Sample records for v-notch impact testing

  1. Computer simulation of the Charpy V-notch toughness test

    Microsoft Academic Search

    D. M. Jr

    1977-01-01

    The dynamic Charpy V-notch test was simulated on a computer. The calculational models (for A-533 Grade B class 1 steel) used both a rounded and a flat-tipped striker. The notch stress\\/strain state was found to be independent of the three-point loading type and was most strongly correlated with notch-opening displacement. The dynamic stress\\/strain state at the time of fracture initiation

  2. Size Effects in the Charpy V-Notch Test

    Microsoft Academic Search

    A. A. Benzerga; V. Tvergaard; A. Needleman

    2002-01-01

    Issues related to the size dependence of the upper shelf energy (USE) and the ductile-to-brittle transition temperature (DBTT) in the Charpy V-notch test are investigated. Emphasis is placed on the interplay between inertial, strain rate hardening, strain hardening, thermal softening and material length scale effects. Geometrically similar specimens are considered first. For such specimens, the ductile-to-brittle transition temperature is found

  3. Preparation of reconstituted Charpy V-notch impact specimens for generating pressure vessel steel fracture toughness data

    Microsoft Academic Search

    J. S. Perrin; E. O. Fromm; W. L. Server; P. E. McConnell

    1982-01-01

    The arc stud welding process has been adapted for use in producing reconstituted Charpy V-notch impact specimens. In this process, each half of a tested and fractured Charpy specimen is used as the central region of a reconstituted specimen. End tabs are joined to one half of a fractured specimen by a specially designed stud welding apparatus. SA533B-1 and SA508-2

  4. Material inertia and size effects in the Charpy V-notch test

    Microsoft Academic Search

    D. A. DeSandre; A. A. Benzerga; V. Tvergaard; A. Needleman

    2004-01-01

    The effect of material inertia on the size dependence of the absorbed energy in the Charpy V-notch test is investigated. The material response is characterized by an elastic-viscoplastic constitutive relation for a porous plastic solid, with adiabatic heating due to plastic dissipation and the resulting thermal softening accounted for. The onset of cleavage is taken to occur when a critical

  5. Preparation of reconstituted Charpy V-notch impact specimens for generating pressure vessel steel fracture toughness data

    SciTech Connect

    Perrin, J.S. (Fracture Control Corp., Goleta, CA); Fromm, E.O.; Server, W.L.; McConnell, P.E.

    1982-01-01

    The arc stud welding process has been adapted for use in producing reconstituted Charpy V-notch impact specimens. In this process, each half of a tested and fractured Charpy specimen is used as the central region of a reconstituted specimen. End tabs are joined to one half of a fractured specimen by a specially designed stud welding apparatus. SA533B-1 and SA508-2 unirradiated and irradiated pressure vessel steel specimens have been produced. Both conventional and precracked reconstituted specimen data have been produced. Both types of data have been shown to be in excellent agreement with original specimen data. The arc stud welding process can therefore be used to increase the amount of data obtainable from a limited number of specimens or to obtain Charpy data when full size specimens cannot otherwise be obtained.

  6. New and Renewal NIST SRMs/RMs NIST SRMs 2216, 2218, and 2219 Miniaturized Charpy V-Notch

    E-print Network

    -Notch (MCVN) KLST Impact Specimen SRMs to verify the performance of small-scale impact testing machines usedNew and Renewal NIST SRMs/RMs NIST SRMs 2216, 2218, and 2219 Miniaturized Charpy V-Notch Impact Specimens SRM 2216 Miniaturized Low-Energy Charpy V-Notch KLST Impact Specimen SRM 2218 Miniaturized High

  7. Use of forces from instrumented Charpy V-notch testing to determine crack-arrest toughness

    SciTech Connect

    Iskander, S.K.; Nanstad, R.K.; Sokolov, M.A.; McCabe, D.E.; Hutton, J.T.

    1996-06-01

    The objective of this investigation is an estimation of the crack-arrest toughness, particularly of irradiated materials, from voltage versus time output of an instrumented setup during a test on a Charpy V-notch (CVN) specimen. This voltage versus time trace (which can be converted to force versus displacement) displays events during fracture of the specimen. Various stages of the fracture process can be identified on the trace, including an arrest point indicating arrest of brittle fracture. The force at arrest, F{sub a}, versus test temperature, T, relationship is examined to explore possible relationships to other experimental measures of crack-arrest toughness such as the drop-weight nil-ductility temperature (NDT), or crack-arrest toughness, K{sub a}. For a wide range of weld and plate materials, the temperature at which F{sub a} = 2.45 kN correlates with NDT with a standard deviation, sigma, of about 11 K. Excluding the so-called low upper-shelf energy (USE) welds from the analysis resulted in F{sub a} = 4.12 kN and {sigma} = 6.6 K. The estimates of the correlation of the temperature for F{sub a} = 7.4 kN with the temperature at 100-MPa{radical}m level for a mean American Society of Mechanical Engineers (ASME) type K{sub Ia} curve through crack-arrest toughness values show that prediction of conservative values of K{sub a} are possible.

  8. Effects of Notch Misalignment and Tip Radius on Displacement Field in V-Notch Rail Shear Test as Determined by Photogrammetry

    NASA Technical Reports Server (NTRS)

    Hill, Charles S.; Oliveras, Ovidio M.

    2011-01-01

    Evolution of the 3D strain field during ASTM-D-7078 v-notch rail shear tests on 8-ply quasi-isotropic carbon fiber/epoxy laminates was determined by optical photogrammetry using an ARAMIS system. Specimens having non-optimal geometry and minor discrepancies in dimensional tolerances were shown to display non-symmetry and/or stress concentration in the vicinity of the notch relative to a specimen meeting the requirements of the standard, but resulting shear strength and modulus values remained within acceptable bounds of standard deviation. Based on these results, and reported difficulty machining specimens to the required tolerances using available methods, it is suggested that a parametric study combining analytical methods and experiment may provide rationale to increase the tolerances on some specimen dimensions, reducing machining costs, increasing the proportion of acceptable results, and enabling a wider adoption of the test method.

  9. Effect of notch dimension on the fatigue life of V-notched structure

    Microsoft Academic Search

    Cheng Chang-zheng; Recho Naman; Niu Zhong-rong; Zhou Huan-lin

    2011-01-01

    The stress singularity degree associated to a V-notch has a great influence on the fatigue life of V-notched structure. The growth rate of the crack initiated at the tip of a V-notch depends on the stress singularity of the V-notch. The fatigue life accompanying with this small crack will represent a large amount of the total fatigue life. In this

  10. Experimental study on the material dynamic fracture properties by Instrumented Charpy Impact test with single specimen method

    Microsoft Academic Search

    F. Jian; D. Fulian; W. Chengzhong

    2003-01-01

    With the determination of load-time curve recorded by Amsler\\/Roell RKP 450 Instrumented Charpy Impact test and based on the Newton's Second Law, Impact character of a single standard V-notch specimen of X70 pipeline steel under the low temperature -70 ^{circ}C was investigated by studying the impact energy distribution. It was revealed that maximum load point (Fm point) was not exact

  11. Low temperature impact toughness of the main gas pipeline steel after long-term degradation

    NASA Astrophysics Data System (ADS)

    Maruschak, Pavlo; Danyliuk, Iryna; Bishchak, Roman; Vuherer, Tomaž

    2014-12-01

    The correlation of microstructure, temperature and Charpy V-notch impact properties of a steel 17G1S pipeline steel was investigated in this study. Within the concept of physical mesomechanics, the dynamic failure of specimens is represented as a successive process of the loss of shear stability, which takes place at different structural/scale levels of the material. Characteristic stages are analyzed for various modes of failure, moreover, typical levels of loading and oscillation periods, etc. are determined. Relations between low temperature derived through this test, microstructures and Charpy (V-notch) toughness test results are also discussed in this paper.

  12. Performance verification of impact machines for testing plastics

    SciTech Connect

    Siewert, T.A.; Vigliotti, D.P.; Dirling, L.B.; McCowan, C.N.

    1999-12-01

    Valid comparison of impact test energies reported by various organizations and over time depends on consistent performance of impact test machines. This paper investigates the influence of various specimen and test parameters on impact energies in the 1 J to 2 J range for both Charpy V-notch and Izod procedures, leading toward the identification of a suitable material for use in a program to verify machine performance. The authors investigated the influences on the absorbed energy of machine design, test material, specimen cross sectional area, and machine energy range. For comparison to published round robin data on common plastics, this study used some common metallic alloys, including those used in the international verification program for metals impact machines and in informal calibration programs of tensile machines. The alloys that were evaluated include AISI type 4340 steel, and five aluminum alloys: 2014-T6, 2024-T351, 2219-T87, 6061-T6, and 7075-T6. They found that certain metallic alloys have coefficients of variation comparable to those of the best plastics that are reported in the literature. Also, they found that the differences in absorbed energy between two designs of machines are smaller than the differences that can be attributed to the specimens alone.

  13. CALIBRATION OF A 90 DEGREE V-NOTCH WEIR USING PARAMETERS OTHER THAN UPSTREAM HEAD

    EPA Science Inventory

    Traditional calibration of 90 degrees V-Notch Weirs has involved the establishment of a head-discharge relationship where the head is measured upstream of weir drawdown effects. This parameter is often difficult to mesure in field weir installations. Two other parameters are prop...

  14. Impact strength of nylon 6 and 66 in the dry and moist states

    Microsoft Academic Search

    K. Wiebusch; R. Richter

    1986-01-01

    The impact strength of nylon was determined by the modified Charpy test with double-V notches described in DIN 53753, because\\u000a it cannot be reliably assessed by the notched Charpy and Izod tests. This test was adjusted to obtain a sensitive, accurate\\u000a and reproducible method for the determination of impact strength in the dry and moist states. In the light of

  15. Effects of microstructure on inverse fracture occurring during drop-weight tear testing of high-toughness X70 pipeline steels

    Microsoft Academic Search

    Byoungchul Hwang; Yang Gon Kim; Sunghak Lee; Nack J. Kim; Jang Yong Yoo

    2005-01-01

    The effects of microstructure on inverse fracture occurring in the hammer-impacted region were analyzed after conducting a drop-weight tear test (DWTT) on high-toughness pipeline steels. Three kinds of steels were fabricated by varying the alloying elements, and their microstructures were varied by the rolling conditions. The pressed-notch (PN) or chevron-notch (CN) DWTT and Charpy V-notch (CVN) impact tests were conducted

  16. Effects of Notch Shape and Specimen Thickness on Drop-Weight Tear Test Properties of API X70 and X80 Line-Pipe Steels

    Microsoft Academic Search

    Sang Yong Shin; Byoungchul Hwang; Sunghak Lee; Ki Bong Kang

    2007-01-01

    In the present study, effects of notch shape and specimen thickness on drop-weight tear test (DWTT) properties of API X70\\u000a and X80 line-pipe steels fabricated by varying hot-rolling conditions were investigated. The DWTT was conducted on the rolled\\u000a steels, and the results were discussed in comparison with the Charpy V-notch (CVN) impact test and crack-tip opening angle\\u000a (CTOA) test data.

  17. Measurement of fracture initiation toughness and crack resistance in instrumented Charpy impact testing

    Microsoft Academic Search

    J. P Tronskar; M. A Mannan; M. O Lai

    2002-01-01

    A new method has been developed involving direct measurement of the load-line displacement during instrumented Charpy testing. The method uses a laser interferometer to measure displacement in addition to the load-line displacement derived from the load signal. Tests were conducted using fatigue precracked and V-notched test pieces in the temperature range +23°C to ?80°C on a conventional ship grade steel,

  18. Effect of welding on impact toughness of butt-joints in a titanium alloy

    Microsoft Academic Search

    Wei Zhou; K. G. Chew

    2003-01-01

    Impact toughness of a gas tungsten arc welded Ti–6Al–4V alloy butt-joint was evaluated at room temperature using standard Charpy V-notch specimens. The Charpy specimens were prepared with notch roots located either in the parent metal, in the heat-affected zone (HAZ), or in the weld metal. Optical metallography and Vickers microhardness test showed that the weld metal has the coarsest grains

  19. Correlation of crack-tip opening angle for stable crack propagation with charpy and drop-weight tear test properties in high-toughness API X70 pipeline steels

    Microsoft Academic Search

    Byoungchul Hwang; Sang Yong Shin; Sunghak Lee; Nack J. Kim; Sangho Kim; Ki Bong Kang

    2006-01-01

    Correlation between Charpy V-notch (CVN) impact properties, drop-weight tear test (DWTT) properties, and crack-tip opening\\u000a angles for stable crack propagation (CTOAsc) in high-toughness API X70 pipeline steels was investigated in this study. Two-specimen CTOA test (TSCT) was conducted on\\u000a the rolled steel materials to measure the CTOAsc, and the test results were compared to the CVN and DWTT data to

  20. Small punch test evaluation of intergranular embrittlement of an alloy steel

    Microsoft Academic Search

    J. M. Baik; O. Buck; J. Kameda

    1983-01-01

    The ductile-brittle transition temperature in steel is commonly determined using Charpy V-notch impact specimens as specified by ASTM E23-81. In some specific cases, however, the use of this standardized test specimen may be impractical, if not impossible. For instance, it is well known that ferritic steels show a substantial degradation of the mechanical properties after long time exposure to an

  1. Southern Impact Testing Alliance (SITA)

    NASA Technical Reports Server (NTRS)

    Hubbs, Whitney; Roebuck, Brian; Zwiener, Mark; Wells, Brian

    2009-01-01

    Efforts to form this Alliance began in 2008 to showcase the impact testing capabilities within the southern United States. Impact testing customers can utilize SITA partner capabilities to provide supporting data during all program phases-materials/component/ flight hardware design, development, and qualification. This approach would allow programs to reduce risk by providing low cost testing during early development to flush out possible problems before moving on to larger scale1 higher cost testing. Various SITA partners would participate in impact testing depending on program phase-materials characterization, component/subsystem characterization, full-scale system testing for qualification. SITA partners would collaborate with the customer to develop an integrated test approach during early program phases. Modeling and analysis validation can start with small-scale testing to ensure a level of confidence for the next step large or full-scale conclusive test shots. Impact Testing Facility (ITF) was established and began its research in spacecraft debris shielding in the early 1960's and played a malor role in the International Space Station debris shield development. As a result of return to flight testing after the loss of STS-107 (Columbia) MSFC ITF realized the need to expand their capabilities beyond meteoroid and space debris impact testing. MSFC partnered with the Department of Defense and academic institutions as collaborative efforts to gain and share knowledge that would benefit the Space Agency as well as the DoD. MSFC ITF current capabilities include: Hypervelocity impact testing, ballistic impact testing, and environmental impact testing.

  2. TAYLOR IMPACT TESTS: DETAILED REPORT

    Microsoft Academic Search

    Biswajit Banerjee

    Taylor impacts tests were originally devised to determine the dynamic yield strength of materials at moderate strain rates. More recently, such tests have been used extensively to validate numerical codes for the simulation of plastic deformation. In this work, we use the material point method to simulate a number of Taylor impact tests. The goal is to par- tially validate

  3. Bond Inspection by Impact Test

    NASA Astrophysics Data System (ADS)

    Yang, Y.; Xiang, D.; Qin, Y.; Li, F.; Coulter, R. V.

    2010-02-01

    Kissing bond detection has been a challenging issue for NDE of bonded structures in aeronautical industry. A novel impact test technique for bond inspection has been developed, which shows great potential for kissing bond detection. The impact test employs a solenoid to produce impact forces in a bonded structure, and the induced elastic wave in the structure was picked up by an EMAT sensor, which located side by side with the solenoid. Both solenoid and EMAT sensor are integrated into a tap header that is mounted onto an automatic 2-D scanner to realize an automatic 2-D scanning. Multiple samples with artificial defects including kissing bonds and disbonds were used to test the impact test technique. The results show that those bond defects in the samples can be detected by the developed impact test technique. For comparison purpose, those samples were also tested with traditional ultrasonic C-scan.

  4. Impacting device for testing insulation

    NASA Technical Reports Server (NTRS)

    Redmon, J. W. (inventor)

    1984-01-01

    An electro-mechanical impacting device for testing the bonding of foam insulation to metal is descirbed. The device lightly impacts foam insulation attached to metal to determine whether the insulation is properly bonded to the metal and to determine the quality of the bond. A force measuring device, preferably a load cell mounted on the impacting device, measures the force of the impact and the duration of the time the hammer head is actually in contact with the insulation. The impactor is designed in the form of a handgun having a driving spring which can propel a plunger forward to cause a hammer head to impact the insulation. The device utilizes a trigger mechanism which provides precise adjustements, allowing fireproof operation.

  5. Effects of microstructure on inverse fracture occurring during drop-weight tear testing of high-toughness X70 pipeline steels

    Microsoft Academic Search

    Byoungchul Hwang; Yang Gon Kim; Sunghak Lee; Nack J. Kim; Jang Yong Yoo

    2005-01-01

    The effects of microstructure on inverse fracture occurring in the hammer-impacted region were analyzed after conducting a\\u000a drop-weight tear test (DWTT) on high-toughness pipeline steels. Three kinds of steels were fabricated by varying the alloying\\u000a elements, and their microstructures were varied by the rolling conditions. The pressed-notch (PN) or chevron-notch (CN) DWTT\\u000a and Charpy V-notch (CVN) impact tests were conducted

  6. 30 CFR 7.46 - Impact test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Impact test. 7.46 Section...APPLICANT OR THIRD PARTY Battery Assemblies § 7.46 Impact test. (a) Test procedures...support blocks, with the battery cells completely...individual cells. At the test temperature range...

  7. 30 CFR 7.46 - Impact test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Impact test. 7.46 Section...APPLICANT OR THIRD PARTY Battery Assemblies § 7.46 Impact test. (a) Test procedures...support blocks, with the battery cells completely...individual cells. At the test temperature range...

  8. 30 CFR 7.46 - Impact test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Impact test. 7.46 Section...APPLICANT OR THIRD PARTY Battery Assemblies § 7.46 Impact test. (a) Test procedures...support blocks, with the battery cells completely...individual cells. At the test temperature range...

  9. Drop impact test - mechanics & physics of failure

    Microsoft Academic Search

    E. H. Wong; K. M. Lim; N. Lee; S. Seah; C. Hoe; J. Wang

    2002-01-01

    This paper deals with the mechanics and physics of board-level drop test with the intention of providing the fundamental understanding required to design and analyse the results of a drop test. Three finite element analyses were performed to understand the physics of failure in board-level drop impact: (i) velocity impact of a PCB - modeled as a beam; (ii) velocity

  10. Solid rocket booster water impact test

    Microsoft Academic Search

    F. Bugg

    1982-01-01

    Water impact drop tests were performed on the space shuttle solid rocket boosters (SRB). Peak water impact pressures and pressure\\/time traces were measured for various impact velocities using a two-dimensional, full-scale SRB aft skirt internal ring model. Passive burst disc-type pressure transducers were calibrated for use on flight SRB's. The effects on impact pressure of small ring configuration changes and

  11. Impact Testing of Stainless Steel Materials

    SciTech Connect

    R. K. Blandford; D. K. Morton; T. E. Rahl; S. D. Snow

    2005-07-01

    Stainless steels are used for the construction of numerous spent nuclear fuel or radioactive material containers that may be subjected to high strains and moderate strain rates (10 to 200 per second) during accidental drop events. Mechanical characteristics of these materials under dynamic (impact) loads in the strain rate range of concern are not well documented. The goal of the work presented in this paper was to improve understanding of moderate strain rate phenomena on these materials. Utilizing a drop-weight impact test machine and relatively large test specimens (1/2-inch thick), initial test efforts focused on the tensile behavior of specific stainless steel materials during impact loading. Impact tests of 304L and 316L stainless steel test specimens at two different strain rates, 25 per second (304L and 316L material) and 50 per second (304L material) were performed for comparison to their quasi-static tensile test properties. Elevated strain rate stress-strain curves for the two materials were determined using the impact test machine and a “total impact energy” approach. This approach considered the deformation energy required to strain the specimens at a given strain rate. The material data developed was then utilized in analytical simulations to validate the final elevated stress-strain curves. The procedures used during testing and the results obtained are described in this paper.

  12. Phase transformation and impact properties in the experimentally simulated weld heat-affected zone of a reduced activation ferritic/martensitic steel

    NASA Astrophysics Data System (ADS)

    Moon, Joonoh; Lee, Chang-Hoon; Lee, Tae-Ho; Jang, Min-Ho; Park, Min-Gu; Han, Heung Nam

    2014-12-01

    In this work, the phase transformation and impact properties in the weld heat-affected zone (HAZ) of a reduced activation ferritic/martensitic (RAFM) steel are investigated. The HAZs were experimentally simulated using a Gleeble simulator. The base steel consisted of tempered martensite through normalizing at 1000 °C and tempering at 750 °C, while the HAZs consisted of martensite, ?-ferrite and a small volume of autotempered martensite. The impact properties using a Charpy V-notch impact test revealed that the HAZs showed poor impact properties due to the formation of martensite and ?-ferrite as compared with the base steel. In addition, the impact properties of the HAZs further deteriorated with an increase in the ?-ferrite fraction caused by increasing the peak temperature. The impact properties of the HAZs could be improved through the formation of tempered martensite after post weld heat treatment (PWHT), but they remained lower than that of the base steel because the ?-ferrite remained in the tempered HAZs.

  13. Charpy Impact Verification We evaluate the performance of pendulum impact test

    E-print Network

    Perkins, Richard A.

    Charpy Impact Verification METALS We evaluate the performance of pendulum impact test machines used pendulum impact test machines are currently used worldwide to certify construction steel, as described

  14. Dynamic fracture toughness and Charpy impact properties of an AISI 403 martensitic stainless steel

    NASA Astrophysics Data System (ADS)

    Sreenivasan, P. R.; Ray, S. K.; Mannan, S. L.; Rodriguez, P.

    1996-04-01

    Dynamic fracture toughness and Charpy impact properties of a normalised and tempered AISI 403 martensitic stainless steel obtained from instrumented impact tests are presented. Procedures for estimating dynamic fracture toughness ( KId) from the load-time traces obtained in instrumented tests of unprecracked Charpy V-notch (CVN) specimens are considered. The estimated KId values show reasonable agreement with those obtained from instrumented drop-weight and precracked Charpy tests. Also, except in the upper transition and uppershelf regions, the ASME KIR curve is generally conservative (i.e. gives lower KId values) when compared to the above KId estimates. The conservatism of the ASME KIR at the upper transition and uppershelf temperatures needs verification/validation. The lowest KId values estimated at the lower shelf temperatures for the above steel, namely, 33-42 MPa?m are in good agreement with the reported values of 35-50 MPa?m for the same steel in the literature.

  15. Impact testing of textile composite materials

    NASA Technical Reports Server (NTRS)

    Portanova, Marc

    1995-01-01

    The objectives of this report were to evaluate the impact damage resistance and damage tolerance of a variety of textile composite materials. Static indentation and impact tests were performed on the stitched and unstitched uniweave composites constructed from AS4/3501-6 Carbon/Epoxy with a fiberglass yarn woven in to hold the fibers together while being stitched. Compression and tension were measured after the tests to determine the damage resistance, residual strength and the damage tolerance of the specimens.

  16. Instrumented tensile-impact tests of bone

    Microsoft Academic Search

    S. Saha; W. C. Hayes

    1974-01-01

    An instrumented pendulum-type impact tester was used to obtain tensile-impact properties for compact bone. Load-time histories\\u000a throughout impact were recorded. Impact tests on 50 longitudinally oriented fresh-beef-bone samples yielded a proportional\\u000a limit of 9.64.1 ksi (66.228.2 MPa), an ultimate stress of 17.65.3 ksi (121.336.5 MPa) and an energy-absorption capacity\\u000a of 14285 in. Ib\\/in.2 (2490014900 J\\/m2). A static tensile strength of

  17. Impact testing on composite fan blades

    NASA Technical Reports Server (NTRS)

    Johns, R. H.

    1974-01-01

    The results of impact tests on large, fiber composite fan blades for aircraft turbofan engine applications are discussed. Solid composite blades of two different sizes and designs were tested. Both graphite/epoxy and boron/epoxy were evaluated. In addition, a spar-shell blade design was tested that had a boron/epoxy shell bonded to a titanium spar. All blades were tested one at a time in a rotating arm rig to simulate engine operating conditions. Impacting media included small gravel, two inch diameter ice balls, gelatin and RTV foam-simulated birds, as well as starlings and pigeons. The results showed little difference in performance between the graphite and boron/epoxy blades. The results also indicate that composite blades may be able to tolerate ice ball and small bird impacts but need improvement to tolerate birds in the small duck and larger category.

  18. FOD impact testing of composite fan blades

    NASA Technical Reports Server (NTRS)

    Johns, R. H.

    1974-01-01

    The results of impact tests on large, fiber composite fan blades for aircraft turbofan engine applications are discussed. Solid composite blades of two different sizes and designs were tested. Both graphite/epoxy and boron/epoxy were evaluated. In addition, a spar-shell blade design was tested that had a boron/epoxy shell bonded to a titanium spar. All blades were tested one at a time in a rotating arm rig to simulate engine operating conditions. Impacting media included small gravel, two inch diameter ice balls, gelatin, and RTV foam-simulated birds, as well as starlings and pigeons. The results showed little difference in performance between the graphite and boron/epoxy blades. The results also indicate that composite blades may be able to tolerate ice ball and small bird impacts but need improvement to tolerate birds in the small duck and larger category.

  19. FOD impact testing of composite fan blades

    NASA Technical Reports Server (NTRS)

    Johns, R. H.

    1974-01-01

    The results of impact tests on large, fiber composite fan blades for aircraft turbofan engine applications are discussed. Solid composite blades of two different sizes and designs were tested. Both graphite/epoxy and boron/epoxy were evaluated. In addition, a spar-shell blade design was tested that had a boron/epoxy shell bonded to a titanium spar. All blades were tested one at a time in a rotating arm rig to simulate engine operating conditions. Impacting media included small gravel, two inch diameter ice balls, gelatin and RTV foam-simulated birds, as well as starlings and pigeons. The results showed little difference in performance between the graphite and boron/epoxy blades. The results also indicate that composite blades may be able to tolerate ice ball and small bird impacts but need improvement to tolerate birds in the small duck and larger category.

  20. Mechanical Impact Testing: A Statistical Measurement

    NASA Technical Reports Server (NTRS)

    Engel, Carl D.; Herald, Stephen D.; Davis, S. Eddie

    2005-01-01

    In the decades since the 1950s, when NASA first developed mechanical impact testing of materials, researchers have continued efforts to gain a better understanding of the chemical, mechanical, and thermodynamic nature of the phenomenon. The impact mechanism is a real combustion ignition mechanism that needs understanding in the design of an oxygen system. The use of test data from this test method has been questioned due to lack of a clear method of application of the data and variability found between tests, material batches, and facilities. This effort explores a large database that has accumulated over a number of years and explores its overall nature. Moreover, testing was performed to determine the statistical nature of the test procedure to help establish sample size guidelines for material characterization. The current method of determining a pass/fail criterion based on either light emission or sound report or material charring is questioned.

  1. Bar Impact Tests on Alumina (AD995)

    NASA Astrophysics Data System (ADS)

    Cazamias, James U.; Reinhart, William D.; Konrad, Carl H.; Chhabildas, Lalit C.; Bless, Stephan J.

    2002-07-01

    Dynamic strength may be inferred from bar impact tests, although interpretation of the data is affected by the time-to-failure of the target bar. To clarify the mechanics, tests with graded density impactors were conducted on bare and confined bars, 12 and 19 mm in diameter, cut from blocks of AD995 alumina. Manganin gauge and VISAR diagnostics were employed. Larger rods displayed higher strength. In some tests the "true" yield stress of ˜4.5 GPa was achieved.

  2. A study of the fracture process and factors that control toughness variability in Charpy V-notch specimens

    Microsoft Academic Search

    Real Bouchard

    2004-01-01

    La presente etude a ete initiee pour developper une comprehension quantitative du processus de rupture avec les facteurs qui controlent la dispersion des mesures de tenacite lorsque des eprouvettes Charpy entaillees en V sont utilisees. Un grand nombre d'essais ont ete realises pour un acier C-Mn: eprouvettes Charpy testees sous impact, eprouvettes Charpy testees en flexion lente, eprouvettes axisymetriques entaillees

  3. Effects of Notch Location on Heat-affected Zone Impact Properties of SA-516 Steels

    NASA Astrophysics Data System (ADS)

    Hong, Jaekeun; Park, Jihong; Kang, Chungyun

    In case of welding for pressure retaining parts on nuclear components, the verifications of heat affected zone (HAZ) impact properties are required according to application codes such as ASME Sec. III, RCC-M, KEPIC (Korea Electric Power Industry Code) MN, and JEA (Japan Electric Association) Code. Especially in case of Charpy V-notch tests of HAZ, the requirements of notch location and specimen direction have greatly impact on the reliability and consistency of the test results. For the establishment of newly adequate impact test requirements, the requirements about the HAZ impact tests of ASME Section III, RCC-M, KEPIC MN and JEA code were researched in this study. And also the HAZ impact test requirements about surveillance tests in nuclear reactor vessels were compared and investigated. For the effects of the notch location and specimen direction on the impact properties, SA-516 Gr.70 materials were investigated. The specimens were fabricated with using shielded metal-arc welding, and maximum heat inputs were controlled within the range of 16˜27 kJ/cm. Especially, this research showed the lateral expansion values and absorbed energies were not compatible and the impact test results were varied depending on notch location and specimen direction. Based on this study, newly adequate impact test requirements of HAZ were proposed.

  4. 16 CFR 1203.11 - Marking the impact test line.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.11 Marking the impact test line. Prior to testing, the impact test line shall be...

  5. Apollo command module land impact tests

    NASA Technical Reports Server (NTRS)

    Mccullough, J. E.; Lands, J. F., Jr.

    1972-01-01

    Full-scale-model and actual spacecraft were impact tested to define the emergency land-landing capability of the Apollo command module. Structural accelerations and strains were recorded on analog instrumentation, and a summary to these data is included. The landing kinematics were obtained from high-speed photography. Photographs of the structural damage caused during the tests are included. Even though extensive damage can be expected, the crew will receive nothing more than minor injuries during the majority of the probable landing conditions.

  6. 16 CFR 1203.11 - Marking the impact test line.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Marking the impact test line. 1203.11 Section 1203.11... The Standard § 1203.11 Marking the impact test line. Prior to testing, the impact test line shall be determined for each...

  7. 16 CFR 1203.11 - Marking the impact test line.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Marking the impact test line. 1203.11 Section 1203.11... The Standard § 1203.11 Marking the impact test line. Prior to testing, the impact test line shall be determined for each...

  8. 16 CFR 1203.11 - Marking the impact test line.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Marking the impact test line. 1203.11 Section 1203.11... The Standard § 1203.11 Marking the impact test line. Prior to testing, the impact test line shall be determined for each...

  9. J 0.2-values by impact testing

    Microsoft Academic Search

    F Ramsteiner

    1999-01-01

    A drop weight testing machine is described to measure the J0.2-values of polymers in impact within the frame work of fracture mechanics. By changing the weight of a piston falling from the same drop height on the specimen, the impact velocity is constant but the impact energy is varied. This principle of impact testing is applied to the three point

  10. On Low-Velocity Impact Testing of Composite Materials

    Microsoft Academic Search

    Peter O. Sjoblom; J. Timothy Hartness; Tobey M. Cordell

    1988-01-01

    The importance of understanding the response of structural composites to impact cannot be overstated. This understanding includes both the impact phenomena themselves and the influence of materials properties on the impact response. This paper presents the need for instrumented testing to optimize our understanding of the impact event, especially the response of the impacted material. The conclusion is drawn that

  11. Low-Velocity Impact Testing Horacio Dante Espinosa, Northwestern University

    E-print Network

    Espinosa, Horacio D.

    Low-Velocity Impact Testing Horacio Dante Espinosa, Northwestern University Sia Nemat-Nasser, University of California, San Diego IMPACT TESTS are used to study dynamic deformation and failure modes, or rod-on-rod experiments. Two types of plate-on-plate impact tests have been devel- oped: wave

  12. The GISS sounding temperature impact test

    NASA Technical Reports Server (NTRS)

    Halem, M.; Ghil, M.; Atlas, R.; Susskind, J.; Quirk, W. J.

    1978-01-01

    The impact of DST 5 and DST 6 satellite sounding data on mid-range forecasting was studied. The GISS temperature sounding technique, the GISS time-continuous four-dimensional assimilation procedure based on optimal statistical analysis, the GISS forecast model, and the verification techniques developed, including impact on local precipitation forecasts are described. It is found that the impact of sounding data was substantial and beneficial for the winter test period, Jan. 29 - Feb. 21. 1976. Forecasts started from initial state obtained with the aid of satellite data showed a mean improvement of about 4 points in the 48 and 772 hours Sub 1 scores as verified over North America and Europe. This corresponds to an 8 to 12 hour forecast improvement in the forecast range at 48 hours. An automated local precipitation forecast model applied to 128 cities in the United States showed on an average 15% improvement when satellite data was used for numerical forecasts. The improvement was 75% in the midwest.

  13. Elemental Water Impact Test: Phase 1 20-Inch Hemisphere

    NASA Technical Reports Server (NTRS)

    Vassilakos, Gregory J.

    2015-01-01

    Spacecraft are being designed based on LS-DYNA simulations of water landing impacts. The Elemental Water Impact Test (EWIT) series was undertaken to assess the accuracy of LS-DYNA water impact simulations. Phase 1 of the EWIT series featured water impact tests of a 20-inch hemisphere dropped from heights of 5 feet and 10 feet. The hemisphere was outfitted with an accelerometer and three pressure gages. The focus of this report is the correlation of analytical models against test data.

  14. Impact testing of structural biological materials

    Microsoft Academic Search

    Steve Lee; Ekaterina E. Novitskaya; Brandon Reynante; Joshua Vasquez; Robert Urbaniak; Tsukasa Takahashi; Evan Woolley; Luca Tombolato; Po-Yu Chen; Joanna McKittrick

    2011-01-01

    Structural biological materials must be highly impact resistant, as appendages such as antlers and horns must sustain repeated, seasonal impact loads. Determining the impact damage progression along with the impact strength is very important for understanding how nature has optimized the structure and properties of biological materials in order to guide the design of superior bio-inspired synthetic materials. A drop

  15. The Impact of Concurrent Coverage Metrics on Testing Effectiveness

    E-print Network

    The Impact of Concurrent Coverage Metrics on Testing Effectiveness Shin Hong, Matt Staats, Jaemin. While a large body of evidence exists exploring the impact of structural coverage metrics on testing of Computer Science University of Nebraska-Lincoln Lincoln, NE grother@cse.unl.edu Abstract--When testing

  16. Instrumented impact testing at high velocities

    Microsoft Academic Search

    Daniel Delfosse; Gilles Pageau; Roger Bennett; Anoush Poursartip

    1993-01-01

    Impact loading of carbon fiber-reinforced plastic CFRP) aircraft parts is a major concern. Birds or hailstones striking an aircraft generally have a low mass and a high velocity, whereas typically instrumented impact experiments are performed with a high mass and a low velocity. Our aim has been to build an instrumented impact facility with a low-mass projectile capable of simulating

  17. Impact testing of concrete using a drop-weight impact machine

    Microsoft Academic Search

    N. Banthia; S. Mindess; A. Bentur; M. Pigeon

    1989-01-01

    A detailed description of the instrumented dropweight impact machine is presented. The instrumentation, the calibration, the inertial loading correction, and the dynamic analysis of a concrete beam specimen undergoing three-point impact flexural loading are described. Some results, using such an impact testing machine, obtained from tests done on plain concrete, fiber-reinforced concrete, and conventionally reinforced concrete are presented. It is

  18. PERSPECTIVES AND PARADIGMS Advancing impact prediction and hypothesis testing

    E-print Network

    Ricciardi, Anthony

    PERSPECTIVES AND PARADIGMS Advancing impact prediction and hypothesis testing in invasion ecology impacts of existing, emerging and potential invasive species. We argue that many ecologically damaging and trophically analogous native species may allow prediction of invader ecological impact. We review the utility

  19. PERSPECTIVES AND PARADIGMS Advancing impact prediction and hypothesis testing

    E-print Network

    Ricciardi, Anthony

    PERSPECTIVES AND PARADIGMS Advancing impact prediction and hypothesis testing in invasion ecology methodologies that can forecast the ecological impacts of existing, emerging and potential invasive species. We of invader ecological impact. We review the utility of species trait comparisons and the history and context

  20. Psychometric Impacts of Above-Level Testing 

    E-print Network

    Warne, Russell Thomas

    2012-07-16

    -level testing has not been subject to careful psychometric scrutiny. In this study, I examine reliability data, growth trajectories, distributions, and group differences of above-level test scores obtained from the Iowa Tests of Basic Skills (ITBS) and Iowa...

  1. Particle impact tests. [simulation of micrometeoroid damage to orbiter surface

    NASA Technical Reports Server (NTRS)

    Komatsu, G. K.

    1978-01-01

    Particle impact tests were performed on three types of orbiter surface with a micrometeoroid facility. The test equipment electrostatically accelerated micron sized particles to high velocities simulating micrometeoroid impacts. Test particles were titanium diboride with typical velocities in the range 1 to 2.3 km x sec/1 and equivalent particle diameters in the range 4 to 16 microns. Impact angles to the material surface were 90, 60 and 30 degrees. The particle impact sites were located on the sample surfaces and craters were photographed with a magnification of 400X.

  2. Rail-car impact tests with steel coil: car crush

    Microsoft Academic Search

    Eloy Martinez; David Tyrell; John Zolock

    2003-01-01

    Two grade-crossing impact tests were conducted in June 2002 at the Federal Railroad Administration's (FRA's) Transportation Technology Center in Pueblo, Colorado as part of the FRA's research into passenger equipment crashworthiness. In both of these tests a cab car moving at approximately 14 mph impacted a standing coil of steel supported by a frangible table. The coil was positioned such

  3. Mechanical modeling and analysis of the impact testing of wire

    Microsoft Academic Search

    G. Laird; K. K. Schrems

    1997-01-01

    A new experimental test method and its associated mechanics description is reported for the instrumented impact of small diameter rod and wire. The use of this test lies in its ability to quickly and effectively measure impact fracture energy at various dynamic strain rates while indirectly providing a measure of the material's dynamic yield stress. The basic outline of the

  4. A new impact erosion testing setup through Coriolis approach

    Microsoft Academic Search

    Harry H. Tian; Graeme R. Addie; Edward P. Barsh

    2007-01-01

    Coriolis wear testing is a valuable and practical approach to study the erosive wear of a material within a centrifugal slurry pump and other applicable systems. Impact wear mode is a significant component in erosive wear and simulation. Existing Coriolis erosion testers are primarily for evaluation of sliding wear. Although a few impact wear testing structures were previously proposed within

  5. The Impact of Courts on Teacher Competence Testing.

    ERIC Educational Resources Information Center

    D'Costa, Ayres G.

    1993-01-01

    Discusses how legal issues impinge upon teacher competency testing, describing key legal provisions (antitrust protection, due process, equal protection, substantial adverse impact, and business necessity), and examining each one's impact on testing and teacher certification. Recommendations to help teacher educators ensure legal, credible, and…

  6. Correlation between package-level ball impact test and board-level drop test

    Microsoft Academic Search

    Chang-Lin Yeh; Yi-Shao Lai; Hsiao-Chuan Chang; Tsan-Hsien Chen

    2005-01-01

    Package-level ball impact test and board-level drop test are performed and correlated empirically using a specific chip-scale package with solder joints of different Sn-Ag-Cu solder compositions. A positive correlation is found between characteristics of the impact force profile and reliability from the drop test, which provides a supporting basis for the package-level ball impact test to serve as a substitute

  7. Drop\\/impact simulation and test validation of telecommunication products

    Microsoft Academic Search

    Jason Wu; Guoshu Song; Chao-pin Yeh; Karl Wyatt

    1998-01-01

    Portable communication devices suffer impact-induced failure in usage. The products must pass drop\\/impact tests before shipment. The drop\\/impact performance is an important concern in product design. Due to the small size of this kind of electronic products, it is very expensive, time-consuming, and difficult to conduct drop tests to detect the failure mechanism and identify the drop behaviour. Finite element

  8. The Impact of Test Suite Granularity on the CostEffectiveness of Regression Testing

    E-print Network

    Rothermel, Gregg

    The Impact of Test Suite Granularity on the Cost­Effectiveness of Regression Testing Gregg,pkallakug@cse.unl.edu ABSTRACT Regression testing is an expensive testing process used to validate software following modifications. The cost­effective­ ness of regression testing techniques varies with characteris­ tics of test

  9. The Impact of Test Suite Granularity on the Cost-Effectiveness of Regression Testing

    E-print Network

    Rothermel, Gregg

    The Impact of Test Suite Granularity on the Cost-Effectiveness of Regression Testing Gregg,pkallakug@cse.unl.edu ABSTRACT Regression testing is an expensive testing process used to validate software following modi cations. The cost-e ective- ness of regression testing techniques varies with characteris- tics of test

  10. The Impact of Test Suite Granularity on the CostEffectiveness of Regression Testing

    E-print Network

    Rothermel, Gregg

    The Impact of Test Suite Granularity on the Cost­Effectiveness of Regression Testing Gregg,pkallakug@cse.unl.edu ABSTRACT Regression testing is an expensive testing process used to validate software following modi#12;cations. The cost-e#11;ective- ness of regression testing techniques varies with characteris- tics of test

  11. Study of the Impact Performance of Solder Joints by High-Velocity Impact Tests

    NASA Astrophysics Data System (ADS)

    Zhang, Ning; Shi, Yaowu; Guo, Fu; Yang, Fuqian

    2010-12-01

    The impact behavior of solder joints was studied using three different high-velocity impact tests: the U-notch Charpy impact test, the no-notch Charpy impact test, and a laboratory-designed drop test. The solder joints were made of five solder alloys, Sn-37Pb, Sn-3.8Ag-0.7Cu, Sn-2.0Ag-0.7Cu, Sn-1.0Ag-0.7Cu, and Sn-0.7Ag-0.7Cu (in wt.%), in which the traditional Cu/solder/Cu butt joint was used. All three impact tests gave the same trend of the impact behavior of the solder joints, with the Sn-37Pb joints having the highest impact resistance and the Sn-3.8Ag-0.7Cu joints having the lowest impact resistance. For the lead-free joints, the Sn-1.0Ag-0.7Cu joints had better impact resistance than the Sn-2.0Ag-0.7Cu joints, and the Sn-2.0Ag-0.7Cu joints better than the Sn-0.7Ag-0.7Cu joints. The impact behavior was correlated well to the fracture morphologies observed by scanning electron microscopy (SEM). Comparison of the three tests showed that the no-notch Charpy impact test is a promising method for evaluating the drop performance of solder joints.

  12. A critical assessment of the block impact test for measuring the impact strength of adhesive bonds

    Microsoft Academic Search

    J. A. Harris

    1996-01-01

    An analysis has been made of a commonly-used and widely-recommended impact test for adhesives, the Block Impact Test. It has been shown that this test has various limitations, related mainly to the difficulty in setting up the specimen and to the need to attach the impact apparatus rigidly to a stiff and heavy base.Finite element analysis has been used to

  13. Correlation studies for component level ball impact shear test and board level drop test

    Microsoft Academic Search

    E. H. Wong; Ranjan Rajoo; S. K. W. Seah; C. S. Selvanayagam; W. D. van Driel; J. F. J. M. Caers; X. J. Zhao; N. Owens; L. C. Tan; M. Leoni; P. L. Eu; Y.-S. Lai; C.-L. Yeh

    2008-01-01

    This paper presents a comprehensive study of the resistance of solder joints to failure when subjected to strain rates that simulate the conditions of drop-impact on a portable electronic product. Two test methods are used in this study: the board level drop\\/shock test (BLDT) and the component level ball impact shear test (BIST). The performance of (i) 12 material combinations

  14. Negative Impacts of High-Stakes Testing

    ERIC Educational Resources Information Center

    Minarechová, Michaela

    2012-01-01

    High-stakes testing is not a new phenomenon in education. It has become part of the education system in many countries. These tests affect the school systems, teachers, students, politicians and parents, whether that is in a positive or negative sense. High-stakes testing is associated with concepts such as a school's accountability, funding…

  15. Psychometric Impacts of Above-Level Testing

    E-print Network

    Warne, Russell Thomas

    2012-07-16

    to measure the middle levels of ability?where the majority of students? abilities lie?as effectively as possible (Lohman, 2005; Minnema, Thurlow, Bielinski, & Scott, 2000; Stanley, 1977). The emphasis that typical standardized tests place on average... researchers have used to test high ability children is called above- level testing (Stanley & Benbow, 1981-1982). Above-level testing is the procedure of administering a test to a gifted child who is younger or in a lower grade than the group for which...

  16. Agora: The Impact of High-Stakes Testing.

    ERIC Educational Resources Information Center

    O'Connell, P. J.; McGuire, C. Kent; Middleton, Richard; Thomas, Alicia; Ruiz, Richard; Bellamy, G. Thomas; Bornfield, Gail; Ohanian, Susan

    2000-01-01

    Eight members of the education community (e.g., students, teachers, college faculty, and administrators) respond to a question about the impact of high-stakes testing of teachers and students on teaching and teacher education. Their responses focus on such issues as test bias, at-risk students, specific state responses, and testing of students…

  17. Privacy Impact Assessment SAO MOSART Science Test Resource Registration

    E-print Network

    Mathis, Wayne N.

    Privacy Impact Assessment SAO MOSART Science Test Resource Registration I. System Identification 1. IT System Name: MOSART Science Test Resource Registration www.cfa.harvard.edu/smgphp/mosart 2. IT System: September 2009 8. Brief (one paragraph) description of the system: The MOSART Self Service Test Resource

  18. Assessing Individual-Level Impact of Interruptions during Online Testing

    ERIC Educational Resources Information Center

    Sinharay, Sandip; Wan, Ping; Choi, Seung W.; Kim, Dong-In

    2015-01-01

    With an increase in the number of online tests, the number of interruptions during testing due to unexpected technical issues seems to be on the rise. For example, interruptions occurred during several recent state tests. When interruptions occur, it is important to determine the extent of their impact on the examinees' scores. Researchers such as…

  19. Prototype impact tests on ultimate impact resistance of PC rock-sheds

    Microsoft Academic Search

    N. Kishi; H. Konno; K Ikeda; K. G Matsuoka

    2002-01-01

    To confirm the ultimate impact-resistant capacity of Prestressed Concrete (PC) rock-sheds constructed over the highways in Japan, prototype impact tests are conducted by using two types of PC rock-shed frames: inverted L frame and fully rigid frame. The two types are of equal dimensions: span length=10.1m, upper flange width=150cm, column height=4.65m. The impact tests are performed by iteratively and freely

  20. Low power arcjet test facility impacts

    NASA Technical Reports Server (NTRS)

    Morren, W. Earl; Lichon, Paul J.

    1992-01-01

    Performance characterization of a flight-type 1.4 kW arcjet system were conducted at the Rocket Research Company (RRC) in Redmond, WA, and at the NASA LeRC in Cleveland, OH. The objectives of these tests were as follows: to compare low-power arcjet performance at two different test facilities; to compare arcjet performance obtained with a 2:1 mixture of gaseous hydrogen and nitrogen and hydrazine; and to quantify the effects of test cell pressure on thruster operating characteristics. Performance and thruster temperature distributions were measured at thruster input power levels and propellant mass flow rates ranging from 1274 to 1370 W and from 3.2 x 10(exp -5) to 5.1 x 10(exp -5) kg/s, respectively. Specific impulses measured at the two facilities, at comparable test cell pressures, using gaseous hydrogen-nitrogen propellant mixtures agreed to within 1 percent over the range of operating conditions tested. The specific impulses measured using hydrazine propellant were higher than that for the cold hydrogen-nitrogen mixtures. Agreement between by hydrazine and gas mixture data was good, however, when the differences in propellant enthalpies at the thruster inlet were considered. Specific impulse showed a strong dependence on test facility pressure, and was 3 to 4 percent higher below 0.1 Pa than for test cell pressures above 5 Pa.

  1. Impact friction test method by applying stress wave

    Microsoft Academic Search

    K. Ogawa

    1997-01-01

    To understand the dynamic response of two bodies in contact, kinetic friction during impact presently is focused on. A new\\u000a testing technique, which provides the normal and the tangential impact force independently, is developed by modifying the\\u000a split Hopkinson pressure bar method. Normal and torsional stress wave propagation in a one-dimensional framework of an axial\\u000a impact of an input tube

  2. FEA of oblique impact tests on a motorcycle helmet

    Microsoft Academic Search

    N. J. Mills; S. Wilkes; S. Derler; A. Flisch

    2009-01-01

    In accidents, motorcycle riders full-face helmets often make oblique impacts with road surfaces. Finite element analysis was used to predict the rotational and linear acceleration of a Hybrid II headform, representing a motorcyclist's head, in such impacts, considering the effects of friction at the head\\/helmet and helmet\\/road interfaces. Simulations of the oblique impact test in British Standard BS 6658 were

  3. LLNL small-scale drop-hammer impact sensitivity test

    SciTech Connect

    Simpson, L.R.; Foltz, M.F.

    1995-01-01

    Small-scale safety testing of explosives and other energetic materials is done to determine their sensitivity to various stimuli including friction, static spark, and impact. This testing is typically done to discover potential handling problems for either newly synthesized materials of unknown behavior or materials that have been stored for long periods of time. This report describes the existing ``ERL Type 12 Drop Weight Impact Sensitivity Apparatus``, or ``Drop Hammer Machine``, and the methods used to determine the impact sensitivity of energetic materials, Also discussed are changes made to both the machine and methods since the inception of impact sensitivity testing at LLNL in 1956. The accumulated data for the materials tested in not listed here, the exception being the discussion of those specific materials (primary calibrants: PETN, RDX, Comp-B3,and TNT; secondary calibrants: K-6, RX-26-AF, and TATB) used to calibrate the machine.

  4. Low-power arcjet test facility impacts

    NASA Technical Reports Server (NTRS)

    Morren, W. E.; Lichon, Paul J.

    1992-01-01

    Performance characterizations of a flight-type 1.4 kW arcjet system were conducted. Performance and thruster temperature distributions were measured at thruster input power levels and propellant mass flow rates ranging from 1274 to 1370 W and from 3.2 x 10 exp -5 to 5.1 x 10 exp -5 kg/s, respectively. Specific impulses measured at the two facilities, at comparable test cell pressures, using gaseous hydrogen-nitrogen propellant mixtures agreed to within 1 percent over the range of operating conditions tested. The specific impulses measured using hydrazine propellant were higher than that for the cold hydrogen/nitrogen mixtures. Agreement between the hydrazine and gas mixture data was good, however, when the differences in propellant ethalpies at the thruster inlet were considered. Specific impulse showed a strong dependence on test facility pressure, and was 3 to 4 percent higher below 0.1 Pa than for test cell pressures above 5 Pa.

