resistance of the composites were evaluated by pin-abrasion testing and the results compared favorable to traditional wear resistant materials, such as cast iron.

Dogan, Omer N.; Alman, David E.; Hawk, Jeffrey A.

2000-10-01

413

The design, implementation, and evaluation of mpiBLAST  

SciTech Connect

mpiBLAST is an open-source parallelization of BLAST that achieves superlinear speed-up by segmenting a BLAST database and then having each node in a computational cluster search a unique portion of the database. Database segmentation permits each node to search a smaller portion of the database, eliminating disk I/O and vastly improving BLAST performance. Because database segmentation does not create heavy communication demands, BLAST users can take advantage of low-cost and efficient Linux cluster architectures such as the bladed Beowulf. In addition to presenting the software architecture of mpiBLAST we present a detailed performance analysis of mpiBLAST to demonstrate its scalability.

Darling, A. E. (Aaron E.); Carey, L. (Lucas); Feng, W. C. (Wu-Chun)

2003-01-01

414

Nineteen-Foot Diameter Explosively Driven Blast Simulator  

SciTech Connect

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 tunnel length is 305 feet. The development of this 19-foot diameter blast tunnel is presented. The small scale research test results using 4 inch by 8 inch diameter and 2 foot by 6 foot diameter shock tube facilities are included. Analytically predicted parameters are compared to experimentally measured blast tunnel parameters in this report. The blast tunnel parameters include distance, time, static, overpressure, stagnation pressure, dynamic pressure, reflected pressure, shock Mach number, flow Mach number, shock velocity, flow velocity, impulse, flow duration, etc. Shadowgraphs of the shock wave are included for the three different size blast tunnels.

VIGIL,MANUEL G.

2001-07-01

415

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

416

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 badly 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, and shares the results and conclusions of the testing.

Mitchell, Kathryn C.

2010-01-01

417

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

418

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

419

Platelet Recruitment Promotes Keratocyte Repopulation following Corneal Epithelial Abrasion in the Mouse  

PubMed Central

Corneal abrasion not only damages the epithelium but also induces stromal keratocyte death at the site of injury. While a coordinated cascade of inflammatory cell recruitment facilitates epithelial restoration, it is unclear if this cascade is necessary for keratocyte recovery. Since platelet and neutrophil (PMN) recruitment after corneal abrasion is beneficial to epithelial wound healing, we wanted to determine if these cells play a role in regulating keratocyte repopulation after epithelial abrasion. A 2 mm diameter central epithelial region was removed from the corneas of C57BL/6 wildtype (WT), P-selectin deficient (P-sel-/-), and CD18 hypomorphic (CD18hypo) mice using the Algerbrush II. Corneas were studied at 6h intervals out to 48h post-injury to evaluate platelet and PMN cell numbers; additional corneas were studied at 1, 4, 14, and 28 days post injury to evaluate keratocyte numbers. In WT mice, epithelial abrasion induced a loss of anterior central keratocytes and keratocyte recovery was rapid and incomplete, reaching ~70% of uninjured baseline values by 4 days post-injury but no further improvement at 28 days post-injury. Consistent with a beneficial role for platelets and PMNs in wound healing, keratocyte recovery was significantly depressed at 4 days post-injury (~30% of uninjured baseline) in P-sel-/- mice, which are known to have impaired platelet and PMN recruitment after corneal abrasion. Passive transfer of platelets from WT, but not P-sel-/-, into P-sel-/- mice prior to injury restored anterior central keratocyte numbers at 4 days post-injury to P-sel-/- uninjured baseline levels. While PMN infiltration in injured CD18hypo mice was similar to injured WT mice, platelet recruitment was markedly decreased and anterior central keratocyte recovery was significantly reduced (~50% of baseline) at 4–28 days post-injury. Collectively, the data suggest platelets and platelet P-selectin are critical for efficient keratocyte recovery after corneal epithelial abrasion. PMID:25775402

Landry, Paul; Magadi, Sri; Smith, C. Wayne; Rumbaut, Rolando E.; Burns, Alan R.

2015-01-01

420

[Evaluation of potential risks of abrasive water jet osteotomy in-vivo].  

