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1

A Study of He Charpy V-Notch Impact Test.  

National Technical Information Service (NTIS)

Dimensional changes and the development of cracking in the Charpy V-notch impact test have been studied using a low energy blow technique. Notch opening, angle of bend, notch root concentration and lateral expansion are shown to be proportional to the ene...

E. Smith

1973-01-01

2

Predicting reference temperature from instrumented Charpy V-notch impact tests using modified Schindler procedure for computing dynamic fracture toughness  

Microsoft Academic Search

Reactor pressure vessel (RPV) steels are increasingly being characterised in terms of the reference temperature T\\u000a0 and the associated Master Curve (MC) Procedure, following the ASTM E-1921 standard. Though correlations have been proposed to predict the T\\u000a0 from Charpy transition temperature T\\u000a28J or instrumented impact test parameters like T\\u000a4kN, none can be taken as a universal

P. R. Sreenivasan; A. Moitra; S. K. Ray; S. L. Mannan

2004-01-01

3

Results of charpy V-notch impact testing of structural steel specimens irradiated at {approximately}30{degrees}C to 1 x 10{sup 16} neutrons/cm{sup 2} in a commercial reactor cavity  

SciTech Connect

A capsule containing Charpy V-notch (CVN) and mini-tensile specimens was irradiated at {approximately} 30{degrees}C ({approximately} 85{degrees}F) in the cavity of a commercial nuclear power plant to a fluence of 1 x 10{sup 16} neutrons/cm{sup 2} (> 1MeV). The capsule included six CVN impact specimens of archival High Flux Isotope Reactor A212 grade B ferritic steel and five CVN impact specimens of a well-studied A36 structural steel. This irradiation was part of the ongoing study of neutron-induced damage effects at the low temperature and flux experienced by reactor supports. The plant operators shut down the plant before the planned exposure was reached. The exposure of these specimens produced no significant irradiation-induced embrittlement. Of interest were the data on unirradiated specimens in the L-T orientation machined from a single plate of A36 structural steel, which is the same specification for the structural steel used in some reactor supports. The average CVN energy of five unirradiated specimens obtained from one region of the plate and tested at room temperature was {approximately} 99 J, while the energy of 11 unirradiated specimens from other locations of the same plate was 45 J, a difference of {approximately} 220%. The CVN impact energies for all 18 specimens ranged from a low of 32 J to a high of 111 J. Moreover, it appears that the University of Kansas CVN impact energy data of the unirradiated specimens at the 100-J level are shifted toward higher temperatures by about 20 K. The results were an example of the extent of scatter possible in CVN impact testing. Generic values for the CVN impact energy of A36 should be used with caution in critical applications.

Iskander, S.K.; Stoller, R.E.

1997-04-01

4

The evaluation of tempered martensite embrittlement in 4130 steel by instrumented charpy V-notch testing  

NASA Astrophysics Data System (ADS)

Tempered martensite embrittlement (TME) was studied in vacuum-melted 4130 steel with either 0.002 or 0.02 wt pct P. TME was observed as a severe decrease in Charpy V-notch impact energy, from 46 ft-lb. at 200 °C to 35 ft-lb. at 300 °C in the low P alloy. The impact energy of the high P alloy was consistently lower than that of the low P alloy in all tempered conditions. Fracture was transgranular for all specimens; therefore, segregation of P to the prior austenitic grain boundaries was not a factor in the o°Currence of TME. Analysis of load-time curves obtained by instrumented Charpy testing revealed that the embrittlement is associated with a drop in the pre-maximum-load and post-unstable-fracture energies. In specimens tempered at 400 °C the deleterious effect of phosphorus on impact energy became pronounced, a result more consistent with classical temper embrittlement rather than TME. A constant decrease in pre-maximum-load energy due to phosphorus content was observed. The pre-maximum-load energy decreases with increasing tempering temperature in the range of 200 °C to 400 °C, a result explained by the change in work hardening rate. Carbon extraction replicas of polished and etched as-quenched specimens revealed the presence of Fe2MoC and/or Fe3C carbides retained after austenitizing. Ductile crack extension close to the notch root was related to the formation of fine micro voids at the retained carbides.

Zia-Ebrahimi, F.; Krauss, G.

1983-06-01

5

The use of flattened specimens to measure the Charpy V-notch impact properties of thin-wall pipe  

SciTech Connect

API Specification 5L, Supplemental Requirement SR5, 37th Edition, requires that Charpy V-notch (CVN) impact properties of pipe from which full size (0.394 {times} 0.394 inch) transverse specimens cannot be obtained, because of wall-thickness/pipe-diameter limitations, be measured with unflattened 2/3 size (0.263 {times} 0.394 inch) or 1/2-size (0.195 {times} 0.394) transverse specimens. Since the use of subsize specimens is known to introduce significant problems in measuring transition temperature interest has been expressed in the possibility of measuring CVN impact properties with flattened specimens to maximize specimen thickness, i.e., use full wall thickness, when subsize specimens are necessary. The present study was undertaken to examine the merit of this approach.

Williams, D.N.

1989-12-01

6

Study of Tempered Martensite Embrittlement Using Standard and Subsize V-Notch Charpy Specimens.  

National Technical Information Service (NTIS)

Various sizes of V-notch and fatigue precracked Charpy specimens, tested in impact and slow bend, were used to study tempered martensite embrittlement in a 4340 steel. When plotted as a function of tempering temperature, the results showed that the magnit...

T. M. F. Ronald

1969-01-01

7

Performance verification of impact machines for testing plastics  

Microsoft Academic Search

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

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

1999-01-01

8

Development in the instrumented impact test computer aided instrumented impact testing system  

Microsoft Academic Search

To determine the toughness of materials, Charpy V notch test has been widely utilized over the world. This method is easy to conduct, but obtained values are very qualitative. Instrumented test has also a long history and gives us a loading history during impact. However this method is also still remaining in a range of screening test.Using a precracked specimen,

Toshiro Kobayashi

2002-01-01

9

Toughness Study of Drillpipes by Use of Instrumented Impact Tests  

Microsoft Academic Search

The toughness behavior of API Grades E and G pipe was studied by use of the instrumented impact test on Charpy V-notch specimens. This study was done at various locations in the pipes, including the upset, nonupset, and transition from upset to nonupset regions. The use of instrumented impact testing made it possible to distinguish the stage of crack initiation

Muralidhar Tumuluru

1987-01-01

10

Effects of oxidation on the impact energy of Hastelloy S and Hastelloy C-4 Charpy V-notch specimens heated in air at 600 to 800  

SciTech Connect

The /sup 90/SrF/sub 2/ heat source being developed at PNL utilizes a Hastelloy S or Hastelloy C-4 outer capsule having a 0.5-in.-thick wall to contain the Hastelloy C-276 inner capsule. The primary objective of the study was to demonstrate that the air oxidation of the outer capsule that could occur during heat-source service would not degrade the ductility and Charpy impact strength of the capsule below the licensing requirements given in Section 1.1. The /sup 90/SrF/sub 2/ heat source under development is intended for general-purpose use. Compatibility considerations limit the interface temperature between the /sup 90/SrF/sub 2/ and Hastelloy C-276 inner capsule to a maximum of 800/sup 0/C. The outer capsule surface temperature will be somewhat less than 800/sup 0/C, and depending on the service, may be substantially lower. The oxidation tests were therefore carried out at 600/sup 0/ to 800/sup 0/C for exposures up to 10,000h to cover the range of temperature the outer capsule might expect to encounter in service. The results showed that the oxidation of Hastelloy S and Hastelloy C-4 in air at 600/sup 0/ to 800/sup 0/C is very slow, and both alloys form adherent oxide layers that serve to protect the underlying metal. Subsurface attack of Hastelloy S and Hastelloy C-4 due to oxidation was greater than expected, considering the slow oxidation rates of the two alloys at 600/sup 0/ to 800/sup 0/C. Estimates of subsurface attack, determined from micrographs of the oxidized specimens, showed erratic results and it was impossible to assign any type of rate equation to the subsurface attack. A conservative estimate of long-term effects can be made using a linear extrapolation of the test results. There were no significant differences between the room-temperature Charpy impact energy of Hastelloy S and Hastelloy C-4 specimens oxidized in air at 600/sup 0/ to 800/sup 0/C and control specimens heated in vacuum.

Fullam, H.T.

1981-01-01

11

Application of computer techniques to charpy impact testing of irradiated pressure vessel steels  

Microsoft Academic Search

A Rockwell AIM 65 microcomputer has been modified to control a remote Charpy V-notch impact test machine. It controls not only handling and testing of the specimen but also transference and storage of instrumented Charpy test data. A system of electrical solenoid activated pneumatic cylinders and switches provides the interface between the computer and the test apparatus. A command language

M. P. Landow; E. O. Fromm; J. S. Perrin; M Bruce Vieth

1982-01-01

12

46 CFR 54.05-17 - Weld toughness test acceptance criteria.  

Code of Federal Regulations, 2011 CFR

...Charpy V-notch impact tests the energy absorbed in both the weld metal and heat affected zone impact tests...parent material. (2) For heat affected zone specimens...parent material. (3) For heat affected zone...

2011-10-01

13

46 CFR 54.05-17 - Weld toughness test acceptance criteria.  

Code of Federal Regulations, 2012 CFR

...Charpy V-notch impact tests the energy absorbed in both the weld metal and heat affected zone impact tests...parent material. (2) For heat affected zone specimens...parent material. (3) For heat affected zone...

2012-10-01

14

Influence of thermal conditioning media on Charpy specimen test temperature.  

National Technical Information Service (NTIS)

The Charpy V-notch (CVN) impact test is used extensively for determining the toughness of structural materials. Research programs in many technologies concerned with structural integrity perform such testing to obtain Charpy energy vs temperature curves. ...

R. K. Nanstad R. L. Swain R. G. Berggren

1989-01-01

15

Crack initiation and arrest characteristics of 9% Ni steels with various Charpy v-notch energy valves  

SciTech Connect

Nine percent Ni steel, used in the construction of LNG tanks where brittle fracture can result in catastrophic damage, requires a high fracture toughness. The materials tested in this study for a steel with this property are quenched and temepred (QT), double normalized and tempered (NNT), and as rolled 9% Ni steel plates. The crack initiaton, propagation, and arrest charactristics of these plates at 103 K were studied with respect to the 2-mm V-Notch Charpy impact energy at 77 K. Among the results are 1) that the increase in the Charpy impact energy, mainly attained by reducing the sulfur content, improves the resistance to ductile crack initiation and propagation for the QT steels; 2) that the QT steels have larger crack opening displacement values than NNT and as-rolled steels even when the Charpy impact energy is the same; and 3) that all QT steels tested arrest the brittle crack that runs 350 mm in the starter section at a stress as large as 490 MPa. Chemcial composition table and test plots are given. Weldability is analyzed.

Nakano, Y.; Hirose, K.; Kamada, A.; Suzuki, S.

1982-01-01

16

Three-dimensional elastic stress fields ahead of blunt V-notches in finite thickness plates  

Microsoft Academic Search

Based on detailed three-dimensional (3D) finite element analyses, elastic fields in front of blunt V-notches in finite thickness plates subjected to uniaxial far-end tensile stress have been investigated. By comparison with the corresponding planar V-notch fields and 3D through-thickness sharp crack fields, various aspects of the 3D fields of the blunt V-notches in finite thickness plates are revealed: (1) The plate

Zhenhuan Li; Wanlin Guo

2001-01-01

17

Evaluation of the stress singularities of plane V-notches in bonded dissimilar materials  

Microsoft Academic Search

According to the linear theory of elasticity, there exists a combination of different orders of stress singularity at a V-notch tip of bonded dissimilar materials. The singularity reflects a strong stress concentration near the sharp V-notches. In this paper, a new way is proposed in order to determine the orders of singularity for two-dimensional V-notch problems. Firstly, on the basis

Zhongrong Niu; Dali Ge; Changzheng Cheng; Jianqiao Ye; Naman Recho

2009-01-01

18

Three-dimensional vibrations of cylindrical elastic solids with V-notches and sharp radial cracks  

Microsoft Academic Search

This paper provides free vibration data for cylindrical elastic solids, specifically thick circular plates and cylinders with V-notches and sharp radial cracks, for which no extensive previously published database is known to exist. Bending moment and shear force singularities are known to exist at the sharp reentrant corner of a thick V-notched plate under transverse vibratory motion, and three-dimensional (3-D)

O. G. McGee; J. W. Kim

2010-01-01

19

Vibrations Of Circular Plates Having V-notches Or Sharp Radial Cracks  

Microsoft Academic Search

This paper provides the first known free vibration data for circular plates having V-notches. A V-notch has bending moment singularities at its sharp corner due to the transverse vibratory motion. A theoretical analysis is undertaken using two sets of admissible displacement functions, (1) algebraic-trigonometric polynomials and (2) corner functions. These function sets are used with the Ritz method. The first

A. W. Leissa; O. G. McGee; C. S. Huang

1993-01-01

20

Experimental fracture study for a V-notched soda-lime glass specimen  

Microsoft Academic Search

Engineering components made of soda-lime glass sometimes contain notches with different shapes, particularly V-shaped notches. A V-notch plays the role of a stress concentrator that dramatically decreases the load bearing capacity of the component. Since fracture in soda-lime glass occurs suddenly due to its brittleness, it is necessary to estimate the fracture resistance of V-notched glass components under different loading

M. R. Ayatollahi; A. R. Torabi

2009-01-01

21

Mechanical aspects of the Charpy impact test  

Microsoft Academic Search

A comparative experimental and FEM study has been carried out, in order to investigate dynamic and constraint aspects of the Charpy test. Standard V-notch Charpy specimens were tested under dynamic and static loading conditions. 2-D plane strain and 3-D models were employed in numerical analysis. In order to incorporate strain-rate effects, an elastic-viscoplastic constitutive equation has been applied, based on

A. Rossoll; C. Berdin; P. Forget; C. Prioul; B. Marini

1999-01-01

22

Impact properties of irradiated HT9 from the fuel duct of FFTF  

Microsoft Academic Search

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 378504 *C. The impact tests were performed for the small V-notched Charpy specimens with dimensions of

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

2012-01-01

23

Three-dimensional vibrations of cylindrical elastic solids with V-notches and sharp radial cracks  

NASA Astrophysics Data System (ADS)

This paper provides free vibration data for cylindrical elastic solids, specifically thick circular plates and cylinders with V-notches and sharp radial cracks, for which no extensive previously published database is known to exist. Bending moment and shear force singularities are known to exist at the sharp reentrant corner of a thick V-notched plate under transverse vibratory motion, and three-dimensional (3-D) normal and transverse shear stresses are known to exist at the sharp reentrant terminus edge of a V-notched cylindrical elastic solid under 3-D free vibration. A theoretical analysis is done in this work utilizing a variational Ritz procedure including these essential singularity effects. The procedure incorporates a complete set of admissible algebraic-trigonometric polynomials in conjunction with an admissible set of “edge functions” that explicitly model the 3-D stress singularities which exist along a reentrant terminus edge (i.e., ?>180°) of the V-notch. The first set of polynomials guarantees convergence to exact frequencies, as sufficient terms are retained. The second set of edge functions—in addition to representing the corner stress singularities—substantially accelerates the convergence of frequency solutions. This is demonstrated through extensive convergence studies that have been carried out by the investigators. Numerical analysis has been carried out and the results have been given for cylindrical elastic solids with various V-notch angles and depths. The relative depth of the V-notch is defined as (1-c/a), and the notch angle is defined as (360°-?). For a very small notch angle (1° or less), the notch may be regarded as a “sharp radial crack.” Accurate (four significant figure) frequencies are presented for a wide spectrum of notch angles (360°-?), depths (1-c/a), and thickness ratios (a/h for plates and h/a for cylinders). An extended database of frequencies for completely free thick sectorial, semi-circular, and segmented plates and cylinders are also reported herein as interesting special cases. A generalization of the elasticity-based Ritz analysis and findings applicable here is an arbitrarily shaped V-notched cylindrical solid, being a surface traced out by a family of generatrix, which pass through the circumference of an arbitrarily shaped V-notched directrix curve, r(?), several of which are described for future investigations and close extensions of this work.

McGee, O. G.; Kim, J. W.

2010-02-01

24

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...

25

Size effect in beams with rounded-tip V-notch  

Microsoft Academic Search

Stresses and strains in a beam with a single-edge rounded-tip V-notch subjected to bending were analyzed by the method of\\u000a finite elements by using nonconforming quadrilateral elements under the assumption that the material is linearly elastic.\\u000a We studied the influence of the depth of the notcha, its radius of curvature ?, the angle of the notch ?, and the height

A. Carpinteri; R. Brighenti; A. Spagnoli

1996-01-01

26

Singular stress fields at V-notch tips in elastoplastic pressure-sensitive materials  

Microsoft Academic Search

Summary Elastoplastic solutions with the higher-order terms for V-notches in materials exhibiting pressure-sensitive yielding and plastic volumetric deformations are presented. It is shown that under plane strain conditions the variable-separable solution exists within some limited pressure-sensitivities. The limit values grow significantly with increasing notch angle. The leading singularity is a decreasing function of notch angle. The small notch angle can

H. Yuan

1996-01-01

27

Performance verification of impact machines for testing plastics  

SciTech Connect

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.

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

1999-12-01

28

In-plane and out-of-plane stress field solutions for V-notches with end holes  

Microsoft Academic Search

Closed form expressions of stress distributions for V-notches with end holes and varying opening angles are presented. The\\u000a solution for the elastic plane problem is obtained by means of the Kolosov-Muskhelishvili approach by using a reduced number\\u000a of complex terms. The exponents of the potential functions are simple combinations of Williams’ eigenvalues for pointed V-notches\\u000a in mode I and mode

Michele Zappalorto; Paolo Lazzarin

2011-01-01

29

Effects of Notch Location on Heat-affected Zone Impact Properties of SA516 Steels  

Microsoft Academic Search

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

Jaekeun Hong; Jihong Park; Chungyun Kang

2008-01-01

30

Toughness study of drillpipes by use of instrumented impact tests  

SciTech Connect

The toughness behavior of API Grades E and G pipe was studied by use of the instrumented impact test on Charpy V-notch specimens. This study was done at various locations in the pipes, including the upset, nonupset, and transition from upset to nonupset regions. The use of instrumented impact testing made it possible to distinguish the stage of crack initiation from that of propagation during the impact tests. The study revealed that the Grade E pipe possessed poor toughness as evidenced by the low energy values required to propagate the crack. The toughness behavior varied from upset to nonupset regions in the Grade E pipe. The Grade G pipe, on the other hand, exhibited superior toughness uniformly throughout its length as revealed by the high energy values required for crack propagation. Scanning electron microscope (SEM) and metallographic techniques were used to explain the fracture behavior of both types of pipe. The toughness of Grade E pipe, and therefore its tolerance to the presence of defects, can be improved by adopting a quench-and-temper heat treatment.

Tumuluru, M.

1987-09-01

31

Effects of annealing time on the recovery of Charpy V-notch properties of irradiated high-copper weld metal  

SciTech Connect

One of the options to mitigate the effects of irradiation on reactor pressure vessels is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. An important issue to be resolved is the effect on the toughness properties of reirradiating a vessel that has been annealed. This paper describes the annealing response of irradiated high-copper submerged-arc weld HSSI 73W. For this study, the weld has been annealed at 454 C (850 F) for lengths of time varying between 1 and 14 days. The Charpy V-notch 41-J (30-ft-lb) transition temperature (TT{sub 41J}) almost fully recovered for the longest period studied, but recovered to a lesser degree for the shorter periods. No significant recovery of the TT{sub 41J} was observed for a 7-day anneal at 343 C (650 F). At 454 C for the durations studied, the values of the upper-shelf impact energy of irradiated and annealed weld metal exceeded the values in the unirradiated condition. Similar behavior was observed after aging the unirradiated weld metal at 460 and 490 C for 1 week.

Iskander, S.K.; Sokolov, M.A.; Nanstad, R.K. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

1994-12-31

32

Vibrations Of Circular Plates Having V-notches Or Sharp Radial Cracks  

NASA Astrophysics Data System (ADS)

This paper provides the first known free vibration data for circular plates having V-notches. A V-notch has bending moment singularities at its sharp corner due to the transverse vibratory motion. A theoretical analysis is undertaken using two sets of admissible displacement functions, (1) algebraic-trigonometric polynomials and (2) corner functions. These function sets are used with the Ritz method. The first set guarantees convergence to the exact frequencies as sufficient terms are taken. The second set represents the corner singularities exactly, and accelerates convergence greatly. Numerical results are given for non-dimensional frequencies of completely free circular plates having various notch angles and depths. As the notch angle becomes very small, a sharp radial crack ensues. Convergence studies demonstrate the necessity of adding corner functions to achieve accurate frequencies. Extensive, accurate (five significant figure) frequencies are presented for the spectrum of notch angles (0°, 1°, 5°, 10°, 30°, 60° and 90°) and depths. The effect of the Poisson ratio on the frequencies in the case of shallow notches is also investigated. Sharp notches are found to reduce each of the first six frequencies from those of a complete circular plate, whereas large notch angles can increase some of the frequencies. Nodal patterns are shown for plates having 5° notches. The first known frequencies for completely free sectorial, semi-circular and segmented plates are also given as special cases.

Leissa, A. W.; McGee, O. G.; Huang, C. S.

1993-02-01

33

Dynamic JR curves and tension-impact properties of AISI 308 stainless steel weld  

Microsoft Academic Search

In this paper, instrumented tension-impact (dynamic tensile) and instrumented Charpy impact test results for AISI 308 stainless steel welds at room temperature are reported. A few Charpy specimens precracked to a\\/W (crack length to width ratio) ratios of 0.42 to 0.59 were also tested. Dynamic yield strength obtained from tension-impact test agrees well with that from Charpy V-notch specimens. The

P. R. Sreenivasan; S. L. Mannan

2000-01-01

34

Procedure improves line pipe Charpy test interpretation  

Microsoft Academic Search

The Charpy V-notch (CVN) impact test is a method of characterizing a line-pipe material`s notch toughness and resistance to fracture growth. Although CVN testing of line pipe material is routine, test results are sometimes misinterpreted because of specimen size and load rate on actual toughness transition behavior. These effects are readily accounted for by a simple mathematical procedure, offered here,

Rosenfeld

1997-01-01

35

Charpy V-notch properties and microstructures of narrow gap ferritic welds of a quenched and tempered steel plate  

SciTech Connect

Multipass welds of quenched and tempered 50-mm-thick steel plate have been deposited by a single wire narrow gap process using both gas metal arc welding (GMAW) and submerged arc welding (SAW). Of the five welds, two reported much lower Charpy V-notch (CVN) values when tested at {minus} 20 C. The CVN toughness did not correlate with either the welding process or whether the power source was pulsed or nonpulsed. The only difference in the ferritic microstructure between the two welds of low Charpy values and the three of high values was the percentage of acicular ferrite. There was no effect of the percentage of as-deposited reheated zones intersected by the Charpy notch or the microhardness of the intercellular-dendritic regions. In all welds, austenite was the microconstituent between the ferrite laths. The percentage of acicular ferrite correlated with the presence of MnO, TiO{sub 2}, {gamma} Al{sub 2}O{sub 3}, or MnO. Al{sub 2}O{sub 3} as the predominant crystalline compound in the oxide inclusions. In turn, the crystalline compound depended on the aluminum-to-titanium ratio in both the weld deposits and the oxide inclusions. In addition to the presence of less acicular ferrite, the two welds that showed lower Charpy values also reported more oxide inclusions greater than 1 {micro}m in diameter. The combination of more oxide inclusions greater than 1 {micro}m and less acicular ferrite is considered to be the explanation for the lower Charpy values.

Powell, G.L.F.; Herfurth, G. [Commonwealth Scientific and Industrial Research Organization, Woodville (Australia)

1998-11-01

36

Tensile testing and scanning electron microscope examination of Charpy impact specimens from the HFBR  

Microsoft Academic Search

The Materials Technology Group of the Department of Nuclear Energy (DNE) at Brookhaven National Laboratory (BNL) has performed a fractographic examination of neutron irradiated and unirradiated Charpy V'' notch specimens which have been deformed to failure in a tensile testing apparatus. The evaluation was carried out using a scanning electron microscope (SEM) to evaluate the fracture mode. Photomicrographs were then

C. J. Czajkowski; M. H. Schuster; T. C. Roberts

1990-01-01

37

Effect of low temperatures on charpy impact toughness of austempered ductile irons  

Microsoft Academic Search

Impact properties of standard American Society for Testing Materials (ASTM) grades of austempered ductile iron (ADI) were\\u000a evaluated at subzero temperatures in unnotched and V-notched conditions and compared with ferritic and pearlitic grades of\\u000a ductile irons (DIs). It was determined that there is a decrease in impact toughness for all ADI grades when there is a decrease\\u000a in content of

Mikhail V. Riabov; Yury S. Lerner; Mohammed F. Fahmy

2002-01-01

38

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

Microsoft Academic Search

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.

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

2007-01-01

39

Effects of notch position of the Charpy impact specimen on the failure behavior in heat affected zone  

Microsoft Academic Search

Experimental and numerical studies were performed to examine the effects of notch position on the failure behavior and energy absorption when the Charpy V-notch impact test is made at 1°C. Carbon steel plate (SA-516 Gr. 70) with thickness of 25mm usually used for pressure vessel was welded by Shielded Metal-Arc Welding method and specimens were fabricated from the welded plate.

Y. C. Jang; J. K. Hong; J. H. Park; D. W. Kim; Y. Lee

2008-01-01

40

TAYLOR IMPACT TESTS: DETAILED REPORT  

Microsoft Academic Search

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

Biswajit Banerjee

41

Fictitious notch rounding concept applied to sharp V-notches: Evaluation of the microstructural support factor for different failure hypotheses. Part I: Basic stress equations  

Microsoft Academic Search

With the aim to perform a comprehensive and accurate evaluation of the microstructural support factor of sharp V-notches (Neuber’s notch rounding concept), in Part I of this contribution, the indispensable theoretical tools, especially the basic stress equations, are reconsidered and amended in respect of accuracy of results. First, the analytical solution derived by Neuber [Neuber H. Kerbspannungslehre. 2nd ed. Berlin:

F. Berto; P. Lazzarin; D. Radaj

2008-01-01

42

Development of a Test for Impact Protection.  

National Technical Information Service (NTIS)

An impact test apparatus has been designed, and testing procedures have been proposed to measure systematically on flexible, semi-rigid and rigid impact protection systems their abilities to absorb kinetic energy and to distribute peak impact pressure awa...

J. M. Akridge W. J. Leverett W. D. Freeston M. K. Rao W. D. McLeod

1973-01-01

43

Dynamic impact testing with servohydraulic testing machines  

NASA Astrophysics Data System (ADS)

The design concept of “Crashworthiness” requires the information on material behaviour under dynamic impact loading in order to describe and predict the crash behaviour of structures. Especially the transport related industries, like car, railway or aircraft industry, pursue the concept of lightweight design for a while now. The materials' maximum constraint during loading is pushed to permanently increasing figures. This means in terms of crashworthiness that the process of energy absorption in structures and the mechanical behaviour of materials must well understood and can be described appropriately by material models. In close cooperation with experts from various industries and research institutes Instron has developed throughout the past years a new family of servohydraulic testing machines specifically designed to cope with the dynamics of high rate testing. Main development steps are reflected versus their experimental necessities.

Bardenheier, R.; Rogers, G.

2006-08-01

44

Development of ball impact test system  

Microsoft Academic Search

We introduce in this paper background and development of the high-speed ball shear test systems, in particular a specific ball impact test system. Measured impact force profiles and corresponding structural dynamics calibrations are provided for the understanding of characteristics of this particular package-level test methodology as well as transient structural responses of solder joints subjected to impact loads. A design

Chang-Lin Yeh; Yi-Shao Lai

2006-01-01

45

PEDESTRIAN HEAD IMPACT TESTING AND PCDS RECONSTRUCTIONS  

Microsoft Academic Search

Pedestrian research and testing at the NHTSA Vehicle Research and Test Center has recently focused on assessment of proposed ISO and EEVC head impact test procedures, and extension of these procedures to additional vehicle frontal surfaces. In addition to test parameter sensitivity evaluation, reconstruction of PCDS (Pedestrian Crash Data Study) cases with laboratory impact tests and computer simulations has been

Jason A. Stammen; Roger A. Saul; Brian Ko

46

Procedure improves line pipe Charpy test interpretation  

SciTech Connect

The Charpy V-notch (CVN) impact test is a method of characterizing a line-pipe material`s notch toughness and resistance to fracture growth. Although CVN testing of line pipe material is routine, test results are sometimes misinterpreted because of specimen size and load rate on actual toughness transition behavior. These effects are readily accounted for by a simple mathematical procedure, offered here, which enables extrapolation of the full-scale transition curve from as little as a single subsize specimen test. This procedure is useful when the toughness transition curve is incomplete or nonexistent. Toughness data may be incomplete because the API 5L toughness test establishes minimum performance at a single temperature, which does not reveal the full transition curve. Toughness data may be nonexistent because the first requirements for toughness testing of line pipe appeared in the 16th Edition of API 5LX in 1969, and those requirements remain at the option of the purchaser today.

Rosenfeld, M.J. [Kiefner and Associates Inc., Worthington, OH (United States)

1997-04-14

47

Testing Laminated Glass for Impact Resistance  

Microsoft Academic Search

Comparative testing of laminated glass made up by different combinations for impact resistance has been performed. The testing corroborates the possibility of using glass subjected to special thermal treatment (STT) in the production of impact-resistant laminated glass. Glasses based on STT glass satisfy the impact resistance requirements of GOST R 51136–98, and their thickness and weight are a factor of

A. I. Shutov; A. N. Frank; I. A. Novikov; A. S. Ostapko; A. S. Bonchuk; A. N. Burdov

2004-01-01

48

Mechanical Impact Testing: A Statistical Measurement.  

National Technical Information Service (NTIS)

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 mechani...

C. D. Engel S. D. Herald S. E. Davis

2005-01-01

49

Dynamic impact testing with servohydraulic testing machines  

Microsoft Academic Search

The design concept of ``Crashworthiness'' requires the information on material behaviour under dynamic impact loading in order to describe and predict the crash behaviour of structures. Especially the transport related industries, like car, railway or aircraft industry, pursue the concept of lightweight design for a while now. The materials' maximum constraint during loading is pushed to permanently increasing figures. This

R. Bardenheier; G. Rogers

2006-01-01

50

Defense Waste Processing Facility canister impact testing  

Microsoft Academic Search

This report summarizes impact testing of seven Defense Waste Processing Facility (DWPF) high level waste canisters during FY 1988. Impact testing was conducted to demonstrate compliance of DWPF canisters with the drop test specification of the Waste Acceptance Preliminary Specification. The prototypical stainless steel canisters were filled with simulated waste to about 85% capacity at Savannah River Laboratory (SRL). They

K. M. Olson; J. M. Alzheimer

1989-01-01

51

Oblique impact testing of bicycle helmets  

Microsoft Academic Search

The performance of bicycle helmets was investigated in oblique impacts with a simulated road surface. The linear and rotational accelerations of a headform, fitted with a compliant scalp and a wig, were measured. The peak rotational accelerations, the order of 5krads?2 when the tangential velocity component was 4ms?1, were only slightly greater than in comparable direct impact tests. Oblique impact

N. J. Mills; A. Gilchrist

2008-01-01

52

Drop impact test - mechanics & physics of failure  

Microsoft Academic Search

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

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

2002-01-01

53

Hypervelocity impact tests of optical sensors  

SciTech Connect

Hypervelocity tests of spacecraft optical sensors were conducted to determine if the optical signature from an impact inside the sunshade resembled signals observed on-orbit. Impact tests were conducted in darkness and with the ejected debris illuminated. {copyright} {ital 1996 American Institute of Physics.}

Browning, J.S.; Montoya, J.L. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

1996-05-01

54

Light-weight radioisotope heater impact tests  

SciTech Connect

The light-weight radioisotope heater unit (LWRHU) is a {sup 238}PuO{sub 2}-fueled heat source designed to provide one thermal watt in each of various locations on a spacecraft. Los Alamos National Laboratory designed, fabricated, and safety tested the LWRHU. The heat source consists of a hot-pressed {sup 238}PuO{sub 2} fuel pellet, a Pt-30Rh vented capsule, a pyrolytic graphite insulator, and a fineweave-pierced fabric graphite aeroshell assembly. To compare the performance of the LWRHUs fabricated for the Cassini mission with the performance of those fabricated for the Galileo mission, and to determine a failure threshold, two types of impact tests were conducted. A post-reentry impact test was performed on one of 180 flight-quality units produced for the Cassini mission and a series of sequential impact tests using simulant-fueled LWRHU capsules were conducted respectively. The results showed that deformation and fuel containment of the impacted Cassini LWRHU was similar to that of a previously tested Galileo LWRHU. Both units sustained minimal deformation of the aeroshell and fueled capsule; the fuel was entirely contained by the platinum capsule. Sequential impacting, in both end-on and side-on orientations, resulted in increased damage with each subsequent impact. Sequential impacting of the LWRHU appears to result in slightly greater damage than a single impact at the final impact velocity of 50 m/s.