  5. Live fire testing requirements - Assessing the impact

    SciTech Connect

    O'Bryon, J.F. (DOD, Office of the Secretary of Defense, Washington, DC (United States))

    1992-08-01

    Full-up live-fire testing (LFT) of aircraft configured for combat is evaluated in terms of the practical implications of the technique. LFT legislation requires the testing of tactical fighters, helicopters, and other aircraft when they are loaded with the flammables and explosives associated with combat. LFT permits the study of damage mechanisms and battle-damage repair techniques during the design phase, and probability-of-kill estimates and novel systems designs can be developed based on LFT data.

  6. Taylor impact tests and simulations of plastic bonded explosives

    NASA Astrophysics Data System (ADS)

    Clements, Brad E.; Thompson, Darla; Luscher, D. J.; DeLuca, Racci; Brown, Geoffrey

    2012-03-01

    Taylor impact tests were conducted on plastic bonded explosives PBX 9501 and PBXN-9 for impact velocities between 80 and 214 m/s. High-speed photography was used to image the impact event at a rate of one frame for every 25 ?s. For early times, PBXN-9 showed large-deformation mushrooming of the explosive cylinders, followed by fragmentation by an amount proportional to the impact speed, was observed at all velocities. PBX 9501 appeared to be more brittle than PBXN-9, the latter demonstrated a more viscoelastic response. The post-shot fragments were collected and particle size distributions were obtained. The constitutive model ViscoSCRAM was then used to model the Taylor experiments using the finite element code ABAQUS. Prior to the Taylor simulations, ViscoSCRAM was parameterized for the two explosives using uniaxial stress-strain data. Simulating Taylor impact tests validates the model in situations undergoing extreme damage and fragmentation.

  7. Impact Testing and Simulation of Composite Airframe Structures

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Littell, Justin D.; Horta, Lucas G.; Annett, Martin S.; Fasanella, Edwin L.; Seal, Michael D., II

    2014-01-01

    Dynamic tests were performed at NASA Langley Research Center on composite airframe structural components of increasing complexity to evaluate their energy absorption behavior when subjected to impact loading. A second objective was to assess the capabilities of predicting the dynamic response of composite airframe structures, including damage initiation and progression, using a state-of-the-art nonlinear, explicit transient dynamic finite element code, LS-DYNA. The test specimens were extracted from a previously tested composite prototype fuselage section developed and manufactured by Sikorsky Aircraft Corporation under the US Army's Survivable Affordable Repairable Airframe Program (SARAP). Laminate characterization testing was conducted in tension and compression. In addition, dynamic impact tests were performed on several components, including I-beams, T-sections, and cruciform sections. Finally, tests were conducted on two full-scale components including a subfloor section and a framed fuselage section. These tests included a modal vibration and longitudinal impact test of the subfloor section and a quasi-static, modal vibration, and vertical drop test of the framed fuselage section. Most of the test articles were manufactured of graphite unidirectional tape composite with a thermoplastic resin system. However, the framed fuselage section was constructed primarily of a plain weave graphite fabric material with a thermoset resin system. Test data were collected from instrumentation such as accelerometers and strain gages and from full-field photogrammetry.

  8. Marshall Space Flight Center's Impact Testing Facility Capabilities

    NASA Technical Reports Server (NTRS)

    Finchum, Andy; Hubbs, Whitney; Evans, Steve

    2008-01-01

    Marshall Space Flight Center s (MSFC) Impact Testing Facility (ITF) serves as an important installation for space and missile related materials science research. The ITF was established and began its research in spacecraft debris shielding in the early 1960s, then played a major role in the International Space Station debris shield development. As NASA became more interested in launch debris and in-flight impact concerns, the ITF grew to include research in a variety of impact genres. Collaborative partnerships with the DoD led to a wider range of impact capabilities being relocated to MSFC as a result of the closure of Particle Impact Facilities in Santa Barbara, California. The Particle Impact Facility had a 30 year history in providing evaluations of aerospace materials and components during flights through rain, ice, and solid particle environments at subsonic through hypersonic velocities. The facility s unique capabilities were deemed a "National Asset" by the DoD. The ITF now has capabilities including environmental, ballistic, and hypervelocity impact testing utilizing an array of air, powder, and two-stage light gas guns to accommodate a variety of projectile and target types and sizes. Numerous upgrades including new instrumentation, triggering circuitry, high speed photography, and optimized sabot designs have been implemented. Other recent research has included rain drop demise characterization tests to obtain data for inclusion in on-going model development. The current and proposed ITF capabilities range from rain to micrometeoroids allowing the widest test parameter range possible for materials investigations in support of space, atmospheric, and ground environments. These test capabilities including hydrometeor, single/multi-particle, ballistic gas guns, exploding wire gun, and light gas guns combined with Smooth Particle Hydrodynamics Code (SPHC) simulations represent the widest range of impact test capabilities in the country.

  9. Impact tests of reinforced plastics at low temperatures

    Microsoft Academic Search

    S. Nishijimo; S. Namba; T. Okada; M. Takeno

    1982-01-01

    The applied forces to the component materials of a superconducting magnet take on varied and complex forms with an increase in magnet size and pulsative mode of operation. This study records the procedures and results of Charpy impact and drop weight tests performed on reinforced plastics that have such applicatons. The sample specifications are given; the tests were performed at

  10. Data analysis techniques for impact tests of composite materials

    Microsoft Academic Search

    A. L. Svenson; M. W. Hargrave; B. S. Ye; L. C. Bank

    1994-01-01

    This paper discusses data analysis techniques for instrumented impact tests conducted on glass fiber composite materials. For this study, a drop weight tower has been instrumented with an accelerometer and computer data acquisition system. From the acceleration data obtained, load, energy, velocity, and displacement are calculated in a spreadsheet environment. The resulting data from multiple tests for each material type

  11. Impact Testing of Stainless Steel Material at Cold Temperatures

    SciTech Connect

    Spencer D. Snow; D. Keith Morton; Robert K. Blandford

    2008-07-01

    Stainless steels are used for the construction of numerous spent nuclear fuel or radioactive material containers that may be subjected to high strains and moderate strain rates during accidental drop events. Mechanical characteristics of these base materials and their welds under dynamic loads in the strain rate range of concern are not well documented. However, a previous paper [1] reported on impact testing and analysis results performed at the Idaho National Laboratory using 304/304L and 316/316L stainless steel base material specimens at room and elevated temperatures. The goal of the work presented herein is to add recently completed impact tensile testing results at -20 degrees F conditions for dual-marked 304/304L and 316/316L stainless steel material specimens (hereafter referred to as 304L and 316L, respectively). Recently completed welded material impact testing at -20 degrees F, room, 300 degrees F, and 600 degrees F is also reported. Utilizing a drop-weight impact test machine and 1/4-inch to 1/2-inch thick dog-bone shaped test specimens, the impact tests achieved strain rates in the 4 to 40 per second range, depending upon the material temperature. Elevated true stress-strain curves for these materials reflecting varying strain rates and temperatures are presented herein.

  12. Evaluation of solder joint strengths under ball impact test

    Microsoft Academic Search

    Yi-Shao Lai; Hsiao-Chuan Chang; Chang-Lin Yeh

    2007-01-01

    The ball impact test (BIT) was developed based on the demand of a package-level measure of the board-level reliability of solder joints in the sense that it leads to brittle intermetallic fracturing, similar to that from a board-level drop test. The BIT itself stands alone as a unique and novel test methodology in characterizing strengths of solder joints under a

  13. Impact testing of centrifugally cast canisters of simulated waste glass

    SciTech Connect

    Peterson, M.E.; Alzheimer, J.M.

    1984-10-01

    Four simulated high-level waste canisters supplied by EG and G Idaho, Inc. of Idaho Falls, Idaho, were subjected to impact tests at the Pacific Northwest Laboratory in Richland, Washington. The canister design was similar to the most recent Savannah River Laboratory (SRL) reference dewsign for the Defense Waste Processing Facility. Three of the canister bodies were fabricated out of a special cast alloy (the centrifugally cast equivalent of 304L stainless steel). These were nonradioactive versions of canisters that can be fabricated by recycling slightly contaminated stainless steel. A canister of wrought 304L stainless steel was also tested as a control. The canisters were filled with a borosilicate glass at SRL. The purpose of the test was to evaluate the effect of impacts on the canisters and provide input for a study to determine if slightly contaminated metal could be used for waste disposal canisters. Each canister was subjected to three impacts. The first was a vertical drop from 30 ft onto an unyielding surface with the bottom corner of the canister receiving the impact. The second was a horizontal drop from 40 in. onto a solid steel vertical cylinder (6 in. dia x 14 in. long) in a puncture test. The final drop was from 30 ft onto an unyielding surface with the fill nozzle and head receiving the impact. No rupturing of any of the canisters occurred as a result of the impacts. Strain circles were used to measure the surface strain in the impact areas. The maximum tensile strain experienced was 13% and the maximum compressive strain experienced was 16%. These measured strains were below the minimum strain required for failure, which is at least 30%. A helium leak test and liquid dye penetrant test were conducted on the weld regions of these canisters after the drop to evaluate the condition of the canister. No leaks were detected and no significant indications of cracks appeared. 2 references, 39 figures.

  14. Low velocity impact and compression after impact tests on thin carbon\\/epoxy laminates

    Microsoft Academic Search

    Daniele Ghelli; Giangiacomo Minak

    2011-01-01

    The results of drop-weight impact tests and compression after impact (CAI) tests on carbon\\/epoxy laminates are presented. The experiments were carried out on specimens of two different geometries (rectangular and circular), according to two ASTM standards. Laminates of small thickness, thus prone to buckling under compression, were considered. Two different quasi-isotropic stacking sequences, obtained by cutting the specimens in two

  15. Rail car impact tests with steel coil: collision dynamics

    Microsoft Academic Search

    K. Jacobsen; D. Tyrell; B. Perlman

    2003-01-01

    Two full-scale oblique grade-crossing impact tests were conducted in June 2002 to compare the crashworthiness performance of alternative corner post designs on rail passenger cab cars. On June 4, 2002 a cab car fitted with an end structure built to pre-1999 requirements impacted a steel coil at approximately 14 mph. Following, on June 7, 2002 a cab car fitted with

  16. Marshall Space Flight Center's Impact Testing Facility Capabilities

    NASA Technical Reports Server (NTRS)

    Evans, Steve; Finchum, Andy; Hubbs, Whitney

    2008-01-01

    Marshall Space Flight Center's (MSFC) Impact Testing Facility (ITF) serves as an important installation for space and missile related materials science research. The ITF was established and began its research in spacecraft debris shielding in the early 1960% then played a major role in the International Space Station debris shield development. As NASA became more interested in launch debris and in-flight impact concerns, the ITF grew to include research in a variety of impact genres. Collaborative partnerships with the DoD led to a wider range of impact capabilities being relocated to MSFC as a result of the closure of Particle Impact Facilities in Santa Barbara, California. The Particle Impact Facility had a 30 year history in providing evaluations of aerospace materials and components during flights through rain, ice, and solid particle environments at subsonic through hypersonic velocities. The facility's unique capabilities were deemed a "National Asset" by the DoD. The ITF now has capabilities including environmental, ballistic, and hypervelocity impact testing utilizing an array of air, powder, and two-stage light gas guns to accommodate a variety of projectile and target types and sizes. Relocated test equipment was dated and in need of upgrade. Numerous upgrades including new instrumentation, triggering circuitry, high speed photography, and optimized sabot designs have been implemented. Other recent research has included rain drop demise characterization tests to obtain data for inclusion in on-going model development. Future ITF improvements will be focused on continued instrumentation and performance enhancements. These enhancements will allow further, more in-depth, characterization of rain drop demise characterization and evaluation of ice crystal impact. Performance enhancements also include increasing the upper velocity limit of the current environmental guns to allow direct environmental simulation for missile components. The current and proposed ITF capabilities range from rain to micrometeoroids allowing the widest test parameter range possible for materials investigations in support of space, atmospheric, and ground environments. These test capabilities including hydrometeor, single/multi-particle, ballistic gas grins, exploding wire gun, and light gas guns combined with Smooth Particle Hydrodynamics Code (SPHC) simulations represent the widest range of impact test capabilities in the country.

  17. Marshall Space Flight Center's Impact Testing Facility Capabilities

    NASA Technical Reports Server (NTRS)

    Evans, Steve; Finchum, Andy; Hubbs, Whitney; Gray, Perry

    2008-01-01

    Marshall Space Flight Center's (MSFC) Impact Testing Facility (ITF) serves as an important installation for space and missile related materials science research. The ITF was established and began its research in spacecraft debris shielding in the early 1960s, then played a major role in the International Space Station debris shield development. As NASA became more interested in launch debris and in-flight impact concerns, the ITF grew to include research in a variety of impact genres. Collaborative partnerships with the DoD led to a wider range of impact capabilities being relocated to MSFC as a result of the closure of Particle Impact Facilities in Santa Barbara, California, The Particle Impact Facility had a 30 year history in providing evaluations of aerospace materials and components during flights through rain, ice, and solid particle environments at subsonic through hypersonic velocities. The facility's unique capabilities were deemed a 'National Asset' by the DoD, The ITF now has capabilities including environmental, ballistic, and hypervelocity impact testing utilizing an array of air, powder, and two-stage light gas guns to accommodate a variety of projectile and target types and sizes. Relocated test equipment was dated and in need of upgrade. Numerous upgrades including new instrumentation, triggering circuitry, high speed photography, and optimized sabot designs have been implemented. Other recent research has included rain drop demise characterization tests to obtain data for inclusion in on-going model development. Future ITF improvements will be focused on continued instrumentation and performance enhancements. These enhancements will allow further, more in-depth, characterization of rain drop demise characterization and evaluation of ice crystal impact. Performance enhancements also include increasing the upper velocity limit of the current environmental guns to allow direct environmental simulation for missile components. The current and proposed ITF capabilities range from rain to micrometeoroids allowing the widest test parameter range possible for materials investigations in support of space, atmospheric, and ground environments. These test capabilities including hydrometeor, single/multi-particle, ballistic gas guns, exploding wire gun, and light gas guns combined with Smooth Particle Hydrodynamics Code (SPHC) simulations represent the widest range of impact test capabilities in the country.

  18. Neural Networks Analyze Data In Particle-Impact-Noise Tests

    NASA Technical Reports Server (NTRS)

    Scaglione, Lois J.

    1995-01-01

    Electronic neural networks and computers put to use in analyzing data acquired in particle-impact-noise-detection (PIND) tests of packaged electronic components. PIND tests detect loose particles in packages that cause failures during subsequent operation of packages in presence of accelerations or other effects - for example, loose electrically conductive particles that bounce into positions in which they cause short circuits. Interpretation of test data more objective and accurate. Preliminary results suggest use of neural networks result in significant improvement in quality and reliability and decrease in cost of PIND testing.

  19. Impact limiter tests of four commonly used materials and establishment of an impact limiter data base

    SciTech Connect

    McMurtry, W.M.; Hohnstreiter, G.F.

    1995-12-31

    In designing a package for transporting hazardous or radioactive materials, there are a number of components whose design can lead to the success or failure to meet regulatory requirements for Type B packages. One of these components is the impact limiter. The primary purpose of the impact limiter is to protect the package and its contents from sudden deceleration. It can also act as a thermal barrier. The package is protected by the impact limiter`s ability to act as an energy absorber. The crush strength of most impact limiting materials is determined by a standard quasistatic (QS) method. However it has been observed that there are a number of factors that affect crush strength. The material being used as an impact limiter may appear incompressible because of one or more of these factors. Factors that determine compressive strength of impact limiter materials are; the material density; the thickness of the impact limiter material. There must be adequate material to absorb the impact and not go into lockup, lockup up occurs when the free volume of the material is eliminated and the crush strength sharply increases; the angle of impact; and the loading rate and operating temperature. All of these are interactive and therefore difficult to model. It is the intent of tests discussed in this paper to determine the dependency of crush strength to loading rate and angle of impact to the basic grain direction of two different densities of four impact limiting materials.

  20. Effect of aging on impact properties of ASTM A890 Grade 1C super duplex stainless steel

    SciTech Connect

    Martins, Marcelo [Industrial Manager of SULZER BRASIL S/A and Professor of the Centro Universitario Salesiano de Sao Paulo (UNISAL) at Americana, SP (Brazil)], E-mail: marcelo.martins@sulzer.com; Forti, Leonardo Rodrigues Nogueira [Materials Engineer at UFSCar, Federal University of Sao Carlos (Brazil)], E-mail: leornf@yahoo.com.br

    2008-02-15

    Super duplex stainless steels in the solution annealed condition are thermodynamically metastable systems which, when exposed to heat, present a strong tendency to 'seek' the most favorable thermodynamic condition. The main purpose of this study was to characterize the microstructure of a super duplex stainless steel in the as cast and solution annealed conditions, and to determine the influence of aging heat treatments on its impact strength, based on Charpy impact tests applied to V-notched test specimens. The sigma phase was found to begin precipitating at heat treatment temperatures above 760 deg. C and to dissolve completely only above 1040 deg. C, with the highest peak concentration of this phase appearing at close to 850 deg. C. Heat treatments conducted at temperatures of 580 deg. C to 740 deg. C led to a reduction of the energy absorbed in the Charpy impact test in response to the precipitation of a particulate phase with particle sizes ranging from 0.5 {mu}m to 1.0 {mu}m, with a chromium and iron-rich chemical composition.

  1. Large Field Photogrammetry Techniques in Aircraft and Spacecraft Impact Testing

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.

    2010-01-01

    The Landing and Impact Research Facility (LandIR) at NASA Langley Research Center is a 240 ft. high A-frame structure which is used for full-scale crash testing of aircraft and rotorcraft vehicles. Because the LandIR provides a unique capability to introduce impact velocities in the forward and vertical directions, it is also serving as the facility for landing tests on full-scale and sub-scale Orion spacecraft mass simulators. Recently, a three-dimensional photogrammetry system was acquired to assist with the gathering of vehicle flight data before, throughout and after the impact. This data provides the basis for the post-test analysis and data reduction. Experimental setups for pendulum swing tests on vehicles having both forward and vertical velocities can extend to 50 x 50 x 50 foot cubes, while weather, vehicle geometry, and other constraints make each experimental setup unique to each test. This paper will discuss the specific calibration techniques for large fields of views, camera and lens selection, data processing, as well as best practice techniques learned from using the large field of view photogrammetry on a multitude of crash and landing test scenarios unique to the LandIR.

  2. End-on radioisotope thermoelectric generator impact tests

    SciTech Connect

    Reimus, M.A.H.; Hhinckley, J.E.

    1997-01-01

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of [sup 238]Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). The modular GPHS design was developed to address both survivability during launch abort and return from orbit. The first two RTG Impact Tests were designed to provide information on the response of a fully loaded RTG to end-on impact against a concrete target. The results of these tests indicated that at impact velocities up to 57 m/s the converter shell and internal components protect the GPHS capsules from excessive deformation. At higher velocities, some of the internal components of the RTG interact with the GPHS capsules to cause excessive localized deformation and failure.

  3. End-on radioisotope thermoelectric generator impact tests

    SciTech Connect

    Reimus, M.A.; Hinckley, J.E. [Los Alamos National Laboratory P.O. Box 1663, MS-E502 Los Alamos, New Mexico87545 (United States)

    1997-01-01

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). The modular GPHS design was developed to address both survivability during launch abort and return from orbit. The first two RTG Impact Tests were designed to provide information on the response of a fully loaded RTG to end-on impact against a concrete target. The results of these tests indicated that at impact velocities up to 57 m/s the converter shell and internal components protect the GPHS capsules from excessive deformation. At higher velocities, some of the internal components of the RTG interact with the GPHS capsules to cause excessive localized deformation and failure. {copyright} {ital 1997 American Institute of Physics.}

  4. Address and Data Scrambling: Causes and Impact on Memory Tests

    Microsoft Academic Search

    A. J. Van De Goor; Ivo Schanstra

    2002-01-01

    The way address sequences and data patterns appear on the outside of a memory may differ from their in- ternal appearance; this effect is referred to asscrambling, which has a large impact on the effectiveness of the used tests. This paper presents an analysis of address and data scrambling for memory chips, at the layout and at the elec- trical

  5. Low velocity impact testing and nondestructive evaluation of transparent materials

    SciTech Connect

    Brennan, R. E.; Green, W. H. [U.S. Army Research Laboratory, 4600 Deer Creek Loop, Aberdeen Proving Ground, MD 21005-5066 (United States)

    2011-06-23

    Advanced transparent materials are used in protective systems for enhancing the survivability of ground vehicles, air vehicles, and personnel in applications such as face shields, riot gear, and vehicle windows. Low velocity impact damage can limit visibility and compromise the structural integrity of a transparent system, increasing the likelihood of further damage or penetration from a high velocity impact strike. For this reason, it is critical to determine damage tolerance levels of transparent systems to indicate whether or not a component should be replaced. In this study, transparent laminate systems will be tested by comparing baseline conditions to experimentally controlled damage states. Destructive testing including air gun and sphere impact testing will be used to replicate low velocity impacts in the field. Characterization of the damaged state will include basic visual inspection as well as nondestructive techniques including cross-polarization, x-ray, and ultrasound. The combination of destructive testing and characterization of the resulting damage can help to establish a damage acceptance criterion for materials used in protective systems.

  6. Analysis-test correlation of airbag impact for Mars landing

    SciTech Connect

    Salama, M.; Davis, G.; Kuo, C.P. [and others

    1994-12-31

    The NASA Mars Pathfinder mission is intended to demonstrate key low cost technologies for use in future science missions to Mars. Among these technologies is the landing system. Upon entering in Martian atmosphere at about 7000 m/sec., the spacecraft will deploy a series of breaking devices (parachute and solid rockets) to slow down its speed to less than 20 m/sec. as it impacts with the Martian ground. To cushion science instruments form the landing impact, an airbag system is inflated to surround the lander approximately five seconds before impact. After multiple bounces, the lander/airbags comes to rest, the airbags are deflated and retracted, and the lander opens up its petals to allow a microrover to begin exploration. Of interest here, is the final landing phase. Specifically, this paper will focus on the methodology used to simulate the nonlinear dynamics of lander/airbags landing impact, and how this simulation correlates with initial tests.

  7. Sloshing roof impact tests of a rectangular tank

    SciTech Connect

    Minowa, C.; Ogawa, N. [National Research Inst., for Earth Science and Disaster Prevention, Tusukuba, Ibaraki (Japan); Harada, I. [Bridgestone Corp., Yokohama, (Japan); Ma, D.C. [Argonne National Lab., IL (United States)

    1994-06-01

    Some tanks have been damaged at the roofs due to sloshing impact caused by strong earthquakes. It is, therefore, necessary to consider the impact force in the aseismic design code for tank roofs. However, there are few studies on the earthquake responses of storage and process tank roofs. As a first step to investigate the effects of sloshing impact a series of the shaking table tests of a rectangular tank have been conducted at the National Research Institute for Earth Science and Disaster Prevention (NIED). The results of these shaking table tests are presented in the paper. The test tank is rectangular in shape having dimensions of 5 m {times} 3 m {times} 2 m length {times} width {times} height). The tank was constructed of glass-fiber reinforced plastic panels. Every panel had a flange on four edges, and each panel was connected by bolts along the flange. The test tank was set on the NIED shaking table (15 m by 15 m). Two types of liquid were used, water and a viscous liquid (water mixed with polymeric powders). The roof impact pressures and other quantities were measured. During the tests using the 400 pi El-Centro excitation, the roof deformation sensor steel beam was damaged. The response of side walls with different rigidity were measured in the wall bulging tests. The measured vibrations within the panel plates were larger than those in the panel flanges. The viscous liquid of 100 cp had little influence on wall bulging responses. However, the viscous effects on sloshing responses were observed in the sloshing tests. Approximate analyses of rectangular tanks, considering the influence of static water pressure, are also presented in this paper.

  8. Repeated drop weight impacts and post-impact ILSS tests on glass-epoxy composite

    Microsoft Academic Search

    Kishore; S Ramanathan; RMVGK Rao

    1996-01-01

    E glass epoxy laminates of thicknesses in the range 2–5 mm were subjected to repeated impacts. For each thickness the number\\u000a of hits to cause tup penetration was determined and the value of this number was higher the larger the thickness of the laminate\\u000a tested. The C-scan, before and after impact, was done to obtain information regarding flaw distribution. Short

  9. Using Simulation for Assessing the Real Impact of Test Coverage on Defect Lionel C. Briand

    E-print Network

    Carleton University

    Using Simulation for Assessing the Real Impact of Test Coverage on Defect Coverage Lionel C. Briand additional impact on defect coverage when compared to the impact of just running additional test cases Engineering, Kaiserslautern, Germany Key Words - Software test, Test coverage, Defect coverage, Test intensity

  10. 46 CFR 54.05-20 - Impact test properties for service of 0 °F and below.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 false Impact test properties for service of 0 Â...GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Toughness Tests § 54.05-20 Impact test properties for service of...

  11. 46 CFR 54.05-20 - Impact test properties for service of 0 °F and below.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 false Impact test properties for service of 0 Â...GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Toughness Tests § 54.05-20 Impact test properties for service of...

  12. 46 CFR 54.05-20 - Impact test properties for service of 0 °F and below.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 false Impact test properties for service of 0 Â...GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Toughness Tests § 54.05-20 Impact test properties for service of...

  13. 46 CFR 54.05-20 - Impact test properties for service of 0 °F and below.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Impact test properties for service of 0 Â...GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PRESSURE VESSELS Toughness Tests § 54.05-20 Impact test properties for service of...

  14. Program for impact testing of spar-shell fan blades, test report

    NASA Technical Reports Server (NTRS)

    Ravenhall, R.; Salemme, C. T.

    1978-01-01

    Six filament-wound, composite spar-shell fan blades were impact tested in a whirligig relative to foreign object damage resulting from ingestion of birds into the fan blades of a QCSEE-type engine. Four of the blades were tested by injecting a simulated two pound bird into the path of the rotating blade and two were tested by injecting a starling into the path of the blade.

  15. Space Shuttle Main Engine Debris Testing Methodology and Impact Tolerances

    NASA Technical Reports Server (NTRS)

    Gradl, Paul R.; Stephens, Walter

    2005-01-01

    In the wake of the Space Shuttle Columbia disaster every effort is being made to determine the susceptibility of Space Shuttle elements to debris impacts. Ice and frost debris is formed around the aft heat shield closure of the orbiter and liquid hydrogen feedlines. This debris has been observed to liberate upon lift-off of the shuttle and presents potentially dangerous conditions to the Space Shuttle Main Engine. This paper describes the testing done to determine the impact tolerance of the Space Shuttle Main Engine nozzle coolant tubes to ice strikes originating from the launch pad or other parts of the shuttle.

  16. Hypervelocity Impact Test Facility: A gun for hire

    NASA Technical Reports Server (NTRS)

    Johnson, Calvin R.; Rose, M. F.; Hill, D. C.; Best, S.; Chaloupka, T.; Crawford, G.; Crumpler, M.; Stephens, B.

    1994-01-01

    An affordable technique has been developed to duplicate the types of impacts observed on spacecraft, including the Shuttle, by use of a certified Hypervelocity Impact Facility (HIF) which propels particulates using capacitor driven electric gun techniques. The fully operational facility provides a flux of particles in the 10-100 micron diameter range with a velocity distribution covering the space debris and interplanetary dust particle environment. HIF measurements of particle size, composition, impact angle and velocity distribution indicate that such parameters can be controlled in a specified, tailored test designed for or by the user. Unique diagnostics enable researchers to fully describe the impact for evaluating the 'targets' under full power or load. Users regularly evaluate space hardware, including solar cells, coatings, and materials, exposing selected portions of space-qualified items to a wide range of impact events and environmental conditions. Benefits include corroboration of data obtained from impact events, flight simulation of designs, accelerated aging of systems, and development of manufacturing techniques.

  17. High-pressure oxygen test evaluations. [impact tests/metals - space shuttles

    NASA Technical Reports Server (NTRS)

    Schwinghamer, R. J.; Key, C. F.

    1974-01-01

    The relevance of impact sensitivity testing to the development of the space shuttle main engine is discussed in the light of the special requirements for the engine. The background and history of the evolution of liquid and gaseous oxygen testing techniques and philosophy is discussed also. The parameters critical to reliable testing are treated in considerable detail, and test apparatus and procedures are described and discussed. Materials threshold sensitivity determination procedures are considered and a decision logic diagram for sensitivity threshold determination was plotted. Finally, high-pressure materials sensitivity test data are given for selected metallic and nonmetallic materials.

  18. Penetration tests on the DS-2 Mars microprobes: penetration depth and impact accelerometry

    E-print Network

    Lorenz, Ralph D.

    Penetration tests on the DS-2 Mars microprobes: penetration depth and impact accelerometry Ralph D; accepted 16 August 1999 Abstract We describe the results of three separate sets of impact tests conducted describe three sets of impact test and their results regarding impact accelerometer data and penetration

  19. Radioisotope thermoelectric generator/thin fragment impact test

    SciTech Connect

    Reimus, M. A. H.; Hinckley, J. E. [Los Alamos National Laboratory, P.O. Box 1663, MS-E502, Los Alamos, New Mexico 87545 (United States)

    1998-01-15

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). Because the potential for a launch abort or return from orbit exists for any space mission, the heat source response to credible accident scenarios is being evaluated. This test was designed to provide information on the response of a loaded RTG to impact by a fragment similar to the type of fragment produced by breakup of the spacecraft propulsion module system (PMS). The results of this test indicated that impact of the RTG by a thin aluminum fragment traveling at 306 m/s may result in significant damage to the converter housing, failure of one fueled clad, and release of a small quantity of fuel.

  20. Radioisotope thermoelectric generator/thin fragment impact test

    SciTech Connect

    Reimus, M.A.; Hinckley, J.E. [Los Alamos National Laboratory, P.O. Box 1663, MS-E502, Los Alamos, New Mexico 87545 (United States)

    1998-01-01

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). Because the potential for a launch abort or return from orbit exists for any space mission, the heat source response to credible accident scenarios is being evaluated. This test was designed to provide information on the response of a loaded RTG to impact by a fragment similar to the type of fragment produced by breakup of the spacecraft propulsion module system (PMS). The results of this test indicated that impact of the RTG by a thin aluminum fragment traveling at 306 m/s may result in significant damage to the converter housing, failure of one fueled clad, and release of a small quantity of fuel. {copyright} {ital 1998 American Institute of Physics.}

  1. Radioisotope thermoelectric generator/thin fragment impact test

    SciTech Connect

    Reimus, M.A.H.; Hinckley, J.E.

    1998-12-31

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). Because the potential for a launch abort or return from orbit exists for any space mission, the heat source response to credible accident scenarios is being evaluated. This test was designed to provide information on the response of a loaded RTG to impact by a fragment similar to the type of fragment produced by breakup of the spacecraft propulsion module system (PMS). The results of this test indicated that impact of the RTG by a thin aluminum fragment traveling at 306 m/s may result in significant damage to the convertor housing, failure of one fueled clad, and release of a small quantity of fuel.

  2. Estimating the Impacts of Educational Interventions Using State Tests or Study-Administered Tests. NCEE 2012-4016

    ERIC Educational Resources Information Center

    Olsen, Robert B.; Unlu, Fatih; Price, Cristofer; Jaciw, Andrew P.

    2011-01-01

    This report examines the differences in impact estimates and standard errors that arise when these are derived using state achievement tests only (as pre-tests and post-tests), study-administered tests only, or some combination of state- and study-administered tests. State tests may yield different evaluation results relative to a test that is…

  3. Impact Testing on Composites Laminates and Sandwich Panels

    Microsoft Academic Search

    Claudio Scarponi; Giuseppe Briotti; Renato Barboni; Antonio Marcone; Michele Iannone

    1996-01-01

    The purpose of this work was the evaluation of the behavior of fiber-reinforced composites and sandwich panels for aeronautical applications under impact.Experimental tests were performed on several specimen configurations, based on different quasi-isotropic lay-up and materials such CFRP, CFRTP and a syntactic foam as the core of sandwich panels. Considering the high specific mechanics characteristics of such a foam and

  4. West Valley Demonstration Project full-scale canister impact tests

    SciTech Connect

    Whittington, K.F.; Alzheimer, J.M. [Pacific Northwest Lab., Richland, WA (United States); Lutz, C.E. [West Valley Nuclear Services, West Valley, NY (United States)

    1995-09-01

    Five West Valley Nuclear Services (WVNS) high-level waste (HLW) canisters were impact tested during 1994 to demonstrate compliance with the drop test requirements of the Waste Acceptance Product Specifications. The specifications state that the canistered waste form must be able to survive a 7{minus}m (23 ft) drop unbreached. The 10-gauge (0.125 in. wall thickness) stainless steel canisters were approximately 85% filled with simulated vitrified waste and weighed about 2100 kg (4600 lb). Each canister was dropped vertically from a height of 7 m (23 ft) onto an essentially unyielding surface. The integrity of the canister was determined by the application and analysis of strain circles, dimensional measurements, and helium leak testing. The canisters were also visually inspected before and after the drop for physical damage. The results of the impact test verify that the canisters survived the 7{minus}m drops unbreached. Therefore, these results demonstrate that the reference canister meets the drop test specification of the Waste Acceptance Product Specification.

  5. Arcjet Testing of Micro-Meteoroid Impacted Thermal Protection Materials

    NASA Technical Reports Server (NTRS)

    Agrawal, Parul; Munk, Michelle M.; Glaab, Louis J.

    2013-01-01

    There are several harsh space environments that could affect thermal protection systems and in turn pose risks to the atmospheric entry vehicles. These environments include micrometeoroid impact, extreme cold temperatures, and ionizing radiation during deep space cruise, all followed by atmospheric entry heating. To mitigate these risks, different thermal protection material samples were subjected to multiple tests, including hyper velocity impact, cold soak, irradiation, and arcjet testing, at various NASA facilities that simulated these environments. The materials included a variety of honeycomb packed ablative materials as well as carbon-based non-ablative thermal protection systems. The present paper describes the results of the multiple test campaign with a focus on arcjet testing of thermal protection materials. The tests showed promising results for ablative materials. However, the carbon-based non-ablative system presented some concerns regarding the potential risks to an entry vehicle. This study provides valuable information regarding the capability of various thermal protection materials to withstand harsh space environments, which is critical to sample return and planetary entry missions.

  6. A semiautomated computer-interactive dynamic impact testing system

    SciTech Connect

    Alexander, D.J.; Nanstad, R.K.; Corwin, W.R.; Hutton, J.T.

    1989-01-01

    A computer-assisted semiautomated system has been developed for testing a variety of specimen types under dynamic impact conditions. The primary use of this system is for the testing of Charpy specimens. Full-, half-, and third-size specimens have been tested, both in the lab and remotely in a hot cell for irradiated specimens. Specimens are loaded into a transfer device which moves the specimen into a chamber, where a hot air gun is used to heat the specimen, or cold nitrogen gas is used for cooling, as required. The specimen is then quickly transferred from the furnace to the anvils and then broken. This system incorporates an instrumented tup to determine the change in voltage during the fracture process. These data are analyzed by the computer system after the test is complete. The voltage-time trace is recorded with a digital oscilloscope, transferred to the computer, and analyzed. The analysis program incorporates several unique features. It interacts with the operator and identifies the maximum voltage during the test, the amount of rapid fracture during the test (if any), and the end of the fracture process. The program then calculates the area to maximum voltage and the total area under the voltage-time curve. The data acquisition and analysis part of the system can also be used to conduct other dynamic testing. Dynamic tear and precracked specimens can be tested with an instrumented tup and analyzed in a similar manner. 3 refs., 7 figs.

  7. Evaluation of impact properties of weld joint of reactor pressure vessel steels with the use of miniaturized specimens

    Microsoft Academic Search

    Byung Jun Kim; Hideaki Mitsui; Ryuta Kasada; Akihiko Kimura

    2012-01-01

    The effects of specimen size and location of V-notch on the Charpy impact properties were investigated with different sizes of specimens, standard, CVN-1\\/2, CVN-1\\/3, and CVN-1.5 mm, for A533B steel, low Mn, high Cu, high phosphorus (P), and high Cu\\/P steel weld joint. A part of the specimens was irradiated with neutron at 563 K up to 8 × 10 n\\/cm. The heat affected

  8. How Close Is Close Enough? Testing Nonexperimental Estimates of Impact against Experimental Estimates of Impact with Education Test Scores as Outcomes. Discussion Paper.

    ERIC Educational Resources Information Center

    Wilde, Elizabeth Ty; Hollister, Robinson

    This study tested the performance of nonexperimental estimators of impacts applied to a class size reduction intervention with achievement test scores as the outcome. Nonexperimental estimates of impacts were compared to "true impact" estimates provided by a random-assignment design that assessed intervention effects. Data came from Project STAR,…

  9. How Close Is Close Enough? Testing Nonexperimental Estimates of Impact against Experimental Estimates of Impact with Education Test Scores as Outcomes. Discussion Paper No. 1242-02

    ERIC Educational Resources Information Center

    Wilde, Elizabeth Ty; Hollister, Robinson

    2002-01-01

    In this study we test the performance of some nonexperimental estimators of impacts applied to an educational intervention--reduction in class size--where achievement test scores were the outcome. We compare the nonexperimental estimates of the impacts to "true impact" estimates provided by a random-assignment design used to assess the…

  10. Shape Distribution of Fragments from Microsatellite Impact Tests

    NASA Technical Reports Server (NTRS)

    Liou, J.C.; Hanada, T.

    2009-01-01

    Fragment shape is an important factor for conducting reliable orbital debris damage assessments for critical space assets, such as the International Space Station. To date, seven microsatellite impact tests have been completed as part of an ongoing collaboration between Kyushu University and the NASA Orbital Debris Program Office. The target satellites ranged in size from 15 cm 15 cm 15 cm to 20 cm 20 cm 20 cm. Each target satellite was equipped with fully functional electronics, including circuits, battery, and transmitter. Solar panels and multi-layer insulation (MLI) were added to the target satellites of the last two tests. The impact tests were carried out with projectiles of different sizes and impact speeds. All fragments down to about 2 mm in size were collected and analyzed based on their three orthogonal dimensions, x, y, and z, where x is the longest dimension, y is the longest dimension in the plane perpendicular to x, and z is the longest dimension perpendicular to both x and y. Each fragment was also photographed and classified by shape and material composition. This data set serves as the basis of our effort to develop a fragment shape distribution. Two distinct groups can be observed in the x/y versus y/z distribution of the fragments. Objects in the first group typically have large x/y values. Many of them are needle-like objects originating from the fragmentation of carbon fiber reinforced plastic materials used to construct the satellites. Objects in the second group tend to have small x/y values, and many of them are box-like or plate-like objects, depending on their y/z values. Each group forms the corresponding peak in the x/y distribution. However, only one peak can be observed in the y/z distribution. These distributions and how they vary with size, material type, and impact parameters will be described in detail within the paper.

  11. Testing and simulation of composite laminates under impact loading

    NASA Astrophysics Data System (ADS)

    Dang, Xinglai

    Owing to their high stiffness-to-weight and high strength-to-weight ratios, fiber-reinforced polymer-matrix composite laminates are excellent materials for high-performance structures. However, their properties in the thickness direction are very poor as they are weakly bonded by polymeric matrices through laminate interfaces. Accordingly, when a composite laminate is subjected to impact loading, high interlaminar stresses along with the low interlaminar strengths could easily result in interlaminar damage such as delamination. This thesis investigated the response of composite laminates under low-velocity impact and presented numerical techniques for impact simulation. To begin with, instrumented drop-weight impacts ranging from subperforation to perforation levels were introduced to composite laminates having various dimensions and thicknesses. Damaged composite laminates were then subjected to compression-after-impact tests for evaluations of residual properties. Experimental results revealed that perforation was an important damage milestone since impact parameters such as peak force, contact duration, maximum deflection and energy absorption, and residual properties such as compressive stiffness, strength and energy absorption all reached critical levels as perforation took place. It was also found that thickness played a more important role than in-plane dimensions in perforation process. In order to understand more about the relationship between laminate thickness and perforation resistance and to present an economical method to improve perforation resistance, thick laminated composite plates and their assembled counterparts were investigated and compared. An energy profile correlating the impact energy and absorbed energy at all energy levels for each type of composite plates investigated was established and found to be able to address the relationship between energy and damage. Experimental results concluded that increasing thickness was more efficient than improving assembling stiffness in raising perforation resistance. As a first step to simulate composite response to impact loading, LS-DYNA3D was used for numerical analysis. However, due to its inability to describe interlaminar stresses, no delamination simulation could be achieved. As delamination played a very important role in damage process, a computational scheme capable of identifying interlaminar stresses and considering both numerical accuracy and computational efficiency was required for impact simulation. Accounting for interlaminar shear stress continuity and having degrees of freedom independent of layer number, a laminate theory named Generalized Zigzag Theory was formulated into a finite element subroutine and integrated into ABAQUS code. The computational scheme was able to present reasonable interlaminar shear stresses via an updated Lagragian algorithm. Combining the calculated interlaminar stresses with a delamination failure criterion, the computer program was able to predict the response of composite laminates up to the onset of delamination. Further computational simulation involving all damage modes should be considered in future studies.

  12. An assessment of testing requirement impacts on nuclear thermal propulsion ground test facility design

    SciTech Connect

    Shipers, L.R.; Ottinger, C.A.; Sanchez, L.C.

    1993-10-25

    Programs to develop solid core nuclear thermal propulsion (NTP) systems have been under way at the Department of Defense (DoD), the National Aeronautics and Space Administration (NASA), and the Department of Energy (DOE). These programs have recognized the need for a new ground test facility to support development of NTP systems. However, the different military and civilian applications have led to different ground test facility requirements. The Department of Energy (DOE) in its role as landlord and operator of the proposed research reactor test facilities has initiated an effort to explore opportunities for a common ground test facility to meet both DoD and NASA needs. The baseline design and operating limits of the proposed DoD NTP ground test facility are described. The NASA ground test facility requirements are reviewed and their potential impact on the DoD facility baseline is discussed.

  13. Impact properties of irradiated HT9 from the fuel duct of FFTF

    NASA Astrophysics Data System (ADS)

    Byun, Thak Sang; Daniel Lewis, W.; Toloczko, Mychailo B.; Maloy, Stuart A.

    2012-02-01

    This paper reports Charpy impact test data for the ACO-3 duct material (HT9) from the Fast Flux Test Facility (FFTF) and its archive material. Irradiation doses for the specimens were in the range of 3-148 dpa and irradiation temperatures in the range of 378-504 °C. The impact tests were performed for the small V-notched Charpy specimens with dimensions of 3 × 4 × 27 mm at an impact speed of 3.2 m/s in a 25 J capacity machine. Irradiation lowered the upper-shelf energy (USE) and increased the transition temperatures significantly. The shift of ductile-brittle transition temperatures (?DBTT) was greater after relatively low temperature irradiation. The USE values were in the range of 5.5-6.7 J before irradiation and decreased to the range of 2-5 J after irradiation. Lower USEs were measured for lower irradiation temperatures and specimens with T-L orientation. The dose dependences of transition temperature and USE were not significant because of the radiation effect on impact behavior nearly saturated at the lowest dose of about 3 dpa. A comparison showed that the lateral expansion of specimens showed a linear correlation with absorbed impact energy, but with large scatter in the results. Size effect was also discussed to clarify the differences in the impact property data from subsize and standard specimens as well as to provide a basis for comparison of data from different specimens. The USE and ?DBTT data from different studies were compared.

  14. Implications of the impact of prevalence on test thresholds and outcomes: lessons from tuberculosis

    E-print Network

    Bentley, Tanya GK; Catanzaro, Antonino; Ganiats, Theodore G

    2012-01-01

    in considering the impact on testing decisions of theImpact on results " True positives " True negatives Testingimpact of delayed diagnoses. This analysis also ignores other issues involved in testing

  15. Testing the impact attenuation of loose-fill playground surfaces

    PubMed Central

    Mack, M.; Sacks, J.; Thompson, D.

    2000-01-01

    Objectives—Our objective was to measure the impact attenuation performance of five types of loose-fill playground surfaces at a variety of drop heights, material depths, and conditions. Methods—In a laboratory setting, an instrumented head form was dropped on varying depths of loose-fill materials at one foot height increments until critical deceleration values were exceeded. The effects of test box size, material temperature, and compression were also studied. Results—Data suggest that a larger test box size influences test results. Uncompressed materials performed quite unexpectedly, that is, resilience did not necessarily increase with increasing depth of material and temperature did not have uniform effects. Compression before testing improved consistency of results. Conclusion—The current standard test procedure (ASTM F1292) appears problematic for loose-fill materials. Our results indicate that (1) shredded rubber was the best performer; (2) there was little difference between sand, wood fibers, and wood chips; and (3) pea gravel had the worst performance, making it a poor choice for playground surfacing. PMID:10875672

  16. Vidock: a Tool for Impact Analysis of Aspect Weaving on Test Cases

    E-print Network

    Paris-Sud XI, Université de

    Vidock: a Tool for Impact Analysis of Aspect Weaving on Test Cases Romain Delamare1 , Freddy Munoz1, through aspect weaving, has an impact on its existing behaviors. If test cases ex- ist for the program, it is necessary to identify the subset of test cases that trigger the behavior impacted by the aspect. This subset

  17. Automated Test Generation for Access Control Policies via Change-Impact Analysis

    E-print Network

    Young, R. Michael

    Automated Test Generation for Access Control Policies via Change-Impact Analysis Evan Martin North- impact analysis. Our experimental results show that Cirg can effectively generate tests to achieve high- erates tests for access control policies by leveraging change- impact analysis. We have implemented

  18. Model calibration and validation of an impact test simulation

    SciTech Connect

    Hemez, F. M. (François M.); Wilson, A. C. (Amanda C.); Havrilla, G. N. (George N.)

    2001-01-01

    This paper illustrates the methodology being developed at Los Alamos National Laboratory for the validation of numerical simulations for engineering structural dynamics. The application involves the transmission of a shock wave through an assembly that consists of a steel cylinder and a layer of elastomeric (hyper-foam) material. The assembly is mounted on an impact table to generate the shock wave. The input acceleration and three output accelerations are measured. The main objective of the experiment is to develop a finite element representation of the system capable of reproducing the test data with acceptable accuracy. Foam layers of various thicknesses and several drop heights are considered during impact testing. Each experiment is replicated several times to estimate the experimental variability. Instead of focusing on the calibration of input parameters for a single configuration, the numerical model is validated for its ability to predict the response of three different configurations (various combinations of foam thickness and drop height). Design of Experiments is implemented to perform parametric and statistical variance studies. Surrogate models are developed to replace the computationally expensive numerical simulation. Variables of the finite element model are separated into calibration variables and control variables, The models are calibrated to provide numerical simulations that correctly reproduce the statistical variation of the test configurations. The calibration step also provides inference for the parameters of a high strain-rate dependent material model of the hyper-foam. After calibration, the validity of the numerical simulation is assessed through its ability to predict the response of a fourth test setup.

  19. Dynamic Impact Analyses and Tests of Concrete Overpacks - 13638

    SciTech Connect

    Lee, Sanghoon; Cho, Sang-Soon; Kim, Ki-Young; Jeon, Je-Eon; Seo, Ki-Seog [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)] [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-07-01

    Concrete cask is an option for spent nuclear fuel interim storage which is prevailingly used in US. A concrete cask usually consists of metallic canister which confines the spent nuclear fuel and concrete overpack. When the overpack undergoes a severe missile impact which might be caused by a tornado or an aircraft crash, it should sustain acceptable level of structural integrity so that its radiation shielding capability and the retrievability of canister are maintained. Missile impact against a concrete overpack involves two damage modes, local damage and global damage. Local damage of concrete is usually evaluated by empirical formulas while the global damage is evaluated by finite element analysis. In many cases, those two damage modes are evaluated separately. In this research, a series of numerical simulations are performed using finite element analysis to evaluate the global damage of concrete overpack as well as its local damage under high speed missile impact. We consider two types of concrete overpack, one with steel in-cased concrete without reinforcement and the other with partially-confined reinforced concrete. The numerical simulation results are compared with test results and it is shown that appropriate modeling of material failure is crucial in this analysis and the results are highly dependent on the choice of failure parameters. (authors)

  20. Logic Design for On-Chip Test ClockGeneration-Implementation Details and Impact on Delay Test Quality

    E-print Network

    Paris-Sud XI, Université de

    Logic Design for On-Chip Test ClockGeneration- Implementation Details and Impact on Delay Test on- chip high-speed clock generation, implemented to avoid expensive test equipment, is described in detail. Techniques for on-chip clock generation, meant to reduce test vector count and to increase test

  1. Excerpts from Test Films: Langley Impacting Structures Facility, Lunar Module

    NASA Technical Reports Server (NTRS)

    1968-01-01

    Excerpts from Test Films: Langley Impacting Structures Facility, Lunar Module. The film includes excerpts from three studies: (1) Landing characteristics of a dynamic model of the HL-10 manned lifting entry vehicle, conducted by Sandy M. Stubbs, in which the vehicle landed on water at horizontal velocities of 240- and 250-feet per second (ft/sec). (2) Dynamic model investigation of water pressures and accelerations encountered during landings of the Apollo spacecraft conducted by Sandy M. Stubbs, in which horizontal velocity was 50 ft/sec. and pitch attitude was -12 and -28 degrees. (3) Comparative landing impact tests of a 1/6-scale model as a free body under earth gravity and a tethered full-scale lunar module on the Lunar Gravity Simulator. Landing 8 is shown, with a vertical velocity of 10 ft/sec. and a horizontal velocity of 8 ft/sec. Motion pictures were taken at 400 and 64 pps. [Entire movie available on DVD from CASI as Doc ID 20070030993. Contact help@sti.nasa.gov

  2. Controlled Impact Demonstration instrumented test dummies installed in plane

    NASA Technical Reports Server (NTRS)

    1984-01-01

    In this photograph are seen some of dummies in the passenger cabin of the B-720 aircraft. NASA Langley Research Center instrumented a large portion of the aircraft and the dummies for loads in a crashworthiness research program. In 1984 NASA Dryden Flight Research Facility and the Federal Aviation Adimistration (FAA) teamed-up in a unique flight experiment called the Controlled Impact Demonstration (CID). The test involved crashing a Boeing 720 aircraft with four JT3C-7 engines burning a mixture of standard fuel with an additive called Anti-misting Kerosene (AMK) designed to supress fire. In a typical aircraft crash, fuel spilled from ruptured fuel tanks forms a fine mist that can be ignited by a number of sources at the crash site. In 1984 the NASA Dryden Flight Research Facility (after 1994 a full-fledged Center again) and the Federal Aviation Administration (FAA) teamed-up in a unique flight experiment called the Controlled Impact Demonstration (CID), to test crash a Boeing 720 aircraft using standard fuel with an additive designed to supress fire. The additive, FM-9, a high-molecular-weight long-chain polymer, when blended with Jet-A fuel had demonstrated the capability to inhibit ignition and flame propagation of the released fuel in simulated crash tests. This anti-misting kerosene (AMK) cannot be introduced directly into a gas turbine engine due to several possible problems such as clogging of filters. The AMK must be restored to almost Jet-A before being introduced into the engine for burning. This restoration is called 'degradation' and was accomplished on the B-720 using a device called a 'degrader.' Each of the four Pratt & Whitney JT3C-7 engines had a 'degrader' built and installed by General Electric (GE) to break down and return the AMK to near Jet-A quality. In addition to the AMK research the NASA Langley Research Center was involved in a structural loads measurement experiment, which included having instrumented dummies filling the seats in the passenger compartment. Before the final flight on December 1, 1984, more than four years of effort passed trying to set-up final impact conditions considered survivable by the FAA. During those years while 14 flights with crews were flown the following major efforts were underway: NASA Dryden developed the remote piloting techniques necessary for the B-720 to fly as a drone aircraft; General Electric installed and tested four degraders (one on each engine); and the FAA refined AMK (blending, testing, and fueling a full-size aircraft). The 15 flights had 15 takeoffs, 14 landings and a larger number of approaches to about 150 feet above the prepared crash site under remote control. These flight were used to introduce AMK one step at a time into some of the fuel tanks and engines while monitoring the performance of the engines. On the final flight (No. 15) with no crew, all fuel tanks were filled with a total of 76,000 pounds of AMK and the remotely-piloted aircraft landed on Rogers Dry Lakebed in an area prepared with posts to test the effectiveness of the AMK in a controlled impact. The CID, which some wags called the Crash in the Desert, was spectacular with a large fireball enveloping and burning the B-720 aircraft. From the standpoint of AMK the test was a major set-back, but for NASA Langley, the data collected on crashworthiness was deemed successful and just as important.

