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1

The V-Notched Rail Shear Test  

Microsoft Academic Search

A V-notched rail shear test has been developed for measuring the shear modulus and shear strength of composites and other materials. This test method, standardized as ASTM D 7078, incorporates attractive features of the existing Iosipescu and two-rail shear tests. The V-notched rail shear specimen provides a larger gage section than the standard Iosipescu shear specimen and provides enhanced loading

Daniel O. Adams; Joseph M. Moriarty; Adam M. Gallegos; Donald F. Adams

2007-01-01

2

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

NASA Technical Reports Server (NTRS)

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

Hill, Charles S.; Oliveras, Ovidio M.

2011-01-01

3

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

4

Instrumented impact testing machine with reduced specimen oscillation effects  

NASA Astrophysics Data System (ADS)

A pendulum-type instrumented Charpy test apparatus based on inverted test geometry was developed. Geometry inversion reduces inertia load and specimen oscillation effects. Initial impact energy is double that of standard (300 J) impact testers, allowing the use of larger (10 x 20 x 110 mm) bend specimens than normal Charpy specimens. The rotation axis in the three point bending is nearly stationary, making COD-measurements possible. Inertia effects and specimen oscillations are compared with the conventional tester, and using an analytical finite element model for Charpy V-notch specimens. Better performance for the inverted geometry is reported.

Rintamaa, R.; Ranka, K.; Wallin, K.; Ikonen, K.; Talja, H.; Kotilainen, H.; Sirkkola, E.

1984-07-01

5

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...

6

Charpy impact energy, fracture toughness and ductile–brittle transition temperature of dual-phase 590 Steel  

Microsoft Academic Search

Advanced high strength steels (AHSS) have been introduced and gradually adopted in vehicle structures as lightweight materials in the past years. Engineering performance of AHSS in many areas have shown that they are superior to the conventional steels. In this paper, we present the results from Charpy V-Notch impact tests on dual phase 590 (DP590) steel, which belongs to the

Y. J. Chao; J WARDJR; R. G. Sands

2007-01-01

7

Impact Tests for Woods  

NASA Technical Reports Server (NTRS)

Although it is well known that the strength of wood depends greatly upon the time the wood is under the load, little consideration has been given to this fact in testing materials for airplanes. Here, results are given of impact tests on clear, straight grained spruce. Transverse tests were conducted for comparison. Both Izod and Charpy impact tests were conducted. Results are given primarily in tabular and graphical form.

1922-01-01

8

Evaluation of Impact Properties to Forged 3CR Steel by Barkhausen Noise  

NASA Astrophysics Data System (ADS)

This paper reports that the Barkhausen noise method can be used to accurately characterize forged reactor vessels. The Charpy V-notch impact tests were conducted on the respective specimens with three different types of heat history. Various test results including fracture appearance transition temperature (FATT) were obtained. The Barkhausen noise voltage changed with heat treatment temperature (870 1000°C) and conditions (Tempered, PWHT). The fracture appearance transition temperature can be predicted using the Barkhausen noise voltage.

Baek, Un Bong; Lee, Seok Cheol; Nahm, Seung Hoon; Nam, Young Hyun

9

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

10

Influence of phase transformations on the asymptotic residual stress distribution arising near a sharp V-notch tip  

NASA Astrophysics Data System (ADS)

In this work, the residual stress distribution induced by the solidification and cooling of a fusion zone in the vicinity of a sharp V-notch tip is investigated. The intensity of the residual asymptotic stress fields, quantified by the notch stress intensity factors, was studied for two different V-notch specimen geometries under generalized plane-strain conditions. In order to analyze the influence of phase transformations on the obtained results, simulations with and without the effects of phase transformation were carried out on ASTM SA 516 steel plates. Thanks to the possibilities of numerical modelling, additional analyses were performed without taking into account the transformation plasticity phenomenon. It was found that phase transformation effects (both volume change and transformation plasticity) have a great influence on the intensity and sign of the asymptotic stress fields at the sharp V-notch tips. This result is believed to be very important for the correct numerical determination (and future applications) of notch stress intensity factors resulting from asymptotic residual stress distributions induced by transient thermal loads. The analyses were performed with the finite element code SYSWELD.

Ferro, P.

2012-12-01

11

Low temperature impact testing of welded structural wrought iron  

NASA Astrophysics Data System (ADS)

During the second half of the 19th century, structural wrought iron was commonly used in construction of bridges and other structures. Today, these remaining structures are still actively in use and may fall under the protection of historic preservation agencies. Continued use and protection leads to the need for inspection, maintenance, and repair of the wrought iron within these structures. Welding can be useful to achieve the appropriate repair, rehabilitation, or replacement of wrought iron members. There is currently very little published on modern welding techniques for historic wrought iron. There is also no pre-qualified method for this welding. The demand for welding in the repair of historic structural wrought iron has led to a line of research investigating shielded metal arc welding (SMAW) of historic wrought iron at the University of Colorado Denver. This prior research selected the weld type and other weld specifications to try and achieve a recognized specific welding procedure using modern SMAW technology and techniques. This thesis continues investigating SMAW of historic wrought iron. Specifically, this thesis addresses the toughness of these welds from analysis of the data collected from performing Charpy V-Notch (CVN) Impact Tests. Temperature was varied to observe the material response of the welds at low temperature. The wrought iron used in testing was from a historic vehicle bridge in Minnesota, USA. This area, and many other areas with wrought iron structures, can experience sustained or fluctuating temperatures far below freezing. Investigating the toughness of welds in historic wrought iron at these temperatures is necessary to fully understand material responses of the existing structures in need of maintenance and repair. It was shown that welded wrought iron is tougher and more ductile than non-welded wrought iron. In regards to toughness, welding is an acceptable repair method. Information on wrought iron, low temperature failure, welding, and impact testing is also presented in an effort to provide those writing codes and standards, designing, or working with historic structural wrought iron more data, analysis, and research based recommendations.

Rogers, Zachary

12

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

13

High Pressure Quick Disconnect Particle Impact Tests  

NASA Technical Reports Server (NTRS)

NASA Johnson Space Center White Sands Test Facility (WSTF) performed particle impact testing to determine whether there is a particle impact ignition hazard in the quick disconnects (QDs) in the Environmental Control and Life Support System (ECLSS) on the International Space Station (ISS). Testing included standard supersonic and subsonic particle impact tests on 15-5 PH stainless steel, as well as tests performed on a QD simulator. This paper summarizes the particle impact tests completed at WSTF. Although there was an ignition in Test Series 4, it was determined the ignition was caused by the presence of a machining imperfection. The sum of all the test results indicates that there is no particle impact ignition hazard in the ISS ECLSS QDs. KEYWORDS: quick disconnect, high pressure, particle impact testing, stainless steel

Rosales, Keisa R.; Stoltzfus, Joel M.

2009-01-01

14

Solid rocket booster water impact test  

NASA Astrophysics Data System (ADS)

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

Bugg, F.

1982-03-01

15

Charpy Impact Verification We evaluate the performance of pendulum impact test  

E-print Network

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

Perkins, Richard A.

16

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

17

Tests of the Giant Impact Hypothesis  

NASA Technical Reports Server (NTRS)

The giant impact hypothesis has gained popularity as a means of explaining a volatile-depleted Moon that still has a chemical affinity to the Earth. As Taylor's Axiom decrees, the best models of lunar origin are testable, but this is difficult with the giant impact model. The energy associated with the impact would be sufficient to totally melt and partially vaporize the Earth. And this means that there should he no geological vestige of Barber times. Accordingly, it is important to devise tests that may be used to evaluate the giant impact hypothesis. Three such tests are discussed here. None of these is supportive of the giant impact model, but neither do they disprove it.

Jones, J. H.

1998-01-01

18

FOD impact testing of composite fan blades  

NASA Technical Reports Server (NTRS)

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

Johns, R. H.

1974-01-01

19

Impact testing on composite fan blades  

NASA Technical Reports Server (NTRS)

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

Johns, R. H.

1974-01-01

20

FOD impact testing of composite fan blades  

NASA Technical Reports Server (NTRS)

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

Johns, R. H.

1974-01-01

21

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

22

16 CFR 1203.11 - Marking the impact test line.  

Code of Federal Regulations, 2014 CFR

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

2014-01-01

23

The GISS sounding temperature impact test  

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

24

Measurement Techniques for Hypervelocity Impact Test Fragments  

NASA Technical Reports Server (NTRS)

The ability to classify the size and shape of individual orbital debris fragments provides a better understanding of the orbital debris environment as a whole. The characterization of breakup fragmentation debris has gradually evolved from a simplistic, spherical assumption towards that of describing debris in terms of size, material, and shape parameters. One of the goals of the NASA Orbital Debris Program Office is to develop high-accuracy techniques to measure these parameters and apply them to orbital debris observations. Measurement of the physical characteristics of debris resulting from groundbased, hypervelocity impact testing provides insight into the shapes and sizes of debris produced from potential impacts in orbit. Current techniques for measuring these ground-test fragments require determination of dimensions based upon visual judgment. This leads to reduced accuracy and provides little or no repeatability for the measurements. With the common goal of mitigating these error sources, allaying any misunderstandings, and moving forward in fragment shape determination, the NASA Orbital Debris Program Office recently began using a computerized measurement system. The goal of using these new techniques is to improve knowledge of the relation between commonly used dimensions and overall shape. The immediate objective is to scan a single fragment, measure its size and shape properties, and import the fragment into a program that renders a 3D model that adequately demonstrates how the object could appear in orbit. This information would then be used to aid optical methods in orbital debris shape determination. This paper provides a description of the measurement techniques used in this initiative and shows results of this work. The tradeoffs of the computerized methods are discussed, as well as the means of repeatability in the measurements of these fragments. This paper serves as a general description of methods for the measurement and shape analysis of orbital debris.

Hill, Nicole E.

2008-01-01

25

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

26

Advanced Crew Escape Suits (ACES): Particle Impact Test  

NASA Technical Reports Server (NTRS)

NASA Johnson Space Center (JSC) requested NASA JSC White Sands Test Facility to assist in determining the effects of impaired anodization on aluminum parts in advanced crew escape suits (ACES). Initial investigation indicated poor anodization could lead to an increased risk of particle impact ignition, and a lack of data was prevalent for particle impact of bare (unanodized) aluminum; therefore, particle impact tests were performed. A total of 179 subsonic and 60 supersonic tests were performed with no ignition of the aluminum targets. Based on the resulting test data, WSTF found no increased particle impact hazard was present in the ACES equipment.

Rosales, Keisa R.; Stoltzfus, Joel M.

2009-01-01

27

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

28

Rail-car impact tests with steel coil: car crush  

Microsoft Academic Search

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

Eloy Martinez; David Tyrell; John Zolock

2003-01-01

29

Impact Testing for Materials Science at NASA - MSFC  

NASA Technical Reports Server (NTRS)

The Impact Testing Facility (ITF) at NASA - Marshall Space Flight Center is host to different types of guns used to study the effects of high velocity impacts. The testing facility has been and continues to be utilized for all NASA missions where impact testing is essential. The Facility has also performed tests for the Department of Defense, other corporations, as well as universities across the nation. Current capabilities provided by Marshall include ballistic guns, light gas guns, exploding wire gun, and the Hydrometeor Impact Gun. A new plasma gun has also been developed which would be able to propel particles at velocities of 20km/s. This report includes some of the guns used for impact testing at NASA Marshall and their capabilities.

Sikapizye, Mitch

2010-01-01

30

Preparation of calibrated test packages for particle impact noise detection  

NASA Technical Reports Server (NTRS)

A standard calibration method for any particle impact noise detection (PIND) test system used to detect loose particles responsible for failures in hybrid circuits was developed along with a procedure for preparing PIND standard test devices. Hybrid packages were seeded with a single gold ball, hermetically sealed, leak tested, and PIND tested. Conclusions are presented.

1977-01-01

31

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

32

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

E-print Network

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

Rothermel, Gregg

33

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

E-print Network

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

Rothermel, Gregg

34

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

E-print Network

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

Rothermel, Gregg

35

Psychometric Impacts of Above-Level Testing  

E-print Network

Above-level testing is the practice administering a test level—of usually an academic achievement or aptitude test—to a gifted or high achieving child. This procedure is widely accepted in gifted education circles, on the basis of theoretical...

Warne, Russell Thomas

2012-07-16

36

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

37

Psychosocial impact of presymptomatic genetic testing for transthyretin amyloidotic polyneuropathy  

Microsoft Academic Search

Presymptomatic genetic testing of an untreatable disease raises clinical, ethical, legal and psychosocial questions. Investigations in specific disorders are needed to help in understanding the motivation for and the impact of genetic testing in the lives of persons at risk for these diseases. Here, we performed a longitudinal study to investigate the psychological consequences of presymptomatic genetic testing on people

Anita Graceffa; Massimo Russo; Gian Luca Vita; Antonio Toscano; Roberto Dattola; Corrado Messina; Giuseppe Vita; Anna Mazzeo

2009-01-01

38

Determining the Overall Impact of Interruptions during Online Testing  

ERIC Educational Resources Information Center

With an increase in the number of online tests, interruptions during testing due to unexpected technical issues seem unavoidable. For example, interruptions occurred during several recent state tests. When interruptions occur, it is important to determine the extent of their impact on the examinees' scores. There is a lack of research on this…

Sinharay, Sandip; Wan, Ping; Whitaker, Mike; Kim, Dong-In; Zhang, Litong; Choi, Seung W.

2014-01-01

39

Reconstituted Charpy impact specimens. Final report  

SciTech Connect

The arc stud welding process was used to produce new, full size Charpy V-notch impact specimens from halves of Charpy specimens which had been previously tested. The apparatus was developed such that it could be used not only for unirradiated specimens, but also so that it could be adapted for in-cell use to produce new reconstituted specimens of irradiated material. The materials studied are of interest in nuclear applications. They include A533B, A36, A516-80, submerged arc weld metal (A508 base metal), HY80, cast duplex stainless steel, irradiated A533B, and irradiated submerged arc weld metal (A508 base metal). Both unirradiated and irradiated specimens were successfully produced and subsequently impact tested. In general, there was excellent agreement when comparing the original curves to the subsequent curves generated with reconstituted specimens. This program has shown that the arc stud welding process is well suited for producing reconstituted specimens at a reasonable cost using either unirradiated or irradiated material.

Perrin, J.S.; Wullaert, R.A.; McConnell, P.; Server, W.L.; Fromm, E.O.

1982-12-01

40

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

41

Low power arcjet test facility impacts  

NASA Technical Reports Server (NTRS)

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

Morren, W. Earl; Lichon, Paul J.

1992-01-01

42

Low power arcjet test facility impacts  

NASA Astrophysics Data System (ADS)

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

Morren, W. Earl; Lichon, Paul J.

1992-09-01

43

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

44

Impact Testing of Orbiter Thermal Protection System Materials  

NASA Technical Reports Server (NTRS)

This viewgraph presentation reviews the impact testing of the materials used in designing the shuttle orbiter thermal protection system (TPS). Pursuant to the Columbia Accident Investigation Board recommendations a testing program of the TPS system was instituted. This involved using various types of impactors in different sizes shot from various sizes and strengths guns to impact the TPS tiles and the Leading Edge Structural Subsystem (LESS). The observed damage is shown, and the resultant lessons learned are reviewed.

Kerr, Justin

2006-01-01

45

Multidimensional Validation Impact Tests on PZT 95\\/5  

Microsoft Academic Search

A family of nonplanar impact tests has been conducted on the ferrelectric ceramic PZT 95\\/5 and alumina-loaded epoxy (ALOX) encapsulants, with the purpose of providing benchmarks for material models in the ALEGRA wavecode. Diagnostics used included line-imaging and multipoint VISAR (velocity interferometry). Results from four tests conducted with ALOX cylinders impacted by nonplanar copper projectiles were compared with ALEGRA simulations.

Michael D. Furnish; Joshua Robbins; Wayne M. Trott; Lalit C. Chhabildas; R. Jeffery Lawrence; Stephen T. Montgomery

2001-01-01

46

Full-scale impact tests on pipelines  

Microsoft Academic Search

There was a possibility that a new submarine pipeline under construction might accidentally fall on an existing pipeline in operation. Full-scale tests were carried out to study what would happen, and to reassure the operator that the existing line would not be ruptured. The tests dropped one length of a concrete-coated 508mm (20-in) pipe onto another, and the largest kinetic

Andrew Palmer; Martin Touhey; Si Holder; Murray Anderson; Stephen Booth

2006-01-01

47

Fixture For Compression-After-Impact Tests Of Thin Specimens  

NASA Technical Reports Server (NTRS)

Special fixture holds specimen of laminated composite material in 20-klb (89-kN) or larger load frame for compression-after-impact test. In preparation for test, specimen damaged by dropping weight on it at known kinetic energy. During test, specimen loaded in compression, and load measured, until specimen fails. Measurement data used to characterize compressive strength of specimen after impact important indicator of ability of structural components made of composite material to tolerate damage. Tests give more-realistic measures of tolerance to damage.

Nettles, Alan T.; Hodge, Andrew J.; Lance, David G.

1994-01-01

48

Impact of uncertainty on modeling and testing  

NASA Technical Reports Server (NTRS)

A thorough understanding of the uncertainties associated with the modeling and testing of the Space Shuttle Main Engine (SSME) Engine will greatly aid decisions concerning hardware performance and future development efforts. This report will describe the determination of the uncertainties in the modeling and testing of the Space Shuttle Main Engine test program at the Technology Test Bed facility at Marshall Space Flight Center. Section 2 will present a summary of the uncertainty analysis methodology used and discuss the specific applications to the TTB SSME test program. Section 3 will discuss the application of the uncertainty analysis to the test program and the results obtained. Section 4 presents the results of the analysis of the SSME modeling effort from an uncertainty analysis point of view. The appendices at the end of the report contain a significant amount of information relative to the analysis, including discussions of venturi flowmeter data reduction and uncertainty propagation, bias uncertainty documentations, technical papers published, the computer code generated to determine the venturi uncertainties, and the venturi data and results used in the analysis.

Coleman, Hugh W.; Brown, Kendall K.

1995-01-01

49

A Comparison of Quasi-Static Indentation Testing to Low Velocity Impact Testing  

NASA Technical Reports Server (NTRS)

The need for a static test method for modeling low-velocity foreign object impact events to composites would prove to be very beneficial to researchers since much more data can be obtained from a static test than from an impact test. In order to examine if this is feasible, a series of static indentation and low velocity impact tests were carried out and compared. Square specimens of many sizes and thickness were utilized to cover the array of types of low velocity impact events. Laminates with a n/4 stacking sequence were employed since this is by the most common type of engineering laminate. Three distinct flexural rigidities under two different boundary conditions were tested in order to obtain damage due to large deflections, contact stresses and both to examine if the static indentation-impact comparisons are valid under the spectrum of damage modes that can be experienced. Comparisons between static indentation and low velocity impact tests were based on the maximum applied transverse load. The dependent parameters examined included dent depth, back surface crack length, delamination area and to a limited extent, load-deflection behavior. Results showed that no distinct differences could be seen between the static indentation tests and the low velocity impact tests, indicating that static indentation can be used to represent a low velocity impact event.

Nettles, Alan T.; Douglas, Michael J.

2001-01-01

50

Selecting Erlang Test Cases Using Impact Analysis  

NASA Astrophysics Data System (ADS)

Refactoring is a commonly used technology in the software development and maintenance process. However refactorings preserve the original behaviour of the system, developers want to be convinced about that, thus they retest the software after some modifications. Software testing is said to be the most expensive part of the lifecycle of software systems. Therefore our research focuses on selecting test cases affected by refactorings and have to be retested after the transformation. We describe the used mechanism in case of a dynamically typed functional programming language, Erlang.

Bozó, István; Tóth, Melinda

2011-09-01

51

30 CFR 7.46 - Impact test.  

Code of Federal Regulations, 2011 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...

2011-07-01

52

30 CFR 7.46 - Impact test.  

Code of Federal Regulations, 2010 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...

2010-07-01

53

30 CFR 7.46 - Impact test.  

Code of Federal Regulations, 2014 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...

2014-07-01

54

30 CFR 7.46 - Impact test.  

Code of Federal Regulations, 2012 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...

2012-07-01

55

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

56

Impact Testing and Simulation of Composite Airframe Structures  

NASA Technical Reports Server (NTRS)

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

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

2014-01-01

57

Marshall Space Flight Center's Impact Testing Facility Capabilities  

NASA Technical Reports Server (NTRS)

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

Finchum, Andy; Hubbs, Whitney; Evans, Steve

2008-01-01

58

Factors Influencing The Oblique Impact Test of Motorcycle Helmets.  

PubMed

Abstract Purpose: Oblique impact test can provide important information regarding the level of protection of a helmet. Two factors that influence the results of oblique impact tests on motorcycle helmets are discussed in this work. The first factor is the angle of the anvil on which the helmet impacts. The second one is the friction between the headform and the helmet's interior. Methods: To study the first factor, two anvil angles are provided, one 30(º) and the other one 15(º) to the vertical. To analyze the second factor, we consider two types of headform surfaces: the original metal surface of the standard headform, and the same headform covered uniformly with a layer of silicone rubber that is 1 mm thick. Results: The results show that varying anvil's angle and surface friction can directly affect the linear and rotational acceleration of the headform. Conclusion: Testing helmets for different oblique impact angles can help assess their protection capability. The coefficient of the friction between the helmet's interior and the headform plays an important role in the headform's rotational acceleration during an impact. Using a standard surface friction for headform similar or close to that of the human scalp can ensure that the results of the oblique impact tests are more consistent and realistic. PMID:25023929

Ebrahimi, Iman; Golnaraghi, Farid; Wang, G Gary

2014-07-14

59

Impact testing of centrifugally cast canisters of simulated waste glass  

SciTech Connect

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

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

1984-10-01

60

Impact Testing of Composites for Aircraft Engine Fan Cases  

NASA Technical Reports Server (NTRS)

Before composite materials can be considered for use in the fan case of a commercial jet engine, the performance of a composite structure under blade-out loads needs to be demonstrated. The objective of this program is to develop an efficient test and analysis method for evaluating potential composite case concepts. Ballistic impact tests were performed on laminated glass/epoxy composites in order to identify potential failure modes and to provide data for analysis. Flat 7x7 in. panels were impacted with cylindrical titanium projectiles, and 15 in. diameter half-rings were impacted with wedge-shaped titanium projectiles. Composite failure involved local fiber fracture as well as tearing and delamination on a larger scale. A 36 in. diameter full-ring subcomponent was proposed for larger scale testing. Explicit, transient, finite element analyses were used to evaluate impact dynamics and subsequent global deformation for the proposed full-ring subcomponent test. Analyses on half-ring and quarter ring configurations indicated that less expensive smaller scale tests could be used to screen potential composite concepts when evaluation of local impact damage is the primary concern.

Roberts, Gary D.; Revilock, Duane M.; Binienda, Wieslaw K.; Nie, Walter Z.; Mackenzie, S. Ben; Todd, Kevin B.