Reimus, M.A.H.; Rinehart, G.H.; Herrera, A. [and others

1998-12-31

55

Kolsky Bar Impact Test Facility  

SciTech Connect

Testing for the Kolsky Bar is conducted at Los Alamos National Laboratory, Los Alamos, New Mexico. The Kolsky bar is operated by the Dynamic testing team of NMT-11, (Nuclear Material Technology Division) to enable measurements of stress-strain characteristics for the MST-8 (Material Science and Technology) personnel. The Kolsky Bar is located at the Plutonium Facility at TA-55 (Tech Area).

Contreras, P.; Montoya, J.

1998-12-31

56

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

NASA Astrophysics Data System (ADS)

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 et sollicitees en traction et essais de tenacite sur eprouvettes prefissurees. Base sur le concept de la statistique de Weibull, l'approche locale developpee par le groupe Beremin a ete utilisee pour decrire la probabilite de rupture par clivage en fonction de la contrainte appliquee aussi bien qu'en fonction de l'energie Charpy obtenue. Le calcul par elements finis a ete realise pour determiner la distribution de la deformation et des contraintes en pointe d'entaille et de fissure. La nouvelle approche introduite decrit bien les resultats experimentaux. Les points d'initiation du clivage ont ete identifies au MEB et par la suite, avec la technique de faisceau d'ions focalise, sectionnes, polis et examines. L'examen de la microstructure sous le point d'initiation revele clairement que le clivage s'initie par un mecanisme d'empilement de dislocations ou les dislocations sont arretees aux joints de grain, aux interfaces de perlite/ferrite ou de perlite qui agissent comme barrieres physiques.

Bouchard, Real

57

Dynamic Force Measurement: Instrumented Charpy Impact Testing.  

National Technical Information Service (NTIS)

Maximum forces and forces at general yield measured on impact reference materials in round robin testing are reported. These dynamic results are compared with static force calibration of instrumented strikers. One machine in the round robin was identified...

C. N. McCowan E. Lucon J. D. Splett

2008-01-01

58

Instrumented tensile-impact tests of bone  

Microsoft Academic Search

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

S. Saha; W. C. Hayes

1974-01-01

59

Impact and vibration testing of shipping containers  

NASA Astrophysics Data System (ADS)

Equations are developed for experimental evaluation of restoring and dissipative parameters, as used in a non-linear mathematical unit load model. A specially developed transportation damage simulation test jig is described. This jig is suitable for impact and vibration load reproduction on bottom tier containers in unit loads, but only a single container sample is needed. A detailed case study is described, exemplifying how these parameters may be evaluated by impact (shock) or vibration testing of corrugated produce shipping containers. The initial spring rate K0 was found to be approximately equal in impact and vibration loading. The parameter r, expressing the non-linearity, was significantly larger in vibration loading than in impact loading. On the other hand, both viscous and Coulomb damping are significantly greater in impact loading than in vibration loading. The same modus operandi may be used for determination of dynamic restoring and dissipative parameters of other products, such as cushioning foams and elastomers.

Peleg, K.

1984-04-01

60

Hypervelocity impact testing of spacecraft optical sensors  

SciTech Connect

Hypervelocity tests of spacecraft optical sensors were conducted to determine if the optical signature from an impact inside the optical sensor sunshade resembled signals that have been observed on-orbit. Impact tests were conducted in darkness and with the ejected debris illuminated. The tests were conducted at the Johnson Space Center Hypervelocity Impact Test Facility. The projectile masses and velocities that may be obtained at the facility are most representative of the hypervelocity particles thought to be responsible for a group of anomalous optical sensors responses that have been observed on-orbit. The projectiles are a few micrograms, slightly more massive than the microgram particles thought to be responsible for the signal source. The test velocities were typically 7.3 km/s, which are somewhat slower than typical space particles.

NONE

1995-07-01

61

Rail Impact Test of Rotary Towed Sweeper.  

National Technical Information Service (NTIS)

The U. S. Army Defense Ammunition Center and School (USADACS), Validation Engineering Division (SMCAC-DEV), was tasked by the U. S. Army Tank-Automotive Command to rail impact test per MIL-STD-810D, Military Standard Environmental Test Methods and Enginee...

A. C. McIntosh

1990-01-01

62

Hypervelocity impact tests against metallic meshes  

Microsoft Academic Search

The purpose of this study is to investigate fragment clouds generated by hypervelocity impacts (HVIs) on metallic meshes. The HVIs tests have been conducted with a two-stage light gas gun facility at Kyushu Institute of Technology. Projectiles were launched at 3km\\/s. Radiographs of the fragment cloud generated by the impact of the projectile on the mesh were taken with three

M. Higashide; M. Tanaka; Y. Akahoshi; S. Harada; F. Tohyama

2006-01-01

63

Defense Waste Processing Facility canister impact testing  

SciTech Connect

This report summarizes impact testing of seven Defense Waste Processing Facility (DWPF) high level waste canisters during FY 1988. Impact testing was conducted to demonstrate compliance of DWPF canisters with the drop test specification of the Waste Acceptance Preliminary Specification. The prototypical stainless steel canisters were filled with simulated waste to about 85% capacity at Savannah River Laboratory (SRL). They were received from SRL in April 1988. Each canister was approximately 300 cm (9 ft 10 in.) long, and 61 cm (2 ft) in diameter, and weighed about 2150 kg (4740 lb). Each canister was dropped twice from a height of 7 m (23 ft). The first drop was a vertical bottom impact where the bottom of the canister was oriented parallel to the impact pad. The second was a center-of-gravity-over-the-corner top impact. Procedures used to examine the canisters were the application and analysis of strain circles, helium leak testing, dye penetrant examination, and canister dimensional measurements. 39 refs., 39 figs., 11 tabs.

Olson, K.M.; Alzheimer, J.M.

1989-09-01

64

Design of an impact abrasion testing machine  

NASA Astrophysics Data System (ADS)

By using a cam-flat follower-impact shaft with a crank-flat rotating anvil system, the machine to be described can create various impact abrasion conditions to simulate a large range of industrial situations encountered in this field. The main features of the machine are the long working life of the flat rotating anvil, which works in the same way as that of the disk in a pin-on-disk wear tester, and the accurate control of both the impact energy delivered to the specimen and the total sliding distance of the specimen on the anvil. Statistical analysis of test results on the machine with EN24 steel and cast high manganese steel shows that the uncertainty of the population mean is within +/- 4.7% of the sample mean under a 95% confidence level of student distribution, which indicates a very good accuracy of test.

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

1994-04-01

65

REAR IMPACT TEST METHODOLOGIES: QUASISTATIC AND DYNAMIC  

Microsoft Academic Search

The performance of a vehicle's seat back in rear impact accidents can significantly affect occupant kinematics and resulting injury potential. The only current United States (U.S.) government regulation addressing seat back strength is outlined in Federal Motor Vehicle Safety Standard (FMVSS) 207, Seating Systems (1). The test method outlined in this regulation is only partially predictive of seat performance in

Brian R. Herbst; Steven E. Meyer; Arin A. Oliver; Stephen M. Forrest

66

Numerical simulations of motorcycle helmet impact tests  

Microsoft Academic Search

The main objective of this study was to simulate experimental impact tests on a commercially available motorcycle helmet and to develop a virtual design tool. The mechanical properties of the shell and the foam liner of the helmet were estimated from existing material data taken from the open literature. The material data were adjusted to match the temperature conditioning of

M. Aiello; U. Galvanetto; L. Iannucci

2007-01-01

67

Impact and vibration testing of shipping containers  

Microsoft Academic Search

Equations are developed for experimental evaluation of restoring and dissipative parameters, as used in a non-linear mathematical unit load model. A specially developed transportation damage simulation test jig is described. This jig is suitable for impact and vibration load reproduction on bottom tier containers in unit loads, but only a single container sample is needed. A detailed case study is

K. Peleg

1984-01-01

68

Full-scale aircraft impact test for evaluation of impact forces: Part 1, Test plan, test method, and test results  

SciTech Connect

One of the factors considered in the design of critical concrete structures is the estimation of the global elasto-plastic structural response caused by the accidental impact of an aircraft. To estimate the response of the structure, the impact force (the force versus time relationship) must be known. Previous analytical studies have derived the forcing function using the impact velocity of the aircraft and the calculated mass and strength distribution of the aircraft. This paper describes a test conducted on April 19, 1988, at an existing rocket sled facility at Sandia National Laboratories in Albuquerque, New Mexico, USA, in which an actual F-4 Phantom aircraft was impacted at a nominal velocity of 215 m/s into an essentially rigid block of concrete. This was accomplished by supporting the F-4 on four struts that were attached to the sled track by carriage shoes to direct the path of the aircraft. Propulsion was accomplished by two stages of rockets. The concrete target was 'floated' on a set of air bearings. Data acquisition consisted of measurements of the acceleration of the fuselage and engines of the F-4, and measurements of the displacement, velocity and acceleration of the concrete target. High-speed photography recorded the impact process and also permitted the determination of the impact velocity. This paper describes the test plan, method and results, while a companion paper discusses the analyses of the results. 6 refs., 11 figs.

von Riesemann, W.A.; Parrish, R.L.; Bickel, D.C.; Heffelfinger, S.R.; Muto, K.; Sugano, T.; Tsubota, H.; Koshika, N.; Suzuki, M.; Ohrui, S.

1989-03-01

69

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

NASA Astrophysics Data System (ADS)

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.

Hong, Jaekeun; Park, Jihong; Kang, Chungyun

70

Mechanical damping in instrumented impact testing  

Microsoft Academic Search

Instrumented impact testing is an effective tool for the study of high-speed fracture of polymeric materials. The evaluation\\u000a of force signals is usually impeded by dynamic effects. These can be compensated by mechanical damping which, however, leads\\u000a to additional energy absorption. A model and a technique were developed for the determination of the viscoelastic properties\\u000a of the damper. Correction of

Akos. Bezeredi; Gyorgy. Voros; Bela. Pukanszky

1997-01-01

71

16 CFR 1203.11 - Marking the impact test line.  

Code of Federal Regulations, 2013 CFR

...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...

2013-01-01

72

J 0.2-values by impact testing  

Microsoft Academic Search

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

F Ramsteiner

1999-01-01

73

Brain strains in vehicle impact tests.  

PubMed

The purpose of this research was to use vehicle impact test data and parametric finite element analysis to study the contribution of translational accelerations (TransAcc) and rotational accelerations (RotAcc) on strain-induced head injuries. Acceleration data were extracted from 33 non-contact vehicle crash tests conducted by the US Department of Transportation, National Highway Traffic Safety Administration. A human finite element head model was exercised using head accelerations from the nine accelerometer package placed inside the driver dummy in these tests. Three scenarios were parameterized: both TransAcc and RotAcc, only TransAcc, and only RotAcc to demonstrate the contribution of these accelerations on brain injury. Brain strains at multiple elements, cumulative strain damage, dilatation damage, and relative motion damage data were compared. Rotational accelerations contributed to more than 80% of the brain strain. Other injury metrics also supported this finding. These findings did not depend on the crash mode, peak amplitude of translational acceleration (29 to 120 g), peak amplitude of rotational acceleration (1.3 to 9.4 krad/s ( 2 ) ) or HIC (68-778). Rotational accelerations appeared to be the major cause of strain-induced brain injury. PMID:16968626

Zhang, Jiangyue; Yoganandan, Narayan; Pintar, Frank A; Gennarelli, Thomas A

2006-01-01

74

Constitutive modeling using the Taylor impact test  

SciTech Connect

The Taylor test can be conveniently divided into three fairly distinct stages: (1) initial transient behavior after impact characterized by nonlinear plastic wave propagation. (2) quasi-steady propagation of the plastic wave front. The duration of this stage is a function of specimen caliber and material. (3) terminal transient behavior, during which most of the deceleration of the undeformed section takes place. After the initial transient is complete, which varies with the strain at which the plastic wave front propagates, the motion is well behaved, in the sense that a one-dimensional analysis can be effectively applied. This paper contains such an analysis. Results are supported by an example from which the state of stress for an OFHC copper specimen is deduced.

Jones, S.E. [Univ. of Alabama, Tuscaloosa, AL (United States). Dept. of Mechanical Engineering; Maudlin, P.J. [Los Alamos National Lab., NM (United States); Foster, J.C. Jr. [Air Force Armament Lab., Eglin AFB, FL (United States)

1995-09-01

75

Impact testing of structural biological materials  

Microsoft Academic Search

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

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

76

A tensile impact test apparatus for composite materials  

Microsoft Academic Search

A tensile impact test apparatus capable of applying a pure axial tensile loading to even a highly orthotropic composite material, e.g., a unidirectionally reinforced composite, was designed and constructed. Existing impact test methods such as Charpy, Izod and plate impact induce very complex stress states, making the interpretation of results difficult. Details of the apparatus design, and instrumentation problems which

D. F. Adams; L. G. Adams

1989-01-01

77

Simulation of wheel impact test using finite element method  

Microsoft Academic Search

In order to achieve better quality, the wheel design and manufacturing use a number of wheel tests to ensure that the wheel meets the safety requirements. The impact performance of wheel is a major concern of new design wheel. The wheel impact test is intended to evaluate the impact performance of wheel, that the striker is dropped from a specified

Chia-Lung Chang; Shao-Huei Yang

2009-01-01

78

Research-tested Intervention Programs: Intervention Impact  

Cancer.gov

Intervention Impact Score Calculation Intervention impact is calculated based on population reach and intervention effect size that are rated separately and combined into a single score based on the following: Reach Score Effect Size Score Combined Intervention

79

Mark III confirmatory test program: one-third scale pool swell impact tests, Test Series 5805  

Microsoft Academic Search

A series of 51 blowdown tests was performed in support of the Mark III ; pressure suppression concept with particular emphasis on the effect of pool swell ; impact on structures located above the suppression pool. The integrated steam ; generator and drywell of the Pressure Suppression Test Facility was used to ; accelerate the water mass in the one-third

T. R. McIntyre; W. J. Bilanin; M. A. Ross; J. E. Torbeck

1975-01-01

80

46 CFR 54.05-15 - Weldment toughness tests-procedure qualifications.  

Code of Federal Regulations, 2011 CFR

...For these tests, the test plates shall be oriented with their...the V-notch normal to the plate surface. The sample weld...the notch centered in the weld metal. (2) Three specimens with...the fusion line between parent plate and weld. (The fusion...

2011-10-01

81

46 CFR 54.05-15 - Weldment toughness tests-procedure qualifications.  

Code of Federal Regulations, 2012 CFR

...For these tests, the test plates shall be oriented with their...the V-notch normal to the plate surface. The sample weld...the notch centered in the weld metal. (2) Three specimens with...the fusion line between parent plate and weld. (The fusion...

2012-10-01

82

Instrumented impact testing at high velocities  

SciTech Connect

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 these impact events, since there is evidence that a low-velocity impact will not always result in the same amount or even type of damage as a high-velocity impact. This paper provides a detailed description of the instrumented low-mass impact facility at The University of British Columbia (UBC). A gas gun is used to accelerate the instrumented projectile to impact velocities as high as 50 m/s, corresponding to an energy level of 350 J. The contact force during the impact event is measured by an incorporated load cell. The necessary mathematical operations to determine the real load-displacement curves are outlined, and the results of some impact events at different velocities are shown. 23 refs.

Delfosse, D.; Pageau, G.; Bennett, R.; Poursartip, A. (British Columbia Univ., Vancouver (Canada) Defence Research Establishment Valcartier, Courcelette (Canada))

1993-01-01

83

Instrumented impact testing at high velocities  

NASA Astrophysics Data System (ADS)

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 these impact events, since there is evidence that a low-velocity impact will not always result in the same amount or even type of damage as a high-velocity impact. This paper provides a detailed description of the instrumented low-mass impact facility at The University of British Columbia (UBC). A gas gun is used to accelerate the instrumented projectile to impact velocities as high as 50 m/s, corresponding to an energy level of 350 J. The contact force during the impact event is measured by an incorporated load cell. The necessary mathematical operations to determine the real load-displacement curves are outlined, and the results of some impact events at different velocities are shown.

Delfosse, Daniel; Pageau, Gilles; Bennett, Roger; Poursartip, Anoush

84

Influence of some test parameters on specimen loading determination methods in instrumented Charpy impact tests  

Microsoft Academic Search

This paper is devoted to the analysis of the influence of some test parameters on impact load and specimen displacement measurements in instrumented Charpy impact tests. As impact material behaviour is a multi-parameter problem, design of experiment method is used in order to organise test campaign and to assess the most influence variables. On one side, it is shown that

P Landrein; T Lorriot; L Guillaumat

2001-01-01

85

Instrumented impact testing of kenaf fiber reinforced polypropylene ...  

Treesearch

Title: Instrumented impact testing of kenaf fiber reinforced polypropylene composites: effects of temperature and composition ... chemical composition, plant fibers, temperature, influences, tensile strength, strength, durability, wood- plastic ...

86

The Impact of EFL Testing on EFL Education in Korea  

ERIC Educational Resources Information Center

The present study provides an overview of the impact of standardized EFL tests on EFL education in Korea. To achieve this goal, the paper (1) presents the status quo of EFL testing in the Korean context, (2) explores the nature of the EFL tests prevalent in the EFL testing market, and (3) investigates the overwhelming washback effects of EFL tests

Choi, Inn-Chull

2008-01-01

87

Impact testing of concrete using a drop-weight impact machine  

Microsoft Academic Search

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

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

1989-01-01

88

Repeated impact test for characterization of hard coatings  

Microsoft Academic Search

The repeated impact test is an attractive method to evaluate different properties of hard coatings serving under the conditions subjected to cyclic loads. The main parameter leading to the failure of coatings has been attributed to the contacting load. However, the dynamic impact loading is characterized in the impact wave, which is much more severe than that of static loading,

Xiaodong Zhu; Hailin Dou; Zhigang Ban; Yixiong Liu; Jiawen He

2007-01-01

89

A new oblique impact test for motorcycle helmets  

Microsoft Academic Search

A new oblique impact test for motorcycle helmets is described, simulating a fall from a motorcycle on to the road surface or the windshield of a car. An instrumented headform falls vertically to impact a horizontally moving rigid rough or deformable surface. Both the impact site on the helmet, and the vertical and horizontal velocities, can be varied, while the

P. Halldin; A. Gilchrist; N. J. Mills

2001-01-01

90

Nondestructive testing method of concrete using impact acoustics  

Microsoft Academic Search

A new nondestructive testing method for concrete using impact acoustics is investigated. Impact acoustics, which has a strong relation with the vibration of a concrete surface, can offer important information about the physical properties of concrete structures such as shapes, material properties and defects. In this paper, the relation between impact acoustics and vibration at the same surface of the

Y. Ito; T. Uomoto

1997-01-01

91

Impact properties of irradiated HT9 from the fuel duct of FFTF  

SciTech Connect

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 (DDBTT) 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 DDBTT data from different studies were compared.

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

2012-02-01

92

Impact Properties of Irradiated HT9 from the Fuel Duct of FFTF  

SciTech Connect

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 oC. 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 25J capacity machine. Irradiation lowered the upper-shelf energy (USE) and increased the transition temperatures significantly. The shift of transition temperatures 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. For the irradiated specimens, 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. The size effect was also discussed to clarify the differences in the impact data of subsize and standard specimens.

Byun, Thak Sang [ORNL; Maloy, S [Los Alamos National Laboratory (LANL); Toloczko, M [Pacific Northwest National Laboratory (PNNL); Lewis, William Daniel [ORNL

2012-01-01

93

Review of Recent Developments in Multiple Reference Impact Testing (MRIT)  

Microsoft Academic Search

\\u000a Impact testing was one of the first practical applications of the Fast Fourier Transform (FFT) technique in the late 60s.\\u000a Prior to the development of the FFT, measuring the Frequency Response Function (FRF) was limited to sinusoidal testing procedures.\\u000a The sine testing methods were slow, and required elaborate fixtures for excitation (electro-mechanical or hydraulic exciters).\\u000a Impact testing had an order

D. L. Brown; M. C. Witter

94

Multibody modelling of a side impact test apparatus  

Microsoft Academic Search

A new side impact component test apparatus has been developed to recreate, in a cost-effective, repeatable, test environment, the kinematics of the intruding door, seat, and occupant as experienced in a full-scale side impact test. In this component test, a fixture-mounted door structure, complete with inner trim, is accelerated from rest using a pneumatic ram. The occupant is seated in

R. A. Moms; J. R. Crandall; W. D. Pilkey

1999-01-01

95

Mechanics of Taylor impact testing of polycarbonate  

Microsoft Academic Search

The deformation of polymers under high-rate loading conditions is a governing factor in their use in impact-resistant applications, such as protective shields, safety glass windows and transparent armor. In this paper, Taylor impact experiments were conducted to examine the mechanical behavior of polycarbonate (PC), under conditions of high strain rate (?105s?1) and inhomogeneous deformation. High-speed photography was used to monitor

Sai Sarva; Adam D. Mulliken; Mary C. Boyce

2007-01-01

96

Design of an impact abrasion testing machine  

Microsoft Academic Search

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

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

1994-01-01

97

XDT in HTPB propellant from steel flyer plate impact tests  

Microsoft Academic Search

Several experiments simulating ground impact explosion following the command destruction of a launch vehicle have been performed using HTPB propellant samples of mass 460 to 940 kg impacted by a steel flyer plate. Impact velocities were varied from 135 m\\/s to 170 m\\/s. Strong explosions were observed at impact velocities higher than 150 m\\/s for tests of solid rocket propellant

Katsumi Tanaka; Keiichiro Noda; Yukio Hyodo; Hiroyuki Nakamura; Katsuaki Kosaka; Takashi Nakayama; Masahide Katayama; Atsushi Takeba

2000-01-01

98

Responses of side impact dummies in sled tests  

Microsoft Academic Search

Sled tests were conducted at a velocity of 6.7m\\/s using side impact dummies (SID, BioSID, ES-2, and WorldSIDp) and the resulting biomechanical responses were compared with responses from post mortem human subjects (PMHS). Initial impact conditions were with and without pelvic offset in combination with and without padding on the impacting wall. Impact forces, thoracic trauma index, chest compression, and

Narayan Yoganandan; Frank A. Pintar

2005-01-01

99

Random Decrement Signal Processing of Modal Impact Test Data  

Microsoft Academic Search

\\u000a When performing modal impact tests on mechanical systems many practioners utilize hardware based digital signal processors\\u000a to rapidly estimate average spectral properties from a set of repeated impact and response time traces. However, if the complete\\u000a set of time traces is saved as is commonly done when performing impact tests on civil structures then more generalized analysis\\u000a and triggering conditions

Rune Brincker; Anders Brandt

100

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

Microsoft Academic Search

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

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

2005-01-01

101

The Impact of EFL Testing on EFL Education in Korea  

ERIC Educational Resources Information Center

|The present study provides an overview of the impact of standardized EFL tests on EFL education in Korea. To achieve this goal, the paper (1) presents the status quo of EFL testing in the Korean context, (2) explores the nature of the EFL tests prevalent in the EFL testing market, and (3) investigates the overwhelming washback effects of EFL…

Choi, Inn-Chull

2008-01-01

102

Light-weight radioisotope heater unit (LWRHU) impact tests  

SciTech Connect

The light-weight radioisotope heater unit (LWRHU) is a {sup 238}PuO{sub 2}-fueled heat source designed to provide one thermal watt in each of various locations on a spacecraft. Los Alamos National Laboratory designed, fabricated, and safety tested the LWRHU. The heat source consists of a hot-pressed {sup 238}PuO{sub 2} fuel pellet, a Pt-30Rh vented capsule, a pyrolytic graphite insulator, and a fineweave-pierced fabric graphite aeroshell assembly. To compare the performance of the LWRHUs fabricated for the Cassini mission with the performance of those fabricated for the Galileo mission, and to determine a failure threshold, two types of impact tests were conducted. A post-reentry impact test was performed on one of 180 flight-quality units produced for the Cassini mission and a series of sequential impact tests using simulant-fueled LWRHU capsules were conducted respectively. The results showed that deformation and fuel containment of the impacted Cassini LWRHU was similar to that of a previously tested Galileo LWRHU. Both units sustained minimal deformation of the aeroshell and fueled capsule; the fuel was entirely contained by the platinum capsule. Sequential impacting, in both end-on and side-on orientations, resulted in increased damage with each subsequent impact. Sequential impacting of the LWRHU appears to result in slightly greater damage than a single impact at the final impact velocity of 50 m/s. {copyright} {ital 1998 American Institute of Physics.}

Reimus, M.A.; Rinehart, G.H.; Herrera, A.; Lopez, B.; Lynch, C.; Moniz, P. [Nuclear Materials Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

1998-01-01

103

Light-weight radioisotope heater unit (LWRHU) impact tests  

SciTech Connect

The light-weight radioisotope heater unit (LWRHU) is a {sup 238}PuO{sub 2}-fueled heat source designed to provide one thermal watt in each of various locations on a spacecraft. Los Alamos National Laboratory designed, fabricated, and safety tested the LWRHU. The heat source consists of a hot-pressed {sup 238}PuO{sub 2} fuel pellet, a Pt-30Rh vented capsule, a pyrolytic graphite insulator, and a fineweave-pierced fabric graphite aeroshell assembly. To compare the performance of the LWRHUs fabricated for the Cassini mission with the performance of those fabricated for the Galileo mission, and to determine a failure threshold, two types of impact tests were conducted. A post-reentry impact test was performed on one of 180 flight-quality units produced for the Cassini mission and a series of sequential impact tests using simulant-fueled LWRHU capsules were conducted respectively. The results showed that deformation and fuel containment of the impacted Cassini LWRHU was similar to that of a previously tested Galileo LWRHU. Both units sustained minimal deformation of the aeroshell and fueled capsule; the fuel was entirely contained by the platinum capsule. Sequential impacting, in both end-on and side-on orientations, resulted in increased damage with each subsequent impact. Sequential impacting of the LWRHU appears to result in slightly greater damage than a single impact at the final impact velocity of 50 m/s.

Reimus, M. A. H.; Rinehart, G. H.; Herrera, A.; Lopez, B.; Lynch, C.; Moniz, P. [Nuclear Materials Technology Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

1998-01-15

104

Dynamic fragmentation process in concrete under impact and spalling tests  

Microsoft Academic Search

Intense damages as scabbing on front face, spalling on rear face, radial cracks are observed in concrete structures when subjected\\u000a to the impact of a kinetic striker. To characterize the dynamic strength and damage of concretes under such loadings one may\\u000a perform spalling tests and EOI (edge-on impact) tests. Both tests have been conducted with dry and wet specimens of

P. Forquin; B. Erzar

2010-01-01

105

Numerical comparison between different strength after impact test procedures  

NASA Astrophysics Data System (ADS)

Different procedures are established to investigate the residual properties of sandwich panels after impact damage. Two used procedures for the testing of this properties are compression after impact (CAI) and 4-point bending. In this paper a numerical procedure is presented for a first prediction of the behaviour of pre-damaged sandwich specimens under different boundary conditions (or testing procedures). A sequence of impact experiments using a drop tower is performed to assess the damage tolerance of sandwich panels with aramid paper foldcores and CFRP skins. The tested impact energy range allowed to investigate a variety of damage scenarios from barely visible damages (BVID) to fibre fractures in all plies of the impacted face sheet. Additionally 4-point bending tests are performed with the panels previously damaged by impact loadings to assess the residual bending strength of these samples. The developed numerical procedure is used to reproduce these experiments (the impact as well as the 4-point bending tests). Also the same procedure is employed in an attempt to predict the behaviour of samples with the same build-up in simulated compression after impact tests.

Klaus, M.; Reimerdes, H. G.

2010-06-01

106

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

Microsoft Academic Search

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

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

107

Harsh solder joint reliability tests by impact drop and highly accelerated life test (HALT)  

Microsoft Academic Search

In this work, board level impact drop test and highly accelerated life test (HALT) were conducted on lead-free soldered assemblies. Harsh solder joint reliability testing are needed for impact drop requirements particularly for portable electronics. Highly accelerated life testing (HALT) is increasingly used for high-end workstation server systems. For drop test, the acceleration and strain were measured for clamped-clamped PCB

F. X. Che; J. H. L. Pang

2004-01-01

108

A novel impact test system for more efficient reliability testing  

Microsoft Academic Search

Portable electronic products such as mobile phones experience various loadings in their use environments but accidental drops are encountered most frequently. Over the past few years the drop reliability of electronic assemblies has been studied by means of the travelling table test apparatuses described in the JESD22-B111 drop test standard. There are, however, a few essential shortcomings related to this

Jussi Hokka; Toni T. Mattila; Jue Li; Jarmo Teeri; Jorma. K. Kivilahti

2010-01-01

109

FEA of oblique impact tests on a motorcycle helmet  

Microsoft Academic Search

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

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

2009-01-01

110

Analysis of impact energy factors in ductile materials using single particle impact tests on gas gun  

Microsoft Academic Search

Wear is surface damage that involves progressive material loss due to relative motion between the contacting surfaces. Removal of material by action of impacting particles is known as erosion. Single particle impact tests were conducted using small particles (95–100?m) and impact velocity 90ms?1. A new technique has been developed to measure the impact crater using Laser Scanning Confocal Microscope (LSCM).

A. A. Cenna; K. C. Williams; M. G. Jones

2011-01-01

111

Project Plan: Screener Readiness Test Impact Study  

National Technical Information Service (NTIS)

The Screening Company Certification Rule will evaluate screening companies' performance using Threat Image Projection (TIP). It will require individuals who have received initial screener training to pass the Screener Readiness Test (SRT) before they can ...

J. Rubinstein B. A. Klock E. C. Neiderman

2001-01-01

112

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

Microsoft Academic Search

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

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

2002-01-01

113

High impact-testing machine for elastomers investigation under impact loads  

Microsoft Academic Search

A description of a new high speed falling-dart impact machine is presented. The machine, instrumentation and also some experimental analysis of elastomers are described. Important factors influencing the impact behaviour of elastomers are impact velocity and temperature during the tests. The machine allows a velocity between 2 and 50m\\/s and temperature from ?40 to 180°C. Some testing results on TPE,

A. Söver; L. Frormann; R. Kipscholl

2009-01-01

114

Comparing drop impact test method using strain gauge measurements  

Microsoft Academic Search

In this paper, strain gauges are used to measure the dynamic response during drop impact. A set of high-speed data acquisition system is used to capture the real-time strain response of critical locations. Finite Element Modelling is used to determine where to place the strain gauges. Two board level drop impact test methods, A and B, are compared by the

Y. Liu; F. J. H. G. Kessels; Willem D. van Driel; J. A. S. van Driel; F. L. Sun; G. Q. Zhang

2009-01-01

115

Impact on BRCA1/2 Testing on Marital Relationships.  

National Technical Information Service (NTIS)

The proposed study is a prospective longitudinal examination of the impact of genetic testing for breast-ovarian cancer susceptibility on the marital relationships of women at risk as well as the impact upon the quality of life of their husbands. This stu...

S. Manne

2001-01-01

116

Full-scale aircraft impact test for evaluatioin of impact force: Part 2: Analysis of results  

SciTech Connect

For estimating the global elasto-plastic structural response of critical concrete structures subjected to an aircraft crash, the time dependent impact force of a flat rigid barrier against a normally impacting aircraft was first evaluated and then the response, to the impact force, was calculated. In this approach, a significant problem was to determine the impact force for the aircraft against a rigid target. A review of the method proposed to determine the impact forces showed that all were based on analytical methods. However, in these analytical methods, there were many assumptions and many questions remained to be answered. Because of the uncertainty involved in the analytical prediction of the impact force, a full- scale aircraft impact test was performed and an extensive suite of response measurements was obtained. In this paper, these measurements are analyzed to evaluate the impact force accurately. Also, the results were used to evaluate existing analytical methods for prediction of the impact force. 7 refs., 10 figs.

Muto, K.; Sugano, T.; Tsubota, H.; Koshika, N.; Suzuki, M.; Ohrui, S.; von Riesemann, W.A.; Bickel, D.C.; Parrish, R.L.; Tachau, R.D.M.

1989-01-01

117

Genetic Testing for Breast Cancer: Psychological and Social Impact  

MedlinePLUS

Breast cancer Basics In-Depth Multimedia Expert Answers Expert Blog Resources What's New Reprints A single copy of ... for personal, noncommercial use only. Genetic testing for breast cancer: Psychological and social impact By Mayo Clinic staff ...

118

Testing for the Impact Resistance of Ophthalmic Lenses.  

National Technical Information Service (NTIS)

The principal findings of the Optical Manufacturers Association's Research Associate Program are summarized. The limitations of the present drop ball test for impact resistance are discussed. Essentially, only a small part of the lens surface and a small ...

R. E. Berger

1976-01-01

119

LLNL small-scale drop-hammer impact sensitivity test  

SciTech Connect

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.

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

1995-01-01

120

Determination of the Fracture Toughness of a Low Alloy Steel by the Instrumented Charpy Impact Test  

Microsoft Academic Search

An attempt to establish a non-empirical relationship between the Charpy V-notch energy CVN and the fracture toughness KIc is presented. We focus our study on the lower shelf of fracture toughness and on the onset of the ductile-to-brittle transition of a A508 Cl.3 low alloy structural steel. The methodology employed is based on the `local approach'. Brittle cleavage fracture is

A. Rossoll; C. Berdin; C. Prioul

2002-01-01

121

Low Power Arcjet Test Facility Impacts.  