PubMed

Since the 80's the water jet scalpel is an established tool in some surgical fields. It is used in particular in visceral surgery for preparation of parenchymatous organs. By the addition of biocompatible abrasives, this technique is able to effectively machine hard biological tissues. Free defined cutting geometries can be realised in a non contact process. Therewith this method has crucial advantages compared to conventional osteotomy techniques and gives new impulses to the development in endoprosthetics and correction osteotomies of hollow bones. In the presented work the new developed abrasive water injection jet (AWIJ) was used the first time for in-vivo osteotomies. Aim of this study was the detection of potential thrombembolic effects and wash in effects of the cutting fluid. Hollow bones of the fore and hind leg of 20 house pigs were treated with the new cutting technique. Intraoperative documentation of relevant vital parameters was performed by a multi monitoring system. Thrombembolic effects during the osteotomy were detected by transthoracic Doppler ultrasonography and transesophagale echocardiography. The hollow bones were prepared in consideration of the vascularisation's protection especially in respect to the venous flow. Thrombembolic effects with temporary haemodynamic respectively respiratory consequences could be detected exclusively by using the so called "3-component jet", which consists of 90 vol % of air. The usage of an abrasive suspension enables the airfree dosing of dry soluable abrasives. Thrombembolic effects could not be monitored in this case. Intramedullary fluid in-wash effects as well as resulting electrolytic disorders could not be proven. For abrasive waterjet osteotomies with 3 component jet a relevant risk of thrombembolic effects could be shown. This knowledge has also to be considered for abdominal and neurosurgical applications in the future. Due to the usage of an abrasive suspension this risk can fully be avoided. PMID:16300049

Kuhlmann, C; Pude, F; Bishup, C; Krömer, S; Kirsch, L; Andreae, A; Wacker, K; Schmolke, S

2005-10-01

421

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...

422

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

423

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...

424

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

425

NK cells are necessary for recovery of corneal CD11c+ dendritic cells after epithelial abrasion injury  

Technology Transfer Automated Retrieval System (TEKTRAN)

Mechanisms controlling CD11c(+) MHCII(+) DCs during corneal epithelial wound healing were investigated in a murine model of corneal abrasion. Selective depletion of NKp46(+) CD3- NK cells that normally migrate into the cornea after epithelial abrasion resulted in >85% reduction of the epithelial CD1...

426

Department of Mechanical and Nuclear Engineering Fall 2011 Torque and Axial Measurement Device for Soil Abrasion Testing  

E-print Network

PENNSTATE Department of Mechanical and Nuclear Engineering Fall 2011 Torque and Axial Measurement Device for Soil Abrasion Testing Overview The Penn State Department of Energy and Mineral Engineering instrument they are using to develop a soil abrasion index. While our team's initially proposed concept met

Demirel, Melik C.

427

A study of abrasion–corrosion of AISI 304L austenitic stainless steel in saline solution using acoustic emission technique  

Microsoft Academic Search

In industrial environment, many materials are subjected to the abrasion–corrosion phenomenon. In such cases, stainless steels are often used for their good corrosion resistance. However, the synergistic effect between abrasion and corrosion may be a serious contributor to the total wear even when pure corrosion rates do not appear to be significant. In order to select the more resistant alloy

F Ferrer; H Idrissi; H Mazille; P Fleischmann; P Labeeuw

2000-01-01

428

Clark, William Isaac. Fixed-Abrasive Diamond Wire Saw Machining. (Under the direction of Dr. Albert Shih)  

E-print Network

saw machining with wood and foam ceramic materials. Fixed abrasive diamond wire saw machining for pine and oak wood materials. Finally, an experiment was designed to machine three types of foam ceramic of Dr. Albert Shih) The goal of this research was to investigate the use of fixed abrasive diamond wire

Shih, Albert J.

429

Contact Model for a Pad Asperity and a Wafer Surface in the Presence of Abrasive Particles for Chemical Mechanical Polishing  

E-print Network

April 9-13, 2007. In CMP the interface of the polishing-pad and the wafer is filled with liquid slurryContact Model for a Pad Asperity and a Wafer Surface in the Presence of Abrasive Particles and abrasive particles. The average surface roughness Ra of the pad is much larger than the typical particle

MĂĽftĂĽ, Sinan

430

Lee, et al., "A Fixed Abrasive CMP Model" CMP-MIC Conference March 20011 Brian Lee, Duane S. Boning  

E-print Network

height *Smith, "A CMP Model Combining Density and Time Dependencies," CMP-MIC 1999. Pad Dielectric Film Pad Dielectric Film #12;Lee, et al., "A Fixed Abrasive CMP Model" CMP-MIC Conference ­ March 20018Lee, et al., "A Fixed Abrasive CMP Model" CMP-MIC Conference ­ March 20011 Brian Lee, Duane S

Boning, Duane S.

431

Patterns in Blast Injuries to the Hand  

PubMed Central

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

Buntic, Rudolf F.; Brooks, Darrell

2008-01-01

432

Comparison of dry wear characteristics of two abrasion-resistant steels: Q/T C1095 and 15B37H  

SciTech Connect

The dry reciprocating wear characteristics of two abrasion-resistant steels, C1095 and 15B37H, against an abrasive material were studied. Results showed that abrasive wear and surface fatigue were the primary wear mechanisms. The wear failure of the steels was related to frictional softening during wear.