  3. A dropped-weight apparatus for low-speed impact testing of composite structures

    Microsoft Academic Search

    D. R. Ambur; C. B. Prasad; W. A. Waters

    1995-01-01

    A dropped-weight test apparatus has been developed that can be used to perform low-speed impact tests on composite aircraft structures. This vertical drop-weight test apparatus is simple, compact, inexpensive and has precision impact and self-arresting design features similar to the more sophisticated, expensive test machines. The test apparatus has been used to perform low-speed impact response studies on laminated composite

  4. Evaluating the initial impact of eliminating the retirement earnings test.

    PubMed

    Song, Jae G

    Under the retirement earnings test, Social Security benefits are reduced if earnings exceed specified amounts, although the benefit reduction is partly offset by future benefit increases. By imposing a tax on the earnings of beneficiaries, the earnings test provided a disincentive for them to supplement retirement income by working. The Senior Citizens Freedom to Work Act of 2000 eliminated the earnings test for Social Security beneficiaries who have reached the full retirement age. This article presents the first study of labor force activity (earnings and employment) among individuals aged 65-69 before and immediately after this sudden rule change. Drawing on Social Security administrative data, the author examines three widely expected reactions: increased return to work, increased hours worked, and accelerated applications for old-age benefits. The analysis finds that removing the retirement earnings test: Encouraged some workers to increase their earnings. The increases in earnings are large and significant among higher earners but are not statistically significant among lower earners. Had little effect on employment. Removing the earnings test appears to have had no immediate, significant effect on the employment rate of older workers. Employment of older people may be affected in the longer run, however. Slightly increased the pace of applications for benefits. Applications rose about 2 percent in the 65-69 age group in 2000. The overall acceleration will probably be small, however, because most individuals in this age group apply for benefits before reaching the full retirement age. Although the current analysis captures the effects of retaining older workers in the labor force, these initial results may not capture all the effects of eliminating the retirement earnings test, however, for two reasons. First, the analysis covers only a single year--the year the earnings test was eliminated. Since eliminating the earnings test may have had little effect on people who had already retired, its full effect may not be apparent for several years. Second, the analysis applies only to workers aged 65-69. Eliminating the earnings test for people above the full retirement age may also encourage younger workers to delay retirement and therefore increase their labor supply. Further analysis will therefore be required to determine the longer-run impact of eliminating the retirement earnings test. PMID:15218631

  5. Comparison of Autogenous and Alloplastic Cranioplasty Materials Following Impact Testing.

    PubMed

    Wallace, Robert D; Salt, Craig; Konofaos, Petros

    2015-07-01

    Alloplastic materials are often used when significant defects exist. Benefits include no donor site morbidity, relative ease of use, limitless supply, and predictable durability. Depending on the type of alloplast, limitations include a persistent risk of extrusion and infection. Of particular interest in relation to cranioplasties is the ability of the material to provide neuroprotection. The integrity and neuroprotective properties of autologous bone flaps, polymethylmethacrylate (PMMA), and high-density porous polyethylene (PP) were evaluated following impact testing. Three groups of New Zealand white rabbits (N?=?4) underwent a cranioplasty with either a bone flap, PMMA, or PP. In the control group (N?=?4), the animals had no cranioplasty. At the end of the eighth week, an impact was delivered to the center of each cranioplasty. At necropsy each cranium and brain was evaluated grossly and histologically. There was a statistical significant difference among groups for the severity of the hemorrhage (P?=?0.022) and the grade of cranioplasty disruption (P?=?0.0045). Autologous bone was found to be the weakest of the materials tested. In this group severe injury resulted at much lower energy levels than was observed in the control, PMMA, or PP groups. Both PMMA and PP were resistant to fracture and disruption. PMMA provided the greatest neuroprotection, followed by PP. Autologous bone provided the least protection with cranioplasty disruption and severe brain injury occurring in every patient. Brain injury patterns correlated with the degree of cranioplasty disruption regardless of the cranioplasty material. Regardless of the energy of impact, lack of dislodgement generally resulted in no obvious brain injury. PMID:26114508

  6. Impact of Rheumatoid Arthritis Disease Activity Test on Clinical Practice

    PubMed Central

    Peabody, John W.; Strand, Vibeke; Shimkhada, Riti; Lee, Rachel; Chernoff, David

    2013-01-01

    Background Variability exists in the assessment of disease activity in rheumatoid arthritis (RA) patients that may affect quality of care. Objectives To measure the impact on quality of care of a Multi-Biomarker Disease Activity (MBDA) test that quantitatively assesses RA disease activity. Methods Board-certified rheumatologists without prior experience with the MBDA test (N?=?81) were randomized into an intervention or control group as part of a longitudinal randomized-control study. All physicians were asked to care for three simulated RA patients, using Clinical Performance and Value (CPV™) vignettes, in a before and after design. CPV™ vignettes have been validated to assess the quality of clinical practice and identify variation in care. The vignettes covered all domains of a regular patient visit; scores were determined as a percentage of explicit predefined criteria completed. Three vignettes, representing typical RA cases, were administered each round. In the first round, no physician received information about the MBDA test. In the second round, only physicians in the intervention group were given educational materials about the test and hypothetical test results for each of the simulated patients. The outcome measures were the overall quality of care, disease assessment and treatment. Results The overall quality scores in the intervention group improved by 3 percent (p?=?0.02) post-intervention compared with baseline, versus no change in the control group. The greatest benefit in the intervention group was to the quality of disease activity assessment and treatment decisions, which improved by 12 percent (p<0.01) compared with no significant change in the control group. The intervention was associated with more appropriate use of biologic and/or combination DMARDs in the co-morbidity case type (p<0.01). Conclusions Based on these results, use of the MBDA test improved the assessment and treatment decisions for simulated cases of RA and may prove useful for rheumatologists in clinical practice. PMID:23667587

  7. Estimation of Impact Damage in C\\/C Composites by Drop Weight Tests

    Microsoft Academic Search

    Takakazu Yoshioka; Ichiro Takahashi

    2008-01-01

    The evaluation of impact damage properties and strength of C\\/C composites is becoming important, due to its low impact strength. In this study, the impact damage is evaluated by using the impact load-deflection diagrams and absorbed energy of specimens on a drop weight impact test. The measured impact load is decomposed in approximation components and detail components by multiple-resolution analysis

  8. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 2013-10-01 false Knees and knee impact test procedure. 572.126 Section 572.126 Transportation...OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Six-year-old Child Test Dummy, Beta Version § 572.126 Knees...

  9. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 2014-10-01 false Knees and knee impact test procedure. 572.126 Section 572.126 Transportation...OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Six-year-old Child Test Dummy, Beta Version § 572.126 Knees...

  10. 49 CFR 572.136 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 false Knees and knee impact test procedure. 572.136 Section 572.136...TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Hybrid III 5th Percentile Female Test Dummy, Alpha Version § 572.136...

  11. Supporting Controlled Experimentation with Testing Techniques: An Infrastructure and its Potential Impact

    E-print Network

    Rothermel, Gregg

    Supporting Controlled Experimentation with Testing Techniques: An Infrastructure and its Potential Impact Hyunsook Do, Sebastian Elbaum, Gregg Rothermel Department of Computer Science and Engineering Where the creation, understanding, and assessment of software testing and regression testing techniques

  12. RTM370 Polyimide Braided Composites: Characterization and Impact Testing

    NASA Technical Reports Server (NTRS)

    Chuang, Kathy C.; Revilock, Duane M.; Ruggeri, Charles R.; Criss, Jim M., Jr.; Mintz, Eric A.

    2013-01-01

    RTM370 imide oligomer based on 2,3,3',4'-biphenyl dianhydride (a-BPDA), 3,4'-oxydianiline (3,4'-ODA) and terminated with the 4-phenylethynylphthalic (PEPA) endcap has been shown to exhibit a low melt viscosity (10-30 poise) at 280 C with a pot-life of 1-2 h and a high cured glass transition temperature (Tg) of 370 C. RTM370 resin has been successfully fabricated into composites reinforced with T650-35 carbon fabrics by resin transfer molding (RTM). RTM370 composites display excellent mechanical properties up to 327 C (620 F), and outstanding property retention after aging at 288degC (550 F) for 1000 h, and under hot-wet conditions. In ballistic impact testing, RTM370 triaxial braided T650-35 carbon fiber composites exhibited enhanced energy absorption at 288 C (550 F) compared to ambient temperature.

  13. IMPROVED BAR IMPACT TESTS USING A PHOTONIC DOPPLER VELOCIMETER

    SciTech Connect

    Bless, S J; Tolman, J; Levinson, S; Nguyen, J

    2009-08-24

    Bar impact tests, using the techniques described elsewhere in this symposium, were used to measure compressive and tensile strengths of borosilicate glass, soda lime glass, and a glass ceramic. The glass ceramic was 25% crystalline spinel, furnished by Corning Inc. There are two measures of compressive strength: the peak stress that can be transmitted in unconfined compression, and the 'steady state' strength. For borosilicate glass and soda lime glass, these values were similar, being about 1.8 and 1.5 GPa, respectively. The glass ceramic (25% spinel) was almost 50% stronger. Tensile failure in the glass and glass ceramic takes places via surface flaws, and thus tensile strength is an extrinsic, as opposed to intrinsic property.

  14. Improved Bar Impact Tests Using a Photonic Doppler Velocimeter

    NASA Astrophysics Data System (ADS)

    Bless, S. J.; Tolman, J.; Levinson, S.; Nguyen, J.

    2009-12-01

    Bar impact tests, using the techniques described elsewhere in this symposium, were used to measure compressive and tensile strengths of borosilicate glass, soda lime glass, and a glass ceramic. The glass ceramic was 25% crystalline spinel, furnished by Corning Inc. There are two measures of compressive strength: the peak stress that can be transmitted in unconfined compression, and the "steady state" strength. For borosilicate glass and soda lime glass, these values were similar, being about 1.8 and 1.5 GPa, respectively. The glass ceramic (25% spinel) was almost 50% stronger. Tensile failure in the glass and glass ceramic takes places via surface flaws, and thus tensile strength is an extrinsic, as opposed to intrinsic property.

  15. Empirical correlation between package-level ball impact test and board-level drop reliability

    Microsoft Academic Search

    Chang-Lin Yeh; Yi-Shao Lai; Hsiao-Chuan Chang; Tsan-Hsien Chen

    2007-01-01

    Package-level ball impact test and board-level drop test are performed and correlated using a specific chip-scale package with solder joints of different Sn–Ag–Cu solder compositions. A positive correlation is found between characteristics of the impact force profile and reliability from the drop test, which provides a supporting basis for the package-level ball impact test to serve as a substitute of

  16. Test Directions as a Critical Component of Test Design: Best Practices and the Impact of Examinee Characteristics

    ERIC Educational Resources Information Center

    Lakin, Joni M.

    2014-01-01

    The purpose of test directions is to familiarize examinees with a test so that they respond to items in the manner intended. However, changes in educational measurement as well as the U.S. student population present new challenges to test directions and increase the impact that differential familiarity could have on the validity of test score…

  17. An Investigation of Hypothesis Testing and Power Analysis in Impact Assessment,

    E-print Network

    Burgman, Mark

    An Investigation of Hypothesis Testing and Power Analysis in Impact Assessment, using Case Studies or failure. In this thesis, several BACI-style statistical tests for impact and their statistical power were of Marine Infauna. Janet M. Carey Abstract Statistical analysis is now widely used in impact assessment

  18. Control and evaluation of particle impact conditions in a sand erosion test facility

    Microsoft Academic Search

    Y. I Oka; M Nishimura; K Nagahashi; M Matsumura

    2001-01-01

    For the prediction of actual damage to plant component materials and for making the erosion mechanisms clear, it is important to control and to evaluate the particle impact conditions in a testing facility. A sand blast type erosion test rig, which can achieve the particle impact velocities up to 135ms?1 and a wide range of impact angles has been constructed.

  19. 46 CFR 54.05-20 - Impact test properties for service of 0 °F and below.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Impact test properties for service of 0 °F and below. ...MARINE ENGINEERING PRESSURE VESSELS Toughness Tests § 54.05-20 Impact test properties for service of 0 °F and below....

  20. High-Stakes Standardized Testing & Marginalized Youth: An Examination of the Impact on Those Who Fail

    ERIC Educational Resources Information Center

    Kearns, Laura-Lee

    2011-01-01

    This study examines the impact of high-stakes, large-scale, standardized literacy testing on youth who have failed the Ontario Secondary School Literacy Test. Interviews with youth indicate that the unintended impact of high-stakes testing is more problematic than policy makers and educators may realize. In contrast to literacy policy's aims to…

  1. Measurement of Satellite Impact Test Fragments for Modeling Orbital Debris

    NASA Technical Reports Server (NTRS)

    Hill, Nicole M.

    2009-01-01

    There are over 13,000 pieces of catalogued objects 10cm and larger in orbit around Earth [ODQN, January 2009, p12]. More than 6000 of these objects are fragments from explosions and collisions. As the earth-orbiting object count increases, debris-generating collisions in the future become a statistical inevitability. To aid in understanding this collision risk, the NASA Orbital Debris Program Office has developed computer models that calculate quantity and orbits of debris both currently in orbit and in future epochs. In order to create a reasonable computer model of the orbital debris environment, it is important to understand the mechanics of creation of debris as a result of a collision. The measurement of the physical characteristics of debris resulting from ground-based, hypervelocity impact testing aids in understanding the sizes and shapes of debris produced from potential impacts in orbit. To advance the accuracy of fragment shape/size determination, the NASA Orbital Debris Program Office recently implemented a computerized measurement system. The goal of this system is to improve knowledge and understanding of the relation between commonly used dimensions and overall shape. The technique developed involves scanning a single fragment with a hand-held laser device, measuring its size properties using a sophisticated software tool, and creating a three-dimensional computer model to demonstrate how the object might appear in orbit. This information is used to aid optical techniques in shape determination. This more automated and repeatable method provides higher accuracy in the size and shape determination of debris.

  2. Instrumented impact and residual tensile strength testing of eight-ply carbon eopoxy specimens

    NASA Technical Reports Server (NTRS)

    Nettles, A. T.

    1990-01-01

    Instrumented drop weight impact testing was utilized to examine a puncture-type impact on thin carbon-epoxy coupons. Four different material systems with various eight-ply lay-up configurations were tested. Specimens were placed over a 10.3-mm diameter hole and impacted with a smaller tup (4.2-mm diameter) than those used in previous studies. Force-time plots as well as data on absorbed energy and residual tensile strength were gathered and examined. It was found that a critical impact energy level existed for each material tested, at which point tensile strength began to rapidly decrease with increasing impact energy.

  3. 78 FR 69943 - Anthropomorphic Test Devices; Q3s 3-Year-Old Child Side Impact Test Dummy, Incorporation by...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-21

    ...49 CFR Part 572 Anthropomorphic Test Devices; Q3s 3-Year-Old Child Side Impact Test Dummy, Incorporation by Reference; Proposed...NHTSA-2013-0118] RIN 2127-AL04 Anthropomorphic Test Devices; Q3s 3-Year-Old Child Side...

  4. Ignition of nonmetallic materials by impact of high-pressure oxygen. II - Evaluation of repeatability of pneumatic impact test

    NASA Technical Reports Server (NTRS)

    Schmidt, Naomi; Moffett, Gary E.; Pedley, Michael D.; Linley, Larry J.

    1989-01-01

    The gaseous oxygen pneumatic impact test is used to evaluate the suitability of nonmetallic materials for use in high-pressure oxygen systems. The test was evaluated by testing the reactivity of four materials over a range of impact pressures. The evaluation also investigated the effect of valve opening time and other test variables on the frequency of reaction. The variability of the data obtained for each test material was too large for the test method to be capable of distinguishing other than gross differences in the reactivity of materials. No relation was found between this variability and changes in valve opening time and other test variables. The materials studied were found to be unacceptable for use as reference standards. Because of the high variability of the test data, it is recommended that new methods be developed for evaluating the suitability of materials for use in high-pressure oxygen systems.

  5. Orion MPCV Water Landing Test at Hydro Impact Basin - Duration: 77 seconds.

    NASA Video Gallery

    This is the third Orion Multi-Purpose Crew Vehicle (MPCV) water landing test conducted at the Hydro Impact Basin at NASA Langley Research Center. This test represented the worst-case scenario for l...

  6. Structural identification of short/middle span bridges by rapid impact testing: theory and verification

    NASA Astrophysics Data System (ADS)

    Zhang, Jian; Zhang, Q. Q.; Guo, S. L.; Xu, D. W.; Wu, Z. S.

    2015-06-01

    A structural strain flexibility identification method by processing the multiple-reference impact testing data is proposed. First, a kind of novel long-gauge fiber optic sensor is developed for structural macro-strain monitoring. Second, the multiple-reference impact testing technology is employed, during which both the impacting force and structural strain responses are measured. The impact testing technology has unique merit because it is able to extract exact structural frequency response functions (FRFs), while other test methods, for instance ambient tests, can only output the FRFs with scaled magnitudes. Most importantly, the originality of the article is that a method of identifying the structural strain flexibility characteristic from the impact test data has been proposed, which is useful for structural static strain prediction and capacity evaluation. Examples of a six meter simple supported beam and a multiple-span continuous beam bridge have successfully verified the effectiveness of the proposed method.

  7. Paleomagnetism of impact spherules from Lonar crater, India and a test for impact-generated fields

    Microsoft Academic Search

    Benjamin P. Weiss; Shelsea Pedersen; Ian Garrick-Bethell; Sarah T. Stewart; Karin L. Louzada; Adam C. Maloof; Nicholas L. Swanson-Hysell

    2010-01-01

    Planetary surfaces have been ubiquitously melted by meteoroid impacts throughout solar system history. The resulting impact melts form some of the youngest igneous samples from rocky bodies like the Moon, Mars, and asteroids. Upon cooling, these melts may record any ambient planetary magnetic fields as well as postulated transient fields generated by impact plasmas. Impact-generated fields have been proposed as

  8. A Study of the "toss Factor" in the Impact Testing of Cermets by the Izod Pendulum Test

    NASA Technical Reports Server (NTRS)

    Probst, H B; Mchenry, Howard T

    1957-01-01

    The test method presented shows that the "toss energy" contributed by the apparatus for brittle materials is negligible. The total toss energy is considered to consist of two components. (a) recovered stored elastic energy and (b) kinetic energy contributed directly by the apparatus. The results were verified by high-speed motion pictures of the test in operation. From these photographs, velocities of tossed specimens were obtained and toss energy computed. In addition, impact energies of some titanium carbide base cermets and high-temperature alloys, as measured by the low-capacity Izod pendulum test, compare well with impact energies measured by the NACA drop test.

  9. Drop-weight impact tests and finite element modeling of cast acrylic\\/aluminum plates

    Microsoft Academic Search

    Yanxiong Liu; Benjamin Liaw

    2009-01-01

    As an extension of a previous study [1], drop-weight impact tests on cast acrylic (PMMA) plates reinforced by aluminum face sheets were carried out using an instrumented drop weight impact tester. The PMMA and aluminum layers were adhered by epoxy cured at room temperature. Depending on the impact velocity and the type of top surface (acrylic or aluminum) struck by

  10. Reinforced Carbon-Carbon Subcomponent Flat Plate Impact Testing for Space Shuttle Orbiter Return to Flight

    NASA Technical Reports Server (NTRS)

    Melis, Matthew E.; Brand, Jeremy H.; Pereira, J. Michael; Revilock, Duane M.

    2007-01-01

    Following the tragedy of the Space Shuttle Columbia on February 1, 2003, a major effort commenced to develop a better understanding of debris impacts and their effect on the Space Shuttle subsystems. An initiative to develop and validate physics-based computer models to predict damage from such impacts was a fundamental component of this effort. To develop the models it was necessary to physically characterize Reinforced Carbon-Carbon (RCC) and various debris materials which could potentially shed on ascent and impact the Orbiter RCC leading edges. The validated models enabled the launch system community to use the impact analysis software LS DYNA to predict damage by potential and actual impact events on the Orbiter leading edge and nose cap thermal protection systems. Validation of the material models was done through a three-level approach: fundamental tests to obtain independent static and dynamic material model properties of materials of interest, sub-component impact tests to provide highly controlled impact test data for the correlation and validation of the models, and full-scale impact tests to establish the final level of confidence for the analysis methodology. This paper discusses the second level subcomponent test program in detail and its application to the LS DYNA model validation process. The level two testing consisted of over one hundred impact tests in the NASA Glenn Research Center Ballistic Impact Lab on 6 by 6 in. and 6 by 12 in. flat plates of RCC and evaluated three types of debris projectiles: BX 265 External Tank foam, ice, and PDL 1034 External Tank foam. These impact tests helped determine the level of damage generated in the RCC flat plates by each projectile. The information obtained from this testing validated the LS DYNA damage prediction models and provided a certain level of confidence to begin performing analysis for full-size RCC test articles for returning NASA to flight with STS 114 and beyond.

  11. Materials Characterization Center meeting on impact testing of waste forms. Summary report

    SciTech Connect

    Merz, M.D.; Atteridge, D.; Dudder, G.

    1981-10-01

    A meeting was held on March 25-26, 1981 to discuss impact test methods for waste form materials to be used in nuclear waste repositories. The purpose of the meeting was to obtain guidance for the Materials Characterization Center (MCC) in preparing the MCC-10 Impact Test Method to be approved by the Materials Review Board. The meeting focused on two essential aspects of the test method, namely the mechanical process, or impact, used to effect rapid fracture of a waste form and the analysis technique(s) used to characterize particulates generated by the impact.

  12. Low velocity instrumented impact testing of four new damage tolerant carbon/epoxy composite systems

    NASA Technical Reports Server (NTRS)

    Lance, D. G.; Nettles, A. T.

    1990-01-01

    Low velocity drop weight instrumented impact testing was utilized to examine the damage resistance of four recently developed carbon fiber/epoxy resin systems. A fifth material, T300/934, for which a large data base exists, was also tested for comparison purposes. A 16-ply quasi-isotropic lay-up configuration was used for all the specimens. Force/absorbed energy-time plots were generated for each impact test. The specimens were cross-sectionally analyzed to record the damage corresponding to each impact energy level. Maximum force of impact versus impact energy plots were constructed to compare the various systems for impact damage resistance. Results show that the four new damage tolerant fiber/resin systems far outclassed the T300/934 material. The most damage tolerant material tested was the IM7/1962 fiber/resin system.

  13. The Effectiveness of the Component Impact Test Method for the Side Impact Injury Assessment of the Door Trim

    Microsoft Academic Search

    Younghan Youn; Jeong-Seo Koo

    2008-01-01

    The complete evaluation of the side vehicle structure and the occupant protection is only possible by means of the full scale side impact crash test. But, auto part manufacturers such as door trim makers can not conduct the test especially when the vehicle is under the developing process. The main objective of this study is to obtain the design guidelines

  14. Supporting Controlled Experimentation with Testing Techniques: An Infrastructure and its Potential Impact

    E-print Network

    Do, Hyunsook

    the impact that this infrastructure has had and can be expected to have. Keywords: software testingSupporting Controlled Experimentation with Testing Techniques: An Infrastructure and its Potential Impact Hyunsook Do, Sebastian Elbaum, Gregg Rothermel Department of Computer Science and Engineering

  15. Guidelines for Multiple Testing in Impact Evaluations of Educational Interventions. Final Report

    ERIC Educational Resources Information Center

    Schochet, Peter Z.

    2008-01-01

    Studies that examine the impacts of education interventions on key student, teacher, and school outcomes typically collect data on large samples and on many outcomes. In analyzing these data, researchers typically conduct multiple hypothesis tests to address key impact evaluation questions. Tests are conducted to assess intervention effects for…

  16. Fracture toughness and absorbed energy measurements in impact tests on brittle materials

    Microsoft Academic Search

    G. P. Marshall; J. G. Williams; C. E. Turner

    1973-01-01

    Previous work on impact testing has shown that the energy\\/unit area (w) normally measured in notched impact tests is dependent on specimen geometry. A fracture mechanical analysis has now been developed to account for the observed dependence ofw on notch size. A correction factor (f) has been derived to accommodate notch effects and this allows for the calculation of the

  17. MPM VALIDATION: SPHERE-CYLINDER IMPACT TESTS: ENERGY BALANCE

    Microsoft Academic Search

    B. Banerjee

    This report discusses the energy balance results observed during the simulation of the impact of an aluminum sphere on an aluminum plate supported by a hollow aluminum cylinder. Due to the high impact velocity, there is considerable ringing of the cylinder which causes the sum of the mechanical energies to increase. An optimal set of input parameters is identified that

  18. Low Velocity Impact Testing and Nondestructive Evaluation of Transparent Materials

    Microsoft Academic Search

    R. E. Brennan; W. H. Green

    2011-01-01

    Advanced transparent materials are used in protective systems for enhancing the survivability of ground vehicles, air vehicles, and personnel in applications such as face shields, riot gear, and vehicle windows. Low velocity impact damage can limit visibility and compromise the structural integrity of a transparent system, increasing the likelihood of further damage or penetration from a high velocity impact strike.

  19. LOW VELOCITY IMPACT TESTING AND NONDESTRUCTIVE EVALUATION OF TRANSPARENT MATERIALS

    Microsoft Academic Search

    R. E. Brennan; W. H. Green

    2011-01-01

    Advanced transparent materials are used in protective systems for enhancing the survivability of ground vehicles, air vehicles, and personnel in applications such as face shields, riot gear, and vehicle windows. Low velocity impact damage can limit visibility and compromise the structural integrity of a transparent system, increasing the likelihood of further damage or penetration from a high velocity impact strike.

  20. Public health impact of genetic tests at the end of the 20th century

    Microsoft Academic Search

    Paula W. Yoon; Bin Chen; Andrew Faucett; Mindy Clyne; Marta Gwinn; Ira M. Lubin; Wylie Burke; Muin J. Khoury

    2001-01-01

    Purpose: To evaluate genetics tests available for clinical, research, and public health purposes in terms of their public health impact as measured by the number of people who could potentially be tested. Methods: Genetic tests for the 751 inherited diseases or conditions listed in the GeneTests database as of November 2000, were classified on the basis of their use for

  1. Ductile-to-brittle transition in Sn–Zn solder joints measured by impact test

    Microsoft Academic Search

    M. Date; T. Shoji; M. Fujiyoshi; K. Sato; K. N. Tu

    2004-01-01

    Sn–9Zn and Sn–8Zn–3Bi solder balls were bonded to Cu or electroless Au\\/Ni(P) pads, and the effect of aging on impact reliability was investigated. A test similar to the classic Charpy impact test was performed to measure the impact toughness of the solder joints. In the case of the solder\\/Cu joints, ?-Cu5Zn8 at the bond interface thickened remarkably with the aging

  2. Impact tests on steel–concrete–steel sandwich beams with lightweight concrete core

    Microsoft Academic Search

    J. Y. Richard Liew; K. M. A. Sohel; C. G. Koh

    2009-01-01

    This paper studies the impact performance of Steel–Concrete–Steel (SCS) sandwich beams consisting of a lightweight concrete core sandwiched between two face plates that are connected by J-hook connectors. Impact tests were carried out by dropping free weights on to sandwich beams to investigate their structural response against impact loads. Test results revealed that the proposed J-hook connectors provide an effective

  3. The impact of test suite granularity on the cost-effectiveness of regression testing

    Microsoft Academic Search

    Gregg Rothermelt; Sebastian G. Elbaum; Alexey G. Malishevsky; Praveen Kallakurit; Brian Daviat

    2002-01-01

    Regression testing is an expensive testing process used to validate software following modifications. The cost-effectiveness of regression testing techniques varies with characteristics of test suites. One such characteristic, test suite granularity, involves the way in which test inputs are grouped into test cases within a test suite. Various cost-benefits tradeoffs have been attributed to choices of test suite granularity, but

  4. The Impact of Socioeconomic Status on High Stakes Testing Reexamined

    ERIC Educational Resources Information Center

    Baker, Melissa; Johnston, Pattie

    2010-01-01

    High-stakes testing plays a critical role in education today in the United States. Every state uses a high-stakes test to comply with the No Child Left Behind (NCLB) mandate. While many believe high-stakes testing is an acceptable and accurate way to measure students' learning, one has to ask whether high stakes testing is an effective measurement…

  5. Drop-weight impact tests and finite element modeling of cast acrylic plates

    Microsoft Academic Search

    Yanxiong Liu; Benjamin Liaw

    2009-01-01

    Low-velocity impact tests on cast acrylic (PMMA) plates were conducted using an instrumented drop-weight impact machine under various temperatures. Radial cracks were induced and the impact force histories were recorded. Results indicated that there was a glass transition temperature of cast acrylic between 185 and 200°F. Ultrasonic assessments on the impacted acrylic plates were then performed using different transducers. Focused

  6. Estimation of Impact Damage in C/C Composites by Drop Weight Tests

    NASA Astrophysics Data System (ADS)

    Yoshioka, Takakazu; Takahashi, Ichiro

    The evaluation of impact damage properties and strength of C/C composites is becoming important, due to its low impact strength. In this study, the impact damage is evaluated by using the impact load-deflection diagrams and absorbed energy of specimens on a drop weight impact test. The measured impact load is decomposed in approximation components and detail components by multiple-resolution analysis based upon the wavelet transform. And then the possibility of wavelet analysis for estimating the impact damage is studied. The results are as follows: (1) The Daubechies' wavelet is useful for smoothing the impact load signals by multiple resolution analysis in wavelet transform. (2) In the low impact energy that most of the damage does not occur, the approximation component result demanded by wavelet analysis accords with the wave pattern of numerical one that is removed free vibration component.

  7. The production of calibration specimens for impact testing of subsize Charpy specimens

    SciTech Connect

    Alexander, D.J.; Corwin, W.R.; Owings, T.D.

    1994-09-01

    Calibration specimens have been manufactured for checking the performance of a pendulum impact testing machine that has been configured for testing subsize specimens, both half-size (5.0 {times} 5.0 {times} 25.4 mm) and third-size (3.33 {times} 3.33 {times} 25.4 mm). Specimens were fabricated from quenched-and-tempered 4340 steel heat treated to produce different microstructures that would result in either high or low absorbed energy levels on testing. A large group of both half- and third-size specimens were tested at {minus}40{degrees}C. The results of the tests were analyzed for average value and standard deviation, and these values were used to establish calibration limits for the Charpy impact machine when testing subsize specimens. These average values plus or minus two standard deviations were set as the acceptable limits for the average of five tests for calibration of the impact testing machine.

  8. On the modeling of the Taylor cylinder impact test for orthotropic textured materials: Calculations and experiments

    SciTech Connect

    Maudlin, P.J.; Bingert, J.F.; House, J.W.

    1997-04-01

    Taylor impact tests using specimens cut from a rolled plate of Ta were conducted. The Ta was well-characterized in terms of flow stress and crystallographic texture. A piece-wise yield surface was interrogated from this orthotropic texture, and used in EPIC-95 3D simulations of the Taylor test. Good agreement was realized between the calculations and the post-test geometries in terms of major and minor side profiles and impact-interface footprints.

  9. Separation Phenomenon Occurring during the Charpy Impact Test of API X80 Pipeline Steels

    NASA Astrophysics Data System (ADS)

    Shin, Sang Yong; Hong, Seokmin; Bae, Jin-Ho; Kim, Kisoo; Lee, Sunghak

    2009-10-01

    A separation phenomenon occurring during the Charpy impact test of API X80 pipeline steels was investigated in the present study. A detailed microstructural analysis of fractured impact specimens showed that the band structure of bainite elongated along the rolling direction worked as prior initiation sites for separations, and that the number and length of the separations increased with the increasing volume fraction of bainite. In the steels having high work hardenability, tearing-shaped separations were found because the hammer-impacted region was seriously hardened during the impact test, which led to the reduction in the impact toughness. As the test temperature decreased, the tendency toward separations increased, but separations were not found when the cleavage fracture prevailed at very low temperatures. These findings suggested that the formation of bainite and secondary phases should be minimized for preventing or minimizing separations, because separations deteriorated the low-temperature impact toughness.

  10. Impact Testing of Aluminum 2024 and Titanium 6Al-4V for Material Model Development

    NASA Technical Reports Server (NTRS)

    Pereira, J. Michael; Revilock, Duane M.; Lerch, Bradley A.; Ruggeri, Charles R.

    2013-01-01

    One of the difficulties with developing and verifying accurate impact models is that parameters such as high strain rate material properties, failure modes, static properties, and impact test measurements are often obtained from a variety of different sources using different materials, with little control over consistency among the different sources. In addition there is often a lack of quantitative measurements in impact tests to which the models can be compared. To alleviate some of these problems, a project is underway to develop a consistent set of material property, impact test data and failure analysis for a variety of aircraft materials that can be used to develop improved impact failure and deformation models. This project is jointly funded by the NASA Glenn Research Center and the FAA William J. Hughes Technical Center. Unique features of this set of data are that all material property data and impact test data are obtained using identical material, the test methods and procedures are extensively documented and all of the raw data is available. Four parallel efforts are currently underway: Measurement of material deformation and failure response over a wide range of strain rates and temperatures and failure analysis of material property specimens and impact test articles conducted by The Ohio State University; development of improved numerical modeling techniques for deformation and failure conducted by The George Washington University; impact testing of flat panels and substructures conducted by NASA Glenn Research Center. This report describes impact testing which has been done on aluminum (Al) 2024 and titanium (Ti) 6Al-4vanadium (V) sheet and plate samples of different thicknesses and with different types of projectiles, one a regular cylinder and one with a more complex geometry incorporating features representative of a jet engine fan blade. Data from this testing will be used in validating material models developed under this program. The material tests and the material models developed in this program will be published in separate reports.

  11. Failure Behavior Characterization of Mo-Modified Ti Surface by Impact Test and Finite Element Analysis

    NASA Astrophysics Data System (ADS)

    Ma, Yong; Qin, Jianfeng; Zhang, Xiangyu; Lin, Naiming; Huang, Xiaobo; Tang, Bin

    2015-05-01

    Using the impact test and finite element simulation, the failure behavior of the Mo-modified layer on pure Ti was investigated. In the impact test, four loads of 100, 300, 500, and 700 N and 104 impacts were adopted. The three-dimensional residual impact dents were examined using an optical microscope (Olympus-DSX500i), indicating that the impact resistance of the Ti surface was improved. Two failure modes cohesive and wearing were elucidated by electron backscatter diffraction and energy-dispersive spectrometer performed in a field-emission scanning electron microscope. Through finite element forward analysis performed at a typical impact load of 300 N, stress-strain distributions in the Mo-modified Ti were quantitatively determined. In addition, the failure behavior of the Mo-modified layer was determined and an ideal failure model was proposed for high-load impact, based on the experimental and finite element forward analysis results.

  12. Soft Soil Impact Testing and Simulation of Aerospace Structures

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Jackson, Karen E.; Kellas, Sotiris

    2008-01-01

    In June 2007, a 38-ft/s vertical drop test of a 5-ft-diameter, 5-ft-long composite fuselage section that was retrofitted with a novel composite honeycomb Deployable Energy Absorber (DEA) was conducted onto unpacked sand. This test was one of a series of tests to evaluate the multi-terrain capabilities of the DEA and to generate test data for model validation. During the test, the DEA crushed approximately 6-in. and left craters in the sand of depths ranging from 7.5- to 9-in. A finite element model of the fuselage section with DEA was developed for execution in LS-DYNA, a commercial nonlinear explicit transient dynamic code. Pre-test predictions were generated in which the sand was represented initially as a crushable foam material MAT_CRUSHABLE_FOAM (Mat 63). Following the drop test, a series of hemispherical penetrometer tests were conducted to assist in soil characterization. The penetrometer weighed 20-lb and was instrumented with a tri-axial accelerometer. Drop tests were performed at 16-ft/s and crater depths were measured. The penetrometer drop tests were simulated as a means for developing a more representative soil model based on a soil and foam material definition MAT_SOIL_AND FOAM (Mat 5) in LS-DYNA. The model of the fuselage with DEA was reexecuted using the updated soil model and test-analysis correlations are presented.

  13. Water impact laboratory and flight test results for the space shuttle solid rocket booster aft skirt

    NASA Technical Reports Server (NTRS)

    Kross, D. A.; Murphy, N. C.; Rawls, E. A.

    1984-01-01

    A series of water impact tests was conducted using full-scale segment representations of the Space Shuttle Solid Rocket Booster (SRB) aft skirt structure. The baseline reinforced structural design was tested as well as various alternative design concepts. A major portion of the test program consisted of evaluating foam as a load attenuation material. Applied pressures and response strains were measured for impact velocities from 40 feet per second (ft/s) to 110 ft/s. The structural configurations, test articles, test results, and flight results are described.

  14. Capabilities of the Impact Testing Facility at Marshall Space Flight Center

    NASA Technical Reports Server (NTRS)

    Finchum, Andy; Nehls, Mary; Young, Whitney; Gray, Perry; Suggs, Bart; Lowrey, Nikki M.

    2011-01-01

    The test and analysis capabilities of the Impact Testing Facility at NASA's Marshall Space Flight Center are described. Nine different gun systems accommodate a wide range of projectile and target sizes and shapes at velocities from subsonic through hypersonic, to accomplish a broad range of ballistic and hypervelocity impact tests. These gun systems include ballistic and microballistic gas and powder guns, a two-stage light gas gun, and specialty guns for weather encounter studies. The ITF "rain gun" is the only hydrometeor impact gun known to be in existence in the United States that can provide single impact performance data with known raindrop sizes. Simulation of high velocity impact is available using the Smooth Particle Hydrodynamic Code. The Impact Testing Facility provides testing, custom test configuration design and fabrication, and analytical services for NASA, the Department of Defense, academic institutions, international space agencies, and private industry in a secure facility located at Marshall Space Flight Center, on the US Army's Redstone Arsenal in Huntsville, Alabama. This facility performs tests that are subject to International Traffic in Arms Regulations (ITAR) and DoD secret classified restrictions as well as proprietary and unrestricted tests for civil space agencies, academic institutions, and commercial aerospace and defense companies and their suppliers.

  15. Elemental Water Impact Test: Phase 2 36-Inch Aluminum Tank Head

    NASA Technical Reports Server (NTRS)

    Vassilakos, Gregory J.

    2014-01-01

    Spacecraft are being designed based on LS-DYNA simulations of water landing impacts. The Elemental Water Impact Test (EWIT) series was undertaken to assess the accuracy of LS-DYNA water impact simulations. EWIT Phase 2 featured a 36-inch aluminum tank head. The tank head was outfitted with one accelerometer, twelve pressure transducers, three string potentiometers, and four strain gages. The tank head was dropped from heights of 1 foot and 2 feet. The focus of this report is the correlation of analytical models against test data. As a measure of prediction accuracy, peak responses from the baseline LS-DYNA model were compared to peak responses from the tests.

  16. Impact of DNA Testing for Early-Onset Familial Alzheimer Disease and Frontotemporal Dementia

    Microsoft Academic Search

    Ellen J. Steinbart; Corrine O. Smith; Parvoneh Poorkaj; Thomas D. Bird

    2001-01-01

    Background: DNA testing of persons at risk for heredi- tary, degenerative neurologic diseases is relatively new. Only anecdotal reports of such testing in familial Alz- heimer disease (FAD) exist, and little is know about the personal and social impact of such testing. Methods: In a descriptive, observational study, indi- viduals at 50% risk for autosomal dominant, early-onset FAD or frontotemporal

  17. The Impact of Variability of Item Parameter Estimators on Test Information Function

    ERIC Educational Resources Information Center

    Zhang, Jinming

    2012-01-01

    The impact of uncertainty about item parameters on test information functions is investigated. The information function of a test is one of the most important tools in item response theory (IRT). Inaccuracy in the estimation of test information can have substantial consequences on data analyses based on IRT. In this article, the major part (called…

  18. Evaluation of wear resistance of thin hard coatings by a new solid particle impact test

    Microsoft Academic Search

    Y Iwai; T Honda; H Yamada; T Matsubara; M Larsson; S Hogmark

    2001-01-01

    For the evaluation of tribological properties of thin hard coatings, several experimental techniques are normally used, such as scratch testing and testing against abrasive, erosive, and sliding wear, and fretting. In this paper, we propose slurry jet, a new type of solid particle impact test, in order to quickly evaluate wear properties of thin, single layered or multilayered physical vapor

  19. VALIDITY OF EFFLUENT AND AMBIENT TOXICITY TESTS FOR PREDICTING BIOLOGICAL IMPACT, BACK RIVER, BALTIMORE HARBOR, MARYLAND

    EPA Science Inventory

    The purpose for the study was to measure the toxicity of effluents discharged to an estuary using freshwater test species and compare the predictions with the receiving water biological impact. In addition, ambient tests were done in conjunction with salinity tolerance tests to c...

  20. Hypervelocity impact testing of Space Station Freedom solar cells

    Microsoft Academic Search

    Robert J. Christie; Steve R. Best; Craig A. Myhre

    1994-01-01

    Solar array coupons designed for the Space Station Freedom electrical power system were subjected to hypervelocity impacts using the HYPER facility in the Space Power Institute at Auburn University and the Meteoroid\\/Orbital Debris Simulation Facility in the Materials and Processes Laboratory at the NASA Marshall Space Flight Center. At Auburn, the solar cells and array blanket materials received several hundred

  1. Testing Assumptions: The Impact of Two Study Abroad Program Models

    ERIC Educational Resources Information Center

    Norris, Emily Mohajeri; Dwyer, Mary M.

    2005-01-01

    There are many untested, long-held assumptions within the field of study abroad concerning the impact of program elements such as study duration, language of instruction, program models, and student housing choices. One assumption embraced within the field is that direct enrollment (or full immersion) programs are more effective at achieving a…

  2. IMPACT_S: Integrated Multiprogram Platform to Analyze and Combine Tests of Selection

    PubMed Central

    Vasconcelos, Vitor; Antunes, Agostinho

    2014-01-01

    Among the major goals of research in evolutionary biology are the identification of genes targeted by natural selection and understanding how various regimes of evolution affect the fitness of an organism. In particular, adaptive evolution enables organisms to adapt to changing ecological factors such as diet, temperature, habitat, predatory pressures and prey abundance. An integrative approach is crucial for the identification of non-synonymous mutations that introduce radical changes in protein biochemistry and thus in turn influence the structure and function of proteins. Performing such analyses manually is often a time-consuming process, due to the large number of statistical files generated from multiple approaches, especially when assessing numerous taxa and/or large datasets. We present IMPACT_S, an easy-to-use Graphical User Interface (GUI) software, which rapidly and effectively integrates, filters and combines results from three widely used programs for assessing the influence of selection: Codeml (PAML package), Datamonkey and TreeSAAP. It enables the identification and tabulation of sites detected by these programs as evolving under the influence of positive, neutral and/or negative selection in protein-coding genes. IMPACT_S further facilitates the automatic mapping of these sites onto the three-dimensional structures of proteins. Other useful tools incorporated in IMPACT_S include Jmol, Archaeopteryx, Gnuplot, PhyML, a built-in Swiss-Model interface and a PDB downloader. The relevance and functionality of IMPACT_S is shown through a case study on the toxicoferan-reptilian Cysteine-rich Secretory Proteins (CRiSPs). IMPACT_S is a platform-independent software released under GPLv3 license, freely available online from http://impact-s.sourceforge.net. PMID:25329307

  3. The Impact of High Stakes Testing: The Australian Story

    ERIC Educational Resources Information Center

    Klenowski, Val; Wyatt-Smith, Claire

    2012-01-01

    High stakes testing in Australia was introduced in 2008 by way of the National Assessment Program--Literacy and Numeracy (NAPLAN). Currently, every year all students in Years 3, 5, 7 and 9 are assessed on the same days using national tests in Reading, Writing, Language Conventions (Spelling, Grammar and Punctuation) and Numeracy. In 2010 the…

  4. Reconsidering the Impact of High-Stakes Testing

    ERIC Educational Resources Information Center

    Braun, Henry

    2004-01-01

    Over the last fifteen years, many states have implemented high-stakes tests as part of an effort to strengthen accountability for schools, teachers, and students. Predictably, there has been vigorous disagreement regarding the contributions of such policies to increasing test scores and, more importantly, to improving student learning. A recent…

  5. Drop tests and impact simulation for cell phones

    Microsoft Academic Search

    Chung-Li Hwan; Meng-Ju Lin; Chih-Ching Lo; Wen-Liang Chen

    2011-01-01

    This study conducts drop tests on cell phones according to related test standards. It is shown experimentally that damage to the inner LCD modules of cell phones occurs mostly when the cell phone drops with its front or back facing up. The probability of the aforementioned damage can be effectively reduced using the Taguchi method to modify design. Using Taguchi

  6. Measurement of Low Level Explosives Reaction in Gauged Multi-Dimensional Steven Impact Tests

    SciTech Connect

    Niles, A M; Garcia, F; Greenwood, D W; Forbes, J W; Tarver, C M; Chidester, S K; Garza, R G; Swizter, L L

    2001-05-31

    The Steven Test was developed to determine relative impact sensitivity of metal encased solid high explosives and also be amenable to two-dimensional modeling. Low level reaction thresholds occur at impact velocities below those required for shock initiation. To assist in understanding this test, multi-dimensional gauge techniques utilizing carbon foil and carbon resistor gauges were used to measure pressure and event times. Carbon resistor gauges indicated late time low level reactions 200-540 {micro}s after projectile impact, creating 0.39-2.00 kb peak shocks centered in PBX 9501 explosives discs and a 0.60 kb peak shock in a LX-04 disk. Steven Test modeling results, based on ignition and growth criteria, are presented for two PBX 9501 scenarios: one with projectile impact velocity just under threshold (51 m/s) and one with projectile impact velocity just over threshold (55 m/s). Modeling results are presented and compared to experimental data.

  7. Effects of solder alloy constitutive relationships on impact force responses of package-level solder joints under ball impact test

    Microsoft Academic Search

    Chang-Lin Yeh; Yi-Shao Lai

    2006-01-01

    The ball impact test was developed as a package-level measure for the board-level drop reliability of solder joints in the\\u000a sense that it leads to fracturing of solder joints around intermetallics, similar to that from a board-level drop test. We\\u000a investigated numerically the effects of constitutive relationships of solder alloy on transient structural responses of a\\u000a single package-level solder joint

  8. Permeability Testing of Impacted Composite Laminates for Use on Reusable Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Nettles, A. T.

    2001-01-01

    Since composite laminates are beginning to be identified for use in reusable launch vehicle propulsion systems, an understanding of their permeance is needed. A foreign object impact event can cause a localized area of permeability (leakage) in a polymer matrix composite, and it is the aim of this study to assess a method of quantifying permeability-after-impact results. A simple test apparatus is presented, and variables that could affect the measured values of permeability-after-impact were assessed. Once it was determined that valid numbers were being measured, a fiber/resin system was impacted at various impact levels and the resulting permeability measured, first with a leak check solution (qualitative) then using the new apparatus (quantitative). The results showed that as the impact level increased, so did the measured leakage. As the pressure to the specimen was increased, the leak rate was seen to increase in a nonlinear fashion for almost all the specimens tested.

  9. Impact tests on woven-roving E-glass\\/polyester laminates

    Microsoft Academic Search

    L. S Sutherland; C Guedes Soares

    1999-01-01

    Experimental results of low-energy drop-weight impact tests on woven-roving E-glass\\/polyester composites are presented. The effects of specimen thickness, impactor kinetic energy, velocity of impact and laminator are investigated. Damage was observed for all impact energies. The assumption that shear deformation dominates the response gives good agreement with the results. A model assuming a circular delamination area predicts very well the

  10. Ballistic Impact Testing of Aluminum 2024 and Titanium 6Al-4V for Material Model Development

    NASA Technical Reports Server (NTRS)

    Pereira, J. Michael; Revilock, Duane M.; Ruggeri, Charles R.; Emmerling, William C.; Altobelli, Donald J.

    2012-01-01

    An experimental program is underway to develop a consistent set of material property and impact test data, and failure analysis, for a variety of materials that can be used to develop improved impact failure and deformation models. Unique features of this set of data are that all material property information and impact test results are obtained using identical materials, the test methods and procedures are extensively documented and all of the raw data is available. This report describes ballistic impact testing which has been conducted on aluminum (Al) 2024 and titanium (Ti) 6Al-4vanadium (V) sheet and plate samples of different thicknesses and with different types of projectiles, one a regular cylinder and one with a more complex geometry incorporating features representative of a jet engine fan blade.

  11. The behavior of notched bend specimens in impact testing

    Microsoft Academic Search

    W. Böhme; J. F. Kalthoff

    1982-01-01

    Specimens made from the epoxy resin Araldite B were impacted by a drop-weight of 4.9 kg mass at a velocity of 1 m\\/s. The specimens were 412 to 550 mm long, 75 to 150 mm wide and I0 mm thick. A fixed support span of 400 mm was used throughout the investigations. The length of the initial notches was 30

  12. Technical Methods Report: Guidelines for Multiple Testing in Impact Evaluations. NCEE 2008-4018

    ERIC Educational Resources Information Center

    Schochet, Peter Z.