2001-01-01

61

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

62

Marshall Space Flight Center's Impact Testing Facility Capabilities  

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

63

Marshall Space Flight Center's Impact Testing Facility Capabilities  

NASA Technical Reports Server (NTRS)

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

Evans, Steve; Finchum, Andy; Hubbs, Whitney

2008-01-01

64

Comparison of high speed impact test of solder joints with board level drop test  

NASA Astrophysics Data System (ADS)

Efforts have been made in this study to evaluate the characteristics of solder joint failure by using a new high speed impact tester. First, the dynamics and characteristics of the test vehicle in a board level drop test have been evaluated. A thorough understanding of the behavior of the test vehicle is examined by characterizing its response under different test profiles and board dimensions. This is done in an attempt to optimize the test procedure used to qualify electronic products subjected to high strain rate drop/shock environment. The effects of peak acceleration and change in velocity of the impact pulse on the reliability of the test vehicle have been studied. In situ strain measurements have been used to aid us in characterizing the board response under high strain rate loading conditions. Also finite element analysis has been used to better understand the board response under different loading conditions. Based on the experimental results and analysis, ways to improvise the drop test setup have been discussed. A more thorough understanding of the solder joint behavior is examined by characterizing the behavior with respect to varying impact profiles on a new pendulum fatigue and a high speed impact tester. This is done in an attempt to address solder joint failures in actual product that may be operating under high strain rate or shock environments and to reduce the actual test time needed for a board level drop test. Comparison between the high speed pendulum impact test and drop test was primarily made by evaluating the failure modes from these two tests. Energy absorbed by the solder in a single impact has been used to predict the reliability in a board level test.

Guruprasad, Pradosh

65

Hypervelocity impact testing of Shuttle Orbiter thermal protection system tiles  

NASA Technical Reports Server (NTRS)

Results are presented from a series of 22 hypervelocity impact tests carried out on the thermal protection system (TPS) for the Shuttle Orbiter. Both coated and uncoated low-density (0.14 g/cu cm) LI-900 and high-density (0.35 g/cu cm) LI-2200 tiles were tested. The results are used to develop the penetration and damage correlations which can be used in meteoroid and debris hazard analyses for spacecraft with a ceramic tile TPS. It is shown that tile coatings act as a 'bumper' to fragment the impacting projectile, with thicker coating providing increased protection.

Christiansen, Eric L.; Ortega, Javier

1990-01-01

66

Hypervelocity Impact Test Results for a Metallic Thermal Protection System  

NASA Technical Reports Server (NTRS)

Hypervelocity impact tests have been performed on specimens representing metallic thermal protection systems (TPS) developed at NASA Langley Research Center for use on next-generation reusable launch vehicles (RLV). The majority of the specimens tested consists of a foil gauge exterior honeycomb panel, composed of either Inconel 617 or Ti-6Al-4V, backed with 2.0 in. of fibrous insulation and a final Ti-6Al-4V foil layer. Other tested specimens include titanium multi-wall sandwich coupons as well as TPS using a second honeycomb sandwich in place of the foil backing. Hypervelocity impact tests were performed at the NASA Marshall Space Flight Center Orbital Debris Simulation Facility. An improved test fixture was designed and fabricated to hold specimens firmly in place during impact. Projectile diameter, honeycomb sandwich material, honeycomb sandwich facesheet thickness, and honeycomb core cell size were examined to determine the influence of TPS configuration on the level of protection provided to the substructure (crew, cabin, fuel tank, etc.) against micrometeoroid or orbit debris impacts. Pictures and descriptions of the damage to each specimen are included.

Karr, Katherine L.; Poteet, Carl C.; Blosser, Max L.

2003-01-01

67

Impact tests on rubber compression springs for airplane landing gears  

NASA Technical Reports Server (NTRS)

The present report gives the results of tests which were made for the purpose of solving the problem of whether diagrams obtained from pressure tests could be conclusive for the determination of the safe impact coefficients. It is first established that the rubber rings adhere firmly to the compression surfaces during deformation. Suggestions are thus obtained for a constructive simplification of the rubber rings. The hysteresis phenomenon is ascribed to external and internal friction forces. A device for falling tests is then described with which the process of shock absorption with rubber rings was tested.

Hohenemser, K

1930-01-01

68

Neural Networks Analyze Data In Particle-Impact-Noise Tests  

NASA Technical Reports Server (NTRS)

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

Scaglione, Lois J.

1995-01-01

69

Impact Testing of a Stirling Converter's Linear Alternator  

NASA Technical Reports Server (NTRS)

The U.S. Department of Energy (DOE), in conjunction with the NASA John H. Glenn Research Center and Stirling Technology Company, are currently developing a Stirling convertor for a Stirling Radioisotope Generator (SRG). NASA Headquarters and DOE have identified the SRG for potential use as an advanced spacecraft power system for future NASA deep-space and Mars surface missions. Low-level dynamic impact tests were conducted at NASA Glenn Research Center's Structural Dynamics Laboratory as part of the development of this technology. The purpose of this test was to identify dynamic structural characteristics of the Stirling Technology Demonstration Convertor (TDC). This paper addresses the test setup, procedure, and results of the impact testing conducted on the Stirling TDC in May 2001.

Suarez, Vicente J.; Goodnight, Thomas W.; Hughes, William O.; Samorezov, Sergey

2002-01-01

70

Hypervelocity impact testing of pressure vessels to simulate spacecraft failure  

Microsoft Academic Search

A series of hypervelocity impact tests are conducted against thin-walled aluminum pressure vessels to investigate failure mechanisms. The vessels, 0.05 and 0.08 inches thick, are constructed to replicate the material properties of the International Space Station (ISS). The vessels are pressurized to simulate the conditions experienced by the habitable modules of the ISS. A test matrix incorporating shielded thin plates,

Gregory D. Olsen; Angela M. Nolen

2001-01-01

71

Large Field Photogrammetry Techniques in Aircraft and Spacecraft Impact Testing  

NASA Technical Reports Server (NTRS)

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

Littell, Justin D.

2010-01-01

72

End-on radioisotope thermoelectric generator impact tests  

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). 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.; Hinckley, J. E.

1997-01-01

73

Low-Velocity Impact Testing Horacio Dante Espinosa, Northwestern University  

E-print Network

are further classi- fied as nonrecovery or recovery experiments. The focus of this article is on plate, or rod-on-rod experiments. Two types of plate-on-plate impact tests have been devel- oped: wave propagation experiments and thin-layer high-strain-rate experiments. The plate-on-plate experiments

Espinosa, Horacio D.

74

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

75

West Valley Demonstration Project full-scale canister impact tests  

SciTech Connect

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 stainless steel canisters were approximately 85% filled with simulated vitrified waste and weighed about 2100 kg (4600 lb). Each canister was dropped vertically from a height of 7 m (23 ft) onto an essentially unyielding surface. The integrity of the canister was determined by the application and analysis of strain circles, dimensional measurements, and helium leak testing. The canisters were also visually inspected before and after the drop for physical damage. After the impact, very little deformation of the canisters was observed. The strain circles deformed in the axial direction less than 3% and up to 7% in the hoop direction. The canisters on average showed a slight diameter increase of approximately 2% (1 to 2 cm) in the area nearest to the bottom head. The diameter only increased an average of 0.8% (0.5 cm) at the 76-cm elevation. The canister height decreased by an average of 0.4% (1.2 cm). Helium leak testing of each weld showed either no detectable leaks or very slight leaks much less than the acceptance criteria of 10{sup {minus}4} atm cc/sec. Each of the canisters passed the ``straightness`` test in which the canisters were fit into an inspection sleeve, a straight cylinder with a 63.5-cm (25 in) diameter, after the impact. The results of the impact test verify that the canisters survived the 7-m drops unbreached. Therefore, these results demonstrate that the reference canister meets the drop test specification of the Waste Acceptance Product Specification.

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

1995-12-31

76

Multidimensional Validation Impact Tests on PZT 95/5  

NASA Astrophysics Data System (ADS)

A family of nonplanar impact tests has been conducted on the ferrelectric ceramic PZT 95/5 and alumina-loaded epoxy (ALOX) encapsulants, with the purpose of providing benchmarks for material models in the ALEGRA wavecode. Diagnostics used included line-imaging and multipoint VISAR (velocity interferometry). Results from four tests conducted with ALOX cylinders impacted by nonplanar copper projectiles were compared with ALEGRA simulations. The simulations produced approximately correct attenuations and divergence, but significantly low wave velocities. Adjusting parameters improve the wave velocity agreement. Several sets of tests conducted using PZT rods (length:diameter = 5:1) encapsulated in ALOX, and diagnosed with line-imaging and point VISAR, were modeled as well.

Furnish, Michael D.; Robbins, Joshua; Trott, Wayne M.; Chhabildas, Lalit C.; Lawrence, R. Jeffery; Montgomery, Stephen T.

2001-06-01

77

Hydrodynamic impact analysis and testing of an unmanned aerial vehicle  

NASA Astrophysics Data System (ADS)

Analysis and testing have been conducted to assess the feasibility of a small UAV that can be landed in the water and recovered for continued use. Water landings may be desirable in a number of situations, for example when testing UAVs outside of the territorial waters of the US to avoid violating FAA regulations. Water landings may also be desirable when conducting surveillance missions in marine environments. Although the goal in landing is to have the UAV lightly set down on the water, rough seas or gusty winds may result in a nose-in landing where the UAV essentially impacts the surface of the water. The tested UAV is a flying wing design constructed of expanded polypropylene foam wings with a hollowed out center-section for the avionics. Acceleration data was collected by means of LIS331 3-axis accelerometers positioned at five locations, including the wingtips. This allowed conclusions to be drawn with respect to the loads experienced on impact throughout the airframe. This data was also used to find loads corresponding to the maximum decelerations experienced during impact. These loads were input into a finite element analysis model of the wing spars to determine stress in the wing spars. Upon impact, the airframe experienced high-frequency oscillation. Surprisingly, peak accelerations at the wingtips were observed at up to 15g greater than corresponding accelerations at the center of the fuselage.

Bird, Isabel

78

Space Shuttle Main Engine Debris Testing Methodology and Impact Tolerances  

NASA Technical Reports Server (NTRS)

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

Gradl, Paul R.; Stephens, Walter

2005-01-01

79

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

80

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

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

81

Simulated hail impact testing of photovoltaic solar panels  

NASA Technical Reports Server (NTRS)

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 tested. It was found that none of the six panel designs incorporating clear potting silicone material as the outermost layer remained undamaged by 1-in. simulated hailstones, while a photovoltaic module equipped with a 0.188-in.-thick acrylic cover sheet would be able to withstand the impact of a 2-in.-diameter hailstone.

Moore, D.; Wilson, A.; Ross, R.

1978-01-01

82

Ductile damage evolution in high purity copper taylor impact test  

NASA Astrophysics Data System (ADS)

Recently, the continuum damage mechanics model proposed by Bonora (Eng. Fract. Mech. 58, 1997) has been updated to account for stress triaxiality effect on model parameters, (Bonora et al., AIP Conf. Proc. 1195, 2009). This model enhancement allows to predict ductile damage initiation under varying stress states (uniaxial stress, uniaxial strain, and complex load paths) and dynamic loading conditions. In this work, the model has been used to investigate ductile damage developments in Taylor anvil and symmetric Taylor impact (rod-on-rod) configuration. Although the two configurations are equivalent for right scaled impact velocities, experimental evidences show that when ductile damage occurs in rod-on-rod not necessarily also develops in Taylor anvil impact. It has been found that, in the two impact configurations, the stress triaxiality builds up differently with plastic strain leading to different conditions for ductile damage initiation. Taylor impact tests have been designed and performed with the gas-gun facility at the University of Cassino. Damage investigation results obtained on recovered samples have been compared with rod-on-rod data reported in the literature and used to validate the proposed model predictions.

Bonora, Nicola; Ruggiero, Andrew; Iannitti, Gianluca; Testa, Gabriel

2012-03-01

83

Impact testing of a Stirling convertor’s linear alternator  

Microsoft Academic Search

The U.S. Department of Energy (DOE), in conjunction with NASA John H. Glenn Research Center and Stirling Technology Company, are currently developing a Stirling convertor for a Stirling Radioisotope Generator (SRG). NASA Headquarters and DOE have identified the SRG for potential use as an advanced spacecraft power system for future NASA deep-space and Mars surface missions. Low-level dynamic impact tests

Vicente J. Sua´rez; Thomas W. Goodnight; William O. Hughes; Sergey Samorezov

2002-01-01

84

Single and multiple impact ignition of new and aged high explosives in the Steven Impact Test  

SciTech Connect

Threshold impact velocities for ignition of exothermic reaction were determined for several new and aged HMX-based solid high explosives using three types of projectiles in the Steven Test. Multiple impact threshold velocities were found to be approximately 10% lower in damaged charges that did not react in one or more prior impacts. Projectiles with protrusions that concentrate the friction work in a small volume of explosive reduced the threshold velocities by approximately 30%. Flat projectiles required nearly twice as high velocities for ignition as rounded projectiles. Blast overpressure gauges were used for both pristine and damaged charges to quantitatively measure reaction violence. Reactive flow calculations of single and multiple impacts with various projectiles suggest that the ignition rates double in damaged charges.

Chidester, S K; DePiero, A H; Garza, R G; Tarver, C M

1999-06-01

85

Data Reduction and Its Impact on Test-Analysis Correlation  

NASA Technical Reports Server (NTRS)

A research project has been initiated to improve crash test and analysis correlation. The research has focused on two specimen types: simple metallic beams and plates; and a representative composite fuselage section. Impact tests were performed under carefully controlled conditions. In addition, the specimens were densely instrumented to enable not only correlation with finite element simulations, but to also assess the repeatability of the data. Simulations utilizing a detailed finite element model were executed in a nonlinear transient dynamic code. The results presented in this paper concentrate on the effect of several data reduction processes, to include filtering frequency and sampling rate, on the correlation accuracy.

Lyle, Karen H.; Bark, Lindley W.

2001-01-01

86

Arcjet Testing of Micro-Meteoroid Impacted Thermal Protection Materials  

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

87

West Valley Demonstration Project full-scale canister impact tests  

SciTech Connect

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

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

1995-09-01

88

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

89

Tensile and impact properties of V-4Cr-4Ti alloy heats 832665 and 832864.  

SciTech Connect

Two large heats of V-4Cr-4Ti alloy were produced in the United States in the past few years. The first, 832665, was a 500 kg heat procured by the U.S. Department of Energy for basic fusion structural materials research. The second, 832864, was a 1300 kg heat procured by General Atomics for the DIII-D radiative divertor upgrade. Both heats were produced by Oremet-Wah Chang (previously Teledyne Wah Chang of Albany). Tensile properties up to 800 C and Charpy V-notch impact properties down to liquid nitrogen temperature were measured for both heats. The product forms tested for both heats were rolled sheets annealed at 1000 C for 1 h in vacuum. Testing results show the behavior of the two heats to be similar and the reduction of strengths with temperature to be insignificant up to at least 750 C. Ductility of both materials is good in the test temperature range. Impact properties for both heats are excellent--no brittle failures at temperatures above -150 C. Compared to the data for previous smaller laboratory heats of 15-50 kg, the results show that scale-up of vanadium alloy ingot production to sizes useful for reactor blanket design can be successfully achieved as long as reasonable process control is implemented.

Bray, T. S.; Tsai, H.; Nowicki, L. J.; Billone, M. C.; Smith, D. L.; Johnson, W. R.; Trester, P. W.

1999-11-08

90

Sand Impact Tests of a Half-Scale Crew Module Boilerplate Test Article  

NASA Technical Reports Server (NTRS)

Although the Orion Multi-Purpose Crew Vehicle (MPCV) is being designed primarily for water landings, a further investigation of launch abort scenarios reveals the possibility of an onshore landing at Kennedy Space Center (KSC). To gather data for correlation against simulations of beach landing impacts, a series of sand impact tests were conducted at NASA Langley Research Center (LaRC). Both vertical drop tests and swing tests with combined vertical and horizontal velocity were performed onto beds of common construction-grade sand using a geometrically scaled crew module boilerplate test article. The tests were simulated using the explicit, nonlinear, transient dynamic finite element code LS-DYNA. The material models for the sand utilized in the simulations were based on tests of sand specimens. Although the LSDYNA models provided reasonable predictions for peak accelerations, they were not always able to track the response through the duration of the impact. Further improvements to the material model used for the sand were identified based on results from the sand specimen tests.

Vassilakos, Gregory J.; Hardy, Robin C.

2012-01-01

91

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

SciTech Connect

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

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

1993-10-25

92

Impact of looping on middle school science standardized achievement tests  

NASA Astrophysics Data System (ADS)

Looping may be defined as a teacher remaining with a group of students for multiple academic years. In this quantitative study, looping was examined as a factor on science achievement. State-wide eighth grade school level 2010 Pennsylvania System of School Assessment (PSSA) data were used. By responding to a mailing, school administrators indicated if 2010 eighth grade students had or had not been looped. The schools' percentage of advanced and proficient Science PSSA data were used to determine if the independent variable had a significant impact on science achievement. The results of the independent t-test analysis suggest that looping does not contribute to science achievement for this study sample.

Barger, Tammy M.

93

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. PMID:10875672

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

2000-01-01

94

Dynamic Impact Analyses and Tests of Concrete Overpacks - 13638  

SciTech Connect

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

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

2013-07-01

95

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

96

49 CFR 572.126 - Knees and knee impact test procedure.  

Code of Federal Regulations, 2010 CFR

...ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Six-year-old Child Test Dummy, Beta Version § 572.126 Knees and knee impact test procedure. (a) Knee assembly. The knee assembly is part of the leg...

2010-10-01

97

49 CFR 572.136 - Knees and knee impact test procedure.  

Code of Federal Regulations, 2010 CFR

...ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Hybrid III 5th Percentile Female Test Dummy, Alpha Version § 572.136 Knees and knee impact test procedure. (a) Knee assembly. The knee assembly (refer...

2010-10-01

98

49 CFR 572.166 - Knees and knee impact test procedure.  

Code of Federal Regulations, 2010 CFR

...NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly...

2010-10-01

99

Compression After Impact Testing of Sandwich Structures Using the Four Point Bend Test  

NASA Technical Reports Server (NTRS)

For many composite laminated structures, the design is driven by data obtained from Compression after Impact (CAI) testing. There currently is no standard for CAI testing of sandwich structures although there is one for solid laminates of a certain thickness and lay-up configuration. Most sandwich CAI testing has followed the basic technique of this standard where the loaded ends are precision machined and placed between two platens and compressed until failure. If little or no damage is present during the compression tests, the loaded ends may need to be potted to prevent end brooming. By putting a sandwich beam in a four point bend configuration, the region between the inner supports is put under a compressive load and a sandwich laminate with damage can be tested in this manner without the need for precision machining. Also, specimens with no damage can be taken to failure so direct comparisons between damaged and undamaged strength can be made. Data is presented that demonstrates the four point bend CAI test and is compared with end loaded compression tests of the same sandwich structure.

Nettles, Alan T.; Gregory, Elizabeth; Jackson, Justin; Kenworthy, Devon

2008-01-01

100

Wavelet analysis in ecology and epidemiology: impact of statistical tests  

PubMed Central

Wavelet analysis is now frequently used to extract information from ecological and epidemiological time series. Statistical hypothesis tests are conducted on associated wavelet quantities to assess the likelihood that they are due to a random process. Such random processes represent null models and are generally based on synthetic data that share some statistical characteristics with the original time series. This allows the comparison of null statistics with those obtained from original time series. When creating synthetic datasets, different techniques of resampling result in different characteristics shared by the synthetic time series. Therefore, it becomes crucial to consider the impact of the resampling method on the results. We have addressed this point by comparing seven different statistical testing methods applied with different real and simulated data. Our results show that statistical assessment of periodic patterns is strongly affected by the choice of the resampling method, so two different resampling techniques could lead to two different conclusions about the same time series. Moreover, our results clearly show the inadequacy of resampling series generated by white noise and red noise that are nevertheless the methods currently used in the wide majority of wavelets applications. Our results highlight that the characteristics of a time series, namely its Fourier spectrum and autocorrelation, are important to consider when choosing the resampling technique. Results suggest that data-driven resampling methods should be used such as the hidden Markov model algorithm and the ‘beta-surrogate’ method. PMID:24284892

Cazelles, Bernard; Cazelles, Kévin; Chavez, Mario

2014-01-01

101

Measurement of Satellite Impact Test Fragments for Modeling Orbital Debris  

NASA Technical Reports Server (NTRS)

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

Hill, Nicole M.

2009-01-01

102

A New Scale Measuring Psychologic Impact of Genetic Susceptibility Testing for Alzheimer Disease  

Microsoft Academic Search

This paper describes the development and psycho- metric properties of a new scale for assessing the psychologic impact of genetic susceptibility testing for Alzheimer disease (AD). The new instrument, The REVEAL Impact of Genetic Testing for Alzheimer's disease (IGT-AD) was designed to examine the unique nature of genetic information and the disease course of AD. The scale was tested as

Winston W. Chung; Clara A. Chen; L. Adrienne Cupples; J. Scott Roberts; Susan C. Hiraki; Anil K. Nair; Robert C. Green; Robert A. Stern

2009-01-01

103

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

104

Irradiation effects on Charpy impact and tensile properties of low upper-shelf welds, HSSI series 2 and 3  

SciTech Connect

When reactor pressure vessel steels exhibit Charpy V-notch impact upper-shelf energy levels of less than 68 J (50 ft-lb), the requirements of Title 10, Code of Federal Regulations, Part 50, Appendix G, are not met. The regulations require, as an option, that a fracture mechanics analysis be performed that conservatively demonstrates adequate safety margins for continued operation. Under conditions where large prefracture crack-tip plastic zones are present, linear-elastic fracture mechanics concepts are not applicable, and the use of elastic-plastic fracture mechanics concepts has been recommended by the US Nuclear Regulatory Commission. A number of Babcock and Wilcox Company-fabricated reactor vessels in commercial pressurized water reactor plants include welds with both relatively low initial Charpy upper-shelf energies and high copper concentrations, which make them highly sensitive to neutron irradiation. As a result, the Charpy upper-shelf energies of many welds are expected to fall below 68 J (50 ft-lb) prior to reaching design life. The Heavy-Section Steel Irradiation Program conducted the Second and Third Irradiation Series to investigate the effects of irradiation on the ductile fracture toughness of seven commercially fabricated, low upper-shelf welds. This report represents analyses of the Charpy impact and tensile test data, including adjustments for irradiation temperature and fluence normalization, which make possible comparison of the irradiation sensitivity the different welds.

Nanstad, R.K.; Berggren, R.G. (Oak Ridge National Lab., TN (United States))

1991-08-01

105

Impact of Proficiency Testing on Results of the Microscopic Agglutination Test for Diagnosis of Leptospirosis  

PubMed Central

A proficiency testing scheme for the leptospirosis microscopic agglutination test was provided to 37 laboratories in 23 countries in 2002 (round 1) and to 60 laboratories in 34 countries in 2003 (round 2). Thirty-four laboratories participated in both rounds. Each panel consisted of five rabbit serum samples, four of which were antisera raised against pathogenic serovars of Leptospira. One of these samples was a mixture of two different antisera. The rates of false-negative results, calculated on the basis of the assumption that serovars within a serogroup will cross-react, were 11% for round 1 and 14% for round 2. There were regional differences in the rates of false-negative results. The titers reported by laboratories testing for the same sample with the same serovar varied widely. Laboratories that had previously participated in round 1 reported fewer false-negative results in round 2 than new participants (10 and 21%, respectively [P = 0.002]) and reported 0.56 false-negative results per participant, whereas new participants reported 1.23 false-negative results per participant (P = 0.041). Laboratories that had previously participated also reported fewer false-negative results in round 2 than in round 1 when samples common to both rounds were tested (5 and 15%, respectively [P = 0.028]). The titers reported by the new participants were, on average, lower than those reported by the laboratories that had participated previously (P = 0.019) and were significantly more variable (P = 0.001). Analysis of these results suggests a positive impact of proficiency testing on the testing performance of the participating laboratories. PMID:15583270

Chappel, R. J.; Goris, M.; Palmer, M. F.; Hartskeerl, R. A.

2004-01-01

106

Orion MPCV Water Landing Test at Hydro Impact Basin - Duration: 1:17.  

NASA Video Gallery

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

107

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

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

108

16 CFR 1203.17 - Impact attenuation test.  

Code of Federal Regulations, 2012 CFR

...plus a height adjustment to account for friction losses.) Six impacts, at intervals...plus a height adjustment to account for friction losses.) The helmet shall be dropped...plus a height adjustment to account for friction losses.) The impact velocity...