Sim, G.; Tandon, K.N. [Univ. of Manitoba, Winnipeg (Canada). Dept. of Mechanical and Industrial Engineering; Iqbal, K. [Manitoba Rolling Mills, Selkirk, Manitoba (Canada); Wang, Y. [Beijing Univ. of Aeronautics and Astronautics (China)

1995-10-01

433

ICAM-1 mediates surface contact between neutrophils and keratocytes following corneal epithelial abrasion in the mouse  

Technology Transfer Automated Retrieval System (TEKTRAN)

Corneal epithelial abrasion elicits an inflammatory response involving neutrophil (PMN) recruitment from the limbal vessels into the corneal stroma. These migrating PMNs make surface contact with collagen and stromal keratocytes. Using mice deficient in PMN integrin CD18, we previously showed that P...

434

Microstructural Changes of Human Enamel Surfaces by Brushing with and without Dentifrice Containing Abrasive  

Microsoft Academic Search

Toothbrushing with and without dentifrice containing abrasive was performed on human enamel pieces attached to resin plates exposed to the oral cavities of 3 human subjects for 8 weeks. The effects on the ground enamel surfaces with engraved scratches were examined by scanning electron and scanning laser microscopy. Brushing with such a dentifrice caused smaller scratches to disappear, large scratches

M. Kuroiwa; T. Kodaka

1993-01-01

435

Surface finish on hardened bearing steel parts produced by superhard and abrasive tools  

Microsoft Academic Search

New technological process consisting of hard turning (HT) followed by abrasive machining, in place of the widely used method in industry, i.e., hard turning versus grinding, has lately been launched in the automotive industry. This is because, many transmissions parts, such as synchronizing gears, crankshafts and camshafts require superior surface finish along with appropriate fatigue performance. This paper provides a

W. Grzesik; J. Rech; T. Wanat

2007-01-01

436

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...

437

Relationship of abrasive wear resistance to the physicomechanical properties of materials  

Microsoft Academic Search

Conclusions 1.The abrasive wear resistance of metals is related linearally to the deformation component of the work of friction multiplied by the ratio of hardness to the coefficient of friction in wear.2.To reveal a single relationship of the wear resistance of polymers and metals with the cohesive energy it is necessary to multiply the latter by hardness and divide by

A. I. Lavrent'ev

1978-01-01

438

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...

439

Antiadhesive effects of Budesonide combined with spraygel in a cecal abrasion model: an experimental study  

Microsoft Academic Search

Many methods have been described for preventing or reducing postoperative adhesions. In this work, we evaluated the effectiveness of Budesonide in combination with SprayGel in a reducing postoperative adhesion in rats as the model. Cecal abrasion was achieved in 60 male Sprague-Dawley rats, by brushing and by applying 70% alcohol. The rats were separated into six groups and treated with

M. Tahir Ozer; Onder Onguru; Ayse Eken; Huseyin Sinan; Kagan Coskun; Emin Ozgur Akgul; Nurkan Torer; Mehmet Eryilmaz; Sezai Demirbas; A. Ihsan Uzar

2012-01-01

440

Tribological properties of amorphous alloys and the role of surfaces in abrasive wear of materials  

NASA Technical Reports Server (NTRS)

The research approach undertaken by the authors relative to the subject, and examples of results from the authors are reviewed. The studies include programs in adhesion, friction, and various wear mechanisms (adhesive and abrasive wear). The materials which have been studied include such ceramic and metallic materials as silicon carbide, ferrites, diamond, and amorphous alloys.

Miyoshi, K.; Buckley, D. H.

1982-01-01

441

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

442

Influence of orientation and volume fraction of Aramid fabric on abrasive wear performance of polyethersulfone composites  

Microsoft Academic Search

In case of fabric reinforced composites of specialty polymers influence of orientation of fabric and its volume fraction on tribo-behaviour is sparingly studied. In our earlier work, we have reported on the influence of amount of Aramid fabric (AF) in polyethersulfone (PES) on abrasive wear performance. However, orientation effect of fabric with respect to abrading plane was not investigated. In

J. Bijwe; S. Awtade; A. Ghosh

2006-01-01

443

Influence of Concentration of Aramid Fabric on Abrasive Wear Performance of Polyethersulfone Composites  

Microsoft Academic Search

In this work, three composites of polyethersulfone (PES) containing Aramid (Kevlar 29) fabric with concentration 64, 72 and 83% (by weight) were developed by the compression molding technique. These composites were characterized for their mechanical and physical properties. The abrasive-wear performance of the composites was evaluated by abrading 1 × 1 × 1 cm3 samples against silicon carbide paper under

J. Bijwe; S. Awtade; B. K. Satapathy; A. Ghosh

2004-01-01

444

Abrasive Wear Behaviour of COPPER-SiC and COPPER-SiO2 Composites  

NASA Astrophysics Data System (ADS)

The present paper reports abrasive wear behaviour of copper matrix composites reinforced with silicon carbide and silica particles. Copper - SiC (12%) and Copper-SiO2 (9%) composites were prepared by powder metallurgical technique. Metallography, image analysis and hardness studies were carried out on copper composites. The abrasive wear experiments were carried out using pin on disc apparatus. The effect of sliding distance and load was studied on Copper - SiC (12%) and Copper-SiO2 (9%) composites. The abrasive wear volume loss increased with sliding distance in both the composites although the magnitude of increase was different in each case. Copper - SiC (12%) composites exhibited relatively better abrasion resistance as compared to and Copper-SiO2 (9%) composites. The abraded surfaces were observed under scanning electron microscope to study the morphology of abraded surfaces and operating wear mechanism. The analysis of wear debris particles was also carried out to substantiate the findings of the investigation.