National Technical Information Service (NTIS)

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 perfor...

W. E. Morren P. J. Lichon

1992-01-01

122

Defense Waste Processing Facility canister impact testing  

Microsoft Academic Search

The Materials Characterization Center at Pacific Northwest Laboratory (PNL) has drop tested seven Defense Waste Processing Facility high-level waste canisters for Savannah River Laboratory (SRL) (1). The canisters were filled with simulated waste glass to \\/approximately\\/85% capacity and sealed by SRL before being shipped to PNL. Each 304L stainless steel canister was approximately 300 cm (9 ft 10 in.) long,

K. M. Olson; J. M. Alzheimer

1989-01-01

123

30 CFR 7.46 - Impact test.  

Code of Federal Regulations, 2013 CFR

...contact only the filler material or partitions between the individual cells. At the test temperature range of 65 °F -80 °F (18.3 °C-26.7 °C), apply a dynamic force of 200 ft. lbs. to the following areas using a hemispherical weight...

2013-07-01

124

Taylor impact tests and simulations of plastic bonded explosives  

NASA Astrophysics Data System (ADS)

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.

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

2012-03-01

125

Light-Weight Radioisotope Heater Unit (LWRHU) sequential impact tests  

SciTech Connect

The light-weight radioisotope heater unit (LWRHU) is a {sup 238}PuO{sub 2}-fueled heat source designed to provide one thermal watt in each of various locations on a spacecraft. Los Alamos National Laboratory designed, fabricated, and safety tested the LWRHU. The heat source consists of a hot-pressed {sup 238}PuO{sub 2} fuel pellet, a Pt-30Rh vented capsule, a pyrolytic graphite insulator, and a fineweave-pierced fabric graphite aeroshell assembly. A series of sequential impacts tests using simulant-fueled LWRHU capsules was recently conducted to determine a failure threshold. Sequential impacting, in both end-on and side-on orientations, resulted in increased damage with each subsequent impact. Although the tests were conducted until the aeroshells were sufficiently distorted to be out of dimensional specification, the simulant-fueled capsules used in these tests were not severely deformed. Sequential impacting of the LWRHU appears to result in slightly greater damage than a single impact at the final impact velocity of 50 m/s. Postimpact examination revealed that the sequentially impacted capsules were slightly more deformed and were outside of dimensional specifications.

Reimus, M.A.H.; Rinehart, G.H.

1997-08-01

126

Impact Testing of Stainless Steel Material at Cold Temperatures  

SciTech Connect

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.

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

2008-07-01

127

Semiautomated Computer-Interactive Dynamic Impact Testing System.  

National Technical Information Service (NTIS)

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 te...

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

1989-01-01

128

Impact tests of reinforced plastics at low temperatures  

Microsoft Academic Search

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

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

1982-01-01

129

Data analysis techniques for impact tests of composite materials  

Microsoft Academic Search

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

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

1994-01-01

130

Thin hard coatings fracture propagation during the impact test  

Microsoft Academic Search

One of the most significant applications of the impact test is to investigate thin hard coatings fatigue properties. Herein the test conditions and duration up to the film damage initiation, are considered in order to determine the critical stresses associated with the coating fatigue strength. Moreover, the subsequent film damage propagation is a significant mechanism as well, since it refers

K.-D. Bouzakis; A. Siganos; T. Leyendecker; G. Erkens

2004-01-01

131

Uptake and Impact of Carrier Testing for Cystic Fibrosis  

Microsoft Academic Search

The first aim of the paper is to review research into the uptake of carrier testing for cystic fibrosis and into the impact of carrier testing on self-esteem, risk perception and reproductive decisions. The second aim is to connect the most important findings to psychological theories and concepts. Thirdly, we infer practical suggestions for genetic counselling. The uptake of genetic

Marleen Decruyenaere; Gerry Evers-Kiebooms; Lieve Denayer; Myriam Welkenhuysen

1998-01-01

132

An Evaluation of Impact Wrench Vibration Emissions and Test Methods  

Microsoft Academic Search

In the interest of providing more effective evaluations of impact wrench vibration exposures and the development of improved methods for measuring vibration emissions produced by these tools, this study focused on three variables: acceleration measured at the tool surface, vibration exposure duration per test trial, and the amount of torque required to unseat the nuts following a test trial. For

THOMAS W. McDOWELL; R. G. Dong; X. Xu; D. E. Welcome; C. Warren

2008-01-01

133

Impact of Multiple-Detect Test Patterns on Product Quality  

Microsoft Academic Search

This paper presents the impact of multiple-detect test patterns on outgoing product quality. It introduces an ATPG tool that generates multiple-detect test patterns while maximizing the coverage of node-to- node bridging defects. Volume data obtained by testing a production ASIC with these new multiple- detect patterns shows increased defect screening capability and very good agreement with the bridging coverage estimated

Brady Benware; Chris Schuermyer; Sreenevasan Ranganathan; Robert Madge; Prabhu Krishnamurthy; Nagesh Tamarapalli; Kun-han Tsai; Janusz Rajski

2003-01-01

134

Responses of side impact dummies in sled tests.  

PubMed

Sled tests were conducted at a velocity of 6.7 m/s using side impact dummies (SID, BioSID, ES-2, and WorldSIDp) and the resulting biomechanical responses were compared with responses from post mortem human subjects (PMHS). Initial impact conditions were with and without pelvic offset in combination with and without padding on the impacting wall. Impact forces, thoracic trauma index, chest compression, and viscous criteria were evaluated. The probability of injury was estimated and rates of deformation were computed for each body region. Dummy responses were not always similar in terms of trend and injury criteria when compared with PMHS tests under the same initial conditions. Response variations will be of value in improving the biofidelity characteristics of dummies for crashworthiness evaluations. PMID:15784203

Yoganandan, Narayan; Pintar, Frank A

2005-05-01

135

Behavior of Stainless Steel 316L Under Impact Test  

Microsoft Academic Search

The stainless steels remain not easily replaceable taking into consideration their high mechanical characteristic (capacity\\u000a resistance, hardness and impact resistance) what their offer to be used in significant fields such as the nuclear power, the\\u000a storage of the chemical products. This work presents an experimental study of the behavior of austenitic stainless steel 316L\\u000a under the impact. The various tests

M. Benachour; A. Hadjoui; F. Z. Seriari

136

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

Microsoft Academic Search

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

Daniele Ghelli; Giangiacomo Minak

2011-01-01

137

The Impact of Personality and Test Conditions on Mathematical Test Performance  

ERIC Educational Resources Information Center

|Online and on-demand tests are increasingly used in assessment. Although the main focus has been cheating and test security (e.g., Selwyn, 2008) the cross-setting equivalence of scores as a function of contrasting test conditions is also an issue that warrants attention. In this study, the impact of environmental and cognitive distractions, as…

Hayes, Heather; Embretson, Susan E.

2013-01-01

138

Large Field Photogrammetry Techniques in Aircraft and Spacecraft Impact Testing  

Microsoft Academic Search

\\u000a The Landing and Impact Research Facility (LandIR) at NASA Langley Research Center is a 240 ft. high A-frame structure which\\u000a is used for full-scale crash testing of aircraft and rotorcraft vehicles. Because the LandIR provides a unique capability\\u000a to introduce impact velocities in the forward and vertical directions, it is also serving as the facility for landing tests\\u000a on full-scale

Justin D. Littell

139

Toughness characterization by small specimen test technique for HIPed joints of F82H steel aiming at first wall fabrication in fusion  

NASA Astrophysics Data System (ADS)

Reduced activation ferritic/martensitic steels (RAFMs), such as F82H steels, have been developed as candidates of structural materials for fusion. In the design of a fusion reactor, cooling channels are built in the first wall of the blanket. One large issue is to determine how to join rectangular tubes to thin panels to fabricate the first wall. Hot Isostatic Pressing (HIPing) is a solution to solve the issue. Because of the thin HIPed walls of the channels, the specimen size for inspection of HIPed interface is limited. In the present research, Small Specimen Test Techniques (SSTT) are screened for the destructive toughness investigation technique of HIPed F82H joints. 1/3 size Charpy V-notch impact (1/3 CVN) and small punch (SP) tests are employed for the present research. The toughness of the HIPed joints is strongly affected by various surface finishing of specimens treated previous to the HIPing. In the present research, several kinds of HIPed joints were surface finished by different methods and investigated by 1/3 CVN impact test. The HIPed F82H joints had different toughness ranging from 20% to 70% of the toughness of the F82H base metal. The SP test is also available for the investigation of toughness change by the HIPing. The sensitivity of 1/3 CVN impact test against toughness change was better than the SP test, it revealed that the SP test has some limitations.

Kishimoto, H.; Ono, T.; Sakasegawa, H.; Tanigawa, H.; Kohno, Y.; Kohyama, A.

2013-09-01

140

Fatigue Testing of Metallurgically-Bonded EBR-II Superheater Tubes  

SciTech Connect

Fatigue crack growth and impact tests were performed on 2¼Cr-1Mo steel specimens machined from ex-service Experimental Breeder Reactor – II (EBR-II) superheater duplex tubes. The tubes had been metallurgically bonded with a 100 µm thick Ni layer; the specimens incorporated this bond layer. Impact tests were performed at temperatures from –50 to 400°C; cracks propagating from the V-notch were arrested by delamination at the bond layer for all tests with one exception at –50°C. Fatigue crack growth tests were performed at room temperature in air and at 400°C in air and humid Ar; cracks were grown at varied levels of constant ?K. In all conditions the presence of the Ni bond layer was found to result in a net retardation of growth as the crack passed through the layer. The mechanism of retardation was identified as a disruption of crack planarity and uniformity after passing through the porous bond layer. Full crack arrest was only observed in a single test performed at near-threshold ?K level (12 MPa?m) at 400°C. In this case the crack tip was blunted by oxidation of the base steel at the steel-nickel interface.

T.C. Totemeier; D.M. Wachs; D.L. Porter

2008-05-01

141

West Valley Demonstration Project full-scale canister impact tests  

Microsoft Academic Search

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-m (23 ft) drop unbreached. The 10-gauge (0.125 in. wall thickness) stainless steel canisters were approximately 85%

K. F. Whittington; J. M. Alzheimer; C. E. Lutz

1995-01-01

142

Impact toughness of high strength low alloy TMT reinforcement ribbed bar  

Microsoft Academic Search

Charpy V-notch impact toughness of 600 MPa yield stress TMT rebars alloyed with copper, phosphorus, chromium and molybdenum\\u000a has been evaluated. Subsize Charpy specimens were machined from the rebar keeping the tempered martensite rim intact. The\\u000a copper-phosphorus rebar showed toughness of 35 J at room temperature. The toughness of copper-molybdenum and copper-chromium\\u000a rebars was 52 J. The lower toughness of

Bimal Kumar Panigrahi; Surendra Kumar Jain

2002-01-01

143

End-on radioisotope thermoelectric generator impact tests  

SciTech Connect

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.

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

1997-01-01

144

Dynamic analysis of one-point bend impact test  

Microsoft Academic Search

A simple 3-degrees of freedom (dof) model of the one-point test is developed using assumed mode method. The mode shape functions and the frequency equations of the cracked beam are derived from Timoshenko beam equations by treating the crack as a discontinuity in the moment of inertia. The 3-dof model is used to predict impact force and stress intensity factor

Prabhakar R. Marur

2000-01-01

145

Crack-Blunting Mechanisms in Impact Tests on Polymers  

Microsoft Academic Search

Some impact tests are described in which G_c, the fracture toughness, of three polymers was determined over a range of strain rates and temperatures. It was found that at high strain rates there was a substantial variation of G_c with rate. When this was investigated as a function of loading times, it was observed that the most likely explanation was

J. G. Williams; J. M. Hodgkinson

1981-01-01

146

Fracture mechanics considerations in the Charpy impact test  

Microsoft Academic Search

Instrumentation of the Charpy impact test permits an analysis of the data in terms of linear elastic fraeture mechanics. Measurements of time to fracture are converted to estimated crack opening displacements at fracture and thus to values of the fracture toughness parameter KC. The variation of these values with temperature shows a transition which is interpreted as a change from

G. D. Fearnehough; R. W. Nichols

1968-01-01

147

Predictive Genetic Testing for Alzheimer's Disease: Impact upon Risk Perception  

Microsoft Academic Search

The aim of this study was to determine the impact on risk perceptions of disclosing genetic test results used to estimate the risk of Alzheimer's disease (AD). Adult children (n = 149) of people with AD were randomized to one of two groups—Intervention group: lifetime risk estimates of AD based on age, gender, family history, and Apolipoprotein E (APOE) genotype;

Theresa M. Marteau; Scott Roberts; Susan LaRusse; Robert C. Green

2005-01-01

148

Predictive Genetic Testing for Alzheimer's Disease: Impact upon Risk Perception  

Microsoft Academic Search

The aim of this study was to determine the impact on risk perceptions of disclosing genetic test results used to estimate the risk of Alzheimer's disease (AD). Adult children (n= 149) of people with AD were randomized to one of two groups—Intervention group: lifetime risk estimates of AD based on age, gender, family history, and Apolipoprotein E (APOE) genotype; Control

Theresa M. Marteau; Scott Roberts; Susan LaRusse; Robert C. Green

2005-01-01

149

Simulated hail impact testing of photovoltaic solar panels  

Microsoft Academic Search

Techniques used to simulate and study the effect of hail on photovoltaic solar panels are described. Simulated hail stones (frozen ice spheres projected at terminal velocity) or steel balls were applied by air guns, gravity drop, or static loading. Tests with simulated hail and steel balls yielded different results. The impact strength of 10 commercially available flat-plate photovoltaic modules was

D. Moore; A. Wilson; R. Ross

1978-01-01

150

Low velocity impact testing and nondestructive evaluation of transparent materials  

SciTech Connect

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.

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

151

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

Microsoft Academic Search

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

Kishore; S Ramanathan; RMVGK Rao

1996-01-01

152

Influence of thermal conditioning media on Charpy specimen test temperature  

SciTech Connect

The Charpy V-notch (CVN) impact test is used extensively for determining the toughness of structural materials. Research programs in many technologies concerned with structural integrity perform such testing to obtain Charpy energy vs temperature curves. American Society for Testing and Materials Method E 23 includes rather strict requirements regarding determination and control of specimen test temperature. It specifies minimum soaking times dependent on the use of liquids or gases as the medium for thermally conditioning the specimen. The method also requires that impact of the specimen occur within 5 s removal from the conditioning medium. It does not, however, provide guidance regarding choice of conditioning media. This investigation was primarily conducted to investigate the changes in specimen temperature which occur when water is used for thermal conditioning. A standard CVN impact specimen of low-alloy steel was instrumented with surface-mounted and embedded thermocouples. Dependent on the media used, the specimen was heated or cooled to selected temperatures in the range {minus}100 to 100{degree}C using cold nitrogen gas, heated air, acetone and dry ice, methanol and dry ice, heated oil, or heated water. After temperature stabilization, the specimen was removed from the conditioning medium while the temperatures were recorded four times per second from all thermocouples using a data acquisition system and a computer. The results show that evaporative cooling causes significant changes in the specimen temperatures when water is used for conditioning. Conditioning in the other media did not result in such significant changes. The results demonstrate that, even within the guidelines of E 23, significant test temperature changes can occur which may substantially affect the Charpy impact test results if water is used for temperature conditioning. 7 refs., 11 figs.

Nanstad, R.K.; Swain, R.L.; Berggren, R.G.

1989-01-01

153

Radioisotope thermoelectric generator/thin fragment impact test  

SciTech Connect

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.

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

1998-12-31

154

Radioisotope thermoelectric generator/thin fragment impact test  

NASA Astrophysics Data System (ADS)

The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of 238Pu 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.

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

1998-01-01

155

Comparison of fracture toughness and Charpy impact properties recovery by thermal annealing of irradiated reactor pressure vessel steels  

Microsoft Academic Search

The objective of this investigation was to study the effects of thermal annealing on the recovery of the transition region toughness of reactor pressure vessel steels. The toughness was measured by Charpy V-notch impact energy and fracture initiation toughness, K{sub Jc}. The materials were A 533 grade B class 1 plate and a commercial reactor vessel submerged-arc weld irradiated at

M. A. Sokolov; D. E. McCabe; S. K. Iskander; R. K. Nanstad

1995-01-01

156

Charpy impact test results for low-activation ferritic alloys  

SciTech Connect

The objective of this work is to evaluate the shift of the ductile to brittle transition temperature (DBTT) and the reduction of the upper shelf energy (USE) due to neutron irradiation of low activation ferritic alloys. Six low activation ferritic alloys have been tested following irradiation at 365/sup 0/C to 10 dpa and compared with control specimens in order to assess the effect of irradiation on Charpy impact properties.

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

1987-05-01

157

Impact Testing on Composites Laminates and Sandwich Panels  

Microsoft Academic Search

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

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

1996-01-01

158

Impact Force Characteristics of Package-level Solder Joints Under Ball Impact Test  

Microsoft Academic Search

The ball impact test is developed as 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 intermetallics, similar to that from a board-level drop test. We investigate numerically in this paper the effect of yield stress variations of solder alloy on transient structural responses of a

Chang-Lin Yen; Yi-Shao Lai

2006-01-01

159

A semiautomated computer-interactive dynamic impact testing system  

SciTech Connect

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.

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

1989-01-01

160

Understanding the impact of genetic testing for inherited retinal dystrophy.  

PubMed

The capability of genetic technologies is expanding rapidly in the field of inherited eye disease. New genetic testing approaches will deliver a step change in the ability to diagnose and extend the possibility of targeted treatments. However, evidence is lacking about the benefits of genetic testing to support service planning. Here, we report qualitative data about retinal dystrophy families' experiences of genetic testing in United Kingdom. The data were part of a wider study examining genetic eye service provision. Twenty interviewees from families in which a causative mutation had been identified by a genetic eye clinic were recruited to the study. Fourteen interviewees had chosen to have a genetic test and five had not; one was uncertain. In-depth telephone interviews were conducted allowing a thorough exploration of interviewees' views and experiences of the benefits of genetic counselling and testing. Transcripts were analysed using thematic analysis. Both affected and unaffected interviewees expressed mainly positive views about genetic testing, highlighting benefits such as diagnostic confirmation, risk information, and better preparation for the future. Negative consequences included the burden of knowledge, moral dilemmas around reproduction, and potential impact on insurance. The offer of genetic testing was often taken up, but was felt unnecessary in some cases. Interviewees in the study reported many benefits, suggesting genetic testing should be available to this patient group. The benefits and risks identified will inform future evaluation of models of service delivery. This research was part of a wider study exploring experiences of families with retinal dystrophy. PMID:23403902

Combs, Ryan; McAllister, Marion; Payne, Katherine; Lowndes, Jo; Devery, Sophie; Webster, Andrew R; Downes, Susan M; Moore, Anthony T; Ramsden, Simon; Black, Graeme; Hall, Georgina

2013-02-13

161

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

|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,…

Wilde, Elizabeth Ty; Hollister, Robinson

162

An evaluation of impact wrench vibration emissions and test methods.  

PubMed

In the interest of providing more effective evaluations of impact wrench vibration exposures and the development of improved methods for measuring vibration emissions produced by these tools, this study focused on three variables: acceleration measured at the tool surface, vibration exposure duration per test trial, and the amount of torque required to unseat the nuts following a test trial. For this evaluation, six experienced male impact wrench operators used three samples each of five impact wrench models (four pneumatic models and one battery-powered model) in a simulated work task. The test setup and procedures were based on those provided by an International Organization for Standardization (ISO) Technical Committee overseeing the revision of ISO 8662-7. The work task involved the seating of 10 nuts onto 10 bolts mounted on steel plates. The results indicate that acceleration magnitudes vary not only by tool type but also by individual tools within a type. Thus, evaluators are cautioned against drawing conclusions based on small numbers of tools and/or tool operators. Appropriate sample sizes are suggested. It was further noted that evaluators could draw different conclusions if tool assessments are based on ISO-weighted acceleration as opposed to unweighted acceleration. As expected, vibration exposure durations varied by tool type and by test subject; duration means varied more for study participants than they did for tool types. For the 12 pneumatic tools evaluated in this study, torque varied directly with tool handle acceleration. Therefore, in order to reduce vibration exposure, tools should be selected and adjusted so that they produce no more than the needed torque for the task at hand. PMID:18212244

McDowell, Thomas W; Dong, R G; Xu, X; Welcome, D E; Warren, C

2008-01-22

163

Verification of constitutive models using the Asay Impact Test  

SciTech Connect

Accurate analysis and the ability to predict the complete response of particulate composite materials requires accurate inelastic constitutive models. However, to be of maximum utility, these inelastic models must be validated using quantifiable experimental results. The Asay Impact Test is an impact experiment that provides the evolution of the two dimensional in-plane displacement field in a specimen undergoing dynamic inelastic deformation. The experimental displacement field may be directed compared with the predicted displacement field from a candidate inelastic constitutive model. In this paper, the authors report comparisons between experimental and predicted displacement fields in the energetic particulate composite material PBX-9501 during dynamic deformation, and describe the experiment and the constitutive modeling approach.

Haberman, K.S.; Bennett, J.G.

1998-09-01

164

The Impact Hydrocode Benchmark and Validation Project: Results of Validation Tests  

Microsoft Academic Search

We present our first validation tests of a glass sphere impacting water and an aluminum sphere impacting aluminum as part of the collective validation and benchmarking effort from the impact cratering and explosion community.

E. Pierazzo; N. A. Artemieva; E. C. Baldwin; J. Cazamias; R. F. Coker; G. S. Collins; D. A. Crawford; T. Davison; K. A. Holsapple; K. R. Housen; D. G. Korycansky; K. Wünnemann

2008-01-01

165

Impact properties of irradiated HT9 from the fuel duct of FFTF  

NASA Astrophysics Data System (ADS)

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.

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

2012-02-01

166

Testing the impact attenuation of loose-fill playground surfaces  

PubMed Central

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.

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

2000-01-01

167

Model calibration and validation of an impact test simulation  

SciTech Connect

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.

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

2001-01-01

168

The inclined impact test, an efficient method to characterize coatings' cohesion and adhesion properties  

Microsoft Academic Search

The impact test, supported by its finite elements method (FEM) simulation, has been successfully used to characterize the fatigue performance of coatings. In this test, the load is exercised perpendicularly to the coated surface by a cemented carbides ball. In the inclined impact test, the successive impacts are applied on an inclined surface. In this way, the coated surfaces are

K.-D. Bouzakis; A. Asimakopoulos; N. Michailidis; S. Kompogiannis; G. Maliaris; G. Giannopoulos; E. Pavlidou; G. Erkens

2004-01-01

169

Some Recommendations for Characterization of Composite Panels by Means of Drop Tower Impact Testing  

Microsoft Academic Search

Instrumented drop tower impact-test devices have been long used for inflicting impact damage onto test specimens for damage tolerance characterization of composite panels. However, there are many considerations that need to be made regarding the test setup to avoid the inconveniences related to the acquisition and interpretation of the impact data. Because there are many advantages associated with this type

Paolo Feraboli

2006-01-01

170

Basic Research in Crashworthiness II-Frontal Car Impact Tests of Unmodified Vehicles.  

National Technical Information Service (NTIS)

The report presents results of four car-to-car head-on impact tests. The four tests involved a Ford sedan impacting a Ford, Buick, Chevrolet Nova and a Chevrolet Vega, respectively. All four tests were conducted using unmodified vehicles impacting at a no...

F. A. DuWaldt M. O. Ryder

1973-01-01

171

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

Microsoft Academic Search

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

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

1995-01-01

172

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

Microsoft Academic Search

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

Takakazu Yoshioka; Ichiro Takahashi

2008-01-01

173

IMPROVED BAR IMPACT TESTS USING A PHOTONIC DOPPLER VELOCIMETER  

SciTech Connect

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.

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

2009-08-24

174

Method of testing gear wheels in impact bending  

SciTech Connect

Chemicothermal treatment processes are widely used in engineering to improve the working lives of important components, of which the most common is nitrocementation. That process has been applied at the Volga Automobile Plant mainly to sprockets in gear transmissions, which need high hardness and wear resistance in the surfaces with relatively ductile cores. Although various forms of chemicothermal treatment are widely used, there has been no universal method of evaluating the strengths of gear wheels. Standard methods of estimating strength ({sigma}{sub u}, {sigma}{sub t}, {sigma}{sub b}, and hardness) have a major shortcoming: They can determine only the characteristics of the cores for case-hardened materials. Here we consider a method of impact bending test, which enables one to evaluate the actual strength of gear teeth.

Tikhonov, A.K.; Palagin, Y.M.

1995-05-01

175

The examination of the drop impact test method  

Microsoft Academic Search

The purpose of this study is to establish an experimental method of drop impact reliability for solder joints and an assessment method. The drop impact problem is composed by various factors. Such as, a drop impact induced flexural vibration of PCB (Printed Circuit Board), collision attitude, and dynamic fracture of solder joints. There are many methods examine impact reliability of

Qiang Yu; K. Watanabe; T. Tsurusawa; M. Shiratori; M. Kakino; N. Fujiwara

2004-01-01

176

Finite element model and validation of a surrogate crash test vehicle for impacts with roadside objects  

Microsoft Academic Search

Highway and roadside safety features are crash tested for compliance with certain safety criteria. US Federal Highway Administration (FHWA) uses a surrogate reusable test vehicle, Bogie, to conduct crash tests of roadside safety features. Bogie is intended to replace an impacting vehicle in order to reduce the cost of the test. Bogie can be configured with different crushable impact noses

Azim Eskandarian; Dhafer Marzougui; Nabih E. Bedewi

1996-01-01

177

Head and neck responses in oblique motorcycle helmet impacts: a novel laboratory test method  

Microsoft Academic Search

The dynamics of a Hybrid III dummy's head and neck in helmeted impacts using a novel oblique impact test were studied. Three impact conditions were investigated that simulated a range of motorcyclist head impacts and provided estimates of head and neck injury using published injury assessment reference values. The resultant linear and angular accelerations in the coronal plane were significantly

T. Y. Pang; K. T. Thai; A. S. McIntosh; R. Grzebieta; E. Schilter; R. Dal Nevo; G. Rechnitzer

2011-01-01

178

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

Microsoft Academic Search

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.

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

2001-01-01

179

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

Microsoft Academic Search

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

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

2007-01-01

180

The Role of Impact Testing in Characterizing the Toughness of Materials.  

National Technical Information Service (NTIS)

The objectives of fracture toughness testing are to provide information for design, screening, and acceptance of materials. Several tests are discussed in relation to an ideal design test possessing quantitativeness and generality: slow and impact-loaded ...

W. T. Matthews

1970-01-01

181

Light Airplane Crash Tests at Impact Velocities of 13 and 27 M/Sec.  

National Technical Information Service (NTIS)

Two similar general aviation airplanes were crash tested at the Langley impact dynamics research facility at velocities of 13 and 27 m/sec. Other flight parameters were held constant. The facility, instrumentation, tests specimens, and test method are bri...

E. Alfaro-Bou V. L. Vaughan

1977-01-01

182

Effects of nonstandard heat treatment temperatures on tensile and Charpy impact properties of carbon-steel casting repair welds  

SciTech Connect

This report discusses carbon steel castings which are used for a number of different components in nuclear power plants, including valve bodies and bonnets. Components are often repaired by welding processes, and both welded components and the repair welds are subjected to a variety of postweld heat treatments (PWHT) with temperatures as high as 899{degrees}C (1650{degrees}F), well above the normal 593 to 677{degrees}C (1100 to 1250{degrees}F) temperature range. The temperatures noted are above the A1 transformation temperature for the materials used for these components. A test program was conducted to investigate the potential effects of such ``nonstandard`` PWHTs on mechanical properties of carbon steel casting welds. Four weldments were fabricated, two each with the shielded-metal-arc (SMA) and flux-cored-arc (FCA) processes,with a high-carbon and low-carbon filler metal in each case. All four welds were sectioned and given simulated PWHTs at temperatures from 621 to 899{degrees}C (1150 to 1650{degrees}F) in increments of 56{degrees}C (100{degrees}F) and for times of 5, 10, 20, and 40 h at each temperature. Hardness, tensile, and Charpy V-notch (CVN) impact tests were conducted for the as-welded and heat-treated conditions.

Nanstad, R.K.; Goodwin, G.M.; Swindeman, M.J. [Oak Ridge National Lab., TN (United States)

1993-04-01

183

49 CFR 572.136 - Knees and knee impact test procedure.  

Code of Federal Regulations, 2010 CFR

...Transportation 7 2010-10-01 2010-10-01 false Knees and knee impact test procedure. 572.136 Section 572.136...Percentile Female Test Dummy, Alpha Version § 572.136 Knees and knee impact test procedure. (a) Knee...

2010-10-01

184

49 CFR 572.136 - Knees and knee impact test procedure.  

Code of Federal Regulations, 2010 CFR

...Transportation 7 2009-10-01 2009-10-01 false Knees and knee impact test procedure. 572.136 Section 572.136...Percentile Female Test Dummy, Alpha Version § 572.136 Knees and knee impact test procedure. (a) Knee...

2009-10-01

185

49 CFR 572.126 - Knees and knee impact test procedure.  

Code of Federal Regulations, 2010 CFR

...Transportation 7 2010-10-01 2010-10-01 false Knees and knee impact test procedure. 572.126 Section 572.126...Six-year-old Child Test Dummy, Beta Version § 572.126 Knees and knee impact test procedure. (a) Knee...

2010-10-01

186

49 CFR 572.126 - Knees and knee impact test procedure.  

Code of Federal Regulations, 2010 CFR

...Transportation 7 2009-10-01 2009-10-01 false Knees and knee impact test procedure. 572.126 Section 572.126...Six-year-old Child Test Dummy, Beta Version § 572.126 Knees and knee impact test procedure. (a) Knee...

2009-10-01

187

Effect of humidity on pedestrian legform impactor-to-car bumper impact test results  

Microsoft Academic Search

The effect of humidity on the measured injury criteria of the Transport Research Laboratory (TRL) legform impactor in the bumper impact test was evaluated. The following investigations were conducted in two different humidity conditions – 30% and 60% relative humidity (RH) environments. First, dynamic certification tests were conducted. Second, legform impactor-to-bumper impact tests using two sedan cars were conducted to

Yasuhiro Matsui; Shunsuke Takagi

2012-01-01

188

Effect of humidity on pedestrian legform impactor-to-car bumper impact test results  

Microsoft Academic Search

The effect of humidity on the measured injury criteria of the Transport Research Laboratory (TRL) legform impactor in the bumper impact test was evaluated. The following investigations were conducted in two different humidity conditions – 30% and 60% relative humidity (RH) environments. First, dynamic certification tests were conducted. Second, legform impactor-to-bumper impact tests using two sedan cars were conducted to

Yasuhiro Matsui; Shunsuke Takagi

2011-01-01

189

49 CFR 572.166 - Knees and knee impact test procedure.  

Code of Federal Regulations, 2011 CFR

...7 2011-10-01 2011-10-01 false Knees and knee impact test procedure. 572.166 Section 572.166 Transportation...Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and...

2011-10-01

190

49 CFR 572.166 - Knees and knee impact test procedure.  

Code of Federal Regulations, 2012 CFR

...7 2012-10-01 2012-10-01 false Knees and knee impact test procedure. 572.166 Section 572.166 Transportation...Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and...

2012-10-01

191

Results of crack-arrest tests on two irradiated high-copper welds  

SciTech Connect

The objective of this study was to determine the effect of neutron irradiation on the shift and shape of the lower-bound curve to crack-arrest data. Two submerged-arc welds with copper contents of 0.23 and 0.31 wt % were commercially fabricated in 220-mm-thick plate. Crack-arrest specimens fabricated from these welds were irradiated at a nominal temperature of 288{degree}C to an average fluence of 1.9 {times} 10{sup 19} neutrons/cm{sup 2} (>1 MeV). Evaluation of the results shows that the neutron-irradiation-induced crack-arrest toughness temperature shift is about the same as the Charpy V-notch impact temperature shift at the 41-J energy level. The shape of the lower-bound curves (for the range of test temperatures covered) did not seem to have been altered by irradiation compared to those of the ASME K{sub Ia} curve. 9 refs., 21 figs., 10 tabs.

Iskander, S.K.; Corwin, W.R.; Nanstead, R.K. (Oak Ridge National Lab., TN (USA))

1990-12-01

192

Evaluation of cylinder-impact test data for constitutive model constants  

Microsoft Academic Search

This paper examines the usefulness of cylinder-impact test data to determine constants for various computational constitutive models. The Johnson–Cook and Zerilli–Armstrong constitutive models are evaluated by comparing model predictions to tension, torsion, and cylinder-impact test data. Then the cylinder-impact test data are used to determine constitutive model constants for various forms of these models. Under bounded conditions of strains and

Gordon R. Johnson; Tim J. Holmquist

1988-01-01

193

Full-scale aircraft impact test for evaluatioin of impact force: Part 2: Analysis of results  

Microsoft Academic Search

For estimating the global elasto-plastic structural response of critical concrete structures subjected to an aircraft crash, the time dependent impact force of a flat rigid barrier against a normally impacting aircraft was first evaluated and then the response, to the impact force, was calculated. In this approach, a significant problem was to determine the impact force for the aircraft against

K. Muto; T. Sugano; H. Tsubota; N. Koshika; M. Suzuki; S. Ohrui; W. A. von Riesemann; D. C. Bickel; R. L. Parrish; R. D. M. Tachau

1989-01-01

194

Inverse Analysis of Impact Test Data: Experimental Study on Polymeric Materials Displaying Brittle Behaviour  

NASA Astrophysics Data System (ADS)

This paper deals with the influence of the testing equipment on impact load measurements. A previously developed method of analysis and processing of the experimental data based on a refined analogical model of the impact event and inverse problem techniques is used. This method makes it possible to obtain the mechanical response of the material, notwithstanding the disturbance of the dynamic effects associated to the test. Results from tests carried out both on falling weight and swing pendulum instrumented testing machines are compared. It is shown that this method can give an accurate estimation of the actual bending force in impact testing independent of the testing equipment.