    2008-01-01

    This report presents guidelines for addressing the multiple comparisons problem in impact evaluations in the education area. The problem occurs due to the large number of hypothesis tests that are typically conducted across outcomes and subgroups in these studies, which can lead to spurious statistically significant impact findings. The…

  13. The mechanisms of elbow fractures: an investigation using impact tests in vitro

    Microsoft Academic Search

    A. A. Amis; J. H. Miller

    1995-01-01

    Various mechanisms of injury have been hypothesized for each of the common elbow fractures, but few have been proved. This paper describes cadaveric experiments demonstrating some fracture mechanisms. Tests were performed at different angles of flexion, with impacts around the elbow or along the forearm bones. A range of fractures occurred. Radial head and coronoid fractures followed impact along the

  14. SINGLE PARTICLE IMPACT BREAKAGE CHARACTERIZATION OF MATERIALS BY DROP WEIGHT TESTING

    Microsoft Academic Search

    Ömürden GENÇ; Levent ERGÜN; Hakan BENZER

    2004-01-01

    A drop weight tester was designed for the purpose of analyzing single particle impact breakage characteristics of different materials. Test results were evaluated through the breakage distributions of different size fractions at various impact energy levels. Breakage parameter t10 (Narayanan, 1986) is used to represent the degree of size reduction which is assumed to be represantative of the breakage product

  15. A tensile testing technique for fibre-reinforced composites at impact rates of strain

    Microsoft Academic Search

    J. Harding; L. M. Welsh

    1983-01-01

    A brief review is given of techniques which have been employed in attempts to determine the mechanical properties of composite materials under tensile impact loading. The difficulties encountered in the design of a satisfactory tensile impact testing machine for composite materials are discussed and a new method, using a modified version of the standard tensile split Hopkinson's pressure bar (SHPB),

  16. Normalization of Impact Energy by Laminate Thickness for Compression After Impact Testing

    NASA Technical Reports Server (NTRS)

    Nettles, A. T.; Hromisin, S. M.

    2013-01-01

    The amount of impact energy used to damage a composite laminate is a critical parameter when assessing residual strength properties. The compression after impact (CAI) strength of impacted laminates is dependent upon how thick the laminate is and this has traditionally been accounted for by normalizing (dividing) the impact energy by the laminate's thickness. However, when comparing CAI strength values for a given lay-up sequence and fiber/resin system, dividing the impact energy by the specimen thickness has been noted by the author to give higher CAI strength values for thicker laminates. A study was thus undertaken to assess the comparability of CAI strength data by normalizing the impact energy by the specimen thickness raised to a power to account for the higher strength of thicker laminates. One set of data from the literature and two generated in this study were analyzed by dividing the impact energy by the specimen thickness to the 1, 1.5, 2, and 2.5 powers. Results show that as laminate thickness and damage severity decreased, the value which the laminate thickness needs to be raised to in order to yield more comparable CAI data increases.

  17. Soil stiffness beneath a rigid mass using non-destructive impact testing 

    E-print Network

    Maxwell, James Christopher

    1992-01-01

    SOIL STIFFNESS BENEATH A RIGID MASS USING NON-DESTRUCTIVE IMPACT TESTING A Thesis by JAMES CHRISTOPHER MAXWELL Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE May 1992 Major Subject: Civil Engineering SOIL STIFFNESS BENEATH A RIGID MASS USING NON-DESTRUCTIVE IMPACT TESTING A Thesis by JAMES CHRISTOPHER MAXWELL Approved as to style and content by: / Jean-Louis Braud (Chair...

  18. DESIGN AND SET-UP OF A BI-PENDULUM IMPACT TESTING MACHINE

    Microsoft Academic Search

    Leonardo D'Acquisto; Roberto Montanini

    In this work the design and set-up of a bi-pendulum testing rig able to perform low-velocity impact measurements on small and medium-size components is reported. Experimental tests were conducted both to check the theoretically calculated value of the equivalent impacting mass and to quantify the overall energy losses during the idle movement of the mass. In order to provide useful

  19. Particle Impact Ignition Test Data on a Stainless Steel Hand Valve

    NASA Technical Reports Server (NTRS)

    Peralta, Stephen

    2010-01-01

    This slide presentation reviews the particle impact ignition test of a stainless steel hand valve. The impact of particles is a real fire hazard with stainless steel hand valves, however 100 mg of particulate can be tolerated. Since it is unlikely that 100 mg of stainless steel contaminant particles can be simultaneously released into this type of valve in the WSTF configuration, this is acceptable and within statistical confidence as demonstrated by testing.

  20. The evolution and impact of testing baghouse filter performance.

    PubMed

    Pham, Minh; Clark, Christina; Mckenna, John

    2012-08-01

    In 1995, the US. Environmental Protection Agency (EPA) initiated the Environmental Technology Verification (ETV) program for the purpose of generating both independent and credible performance verification of innovative technologies and helping to accelerate acceptance of these products into the marketplace to further benefit the environment and protect public health. The EPA has approved a testing protocol under this program to verify the performance of commercially available filtration products for pulse-jet baghouses in removingfine particulate matter (aerodynamic diameter<2.5 microm; PM2.5). This verification testing protocol was later used as a basis for the development of the American Society for Testing and Materials (ASTM) Method D6830-02 and the International Organization for Standardization (ISO) Method 11057. The South Coast Air Quality Management District (SCAQMD) in California and the EPA s Office of Air Quality Planning and Standards (OAQPS) highly encourage the use of ETV/ASTM-verified filtration media. This paper highlights the evolution of the standard test methods, the EPA's and SCAQMD's regulatory activities, the benefits of using verified filtration media, and the importance of including the filter performance testing in future consideration of baghouse permitting, baghouse operation and maintenance (O&M) plans, quality assurance/quality control (QA/QC), and bag monitoring plans. PMID:22916439

  1. The psychological impact of predictive genetic testing for Huntington's disease: a systematic review of the literature.

    PubMed

    Crozier, S; Robertson, N; Dale, M

    2015-02-01

    Huntington's disease (HD) is a neurodegenerative genetic condition for which a predictive genetic test by mutation analysis has been available since 1993. However, whilst revealing the future presence of the disease, testing may have an adverse psychological impact given that the disease is progressive, incurable and ultimately fatal. This review seeks to systematically explore the psychological impact of genetic testing for individuals undergoing pre-symptomatic mutation analysis. Three databases (Medline, PsycInfo and Scopus) were interrogated for studies utilising standardised measures to assess psychological impact following predictive genetic testing for HD. From 100 papers initially identified, eight articles were eligible for inclusion. Psychological impact of predictive genetic testing was not found to be associated with test result. No detrimental effect of predictive genetic testing on non-carriers was found, although the process was not found to be psychologically neutral. Fluctuation in levels of distress was found over time for carriers and non-carriers alike. Methodological weaknesses of published literature were identified, notably the needs of individuals not requesting genetic testing, as well as inadequate support for individuals registering elevated distress and declining post-test follow-up. Further assessment of these vulnerable individuals is warranted to establish the extent and type of future psychological support. PMID:25236481

  2. Hybrid composite laminates reinforced with Kevlar/carbon/glass woven fabrics for ballistic impact testing.

    PubMed

    Randjbaran, Elias; Zahari, Rizal; Jalil, Nawal Aswan Abdul; Majid, Dayang Laila Abang Abdul

    2014-01-01

    Current study reported a facile method to investigate the effects of stacking sequence layers of hybrid composite materials on ballistic energy absorption by running the ballistic test at the high velocity ballistic impact conditions. The velocity and absorbed energy were accordingly calculated as well. The specimens were fabricated from Kevlar, carbon, and glass woven fabrics and resin and were experimentally investigated under impact conditions. All the specimens possessed equal mass, shape, and density; nevertheless, the layers were ordered in different stacking sequence. After running the ballistic test at the same conditions, the final velocities of the cylindrical AISI 4340 Steel pellet showed how much energy was absorbed by the samples. The energy absorption of each sample through the ballistic impact was calculated; accordingly, the proper ballistic impact resistance materials could be found by conducting the test. This paper can be further studied in order to characterise the material properties for the different layers. PMID:24955400

  3. Hybrid Composite Laminates Reinforced with Kevlar/Carbon/Glass Woven Fabrics for Ballistic Impact Testing

    PubMed Central

    Randjbaran, Elias; Zahari, Rizal; Abdul Jalil, Nawal Aswan; Abang Abdul Majid, Dayang Laila

    2014-01-01

    Current study reported a facile method to investigate the effects of stacking sequence layers of hybrid composite materials on ballistic energy absorption by running the ballistic test at the high velocity ballistic impact conditions. The velocity and absorbed energy were accordingly calculated as well. The specimens were fabricated from Kevlar, carbon, and glass woven fabrics and resin and were experimentally investigated under impact conditions. All the specimens possessed equal mass, shape, and density; nevertheless, the layers were ordered in different stacking sequence. After running the ballistic test at the same conditions, the final velocities of the cylindrical AISI 4340 Steel pellet showed how much energy was absorbed by the samples. The energy absorption of each sample through the ballistic impact was calculated; accordingly, the proper ballistic impact resistance materials could be found by conducting the test. This paper can be further studied in order to characterise the material properties for the different layers. PMID:24955400

  4. Polynomial cointegration tests of anthropogenic impact on global warming

    NASA Astrophysics Data System (ADS)

    Beenstock, M.; Reingewertz, Y.; Paldor, N.

    2012-11-01

    We use statistical methods for nonstationary time series to test the anthropogenic interpretation of global warming (AGW), according to which an increase in atmospheric greenhouse gas concentrations raised global temperature in the 20th century. Specifically, the methodology of polynomial cointegration is used to test AGW since during the observation period (1880-2007) global temperature and solar irradiance are stationary in 1st differences, whereas greenhouse gas and aerosol forcings are stationary in 2nd differences. We show that although these anthropogenic forcings share a common stochastic trend, this trend is empirically independent of the stochastic trend in temperature and solar irradiance. Therefore, greenhouse gas forcing, aerosols, solar irradiance and global temperature are not polynomially cointegrated, and the perceived relationship between these variables is a spurious regression phenomenon. On the other hand, we find that greenhouse gas forcings might have had a temporary effect on global temperature.

  5. Polynomial cointegration tests of anthropogenic impact on global warming

    NASA Astrophysics Data System (ADS)

    Beenstock, M.; Reingewertz, Y.; Paldor, N.

    2012-07-01

    We use statistical methods for nonstationary time series to test the anthropogenic interpretation of global warming (AGW), according to which an increase in atmospheric greenhouse gas concentrations raised global temperature in the 20th century. Specifically, the methodology of polynomial cointegration is used to test AGW since during the observation period (1880-2007) global temperature and solar irradiance are stationary in 1st differences whereas greenhouse gases and aerosol forcings are stationary in 2nd differences. We show that although these anthropogenic forcings share a common stochastic trend, this trend is empirically independent of the stochastic trend in temperature and solar irradiance. Therefore, greenhouse gas forcing, aerosols, solar irradiance and global temperature are not polynomially cointegrated. This implies that recent global warming is not statistically significantly related to anthropogenic forcing. On the other hand, we find that greenhouse gas forcing might have had a temporary effect on global temperature.

  6. The Impact of Intensive Reading Interventions on Student Standardized Test Scores

    ERIC Educational Resources Information Center

    Munoz, Carolyn Sue

    2010-01-01

    The purpose of this study was to identify the impact intensive reading instruction had for 28 students with learning disabilities at the middle school level on standardized tests. National Assessment of Education Progress testing indicates that across the United States, learning disabled students literacy skills are decreasing annually, and these…

  7. Examining the Impact of Audio Presentation on Tests of Reading Comprehension

    ERIC Educational Resources Information Center

    Laitusis, Cara Cahalan

    2010-01-01

    This study examined the impact of a read-aloud accommodation on standardized test scores of reading comprehension at grades 4 and 8. Under a repeated measures design, students with and without reading-based learning disabilities took both a standard administration and a read-aloud administration of a reading comprehension test. Results show that…

  8. The analysis of instrumented impact tests using a mass-spring model

    Microsoft Academic Search

    J. G. Williams; G. C. Adams

    1987-01-01

    The Charpy impact test is modelled as a mass on a spring which is loaded via a contact stiffness. The strain energy release rate G is evaluated for this model for the case of slow crack growth rate initiation. The solution involves the kinetic energy and is shown to be harmonic in nature. Correction factors are then deduced for tests

  9. Issues in Multi-reference Impact Testing of Steel-stringer Bridges

    Microsoft Academic Search

    M. Lenett; N. Catbas; V. Hunt; A. E. Aktan; A. Helmicki; D. L. Brown

    1997-01-01

    A recommended methodology is presented for the condition assessment and structural evaluation of a highway bridge. Based upon the structural identification concept, this global NDE method employs the modal test technique of multiple reference impact testing as its principle experimental tool. Modal flexibility provides a conceptual, quantitative, comprehensive and damage- sensitive signature for the structure. A research project is underway

  10. A Study on the Measurement Instrumentation for a Custom-Made Bipendulum Impact Testing Machine

    Microsoft Academic Search

    Leonardo D'Acquisto; Roberto Montanini

    2008-01-01

    Experimental investigations of structures under impact loads are normally carried out by means of drop-weight testing rigs, which are often tailor made, and require sensors for fast transient measurement of mechanical quantities (namely, force, displacement, velocity, and absorbed energy). Since these tests are quite expensive, time consuming, and, often, not repeatable, the sensors must provide reliable and interpretable results in

  11. An Approach for Addressing the Multiple Testing Problem in Social Policy Impact Evaluations

    ERIC Educational Resources Information Center

    Schochet, Peter Z.

    2009-01-01

    In social policy evaluations, the multiple testing problem occurs due to the many hypothesis tests that are typically conducted across multiple outcomes and subgroups, which can lead to spurious impact findings. This article discusses a framework for addressing this problem that balances Types I and II errors. The framework involves specifying…

  12. Space Shuttle solid rocket booster initial water impact loads and dynamics - Analysis, tests, and flight experience

    Microsoft Academic Search

    D. A. Kross; L. A. Kiefling; N. C. Murphy; E. A. Rawls

    1983-01-01

    A series of scale model tests, finite element dynamic response analyses and full scale segment tests have been performed for purposes of developing design criteria for the initial water impact loading conditions applied to the internal stiffener rings located in the aft skirt portion of the Space Shuttle Solid Rocket Booster (SRB). In addition, flight experience has yielded information relative

  13. Accountability, incentives and behavior: the impact of high-stakes testing in the Chicago Public Schools

    Microsoft Academic Search

    Brian A. Jacob

    2005-01-01

    The recent federal education bill, No Child Left Behind, requires states to test students in grades 3 to 8 each year and to judge school performance on the basis of these test scores. While intended to maximize student learning, there is little empirical evidence about the effectiveness of such policies. This study examines the impact of an accountability policy implemented

  14. The Impact of High-Stakes Testing on Curriculum and Pedagogy: A Teacher Perspective from Australia

    ERIC Educational Resources Information Center

    Polesel, John; Rice, Suzanne; Dulfer, Nicole

    2014-01-01

    Debates continue about how high-stakes testing regimes influence schools at all levels: their impact on teaching practices, distribution of resources and curriculum provision, and whether they achieve the intended increases in student achievement in targeted areas. In 2008, the Australian government Introduced a national testing scheme, the"…

  15. The Risk of Adverse Impact in Selections Based on a Test with Known Effect Size

    ERIC Educational Resources Information Center

    De Corte, Wilfried; Lievens, Filip

    2005-01-01

    The authors derive the exact sampling distribution function of the adverse impact (AI) ratio for single-stage, top-down selections using tests with known effect sizes. Subsequently, it is shown how this distribution function can be used to determine the risk that a future selection decision on the basis of such tests will result in an outcome that…

  16. Compression-impact testing of aluminum at elevated temperatures

    Microsoft Academic Search

    J. L. Chiddister; L. E. Malvern

    1963-01-01

    This paper presents and experimental technique for determining compressive stress-strain curves well into the plastic range of relatively soft metals at strain rates from 300 to 2000 sec–1 at six temperatures from 30 to 550° C. More than 100 curves were obtained on annealed 1100° F aluminum. The strain-rate dependence in these tests could be fitted quite well either by

  17. Design of Spacecraft Missions to Test Kinetic Impact for Asteroid Deflection

    NASA Technical Reports Server (NTRS)

    Barbee, Brent W.; Hernandez, Sonia

    2012-01-01

    Earth has previously been struck with devastating force by near-Earth asteroids (NEAs) and will be struck again. Telescopic search programs aim to provide advance warning of such an impact, but no techniques or systems have yet been tested for deflecting an incoming NEA. To begin addressing this problem, we have analyzed the more than 8000 currently known NEAs to identify those that offer opportunities for safe and meaningful near-term tests of the proposed kinetic impact asteroid deflection technique. In this paper we present our methodology and results, including complete mission designs for the best kinetic impactor test mission opportunities.

  18. Measurement of Low Level Explosives Reaction in Gauged Multi-Dimensional Steven Impact Tests

    NASA Astrophysics Data System (ADS)

    Niles, A. M.; Forbes, J. W.; Tarver, C. M.; Chidester, S. K.; Garcia, F.; Greenwood, D. W.; Garza, R. G.

    2001-06-01

    The Steven Test was developed to determine relative impact sensitivity of metal encased solid high explosives and be amenable to two-dimensional modeling. Low level reaction thresholds occur at impact velocities below those required for shock initiation. To assist in understanding this test, multi-dimensional gauge techniques utilizing carbon foil and carbon resistor gauges were used to measure pressure and event times. Carbon resistor gauges indicated late time low level reactions 350 ms after projectile impact, creating 0.5-0.6 kb peak shocks centered in PBX 9501 explosives discs. Steven Test calculations based on ignition and growth criteria predict low level reactions occurring at 335 ms which agrees well with experimental data. Additional gauged experiments simulating the Steven Test have been performed and will be discussed. * This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National laboratory under contract No. W-7405-Eng-48.

  19. Paleomagnetism of impact spherules from Lonar crater, India and a test for impact-generated fields

    E-print Network

    Stewart, Sarah T.

    , and Planetary Sciences, Massachusetts Institute of Technology 54-814, 77 Massachusetts Ave., Cambridge, MA 02139-generated fields Moon Mars asteroids Planetary surfaces have been ubiquitously melted by meteoroid impacts rocky bodies like the Moon, Mars, and asteroids. Upon cooling, these melts may record any ambient

  20. Impact testing of the H1224A shipping/storage container

    SciTech Connect

    Harding, D.C.; Bobbe, J.G.; Stenberg, D.R.; Arviso, M.

    1994-05-01

    H1224A weapons containers have been used for years by the Department of Energy and Department of Defense to transport and store W78 warhead midsections. Although designed to protect these midsections only in low-energy handling drop and impact accidents, a recent transportation risk assessment effort has identified a need to evaluate the container`s ability to protect weapons in higher-energy environments. Four impact tests were performed on H1224A containers with W78 Mod 6c mass mockup midsections inside, onto an essentially unyielding target. Dynamic acceleration and strain levels were recorded during the side-on and end-on impacts, each at 12.2 m/s (40 ft/s) and 38.1 m/s (125 ft/s). Measured peak accelerations experienced by the midsections during lower velocity impacts ranged from 250 to 600 Gs for the end-on impact and 350 to 600 Gs for the side-on impact. Measured peak accelerations of the midsections during the higher velocity impacts ranged from 3,000 to 10,000 Gs for the end-on impact and 8,000 to 10,000 Gs for the side-on impact. Deformations in the H1224A container ranged from minimal to severe buckling and weld tearing. At higher impact velocities, the H1224A container may not provide significant energy absorption for the re-entry vehicle midsection but can provide some confinement of potentially damaged components.

  1. Long-Term Test-Retest Reliability of Baseline Cognitive Assessments Using ImPACT

    Microsoft Academic Search

    Philip Schatz

    2010-01-01

    Background: Computer-based assessment programs are commonly used to document baseline cognitive performance for comparison with postconcussion testing. There are currently no guidelines for how often baseline assessments should be updated, and no data documenting the test-retest stability of baseline measures over relevant time periods.Purpose: To establish long-term test-retest reliability of baseline assessments using ImPACT, and to compare various statistical methods

  2. Evaluation of PVD nitride coatings, using impact, scratch and Rockwell-C adhesion tests

    Microsoft Academic Search

    W. Heinke; A. Leyland; A. Matthews; G. Berg; C. Friedrich; E. Broszeit

    1995-01-01

    In this work the scratch test, the impact test and the Rockwell-C adhesion test were compared by investigating the adhesion properties of three types of sputtered physical vapour deposition coatings: TiN, CrN and Cr2N. Each coating type was deposited on polished SAE 52100 steel, with different thicknesses in the nominal range of 2–20 ?m, to evaluate the thickness influence on

  3. The split Hopkinson bar, a versatile tool for the impact testing of concrete

    Microsoft Academic Search

    H. W. Reinhardt; H. A. Körmeling; A. J. Zielinski

    1986-01-01

    Material properties under impact loading were studied by means of the split Hopkinson bar method. The paper describes the\\u000a basic features of the equipment and gives the technical specifications of the matrials and components used. The equipment,\\u000a which had been designed for uniaxial tensile loading, was adapted for pull-out bond testing, for cryogenic testing, and for\\u000a biaxial compresion\\/tension testing. The

  4. The impact of PSA testing frequency on prostate cancer incidence and treatment in older men

    Microsoft Academic Search

    Y-H Shao; P C Albertsen; W Shih; C B Roberts; G L Lu-Yao

    2011-01-01

    To quantify the downstream impact of PSA testing on cancer characteristics and utilization of cancer therapies among men aged 70 or older, we utilized patients diagnosed with prostate cancer in 2004–2005 in the Surveillance, Epidemiology and End Results (SEER)-Medicare and their Medicare claims before their cancer diagnosis during 2000–2005. Among men in the highest testing group (4–6 PSA tests), 75%

  5. Determine ISS Soyuz Orbital Module Ballistic Limits for Steel Projectiles Hypervelocity Impact Testing

    NASA Technical Reports Server (NTRS)

    Lyons, Frankel

    2013-01-01

    A new orbital debris environment model (ORDEM 3.0) defines the density distribution of the debris environment in terms of the fraction of debris that are low-density (plastic), medium-density (aluminum) or high-density (steel) particles. This hypervelocity impact (HVI) program focused on assessing ballistic limits (BLs) for steel projectiles impacting the enhanced Soyuz Orbital Module (OM) micrometeoroid and orbital debris (MMOD) shield configuration. The ballistic limit was defined as the projectile size on the threshold of failure of the OM pressure shell as a function of impact speeds and angle. The enhanced OM shield configuration was first introduced with Soyuz 30S (launched in May 2012) to improve the MMOD protection of Soyuz vehicles docked to the International Space Station (ISS). This test program provides HVI data on U.S. materials similar in composition and density to the Russian materials for the enhanced Soyuz OM shield configuration of the vehicle. Data from this test program was used to update ballistic limit equations used in Soyuz OM penetration risk assessments. The objective of this hypervelocity impact test program was to determine the ballistic limit particle size for 440C stainless steel spherical projectiles on the Soyuz OM shielding at several impact conditions (velocity and angle combinations). This test report was prepared by NASA-JSC/ HVIT, upon completion of tests.

  6. Impact of Acoustic Standing Waves on Structural Responses: Reverberant Acoustic Testing (RAT) vs. Direct Field Acoustic Testing (DFAT)

    NASA Technical Reports Server (NTRS)

    Kolaini, Ali R.; Doty, Benjamin; Chang, Zensheu

    2012-01-01

    Loudspeakers have been used for acoustic qualification of spacecraft, reflectors, solar panels, and other acoustically responsive structures for more than a decade. Limited measurements from some of the recent speaker tests used to qualify flight hardware have indicated significant spatial variation of the acoustic field within the test volume. Also structural responses have been reported to differ when similar tests were performed using reverberant chambers. To address the impact of non-uniform acoustic field on structural responses, a series of acoustic tests were performed using a flat panel and a 3-ft cylinder exposed to the field controlled by speakers and repeated in a reverberant chamber. The speaker testing was performed using multi-input-single-output (MISO) and multi-input-multi-output (MIMO) control schemes with and without the test articles. In this paper the spatial variation of the acoustic field due to acoustic standing waves and their impacts on the structural responses in RAT and DFAT (both using MISO and MIMO controls for DFAT) are discussed in some detail.

  7. A Change Impact Model Encompassing Ripple Effect and Regression Testing Hind Kabaili, Rudolf K. Keller and Franois Lustman

    E-print Network

    Keller, Rudolf K.

    A Change Impact Model Encompassing Ripple Effect and Regression Testing Hind Kabaili, Rudolf K testing. In the remainder of this paper, we first give an overview of the change impact model to accommodate changes, we have defined a change impact model for object-oriented systems. As previously defined

  8. Supplemental final environmental impact statement for advanced solid rocket motor testing at Stennis Space Center

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Since the Final Environmental Impact Statement (FEIS) and Record of Decision on the FEIS describing the potential impacts to human health and the environment associated with the program, three factors have caused NASA to initiate additional studies regarding these issues. These factors are: (1) The U.S. Army Corps of Engineers and the Environmental Protection Agency (EPA) agreed to use the same comprehensive procedures to identify and delineate wetlands; (2) EPA has given NASA further guidance on how best to simulate the exhaust plume from the Advanced Solid Rocket Motor (ASRM) testing through computer modeling, enabling more realistic analysis of emission impacts; and (3) public concerns have been raised concerning short and long term impacts on human health and the environment from ASRM testing.

  9. Measurement of Low Level Explosives Reaction in the Two-Dimensional Steven Impact Test

    NASA Astrophysics Data System (ADS)

    Forbes, J. W.; Garcia, F.; Greenwood, D. W.; Garza, R. G.; Tarver, C. M.; Chidester, S. K.

    1999-06-01

    The two-dimensional Steven impact test has been developed to be reproducible and amenable to computer modeling. Experiments were performed where explosives were impacted at levels below shock initiation levels. Carbon foil and carbon resistor pressure gauges were used. The carbon resistor gauges indicate a late time low level reaction at 300-400 ?s after impact for inputs of 2-6 kb peak shocks at the center of explosive discs. Some experiments simulating the Steven impact test were done on a gas gun with carbon foil gauges in PMMA. Hydrodynamic calculations will be used to evaluate the gauge performance in these experiments. The long term goal is to develop two-dimensional shock diagnostic techniques that are more than just time of arrival indicators.

  10. Drop-Weight Impact Tests with the Use of Laser-Doppler Velocimetry

    Microsoft Academic Search

    J. M. Hodgkinson; N. S. Vlachos; J. H. Whitelaw; J. G. Williams

    1982-01-01

    The application of laser-Doppler velocimetry to the measurement of projectile velocity during falling-weight, three-point bend impact tests on PMMA has allowed the determination of parameters hitherto inaccessible by conventional energy-measuring methods. At projectile velocities of 2 m\\/s and typical impact loading times of less than 1 ms, more than 50 velocity readings were possible. The ability of the method to

  11. FTIR study of hydrogen bonds in coal under drop weight impact testing.

    PubMed

    Li, Cheng-Wu; Wang, Jin-Gui; Xie, Bei-Jing; Dong, Li-Hui; Sun, Ying-Feng; Cao, Xu

    2014-11-01

    There are many hydrogen bonds in coal, which affect the chemical structure and properties of coal. FTIR has been applied to the characterization study of the hydrogen bonds of Dongpang coals, which were under drop weight impact. There exists five kinds of hydrogen bonds in the coal: free OH groups, OH...?, OH...OH, cyclic OH tetramers and OH...N. Absorption strength of intermolecular hydrogen bonds markedly declined after impact. Free OH groups mechanical-power chemical reacted in drop weight impact testing. The infrared spectrum were curve-resolved into their component bands. The absorption strength of various hydrogen bonds decreased with the increase of impact energy, but the trend was slowing. By statistical relationship between then, we find then complying with power function relationship. By comparing the exponents of fitted equations, we concluded that failure sensitivity sequence of hydrogen bonds to the impact: free OH groups > cyclic OH tetramers > OH...N > OH...? > OH...OH. PMID:25752039

  12. The impact of equilibrium assumptions on tests of selection.

    PubMed

    Crisci, Jessica L; Poh, Yu-Ping; Mahajan, Shivani; Jensen, Jeffrey D

    2013-01-01

    With the increasing availability and quality of whole genome population data, various methodologies of population genetic inference are being utilized in order to identify and quantify recent population-level selective events. Though there has been a great proliferation of such methodology, the type-I and type-II error rates of many proposed statistics have not been well-described. Moreover, the performance of these statistics is often not evaluated for different biologically relevant scenarios (e.g., population size change, population structure), nor for the effect of differing data sizes (i.e., genomic vs. sub-genomic). The absence of the above information makes it difficult to evaluate newly available statistics relative to one another, and thus, difficult to choose the proper toolset for a given empirical analysis. Thus, we here describe and compare the performance of four widely used tests of selection: SweepFinder, SweeD, OmegaPlus, and iHS. In order to consider the above questions, we utilize simulated data spanning a variety of selection coefficients and beneficial mutation rates. We demonstrate that the LD-based OmegaPlus performs best in terms of power to reject the neutral model under both equilibrium and non-equilibrium conditions-an important result regarding the relative effectiveness of linkage disequilibrium relative to site frequency spectrum based statics. The results presented here ought to serve as a useful guide for future empirical studies, and provides a guide for statistical choice depending on the history of the population under consideration. Moreover, the parameter space investigated and the Type-I and Type-II error rates calculated, represent a natural benchmark by which future statistics may be assessed. PMID:24273554

  13. Safety assessment characteristics of pedestrian legform impactors in vehicle-front impact tests.

    PubMed

    Matsui, Yasuhiro

    2014-12-01

    This study investigated the characteristics of safety assessment results of front-area vehicle impact tests carried out using the Transport Research Laboratory (TRL) legform impactor and a flexible legform impactor (FLEX legform impactor). Different types of vehicles (sedan, sport utility vehicle, high-roof K-car, and light cargo van) were examined. The impact locations in the study were the center of the bumper and an extremely stiff structure of the bumper (i.e., in front of the side member) of each tested vehicle. The measured injury criteria were normalized by injury assessment reference values of each legform impactor. The test results for center and side-member impacts indicated that there were no significant differences in ligament injury assessments derived from the normalized knee ligament injury measures between the TRL legform impactor and the FLEX legform impactor. Evaluations made using the TRL legform impactor and the FLEX legform impactor are thus similar in the vehicle safety investigation for knee ligament injury. Vehicle-center impact test results revealed that the tibia fracture assessments derived from the normalized tibia fracture measures did not significantly differ between the TRL legform impactor and the FLEX legform impactor. However, for an impact against an extremely stiff structure, there was a difference in the tibia fracture assessment between the FLEX legform impactor and the TRL legform impactor owing to their different sensor types. PMID:25178069

  14. Quasi-Uniform High Speed Foam Crush Testing Using a Guided Drop Mass Impact

    NASA Technical Reports Server (NTRS)

    Jones, Lisa E. (Technical Monitor); Kellas, Sotiris

    2004-01-01

    A relatively simple method for measuring the dynamic crush response of foam materials at various loading rates is described. The method utilizes a drop mass impact configuration with mass and impact velocity selected such that the crush speed remains approximately uniform during the entire sample crushing event. Instrumentation, data acquisition, and data processing techniques are presented, and limitations of the test method are discussed. The objective of the test method is to produce input data for dynamic finite element modeling involving crash and energy absorption characteristics of foam materials.

  15. MoSi2-Base Hybrid Composite Passed Engine Test

    NASA Technical Reports Server (NTRS)

    Keith, Theo G., Jr.; Hebsur, Mohan

    1998-01-01

    The intermetallics compound molybdenum disilicide (MoSi2) is an attractive high-temperature structural material for advanced engine applications. It has excellent oxidation resistance, a high melting point, relatively low density, and high thermal conductivity, and it is easily machined. Past research'at the NASA Lewis Research Center has resulted in the development of a hybrid composite consisting of a MoSi2 matrix reinforced with silicon nitride (Si3N4) Particulate and silicon carbide (SiC) fibers. This composite has demonstrated attractive strength, toughness, thermal fatigue, and oxidation resistance, including resistance to "pest" oxidation. These properties attracted the interest of the Office of Naval Research and Pratt & Whitney, and a joint NASA/Navy/Pratt & Whitney effort was developed to continue to mature the MoSi2 Composite technology. A turbine blade outer air seal, which was part of the Integrated High Performance Turbine Engine Technology (IHPTET) program, was chosen as a first component on which to focus. The first tasks of the materials development effort were to develop improved processing methods to reduce costs and to use fine-diameter fibers that enable the manufacturing of complex shapes. Tape-casting methods were developed to fully infiltrate the fine SiC fibers with matrix powders. The resulting composites were hot pressed to 100-percent density. Composites with cross-plied fiber architectures with 30 vol. % hi-nicalon SiC fibers and 30 vol. % nitride particles are now made routinely and demonstrate a good balance of properties. The next task entailed the measurement of a wide variety of mechanical properties to confirm the suitability of this composite in engines. In particular, participants in this effort demonstrated that composites made with Hi-Nicalon fibers had strength and toughness properties equal to or better than those of the composites made with the large-diameter fibers that had been used previously. Another critically important property measured was impact resistance. Aircraft engine components require sufficient toughness to resist manufacturing defects, assembly damage, stress concentrations at notches, and foreign object damage. Engine company designers indicated that impact resistance would have to be measured before they would seriously consider these types of composites. The Charpy V-notch test was chosen to assess impact resistance, and both monolithic and composite versions Of MOSi2 were tested from -300 to 1400 C. The results (see the following graphs) show that nitride-particulate-reinforced MoSi2 exhibited impact resistance higher than that of many monolithic ceramics and intermetallics, and that the fiber-reinforced composites had even higher values, approaching that of cast superalloys.

  16. Soil stiffness beneath a rigid mass using non-destructive impact testing

    E-print Network

    Maxwell, James Christopher

    1992-01-01

    locations at the landfill. Larger spread footings having areas from 3. 25 to 9. 44 m' and embedded in clay were also tested. A simplified single-degree-of-freedom model with a mass, spring and dashpot, was used to model the footing-soil systems. Static... load tests were also performed to prove or disprove the impact test's credibility in determining static stiffnesses from the dynamic test. DEDICATION This thesis is dedicated to my wife, Mary Beth, who has provided me with continual support...

  17. A Comparison of Quasi-Static Indentation and Drop-Weight Impact Testing on Carbon/Epoxy Laminates

    NASA Technical Reports Server (NTRS)

    Prabhakaran, R.; Douglas, Michael J.

    2000-01-01

    This project was initiated to investigate the damage tolerance of polymer matrix composites (PMC). After a low velocity impact-such as the ones that can occur during manufacturing or service there is usually very little visual damage. There are two possible methods to simulate foreign object impact on PMC: static indentation and drop weight impact. A static method for modeling low velocity foreign object impact events for composites can prove to be very beneficial to researchers since much more data can be obtained from a static test than from an impact test. In order to examine if this is feasible, a series of static indentation and low velocity impact tests were performed and compared. Square specimens of different sizes and thicknesses were tested to cover a wide array of low velocity impact events. Laminates with a 45 degree stacking sequence were used since this is a common type of engineering laminate. Three distinct flexural rigidities under two different boundary conditions were tested in order to obtain damage due to large deflections. Comparisons between static indentation and low velocity impact tests were based on the maximum applied transverse load. The dependent parameters examined were dent depth, back surface crack length, delamination area, and load-deflection behavior. Results showed that no distinct differences could be seen between the static indentation tests and the low velocity impact tests, indicating that static indentation tests can be used to simulate low velocity impact events.

  18. 1 year test-retest reliability of ImPACT in professional ice hockey players.

    PubMed

    Bruce, Jared; Echemendia, Ruben; Meeuwisse, Willem; Comper, Paul; Sisco, Amber

    2014-01-01

    The Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) battery is widely used to assess neurocognitive outcomes following sports-related concussion. The purpose of this study was to examine the 1 year test-retest reliability of ImPACT in a multilingual sample of professional hockey players. A total of 305 professional hockey players were tested 1 year apart using ImPACT. Reliable change confidence intervals were calculated and test-retest reliability was measured using Pearson and Intraclass correlation coefficients. Results indicated that the 1-year test-retest reliabilities for the Visual Motor and Reaction Time Composites ranged from low to high (.52 to .81). In contrast, 1-year test-retest reliabilities for the Verbal and Visual Memory Composites were low (.22 to .58). The 1-year test-retest results provided mixed support for the use of Visual Motor and Reaction Time Composites in select samples; in contrast, the Verbal and Visual Memory Composites may not be sensitive to clinical change. PMID:24345194

  19. A comparative evaluation of in-plane shear test methods for laminated graphite-epoxy composites

    NASA Technical Reports Server (NTRS)

    Morton, John; Ho, Henjen

    1992-01-01

    The objectives were to evaluate popular shear test methods for various forms of graphite-epoxy composite materials and to determine the shear response of graphite-epoxy composites with various forms of fiber architecture. Numerical and full-field experimental stress analyses were performed on four shear test configurations for unidirectional and bidirectional graphite-epoxy laminates to assess the uniformity and purity of the shear stress (strain) fields produced in the specimen test section and to determine the material in-plane shear modulus and shear response. The test methods were the 10 deg off-axis, the +/- 45 deg tension, the Iosipescu V-notch, and a compact U-notch specimen. Specimens were prepared from AS4/3501-6 graphite-epoxy panels, instrumented with conventional strain gage rosettes and with a cross-line moire grating, and loaded in a convenient testing machine. The shear responses obtained for each test method and the two methods of specimen instrumentation were compared. In a second phase of the program the shear responses obtained from Iosipescu V-notch beam specimens were determined for woven fabric geometries of different weave and fiber architectures. Again the responses of specimens obtained from strain gage rosettes and moire interferometry were compared. Additional experiments were performed on a bidirectional cruciform specimen which was also instrumented with strain gages and a moire grating.

  20. PV module degradation caused by thermomechanical stress: real impacts of outdoor weathering versus accelerated testing in the laboratory

    Microsoft Academic Search

    W. Herrmann; N. Bogdanski; F. Reil; M. Köhl; K.-A. Weiss; M. Assmus; M. Heck

    2010-01-01

    Temperature cycling tests are part of the IEC 61215 qualification testing of crystalline silicon (c-Si) PV modules for evaluating PV module degradation caused by the impact of thermo-mechanically induced stresses. The defined temperature gradient and the cycle time by far exceed the actual impact of natural weathering, however. As a contribution to comparisons between laboratory testing and natural weathering our

  1. Measuring Student Achievement: The Impact of Standardized Testing on Equity and Excellence in Mathematics. Weaving Gender Equity into Math Reform.

    ERIC Educational Resources Information Center

    TERC, Cambridge, MA.

    This paper describes how to conduct a session to address the increasing presence of standardized testing and its impact on reform in mathematics classrooms. A brief history of testing and the impact of testing on teaching and learning are presented. Focusing on the consequences for educational equity that come from conducting state and national…

  2. Responses of 3D biaxial spacer weft-knitted composite circular plate under impact loading. Part II: impact tests and FEM calculation

    Microsoft Academic Search

    J. J. Li; B. Z. Sun; H. Hu; B. H. Gu

    2010-01-01

    The responses of 3D biaxial spacer weft-knitted composite circular plate under impact loading had been investigated both in experimental and finite-element analysis (FEA). The impact tests were carried out with a modified split Hopkinson pressure bar (SHPB) apparatus and copared with the results from the quasi-static indentation tests. The load–displacement curves of the composite circular plate under impact were obtained

  3. HE friction sensitivity oblique impact sensitivity of explosives (the SKID test). Progress report, October 1971--December 1971

    SciTech Connect

    Van Velkinburgh, J.H.

    1998-12-31

    The oblique impact test series on LX-10-0 Lot 710-2 was completed. Two instrumented oblique impact tests were done using RX-04-DW dropped at 45{degrees}, 5{prime} on a smooth steel surface. One additional oblique impact using RX-04-EB at 45{degrees} 3.5{prime} was done. An instrumented vertical drop and oblique impact series was begun on RX-04-EC (96/4 HMX/Viton).

  4. Impact Analyses and Tests of Metal Cask Considering Aircraft Engine Crash - 12308

    SciTech Connect

    Lee, Sanghoon; Choi, Woo-Seok; Kim, Ki-Young; Jeon, Je-Eon; Seo, Ki-Seog [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-07-01

    The structural integrity of a dual purpose metal cask currently under development by the Korea Radioactive Waste Management Cooperation (KRMC) is evaluated through analyses and tests under a high-speed missile impact considering the targeted aircraft crash conditions. The impact conditions were carefully chosen through a survey on accident cases and recommendations from the literature. The missile impact velocity was set at 150 m/s, and two impact orientations were considered. A simplified missile simulating a commercial aircraft engine is designed from an impact load history curve provided in the literature. In the analyses, the focus is on the evaluation of the containment boundary integrity of the metal cask. The analyses results are compared with the results of tests using a 1/3 scale model. The results show very good agreements, and the procedure and methodology adopted in the structural analyses are validated. While the integrity of the cask is maintained in one evaluation where the missile impacts the top side of the free standing cask, the containment boundary is breached in another case in which the missile impacts the center of the cask lid in a perpendicular orientation. A safety assessment using a numerical simulation of an aircraft engine crash into spent nuclear fuel storage systems is performed. A commercially available explicit finite element code is utilized for the dynamic simulation, and the strain rate effect is included in the modeling of the materials used in the target system and missile. The simulation results show very good agreement with the test results. It is noted that this is the first test considering an aircraft crash in Korea. (authors)

  5. What’s the Point? How Point-of-Care STI Tests Can Impact Infected Patients

    PubMed Central

    Huppert, Jill; Hesse, Elizabeth; Gaydos, Charlotte A.

    2010-01-01

    Point-of-care (POC) tests are an important strategy to address the epidemic of sexually transmitted infections (STIs) among both adolescents and young adults. While access to care and confidentiality are major barriers to STI care, POC tests allow the clinician to provide immediate and confidential test results and treatment. In addition, POC test results constitute a “teachable moment”; that is, an opportunity to provide immediate feedback to the patient that may impact his/her risk behaviors. This paper reviews published data and manufacturer’s product literature describing current point-of-care STI tests, including studies of test performance as well as impact on treatment intervals and disease spread. It presents theoretical and proposed pitfalls and solutions of implementing POC tests in clinical settings, non-traditional settings, and home care venues. We reviewed the available STI tests according to the World Health Organization (WHO) criteria for judging POC tests: the “ASSURRED” criteria (Affordable, Sensitive, Specific, User-friendly, Rapid and Robust, Equipment-free, Delivered). PMID:20401167

  6. Low velocity impact tests of laminate glass-fiber-epoxy matrix composite material plates

    Microsoft Academic Search

    Giovanni Belingardi; Roberto Vadori

    2002-01-01

    This work deals with the characterization of composite material suitable for constructing structural parts devoted to dissipate kinetic energy during impacts. In particular glass-fiber-epoxy matrix laminates are considered, both with unidirectional layers and with woven layers stacking, with three different layers orientations.Experimental tests are performed according to ASTM standards using a free-fall drop dart testing machine. The specimens are plates

  7. Statistical variations in impact resistance of steel fiber-reinforced concrete subjected to drop weight test

    Microsoft Academic Search

    M. C. Nataraja; N. Dhang; A. P. Gupta

    1999-01-01

    The variation in impact resistance of steel fiber-reinforced concrete and plain concrete as determined from a drop weight test is reported. The observed coefficients of variation are about 57 and 46% for first-crack resistance and the ultimate resistance in the case of fiber concrete and the corresponding values for plain concrete are 54 and 51%, respectively. The goodness-of-fit test indicated

  8. Sensitivity and specificity of the ImPACT Test Battery for concussion in athletes

    Microsoft Academic Search

    Philip Schatz; Jamie E. Pardini; Mark R. Lovell; Michael W. Collins; Kenneth Podell

    2006-01-01

    This study explored the diagnostic utility of the composite scores of Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) and Post Concussion Symptom Scale scores (PCSS). Recently concussed high school athletes (N=72) were tested within 72h of sustaining a concussion, and data were compared to non-concussed high school athletes with no history of concussion (N=66). Between-groups MANOVA revealed a significant multivariate

  9. A small-scale test for fiber release from carbon composites. [pyrolysis and impact

    NASA Technical Reports Server (NTRS)

    Gilwee, W. J., Jr.; Fish, R. H.

    1980-01-01

    A test method was developed to determine relative fiber loss from pyrolyzed composites with different resins and fiber construction. Eleven composites consisting of woven and unwoven carbon fiber reinforcement and different resins were subjected to the burn and impact test device. The composites made with undirectional tape had higher fiber loss than those with woven fabric. Also, the fiber loss was inversely proportional to the char yield of the resin.

  10. Investigation and Comparison between New Satellite Impact Test Results and NASA Standard Breakup Model

    NASA Technical Reports Server (NTRS)

    Sakuraba, K.; Tsuruda, Y.; Hanada, T.; Liou, J.-C.; Akahoshi, Y.

    2007-01-01

    This paper summarizes two new satellite impact tests conducted in order to investigate on the outcome of low- and hyper-velocity impacts on two identical target satellites. The first experiment was performed at a low velocity of 1.5 km/s using a 40-gram aluminum alloy sphere, whereas the second experiment was performed at a hyper-velocity of 4.4 km/s using a 4-gram aluminum alloy sphere by two-stage light gas gun in Kyushu Institute of Technology. To date, approximately 1,500 fragments from each impact test have been collected for detailed analysis. Each piece was analyzed based on the method used in the NASA Standard Breakup Model 2000 revision. The detailed analysis will conclude: 1) the similarity in mass distribution of fragments between low and hyper-velocity impacts encourages the development of a general-purpose distribution model applicable for a wide impact velocity range, and 2) the difference in area-to-mass ratio distribution between the impact experiments and the NASA standard breakup model suggests to describe the area-to-mass ratio by a bi-normal distribution.

  11. High-speed impact test using an inertial mass and an optical interferometer.

    PubMed

    Jin, T; Watanabe, K; Prayogi, I A; Takita, A; Mitatha, S; Djamal, M; Jia, H Z; Hou, W M; Fujii, Y

    2013-07-01

    A high-speed impact testing method for evaluating mechanical properties of materials is proposed using an inertial mass and a dual beat-frequencies laser Doppler interferometer (DB-LDI). In this method, an inertial mass levitated using an aerostatic linear bearing is made to collide with the material being tested at a high initial velocity. During the collision, the velocity of the mass, which is even higher than the critical velocity (±0.56 m/s) defined by the frequency difference of the Zeeman laser, is accurately measured using the DB-LDI. The position, acceleration, and impact force of the mass are calculated from the measured velocity. Using the proposed method, the mechanical properties of a visco-elastic material under a high-speed impact loading condition can be accurately evaluated. PMID:23902115

  12. A low cost method of testing compression-after-impact strength of composite laminates

    NASA Technical Reports Server (NTRS)

    Nettles, Alan T.

    1991-01-01

    A method was devised to test the compression strength of composite laminate specimens that are much thinner and wider than other tests require. The specimen can be up to 7.62 cm (3 in) wide and as thin as 1.02 mm (.04 in). The best features of the Illinois Institute of Technology Research Institute (IITRI) fixture are combined with an antibuckling jig developed and used at the University of Dayton Research Institute to obtain a method of compression testing thin, wide test coupons on any 20 kip (or larger) loading frame. Up to 83 pct. less composite material is needed for the test coupons compared to the most commonly used compression-after-impact (CAI) tests, which calls for 48 ply thick (approx. 6.12 mm) test coupons. Another advantage of the new method is that composite coupons of the exact lay-up and thickness of production parts can be tested for CAI strength, thus yielding more meaningful results. This new method was used to compression test 8 and 16 ply laminates of T300/934 carbon/epoxy. These results were compared to those obtained using ASTM standard D 3410-87 (Celanese compression test). CAI testing was performed on IM6/3501-6, IM7/SP500 and IM7/F3900. The new test method and associated fixture work well and is a valuable asset to MSFC's damage tolerance program.

  13. Compression and impact testing of two-layer composite pyramidal-core sandwich panels

    E-print Network

    Vaziri, Ashkan

    Compression and impact testing of two-layer composite pyramidal-core sandwich panels Jian Xiong a.e., with different relative densities) were fabricated: 1.25%, 1.81%, and 2.27%. Two-layer sandwich panels Sandwich panels with low-density cores have attracted signifi- cant interest as multifunctional structures

  14. The ‘Power Test’: its impact on student learning in a materials science course for engineering students

    Microsoft Academic Search

    Caroline Baillie; Susan Toohey

    1997-01-01

    This paper explores the impact on students’ learning of a change in assessment in a materials science course for engineers. The theory behind the move is discussed with reference to previous work on developing deeper approaches to learning in students at university. The new concept adopted was a ‘power test‘ — an open book format final exam, with extended time

  15. A unique facility for V/STOL aircraft hover testing. [Langley Impact Dynamics Research Facility

    NASA Technical Reports Server (NTRS)

    Culpepper, R. G.; Murphy, R. D.; Gillespie, E. A.; Lane, A. G.

    1979-01-01

    The Langley Impact Dynamics Research Facility (IDRF) was modified to obtain static force and moment data and to allow assessment of aircraft handling qualities during dynamic tethered hover flight. Test probe procedures were also established. Static lift and control measurements obtained are presented along with results of limited dynamic tethered hover flight.

  16. Impact of genetic testing on causal models of heart disease and arthritis: An analogue study

    Microsoft Academic Search

    Victoria Senior; Theresa M. Marteau; John Weinman

    2000-01-01

    An analogue study investigated the impact of genetic testing on perceptions of disease. Using a 2 × 2 design, participants (n = 212) imagined receiving the information that they were at increased risk for either heart disease or arthritis. The type of risk information was either genetic or unspecified. Presentation of genetic risk information resulted in the condition being perceived

  17. On the modeling of the Taylor cylinder impact test for orthotropic textured materials: experiments and simulations

    Microsoft Academic Search

    P. J. Maudlin; J. F. Bingert; J. W. House; S. R. Chen

    1999-01-01

    Taylor impact tests using specimens cut from a rolled plate of tantalum were conducted. The tantalum was experimentally characterized in terms of flow stress and crystallographic texture. A piece-wise yield surface was interrogated from an ODF corresponding to this texture assuming two slip system modes, in conjunction with an elastic stiffness tensor computed from the same ODF and single crystal

  18. Teacher Voices: The Impact of High-Stakes Testing on Teacher Caring

    ERIC Educational Resources Information Center

    Wellman, Nelda

    2007-01-01

    This study examined the impact of the high-stakes testing on caring practices from the perspectives of teachers in Grades 3 and 5. These teachers, located in an East Texas school district with high percentages of low socioeconomic students, were identified as caring practitioners by their respective principals. Through the qualitative method of…

  19. The Overall Impact of Testing on Medical Student Learning: Quantitative Estimation of Consequential Validity

    ERIC Educational Resources Information Center

    Kreiter, Clarence D.; Green, Joseph; Lenoch, Susan; Saiki, Takuya

    2013-01-01

    Given medical education's longstanding emphasis on assessment, it seems prudent to evaluate whether our current research and development focus on testing makes sense. Since any intervention within medical education must ultimately be evaluated based upon its impact on student learning, this report seeks to provide a quantitative accounting of…

  20. Alignment Errors Strongly Impact Likelihood-Based Tests for Comparing Topologies

    E-print Network

    Pupko, Tal

    Article Alignment Errors Strongly Impact Likelihood-Based Tests for Comparing Topologies Eli Levy Karin,1 Edward Susko,*,2 and Tal Pupko*,1 1 Department of Cell Research and Immunology, George S. Wise of alignment error and can lead to erroneous conclusions. Using simulations we demonstrated that due

  1. Testing Younger Dryas ET Impact (YDB) Evidence at Hall's Cave, Texas

    Microsoft Academic Search

    T. W. Stafford; E. Lundelius; J. Kennett; D. J. Kennett; W. S. Wolbach

    2009-01-01

    Hall's Cave, Kerrville County Texas, 167 km WSW of Austin, provides a unique opportunity for testing the presence of a chronostratigraphic datum (YDB layer) containing rare and exotic proxies, including nanodiamonds, aciniform soot, and magnetic spherules, the origins of which remain controversial, but possibly derive from a cosmic impact ~12,900 CAL BP. The karst-collapse cave in Cretaceous limestone on the

  2. The Impact of Specification Error on the Estimation, Testing, and Improvement of Structural Equation Models

    Microsoft Academic Search

    David Kaplan

    1988-01-01

    The purpose of this paper is to assess the impact of misspecification on the estimation, testing, and improvement of structural equation models. A population study is con- ducted whereby a prototypical latent variable model is misspecified in various ways. Measurement model and structural model misspecifications are considered separately and together. The maximum likelihood estimator (ML) is compared to a limited

  3. Laboratory wind tunnel testing of three commonly used saltation impact sensors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Electronic sensors that record individual impacts from saltating particles are used with increasing frequency in wind erosion field studies. Little is known about the limitations of these instruments or comparability of data collected with them. We tested the three most commonly used Saltation Imp...