Umale, Tejas; Singh, Amarjit; Reddy, Y.; Khatitrkar, R. K.; Sapate, S. G.

445

Abrasion Resistance Of High-idensity Polyethylene Jackets Useid On Submarine Cables  

Microsoft Academic Search

polyethylene jackets used on submarine electro-optical cables abrade and wear. The mechanisms involved in this process are complex, and current theories of abrasion and wear of polymers are not reliable for predicting wear rates and jaclket lifetimes. The Applied Physics Laboratory at the University of Washington is con- ducting experiments to quantify wear rates on high-density polyethylene (HDPE) cable jackets.

K. G. Booth; C. J. Sandwith

1992-01-01

446

Dental casting alloys behaviour during power toothbrushing with toothpastes with various abrasivities. Part I: wear behavior.  

PubMed

The purpose of this study was to evaluate the long term effect of abrasivity of toothpastes normally used over the surface and mechanical properties of dental casting alloys. Three dental casting alloys (Ni-Cr, Co-Cr, c.p. Ti) and one ceramic were chosen. Four specimens of each material were immersed in artificial saliva, brushed without or with one of four toothpastes of different Relative Dentine Abrasivity (RDA 50, 52, 80, and 114). An electric toothbrush with a load of 250 g was used for 420 min. Mass loss was determined by difference in weight, microhardness and surface roughness were also measured. Two-way ANOVA and non-parametric tests were used to detect significant differences. Titanium specimens (478 microg/cm(2)) exhibited the most mass loss, whereas ceramic (282 microg/cm(2)) and Co-Cr (262 microg/cm(2)) exhibited the least. However, ceramic demonstrated the most volume loss (0.239 mm(3)). The abrasivity effect of the toothpaste correlated with the RDA values. Slight variations in microhardness were observed after toothbrushing and depended on the material but not on the toothpaste used. Material surfaces were slightly smoothed by toothbrushing but no significant differences were detected. Dental casting alloys and ceramic are susceptible to abrasion by brushing with an electric toothbrush depending on the RDA value of the toothpaste. Variations in microhardness and surface roughness were not clinically relevant. PMID:18389345

Nogués, Ll; Martinez-Gomis, J; Molina, C; Peraire, M; Salsench, J; Sevilla, P; Gil, F J

2008-09-01

447

Maintenance and preservation of concrete structures. Report 3: Abrasion-erosion resistance of concrete  

NASA Astrophysics Data System (ADS)

This report describes a laboratory test program on abrasion-erosion resistance of concrete, including the development of a new underwater abrasion-erosion test method. This program was designed to evaluate the relative abrasion-erosion resistance of various materials considered for use in the repair of erosion-damaged concrete structures. The test program encompassed three concrete types (conventional concrete, fiber-reinforced concrete, and polymer concrete); seven aggregate types (limestone, chert, trap rock, quartzite, granite, siliceous gravel, and slag); three principal water-cement rations (0.72, 0.54, and 0.40); and six types of surface treatment (vacuum, polyurethane coating, acrylic mortar coating, epoxy mortar coating, furan resin mortar coating, and iron aggregate topping). A total of 114 specimens made from 41 batches of concrete was tested. Based on the test data obtained, a comprehensive evaluation of the effects of various parameters on the abrasion-erosion resistance of concrete was presented. Materials suitable for use in the repair of erosion-damaged concrete structures were recommended. Additional work to correlate the reported findings with field performance was formulated.

Liu, T. C.

1980-07-01

448

Friction and abrasion resistance of cast aluminum alloy-fly ash composites  

SciTech Connect

The abrasive wear properties of stir-cast A356 aluminum alloy-5 vol pct fly ash composite were tested against hard SiC{sub p} abrasive paper and compared to those of the A356 base alloy. The results indicate that the abrasive wear resistance of aluminum-fly ash composite is similar to that of aluminum-alumina fiber composite and is superior to that of the matrix alloy for low loads up to 8 N (transition load) on a pin. At loads greater than 8 N, the wear resistance of aluminum-fly ash composite is reduced by debonding and fracture of fly ash particles. Microscopic examination of the worn surfaces, wear debris, and subsurface shows that the base alloy wears primarily by microcutting, but the composite wears by microcutting and delamination caused by crack propagation below the rubbing surface through interfaces between fly ash and silicon particles and the matrix. The decreasing specific wear rates and friction during abrasion wear with increasing load have been attributed to the accumulation of wear debris in the spaces between the abrading particles, resulting in reduced effective depth of penetration and eventually changing the mechanism from two-body to three-body wear, which is further indicated by the magnitude of wear coefficient.