2012-01-01

109

16 CFR 1203.17 - Impact attenuation test.  

Code of Federal Regulations, 2013 CFR

...plus a height adjustment to account for friction losses.) Six impacts, at intervals...plus a height adjustment to account for friction losses.) The helmet shall be dropped...plus a height adjustment to account for friction losses.) The impact velocity...

2013-01-01

110

16 CFR 1203.17 - Impact attenuation test.  

Code of Federal Regulations, 2014 CFR

...plus a height adjustment to account for friction losses.) Six impacts, at intervals...plus a height adjustment to account for friction losses.) The helmet shall be dropped...plus a height adjustment to account for friction losses.) The impact velocity...

2014-01-01

111

WIND TUNNEL TESTING AND COMPARISON OF THREE SALTATION IMPACT SENSORS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Saltation impact sensors are used to investigate the temporal and spatial fluctuations of saltation intensity over eroding surfaces. Three types of impact sensors have been used by various researchers; the Saltiphone, the Sensit, and the Safire. In spite of the wide-spread use of these devices by ...

112

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

NASA Technical Reports Server (NTRS)

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

Probst, H B; Mchenry, Howard T

1957-01-01

113

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

Microsoft Academic Search

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

Younghan Youn; Jeong-Seo Koo

2008-01-01

114

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

2012-09-01

115

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

116

Private Water Well Testing in Areas Impacted by Marcellus Shale Gas Drilling  

E-print Network

Private Water Well Testing in Areas Impacted by Marcellus Shale Gas Drilling (Updated November 15th in the absence of shale-gas drilling, well owners are strongly encouraged to evaluate their water on a regular testing in order to more specifically document potential impacts of Marcellus Shale gas development

Manning, Sturt

117

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

118

Hypervelocity Impact Testing of IM7/977-3 with Micro-Sized Particles  

NASA Technical Reports Server (NTRS)

Ground-based hypervelocity imapct testing was conducted on IM7/977-3 quasi-isotropic flat panels at normal incidence using micron-sized particles (i.e. less than or equal to 100 microns) of soda lime glass and olivine. Testing was performed at room temperature (RT) and 175 C with results from the 175 C test compared to those obtained at RT. Between 10 and 30 particles with velocities ranging from 5 to 13 km/s impacted each panel surface for each test temperature. Panels were ultrasonically scanned prior to and after impact testing to assess internal damage. Post-impact analysis included microscopic examination of the surface, determination of particle speed and location, and photomicroscopy for microcrack assessment. Internal damage was observed by ultrasonic inspection on panels impacted at 175 C, whereas damage for the RT impacted panels was confined to surface divets/craters as determined by microscopic analysis.

Smith, J. G.; Jegley, D. C.; Siochi, E. J.; Wells, B. K.

2010-01-01

119

Hypervelocity Impact Testing of Space Station Freedom Solar Cells  

NASA Technical Reports Server (NTRS)

Solar array coupons designed for the Space Station Freedom electrical power system were subjected to hypervelocity impacts using the HYPER facility in the Space Power Institute at Auburn University and the Meteoroid/Orbital Debris Simulation Facility in the Materials and Processes Laboratory at the NASA Marshall Space Flight Center. At Auburn, the solar cells and array blanket materials received several hundred impacts from particles in the micron to 100 micron range with velocities typically ranging from 4.5 to 10.5 km/s. This fluence of particles greatly exceeds what the actual components will experience in low earth orbit. These impacts damaged less than one percent of total area of the solar cells and most of the damage was limited to the cover glass. There was no measurable loss of electrical performance. Impacts on the array blanket materials produced even less damage and the blanket materials proved to be an effective shield for the back surface of the solar cells. Using the light gas gun at MSFC, one cell of a four cell coupon was impacted by a 1/4 inch spherical aluminum projectile with a velocity of about 7 km/s. The impact created a neat hole about 3/8 inch in diameter. The cell and coupon were still functional after impact.

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

1994-01-01

120

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

NASA Astrophysics Data System (ADS)

The complete evaluation of the side vehicle structure and the occupant protection is only possible by means of the full scale side impact crash test. But, auto part manufacturers such as door trim makers can not conduct the test especially when the vehicle is under the developing process. The main objective of this study is to obtain the design guidelines by a simple component level impact test. The relationship between the target absorption energy and impactor speed were examined using the energy absorbed by the door trim. Since each different vehicle type required different energy levels on the door trim. A simple impact test method was developed to estimate abdominal injury by measuring reaction force of the impactor. The reaction force will be converted to a certain level of the energy by the proposed formula. The target of absorption energy for door trim only and the impact speed of simple impactor are derived theoretically based on the conservation of energy. With calculated speed of dummy and the effective mass of abdomen, the energy allocated in the abdomen area of door trim was calculated. The impactor speed can be calculated based on the equivalent energy of door trim absorbed during the full crash test. With the proposed design procedure for the door trim by a simple impact test method was demonstrated to evaluate the abdominal injury. This paper describes a study that was conducted to determine sensitivity of several design factors for reducing abdominal injury values using the matrix of orthogonal array method. In conclusion, with theoretical considerations and empirical test data, the main objective, standardization of door trim design using the simple impact test method was established.

Youn, Younghan; Koo, Jeong-Seo

121

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

122

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

123

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

124

MultiDimensional Validation Impact Tests on PZT 95\\/5 and ALOX  

Microsoft Academic Search

Multi-dimensional impact tests were conducted on the ferroelectric ceramic PZT 95\\/5 and alumina-loaded epoxy (ALOX) encapsulants, with the purpose of providing benchmarks for material models in the ALEGRA wavecode. Diagnostics used included line-imaging VISAR (velocity interferometry), a key diagnostic for such tests. Results from four tests conducted with ALOX cylinders impacted by nonplanar copper projectiles were compared with ALEGRA simulations.

M. D. Furnish; J. Robbins; W. M. Trott; L. C. Chhabildas; R. J. Lawrence; S. T. Montgomery

2002-01-01

125

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

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

126

Impact resistance of current design composite fan blades tested under short-haul operating conditions  

NASA Technical Reports Server (NTRS)

Boron/epoxy and graphite/epoxy composite blades were impacted in a rotating whirligig facility with conditions closely simulating those which might be experienced by a STOL engine impacted with various foreign objects. The tip speed of the rotating blades was 800 feet per second. The blades were impacted with simulated birds, real birds, ice balls, and gravel. The results of composite blade impact tests were compared with a titanium blade tested under similar conditions. Neither composite material indicated a clear superiority over the other. Blades made from both composite materials showed more damage than the titanium blades.

Steinhagen, C. A.; Salemme, C. T.

1973-01-01

127

Hypervelocity impact testing of non-metallic materials  

NASA Technical Reports Server (NTRS)

A comparative analysis of impact damage in composite and ceramic specimens and in geometrically similar aluminum specimens is performed to determine the advantages and disadvantages of employing certain composite and ceramic materials in the design of structural wall systems for long-duration spacecraft. A similar analysis of the damage in single panel lexan and multi-plane glass windows shows that glass window systems are rather resilent under hypervelocity impact loadings. It is concluded that thin Kevlar 49, IM6/3501-6 graphite/epoxy, and alumina panels offer no advantage over equivalent aluminum 6061-T6 panels in reducing the penetration threat of hypervelocity projectiles.

Schonberg, William P.

1990-01-01

128

Soft Soil Impact Testing and Simulation of Aerospace Structures  

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

129

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

PubMed Central

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

Vasconcelos, Vitor; Antunes, Agostinho

2014-01-01

130

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

NASA Technical Reports Server (NTRS)

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

Vassilakos, Gregory J.

2014-01-01

131

The impact of test anxiety on metacognitive knowledge monitoring  

Microsoft Academic Search

The research goal of this study was to investigate the impact of anxiety on various metacognitive and academic tasks. Of primary concern was the effect of anxiety on students' metacognitive knowledge monitoring, ability to study strategically, and academic performance. The relationship between these variables was examined and expected to differ for students with varying levels of state and trait anxiety.

Julie Suzanne Nathan

2000-01-01

132

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

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

133

The impact of test case reduction and prioritization on software testing effectiveness  

Microsoft Academic Search

Software testing is critical but most expensive phase of Software Development Life Cycle (SDLC). Development organizations desire to thoroughly test the software. But this exhaustive testing is impractical due to resource constraints. A large number of test suites are generated using automated tools. But the real challenge is the selection of subset of test cases and\\/or high order test cases

S. u. R. Khan; I. u. Rehman; S. U. R. Malik

2009-01-01

134

Charpy Impact Testing University of Saskatchewan -Mechanical Engineering -Materials Science and Metallurgy  

E-print Network

and Metallurgy ID: Mat0020 Rev: 002 Date: Nov. 8, 2011 Page: 1 of 6 Impact Testing with the Charpy Impact Tester - Materials Science and Metallurgy ID: Mat0020 Rev: 002 Date: Nov. 8, 2011 Page: 2 of 6 1. SIGNATURES Science and Metallurgy ID: Mat0020 Rev: 002 Date: Nov. 8, 2011 Page: 3 of 6 2. VERSION HISTORY Handwritten

Saskatchewan, University of

135

Detection of Cracks in Single-Crystalline Silicon Wafers Using Impact Testing  

Microsoft Academic Search

This thesis is about detection of cracks in single-crystalline silicon wafers by using a vibration method in the form of an impact test. The goal to detect cracks from vibration measurements introduced by striking the silicon wafer with an impact hammer. Such a method would reduce costs in the production of solar cells. It is an inexpensive, relatively simple method

Christina Hilmersson

2006-01-01

136

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

137

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

E-print Network

but nearly ubiquitous melt that has been continuously created by hypervelocity impacts over nearly all strewn fields, and spherule layers in ancient sediments (Dressler and Reimold, 2001; Koeberl, 1986; Lowe

Stewart, Sarah T.

138

Vertical drop impact test system for biomechanical injury assessment: design validation and model development  

Microsoft Academic Search

An investigation was made of the validity and repeatability of a vertical drop impact test system (VDITS), through experimental comparison to free-fall test results at an impact velocity of 5.5 mph. The VDITS is designed to simulate the dynamics of traumatic injury to the head and chest. Comparison of the two systems was based on force\\/moment and kinematic histories, multiaxis

D. Schmaltz; G. F. Harris; N. Yogananadan; F. Pintar

1989-01-01

139

Particle Impact Ignition Test Data on a Stainless Steel Hand Valve  

NASA Technical Reports Server (NTRS)

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

Peralta, Stephen

2010-01-01

140

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

141

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

142

Impact of a Rapid Respiratory Panel Test on Patient Outcomes.  

PubMed

Context .- Evolution of polymerase chain reaction testing for infectious pathogens has occurred concurrent with a focus on value-based medicine. Objective .- To determine if implementation of the FilmArray rapid respiratory panel (BioFire Diagnostics, Salt Lake City, Utah) (hereafter RRP), with a shorter time to the test result and expanded panel, results in different outcomes for children admitted to the hospital with an acute respiratory tract illness. Design .- Patient outcomes were compared before implementation of the RRP (November 1, 2011, to January 31, 2012) versus after implementation of the RRP (November 1, 2012, to January 31, 2013). The study included inpatients 3 months or older with an acute respiratory tract illness, most admitted through the emergency department. Testing before RRP implementation used batched polymerase chain reaction analysis for respiratory syncytial virus and influenza A and B, with additional testing for parainfluenza 1 through 3 in approximately 11% of patients and for human metapneumovirus in less than 1% of patients. The RRP tested for respiratory syncytial virus, influenza A and B, parainfluenza 1 through 4, human metapneumovirus, adenovirus, rhinovirus/enterovirus, and coronavirus NL62. Results .- The pre-RRP group had 365 patients, and the post-RRP group had 771 patients. After RRP implementation, the mean time to the test result was shorter (383 minutes versus 1119 minutes, P < .001), and the percentage of patients with a result in the emergency department was greater (51.6% versus 13.4%, P < .001). There was no difference in whether antibiotics were prescribed, but the duration of antibiotic use was shorter after RRP implementation (P = .003) and was dependent on receiving test results within 4 hours. If the test result was positive, the inpatient length of stay (P = .03) and the time in isolation (P = .03) were decreased after RRP implementation compared with before RRP implementation. Conclusion .- The RRP decreases the duration of antibiotic use, the length of inpatient stay, and the time in isolation. PMID:25152311

Rogers, Beverly B; Shankar, Prabhu; Jerris, Robert C; Kotzbauer, David; Anderson, Evan J; Watson, J Renee; O'Brien, Lauren A; Uwindatwa, Francine; McNamara, Kelly; Bost, James E

2014-08-25

143

The impact of multiplex genetic testing on disease risk perceptions.  

PubMed

This study assessed the effects of multiplex genetic testing on disease risk perceptions among 216 healthy adults. Participants, aged 25-40, were recruited through the Multiplex Initiative, which offered a genetic susceptibility test for eight common diseases. Participants completed baseline telephone and web-based surveys prior to making the testing decision. Three months after the receipt of mailed test results, participants completed a follow-up telephone survey. Risk perceptions for the eight diseases were measured at baseline and follow-up, along with beliefs about genetic causation of those diseases. The main results were: (i) mean risk perceptions were considerably stable from baseline to follow-up; (ii) the best predictors of follow-up risk perceptions were the corresponding baseline perceptions and family history; and (iii) within-individuals, most participants increased or decreased their risk perceptions for specific diseases in concordance with the number of risk markers they carry, their family history and their beliefs about genetic causality of diseases. In conclusion, participants presented a vigilant approach to the interpretation of genetic test results, which provides reassurance with regard to a potential inflation of risk perceptions in the population because of multiplex genetic testing. PMID:24720448

Shiloh, S; deHeer, H D; Peleg, S; Hensley Alford, S; Skapinsky, K; Roberts, J S; Hadley, D W

2015-02-01

144

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

145

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

146

SRB/FWC water impact: Flexible body loads test  

NASA Technical Reports Server (NTRS)

Two technical areas were examined: evaluation of potential correction methods for spurious case strain outputs from the pressure transducers during the NSWC tests; and assessing procedures for modifying either the excitation function or the response function to account for hydroelastic effects.

1984-01-01

147

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

PubMed Central

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

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

2014-01-01

148

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

PubMed

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

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

2014-01-01

149

Ventilation System Effectiveness and Tested Indoor Air Quality Impacts  

SciTech Connect

Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. It was inferior because the source of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.

Rudd, A.; Bergey, D.

2014-02-01

150

Investigation of Pb-free solder interconnect under drop impact by ball pull and shear tests  

Microsoft Academic Search

The reliability of Pb-free solder interconnect under drop impact was investigated. In this paper, solder ball pull and shear tests were introduced to assess the interconnect reliability since high speed pull and shear tests exhibit high strain rate deformation followed by brittle fracture of actual drop scenario. The design, material, and process parameters considered in this study are SR condition,

Soon-Wan Chung; Mi-Jin Kim

2010-01-01

151

The Impact of Linking Distinct Achievement Test Scores on the Interpretation of Student Growth in Achievement  

ERIC Educational Resources Information Center

Changes to state tests impact the ability of State Education Agencies (SEAs) to monitor change in performance over time. The purpose of this study was to evaluate the Standardized Performance Growth Index (PGIz), a proposed statistical model for measuring change in student and school performance, across transitions in tests. The PGIz is a…

Airola, Denise Tobin

2011-01-01

152

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

153

Penetration tests on the DS2 Mars microprobes: penetration depth and impact accelerometry  

Microsoft Academic Search

We describe the results of three separate sets of impact tests conducted during the development of the DS-2 Mars Microprobe mission. As well as indicating the promise of penetration to ?0.5 m depth on Mars, these tests show the utility of accelerometer data in determining the penetration depth, the hardness of the surface material and the existence of layers, and the

Ralph D Lorenz; Jeffrey E Moersch; J. Andy Stone; A Ron Morgan; Suzanne E Smrekar

2000-01-01

154

Penetration tests on the DS2 Mars microprobes: penetration depth and impact accelerometry  

Microsoft Academic Search

We describe the results of three separate sets of impact tests conducted during the development of the DS-2 Mars Microprobe mission. As well as indicating the promise of penetration to ~0.5 m depth on Mars, these tests show the utility of accelerometer data in determining the penetration depth, the hardness of the surface material and the existence of layers, and

R. D. Lorenz; J. E. Moersch; J. A. Stone; A. Ron Morgan; S. E. Smrekar

2000-01-01

155

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

ERIC Educational Resources Information Center

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

Schochet, Peter Z.

2009-01-01

156

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

157

Design of Spacecraft Missions to Test Kinetic Impact for Asteroid Deflection  

NASA Technical Reports Server (NTRS)

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

Barbee, Brent W.; Hernandez, Sonia

2012-01-01

158

Nondestructive Evaluation Tests Performed on Space Shuttle Leading- Edge Materials Subjected to Impact  

NASA Technical Reports Server (NTRS)

In support of the space shuttle Return To Flight efforts at the NASA Glenn Research Center, a series of nondestructive evaluation (NDE) tests were performed on reinforced carbon/carbon (RCC) composite panels subjected to ballistic foam impact. The impact tests were conducted to refine and verify analytical models of an external tank foam strike on the space shuttle leading edge. The NDE tests were conducted to quantify the size and location of the resulting damage zone as well as to identify hidden damage.

Roth, Don J.; Martin, Richard E.; Bodis, James R.

2005-01-01

159

Adult headform impact tests of three Japanese child bicycle helmets into a vehicle.  

PubMed

The head is the body region that most frequently incurs fatal and serious injuries of cyclists in collisions against vehicles. Many research studies investigated helmet effectiveness in preventing head injuries using accident data. In this study, the impact attenuation characteristics of three Japanese child bicycle helmets were examined experimentally in impact tests into a concrete surface and a vehicle. A pedestrian adult headform with and without a Japanese child bicycle helmet was dropped onto a concrete surface and then propelled into a vehicle at 35km/h in various locations such as the bonnet, roof header, windshield and A-pillar. Accelerations were measured and head injury criterion (HIC) calculated. In the drop tests using the adult headform onto a concrete surface from the height of 1.5m, the HIC for a headform without a child helmet was 6325, and was reduced by around 80% when a child helmet was fitted to the headform. In the impact tests, where the headform was fired into the vehicle at 35km/h at various locations on a car, the computed acceleration based HIC varied depending on the vehicle impact locations. The HIC was reduced by 10-38% for impacts headforms with a child helmet when the impact was onto a bonnet-top and roof header although the HIC was already less than 1000 in impacts with the headform without a child helmet. Similarly, for impacts into the windshield (where a cyclist's head is most frequently impacted), the HIC using the adult headform without a child helmet was 122; whereas when the adult headform was used with a child helmet, a higher HIC value of more than 850 was recorded. But again, the HIC values are below 1000. In impacts into the A-pillar, the HIC was 4816 for a headform without a child helmet and was reduced by 18-38% for a headform with a child helmet depending on the type of Japanese child helmet used. The tests demonstrated that Japanese child helmets are effective in reducing accelerations and HIC in a drop test using an adult headform onto a relatively rigid hard surface, i.e., simulating a road surface or concrete path. However, when the impact tests are into softer surfaces, the child helmet's capacity to decrease accelerations is accordingly reduced. Impacts into the windshield, while below the critical HIC value of 1000, indicated higher HIC values for a headform with a child helmet compared to an adult headform without a child helmet. The unpredictable nature of the results indicates further research work is required to assess how representative the stiffness of an adult headform is when compared to an actual head. PMID:25290036

Mizuno, Koji; Ito, Daisuke; Yoshida, Ryoichi; Masuda, Hiroyuki; Okada, Hiroshi; Nomura, Mitsunori; Fujii, Chikayo

2014-12-01

160

High-silicon 238PuO2 fuel characterization study: Half module impact tests  

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. 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, Mary Ann H.

1997-01-01

161

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. PMID:18215473

Brown, C. Hendricks; Wang, Wei; Kellam, Sheppard G.; Muthén, 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

162

Impact Testing and Analysis of Composites for Aircraft Engine Fan Cases  

NASA Technical Reports Server (NTRS)

The fan case in a jet engine is a heavy structure because of its size and because of the requirement that it contain a blade released during engine operation. Composite materials offer the potential for reducing the weight of the case. Efficient design, test, and analysis methods are needed to efficiently evaluate the large number of potential composite materials and design concepts. The type of damage expected in a composite case under blade-out conditions was evaluated using a subscale test in which a glass/epoxy composite half-ring target was impacted with a wedge-shaped titanium projectile. Fiber shearing occurred near points of contact between the projectile and target. Delamination and tearing occurred on a larger scale. These damage modes were reproduced in a simpler test in which flat glass/epoxy composites were impacted with a blunt cylindrical projectile. A surface layer of ceramic eliminated fiber shear fracture but did not reduce delamination. Tests on 3D woven carbon/epoxy composites indicated that transverse reinforcement is effective in reducing delamination. A 91 cm (36 in.) diameter full-ring sub-component was proposed for larger scale testing of these and other composite concepts. Explicit, transient, finite element analyses indicated that a full-ring test is needed to simulate complete impact dynamics, but simpler tests using smaller ring sections are adequate when evaluation of initial impact damage is the primary concern.

Roberts, Gary D.; Revilock, Duane M.; Binienda, Wieslaw K.; Nie, Walter Z.; Mackenzie, S. Ben; Todd, Kevin B.

2002-01-01

163

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

Microsoft Academic Search

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

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

1986-01-01

164

An impact excitation system for repeatable, high-bandwidth modal testing of miniature structures  

NASA Astrophysics Data System (ADS)

Miniature components and devices are increasingly seen in a myriad of applications. In general, the dynamic behavior of miniature devices is critical to their functionality and performance. However, modal testing of miniature structures poses many challenges. This paper presents a design and evaluation of an impact excitation system (IES) for repeatable, high-bandwidth, controlled-force modal testing of miniature structures. Furthermore, a dynamic model of the system is derived and experimentally validated to enable the identification of the system parameters that yield single-hit impacts with desired bandwidth and force magnitude. The system includes a small instrumented impact tip attached to a custom designed flexure-based body, an automated electromagnetic release mechanism, and various precision positioners. The excitation bandwidth and the impact force magnitude can be controlled by selecting the system parameters. The dynamic model of the system includes the structural dynamics of the flexure-based body, the electromagnetic force and the associated eddy-current damping, and the impact event. A validation study showed an excellent match between the model simulations and experiments in terms of impact force and bandwidth. The model is then used to create process maps that relate the system parameters to the number of hits (single vs. multiple), the impact force magnitudes and the excitation bandwidths. These process maps can be used to select system parameters or predict system response for a given set of parameters. A set of experiments is conducted to compare the performances of the IES and a (manual) miniature impact hammer. It is concluded that the IES significantly improves repeatability in terms of the impact bandwidth, location, and force magnitude, while providing a high excitation-bandwidth and excellent coherence values. The application of the IES is demonstrated through modal testing of a miniature contact-probe system.

Bediz, Bekir; Korkmaz, Emrullah; Burak Ozdoganlar, O.

2014-06-01

165

Simulated Waste Testing Of Glycolate Impacts On The 2H-Evaporator System  

SciTech Connect

Glycolic acid is being studied as a total or partial replacement for formic acid in the Defense Waste Processing Facility (DWPF) feed preparation process. After implementation, the recycle stream from DWPF back to the high-level waste tank farm will contain soluble sodium glycolate. Most of the potential impacts of glycolate in the tank farm were addressed via a literature review, but several outstanding issues remained. This report documents the non-radioactive simulant tests impacts of glycolate on storage and evaporation of Savannah River Site high-level waste. The testing for which non-radioactive simulants could be used involved the following: the partitioning of glycolate into the evaporator condensate, the impacts of glycolate on metal solubility, and the impacts of glycolate on the formation and dissolution of sodium aluminosilicate scale within the evaporator. The following are among the conclusions from this work: Evaporator condensate did not contain appreciable amounts of glycolate anion. Of all tests, the highest glycolate concentration in the evaporator condensate was 0.38 mg/L. A significant portion of the tests had glycolate concentration in the condensate at less than the limit of quantification (0.1 mg/L). At ambient conditions, evaporator testing did not show significant effects of glycolate on the soluble components in the evaporator concentrates. Testing with sodalite solids and silicon containing solutions did not show significant effects of glycolate on sodium aluminosilicate formation or dissolution.