Pettarin, Valeria; Frontini, Patricia; Eliçabe, Guillermo; Rink, Marta; Pavan, Andrea

2004-09-01

195

Ethical Dilemmas in Testing for Late Onset Conditions: Reactions to Testing and Perceived Impact on Other Family Members  

Microsoft Academic Search

This paper examines some of the ethical dilemmas that arise when testing for the late onset, untreatable condition of Huntington disease (HD) specifically now that technology allows us to test younger generations of the family for the mutant gene. Drawing on interview data from families with Huntington disease, the reactions to testing and perceived impact on other family members are

Elizabeth Chapman

2002-01-01

196

Testing mechanistic modeling to assess impacts of biomass removal  

Microsoft Academic Search

The impacts that stand treatments have on carbon, nitrogen and water cycles is a key question relating the sustainability of forests to individual forest management decisions. While the response of the above ground carbon cycle may be relatively easy to measure and is well understood, e.g. volume growth response due to thinning, the impact of stand treatment and different harvesting

Katarína Mergani?ová; Stephan A. Pietsch; Hubert Hasenauer

2005-01-01

197

MPM VALIDATION: SPHERE-CYLINDER IMPACT TESTS: ENERGY BALANCE  

Microsoft Academic Search

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

B. Banerjee

198

Analyses of Full-Scale Tank Car Shell Impact Tests.  

National Technical Information Service (NTIS)

This paper describes analyses of a railroad tank car impacted at its side by a ram car with a rigid punch. This generalized collision, referred to as a shell impact, is examined using nonlinear finite element analysis (FEA) and threedimensional (3-D) coll...

D. Y. Jeong H. Yu J. E. Gordon M. Priante Y. H. Tang

2007-01-01

199

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

Microsoft Academic Search

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

Yanxiong Liu; Benjamin Liaw

2009-01-01

200

Effectiveness of cargo barriers to protect front seat occupants in rear impacts - crash test evaluation  

Microsoft Academic Search

although cargo barriers have been well developed for providing cargo restraint in frontal impacts, the effect of load and restraint systems subjected to rear impacts has not been subjected to the same performance evaluation. This paper examines this issue and presents the results from a rear impact crash test carried out on a telecommunication service vehicle fitted with storage shelving

G. Rechnitzer; R. Grzebieta; G. Brown; R. Schuster

2001-01-01

201

KRASH Dynamics Analysis Modeling - Transport Airplane Controlled Impact Demonstration Test. Revision.  

National Technical Information Service (NTIS)

A transport airplane Controlled Impact Demonstration (CID) test is analyzed with program KRASH. Prior to modeling the test condition, supporting analysis of both narrow-body and wide-body transport airplane frame segments were modeled with KRASH and compa...

G. Wittlin B. LaBarge

1986-01-01

202

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

National Technical Information Service (NTIS)

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 hyper...

A. Finchum B. Suggs M. Nehls N. M. Lowrey P. Gray W. Young

2011-01-01

203

Passenger Rail Two-Car Impact Test Volume 2: Summary of Occupant Protection Program.  

National Technical Information Service (NTIS)

Two full-scale impact tests of rail cars fitted with seat/occupant experiments were conducted at the Federal Railroad Administration's Transportation Technology Center located in Pueblo, Colorado. The first test was conducted on November 16, 1999, with a ...

C. VanIngen-Dunn

2002-01-01

204

Hybrid III anthropomorphic test device (ATD) response to head impacts and potential implications for athletic headgear testing.  

PubMed

The Hybrid III 50th percentile male anthropomorphic test device (ATD) is the most widely used human impact testing surrogate and has historically been used in automotive or military testing. More recently, this ATD is finding use in applications evaluating athletic helmet protectivity, quantifying head impact dosage and estimating injury risk. But ATD head-neck response has not been quantified in omnidirectional athletic-type head impacts absent axial preload. It is probable that headgear injury reduction that can be quantified in a laboratory, including in American football, boxing, hockey, lacrosse and soccer, is related to a number of interrelated kinetic and kinematic factors, such as head center of gravity linear acceleration, head angular acceleration, head angular velocity, occipito-cervical mechanics and neck stiffness. Therefore, we characterized ATD head-neck dynamic response to direct head impacts in a series of front, oblique front and lateral head impacts. Key findings were: (1) impacts producing highest ATD resultant center of gravity linear acceleration resulted in the lowest resultant occipito-cervical spine bending moment/force. (2) Resultant ATD head angular velocity and angular acceleration did not appear coupled to impact direction at lower impact energy levels; these parameters were coupled at higher energy levels. (3) The ATD had progressively increasing occipito-cervical stiffness in extension, torsion and lateral bending, respectively. Because the ATD neck influenced head and neck impact dosage parameters, testing agencies, manufacturers and researchers should consider using the Hybrid III head form attached to a neck as a means to quantify head and neck injury risks as opposed to systems that do not utilize a neck. This heightened understanding of Hybrid III ATD head-neck response, and consideration of order of stiffest axes in the lateral, oblique and extension directions, respectively, should aid in the development of head and neck injury impact testing standards. PMID:22664692

Bartsch, Adam; Benzel, Edward; Miele, Vincent; Morr, Douglas; Prakash, Vikas

2012-03-03

205

A numerical approach towards the correlation between ball impact test and drop reliability  

Microsoft Academic Search

The ball impact test is developed as 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 for solder joints of nine

Chang-Lin Yeh; Yi-Shao Lai

2006-01-01

206

Insights into correlation between board-level drop reliability and package-level ball impact test  

Microsoft Academic Search

The ball impact test is developed as 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 for solder joints of different

Chang-Lin Yeh; Yi-Shao Lai

2006-01-01

207

Experimental and numerical analysis of Al6063 duralumin using Taylor impact test  

NASA Astrophysics Data System (ADS)

The paper presents results of experimental and numerical analysis of dynamic behaviour Al6063 duralumin. Dynamical experiments were made using Taylor impact test. Experimental results at next step of study were used in numerical analyses of dynamic yield stress of tested material and model parameters of the Johnson-Cook constitutive equation. The main aim of this analysis is to find out dynamical properties of Al6063 duralumin tested in Taylor impact test.

Kruszka, L.; Anaszewicz, ?.; Janiszewski, J.; Gr?zka, M.

2012-08-01

208

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

SciTech Connect

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.

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

1981-10-01

209

Flexural Strength of Reinforced Microconcrete in Static and Impact Tests.  

National Technical Information Service (NTIS)

The final report on this investigation addresses these objectives: the static resistance of slabs with varying amounts of reinforcement; the development of yield line patterns; the dynamic resistance of the slabs due to impact loading; relationship betwee...

T. E. Glynn M. Z. Al-Salihi R. J. Meagher

1978-01-01

210

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

Microsoft Academic Search

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

Yanxiong Liu; Benjamin Liaw

2009-01-01

211

Determination of anisotropy in impact toughness of aluminium alloy 2024 T3 plate  

NASA Astrophysics Data System (ADS)

The research was aimed to quantify the existence of anisotropy in fracture toughness of aluminium alloy 2024 T3 plate (used in aircraft structural members). It was further needed to establish the direction in which the fracture toughness of aluminium alloy 2024 T3 plate is maximum and minimum. This could help ascertain the structural integrity of aircraft structural components; also while designing new components, the knowledge of variation in toughness with respect to direction helps in economizing dead weight of the aircraft. In this research, pursued at the College of Aeronautical Engineering, the anisotropy in toughness of aluminium alloy 2024 T3 plate was analysed using the Charpy V-notch impact toughness test. The effect of specimen orientation on the impact toughness values of the alloy was investigated and compared with known results to verify the reliability of the work and to ascertain the extent of anisotropy in fracture toughness of the said alloy. Charpy impact tests were carried out on ASTM E 23 standard specimens machined at a reference laboratory at room temperature (23° C +/- 2° C). Four different specimen orientations analysed for the purpose of this study were L-S, L-T, T-S and T-L directions. Subsequently, the results obtained at the research centre were then analysed and correlated with morphology of microstructure of the material to establish the reliability of the experimental results. Moreover, an analysis was also done to cater for the possible errors that could affect the fracture toughness values obtained from experimental results. It was concluded that the T-S orientation of the plate had maximum toughness, whereas, minimum toughness was observed in L-T direction.

Siddiqui, M. H.; Hashmi, F.; Junaid, A.

212

Exobiology: Laboratory tests of the impact related aspects of Panspermia  

NASA Astrophysics Data System (ADS)

The idea that life began elsewhere and then naturally migrated to the Earth is known as Panspermia. One such possibility is that life is carried on objects (meteorites, comets and dust) that arrive at the Earth. The life (bacteria) is then presumed to survive the sudden deceleration and impact, and then subsequently develop here on Earth. This step, the survivability of bacteria during the deceleration typical of an object arriving at Earth from space, is studied in this paper. To this end a two-stage light gas gun was used to fire projectiles coated with bacteria into a variety of targets at impact speeds of 3.8 to 4.9 km s-1. Targets used were rock, glass, metal and aerogel (density 100 kg m-3). Various techniques were used to search for bacteria that had transferred to the target material during the impact. These included taking cultures from the target crater and ejecta, and use of fluorescent dyes to mark sites of live bacteria. So far only one sample has shown a signal for bacteria surviving an impact. This was for bacteria cultured from the ejecta spalled from a rock surface during an impact. However, this result needs to be repeated before any firm claims can be made for bacteria surviving a hypervelocity impact event.

Burchell, M. J.; Shrine, N. R. G.; Bunch, A.; Zarnecki, J. C.

213

Impact test of a crash-energy management passenger rail car  

Microsoft Academic Search

On December 3, 2003, a single-car impact test was conducted to assess the crashworthiness performance of a modified passenger rail car. A coach car retrofitted with a crash energy management (CEM) end structure impacted a fixed barrier at approximately 35 mph. This speed is just beyond the capabilities of current equipment to protect the occupants. The test vehicle was instrumented

Karina Jacobsen; David Tyrell; Benjamin Perlman

2004-01-01

214

16 CFR Figure 1 to Subpart A of... - Glass Impact Test Structure  

Code of Federal Regulations, 2013 CFR

...Commercial Practices 2 2013-01-01 2013-01-01 false Glass Impact Test Structure 1 Figure 1 to Subpart A of Part 1201...Subpt. A, Fig. 1 Figure 1 to Subpart A of Part 1201âGlass Impact Test Structure...

2013-01-01

215

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

Microsoft Academic Search

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

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

1973-01-01

216

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

Microsoft Academic Search

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

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

1981-01-01

217

A simplified method for the impact test of beams using a pseudo-dynamic (PSD) process  

Microsoft Academic Search

The impact test in structural parts for dynamic applications is an essential procedure for their certification in the presence of time dependent loads. In the case of beam elements, either built with one material or as an assembly of different material members joined with recent developed bonding techniques, an impact test is of leading importance, once the dynamic resistance of

Francisco J. Q. Melo; Joaquim A. O. Carneiro; Cassilda L. Tavares; Pedro P. Camanho; Paulo T. de Castro

2006-01-01

218

Specimen loading determined by displacement measurement in instrumented Charpy impact test  

Microsoft Academic Search

An experimental method based on the specimen displacement measurement with a commercially available laser sensor is proposed in order to determine the actual specimen loading in instrumented impact test. The prediction resulting from this approach is compared with results deduced from dynamic analysis of impact tests with mass-spring model.

T Lorriot

2000-01-01

219

Ductile Damage Prediction in Taylor Impact Cylinder Test Using CDM Approach  

Microsoft Academic Search

Taylor cylinder impact test has been initially proposed as a potential testing technique to measure dynamic effect on material yield strength. Today, this technique represents an interesting benchmark case for constitutive and damage model performance verification. In this study, an extensive numerical investigation, using both finite element code and Lagrangian hydro-code, has been performed on standard Taylor impact cylinder configuration

A. Ruggiero; N. Bonora

2004-01-01

220

Impact fuze testing at 3000 m/sec employing explosively accelerating plates  

SciTech Connect

The Explosives Testing Division at Sandia has developed a method of simulating a re-entry vehicle impacting the ground. The purpose of the simulation is to evaluate different fusing concepts. The design and operation of this impact testing facility are described.

Gill, W.

1981-01-01

221

Rail Impact and Tiedown Tests of the M373A2 Electronic Van Semitrailer.  

National Technical Information Service (NTIS)

The U.S. Army Defense Ammunition Center and School was tasked by U.S. Army Tank-Automotive Command (TACOM) to rail impact test the M373A2 Electronic Van Semitrailer. In addition to rail impact testing, the six tiedown and four slinging provisions were tes...

A. C. McIntosh

1990-01-01

222

Impact Dynamics Research Facility for Full-Scale Aircraft Crash Testing.  

National Technical Information Service (NTIS)

An impact dynamics research facility (IDRF) was developed to crash test full-scale general aviation aircraft under free-flight test conditions. The aircraft are crashed into the impact surface as free bodies; a pendulum swing method is used to obtain desi...

V. L. J. Vaughan E. Alfaro-bou

1976-01-01

223

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

ERIC Educational Resources Information Center

|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…

Schochet, Peter Z.

2008-01-01

224

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

Microsoft Academic Search

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

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

2009-01-01

225

High velocity impact test of a C-Mn steel and inertia effect  

Microsoft Academic Search

The fracture toughness of a C-Mn steel and relevant inertia effect in a high velocity impact test were investigated. The inertia force causes oscillations in the force-time curves in impact testing which can be evened up by smoothing the peaks and valleys on the curves. When the impact velocity is in excess of 5 m\\/s, an unusual stress pulse is

Yongning Liu; Huijiu Zhou

1994-01-01

226

Anonymous HIV testing: the impact of availability on demand in Arizona.  

PubMed Central

The purpose of this study was to evaluate the impact of anonymous testing availability on human immunodeficiency virus (HIV) test demand in Arizona. Testing patterns before and after the introduction of anonymous testing were compared. Client knowledge of new test policy and delay in testing until an anonymous option was available were assessed. Test numbers among men who have sex with men showed a statistically significant increase after introduction of an anonymous testing option. Arizona continues to maintain anonymous testing availability. Public health agencies should consider how test policy may influence people's HIV test decisions.

Hirano, D; Gellert, G A; Fleming, K; Boyd, D; Englender, S J; Hawks, H

1994-01-01

227

Soft Soil Impact Testing and Simulation of Aerospace Structures  

Microsoft Academic Search

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,

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

228

Cycom 977-2 Composite Material: Impact Test Results (workshop presentation).  

National Technical Information Service (NTIS)

Contents include the following: Ambient (13A) tests of Cycom 977-2 impact characteristics by the Brucenton and statistical method at MSFC and WSTF. Repeat (13A) tests of tested Cycom from phase I at MSFC to expended testing statistical database. Conduct h...

C. Engle S. Herald C. Watkins

2005-01-01

229

Impact and Penetration Tests of Portland Cement Concrete.  

National Technical Information Service (NTIS)

Tests using the Swiss Rebound Hammer and Windsor Probe Test System were made on concrete slabs and cylinders made with three coarse aggregates, one mortar, two maximum sizes of aggregate, and at four ages, and were compared with compressive strength tests...

H. T. Arni

1972-01-01

230

Impact test characterization of carbon-carbon composites for the thermoelectric space power system  

SciTech Connect

Thirty-eight unique carbon-carbon composite materials of cylindrical architecture were fabricated by commercial vendors for evaluation as alternative impact shell materials for the modular heat source of the thermoelectric space power system. Characterization of these materials included gas gun impact tests where cylindrical specimens containing a mass simulant were fired at 55 m/s to impact a target instrumented to measure force. The force versus time output was analyzed to determine: peak force, acceleration, velocity, and displacement. All impact tests exhibited an equivalence between preimpact momentum and measured impulse. In addition, energy was conserved based on a comparison of preimpact kinetic energy and measured work. Impact test results showed that the currently specified material provided impact energy absorption comparable to the best alternatives considered to date.

Romanoski, G.R.; Pih, Hui

1995-12-31

231

Exobiology: Laboratory tests of the impact related aspects of Panspermia  

Microsoft Academic Search

The idea that life began elsewhere and then naturally migrated to the Earth is known as Panspermia. One such possibility is that life is carried on objects (meteorites, comets and dust) that arrive at the Earth. The life (bacteria) is then presumed to survive the sudden deceleration and impact, and then subsequently develop here on Earth. This step, the survivability

M. Burchell; N. Shrine; A. Bunch; J. Zarnecki

232

ROTARY WING AIRCRAFT WATER IMPACT TEST AND ANALYSES CORRELATION  

Microsoft Academic Search

The Naval Air Warfare Center, Aircraft Division (NAWCAD) in cooperation with the Federal Aviation Administration (FAA) is sponsoring a Small Business Innovation Research (SBIR) Phase II program to investigate water impact dynamics relevant to DOD, DOT and industry. One of the primary objectives of the program is to develop analytical tools that can be used to facilitate the process of

Gil Wittlin; Mike Schultz; Michael R. Smith; Bell Helicopter

2000-01-01

233

Model calibration and validation of an impact test simulation  

Microsoft Academic Search

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.

F. M. Hemez; A. C. Wilson; G. N. Havrilla

2001-01-01

234

The Effect of Test Selection on Title I Project Impact.  

ERIC Educational Resources Information Center

|An alternative is proposed to the legally required uniform procedures and criteria for reporting the results of Elementary Secondary Education Act Title I projects. It is suggested that Congress is unlikely to respond to nationwide impact data on the effectiveness of Title I even when such data are available. It is further proposed that the RMC…

Jaeger, Richard M.

235

Testing Assumptions: The Impact of Two Study Abroad Program Models  

ERIC Educational Resources Information Center

|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…

Norris, Emily Mohajeri; Dwyer, Mary M.

2005-01-01

236

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

SciTech Connect

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.

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

1997-04-01

237

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

SciTech Connect

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.

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

1994-09-01

238

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

NASA Astrophysics Data System (ADS)

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 x 5.0 x 25.4 mm) and third-size (3.33 x 3.33 x 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 -40 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.

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

239

Superior Charpy impact properties of ODS ferritic steel irradiated in JOYO  

Microsoft Academic Search

The effect of neutron irradiation on Charpy impact properties of an ODS ferritic steel developed by PNC was studied. The miniaturized Charpy V-notch (MCVN) specimens (1.5×1.5×20 mm) of two orientations (longitudinal, called 1DS-L, and transverse, 1DS-T) were irradiated to fluence levels of (0.3–3.8)×1026 n\\/m2 (En>0.1 MeV) between 646 and 845 K in JOYO. MCVN specimens before and after the irradiation

T. Kuwabara; H Kurishita; S Ukai; M Narui; S Mizuta; M Yamazaki; H Kayano

1998-01-01

240

The behavior of notched bend specimens in impact testing  

Microsoft Academic Search

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

W. Böhme; J. F. Kalthoff

1982-01-01

241

Testing and simulation of composite laminates under impact loading  

Microsoft Academic Search

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

Xinglai Dang

2000-01-01

242

Full-scale impact tests of simulated high-level waste canisters  

SciTech Connect

Full-scale impact tests of simulated high-level waste canisters at PNL were carried out in 1977 and 1981. In the first series of tests, cannisters were dropped from heights ranging from 6m to 32m from a crane onto a specially constructed test pad of steel plate set into a reinforced concrete mass. The canister impacts were recorded with both video and a high speed camera. The purpose of the tests was to determine the post-impact integrity of various canister designs. In the second series of tests, 6 canisters were dropped from a 9m height to determine the performance of the PNL Twist-Lock fill closure design and SRL fill/closure design. Five of the canisters were glass filled while the sixth contained glass marbles in a lead matrix. Impacted-glass data has led to empirical correlations useful in predicting glass fragmentation for evaluating the consequences of possible accidents.

Slate, S.C.

1982-02-01

243

The impact of genetic testing on complex diseases  

Microsoft Academic Search

Objective: Wide applications for genetic testing in the clinical care of complex diseases have been discussed. However, it has never been quanti- fied to what extent genetic testing could eventually be useful in the clinical care of common disorders. We aimed to quantify the theoretically possible utilization in common ischemic stroke, an example of a complex disease. Methods: We computed

M. J. E. van Rijn; C. M. van Duijn; A. J. C. Slooter

2005-01-01

244

Soft Soil Impact Testing and Simulation of Aerospace Structures.  

National Technical Information Service (NTIS)

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 t...

E. L. Fasanella K. E. Jackson S. Kellas

2008-01-01

245

The Woodcock Reading Mastery Test: Impact of Normative Changes  

ERIC Educational Resources Information Center

|This study examined the magnitude of differences in standard scores, convergent validity, and concurrent validity when an individual's performance was gauged using the revised and the normative update (Woodcock, 1998) editions of the Woodcock Reading Mastery Test in which the actual test items remained identical but norms have been updated. From…

Pae, Hye Kyeong; Wise, Justin C.; Cirino, Paul T.; Sevcik, Rose A.; Lovett, Maureen W.; Wolf, Maryanne; Morris, Robin D.

2005-01-01

246

The Impact of a National Test at the State Level.  

ERIC Educational Resources Information Center

In recent months the idea of a single national test seems to have lost some of its momentum, while use of national standards to which voluntary regional or state tests would be indexed seems to have gained support. Nationally, there does not seem to be any organized attempt to fuse the national education goals into the state process beyond the…

Pipho, Chris

247

Impact of Inclusion or Exclusion of Repeaters on Test Equating  

ERIC Educational Resources Information Center

|This study examined the effect of including or excluding repeaters on the equating process and results. New forms of two tests were equated to their respective old forms using either all examinees or only the first timer examinees in the new form sample. Results showed that for both tests used in this study, including or excluding repeaters in…

Puhan, Gautam

2011-01-01

248

The cultural impact of the 'AIDS' test: the American experience.  

PubMed

In March 1985 an ELISA test for serum antibodies to human T-cell leukemia/lymphotropic virus type III (HTLV-III) was licensed for use in screening commercial blood products. Controversy over the appropriate use and interpretation of this test continues, and some public health officials in the United States have advocated different counselling strategies for high and low risk individuals with the same test results. The response to AIDS illustrates that contagion has a social definition, even in the context of Western scientific medicine. PMID:3639542

McCombie, S C

1986-01-01

249

Measurement of Low Level Explosives Reaction in Gauged Multi-dimensional Steven Impact Tests  

NASA Astrophysics Data System (ADS)

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 mus 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.

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

2002-07-01

250

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...

251

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

Microsoft Academic Search

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

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

2001-01-01

252

Tensile and impact testing of an HFBR (High Flux Beam Reactor) control rod follower  

Microsoft Academic Search

The Materials Technology Group of the Department of Nuclear Energy (DNE) at Brookhaven National Laboratory (BNL) undertook a program to machine and test specimens from a control rod follower from the High Flux Beam Reactor (HFBR). Tensile and Charpy impact specimens were machined and tested from non-irradiated aluminum alloys in addition to irradiated 6061-T6 from the HFBR. The tensile test

C. J. Czajkowski; M. H. Schuster; T. C. Roberts; L. W. Milian

1989-01-01

253

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

Microsoft Academic Search

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

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

2001-01-01

254

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

ERIC Educational Resources Information Center

|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…

Zhang, Jinming

2012-01-01

255

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

Microsoft Academic Search

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

L. S Sutherland; C Guedes Soares

1999-01-01

256

Characterization of thin metallurgical coating systems by repetitive inclined impact test in dry condition  

Microsoft Academic Search

This study evaluates the effectiveness of a non-lubricated repetitive inclined impact test to differentiate the fatigue behavior of thin tribological coatings. Three coatings were studied. One is W-diamond-like carbon (DLC) and the other two are Cr-DLC made from different deposition recipes. These coatings display unique impact failure curves. The impact failure curve, analogous to the ‘S–N’ curve (a semi-log plot

Elmer S. Zanoria; Larry E. Seitzman

2004-01-01

257

Impact, puncture, and thermal testing of TRUPACT-I  

Microsoft Academic Search

The Transuranic Package Transporter (TRUPACT-I) is a packaging developed by the US Department of Energy (DOE) for transporting contact-handled transuranic waste (CH-TRU) in the USA. A full-scale prototype was built and subjected to a series of drop, puncture, and thermal tests to evaluate the package's resistance to normal handling and hypothetical accident conditions. A thermal redesign and component test program

L. E. Romesberg; M. L. Hudson

1986-01-01

258

The cultural impact of the 'AIDS' test: The American experience  

Microsoft Academic Search

In March 1985 an ELISA test for serum antibodies to human T-cell leukemia\\/lymphotropic virus type III (HTLV-III) was licensed for use in screening commercial blood products. Controversy over the appropriate use and interpretation of this test continues, and some public health officials in the United States have advocated different counselling strategies for high and low risk individuals with the same

S. C. McCombie

1986-01-01

259

The impact of prepregnancy obesity on children's cognitive test scores.  

PubMed

To examine the association between maternal prepregnancy obesity and cognitive test scores of children at early primary school age. A descriptive observational design was used. Study subjects consist of 3,412 US children aged 60-83 months from the National Longitudinal Survey of Youth 1979 Mother and Child Survey. Cognitive test scores using the Peabody Individual Achievement Test reading recognition and mathematics tests were used as the outcomes of interest. Association with maternal prepregnancy obesity was examined using the ordinary least square regression controlling for intrauterine, family background, maternal and child factors. Children of obese women had 3 points (0.23 SD units) lower peabody individual achievement test (PIAT) reading recognition score (p = 0.007), and 2 points (0.16 SD units) lower PIAT mathematics scores (p < 0.0001), holding all other factors constant. As expected, cognitive test score was associated with stimulating home environment (reading: ? = 0.15, p < 0.0001, and math: ? = 0.15, p < 0.0001), household income (reading: ? = 0.03, p = 0.02 and math: ? = 0.04, p = 0.004), maternal education (reading: ? = 0.42, p = 0.0005, and math: ? = 0.32, p = 0.008), and maternal cognitive skills (reading: ? = 0.11, p < 0.0001, and math: ? = 0.09, p < 0.0001). There was a significant association between maternal prepregnancy obesity and child cognitive test scores that could not be explained by other intrauterine, family background, maternal, and child factors. Children who live in disadvantaged postnatal environments may be most affected by the effects of maternal prepregnancy obesity. Replications of the current study using different cohorts are warranted to confirm the association between maternal prepregnancy obesity and child cognitive test scores. PMID:22350633

Tanda, Rika; Salsberry, Pamela J; Reagan, Patricia B; Fang, Muriel Z

2013-02-01

260

Prognostic impact of stress testing in coronary artery disease  

SciTech Connect

Observational data prospectively collected permit the examination of a complex set of decisions, including the decision not to perform any stress testing. Patients with or without previous myocardial infarction admitted for coronary evaluation and not submitted to any stress testing because of clinical reasons are at a higher risk for subsequent death. For prognostication, no test has been better validated than exercise electrocardiography: it can identify patients at low and high risk for future cardiac events among those without symptoms, with typical chest pain, and with previous myocardial infarction. In patients with triple-vessel disease, the results of exercise also allow those at low and high risk to be recognized. Both exercise radionuclide angiography and {sup 201}Tl scintigraphy (the latter in larger patient populations) have also demonstrated significant prognostic value on patients with or without previous myocardial infarction. Neither one has shown superiority to the other in prognostication. So far, they have been considered the only viable alternatives to exercise electrocardiography stress testing for diagnosis and prognostication. However, their costs limit their extensive application. Preliminary data suggest that intravenous dipyridamole echocardiography can be used for both diagnosis and prognostication of coronary artery disease; moreover, the prognostic information derived from dipyridamole echocardiography testing seems independent of and additive to that provided by exercise electrocardiography. Further prospective studies on larger patient populations are needed to better define the prognostic value of dipyridamole echocardiography testing.47 references.

Severi, S.; Michelassi, C. (CNR Clinical Physiology Institute, Pisa, (Italy))

1991-05-01

261

SINGLE PARTICLE IMPACT BREAKAGE CHARACTERIZATION OF MATERIALS BY DROP WEIGHT TESTING  

Microsoft Academic Search

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

Ömürden GENÇ; Levent ERGÜN; Hakan BENZER

2004-01-01

262

The effects of response features on failure modes of board level drop impact test  

Microsoft Academic Search

Portable electronic products are getting popular during last decade. One of the most common failures for a mobile device is related to the accidental drop impact during daily usage. In this paper, responses data of PCB were measured during drop impact; loading features are analyzed with response data; actual drop tests were carried out to obtained actual drop failure data;

Y. Liu; F. L. Sun; F. J. H. D. Kessels; W. D. van Driel; G. Q. Zhang

2010-01-01

263

Inverse Analysis of Impact Test Data: Experimental Study on Polymeric Materials Displaying Brittle Behaviour  

Microsoft Academic Search

This paper deals with the influence of the testing equipment on impact load measurements. A previously developed method of analysis and processing of the experimental data based on a refined analogical model of the impact event and inverse problem techniques is used. This method makes it possible to obtain the mechanical response of the material, notwithstanding the disturbance of the

Valeria Pettarin; Patricia Frontini; Guillermo Eliçabe; Marta Rink; Andrea Pavan

2004-01-01

264

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

Microsoft Academic Search

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),

J. Harding; L. M. Welsh

1983-01-01

265

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

Microsoft Academic Search

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

Leonardo D'Acquisto; Roberto Montanini

266

Dynamic Effects on Mechanical Characteristics of Composite Plates Submitted to Impact Tests  

Microsoft Academic Search

The present work deals with the behaviour of composite material plates submitted to impact loading conditions. The considered\\u000a composite material consists of long fibers in polymeric resin. Different stacking sequences and different plate thickness\\u000a are considered. Impact tests are performed according to the ASTM 3029 standard using our instrumented free-fall drop dart\\u000a testing machine, that allows to acquire the dart

G. Belingardi; M. P. Cavatorta; D. S. Paolino

267

Improving Contact-Friction Conditions in Dynamic Simulations: ~pplication to the Taylor Impact Test  

Microsoft Academic Search

The aim of this work is to test new contact-friction modelling by means of the elastoplastic Taylor impact-test. The contact-impact Lagrange multiplier method is developped in a dynamic explicit finite element frame. It allows the continuity of the contact conditions without the definition of any shock stiffness. This technique couples the calculation of the contact forces with all the other

J. Bonini; F. Llorca; H. Bung; A. Juanicotena

268

Impact life prediction modeling of TFBGA packages under board level drop test  

Microsoft Academic Search

Reliability performance of IC packages during drop impact is critical, especially for handheld electronic products. Currently, there is no model that provides good correlation with experimental measurements of acceleration and impact life. In this paper, detailed drop tests and simulations are performed on TFBGA (thin-profile fine-pitch BGA) and VFBGA (very-thin-profile fine-pitch BGA) packages at board level using testing procedures developed

Tong Yan Tee; Hun Shen Ng; Chwee Teck Lim; Eric Pek; Zhaowei Zhong

2004-01-01

269

Impact of peer interaction on conceptual test performance  

NSDL National Science Digital Library

We analyze the effectiveness of working in pairs on the Conceptual Survey of Electricity and Magnetism test in a calculus-based introductory physics course. Students who collaborated with a peer showed significantly larger normalized gain on individual testing than those who did not collaborate. We did not find statistically significant differences between the performance of students who were given an opportunity to formulate their own response before the peer discussions, compared to those who were not. Peer collaboration also shows evidence for the co-construction of knowledge. Discussions with individual students show that students themselves value peer interaction. We discuss the effect of pairing students with different individual achievements.

Singh, Chandralekha

2012-07-10

270

16 CFR 1203.17 - Impact attenuation test.  

Code of Federal Regulations, 2010 CFR

...impactor onto an elastomeric test medium (MEP). The spherical impactor shall be a 146...0.1 kg (11.0±0.22 lb). The MEP shall be 152 mm (6 in.) in diameter and...have a durometer of 60±2 Shore A. The MEP shall be affixed to the top surface of...

2009-01-01

271

16 CFR 1203.17 - Impact attenuation test.  

Code of Federal Regulations, 2010 CFR

...impactor onto an elastomeric test medium (MEP). The spherical impactor shall be a 146...0.1 kg (11.0±0.22 lb). The MEP shall be 152 mm (6 in.) in diameter and...have a durometer of 60±2 Shore A. The MEP shall be affixed to the top surface of...

2010-01-01

272

Polynomial cointegration tests of anthropogenic impact on global warming  

NASA Astrophysics Data System (ADS)

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.

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

2012-07-01

273

Polynomial cointegration tests of anthropogenic impact on global warming  

NASA Astrophysics Data System (ADS)

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.