Rohatgi, P.K.; Guo, R.Q.; Huang, P. [Univ. of Wisconsin, Milwaukee, WI (United States). Dept. of Materials; Ray, S. [Univ. of Roorkee (India). Dept. of Metallurgical Engineering

1997-01-01

449

Abrasive wear behavior of heat-treated ABC-silicon carbide  

SciTech Connect

Hot-pressed silicon carbide, containing aluminum, boron, and carbon additives (ABC-SiC), was subjected to three-body and two-body wear testing using diamond abrasives over a range of sizes. In general, the wear resistance of ABC-SiC, with suitable heat treatment, was superior to that of commercial SiC.

Zhang, Xiao Feng; Lee, Gun Y.; Chen, Da; Ritchie, Robert O.; De Jonghe, Lutgard C.

2002-06-17

450

NK cells modulate the inflammatory response to corneal epithelial abrasion and thereby support wound healing  

Technology Transfer Automated Retrieval System (TEKTRAN)

Natural killer cells are lymphocytes of the innate immune system that have crucial cytotoxic and regulatory roles in adaptive immunity and inflammation. Herein, we consider a role for these cells in corneal wound healing. After a 2-mm central epithelial abrasion of the mouse cornea, a subset of clas...

451

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

452

An integrated testing method for cermet abrasion resistance and fracture toughness evaluation  

Microsoft Academic Search

Two main sources of failure, abrasive wear and brittle fracture, lead to massive losses of function in mining equipment involving high maintenance costs as well as replacement costs and extended downtime for worn or malfunctioning equipment and tools. In the industrial processes involving for e.g. direct impact and rubbing contact between the mining tools and rock, the main question remains

S. F. Sciezka; K. Filipowicz

1998-01-01

453

Two-body abrasive wear of Al–SiC composites  

Microsoft Academic Search

The two-body abrasive wear behaviour of aluminium matrix composites reinforced with silicon carbide particles has been investigated. The metal matrix composites were fabricated by a powder metallurgy route involving a final hot extrusion step, with Al 1100 matrix and ?-SiCp reinforcement with mean sizes of 10, 27 and 43 ?m, in the proportions of 5, 10 and 20 vol.%. Using

Kassim S Al-Rubaie; Humberto N Yoshimura; José Daniel Biasoli de Mello

1999-01-01

454

Correlating microstructural features and mechanical properties with abrasion resistance of a high strength low alloy steel  

Microsoft Academic Search

A study towards the examination of the abrasive wear behaviour and other characteristics, viz. microstructure, tensile properties and hardness of a high strength low alloy steel has been carried out in order to establish a correlation amongst the parameters and to optimize the microstructural features and mechanical properties for superior wear performance. The steel was subjected to various heat treatment

A. K. Jha; B. K. Prasad; O. P. Modi; S. Das; A. H. Yegneswaran

2003-01-01

455

Laser sintering (SLS) of hard metal powders for abrasion resistant coatings  

Microsoft Academic Search

Selective laser sintering (SLS), one of the new RP, RT and RM techniques, may be able to provide a process to form hard coating, which increases the life of machine parts in abrasive conditions. It is known that cemented carbide (WC–Co) parts can be made by this technology, although not to full density. A porous shell of WC–Co, shaped to

K Maeda; T. H. C Childs

2004-01-01

456

Abrasion resistance of magnesium alloys with surface films generated from phosphonate imidazolium ionic liquids  

NASA Astrophysics Data System (ADS)

Surface films formed by treatment with the ionic liquids (ILs) 1,3-dimethylimidazolium methylphosphonate (LMP101), 1-ethyl-3-methylimidazolium methylphosphonate (LMP102) and 1-ethyl-3-methylimidazolium ethylphosphonate (LEP102) on magnesium alloys have been studied. The abrasion resistance of the coated alloys was studied by microscratching under progressively increasing load, and compared with that of the uncoated materials. Abrasion-protective phosphorus-containing films are generated on AZ31B, with an order of abrasion resistance as a function of the IL of LEP102 > LMP101 > LMP102, with a reduction in penetration depth of a 67% for the sample treated with LEP102 with respect to the uncovered alloy. This is attributed to the formation of a continuous adhered phosphorus-containing film. In contrast, the abrasion resistance of EZ33A alloy is not improved due to the presence of the less reactive Zn-rich phase at the grain boundaries, which prevents the formation of a continuous protective layer. The results are discussed from contact angles, SEM-EDX and XPS analysis.

Espinosa, T.; Jiménez, A. E.; Martínez-Nicolás, G.; Sanes, J.; Bermúdez, M. D.