  4. Impact Dynamics Analysis and Laboratory Test of FOPS for Engineering Vehicle

    Microsoft Academic Search

    J. X. Wang; X. B. Tang; D. Y. Lin; S. L. Feng

    2010-01-01

    In order to shorten the design cycle of FOPS and improve the pass rate of FOPS laboratory destructive tests, nonlinear finite element methods of elastic-plastic large displacement were presented to simulate the dynamic displacement, velocity and acceleration of drop hammer during impact process, and the dynamic changing law of these parameters during the whole collision were analyzed. At the same

  5. The impact of drug testing on the morale and well-being of mandatory participants.

    PubMed

    Coombs, R H; Coombs, C J

    1991-09-01

    The impact of drug testing on the morale of mandatory participants was assessed through interviews and questionnaire responses of 500 intercollegiate athletes required to participate in a urine testing program. Subjects varied widely in their experiences. Most were not greatly affected, but some were embarrassed, humiliated, upset, and anxious about being inaccurately identified as drug users. Others experienced positive benefits: new information, a novel and interesting conversation piece, and a socially acceptable way to refuse drugs offered in friendship. Some said that testing benefited their athletic performance and school work. A number of recommendations were made to humanize and improve the experience: a better orientation about what to expect, more effective educational sessions, a warmer, more comfortable testing setting, more reasonable drug testing objectives, and more rigorous testing standards. PMID:1743826

  6. Low amplitude impact testing and analysis of pristine and aged solid high explosives

    SciTech Connect

    Chidester, S K; Garza, R; Tarver, C M

    1998-08-17

    The critical impact velocities of 60.1 mm diameter blunt steel projectiles required for ignition of exothermic chemical reaction were determined for heavily confined charges of new and aged (15-30 years) solid HMX-based high explosives. The explosives in order of decreasing impact sensitivity were: PBX 9404; LX-lo; LX-14; PBX 9501; and LX-04. Embedded pressure gauges measured the interior pressure histories. Stockpile aged LX-04 and PBX 9501 from dismantled units were tested and compared to freshly pressed charges. The understanding of explosive aging on impact ignition and other hazards must improve as systems are being deployed longer than their initial estimated lifetimes. The charges that did not react on the first impact were subjected to multiple impacts. While the violence of reaction increased with impact velocity, it remained much lower than that produced by an intentional detonation. Ignition and Growth reactive flow models were developed to predict HMX-based explosive impact sensitivity in other geometries and scenarios.

  7. Elemental Water Impact Test: Phase 3 Plunge Depth of a 36-Inch Aluminum Tank Head

    NASA Technical Reports Server (NTRS)

    Vassilakos, Gregory J.

    2014-01-01

    Spacecraft are being designed based on LS-DYNA water landing simulations. The Elemental Water Impact Test (EWIT) series was undertaken to assess the accuracy of LS-DYNA water impact simulations. Phase 3 featured a composite tank head that was tested at a range of heights to verify the ability to predict structural failure of composites. To support planning for Phase 3, a test series was conducted with an aluminum tank head dropped from heights of 2, 6, 10, and 12 feet to verify that the test article would not impact the bottom of the test pool. This report focuses on the comparisons of the measured plunge depths to LS-DYNA predictions. The results for the tank head model demonstrated the following. 1. LS-DYNA provides accurate predictions for peak accelerations. 2. LS-DYNA consistently under-predicts plunge depth. An allowance of at least 20% should be added to the LS-DYNA predictions. 3. The LS-DYNA predictions for plunge depth are relatively insensitive to the fluid-structure coupling stiffness.

  8. Impact Testing of Stainless Steel Material at Room and Elevated Temperatures

    SciTech Connect

    Dana K. Morton; Spencer D. Snow; Tom E. Rahl; Robert K. Blandford

    2007-07-01

    Stainless steels are used for the construction of numerous spent nuclear fuel or radioactive material containers that may be subjected to high strains and moderate strain rates during accidental drop events. Mechanical characteristics of these base materials and their welds under dynamic loads in the strain rate range of concern are not well documented. However, three previous papers [1, 2, 3] reported on impact testing and analysis results performed at the Idaho National Laboratory using 304/304L and 316/316L stainless steel base material specimens that began the investigation of these characteristics. The goal of the work presented herein is to add the results of additional tensile impact testing for 304/304L and 316/316L stainless steel material specimens. Utilizing a drop-weight impact test machine and 1/4-inch to 1/2-inch thick dog-bone shaped test specimens, additional tests achieved target strain rates of 5, 10, and 22 per second at room temperature, 300, and 600 degrees Fahrenheit. Elevated true stress-strain curves for these materials at each designated strain rate and temperature are presented herein.

  9. Simulation of an Impact Test of the All-Composite Lear Fan Aircraft

    NASA Technical Reports Server (NTRS)

    Stockwell, Alan E.; Jones, Lisa E. (Technical Monitor)

    2002-01-01

    An MSC.Dytran model of an all-composite Lear Fan aircraft fuselage was developed to simulate an impact test conducted at the NASA Langley Research Center Impact Dynamics Research Facility (IDRF). The test was the second of two Lear Fan impact tests. The purpose of the second test was to evaluate the performance of retrofitted composite energy-absorbing floor beams. A computerized photogrammetric survey was performed to provide airframe geometric coordinates, and over 5000 points were processed and imported into MSC.Patran via an IGES file. MSC.Patran was then used to develop the curves and surfaces and to mesh the finite element model. A model of the energy-absorbing floor beams was developed separately and then integrated into the Lear Fan model. Structural responses of components such as the wings were compared with experimental data or previously published analytical data wherever possible. Comparisons with experimental results were used to guide structural model modifications to improve the simulation performance. This process was based largely on qualitative (video and still camera images and post-test inspections) rather than quantitative results due to the relatively few accelerometers attached to the structure.

  10. Impacts of four communication programs on HIV testing behavior in South Africa.

    PubMed

    Do, Mai; Kincaid, D Lawrence; Figueroa, Maria Elena

    2014-01-01

    This paper aims to evaluate the impacts of four communication programs on promoting HIV testing behavior among sexually active individuals in South Africa. The four programs, implemented by Johns Hopkins Health and Education in South Africa, are aimed to promote HIV prevention behaviors, as well as gender-based violence prevention, tuberculosis screening and treatment, and reduction of alcohol consumption. Launched between 2009 and 2010, they all promoted HIV testing. Data came from the population-based Third National AIDS Communication Survey 2012; 6004 men and women who had sex within the last 12 months were included in the analysis. Multiple causal attribution analysis is used to justify causal reference and estimate the impact of communication programs. Findings indicate significant direct and indirect effects of the programs on HIV testing behavior. Indirect effects worked through increasing one's likelihood of perceiving that their friends were tested and the probability of talking about HIV testing with sex partners and friends, which in turn increased the likelihood of HIV testing. Findings suggest multiple angles from which communication programs can promote HIV testing. The study also demonstrates the use of multiple statistical techniques for causal attribution in a post-only design, where randomization is not possible. PMID:24702270

  11. Insights Into Correlation Between Board-Level Drop Reliability and Package-Level Ball Impact Test Characteristics

    Microsoft Academic Search

    Chang-Lin Yeh; Yi-Shao Lai

    2007-01-01

    The ball impact test (BIT) is developed based on the demand of a package-level measure for the board-level drop reliability of solder joints in the sense that it leads to fracturing of solder joints around the intermetallics, similar to that from a board-level drop test. In this paper, both board-level drop test and package-level ball impact test are examined numerically

  12. ACTUAL WASTE TESTING OF GYCOLATE IMPACTS ON THE SRS TANK FARM

    SciTech Connect

    Martino, C.

    2014-05-28

    Glycolic acid is being studied as a replacement for formic acid in the Defense Waste Processing Facility (DWPF) feed preparation process. After implementation, the recycle stream from DWPF back to the high-level waste Tank Farm will contain soluble sodium glycolate. Most of the potential impacts of glycolate in the Tank Farm were addressed via a literature review and simulant testing, but several outstanding issues remained. This report documents the actual-waste tests to determine the impacts of glycolate on storage and evaporation of Savannah River Site high-level waste. The objectives of this study are to address the following: ? Determine the extent to which sludge constituents (Pu, U, Fe, etc.) dissolve (the solubility of sludge constituents) in the glycolate-containing 2H-evaporator feed. ? Determine the impact of glycolate on the sorption of fissile (Pu, U, etc.) components onto sodium aluminosilicate solids. The first objective was accomplished through actual-waste testing using Tank 43H and 38H supernatant and Tank 51H sludge at Tank Farm storage conditions. The second objective was accomplished by contacting actual 2H-evaporator scale with the products from the testing for the first objective. There is no anticipated impact of up to 10 g/L of glycolate in DWPF recycle to the Tank Farm on tank waste component solubilities as investigated in this test. Most components were not influenced by glycolate during solubility tests, including major components such as aluminum, sodium, and most salt anions. There was potentially a slight increase in soluble iron with added glycolate, but the soluble iron concentration remained so low (on the order of 10 mg/L) as to not impact the iron to fissile ratio in sludge. Uranium and plutonium appear to have been supersaturated in 2H-evaporator feed solution mixture used for this testing. As a result, there was a reduction of soluble uranium and plutonium as a function of time. The change in soluble uranium concentration was independent of added glycolate concentration. The change in soluble plutonium content was dependent on the added glycolate concentration, with higher levels of glycolate (5 g/L and 10 g/L) appearing to suppress the plutonium solubility. The inclusion of glycolate did not change the dissolution of or sorption onto actual-waste 2H-evaporator pot scale to an extent that will impact Tank Farm storage and concentration. The effects that were noted involved dissolution of components from evaporator scale and precipitation of components onto evaporator scale that were independent of the level of added glycolate.

  13. Spin Testing for Durability Began on a Self-Tuning Impact Damper for Turbomachinery Blades

    NASA Technical Reports Server (NTRS)

    Duffy, Kirsten; Mehmed, Oral

    2003-01-01

    NASA and Pratt & Whitney will collaborate under a Space Act Agreement to perform spin testing of the impact damper to verify damping effectiveness and durability. Pratt & Whitney will provide the turbine blade and damper hardware for the tests. NASA will provide the facility and perform the tests. Effectiveness and durability will be investigated during and after sustained sweeps of rotor speed through resonance. Tests of a platform wedge damper are also planned to compare its effectiveness with that of the impact damper. Results from baseline tests without dampers will be used to measure damping effectiveness. The self-tuning impact damper combines two damping methods-the tuned mass damper and the impact damper. It consists of a ball located within a cavity in the blade. This ball rolls back and forth on a spherical trough under centrifugal load (tuned mass damper) and can strike the walls of the cavity (impact damper). The ball s rolling natural frequency is proportional to the rotor speed and can be designed to follow an engine-order line (integer multiple of rotor speed). Aerodynamic forcing frequencies typically follow these engineorder lines, and a damper tuned to the engine order will most effectively reduce blade vibrations when the resonant frequency equals the engine-order forcing frequency. This damper has been tested in flat plates and turbine blades in the Dynamic Spin Facility. During testing, a pair of plates or blades rotates in vacuum. Excitation is provided by one of three methods--eddy-current engine-order excitation (ECE), electromechanical shakers, and magnetic bearing excitation. The eddy-current system consists of magnets located circumferentially around the rotor. As a blade passes a magnet, a force is imparted on the blade. The number of magnets used can be varied to change the desired engine order of the excitation. The magnets are remotely raised or lowered to change the magnitude of the force on the blades. The other two methods apply force to the rotating shaft itself at frequencies independent of the rotor speed. During testing, blade vibration is monitored with strain gauges and laser displacement probes.

  14. Carleton University, TR SCE-02-04, Version 2 August 2003 Automating Impact Analysis and Regression Test

    E-print Network

    Carleton University

    their impacts on test cases. A drawback is that it requires that the changes be already implemented but it canCarleton University, TR SCE-02-04, Version 2 August 2003 Automating Impact Analysis and Regression Test Selection Based on UML Designs L. C. Briand, Y. Labiche, K. Buist, G. Soccar Software Quality

  15. Enhancements in Magnesium Die Casting Impact Properties

    SciTech Connect

    David Schwam; John F. Wallace; Yulong Zhu; Srinath Viswanathan; Shafik Iskander

    2000-06-30

    The need to produce lighter components in transportation equipment is the main driver in the increasing demand for magnesium castings. In many automotive applications, components can be made of magnesium or aluminum. While being lighter, often times the magnesium parts have lower impact and fatigue properties than the aluminum. The main objective of this study was to identify potential improvements in the impact resistance of magnesium alloys. The most common magnesium alloys in automotive applications are AZ91D, AM50 and AM60. Accordingly, these alloys were selected as the main candidates for the study. Experimental quantities of these alloys were melted in an electrical furnace under a protective atmosphere comprising sulfur hexafluoride, carbon dioxide and dry air. The alloys were cast both in a permanent mold and in a UBE 315 Ton squeeze caster. Extensive evaluation of tensile, impact and fatigue properties was conducted at CWRU on permanent mold and squeeze cast test bars of AZ91, AM60 and AM50. Ultimate tensile strength values between 20ksi and 30ksi were obtained. The respective elongations varied between 25 and 115. the Charpy V-notch impact strength varied between 1.6 ft-lb and 5 ft-lb depending on the alloy and processing conditions. Preliminary bending fatigue evaluation indicates a fatigue limit of 11-12 ksi for AM50 and AM60. This is about 0.4 of the UTS, typical for these alloys. The microstructures of the cast specimens were investigated with optical and scanning electron microscopy. Concomitantly, a study of the fracture toughness in AM60 was conducted at ORNL as part of the study. The results are in line with values published in the literature and are representative of current state of the art in casting magnesium alloys. The experimental results confirm the strong relationship between aluminum content of the alloys and the mechanical properties, in particular the impact strength and the elongation. As the aluminum content increases from about 5% in AM50 to over 9% in AZ91, more of the intermetallic Mg17Al12 is formed in the microstructure. For instance, for 15 increase in the aluminum content from AM50 to AM60, the volume fraction of eutectic present in the microstructure increases by 35%! Eventually, the brittle Mg17Al12 compound forms an interconnected network that reduces ductility and impact resistance. The lower aluminum in AM50 and AM60 are therefore a desirable feature in applications that call for higher impact resistance. Further improvement in impact resistance depends on the processing condition of the casting. Sound castings without porosity and impurities will have better mechanical properties. Since magnesium oxidizes readily, good melting and metal transfer practices are essential. The liquid metal has to be protected from oxidation at all times and entrainment of oxide films in the casting needs to be prevented. In this regard, there is evidence that us of vacuum to evacuate air from the die casting cavity can improve the quality of the castings. Fast cooling rates, leading to smaller grain size are beneficial and promote superior mechanical properties. Micro-segregation and banding are two additional defect types often encountered in magnesium alloys, in particular in AZ91D. While difficult to eliminate, segregation can be minimized by careful thermal management of the dies and the shot sleeve. A major source of segregation is the premature solidification in the shot sleeve. The primary solid dendrites are carried into the casting and form a heterogeneous structure. Furthermore, during the shot, segregation banding can occur. The remedies for this kind of defects include a hotter shot sleeve, use of insulating coatings on the shot sleeve and a short lag time between pouring into the shot sleeve and the shot.

  16. Accountability and Teacher Practice: Investigating the Impact of a New State Test and the Timing of State Test Adoption on Teacher Time Use

    ERIC Educational Resources Information Center

    Cocke, Erin F.; Buckley, Jack; Scott, Marc A.

    2011-01-01

    There is much debate over the impact of high stakes testing as well as a growing body of research focused on both the intended and unintended consequences of these tests. One claim of both the popular media and education researchers is that high stakes tests have led to curricular narrowing--the idea that school time is increasingly allocated to…

  17. An 810 ft/sec soil impact test of a 2-foot diameter model nuclear reactor containment system

    NASA Technical Reports Server (NTRS)

    Puthoff, R. L.

    1972-01-01

    A soil impact test was conducted on a 880-pound 2-foot diameter sphere model. The impact area consisted of back filled desert earth and rock. The impact generated a crater 5 feet in diameter by 5 feet deep. It buried itself a total of 15 feet - as measured to the bottom of the model. After impact the containment vessel was pressure checked. No leaks were detected nor cracks observed.

  18. Testing impact attenuation on California playground surfaces made of recycled tires.

    PubMed

    Vidair, Charles; Haas, Robert; Schlag, Robert

    2007-12-01

    This study was conducted to determine whether rubberized playground surfaces made of recycled tires comply with state-mandated standards for impact attenuation (measured with an accelerometer), and whether their properties change in response to temperature or time. The Head Impact Criterion (HIC) standard of 1000 was found to be a more sensitive indicator of compliance than the G(max) standard of 200(g). Of 32 playgrounds tested, 22 (69 percent) failed the HIC standard. As the heights of playground structures increased, so did the likelihood that the rubberized surface below would fail the HIC standard. Rubberized surfaces gave stable readings for the first three months following installation, and higher values in response to increasing surface temperature. An excessively high percentage of playground surfaces made of recycled tires failed the state-mandated standards designed to prevent serious head injury from falls. Future failures might be prevented by requiring installers to perform post-installation testing to verify compliance. PMID:18075871

  19. Environmental impact assessment of tailings dispersal from a uranium mine using toxicity testing protocols

    SciTech Connect

    Rippon, G.D. [Environmental Protection Agency, Canberra (Australia); Riley, S.J. [Univ. of Western Sydney-Nepean, Kingswood (Australia)

    1996-12-01

    Toxicity testing is a means of establishing the environmental risk of uranium tailings release. It is valuable in designing tailings containment structures because it assists in setting acceptable levels of risk of the design. This paper presents details of toxicity tests of the tailings from Ranger Uranium Mine, Northern Territory, Australia. The results suggest that the non-radiological toxicity of the tailings is low. The environmental risk of a tailings release is more likely to be related to the physical impacts of the tailings, including infilling of billabongs and changes in the sedimentology of riparian ecosystems rather than their biogeochemical impact. Two major results were: (1) water from treatment with washed tailing fines was not toxic to Hydra viridissima, and (2) mixtures of washed tailings fines and natural floodplain sediment (overlying water or elutriates) were not toxic to Hydra viridissima or Moinodaphnia macleayi. 33 refs., 4 figs., 3 tabs.

  20. Threshold Studies on TNT, Composition B, and C-4 Explosives Using the Steven Impact Test

    SciTech Connect

    Vandersall, K S; Switzer, L L; Garcia, F

    2005-09-26

    Steven Impact Tests were performed at low velocity on the explosives TNT, Comp B, and C-4 in attempts to obtain a threshold for reaction. A 76 mm helium driven gas gun was used to accelerate the Steven Test projectiles up to approximately 200 m/s in attempts to react (ignite) the explosive samples. Blast overpressure gauges, acoustic microphones, standard video and high-speed photography were used to characterize the level of any high explosive reaction violence. No bulk reactions were observed in the TNT, Composition B, or C-4 explosive samples impacted up to velocities in the range of 190-200 m/s. This work will outline the experimental details and discuss the lack of reaction when compared to the reaction thresholds of other common explosives.

  1. Preliminary burn and impact tests of hybrid polymeric composites. [preventing graphite fiber release

    NASA Technical Reports Server (NTRS)

    Tompkins, S. S.; Brewer, W. D.

    1978-01-01

    Free graphite fibers released into the environment from resin matrix composite components, as a result of fire and/or explosion, pose a potential hazard to electrical equipment. An approach to prevent the fibers from becoming airborne is to use hybrid composite materials which retain the fibers at the burn site. Test results are presented for three hybrid composites that were exposed to a simulation of an aircraft fire and explosion. The hybrid systems consisted of 16 plies of graphite-epoxy with two plies of Kevlar-, S-glass-, or boron-epoxy on each face. Two different test environments were used. In one environment, specimens were heated by convection only, and then impacted by a falling mass. In the other environment, specimens were heated by convection and by radiation, but were not impacted. The convective heat flux was about 100-120 kW/m in both environments and the radiative flux was about 110 kW/sq m.

  2. Experimental and Modeling Studies of Crush, Puncture, and Perforation Scenarios in the Steven Impact Test

    SciTech Connect

    Vandersall, K S; Chidester, S K; Forbes, J W; Garcia, F; Greenwood, D W; Switzer, L L; Tarver, C M

    2002-06-28

    The Steven test and associated modeling has greatly increased the fundamental knowledge of practical predictions of impact safety hazards for confined and unconfined explosive charges. Building on a database of initial work, experimental and modeling studies of crush, puncture, and perforation scenarios were investigated using the Steven impact test. The descriptions of crush, puncture, and perforation arose from safety scenarios represented by projectile designs that ''crush'' the energetic material or either ''puncture'' with a pinpoint nose or ''perforate'' the front cover with a transportation hook. As desired, these scenarios offer different aspects of the known mechanisms that control ignition: friction, shear and strain. Studies of aged and previously damaged HMX-based high explosives included the use of embedded carbon foil and carbon resistor gauges, high-speed cameras, and blast wave gauges to determine the pressure histories, time required for an explosive reaction, and the relative violence of those reactions, respectively. Various ignition processes were modeled as the initial reaction rate expression in the Ignition and Growth reaction rate equations. Good agreement with measured threshold velocities, pressure histories, and times to reaction was calculated for LX-04 impacted by several projectile geometries using a compression dependent ignition term and an elastic-plastic model with a reasonable yield strength for impact strain rates.

  3. Economic impact of a genetic test for cisplatin-induced ototoxicity.

    PubMed

    Dionne, F; Mitton, C; Rassekh, R; Brooks, B; Ross, C; Hayden, M; Carleton, B

    2012-06-01

    Cisplatin is a widely used chemotherapy drug in the treatment of pediatric solid tumors, but it is associated with significant rates of ototoxicity (medication-induced hearing loss). A genetic test has recently been developed that can help predict the likelihood that a cisplatin-treated pediatric patient will develop ototoxicity. This study estimates the potential economic impact of this test. Assuming that an alternative, non-preferred, medication to cisplatin exists that it is as efficacious as cisplatin but without the risk of hearing loss, and that the alternative treatment is no more expensive than current practice, we have estimated that administering this genetic test to every pediatric cancer patient for whom cisplatin is first-line therapy could potentially avoid an average of $71,168 in societal costs per tested patient. This translates into a potential present value savings of over $2.4 million annually in British Columbia and over $19.6 million in Canada. PMID:21502965

  4. Testing a Dynamic Complex Hypothesis in the Analysis of Land Use Impact on Lake Water Quality

    Microsoft Academic Search

    QingHai Guo; KeMing Ma; Liu Yang; Kate He

    2010-01-01

    In this study, we proposed a dynamic complex hypothesis that the impact of land use on water quality could vary along the\\u000a expansion of the buffer size, and there should be an effective buffer zone where the strongest linkage occurs between land\\u000a use and water quality. The hypothesis was tested and supported by a case study carried out in four

  5. Determination of dynamic fracture-initiation toughness using a novel impact bend test procedure

    Microsoft Academic Search

    T. Yokoyama

    1993-01-01

    A novel impact bend test procedure is described for determining the dynamic fracture-initiation toughness, K[sub Id], at a loading rate (stress intensity factor rate), K[sub I], of the order of 10[sup 6] MPa [radical]m\\/s. A special arrangement of the split Hopkinson pressure bar is adopted to measure accurately dynamic loads applied to a fatigue-precracked bend specimen. The dynamic stress intensity

  6. Energy absorption behavior of closed-cell aluminium foam under drop mass impact tests

    Microsoft Academic Search

    Fujun Yang; Siyuan Ni; Xiaoyuan He; Deping He

    2008-01-01

    Quasi-static axial compression and drop mass impact tests were performed to study the energy absorption behaviour of the closed-cell aluminium foam. Digital image analysis was firstly used to characterize the surface's structure of individual cells and aggregates of cells. The cell structure characterizations performed using the best-fit ellipse equivalent diameter for the individual cells, which included measurement of the size

  7. THRESHOLD STUDIES ON TNT, COMPOSITION B, C-4, AND ANFO EXPLOSIVES USING THE STEVEN IMPACT TEST

    Microsoft Academic Search

    K S Vandersall; L L Switzer; F Garcia

    2006-01-01

    Steven Impact Tests were performed at low velocity on the explosives TNT (trinitrotolulene), Composition B (63% RDX, 36% TNT, and 1% wax by weight), C-4 (91% RDX, 5.3% Di (2-ethylhexyl) sebacate, 2.1% Polyisobutylene, and 1.6% motor oil by weight) and ANFO (94% ammonium Nitrate with 6% Fuel Oil) in attempts to obtain a threshold for reaction. A 76 mm helium

  8. Charpy impact test results for unirradiated tantalum, tungsten and molybdenum alloys

    Microsoft Academic Search

    D. S. Gelles; N. S. Cannon; W. L. Hu; J. Hack

    1987-01-01

    Charpy impact tests have been performed on 1\\/2 sized CVN specimens of T-111, a tantalum based alloy, and two experimental alloys with rhenium additions for improved low temperature ductility, W-26Re and Mo-13Re. The tantalum alloy was found to have a ductile to brittle transition below \\/minus\\/175\\/degree\\/C whereas the rhenium containing alloys both had a DBTT above 250\\/degree\\/C. The high DBTT

  9. Space Shuttle solid rocket booster initial water impact loads and dynamics - Analysis, tests, and flight experience

    NASA Technical Reports Server (NTRS)

    Kross, D. A.; Kiefling, L. A.; Murphy, N. C.; Rawls, E. A.

    1983-01-01

    A series of scale model tests, finite element dynamic response analyses and full scale segment tests have been performed for purposes of developing design criteria for the initial water impact loading conditions applied to the internal stiffener rings located in the aft skirt portion of the Space Shuttle Solid Rocket Booster (SRB). In addition, flight experience has yielded information relative to structural reinforcement requirements. This paper discusses the test and analysis methods and summarizes significant results. It is noted that, although scale model test data are valuable for identifying trends, they have shortcomings concerning definition of full scale design loads criteria. Also, the frequently used static equivalent loads definition approach is not applicable for this type impact loading condition applied to an aft skirt type structure. Various types of ring structural fixes, including the addition of selected types of foam, are presented as well as associated full scale segment test results. Depending on the type and contour shape of the foam, reductions on applied pressures and peak measured strains over 50 percent are noted.

  10. THRESHOLD STUDIES ON TNT, COMPOSITION B, C-4, AND ANFO EXPLOSIVES USING THE STEVEN IMPACT TEST

    SciTech Connect

    Vandersall, K S; Switzer, L L; Garcia, F

    2006-06-20

    Steven Impact Tests were performed at low velocity on the explosives TNT (trinitrotolulene), Composition B (63% RDX, 36% TNT, and 1% wax by weight), C-4 (91% RDX, 5.3% Di (2-ethylhexyl) sebacate, 2.1% Polyisobutylene, and 1.6% motor oil by weight) and ANFO (94% ammonium Nitrate with 6% Fuel Oil) in attempts to obtain a threshold for reaction. A 76 mm helium driven gas gun was used to accelerate the Steven Test projectiles up to approximately 200 m/s in attempts to react (ignite) the explosive samples. Blast overpressure gauges, acoustic microphones, standard video and high-speed photography were used to characterize the level of any high explosive reaction violence. No bulk reactions were observed in the TNT, Composition B, C-4 or ANFO explosive samples impacted up to velocities in the range of 190-200 m/s. This work will outline the experimental details and discuss the lack of reaction when compared to the reaction thresholds of other common explosives. These results will also be compared to that of the Susan Test and reaction thresholds observed in the common small-scale safety tests such as the drop hammer and friction tests in hopes of drawing a correlation.

  11. Water Impact Test and Simulation of a Composite Energy Absorbing Fuselage Section

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Jackson, Karen E.; Sparks, Chad; Sareen, Ashish

    2003-01-01

    In March 2002, a 25-ft/s vertical drop test of a composite fuselage section was conducted onto water. The purpose of the test was to obtain experimental data characterizing the structural response of the fuselage section during water impact for comparison with two previous drop tests that were performed onto a rigid surface and soft soil. For the drop test, the fuselage section was configured with ten 100-lb. lead masses, five per side, that were attached to seat rails mounted to the floor. The fuselage section was raised to a height of 10-ft. and dropped vertically into a 15-ft. diameter pool filled to a depth of 3.5-ft. with water. Approximately 70 channels of data were collected during the drop test at a 10-kHz sampling rate. The test data were used to validate crash simulations of the water impact that were developed using the nonlinear, explicit transient dynamic codes, MSC.Dytran and LS-DYNA. The fuselage structure was modeled using shell and solid elements with a Lagrangian mesh, and the water was modeled with both Eulerian and Lagrangian techniques. The fluid-structure interactions were executed using the fast general coupling in MSC.Dytran and the Arbitrary Lagrange-Euler (ALE) coupling in LS-DYNA. Additionally, the smooth particle hydrodynamics (SPH) meshless Lagrangian technique was used in LS-DYNA to represent the fluid. The simulation results were correlated with the test data to validate the modeling approach. Additional simulation studies were performed to determine how changes in mesh density, mesh uniformity, fluid viscosity, and failure strain influence the test-analysis correlation.

  12. An investigation on impacts of scheduling configurations on Mississippi biology subject area testing

    NASA Astrophysics Data System (ADS)

    Marchette, Frances Lenora

    The purpose of this mixed modal study was to compare the results of Biology Subject Area mean scores of students on a 4 x 4 block schedule, A/B block schedule, and traditional year-long schedule for 1A to 5A size schools. This study also reviewed the data to determine if minority or gender issues might influence the test results. Interviews with administrators and teachers were conducted about the type of schedule configuration they use and the influence that the schedule has on student academic performance on the Biology Subject Area Test. Additionally, this research further explored whether schedule configurations allow sufficient time for students to construct knowledge. This study is important to schools, teachers, and administrators because it can assist them in considering the impacts that different types of class schedules have on student performance and if ethnic or gender issues are influencing testing results. This study used the causal-comparative method for the quantitative portion of the study and constant comparative method for the qualitative portion to explore the relationship of school schedules on student academic achievement on the Mississippi Biology Subject Area Test. The aggregate means of selected student scores indicate that the Mississippi Biology Subject Area Test as a measure of student performance reveals no significant difference on student achievement for the three school schedule configurations. The data were adjusted for initial differences of gender, minority, and school size on the three schedule configurations. The results suggest that schools may employ various schedule configurations and expect student performance on the Mississippi Biology Subject Area Test to be unaffected. However, many areas of concern were identified in the interviews that might impact on school learning environments. These concerns relate to effective classroom management, the active involvement of students in learning, the adequacy of teacher education programs and the stress of testing on everyone involved in high-stakes testing.

  13. Risk assessment test for lead bioaccessibility to waterfowl in mine-impacted soils

    USGS Publications Warehouse

    Furman, O.; Strawn, D.G.; Heinz, G.H.; Williams, B.

    2006-01-01

    Due to variations in soil physicochemical properties, species physiology, and contaminant speciation, Pb toxicity is difficult to evaluate without conducting in vivo dose-response studies. Such tests, however, are expensive and time consuming, making them impractical to use in assessment and management of contaminated environments. One possible alternative is to develop a physiologically based extraction test (PBET) that can be used to measure relative bioaccessibility. We developed and correlated a PBET designed to measure the bioaccessibility of Pb to waterfowl (W-PBET) in mine-impacted soils located in the Coeur d'Alene River Basin, Idaho. The W-PBET was also used to evaluate the impact of P amendments on Pb bioavailability. The W-PBET results were correlated to waterfowl-tissue Pb levels from a mallard duck [Anas platyrhynchos (L.)] feeding study. The W-PBET Pb concentrations were significantly less in the P-amended soils than in the unamended soils. Results from this study show that the W-PBET can be used to assess relative changes in Pb bioaccessibility to waterfowl in these mine-impacted soils, and therefore will be a valuable test to help manage and remediate contaminated soils.

  14. Capabilities of NASA/Marshall Space Flight Center's Impact Testing Facility

    NASA Technical Reports Server (NTRS)

    Hovater, Mary; Hubbs, Whitney; Finchum, Andy; Evans, Steve; Nehls, Mary

    2006-01-01

    The Impact Testing Facility (ITF) serves as an important installation for materials science at Marshall Space Flight Center (MSFC). With an array of air, powder, and two-stage light gas guns, a variety of projectile and target types and sizes can be accommodated. The ITF allows for simulation of impactors from rain to micrometeoroids and orbital debris on materials being investigated for space, atmospheric, and ground use. Expendable, relatively simple launch assemblies are used to obtain well-documented results for impact conditions comparable to those from ballistic and rocket sled ranges at considerably lower cost. In addition, for applications requiring study of impacts at speeds in excess of those attainable by gun launches, hydrocode simulations, validated by test data, can be used to extend the velocity range. In addition to serving various NASA directorates, the ITF has performed testing on behalf of the European and Russian space agencies, as well as the Department of Defense, and academic institutions. The m s contributions not only enable safer space flight for NASA s astronauts, but can help design materials and structures to protect soldiers and civilians on Earth, through advances in body armor, aircraft survivability, and a variety of other applications.

  15. Evaluation of synthetic composite tibias for fracture testing using impact loads.

    PubMed

    Quenneville, C E; Greeley, G S; Dunning, C E

    2010-10-01

    Composite synthetic bones are a commercially available substitute for cadaveric specimens, and they have previously been validated to replicate natural bone under quasistatic, non-destructive testing. Synthetic tibias could be used to analyse injury risk to the lower leg during impact events, but their failure mode must be validated by way of comparative tests to human bone. Synthetic tibias were instrumented with strain gauges and subjected to axial impact loading. Two different projectile masses were used for the tests, and the effects of force, momentum, and energy on failure were compared with previous cadaveric data. The composite tibias failed at forces between 37-45 per cent of those from cadavers, and failed via cortical delamination in combination with fracture. A Weibull analysis generated a survivability curve based on axial force at failure, and was shown to be lower than previous cadaveric curves. Failure was dependent on both the momentum and energy applied. Strain distributions through the synthetic tibias were significantly different from those of cadavers. The convex distal articular surface of the synthetic bones may partially account for the lower fracture tolerance. As a result of the many differences in response, these synthetic tibias are not recommended for use in impact fracture studies. PMID:21138237

  16. Quantifying the impact of future Sandage-Loeb test data on dark energy constraints

    E-print Network

    Jia-Jia Geng; Jing-Fei Zhang; Xin Zhang

    2014-07-03

    The Sandage-Loeb (SL) test is a unique method to probe dark energy in the "redshift desert" of $2\\lesssim z\\lesssim 5$, and thus it provides an important supplement to the other dark energy probes. Therefore, it is of great importance to quantify how the future SL test data impact on the dark energy constraints. To avoid the potential inconsistency in data, we use the best-fitting model based on the other geometric measurements as the fiducial model to produce 30 mock SL test data. The 10-yr, 20-yr, and 30-yr observations of SL test are analyzed and compared in detail. We show that compared to the current combined data of type Ia supernovae, baryon acoustic oscillation, cosmic microwave background, and Hubble constant, the 30-yr observation of SL test could improve the constraint on $\\Omega_m$ by about $80%$ and the constraint on $w$ by about $25%$. Furthermore, the SL test can also improve the measurement of the possible direct interaction between dark energy and dark matter. We show that the SL test 30-yr data could improve the constraint on $\\gamma$ by about $30%$ and $10%$ for the $Q=\\gamma H\\rho_c$ and $Q=\\gamma H\\rho_{de}$ models, respectively.

  17. A discussion of the impact of US chemical regulation legislation on the field of toxicity testing.

    PubMed

    Sullivan, Kristie; Beck, Nancy; Sandusky, Chad; Willett, Catherine

    2011-09-01

    Proposals for revising the principal United States law governing industrial chemicals, the Toxic Substances Control Act, have been under consideration in the US Congress for the past several years, and some version of such legislation may be passed in the near future. Concurrently, a desire to move away from current testing methods for ethical, scientific, and practical reasons has led to multi-million dollar investments in in vitro and computational toxicology methods and programs. Legislative language has the potential to endorse this transition and facilitate its fruition, or conversely enshrine in vivo testing methods for the foreseeable future. New legislation also has the potential to substantially increase the numbers of animals used in toxicity tests in the near term. However, there are a number of policies that, used effectively, can reduce the overall number of animals used in new toxicity tests. We present recent legislative proposals in the context of current testing programs and discuss their potential impacts on animal use, test method innovation, and achievement of desired legislative objectives. Discussions like these are essential to judiciously select policies that reduce the use of animals in toxicity testing and protect human health and the environment. PMID:21624455

  18. Pressure scaled water impact test of a 12.5 inch diameter model of the Space Shuttle solid rocket booster

    NASA Technical Reports Server (NTRS)

    1982-01-01

    A total of 59 tail first drops were made. Model entry conditions simulated full scale vertical velocities of approximately 75 to 110 ft/sec with horizontal velocities up to 45 ft/sec and impact angles to + or - 10 deg. These tests were conducted at scaled atmospheric pressures (1.26 psia or 65 mm.Hg). The model, test program, test facility, test equipment, instrumentation system, data reduction procedures, and test results are described.

  19. Scheduling scaffolding: the extent and arrangement of assistance during training impacts test performance.

    PubMed

    Tullis, Jonathan G; Goldstone, Robert L; Hanson, Andrew J

    2015-01-01

    Various kinds of assistance, including prompts, worked examples, direct instruction, and modeling, are widely provided to learners across educational and training programs. Yet, the effectiveness of assistance during training on long-term learning is widely debated. The authors examined how the extent and schedule of assistance during training on a novel mouse movement task impacted unassisted test performance. Learners received different schedules of assistance during training, including constant assistance, no assistance, probabilistic assistance, alternating assistance, and faded assistance. Constant assistance led to better performance during training than no assistance. However, constant assistance during training resulted in the worst unassisted test performance. Faded assistance during training resulted in the best test performance. This suggests that fading may allow learners to create an internal model of the assistance without depending on the assistance in a manner that impedes successful transfer to unassisted circumstances. PMID:25760764

  20. Force reconstruction for impact tests of an energy-absorbing nose

    SciTech Connect

    Bateman, V.I.; Garne, T.G.; McCall, D.M.

    1990-01-01

    Delivery of a bomb into hard targets at speeds of up to 120 fps required the design of an energy-absorbing nose. The purpose of the nose is to decelerate the projectile and, by absorbing the kinetic energy with deformation, protect the projectile's internal components from high-level (shock) decelerations. A structural simulation of the projectile was designed to test the dynamic deformation characteristics of the energy-absorbing nose. The simulated projectile was instrumented with eight accelerometers mounted with a shock isolation technique. The dynamic force as a function of nose deformation was the desired result from the impact tests because it provides the designer with a performance criterion for the nose design. The dynamic force was obtained by combining the accelerations using the Sum of Weighted Accelerations Technique (SWAT). Results from two field tests are presented. 12 refs., 8 figs.

  1. Crushable structure performance determined from reconstructed dynamic forces during impact tests

    SciTech Connect

    Bateman, V.I.

    1995-01-01

    A force reconstruction technique has been used to assess the dynamic performance of a crushable structure (a bomb nose) in both the axial (90{degrees}) and slapdown (30{degrees}) impact conditions. The dynamic force characteristics for the nose design, determined from these test results, have been used to write a dynamic force specification for a new nose design that will replace the old nose. The dynamic forces are reconstructed from measured acceleration responses with the Sum of Weighted Accelerations Technique (SWAT) developed at Sandia National Laboratories. Axial characterizations for the old nose are presented from tests at two SNL facilities: a rocket rail launcher facility and an 18-Inch horizontal actuator facility. The characterizations for the old nose are compared to the characterizations for two new nose designs. Slapdown characterizations for the old nose are presented. Incorporation of the test results into a dynamic force specification is discussed.

  2. Testing, Modeling and System Impact of Metabolic Heat Regenerated Temperature Swing Adsorption

    NASA Technical Reports Server (NTRS)

    Lacomini, Christine S.; Powers, Aaron; Lewis, Matthew; Linrud, Christopher; Waguespack, Glenn; Conger, Bruce; Paul, Heather L.

    2008-01-01

    Metabolic heat regenerated temperature swing adsorption (MTSA) technology is being developed for removal and rejection of carbon dioxide (CO2) and heat from a portable life support system (PLSS) to the Martian environment. Previously, hardware was built and tested to demonstrate using heat from simulated, dry ventilation loop gas to affect the temperature swing required to regenerate an adsorbent used for CO2 removal. New testing has been performed using a moist, simulated ventilation loop gas to demonstrate the effects of water condensing and freezing in the heat exchanger during adsorbent regeneration. In addition, thermal models of the adsorbent during regeneration were modified and calibrated with test data to capture the effect of the CO2 heat of desorption. Finally, MTSA impact on PLSS design was evaluated by performing thermal balances assuming a specific PLSS architecture. Results using NASA s Extravehicular Activity System Sizing Analysis Tool (EVAS_SAT), a PLSS system evaluation tool, are presented.

  3. Assessing the Impact of Testing Aids on Post-Secondary Student Performance: A Meta-Analytic Investigation

    ERIC Educational Resources Information Center

    Larwin, Karen H.; Gorman, Jennifer; Larwin, David A.

    2013-01-01

    Testing aids, including student-prepared testing aids (a.k.a., cheat sheets or crib notes) and open-textbook exams, are common practice in post-secondary assessment. There is a considerable amount of published research that discusses and investigates the impact of these testing aids. However, the findings of this research are contradictory and…

  4. The role of IS architecture planning in enhancing IS outsourcing's impact on IS performance : Its antecedents and an empirical test

    Microsoft Academic Search

    Zhengzhong Shi

    2010-01-01

    Purpose – The purpose of this paper is to develop a conceptual model on the role that information systems (IS) architecture planning plays in enhancing IS outsourcing's impact on IS performance and to empirically test the model. Design\\/methodology\\/approach – Survey data were gathered and structural equation modeling technique is used to test hypotheses. Findings – The empirical test clearly demonstrates

  5. Fibre optic sensors for high speed hypervelocity impact studies and low velocity drop tests

    NASA Astrophysics Data System (ADS)

    Jackson, D. A.; Cole, M. J.; Burchell, M. J.; Webb, D. J.

    2011-05-01

    The initial aim of this project was to develop a non-contact fibre optic based displacement sensor to operate in the harsh environment of a 'Light Gas Gun' (LGG), which can 'fire' small particles at velocities ranging from 1-8.4 km/s. The LGG is used extensively for research in aerospace to analyze the effects of high speed impacts on materials. Ideally the measurement should be made close to the centre of the impact to minimise corruption of the data from edge effects and survive the impact. A further requirement is that it should operate at a stand-off distance of ~ 8cm. For these reasons we chose to develop a pseudo con-focal intensity sensor, which demonstrated resolution comparable with conventional PVDF sensors combined with high survivability and low cost. A second sensor was developed based on 'Fibre Bragg Gratings' (FBG) which although requiring contact with the target the low weight and very small contact area had minimal effect on the dynamics of the target. The FBG was mounted either on the surface of the target or tangentially between a fixed location. The output signals from the FBG were interrogated in time by a new method. Measurements were made on composite and aluminium plates in the LGG and on low speed drop tests. The particle momentum for the drop tests was chosen to be similar to that of the particles used in the LGG.

  6. Laminated Windshield Breakage Modelling in the Context of Headform Impact Homologation Tests

    NASA Astrophysics Data System (ADS)

    Kosi?ski, P.; Osi?ski, J.

    2015-02-01

    The purpose of modelling a laminated windshield using the FEM is to provide a critical look on the way the adult headform impact tests are conducted in the process of motor vehicle certification. The main aim of the study is to modify the design of a laminated windshield in the context of a vehicle collision with vulnerable road users. The initial phase of the work was to develop a model of the adult headform impactor. The validation consisted in conducting a series of FEM analyses of the impactor certification testing according to the Regulation (EC) 631/2009. Next, the impact of the headform model on a windshield was analysed. The FEM model of laminated glass is composed of two outer layers of glass and an inner layer of polyvinyl butyral. FEM analyses of the impaction were performed at five points of the windshield characterised by various dynamic responses of the impactor and various patterns of glass cracking. In modelling the layers of glass, the Abaqus environment "brittle cracking" model was used. The following material models of PVB resin were considered: elastic, elastic-plastic, hyperelastic, and low-density foam. Furthermore, the influence of the mesh type on the process of glass cracking in a laminated windshield was analysed.

  7. Impact of gene patents on diagnostic testing: a new patent landscaping method applied to spinocerebellar ataxia

    PubMed Central

    Berthels, Nele; Matthijs, Gert; Van Overwalle, Geertrui

    2011-01-01

    Recent reports in Europe and the United States raise concern about the potential negative impact of gene patents on the freedom to operate of diagnosticians and on the access of patients to genetic diagnostic services. Patents, historically seen as legal instruments to trigger innovation, could cause undesired side effects in the public health domain. Clear empirical evidence on the alleged hindering effect of gene patents is still scarce. We therefore developed a patent categorization method to determine which gene patents could indeed be problematic. The method is applied to patents relevant for genetic testing of spinocerebellar ataxia (SCA). The SCA test is probably the most widely used DNA test in (adult) neurology, as well as one of the most challenging due to the heterogeneity of the disease. Typically tested as a gene panel covering the five common SCA subtypes, we show that the patenting of SCA genes and testing methods and the associated licensing conditions could have far-reaching consequences on legitimate access to this gene panel. Moreover, with genetic testing being increasingly standardized, simply ignoring patents is unlikely to hold out indefinitely. This paper aims to differentiate among so-called ‘gene patents' by lifting out the truly problematic ones. In doing so, awareness is raised among all stakeholders in the genetic diagnostics field who are not necessarily familiar with the ins and outs of patenting and licensing. PMID:21811306

  8. Characterization of impact damage resistance of CF/PEEK and CF/toughened epoxy laminates under low and high velocity impact tests

    SciTech Connect

    Morita, Hideo [Ishikawajima-Harima Heavy Industries Co., Ltd., Yokohama (Japan). Research Inst.; Adachi, Tadaharu; Tateishi, Yasuhiro; Matsumoto, Hiroyuki [Tokyo Inst. of Technology (Japan). Dept. of Mechanical Engineering and Science

    1995-12-31

    In order to use composite materials in aeronautical turbo engines, their resistance to impact damage must be understood. In this work the subperforation flat-wise impact resistance of three kinds of high resistance material systems were evaluated under low and high velocity impact tests. Tested systems were AS4/PEEK (APC-2/AS4, ICI-Fiberite), AS4/PEEK+IL, which consists of APC-2 prepreg and PEEK film inserted between layers as an interleave, and toughened epoxy system T800/{number_sign}3900 (Toray). To investigate the effects of stacking sequence on resistance, three lay-ups -- (0/+30/0/{minus}30)s, (0/+60/0/{minus}60)s, and (0/+45/90/{minus}45)s -- were tested. A drop weight system was used for the low velocity tests, where the velocity ranged from 1.5 to 3.1 m/s. An air gun system was used for the high velocity tests, where the velocity range was between 50 and 100 m/s. The relation between damage area (DA) and impact energy (IE) was linear, and the ratio of the DA/IE quantified the impact resistance of each specimen. The value of DA/IE for the high velocity tests was larger than the value for low velocity tests. To estimate the lay-up effect, a stacking parameter {beta}, which indicates the difference of the inplane stiffness between the adjacent laminae, was proposed. A proportional relation between the DA/IE and the {beta} was obtained. The value of (DA/IE)/{beta}, which was independent of stacking sequence, indicated the impact resistance of the tested material systems for both velocity levels. The ratio of (DA/IE)/{beta} for the high velocity to the value for the low velocity changed with material systems.

  9. JOURNAL DE PHYSIQUEIV ColloqueC7, suppldmentau Journal de Physique 111,Volume 3, novembre 1993

    E-print Network

    Boyer, Edmond

    at drop weight tests. The wide range of transition temperatures in this diagram clearly shows that wery. Examples of Charpy V-notch impact curves of absorbed energy versus testing temper- ature for investigated, Cestaielezarjev8, 64270Jesenice, Slovenia The conventional test methods combined with non-standard measuring

  10. A Gas-Actuated Projectile Launcher for High-Energy Impact Testing of Structures

    NASA Technical Reports Server (NTRS)

    Ambur, Damodar R.; Jaunky, Navin; Lawson, Robin E.; Knight, Norman F., Jr.; Lyle, Karen H.

    1999-01-01

    A gas-act,uated penetration device has been developed for high-energy impact testing of structures. The high-energy impact. t,estiiig is for experimental simulation of uncontained engine failures. The non-linear transient finite element, code LS-DYNA3D has been used in the numerical simula.tions of a titanium rectangular blade with a.n aluminum target, plate. Threshold velocities for different combinations of pitch and yaw angles of the impactor were obtained for the impactor-target, t8est configuration in the numerica.1 simulations. Complet,e penet,ration of the target plate was also simulat,ed numerically. Finally, limited comparison of analytical and experimental results is presented for complete penetration of the target by the impactor.