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

2012-11-01

274

Multisensor data fusion for impact-echo testing of concrete structures  

NASA Astrophysics Data System (ADS)

Based on the investigation of spatial variations of impact-echo signals for different source and receiver locations, a simple multisensor data fusion strategy is proposed to increase the accuracy of nondestructive evaluation of concrete structures using the impact-echo test. The data fusion strategy fuses the ratios between spectral amplitudes of the delamination and concrete bottom echo signals (D/B ratios) from multiple source-receiver arrays. The fused D/B ratios demonstrate different characteristics for test locations above the delamination, above the sound concrete, and across the delamination boundary. These characteristics can be used to accurately locate the delamination and its boundaries without increasing testing time. The applicability of the multisensor data fusion for impact-echo testing is validated using both numerical simulation and experimental testings.

Zhang, Ying; Wei, Xiangmin; Tsai, Yi-Te; Zhu, Jinying; Fetrat, Farhad A.; Gucunski, Nenad

2012-07-01

275

Impact testing of the H1224A shipping/storage container  

SciTech Connect

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.

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

1994-05-01

276

Impact Testing of Plug-In Circuit Packages for High Reliability  

Microsoft Academic Search

A mechanical impact test has been used to improve the production reliability of plugin circuit packages for a Bell System electronic switching system. Mechanically unstable components which could cause intermittent electrical failures in system operation are located by monitoring the electrical output of the package during the test.

R. C. Kohl; D. J. Wadsworth

1965-01-01

277

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

Microsoft Academic Search

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

Leonardo D'Acquisto; Roberto Montanini

2008-01-01

278

Ductile Fracture Simulation in the Taylor Rod Impact Test Using Continuum Damage Mechanics  

Microsoft Academic Search

Taylor rod impact tests are used as experimental and numerical tests for determining the mechanical behavior of materials subjected to high strain rates. At sufficiently high velocities, a significant plastic deformation leading to fracture is observed. In this article, fracture in Taylor rod made of AISI1045 steel is simulated using a continuum damage mechanics model. The simulation is performed in

Sachin S. Gautam; Raman Babu; P. M. Dixit

2011-01-01

279

Fracture initiation mechanisms of thin hard coatings during the impact test  

Microsoft Academic Search

The impact test can be successfully applied for the characterization of thin and thick coatings fatigue and creep properties, respectively. In the present paper experimental and analytical investigations concerning thin films fracture initiation during this test are introduced. The damage initiation of thin hard coatings deposited on smooth surfaces is mainly induced by fatigue mechanisms and characterized by the removal

K.-D Bouzakis; A Siganos

2004-01-01

280

Infrared analysis and Izod impact testing of multicomponent polymer composites: polyethylene\\/ EP D M \\/filler systems  

Microsoft Academic Search

Various multicomponent polyethylene\\/rubber\\/filler composites have been characterized by diffuse reflectance infrared spectroscopy (DRIFT) and notched lzod impact testing. This work is part of a study which also included solid state and melt state dynamic mechanical testing of the same composites. The fillers used were an oxidized silicon powder and calcium carbonate. Fillers were also treated with coupling agents gamma -ami

C. Scott; H. Ishlda; F. H. J. Maurer

1987-01-01

281

The Impact of Intensive Reading Interventions on Student Standardized Test Scores  

ERIC Educational Resources Information Center

|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…

Munoz, Carolyn Sue

2010-01-01

282

Summary of the Results of Crash Tests Performed on the Connecticut Impact Attenuation System (CIAS).  

National Technical Information Service (NTIS)

The report summarizes the results of nine full-scale crash tests performed on the Connecticut Impact Attenuation System (CIAS). Tests were performed in accordance with the requirements of TRB Circular 191 and NCHRP Report 230. Design changes based on the ...

J. F. Carney C. E. Dougan

1983-01-01

283

The TOEFL Trump Card: An Investigation of Test Impact in an ESL Classroom  

ERIC Educational Resources Information Center

Much of the research on the effects of tests on foreign and second-language classrooms has examined the impact or washback effect that commercial/institutional language tests, such as the TOEFL, have on teachers' instructional practices (Hughes, 1998; Wall & Alderson, 1993). Using a case study methodology, this study uncovered the ways in which…

Johnson, Karen E.; Jordan, Stefanie Rehn; Poehner, Matthew E.

2005-01-01

284

The TOEFL Trump Card: An Investigation of Test Impact in an ESL Classroom  

ERIC Educational Resources Information Center

|Much of the research on the effects of tests on foreign and second-language classrooms has examined the impact or washback effect that commercial/institutional language tests, such as the TOEFL, have on teachers' instructional practices (Hughes, 1998; Wall & Alderson, 1993). Using a case study methodology, this study uncovered the ways in which…

Johnson, Karen E.; Jordan, Stefanie Rehn; Poehner, Matthew E.

2005-01-01

285

A literature review of the psychological impact of genetic testing on breast cancer patients  

Microsoft Academic Search

ObjectiveEasier access and increased awareness results in more referral for genetic testing for hereditary breast cancer in healthy at-risk women and breast cancer patients. To investigate the psychological impact of genetic testing on breast cancer patients, literature pertaining to this group was reviewed.

Kathryn J. Schlich-Bakker; Herman F. J. ten Kroode; Margreet G. E. M. Ausems

2006-01-01

286

Impact of proper site characterization and ground truthing on test results for UXO detection  

Microsoft Academic Search

This paper describes the impact of proper site characterization and ground truthing on test results for the detection of Unexploded Ordnance (UXO). Techniques employed to do proper site characterization and methods used to generate accurate and meaningful ground truth data are presented within the context of recent data collections held at the Joint UXO Coordination Office's (JUXOCO) test site at

John D. Hodapp; James Campbell

1999-01-01

287

Inverse method for the analysis of instrumented impact tests of polymers  

Microsoft Academic Search

Impact testing has become an important technique to determine the parameters associated with dynamic fracture of polymeric materials. These parameters are commonly calculated from the experimentally measured load versus time curves. However, these curves are not what theoretically should be used for this purpose, because the measured load is not equal to the load exerted on the tested specimen, load

Valeria Pettarin; Patricia Frontini; Guillermo Eliçabe

2003-01-01

288

Impact of testing styles and testing methods on achievement in general chemistry  

NASA Astrophysics Data System (ADS)

This research conducted at a community college located in Northeast Texas studied testing style and testing methods in relation to achievement in general chemistry. Data was collected and examined from 212 participants. Of these, 143 completed both the MBTI and PEPS surveys. This provided 71 subjects designated as Sensor (S) types for the final phase of the study. The subjects were divided into two groups by performance on the PEPS. One group consisted of subjects that indicated a preference to communicate (test) using a formal/pencil-paper test format (linguistic testing style) and the other subjects indicated a preference to communicate (test) using a hands-on/movement test format (tactile testing style). All subjects were administered both a linguistic and tactile pretest prior to treatment and both a linguistic and tactile posttest after treatment. The data was analyzed using a 2 x 2 ANOVA for significant effects at the p < 0.05 level of confidence. The results indicated a significant interaction effect between the student testing style and test methods. While not conclusive, this study does indicate that the type of testing done in general chemistry may be favoring students with certain types of communication preferences (testing styles). Therefore students with many of the worker characteristics desired by the chemical industry may not be successful in general chemistry and choose a different career path.

Howell, Byron Edward

2001-12-01

289

Methods for testing theory and evaluating impact in randomized field trials  

PubMed Central

Randomized field trials provide unique opportunities to examine the effectiveness of an intervention in real world settings and to test and extend both theory of etiology and theory of intervention. These trials are designed not only to test for overall intervention impact but also to examine how impact varies as a function of individual level characteristics, context, and across time. Examination of such variation in impact requires analytical methods that take into account the trial’s multiple nested structure and the evolving changes in outcomes over time. The models that we describe here merge multilevel modeling with growth modeling, allowing for variation in impact to be represented through discrete mixtures—growth mixture models—and nonparametric smooth functions—generalized additive mixed models. These methods are part of an emerging class of multilevel growth mixture models, and we illustrate these with models that examine overall impact and variation in impact. In this paper, we define intent-to-treat analyses in group-randomized multilevel field trials and discuss appropriate ways to identify, examine, and test for variation in impact without inflating the Type I error rate. We describe how to make causal inferences more robust to misspecification of covariates in such analyses and how to summarize and present these interactive intervention effects clearly. Practical strategies for reducing model complexity, checking model fit, and handling missing data are discussed using six randomized field trials to show how these methods may be used across trials randomized at different levels.

Brown, C. Hendricks; Wang, Wei; Kellam, Sheppard G.; Muthen, Bengt O.; Petras, Hanno; Toyinbo, Peter; Poduska, Jeanne; Ialongo, Nicholas; Wyman, Peter A.; Chamberlain, Patricia; Sloboda, Zili; MacKinnon, David P.; Windham, Amy

2008-01-01

290

Evaluation of seismic spatial interaction effects through an impact testing program  

SciTech Connect

The consequences of non-seismically qualified objects falling and striking essential, seismically qualified objects is an analytically difficult problem to assess. Analytical solutions to impact problems are conservative and only available for simple situations. In a nuclear facility, the numerous ``sources`` and ``targets`` requiring evaluation often have complex geometric configurations, which makes calculations and computer modeling difficult. Few industry or regulatory rules are available for this specialized assessment. A drop test program was recently conducted to ``calibrate`` the judgment of seismic qualification engineers who perform interaction evaluations and to further develop seismic interaction criteria. Impact tests on varying combinations of sources and targets were performed by dropping the sources from various heights onto targets that were connected to instruments. This paper summarizes the scope, test configurations, and some results of the drop test program. Force and acceleration time history data and general observations are presented on the ruggedness of various targets when subjected to impacts from different types of sources.

Thomas, B.D.; Driesen, G.E.

1993-04-01

291

Evaluation of seismic spatial interaction effects through an impact testing program  

SciTech Connect

The consequences of non-seismically qualified objects falling and striking essential, seismically qualified objects is an analytically difficult problem to assess. Analytical solutions to impact problems are conservative and only available for simple situations. In a nuclear facility, the numerous sources'' and targets'' requiring evaluation often have complex geometric configurations, which makes calculations and computer modeling difficult. Few industry or regulatory rules are available for this specialized assessment. A drop test program was recently conducted to calibrate'' the judgment of seismic qualification engineers who perform interaction evaluations and to further develop seismic interaction criteria. Impact tests on varying combinations of sources and targets were performed by dropping the sources from various heights onto targets that were connected to instruments. This paper summarizes the scope, test configurations, and some results of the drop test program. Force and acceleration time history data and general observations are presented on the ruggedness of various targets when subjected to impacts from different types of sources.

Thomas, B.D.; Driesen, G.E.

1993-01-01

292

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

NASA Astrophysics Data System (ADS)

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.

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

2001-06-01

293

Impact testing of duplex and non-duplex (Ti,Al)N and Cr–N PVD coatings  

Microsoft Academic Search

An impact test has been used to evaluate the impact resistance of duplex (i.e. pre-nitrided) and non-duplex PVD (Ti,Al)N and Cr–N coatings. The impact tests were carried out using a cyclic loading system developed at the University of Hull. Two different balls (tungsten carbide and hardened SAE 52100 steel) were used as impact bodies. After the test, samples were observed

J. C. A Batista; C Godoy; A Matthews

2003-01-01

294

Nano-impact test on a TiAlN PVD coating and correlation between experimental and FEM results  

Microsoft Academic Search

Nano-impact test on PVD coatings is an efficient method for investigating film failure mechanisms. During this test, the coating is subjected to repetitive impacts by a diamond indenter, inducing high local deformations and stresses into the film material, which may lead to coating failure.In the paper, coated specimens with a TiAlN PVD film were investigated by nano-impact tests. The nano-impacts

K.-D. Bouzakis; S. Gerardis; G. Skordaris; E. Bouzakis

295

Noise studies for environmental impact assessment of an outdoor engine test facility  

NASA Astrophysics Data System (ADS)

The potential impact of noise in the community surrounding a proposed outdoor test facility in the Ottawa area was evaluated. The test stand was planned for the testing of high performance gas turbine engines. Theoretical predictions based on the outdoor sound propagation model were made for the noise generated from a General Electric F404 engine. The results were verified by carrying measurements of noise generated from a single engine of a parked CF-18 aircraft. The measured results qualitatively confirmed the validity of theoretical predictions. However, the tests clearly demonstrated the strong influence of the atmospheric conditions in the observed noise levels in the surrounding community. The usefulness of the theoretical predictions in devising noise control measures in the test area and for the scheduling of tests in favorable weather conditions to minimize noise impact in the surrounding area were discussed.

Krishnappa, G.

1992-04-01

296

"Sandbagging" baseline test performance on ImPACT, without detection, is more difficult than it appears.  

PubMed

Participants coached to display poor effort on neuropsychological tests have successfully evaded detection. Recent research has documented that 89% college athletes instructed to perform poorly on a follow-up baseline ImPACT (Immediate Post-concussion Assessment and Cognitive Testing) test were unable to bypass detection, but otherwise, sandbagging on baseline testing has not been directly studied. In an analog study intended to measure participants' ability to successfully sandbag, we compared baseline test performance in three groups of individuals, instructed: (a) to perform their best, (b) to malinger without guidance (e.g., naïve), and (c) how to malinger (e.g., coached), using ImPACT, the Medical Symptom Validity Test (MSVT), and the Balance Error Scoring System. The MSVT identified more participants in the naïve (80%) and coached (90%) groups than those automatically "flagged" by ImPACT (60% and 75%, respectively). Inclusion of additional indicators within ImPACT increased identification to 95% of naïve and 100% of coached malingerers. These results suggest that intentional "sandbagging" on baseline neurocognitive testing can be readily detected. PMID:23403552

Schatz, Philip; Glatts, Colette

2013-02-11

297

Characterization of fatigue and adhesion properties of aC:H\\/CrN coatings on bearing rings by impact tests  

Microsoft Academic Search

The impact test is used for the quantitative assessment of various properties of thin hard coatings, deposited on machine elements, tools etc. This test is mainly applied on coated specimens with simple geometries such as of cutting inserts and coated plates. In the described investigations, perpendicular and inclined impact tests were conducted directly on PVD coated bearing rings. The tests

K.-D. Bouzakis; A. Asimakopoulos; M. Batsiolas

2008-01-01

298

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

Microsoft Academic Search

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%

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

2011-01-01

299

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

Microsoft Academic Search

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

Philip Schatz

2010-01-01

300

Scaling numerical models for hypervelocity test sled slipper-rail impacts  

Microsoft Academic Search

Hypervelocity test sled slipper-rail impacts have been simulated numerically using the finite volume hydrocode, ChartD to the Three-Halves (CTH). This study addresses the difficulties of applying CTH model solutions to real test sled runs. Past CTH models using dimensions different than actual test sleds have been used to study phenomenological aspects of the problem. However, quantitative results from the CTH

A. G. Szmerekovsky; A. N. Palazotto; W. P. Baker

2006-01-01

301

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

NASA Astrophysics Data System (ADS)

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.

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

1999-06-01

302

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

Microsoft Academic Search

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

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

1982-01-01

303

Comparison of joint level impact fatigue resistance and board level drop test  

Microsoft Academic Search

The purpose of the present study is to investigate the behavior of solder joints under high strain rate repeated loading during micro-impact testing. SAC 105 and SAC 305 solder alloys on electrolytic nickel-gold and copper-OSP pads were used in this study. In doing so, the dependency on factors such as impact energy and solder alloy was studied.In terms of solder

Pradosh Guruprasad; James Pitarresi

2009-01-01

304

Deformation behavior of Inconel 690 super alloy evaluated by impact test  

Microsoft Academic Search

The dynamic impact deformation behavior, fracture characteristics and microstructural evolution of Inconel 690 alloy under high rate loading conditions are studied. Mechanical impact tests are performed at strain rates ranging from 2.3×103 to 8.3×103s?1 at room temperature by compressive split-Hopkinson bar. The effects of strain rate on dynamic flow response, work hardening characteristics, strain rate sensitivity and thermal activation volume

Woei-Shyan Lee; Chen-Yang Liu; Tai-Nong Sun

2004-01-01

305

Ceramic nuclear fuel mechanical resistance development by means of dynamic impact testing.  

PubMed

In commercial reactors where a 'pellet missing surface' is observed a cladding crack has also been observed several times. Chips are produced mainly by dynamic impacts during pellet production process as a whole, i.e. emptying the sintering boats, pellets handling, vibration in the bowl feeder and grinding. At this work UO(2) chipping behavior was investigated and showed that pellets with higher density resist more to impacts and also that at the lowest impact angle tested the pellet weight loss was quite high. PMID:21190863

Santana, H H S; Maier, G; Ródenas, J

2010-12-17

306

Social and psychological impact of HPV testing in cervical screening: a qualitative study  

PubMed Central

Objective Human papillomavirus (HPV) testing has been proposed for inclusion in the UK cervical screening programme. While testing may bring some benefits to the screening programme, testing positive for HPV, a sexually transmitted virus, may have adverse social and psychological consequences for women. The aim of this study was to examine the social and psychological impact of HPV testing in the context of cervical cancer screening. Method In?depth interviews generating qualitative data were carried out with 74 women participating in HPV testing in England between June 2001 and December 2003. Purposive sampling was used to ensure heterogeneity in age, ethnic group, marital status, socioeconomic background, cytology, and HPV results among participants. Results Testing positive for HPV was associated with adverse social and psychological consequences, relating primarily to the sexually transmitted nature of the virus and its link to cervical cancer. Women described feeling stigmatised, anxious and stressed, concerned about their sexual relationships, and were worried about disclosing their result to others. Anxiety about the infection was widespread, but the impact of testing positive varied. The psychological burden of the infection related to women's relationship status and history, their social and cultural norms and practices around sex and relationships, and their understanding of key features of HPV. Conclusion HPV testing should be accompanied by extensive health education to inform women and to de?stigmatise infection with the virus to ensure that any adverse impact of the infection on women's wellbeing is minimised.

McCaffery, K; Waller, J; Nazroo, J; Wardle, J

2006-01-01

307

A unified theory of impact crises and mass extinctions: quantitative tests.  

PubMed

Several quantitative tests of a general hypothesis linking impacts of large asteroids and comets with mass extinctions of life are possible based on astronomical data, impact dynamics, and geological information. The waiting times of large-body impacts on the Earth derived from the flux of Earth-crossing asteroids and comets, and the estimated size of impacts capable of causing, large-scale environmental disasters, predict the impacts of objects > or = 5 km in diameter (> or = 10(7) Mt TNT equivalent) could be sufficient to explain the record of approximately 25 extinction pulses in the last 540 Myr, with the 5 recorded major mass extinctions related to impacts of the largest objects of > or = 10 km in diameter (> or = 10(8) Mt events). Smaller impacts (approximately 10(6) Mt), with significant regional environmental effects, could be responsible for the lesser boundaries in the geologic record. Tests of the "kill curve" relationship for impact-induced extinctions based on new data on extinction intensities, and several well-dated large impact craters, also suggest that major mass extinctions require large impacts, and that a step in the kill curve may exist at impacts that produce craters of approximately 100 km diameter, smaller impacts being capable of only relatively weak extinction pulses. Single impact craters less than approximately 60 km in diameter should not be associated with detectable global extinction pulses (although they may explain stage and zone boundaries marked by lesser faunal turnover), but multiple impacts in that size range may produce significant stepped extinction pulses. Statistical tests of the last occurrences of species at mass-extinction boundaries are generally consistent with predictions for abrupt or stepped extinctions, and several boundaries are known to show "catastrophic" signatures of environmental disasters and biomass crash, impoverished postextinction fauna and flora dominated by stress-tolerant and opportunistic species, and gradual ecological recovery and radiation of new taxa. Isotopic and other geochemical signatures are also generally consistent with the expected after-effects of catastrophic impacts. Seven of the recognized extinction pulses seem to be associated with concurrent (in some cases multiple) stratigraphic impact markers (e.g., layers with high iridium, shocked minerals, microtektites), and/or large, dated impact craters. Other less well-studied crisis intervals show elevated iridium, but well below that of the K/T spike, which might be explained by low-Ir impactors, ejecta blowoff, or sedimentary reworking and dilution of impact signatures. The best explanation for a possible periodic component of approximately 30 Myr in mass extinctions and clusters of impacts is the pulselike modulation of the comet flux associated with the solar system's periodic passage through the plane of the Milky Way Galaxy. The quantitative agreement between paleontologic and astronomical data suggests an important underlying unification of the processes involved. PMID:11543121

Rampino, M R; Haggerty, B M; Pagano, T C

1997-05-30

308

Accelerated 54{degree}C irradiated test of Shippingport neutron shield tank and HFIR vessel materials  

SciTech Connect

Charpy V-notch specimens (ASTM Type A) and 5.74-mm diameter tension test specimens of the Shippingport Reactor Neutron Shield Tank (NST) (outer wall material) were irradiated together with Charpy V-notch specimens of the Oak Ridge National Laboratory (ORNI), High,, Flux Isotope Reactor (HFIR) vessel (shell material), to 5.07 {times} 10{sup 17} n/cm{sup 2}, E > 1 MeV. The irradiation was performed in the Ford Nuclear Reactor (FNR), a test reactor, at a controlled temperature of 54{degrees}C (130{degrees}F) selected to approximate the prior service temperatures of the cited reactor structures. Radiation-induced elevations in the Charpy 41-J transition temperature and the ambient temperature yield strength were small and independent of specimen test orientation (ASTM LT vs. TL). The observations are consistent with prior findings for the two materials (A 212-B plate) and other like materials irradiated at low temperature (< 200{degrees}C) to low fluence. The high radiation embrittlement sensitivity observed in HFIR vessel surveillance program tests was not found in the present accelerated irradiation test. Response to 288{degrees}C-168 h postirradiation annealing was explored for the NST material. Notch ductility recovery was found independent of specimen test orientation but dependent on the temperature within the transition region at which the specimens were tested.

Hawthorne, J.R. [Materials Engineering Associates, Inc., Lanham, MD (United States); Rosinski, S.T. [Sandia National Labs., Albuquerque, NM (United States)

1993-01-01

309

Accelerated 54[degree]C irradiated test of Shippingport neutron shield tank and HFIR vessel materials  

SciTech Connect

Charpy V-notch specimens (ASTM Type A) and 5.74-mm diameter tension test specimens of the Shippingport Reactor Neutron Shield Tank (NST) (outer wall material) were irradiated together with Charpy V-notch specimens of the Oak Ridge National Laboratory (ORNI), High,, Flux Isotope Reactor (HFIR) vessel (shell material), to 5.07 [times] 10[sup 17] n/cm[sup 2], E > 1 MeV. The irradiation was performed in the Ford Nuclear Reactor (FNR), a test reactor, at a controlled temperature of 54[degrees]C (130[degrees]F) selected to approximate the prior service temperatures of the cited reactor structures. Radiation-induced elevations in the Charpy 41-J transition temperature and the ambient temperature yield strength were small and independent of specimen test orientation (ASTM LT vs. TL). The observations are consistent with prior findings for the two materials (A 212-B plate) and other like materials irradiated at low temperature (< 200[degrees]C) to low fluence. The high radiation embrittlement sensitivity observed in HFIR vessel surveillance program tests was not found in the present accelerated irradiation test. Response to 288[degrees]C-168 h postirradiation annealing was explored for the NST material. Notch ductility recovery was found independent of specimen test orientation but dependent on the temperature within the transition region at which the specimens were tested.

Hawthorne, J.R. (Materials Engineering Associates, Inc., Lanham, MD (United States)); Rosinski, S.T. (Sandia National Labs., Albuquerque, NM (United States))

1993-01-01

310

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

Microsoft Academic Search

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

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

2010-01-01

311

Evaluating the Impact of Test Accommodations on Test Scores of LEP Students & Non-LEP Students.  

ERIC Educational Resources Information Center

|Using a quasi-experimental analysis of variance (ANOVA) design, this project examined the effects of the use of accommodations with students of limited English proficiency (LEP) and non-LEP students and whether the use of accommodations affected the validity of test score interpretations. Major accommodations examined were extra time, and extra…

Hafner, Anne L.

312

HIV Testing in Correctional Agencies and Community Treatment Programs: The Impact of Internal Organizational Structure  

PubMed Central

This study compares the provision of HIV testing in a nationally representative sample of correctional agencies and community-based substance abuse treatment programs and identifies the internal organizational-level correlates of HIV testing in both organizations. Data are derived from the CJ-DATS’ National Criminal Justice Treatment Practices Survey (NCJTP). Using an organizational diffusion theoretical framework (Rogers, 2003), the impact of Centralization of Power, Complexity, Formalization, Interconnectedness, Organizational Resources, and Organizational Size on HIV testing was examined in correctional agencies and treatment programs. While there were no significant differences in the provision of HIV testing among correctional agencies (49%) and treatment programs (50%), the internal organizational-level correlates were more predictive of HIV testing in correctional agencies. Specifically, all dimensions, with the exception of Formalization, were related to the provision of HIV testing in correctional agencies. Implications for correctional agencies and community treatment to adopt HIV testing are discussed.

Oser, Carrie B.; Tindall, Michele Staton; Leukefeld, Carl G.

2007-01-01

313

Use of parabolic reflector to amplify in-air signals generated during impact-echo testing.  

PubMed

The impact-echo method is a commonly used nondestructive testing technique for elastic plates in civil engineering. The impact-echo mode corresponds to the frequency at zero group velocity of S(1) Lamb mode. Recent development of the air-coupled impact-echo (ACIE) method introduces the possibility for rapid scanning of large structures and increases the practicality of in situ measurements. However, sensors used in ACIE are susceptible to ambient noise, which complicates in situ ACIE measurements. This letter presents the results of ACIE measurements taken using a parabolic reflector together with standard measurement microphones to increase the signal to noise ratio for ACIE measurements. The signal gain and effects of sensor location with respect to impact location are discussed. PMID:21974487

Dai, Xiaowei; Zhu, Jinying; Tsai, Yi-Te; Haberman, Michael R

2011-10-01

314

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

NASA Astrophysics Data System (ADS)

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.

Morton, John; Ho, Henjen

1992-06-01

315

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

Microsoft Academic Search

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

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

2006-01-01

316

Development of a 3-component Load Cell for Structural Impact Testing  

Microsoft Academic Search

This paper describes the development of a 3-component load cell for structural impact testing. The test specimen is mounted\\u000a directly on the load cell, which measures the axial force as well as two orthogonal bending moments. Basically, the load cell\\u000a is a stocky cylinder with thick end flanges machined in one piece of high-strength steel. The load measurement system is

A. G. Hanssen; T. Auestad; M. Langseth; T. Tryland

2005-01-01

317

LX04 Violence Measurements-Steven Tests Impacted by Projectiles Shot from a Howitzer Gun  

Microsoft Academic Search

Characterization of the reaction violence of LX-04 explosive (85% HMX and 15% Viton A 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 170–300 m\\/s to react (ignite) the LX-04 explosive. Blast overpressure gauges,

Steven K. Chidester; Kevin S. Vandersall; Lori L. Switzer; Craig M. Tarver

2006-01-01

318

LX04 Violence Measurments: Steven Tests Impacted By Projectiles Shot From A Howitzer Gun  

Microsoft Academic Search

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

Steven K. Chidester

2005-01-01

319

LX04 Violence Measurements-Steven Tests Impacted by Projectiles Shot from a Howitzer Gun  

Microsoft Academic Search

Characterization of the reaction violence of LX-04 explosive (85% HMX and 15% Viton A 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 170-300 m\\/s to react (ignite) the LX-04 explosive. Blast overpressure gauges,

Steven K. Chidester; Kevin S. Vandersall; Lori L. Switzer; Craig M. Tarver

2006-01-01

320

Analysis of colliding vehicle interactions for the passenger rail train-to-train impact test  

Microsoft Academic Search

A full-scale train-to-train impact test was performed in which a cab car-led passenger train traveling at 30 mph collided with a standing locomotive-led train. During the test, the lead cab car overrode the cab of the standing locomotive, sustaining approximately 20 feet of crush, while the cab of the locomotive remained essentially intact. In this study, a finite element-based analysis

Richard Stringfellow; Robert Rancatore; Patricia Llana; Ronald Mayville

2004-01-01

321

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

Microsoft Academic Search

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

Giovanni Belingardi; Roberto Vadori

2002-01-01

322

What's the Point? How Point-of-Care STI Tests Can Impact Infected Patients  

PubMed Central

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).

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

2010-01-01

323

Analytical and Sampling Methodology Used for Determinig the Impact of a Mhd Test Facility  

Microsoft Academic Search

The suitability of various analytical and sampling methodologies for the determination of the environmental impact of a test scale MHD power generation facility is evaluated. Media which were sampled included airbourne particulates, soils, vegetation and natural waters. Analytical techniques examined include plasma emission and atomic absorption spectrometry and ion chromatography. Except in the case of the sampling of particulates with

Dennis R. Jenke

1984-01-01

324

A NEW APPROACH TO IMPACT TESTING INSTRUMENTATION USING AN ELECTRONIC SLAVE HAMMER  

Microsoft Academic Search

An electronic slave hammer is used to improve the performance of impact testing. The electronic programmer as well as the power electronic circuits are presented. The geometry of the piston tip of the hammer and on duration of contact between the tip and the structure is discussed. It is shown that the polyreference method of modal analysis is applicable to

I. Tawfiq; T. Vinh; T. Chouychai

1997-01-01

325

Development of apparatus for magnetic measurements of Charpy impact test pieces  

Microsoft Academic Search

Since magnetic properties of ferromagnetic steels have a good correlation with their mechanical properties, those mechanical properties will be evaluated by magnetic measurements. An apparatus for measurement of BH curves of Charpy impact test pieces was therefore developed in order to evaluate the integrity of nuclear reactor pressure vessels nondestructively. In this paper, the operation of developed apparatus is demonstrated

Hiroaki Kikuchi; Mamoru Harada; Katsuyuki Ara; Yasuhiro Kamada; Satoru Kobayashi; Seiki Takahashi

2007-01-01

326

The mechanism of brittle fracture in notched impact tests on polycarbonate  

Microsoft Academic Search

The impact testing of notched polycarbonate bars that are thick enough to yield in plane strain has been investigated. Shear bands occur in the plastic zone that resemble the slip line field for yielding from a circular notch. Eventually, an internal craze nucleates at the tip of the plastic zone, where the stresses are highest, and a crack forms in

N. J. Mills

1976-01-01

327

PATTERNS OF WHEELCHAIR RESPONSE AND SEATING-SYSTEM FAILURES IN FRONTAL-IMPACT SLED TESTS  

Microsoft Academic Search

Data from 259 frontal impact sled tests of commercial wheelchairs and seating systems were compiled and retrospectively analyzed. These data have general application to the development of additional design and performance requirements for transit wheelchair (WC) standards, and are specifically needed to guide the design and performance specifications of a reusable surrogate wheelchair base (SWCB) that can be used for

Miriam A. Manary; Laura M. Woodruff; Gina E. Bertocci; Lawrence W. Schneider

328

A Study of Minimum Competency Tests and Their Impact. Final Report.  

ERIC Educational Resources Information Center

|This project studied the impact of Minimum Competency Tests (MCT) on the educational careers of secondary students. The educational experiences of those students passing the MCT were compared with the experiences of those students not passing the MCT. The study compared three categories of students (learning handicapped, educationally marginal,…

MacMillan, Donald L.; And Others

329

Finite element analysis of Sn-Ag-Cu solder joint failure under impact test  

Microsoft Academic Search

BGAs packaging offer high pin counts and lower interconnecting space, and are suitable for high density packaging. However, it is difficult to inspect individual solder joints on BGA assembly by conventional visual methods and need a complicated practice on rework. Ball impact test is a useful method to estimate the reliability of BGA solder joint. In this study, the three-dimensional

Ganran Tang; Bing An; Yiping Wu; Fengshun Wu

2009-01-01

330

Thoracic response to high-rate blunt impacts using an advanced testing platform.  