Martino, C. J.

2013-08-13

166

NASA Marshall Impact Testing Facility Capabilities Applicable to Lunar Dust Work  

NASA Technical Reports Server (NTRS)

The Impact Testing Facility at Marshall Space Flight Center has several guns that would be of use in studying impact phenomena with respect to lunar dust. These include both ballistic guns, using compressed gas and powder charges, and hypervelocity guns, either light gas guns or an exploding wire gun. In addition, a plasma drag accelerator expected to reach 20 km/s for small particles is under development. Velocity determination and impact event recording are done using ultra-high-speed cameras. Simulation analysis is also available using the SPHC hydrocode.

Evans, Steven W.; Finchum, Andy; Hubbs, Whitney; Eskridge, Richard; Martin, Jim

2008-01-01

167

Guidelines for conducting impact tests on shipping packages for radioactive material  

SciTech Connect

Federal regulation (10 CFR Part 71) specifies a number of impact conditions (free-drop, penetration, and puncture), under which a package for the transport of radioactive materials must be tested or evaluated to demonstrate compliance with the regulation. This report is a comprehensive guide to the planning and execution of these impact tests. The report identifies the required considerations for both the design, pre-, and post-test inspections of the test model and the measurement, recording, analysis, and reporting of the test data. The report also presents reasons for the requirements, identifies the major difficulties in meeting these requirements, and suggests possible methods to overcome the difficulties. Discussed in substantial detail is the use of scale models and instrumented measurements.

Mok, G.C.; Carlson, R.W.; Lu, S.C.; Fischer, L.E.

1995-09-01

168

The impact of equilibrium assumptions on tests of selection.  

PubMed

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

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

2013-01-01

169

Dynamic Finite Element Predictions for Mars Sample Return Cellular Impact Test #4  

NASA Technical Reports Server (NTRS)

The nonlinear finite element program MSC.Dytran was used to predict the impact pulse for (he drop test of an energy absorbing cellular structure. This pre-test simulation was performed to aid in the design of an energy absorbing concept for a highly reliable passive Earth Entry Vehicle (EEV) that will directly impact the Earth without a parachute. In addition, a goal of the simulation was to bound the acceleration pulse produced and delivered to the simulated space cargo container. EEV's are designed to return materials from asteroids, comets, or planets for laboratory analysis on Earth. The EEV concept uses an energy absorbing cellular structure designed to contain and limit the acceleration of space exploration samples during Earth impact. The spherical shaped cellular structure is composed of solid hexagonal and pentagonal foam-filled cells with hybrid graphite-epoxy/Kevlar cell walls. Space samples fit inside a smaller sphere at the enter of the EEV's cellular structure. The material models and failure criteria were varied to determine their effect on the resulting acceleration pulse. Pre-test analytical predictions using MSC.Dytran were compared with the test results obtained from impact test #4 using bungee accelerator located at the NASA Langley Research Center Impact Dynamics Research Facility. The material model used to represent the foam and the proper failure criteria for the cell walls were critical in predicting the impact loads of the cellular structure. It was determined that a FOAMI model for the foam and a 20% failure strain criteria for the cell walls gave an accurate prediction of the acceleration pulse for drop test #4.

Fasanella, Edwin L.; Billings, Marcus D.

2001-01-01

170

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

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

171

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

Microsoft Academic Search

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

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

2010-01-01

172

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

NASA Technical Reports Server (NTRS)

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

Prabhakaran, R.; Douglas, Michael J.

2000-01-01

173

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

SciTech Connect

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

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

2012-07-01

174

Impact Foam Testing for Multi-Mission Earth Entry Vehicle Applications  

NASA Technical Reports Server (NTRS)

Multi-Mission Earth Entry Vehicles (MMEEVs) are blunt-body vehicles designed with the purpose of transporting payloads from outer space to the surface of the Earth. To achieve high-reliability and minimum weight, MMEEVs avoid use of limited-reliability systems, such as parachutes and retro-rockets, instead using built-in impact attenuators to absorb energy remaining at impact to meet landing loads requirements. The Multi-Mission Systems Analysis for Planetary Entry (M-SAPE) parametric design tool is used to facilitate the design of MMEEVs and develop the trade space. Testing was conducted to characterize the material properties of several candidate impact foam attenuators to enhance M-SAPE analysis. In the current effort, two different Rohacell foams were tested to determine their thermal conductivity in support of MMEEV design applications. These applications include thermal insulation during atmospheric entry, impact attenuation, and post-impact thermal insulation in support of thermal soak analysis. Results indicate that for these closed-cell foams, the effect of impact is limited on thermal conductivity due to the venting of the virgin material gas and subsequent ambient air replacement. Results also indicate that the effect of foam temperature is significant compared to data suggested by manufacturer's specifications.

Glaab, Louis J.; Agrawal, Paul; Hawbaker, James

2013-01-01

175

Impact Test and Simulation of Energy Absorbing Concepts for Earth Entry Vehicles  

NASA Technical Reports Server (NTRS)

Nonlinear dynamic finite element simulations have been performed to aid in the design of an energy absorbing concept for a highly reliable passive Earth Entry Vehicle (EEV) that will directly impact the Earth without a parachute. EEV's are designed to return materials from asteroids, comets, or planets for laboratory analysis on Earth. The EEV concept uses an energy absorbing cellular structure designed to contain and limit the acceleration of space exploration samples during Earth impact. The spherical shaped cellular structure is composed of solid hexagonal and pentagonal foam-filled cells with hybrid graphite- epoxy/Kevlar cell walls. Space samples fit inside a smaller sphere at the center of the EEV's cellular structure. Comparisons of analytical predictions using MSC,Dytran with test results obtained from impact tests performed at NASA Langley Research Center were made for three impact velocities ranging from 32 to 40 m/s. Acceleration and deformation results compared well with the test results. These finite element models will be useful for parametric studies of off-nominal impact conditions.

Billings, Marcus D.; Fasanella, Edwin L.; Kellas, Sotiris

2001-01-01

176

Dynamic Finite Element Predictions for Mars Sample Return Cellular Impact Test #4  

NASA Technical Reports Server (NTRS)

The nonlinear, transient dynamic finite element code, MSC.Dytran, was used to simulate an impact test of an energy absorbing Earth Entry Vehicle (EEV) that will impact without a parachute. EEVOs are designed to return materials from asteroids, comets, or planets for laboratory analysis on Earth. The EEV concept uses an energy absorbing cellular structure designed to contain and limit the acceleration of space exploration samples during Earth impact. The spherical shaped cellular structure is composed of solid hexagonal and pentagonal foam-filled cells with hybrid graphite-epoxy/Kevlar cell walls. Space samples fit inside a smaller sphere at the center of the EEVOs cellular structure. Pre-test analytical predictions were compared with the test results from a bungee accelerator. The model used to represent the foam and the proper failure criteria for the cell walls were critical in predicting the impact loads of the cellular structure. It was determined that a FOAM1 model for the foam and a 20% failure strain criteria for the cell walls gave an accurate prediction of the acceleration pulse for cellular impact.

Fasanella, Edwin L.; Billings, Marcus D.

2001-01-01

177

Examining the Impact of Audio Presentation on Tests of Reading Comprehension  

Microsoft Academic Search

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

Cara Cahalan Laitusis

2010-01-01

178

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

PubMed

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

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

2013-07-01

179

Scale-model turbine-missile-casing impact tests. Final report. [PWR; BWR  

SciTech Connect

Three 1/5-scale model turbine missile impact experiments are described in this report. These experiments were performed by SRI in support of the EPRI program to provide bench mark data for assessing turbine missile effects in nuclear plant design. The objective of the SRI experiments was to demonstrate the applicability of scaling in turbine missile impact of steel casing structures by comparing the results of the 1/5-scale tests with comparable full-scale tests performed by Sandia Laboratories. In the scale model experiments, geometric scaling was used where dimensions are reduced by the scale factor while materials, stresses, strains, and velocities remain the same as in the prototype. An explosive launcher was developed to accelerate the 1/5-scale models of a turbine missile to the desired impact velocities. The results of the scale model experiments agreed well with the results of the full-scale experiments and were sufficient to demonstrate scalability.

Romander, C.M.; Florence, A.L.

1983-01-01

180

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

SciTech Connect

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

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

1998-08-17

181

A Protocol System for Testing Biohazardous Materials in an Impact Biomechanics Research Facility  

Microsoft Academic Search

This article presents a protocol system, comprised of a review process and a series of checklists, that was developed for testing cadaveric tissue in an impact biomechanics research facility. The use of cadaveric tissue may expose personnel to bloodborne pathogens including HIV and hepatitis B, which have been shown to remain virulent in a cadaver for several weeks after death.

Stefan M. Duma; Rodney W. Rudd; Jeff R. Crandall

1999-01-01

182

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

Microsoft Academic Search

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

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

2009-01-01

183

Legal Challenges to High-Stakes Testing: A Case of Disparate Impact in Michigan?  

E-print Network

Legal Challenges to High-Stakes Testing: A Case of Disparate Impact in Michigan? Paper Presented University of Michigan School of Education 610 East University, 2108D SEB Ann Arbor, MI 48109-1259 734 of Higher and Postsecondary Education University of Michigan School of Education 610 East University, 2117

Heller, Don

184

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

ERIC Educational Resources Information Center

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…

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

2013-01-01

185

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

Code of Federal Regulations, 2013 CFR

...properties for service of 0 °F and below. 54.05-20 Section 54...properties for service of 0 °F and below. (a) Test energy...one specimen in a set may be below the required average and the value of that specimen must be above the minimum impact value...

2013-10-01

186

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

Code of Federal Regulations, 2012 CFR

...properties for service of 0 °F and below. 54.05-20 Section 54...properties for service of 0 °F and below. (a) Test energy...one specimen in a set may be below the required average and the value of that specimen must be above the minimum impact value...

2012-10-01

187

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

Code of Federal Regulations, 2010 CFR

...properties for service of 0 °F and below. 54.05-20 Section 54...properties for service of 0 °F and below. (a) Test energy...one specimen in a set may be below the required average and the value of that specimen must be above the minimum impact value...

2010-10-01

188

The Impact of the 2004 Hurricanes on Florida Comprehensive Assessment Test Scores: Implications for School Counselors  

ERIC Educational Resources Information Center

What is the impact of natural disasters on students' statewide assessment scores? To answer this question, Florida Comprehensive Assessment Test (FCAT) scores of 55,881 students in grades 4 through 10 were analyzed to determine if there were significant decreases after the 2004 hurricanes. Results reveal that there was statistical but no practical…

Baggerly, Jennifer; Ferretti, Larissa K.

2008-01-01

189

The Impact of Cognitive Testing on the Welfare of Group Housed Primates  

PubMed Central

Providing cognitive challenges to zoo-housed animals may provide enriching effects and subsequently enhance their welfare. Primates may benefit most from such challenges as they often face complex problems in their natural environment and can be observed to seek problem solving opportunities in captivity. However, the extent to which welfare benefits can be achieved through programmes developed primarily for cognitive research is unknown. We tested the impact of voluntary participation cognitive testing on the welfare of a socially housed group of crested macaques (Macaca nigra) at the Macaque Study Centre (Marwell Zoo). First, we compared the rate of self-directed and social behaviours on testing and non-testing days, and between conditions within testing days. Minimal differences in behaviour were found when comparing testing and non-testing days, suggesting that there was no negative impact on welfare as a result of cognitive testing. Lipsmacking behaviours were found to increase and aggressive interaction was found to decrease in the group as a result of testing. Second, social network analysis was used to assess the effect of testing on associations and interactions between individuals. The social networks showed that testing subjects increased their association with others during testing days. One interpretation of this finding could be that providing socially housed primates with an opportunity for individuals to separate from the group for short periods could help mimic natural patterns of sub-group formation and reunion in captivity. The findings suggest, therefore, that the welfare of captive primates can be improved through the use of cognitive testing in zoo environments. PMID:24223146

Whitehouse, Jamie; Micheletta, Jérôme; Powell, Lauren E.; Bordier, Celia; Waller, Bridget M.

2013-01-01

190

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

SciTech Connect

The two-dimensional Steven impact test has been developed to be reproducible and amenable to computer modeling. This test has a hemispherical projectile traveling at tens of m/s impacting a metal cased explosive target. To assist in the understanding of this safety test, two-dimensional shock wave gauge techniques were used to measure the pressures of a few kilobars and times of reactions less than a millisecond. This work is in accord with a long-term goal to develop two-dimensional shock diagnostic techniques that are more than just time of arrival indicators. Experiments were performed where explosives were impacted at levels below shock initiation levels but caused low level reactions. Carbon foil and carbon resistor pressure gauges were used to measure pressures and time of events. The carbon resistor gauges indicate a late time low level reaction at 350 {micro}s after impact of the hemispherical projectile creating 0.5-6 kb peak shocks at the center of PBX 9501 (HMX/Estane/BDNPA-F; 95/2.5/2.5 wt %) explosive discs. The Steven test calculations are based on an ignition and growth criteria and found that the low level reaction occurs at 335 {micro}s, which is in good agreement with the experimental data. Some additional experiments simulating the Steven impact test were done on a gas gun with carbon foil and constantan strain gauges in a PMMA target. Hydrodynamic calculations can be used to evaluate the gauge performance in these experiments and check the lateral strain measurements.

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

2000-10-10

191

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

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

192

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

NASA Technical Reports Server (NTRS)

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

Vassilakos, Gregory J.

2014-01-01

193

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

194

LX-04 VIOLENCE MEASUREMENTS- STEVEN TESTS IMPACTED BY PROJECTILES SHOT FROM A HOWITZER GUN  

SciTech Connect

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, acoustic microphones, and high-speed photography characterized the level of high explosive reaction violence. A detonation in this velocity range was not observed and when comparing these results (and the Susan test results) with that of other HMX based explosives, LX-04 has a more gradual reaction violence slope as the impact velocity increases. The high binder content (15%) of the LX-04 explosive is believed to be the key factor to the lower level of violence.

Chidester, S K; Vandersall, K S; Switzer, L L; Tarver, C M

2005-07-18

195

Dust Impact Monitor (DIM) onboard Rosetta/Philae: Tests with ice particles as comet analog materials  

NASA Astrophysics Data System (ADS)

In 2014 the European Space Agency's spacecraft Rosetta will encounter the short-period comet 67P/Churyumov-Gerasimenko. Rosetta carries the lander spacecraft Philae on board which will attempt to land on the comet's nucleus. Amongst Philae's instruments, the Dust Impact Monitor (DIM) using piezoelectric sensors is aimed at measuring the physical properties (size and impact speed) of the millimetric and submillimetric dust and ice particles that move near the surface of comet 67P. Given that DIM has three orthogonal sensor sides (with about 70 cm2) total area), it will also be able to collect dynamical data, like an estimation of the particle flux in three dimension, that will help to derive daily and secular variations in the surface activity. We show the results of a series of calibration experiments with the goal to extend the performance tests of DIM. We tested DIM under particle impacts of densities similar to and larger than that of water ice (0.92-7.80 g/cm3) and at speeds from 0.3 to 1.9 m/s. Then, we performed experiments with spherical water ice particles between -40 °C and -20 °C. Finally, we measured the coefficient of restitution (COR) of the impacting particles. These data show that there is a loss mechanism in the impact which is caused by plastic deformation in the contact zones of both the impinging particle and the PZT sensor.

Flandes, Alberto; Krüger, Harald; Loose, Alexander; Albin, Thomas; Arnold, Walter

2014-09-01

196

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

197

ACTUAL WASTE TESTING OF GYCOLATE IMPACTS ON THE SRS TANK FARM  

SciTech Connect

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

Martino, C.

2014-05-28

198

The impact of neurodynamic testing on the perception of experimentally induced muscle pain.  

PubMed

Neurodynamic tests such as the straight leg raising (SLR) and slump test are frequently used for assessment of mechanosensitivity of neural tissues. However, there is ongoing debate in the literature regarding the contributions of neural and non-neural tissues to the elicited symptoms because many structures are affected by these tests. Sensitizing manoeuvres are limb or spinal movements added to neurodynamic tests, which aim to identify the origin of the symptoms by preferentially loading or unloading neural structures. A prerequisite for the use of sensitizing manoeuvres to identify neural involvement is that the addition of sensitizing manoeuvres has no impact on pain perception when the origin of the pain is non-neural. In this study, experimental muscle pain was induced by injection of hypertonic saline in tibialis anterior or soleus in 25 asymptomatic, naive volunteers. A first experiment investigated the impact of hip adduction, abduction, medial and lateral rotation in the SLR position. In a second experiment, the different stages of the slump test were examined. The intensity and area of experimentally induced muscle pain did not increase when sensitizing manoeuvres were added to the SLR or throughout the successive stages of the slump test. The findings of this study lend support to the validity of the use of sensitizing manoeuvres during neurodynamic testing. PMID:15681269

Coppieters, Michel W; Kurz, Kimberly; Mortensen, Thor Einar; Richards, Nicola L; Skaret, Ingrid A; McLaughlin, Laurie M; Hodges, Paul W

2005-02-01

199

Technical basis for flawed cylinder test specification to assure adequate fracture resistance of ISO high strength steel cylinder  

SciTech Connect

High pressure industrial gases (such as oxygen, nitrogen, argon, hydrogen, etc.) are stored and transported in portable cylinders. ISO TC58 SC3 has developed a draft specification 9809 for design and fabrication of high pressure cylinders with maximum tensile strength limitation of 1,100 N/mm{sup 2}. In order to extend the ISO 9809 rules for higher than 1,100 N/mm{sup 2} strength level cylinders, a working group WG14 was formed in 1989 to develop new rules to assure adequate fracture resistance. In 1994, WG14 recommended a simple, but unique flawed cylinder test method for design qualification of the cylinder and acceptance criteria to assure adequate fracture resistance. WG14 also recommended Charpy-V-Notch impact tests to control the required fracture resistance on production cylinders. This paper presents the technical basis that was employed in developing the flawed cylinder test method and acceptance criteria. The specification was developed for seamless steel cylinders having actual strength in the range of 1,100 to 1,400 N/mm{sup 2} and cylindrical section wall thickness in the range of 3mm to 10mm. Flawed cylinder tests were conducted on several hundred cylinders of varying sizes and strength levels. The specification requires to demonstrate LEAK-BEFORE-BREAK performance of the cylinder having flaw length equal to 1.6(O.D. {times} t{sub design}){sup 0.5} at failure pressure = (t{sub design}/t{sub actual}) {times} Design Pressure.

Rana, M.D. [Praxair, Inc., Tonawanda, NY (United States). Process and Systems R and D; Smith, J.H. [National Inst. of Standards and Technology, Gaithersburg, MD (United States). Metallurgy Div.; Tribolet, R.O.

1996-12-01

200

MoSi2-Base Hybrid Composite Passed Engine Test  

NASA Technical Reports Server (NTRS)

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

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

1998-01-01

201

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

NASA Technical Reports Server (NTRS)

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

Duffy, Kirsten; Mehmed, Oral

2003-01-01

202

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

NASA Technical Reports Server (NTRS)

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

Puthoff, R. L.

1972-01-01

203

Modeling the Impact of Test Anxiety and Test Familiarity on the Criterion-Related Validity of Cognitive Ability Tests  

ERIC Educational Resources Information Center

The assessment of cognitive abilities, whether it is for purposes of basic research or applied decision making, is potentially susceptible to both facilitating and debilitating influences. However, relatively little research has examined the degree to which these factors might moderate the criterion-related validity of cognitive ability tests. To…

Reeve, Charlie L.; Heggestad, Eric D.; Lievens, Filip

2009-01-01

204

Hypervelocity impact testing of the Space Station utility distribution system carrier  

NASA Technical Reports Server (NTRS)

A two-phase, joint JSC and McDonnell Douglas Aerospace-Huntington Beach hypervelocity impact (HVI) test program was initiated to develop an improved understanding of how meteoroid and orbital debris (M/OD) impacts affect the Space Station Freedom (SSF) avionic and fluid lines routed in the Utility Distribution System (UDS) carrier. This report documents the first phase of the test program which covers nonpowered avionic line segment and pressurized fluid line segment HVI testing. From these tests, a better estimation of avionic line failures is approximately 15 failures per year and could very well drop to around 1 or 2 avionic line failures per year (depending upon the results of the second phase testing of the powered avionic line at White Sands). For the fluid lines, the initial McDonnell Douglas analysis calculated 1 to 2 line failures over a 30 year period. The data obtained from these tests indicate the number of predicted fluid line failures increased slightly to as many as 3 in the first 10 years and up to 15 for the entire 30 year life of SSF.

Lazaroff, Scott

1993-01-01

205

Testing of a diesel-powered impact cutting head for hard-rock mining  

SciTech Connect

This book reports on the performance of a novel prototype kerf-cutting impact mining machine that was evaluated under a cooperative agreement between the U.S. Bureau of Mines and RAMEX Systems, Bellevue, WA, while operating under conditions typical of normal tunnel entry development. Selected operating parameters were monitored concurrently to determine baseline operating conditions and to study relationships between operating parameters. Using the data obtained, the specific energy requirements of the impact mining machine were calculated and compared to specific energy requirements of tunnel boring machines cutting in rock having similar hardness. Tests results indicate that the kerf-cutting impact mining machine can provide a mechanical means for mining very hard rock that cannot be effectively mined using commercially available mechanical excavators.

Not Available

1991-01-01

206

The WRAIR projectile concussive impact model of mild traumatic brain injury: re-design, testing and preclinical validation.  

PubMed

The WRAIR projectile concussive impact (PCI) model was developed for preclinical study of concussion. It represents a truly non-invasive closed-head injury caused by a blunt impact. The original design, however, has several drawbacks that limit the manipulation of injury parameters. The present study describes engineering advancements made to the PCI injury model including helmet material testing, projectile impact energy/head kinematics and impact location. Material testing indicated that among the tested materials, 'fiber-glass/carbon' had the lowest elastic modulus and yield stress for providing an relative high percentage of load transfer from the projectile impact, resulting in significant hippocampal astrocyte activation. Impact energy testing of small projectiles, ranging in shape and size, showed the steel sphere produced the highest impact energy and the most consistent impact characteristics. Additional tests confirmed the steel sphere produced linear and rotational motions on the rat's head while remaining within a range that meets the criteria for mTBI. Finally, impact location testing results showed that PCI targeted at the temporoparietal surface of the rat head produced the most prominent gait abnormalities. Using the parameters defined above, pilot studies were conducted to provide initial validation of the PCI model demonstrating quantifiable and significant increases in righting reflex recovery time, axonal damage and astrocyte activation following single and multiple concussions. PMID:24756867

Leung, Lai Yee; Larimore, Zachary; Holmes, Larry; Cartagena, Casandra; Mountney, Andrea; Deng-Bryant, Ying; Schmid, Kara; Shear, Deborah; Tortella, Frank

2014-08-01

207

Characterization, testing and constitutive modelling of an impact-modified polypropylene  

NASA Astrophysics Data System (ADS)

Impact modified polypropylenes (or TPOs) are polymer blends of isotactic polypropylene (iPP), ethylene-propylene-diene monomer elastomer (EPDM), and high density polyethylene (HDPE). Currently, TPOs are extensively used in impact applications, such as car bumpers. However, the design process of TPO parts for impact applications is still an expensive, trial-and-error procedure. In this project, we aim to develop a material model with specific physical bases to represent a TPO material, so that TPO part design can be effective and efficient. In order to achieve our objective, morphology characterization and mechanical testing have been conducted to examine the intrinsic mechanisms of TPO. Tests were conducted over a broad range of strain rates using both a servohydraulic apparatus and an Aluminum split Hopkinson pressure bar. The TPO system we examined is multi-phasic in which an EPDM and HDPE blend forms the minor domain, distributed in the iPP matrix. The large deformation TPO response includes strain rate dependent initial stiffness; temperature, deformation state and strain rate dependent yield; temperature and deformation state dependent strain hardening. Its response is not unlike that of glassy polymers in many ways, owing to the flexibility of the iPP matrix, however the TPO shows a moderate strain hardening rate and little strain recovery upon unloading. A three-dimensional, four-element constitutive model has been developed for this TPO. The model includes rate dependent stiffness, rate and temperature dependent yield, temperature dependent strain hardening, and crystallographic slip. The model has been examined to be robust over a wide range of strain rates from quasi-static to impact, and predictive of different deformation states, such as uniaxial compression and plane strain compression. The model has been shown to capture the post-yield thermal softening and apparent lack of post-yield strain hardening at impact test conditions.