  11. Verification of maximum impact force for interim storage cask for the Fast Flux Testing Facility

    SciTech Connect

    Chen, W.W. [Westinghouse Hanford Co., Richland, WA (United States); Chang, S.J. [Oak Ridge National Lab., TN (United States)

    1996-06-01

    The objective of this paper is to perform an impact analysis of the Interim Storage Cask (ISC) of the Fast Flux Test Facility (FFTF) for a 4-ft end drop. The ISC is a concrete cask used to store spent nuclear fuels. The analysis is to justify the impact force calculated by General Atomics (General Atomics, 1994) using the ILMOD computer code. ILMOD determines the maximum force developed by the concrete crushing which occurs when the drop energy has been absorbed. The maximum force, multiplied by the dynamic load factor (DLF), was used to determine the maximum g-level on the cask during a 4-ft end drop accident onto the heavily reinforced FFTF Reactor Service Building`s concrete surface. For the analysis, this surface was assumed to be unyielding and the cask absorbed all the drop energy. This conservative assumption simplified the modeling used to qualify the cask`s structural integrity for this accident condition.

  12. Model Investigation of Technique for Full Scale Landing Impact Tests at Simulated Lunar Gravity

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Model Investigation of Technique for Full Scale Landing Impact Tests at Simulated Lunar Gravity. An investigation of a 1/6-scale dynamic model has been made to develop and evaluate a technique for conducting full-scale landing-impact tests at simulated lunar gravity. Landings were made at touchdown pitch attitudes of -15 degrees, 0 degrees, and 15 degrees. All landings were made with two gear pads forward and at a roll attitude of 0 degrees. Both roll and yaw attitudes were constrained. Vertical landing speed was varied from 5 to 15 feet per second (1.5 to 4.6 m/s) and horizontal speed was varied from 0 to 10 feet per second (0 to 3.0 m/s). Most of the landings were made at a vertical and horizontal speed of 10 feet per second or 3.0 m/s (45 degree flight-path angle) while pitch attitude and surface characteristics, friction and topography, were varied. These parameters were investigated with the free-body earth-gravity and the simulated lunar-gravity test techniques. The landings were made at a model mass corresponding to a full-scale lunar weight (force due to gravity) of 1,440 pounds (6.41 kN) or an earth weight of 8,640 pounds (38.4 kN). [Entire movie available on DVD from CASI as Doc ID 20070030977. Contact help@sti.nasa.gov

  13. Damage Detection and Impact Testing on Laminated and Sandwich Composite Panels

    NASA Technical Reports Server (NTRS)

    Hughes, Derke R.; Craft, William J.; Schulz, Mark J.; Naser, Ahmad S.; Martin, William N.

    1998-01-01

    This research investigates health monitoring of sandwich shell composites to determine if the Transmittance Functions (TF) are effective in determining the present of damage. The health monitoring test was conducted on the sandwich plates before and after low velocity impacts using the health monitoring technique given in TFs are a NDE (Nondestructive Evaluation) technique that utilizes the ratios of cross-spectrums to auto-spectrums between two response points on the sandwich composites. The test for transmittance was conducted on the same density foam core throughout the experiment. The test specimens were 17.8 cm by 25.4 cm in dimension. The external sheets (face sheets) were created from graphite/epoxy laminate with dimension of 1.58 mm thick. The polymethacrylide (Rohacell) foam core was 12.7 mm thick. These samples experienced a transformation in the TF that was considered the low velocity impact damage. The low velocity damage was observed in the TFs for the sandwich composites.

  14. LX-04 Violence Measurments: Steven Tests Impacted By Projectiles Shot From A Howitzer Gun

    NASA Astrophysics Data System (ADS)

    Chidester, Steven K.

    2005-07-01

    Characterization of the reaction violence of LX-04 explosive (85% HMX and 15% Viton by weight) was obtained from Steven Impact Tests performed above the reaction initiation threshold. A 155 mm Howitzer propellant driven gas gun was used to accelerate the Steven Test projectiles in the range of approximately 150-300 m/s to react (ignite) the LX-04 explosive. Blast overpressure gauges, acoustic microphones, and high-speed photography characterized the level of high explosive reaction violence. A detonation in this velocity range was not observed and when comparing these results (and the Susan test results) with that of other HMX based explosives, LX-04 has a more gradual reaction violence slope as the impact velocity increases. The high binder content (15%) of the LX-04 explosive is believed to be the key factor to the lower level of violence. This work was performed under the auspices of the U. S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.

  15. High-Rate Material Modeling and Validation Using the Taylor Cylinder Impact Test

    SciTech Connect

    Maudlin, P.J.; Gray, G.T. III; Cady, C.M.; Kaschner, G.C.

    1998-10-21

    Taylor Cylinder impact testing is used to validate anisotropic elastoplastic constitutive modeling by comparing polycrystal simulated yield surface shapes (topography) to measured shapes from post-test Taylor impact specimens and quasistatic compression specimens. Measured yield surface shapes are extracted from the experimental post-test geometries using classical r-value definitions modified for arbitrary stress state and specimen orientation. Rolled tantalum (body-centered-cubic metal) plate and clock-rolled zirconium (hexagonal-close-packed metal) plate are both investigated. The results indicate that an assumption of topography invariance with respect to strain-rate is justifiable for tantalum. However, a strong sensitivity of topography with respect to strain-rate for zirconium was observed, implying that some accounting for a deformation mechanism rate-dependence associated with lower-symmetry materials should be included in the constitutive modeling. Discussion of the importance of this topography rate-dependence and texture evolution in formulating constitutive models appropriate for FEM applications is provided.

  16. Hybrid III Lower Leg Injury Assessment Reference Curves Under Axial Impacts Using Matched-Pair Tests.

    PubMed

    Yoganandan, Narayan; Pintar, Frank; Banerjee, Anjishnu; Schlick, Michael; Chirvi, Sajal; Uppal, Hermeeth; Merkle, Andrew; Voo, Liming; Kleinberg, Michael

    2015-01-01

    The objective of the present study was to derive injury probability curves applicable to the Hybrid III dummy (also termed the Anthropomorphic Test Device, ATD) lower leg under axial impacts for military applications. A matched-pair approach was used. Axial impacts were delivered to below knee foot-ankle complex preparations of the lower leg of the ATD using pendulum and custom vertical accelerator devices. Military boot was used in some tests. Post mortem human surrogate (PMHS) preparations were used as matched-pair tests for injury outcomes. The alignment was such that the foot-ankle complex was orthogonal to the leg (below knee tibia-fibula complex), termed as the normal 90-90 posture. Injury outcomes from the biological surrogate focused on calcaneus and or distal tibia fractures with or without the involvement of articular surfaces. Peak lower tibia load cell forces were obtained from matched-pair dummy tests. Injury and force data were paired, censoring was assigned based on injury outcomes and survival analysis was done using the Weibull distribution to derive dummy-based probability curves. Mean peak forces were extracted at 5, 10, 20 and 50% probability levels. Normalized confidence interval sizes (NCIS) at ± 95% level were computed to determine the tightness-of-fit of the confidence bands. The NCIS data ranged from 0.34 to 0.78 and a peak force of 8.2 kN was associated at the ten percent injury probability level. Other data and curves are given in the body of the paper. The present Injury Assessment Reference Curves and Values (IARC and IARV) may be used in future tests for advancing safety in military environments. These survival analysis processes and IARC and IARV data may also be used in other applications. PMID:25996722

  17. A Study of the Economic Impact of Water Impoundment Through Validity Testing of a Comparitive-Projection Model 

    E-print Network

    Pearson, J. E.; Heideman, K. E.

    1969-01-01

    An established economic simulation model for reservoir development was applied to ten reservoir projects throughout Texas. The model as a predictor of economic impact was given a difficult test because of the diversity of ...

  18. A Study of the Economic Impact of Water Impoundment Through Validity Testing of a Comparitive-Projection Model

    E-print Network

    Pearson, J. E.; Heideman, K. E.

    An established economic simulation model for reservoir development was applied to ten reservoir projects throughout Texas. The model as a predictor of economic impact was given a difficult test because of the diversity of geographic, economic...

  19. The impact of ethical beliefs on decisions about prenatal screening tests: searching for justification.

    PubMed

    García, Elisa; Timmermans, Danielle R M; van Leeuwen, Evert

    2008-02-01

    Prenatal screening for Down's syndrome and other chromosomal anomalies has become common obstetrical practice. The purpose of this intervention is to provide women with the information needed to make informed reproductive choices. It is assumed that the ethical beliefs of parents play an important role in decision-making about whether to undergo testing, but little is known about their precise significance. More insight into how women conceptualize their choice of using prenatal screening tests may clarify the impact of personal ethical beliefs. With this aim, we conducted qualitative research consisting of semi-structured interviews with 59 women in the Netherlands who were offered a prenatal screening test. The analysis showed that the ethical views between acceptors and decliners showed similar diversity. In contrast with the currently accepted view, we conclude that ethical beliefs are one of the factors implicated in the decision. Women decide about prenatal testing by balancing the information provided by the test against the risks of further investigation, the emotional burden of a disabled child on their well-being and life perspective, as well as on those of family members. Normative moral principles are introduced once the choice is made, namely as factors in justifying and supporting the decision. PMID:17996350

  20. Closure Report for Corrective Action Unit 107: Low Impact Soil Sites, Nevada Test Site, Nevada

    SciTech Connect

    NSTec Environmental Restoration

    2009-06-01

    Corrective Action Unit (CAU) 107 is identified in the Federal Facility Agreement and Consent Order (FFACO) as 'Low Impact Soil Sites' and consists of the following 15 Corrective Action Sites (CASs), located in Areas 1, 2, 3, 4, 5, 9, 10, and 18 of the Nevada Test Site: CAS 01-23-02, Atmospheric Test Site - High Alt; CAS 02-23-02, Contaminated Areas (2); CAS 02-23-03, Contaminated Berm; CAS 02-23-10, Gourd-Amber Contamination Area; CAS 02-23-11, Sappho Contamination Area; CAS 02-23-12, Scuttle Contamination Area; CAS 03-23-24, Seaweed B Contamination Area; CAS 03-23-27, Adze Contamination Area; CAS 03-23-28, Manzanas Contamination Area; CAS 03-23-29, Truchas-Chamisal Contamination Area; CAS 04-23-02, Atmospheric Test Site T4-a; CAS 05-23-06, Atmospheric Test Site; CAS 09-23-06, Mound of Contaminated Soil; CAS 10-23-04, Atmospheric Test Site M-10; and CAS 18-23-02, U-18d Crater (Sulky). Closure activities were conducted from February through April 2009 according to the FFACO (1996; as amended February 2008) and Revision 1 of the Streamlined Approach for Environmental Restoration Plan for CAU 107 (U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, 2009). The corrective action alternatives included No Further Action and Closure in Place with Administrative Controls. Closure activities are summarized.

  1. Charpy impact test results for unirradiated tantalum, tungsten and molybdenum alloys

    SciTech Connect

    Gelles, D.S.; Cannon, N.S.; Hu, W.L.; Hack, J.

    1987-12-01

    Charpy impact tests have been performed on 1/2 sized CVN specimens of T-111, a tantalum based alloy, and two experimental alloys with rhenium additions for improved low temperature ductility, W-26Re and Mo-13Re. The tantalum alloy was found to have a ductile to brittle transition below /minus/175/degree/C whereas the rhenium containing alloys both had a DBTT above 250/degree/C. The high DBTT found for rhenium containing alloys appears to be an inherent property of the alloy class. 9 refs., 8 figs., 2 tabs.

  2. A novel impact three-point bend test method for determining dynamic fracture-initiation toughness

    Microsoft Academic Search

    T. Yokoyama; K. Kishida

    1989-01-01

    A novel impact three-point bend test method has been developed for determining the dynamic fracture-initiation toughness,K\\u000a Id, over the range of loading rates\\u000a $$10^5 MPa\\\\sqrt m \\/s \\\\leqslant K_I \\\\leqslant 10^5 MPa\\\\sqrt m \\/s$$\\u000a . The split-Hopkinson pressure-bar technique is used to measure dynamic loads applied to a bend specimen with a fatigue precrack.\\u000a The stress-intensity-factor histories for the bend

  3. One-Year Test-Retest Reliability of the Online Version of ImPACT in High School Athletes

    Microsoft Academic Search

    R. J. Elbin; Philip Schatz; Tracey Covassin

    2011-01-01

    Background: The ImPACT (Immediate Post-Concussion Assessment and Cognitive Testing) neurocognitive testing battery is a popular assessment tool used for concussion management. The stability of the baseline neurocognitive assessment is important for accurate comparisons between postconcussion and baseline neurocognitive performance. Psychometric properties of the recently released online version of ImPACT have yet to be established; therefore, research evaluating the reliability of

  4. Effect of thermal-softening in rod impact test for the determination of dynamic material properties of polycarbonate

    Microsoft Academic Search

    Jeongmin Lee; Oakkey Min

    1995-01-01

    A theory was developed to investigate the effect of thermal-softening in rod impact test for the determination of the dynamic\\u000a material properties of Polycarbonate, on the basis of one-dimensional shock wave propagation phenomena. High velocity rod\\u000a impact test was performed with flat-ended cylindrical rod specimens. From the geometrical measurements of deformed rod, dynamic\\u000a material properties were determined by both previous

  5. Calibration of an item pool for assessing the burden of headaches: An application of item response theory to the Headache Impact Test (HIT™)

    Microsoft Academic Search

    Jakob B. Bjorner; Mark Kosinski; John E. Ware Jr

    2003-01-01

    Background: Measurement of headache impact is important in clinical trials, case detection, and the clinical monitoring of patients. Computerized adaptive testing (CAT) of headache impact has potential advantages over traditional fixed-length tests in terms of precision, relevance, real-time quality control and flexibility. Objective: To develop an item pool that can be used for a computerized adaptive test of headache impact.

  6. Evaluation of effect of hydrogen on toughness of Zircaloy-2 by instrumented drop weight impact testing

    NASA Astrophysics Data System (ADS)

    Viswanathan, U. K.; Singh, R. N.; Basak, C. B.; Anantharaman, S.; Sahoo, K. C.

    2006-05-01

    Hydride-assisted degradation in fracture toughness of Zircaloy-2 was evaluated by carrying out instrumented drop-weight tests on curved Charpy specimens fabricated from virgin pressure tube. Samples were charged to 60 ppm and 225 ppm hydrogen. Ductile-to-brittle-transition behaviour was exhibited by as-received and hydrided samples. The onset of ductile-to-brittle-transition was at about 130 °C for hydrided samples, irrespective of their hydrogen content. Dynamic fracture toughness ( KID) was estimated based on linear elastic fracture mechanics (LEFM) approach. For fractures occurring after general yielding, the fracture toughness was derived based on equivalent energy criterion. Results are supplemented with fractography. This simple procedure of impact testing appears to be promising for monitoring service-induced degradation in fracture toughness of pressure tubes.

  7. Gas Gun Impact Testing of PZT 95/5, Part 1: Unpoled State

    SciTech Connect

    FURNISH,MICHAEL D.; SETCHELL,ROBERT E.; CHHABILDAS,LALIT C.; MONTGOMERY,STEPHEN T.

    2000-01-01

    In the present study, 10 impact tests were conducted on unpoled PZT 95/5, with 9% porosity and 2 at% Nb doping. These tests were instrumented to obtain time-resolved loading, unloading and span signatures. As well, PVDF gauges allowed shock timing to be established explicitly. The ferroelectric/antiferroelectric phases transition was manifested as a ramp to 0.4 GPa. The onset of crushup produced the most visible signature: a clear wave separation at 2.2 GPa followed by a highly dispersive wave. The end states also reflected crushup, and are consistent with earlier data and with related poled experiments. A span strength value of 0.17 GPa was measured for a shock stress of 0.5 GPa, this decreased to a very small value (no visible pullback signature) for a shock strength of 1.85 GPa.

  8. Impact of rapid screening tests on acquisition of meticillin resistant Staphylococcus aureus: cluster randomised crossover trial

    PubMed Central

    2008-01-01

    Objective To determine whether introducing a rapid test for meticillin resistant Staphylococcus aureus (MRSA) screening leads to a reduction in MRSA acquisition on hospital general wards. Design Cluster randomised crossover trial. Setting Medical, surgical, elderly care, and oncology wards of a London teaching hospital on two sites. Main outcome measure MRSA acquisition rate (proportion of patients negative for MRSA who became MRSA positive). Participants All patients admitted to the study wards who were MRSA negative on admission and screened for MRSA on discharge. Intervention Rapid polymerase chain reaction based screening test for MRSA compared with conventional culture. Results Of 9608 patients admitted to study wards, 8374 met entry criteria and 6888 had full data (82.3%); 3335 in the control arm and 3553 in the rapid test arm. The overall MRSA carriage rate on admission was 6.7%. Rapid tests led to a reduction in median reporting time from admission, from 46 to 22 hours (P<0.001). Rapid testing also reduced the number of inappropriate pre-emptive isolation days between the control and intervention arms (399 v 277, P<0.001). This was not seen in other measurements of resource use. MRSA was acquired by 108 (3.2%) patients in the control arm and 99 (2.8%) in the intervention arm. When predefined confounding factors were taken into account the adjusted odds ratio was 0.91 (95% confidence interval 0.61 to 1.234). Rates of MRSA transmission, wound infection, and bacteraemia were not statistically different between the two arms. Conclusion A rapid test for MRSA led to the quick receipt of results and had an impact on bed usage. No evidence was found of a significant reduction in MRSA acquisition and on these data it is unlikely that the increased costs of rapid tests can be justified compared with alternative control measures against MRSA. Trial registration Clinical controlled trials ISRCTN75590122. PMID:18417521

  9. Reproductive genetic testing from an international perspective: impact on women in underdeveloped countries.

    PubMed

    Penchaszadeh, Victor B

    1993-04-01

    The impact of reproductive genetic testing (preconceptional and prenatal screening for genetic diseases) on women in the third world must take into account the many aspects that characterize underdevelopment: poverty; little access to education; housing; adequate nutrition; health services, and other. In these countries women usually suffer from male domination in a number of aspects of their lives, including reproduction. Illiteracy is high, particularly among women. Infant mortality and fertility rates are high, and the primary causes of death are infectious diseases and malnutrition. Health services are poorly organized, and family planning and prenatal care programs are deficient. Although abortions are illegal, they outnumber live births 3:1. Maternal mortality is 10-100 times higher than in industrialized nations, and complications of illegal abortions are one of its main causes. This description applies to the majority of the population and contrasts with that of the small segment of well-to-do upper classes, who have access to education, housing and health services that include family planning, prenatal care and reproductive genetic testing. By and large, all main cities count with clinical genetic centers. The illegality of abortion, however, makes prenatal testing in the public sector a difficult task, while in the private sector quality control is an unheard concept and the patients frequently fall victims of the entrepreneurial and commercial goals of the providers. For the majority of the population, the impact of reproductive genetic testing is almost nil, simply because the services are not available.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:11653019

  10. Assessment of the TASER XREP blunt impact and penetration injury potential using cadaveric testing.

    PubMed

    Lucas, Scott R; McGowan, Joseph C; Lam, Tack C; Yamaguchi, Gary T; Carver, Matthew; Hinz, Andrew

    2013-01-01

    TASER International's extended range electronic projectile (XREP) is intended to be fired from a shotgun, impact a threat, and apply remote neuromuscular incapacitation. This study investigated the corresponding potential of blunt impact injury and penetration. Forty-three XREP rounds were deployed onto two male human cadaver torsos at impact velocities between 70.6 and 95.9 m/sec (232 and 315 ft/sec). In 42 of the 43 shots fired, the XREP did not penetrate the abdominal wall, resulting in superficial wounds only. On one shot, the XREP's nose section separated prematurely in flight, resulting in penetration. No bony fractures were observed with any of the shots. The viscous criterion (VC), blunt criterion (BC), and energy density (E/A) were calculated (all nonpenetrating tests, average ± 1 standard deviation: VC: 1.14 ± 0.94 m/sec, BC: 0.77 ± 0.15, E/A: 22.6 ± 4.15 J/cm(2)) and, despite the lack of injuries, were generally found to be greater than published tolerance values. PMID:23067043

  11. Safety Issues in the Nuclear Electric Propulsion Space Test Environmental Impact Statement

    NASA Astrophysics Data System (ADS)

    Glover, William A.

    1994-07-01

    The National Environmental Policy Act (NEPA), requires Federal agencies to prepare environmental impact statements (EIS) for actions which might have a significant impact on the human environment. Launching a nuclear reactor into Earth orbit is such an action. Although the normal operations of the space nuclear reactor may have a minimal effect on the human environment, launch accidents, criticality accidents, and inadvertent reentry of the reactor into the biosphere could have significant environmental impacts. Thus, an EIS must examine the proposed action and reasonable alternatives to allow the decdision makers to make better environmentally informed decisions. The issues related to reactor safety are of particular interest to both the public and to agency decision makers and, therefore, tend to be the most visible and controversial aspects of the EIS. The EIS also represents the major opportunity for direct public involvement in the decision-making process. This paper discusses the approach to nuclear reactor safety issues in the Nuclear Electric Propulsion Space Test EIS, which will examine the environmental issues related to the proposed launching of the Topaz II reactor.

  12. Energy absorption behavior of closed-cell aluminium foam under drop mass impact tests

    NASA Astrophysics Data System (ADS)

    Yang, Fujun; Ni, Siyuan; He, Xiaoyuan; He, Deping

    2008-11-01

    Quasi-static axial compression and drop mass impact tests were performed to study the energy absorption behaviour of the closed-cell aluminium foam. Digital image analysis was firstly used to characterize the surface's structure of individual cells and aggregates of cells. The cell structure characterizations performed using the best-fit ellipse equivalent diameter for the individual cells, which included measurement of the size distribution of cells, cell's aspect ratio and orientation. It shows that the statistical distribution of cells' size and cell's aspect ratio well follow Gauss distributions. The energy absorption behavior of the high porosities aluminium foam under static and drop weight impact compression were then conducted. High-speed imaging technique and temporal digital image correlation method were employed to evaluate the deformation and acceleration in the compression experiments. Using these approaches, the deformation and energy absorption mechanism of Al foam due to drop impact can be observed and better understood. The experimental results show that aluminium foams are quite close to a kind of isotropic structure and have high energy absorption capabilities.

  13. Design and testing of miniaturized plasma sensor for measuring hypervelocity impact plasmas.

    PubMed

    Goel, A; Tarantino, P M; Lauben, D S; Close, S

    2015-04-01

    An increasingly notable component of the space environment pertains to the impact of meteoroids and orbital debris on spacecraft and the resulting mechanical and electrical damages. Traveling at speeds of tens of km/s, when these particles, collectively referred to as hypervelocity particles, impact a satellite, they vaporize, ionize, and produce a radially expanding plasma that can generate electrically harmful radio frequency emission or serve as a trigger for electrostatic discharge. In order to measure the flux, composition, energy distribution, and temperature of ions and electrons in this plasma, a miniaturized plasma sensor has been developed for carrying out in-situ measurements in space. The sensor comprises an array of electrostatic analyzer wells split into 16 different channels, catering to different species and energy ranges in the plasma. We present results from numerical simulation based optimization of sensor geometry. A novel approach of fabricating the sensor using printed circuit boards is implemented. We also describe the test setup used for calibrating the sensor and show results demonstrating the energy band pass characteristics of the sensor. In addition to the hypervelocity impact plasmas, the plasma sensor developed can also be used to carry out measurements of ionospheric plasma, diagnostics of plasma propulsion systems, and in other space physics experiments. PMID:25933852

  14. Instrumented impact testing of an irradiated 20MnMoNi55 PVS weld material

    NASA Astrophysics Data System (ADS)

    Ghoneim, M. M.; Hammad, F. H.

    1992-01-01

    Instrumented impact tests were carried out on a 20MnMoNi55 pressure vessel steel (PVS) weld material before and after fast neutron irradiation to 2.5 × 10 19n/ cm2 at 160°C and to 3.5 × 10 19n/ cm2 and 7 × 10 19n/ cm2 at 290°C. The correlation between the fracture surface appearance and the load-time curve obtained from the tests was investigated. The impact energy was divided into fracture initiation energy and fracture propagation energy. Neutron irradiation decreased the ratio of the initiation energy to the total energy from 15% before irradiation to 10, 9.2, and 6.4% after exposure to 3.5 × 10 19n/ cm2 ( Tirr = 290° C), 7 × 10 19n/ cm2 ( Tirr = 290° C) and 2.5 × 10 19n/ cm2 ( Tirr = 160° C), respectively. The fracture initiation energy was used to establish a correlation with fracture toughness. This correlation can be used to estimate the fracture toughness of the steel after neutron irradiation.

  15. Internally damped, self-arresting vertical drop-weight impact test apparatus

    NASA Technical Reports Server (NTRS)

    Ambur, Damodar R. (Inventor); Prasad, Chunchu B. (Inventor); Waters, Jr., William A. (Inventor); Stockum, Robert W. (Inventor); Water, Manfred A. (Inventor)

    1995-01-01

    A vertical dropped-weight impact test machine has a dropped-weight barrel vertically supported on upper and lower support brackets. The dropped-weight barrel is chambered to receive a dropped-weight assembly having a latch pin at its upper end, a damping unit in the middle, and a tup at its lower end. The tup is adapted for gathering data during impact testing. The latch pin releasably engages a latch pin coupling assembly. The latch pin coupling assembly is attached to a winch via a halyard for raising and lowering the dropped-weight assembly. The lower end of the dropped-weight barrel is provided with a bounce-back arresting mechanism which is activated by the descending passage of the dropped-weight assembly. After striking the specimen, the dropped-weight assembly rebounds vertically and is caught by the bounce-back arresting mechanism. The damping unit of the dropped-weight assembly serves to dissipate energy from the rebounding dropped-weight assembly and prevents the dropped-weight assembly from rebounding from the self-arresting mechanism.

  16. Internally damped, self-arresting vertical drop-weight impact test apparatus

    NASA Technical Reports Server (NTRS)

    Ambur, Damodar R. (Inventor); Prasad, Chunchu B. (Inventor); Stockum, Robert W. (Inventor)

    1996-01-01

    A vertical dropped-weight impact test machine has a dropped-weight barrel vertically supported on upper and lower support brackets. The dropped-weight barrel is chambered to receive a dropped-weight assembly having a latch pin at its upper end, a damping unit in the middle, and a tup at its lower end. The tup is adapted for gathering data during impact testing. The latch pin releasably engages a latch pin coupling assembly. The latch pin coupling assembly is attached to a winch via a halyard for raising and lowering the dropped-weight assembly. The lower end of the dropped-weight barrel is provided with a bounce-back arresting mechanism which is activated by the descending passage of the dropped-weight assembly. After striking the specimen, the dropped-weight assembly rebounds vertically and is caught by the bounce-back arresting mechanism. The damping unit of the dropped-weight assembly serves to dissipate energy from the rebounding dropped-weight assembly and prevents the dropped-weight assembly from rebounding from the self-arresting mechanism.

  17. Development of small punch testing technique and its application to evaluation of mechanical properties degradation

    SciTech Connect

    Kameda, J.

    1993-10-01

    The present paper summarizes a small punch (SP) testing technique developed and its application to mechanical properties characterization. It has been clearly shown on ferritic alloys that the SP test was evaluate the intergranular embrittling potency of segregated solute, such as P, Sn and Sb causing temper embrittlement, and the effects of neutron irradiation and post-irradiation annealing, giving rise to changes in the hardness and intergranular solute segregation, on the fracture properties in terms of the ductile-brittle transition temperature (DBTT). A linear relation of the DBTT determined by the SP test to that by Charpy V-notched tests has been theoretically and experimentally established. In Al alloy substrates coated with amorphous and overlaying ceramics, moreover, the global and local fracture properties were well characterized by the SP test together with acoustic emission techniques.

  18. Rare and Low Frequency Variant Stratification in the UK Population: Description and Impact on Association Tests

    PubMed Central

    Babron, Marie-Claude; de Tayrac, Marie; Rutledge, Douglas N.

    2012-01-01

    Although variations in allele frequencies at common SNPs have been extensively studied in different populations, little is known about the stratification of rare variants and its impact on association tests. In this paper, we used Affymetrix 500K genotype data from the WTCCC to investigate if variants in three different frequency categories (below 1%, between 1 and 5%, above 5%) show different stratification patterns in the UK population. We found that these patterns are indeed different. The top principal component extracted from the rare variant category shows poor correlations with any principal component or combination of principal components from the low frequency or common variant categories. These results could suggest that a suitable solution to avoid false positive association due to population stratification would involve adjusting for the respective PCs when testing for variants in different allele frequency categories. However, we found this was not the case both on type 2 diabetes data and on simulated data. Indeed, adjusting rare variant association tests on PCs derived from rare variants does no better to correct for population stratification than adjusting on PCs derived from more common variants. Mixed models perform slightly better for low frequency variants than PC based adjustments but less well for the rarest variants. These results call for the need of new methodological developments specifically devoted to address rare variant stratification issues in association tests. PMID:23071581

  19. Rare and low frequency variant stratification in the UK population: description and impact on association tests.

    PubMed

    Babron, Marie-Claude; de Tayrac, Marie; Rutledge, Douglas N; Zeggini, Eleftheria; Génin, Emmanuelle

    2012-01-01

    Although variations in allele frequencies at common SNPs have been extensively studied in different populations, little is known about the stratification of rare variants and its impact on association tests. In this paper, we used Affymetrix 500K genotype data from the WTCCC to investigate if variants in three different frequency categories (below 1%, between 1 and 5%, above 5%) show different stratification patterns in the UK population. We found that these patterns are indeed different. The top principal component extracted from the rare variant category shows poor correlations with any principal component or combination of principal components from the low frequency or common variant categories. These results could suggest that a suitable solution to avoid false positive association due to population stratification would involve adjusting for the respective PCs when testing for variants in different allele frequency categories. However, we found this was not the case both on type 2 diabetes data and on simulated data. Indeed, adjusting rare variant association tests on PCs derived from rare variants does no better to correct for population stratification than adjusting on PCs derived from more common variants. Mixed models perform slightly better for low frequency variants than PC based adjustments but less well for the rarest variants. These results call for the need of new methodological developments specifically devoted to address rare variant stratification issues in association tests. PMID:23071581

  20. Investigation of Steven Impact Test Using a Transportation Hook Projectile with Gauged Experiments and 3D Modeling

    SciTech Connect

    Vandersall, K S; Murty, S S; Chidester, S K; Forbes, J W; Garcia, F; Greenwood, D W; Tarver, C M

    2003-07-02

    The Steven Impact Test and associated modeling offer valuable practical predictions for evaluating numerous safety scenarios involving low velocity impact of energetic materials by different projectile geometries. One such scenario is the impact of energetic material by a transportation hook during shipping, which offers complexity because of the irregular hook projectile shape. Experiments were performed using gauged Steven Test targets with PBX9404 impacted by a transportation hook projectile to compliment previous non-gauged experiments that established an impact threshold of approximately 69 m/s. Modeling of these experiments was performed with LS-DYNA code using an Ignition and Growth reaction criteria with a friction term. Comparison of the experiment to the model shows reasonable agreement with some details requiring more attention. The experimental results (including carbon resistor gauge records), model calculations, and a discussion of the dominant reaction mechanisms in light of comparisons between experiment and model will be presented.

  1. The Impact of Cooperative Learning on Critical Thinking Test Scores of Associate's Degree Graduates in Southwest Virginia

    ERIC Educational Resources Information Center

    Hodges, James Gregory

    2013-01-01

    This study examined the impact that the teaching technique known as cooperative learning had on the changes between pre- and post-test scores on all sub-categories ("induction, deduction, analysis, evaluation, inference", and "total composite") associated with the "California Critical Thinking Skills Test" (CCTST) for…

  2. Situation and context impacts the expression of personality: the influence of breeding season and test context.

    PubMed

    Haage, Marianne; Bergvall, Ulrika A; Maran, Tiit; Kiik, Kairi; Angerbjörn, Anders

    2013-11-01

    Non-human animal personality is defined as consistent behavioural differences across time and situations/contexts. Behaviours are, however, often plastic and to explain how plasticity and personality may coexist an adaptive framework has been developed. Still, there is little information on how personality is impacted by situations and contexts on an individual level. We investigated this in the European mink (Mustela lutreola) by performing a set of five experiments in two situations consisting of non-breeding and breeding season, and by using different test contexts. Three personality trait domains were identified; boldness, exploration and sociability. The levels of boldness and exploration changed between seasons but remained repeatable, which implies behavioural reaction norms and supports that the concept of personality remained applicable despite plasticity. Whilst males became bolder and more explorative in the breeding season females became shyer, which reflects European mink breeding behaviour. Furthermore, behaviours performed in mirror stimulus tests fell into different domains depending on whether, the test was conducted in the own territory or not, suggesting plasticity in the response towards conspecifics. To conclude, our results highlight the importance of situation and context for the expression of personality, and the significance of measuring multiple personality trait domains with several methods. PMID:23988476

  3. Evaluation of the hazardous impact of landfill leachates by toxicity and biodegradability tests.

    PubMed

    Kalcíková, G; Vávrová, M; Zagorc-Koncan, J; Gotvajn, A Zgajnar

    2011-01-01

    The aim of our research was to assess the ecotoxicity and biodegradability of leachates originating from two parts of a municipal landfill before and after biological treatment in the existing treatment plant. Biotests represent important tools for adequate environmental characterization of landfill leachates and could be helpful in reliable assessment and monitoring of the treatment plant efficiency. For ecotoxicity testing of landfill leachate before and after biological treatment, different organisms were chosen: the bacteria Vibrio fischeri, a mixed culture of activated sludge, duckweed Lemna minor, white mustard Sinapis alba, brine shrimp Artemia salina, and water flea Daphnia magna. For assessment of biodegradability, the method for determination of oxygen demand in a closed respirometer was used. The investigated leachates were heavily polluted, and in some cases, effluent limits were exceeded even after treatment. Results indicated that toxicity tests and physico-chemical parameters determined before and after treatment equivalently assess the efficiency of the existing treatment plant. However, the investigated leachates showed higher toxicity to Daphnia magna and especially to Lemna minor in contrast to Vibrio fischeri and Artemia salina (neither was sensitive to any of the leachates). No leachates were readily biodegradable. Experiments confirmed that the battery of toxicity tests should be applied for more comprehensive assessment of landfill leachate treatment and for reliable assessment of the treated leachate's subsequent environmental impact. It was confirmed that treated leachate, in spite of its better physico-chemical characteristics, still represents a potential environmental risk and thus should not be released into the environment. PMID:21970176

  4. Reconstruction of dynamic forces during impact tests of a crushable structure

    SciTech Connect

    Bateman, V.I.; Carne, T.G.; Mayes, R.L.; Davie, N.T.

    1993-12-31

    A force reconstruction technique is being used to assess the dynamic performance of a crushable structure (a bomb nose) in both the axial (90{degree}) and slapdown (30{degree}) impact conditions. The dynamic force characteristics for the current nose design, determined from these tests, will be used to write a dynamic force specification for a new nose design that will replace the current nose. Two structures for experimentally determining the dynamic force -- deflection characteristics of the old and new noses have been designed and constructed. One structure has the same dynamic characteristics as the bomb and is being used for axial and slapdown orientations with rocket-propelled testing. The second structure has the same mass as the bomb and is being used for iterative axial testing of candidate designs with a pneumatic ram. The structural characteristics of these two structures have been determined and are presented. A force reconstruction algorithm using the Sum of Weighted Accelerations Technique (SWAT) has been developed for each of the two structures. The force reconstruction algorithms have been verified for both structures using laboratory data. The force reconstruction process and the resulting algorithms are described. Data verifying the force reconstruction algorithms is presented.

  5. Flight test experience and controlled impact of a remotely piloted jet transport aircraft

    NASA Technical Reports Server (NTRS)

    Horton, Timothy W.; Kempel, Robert W.

    1988-01-01

    The Dryden Flight Research Center Facility of NASA Ames Research Center (Ames-Dryden) and the FAA conducted the controlled impact demonstration (CID) program using a large, four-engine, remotely piloted jet transport airplane. Closed-loop primary flight was controlled through the existing onboard PB-20D autopilot which had been modified for the CID program. Uplink commands were sent from a ground-based cockpit and digital computer in conjunction with an up-down telemetry link. These uplink commands were received aboard the airplane and transferred through uplink interface systems to the modified PB-20D autopilot. Both proportional and discrete commands were produced by the ground system. Prior to flight tests, extensive simulation was conducted during the development of ground-based digital control laws. The control laws included primary control, secondary control, and racetrack and final approach guidance. Extensive ground checks were performed on all remotely piloted systems; however, piloted flight tests were the primary method and validation of control law concepts developed from simulation. The design, development, and flight testing of control laws and systems required to accomplish the remotely piloted mission are discussed.

  6. Hypervelocity Impact Test Fragment Modeling: Modifications to the Fragment Rotation Analysis and Lightcurve Code

    NASA Technical Reports Server (NTRS)

    Gouge, Michael F.

    2011-01-01

    Hypervelocity impact tests on test satellites are performed by members of the orbital debris scientific community in order to understand and typify the on-orbit collision breakup process. By analysis of these test satellite fragments, the fragment size and mass distributions are derived and incorporated into various orbital debris models. These same fragments are currently being put to new use using emerging technologies. Digital models of these fragments are created using a laser scanner. A group of computer programs referred to as the Fragment Rotation Analysis and Lightcurve code uses these digital representations in a multitude of ways that describe, measure, and model on-orbit fragments and fragment behavior. The Dynamic Rotation subroutine generates all of the possible reflected intensities from a scanned fragment as if it were observed to rotate dynamically while in orbit about the Earth. This calls an additional subroutine that graphically displays the intensities and the resulting frequency of those intensities as a range of solar phase angles in a Probability Density Function plot. This document reports the additions and modifications to the subset of the Fragment Rotation Analysis and Lightcurve concerned with the Dynamic Rotation and Probability Density Function plotting subroutines.

  7. Testing for "snowballing" hybrid incompatibilities in Solanum: impact of ancestral polymorphism and divergence estimates.

    PubMed

    Städler, Thomas; Florez-Rueda, Ana Marcela; Paris, Margot

    2012-01-01

    Two recent high-profile studies offered empirical evidence for a "snowballing" accumulation of postzygotic incompatibilities in Drosophila and Solanum (tomatoes). Here we present a reanalysis of the Solanum data that is motivated by population genetic principles. Specifically, the high levels of intraspecific nucleotide polymorphism in wild tomato species and presumably large effective population size throughout the divergence history of this clade imply that ancestral polymorphism should be taken into account when evaluating sequence divergence between species. Based on our reanalyses of synonymous-site divergence between the four focal Solanum species and a wide range of ancestral polymorphism, we assessed under which conditions the reported accumulation of seed sterility factors supports the snowball effect. Our results highlight the pivotal impact of levels of ancestral polymorphism and alternate divergence values, and they illustrate that robust tests of the snowball effect in Solanum require genome-wide estimates of divergence. PMID:21890474

  8. Near field effects and estimation of Poisson's ratio in impact-echo thickness testing

    NASA Astrophysics Data System (ADS)

    Baggens, Oskar; Rydén, Nils

    2015-03-01

    Based on the polarization and shape of the first symmetric Lamb mode at the zero-group velocity point (S1-ZGV), a novel approach for Impact-Echo thickness testing is proposed. In this new approach all three plate parameters (thickness, velocity and Poisson's ratio) are estimated from the same wave mode (S1-ZGV). A traditional approach based on a measurement of the longitudinal- and Rayleigh wave velocity along the surface is also studied, and is found to be influenced by near field effects leading to an underestimated thickness. In addition, an alternative approach which estimates Poisson's ratio from the frequency ratio of the S1-ZGV and A2-ZGV point is discussed. The three studied approaches are demonstrated in a realistic field case.

  9. Gravitational Capture and Scattering of Straight Test Strings with Large Impact Parameters

    E-print Network

    Don N. Page

    1998-04-30

    The capture or scattering of an initially straight infinite test cosmic string by a Kerr-Newman black hole, or by any other small source of an electrovac gravitational field, is analyzed analytically when the string moves with initial velocity v and large impact parameter b >> M so that the string stays very nearly straight (except during the final capture process, if that occurs, or except far behind the gravitating object, if b is not much greater than the energy of the object in the frame of the string). The critical impact parameter for capture at low velocities is shown to be [(pi/2)(M^2-Q^2)/v]^{1/2}. For all larger b, the displacement of the string from the plane of the gravitating object after the scattering approaches the final value [b^2 - (pi/2)(M^2-Q^2)/v]^{1/2} - 2 pi M v/(1-v^2)^{1/2}, for any v, so long as b >> M.

  10. Cannabinoids & Stress: impact of HU-210 on behavioral tests of anxiety in acutely stressed mice.

    PubMed

    Kinden, Renee; Zhang, Xia

    2015-05-01

    Anxiety disorders are one of the most prevalent classes of mental disorders affecting the general population, but current treatment strategies are restricted by their limited efficacy and side effect profiles. Although the cannabinoid system is speculated to be a key player in the modulation of stress responses and emotionality, the vast majority of current research initiatives had not incorporated stress exposure into their experimental designs. This study was the first to investigate the impact of exogenous cannabinoid administration in an acutely stressed mouse model, where CD1 mice were pre-treated with HU-210, a potent CB1R agonist, prior to acute stress exposure and subsequent behavioral testing. Exogenous cannabinoid administration induced distinct behavioral phenotypes in stressed and unstressed mice. While low doses of HU-210 were anxiolytic in unstressed subjects, this effect was abolished when mice were exposed to an acute stressor. The administration of higher HU-210 doses in combination with acute stress exposure led to severe locomotor deficits that were not previously observed at the same dose in unstressed subjects. These findings suggest that exogenous cannabinoids and acute stress act synergistically in an anxiogenic manner. This study underlies the importance of including stress exposure into future anxiety-cannabinoid research due to the differential impact of cannabinoid administration on stressed and unstressed subjects. PMID:25707713

  11. Passive skeletal muscle response to impact loading: experimental testing and inverse modelling.

    PubMed

    Takaza, Michael; Moerman, Kevin M; Simms, Ciaran K

    2013-11-01

    Appropriate mechanical representation of passive muscle tissue is crucial for human body impact modelling. In this paper the experimental and modelling results of compressive loading of freshly slaughtered porcine muscle samples using a drop-tower testing rig are reported. Fibre and cross-fibre compression tests at strain rates varying from 11,600%/s to 37,800%/s were performed. Experimental results show a nonlinear stress-stretch relationship as well as a clear rate dependency of the stress. The mean (standard deviation) engineering stress in the fibre direction at a stretch of 0.7 was 22.47 kPa (5.34 kPa) at a strain rate of 22,000%/s and 38.11k Pa (5.41 kPa) at a strain rate of 37,800%/s. For the cross-fibre direction, the engineering stresses were 5.95 kPa (1.12 kPa) at a strain rate of 11,600%/s, 25.52 kPa (5.12 kPa) at a strain rate of 22,000%/s and 43.66 kPa (6.62 kPa) at a strain rate of 37,800%/s. Significant local strain variations were observed, as well as an average mass loss of 8% due to fluid exudation, highlighting the difficulties in these kinds of tests. The inverse analysis shows for the first time that the mechanical response in terms of both applied load and tissue deformation for each of the strain rates can be captured using a 1st order Ogden hyperelastic material law extended with a three-term quasilinear viscoelastic (QVL) expansion to model viscoelastic effects. An optimisation procedure was used to derive optimal material parameters for which the error in the predicted boundary condition force at maximum compression was less than 3% for all three rates of testing (11,600%/s, 22,000%/s and 37,800%/s). This model may be appropriate for whole body impact modelling at these rates. PMID:23707599

  12. Hydraulic impact end effector final test report. Automation and robotics section, ER/WM-AT Program

    SciTech Connect

    Couture, S.

    1994-02-18

    One tool being developed for dislodging and fragmenting the hard salt cake waste in the single-shell nuclear waste tanks at the Hanford Reservation near Richland, Washington, is the hydraulic impact end effector (HIEE). This total operates by discharging 11-in. slugs of water at ultrahigh pressures. The HIEE was designed, built, and initially tested in 1992. Work in 1993 included advanced developments of the HIEE to further investigate its fragmentation abilities and to determine more effective operating procedures. These tests showed that more fragmentation can be achieved by increasing the charge pressure of 40 kpsi to 55 kpsi and by the use of different operating procedures. The size of the material and the impact energy of the water slug fired from the HIEE are believed to be major factors in material fragmentation. The material`s ability to fracture also appears to depend on the distance a fracture or crack line must travel to a free surface. Thus, larger material is more difficult to fracture than smaller material. Discharge pressures of 40 kpsi resulted in little penetration or fracturing of the material. At 55 kpsi, however, the size and depth of the fractures increased. Nozzle geometry had a significant effect on fragment size and quantity. Fragmentation was about an order of magnitude greater when the HIEE was discharged into drilled holes rather than onto the material surface. Since surface shots tend to create craters, a multi-shot procedure, coupled with an advanced nozzle design, was used to drill (crater) deep holes into large material. With this procedure, a 600-lb block was reduced to smaller pieces without the use of any additional equipment. Through this advanced development program, the HIEE has demonstrated that it can quickly fragment salt cake material into small, easily removable fragments. The HIEE`s material fragmentation ability can be substantially increased through the use of different nozzle geometries and operating procedures.

  13. The Impact of Data-Based Science Instruction on Standardized Test Performance

    NASA Astrophysics Data System (ADS)

    Herrington, Tia W.

    Increased teacher accountability efforts have resulted in the use of data to improve student achievement. This study addressed teachers' inconsistent use of data-driven instruction in middle school science. Evidence of the impact of data-based instruction on student achievement and school and district practices has been well documented by researchers. In science, less information has been available on teachers' use of data for classroom instruction. Drawing on data-driven decision making theory, the purpose of this study was to examine whether data-based instruction impacted performance on the science Criterion Referenced Competency Test (CRCT) and to explore the factors that impeded its use by a purposeful sample of 12 science teachers at a data-driven school. The research questions addressed in this study included understanding: (a) the association between student performance on the science portion of the CRCT and data-driven instruction professional development, (b) middle school science teachers' perception of the usefulness of data, and (c) the factors that hindered the use of data for science instruction. This study employed a mixed methods sequential explanatory design. Data collected included 8th grade CRCT data, survey responses, and individual teacher interviews. A chi-square test revealed no improvement in the CRCT scores following the implementation of professional development on data-driven instruction (chi 2 (1) = .183, p = .67). Results from surveys and interviews revealed that teachers used data to inform their instruction, indicating time as the major hindrance to their use. Implications for social change include the development of lesson plans that will empower science teachers to deliver data-based instruction and students to achieve identified academic goals.

  14. Logic Design for On-Chip Test Clock Generation - Implementation Details and Impact on Delay Test Quality

    Microsoft Academic Search

    Matthias Beck; Olivier Barondeau; Martin Kaibel; Frank Poehl; Xijiang Lin

    2005-01-01

    This paper addresses delay test for SOC devices with high frequency clock domains. A logic design for on-chip high-speed clock generation, implemented to avoid expensive test equipment, is described in detail. Techniques for on-chip clock generation, meant to reduce test vector count and to increase test quality, are discussed. ATPG results for the proposed techniques are given.

  15. Methods for data reduction and loads analysis of Space Shuttle Solid Rocket Booster model water impact tests

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The methodology used to predict full scale space shuttle solid rocket booster (SRB) water impact loads from scale model test data is described. Tests conducted included 12.5 inch and 120 inch diameter models of the SRB. Geometry and mass characteristics of the models were varied in each test series to reflect the current SRB baseline configuration. Nose first and tail first water entry modes were investigated with full-scale initial impact vertical velocities of 40 to 120 ft/sec, horizontal velocities of 0 to 60 ft/sec., and off-vertical angles of 0 to plus or minus 30 degrees. The test program included a series of tests with scaled atmospheric pressure.

  16. Results from the car-coupling impact tests of intermodal trailers and containers. Final report, 1985-1987

    SciTech Connect

    Johnson, M.R.

    1988-03-01

    Results are presented from car-coupling impact and lift/drop tests conducted in April 1985 under the Safety Evaluation of Intermodal and Jumbo Tank Hazardous Material Cars Program. The program was conducted to develop information for analyzing the safety of transporting hazardous material containers by rail in trailer-on-flat-car or container-on-flat-car service. The 106 car-coupling impact tests included 10 different arrangements of cargo tanks (tank trailers) and intermodal tank containers mounted on a flat car. No tendency for trailers or containers to become dislodged during impact was observed, properties of end-of-car cushioning devices were found to be different at each end of the car, and drop tests caused significant damage to support legs of the tank trailers.

  17. DebriSat: The New Hypervelocity Impact Test for Satellite Breakup Fragment Characterization

    NASA Technical Reports Server (NTRS)

    Cowardin, Heather

    2015-01-01

    To replicate a hyper-velocity fragmentation event using modern-day spacecraft materials and construction techniques to better improve the existing DoD and NASA breakup models: DebriSat is intended to be representative of modern LEO satellites. Major design decisions were reviewed and approved by Aerospace subject matter experts from different disciplines. DebriSat includes 7 major subsystems. Attitude determination and control system (ADCS), command and data handling (C&DH), electrical power system (EPS), payload, propulsion, telemetry tracking and command (TT&C), and thermal management. To reduce cost, most components are emulated based on existing design of flight hardware and fabricated with the same materials. center dotA key laboratory-based test, Satellite Orbital debris Characterization Impact Test (SOCIT), supporting the development of the DoD and NASA satellite breakup models was conducted at AEDC in 1992. Breakup models based on SOCIT have supported many applications and matched on-orbit events reasonably well over the years.

  18. Standard Test Method for Impact Resistance of Monolithic Polycarbonate Sheet by Means of a Falling Weight

    E-print Network

    American Society for Testing and Materials. Philadelphia

    1995-01-01

    1.1 This test method covers the determination of the energy required to initiate failure in monolithic polycarbonate sheet material under specified conditions of impact using a free falling weight. 1.2 Two specimen types are defined as follows: 1.2.1 Type A consists of a flat plate test specimen and employs a clamped ring support. 1.2.2 Type B consists of a simply supported three-point loaded beam specimen (Fig. 1) and is recommended for use with material which can not be failed using the Type A specimen. For a maximum drop height of 6.096 m (20 ft) and a maximum drop weight of 22.68 kg (50 lb), virgin polycarbonate greater than 12.70 mm (1/2 in.) thick will probably require use of the Type B specimen. Note 1 - See also ASTM Methods: D 1709, D 2444 and D 3029. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of reg...

  19. Field tests for ground thermal properties -- Methods and impact on ground-source heat pump design

    SciTech Connect

    Kavanaugh, S.P.

    2000-07-01

    A critical need in the design procedure of closed-loop, ground-source heat pumps (GSHPs) is an accurate knowledge of the thermal properties of soil/rock formations. These properties can be estimated in the field by installing and imposing a thermal load on a ground heat exchanger at the site. Recent developments have improved the capability of predicting thermal properties from the resulting temperature change. An additional benefit is that drilling conditions, determined during the installation of the test heat exchanger, will improve the capability of contractors to estimate project costs. This paper discusses several of the issues and procedures in the development of field tests for thermal property determination. It also addresses the impact of thermal property measurement error upon the resulting ground heat exchanger design, loop operating temperatures, equipment capacity, and system efficiency. A design program that has been evaluated (Thorton et al. 1997) was used to predict results for a 100-ton (351 kW) office building. A 10% variation in thermal conductivity and diffusivity resulted in a 4.5% to 5.8% error in design length, a 1% change in cooling capacity, a +2 F (1 C) variation in loop temperature, a 0.7% change in heating capacity, a 2% variation in cooling EER, and no change in heating COP.