2014-11-01

457

Abrasion resistance of the columnar zone in high Cr white cast irons  

Microsoft Academic Search

High chromium white cast irons are extremely abrasion resistant materials due primarily to their high carbide content. In the columnar zone of cast structures, eutectic carbides grow parallel to the direction of heat flow, forming a highly anisotropic morphology. In this US Bureau of Mines investigation, specimens taken from the columnar zone of these castings were tested utilizing a pin

Ö. N. Do?an; G. Laird II; J. A. Hawk

1995-01-01

458

Hot direct extrusion—A novel method to produce abrasion-resistant metal-matrix composites  

Microsoft Academic Search

This paper discusses hot direct extrusion as a novel method to produce rods made of a metal-matrix composite (MMC). Due to the excellent abrasive wear resistance of hard phase and iron-base metal powder blends, hot direct extrusion is a highly promising method of producing long cylindrical products. This production process combines sintering of the capsuled powder mixtures at high temperatures

Werner Theisen; Markus Karlsohn

2007-01-01

459

Abrasion resistance of high nodule count ductile iron with different matrix microstructures  

Microsoft Academic Search

Thin wall ductile iron is being used in the industry as a way to improve the strength to weight ratio. Nevertheless, thin walled sections promote microstructural changes such as an important increase in the nodule count. This paper examines the influence of the nodule count on the abrasion resistance of ductile iron castings, having different matrix microstructures, and analyzes the

R. C. Dommarco; M. E. Sousa; J. A. Sikora

2004-01-01

460

Effect of filler porosity on the abrasion resistance of nanoporous silica gel\\/polymer composites  

Microsoft Academic Search

Objectives. This laboratory study was designed to investigate the effect of controlled nanoporosity on the wear resistance of polymeric composites reinforced with silica gel powders and to determine the mechanisms controlling the abrasive wear properties of these unique nanostructured materials.Methods. Silica gels were prepared by hydrolysis and condensation of tetraethylorthosilicate (TEOS) using four different catalysts to modify the porous structure

Jiazhong Luo; John J. Lannutti; Robert R. Seghi

1998-01-01

461

Influence of Acidified Fluoride Gel on Abrasion Resistance of Eroded Enamel  

Microsoft Academic Search

The objective of the study was to evaluate the abrasion resistance of eroded enamel brushed with an acidified fluoride gel. Each enamel specimen was prepared from one of 64 bovine incisors. The specimens were embedded in acrylic resin, ground flat, polished and subsequently covered with a tape exposing an area of 1.8×10.0 mm in the center of the enamel specimens.

T. Attin; H. Deifuss; E. Hellwig

1999-01-01

462

Comparison of the clinical abrasion resistance of six commercially available denture teeth  

Microsoft Academic Search

Purpose. Clinical abrasion of denture teeth has certain implications when dentures are worn in excess of the average useful lifetime. The purpose of this study was to evaluate clinical denture tooth wear over a period of 3 years.Material and Methods. The wear of six commercially available denture teeth (Premierdent, Acrotone, Vitapan, Rx1, Duravite, and Ivoclar Orthosit) and a seventh combination

Con Jooste; Greta Geerts; Laurie Adams

1997-01-01

463

30 CFR 56.6200 - Delivery to storage or blast site areas.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Delivery to storage or blast site areas. 56.6200 Section 56... § 56.6200 Delivery to storage or blast site areas. Explosive material shall...without undue delay to the storage area or blast...

2010-07-01

464

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

Code of Federal Regulations, 2010 CFR

... The operator shall retain a record of all blasts for at least 3 years. Upon request, copies... (a) Name of the operator conducting the blast. (b) Location, date, and time of the blast. (c) Name, signature, and...

2010-07-01

465

14 CFR 417.229 - Far-field overpressure blast effects analysis.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Far-field overpressure blast effects analysis. 417.229 Section... § 417.229 Far-field overpressure blast effects analysis. (a) General. ...from any hazard associated with far field blast overpressure effects due to...

2010-01-01

466

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

Code of Federal Regulations, 2010 CFR

... The operator shall retain a record of all blasts for at least 3 years. Upon request, copies... (a) Name of the operator conducting the blast. (b) Location, date, and time of the blast. (c) Name, signature, and...

2010-07-01

467

30 CFR 57.6200 - Delivery to storage or blast site areas.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Delivery to storage or blast site areas. 57.6200 Section 57... § 57.6200 Delivery to storage or blast site areas. Explosive material shall...without undue delay to the storage area or blast...

2010-07-01

468

Modeling of Human Brain Tissues and Head Injuries Induced by Blast and Ballistic Impact  

E-print Network

is developed to study non-penetrating TBI. The effects of constitutive models and blast directions on finite elements simulations of blast induced TBI are investigated. Further, the effectiveness of combat helmets against non-penetrating TBI induced by blast...