Wang, Yan

2002-01-01

208

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

SciTech Connect

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

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

2002-06-28

209

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

210

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

SciTech Connect

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

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

2005-09-26

211

Normalizing and scaling of data to derive human response corridors from impact tests.  

PubMed

It is well known that variability is inherent in any biological experiment. Human cadavers (Post-Mortem Human Subjects, PMHS) are routinely used to determine responses to impact loading for crashworthiness applications including civilian (motor vehicle) and military environments. It is important to transform measured variables from PMHS tests (accelerations, forces and deflections) to a standard or reference population, termed normalization. The transformation process should account for inter-specimen variations with some underlying assumptions used during normalization. Scaling is a process by which normalized responses are converted from one standard to another (example, mid-size adult male to large-male and small-size female adults, and to pediatric populations). These responses are used to derive corridors to assess the biofidelity of anthropomorphic test devices (crash dummies) used to predict injury in impact environments and design injury mitigating devices. This survey examines the pros and cons of different approaches for obtaining normalized and scaled responses and corridors used in biomechanical studies for over four decades. Specifically, the equal-stress equal-velocity and impulse-momentum methods along with their variations are discussed in this review. Methods ranging from subjective to quasi-static loading to different approaches are discussed for deriving temporal mean and plus minus one standard deviation human corridors of time-varying fundamental responses and cross variables (e.g., force-deflection). The survey offers some insights into the potential efficacy of these approaches with examples from recent impact tests and concludes with recommendations for future studies. The importance of considering various parameters during the experimental design of human impact tests is stressed. PMID:24726322

Yoganandan, Narayan; Arun, Mike W J; Pintar, Frank A

2014-06-01

212

DWPF (Defense Waste Processing Facility) canister impact testing and analyses for the Transportation Technology Center  

SciTech Connect

A legal weight truck cask design has been developed for the US Department of Energy by GA Technologies, Inc. The cask will be used to transport defense high-level waste canisters produced by the Defense Waste Processing Facility (DWPF) at the Savannah River Plant. The development of the cask required the collection of impact data for the DWPF canisters. The Materials Characterization Center (MCC) performed this work under the guidance of the Transportation Technology Center (TTC) at Sandia National Laboratories. Two full-scale DWPF canisters filled with nonradioactive borosilicate glass were impacted under ''normal'' and ''hypothetical'' accident conditions. Two canisters, supplied by the DWPF, were tested. Each canister was vertically dropped on the bottom end from a height of either 0.3 m or 9.1 m (for normal or hypothetical accident conditions, respectively). The structural integrity of each canister was then examined using helium leak and dye penetrant testing. The canisters' diameters and heights, which had been previously measured, were then remeasured to determine how the canister dimensions had changed. Following structural integrity testing, the canisters were flaw leak tested. For transportation flaw leak testing, four holes were fabricated into the shell of canister A-27 (0.3 m drop height). The canister was then transported a total distance of 2069 miles. During transport, the waste form material that fell from each flaw was collected to determine the amount of size distribution of each flaw release. 2 refs., 8 figs., 12 tabs.

Farnsworth, R.K.; Mishima, J.

1988-12-01

213

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

214

Uniform Foam Crush Testing for Multi-Mission Earth Entry Vehicle Impact Attenuation  

NASA Technical Reports Server (NTRS)

Multi-Mission Earth Entry Vehicles (MMEEVs) are blunt-body vehicles designed with the purpose of transporting payloads from outer space to the surface of the Earth. To achieve high-reliability and minimum weight, MMEEVs avoid use of limited-reliability systems, such as parachutes and retro-rockets, instead using built-in impact attenuators to absorb energy remaining at impact to meet landing loads requirements. The Multi-Mission Systems Analysis for Planetary Entry (M-SAPE) parametric design tool is used to facilitate the design of MMEEVs and develop the trade space. Testing was conducted to characterize the material properties of several candidate impact foam attenuators to enhance M-SAPE analysis. In the current effort, four different Rohacell foams are tested at three different, uniform, strain rates (approximately 0.17, approximately 100, approximately 13,600%/s). The primary data analysis method uses a global data smoothing technique in the frequency domain to remove noise and system natural frequencies. The results from the data indicate that the filter and smoothing technique are successful in identifying the foam crush event and removing aberrations. The effect of strain rate increases with increasing foam density. The 71-WF-HT foam may support Mars Sample Return requirements. Several recommendations to improve the drop tower test technique are identified.

Patterson, Byron W.; Glaab, Louis J.

2012-01-01

215

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

NASA Technical Reports Server (NTRS)

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

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

2006-01-01

216

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

USGS Publications Warehouse

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

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

2006-01-01

217

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

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

218

Impact  

NASA Technical Reports Server (NTRS)

Impact, emergency escape and crash survival protection are studied. Accleration, the G system of units, data interpretation, and human tolerance limits are summarized, along with physiological and biochemical response to impact. Biomechanical factors of impact are also cited.

Snyder, R. G.

1973-01-01

219

A 640 foot per second impact test of a two foot diameter model nuclear reactor containment system without fracture  

NASA Technical Reports Server (NTRS)

An impact test was conducted on an 1142 pound 2 foot diameter sphere model. The purpose of this test was to determine the feasibility of containing the fission products of a mobile reactor in an impact. The model simulated the reactor core, energy absorbing gamma shielding, neutron shielding and the containment vessel. It was impacted against an 18,000 pound reinforced concrete block. The model was significantly deformed and the concrete block demolished. No leaks were detected nor cracks observed in the model after impact.

Puthoff, R. L.

1971-01-01

220

Multi-Dimensional Validation Impact Tests on PZT 95/5 and ALOX  

NASA Astrophysics Data System (ADS)

Multi-dimensional impact tests were conducted on the ferroelectric ceramic PZT 95/5 and alumina-loaded epoxy (ALOX) encapsulants, with the purpose of providing benchmarks for material models in the ALEGRA wavecode. Diagnostics used included line-imaging VISAR (velocity interferometry), a key diagnostic for such tests. Results from four tests conducted with ALOX cylinders impacted by nonplanar copper projectiles were compared with ALEGRA simulations. The simulation produced approximately correct attenuations and divergence, but somewhat higher wave velocities. Several sets of tests conducted using PZT rods (length:diameter ratio = 5:1) encapsulated in ALOX, and diagnosed with line-imaging and point VISAR, were modeled as well. Significant improvement in wave arrival times and waveforms agreement for the two-material multi-dimensional experiments was achieved by simultaneous multiple parameter optimization on multiple one-dimensional experiments. Additionally, a variable friction interface was studied in these calculations. We conclude further parameter optimization is required for both material models.

Furnish, M. D.; Robbins, J.; Trott, W. M.; Chhabildas, L. C.; Lawrence, R. J.; Montgomery, S. T.

2002-07-01

221

Thermal Impact on Damaged Boom Clay and Opalinus Clay: Permeameter and Isostatic Tests with ?CT Scanning  

NASA Astrophysics Data System (ADS)

Within the framework of the TIMODAZ project, permeameter tests and isostatic tests were performed on Boom Clay and Opalinus Clay in order to assess the impact of temperature, pore water composition, and confining stress on the sealing of damaged samples of Boom Clay and Opalinus Clay. A microfocus X-ray computed tomography technique was used to visualize the evolution of the sealing process. Compared to the fast sealing of Boom Clay, the sealing of Opalinus Clay was much slower. The heating showed a significant, favorable impact on the sealing behavior of Opalinus Clay under permeameter test conditions, while the sealing behavior of Boom Clay appeared to be unaffected. Tests performed under isostatic conditions did not reveal a significant influence of a heating-cooling cycle on the sealing behavior of these clays. The reappearance of the fractures or holes in the samples after dismantling confirms earlier observations which showed that after sealing, the original mechanical properties are not recovered. In other words, a heating cycle does not seem to induce healing.

Chen, G. J.; Maes, T.; Vandervoort, F.; Sillen, X.; Van Marcke, P.; Honty, M.; Dierick, M.; Vanderniepen, P.

2014-01-01

222

Evaluating cover depth of steel fiber reinforced concrete using impact-echo testing  

NASA Astrophysics Data System (ADS)

The purpose of this research is to estimate of the cover depth of steel fiber reinforced concrete using the impact-echo testing. In order to evaluate the security of the construction, usually need to estimate the cover depth of the reinforced concrete. At present, the examination technique of the cover depth of the reinforced concrete without the steel fiber is mainly applied in the magnetic and electrical methods, its rapid detection and good results. But the research of the reactive powder concrete be gradually progress, with the steel fiber concrete structure will be increased, if should still operate the examination with the magnetic and electrical methods, theoretically the steel fiber will have the interference to its electromagnetism field. Therefore, this research designs four kinds of reinforced concrete plate that include different steel fiber contents, to evaluate test results of estimate of the cover depth of the reinforcing bar. The results showed that: estimate of the cover depth of steel fiber reinforced concrete reinforcing bar using the impact-echo testing, the variety of the steel fiber content does not have much influence, the test measurement error within ± 10%, and the most important source of uncertainty is the velocity of concrete.

Lin, Yu-Feng

2014-04-01

223

Impact dynamics research facility for full-scale aircraft crash testing  

NASA Technical Reports Server (NTRS)

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 desired flight paths and velocities. Flight paths up to -60 deg and aircraft velocities along the flight paths up to about 27.0 m/s can be obtained with a combination of swing-cable lengths and release heights made available by a large gantry. Seven twin engine, 2721-kg aircraft were successfully crash tested at the facility, and all systems functioned properly. Acquisition of data from signals generated by accelerometers on board the aircraft and from external and onboard camera coverage was successful in spite of the amount of damage which occurred during each crash. Test parameters at the IDRF are controllable with flight path angles accurate within 8 percent, aircraft velocity accurate within 6 percent, pitch angles accurate to 4.25 deg, and roll and yaw angles acceptable under wind velocities up to 4.5 m/s.

Vaughan, V. L. J.; Alfaro-Bou, E.

1976-01-01

224

Experimental and numerical analysis of Izod impact test of cortical bone tissue  

NASA Astrophysics Data System (ADS)

Bones can only sustain loads until a certain limit, beyond which they fail. Usually, the reasons for bone fracture are traumatic falls, sports injuries, and engagement in transport or industrial accidents. A proper treatment of bones and prevention of their fracture can be supported by in-depth understanding of deformation and fracture behavior of this tissue in such dynamic events. In this paper, a combination of experimental and numerical analysis was carried out in order to comprehend the fracture behavior of cortical bone tissue. Experimental tests were performed to study the transient dynamic behavior of cortical bone tissue under impact bending loading. The variability of absorbed energy for different cortex positions and notch depths was studied using Izod impact tests. Also, Extended Finite-Element Method implemented into the commercial finite-element software Abaqus was used to simulate the crack initiation and growth processes in a cantilever beam of cortical bone exposed to impact loading using the Izod loading scheme. The simulation results show a good agreement with the experimental data.

Abdel-Wahab, A. A.; Silberschmidt, V. V.

2012-05-01

225

Threshold Studies of Heated HMX-Based Energetic Material Targets Using the Steven Impact Test  

SciTech Connect

Impact tests performed at low velocity on heated energetic material samples are of interest when considering the situation of energetic materials involved in a fire. To determine heated reaction thresholds, Steven Test targets containing PBX 9404 or LX-04 samples heated to the range of 150-170 C were impacted at velocities up to 150 m/s by two different projectile head geometries. Comparing these measured thresholds to ambient temperature thresholds revealed that the heated LX-04 thresholds were considerably higher than ambient, whereas the heated PBX 9404 thresholds were only slightly higher than the ambient temperature thresholds. The violence of reaction level of the PBX 9404 was considerably higher than that of the LX-04 as measured with four overpressure gauges. The varying results in these samples with different HMX/binder configurations indicate that friction plays a dominant role in reaction ignition during impact. This work outlines the experimental details, compares the thresholds and violence levels of the heated and ambient temperature experiments, and discusses the dominant mechanisms of the measured thresholds.

Switzer, L L; Vandersall, K S; Chidester, S K; Greenwood, D W; Tarver, C M

2003-07-01

226

Hypervelocity impact testing of advanced materials and structures for micrometeoroid and orbital debris shielding  

NASA Astrophysics Data System (ADS)

A series of 66 hypervelocity impact experiments have been performed to assess the potential of various materials (aluminium, titanium, copper, stainless steel, nickel, nickel/chromium, reticulated vitreous carbon, silver, ceramic, aramid, ceramic glass, and carbon fibre) and structures (monolithic plates, open-cell foam, flexible fabrics, rigid meshes) for micrometeoroid and orbital debris (MMOD) shielding. Arranged in various single-, double-, and triple-bumper configurations, screening tests were performed with 0.3175 cm diameter Al2017-T4 spherical projectiles at nominally 6.8 km/s and normal incidence. The top performing shields were identified through target damage assessments and their respective weight. The top performing candidate shield at the screening test condition was found to be a double-bumper configuration with a 0.25 mm thick Al3003 outer bumper, 6.35 mm thick 40 PPI aluminium foam inner bumper, and 1.016 mm thick Al2024-T3 rear wall (equal spacing between bumpers and rear wall). In general, double-bumper candidates with aluminium plate outer bumpers and foam inner bumpers were consistently found to be amongst the top performers. For this impact condition, potential weight savings of at least 47% over conventional all-aluminium Whipple shields are possible by utilizing the investigated materials and structures. The results of this study identify materials and structures of interest for further, more in-depth, impact investigations.

Ryan, Shannon; Christiansen, Eric L.

2013-02-01

227

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

228

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

ERIC Educational Resources Information Center

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

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

2013-01-01

229

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

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

230

Test and Analysis Correlation of Form Impact onto Space Shuttle Wing Leading Edge RCC Panel 8  

NASA Technical Reports Server (NTRS)

Soon after the Columbia Accident Investigation Board (CAIB) began their study of the space shuttle Columbia accident, "physics-based" analyses using LS-DYNA were applied to characterize the expected damage to the Reinforced Carbon-Carbon (RCC) leading edge from high-speed foam impacts. Forensic evidence quickly led CAIB investigators to concentrate on the left wing leading edge RCC panels. This paper will concentrate on the test of the left-wing RCC panel 8 conducted at Southwest Research Institute (SwRI) and the correlation with an LS-DYNA analysis. The successful correlation of the LS-DYNA model has resulted in the use of LS-DYNA as a predictive tool for characterizing the threshold of damage for impacts of various debris such as foam, ice, and ablators onto the RCC leading edge for shuttle return-to-flight.

Fasanella, Edwin L.; Lyle, Karen H.; Gabrys, Jonathan; Melis, Matthew; Carney, Kelly

2004-01-01

231

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. PMID:21811306

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

2011-01-01

232

Tests to evaluate the ecological impact of treated ballast water on three Chinese marine species  

NASA Astrophysics Data System (ADS)

Ballast water has been a topic of concern for some time because of its potential to introduce invasive species to new habitats. To comply with the International Convention for the Control and Management of Ships' Ballast Water and Sediments, members of the International Maritime Organization (IMO) must equip their ships with on-board treatment systems to eliminate organism release with ballast water. There are many challenges associated with the implementation of this IMO guideline, one of which is the selection of species for testing the ecological impacts of the treated ballast water. In the United States, ballast water toxicity test methods have been defined by the United States Environmental Protection Agency. However, the test methods had not been finalized in China until the toxicity test methods for ballast water were established in 2008. The Chinese methods have been based on species from three trophic levels: Skeletonema costatum, Neomysis awatschensis, and Ctenogobius gymnauchen. All three species live in broad estuarine and open sea areas of China; they are sensitive to reference toxicants and acclimatize easily to different conditions. In this paper, the biological characteristics, test processes and statistical analysis methods are presented for the three species. Results indicate that the methods for evaluating these three organisms can be included in the ecological toxicity tests for treated ballast water in China.

Zhang, Yanan; Wang, Zixi; Cai, Leiming; Cai, Xiang; Sun, Wenjun; Ma, Liqing

2014-09-01

233

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

234

Damage Detection and Impact Testing on Laminated and Sandwich Composite Panels  

NASA Technical Reports Server (NTRS)

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

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

1998-01-01

235

Design of Spacecraft Missions to Test Kinetic Impact for Asteroid Deflection  

NASA Technical Reports Server (NTRS)

There are currently over 8,000 known near-Earth asteroids (NEAs), and more are being discovered on a continual basis. More than 1,200 of these are classified as Potentially Hazardous Asteroids (PHAs) because their Minimum Orbit Intersection Distance (MOID) with Earth's orbit is <= 0.05 AU and their estimated diameters are >= 150 m. To date, 178 Earth impact structures have been discovered, indicating that our planet has previously been struck with devastating force by NEAs and will be struck again. Such collisions are aperiodic events and can occur at any time. A variety of techniques have been proposed to defend our planet from NEA impacts by deflecting the incoming asteroid. However, none of these techniques have been tested. Unless rigorous testing is conducted to produce reliable asteroid deflection systems, we will be forced to deploy completely untested -- and therefore unreliable -- deflection missions when a sizable asteroid on a collision course with Earth is discovered. Such missions will have a high probability of failure. We propose to address this problem with a campaign of deflection technology test missions deployed to harmless NEAs. The objective of these missions is to safely evaluate and refine the mission concepts and asteroid deflection system designs. Our current research focuses on the kinetic impactor, one of the simplest proposed asteroid deflection techniques in which a spacecraft is sent to collide with an asteroid at high relative velocity. By deploying test missions in the near future, we can characterize the performance of this deflection technique and resolve any problems inherent to its execution before needing to rely upon it during a true emergency. In this paper we present the methodology and results of our survey, including lists of NEAs for which safe and effective kinetic impactor test missions may be conducted within the next decade. Full mission designs are also presented for the NEAs which offer the best mission opportunities.

Hernandez, Sonia; Barbee, Brent W.

2011-01-01

236

Water impact test of aft skirt end ring, and mid ring segments of the Space Shuttle Solid Rocket Booster  

NASA Technical Reports Server (NTRS)

The results of water impact loads tests using aft skirt end ring, and mid ring segments of the Space Shuttle Solid Rocket Booster (SRB) are examined. Dynamic structural response data is developed and an evaluation of the model in various configurations is presented. Impact velocities are determined for the SRB with the larger main chute system. Various failure modes are also investigated.

1983-01-01

237

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

238

THE USE OF ENVIRONMENTAL FATE AND EFFECTS TESTING IN THE EVALUATION OF ENVIRONMENTAL IMPACT FOR CHEMICAL PRODUCT MANAGEMENT AND CONTROL  

Microsoft Academic Search

The development of ecotoxicological tests to determine environmental hazards associated with chemical substances has become increasingly important. This increased interest in the use of biological endpoints to assess the impact of substances was mainly driven by society's demand for risk related information. Over the last decade there has been a shift of focus from the impact of waste and effluents

RMC Albertus; LG Phillips; JL Slabbert; EA Venter

239

Testing the impact on natural risks' awareness of visual communication through an exhibition  

NASA Astrophysics Data System (ADS)

The need to communicate about natural disasters in order to improve the awareness of communities at risk is not a matter for debate anymore. However, communication can be implemented using different media and tools, and their effectiveness may be difficult to grasp. Current research on the topic is usually focused on assessing whether communication practices meet users' needs, whereas impact assessment is mostly left out. It can be explained by difficulties arising from (1) the definition of the impact to measure, i.e. awareness, and the appropriate indicators to measure it and its variations, and (2) the implementation of a research design that allows assessing these impacts without bias. This research aims at both developing a methodology to measure risk awareness and to use it for testing the effectiveness of visual communication. The testing was conducted in the Ubaye Valley in France, an alpine area affected by multiple hazards, from December 2013 to mid-February 2014. The setting consisted of an exhibition in the public library of the main town, Barcelonnette. The main natural hazards of the study case (i.e. landslides, avalanches, flooding, debris flows and earthquakes), as well as structural and non-structural measures were presented to the general public using local examples of hazards events and mitigation. Various visualization tools were used: videos, Google earth map, interactive timeline, objects, mock-ups, technical devices as well as posters with pictures, drawings and graphs. In order to assess the effects of the exhibition on risk awareness, several groups of children and adults were submitted to a research design, consisting of 1) a pre-test, 2) the visit of the exhibition and 3) a post-test similar to the pre-test. Close-ended questions addressed the awareness indicators according to the literature, i.e. worry level, previous experiences with natural hazards events, exposure to awareness raising, ability to mitigate/respond/prepare, attitude to risk and demographics. In addition, the post-test included several satisfaction questions concerning the visual tools displayed in the exhibition. A statistical analysis of the changes between the pre- and post- tests allows to verify whether the exhibition has an impact on risk awareness or not. In order to deduce the attractiveness of each visual tool independently, the visitors' paths are tracked using RFID (Radio Frequency Identification) technique, from which their time spent around certain visuals can be assessed. These results also help to analyze the changes in risk awareness measured by the pre-test/post-test design. Direct observation of visitors' reactions and behaviors completed the methodology. This research hence helps to assess which visual tools are more suitable to communicate such topics not only to a community as a whole, but also to its sub-categories (e.g. adults vs. children, people with experience of natural disasters vs. people without). Moreover, it provides methodological improvements concerning effectiveness research in the field of risk communication. The first results of this research will be presented and discussed.

Charrière, Marie; Bogaard, Thom; Junier, Sandra; Malet, Jean-Philippe; Mostert, Erik

2014-05-01

240

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

241

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

242

Economic Impact of Tissue Testing and Treatments of Metastatic NSCLC in the Era of Personalized Medicine  

PubMed Central

A paradigm-shift in the management of non-small cell lung cancer (NSCLC) has resulted in many new therapies becoming available for patients with advanced disease. Stratification of treatment by histologic and molecular subtype is recommended to obtain the greatest clinical benefit for patients while minimizing adverse effects of treatment. However, these advances in diagnosis and treatment of NSCLC have come at a financial cost. This review highlights the economic impact of screening for molecular abnormalities and targeted treatment for advanced NSCLC. Major determinants of cost are drug acquisition and molecular testing. As technologies advance, molecular testing costs may reduce. However, we must collaborate with payers and manufacturers to ensure that high drug costs do not limit patient accessibility to potentially beneficial treatment. PMID:25295228

Graham, Donna M.; Leighl, Natasha B.