  20. Determination of dynamic fracture-initiation toughness using a novel impact bend test procedure

    SciTech Connect

    Yokoyama, T. (Osaka Univ. (Japan). Faculty of Engineering Okayama Univ. of Science (Japan). Dept. of Mechanical Engineering)

    1993-11-01

    A novel impact bend test procedure is described for determining the dynamic fracture-initiation toughness, K[sub Id], at a loading rate (stress intensity factor rate), K[sub I], of the order of 10[sup 6] MPa [radical]m/s. A special arrangement of the split Hopkinson pressure bar is adopted to measure accurately dynamic loads applied to a fatigue-precracked bend specimen. The dynamic stress intensity factor history for the bend specimen is evaluated by means of a dynamic finite element technique. The onset of crack initiation is detected using a string gage attached on the side of the specimen near a crack tip. The value of K[sub Id] is determined from the critical dynamic stress intensity factor at crack initiation. A series of dynamic fracture tests is carried out on a 7075-T6 aluminum alloy, a Ti-6246 alloy and an AISI 4340 steel. The K[sub Id] values obtained for the three structural materials are compared with the corresponding values obtained under quasi-static loading conditions.

  1. Instrumented impact testing of fabric-reinforced composite materials. Research and development report

    SciTech Connect

    Juska, T.D.; Crane, R.M.; Mixon, T.

    1989-05-01

    Instrumented impact and ultrasonic inspection were used to assess the impact damage resistance of six fabric-reinforced laminates. Polyester and vinylester resins reinforced with woven roving, biaxial reinforcement, and glass/Kevlar hybrid were evaluated. Biaxial fabric reinforced resins had the best impact resistance. This determination is based on the ability of these materials to survive impact with the lowest friction of impact energy resulting in damage. In addition laminates with biaxial reinforcement ahd comparable damage areas to the other materials.

  2. Test Report for MSFC Test No. 83-2: Pressure scaled water impact test of a 12.5 inch diameter model of the Space Shuttle solid rocket booster filament wound case and external TVC PCD

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Water impact tests using a 12.5 inch diameter model representing a 8.56 percent scale of the Space Shuttle Solid Rocket Booster configuration were conducted. The two primary objectives of this SRB scale model water impact test program were: 1. Obtain cavity collapse applied pressure distributions for the 8.56 percent rigid body scale model FWC pressure magnitudes as a function of full-scale initial impact conditions at vertical velocities from 65 to 85 ft/sec, horizontal velocities from 0 to 45 ft/sec, and angles from -10 to +10 degrees. 2. Obtain rigid body applied pressures on the TVC pod and aft skirt internal stiffener rings at initial impact and cavity collapse loading events. In addition, nozzle loads were measured. Full scale vertical velocities of 65 to 85 ft/sec, horizontal velocities of 0 to 45 ft/sec, and impact angles from -10 to +10 degrees simulated.

  3. Impacts Analyses Supporting the National Environmental Policy Act Environmental Assessment for the Resumption of Transient Testing Program

    SciTech Connect

    Annette L. Schafer; LLoyd C. Brown; David C. Carathers; Boyd D. Christensen; James J. Dahl; Mark L. Miller; Cathy Ottinger Farnum; Steven Peterson; A. Jeffrey Sondrup; Peter V. Subaiya; Daniel M. Wachs; Ruth F. Weiner

    2014-02-01

    This document contains the analysis details and summary of analyses conducted to evaluate the environmental impacts for the Resumption of Transient Fuel and Materials Testing Program. It provides an assessment of the impacts for the two action alternatives being evaluated in the environmental assessment. These alternatives are (1) resumption of transient testing using the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory (INL) and (2) conducting transient testing using the Annular Core Research Reactor (ACRR) at Sandia National Laboratory in New Mexico (SNL/NM). Analyses are provided for radiologic emissions, other air emissions, soil contamination, and groundwater contamination that could occur (1) during normal operations, (2) as a result of accidents in one of the facilities, and (3) during transport. It does not include an assessment of the biotic, cultural resources, waste generation, or other impacts that could result from the resumption of transient testing. Analyses were conducted by technical professionals at INL and SNL/NM as noted throughout this report. The analyses are based on bounding radionuclide inventories, with the same inventories used for test materials by both alternatives and different inventories for the TREAT Reactor and ACRR. An upper value on the number of tests was assumed, with a test frequency determined by the realistic turn-around times required between experiments. The estimates provided for impacts during normal operations are based on historical emission rates and projected usage rates; therefore, they are bounding. Estimated doses for members of the public, collocated workers, and facility workers that could be incurred as a result of an accident are very conservative. They do not credit safety systems or administrative procedures (such as evacuation plans or use of personal protective equipment) that could be used to limit worker doses. Doses estimated for transportation are conservative and are based on transport of the bounding radiologic inventory that will be contained in any given test. The transportation analysis assumes all transports will contain the bounding inventory.

  4. The Arctic as a test case for an assessment of climate impacts on national security.

    SciTech Connect

    Taylor, Mark A.; Zak, Bernard Daniel; Backus, George A.; Ivey, Mark D.; Boslough, Mark Bruce Elrick

    2008-11-01

    The Arctic region is rapidly changing in a way that will affect the rest of the world. Parts of Alaska, western Canada, and Siberia are currently warming at twice the global rate. This warming trend is accelerating permafrost deterioration, coastal erosion, snow and ice loss, and other changes that are a direct consequence of climate change. Climatologists have long understood that changes in the Arctic would be faster and more intense than elsewhere on the planet, but the degree and speed of the changes were underestimated compared to recent observations. Policy makers have not yet had time to examine the latest evidence or appreciate the nature of the consequences. Thus, the abruptness and severity of an unfolding Arctic climate crisis has not been incorporated into long-range planning. The purpose of this report is to briefly review the physical basis for global climate change and Arctic amplification, summarize the ongoing observations, discuss the potential consequences, explain the need for an objective risk assessment, develop scenarios for future change, review existing modeling capabilities and the need for better regional models, and finally to make recommendations for Sandia's future role in preparing our leaders to deal with impacts of Arctic climate change on national security. Accurate and credible regional-scale climate models are still several years in the future, and those models are essential for estimating climate impacts around the globe. This study demonstrates how a scenario-based method may be used to give insights into climate impacts on a regional scale and possible mitigation. Because of our experience in the Arctic and widespread recognition of the Arctic's importance in the Earth climate system we chose the Arctic as a test case for an assessment of climate impacts on national security. Sandia can make a swift and significant contribution by applying modeling and simulation tools with internal collaborations as well as with outside organizations. Because changes in the Arctic environment are happening so rapidly, a successful program will be one that can adapt very quickly to new information as it becomes available, and can provide decision makers with projections on the 1-5 year time scale over which the most disruptive, high-consequence changes are likely to occur. The greatest short-term impact would be to initiate exploratory simulations to discover new emergent and robust phenomena associated with one or more of the following changing systems: Arctic hydrological cycle, sea ice extent, ocean and atmospheric circulation, permafrost deterioration, carbon mobilization, Greenland ice sheet stability, and coastal erosion. Sandia can also contribute to new technology solutions for improved observations in the Arctic, which is currently a data-sparse region. Sensitivity analyses have the potential to identify thresholds which would enable the collaborative development of 'early warning' sensor systems to seek predicted phenomena that might be precursory to major, high-consequence changes. Much of this work will require improved regional climate models and advanced computing capabilities. Socio-economic modeling tools can help define human and national security consequences. Formal uncertainty quantification must be an integral part of any results that emerge from this work.

  5. Test evaluation of shock buffering concept for hydrodynamic ram induced by yawing projectile impacting a simulated integral fuel tank

    NASA Technical Reports Server (NTRS)

    Zabel, P. H.

    1979-01-01

    A concept for containing the shock inputs due to hydrodynamic ram caused by an impacting projectile within a fuel cell is discussed. This is to provide a buffering layer of foam, flexible, rigid or a combination thereof, which is sealed from the liquid. A program is described in which this buffering concept was tested. The effectiveness of a novel muzzle-mounted, 'tumble', test device is shown.

  6. Results of Two-Stage Light-Gas Gun Development Efforts and Hypervelocity Impact Tests of Advanced Thermal Protection Materials

    NASA Technical Reports Server (NTRS)

    Cornelison, C. J.; Watts, Eric T.

    1998-01-01

    Gun development efforts to increase the launching capabilities of the NASA Ames 0.5-inch two-stage light-gas gun have been investigated. A gun performance simulation code was used to guide initial parametric variations and hardware modifications, in order to increase the projectile impact velocity capability to 8 km/s, while maintaining acceptable levels of gun barrel erosion and gun component stresses. Concurrent with this facility development effort, a hypervelocity impact testing series in support of the X-33/RLV program was performed in collaboration with Rockwell International. Specifically, advanced thermal protection system materials were impacted with aluminum spheres to simulate impacts with on-orbit space debris. Materials tested included AETB-8, AETB-12, AETB-20, and SIRCA-25 tiles, tailorable advanced blanket insulation (TABI), and high temperature AFRSI (HTA). The ballistic limit for several Thermal Protection System (TPS) configurations was investigated to determine particle sizes which cause threshold TPS/structure penetration. Crater depth in tiles was measured as a function of impact particle size. The relationship between coating type and crater morphology was also explored. Data obtained during this test series was used to perform a preliminary analysis of the risks to a typical orbital vehicle from the meteoroid and space debris environment.

  7. Impact testing and simulation of composite sandwich structures for civil transportation

    Microsoft Academic Search

    L Torre; J. M Kenny

    2000-01-01

    The impact response of sandwich panels with an improved structure to increase their impact resistance is investigated herein. In order to compare the impact performance of sandwich structures, a specific and instrumented ball drop tester was designed and developed. Two different sandwich structures are analyzed: the first type is a classical structure composed by a glass fiber-polyester matrix-composite skin and

  8. General-purpose heat source: Research and development program. Radioisotope thermoelectric generator impact tests: RTG-1 and RTG-2

    SciTech Connect

    Reimus, M.A.H.; Hinckley, J.E.; George, T.G.

    1996-07-01

    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). Because the potential for a launch abort or return from orbit exists for any space mission, the heat source response to credible accident scenarios is being evaluated. The first two RTG Impact Tests were designed to provide information on the response of a fully loaded RTG to end-on impact against a concrete target. The results of these tests indicated that at impact velocities up to 57 m/s the converter shell and internal components protect the GPHS capsules from excessive deformation. At higher velocities, some of the internal components of the RTG interact with the GPHS capsules to cause excessive localized deformation and failure.

  9. Microbial Rock Inhabitants Survive Hypervelocity Impacts on Mars-Like Host Planets: First Phase of Lithopanspermia Experimentally Tested

    Microsoft Academic Search

    Gerda Horneck; Dieter Stöffler; Sieglinde Ott; Ulrich Hornemann; Charles S. Cockell; Ralf Moeller; Cornelia Meyer; Jean-Pierre de Vera; Jörg Fritz; Sara Schade; Natalia A. Artemieva

    2008-01-01

    The scenario of lithopanspermia describes the viable transport of microorganisms via meteorites. To test the first step of lithopanspermia, i.e., the impact ejection from a planet, systematic shock recovery experiments within a pressure range observed in martian meteorites (550 GPa) were performed with dry layers of microorganisms (spores of Bacillus subtilis, cells of the endolithic cyanobacterium Chroococcidiopsis, and thalli and

  10. Testing the Impact of Job-Related Variables on a Utility Judgment Training Criterion beyond Background and Affective Reaction Variables

    ERIC Educational Resources Information Center

    Blau, Gary; Gibson, Greg; Bentley, Melissa; Chapman, Susan

    2012-01-01

    We tested the incremental impact of a job-related set of variables for explaining a utility judgment training effectiveness variable, that is, course completion skill preparedness, beyond background and course-related variables. Our respondents were two different emergency medical service samples, 415 basics and 742 paramedics, from the 2008 US…

  11. Evaluating the Impact of THC in Hemp Foods and Cosmetics on Human Health and Workplace Drug Tests

    Microsoft Academic Search

    Franjo Grotenhermen; Gero Leson; Petra Pless

    2003-01-01

    In recent years, the presence of trace residual delta-9-tetrahydrocannabinol (THC) in food and cosmetics from hemp seed and seed derivatives (oil, hulled seed) has raised concerns over THC's potentially adverse impacts on human health and on the results of workplace drug tests for marijuana. Two desktop studies and one experimental study were conducted to evaluate whether (1) the ingestion of

  12. High-Stakes Testing under the No Child Left Behind Act: How Has It Impacted School Culture?

    ERIC Educational Resources Information Center

    Tingey, RaShel Anderson

    2009-01-01

    The purpose of this study was to investigate the impact of high-stakes testing under the No Child Left Behind (NCLB) Act on school culture. Individual interviews and focus groups were conducted with first grade through sixth grade teachers and principals from two of Nebo School District's schools located in Utah. Their responses were categorized…

  13. Micro-impact test on lead-free BGA balls on Au\\/electrolytic Ni\\/Cu bond pad

    Microsoft Academic Search

    Shengquan Ou; Yuhuan Xu; K. N. Tu; M. O. Alam; Y. C. Chan

    2005-01-01

    The most frequent failure of wireless, handheld, and movable consumer electronic products is an accidental drop to the ground. The impact may cause interfacial fracture of wire-bonds or solder joints between a Si chip and its packaging module. Existing metrologies, such as ball shear, and pull test cannot well represent the shock reliability of the package. In our study, a

  14. Using item response theory to calibrate the Headache Impact Test (HIT™) to the metric of traditional headache scales

    Microsoft Academic Search

    Jakob B. Bjorner; Mark Kosinski; John E. Ware Jr

    2003-01-01

    Background: Item response theory (IRT) scoring of health status questionnaires offers many advantages. However, to ensure ‘backwards comparability’ and to facilitate interpretations of results, we need the ability to express the IRT score in the metrics of the traditional scales. Objectives: To develop procedures to calibrate IRT-based scores on the Headache Impact Test (HIT) into the metrics of the traditional

  15. Field-testing IMPACT EPIC research results in Itanium 2 John W. Sias Sain-zee Ueng Geoff A. Kent

    E-print Network

    Hwu, Wen-mei W.

    Field-testing IMPACT EPIC research results in Itanium 2 John W. Sias Sain-zee Ueng Geoff A. Kent,ueng,gkent,isteiner,nystrom,hwu}@crhc.uiuc.edu Abstract Explicitly-Parallel Instruction Computing (EPIC) provides architectural features, including evaluation of code generated using aggres- sive, EPIC-enabled techniques in a reality-constrained mi

  16. Experimental test of the impacts of feral hogs on forest dynamics and processes in the southeastern US

    E-print Network

    Siemann, Evan

    Experimental test of the impacts of feral hogs on forest dynamics and processes in the southeastern). For animals that feed on both seeds and vegetative structures of plants, such as feral hogs or white tailed scrofa A B S T R A C T The foraging activities of nonindigenous feral hogs (Sus scrofa) create widespread

  17. Effects of test temperature and grain size on the charpy impact toughness and dynamic toughness ( K ID ) of polycrystalline niobium

    Microsoft Academic Search

    D. Padhi; J. J. Lewandowski

    2003-01-01

    The effects of changes in test temperature (-196 °C to 25 °C) and grain size (40 to 165 µm) on the dynamic cleavage fracture toughness ( K ID ) and Charpy impact toughness of polycrystalline niobium (Nb) have been investigated. The ductile-to-brittle transition was found to be affected by both changes in grain size and the severity of stress concentration

  18. Dual axis radiographic hydrodynamic test facility. Final environmental impact statement, Volume 2: Public comments and responses

    SciTech Connect

    NONE

    1995-08-01

    On May 12, 1995, the U.S. Department of Energy (DOE) issued the draft Dual Axis Radiographic Hydrodynamic Test Facility Environmental Impact Statement (DARHT EIS) for review by the State of New Mexico, Indian Tribes, local governments, other Federal agencies, and the general public. DOE invited comments on the accuracy and adequacy of the draft EIS and any other matters pertaining to their environmental reviews. The formal comment period ran for 45 days, to June 26, 1995, although DOE indicated that late comments would be considered to the extent possible. As part of the public comment process, DOE held two public hearings in Los Alamos and Santa Fe, New Mexico, on May 31 and June 1, 1995. In addition, DOE made the draft classified supplement to the DARHT EIS available for review by appropriately cleared individuals with a need to know the classified information. Reviewers of the classified material included the State of New Mexico, the U.S. Environmental Protection Agency, the Department of Defense, and certain Indian Tribes. Volume 2 of the final DARHT EIS contains three chapters. Chapter 1 includes a collective summary of the comments received and DOE`s response. Chapter 2 contains the full text of the public comments on the draft DARHT EIS received by DOE. Chapter 3 contains DOE`s responses to the public comments and an indication as to how the comments were considered in the final EIS.

  19. Quantitative testing of robustness on super-omniphobic surfaces by drop impact

    E-print Network

    Thi Phuong Nhung Nguyen; Philippe Brunet; Yannick Coffinier; Rabah Boukherroub

    2010-10-11

    The quality of a liquid-repellent surface is quantified by both the apparent contact angle $\\theta_0$ that a sessile drop adopts on it, and the value of the liquid pressure threshold the surface can withstand without being impaled by the liquid, hence keeping a low-friction condition. We designed surfaces covered with nano-wires obtained by the vapor-liquid-solid (VLS) growth technique, that are able to repel most of the existing non-polar liquids including those of very low surface tension, as well as many polar liquids of moderate to high surface tension. These super-omniphobic surfaces exhibit apparent contact angles ranging from 125 to 160$^{\\circ}$ depending on the liquid. We tested the robustness of the surfaces against impalement by carrying out drop impact experiments. Our results show how this robustness depends on the Young's contact angle $\\theta_0$ related to the surface tension of the liquid, and that the orientational growth of NWs is a favorable factor for robustness.

  20. Investigations on a novel technique for experimental structural dynamics: theoretical analysis of impact testing using CSLDV

    NASA Astrophysics Data System (ADS)

    Ribichini, R.; Di Maio, D.; Stanbridge, A. B.; Ewins, D. J.

    2008-06-01

    In the past decade, Continuous Scanning Laser Doppler Velocimetry (CSLDV) has been successfully used in experimental modal analysis and vibration tests. Essentially, this technique consists in the use of a Laser Scanning Velocimeter (LDV) moving continuously across a vibrating surface rather than stepping in a point-by- point fashion. If the structure is undergoing harmonic vibration, its Operating Deflection Shape (ODS) can be recovered in a very short time and without the limitations in spatial resolution typical of discrete point measurements. Recently, this technique has been extended to transient excitation -i.e. the object is swept by the laser transducer during a period of transient free response caused by an impact. The combination of a broadband excitation with a full-field measurement results in a highly complex signal, modulated both by the mode shapes of the structure and by the exponential decays due to damping effects. Thus, the signal contains in its spectrum a mixture of temporal information (the eigenvalues of the structure) and spatial information (the eigenvectors), all in a single time history. This paper presents a mathematical model of this new concept, first applied to a simple one-dimensional scan and then to a rectangular 2-D area scan. The numerically-simulated signals of the 1-D case are compared with actual measurements, both in time and frequency domains. Finally, an analysis of the measurement parameters involved in this method is provided.

  1. Biological impact assessment of nanomaterial used in nanomedicine. introduction to the NanoTEST project.

    PubMed

    Juillerat-Jeanneret, Lucienne; Dusinska, Maria; Fjellsbø, Lise Marie; Collins, Andrew R; Handy, Richard D; Riediker, Michael

    2015-05-01

    Therapeutic nanoparticles (NPs) are used in nanomedicine as drug carriers or imaging agents, providing increased selectivity/specificity for diseased tissues. The first NPs in nanomedicine were developed for increasing the efficacy of known drugs displaying dose-limiting toxicity and poor bioavailability and for enhancing disease detection. Nanotechnologies have gained much interest owing to their huge potential for applications in industry and medicine. It is necessary to ensure and control the biocompatibility of the components of therapeutic NPs to guarantee that intrinsic toxicity does not overtake the benefits. In addition to monitoring their toxicity in vitro, in vivo and in silico, it is also necessary to understand their distribution in the human body, their biodegradation and excretion routes and dispersion in the environment. Therefore, a deep understanding of their interactions with living tissues and of their possible effects in the human (and animal) body is required for the safe use of nanoparticulate formulations. Obtaining this information was the main aim of the NanoTEST project, and the goals of the reports collected together in this special issue are to summarise the observations and results obtained by the participating research teams and to provide methodological tools for evaluating the biological impact of NPs. PMID:23875681

  2. Damage evolution in GLARE fibre-metal laminate under repeated low-velocity impact tests

    NASA Astrophysics Data System (ADS)

    Morinière, Freddy; Alderliesten, René; Tooski, Mehdi; Benedictus, Rinze

    2012-12-01

    An experimental study was performed on the repeated low-velocity impact behaviour of GLARE. Damage evolution in the material constituents was characterised with successive number of impacts. Records were correlated with visual inspection, ultrasound C-scan and chemical etching. The stiffness of the plate varied when cumulating the number of impacts. Damage accumulation was limited thanks to the synthesis of unidirectional composite and metal. The glass/epoxy plies with high elastic tensile strength could withstand several impacts before perforation despite delamination growth in the vicinity of the impacted area. The damage tolerant aluminium layers prevented the penetration of the projectile and avoided the expansion of delamination. This efficient mechanism preserved the structural integrity of GLARE until first aluminium cracking at the non-impacted side. Among the different failure modes, plate deformation absorbed most of the impact energy. The findings will support the development of a generic quasi-static analytical model and numerical methods.

  3. Impact Testing on Reinforced Carbon-Carbon Flat Panels With BX-265 and PDL-1034 External Tank Foam for the Space Shuttle Return to Flight Program

    NASA Technical Reports Server (NTRS)

    Melis, Matthew E.; Revilock, Duane M.; Pereira, Michael J.; Lyle, Karen H.

    2009-01-01

    Following the tragedy of the Orbiter Columbia (STS-107) on February 1, 2003, a major effort commenced to develop a better understanding of debris impacts and their effect on the space shuttle subsystems. An initiative to develop and validate physics-based computer models to predict damage from such impacts was a fundamental component of this effort. To develop the models it was necessary to physically characterize reinforced carbon-carbon (RCC) along with ice and foam debris materials, which could shed on ascent and impact the orbiter RCC leading edges. The validated models enabled the launch system community to use the impact analysis software LS-DYNA (Livermore Software Technology Corp.) to predict damage by potential and actual impact events on the orbiter leading edge and nose cap thermal protection systems. Validation of the material models was done through a three-level approach: Level 1-fundamental tests to obtain independent static and dynamic constitutive model properties of materials of interest, Level 2-subcomponent impact tests to provide highly controlled impact test data for the correlation and validation of the models, and Level 3-full-scale orbiter leading-edge impact tests to establish the final level of confidence for the analysis methodology. This report discusses the Level 2 test program conducted in the NASA Glenn Research Center (GRC) Ballistic Impact Laboratory with external tank foam impact tests on flat RCC panels, and presents the data observed. The Level 2 testing consisted of 54 impact tests in the NASA GRC Ballistic Impact Laboratory on 6- by 6-in. and 6- by 12-in. flat plates of RCC and evaluated two types of debris projectiles: BX-265 and PDL-1034 external tank foam. These impact tests helped determine the level of damage generated in the RCC flat plates by each projectile and validated the use of the foam and RCC models for use in LS-DYNA.

  4. Study of austenitic stainless steel welded with low alloy steel filler metal. [tensile and impact strength tests

    NASA Technical Reports Server (NTRS)

    Burns, F. A.; Dyke, R. A., Jr.

    1979-01-01

    The tensile and impact strength properties of 316L stainless steel plate welded with low alloy steel filler metal were determined. Tests were conducted at room temperature and -100 F on standard test specimens machined from as-welded panels of various chemical compositions. No significant differences were found as the result of variations in percentage chemical composition on the impact and tensile test results. The weldments containing lower chromium and nickel as the result of dilution of parent metal from the use of the low alloy steel filler metal corroded more severely in a marine environment. The use of a protective finish, i.e., a nitrile-based paint containing aluminum powder, prevented the corrosive attack.

  5. Impacts Analyses Supporting the National Environmental Policy Act Environmental Assessment for the Resumption of Transient Testing Program

    SciTech Connect

    Annette L. Schafer; Lloyd C. Brown; David C. Carathers; Boyd D. Christensen; James J. Dahl; Mark L. Miller; Cathy Ottinger Farnum; Steven Peterson; A. Jeffrey Sondrup; Peter V. Subaiya; Daniel M. Wachs; Ruth F. Weiner

    2013-11-01

    Environmental and health impacts are presented for activities associated with transient testing of nuclear fuel and material using two candidate test reactors. Transient testing involves irradiation of nuclear fuel or materials for short time-periods under high neutron flux rates. The transient testing process includes transportation of nuclear fuel or materials inside a robust shipping cask to a hot cell, removal from the shipping cask, pre-irradiation examination of the nuclear materials, assembly of an experiment assembly, transportation of the experiment assembly to the test reactor, irradiation in the test reactor, transport back to the hot cell, and post-irradiation examination of the nuclear fuel or material. The potential for environmental or health consequences during the transportation, examination, and irradiation actions are assessed for normal operations, off-normal (accident) scenarios, and transportation. Impacts to the environment (air, soil, and groundwater), are assessed during each phase of the transient testing process. This report documents the evaluation of potential consequences to the general public. This document supports the Environmental Assessment (EA) required by the U.S. National Environmental Policy Act (NEPA) (42 USC Subsection 4321 et seq.).

  6. Using simulation for assessing the real impact of test coverage on defect coverage

    Microsoft Academic Search

    Lionel C. Briand; Dietmar Pfahl

    1999-01-01

    The use of test coverage measures (e.g. block coverage) to control the software test process has become an increasingly common practice. This is justified by the assumption that higher test coverage helps achieve higher defect coverage and therefore improves software quality. In practice, data often shows that defect coverage and test coverage grow over time, as additional testing is performed.

  7. Testing

    MedlinePLUS

    ... curesma.org > learn about sma > causes & diagnoses > testing Testing An SMA diagnosis must be confirmed through genetic ... and must be identified through further testing. Prenatal Testing Prenatal testing is used to determine if a ...

  8. Impacts

    Microsoft Academic Search

    M. Hellmuth; P. Kabat

    2003-01-01

    Even without the impacts of climate change, water managers face prodigious challenges in meeting sustainable development goals. Growing populations need affordable food, water and energy. Industrial development demands a growing share of water resources and contaminates those same resources with its untreated wastes. Nature is at the back of the queue, but preserving enough flows to sustain aquatic ecosystems is

  9. Evaluation of a new battery of toxicity tests for boreal forest soils: assessment of the impact of hydrocarbons and salts.

    PubMed

    Princz, Juliska I; Moody, Mary; Fraser, Christopher; Van der Vliet, Leana; Lemieux, Heather; Scroggins, Rick; Siciliano, Steven D

    2012-04-01

    The ability to assess the toxic potential of soil contamination within boreal regions is currently limited to test species representative of arable lands. This study evaluated the use of six boreal plant species (Pinus banksiana, Picea glauca, Picea mariana, Populus tremuloides, Calamagrostis Canadensis, and Solidago canadensis) and four invertebrate species (Dendrodrilus rubidus, Folsomia nivalis, Proisotoma minuta, and Oppia nitens) and compared their performance to a suite of standard agronomic soil test species using site soils impacted by petroleum hydrocarbon (PHC) and salt contamination. To maintain horizon-specific differences, individual soil horizons were collected from impacted sites and relayered within the test vessels. Use of the boreal species was directly applicable to the assessment of the contaminated forest soils and, in the case of the hydrocarbon-impacted soil, demonstrated greater overall sensitivity (25th percentile of estimated species sensitivity distribution [ESSD25]?=?5.6% contamination: 10,600 mg/kg fraction 3 [F3; equivalent hydrocarbon range of >C16 to C34] Of/Oh horizon, and 270 mg/kg F3 Ahg horizon) relative to the standard test species (ESSD25?=?23% contamination: 44,000 mg/kg F3 Of/Oh horizon, and 1,100 mg/kg F3 Ahg horizon). For salinity, there was no difference between boreal and standard species with a combined ESSD25?=?2.3%, equating to 0.24 and 0.25 dS/m for the Ah and Ck horizons. The unequal distribution of soil invertebrates within the layered test vessels can confound test results and the interpretation of the toxic potential of a site. The use of test species relevant to boreal eco-zones strengthens the applicability of the data in support of realistic ecological risk assessments applicable to the boreal regions. PMID:22228553

  10. Testing the ureilite projectile hypothesis for the El'gygytgyn impact: Determination of siderophile element abundances and Os isotope ratios in ICDP drill core samples

    E-print Network

    Claeys, Philippe

    Testing the ureilite projectile hypothesis for the El'gygytgyn impact: Determination of siderophile with that of impact melt rock fragments collected near the western rim of the structure and literature data group elements, and isotope ratios of osmium (Os), were determined to test the hypothesis of an ureilite

  11. Introductory fatigue tests on welded joints in high strength steel and aluminium improved by various methods including ultrasonic impact treatment (UIT)

    Microsoft Academic Search

    NORWEGIAN DELEGATION; P. J. Haagensen; E. S. Statnikov; L. Lopez-Martinez

    This paper summarizes fatigue test on high strength steel specimens in the as-welded condition and specimens treated by ultrasonic impact treatment, TIG dressing and a combination of TIG dressing and ultrasonic impact treatment. Single lap joint specimens in 6 mm aluminium plate material were tested in the as-welded, hammer peened, needle peened and ground condition. Aluminium joints with longitudinal stiffeners

  12. Factors involved in evaluating ground water impacts of deep coal mine drainage. [Pumping tests of wells drilled into the coal seam and development of mathematical models; detailed discussion

    Microsoft Academic Search

    P. R. Davis; W. C. Walton

    1982-01-01

    The determination of probable ground water impacts of proposed deep coal mining is required as part of permit applications. Impact prediction generally involves well production test analysis and modeling of ground water systems associated with coal seams. Well production tests are often complicated due to the relatively low permeabilities of sandstones and shales of ground water systems. The effects of

  13. Investigation on occupant ejection in high severity rear impact based on post mortem human subject sled tests.

    PubMed

    Petit, Philippe; Luet, Carole; Potier, Pascal; Vallancien, Guy

    2011-11-01

    Occupant protection in rear impact involves two competing challenges. On one hand, allowing a deformation of the seat would act as an energy absorber in low severity impacts and would consequently decrease the risk of neck injuries. However, on the other hand, large deformations of the seat may increase the likelihood of occupant ejection in high severity cases. Green et al. 1987 analyzed a total of 919 accidents in Great Britain. They found that occupant ejection resulted in a risk of severe injuries and fatalities between 3.6 and 4.5 times higher than those cases where no ejection was observed. The sample included single front, side and rear impacts as well as multiple impacts and rollover. The rate of belt use in the sample was 50%. While this analysis included all forms of impact scenarios, nevertheless, it highlights the relative injury severity of occupant ejection. Extensive literature search has found no full-scale rear impact tests involving Post Mortem Human Subjects (PMHS) conducted in a laboratory environment and resulting in ejection. This paper describes a total of 10 sled tests conducted on 3 belted PMHS using a simplified seat design composed of rigid plates assembled such that the angular and linear stiffness of the seatback (including the foam) was modeled. The initial angular position and the range of motion of the seatback, the size of the PMHS, the slack length of the seatbelt, the angular stiffness of the seatback, and the use of headrest were varied in the test matrix while the pulse was kept constant (triangular acceleration with a peak of 17 G at 30 ms and a duration of 95 ms). In the test series, the tests were not run randomly but the likelihood of occupant ejection was increased systematically until ejection occurred. PMHS seat ejection was observed only for the 95th percentile, initially positioned with a seatback angle relative to the vertical equal to 22°, a range of seatback angular motion equal to 44° and no headrest. Repeating the test under the same conditions but with the pretentionner fired did not prevent the ejection. In addition, the 50th percentile belted specimen were not observed to sustain rearward seat ejection under realistic conditions including the use of head-rest. PMID:22869306

  14. Safety Issues in the Nuclear Electric Propulsion Space Test Environmental Impact Statement

    Microsoft Academic Search

    William A. Glover

    1994-01-01

    The National Environmental Policy Act (NEPA), requires Federal agencies to prepare environmental impact statements (EIS) for actions which might have a significant impact on the human environment. Launching a nuclear reactor into Earth orbit is such an action. Although the normal operations of the space nuclear reactor may have a minimal effect on the human environment, launch accidents, criticality accidents,

  15. Chicxulub: testing for post-impact hydrothermal inputs into the Tertiary ocean

    Microsoft Academic Search

    A. Rowe; J. Wilkinson; J. Morgan

    2003-01-01

    Large terrestrial impacts produce intense fracturing of the crust and large melt sheets, providing ideal conditions for extensive hydrothermal circulation. In marine settings, such as Chicxulub, there is the potential for downward penetration of cold seawater, heating by the thermal anomaly at the impact site and leaching of metals, prior to buoyancy driven flow back to the surface. There, fluids

  16. Testing impact attenuation on California playground surfaces made of recycled tires

    Microsoft Academic Search

    Charles Vidair; Robert Haas; Robert Schlag

    2007-01-01

    This study was conducted to determine whether rubberized playground surfaces made of recycled tires comply with state-mandated standards for impact attenuation (measured with an accelerometer), and whether their properties change in response to temperature or time. The Head Impact Criterion (HIC) standard of 1000 was found to be a more sensitive indicator of compliance than the Gmax standard of 200(g).

  17. Development of a soil test for determining the impact of soil disturbance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    United States Federal law requires land-managing agencies like the US Army to identify and take into account the impacts of their undertakings on archaeological resources. Development of a method that uses changes in the stratification of horizon interfaces to identify the onset of adverse impacts t...

  18. Understanding how pre-impact posture can affect injury outcome in side impact sled tests using a new tool for visualization of cadaver kinematics.

    PubMed

    Donlon, John Paul; Poulard, David; Lessley, David; Riley, Patrick; Subit, Damien

    2015-02-01

    The effect of posture and subject-specific factors on injury outcome is an active field of research in injury biomechanics, in particular in automotive safety research where post-mortem human subjects (PMHS) are used as surrogates. Current PMHS tests routinely include acquisition of the subjects? geometry and kinematics. However, combining these two datasets to better understand the injury mechanism is still a challenge. This study investigated the connection between pre-impact posture and resulting injuries in six previously published side impact sled tests (three with a rigid wall and three with an airbag) by creating three-dimensional kinematic animations (3DKA) of the tests. The 3DKA allow qualitative assessment of parameters related to posture and their possible effect on injury outcome. The orientation of the struck scapula and the lateral leaning of the torso were identified as potentially significant parameters. The ranges of variation in these parameters were quantified and compared to the number of rib fractures for each subject: the data suggested a correlation, but there was insufficient data for a probabilistic analysis. The 3DKA were published with this study and are freely available. PMID:25579992

  19. Assessing the impact of common forensic presumptive tests on the ability to obtain results using a novel rapid DNA platform.

    PubMed

    Donachie, Gillian E; Dawnay, Nick; Ahmed, Romana; Naif, Sarah; Duxbury, Nicola J; Tribble, Nicholas D

    2015-07-01

    The rise of DNA evidence to the forefront of forensic science has led to high sample numbers being submitted for profiling by investigators to casework laboratories: bottleneck effects are often seen resulting in slow turnaround times and sample backlog. The ParaDNA(®) Screening and Intelligence Tests have been designed to guide investigators on the viability of potential sources of DNA allowing them to determine which samples should be sent for full DNA analysis. Both tests are designed to augment the arsenal of available forensic tests for end users and be used concurrently to those commonly available. Therefore, assessing the impact that common forensic tests have on such novel technology is important to measure. The systems were tested against various potential inhibitors to which samples may be exposed as part of the investigative process. Presumptive test agents for biological materials (blood, semen and saliva) and those used as fingerprint enhancement agents were both used. The Screening Test showed a drop in performance following application of aluminium powder and cyanoacrylate (CNA) on fingerprints samples; however this drop in performance was not replicated with high template DNA. No significant effect was observed for any agent using the Intelligence Test. Therefore, both tests stand up well to the chemical agents applied and can be used by investigators with confidence that system performance will be maintained. PMID:25864157

  20. NCME 2008 Presidential Address: The Impact of Anchor Test Configuration on Student Proficiency Rates

    ERIC Educational Resources Information Center

    Fitzpatrick, Anne R.

    2008-01-01

    Examined in this study were the effects of reducing anchor test length on student proficiency rates for 12 multiple-choice tests administered in an annual, large-scale, high-stakes assessment. The anchor tests contained 15 items, 10 items, or five items. Five content representative samples of items were drawn at each anchor test length from a…

  1. Extreme resistance of super-hydrophobic surfaces to impalement: reversible electrowetting related to the impacting/bouncing drop test

    E-print Network

    P. Brunet; F. Lapierre; V. Thomy; Y. Coffinier; R. Boukherroub

    2008-09-04

    The paper reports on the comparison of the wetting properties of super-hydrophobic silicon nanowires (NWs), using drop impact impalement and electrowetting (EW) experiments. A correlation between the resistance to impalement on both EW and drop impact is shown. From the results, it is evident that when increasing the length and density of NWs: (i) the thresholds for drop impact and EW irreversibility increase (ii) the contact-angle hysteresis after impalement decreases. This suggests that the structure of the NWs network could allow for partial impalement, hence preserving the reversibility, and that EW acts the same way as an external pressure. The most robust of our surfaces show a threshold to impalement higher than 35 kPa, while most of the super-hydrophobic surfaces tested so far have impalement threshold smaller than 10 kPa.

  2. Testing Commercial Sex Workers for Sexually Transmitted Infections in Victoria, Australia: An Evaluation of the Impact of Reducing the Frequency of Testing

    PubMed Central

    Chow, Eric P. F.; Fehler, Glenda; Chen, Marcus Y.; Bradshaw, Catriona S.; Denham, Ian; Law, Matthew G.; Fairley, Christopher K.

    2014-01-01

    Background The frequency of testing sex workers for sexually transmitted infections (STIs) in Victoria, Australia, was changed from monthly to quarterly on 6 October 2012. Our aim was to determine the impact of this change to the clients seen at the Melbourne Sexual Health Centre (MHSC). Methods Computerised medical records of all clients attending at MHSC from 7 October 2011 to 7 October 2013 were analysed. Results Comparing between the monthly and quarterly testing periods, the number of consultations at MSHC with female sex workers (FSW) halved from 6146 to 3453 (p<0.001) and the consultation time spent on FSW reduced by 40.6% (1942 h to 1153 h). More heterosexual men (p<0.001), and women (p<0.001) were seen in the quarterly testing period. The number of STIs diagnosed in the clinic increased from 2243 to 2589 from the monthly to quarterly period, respectively [15.4% increase (p<0.001)]. Up to AU$247,000 was saved on FSW testing after the shift to quarterly testing. Conclusions The change to STIs screening frequency for sex workers from monthly to quarterly resulted in a 15% increase in STI diagnoses in the clinic and approximate a quarter of a million dollars was diverted from FSW testing to other clients. Overall the change in frequency is likely to have had a beneficial effect on STI control in Victoria. PMID:25048817

  3. General-purpose heat source: Research and development program, radioisotope thermoelectric generator/thin fragment impact test

    SciTech Connect

    Reimus, M.A.H.; Hinckley, J.E.

    1996-11-01

    The general-purpose heat source provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). Because the potential for a launch abort or return from orbit exists for any space mission, the heat source response to credible accident scenarios is being evaluated. This test was designed to provide information on the response of a loaded RTG to impact by a fragment similar to the type of fragment produced by breakup of the spacecraft propulsion module system. The results of this test indicated that impact by a thin aluminum fragment traveling at 306 m/s may result in significant damage to the converter housing, failure of one fueled clad, and release of a small quantity of fuel.

  4. Test-Analysis Correlation for Space Shuttle External Tank Foam Impacting RCC Wing Leading Edge Component Panels

    NASA Technical Reports Server (NTRS)

    Lyle, Karen H.

    2008-01-01

    The Space Shuttle Columbia Accident Investigation Board recommended that NASA develop, validate, and maintain a modeling tool capable of predicting the damage threshold for debris impacts on the Space Shuttle Reinforced Carbon-Carbon (RCC) wing leading edge and nosecap assembly. The results presented in this paper are one part of a multi-level approach that supported the development of the predictive tool used to recertify the shuttle for flight following the Columbia Accident. The assessment of predictive capability was largely based on test analysis comparisons for simpler component structures. This paper provides comparisons of finite element simulations with test data for external tank foam debris impacts onto 6-in. square RCC flat panels. Both quantitative displacement and qualitative damage assessment correlations are provided. The comparisons show good agreement and provided the Space Shuttle Program with confidence in the predictive tool.

  5. Assessment of impact damage in Kevlar{reg_sign}-epoxy, filament-wound spherical test specimens by acoustic emission techniques

    SciTech Connect

    Whittaker, J.W.; Brosey, W.D. [Oak Ridge Y-12 Plant, TN (United States); Hamstad, M.A. [Univ. of Denver, CO (United States). Dept. of Engineering

    1996-09-26

    The results of a study of the acoustic emission (AE) behavior of impact-damaged, spherical, composite test specimens subjected to thermal cycling and biaxial mechanical loading are presented. Seven Kevlar{reg_sign}-epoxy, filament-wound, spherical composite test specimens were subjected to different levels of impact damage. The seven specimens were a subset of a group of 77 specimens made with simulated fabrication-induced flaws. The specimens were subjected to two or three cycles of elevated temperature and then hydraulically pressurized to failure. The pressurization regime consisted of two cycles to different intermediate levels with a hold at each peak pressure level; a final pressurization to failure followed. The thermal and pressurization cycles were carefully designed to stimulate AE production under defined conditions. Both impacted and nonimpacted specimens produced thermo-AE (the term given to emission stimulated by thermal loading), but impacted specimens produced significantly more. Thermo-AE was produced primarily by damaged composite material. Damaged material produced emission as a function of both rising and falling temperature, but the effect was not repeatable. More seriously damaged specimens produced very large quantities of emission. Emission recorded during the static portion of the hydraulic loading cycles varied with load, time, and degree of damage. Static load AE behavior was quantified using a newly developed concept, the event-rate moment, and various correlations with residual strength were attempted. Correlations between residual strength, long-duration events, and even-rate moments were developed with varying degrees of success.

  6. Translating the Short-Form Headache Impact Test (HIT6) in 27 countries: Methodological and conceptual issues

    Microsoft Academic Search

    B. Gandek; J. Alacoque; V. Uzun; M. Andrew-Hobbs; K. Davis

    2003-01-01

    The process of translating the Short-Form Headache Impact Test (HIT-6) in 27 countries and the comparability of the content of the translations is discussed. HIT-6 translations were developed using a standard forward–backward translation process, including a cognitive debriefing step and international harmonization of the translations. Prior to translating the HIT-6, modifications were made to the English-language source form, to improve

  7. Dynamic fracture toughness properties of a 9Cr?1Mo weld from instrumented impact and drop-weight tests

    Microsoft Academic Search

    R. Chandramohan

    1996-01-01

    This paper reports the RTNDT and KId results obtained from instrumented impact and drop-weight tests of 9Cr?1Mo welds. RTNDT results for welds prepared using electrodes of diameter 2–5, 3–15 and 4 mm agree within 5K, the respective values being 264, 269 and 268K. For all the three welds, 269K can be taken as the conservative RTNDT. The procedures presented in

  8. Hugoniot properties for concrete determined by full-scale detonation experiments and flyer-plate-impact tests

    Microsoft Academic Search

    N. Gebbeken; S. Greulich; A. Pietzsch

    2006-01-01

    Two different and independent shock compression experiments have been performed in order to determine equation of state (EoS, Hugoniot) properties of concrete. The techniques used in the present study are full-scale detonation experiments where pressures were obtained in the affected concrete body with carbon resistor gauges, and, flyer-plate-impact tests where subsequent velocity histories were monitored by a VISAR (velocity interferometer

  9. Effects of test temperature and grain size on the charpy impact toughness and dynamic toughness ( K ID ) of polycrystalline niobium

    Microsoft Academic Search

    D. Padhi; J. J. Lewandowski

    2003-01-01

    The effects of changes in test temperature (?196 °C to 25 °C) and grain size (40 to 165 µm) on the dynamic cleavage fracture toughness (K\\u000a \\u000a ID\\u000a ) and Charpy impact toughness of polycrystalline niobium (Nb) have been investigated. The ductile-to-brittle transition was\\u000a found to be affected by both changes in grain size and the severity of stress concentration (i.e.,

  10. Beta-Testing the “Particular Machine”: The Machine-or-Transformation Test in Peril and Its Impact on Cloud Computing

    Microsoft Academic Search

    Richard M. Lee

    2012-01-01

    This Issue Brief examines recent cases addressing the patent eligibility of computer-implemented method claims and their implications for the development of cloud computing technologies. Despite the Supreme Court’s refusal to endorse the machine-or-transformation test as the exclusive patent eligibility inquiry, lower courts have continued to invalidate method claims using a stringent “particular machine” requirement alongside the requisite abstract ideas analysis.

  11. Materials, Manufacturing, and Test Development of a Composite Fan Blade Leading Edge Subcomponent for Improved Impact Resistance

    NASA Technical Reports Server (NTRS)

    Miller, Sandi G.; Handschuh, Katherine; Sinnott, Matthew J.; Kohlman, Lee W.; Roberts, Gary D.; Martin, Richard E.; Ruggeri, Charles R.; Pereira, J. Michael

    2015-01-01

    Application of polymer matrix composite materials for jet engine fan blades is becoming attractive as an alternative to metallic blades; particularly for large engines where significant weight savings are recognized on moving to a composite structure. However, the weight benefit of the composite is offset by a reduction of aerodynamic efficiency resulting from a necessary increase in blade thickness; relative to the titanium blades. Blade dimensions are largely driven by resistance to damage on bird strike. Further development of the composite material is necessary to allow composite blade designs to approximate the dimensions of a metallic fan blade. The reduction in thickness over the state of the art composite blades is expected to translate into structural weight reduction, improved aerodynamic efficiency, and therefore reduced fuel consumption. This paper presents test article design, subcomponent blade leading edge fabrication, test method development, and initial results from ballistic impact of a gelatin projectile on the leading edge of composite fan blades. The simplified test article geometry was developed to realistically simulate a blade leading edge while decreasing fabrication complexity. Impact data is presented on baseline composite blades and toughened blades; where a considerable improvement to impact resistance was recorded.

  12. Testing.

    ERIC Educational Resources Information Center

    Killoran, James, Ed.

    1984-01-01

    This journal issue addresses the issue of testing in the social studies classroom. The first article, "The Role of Testing" (Bragaw), focuses on the need for tests to reflect the objectives of the study completed. The varying functions of pop quizzes, weekly tests, and unit tests are explored. "Testing Thinking Processes" (Killoran, Zimmer, and…

  13. Evaluating the impact of genotype errors on rare variant tests of association

    E-print Network

    Cook, Kaitlyn

    The new class of rare variant tests has usually been evaluated assuming perfect genotype information. In reality, rare variant genotypes may be incorrect, and so rare variant tests should be robust to imperfect data. Errors ...

  14. Innovative practices session 3C: Industrial practices of test cost reduction techniques: Impact and design tradeoffs

    Microsoft Academic Search

    Sarveswara Tammali

    2010-01-01

    Test cost is becoming increasingly significant percentage of COB (Cost of Build) in current SoCs (System-on-a-Chip). This is even critical in low cost markets like consumer devices. This session covers test cost reduction strategy that can be adopted on a typical semiconductor product, during design and post-silicon phases. Test cost reduction during design phase includes, adoption of right DFT (Design-For-Test)

  15. The Impact of Testing Frequency on Student Performance in a Marketing Course

    ERIC Educational Resources Information Center

    Kling, Nathan; McCorkle, Denny; Miller, Chip; Reardon, James

    2005-01-01

    Testing frequency has long been examined in the social sciences as an antecedent to student performance in the classroom. However, after nearly 70 years of study, the results are inconclusive. Given the developments in computerized testing over the last decade, professors now have the ability to create and conduct frequent tests without severely…

  16. Impact of Accountability and School Testing on Students: Is There Evidence of Anxiety?

    ERIC Educational Resources Information Center

    Mulvenon, Sean W.; Connors, Joanie V.; Lenares, Denise

    The marked increases in standardized achievement testing have raised concerns of the educational community regarding the value of standardized testing programs and their potentially harmful effect on students. This study incorporated student perceptions and their views of standardized testing and combined this information with their performance on…

  17. Monitored impact loading of the hip: initial testing of a home-use device.

    PubMed

    Hans, D; Genton, L; Drezner, M K; Schott, A M; Pacifici, R; Avioli, L; Slosman, D O; Meunier, P J

    2002-08-01

    Many studies have been done involving exercise, impact loading, and the effect on BMD. In some of these studies, particularly those involving outpatient activity, compliance and the specific parameters of an individual's impact loading have been difficult to monitor effectively. In this study, an individual, home-use platform was used to record daily, specific, and reproducible impact forces generated during a heel drop exercise. At three centers over 24 months, we conducted a randomized, prospective study of 157 osteoporotic and osteopenic women, aged 60-85 years. A total of 99 patients used the home Osteocare device (OrthoGenesis Incorporated, Northborough, Massachusetts USA) to generate a reproducible and specific daily impact program (active group). Controls (32) performed a similar motion on the unit but without trying to trigger an impact force (sham group), and 26 patients did no prescribed heel drop exercise (control group). All groups had the same calcium and vitamin D supplementation. Hip DXA was performed at baseline and every 6 months during the entire study duration. Compliance with the 3-5 min routine was high, and patients were able to consistently achieve the specific targeted impact range. Pooled BMD results showed no significant differences between groups in overall BMD measurements. However, a classification model that looked at individual site-specific BMD changes showed that more than 75% of the active group responded (versus 62% for both the sham and the control groups) by maintaining or increasing site-specific hip BMD over the 2-year trial. In fact, at the end of the study, 45% of the actives were gainers versus 12% and 22% in the sham and control groups, respectively. This study suggests that hip BMD may be maintained through a brief, safe, at-home, monitored impact loading program. PMID:12200644

  18. Impact of Gene Patents and Licensing Practices on Access to Genetic Testing for Hearing Loss

    PubMed Central

    Chandrasekharan, Subhashini; Fiffer, Melissa

    2011-01-01

    Genetic testing for heritable hearing loss involves a mix of patented and unpatented genes, mutations and testing methods. More than half of all hearing loss is linked to inherited mutations, and five genes are most commonly tested in the United States. There are no patents on three of these genes, but Athena Diagnostics holds exclusive licenses to test for a common mutation in the GJB2 gene associated with about 50% of all cases, as well as mutations in the MTRNR1 gene. This fragmented intellectual property landscape made hearing loss a useful case study for assessing whether patent rights in genetic testing can proliferate or overlap, and whether it is possible to gather the rights necessary to perform testing. Testing for hearing loss is widely available, primarily from academic medical centers. Based on literature reviews and interviews with researchers, research on the genetics of hearing loss has generally not been impeded by patents. There is no consistent evidence of a premium in testing prices attributable to patent status. Athena Diagnostics has, however, used its intellectual property to discourage other providers from offering some tests. There is no definitive answer about the suitability of current patenting and licensing of commonly tested genes because of continuing legal uncertainty about the extent of enforcement of patent rights. Clinicians have also expressed concerns that multiplex tests will be difficult to develop because of overlapping intellectual property and conflict with Athena’s sole provider business model. PMID:20393307

  19. Testing the Shock Remanent Magnetization Hypothesis at the Slate Islands Impact Structure, Canada

    NASA Astrophysics Data System (ADS)

    Tikoo, S. M.; Swanson-Hysell, N.; Fairchild, L. M.; Shuster, D. L.; Renne, P. R.