PubMed

ehind Armor Blunt Trauma (BABT) is a persistent concern for both the military and civil law enforcement. Although personal protective equipment (PPE), including soft and hard body armor, mitigates penetrating injuries from ballistic threats, the impact generates a backface deformation which creates a high-rate blunt impact to the body and potential internal injury (i.e., BABT). A critical need exists to understand the mechanics of the human response and subsequently evaluate the efficacy of current and proposed PPE in mitigating BABT injury risk. Current human surrogate test platforms lack anatomical fidelity or instrumentation for capturing the dynamic transfer of energy during the event. Therefore, we have developed and tested a Human Surrogate Torso Model (HSTM) composed of biosimulants representing soft tissues and skeleton of the human torso. A matrix of pressure transducers were embedded in the soft tissue and a custom displacement sensor was mounted to the skeletal structure to measure sternum displacement. A series of non-penetrating, high energy ballistic tests were performed with the HSTM. Results indicate that both sternum displacement and internal localized pressure are sensitive to impact energy and location. These data provide a spatial and temporal comparison to the current standard (static clay measurements) and a method for evaluating the applicability of thoracic injury metrics, including the Viscous Criterion, for BABT. The HSTM provides an advanced, biomechanically relevant test platform for determining the thoracic response to dynamic loading events due to non-penetrating ballistic impacts. PMID:22846323

Wickwire, Alexis C; Merkle, Andrew C; Carneal, Catherine M; Pauson, Jeffrey M

2012-01-01

331

The inappropriateness of helmet drop tests in assessing neck protection in head-first impacts  

Microsoft Academic Search

Protecting the cervical spine in situations of axial com pressive loading is indeed complex. Results from a number of crash simulations suggest that the mecha nisms of head impact causing brain damage and those causing neck injury are different. The idea that neck injuries can be predicted from results of helmet drop tests or that the helmet is capable of

P. J. Bishop; R. P. Wells

1990-01-01

332

An Experiment on Lead-Time Impact in Testing of Distributed Real-Time Systems  

Microsoft Academic Search

In the search for an efficient test method for distributed real-time systems, an experiment is conducted that investigates the impact on the lead time required to identify a defect, depending on what information is available. One group of experiment participants were given a system monitoring trace, while a control group were given node monitoring traces. The information made available in

Thomas Olssonl; Per Runeson; Niclas Bauer; Lars Bratthall

2001-01-01

333

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

Microsoft Academic Search

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

David Kaplan

1988-01-01

334

Impact of Experimental Factors in Soil Phosphorus Tests: Shaking Vessel, Filtration, and Centrifugation  

Microsoft Academic Search

In the analysis of Mehlich III, deionized water (DI), Bray, and Olsen soil phosphorus (P) extractions, variations in shaking vessel, centrifugation, and filter paper result in different soil test P (STP) values. Of these factors, centrifugation and type of filtration were found to have the greatest impact on the results of water?extractable P (WEP), that is, extraction with DI. Further

Daniel D. Ebeling; Joel G. Davis

2009-01-01

335

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

ERIC Educational Resources Information Center

|The impact of misspecification on the estimation, testing, and improvement of structural equation models was assessed via a population study in which a prototypical latent variable model was misspecified. Results provide insights into the maximum likelihood estimator versus a limited two-stage least squares estimator in LISREL. (TJH)|

Kaplan, David

1988-01-01

336

Simulated Tests of Differential Item Functioning Using SIBTEST with and without Impact  

ERIC Educational Resources Information Center

Monte Carlo simulations with 20,000 replications are reported to estimate the probability of rejecting the null hypothesis regarding DIF using SIBTEST when there is DIF present and/or when impact is present due to differences on the primary dimension to be measured. Sample sizes are varied from 250 to 2000 and test lengths from 10 to 40 items.…

Klockars, Alan J.; Lee, Yoonsun

2008-01-01

337

Head impact mechanisms of a child occupant seated in a child restraint system as determined by impact testing.  

PubMed

In side collision accidents, the head is the most frequently injured body region for child occupants seated in a child restraint system (CRS). Accident analyses show that a child's head can move out of the CRS shell, make hard contact with the vehicle interior, and thus sustain serious injuries. In order to improve child head protection in side collisions, it is necessary to understand the injury mechanism of a child in the CRS whose head makes contact with the vehicle interior. In this research, an SUV-to-car oblique side crash test was conducted to reconstruct such head contacts. A Q3s child dummy was seated in a CRS in the rear seat of the target car. The Q3s child dummy's head moved out beyond the CRS side wing, moved laterally, and made contact with the side window glass and the doorsill. It was demonstrated that the hard head contact, which produced a high HIC value, could occur in side collisions. A series of sled tests was carried out to reproduce the dummy kinematic behavior observed in the SUV-to-car crash test, and the sled test conditions such as sled angle, ECE seat slant angle and velocity-time history that duplicated the kinematic behavior were determined. A parametric study also was conducted with the sled tests; and it was found that the impact angle, harness slack, chest clip, and the CRS side wing shape affected the torso motion and head contact with the vehicle interior. PMID:22869307

Yoshida, Ryoichi; Okada, Hiroshi; Nomura, Mitsunori; Mizuno, Koji; Tanaka, Yoshinori; Hosokawa, Naruyuki

2011-11-01

338

The impact of response to the results of diagnostic tests for malaria: cost-benefit analysis  

PubMed Central

Objective Rapid diagnostic tests for malaria seem cost effective in standard analyses, but these do not take account of clinicians’ response to test results. This study tested the impact of clinicians’ response to rapid diagnostic test or microscopy results on the costs and benefits of testing at different levels of malaria transmission and in different age groups. Design Cost-benefit analysis using a decision tree model and clinical data on the effectiveness of diagnostic tests for malaria, their costs, and clinicians’ response to test results. Setting Tanzania. Methods Data were obtained from a clinical trial of 2425 patients carried out in three settings of varying transmission. Results At moderate and low levels of malaria transmission, rapid diagnostic tests were more cost beneficial than microscopy, and both more so than presumptive treatment, but only where response was consistent with test results. At the levels of prescription of antimalarial drugs to patients with negative tests that have been found in observational studies and trials, neither test methodis likely to be cost beneficial, incurring costs 10-250% higher, depending on transmission rate, than would have been the case with fully consistent responses to all test results. Microscopy becomes more cost beneficial than rapid diagnostic tests when its sensitivity under operational conditions approaches that of rapid diagnostic tests. Conclusions Improving diagnostic methods, including rapid diagnostic tests, can reduce costs and enhance the benefits of effective antimalarial drugs, but only if the consistency of response to test results is also improved. Investing in methods to improve rational response to tests is essential. Economic evaluations of diagnostic tests should take into account whether clinicians’ response is consistent with test results.

2008-01-01

339

Recent progress in subsized charpy specimen testing for fusion reactor materials development  

SciTech Connect

The current approach to developing structural materials for fusion reactors requires a heavy reliance on the use of small irradiation specimens largely because of limitations in available irradiation volumes. The miniature Charpy-V-notch specimen (MCVN) is one of several techniques currently under development. It has particular potential application in addressing problems associated with fracture mode transition in ferritic/martensitic steels. The authors have previously reported a technique for testing MCVNs that are one-third the size in all dimensions of a standard Charpy-V-notch (CVN) specimen. This involves an instrumented drop tower and a computerized data acquisition/processing system. We have now tested a variety of ferritic steels using MCVN specimens and compared the data to CVN data obtained by ourselves or others. These materials include A302B correlation monitor material, A508 forgings, Ht-9, a high-copper A533B weld, and an A710 copper-bearing steel heat-treated to four conditions. These heat treatments result in age hardening by copper precipitation and correspond to underaged, peak-hardened, and overaged conditions. The MCVN test appears to provide data that are both qualitatively and quantitatively similar to CVN data. The most promising approach to applying MCVN tests, in our opinion, is to extract fundamental property data. Even so, there are a number of differences between MCVN and CVN tests that remain to be sorted out.

Lucas, G.E.; Odette, G.R.; Sheckherd, J.W.; Krishnadev, M.R.

1986-01-01

340

Impact Testing of Stainless Steel Material at Room and Elevated Temperatures  

SciTech Connect

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.

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

2007-07-01

341

High-speed impact test of an air-transportable plutonium nitrate shipping container  

SciTech Connect

To obtain information on package response for comparison with other test environments, a high-speed impact test was performed on a modified Federal Republic of Germany 18B plutonium nitrate air-transportable container. The container, modified with reinforcing rings for improved crush resistance around the inner tube assembly, was impacted at a velocity of 137 m/s onto an unyielding surface. Substantial crushing of the foam overpack and extensive deformation of the container cavity occurred, causing release of the liquid surrogate contents from the titanium shipping container. The container damage resulting from the high-speed pulldown test was more severe than that from a 185-m free fall onto a semirigid surface by a similar container or the crush environment produced by a 9-m drop of a 2-Mg block onto the container resting on an unyielding surface.

Yoshimura, H.R.; Pope, R.B.; Leisher, W.B.; Joseph, B.J.

1980-04-01

342

Assessing transportation infrastructure impacts on rangelands: test of a standard rangeland assessment protocol  

USGS Publications Warehouse

Linear disturbances associated with on- and off-road vehicle use on rangelands has increased dramatically throughout the world in recent decades. This increase is due to a variety of factors including increased availability of all-terrain vehicles, infrastructure development (oil, gas, renewable energy, and ex-urban), and recreational activities. In addition to the direct impacts of road development, the presence and use of roads may alter resilience of adjoining areas through indirect effects such as altered site hydrologic and eolian processes, invasive seed dispersal, and sediment transport. There are few standardized methods for assessing impacts of transportation-related land-use activities on soils and vegetation in arid and semi-arid rangelands. Interpreting Indicators of Rangeland Health (IIRH) is an internationally accepted qualitative assessment that is applied widely to rangelands. We tested the sensitivity of IIRH to impacts of roads, trails, and pipelines on adjacent lands by surveying plots at three distances from these linear disturbances. We performed tests at 16 randomly selected sites in each of three ecosystems (Northern High Plains, Colorado Plateau, and Chihuahuan Desert) for a total of 208 evaluation plots. We also evaluated the repeatability of IIRH when applied to road-related disturbance gradients. Finally, we tested extent of correlations between IIRH plot attribute departure classes and trends in a suite of quantitative indicators. Results indicated that the IIRH technique is sensitive to direct and indirect impacts of transportation activities with greater departure from reference condition near disturbances than far from disturbances. Trends in degradation of ecological processes detected with qualitative assessments were highly correlated with quantitative data. Qualitative and quantitative assessments employed in this study can be used to assess impacts of transportation features at the plot scale. Through integration with remote sensing technologies, these methods could also potentially be used to assess cumulative impacts of transportation networks at the landscape scale.

Duniway, Michael C.; Herrick, Jeffrey E.; Pyke, David A.; Toledo, David

2010-01-01

343

Testing Method for Measuring Impact Strength of Bga Solder Joints on Electronic Package  

NASA Astrophysics Data System (ADS)

A pendulum-impact testing machine was developed to measure the impact strength of ball-grid-array (BGA) solder joints between an electronic package and a circuit board. Ball solders were connected to daisy-chain between a dummy electronic package and a circuit board. The upper side of the package was directly bonded to a load cell. The rear side of the circuit board was also bonded to an aluminum alloy block fixed on a base. A pendulum made of aluminum alloy was collided into the load cell to apply tensile impact to the solder joints through the load cell. The history of the impact load could be controlled by raising the angle of the pendulum. The fracture of a BGA solder joint was detected by measuring the resistance of the daisy-chain circuit on the board. Therefore, the impact strengths of the solder joints at electrical disconnection and mechanical breaking of all joints could be determined. The experimental results showed that this method is useful for measuring the impact strength of BGA solder joints.

Adachi, Tadaharu; Goto, Hirotaka; Araki, Wakako; Omori, Takahiro; Kawamura, Noriyasu; Mukai, Minoru; Kawakami, Takashi

344

Rapid impact testing for quantitative assessment of large populations of bridges  

NASA Astrophysics Data System (ADS)

Although the widely acknowledged shortcomings of visual inspection have fueled significant advances in the areas of non-destructive evaluation and structural health monitoring (SHM) over the last several decades, the actual practice of bridge assessment has remained largely unchanged. The authors believe the lack of adoption, especially of SHM technologies, is related to the 'single structure' scenarios that drive most research. To overcome this, the authors have developed a concept for a rapid single-input, multiple-output (SIMO) impact testing device that will be capable of capturing modal parameters and estimating flexibility/deflection basins of common highway bridges during routine inspections. The device is composed of a trailer-mounted impact source (capable of delivering a 50 kip impact) and retractable sensor arms, and will be controlled by an automated data acquisition, processing and modal parameter estimation software. The research presented in this paper covers (a) the theoretical basis for SISO, SIMO and MIMO impact testing to estimate flexibility, (b) proof of concept numerical studies using a finite element model, and (c) a pilot implementation on an operating highway bridge. Results indicate that the proposed approach can estimate modal flexibility within a few percent of static flexibility; however, the estimated modal flexibility matrix is only reliable for the substructures associated with the various SIMO tests. To overcome this shortcoming, a modal 'stitching' approach for substructure integration to estimate the full Eigen vector matrix is developed, and preliminary results of these methods are also presented.

Zhou, Yun; Prader, John; Devitis, John; Deal, Adrienne; Zhang, Jian; Moon, Franklin; Aktan, A. Emin

2011-03-01

345

Enhancements in Magnesium Die Casting Impact Properties  

SciTech Connect

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.

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

2000-06-30

346

Testing and injury potential analysis of rollovers with narrow object impacts.  

PubMed

Recent statistics highlight the significant risk of serious and fatal injuries to occupants involved in rollover collisions due to excessive roof crush. The government has reported that in 2002. Sports Utility Vehicle rollover related fatalities increased by 14% to more than 2400 annually. 61% of all SUV fatalities included rollovers [1]. Rollover crashes rely primarily upon the roof structures to maintain occupant survival space. Frequently these crashes occur off the travel lanes of the roadway and, therefore, can include impacts with various types of narrow objects such as light poles, utility poles and/or trees. A test device and methodology is presented which facilitates dynamic, repeatable rollover impact evaluation of complete vehicle roof structures with such narrow objects. These tests allow for the incorporation of Anthropomorphic Test Dummies (ATDs) which can be instrumented to measure accelerations, forces and moments to evaluate injury potential. High-speed video permits for detailed analysis of occupant kinematics and evaluation of injury causation. Criteria such as restraint performance, injury potential, survival space and the effect of roof crush associated with various types of design alternatives, countermeasures and impact circumstances can also be evaluated. In addition to presentation of the methodology, two representative vehicle crash tests are also reported. Results indicated that the reinforced roof structure significantly reduced the roof deformation compared to the production roof structure. PMID:15133990

Meyer, Steven E; Forrest, Stephen; Herbst, Brian; Hayden, Joshua; Orton, Tia; Sances, Anthony; Kumaresan, Srirangam

2004-01-01

347

Sport helmet design and virtual impact test by image-based finite element modeling.  

PubMed

Head injury has been a major concern in various sports, especially in contact sports such as football and ice hockey. Helmet has been adopted as a protective device in such sports, aiming at preventing or at least alleviating head injuries. However, there exist two challenges in current helmet design and test. One is that the helmet does not fit the subject's head well; the other is that current helmet testing methods are not able to provide accurate information about intracranial pressure and stress/strain level in brain tissues during impact. To meet the challenges, an image-based finite element modeling procedure was proposed to design subject-specific helmet and to conduct virtual impact test. In the procedure, a set of medical images such as computed tomography (CT) and magnetic resonance image (MRI) of the subject's head was used to construct geometric shape of the helmet and to develop a helmet-head finite element model that can be used in the virtual impact test. PMID:24111415

Luo, Yunhua; Liang, Zhaoyang

2013-07-01

348

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

Microsoft Academic Search

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

Chang-Lin Yeh; Yi-Shao Lai

2007-01-01

349

Proficiency testing as a tool for assessing the medical and economic impact of laboratory results: The blood coagulation case  

Microsoft Academic Search

An international commercial proficiency testing scheme was used to evaluate the impact of laboratory results on clinical decisions. The affect on atrial fibrillation was chosen as a model with 16 Israeli laboratories participating in an international study. A Markov model was constructed to evaluate the impact of any inaccurate results on the clinical outcomes. From the proficiency test study and

Orna Dreazen; Etty Feller; Moshe Leshno

2003-01-01

350

On the rate of growth and extent of the steady damage accumulation phase in repeated impact tests  

Microsoft Academic Search

In the paper, data of repeated impact tests performed on seven laminates of different lay-up and thickness are used to illustrate how the damage index (DI), a damage variable recently introduced by the authors to monitor the range of the penetration process in thick laminates, can be applied in case of repeated impact tests to get information on the rate

Giovanni Belingardi; Maria Pia Cavatorta; Davide Salvatore Paolino

2009-01-01

351

Application of the instrumented impact test to the study of the fracture of microalloyed steels for forging  

Microsoft Academic Search

One of the reasons why microalloyed steels for forging are not more widely used is that their toughness is lower than that of steel for hardening and tempering, especially when it is measured by the Charpy impact test. In order to achieve a better understanding of the behavior under impact of microalloyed steels for forging, Charpy tests were performed from

A. Herrero; J. M. Prado

1993-01-01

352

Evaluating the fracture properties and fatigue wear of tetrahedral amorphous carbon films on silicon by nano-impact testing  

Microsoft Academic Search

A repetitive contact technique, nano-impact testing, has been used to investigate the fracture properties of tetrahedral amorphous carbon (ta-C) thin films deposited on silicon by the filtered cathodic vacuum arc method. The impact test has shown clear differences in the resistance to impact wear of ta-C films with their thickness, for film thicknesses between 5 and 80 nm. The resistance

Ben D. Beake; S. P. Lau; James F. Smith

2004-01-01

353

High-speed 3-D kinematics from whole-body lateral impact sled tests.  

PubMed

While lateral impact sled studies have been conducted to determine injuries, injury mechanisms, and derive human tolerance using post mortem human subject (PMHS) for the chest and pelvis regions of the human body, there is a paucity of three-dimensional (3-D) motions at high-speeds. Since out-of-position occupants respond with 3-D motions even under pure frontal and lateral impacts, it is important to determine such kinematics at high-speeds in the temporal domain. Consequently, the objective of the study was to determine lateral impact-induced 3-D temporal motions at 1,000 frames per sec. PMHS were screened, seated on a sled, restrained using belt systems, and 13.5 g lateral impact acceleration was applied. Retroreflective photographic markers were placed at various locations including the head, first thoracic vertebra, sacrum, dorsal spine, and sled. 3-D coordinates of the anatomical locations of PMHS, fiducially placed markers, and sled were obtained pretest and post test. Kinematics of the head with respect to sled, head with respect to first thoracic vertebra, and first thoracic vertebra with respect to sled in the Cartesian system of reference were determined using a nine-camera system. Head and first thoracic vertebral kinematic data are reported in the paper. 3-D motions induced from lateral impacts supplement sensor-based data for improved crashworthiness evaluations. PMID:17487055

Yoganandan, Narayan; Pintar, Frank A; Gennarelli, Thomas A

2007-01-01

354

Impact testing to determine the mechanical properties of articular cartilage in isolation and on bone.  

PubMed

The biomechanical response of cartilage to impact loads, both in isolation and in situ on its bone substrate, has been little studied despite the common occurrence of osteoarthritis subsequent to cartilage injury. An instrumented drop tower was used to apply controlled impact loads of different energies to explants of bovine articular cartilage. Results were compared with a conventional slow stress-strain test. The effects of the underlying bone were investigated by progressively shortening a core of bone removed with the cartilage, and by gluing cartilage samples to substrates of different moduli. The maximum dynamic modulus of isolated samples of bovine articular cartilage, at strain rates between 1100 and 1500 s(-1), was approximately two orders of magnitude larger than the quasistatic modulus and varied non-linearly with applied stress. When attached to a substrate of higher modulus, increasing the thickness of the substrate increased the effective modulus of the combination until a steady value was achieved. A lower modulus substrate reduced the effective modulus of the combination. Severe impacts resulted in damage to the bone rather than to the cartilage. The modulus of cartilage rises rapidly and non-linearly with strain rate, giving the tissue a remarkable ability to withstand impact loads. The presence of cartilage attenuated the peak force experienced by the bone and spread the impact loading period over a longer time. PMID:17619965

Burgin, Leanne V; Aspden, Richard M

2007-07-10

355

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

SciTech Connect

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.

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

1996-12-01

356

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

PubMed

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

Vidair, Charles; Haas, Robert; Schlag, Robert

2007-12-01

357

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

Microsoft Academic Search

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

Fujun Yang; Siyuan Ni; Xiaoyuan He; Deping He

2008-01-01

358

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

Microsoft Academic Search

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

K S Vandersall; L L Switzer; F Garcia

2006-01-01

359

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

Microsoft Academic Search

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

QingHai Guo; KeMing Ma; Liu Yang; Kate He

2010-01-01

360

The effects of shock wave and quasi-traveling wave in the mechanical impact test  

Microsoft Academic Search

It is well-known that the numerical value is always larger than the measured value, amounting to many times, if we calculate\\u000a the stress of the specimen in the impulse test using the NASTRAN and ANSYS (N-A) software. We believe that the impact induces\\u000a shock wave or quasi-traveling wave in the specimen, which can qualitatively explain the discrepancy of the two

Mei Wu; ZhongFeng Sun; LuMei Zhang; Yong Chen; LinHong Ji

2010-01-01

361

The response of a high purity alumina to plate-impact testing  

Microsoft Academic Search

Alumina disks which were vacuum hot pressed from a 99.99% pure Al2O3 powder were subjected to flyer-plate impact testing. VISAR techniques were used to measure rear surface velocities. The Hugoniot elastic limit (HEL) for this alumina was 11.9 GPa. At a precompression of three times the HEL, a remarkably high spall strength of 1.2 GPa was observed. However, a negligible

J. M. Staehler; W. W. Predebon; B. J. Pletka

1994-01-01

362

Full-scale tornado-missile impact tests. Interim report. [Nuclear power plants  

Microsoft Academic Search

Seven completed initial tests are described with 4 types of hypothetical tornado-borne missiles (impacting reinforced concrete panels that are typical of walls in nuclear power facilities). The missiles were rocket propelled to velocities currently postulated as being attainable by debris in tornadoes. (1500-pound 35-foot long utility pole; 8-pound 1-inch Grade 60 reinforcing bar; 78-pound 3-inch Schedule 40 pipe; and 743-pound

1976-01-01

363

Does Volume of Patients Seen in an Outpatient Setting Impact Test Scores?  

Microsoft Academic Search

Background: Methods of teaching surgery in the outpatient setting and means to measure the effectiveness of these methods have not been defined. This study was designed to evaluate the impact of number of outpatient encounters on test scores for third-year medical students.Methods: Students rotating on the required third-year surgery clerkship between July 1994 and June 1996 kept a log of

Leigh Neumayer; Rose Marie McNamara; Merril Dayton; Benjamin Kim

1998-01-01

364

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

Microsoft Academic Search

Quasi-static uniform compression tests and low-velocity concentrated impact tests were conducted to reveal the failure mechanisms and energy absorption capacity of two-layer carbon fiber composite sandwich panels with pyramidal truss cores. Three different volume-fraction cores (i.e., with different relative densities) were fabricated: 1.25%, 1.81%, and 2.27%. Two-layer sandwich panels with identical volume-fraction cores (either 1.25% or 2.27%), and also stepwise

Jian Xiong; Ashkan Vaziri; Li Ma; Jim Papadopoulos; Linzhi Wu

365

Hypervelocity impact testing above 10 km/s of advanced orbital debris shields  

NASA Astrophysics Data System (ADS)

NASA has developed enhanced performance shields to improve the protection of spacecraft from orbital debris and meteoroid impacts. One of these enhanced shields includes a blanket of Nextel™ ceramic fabric and Kevlar™ high strength fabric that is positioned midway between an aluminum bumper and the spacecraft pressure wall. As part of the evaluation of this new shielding technology, impact data above 10 km/sec has been obtained by NASA Johnson Space Center (JSC) from the Sandia National Laboratories HVL (``hypervelocity launcher'') and the Southwest Research Institute inhibited shaped charge launcher (ISCL). The HVL launches flyer-plates in the velocity range of 10 to 15 km/s while the ISCL launches hollow cylinders at ~11.5 km/s. The >10 km/s experiments are complemented by hydrocode analysis and light-gas gun testing at the JSC Hypervelocity Impact Test Facility (HIT-F) to assess the effects of projectile shape on shield performance. Results from the testing and analysis indicate that the Nextel™/Kevlar™ shield provides superior protection performance compared to an all-aluminum shield alternative.

Christiansen, Eric L.; Crews, Jeanne Lee; Kerr, Justin H.; Chhabildas, Lalit C.

1996-05-01

366

The overall impact of testing on medical student learning: quantitative estimation of consequential validity.  

PubMed

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 the learning gains attained through educational assessments. To approach this question, we estimate achieved learning within a medical school environment that optimally utilizes educational assessments. We compare this estimate to learning that might be expected in a medical school that employs no educational assessments. Effect sizes are used to estimate testing's total impact on learning by summarizing three effects; the direct effect, the indirect effect, and the selection effect. The literature is far from complete, but the available evidence strongly suggests that each of these effects is large and the net cumulative impact on learning in medical education is over two standard deviations. While additional evidence is required, the current literature shows that testing within medical education makes a strong positive contribution to learning. PMID:22886140

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

2012-08-11

367

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

SciTech Connect

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 poor fitness of the impact-resistance test results produced in this study to normal distribution at 95% level of confidence for both fiber-reinforced and plain concrete. However, the percentage increase in number of blows from first crack to failure for both fiber-reinforced concrete and as well as plain concrete fit to normal distribution as indicated by the goodness-of-fit test. The coefficient of variation in percentage increase in the number of blows beyond first crack for fiber-reinforced concrete and plain concrete is 51.9 and 43.1%, respectively. Minimum number of tests required to reliably measure the properties of the material can be suggested based on the observed levels of variation.

Nataraja, M.C. [Sri Jayachamarajendra College of Engineering, Mysore (India). Faculty in Civil Engineering; Dhang, N.; Gupta, A.P. [Indian Inst. of Tech., Kharagpur (India). Dept. of Civil Engineering

1999-07-01

368

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

SciTech Connect

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.

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

2006-06-20

369

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

|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…

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

2011-01-01

370

The analysis of the microstructure changes of a Fe–Mn–Al alloy under dynamic impact tests  

Microsoft Academic Search

We studied the changes in microstructures of a Fe–Mn–Al alloy with a composition of Fe–32wt.% Mn–10wt.% Al–1.07wt.% C–0.36wt.% Mo under dynamic impact tests. We carried out the impact tests in a split Hopkinson bar tester as well as a universal tensile tester. We controlled the tests at room temperature and the strain rates were 1 × 10?3, 1.2 × 103,

Su-Tang Chiou; Wei-Chun Cheng; Woei-Shyan Lee

2004-01-01

371

Tensile and impact testing of an HFBR (High Flux Beam Reactor) control rod follower  

SciTech Connect

The Materials Technology Group of the Department of Nuclear Energy (DNE) at Brookhaven National Laboratory (BNL) undertook a program to machine and test specimens from a control rod follower from the High Flux Beam Reactor (HFBR). Tensile and Charpy impact specimens were machined and tested from non-irradiated aluminum alloys in addition to irradiated 6061-T6 from the HFBR. The tensile test results on irradiated material showed a two-fold increase in tensile strength to a maximum of 100.6 ksi. The impact resistance of the irradiated material showed a six-fold decrease in values (3 in-lb average) compared to similar non-irradiated material. Fracture toughness (K{sub I}) specimens were tested on an unirradiated compositionally and dimensionally similar (to HFBR follower) 6061 T-6 material with K{sub max} values of 24.8 {plus minus} 1.0 Ksi{radical}in (average) being obtained. The report concludes that the specimens produced during the program yielded reproducible and believable results and that proper quality assurance was provided throughout the program. 9 figs., 6 tabs.

Czajkowski, C.J.; Schuster, M.H.; Roberts, T.C.; Milian, L.W.

1989-08-01

372

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

PubMed

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

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

2011-05-23

373

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

NASA Astrophysics Data System (ADS)

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.

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

2011-05-01

374

Single particle impact tests using gas gun and analysis of high strain-rate impact events in ductile materials  

Microsoft Academic Search

Removal of material by the action of impinging particles is known as erosion. Based on the understanding of the material removal mechanisms in ductile materials, in normal impact, material removal occurs predominantly by deformation whereas in oblique impacts, material is removed through a combination of cutting and deformation. Although material can be removed in cutting by a single impact, material

A. A. Cenna; N. W. Page; E. Kisi; M. G. Jones

2011-01-01

375

Impact of the emergence of designer drugs upon sports doping testing.  

PubMed

Historically, dope-testing methods have been developed to target specific and known threats to the integrity of sport. Traditionally, the source of new analytical targets for which testing was required were derived almost exclusively from the pharmaceutical industry. More recently, the emergence of designer drugs, such as tetrahydrogestrinone that are specifically intended to evade detection, or novel chemicals intended to circumvent laws controlling the sale and distribution of recreational drugs, such as anabolic steroids, stimulants and cannabinoids, have become a significant issue. In this review, we shall consider the emergence of designer drugs and the response of dope-testing laboratories to these new threats, in particular developments in analytical methods, instrumentation and research intended to detect their abuse, and we consider the likely future impact of these approaches. PMID:22191595

Teale, P; Scarth, J; Hudson, S

2012-01-01

376

Force reconstruction for impact tests of an energy-absorbing nose  

SciTech Connect

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.

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

1990-01-01

377

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

SciTech Connect

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.

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

1996-06-01

378

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

PubMed Central

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.

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

2011-01-01

379

BRCA1/2 Test Results Impact Risk Management Attitudes, Intentions and Uptake  

PubMed Central

BACKGROUND Women who receive positive or uninformative BRCA1/2 test results face a number of decisions about how to manage their cancer risk. The purpose of this study was to prospectively examine the effect of receiving a positive vs. uninformative BRCA1/2 genetic test result on the perceived pros and cons of risk-reducing mastectomy (RRM) and risk-reducing oophorectomy (RRO) and breast cancer screening. We further examined how perceived pros and cons of surgery predict intention for and uptake of surgery. METHODS 308 women (146 positive, 162 uninformative) were included in RRM and breast cancer screening analyses. 276 women were included in RRO analyses. Participants completed questionnaires at pre-disclosure baseline and 1-, 6-and 12-months post-disclosure. We used linear multiple regression to assess whether test result contributed to change in pros and cons and logistic regression to predict intentions and surgery uptake. RESULTS Receipt of a positive BRCA1/2 test result predicted stronger pros for RRM and RRO (Ps < .001), but not perceived cons of RRM and RRO. Pros of surgery predicted RRM and RRO intentions in carriers and RRO intentions in uninformatives. Cons predicted RRM intentions in carriers. Pros and cons predicted carriers’ RRO uptake in the year after testing (Ps < .001). CONCLUSIONS Receipt of BRCA1/2 mutation test results impacts how carriers see the positive aspects of RRO and RRM and their surgical intentions. Both the positive and negative aspects predict uptake of surgery.

O'Neill, Suzanne C.; Valdimarsdottir, Heiddis B.; DeMarco, Tiffani A.; Peshkin, Beth N.; Graves, Kristi D.; Brown, Karen; Hurley, Karen E.; Isaacs, Claudine; Hecker, Sharon; Schwartz, Marc D.

2011-01-01

380

Side Impact Response Corridors for the Rigid Flat-Wall and Offset-Wall Side Impact Tests of NHTSA Using the ISO Method of Corridor Development.  

PubMed

The purpose of this paper is to compare the biofidelity rating schemes of ISO/TR9790 and the NHTSA Bio Rank System. This paper describes the development of new impact response corridors being proposed for ISO/TR9790 from the results of a recent series of side-impact sled tests. The response data were analyzed by methods consistent with ISO/TR9790, including normalization by impulse-momentum analysis and the elimination of subjects that sustained six or more rib fractures. Unlike ISO/TR9790, this paper proposes the elimination of the data from tests in which the timing and the sequence of loading of the individual impact plates were inconsistent compared to other tests conducted with the same impact wall configuration. As a result of differences in the analysis methods, data selection criteria, and the method of corridor construction, the impact response corridors proposed here are different from those developed by NHTSA, despite the fact that both sets of corridors were developed from the same series of sled tests. Responses of the ES-2 and ES-2re side impact dummies are compared to both sets of corridors. The response corridors developed in this paper are proposed as an addition to and not a replacement for those given in the 1999 revision of ISO/TR9790. PMID:17096284

Irwin, Annette L; Sutterfield, Aleta; Hsu, Timothy P; Kim, Agnes; Mertz, Harold J; Rouhana, Stephen W; Scherer, Risa

2005-11-01

381

Nano-impact testing of TiFeN and TiFeMoN films for dynamic toughness evaluation  

NASA Astrophysics Data System (ADS)

TiFeN and TiFeMoN films were deposited on silicon wafers by ion-beam-assisted deposition. Their mechanical properties were measured by nanoindentation (quasi-static) and nano-impact (dynamic) techniques. Nano-impact testing enabled assessment of their toughness and resistance to fatigue fracture under repetitive loading. At low impact forces, films with a higher resistance to plastic deformation (H3/E2) were much more resistant to the formation of cracks throughout the test. At higher impact forces, these films initially show impact resistance but with continued impacts they are unable to protect the Si substrate, performing as poorly as films with lower H3/E2 and suffer delamination from the Si substrate over a large area.

Beake, B. D.; Vishnyakov, V. M.; Colligon, J. S.

2011-03-01

382

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

SciTech Connect

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.