2014-01-01

243

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

SciTech Connect

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

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

2000-01-01

244

Charpy impact tests on martensitic/ferritic steels after irradiation in SINQ target-3  

NASA Astrophysics Data System (ADS)

Charpy impact tests were performed on martensitic/ferritic (MF) steels T91, F82H, Optifer-V and Optimax-A/-C irradiated in SINQ Target-3 up to 7.5 dpa and 500 appm He in a temperature range of 120-195 °C. Results demonstrate that for all the four kinds of steels, the ductile-to-brittle transition temperature (DBTT) increases with irradiation dose. The difference in the DBTT shifts (?DBTT) of the different steels is not significant after irradiation in the SINQ target. The ?DBTT data from the previous small punch (? DBTT SP) and the present Charpy impact (?DBTT CVN) tests can be correlated with the expression: ? DBTT SP = 0.4?DBTT CVN. All the ?DBTT data fall into a linear band when they are plotted versus helium concentration. The results indicate that helium effects on the embrittlement of MF steels are significant, particularly at higher concentrations. It suggests that MF steels may not be very suitable for applications at low temperatures in spallation irradiation environments where helium production is high.

Dai, Yong; Marmy, Pierre

2005-08-01

245

Simulating the Response of a Composite Honeycomb Energy Absorber. Part 2; Full-Scale Impact Testing  

NASA Technical Reports Server (NTRS)

NASA has sponsored research to evaluate an externally deployable composite honeycomb designed to attenuate loads in the event of a helicopter crash. The concept, designated the Deployable Energy Absorber (DEA), is an expandable Kevlar(Registered TradeMark) honeycomb. The DEA has a flexible hinge that allows the honeycomb to be stowed collapsed until needed during an emergency. Evaluation of the DEA began with material characterization of the Kevlar(Registered TradeMark)-129 fabric/epoxy, and ended with a full-scale crash test of a retrofitted MD-500 helicopter. During each evaluation phase, finite element models of the test articles were developed and simulations were performed using the dynamic finite element code, LS-DYNA(Registered TradeMark). The paper will focus on simulations of two full-scale impact tests involving the DEA, a mass-simulator and a full-scale crash of an instrumented MD-500 helicopter. Isotropic (MAT24) and composite (MAT58) material models, which were assigned to DEA shell elements, were compared. Based on simulations results, the MAT58 model showed better agreement with test.

Fasanella, Edwin L.; Annett, Martin S.; Jackson, Karen E.; Polanco, Michael A.

2012-01-01

246

Assessment of impacts at the advanced test reactor as a result of chemical releases at the Idaho Chemical Processing Plant  

Microsoft Academic Search

This report provides an assessment of potential impacts at the Advanced Test Reactor Facility (ATR) resulting from accidental chemical spill at the Idaho Chemical Processing Plant (ICPP). Spills postulated to occur at the Lincoln Blvd turnoff to ICPP were also evaluated. Peak and time weighted average concentrations were calculated for receptors at the ATR facility and the Test Reactor Area

Rood

1991-01-01

247

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

248

Testing the origin of high remanent magnetization in Vredefort impact structure  

NASA Astrophysics Data System (ADS)

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, 3, 4, 5]. It has been suggested that the source for elevated NRM values and hence elevated Q values (Koenigsberger’s ratio) would be related to impact event in a way where an ultra-small single-domain magnetite formed in a high pressure/temperature environment and crystallized along planar deformation features [2, 6, 3]. It has been further suggested that a plasma field produced from the impact event generated small-wavelength magnetic fields of high intensity which randomized the directions of remanent magnetization [4, 8]. Results of [5] contradict these findings. As, firstly, concentration of elevated Q values near the center of the structure was not observed, as should be if of impact origin, and, secondly, the elevated Q values were also seen in samples from the Johannesburg Dome (120 km from Vredefort dome). Moreover a correlation between hysteresis data and elevated Q values of the basement rocks was not observed, as would be expected if the ultra-fine particles in the PDFs solely were the carriers of the high Q values [5]. This seems to rule out the direct connection of elevated NRM to the shock event. In order to further study the origin of elevated NRM values we have tried to simulate impact shock with conventional explosives and to simulate lighting strikes with high voltage measurements. Ten Archean host rock samples (masses between 0.5 and 1.5 kg) with normal Q values (0.7-2) for Vredefort impact structure were exploded using the plastic explosive with explosive velocity of 8.2 km/s. Three out of ten samples were covered with cement before exploding. Six demagnetized Archean host rock samples originally with low Q values (0.9-2) were treated with high voltage equipment (Haefely Test, AG Switzerland; max: 1000 kV) in order to simulate lightning strikes. Three pulses (11.5 kA) were given to two and one pulse was given to four samples. Exploding did not increase NRM, susceptibility or Q values of the samples. However we are aware that this study is a small scale study and in case of the Vredefort the velocity of the projectile has been modelled to be ca. 20 km/s [7]. After high voltage treatment samples showed elevated Q and NRM values with relation to number of pulses. This study indicates that lightning strikes with multiple pulses could explain observed high Q values and random magnetization directions observed for Vredefort rocks. References: [1] Henkel & Reimold 1998. Tectonophysics 287, 1-20; [2] Hart et al. 1995. Geology, 23, 277-280; [3] Hart et al. 2000. Afr. J. Geol. 103, 151-155; [4] Carporzen et al. 2005. Nature 435, 198-201; [5] Salminen et al. 2009. Prec. Res. 168, 167-184; [6] Cloete et al. 1999. Mineral. Petrol. 137, 232-245; [7] Turtle & Pierazzo 1998. Meteorit. Planet. Sci. 33, 483-490. [8] Kletetscka 2010. Travaux Geophysiques XXXIX (2010), 40-41.

Salminen, J. M.; Pesonen, L. J.; Lahti, K.; Kannus, K.

2010-12-01

249

Flight test experience and controlled impact of a remotely piloted jet transport aircraft  

NASA Technical Reports Server (NTRS)

The Dryden Flight Research Center Facility of NASA Ames Research Center (Ames-Dryden) and the FAA conducted the controlled impact demonstration (CID) program using a large, four-engine, remotely piloted jet transport airplane. Closed-loop primary flight was controlled through the existing onboard PB-20D autopilot which had been modified for the CID program. Uplink commands were sent from a ground-based cockpit and digital computer in conjunction with an up-down telemetry link. These uplink commands were received aboard the airplane and transferred through uplink interface systems to the modified PB-20D autopilot. Both proportional and discrete commands were produced by the ground system. Prior to flight tests, extensive simulation was conducted during the development of ground-based digital control laws. The control laws included primary control, secondary control, and racetrack and final approach guidance. Extensive ground checks were performed on all remotely piloted systems; however, piloted flight tests were the primary method and validation of control law concepts developed from simulation. The design, development, and flight testing of control laws and systems required to accomplish the remotely piloted mission are discussed.

Horton, Timothy W.; Kempel, Robert W.

1988-01-01

250

Hypervelocity Impact Test Fragment Modeling: Modifications to the Fragment Rotation Analysis and Lightcurve Code  

NASA Technical Reports Server (NTRS)

Hypervelocity impact tests on test satellites are performed by members of the orbital debris scientific community in order to understand and typify the on-orbit collision breakup process. By analysis of these test satellite fragments, the fragment size and mass distributions are derived and incorporated into various orbital debris models. These same fragments are currently being put to new use using emerging technologies. Digital models of these fragments are created using a laser scanner. A group of computer programs referred to as the Fragment Rotation Analysis and Lightcurve code uses these digital representations in a multitude of ways that describe, measure, and model on-orbit fragments and fragment behavior. The Dynamic Rotation subroutine generates all of the possible reflected intensities from a scanned fragment as if it were observed to rotate dynamically while in orbit about the Earth. This calls an additional subroutine that graphically displays the intensities and the resulting frequency of those intensities as a range of solar phase angles in a Probability Density Function plot. This document reports the additions and modifications to the subset of the Fragment Rotation Analysis and Lightcurve concerned with the Dynamic Rotation and Probability Density Function plotting subroutines.

Gouge, Michael F.

2011-01-01

251

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

PubMed Central

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; Chenel, Marylore; Mentré, France

2009-01-01

252

The Impact of Data-Based Science Instruction on Standardized Test Performance  

NASA Astrophysics Data System (ADS)

Increased teacher accountability efforts have resulted in the use of data to improve student achievement. This study addressed teachers' inconsistent use of data-driven instruction in middle school science. Evidence of the impact of data-based instruction on student achievement and school and district practices has been well documented by researchers. In science, less information has been available on teachers' use of data for classroom instruction. Drawing on data-driven decision making theory, the purpose of this study was to examine whether data-based instruction impacted performance on the science Criterion Referenced Competency Test (CRCT) and to explore the factors that impeded its use by a purposeful sample of 12 science teachers at a data-driven school. The research questions addressed in this study included understanding: (a) the association between student performance on the science portion of the CRCT and data-driven instruction professional development, (b) middle school science teachers' perception of the usefulness of data, and (c) the factors that hindered the use of data for science instruction. This study employed a mixed methods sequential explanatory design. Data collected included 8th grade CRCT data, survey responses, and individual teacher interviews. A chi-square test revealed no improvement in the CRCT scores following the implementation of professional development on data-driven instruction (chi 2 (1) = .183, p = .67). Results from surveys and interviews revealed that teachers used data to inform their instruction, indicating time as the major hindrance to their use. Implications for social change include the development of lesson plans that will empower science teachers to deliver data-based instruction and students to achieve identified academic goals.

Herrington, Tia W.

253

Hydraulic impact end effector final test report. Automation and robotics section, ER/WM-AT Program  

SciTech Connect

One tool being developed for dislodging and fragmenting the hard salt cake waste in the single-shell nuclear waste tanks at the Hanford Reservation near Richland, Washington, is the hydraulic impact end effector (HIEE). This total operates by discharging 11-in. slugs of water at ultrahigh pressures. The HIEE was designed, built, and initially tested in 1992. Work in 1993 included advanced developments of the HIEE to further investigate its fragmentation abilities and to determine more effective operating procedures. These tests showed that more fragmentation can be achieved by increasing the charge pressure of 40 kpsi to 55 kpsi and by the use of different operating procedures. The size of the material and the impact energy of the water slug fired from the HIEE are believed to be major factors in material fragmentation. The material`s ability to fracture also appears to depend on the distance a fracture or crack line must travel to a free surface. Thus, larger material is more difficult to fracture than smaller material. Discharge pressures of 40 kpsi resulted in little penetration or fracturing of the material. At 55 kpsi, however, the size and depth of the fractures increased. Nozzle geometry had a significant effect on fragment size and quantity. Fragmentation was about an order of magnitude greater when the HIEE was discharged into drilled holes rather than onto the material surface. Since surface shots tend to create craters, a multi-shot procedure, coupled with an advanced nozzle design, was used to drill (crater) deep holes into large material. With this procedure, a 600-lb block was reduced to smaller pieces without the use of any additional equipment. Through this advanced development program, the HIEE has demonstrated that it can quickly fragment salt cake material into small, easily removable fragments. The HIEE`s material fragmentation ability can be substantially increased through the use of different nozzle geometries and operating procedures.

Couture, S.

1994-02-18

254

Methods for data reduction and loads analysis of Space Shuttle Solid Rocket Booster model water impact tests  

NASA Technical Reports Server (NTRS)

The methodology used to predict full scale space shuttle solid rocket booster (SRB) water impact loads from scale model test data is described. Tests conducted included 12.5 inch and 120 inch diameter models of the SRB. Geometry and mass characteristics of the models were varied in each test series to reflect the current SRB baseline configuration. Nose first and tail first water entry modes were investigated with full-scale initial impact vertical velocities of 40 to 120 ft/sec, horizontal velocities of 0 to 60 ft/sec., and off-vertical angles of 0 to plus or minus 30 degrees. The test program included a series of tests with scaled atmospheric pressure.

1976-01-01

255

Development of a shock wave adhesion test for composite bonds by pulsed laser and mechanical impacts  

NASA Astrophysics Data System (ADS)

Evaluating the bonding quality of composite material is becoming one of the main challenges faced by aeronautic industries. This work aims to the development of a technique using shock wave, which would enable to quantify the bonding mechanical quality. Laser shock experiments were carried out. This technique enables high tensile stress generation in the thickness of composite bonds. The resulting damage has been quantified using different methods such as confocal microscopy, ultrasound and cross section observation. The discrimination between a correct bond and a weak bond was possible thanks to these experiments. Nevertheless, laser sources are not well adapted for optimization of such a test because of often fixed settings. That is why mechanical impacts on bonded composites were also performed in this work. By changing the thickness of aluminum projectiles, the generated tensile stresses by the shock wave propagation were moved toward the composite/bond interface. The made observations prove that the technique optimization is possible. The key parameters for the development of a bonding test using shock waves have been identified.

Ecault, R.; Boustie, M.; Touchard, F.; Arrigoni, M.; Berthe, L.

2014-05-01

256

Impacts Analyses Supporting the National Environmental Policy Act Environmental Assessment for the Resumption of Transient Testing Program  

SciTech Connect

This document contains the analysis details and summary of analyses conducted to evaluate the environmental impacts for the Resumption of Transient Fuel and Materials Testing Program. It provides an assessment of the impacts for the two action alternatives being evaluated in the environmental assessment. These alternatives are (1) resumption of transient testing using the Transient Reactor Test Facility (TREAT) at Idaho National Laboratory (INL) and (2) conducting transient testing using the Annular Core Research Reactor (ACRR) at Sandia National Laboratory in New Mexico (SNL/NM). Analyses are provided for radiologic emissions, other air emissions, soil contamination, and groundwater contamination that could occur (1) during normal operations, (2) as a result of accidents in one of the facilities, and (3) during transport. It does not include an assessment of the biotic, cultural resources, waste generation, or other impacts that could result from the resumption of transient testing. Analyses were conducted by technical professionals at INL and SNL/NM as noted throughout this report. The analyses are based on bounding radionuclide inventories, with the same inventories used for test materials by both alternatives and different inventories for the TREAT Reactor and ACRR. An upper value on the number of tests was assumed, with a test frequency determined by the realistic turn-around times required between experiments. The estimates provided for impacts during normal operations are based on historical emission rates and projected usage rates; therefore, they are bounding. Estimated doses for members of the public, collocated workers, and facility workers that could be incurred as a result of an accident are very conservative. They do not credit safety systems or administrative procedures (such as evacuation plans or use of personal protective equipment) that could be used to limit worker doses. Doses estimated for transportation are conservative and are based on transport of the bounding radiologic inventory that will be contained in any given test. The transportation analysis assumes all transports will contain the bounding inventory.

Annette L. Schafer; LLoyd C. Brown; David C. Carathers; Boyd D. Christensen; James J. Dahl; Mark L. Miller; Cathy Ottinger Farnum; Steven Peterson; A. Jeffrey Sondrup; Peter V. Subaiya; Daniel M. Wachs; Ruth F. Weiner

2014-02-01

257

Ethics Standards Impacting Test Development and Use: A Review of 31 Ethics Codes Impacting Practices in 35 Countries  

ERIC Educational Resources Information Center

Ethics codes are designed to protect the public by prescribing behaviors professionals are expected to exhibit. Although test use is universal, albeit reflecting strong Western influences, previous studies that examine the degree issues pertaining to test development and use and that are addressed in ethics codes of national psychological…

Leach, Mark M.; Oakland, Thomas

2007-01-01

258

Human papillomavirus testing 2007-2012: Co-testing and triage utilization and impact on subsequent clinical management.  

PubMed

In the United States, high-risk human papillomavirus (HPV) testing is recommended for women with atypical squamous cells of unknown significance (ASC-US) cytology, and co-testing with cytology and HPV is a recommended option for screening women aged ?30 years. No population-based data are available to examine utilization of HPV testing in the United States. Using the New Mexico HPV Pap Registry data resource, we describe population trends (2007-2012) in utilization and positivity rates for HPV testing as a routine co-testing screening procedure and for triage of ASC-US and other cytologic outcomes. For women aged 30-65 years co-testing increased from 5.2% in 2007 to 19.1% in 2012 (p?testing also had an HPV test. HPV positivity was age and cytology result dependent but did not show time trends. For women with negative cytology, 64% received an additional screening test within 3 years if no co-test was done or if it was positive, but this was reduced to 47% with a negative co-test. Reflex HPV testing for ASC-US cytology is well established and occurs in most women. Evidence for reflex testing is also observed following other abnormal cytology outcomes. Co-testing in women aged 30-65 years has more than tripled from 2007 to 2012, but was still only used in 19.1% of women aged 30-65 years attending for screening in 2012. Women receiving co-testing had longer repeat screening intervals, but rescreening within 3 years is still very common even with co-testing. PMID:25447979

Cuzick, Jack; Myers, Orrin; Hunt, William C; Saslow, Debbie; Castle, Philip E; Kinney, Walter; Waxman, Alan; Robertson, Michael; Wheeler, Cosette M

2014-11-19

259

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

260

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

NASA Technical Reports Server (NTRS)

The project had two objectives: 1) The primary objective was to characterize damage tolerance of composite materials. To accomplish this, polymer matrix composites were to be subjected to static indentation as well as low-velocity impacts and the results analyzed. 2) A second objective was to investigate the effects of laser shock peening on the damage tolerance of aerospace materials, such as aluminum alloys, in terms of crack nucleation and crack propagation. The impact testing was proposed to be performed using a Dynatup drop tower. The specimens were to be placed over a square opening in a steel platen and impacted with a hemispherical tup. The damage was to be characterized in the laminate specimens. The damage tolerance of aerospace alloys was to be studied by conducting fatigue tests on aluminum alloy specimens with prior shock peening treatment. The crack length was to be monitored by a microscope and the crack propagation rate, da/dN, determined.

Prabhakaran, R.

2001-01-01

261

General-purpose heat source: Research and development program. Radioisotope thermoelectric generator impact tests: RTG-1 and RTG-2  

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. 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.; Hinckley, J.E.; George, T.G.

1996-07-01

262

Research Paper 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 mete- orites. To test the first step of lithopanspermia, i.e., the impact ejection from a planet, sys- tematic shock recovery experiments within a pressure range observed in martian meteorites (5-50 GPa) were performed with dry layers of microorganisms (spores of Bacillus subtilis, cells of the endolithic cyanobacterium Chroococcidiopsis, 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

263

VALIDITY OF EFFLUENT AND AMBIENT TOXICITY TESTING FOR PREDICTING BIOLOGICAL IMPACT ON FIVE MILE CREEK, BIRMINGHAM, ALABAMA  

EPA Science Inventory

The report describes an investigation to determine the validity of laboratory toxicity tests to predict biological impact in receiving water. The first site visit in February 1983 was adversely affected by heavy rainfall immediately preceding and during the visit. Two of the trea...

264

Experimental test of the impacts of feral hogs on forest dynamics and processes in the southeastern US  

E-print Network

Experimental test of the impacts of feral hogs on forest dynamics and processes in the southeastern). For animals that feed on both seeds and vegetative structures of plants, such as feral hogs or white tailed scrofa A B S T R A C T The foraging activities of nonindigenous feral hogs (Sus scrofa) create widespread

Siemann, Evan

265

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

266

The Impact of Patient Aggression on Carers Scale: instrument derivation and psychometric testing.  

PubMed

Patient aggression towards carers constitutes a problem for patients and carers alike. Patients' aggressive behaviour often leads to adverse consequences for carers, especially nurses. Various extensive instruments have been developed to measure such adverse effects on carers. The 'Impact of Patient Aggression on Carers Scale' (IMPACS) is a short instrument intended for use in monitoring negative consequences of such incidents. The items of the IMPACS were derived basically from a review of the literature on negative effects of patient aggression on nurses. The IMPACS was administered to a convenience sample of nurses working on 14 psychiatric acute admission wards in the German speaking part of Switzerland. Factor analysis led to the exclusion of three of the original items and to an interpretable three-factor solution with all factors demonstrating eigen values higher than 1. The factors demonstrate moderate to good internal consistency. Canonical correlation analysis using the dimensions of the Maslach Burnout Inventory (MBI) produced a correlation coefficient of 0.457, thus demonstrating external reliability. In spite of some caveats such as possible response bias and the necessity of the investigation of the test-retest stability of the scale this study suggests that the IMPACS is a good measure of adverse effects and thus merits further development. PMID:16101859

Needham, Ian; Abderhalden, Chris; Halfens, Rudolph J G; Dassen, Theo; Haug, Hans-Joachim; Fischer, Joachim E

2005-09-01

267

Study of austenitic stainless steel welded with low alloy steel filler metal. [tensile and impact strength tests  

NASA Technical Reports Server (NTRS)

The tensile and impact strength properties of 316L stainless steel plate welded with low alloy steel filler metal were determined. Tests were conducted at room temperature and -100 F on standard test specimens machined from as-welded panels of various chemical compositions. No significant differences were found as the result of variations in percentage chemical composition on the impact and tensile test results. The weldments containing lower chromium and nickel as the result of dilution of parent metal from the use of the low alloy steel filler metal corroded more severely in a marine environment. The use of a protective finish, i.e., a nitrile-based paint containing aluminum powder, prevented the corrosive attack.

Burns, F. A.; Dyke, R. A., Jr.

1979-01-01

268

FIELD TESTS OF A PARTICULATE IMPACTION CURTAIN ON EMISSIONS FROM A HIGH-RISE LAYER BARN  

Microsoft Academic Search

Particulate matter (PM) emission rates from two high-rise layer barns (barns 1 and 2) were measured from 1?August 2004 to 31 January 2005. A commercial particulate impaction curtain (PIC) was installed parallel to the first floor sidewalls and upstream of the exhaust fans of barn 2 for PM reduction by impaction. Tapered element oscillating microbalance (TEOM) monitors were used to

T. T. Lim; H. Sun; J.-Q. Ni; L. Zhao; C. A. Diehl; A. J. Heber; S. M. Hanni

269

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

270

Understanding how pre-impact posture can affect injury outcome in side impact sled tests using a new tool for visualization of cadaver kinematics.  

PubMed

The effect of posture and subject-specific factors on injury outcome is an active field of research in injury biomechanics, in particular in automotive safety research where post-mortem human subjects (PMHS) are used as surrogates. Current PMHS tests routinely include acquisition of the subjects? geometry and kinematics. However, combining these two datasets to better understand the injury mechanism is still a challenge. This study investigated the connection between pre-impact posture and resulting injuries in six previously published side impact sled tests (three with a rigid wall and three with an airbag) by creating three-dimensional kinematic animations (3DKA) of the tests. The 3DKA allow qualitative assessment of parameters related to posture and their possible effect on injury outcome. The orientation of the struck scapula and the lateral leaning of the torso were identified as potentially significant parameters. The ranges of variation in these parameters were quantified and compared to the number of rib fractures for each subject: the data suggested a correlation, but there was insufficient data for a probabilistic analysis. The 3DKA were published with this study and are freely available. PMID:25579992

Donlon, John Paul; Poulard, David; Lessley, David; Riley, Patrick; Subit, Damien

2015-02-01

271

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

272

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

2012-04-01

273

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

274

Test-Analysis Correlation for Space Shuttle External Tank Foam Impacting RCC Wing Leading Edge Component Panels  

NASA Technical Reports Server (NTRS)

The Space Shuttle Columbia Accident Investigation Board recommended that NASA develop, validate, and maintain a modeling tool capable of predicting the damage threshold for debris impacts on the Space Shuttle Reinforced Carbon-Carbon (RCC) wing leading edge and nosecap assembly. The results presented in this paper are one part of a multi-level approach that supported the development of the predictive tool used to recertify the shuttle for flight following the Columbia Accident. The assessment of predictive capability was largely based on test analysis comparisons for simpler component structures. This paper provides comparisons of finite element simulations with test data for external tank foam debris impacts onto 6-in. square RCC flat panels. Both quantitative displacement and qualitative damage assessment correlations are provided. The comparisons show good agreement and provided the Space Shuttle Program with confidence in the predictive tool.

Lyle, Karen H.