Kulkarni, Sahil G

2013-11-07

469

Dosage-response relationships for community annoyance with blasting  

SciTech Connect

This paper summarizes a study of community response to blasting at two coal mines and a quarry. Over 1000 people were interviewed to determine the prevalence (that is, both intensity and extensity) of annoyance associated with long term exposure to ground vibration and airblast at distances from about 500 to 4000 meters from blasting sites. The sites were chosen, among other reasons, for their lack of unusual geologic conditions, and for the historical continuity and range of blasting activity (frequencies of blasting of two or three shots per week or less, and maximum charge weights per delay ranging from about 100 to 10,000 pounds). A major goal of this study was to attempt to infer dosage-response relationships between long term exposure to blasting and the proportion of the community highly annoyed by the blasting.

Fidell, S.; Horonjeff, R.

1982-01-01

470

Gingival abrasion and recession in manual and oscillating–rotating power brush users  

PubMed Central

Objective To assess gingival recession (GR) in manual and power toothbrush users and evaluate the relationship between GR and gingival abrasion scores (GA). Methods This was an observational (cross-sectional), single-centre, examiner-blind study involving a single-brushing exercise, with 181 young adult participants: 90 manual brush users and 91 oscillating–rotating power brush users. Participants were assessed for GR and GA as primary response variables. Secondary response variables were the level of gingival inflammation, plaque score reduction and brushing duration. Pearson correlation was used to describe the relationship between number of recession sites and number of abrasions. Prebrushing (baseline) and post-brushing GA and plaque scores were assessed and differences analysed using paired tests. Two-sample t-test was used to analyse group differences; ancova was used for analyses of post-brushing changes with baseline as covariate. Results Overall, 97.8% of the study population had at least one site of ?1 mm of gingival recession. For the manual group, this percentage was 98.9%, and for the power group, this percentage was 96.7% (P = 0.621). Post-brushing, the power group showed a significantly smaller GA increase than the manual group (P = 0.004); however, there was no significant correlation between number of recession sites and number of abrasions for either group (P ? 0.327). Conclusions Little gingival recession was observed in either toothbrush user group; the observed GR levels were comparable. Lower post-brushing gingival abrasion levels were seen in the power group. There was no correlation between gingival abrasion as a result of brushing and the observed gingival recession following use of either toothbrush. PMID:24871587

Rosema, NAM; Adam, R; Grender, JM; Van der Sluijs, E; Supranoto, SC; Van der Weijden, GA

2014-01-01

471

Glacial erosion and bedrock properties in NW Scotland: Abrasion and plucking, hardness and joint spacing  

NASA Astrophysics Data System (ADS)

Subglacial erosion beneath glaciers occurs predominantly by abrasion and plucking, producing distinct erosional forms. The controls on the relative importance of abrasion vs. plucking are poorly understood. On the one hand, glacial conditions that favour or suppress cavity formation (ice velocity, ice thickness, and water pressure) are thought to favour plucking or abrasion, respectively. Conversely, bedrock properties are also known to control landforms, but this has rarely been analysed quantitatively. In this study we compare landforms and bedrock properties of sandstone and quartzite at the bed of a palaeo-ice stream near Ullapool in NW Scotland. The boundary between the rock types is at right angles to the westward palaeo-ice flow, and palaeoglacial conditions on both rock types were similar. We report quantitative parameters for bedrock properties (Schmidt hammer hardness and joint spacing) and use morphometric parameters to analyse the landforms. Torridon sandstone is soft but thick-bedded and with a wide joint spacing. Erosional bedforms include roche moutonnées with smoothed tops and concave stoss sides, whalebacks, and elongate p-forms, indicating a high proportion of abrasion over plucking. Cambrian quartzite is hard but thin-bedded with narrow joint spacing. Erosional landforms are angular to subangular with abundant plucked lee faces, suggesting a high proportion of plucking over abrasion. Hardness and joint spacing thus exert a strong control on subglacial erosional landforms and the mechanisms that formed them. Thus glacial conditions (ice velocity, ice thickness) can only be inferred from glacial erosional landforms if the effects of bedrock properties of the substrate are considered.

Krabbendam, Maarten; Glasser, Neil F.

2011-07-01

472

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

473

Fatigue of a glass bead blasted nickel-base superalloy  

Microsoft Academic Search

Room temperature fatigue crack initiation and propagation in the wrought nickel-base superalloy Udimet 700 were investigated\\u000a with electropolished and glass bead blasted material. Cracks were found to initiate at the surface along coherent annealing\\u000a twin boundaries oriented for maximum in-plane shear stress in both the electropolished and glass bead blasted conditions even\\u000a though bead blasting more than doubled the fatigue

L. H. Burck; C. P. Sullivan; C. H. Wells

1970-01-01

474

Synergetic effect of organic cores and inorganic shells for core/shell structured composite abrasives for chemical mechanical planarization  

NASA Astrophysics Data System (ADS)

Core/shell structured organic/inorganic composite microspheres has an important potential application in efficient and damage-free chemical mechanical planarization/polishing (CMP) as a kind of novel abrasive due to its uniform non-rigid mechanical property. However, the synergistic effect of material removal between organic cores and inorganic shells of composite abrasives is ambiguous. In this work, oxide-CMP performances of various slurries, containing polystyrene (PS) spheres, solid abrasives (SiO2 or CeO2), mixed abrasives ((PS + SiO2) or (PS + CeO2)), core/shell composites (PS/SiO2 or PS/CeO2), were investigated by atomic force microscopy. Experiment results indicated that the surfaces polished by composite abrasives exhibited lower surface roughness, fewer scratches as well as lower topographical variations than those by other type of abrasives. The core/shell structure of composite abrasives plays an important role in improving CMP behavior. Moreover, the organic cores are mainly beneficial to decrease surface roughness and mechanical damages, and the inorganic shells are in favor of improving material removal rate.