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

1998-10-21

383

Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) Practices of Sports Medicine Professionals  

PubMed Central

Abstract Context: Computerized neurocognitive testing is becoming popular among clinicians evaluating sport-related concussions across all levels of sport. Baseline neurocognitive testing has been recommended to provide more accurate representation of the preconcussion cognitive status of individual athletes. However, little is known about the use of baseline neurocognitive testing in concussion assessment and management. Objective: To examine implementation and practice trends of sports medicine professionals using baseline neurocognitive testing at the high school and collegiate levels. Design: Quantitative survey research. Setting: Online survey. Patients or Other Participants: Certified athletic trainers (ATs) from approximately 1209 US institutions listed on the ImPACT Web site were recruited. A total of 399 ATs completed the survey, for a response return rate of 32.7%. Main Outcome Measure(s): Survey questions addressed educational level, years of certification, employment setting, percentage of athletes baseline tested, and accuracy of baseline tests. Other items addressed postconcussive neurocognitive testing protocols and scenarios for return-to-play decisions based on neurocognitive testing. Results: Nearly all ATs (94.7%) administered baseline computerized neurocognitive testing to their athletes. However, only 51.9% examined these baseline tests for validity. The majority of ATs indicated that they administer baseline neurocognitive tests most frequently to football players (88.4%), followed by women's soccer players (78.8%) and men's soccer players (71.2%). Nearly all respondents (95.5%) stated that they would not return a symptomatic athlete to play if the athlete's neurocognitive scores were back to baseline. However, when asked if they would return an athlete who is symptom free but who scores below his or her baseline, 86.5% responded no, 9.8% responded yes, and 3.8% indicated that it depended on the importance of the competition. Conclusions: The use of baseline testing, baseline testing readministration, and postconcussion protocols among ATs is increasing. However, the ATs in this study reported that they relied more on symptoms than on neurocognitive test scores when making return-to-play decisions.

Covassin, Tracey; Elbin, Robert J.; Stiller-Ostrowski, Jennifer L.; Kontos, Anthony P.

2009-01-01

384

Analysis of catalyst particle strength by impact testing: The effect of manufacturing process parameters on the particle strength  

Microsoft Academic Search

The mechanical strength of porous alumina catalyst carrier beads, used in the reforming units with continuous catalytic regeneration, was measured by impact testing. With this testing method particle strength can be measured at higher strain rates than the traditional crushing test method, hence providing a better simulation of pneumatic conveying and chute flow conditions, and also a large number of

Charlotte Subero-Couroyer; Mojtaba Ghadiri; Nathalie Brunard; Frédéric Kolenda

2005-01-01

385

Mechanisms of Energy Dissipation in the Process of Impact Testing of Carbon-Filled Plastics Based on Phenylone  

Microsoft Academic Search

We present the results of impact testing of carbon-filled plastics based on phenylone. It is shown that, in carbon-filled plastics based on phenylone, the role of dissipators of impact energy is played by porously packed regions of the three-dimensional polymeric matrix and the interphase regions. It is demonstrated that the impact energy dissipates according to the following two mechanisms: molecular

O. I. Burya; H. V. Kozlov; O. P. Chyhvintseva

2005-01-01

386

Nano-impact testing of TiFeN and TiFeMoN films for dynamic toughness evaluation  

Microsoft Academic Search

TiFeN and TiFeMoN films were deposited on silicon wafers by ion-beam-assisted deposition. Their mechanical properties were measured by nanoindentation (quasi-static) and nano-impact (dynamic) techniques. Nano-impact testing enabled assessment of their toughness and resistance to fatigue fracture under repetitive loading. At low impact forces, films with a higher resistance to plastic deformation (H3\\/E2) were much more resistant to the formation of

B. D. Beake; V. M. Vishnyakov; J. S. Colligon

2011-01-01

387

Failure mode analysis of lead-free solder joints under differential reflow profiles by high speed impact testing  

Microsoft Academic Search

The aim of this research is to investigate the mechanical behavior of lead-free solder for high speed impact. A high speed impact test was set up to measure the solder joint reliability. Differential impact speed and room temperature aging effect has been studied with Ni\\/Au substrate. Furthermore, two different solder alloys (96.5Sn-3Ag-0.5Cu, 98.5Sn-1Ag-0.5C) and three different reflow profiles are considered.

C. Y. Lin; Y. R. Chen; G. S. Shen; D. S. Liu; C. Y. Kuo; C. L. Hsu

2008-01-01

388

Miniaturized Compression Test at Very High Strain Rates by Direct Impact  

Microsoft Academic Search

A modified miniaturized version of the Direct Impact Compression Test (DICT) technique is described in this paper. The method\\u000a permits determination of the rate-sensitive plastic properties of materials up to strain rate ?105 s?1. Miniaturization of the experimental setup with specimen dimensions: diameter d\\u000a S?=?2.0 mm and thickness l\\u000a S?=?1.0 mm, Hopkinson bar diameter 5.2 mm, with application of a novel optical arrangement in

J. Z. Malinowski; J. R. Klepaczko; Z. L. Kowalewski

2007-01-01

389

Impact of Imperfect Test Sensitivity on Determining Risk Factors: The Case of Bovine Tuberculosis  

PubMed Central

Background Imperfect diagnostic testing reduces the power to detect significant predictors in classical cross-sectional studies. Assuming that the misclassification in diagnosis is random this can be dealt with by increasing the sample size of a study. However, the effects of imperfect tests in longitudinal data analyses are not as straightforward to anticipate, especially if the outcome of the test influences behaviour. The aim of this paper is to investigate the impact of imperfect test sensitivity on the determination of predictor variables in a longitudinal study. Methodology/Principal Findings To deal with imperfect test sensitivity affecting the response variable, we transformed the observed response variable into a set of possible temporal patterns of true disease status, whose prior probability was a function of the test sensitivity. We fitted a Bayesian discrete time survival model using an MCMC algorithm that treats the true response patterns as unknown parameters in the model. We applied our approach to epidemiological data of bovine tuberculosis outbreaks in England and investigated the effect of reduced test sensitivity in the determination of risk factors for the disease. We found that reduced test sensitivity led to changes to the collection of risk factors associated with the probability of an outbreak that were chosen in the ‘best’ model and to an increase in the uncertainty surrounding the parameter estimates for a model with a fixed set of risk factors that were associated with the response variable. Conclusions/Significance We propose a novel algorithm to fit discrete survival models for longitudinal data where values of the response variable are uncertain. When analysing longitudinal data, uncertainty surrounding the response variable will affect the significance of the predictors and should therefore be accounted for either at the design stage by increasing the sample size or at the post analysis stage by conducting appropriate sensitivity analyses.

Szmaragd, Camille; Green, Laura E.; Medley, Graham F.; Browne, William J.

2012-01-01

390

Body Image: Impacts of Media Channels on Men's and Women's Social Comparison Process, and Testing of Involvement Measurement  

Microsoft Academic Search

This study examines the impacts of social comparison processes on men and women to investigate any potential gender differences by utilizing survey research (N = 134). This study also investigates the different impacts of magazine and television social comparison processes on men's and women's body perceptual gap and body satisfaction. Last, this study tests the validity of a new scale

Steve H. Sohn

2009-01-01

391

A study of the feasibility of Internet administration of a computerized health survey: The headache impact test (HIT™)  

Microsoft Academic Search

Background: Headache impact test (HIT™) is a precise, practical tool that quantifies the impact of headache on respondents' lives. It is the first widely-available dynamic health assessment (DynHA™). Applications of this brief, precise survey include population based screening for disabling headaches, tracking of individual patient scores over time, disease management programs and others. We use data from Internet HIT assessments

M. S. Bayliss; J. E. Dewey; I. Dunlap; A. S. Batenhorst; R. Cady; M. L. Diamond; F. Sheftell

2003-01-01

392

Comparison of mechanical response of PCBs subjected to product-level and board-level drop impact tests  

Microsoft Academic Search

Portable electronic products such as mobile phones are susceptible to drop impacts. Consequently, the effects of impact and shock on the integrity of the electronic components on a printed circuit board (PCB) are important mechanical reliability issues that need to be addressed, Mechanical shock tests for electronic components generally fall into two categories: board-level and product-level. The most realistic shock

Y. C. Ong; V. P. W. Shim; T. C. Chai; C. T. Lim

2003-01-01

393

Analytical impact models and experimental test validation for the Columbia shuttle wing leading edge panels.  

SciTech Connect

This paper describes the analyses and the experimental mechanics program to support the National Aeronautics and Space Administration (NASA) investigation of the Shuttle Columbia accident. A synergism of the analysis and experimental effort is required to insure that the final analysis is valid - the experimental program provides both the material behavior and a basis for validation, while the analysis is required to insure the experimental effort provides behavior in the correct loading regime. Preliminary scoping calculations of foam impact onto the Shuttle Columbia's wing leading edge determined if enough energy was available to damage the leading edge panel. These analyses also determined the strain-rate regimes for various materials to provide the material test conditions. Experimental testing of the reinforced carbon-carbon wing panels then proceeded to provide the material behavior in a variety of configurations and strain-rates for flown or conditioned samples of the material. After determination of the important failure mechanisms of the material, validation experiments were designed to provide a basis of comparison for the analytical effort. Using this basis, the final analyses were used for test configuration, instrumentation location, and calibration definition in support of full-scale testing of the panels in June 2003. These tests subsequently confirmed the accident cause.

Lu, Wei-Yang; Metzinger, Kurt Evan; Gwinn, Kenneth West; Antoun, Bonnie R.; Korellis, John S.

2004-10-01

394

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

SciTech Connect

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.

NSTec Environmental Restoration

2009-06-01

395

Assessment of the TASER XREP blunt impact and penetration injury potential using cadaveric testing.  

PubMed

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

Lucas, Scott R; McGowan, Joseph C; Lam, Tack C; Yamaguchi, Gary T; Carver, Matthew; Hinz, Andrew

2012-10-15

396

Impact of time-dependency on long-term material testing and modeling of polyethylene  

NASA Astrophysics Data System (ADS)

Ultra-high molecular weight polyethylene (UHMWPE) has an important role in orthopaedic implants because of its favorable properties as an articulating surface. UHMWPE component testing often focuses on measuring the long-term fatigue or wear response of the material that could be realized during many years of use. However, the impact of time-dependent properties of UHMWPE on such tests is not well characterized. In particular, altering the frequency of loading and allowing for material creep or relaxation can significantly alter the stress/strain state of the material, and therefore affect long-term mechanical properties (e.g. wear, fatigue) that are dependent on the constitutive state. The goal of this work is to use advanced, validated material modeling of UHMPWE that incorporates time-dependent properties to explore the effects of frequency and rest time on the mechanical response of UHMWPE.

Bischoff, Jeffrey E.

2008-09-01

397

Impact of technical training on rapid antigen detection tests (RADT) in group A streptococcal tonsillopharyngitis.  

PubMed

Rapid antigen detection tests (RADT) are widely used for the rapid diagnosis of group A streptococcal (GAS) tonsillopharyngitis. In a prospective 3-year study, the reliability of two different RADT methods was compared, as performed by lab technicians versus physicians. Sensitivity and specificity, as well as positive and negative predictive values, were calculated. When performed by physicians, the results (44.4 %, 8.3 %, 26.7 % and 16.7 %) of a latex agglutination test (LAT) were unacceptably low. However, after switching to a lateral-flow immunoassay (LFIT) and implementing additional hands-on training, the performance improved dramatically (100 %, 92.6 %, 84.6 % and 100 %). In conclusion, technical errors, along with a lack of experience and expertise, negatively impact RADT accuracy. PMID:23207649

Toepfner, N; Henneke, P; Berner, R; Hufnagel, M

2012-12-04

398

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

Microsoft Academic Search

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

Jeongmin Lee; Oakkey Min

1995-01-01

399

Brittle–ductile transition of PP\\/POE blends in both impact and high speed tensile tests  

Microsoft Academic Search

Polypropylene (PP)\\/octene-ethylene copolymer (POE) blends were studied in both impact and high speed tensile tests, in which the practical strain rate was 208\\/s. With the increase of the POE content, brittle–ductile transition (BDT) of PP\\/POE blends occurred in both the impact and high speed tensile tests. BDT also occurred with the decrease of the tensile speed when any of the

Jinhai Yang; Yong Zhang; Yinxi Zhang

2003-01-01

400

Exploratory behaviour in the open field test adapted for larval zebrafish: impact of environmental complexity.  

PubMed

This study aimed to develop and characterize a novel (standard) open field test adapted for larval zebrafish. We also developed and characterized a variant of the same assay consisting of a colour-enriched open field; this was used to assess the impact of environmental complexity on patterns of exploratory behaviours as well to determine natural colour preference/avoidance. We report the following main findings: (1) zebrafish larvae display characteristic patterns of exploratory behaviours in the standard open field, such as thigmotaxis/centre avoidance; (2) environmental complexity (i.e. presence of colours) differentially affects patterns of exploratory behaviours and greatly attenuates natural zone preference; (3) larvae displayed the ability to discriminate colours. As reported previously in adult zebrafish, larvae showed avoidance towards blue and black; however, in contrast to the reported adult behaviour, larvae displayed avoidance towards red. Avoidance towards yellow and preference for green and orange are shown for the first time, (4) compared to standard open field tests, exposure to the colour-enriched open field resulted in an enhanced expression of anxiety-like behaviours. To conclude, we not only developed and adapted a traditional rodent behavioural assay that serves as a gold standard in preclinical drug screening, but we also provide a version of the same test that affords the possibility to investigate the impact of environmental stress on behaviour in larval zebrafish while representing the first test for assessment of natural colour preference/avoidance in larval zebrafish. In the future, these assays will improve preclinical drug screening methodologies towards the goal to uncover novel drugs. This article is part of a Special Issue entitled: insert SI title. PMID:23123970

Ahmad, Farooq; Richardson, Michael K

2012-11-01

401

Summary and evaluation of low-velocity impact tests of solid steel billet onto concrete pads  

SciTech Connect

Spent fuel storage casks intended for use at independent spent fuel storage installations are evaluated during the application and review process for low-velocity impacts representative of possible handling accidents. In the past, the analyses involved in these evaluations have assumed that the casks dropped or tipped onto an unyielding surface - a conservative and simplifying assumption. Since 10 CFR Part 72, the regulation imposed by the Nuclear Regulatory Commission (NRC), does not require this assumption, applicants are currently seeking a more realistic model for the analyses to predict the effect of a cask dropping onto a reinforced concrete pad, including energy absorbing aspects such as cracking and flexure. To develop data suitable for benchmarking these analyses, the NRC has conducted several series of drop-test studies of a solid steel billet and of a near-full-scale empty cask. This report contains a summary and evaluation of all steel billet testing conducted by Sandia National Laboratories and Lawrence Livermore National Laboratory. A series of finite element analyses of the billet testing is described and benchmarked against the test data. A method to apply the benchmarked finite element model of the soil and concrete pad to an analysis of a full-size storage cask is provided. In addition, an application to a {open_quotes}generic{close_quotes} full-size cask is presented for side and end drops, and tipover events. The primary purpose of this report is to provide applicants for an NRC license under 10 CFR Part 72 with a method for evaluating storage casks for low-velocity impact conditions.

Witte, M.C.; Hovingh, W.J.; Mok, G.C.; Murty, S.S.; Chen, T.F.; Fischer, L.E.

1998-02-01

402

Instrumented impact testing of fabric-reinforced composite materials. Research and development report  

Microsoft Academic Search

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

T. D. Juska; R. M. Crane; T. Mixon

1989-01-01

403

Investigation of Steven Impact Test Using a Transportation Hook Projectile with Gauged Experiments and 3D Modeling  

NASA Astrophysics Data System (ADS)

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.

Vandersall, Kevin S.; Murty, Susarla S.; Chidester, Steven K.; Forbes, Jerry W.; Garcia, Frank; Greenwood, Daniel W.; Tarver, Craig M.

2004-07-01

404

The performance assessment impacts of disposal of high-moisture, low-level radioactive waste at the Nevada Test Site  

SciTech Connect

A panel of independent scientists was convened by the Department of Energy to assess the performance impacts of disposal of low-level radioactive waste from the Fernald Environmental Management Project. This waste stream was involved in a transportation incident in December 1997. A resulting outgrowth of investigations of the transportation incident was the recognition that the waste was transported and disposed in stress-fractured metal boxes and some of the waste contained excess moisture (high volumetric water contents). The panel was charged with determining whether disposal of this waste in the Area 5 radioactive waste management site on the Nevada Test Site has impacted the conclusions of the completed performance assessment. Three questions were developed by the panel to assess performance impacts: (1) the performance impacts of reduced container integrity, (2) the impact of reduced container integrity on subsidence of waste in the disposal pits and (3) the performance impacts of excess moisture. No performance or subsidence impacts were noted from disposal of the Fernald waste. The impacts of excess moisture were assessed through simulation modeling of the movement of moisture in the vadose zone assuming high water contents (wet waste) for different percentages of the waste inventory. No performance impacts were noted for either the base-case scenario (ambient conditions) or a scenario involving subsidence and flooding of the waste cells. The absence of performance impacts results form the extreme conservatism used in the Area 5-performance assessment and the robust nature of the disposal site.

Crowe, B.M.; Hansen, W. [Los Alamos National Lab., NM (United States); Hechnova, A. [Univ. of Nevada, Las Vegas, NV (United States). Harry Reid Center of Environmental Studies; Jacobson, R. [Desert Research Inst., Reno, NV (United States); Voss, C. [Golder Associates, Inc. (United States); Waters, R. [Sandia National Labs., Albuquerque, NM (United States); Sully, M.; Levitt, D. [Bechtel Nevada, Las Vegas, NV (United States)

1999-03-01

405

Development of small punch testing technique and its application to evaluation of mechanical properties degradation  

SciTech Connect

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.

Kameda, J.

1993-10-01

406

Development of small punch testing technique and its application to evaluation of mechanical properties degradation  

NASA Astrophysics Data System (ADS)

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.

Kameda, J.

407

The impact of target luminance and radiance on night vision device visual performance testing  

NASA Astrophysics Data System (ADS)

Visual performance through night-vision devices (NVDs) is a function of many parameters such as target contrast, objective and eyepiece lens focus, signal/noise of the image intensifier tube, quality of the image intensifier, night-vision goggle (NVG) gain, and NVG output luminance to the eye. The NVG output luminance depends on the NVG sensitive radiance emitted (or reflected) from the visual acuity target (usually a vision testing chart). The primary topic of this paper is the standardization (or lack thereof) of the radiance levels used for NVG visual acuity testing. The visual acuity chart light level might be determined in either photometric (luminance) units or radiometric (radiance) units. The light levels are often described as "starlight," "quarter moon," or "optimum" light levels and may not actually provide any quantitative photometric or radiometric information. While these terms may be useful to pilots and the users of night-vision devices, they are inadequate for accurate visual performance testing. This is because there is no widely accepted agreement in the night vision community as to the radiance or luminance level of the target that corresponds to the various named light levels. This paper examines the range of values for "starlight," "quarter moon," and "optimum" light commonly used by the night vision community and referenced in the literature. The impact on performance testing of variations in target luminance/radiance levels is also examined. Arguments for standardizing on NVG-weighted radiometric units for testing night-vision devices instead of photometric units are presented. In addition, the differences between theoretical weighted radiance and actual weighted radiance are also discussed.

Marasco, Peter L.; Task, H. Lee

2003-09-01

408

Urineschool: A Study of the Impact of the Earls Decision on High School Random Drug Testing Policies.  

ERIC Educational Resources Information Center

Examines impact of Supreme Court's 2002 decision in "Board of Education v. Earls" on high school random drug-testing policies and practices. Court held that random drug-testing policy at Tecumseh, Oklahoma, school district did not violate students' Fourth Amendment right against unreasonable searches. (Contains 46 references.) (PKP)

Conlon, Cynthia Kelly

2003-01-01

409

Social interactions in adolescent and adult Sprague–Dawley rats: Impact of social deprivation and test context familiarity  

Microsoft Academic Search

Interactions with peers become particularly important during adolescence, and age differences in social interactions have been successfully modeled in rats. To determine the impact of social deprivation on social interactions under anxiogenic (unfamiliar) or non-anxiogenic (familiar) test circumstances during ontogeny, the present study used a modified social interaction test to assess the effects of 5 days of social isolation or

Elena I. Varlinskaya; Linda P. Spear

2008-01-01

410

On the Modeling of Electric Railway Lines for the Assessment of Infrastructure Impact in Radiated Emission Tests of Rolling Stock  

Microsoft Academic Search

In this paper, we address the problem of testing radiated emissions generated by rolling stock, when carried out on actual railway sites, as prescribed by the standard EN 50121. The idea of assessing infrastructure impact on test results is presented here by means of an electromagnetic model of railway sites. In the first part, modeling tools are introduced together with

Andrea Cozza; Bernard DÉmoulin

2008-01-01

411

Pickup and Van Side Structure Baseline Assessment. Test No. 4. Vehicle-to-Vehicle 60 degree Right Side Impact.  

National Technical Information Service (NTIS)

The objective of the test was to provide baseline data for an unmodified pickup truck when involved in a 60 degree right side vehicle-to-vehicle impact crash. For this test, the target vehicle was stationary and set at 60 degrees to the line of travel of ...

M. Pozzi

1980-01-01

412

Charpy impact test of Ti-6Al-4V joints diffusion welded at low temperature  

SciTech Connect

The Diffusion Welding (DW) of two or more sheets of Ti-6Al-4V alloy is particularly interesting for aerospace parts manufacturing. In some cases, DW can be carried out together with Superplastic Forming (SPF), because they can share a single facility and the same processing parameters, such as temperature, pressure, time, surface condition and vacuum. The overall manufacturing process is known as SPF/DW, by which it is possible to obtain honeycomb structures in a range of designs. Temperature requirements for industrial SPF of Ti-6Al-4V are very restrictive and a temperature of 1,023 K is needed. However, temperature is not so critical for DW, and the bond can be produced at lower temperatures, when other DW parameters, mainly pressure and time, are changed in a suitable way. The DW parameters for this research were chosen in order to produce DW joints below 1,023 K. The differences between DW at SPF temperatures and other lower temperatures would thus be revealed. Mechanical tests were used as a tool to check DW joints obtained at the temperatures used in the research (1,123 K and 1,023 K), and were complemented with metallographic studies. The results obtained form shear and peel tests have been already discussed. In the present work the results of impact energy tests are also presented.

Salazar, J.M.G. de; Urena, A. [Complutense Univ. of Madrid (Spain); Carrion, J.G. [National Inst. of Aeroespatial Technologies, Madrid (Spain). Materials and Structures Div.

1996-08-15

413

25.0 MPH 26 deg Crabbed Moving Barrier Impact Tests into a 26 deg Load Cell Barrier Face. Test-1; NHTSA (National Highway Traffic Safety Administration) Deformable Barrier Face. Test-2; EEVC Deformable Barrier Face.  

National Technical Information Service (NTIS)

The test report documents two (2) crash tests using the 26 deg crabbed moving barrier impacting into the load cell barrier mounted at a 26 deg angle. The tests were conducted as part of a program to assess the differences between the NHTSA and EEVC Deform...

N. A. El-Habash

1987-01-01

414

Pharmacogenetics and population pharmacokinetics: impact of the design on three tests using the SAEM algorithm.  

PubMed

Pharmacogenetics is now widely investigated and health institutions acknowledge its place in clinical pharmacokinetics. Our objective is to assess through a simulation study, the impact of design on the statistical performances of three different tests used for analysis of pharmacogenetic information with nonlinear mixed effects models: (i) an ANOVA to test the relationship between the empirical Bayes estimates of the model parameter of interest and the genetic covariate, (ii) a global Wald test to assess whether estimates for the gene effect are significant, and (iii) a likelihood ratio test (LRT) between the model with and without the genetic covariate. We use the stochastic EM algorithm (SAEM) implemented in MONOLIX 2.1 software. The simulation setting is inspired from a real pharmacokinetic study. We investigate four designs with N the number of subjects and n the number of samples per subject: (i) N = 40/n = 4, similar to the original study, (ii) N = 80/n = 2 sorted in 4 groups, a design optimized using the PFIM software, (iii) a combined design, N = 20/n = 4 plus N = 80 with only a trough concentration and (iv) N = 200/n = 4, to approach asymptotic conditions. We find that the ANOVA has a correct type I error estimate regardless of design, however the sparser design was optimized. The type I error of the Wald test and LRT are moderatly inflated in the designs far from the asymptotic (<10%). For each design, the corrected power is analogous for the three tests. Among the three designs with a total of 160 observations, the design N = 80/n = 2 optimized with PFIM provides both the lowest standard error on the effect coefficients and the best power for the Wald test and the LRT while a high shrinkage decreases the power of the ANOVA. In conclusion, a correction method should be used for model-based tests in pharmacogenetic studies with reduced sample size and/or sparse sampling and, for the same amount of samples, some designs have better power than others. PMID:19562469

Bertrand, Julie; Comets, Emmanuelle; Laffont, Céline M; Chenel, Marylore; Mentré, France

2009-06-27

415

Force corridors of post mortem human surrogates in oblique side impacts from sled tests.  

PubMed

To develop region-specific force corridors in side impacts under oblique loadings using post mortem human surrogates (PMHS). Unembalmed PMHS were positioned on a sled. Surrogates contacted a segmented, modular/ scalable load-wall to isolate region-specific forces (shoulder, thorax, abdomen, pelvis). Heights and widths of segmented load-wall plates were adjustable in sagittal and coronal planes to accommodate anthropometry variations. Load cells were used to gather region-specific forces. Tests were conducted at 6.7 m/s. Peak forces and times of attainments, and standard corridors (mean ± 1 SD) are given for the four torso regions and summated forces. The mean age, stature, and total body mass of the five male PMHS were: 56.6 ± 4.4 years, 183 ± 3.5 cm and 70.6 ± 9.0 kg. Peak pelvis forces were the greatest, followed by thorax, abdomen and shoulder. Sequence of times of attainments of peak forces initiating from pelvis increased rostrally to abdomen to thorax and shoulder regions. Corridors were tight in all regions, except shoulder. As previous force corridors were based solely on pure-lateral impacts and region-specific forces were not extracted, the present oblique responses using anthropometry-specific load-wall design can be used to develop injury criteria and evaluate the biofidelity of dummies. PMID:23817764

Yoganandan, Narayan; Humm, John R; Pintar, Frank A

2013-07-02

416

High-silicon {sup 238}PuO{sub 2} fuel characterization study: Half module impact tests  

SciTech Connect

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. The modular GPHS design was developed to address both survivability during launch abort and return from orbit. Previous testing conducted in support of the Galileo and Ulysses missions documented the response of GPHSs to a variety of fragment- impact, aging, atmospheric reentry, and Earth-impact conditions. The evaluations documented in this report are part of an ongoing program to determine the effect of fuel impurities on the response of the heat source to conditions baselined during the Galileo/Ulysses test program. In the first two tests in this series, encapsulated GPHS fuel pellets containing high levels of silicon were aged, loaded into GPHS module halves, and impacted against steel plates. The results show no significant differences between the response of these capsules and the behavior of relatively low-silicon fuel pellets tested previously.

Reimus, M.A.H.

1997-01-01

417

Impact of erosion testing aspects on current and future flight conditions  

NASA Astrophysics Data System (ADS)

High speed of aero vehicles including commercial and military aircraft, missiles, unmanned air vehicles, as well as conceptual aircraft of the future are imposing larger restrictions on the materials of these vehicles and highlight the importance of adequate quantification of material behavior and performance during different flight conditions. Erosion due to weather conditions and other present particles such as hydrometeors; rain, hail and ice, as well as sand, volcanic ash and dust resulting from residues in the atmosphere are eminent as hazardous on the structure of a flying vehicle and may adversely influence the lifecycle of the structure. This study outlines an extensive review of research efforts on erosion in aviation and provides a basis for comparison between different apparatus simulating rain erosion and their usage within the aerospace industry. The significant aspects of erosion testing and future prospects for erosion impact are further addressed for forthcoming generations of flying vehicles.

Gohardani, Omid

2011-05-01

418

Object Shape Reconstruction with MER Navcam and Pancam: Testing Science Impacts of Known Stereo Algorithm Constraints  

NASA Astrophysics Data System (ADS)

The Mars Exploration Rover (MER) stereo imaging system (Pancam, Navcam, and Hazcam) has been calibrated and validated primarily for the purposes of rover navigation, robotic arm control, and targeted instrument remote sensing. While the stereo data sets have been extensively characterized for the surface operation of the MER vehicles, to date there has not been a systematic study on the use of the stereo data for scientific investigations. Moreover, the MER PDS archives do not describe the error propagation into the XYZ data. Since stratigraphy and rock shape analyses are being done with MER data, and since photometry is particularly sensitive to slope and topographic roughness, we have carried out tests with engineering model cameras using real shape targets to check the impact of known stereo correlation algorithm 'features' to the possible interpretation of the XYZ data. Comparison of high resolution laser scan DEMs of our targets with stereo XYZ data products will be presented at the meeting.

Anderson, R. C.; Bornstein, B. J.; Haldemann, A. F.; Estlin, T. A.; Maki, J.; Petras, R. D.; Castano, R.; Judd, M. A.; Golombek, M. P.

2006-12-01

419

A grindability test to study the influence of material processing on impact behaviour  

Microsoft Academic Search

The behaviour of a powder impacted on a target depends on its size, its particle size distribution (PSD), the material mechanical properties and the industrial rig. A methodology for the study of impact in an air jet mill allows one to evaluate the relation between the impact energy and the grindability of the impacted solids. Moreover, the behaviour of an

O Lecoq; P Guigon; M. N Pons

1999-01-01

420

Impact of hypertension on coronary artery spasm as assessed with intracoronary acetylcholine provocation test  

PubMed Central

Both hypertension and coronary artery spasm (CAS) are associated with endothelial dysfunction. Thus, a higher incidence of CAS is expected in hypertensive patients. We evaluated the impact of hypertension on CAS with intracoronary acetylcholine (ACh) provocation test. A total of 986 patients (685 hypertensive patients vs 301 normotensive patients) who underwent coronary angiography with ACh provocation test were enrolled. ACh was injected into the left coronary artery in incremental doses of 20, 50 and 100??g?min?1. Significant CAS was defined as a transient >70% luminal narrowing with concurrent chest pain and/or ST-segment changes. Although the incidences of significant ACh-induced CAS were similar between hypertensive and normotensive patients (35.8 vs 39.2%, P=0.303), multivariate logistic analysis showed that hypertension was negatively associated with ACh-induced CAS (odds ratio: 0.70, 95% confidence interval: 0.51–0.94, P=0.020). The angiographic characteristics of ACh-induced CAS were similar between these two groups. Subgroup analysis regarding the impact of the status of blood pressure control on CAS showed that hypertensive patients with controlled blood pressure had a significantly higher incidence of CAS than those with uncontrolled blood pressure (45.2 vs 27.9%, P<0.001), and that uncontrolled blood pressure was negatively associated with ACh-induced CAS (odds ratio: 0.56, 95% confidence interval: 0.40–0.79, P=0.001). In conclusion, despite the expected endothelial dysfunction, hypertension and uncontrolled blood pressure are negatively associated with CAS, suggesting that the mechanisms and risk factors of CAS may be significantly different from those of coronary artery disease.

Chen, K-Y; Rha, S-W; Li, Y-J; Poddar, K L; Jin, Z; Minami, Y; Saito, S; Park, J H; Na, J O; Choi, C U; Lim, H E; Kim, J W; Kim, E J; Park, C G; Seo, H S; Oh, D J

2010-01-01

421

Chicxulub: testing for post-impact hydrothermal inputs into the Tertiary ocean  

NASA Astrophysics Data System (ADS)

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 may undergo venting into the water column. A large proportion of the metals in such vent fluids precipitate close to the site of discharge; however, a proportion of the fluid is dispersed as a hydrothermal plume. Dissolved and particulate materials (in particular manganese and iron oxyhydroxides) can be carried for several hundreds of kilometers, before falling out to form metal-rich sediments. A series of Tertiary core samples has been obtained from the International Continental Drilling Program at Chicxulub (CSDP). These comprise fine-grained cream coloured carbonate sediments with fine laminations. Transmitted light and cathodoluminescence petrography have been used to carry out a preliminary characterization of the samples. Multi-element analysis has also been undertaken by ICP-AES. Samples were reduced to powder and digested using a nitric-perchloric-hydrofluoric acid attack. Rare earth elements (REE) have been analysed by ICP-MS and solutions were prepared using a modified nitric-perchloric-hydrofluoric acid attack. Geochemical analyses have been carried out to test for characteristic signals of hydrothermal input, such as enrichments in Mn, Fe, Cu, Zn, Pb, Mg, Ba, Co, Cr and Ni. The REE are scavenged from seawater onto iron oxide surfaces in the plume; hence anomalous REE concentrations are also indicative of hydrothermal addition. Furthermore, the type of anomaly can differentiate between sediments proximal (+ve Eu) distal (-ve Ce) to the vent site. The stratigraphic extent of any anomalies can be used to constrain the duration of any post-impact circulation. The wider significance of such hydrothermal circulation, if identified, include the potential formation of hydrothermal mineralization and vent-related ecosystems in the Chicxulub crater. The results will also have implications for the exploration of impact-related hydrothermal ecosystems on other planets.

Rowe, A.; Wilkinson, J.; Morgan, J.

2003-04-01

422

Instrumented impact testing of fabric-reinforced composite materials. Research and development report  

SciTech Connect

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.

Juska, T.D.; Crane, R.M.; Mixon, T.

1989-05-01

423

Cause of high variability in drug dissolution testing and its impact on setting tolerances.  