2008-01-01

275

Museum Exhibition on Testing and Measurement: Scientific Principles, Social Impact of Testing, and Dialogue with the Public  

ERIC Educational Resources Information Center

This article deals with a pioneering project currently being developed, namely, the Exhibition on Testing and Measurement. This interactive traveling exhibition will be presented in science museums in Israel, the United States, and other countries. It has been conceived as an innovative means of familiarizing the public with educational…

Allalouf, Avi; Alderoqui-Pinus, Diana

2012-01-01

276

Author's personal copy Paleomagnetism of impact spherules from Lonar crater, India and a test for  

E-print Network

but nearly ubiquitous melt that has been continuously created by hypervelocity impacts over nearly all strewn fields, and spherule layers in ancient sediments (Dressler and Reimold, 2001; Koeberl, 1986; Lowe

Weiss, Benjamin P.

277

Test and Analysis Correlation of High Speed Impacts of Ice Cylinders  

NASA Technical Reports Server (NTRS)

During the space shuttle return-to-flight preparations following the Columbia accident, finite element models were needed that could predict the threshold of critical damage to the orbiter s wing leading edge from ice debris impacts. Hence, an experimental program was initiated to provide crushing data from impacted ice for use in dynamic finite element material models. A high-speed drop tower was configured to capture force time-histories of ice cylinders for impacts up to approximately 100 ft/s. At low velocity, the force-time history depended heavily on the internal crystalline structure of the ice. However, for velocities of 100 ft/s and above, the ice fractured on impact, behaved more like a fluid, and the subsequent force-time history curves were much less dependent on the internal crystalline structure.

Fasanella, Edwin L.; Boitnott, Richard L.; Kellas, Sotiris

2006-01-01

278

A Microcontroller-Based Instrument for Measuring P-Wave Speed in Impact-Echo Testing of Concrete  

Microsoft Academic Search

The objective of this paper is to describe a microcontroller-based instrument for measuring P-wave speed in impact-echo test of concrete. This measurement is based on measuring the travel time of the P-wave (Deltat) between two transducers at known distance apart. The present study developed an instrument to record the Deltat using interrupt-on-change feature of microcontroller and calculate the P-wave speed.

Slamet Riyadi; K. A. M. Nayan; M. M. Mustafa

2006-01-01

279

Testing  

MedlinePLUS

... curesma.org > learn about sma > causes & diagnoses > testing Testing An SMA diagnosis must be confirmed through genetic ... and must be identified through further testing. Prenatal Testing Prenatal testing is used to determine if a ...

280

Does KRAS Testing in Metastatic Colorectal Cancer Impact Overall Survival? A Comparative Effectiveness Study in a Population-Based Sample  

PubMed Central

Purpose Epidermal growth factor receptor (EGFR) inhibitors are approved for treating metastatic colorectal cancer (CRC); KRAS mutation testing is recommended prior to treatment. We conducted a non-inferiority analysis to examine whether KRAS testing has impacted survival in CRC patients. Patients and Methods We included 1186 metastatic CRC cases from seven health plans. A cutpoint of July, 2008, was used to define two KRAS testing time period groups: “pre-testing” (n?=?760 cases) and “post-testing” (n?=?426 cases). Overall survival (OS) was estimated, and the difference in median OS between the groups was calculated. The lower bound of the one-sided 95% confidence interval (CI) for the difference in survival was used to test the null hypothesis of post-testing inferiority. Multivariable Cox regression models were constructed to adjust for covariates. Results The median unadjusted OS was 15.4 months (95% CI: 14.0–17.5) and 12.8 months (95% CI: 10.0–15.2) in the pre- and post-testing groups, respectively. The OS difference was ?2.6 months with one-sided 95% lower confidence bound of ?5.13 months, which was less than the non-inferiority margin (?5.0 months, unadjusted p?=?0.06), leading to a failure to reject inferiority of OS in the post-testing period. In contrast, in the adjusted analysis, OS non-inferiority was identified in the post-testing period (p?=?0.001). Sensitivity analyses using cutpoints before and after July, 2008, also met the criteria for non-inferiority. Conclusion Implementation of KRAS testing did not influence CRC OS. Our data support the use of KRAS testing to guide administration of EGFR inhibitors for treatment of metastatic CRC without diminished OS. PMID:24788807

Feigelson, Heather Spencer; Zeng, Chan; Pawloski, Pamala A.; Onitilo, Adedayo A.; Richards, C. Sue; Johnson, Monique A.; Kauffman, Tia L.; Webster, Jennifer; Nyirenda, Carsie; Alexander, Gwen L.; Hwang, Clara; Cross, Deanna; McCarty, Catherine A.; Davis, Robert L.; Schwarzkopf, Denise; Williams, Andrew E.; Honda, Stacey; Daida, Yihe; Kushi, Lawrence H.; Delate, Thomas; Goddard, Katrina A. B.

2014-01-01

281

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

282

The impact of premarital HIV testing: a perspective from selected countries from the Arabian Peninsula  

Microsoft Academic Search

Although voluntary HIV testing is still more dominant than the mandatory form, in accordance with the Joint United Nations Programme on HIV\\/AIDS (UNAIDS) and Centers for Disease Control recommendations, there are still millions of people who are mandatorily tested before marriage. This article presents policies toward mandatory premarital HIV testing (PHT) in selected Arabian Peninsula countries, focusing on details of

Maria Ganczak

2010-01-01

283

The Impact of Receiving the Same Items on Consecutive Computer Adaptive Test Administrations.  

ERIC Educational Resources Information Center

Studied item exposure in a computerized adaptive test when the item selection algorithm presents examinees with questions they were asked in a previous test administration. Results with 178 repeat examinees on a medical technologists' test indicate that the combined use of an adaptive algorithm to select items and latent trait theory to estimate…

O'Neill, Thomas; Lunz, Mary E.; Thiede, Keith

2000-01-01

284

Impact of contrast sensitivity performance on visually presented neurobehavioral tests in mercury-exposed children  

Microsoft Academic Search

Presentation of neuropsychological tests on a computer screen may involve a visual challenge to the examinee. The possible need for adjustment for visual contrast sensitivity on test performance was therefore determined from data on 917 mercury-exposed children who were examined at age 7 years. Contrast sensitivity was found to be associated with performance on the computer-assisted Continuous Performance Test. However,

Philippe Grandjean; Roberta F White; Kimberly Sullivan; Frodi Debes; Katsuyuki Murata; David A Otto; Pal Weihe

2001-01-01

285

An Exploratory Study to Test the Impact on Three “Bolt-On” Items to the EQ-5D  

PubMed Central

Background Generic preference-based measures were criticized for being inappropriate in some conditions. One solution is to include “bolt-on” dimensions describing additional specific health problems. Objectives This study aimed to develop bolt-on dimensions to the EuroQol five-dimensional questionnaire (EQ-5D) and assess their impact on health state values. Methods Bolt-on dimensions were developed for vision problems, hearing problems, and tiredness. Each bolt-on dimension had three severity levels to match the EQ-5D. Three “core” EQ-5D states across a range of severity were selected, and each level of a bolt-on item was added, resulting in nine states in each condition. Health states with and without the bolt-on dimensions were valued by 300 members of the UK general public using time trade-off in face-to-face interviews, and mean health state values were compared using t tests. Regression analysis examined the impact of the bolt-on variants and the level of the bolt-on items after controlling for sociodemographic characteristics. Results Bolt-on dimensions had an impact on health state values of the EQ-5D; however, the size, direction, and significance of the impact depend on the severity of the core EQ-5D state and of the bolt-on dimension. Regression analysis demonstrated that after controlling for possible differences in sociodemographic characteristics between the groups, there were no significant differences in health state values between the three bolt-on dimensions but confirmed that the impact depended on the severity of the EQ-5D health state and the levels of bolt-on dimensions. Conclusions The impact of a bolt-on dimension on the EQ-5D depends on the core health state and the level of the bolt-on dimension. Further research in this area is encouraged. PMID:25595234

Yang, Yaling; Rowen, Donna; Brazier, John; Tsuchiya, Aki; Young, Tracey; Longworth, Louise

2015-01-01

286

Elevated Temperature Ballistic Impact Testing of PBO and Kevlar Fabrics for Application in Supersonic Jet Engine Fan Containment Systems  

NASA Technical Reports Server (NTRS)

Ballistic impact tests were conducted on fabric made from both Poly(phenylene benzobizoxazole) (PBO) and Kevlar 29 which were selected to be similar in weave pattern, areal density, and fiber denier. The projectiles were 2.54-cm- (1-in.-) long aluminum cylinders with a diameter of 1.27 cm (0.5 in.). The fabric specimens were clamped on four sides in a 30.5-cm- (12-in.-) square frame. Tests on PBO were conducted at room temperature and at 260 C (500 F). A number of PBO specimens were aged in air at 204 and 260 C (400 and 500 F) before impact testing. Kevlar specimens were tested only at room temperature and with no aging. The PBO absorbed significantly more energy than the Kevlar at both room and elevated temperatures. However, after aging at temperatures of 204 C (400 F) and above, the PBO fabric lost almost all of its energy absorbing ability. It was concluded that PBO fabric is not a feasible candidate for fan containment system applications in supersonic jet engines where operating temperatures exceed this level.

Pereira, J. Michael; Roberts Gary D.; Revilock, Duane M., Jr.

1997-01-01

287

The RETHINK project--minipigs as models for the toxicity testing of new medicines and chemicals: an impact assessment.  

PubMed

The objective of the RETHINK project was to evaluate the potential impact of toxicity testing in the minipig as an alternative approach in regulatory toxicity testing that can contribute to the replacement, refinement and reduction of animal testing (3Rs). Minipigs are strains of domestic pigs that are markedly smaller than farmyard varieties, and thus better adapted to laboratory housing. The pig closely resembles man in many features of its anatomy, physiology, biochemistry and lifestyle. In particular, the cardio-vascular system, skin and digestive tract are considered to be very good models for man. Because of these similarities the toxic effects of chemicals and drugs in pigs may resemble the effects in man more closely than do some other commonly used laboratory animals. The pig also has some features that make it a very practical model for laboratory studies. Finally, being a food animal, testing in the minipig may be more acceptable to the public than animals such as dogs or monkeys. Expert study groups (Working Groups) were assembled to review five different areas relating to the use of minipigs in regulatory safety testing: ethical issues, welfare and animal care, development of new medicines and chemicals, safety testing issues and emerging technologies in safety testing. Their conclusions are presented in the articles of this special issue. The RETHINK project was funded as a Specific Support Action under the European Community 6th Framework Programme. PMID:20685395

Forster, Roy; Bode, Gerd; Ellegaard, Lars; van der Laan, Jan Willem

2010-01-01

288

Testing three health impact assessment tools in planning: A process evaluation  

SciTech Connect

There is increasing interest in Health Impact Assessment in planning. This paper describes the results of different approaches to health impact assessment (HIA) conducted in 10 municipalities and one county in Minnesota. The paper outlines the HIA processes, outputs, and short-term outcomes concluding that it is important to engage a diverse group of stakeholders. Overall, HIA is potentially an important new tool in the planning toolkit. Strategic use of HIA to evaluate draft plans and inform plan updates and project redesigns can help raise awareness about health issues and focus planning on important human problems.

Schively Slotterback, Carissa, E-mail: cschively@umn.ed [University of Minnesota, Humphrey Institute of Public Affairs, 130 HHH Center, 301 19th Ave. S., Minneapolis, MN 55455 (United States); Forsyth, Ann, E-mail: Forsyth@cornell.ed [Cornell University (United States); Krizek, Kevin J., E-mail: krizek@colorado.ed [University of Colorado (United States); Johnson, Amanda, E-mail: gama@design.upenn.ed [University of Pennsylvania (United States); Pennucci, Aly, E-mail: aly.pennucci@ci.minneapolis.mn.u [City of Minneapolis (United States)

2011-03-15

289

Impact of Gene Patents and Licensing Practices on Access to Genetic Testing for Hearing Loss  

PubMed Central

Genetic testing for heritable hearing loss involves a mix of patented and unpatented genes, mutations and testing methods. More than half of all hearing loss is linked to inherited mutations, and five genes are most commonly tested in the United States. There are no patents on three of these genes, but Athena Diagnostics holds exclusive licenses to test for a common mutation in the GJB2 gene associated with about 50% of all cases, as well as mutations in the MTRNR1 gene. This fragmented intellectual property landscape made hearing loss a useful case study for assessing whether patent rights in genetic testing can proliferate or overlap, and whether it is possible to gather the rights necessary to perform testing. Testing for hearing loss is widely available, primarily from academic medical centers. Based on literature reviews and interviews with researchers, research on the genetics of hearing loss has generally not been impeded by patents. There is no consistent evidence of a premium in testing prices attributable to patent status. Athena Diagnostics has, however, used its intellectual property to discourage other providers from offering some tests. There is no definitive answer about the suitability of current patenting and licensing of commonly tested genes because of continuing legal uncertainty about the extent of enforcement of patent rights. Clinicians have also expressed concerns that multiplex tests will be difficult to develop because of overlapping intellectual property and conflict with Athena’s sole provider business model. PMID:20393307

Chandrasekharan, Subhashini; Fiffer, Melissa

2011-01-01

290

Testing Younger Dryas ET Impact (YDB) Evidence at Hall’s Cave, Texas  

NASA Astrophysics Data System (ADS)

Hall’s Cave, Kerrville County Texas, 167 km WSW of Austin, provides a unique opportunity for testing the presence of a chronostratigraphic datum (YDB layer) containing rare and exotic proxies, including nanodiamonds, aciniform soot, and magnetic spherules, the origins of which remain controversial, but possibly derive from a cosmic impact ~12,900 CAL BP. The karst-collapse cave in Cretaceous limestone on the Edwards Plateau contains ? 3.7 m of stratified clays grading to clayey silts recording continuous deposition from 16 ka RC yr to present. The cave’s small catchment area and mode of deposition were constant, and the stratigraphy is well dated based on 162 AMS 14C dates from individual vertebrate fossils, snails, charcoal, and sediment chemical fractions. The cave sequence contains an abundant small animal vertebrate fossil record, exhibiting biostratigraphic changes, and the timing of the late Pleistocene megafaunal extinction is consistent with that elsewhere in North America. At 151 cm below datum is the extremely sharp, smooth contact separating lower, dusky red (2.5YR3/2) clays below from overlying dark reddish brown (5YR3/3) clays (forming a 20-cm-thick dark layer) and dating to 13,000 CAL BP, at or close to the age of the YDB datum elsewhere. This appears to be the most distinctive lithologic change of the deglacial sequence. Sediments at or within 10 cm of this contact contain the local extinction of 4 species of bats, the local extinction of the prairie dog (Cynomys sp.) and perhaps other burrowing mammals in response to decrease in soil thickness, and the uppermost occurrence of 6 late Pleistocene megafaunal taxa that, although rare in the cave, do not extend younger than 12.9 ka. We collected and analyzed sediments at high resolution above and below the distinct lithologic contact at 151 cm. The red clays from 151 to 153 cm and immediately preceding the lithologic contact contain an abundance of nanodiamonds (5 different allotropes), aciniform soot at 2400 ppm, magnetic spherules, and carbon spherules, all of which we interpret as evidence for a unique chronostratigraphic marker (YDB) in the Western Hemisphere. Because the age of this horizon is ~ 13,000 CAL BP, we interpret the age of the event as the beginning of the Younger Dryas cooling. Regional soil erosion began ~15,000 CAL BP and continued until 7000 CAL BP, but dating suggests that there is no discontinuity or hiatus in deposition, and thus, the exotic materials in that layer are not considered to be erosional accumulations. Future analyses include sub-centimeter sampling over the YD boundary, quantification of nanodiamonds and other event-proxies within 1000 yr of the boundary and in sediments several 1000 years older and younger, continued refinement of the AMS 14C record to determine within 50 yr the location of 12,900 CAL BP datum and high resolution analysis of small animal biostratigraphy.

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

2009-12-01

291

A user-friendly, open-source tool to project impact and cost of diagnostic tests for tuberculosis  

PubMed Central

Most models of infectious diseases, including tuberculosis (TB), do not provide results customized to local conditions. We created a dynamic transmission model to project TB incidence, TB mortality, multidrug-resistant (MDR) TB prevalence, and incremental costs over 5 years after scale-up of nine alternative diagnostic strategies. A corresponding web-based interface allows users to specify local costs and epidemiology. In settings with little capacity for up-front investment, same-day microscopy had the greatest impact on TB incidence and became cost-saving within 5 years if delivered at $10/test. With greater initial investment, population-level scale-up of Xpert MTB/RIF or microcolony-based culture often averted 10 times more TB cases than narrowly-targeted strategies, at minimal incremental long-term cost. Xpert for smear-positive TB had reasonable impact on MDR-TB incidence, but at substantial price and little impact on overall TB incidence and mortality. This user-friendly modeling framework improves decision-makers' ability to evaluate the local impact of TB diagnostic strategies. DOI: http://dx.doi.org/10.7554/eLife.02565.001 PMID:24898755

Dowdy, David W; Andrews, Jason R; Dodd, Peter J; Gilman, Robert H

2014-01-01

292

A test of the hypothesis that impact-induced fractures are preferred sites for later tectonic activity  

NASA Technical Reports Server (NTRS)

Impact cratering has been an important process in the solar system. The cratering event is generally accompanied by faulting in adjacent terrain. Impact-induced faults are nearly ubiquitous over large areas on the terrestrial planets. The suggestion is made that these fault systems, particularly those associated with the largest impact features are preferred sites for later deformation in response to lithospheric stresses generated by other processes. The evidence is a perceived clustering of orientations of tectonic features either radial or concentric to the crater or basin in question. An opportunity exists to test this suggestion more directly on Earth. The terrestrial continents contain more than 100 known or probable impact craters, with associated geological structures mapped to varying levels of detail. Prime facie evidence for reactivation of crater-induced faults would be the occurrence of earthquakes on these faults in response to the intraplate stress field. Either an alignment of epicenters with mapped fault traces or fault plane solutions indicating slip on a plane approximately coincident with that inferred for a crater-induced fault would be sufficient to demonstrate such an association.

Solomon, Sean C.; Duxbury, Elizabeth D.

1987-01-01

293

Fatigue Strength of Diamond Coating-Substrate Interface Quantified by a Dynamic Simulation of the Inclined Impact Test  

NASA Astrophysics Data System (ADS)

Fatigue damage of the nanocrystalline diamond coating (NCD) bonding to the cemented carbide substrate develops when repetitive impact loads are applied onto the film. Thus, the highly compressive residual stresses of a NCD film are released leading to its lifting from the substrate (bulge formation). The present paper deals with the analytical description of the progressive failure of the NCD coating-substrate interface under repetitive impacts. In this context, an advanced 3D-finite element analysis model was developed for the dynamic simulation of the inclined impact test, using the LS-DYNA software. This model considers the high thermal compressive residual stresses developed in the NCD coating structure during cooling from chemical vapour deposition process temperature to ambient one. The fatigue failure of the NCD coating-substrate interface is associated with a critical shear failure stress (SFLS). The determined SFLS represents the maximum operational stress permitted in the NCD film-substrate interface in order to avoid the coating detachment initiation. According to the results obtained, the successive impacts lead to a progressive weakening of the initial film-substrate interface strength depending upon the pretreatments prior to the NCD coating deposition.

Skordaris, G.

2014-10-01

294

The reverse edge-on impact test: a small scale experiment to study non-shock ignition  

NASA Astrophysics Data System (ADS)

Low velocity impact response of HMX-based high explosives is still a challenging domain for researchers and engineers. Studies are focused on the characterization of mechanical behavior and the determination of accurate dynamic mechanical constitutive laws, the numerical simulation of highly localized fields and the determination of the hot-spot formation mechanism. This last topic mixes phenomenological assumptions at the microstructural level, about the dissipation mechanism (cristal plasticity and/or friction of micro cracks lips), to more or less empirical rules relating the macroscopic mechanical quantities to the fields of stress, strain and strain rate at the microstructural level. To contribute to this study, the punch test apllied in 1998 by the Los Alamos team to a high explosive has been revisited. A reversed edge-on impact test has been designed. It enables real-time recordings of ignition at the macroscopic level, post-mortem observations as well as numerical simulation at the mesoscale. The talk will give details about the experimental set-up, the main results obtained for various impact conditions and a first attempt to simulate the heterogeneous pressure and strain rate at the mesoscale.

Picart, Didier; Damiani, David; Doucet, Michel

2011-06-01

295

Impact on parents of receiving individualized feedback of psychological testing conducted with children as part of a research study.  

PubMed

While many researchers accept the principle that participants have a right to receive information learned from their participation in research, there are few studies examining the impact of receiving results on participants. This study was developed to examine the impact on parents of the receipt of individual results of research-based psychological testing of their children. A summary of the child's individual results of standardized measures of language and development was sent by mail with the questionnaire designed to assess the impact of receiving results. Response rate from the mailed questionnaire was 55.6% (n=74/133). Most parents reported the results as helpful and positive. The majority would receive results again. Overall, the sharing of individualized feedback from psychological testing conducted as part of a research study was well accepted by parents. This practice appears ethically permissible with appropriate support options for addressing participant concerns upon receiving the results as well options for clinical follow-up for the child. PMID:21916741

Cox, Kelly; Fernandez, Conrad V; Chambers, Christine T; Bandstra, Nancy F; Parker, Jennifer A

2011-01-01

296

A new impact test for the identification of a dynamic crack propagation criterion using a gas-gun device  

NASA Astrophysics Data System (ADS)

The modelling of damage and fracture behaviour under high rates of loadings for metallic structures presents the more and more interests for engineering design, especially for crash phenomena. In order to perform a numerical simulation of such phenomena a crack propagation criterion must be identified using adapted laboratory tests. The objective of this paper is to present a new impact test intended for the identification of a cohesive crack criterion implemented into a home-made FEM code based on Extended Finite Element Method. Therefore, a double-notched specimen is impacted using a gas-gun device in order to obtain different crack paths depending on projectile speed. A post-impact macro-photographic observation allows to measure the crack path, the angles and the advancing length. These experimental results are used as input responses in the identification procedure for determining the crack cohesive criterion parameters. Some experimental results, for an aluminium alloy crack criterion identification, are presented to illustrate the proposed approach.

Nistor, I.; Pantalé, O.; Caperaa, S.

2006-08-01

297

Testing Different Methods of Estimating the Impacts of Worker Profiling and Reemployment Services Systems.  

ERIC Educational Resources Information Center

The Worker Profiling and Reemployment Services (WPRS) program requires states to establish systems for identifying Unemployment Insurance (UI) claimants likely to exhaust their UI benefits and refers them to reemployment services. An evaluation was conducted to assess the reliability of the impact estimates provided in the evaluation of the WPRS…

Olsen, Robert B.; Decker, Paul T.

298

Dynamic properties testing of solders and modeling of electronic packages subjected to drop impact  

Microsoft Academic Search

The solder joints reliability of electronic packages during board level drop impact is a great concern for semiconductor manufacturers. Many researchers have adopted numerical simulation to investigate the drop performance of electronic package because it is fast and cost-effective. However, the solder balls, which are recognized as vital parts for the integrity of solder joints and the overall function of

Long Wen; Xingming Fu; Jianwei Zhou; Qian Wang; Jaisung Lee

2008-01-01

299

On the fracture characteristics of impact tested high density polyethylene–calcium carbonate nanocomposites  

Microsoft Academic Search

The mechanical response of calcium carbonate-reinforced high density polyethylene nanocomposite is investigated and the behavior compared with the unreinforced polyethylene processed under similar conditions. The reinforcement of high density polyethylene with nanocalcium carbonate retains adequately high strength in the temperature range of ?40 to +20°C. The positive influence of reinforcement on the impact strength is reflected in the fracture characteristics

C. Deshmane; Q. Yuan; R. D. K. Misra

2007-01-01

300

Is there any impact of cognitive remediation on an ecological test in schizophrenia?  