    2014-12-01

    The ubiquity of cratering events in the solar system motivates understanding how the magnetizations of planetary surfaces are affected by hypervelocity impacts. Passing shock waves may impart target rocks with shock remanent magnetization (SRM) which can, in principle, be preserved if a region does not experience substantial impact-related heating. While SRM has been proposed as an explanation for enigmatic magnetizations observed at impact craters and in extraterrestrial samples, SRM has not yet been conclusively identified in natural samples. At present, the most suggestive evidence for naturally occurring SRM exists at the ~450 Ma Slate Islands Impact Structure, Canada. The islands represent the ~10 km diameter central uplift of a ~30 km diameter complex crater. Target rocks, which consist of Archean and Paleoproterozoic dikes and metamorphic rocks as well as ~1.1 Ga dikes and lava flows, contain a pervasive impact-related secondary magnetization component which is not present in coeval rocks of corresponding lithologies outside the impact crater (Halls 1975, 1979). Our paleomagnetic study aims to determine whether the Slate Islands overprint is an SRM. Samples were collected from 18 igneous dikes and 17 lava flows across the impact structure from regions which experienced variable (2-25 GPa) shock pressures (Dressler et al., 1998). Alternating field (AF) and thermal demagnetization results indicate that the secondary component persists to AF levels reaching several tens of mT and unblocking temperatures approaching ~250-525°C. At all studied sites, grains at higher AF levels and unblocking temperatures retain pre-impact magnetizations. Secondary magnetization blocked within the lower coercivity and blocking temperature fractions of samples is consistent with an origin as either SRM or thermoviscous remanence (TVRM) resulting from impact-related heating. Viscous remanence acquired at Earth surface temperatures is precluded by the component's high unblocking temperature and distinct direction from the present local field. Comparison of natural remanent magnetization with laboratory-induced pressure and thermal remanences paired with thermochronometric and geologic constraints is being used to differentiate between the overprints originating as SRM or TVRM.

  20. Elevated Temperature Ballistic Impact Testing of PBO and Kevlar Fabrics for Application in Supersonic Jet Engine Fan Containment Systems

    NASA Technical Reports Server (NTRS)

    Pereira, J. Michael; Roberts Gary D.; Revilock, Duane M., Jr.

    1997-01-01

    Ballistic impact tests were conducted on fabric made from both Poly(phenylene benzobizoxazole) (PBO) and Kevlar 29 which were selected to be similar in weave pattern, areal density, and fiber denier. The projectiles were 2.54-cm- (1-in.-) long aluminum cylinders with a diameter of 1.27 cm (0.5 in.). The fabric specimens were clamped on four sides in a 30.5-cm- (12-in.-) square frame. Tests on PBO were conducted at room temperature and at 260 C (500 F). A number of PBO specimens were aged in air at 204 and 260 C (400 and 500 F) before impact testing. Kevlar specimens were tested only at room temperature and with no aging. The PBO absorbed significantly more energy than the Kevlar at both room and elevated temperatures. However, after aging at temperatures of 204 C (400 F) and above, the PBO fabric lost almost all of its energy absorbing ability. It was concluded that PBO fabric is not a feasible candidate for fan containment system applications in supersonic jet engines where operating temperatures exceed this level.

  1. Recent developments in the design, testing and impact-damage tolerance of stiffened composite panels

    NASA Technical Reports Server (NTRS)

    Williams, J. G.; Anderson, M. S.; Rhodes, M. D.; Starnes, J. H., Jr.; Stroud, W. J.

    1980-01-01

    The structural technology of laminated filamentary-composite stiffened-panel structures under combined in-plane and lateral loadings is discussed. Emphasis is on analyzing the behavior of the structures under load, determining appropriate structural proportions for weight efficient configurations, and effects of impact damage and geometric imperfections on structural performance. Experimental data on buckling of panels under in-plane compression validate the analysis and sizing methods, and illustrate structural performance and efficiency obtained from representative structures. It is shown that the strength of panels under in-plane compression can be degraded by low-velocity impact damage, and data are presented which indicate that the matrix is a significant factor influencing tolerance to impact damage.

  2. An Exploratory Study to Test the Impact on Three “Bolt-On” Items to the EQ-5D

    PubMed Central

    Yang, Yaling; Rowen, Donna; Brazier, John; Tsuchiya, Aki; Young, Tracey; Longworth, Louise

    2015-01-01

    Background Generic preference-based measures were criticized for being inappropriate in some conditions. One solution is to include “bolt-on” dimensions describing additional specific health problems. Objectives This study aimed to develop bolt-on dimensions to the EuroQol five-dimensional questionnaire (EQ-5D) and assess their impact on health state values. Methods Bolt-on dimensions were developed for vision problems, hearing problems, and tiredness. Each bolt-on dimension had three severity levels to match the EQ-5D. Three “core” EQ-5D states across a range of severity were selected, and each level of a bolt-on item was added, resulting in nine states in each condition. Health states with and without the bolt-on dimensions were valued by 300 members of the UK general public using time trade-off in face-to-face interviews, and mean health state values were compared using t tests. Regression analysis examined the impact of the bolt-on variants and the level of the bolt-on items after controlling for sociodemographic characteristics. Results Bolt-on dimensions had an impact on health state values of the EQ-5D; however, the size, direction, and significance of the impact depend on the severity of the core EQ-5D state and of the bolt-on dimension. Regression analysis demonstrated that after controlling for possible differences in sociodemographic characteristics between the groups, there were no significant differences in health state values between the three bolt-on dimensions but confirmed that the impact depended on the severity of the EQ-5D health state and the levels of bolt-on dimensions. Conclusions The impact of a bolt-on dimension on the EQ-5D depends on the core health state and the level of the bolt-on dimension. Further research in this area is encouraged. PMID:25595234

  3. Impact-limiting materials characterization. [Structural and thermal testing of Al honeycombs and polyurethane foams

    SciTech Connect

    Glass, R. E. [Sandia National Labs., Albuquerque, NM (United States); Duffey, T. A. [Spectra Research Inst., Albuquerque, NM (United States); McConnell, P. [GRAM, Inc., Albuquerque, NM (United States)

    1991-01-01

    Goal in the design of an impact limiter (foams or honeycombs) for packaging of radioactive materials is to minimize the deceleration loads during a drop onto an unyielding target, and to reduce the effects of a fire. Methods are being developed for selecting impact-limiting materials. Figures of merit have been developed for screening both structural and thermal response; they have been applied to aluminum honeycombs and polyurethane foams. Three figures of merit are presented for the structural response, one figure for the thermal response (minimize the heat flux into the containment boundary). 11 figs., 6 refs. (DLC)

  4. Testing three health impact assessment tools in planning: A process evaluation

    SciTech Connect

    Schively Slotterback, Carissa, E-mail: cschively@umn.ed [University of Minnesota, Humphrey Institute of Public Affairs, 130 HHH Center, 301 19th Ave. S., Minneapolis, MN 55455 (United States); Forsyth, Ann, E-mail: Forsyth@cornell.ed [Cornell University (United States); Krizek, Kevin J., E-mail: krizek@colorado.ed [University of Colorado (United States); Johnson, Amanda, E-mail: gama@design.upenn.ed [University of Pennsylvania (United States); Pennucci, Aly, E-mail: aly.pennucci@ci.minneapolis.mn.u [City of Minneapolis (United States)

    2011-03-15

    There is increasing interest in Health Impact Assessment in planning. This paper describes the results of different approaches to health impact assessment (HIA) conducted in 10 municipalities and one county in Minnesota. The paper outlines the HIA processes, outputs, and short-term outcomes concluding that it is important to engage a diverse group of stakeholders. Overall, HIA is potentially an important new tool in the planning toolkit. Strategic use of HIA to evaluate draft plans and inform plan updates and project redesigns can help raise awareness about health issues and focus planning on important human problems.

  5. A terrestrial ecotoxicological test: Impact of pollutants on plant -- Insect interactions

    SciTech Connect

    Kjaer, C.; Elmegaard, N. [National Environmental Research Inst., Silkeborg (Denmark). Dept. of Terrestrial Ecology

    1994-12-31

    Single species toxicity tests are often criticized or doubted due to a lack of confidence in their predictive power. Single species tests cannot detect changes of interactions between species due to a pollutant. One aim of the presented project is to study what kind of new information is gained from a two species laboratory test system compared to single species test conducted with the same two species. The species used are the annual weed Polygonum convolvulus L and the leaf beetle Gastrophysa polygoni. Data from experiments with a herbicide (chlorsulfuron), a insecticide (dimethoate) and copper are presented. Compared to single species tests, the two species test not only provide dose-response data on the interactions between species, it also represents a more realistic exposure route and corn rises more complexity still being reproducible.

  6. Impact of a standardized test package on exit examination scores and NCLEX-RN outcomes.

    PubMed

    Homard, Catherine M

    2013-03-01

    The purpose of this ex post facto correlational study was to compare exit examination scores and NCLEX-RN(®) pass rates of baccalaureate nursing students who differed in level of participation in a standardized test package. Three cohort groups emerged as a standardized test package was introduced: (a) students who did not participate in a standardized test package; (b) students with two semesters of a standardized test package; and (c) students with four semesters of a standardized test package. Benner's novice-to-expert theory framed the study in the belief that students best acquire knowledge and skills through practice and reflection. Students participating in four semesters of a standardized test package demonstrated higher exit examination scores and NCLEX-RN pass rates compared with students who did not participate in this package. This study's results could inform nurse educators about strategies to facilitate nursing student success on exit examinations and the NCLEX-RN. PMID:23413805

  7. On the utilization of the instrumented Charpy impact test for characterizing the flow and fracture behavior of reactor pressure vessel steels

    Microsoft Academic Search

    R. Chaouadi; A. Fabry

    2002-01-01

    The Charpy impact test is extensively used in the surveillance programs to monitor neutron reactor pressure vessel degradation induced by neutron irradiation. The energy absorbed during the test is the main parameter used for engineering characterization of thematerials. At SCK·CEN, a large effort was put into taking advantage of the test instrumentation allowing for load versus time recording during the

  8. Ecological Impacts of Large–Scale War Preparations: Semipalatinsk Test Site, Kazakhstan

    Microsoft Academic Search

    Mukhambetkali Burkitbayev; Nicholas Priest; Peter Mitchell; Leon Vintro; Laurent Pourcelot; Yelena Kuyanova; Oleg Artemyev

    \\u000a Development and testing of weapons of mass destruction may result in irreversible environmental changes resulting in high\\u000a social risk and negative effects on human health. The former Semipalatinsk nuclear test site (STS) is a sorrowful monument\\u000a of the Cold War. Nuclear tests at STS inflicted numerous economic, social and ecological problems on Kazakhstan. In the framework\\u000a of the NATO “Science

  9. Psychological impact of genetic testing in women from high-risk breast cancer families

    Microsoft Academic Search

    B Meiser; P Butow; M Friedlander; A Barratt; V Schnieden; M Watson; J Brown; K Tucker

    2002-01-01

    Psychological adjustment in 90 women (30 carriers and 60 non-carriers) who had undergone genetic testing for mutations in BRCA1 and BRCA2 breast\\/ovarian cancer susceptibility genes was compared with that of 53 women who were not offered genetic testing. Women were assessed prior to genetic testing and 7–10 days, 4 and 12 months after carrier status disclosure using self-administered questionnaires. Compared

  10. Evaluating the Impact of Test-and-Treat on the HIV Epidemic among MSM in China Using a Mathematical Model

    PubMed Central

    Lu, Hongyan; Dou, Zhi; Tao, Qian; Khoshnood, Kaveh; Wu, Zunyou; Xu, Jie

    2015-01-01

    Background Various studies have modeled the impact of test-and-treat policies on the HIV epidemics worldwide. However, few modeling studies have taken into account China’s context. To understand the potential effect of test-and-treat on the HIV epidemic among men who have sex with men (MSM) in China, we developed a mathematical model to evaluate the impact of the strategy. Method Based on the natural history of the CD4 count of people living with HIV and AIDS (PLWHA), we constructed a dynamic compartmental model of HIV transmission among Chinese MSM to project the number of HIV new infections and prevalence over 10 years. We predicted the annual number of HIV new infections and the total number of MSM living with HIV and AIDS (based on Beijing data) between 2010 and 2022 under the following conditions: (1) current practice (testing rate of 50% and ART coverage of 39%); (2) both testing rate and ART coverage increasing to 70% in 2013; (3) both testing rate and ART coverage increasing to 90% in 2013; and (4) both testing rate and ART coverage increasing gradually every year until 90% since 2013. Results Based on our model, if the HIV test-and-treat policy was implemented among Chinese MSM, the total number of HIV new infections over 10 years (2013-2022) would be reduced by 50.6-70.9% compared with the current policy. When ART coverage for PLWHA increased to 58% since 2013, the ‘turning point’ would occur on the curve of HIV new infections by 2015. A 25% reduction in annual number of HIV new infections by 2015 might be achieved if the testing rate increased from 50% to 70% and treatment coverage for PLWHA increased to 55% since 2013. Conclusion Implementation of the test-and-treat strategy may significantly reduce HIV new infections among MSM in China. Great efforts need to be made to scale up HIV testing rate and ART coverage among Chinese MSM. PMID:26039075

  11. Prostate-Specific Antigen Testing in Men Aged 40–64 Years: Impact of Publication of Clinical Trials

    PubMed Central

    2013-01-01

    We assessed the impact of the publication of trials and changes in recommendations on the rates of prostate-specific antigen (PSA) screening in men aged 40 to 64 years by analyzing monthly medical claims for PSA testing in a commercial insurance database from 2001 to 2011, covering more than 1.5 million men in each year. The testing rates for men aged 40 to 49 years, 50 to 59 years, and 60 to 64 years were 12.1%, 32.7%, and 42.7%, respectively, in 2001 vs 15.7%, 34.2%, and 42.0%, respectively, in 2011. Men aged 40 to 49 years experienced a gradual increase in testing rate from 2001 through 2008 (annual change in PSA testing per 10 000 men [AC] = 4.37; P < .001), which became flat from mid-2009 through 2011(AC = ?0.06; P =.98). The slope of PSA testing rates did not change in men aged 50 to 59 years or 60 to 64 years with the publication of the results of the large trials in 2009 or with the subsequent changes in recommendations on PSA testing. PMID:23459245

  12. Effect of projectile hardness on deformation and fracture behavior in the Taylor impact test

    Microsoft Academic Search

    Xinke Xiao; Wei Zhang; Gang Wei; Zhongcheng Mu

    2010-01-01

    The ballistic perforation performance of a kinetic energy projectile would be much more influenced by the projectile’s deformation during the impact process. A projectile may suffer from large deformation and even fracture as more and more advanced materials are used as resistant components. A comparison investigation was presented in this study concerning the deformation and fracture behavior of kinetic energy

  13. Out-of-School Time Program Test Score Impact for Black Children of Single-Parents

    ERIC Educational Resources Information Center

    Nagle, Barry T.

    2013-01-01

    Out-of-School Time programs and their impact on standardized college entrance exam scores for black or African-American children of single parents who have applied for a competitive college scholarship program is the study focus. Study importance is supported by the large percentage of black children raised by single parents, the large percentage…

  14. Impact of HFE genetic testing on clinical presentation of hereditary hemochromatosis: new epidemiological data

    Microsoft Academic Search

    Virginie Scotet; Gérald Le Gac; Marie-Christine Mérour; Anne-Yvonne Mercier; Brigitte Chanu; Chandran Ka; Catherine Mura; Jean-Baptiste Nousbaum; Claude Férec

    2005-01-01

    BACKGROUND: Hereditary hemochromatosis (HH) is a common inherited disorder of iron metabolism in Northern European populations. The discovery of a candidate gene in 1996 (HFE), and of its main mutation (C282Y), has radically altered the way to diagnose this disease. The aim of this study was to assess the impact of the HFE gene discovery on the clinical presentation and

  15. Conclusions from the ASTM interlaboratory test program with liquid impact erosion facilities

    Microsoft Academic Search

    F. J. Heymann

    1979-01-01

    An evaluation of data from the ASTM interlaboratory program on liquid impingement erosion is presented. It was found that: (1) erosion data should be in a logarithmic form for statistical analyses; (2) results are appropriately expressed in terms of volumetric 'rationalized erosion rate' and 'number of specific impacts' for incubation; (3) the normalized 'erosion resistance' and 'incubation resistance' values were

  16. The impact of customer relationship management capability on innovation and performance advantages: testing a mediated model

    Microsoft Academic Search

    Moustafa Battor; Mohamed Battor

    2010-01-01

    Customer relationship management (CRM) and innovation are widely considered to be valuable capabilities associated with competitive advantage. However, there is a lack of research demonstrating how they work together to produce performance advantages. This research investigates the mediating role of innovation between CRM and performance. The authors examine the direct impact of both CRM and innovation on firm performance. Moreover,

  17. An analysis of the forces and bending moments generated during the notched beam impact test

    Microsoft Academic Search

    Gerald E. Nash

    1969-01-01

    An analysis is presented which predicts the hammer force and specimen bending moment-time responses during impact from the dynamics of the system and the fracture characteristics of the material. The theoretical predictions are compared to available experimental observations and good agreement is obtained for brittle materials.

  18. Drop Weight Impact Test Fracture of Vinyl Ester Composites: Micrographs of Pilot Study

    Microsoft Academic Search

    H. Ku; Y. M. Cheng; C. Snook; D. Baddeley

    2005-01-01

    The shrinkage of vinyl ester particulate composites has been reduced by curing the resins under microwave conditions. The reduction in the shrinkage of the resins by microwaves will enable the manufacture of large vinyl ester composite items possible [12-15]. This project is to investigate the difference in impact strength between microwave cured vinyl ester particulate composites and those cured under

  19. DWPF (Defense Waste Processing Facility) canister impact testing and analyses for the Transportation Technology Center

    Microsoft Academic Search

    R. K. Farnsworth; J. Mishima

    1988-01-01

    A legal weight truck cask design has been developed for the US Department of Energy by GA Technologies, Inc. The cask will be used to transport defense high-level waste canisters produced by the Defense Waste Processing Facility (DWPF) at the Savannah River Plant. The development of the cask required the collection of impact data for the DWPF canisters. The Materials

  20. Testing GPS L5 Tracking Algorithms and their Impact on Positioning Accuracy

    Microsoft Academic Search

    C. Mongrédien; G. Lachapelle; M. E. Cannon

    The performances of several GPS L5 tracking implementations are evaluated using IF samples obta ined with a hardware simulator. The aim of this study is to assess how the data\\/pilot implementation used for t he GPS L5 signal impacts the performance of various tracking implementations, and how these tracking performance variations translate into the position domain. In particular, the Kalman

  1. Author's personal copy Paleomagnetism of impact spherules from Lonar crater, India and a test for

    E-print Network

    Weiss, Benjamin P.

    , Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology 54-814, 77 Massachusetts Ave paleointensity impact-generated fields Moon Mars asteroids Planetary surfaces have been ubiquitously melted igneous samples from rocky bodies like the Moon, Mars, and asteroids. Upon cooling, these melts may record

  2. Environmental impact assessment of tailings dispersal from a uranium mine using toxicity testing protocols

    Microsoft Academic Search

    G. D. Rippon; S. J. Riley

    1996-01-01

    Toxicity testing is a means of establishing the environmental risk of uranium tailings release. It is valuable in designing tailings containment structures because it assists in setting acceptable levels of risk of the design. This paper presents details of toxicity tests of the tailings from Ranger Uranium Mine, Northern Territory, Australia. The results suggest that the non-radiological toxicity of the

  3. India's Changing Policy on Space Militarization: The Impact of China's ASAT Test

    Microsoft Academic Search

    Rajeswari Pillai Rajagopalan

    2011-01-01

    China's anti-satellite (ASAT) test of January 2007 has brought renewed focus on space security. The test also appears to have forced a re-evaluation of India's traditional declaratory policy against the militarization of space and more specifically created pressures for an Indian ASAT system. India's policy itself does not appear to have fully changed yet but there are signs of some

  4. Exploring the Impact of Cumulative Testing on Academic Performance of Undergraduate Students in Spain

    ERIC Educational Resources Information Center

    Domenech, Josep; Blazquez, Desamparados; de la Poza, Elena; Mun?oz-Miquel, Ana

    2015-01-01

    Frequent testing provides opportunities for students to receive regular feedback and to increase their motivation. It also provides the instructor with valuable information on how course progresses, thus making it possible to solve the problems encountered before it is too late. Frequent tests with noncumulative contents have been widely analysed…

  5. Testing Report: Littleford-Day Dryer Operation: Dryer Operation Impacts of Proposed MIS Mitigation Changes

    SciTech Connect

    Shimskey, Rick W.; Buchmiller, William C.; Elmore, Monte R.

    2007-06-01

    Pacific Northwest National Laboratory performed a series of tests using the Littleford Day 22-liter dryer during investigations that evaluated changes in the melter-feed composition for the Demonstration Bulk Vitrification System. During testing, a new melter-feed formulation was developed that improved dryer performance while improving the retention of waste salts in the melter feed during vitrification.

  6. Impact of Gene Patents and Licensing Practices on Access to Genetic Testing for Hereditary Hemochromatosis

    PubMed Central

    Chandrasekharan, Subhashini; Pitlick, Emily; Heaney, Christopher; Cook-Deegan, Robert

    2010-01-01

    Hereditary hemochromatosis (HH) is an iron metabolism disorder that leads to excess iron buildup, especially in the heart, liver, and pancreas. Mutations in the HFE gene are the single most common cause of HH, which can be treated effectively if diagnosed early. Patents cover the HFE gene, related proteins, screening methods, and testing kits. Most initial testing for HH is biochemical, but HFE DNA testing or genotyping is used to confirm a diagnosis of inherited hemochromatosis. Concerns over patents covering HFE testing emerged in 2002, when scholars argued that exclusive licensing and the patent-enabled sole provider model then in place led to high prices and limited access. Critics of the sole provider model noted that the test was available at multiple laboratories prior to the enforcement of patents. By 2007, however, Bio-Rad, Limited, acquired the key intellectual property and sub-licensed it widely. In part because of broad, non-exclusive licensing, there are now multiple providers and testing technologies, and research continues. This case study illustrates how both changes in intellectual property ownership and evolving clinical utility of HFE genetic testing in the last decade have effected the licensing of patents and availability of genetic testing. PMID:20393306

  7. ACT Test Preparation Course and Its Impact on Students' College- and Career-Readiness

    ERIC Educational Resources Information Center

    Parrott, Timothy Nolan

    2012-01-01

    This study examined the effectiveness of an ACT intervention course developed for high school juniors at Anderson County High School during the 2011-2012 school year. This study compared the ACT composite test scores of the treatment group to the ACT composite test scores of the control group by using their PLAN scores as a baseline, to determine…

  8. Reducing the Impact of Inappropriate Items on Reviewable Computerized Adaptive Testing

    ERIC Educational Resources Information Center

    Yen, Yung-Chin; Ho, Rong-Guey; Liao, Wen-Wei; Chen, Li-Ju

    2012-01-01

    In a test, the testing score would be closer to examinee's actual ability when careless mistakes were corrected. In CAT, however, changing the answer of one item in CAT might cause the following items no longer appropriate for estimating the examinee's ability. These inappropriate items in a reviewable CAT might in turn introduce bias in ability…

  9. Fairness in Computerized Testing: Detecting Item Bias Using CATSIB with Impact Present

    ERIC Educational Resources Information Center

    Chu, Man-Wai; Lai, Hollis

    2013-01-01

    In educational assessment, there is an increasing demand for tailoring assessments to individual examinees through computer adaptive tests (CAT). As such, it is particularly important to investigate the fairness of these adaptive testing processes, which require the investigation of differential item function (DIF) to yield information about item…

  10. Axial focusing of impact energy in the Earth's interior: Proof-of-principle tests of a new hypothesis

    NASA Technical Reports Server (NTRS)

    Boslough, M. B.; Chael, E. P.; Trucano, T. G.; Kipp, M. E.; Crawford, D. A.

    1994-01-01

    A causal link between major impact events and global processes would probably require a significant change in the thermal state of the Earth's interior, presumably brought about by coupling of impact energy. One possible mechanism for such energy coupling from the surface to the deep interior would be through focusing due to axial symmetry. Antipodal focusing of surface and body waves from earthquakes is a well-known phenomenon which has previously been exploited by seismologists in studies of the Earth's deep interior. Antipodal focusing from impacts on the Moon, Mercury, and icy satellites has also been invoked by planetary scientists to explain unusual surface features opposite some of the large impact structures on these bodies. For example, 'disrupted' terrains have been observed antipodal to the Caloris impact basis on Mercury and Imbrium Basin on the Moon. Very recently there have been speculations that antipodal focusing of impact energy within the mantle may lead to flood basalt and hotspot activity, but there has not yet been an attempt at a rigorous model. A new hypothesis was proposed and preliminary proof-of-principle tests for the coupling of energy from major impacts to the mantle by axial focusing of seismic waves was performed. Because of the axial symmetry of the explosive source, the phases and amplitudes are dependent only on ray parameter (or takeoff angle) and are independent of azimuthal angle. For a symmetric and homogeneous Earth, all the seismic energy radiated by the impact at a given takeoff angle will be refocused (minus attenuation) on the axis of symmetry, regardless of the number of reflections and refractions it has experienced. Mantle material near the axis of symmetry will experience more strain cycles with much greater amplitude than elsewhere and will therefore experience more irreversible heating. The situation is very different than for a giant earthquake, which in addition to having less energy, has an asymmetric focal mechanism and a larger area. Two independent proof-of-principle approaches were used. The first makes use of seismic simulations, which are being performed with a realistic Earth model to determine the degree of focusing along the axis and to estimate the volume of material, if any, that experiences significant irreversible heating. The second involves two-dimensional hydrodynamic code simulations to determine the stress history, internal energy, and temperature rise as a function of radius along the axis.

  11. Department of Physics' Involvement of the Impact Testing Project of the High Speed Civil Transport Program (HSCT)

    NASA Technical Reports Server (NTRS)

    VonMeerwall, Ernst D.

    1994-01-01

    The project involved the impact testing of a kevlar-like woven polymer material, PBO. The purpose was to determine whether this material showed any promise as a lightweight replacement material for jet engine fan containment. The currently used metal fan containment designs carry a high drag penalty due to their weight. Projectiles were fired at samples of PBO by means of a 0.5 inch diameter Helium powered gun. The Initial plan was to encase the samples inside a purpose-built steel "hot box" for heating and ricochet containment. The research associate's responsibility was to develop the data acquisition programs and techniques necessary to determine accurately the impacting projectile's velocity. Beyond this, the Research Associate's duties include any physical computations, experimental design, and data analysis necessary.

  12. Evaluation of the Biorid P3 and the Hybrid III in Pendulum Impacts to the Back - A Comparison to Human Subject Test Data

    PubMed Central

    Linder, Astrid; Bergman, Ulf; Svensson, Mats; Viano, David

    2000-01-01

    The BioRID P3 (Biofidelic Rear Impact Dummy) and the Hybrid III were evaluated in pendulum impacts to the back and compared to data from previous cadaver tests. The test setup impacting seated cadavers was reproduced with a pendulum impacting seated dummies at the level of T6 (6th thoracic vertebra). The pendulum mass was 23 kg and the impact velocity 4.6 m/s. The results showed that the BioRID P3 was more biofidelic than the Hybrid III in terms of the peak responses and the temporal window of the head and head relative to T1 horizontal, vertical, and angular displacement. This study is an evaluation of both the BioRID P3 and the Hybrid III against a recently available set of human subject data. The study meets the need for validation of the BioRID P3 at a higher impact severity than has been previously accomplished. PMID:11558088

  13. Ground based impact testing of Orbiter thermal protection system materials in support of the Columbia accident investigation

    NASA Astrophysics Data System (ADS)

    Kerr, Justin Hamilton

    On January 16, 2003, the Space Shuttle Columbia (OV-102) was launched for a nominal 16-day mission of microgravity research. Fifteen days and 20 hours after launch, and just 16 minutes before its scheduled landing, the OV-102 vehicle disintegrated during its descent. The entire crew was lost. Film and video cameras located around the launch complex captured images of the vehicle during its ascent. Of note were data that showed a piece of debris strike the port wing at approximately 82 sec after lift-off (T+82). As resulting analysis would show, the source of the debris was the left bipod ramp of the Shuttle external tank. This foam debris struck the Orbiter leading edge at sufficient velocity to breech the thermal protection system (TPS). During reentry at the end of the mission, the hot plasma impinged inside the Orbiter wing and aerodynamic forces ultimately failed the wing structure. This thesis documents the activities conducted to evaluate the effects of foam impact on Orbiter TPS. These efforts were focused on, to the greatest extent practical, replicating the impact event during the STS-107 mission ascent. This thesis fully documents the test program development, methodology, results, analysis, and conclusions to the degree that future investigators can reproduce the tests and understand the basis for decisions made during the development of the tests.

  14. Strain energy density as a rupture criterion for the kidney: impact tests on porcine organs, finite element simulation, and a baseline comparison between human and porcine tissues

    Microsoft Academic Search

    J. G. Snedeker; M. Barbezat; P. Niederer; F. R. Schmidlin; M. Farshad

    2005-01-01

    High-velocity (up to 25m\\/s) impact tests were performed on pig kidneys to characterize failure behavior at deformation rates associated with traumatic injury. Cylindrical tissue samples (n=45) and whole perfused organs (n=34) were impacted using both falling weights and a high-velocity pneumatic projectile impactor. Impact energy was incrementally increased until visible rupture occurred. The strain energy density failure threshold fell between

  15. Analysis of the 2007 Chinese ASAT Test and the Impact of its Debris on the Space Environment

    NASA Astrophysics Data System (ADS)

    Kelso, T.

    On 2007 January 11, the People's Republic of China conducted a successful direct-ascent ASAT test against one of their own defunct polar-orbiting weather satellites. The test produced at least 1,337 pieces of debris large enough to be routinely tracked by the US Space Surveillance Network and the NASA Orbital Debris Program Office estimated it generated over 35,000 pieces of debris down to 1 centimeter in size. While this event captured worldwide attention in the weeks and months after the test was revealed, much of the information provided in the press was inaccurate or misleading and did not appear to be based on scientific analysis of the data available to the public. In order to help the public and key policy makers more fully understand the nature of the event and its impact on the existing satellite population, the Center for Space Standards & Innovation developed a series of animations, images, and graphical analyses to more clearly portray this event and provide a factual foundation for the subsequent debate. Those materials were all made publicly available via the Internet without restriction and have appeared in numerous publications. This paper will summarize the primary areas of analysis of this event, to include a confirmation of the basic facts initially reported in Aviation Week & Space Technology, a visualization of the initial spread of the debris cloud in the first couple of hours after the attack, analysis of the impact of the debris on the LEO space environment including the number of satellites potentially affected and the increase in the number of conjunctions, a look at the current debris environment, and an assessment of the orbital lifetimes that shows that these impacts will last not for years but for centuries. The visualization techniques used to portray these analyses played a substantial role in helping the scientific community to quickly and easily convey important aspects of this event to policy makers and the public at large.

  16. Recent development in the design, testing and impact-damage tolerance of stiffened composite panels

    NASA Technical Reports Server (NTRS)

    Williams, J. G.; Anderson, M. S.; Rhodes, M. D.; Starnes, J. H., Jr.; Stroud, W. J.

    1979-01-01

    Structural technology of laminated filamentary-composite stiffened-panel structures under combined inplane and lateral loadings is discussed. Attention is focused on: (1) methods for analyzing the behavior of these structures under load and for determining appropriate structural proportions for weight-efficient configurations; and (2) effects of impact damage and geometric imperfections on structural performance. Recent improvements in buckling analysis involving combined inplane compression and shear loadings and transverse shear deformations are presented. A computer code is described for proportioning or sizing laminate layers and cross-sectional dimensions, and the code is used to develop structural efficiency data for a variety of configurations, loading conditions, and constraint conditions. Experimental data on buckling of panels under inplane compression is presented. Mechanisms of impact damage initiation and propagation are described.

  17. Fibre optic sensors for high speed hypervelocity impact studies and low velocity drop tests

    Microsoft Academic Search

    D. A. Jackson; M. J. Cole; M. J. Burchell; D. J. Webb

    2011-01-01

    The initial aim of this project was to develop a non-contact fibre optic based displacement sensor to operate in the harsh environment of a 'Light Gas Gun' (LGG), which can 'fire' small particles at velocities ranging from 1-8.4 km\\/s. The LGG is used extensively for research in aerospace to analyze the effects of high speed impacts on materials. Ideally the

  18. A test of a mechanical multi-impact shear-wave seismic source

    USGS Publications Warehouse

    Worley, David M.; Odum, Jack K.; Williams, Robert A.; Stephenson, William J.

    2001-01-01

    We modified two gasoline-engine-powered earth tampers, commonly used as compressional-(P) wave seismic energy sources for shallow reflection studies, for use as shear(S)-wave energy sources. This new configuration, termed ?Hacker? (horizontal Wacker?), is evaluated as an alternative to the manual sledgehammer typically used in conjunction with a large timber held down by the front wheels of a vehicle. The Hacker maximizes the use of existing equipment by a quick changeover of bolt-on accessories as opposed to the handling of a separate source, and is intended to improve the depth of penetration of S-wave data by stacking hundreds of impacts over a two to three minute period. Records were made with a variety of configurations involving up to two Hackers simultaneously then compared to a reference record made with a sledgehammer. Preliminary results indicate moderate success by the higher amplitude S-waves recorded with the Hacker as compared to the hammer method. False triggers generated by the backswing of the Hacker add unwanted noise and we are currently working to modify the device to eliminate this effect. Correlation noise caused by insufficient randomness of the Hacker impact sequence is also a significant noise problem that we hope to reduce by improving the coupling of the Hacker to the timber so that the operator has more control over the impact sequence.

  19. Impact of Instructional Sensitivity on High-Stakes Achievement Test Items: A Comparison of Methods

    E-print Network

    Chen, Jie

    2012-08-31

    theme of the No Child Left Behind Act (NCLB) is accountability, including accountability through adequate yearly progress (AYP) (Simpson, LaCava & Graner, 2004). An appropriate NCLB test should be instructionally sensitive, meaning it has the capacity...

  20. The Impact of Structure on Word Meaning and Fill-in-The-Blank Tests Procedures on Short-Term and Long-Term Retention of Vocabulary Items

    ERIC Educational Resources Information Center

    Fazeli, Seyed Hossein

    2009-01-01

    The purpose of research described in the current study to investigate the impact of structure knowing on two types of test, i.e. word-meaning test and fill-in-the-blank test, their correlation and procedures on both short-term and long-term retention of vocabulary items. The importance of the present study, to test the condition that learners are…

  1. Cost Impact of Molecular Testing for Indeterminate Thyroid Nodule Fine-Needle Aspiration Biopsies

    PubMed Central

    Farris, Coreen; Kabaker, Adam S.; Hodak, Steven P.; Nikiforova, Marina N.; McCoy, Kelly L.; Stang, Michael T.; Smith, Kenneth J.; Nikiforov, Yuri E.; Carty, Sally E.

    2012-01-01

    Introduction: Molecular testing of fine-needle aspiration (FNA) results helps diagnose thyroid cancer, although the additional cost of this adjunct has not been studied. We hypothesized that FNA molecular testing of two indeterminate categories (follicular lesion of undetermined significance and follicular/Hürthle cell neoplasm) can be cost saving. Methods: For a hypothetical group of euthyroid patients with a 1-cm or larger solitary thyroid nodule, a decision-tree model was constructed to compare the estimated costs of initial evaluation according to the current American Thyroid Association guidelines, either with molecular testing (MT) or without [standard of care (StC)]. Model endpoints were either benign FNA results or definitive histological diagnosis. Results: Molecular testing added $104 per patient to the overall cost of nodule evaluation (StC $578 vs. MT $682). In this distributed cost model, MT was associated with a decrease in the number of diagnostic lobectomies (9.7% vs. StC 11.6%), whereas initial total thyroidectomy was more frequent (18.2% vs. StC 16.1%). Although MT use added a diagnostic cost of $5031 to each additional indicated total thyroidectomy ($11,383), the cumulative cost was still less than the comparable cost of performing lobectomy ($7684) followed by completion thyroidectomy ($11,954) in the StC pathway, when indicated by histological results. In sensitivity analysis, savings were demonstrated if molecular testing cost was less than $870. Conclusions: Molecular testing of cytologically indeterminate FNA results is cost saving predominantly because of reduction in two-stage thyroidectomy. Appropriate use of emerging molecular testing techniques may thus help optimize patient care, improve resource use, and avoid unnecessary operation. PMID:22419727

  2. Evaluation of impact limiter performance during end-on and slapdown drop tests of a one-third scale model storage/transport cask system

    SciTech Connect

    Yoshimura, H.R.; Bronowski, D.R.; Uncapher, W.L.; Attaway, S.W.; Bateman, V.I.; Carne, T.G.; Gregory, D.L. (Sandia National Labs., Albuquerque, NM (USA)); Huerta, M. (Southwest Engineering Associates, El Paso, TX (USA))

    1990-12-01

    This report describes drop testing of a one-third scale model shipping cask system. Two casks were designed and fabricated by Transnuclear, Inc., to ship spent fuel from the former Nuclear Fuel Services West Valley reprocessing facility in New York to the Idaho National Engineering Laboratory for a long-term spent fuel dry storage demonstration project. As part of the NRC's regulatory certification process, one-third scale model tests were performed to obtain experimental data on impact limiter performance during impact testing. The objectives of the testing program were to (1) obtain deceleration and displacement information for the cask and impact limiter system, (2) obtain dynamic force-displacement data for the impact limiters, (3) verify the integrity of the impact limiter retention system, and (4) examine the crush behavior of the limiters. Two 30-ft (9-m) drop tests were conducted on a mass model of the cask body and scaled balsa and redwood-filled impact limiters. This report describes the results of both tests in terms of measured decelerations, posttest deformation measurements, and the general structural response of the system. 3 refs., 32 figs.

  3. Test of developing long-term forecasts of world energy impact on the earth's atmosphere

    NASA Astrophysics Data System (ADS)

    Klimenko, V. V.; Klimenko, A. V.; Tereshin, A. G.

    2015-03-01

    It has been established that the historical approach to world energy forecasting can yield useful results at time horizons with a depth of several decades. The genetic forecast supposes reaching a plateau of global energy consumption at the level of 30 billion tons of coal equivalent and an increase in the carbon dioxide concentration almost to 500 parts per million by the end of the century against the background of a continuing decrease in sulfur dioxide emission. From the historical point of view, the implementation of the most aggressive scenarios of human impact on the atmosphere and climate seems very unlikely.

  4. Testing neutrino magnetic moment in ionization of atoms by neutrino impact

    E-print Network

    K. A. Kouzakov; A. I. Studenikin; M. B. Voloshin

    2011-05-27

    The atomic ionization processes induced by scattering of neutrinos play key roles in the experimental searches for a neutrino magnetic moment. Current experiments with reactor (anti)neutrinos employ germanium detectors having energy threshold comparable to typical binding energies of atomic electrons, which fact must be taken into account in the interpretation of the data. Our theoretical analysis shows that the so-called stepping approximation to the neutrino-impact ionization is well applicable for the lowest bound Coulomb states, and it becomes exact in the semiclassical limit. Numerical evidence is presented using the Thomas-Fermi model for the germanium atom.

  5. Instrumented Taylor anvil-on-rod impact tests for validating applicability of standard strength models to transient deformation states

    NASA Astrophysics Data System (ADS)

    Eakins, D. E.; Thadhani, N. N.

    2006-10-01

    Instrumented Taylor anvil-on-rod impact tests have been conducted on oxygen-free electronic copper to validate the accuracy of current strength models for predicting transient states during dynamic deformation events. The experiments coupled the use of high-speed digital photography to record the transient deformation states and laser interferometry to monitor the sample back (free surface) velocity as a measure of the elastic/plastic wave propagation through the sample length. Numerical continuum dynamics simulations of the impact and plastic wave propagation employing the Johnson-Cook [Proceedings of the Seventh International Symposium on Ballistics, 1983, The Netherlands (Am. Def. Prep. Assoc. (ADPA)), pp. 541-547], Zerilli-Armstrong [J. Appl. Phys. C1, 1816 (1987)], and Steinberg-Guinan [J. Appl. Phys. 51, 1498 (1980)] constitutive equations were used to generate transient deformation profiles and the free surface velocity traces. While these simulations showed good correlation with the measured free surface velocity traces and the final deformed sample shape, varying degrees of deviations were observed between the photographed and calculated specimen profiles at intermediate deformation states. The results illustrate the usefulness of the instrumented Taylor anvil-on-rod impact technique for validating constitutive equations that can describe the path-dependent deformation response and can therefore predict the transient and final deformation states.

  6. FAA Development of Reliable Modeling Methodologies for Fan Blade Out Containment Analysis. Part 2; Ballistic Impact Testing

    NASA Technical Reports Server (NTRS)

    Revilock, Duane M.; Pereira, J. Michael

    2008-01-01

    This report summarizes the ballistic impact testing that was conducted to provide validation data for the development of numerical models of blade out events in fabric containment systems. The ballistic impact response of two different fiber materials - Kevlar 49 (E.I. DuPont Nemours and Company) and Zylon AS (Toyobo Co., Ltd.) was studied by firing metal projectiles into dry woven fabric specimens using a gas gun. The shape, mass, orientation and velocity of the projectile were varied and recorded. In most cases the tests were designed such that the projectile would perforate the specimen, allowing measurement of the energy absorbed by the fabric. The results for both Zylon and Kevlar presented here represent a useful set of data for the purposes of establishing and validating numerical models for predicting the response of fabrics under conditions simulating those of a jet engine blade release situations. In addition some useful empirical observations were made regarding the effects of projectile orientation and the relative performance of the different materials.

  7. Evaluation of the Clinical Impact of ISO 4049 in Comparison with Miniflexural Test on Mechanical Performances of Resin Based Composite

    PubMed Central

    Calabrese, Luigi; Fabiano, Francesca; Bonaccorsi, Lucio Maria; Fabiano, Valerio; Borsellino, Chiara

    2015-01-01

    The aim of this study was to evaluate the effect of different specimens dimensions on the mechanical properties of a commercial microfilled resin composite by using a modified ISO 4049 standard protocol, that generally provides specimen dimensions of 25?mm length × 2?mm width × 2?mm height; these standard dimensions are not clinically realistic considering the teeth diameter and length average. Furthermore, the overlapping irradiations required lead to specimens that are not homogeneous with the presence of some flaws due to packaging steps. For this reason, a miniflexural test was employed in this work both to simulate clinically realistic dimensions and to concentrate fewer defects. The flexural tests were performed at varying span length, in the range between 18.5?mm as stated by the ISO 4049 flexural test (IFT) and 10.5?mm according to the miniflexural test (MFT), at the increasing of layers with a 1?mm buildup multilayering technique. The results evidenced the impact of specimen dimensions on mechanical performances and consequently stability of resin-based composite with the formation of an asymmetrical structure which possesses higher stiffness and strength at increasing layering steps. PMID:25815011

  8. Evaluation of the Clinical Impact of ISO 4049 in Comparison with Miniflexural Test on Mechanical Performances of Resin Based Composite.

    PubMed

    Calabrese, Luigi; Fabiano, Francesca; Bonaccorsi, Lucio Maria; Fabiano, Valerio; Borsellino, Chiara

    2015-01-01

    The aim of this study was to evaluate the effect of different specimens dimensions on the mechanical properties of a commercial microfilled resin composite by using a modified ISO 4049 standard protocol, that generally provides specimen dimensions of 25?mm length × 2?mm width × 2?mm height; these standard dimensions are not clinically realistic considering the teeth diameter and length average. Furthermore, the overlapping irradiations required lead to specimens that are not homogeneous with the presence of some flaws due to packaging steps. For this reason, a miniflexural test was employed in this work both to simulate clinically realistic dimensions and to concentrate fewer defects. The flexural tests were performed at varying span length, in the range between 18.5?mm as stated by the ISO 4049 flexural test (IFT) and 10.5?mm according to the miniflexural test (MFT), at the increasing of layers with a 1?mm buildup multilayering technique. The results evidenced the impact of specimen dimensions on mechanical performances and consequently stability of resin-based composite with the formation of an asymmetrical structure which possesses higher stiffness and strength at increasing layering steps. PMID:25815011

  9. Acute and sublethal toxicity tests to monitor the impact of leachate on an aquatic environment.

    PubMed

    Bloor, M C; Banks, C J; Krivtsov, V

    2005-02-01

    In this study, a specific landfill leachate (1200 mg l(-1) COD and 600 mg l(-1) BOD(5)) was used to develop a standardised short-term acute and longer-term sublethal ex-situ toxicity testing programme, in order to determine the potential ecological implications of leaching contaminants reaching the water table. Bioassays were undertaken with juvenile Gammarus pulex and Asellus aquaticus macro-invertebrates. Preliminary acute test variables included static and static renewed flow rates for 96-h, starved and fed specimens, and aerobic and oxygen depleting conditions. However, regardless of any test variable, the lethal concentration (LC(50)) for A. aquaticus remained at 12.3% v/v leachate in deionized water, whilst that for G. pulex was only 1%. Sublethal toxicity was judged on the basis of frequency of births and the growth rate of newly born individuals. Tests showed that even a dilution as high as 1:66- would influence the fecundity of a Gammarus population, whilst a dilution of 1:20 would affect the size of an Asellus breeding colony. PMID:15661294

  10. The Impact of Inclusion and Pullout on Middle School Students' Standardized Test Scores

    ERIC Educational Resources Information Center

    Herriott, Tavita S.

    2010-01-01

    The purpose of this study was to determine if there was a difference in students' standardized test scores based on the instructional model their teachers used. One group of students was served under a pullout instructional model. The other was served under an inclusive model. It is not known whether or not the pullout instructional model or the…

  11. Impact of a scene projector array on the nonuniformity of a test article's output image

    Microsoft Academic Search

    Brian P. Beecken; Thomas J. McElmurry; Thomas R. Greenlee

    1999-01-01

    The contribution of a scene projector array to the nonuniformity of a test article's output image has been calculated. In addition to the inherent nonuniformity of the detector array, the output image nonuniformity is dependent upon the nonuniformity of the projector array and the relative positions of emitter images on the detector array as determined by the sampling ratio. In

  12. The trajectory of psychological impact in BRCA1\\/2 genetic testing: does time heal?

    Microsoft Academic Search

    Tammy M. Beran; Annette L. Stanton; Lorna Kwan; Joyce Seldon; Julienne E. Bower; Andrea Vodermaier; Patricia A. Ganz

    2008-01-01

    BACKGROUND: Most research on adjustment of women undergoing genetic testing for breast cancer susceptibility has not followed women for more than 6 months after result receipt and has not evaluated curvilinear patterns in general and cancer-specific adjustment. PURPOSE: This study's primary goal was to examine the trajectory of psychological status in women at risk for breast and ovarian cancer prior

  13. Assessing the Impact of Non-Differential Genotyping Errors on Rare Variant Tests of Association

    Microsoft Academic Search

    Scott Powers; Shyam Gopalakrishnan; Nathan Tintle

    2011-01-01

    Background\\/Aims: We aim to quantify the effect of non-differential genotyping errors on the power of rare variant tests and identify those situations when genotyping errors are most harmful. Methods: We simulated genotype and phenotype data for a range of sample sizes, minor allele frequencies, disease relative risks and numbers of rare variants. Genotype errors were then simulated using five different

  14. Testing vs. Teaching: The Perceived Impact of Assessment Demands on Middle Grades Instructional Practices

    ERIC Educational Resources Information Center

    Faulkner, Shawn A.; Cook, Christopher M.

    2006-01-01

    As a result of the pressures of educational reform and high-stakes assessment, some schools run the risk of foregoing active, student-centered learning activities for building test-taking skills and the memorization of discrete facts (Gredler, 1999; Jackson & Davis, 2000). Coupled with the additional pressure to fulfill the expectations of "No…

  15. The impact of ethical beliefs on decisions about prenatal screening tests: Searching for justification

    Microsoft Academic Search

    Elisa García; Danielle R. M. Timmermans; Evert van Leeuwen

    2008-01-01

    Prenatal screening for Down's syndrome and other chromosomal anomalies has become common obstetrical practice. The purpose of this intervention is to provide women with the information needed to make informed reproductive choices. It is assumed that the ethical beliefs of parents play an important role in decision-making about whether to undergo testing, but little is known about their precise significance.

  16. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...the knee it is within 2 degrees of horizontal and collinear with the longitudinal centerline of the femur. (4) Guide the pendulum so that there is no significant lateral vertical or rotational movement at time-zero. (5) The test probe velocity...

  17. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...the knee it is within 2 degrees of horizontal and collinear with the longitudinal centerline of the femur. (4) Guide the pendulum so that there is no significant lateral vertical or rotational movement at time-zero. (5) The test probe velocity...

  18. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...the knee it is within 2 degrees of horizontal and collinear with the longitudinal centerline of the femur. (4) Guide the pendulum so that there is no significant lateral vertical or rotational movement at time-zero. (5) The test probe velocity...

  19. Pharmacogenetics and population pharmacokinetics: impact of the design on three tests using the SAEM algorithm

    E-print Network

    Paris-Sud XI, Université de

    (PK) (3). Pharmacogenetic data are mainly studied using non-compartmental meth- ods followed by a one of design on the statistical performances of three different tests used for analysis of pharmacogenetic-way analysis of variance (ANOVA) on the individual parameters of interest (4). More sophisticated approaches

  20. The Impact of Various Quizzing Patterns on the Test Performance of High School Economics Students

    ERIC Educational Resources Information Center

    Robertson, William L.

    2010-01-01

    Presenting college students, in a wide variety of content areas, with frequent announced and unannounced quizzes appears to correlate positively with enhanced test performance. The purpose of this quantitative study was to examine if similar results can be achieved with high school students in a standard economics class. Based on a theoretical…