PubMed

Considering a variable mixing/stirring and flow pattern in a drug dissolution vessel as a likely source of high variability in results, experiments were conducted using USP paddle apparatus by placing (aligned to the walls) a metal strip (1.7 mm thickx6.4 mm wide) in a dissolution vessel. The metal strip forces the undisintegrated tablet to settle about 3 mm away from the centre, facilitates spread of disintegrated material and diminishes the cone formation at the bottom of the vessel. To assess the impact of this altered environment in the vessel, but still maintaining the vessel dimensions within required specifications, drug release characteristics were evaluated for products having different formulation/manufacturing attributes. Tests were conducted with calibrator tablets (USP prednisone and salicylic acid tablets and FDA proposed NCDA No. 2 prednisone tablets) and two commercially available products (250 mg amoxicillin capsules and 5 mg glibenclamide tablets). Except for the glibenclamide tablet product, all products gave significantly (P<0.01) higher dissolution results with vessels containing metal strip than without. The extent of increased dissolution with the metal strip varied from product to product i.e. USP prednisone tablet was the smallest (14.4%) and NCDA No. 2 was the largest (88.4%). Based on the results obtained from this study, it is concluded that employing the current apparatuses, in many cases products will provide lower than anticipated results which may not be reflective of the product drug release characteristics. Test-to-test variability, within or between laboratories, can also be very high depending on the settling position of the product once dropped in the vessel and/or due to slight aberration in the walls of the vessel by altering the extent of spread of disintegrated material at the bottom of the vessel. Thus, dissolution testing will require wider tolerances to be useful for comparison of batch-to-batch or interlaboratory results. PMID:11113646

Qureshi, S A; Shabnam, J

2001-01-01

424

Comparing Learning Style to Performance in On-Line Teaching: Impact of Proctored v. Un-Proctored Testing  

Microsoft Academic Search

The purpose of this study was to examine the impact that proctored versus un-proctored testing would have on learning for an on-line content module; and examine the relationship between LASSI variables and learning. A randomized, pre-test\\/post-test control group design was employed. College students in a pharmacy curriculum, were randomized to two groups utilizing asynchronous, on-line content with a medical terminology

Gregory S. Wellman

2005-01-01

425

Perceptions and Experiences of Random Breath Testing in Queensland and the Self-Reported Deterrent Impact on Drunk Driving  

Microsoft Academic Search

Objective. The present study explored the impact of random breath testing (RBT) on the attitudes, perceptions, and self-reported behavior of motorists in the Australian state of Queensland. Particular attention was given to how exposure to RBT impacted motorists' perceived risk of apprehension and self-reported behavior, relative to other variables of interest such as alcohol consumption.Methods. The study involved a telephone

Barry Watson; James Freeman

2007-01-01

426

Impact Test of Compact Vehicle with Modified Side Structure 35 mph, 60 degree Impact, Impala-to-Volare, Test No. 10.  

National Technical Information Service (NTIS)

Test no. 10 of 11 tests was conducted to investigate and improve crashworthiness of compact vehicle side structures. This test was run at 35 mph at a striking angle of 60 degrees. A 1978 Chevrolet Impala was the bullet vehicle and a modified 1976 Plymouth...

E. Enserink

1977-01-01

427

Impact Test of Compact Vehicle with Modified Side Structure, 35 mph, 90 degree Impact, Impala-to-Volare, Test No. 11.  

National Technical Information Service (NTIS)

Test no. 11 of 11 tests was conducted to investigate and improve crashworthiness of compact vehicle side structures. This test was run at 35 mph at a striking angle of 90 degrees. A 1978 Chevrolet Impala was the bullet vehicle and a modified 1976 Plymouth...

E. Enserink

1979-01-01

428

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

SciTech Connect

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.

Yokoyama, T. (Osaka Univ. (Japan). Faculty of Engineering Okayama Univ. of Science (Japan). Dept. of Mechanical Engineering)

1993-11-01

429

Impacts of transportation on a test and evaluation facility for nuclear waste disposal: a systems analysis  

SciTech Connect

An essential element of the Test and Evaluation Facility (TEF) is a waste packaging facility capable of producing a small number Test and Evaluation Facility of packages consisting of several different waste forms. The study envisions three scenarios for such a packaging facility: (1) modify an existing hot cell facility such as the Engine Maintenance Assembly and Disassembly (EMAD) facility at the Nevada Test Site so that it can serve as a packaging facility for the TEF. This scenario is referred to as the EMAD Option. (2) Build a new generic packaging facility (GPF) at the site of the TEF. In other words, colocate the GPF and the TEF. This scenario is referred to as the GPF Option, and (3) utilize the EMAD facility in conjunction with a colocated GPF (of minimal size and scope) at the TEF. This scenario is referred to as the Split Option. The results of the system study clearly bring out the fact that transportation has a significant impact on the selection and siting of the waste packaging facility. Preliminary conclusions, subject to the assumptions of the study, include the following: (1) regardless of the waste form, the GPF option is preferable to the other two in minimizing both transportation costs and logistical problems, (2) for any given scenario and choice of waste forms, there exists a candidate TEF location for which the transportation costs are at a minimum compared to the other locations, (3) in spite of the increased transportation costs and logistical complexity, the study shows that the overall system costs favor modification of an existing hot cell facility for the particular case considered.

Varadarajan, R.V.; Peterson, R.W.; Joy, D.S.; Gibson, S.M.

1983-12-31

430

The Arctic as a test case for an assessment of climate impacts on national security.  

SciTech Connect

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.

Taylor, Mark A.; Zak, Bernard Daniel; Backus, George A.; Ivey, Mark D.; Boslough, Mark Bruce Elrick

2008-11-01

431

Supplemental Final Environmental Impact Statement for Advanced Solid Rocket Motor Testing at Stennis Space Center.  

National Technical Information Service (NTIS)

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 regard...

1990-01-01

432

Factors affecting the validity and accuracy of instrumented impact tests with special reference to the pendulum and drop-tower versions of the Charpy test  

SciTech Connect

While it is theoretically true that useful information can be calculated from recorded instrumented impact test data, such calculations can be performed only if the correct calibration procedures and numerical methods are used. However, neither the literature nor existing standards contain useful guidance with respect to correct calibration procedures or adequate numerical methods. Two different homogeneous populations of alloy 4340 steel Charpy bars were manufactured and tested by instrumented pendulum and drop tower versions of the Charpy impact tests. Data were recorded using the COMPUTERSCOPE system manufactured by RC Electronics. The two instrumented tups were calibrated by applying known loads statically, by matching energy results to known ASTM E-23 (Charpy impact test) results and by matching calculated general yield loads to assumed values of general yield loads. Using the calibration data, absorbed energies, general yield loads, and total system compliance were calculated from the recorded tup output information for both populations and test machines using ASTIR, a computer program specifically designed and constructed for this work.

Stevens, W.C.

1988-01-01

433

Impact testing and simulation of composite sandwich structures for civil transportation  

Microsoft Academic Search

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

L Torre; J. M Kenny

2000-01-01

434

Testing the origin of high remanent magnetization in Vredefort impact structure  

Microsoft Academic Search

Vredefort impact structure (2.0 Ga) in South Africa with diameter 250-300 km [1] is considered largest impact structure on Earth. Values of natural remanent magnetization (NRM) for the impactites and some Archean host rocks of Vredefort impact structure are elevated compared to the values for similar rock types found elsewhere and these also show random directions of remanent magnetization [2,

J. M. Salminen; L. J. Pesonen; K. Lahti; K. Kannus

2010-01-01

435

Development and validation of side-impact crash and sled testing finite-element models  

Microsoft Academic Search

Side-impact collisions are the second leading cause of death and injury in the traffic accidents after frontal crashes. Side-impact airbags, side door bars and other protection techniques have been developed to provide occupant protection. To confirm the effectiveness of protection equipment installed in vehicles, studying the degree of impact is fundamental to understand the effect of automobile collisions on the

Tso-Liang Teng; Kuan-Chun Chang; Chien-Hsun Wu

2007-01-01

436

Testing temperatures and deflection rates dependencies of hydrogen embrittlements on RAFs  

NASA Astrophysics Data System (ADS)

It is well known that diffusible hydrogen in steels causes the reduction of fracture strength of steels. The hydrogen is usually trapped by vacancies, dislocations, grain boundaries, precipitates, voids, etc. The trapped hydrogen is thermally released from the trap sites. Thermal desorption spectroscopic (TDS) method is able to investigate the hydrogen trapping states in a material. In this study, the hydrogen embrittlement of a reduced activation ferritic steels (RAFs), JLF-1, is studied using a hydrogen cathodic electrolytic charging method. The amount of charged hydrogen into material was between 0 and 3.63 mppm. The small punch (SP) test and 1.5 mm charpy V-notch (1.5 mm CVN) test focusing on the test temperature and deflection rate dependencies studied at the between 20 and -196 °C, and deflection rates at 1 m/s and 0.2 mm/min.

Sakamura, T.; Komazaki, S.; Kishimoto, H.; Kohno, Y.

2011-10-01

437

Using single-species toxicity tests, community-level responses, and toxicity identification evaluations to investigate effluent impacts  

SciTech Connect

Whole effluent toxicity (WET) tests are increasingly used to monitor compliance of consented discharges, but few studies have related toxicity measured using WET tests to receiving water impacts. Here the authors adopt a four-stage procedure to investigate the toxicity and biological impact of a point source discharge and to identify the major toxicants. In stage 1, standard WET tests were employed to determine the toxicity of the effluent. This was then followed by an assessment of receiving water toxicity using in situ deployment of indigenous (Gammarus pulex) and standard (Daphnia magna) test species. The third stage involved the use of biological survey techniques to assess the impact of the discharge on the structure and functioning of the benthic macroinvertebrate community. In stage 4, toxicity identification evaluations (TIE) were used to identify toxic components in the effluent. Receiving-water toxicity and ecological impact detected downstream of the discharge were consistent with the results of WET tests performed on the effluent. Downstream of the discharge, there was a reduction in D. magna survival, in G. pulex survival and feeding rate, in detritus processing, and in biotic indices based on macroinvertebrate community structure. The TIE studies suggested that chlorine was the principal toxicant in the effluent.

Maltby, L.; Clayton, S.A.; Yu, H.; McLoughlin, N.; Wood, R.M.; Yin, D.

2000-01-01

438

The effect of strong carbide-forming elements such as Mo, Ti, V and Nb on the microstructure of ferritic stainless steel  

Microsoft Academic Search

The effects of both stabilizing elements such as Mo, Ti, V and Nb and of homogenization on microstructure, thermal properties, and some mechanical properties of ferritic stainless steels containing 18 wt.% Cr were investigated using scanning electron microscopy, energy-dispersive spectrometry, X-ray diffraction, differential thermal analysis, microhardness measurements and Charpy V notch impact tests. These stabilizing elements formed hard MC carbides,

V Kuzucu; M Aksoy; M. H Korkut

1998-01-01

439

Damage evolution in GLARE fibre-metal laminate under repeated low-velocity impact tests  

NASA Astrophysics Data System (ADS)

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.

Morinière, Freddy D.; Alderliesten, René C.; Tooski, Mehdi Yarmohammad; Benedictus, Rinze

2012-12-01

440

Bethesda criteria for microsatellite instability testing: impact on the detection of new cases of Lynch syndrome.  

PubMed

In 1997 Bethesda Guidelines (BG) were established and in 2004 those criteria were revised (RBG), with the main goal of selecting colorectal cancers (CRC) that should be subjected to microsatellite instability (MSI) testing. High microsatellite instability (MSI-H) is an intermediate marker for mutational analysis of the mismatch repair (MMR) genes involved in the genesis of Lynch Syndrome (LS). We aimed to evaluate and compare BG/RBG in the detection of MSI-H and subsequent identification of pathogenic MMR genes mutations. We included 174 patients with CRC and indication for MSI analysis according to BG or RBG. MSI testing was performed with the Bethesda markers and mutational analysis of MLH1, MSH2 and MSH6 genes undertaken with DGGE, MLPA and direct sequencing. One hundred fourteen of 174 patients (65.5 %) fulfilled BG and all of them RBG. With the BG, MSI-H was detected in 37/114 (32.5 %) CRCs and mutational analysis was positive in 14/37 (37.8 %) patients. The RBG led to detection of MSI-H in 49/174 (28.2 %) of the CRCs, having the mutational analysis been positive in 16/49 (32.7 %) patients. We could identify 14/114 (12.3 %) new cases of LS, through BG and 16/174 (9.2 %) via RBG. BG presented a similar overall percentage for the detection of MSI-H and mutations when compared with RBG. RBG implicated the analysis of more patients, though they gave rise to detection of two additional LS cases. This difference has a significant impact on the establishment of preventive measures, mainly for CRC, in all the mutation-carriers belonging to these families. PMID:22776989

Serrano, Miguel; Lage, Pedro; Belga, Sara; Filipe, Bruno; Francisco, Inês; Rodrigues, Paula; Fonseca, Ricardo; Chaves, Paula; Claro, Isabel; Albuquerque, Cristina; Pereira, António Dias

2012-12-01

441

Pressure-based abdominal injury criteria using isolated liver and full-body post-mortem human subject impact tests.  

PubMed

Liver trauma research suggests that rapidly increasing internal pressure plays a role in liver injury. Previous work has shown a correlation between pressure and liver injury in pressurized ex vivo human livers when subjected to blunt impacts. The purpose of this study was to extend the investigation of this relationship between pressure and liver injury by testing full-body post-mortem human surrogates (PMHS). Pressure-related variables were compared with one another and also to previously proposed biomechanical predictors of abdominal injury. Ten PMHS were tested. The abdominal vessels were pressurized to physiological levels using saline, and a pneumatic ram impacted the right side of the specimen ribcage at a nominal velocity of 7.0 m/s. Specimens were subjected to either lateral (n = 5) or oblique (n = 5) impacts, and the impact- induced pressures were measured by transducers inserted into the hepatic veins and inferior vena cava. The liver injuries observed were similar to those documented in the Crash Injury Research Engineering Network (CIREN) trauma database. Using binary logistic regression to develop injury risk functions, it was determined the peak rate of pressure change (?max) was a statistically significant predictor of AIS ? 3 liver injury for both the PMHS and ex vivo testing. This suggests that ?max is a good predictor of liver injury regardless of the impact boundary conditions. PMID:22869313

Kremer, Matthew A; Gustafson, Hannah M; Bolte, John H; Stammen, Jason; Donnelly, Bruce; Herriott, Rodney

2011-11-01

442

The impact of letter spacing on reading: a test of the bigram coding hypothesis.  

PubMed

Identifying letters and their relative positions is the basis of reading in literate adults. The Local Combinations Detector model hypothesizes that this ability results from the general organization of the visual system, whereby object encoding proceeds through a hierarchy of neural detectors that, in the case of reading, would be tuned to letters, bigrams, or other letter combinations. Given the increase of receptive fields by a factor of 2 to 3 from one neural level to the next, detectors should integrate information only for letters separated by at most 2 other characters. We test this prediction by measuring the impact of letter spacing on reading, purifying this effect from confounding variables. We establish that performance deteriorates non-linearly whenever letters are separated by at least 2 blank spaces, with the concomitant emergence of a word length effect. We then show that this cannot be reduced to an effect of physical size nor of visual eccentricity. Finally, we demonstrate that the threshold of about 2 spaces is constant across variations in font size. Those results support the hypothesis that the fast recognition of combinations of nearby letters plays a central role in the coding of words, such that interfering with this representation prevents the parallel analysis of letter strings. PMID:21566152

Vinckier, Fabien; Qiao, Emilie; Pallier, Christophe; Dehaene, Stanislas; Cohen, Laurent

2011-05-12

443

Dual axis radiographic hydrodynamic test facility. Final environmental impact statement, Volume 2: Public comments and responses  

SciTech Connect

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.

NONE

1995-08-01

444

Using item response theory to calibrate the Headache Impact Test (HIT™) to the metric of traditional headache scales  

Microsoft Academic Search

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

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

2003-01-01

445

Micro-impact test on lead-free BGA balls on Au\\/electrolytic Ni\\/Cu bond pad  

Microsoft Academic Search

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

Shengquan Ou; Yuhuan Xu; K. N. Tu; M. O. Alam; Y. C. Chan

2005-01-01

446

The impact of the Florida state-mandated Basic Skills Exit Tests at Miami-Dade Community College  

Microsoft Academic Search

The purpose of this study was to explore the impact of the Florida State-mandated Basic Skills Exit Tests (BSET) on the effectiveness of remedial instruction programs to adequately serve the academically underprepared student population. The primary research question concerned whether the introduction of the BSET has resulted in remedial completers who are better prepared for college-level coursework. ^ This study

Joanne Bashford

2002-01-01

447

Deformation mechanism at impact test of Al11% Si alloy processed by equal-channel angular pressing with rotary die  

Microsoft Academic Search

Al-11%Si (mass fraction) alloy was transformed into a ductile material by equal-channel angular pressing (ECAP) with a rotary die. Two mechanisms at impact test, slip deformation by dislocation motion and grain boundary sliding, were discussed. The ultrafine grains with modified grain boundaries and the high content of fine particles (

Ai-bin MA; Y. NISHIDA; Jing-hua JIANG; N. SAITO; I. SHIGEMATSU; A. WATAZU

2007-01-01

448

An experimental and modeling study of the thermomechanical behavior of an ABS polymer structural component during an impact test  

Microsoft Academic Search

An experimental and modeling study of the thermomechanical behavior of an ABS polymer structural component during an impact test is presented. The structural component was a heel of a woman's shoe made of ABS polymer material reinforced or not by a pin. Kinematics and thermal full field measurement techniques were used to observe the material and structural component during preliminary

H. Louche; F. Piette-Coudol; R. Arrieux; J. Issartel

2009-01-01

449

Microbial Rock Inhabitants Survive Hypervelocity Impacts on Mars-Like Host Planets: First Phase of Lithopanspermia Experimentally Tested  

Microsoft Academic Search

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

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

450

Testing the Impact of Job-Related Variables on a Utility Judgment Training Criterion beyond Background and Affective Reaction Variables  

ERIC Educational Resources Information Center

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…

Blau, Gary; Gibson, Greg; Bentley, Melissa; Chapman, Susan

2012-01-01

451

The affective and motivational impact of the test accommodation extended time based on students' performance goal orientations  

Microsoft Academic Search

This study examined whether differences in performance goal orientation impacted learning disabled students positive emotional responses, negative emotional responses, and ratings of self-efficacy toward an academic task when provided with the test accommodation extended time. Ninety high school students participated in the study and through the use of median split analyses individuals were successfully classified, as either high or low,

Joshua Paul Logan

2009-01-01

452

The Impact of BIB Spiraling-Induced Missing Data Patterns on Goodness-of-Fit Tests in Factor Analysis.  

ERIC Educational Resources Information Center

|This article considers the impact of missing data arising from balanced incomplete block (BIB) spiraled designs on the chi-square goodness-of-fit test in factor analysis. The new approach is shown to outperform the pairwise available case method for continuous variables and to be comparatively better for dichotomous variables. (SLD)|

Kaplan, David

1995-01-01

453

Science course sequences: The alignment of written, enacted, and tested curricula and their impact on grade 11 HSPA science scores  

Microsoft Academic Search

The purpose of this mixed method study was to examine the alignment of the written, enacted, and tested curricula of the Ocean City High School science course sequencing and its impact on student achievement. This study also examined the school's ability to predict student scores on the science portion of the High School Proficiency Assessment (HSPA). Data collected for science

Christine A. Lentz

2007-01-01

454

Aluminium foams as a filler for leading edges: Improvements in the mechanical behaviour under bird strike impact tests  

Microsoft Academic Search

The use of aluminium foams as filler materials in aeronautical leading edges is investigated. Particularly, the improvement of the mechanical behaviour of the filled structure respect to the hollow one is analysed by means of standard bird strike impact tests. For this purpose, a collection of AlSi10 foams were fabricated using the powder metallurgical route (PM), and introduced into leading

J. A. Reglero; M. A. Rodríguez-Pérez; E. Solórzano; J. A. de Saja

2011-01-01

455

Impact of Two Social-Cognitive Interventions to Prevent Adolescent Substance Use: Test of an Amenability to Treatment Model.  

ERIC Educational Resources Information Center

|Tests the impact of two social-cognitive interventions implemented in the 6th grade (Intervention 1) and 8th/9th grades (Intervention 2) on student's skill acquisition and on their 9th and 10th grade substance use. Results indicate positive program effects for Intervention 2 on skill acquisition and overall drug involvement. (RJM)|

Snow, David L.; Tebes, Jacob Kraemer; Ayers, Tim S.

1997-01-01

456

TESTING THE LEAPFROG HYPOTHESIS: The impact of existing infrastructure and telecommunications policy on the global digital divide  

Microsoft Academic Search

This paper tests the ‘leap-frog’ hypothesis by modeling the impact of existing telecommunications infrastructure, controlling for economic, political and demographic factors, on changes in information communication technology (ICT) access for over 200 countries between 1995 and 2005. This study has significantly greater coverage than previous research, in terms of both time frame and country cases. First, the analysis demonstrates that

Philip N. Howard

2007-01-01

457

Drop tests and numerical impact analyses of new cask designs for High Activity Waste (Haw) and spent fuel - updated BAM design testing experiences  

SciTech Connect

In Germany, several new cask designs by international vendors (Gesellschaft fuer Nuklear Service mbH (GNS), TN International (TNI), Mitsubishi Heavy Industries (MHI)) are under design testing and within official licensing procedures for transport and storage casks for spent fuel and high activity waste (HAW). BAM (the German Federal Institute for Materials Research and Testing) has been performing several extensive drop test series with prototype casks to evaluate the safety margins against mechanical test conditions. An important project is the new GNS cask design for HAW, the CASTOR{sup R} HAW 28M. Sixteen drop tests have been performed under transport conditions with a 1:2 scale cask model equipped with impact limiters and extensively instrumented with strain gauges and accelerometers. Additionally, the accident scenario inside a storage facility has been investigated by a cask drop without impact limiters onto a nearly unyielding target. This scenario is dominated by highly dynamic effects and interactions between the test object and the target. Complete safety assessments for such mechanical accident scenarios and highly loaded cask structures require additional numerical investigations. They are done by complex finite element (FE) calculations that provide detailed dynamic stress and strain analyses all over the cask structure and at such points where sensors can't be applied. In addition, differences between the material property quantities of the prototype cask and the minimum material property requirements for the cask series production can be investigated as well as dimensional tolerances. By example, the safety assessment method and some of its special aspects are illustrated by the cask drop without an impact limiter onto a hard foundation. The main aspects and challenges are to develop a sufficient computer model of the cask and foundation and to provide detailed interpretation of the large amount of measurement data for achieving good correlation between experimental and numerical results. (authors)

Volzke, H.; Zencker, U.; Qiao, L.; Feutlinske, K.; Musolff, A. [Bundesanstalt fur Materialforschung und -prufung (BAM), Berlin (Germany)

2007-07-01

458

Board Level Dynamic Response and Solder Ball Joint Reliability Analysis under Drop Impact Test with Various Impact Orientations  

Microsoft Academic Search

Portable electronics, such as notebooks, cameras and cell phones, can be easily dropped by our miss handling. To mimic the real dropping, drop tests are usually used to study the dynamic response of Printed Circuit Board (PCB) as well as the reliability of the solder ball joints in laboratory. The reliability of solder ball joints is a critical issue since

Z. J. Xu; T. X. Yu

2008-01-01

459

The Impact of the Feminist Critique on Tests, Assessment, and Methodology.  

ERIC Educational Resources Information Center

|Discusses early feminist efforts in psychological assessment, and reviews general issues related to feminist methodology. Successful impact and lack of impact of feminist criticism are illustrated by the revisions of the Strong Campbell Interest Inventory and the Minnesota Multiphasic Personality Inventory (1990), respectively. (SLD)|

Lewin, Miriam; Wild, Cheryl L.

1991-01-01

460

A comparison of hydrodynamic impacts prediction methods with two dimensional drop test data  

Microsoft Academic Search

The effect of hydrodynamic impacts on a ship's bow structure is an important design consideration. In addition, to possible failure to local structure, such impacts can generate slam-induced whipping loads, the magnitude of which when combined with ordinary wave induced loads, could lead to first passage failure of a ship's hull girder. This paper presents the results of a recent

Allen Engle; Richard Lewis

2003-01-01

461

Design and sled testing of a high back booster seat prototype offering improved side impact protection  

Microsoft Academic Search

Current booster seats do not offer effective protection in side impact. Previous studies have suggested that the level of protection provided by boosters in side impact can be substantially improved through relatively minor design changes to booster seat geometry. Previous studies have also shown that booster seat performance can be significantly enhanced by rigidly anchoring booster seats to the vehicle

M. Huot; J. Brown; L. E. Bilston

2005-01-01

462

Examinations and Testing the Impacts of Quality of Work Life on Productivity  

Microsoft Academic Search

The research attempts to examine whether there is possible impact from quality of work life (hereafter known as QWL) on productivity. Sink and Tuttle (1989) hypothesize the interrelationships among the seven key performance criteria, i.e., profitability, productivity, innovation, QWL, quality, effectiveness, and efficiency. In these proposed interrelationships, the level of productivity is either influenced or impacted by any change in

Kanokwan Kingpadung; Kongkiti Phusavat

463

Impacts of diurnal temperature range on ecosystem carbon balance: an experimental test in grassland mesocosms  

NASA Astrophysics Data System (ADS)

Although extensive research has determined ecosystem responses to equal increases in day and night temperatures, current temperature increases have generally been asymmetrical, with increases in minimum temperature (Tmin) exceeding increases in maximum temperature (Tmax), or vice versa, depending on location. We conducted an ecosystem warming experiment in a perennial grassland to determine the effects of asymmetrically elevated diel temperature profiles using precision climate-controlled sunlit environmental chambers. Asymmetrically warmed chambers (+5/+2°C, Tmin/Tmax) were compared with symmetrically warmed (+3.5°C continuously) and control chambers (ambient). We tested three alternative hypotheses comparing the carbon balance under symmetric (SYM) and asymmetric (ASYM) warming: H1) SYM < ASYM, due either to a shorter growing season in the SYM treatment from lower Tmin, or to higher respiratory costs from higher Tmax; H2) SYM > ASYM, because warmer nights in the ASYM treatment increase respiration more then photosynthesis, reducing plant growth; H3) SYM = ASYM, due to a combination of effects. Results from the third growing season support H3, that carbon balance is the same under the two elevated diel temperature profiles. During the early part of the growing season, asymmetric warming resulted in higher nighttime respiratory losses than symmetric warming, but these greater loses were compensated by increased early morning photosynthesis. As a result, carbon balance was not different in the two warming treatments at daily time steps. Furthermore, declines in soil moisture over the growing season may have important modulating impacts on the temperature sensitivity of carbon fluxes. As soils dried, carbon fluxes became less sensitive to diel temperature fluctuations, and more similar in the symmetric and asymmetric treatments.

Phillips, C. L.; Gregg, J. W.; Wilson, J. K.; Pangle, L. A.; Bailey, D.

2009-12-01

464

Effect of porcelain shape for strain behavior of strengthened porcelain in impact test  

NASA Astrophysics Data System (ADS)

Four types of strengthened porcelains were evaluated by an impact examination machine based on ASTM C368-88. The waveform of strain developed on impact was measured by a strain gauge pasted on the inside surface and the outside surface, vertical and horizontal direction of porcelain. In minute scales, procelain deformed into an oval shape as a whole by an impact onto the rim, where the higher tensile strain occurred in the horizontal direction on the inside surface of porcelain. The maximum tensile strain occurred at the impact point. The waveform of strain, that showed two remarkable peaks, was greatly affected by porcelain shape. In addition it was more or less affected by measurement conditions such as impact energy, weight or speed of hammer, weight for holding, and position of backstops.

Hayashi, Akemi; Kurachi, Kazumasa; Mizuno, Masatoshi; Ota, Toshitaka

2011-10-01

465

Side Impact Protection in Production Vehicles MDB-to-Car Side Impact Test of a 26 deg Crabbed Moving Deformable Barrier to a 1988 Hyundai Excel GL 4-Door Sedan at 33.5 MPH.  

National Technical Information Service (NTIS)

A 30/15 mph 90 degree Impact (Moving Deformable Barrier(MDB)) test was performed at the Advanced Technology Center Crash Test Facility in New York in December 1988. The impact velocity of the MDB was 33.9 mph, and the ambient temperature at the struck sid...

D. J. Travale W. E. Levan

1988-01-01

466

Investigation on occupant ejection in high severity rear impact based on post mortem human subject sled tests.  

PubMed

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

Petit, Philippe; Luet, Carole; Potier, Pascal; Vallancien, Guy

2011-11-01

467

High-silicon {sup 238}PuO{sub 2} fuel characterization study: Half module impact tests  

SciTech Connect

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. The modular GPHS design was developed to address both survivability during launch abort and return from orbit. Previous testing conducted in support of the Galileo and Ulysses missions documented the response of GPHSs to a variety of fragment-impact, aging, atmospheric reentry, and Earth-impact conditions. The evaluations documented in this report are part of an ongoing program to determine the effect of fuel impurities on the response of the heat source to conditions baselined during the Galileo/Ulysses test program. In the first two tests in this series, encapsulated GPHS fuel pellets containing high levels of silicon were aged, loaded into GPHS module halves, and impacted against steel plates. The results show no significant differences between the response of these capsules and the behavior of relatively low-silicon fuel pellets tested previously. {copyright} {ital 1997 American Institute of Physics.}

Reimus, M.A. [Los Alamos National Laboratory Nuclear Material Technology Division P.O. Box 1663, MS-E502 Los Alamos, New Mexico87545 (United States)

1997-01-01

468

Evaluation of a new battery of toxicity tests for boreal forest soils: assessment of the impact of hydrocarbons and salts.  

PubMed

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

Princz, Juliska I; Moody, Mary; Fraser, Christopher; Van der Vliet, Leana; Lemieux, Heather; Scroggins, Rick; Siciliano, Steven D

2012-02-24

469

Vehicle Impact Tests on Frangible and Yielding Post Designs of Bridge Parapets.  

National Technical Information Service (NTIS)

Two designs of post and rail bridge parapets were developed which provide more positive containment of vehicles and better vehicle response after impact than conventional parapets. In one design the posts fracture at their bases at a predetermined transve...

V. J. Jehu

1972-01-01

470

Testing and multi-scale modeling of drop and impact loading of complex MEMS microphone assemblies  

Microsoft Academic Search

Failure under dynamic mechanical stresses caused by impact and drop loading is a critical concern for reliability of surface mount components in portable electronic products. This study focuses on drop-induced failures in system-in-package (SIP) COTS Micro-Electro-Mechanical Systems (MEMS) components that are mounted on PWAs. In particular, we are interested in the effects of secondary impacts that can occur between the

J. Meng; T. Mattila; A. Dasgupta; M. Sillanpaa; R. Jaakkola; K. Andersson; E. Hussa

2012-01-01

471

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

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

P. R. Davis; W. C. Walton

1982-01-01

472

Effect of impact pulse parameters on consistency of board level drop test and dynamic responses  

Microsoft Academic Search

Board level solder joint reliability performance during drop test is a critical concern to semiconductor and electronic product manufacturers. JEDEC standard for board level drop test of handheld electronic products addresses requirements from test board design, material, construction and assembly of test board, component location, tester setup, and reporting format in details. However, the effects of peak acceleration, duration, and

Jing-en Luan; Tong Yan Tee

2005-01-01

473

Cadmium Depletion Impacts on Hardening Neutron6 Spectrum for Advanced Fuel Testing in ATR  

Microsoft Academic Search

For transmuting long-lived isotopes contained in spent nuclear fuel into shorter-lived fission products effectively is in a fast neutron spectrum reactor. In the absence of a fast spectrum test reactor in the United States of America (USA), initial irradiation testing of candidate fuels can be performed in a thermal test reactor that has been modified to produce a test region

Gray S. Chang

2011-01-01

474

Assessment of impact damage in Kevlar{reg_sign}-epoxy, filament-wound spherical test specimens by acoustic emission techniques  

SciTech Connect

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.

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

475

Beta-Testing the “Particular Machine”: The Machine-or-Transformation Test in Peril and Its Impact on Cloud Computing  

Microsoft Academic Search

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.

Richard M. Lee

2012-01-01

476

Application of nondestructive testing methods to study the damage zone underneath impact craters of MEMIN laboratory experiments  

NASA Astrophysics Data System (ADS)

Within the framework of the Multidisciplinary Experimental and Modeling Impact Research Network (MEMIN) research group, the damage zones underneath two experimentally produced impact craters in sandstone targets were investigated using several nondestructive testing (NDT) methods. The 20 × 20 × 20 cm sandstones were impacted by steel projectiles with a radius of 1.25 mm at approximately 5 km s-1, resulting in craters with approximately 6 cm diameter and approximately 1 cm depth. Ultrasound (US) tomography and vibrational analysis were applied before and after the impact experiments to characterize the damage zone, and micro-computer tomography (?-CT) measurements were performed to visualize subsurface fractures. The newly obtained experimental data can help to quantify the extent of the damage zone, which extends to about 8 cm depth in the target. The impacted sandstone shows a local p-wave reduction of 18% below the crater floor, and a general reduction in elastic moduli by between approximately 9 and approximately 18%, depending on the type of elastic modulus. The results contribute to a better empirical and theoretical understanding of hypervelocity events and simulations of cratering processes.

Moser, Dorothee; Poelchau, Michael H.; Stark, Florian; Grosse, Christian

2013-01-01

477

General-purpose heat source: Research and development program, radioisotope thermoelectric generator/thin fragment impact test  

SciTech Connect

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.

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