Chen, Yang; Li, Zhina; Miao, Naiming

2014-09-01

475

Developments in vapour cloud explosion blast modeling.  

PubMed

TNT Equivalency methods are widely used for vapour cloud explosion blast modeling. Presently, however, other types of models are available which do not have the fundamental objections TNT Equivalency models have. TNO Multi-Energy method is increasingly accepted as a more reasonable alternative to be used as a simple and practical method. Computer codes based on computational fluid dynamics (CFD) like AutoReaGas, developed by TNO and Century Dynamics, could be used also in case a more rigorous analysis is required. Application of the Multi-Energy method requires knowledge of two parameters describing the explosion: a charge size and a charge strength. During the last years, research has led to an improved determination of the charge strength (i.e., the class number or source overpressure) to be chosen to apply the blast charts. A correlation has been derived relating the charge strength to a set of parameters describing the boundary conditions of the flammable cloud and the fuel in the cloud. A simple approach may not be satisfactory in all situations. The overpressure distribution inside a vapour cloud explosion is generally not homogeneous and the presence of obstructions causes directional blast propagation in the near field. A CFD approach, in which the actual situation is modeled, supplies case-specific results. An overview of the key aspects relevant to the application of the Multi-Energy method and CFD modeling is provided. Then the application of the two methods is demonstrated for an example problem involving the calculation of the explosion blast load on a structure at some distance from the explosion in an offshore platform complex. PMID:10677667

Mercx, W P; van den Berg, A C; Hayhurst, C J; Robertson, N J; Moran, K C

2000-01-01

476

Blast wave simulation with ground surface effect  

NASA Astrophysics Data System (ADS)

Unsteady flowfield generated by the finite strength of a shock wave is computationally simulated with the discretization method. The results indicate that the overpressure depends on the ground surface geometry as well as the distance from the point of explosion. The present approach using the new computational-fluid-dynamic technology may improve the existing theory for estimating the unsteady motion and decay of blast waves and eventually lead to better estimation of the safety distance for rocket launching.

Fujii, Kozo; Shimizu, Fumio; Tamura, Yoshiaki; Higashino, Fumio; Hinada, Motoki; Akiba, Ryojiro

477

Explosive parcel containment and blast mitigation container  

DOEpatents

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

478

Boundary-layer theory for blast waves  

NASA Technical Reports Server (NTRS)

It is profitable to consider the blast wave as a flow field consisting of two regions: the outer, which retains the properties of the inviscid solution, and the inner, which is governed by flow equations including terms expressing the effects of heat transfer and, concomitantly, viscosity. The latter region thus plays the role of a boundary layer. Reported here is an analytical method developed for the study of such layers, based on the matched asymptotic expansion technique combined with patched solutions.

Kim, K. B.; Berger, S. A.; Kamel, M. M.; Korobeinikov, V. P.; Oppenheim, A. K.

1975-01-01

479

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

480

Metal sorption on blast-furnace slag  

Microsoft Academic Search

The removal of Cu, Ni and Zn-ions from water solution by ungranulated blast-furnace slag has been studied depending on contact time, initial ion concentration, pH and solution temperature. The polymineral composition and the slag specific properties determine its high sorption activity in metal salts solutions. In the range of the concentrations studied (10?4–10?3 M), the sorption data for Cu2+, Ni2+

S. V. Dimitrova

1996-01-01

481

Mechanisms of Hearing Loss after Blast Injury to the Ear  

PubMed Central

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

482

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

483

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

484

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

485

Brain injury from explosive blast: description and clinical management.  

PubMed

Accumulating clinical experience is indicating that explosive blast brain injury is becoming recognized as a disease distinct from the penetrating form of blast injury as well as the classic closed head injury (CHI). In recent US conflicts in Iraq and Afghanistan, over 60% of combat casualties were from explosive blast with the hallmark explosive weapon being the improvised explosive device (IED). Explosive blast TBI is a condition afflicting many combat injured warfighters potentially constituting another category of TBI. Clinically, it shares many features with conventional TBI but possesses some unique aspects. In its mild form, it also shares many clinical features with PTSD but here again has distinct aspects. Although military medical providers depend on civilian standard of care guidelines when managing explosive blast mTBI, they are continually adapting their medical practice in order to optimize the treatment of this disease, particularly in a theater of war. It is clear that further rigorous scientific study of exp