Microsoft Academic Search

Introduction. Cognitive deficits are commonly reported in schizophrenia and have a significant impact on the daily life of patients and on their social and work inclusion. Cognitive remediation therapies (CRT) may enhance the capabilities of schizophrenia patients. Although social and work integration is the ultimate goal of CRT, previous studies have failed to carry out a detailed assessment of the

Aurélie Royer; Anne Grosselin; Cécile Bellot; Jacques Pellet; Stéphane Billard; François Lang; Denis Brouillet; Catherine Massoubre

2011-01-01

301

Is there any impact of cognitive remediation on an ecological test in schizophrenia?  

Microsoft Academic Search

Introduction. Cognitive deficits are commonly reported in schizophrenia and have a significant impact on the daily life of patients and on their social and work inclusion. Cognitive remediation therapies (CRT) may enhance the capabilities of schizophrenia patients. Although social and work integration is the ultimate goal of CRT, previous studies have failed to carry out a detailed assessment of the

Aurélie Royer; Anne Grosselin; Cécile Bellot; Jacques Pellet; Stéphane Billard; François Lang; Denis Brouillet; Catherine Massoubre

2012-01-01

302

Impact of a standardized test package on exit examination scores and NCLEX-RN outcomes.  

PubMed

The purpose of this ex post facto correlational study was to compare exit examination scores and NCLEX-RN(®) pass rates of baccalaureate nursing students who differed in level of participation in a standardized test package. Three cohort groups emerged as a standardized test package was introduced: (a) students who did not participate in a standardized test package; (b) students with two semesters of a standardized test package; and (c) students with four semesters of a standardized test package. Benner's novice-to-expert theory framed the study in the belief that students best acquire knowledge and skills through practice and reflection. Students participating in four semesters of a standardized test package demonstrated higher exit examination scores and NCLEX-RN pass rates compared with students who did not participate in this package. This study's results could inform nurse educators about strategies to facilitate nursing student success on exit examinations and the NCLEX-RN. PMID:23413805

Homard, Catherine M

2013-03-01

303

Axial focusing of impact energy in the Earth's interior: Proof-of-principle tests of a new hypothesis  

NASA Technical Reports Server (NTRS)

A causal link between major impact events and global processes would probably require a significant change in the thermal state of the Earth's interior, presumably brought about by coupling of impact energy. One possible mechanism for such energy coupling from the surface to the deep interior would be through focusing due to axial symmetry. Antipodal focusing of surface and body waves from earthquakes is a well-known phenomenon which has previously been exploited by seismologists in studies of the Earth's deep interior. Antipodal focusing from impacts on the Moon, Mercury, and icy satellites has also been invoked by planetary scientists to explain unusual surface features opposite some of the large impact structures on these bodies. For example, 'disrupted' terrains have been observed antipodal to the Caloris impact basis on Mercury and Imbrium Basin on the Moon. Very recently there have been speculations that antipodal focusing of impact energy within the mantle may lead to flood basalt and hotspot activity, but there has not yet been an attempt at a rigorous model. A new hypothesis was proposed and preliminary proof-of-principle tests for the coupling of energy from major impacts to the mantle by axial focusing of seismic waves was performed. Because of the axial symmetry of the explosive source, the phases and amplitudes are dependent only on ray parameter (or takeoff angle) and are independent of azimuthal angle. For a symmetric and homogeneous Earth, all the seismic energy radiated by the impact at a given takeoff angle will be refocused (minus attenuation) on the axis of symmetry, regardless of the number of reflections and refractions it has experienced. Mantle material near the axis of symmetry will experience more strain cycles with much greater amplitude than elsewhere and will therefore experience more irreversible heating. The situation is very different than for a giant earthquake, which in addition to having less energy, has an asymmetric focal mechanism and a larger area. Two independent proof-of-principle approaches were used. The first makes use of seismic simulations, which are being performed with a realistic Earth model to determine the degree of focusing along the axis and to estimate the volume of material, if any, that experiences significant irreversible heating. The second involves two-dimensional hydrodynamic code simulations to determine the stress history, internal energy, and temperature rise as a function of radius along the axis.

Boslough, M. B.; Chael, E. P.; Trucano, T. G.; Kipp, M. E.; Crawford, D. A.

1994-01-01

304

Simulation of ballistic impact tests under various conditions for a nickel-base superalloy  

Microsoft Academic Search

Smooth and round notched tensile specimens with three different notch radii as well as single-edge bending specimens were tested in two high strain-rate testing machines at various strain-rates and temperatures. The experimental data were used to identify the parameters of the Johnson-Cook deformation and failure model using the evolution strategy and LS-DYNA calculations respectively. Ballistic tests with both, the projectiles

K. N. Singh; D. Klingbeil; R. Sievert

2006-01-01

305

Department of Physics' Involvement of the Impact Testing Project of the High Speed Civil Transport Program (HSCT)  

NASA Technical Reports Server (NTRS)

The project involved the impact testing of a kevlar-like woven polymer material, PBO. The purpose was to determine whether this material showed any promise as a lightweight replacement material for jet engine fan containment. The currently used metal fan containment designs carry a high drag penalty due to their weight. Projectiles were fired at samples of PBO by means of a 0.5 inch diameter Helium powered gun. The Initial plan was to encase the samples inside a purpose-built steel "hot box" for heating and ricochet containment. The research associate's responsibility was to develop the data acquisition programs and techniques necessary to determine accurately the impacting projectile's velocity. Beyond this, the Research Associate's duties include any physical computations, experimental design, and data analysis necessary.

VonMeerwall, Ernst D.

1994-01-01

306

Impact wear characteristics of engine valve and valve seat insert materials at high temperature (impact wear tests of austenitic heat-resistant steel SUH36 against Fe-base sintered alloy using plane specimens)  

Microsoft Academic Search

In order to simulate the wear of the valves and valve seat inserts of automotive engines, impact wear tests were conducted using rings made of a JIS SUH36 steel valve material and disks made of a sintered alloy valve seat insert material. Test conditions were as follows: impact energy of 0.588 J, dry air of room temperature, 200°C and 400°C,

T. Ootani; N. Yahata; A. Fujiki; A. Ehira

1995-01-01

307

Impact of Round-the-Clock, Rapid Oral Fluid HIV Testing of Women in Labor in Rural India  

PubMed Central

Background Testing pregnant women for HIV at the time of labor and delivery is the last opportunity for prevention of mother-to-child HIV transmission (PMTCT) measures, particularly in settings where women do not receive adequate antenatal care. However, HIV testing and counseling of pregnant women in labor is a challenge, especially in resource-constrained settings. In India, many rural women present for delivery without any prior antenatal care. Those who do get antenatal care are not always tested for HIV, because of deficiencies in the provision of HIV testing and counseling services. In this context, we investigated the impact of introducing round-the-clock, rapid, point-of-care HIV testing and counseling in a busy labor ward at a tertiary care hospital in rural India. Methods and Findings After they provided written informed consent, women admitted to the labor ward of a rural teaching hospital in India were offered two rapid tests on oral fluid and finger-stick specimens (OraQuick Rapid HIV-1/HIV-2 tests, OraSure Technologies). Simultaneously, venous blood was drawn for conventional HIV ELISA testing. Western blot tests were performed for confirmatory testing if women were positive by both rapid tests and dual ELISA, or where test results were discordant. Round-the-clock (24 h, 7 d/wk) abbreviated prepartum and extended postpartum counseling sessions were offered as part of the testing strategy. HIV-positive women were administered PMTCT interventions. Of 1,252 eligible women (age range 18 y to 38 y) approached for consent over a 9 mo period in 2006, 1,222 (98%) accepted HIV testing in the labor ward. Of these, 1,003 (82%) women presented with either no reports or incomplete reports of prior HIV testing results at the time of admission to the labor ward. Of 1,222 women, 15 were diagnosed as HIV-positive (on the basis of two rapid tests, dual ELISA and Western blot), yielding a seroprevalence of 1.23% (95% confidence interval [CI] 0.61%–1.8%). Of the 15 HIV test–positive women, four (27%) had presented with reported HIV status, and 11 (73%) new cases of HIV infection were detected due to rapid testing in the labor room. Thus, 11 HIV-positive women received PMTCT interventions on account of round-the-clock rapid HIV testing and counseling in the labor room. While both OraQuick tests (oral and finger-stick) were 100% specific, one false-negative result was documented (with both oral fluid and finger-stick specimens). Of the 15 HIV-infected women who delivered, 13 infants were HIV seronegative at birth and at 1 and 4 mo after delivery; two HIV-positive infants died within a month of delivery. Conclusions In a busy rural labor ward setting in India, we demonstrated that it is feasible to introduce a program of round-the-clock rapid HIV testing, including prepartum and extended postpartum counseling sessions. Our data suggest that the availability of round-the-clock rapid HIV testing resulted in successful documentation of HIV serostatus in a large proportion (82%) of rural women who were unaware of their HIV status when admitted to the labor room. In addition, 11 (73%) of a total of 15 HIV-positive women received PMTCT interventions because of round-the-clock rapid testing in the labor ward. These findings are relevant for PMTCT programs in developing countries. PMID:18462011

Pai, Nitika Pant; Barick, Ritu; Tulsky, Jacqueline P; Shivkumar, Poonam V; Cohan, Deborah; Kalantri, Shriprakash; Pai, Madhukar; Klein, Marina B; Chhabra, Shakuntala

2008-01-01

308

Impact of Gene Patents and Licensing Practices on Access to Genetic Testing for Hereditary Hemochromatosis  

PubMed Central

Hereditary hemochromatosis (HH) is an iron metabolism disorder that leads to excess iron buildup, especially in the heart, liver, and pancreas. Mutations in the HFE gene are the single most common cause of HH, which can be treated effectively if diagnosed early. Patents cover the HFE gene, related proteins, screening methods, and testing kits. Most initial testing for HH is biochemical, but HFE DNA testing or genotyping is used to confirm a diagnosis of inherited hemochromatosis. Concerns over patents covering HFE testing emerged in 2002, when scholars argued that exclusive licensing and the patent-enabled sole provider model then in place led to high prices and limited access. Critics of the sole provider model noted that the test was available at multiple laboratories prior to the enforcement of patents. By 2007, however, Bio-Rad, Limited, acquired the key intellectual property and sub-licensed it widely. In part because of broad, non-exclusive licensing, there are now multiple providers and testing technologies, and research continues. This case study illustrates how both changes in intellectual property ownership and evolving clinical utility of HFE genetic testing in the last decade have effected the licensing of patents and availability of genetic testing. PMID:20393306

Chandrasekharan, Subhashini; Pitlick, Emily; Heaney, Christopher; Cook-Deegan, Robert

2010-01-01

309

Fairness in Computerized Testing: Detecting Item Bias Using CATSIB with Impact Present  

ERIC Educational Resources Information Center

In educational assessment, there is an increasing demand for tailoring assessments to individual examinees through computer adaptive tests (CAT). As such, it is particularly important to investigate the fairness of these adaptive testing processes, which require the investigation of differential item function (DIF) to yield information about item…

Chu, Man-Wai; Lai, Hollis

2013-01-01

310

Reducing the Impact of Inappropriate Items on Reviewable Computerized Adaptive Testing  

ERIC Educational Resources Information Center

In a test, the testing score would be closer to examinee's actual ability when careless mistakes were corrected. In CAT, however, changing the answer of one item in CAT might cause the following items no longer appropriate for estimating the examinee's ability. These inappropriate items in a reviewable CAT might in turn introduce bias in ability…

Yen, Yung-Chin; Ho, Rong-Guey; Liao, Wen-Wei; Chen, Li-Ju

2012-01-01

311

Testing Report: Littleford-Day Dryer Operation: Dryer Operation Impacts of Proposed MIS Mitigation Changes  

SciTech Connect

Pacific Northwest National Laboratory performed a series of tests using the Littleford Day 22-liter dryer during investigations that evaluated changes in the melter-feed composition for the Demonstration Bulk Vitrification System. During testing, a new melter-feed formulation was developed that improved dryer performance while improving the retention of waste salts in the melter feed during vitrification.

Shimskey, Rick W.; Buchmiller, William C.; Elmore, Monte R.

2007-06-01

312

Ground based impact testing of Orbiter thermal protection system materials in support of the Columbia accident investigation  

NASA Astrophysics Data System (ADS)

On January 16, 2003, the Space Shuttle Columbia (OV-102) was launched for a nominal 16-day mission of microgravity research. Fifteen days and 20 hours after launch, and just 16 minutes before its scheduled landing, the OV-102 vehicle disintegrated during its descent. The entire crew was lost. Film and video cameras located around the launch complex captured images of the vehicle during its ascent. Of note were data that showed a piece of debris strike the port wing at approximately 82 sec after lift-off (T+82). As resulting analysis would show, the source of the debris was the left bipod ramp of the Shuttle external tank. This foam debris struck the Orbiter leading edge at sufficient velocity to breech the thermal protection system (TPS). During reentry at the end of the mission, the hot plasma impinged inside the Orbiter wing and aerodynamic forces ultimately failed the wing structure. This thesis documents the activities conducted to evaluate the effects of foam impact on Orbiter TPS. These efforts were focused on, to the greatest extent practical, replicating the impact event during the STS-107 mission ascent. This thesis fully documents the test program development, methodology, results, analysis, and conclusions to the degree that future investigators can reproduce the tests and understand the basis for decisions made during the development of the tests.

Kerr, Justin Hamilton

313

Genetic Testing for Alzheimer’s Disease and its Impact on Insurance Purchasing Behavior  

PubMed Central

New genetic tests for adult-onset diseases raise concerns about possible adverse selection in insurance markets. To test for this behavior, 148 cognitively normal individuals participating in a randomized clinical trial of genetic testing for Alzheimer’s disease (AD) were tracked for one year after risk assessment and APOE genotype disclosure. Although no significant differences were found in health, life, or disability insurance purchases, those who tested positive were 5.76 times more likely to have altered their long-term care insurance than individuals who did not receive APOE genotype disclosure. If genetic testing for AD risk assessment becomes common, it could trigger adverse selection in the long-term care insurance market. PMID:15757934

Zick, Cathleen D.; Mathews, Charles; Roberts, J. Scott; Cook-Deegan, Robert; Pokorski, Robert J.; Green, Robert C.

2006-01-01

314

Impact of Gene Patents and Licensing Practices on Access to Genetic Testing for Cystic Fibrosis  

PubMed Central

Cystic fibrosis (CF) is one of the most commonly tested autosomal recessive disorders in the US. Clinical CF is associated with mutations in the CFTR gene, of which the most common mutation among Caucasians, ?F508, was identified in 1989. The University of Michigan, Johns Hopkins University, and the Hospital for Sick Children, where much of the initial research occurred, hold key patents for CF genetic sequences, mutations and methods for detecting them. Several patents including the one that covers detection of the ?F508 mutation are jointly held by the University of Michigan and the Hospital for Sick Children in Toronto, with Michigan administering patent licensing in the US. The University of Michigan broadly licenses the ?F508 patent for genetic testing with over 60 providers of genetic testing to date. Genetic testing is now used in newborn screening, diagnosis, and reproductive decisions. Interviews with key researchers and intellectual property managers, a survey of laboratories’ prices for CF genetic testing, a review of literature on CF tests’ cost effectiveness, and a review of the developing market for CF testing provide no evidence that patents have significantly hindered access to genetic tests for CF or prevented financially cost-effective screening. Current licensing practices for cystic fibrosis (CF) genetic testing appear to facilitate both academic research and commercial testing. More than one thousand different CFTR mutations have been identified, and research continues to determine their clinical significance. Patents have been nonexclusively licensed for diagnostic use, and have been variably licensed for gene transfer and other therapeutic applications. The Cystic Fibrosis Foundation has been engaged in licensing decisions, making CF a model of collaborative and cooperative patenting and licensing practice. PMID:20393308

Chandrasekharan, Subhashini; Heaney, Christopher; James, Tamara; Conover, Chris; Cook-Deegan, Robert

2010-01-01

315

Recent development in the design, testing and impact-damage tolerance of stiffened composite panels  

NASA Technical Reports Server (NTRS)

Structural technology of laminated filamentary-composite stiffened-panel structures under combined inplane and lateral loadings is discussed. Attention is focused on: (1) methods for analyzing the behavior of these structures under load and for determining appropriate structural proportions for weight-efficient configurations; and (2) effects of impact damage and geometric imperfections on structural performance. Recent improvements in buckling analysis involving combined inplane compression and shear loadings and transverse shear deformations are presented. A computer code is described for proportioning or sizing laminate layers and cross-sectional dimensions, and the code is used to develop structural efficiency data for a variety of configurations, loading conditions, and constraint conditions. Experimental data on buckling of panels under inplane compression is presented. Mechanisms of impact damage initiation and propagation are described.

Williams, J. G.; Anderson, M. S.; Rhodes, M. D.; Starnes, J. H., Jr.; Stroud, W. J.

1979-01-01

316

Numerical Analysis on Oil Leakage of Fluid Dynamic Bearing for External Impact Test  

NASA Astrophysics Data System (ADS)

We conducted numerical simulations on the behaviors of lubricant in the fluid dynamic bearing of a mini motor shocked by external impact using a commercial software. Numerical studies on the behaviors are necessary because it is very difficult to observe the behaviors of lubricant oil and air interface in experiments although the oil leakage have to be prevented for a mini motor used for hard disk drive. To investigate the behaviors of a free surface between lubricating oil and air in the bearing, an unsteady volume-of-fluid model was utilized as well as a Navier-Stokes equation solver. Also, hybrid meshes were adapted: unstructured grids were generated in the most of large and complex geometric regions while structured grids were used in the small regions of very thin gap (a few microns) between rotor and stator. In addition, dynamic mesh and sliding mesh techniques were employed for the stable dynamic deformation of meshes corresponding to the motion of the rotor due to the impact. The results show that an oil break-up doesn't occur at the first period of an impact of 1000 ˜ 1800G along the rotor axis but it occurs in consecutive periods of 1800G. This presentation will include the effects of Weber number on the oil break-up as well as the numerical results in detail.

Baek, Sunghoon; Song, Simon

2010-11-01

317

Analysis of the 2007 Chinese ASAT Test and the Impact of its Debris on the Space Environment  

NASA Astrophysics Data System (ADS)

On 2007 January 11, the People's Republic of China conducted a successful direct-ascent ASAT test against one of their own defunct polar-orbiting weather satellites. The test produced at least 1,337 pieces of debris large enough to be routinely tracked by the US Space Surveillance Network and the NASA Orbital Debris Program Office estimated it generated over 35,000 pieces of debris down to 1 centimeter in size. While this event captured worldwide attention in the weeks and months after the test was revealed, much of the information provided in the press was inaccurate or misleading and did not appear to be based on scientific analysis of the data available to the public. In order to help the public and key policy makers more fully understand the nature of the event and its impact on the existing satellite population, the Center for Space Standards & Innovation developed a series of animations, images, and graphical analyses to more clearly portray this event and provide a factual foundation for the subsequent debate. Those materials were all made publicly available via the Internet without restriction and have appeared in numerous publications. This paper will summarize the primary areas of analysis of this event, to include a confirmation of the basic facts initially reported in Aviation Week & Space Technology, a visualization of the initial spread of the debris cloud in the first couple of hours after the attack, analysis of the impact of the debris on the LEO space environment including the number of satellites potentially affected and the increase in the number of conjunctions, a look at the current debris environment, and an assessment of the orbital lifetimes that shows that these impacts will last not for years but for centuries. The visualization techniques used to portray these analyses played a substantial role in helping the scientific community to quickly and easily convey important aspects of this event to policy makers and the public at large.

Kelso, T.

318

Testing the ureilite projectile hypothesis for the El'gygytgyn impact: Determination of siderophile element abundances and Os isotope ratios in ICDP drill core samples  

E-print Network

Testing the ureilite projectile hypothesis for the El'gygytgyn impact: Determination of siderophile element abundances and Os isotope ratios in ICDP drill core samples and melt rocks S. GODERIS1,2* , A with that of impact melt rock fragments collected near the western rim of the structure and literature data

Claeys, Philippe

319

Impact of Gene Patents and Licensing Practices on Access to Genetic Testing for Long QT Syndrome  

PubMed Central

Genetic testing for Long QT syndrome (LQTS) exemplifies patenting and exclusive licensing with different outcomes at different times. Exclusive licensing from the University of Utah changed the business model from sole provider to two US providers of LQTS testing. LQTS is associated with mutations in many genes, ten of which are now tested by two competing firms in the United States, PGxHealth and GeneDx. Until 2009, PGxHealth was sole provider, based largely on exclusive rights to patents from the University of Utah and other academic institutions. University of Utah patents were initially licensed to DNA Sciences, whose patent rights were acquired by Gennaissance, and then by Clinical Data, Inc., which owns PGxHealth. In 2002, DNA Sciences “cleared the market” by sending cease and desist patent enforcement letters to university and reference laboratories offering LQTS genetic testing. There was no test on the market for a one- to two-year period. From 2005-2008, most LQTS-related patents were controlled by Clinical Data, Inc., and its subsidiary PGxHealth. BioReference Laboratories, Inc., secured countervailing exclusive patent rights starting in 2006, also from the University of Utah, and broke the PGxHealth monopoly in early 2009, creating a duopoly for genetic testing in the United States, and expanding the number of genes for which commercial testing is available from five to ten. PMID:20393304

Angrist, Misha; Chandrasekharan, Subhashini; Heaney, Christopher; Cook-Deegan, Robert

2010-01-01

320

Factors impacting HIV testing: a review - perspectives from Australia, Canada, and the UK.  

PubMed

With the current global focus on strengthening HIV prevention through greater testing and treatment uptake, it is increasingly salient to identify and address barriers to testing. A review of the published, peer-reviewed literature and national reports from Australia, Canada, and the UK (2003-2013) on barriers to HIV testing was conducted to provide new information relevant to Australia and to complement earlier reviews from Canada and the UK. A systematic database search using keywords and a set of inclusion criteria yielded 36 studies (Australia = 13; Canada = 6; and the UK = 17). In addition 17 unpublished reports were included in the review. Our study uses a novel, comprehensive framework to describe barriers to HIV testing, and thus contributes to moving beyond the traditional patient-provider-system categorization. Within that framework, barriers are categorized as either intrapersonal (reported in 15 studies), interpersonal (21), or extrapersonal (16) and conceptualized within wider sociocultural and structural contexts. People's abilities and motivations to test (intrapersonal factors) are influenced by a host of interconnected factors spanning relationship (interpersonal) and broader socioeconomic, political and cultural (extrapersonal) factors. We suggest that the relative effects of interventions targeting barriers to HIV testing at the intrapersonal and interpersonal levels are limited by the extent to which the social determinants of health are addressed. The framework may also lend itself to thinking about the enabling factors for HIV testing, and future research may investigate the application of that framework for strategizing the most effective response. Future studies should also capture the lived experiences of barriers to HIV testing experienced by patients, especially in populations which are hard to reach based on social and geographic distance. Context-specific studies to evaluate the feasibility and effectiveness of various interventions proposed in the literature to address barriers to HIV testing are needed. PMID:25483628

Bolsewicz, K; Vallely, A; Debattista, J; Whittaker, A; Fitzgerald, L

2014-12-01

321

Cadmium Depletion Impacts on Hardening Neutron6 Spectrum for Advanced Fuel Testing in ATR  

SciTech Connect

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 with a hardened neutron spectrum. A test region is achieved with a Cadmium (Cd) filter which can harden the neutron spectrum to a spectrum similar (although still somewhat softer) to that of the liquid metal fast breeder reactor (LMFBR). A fuel test loop with a Cd-filter has been installed within the East Flux Trap (EFT) of the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL). A detailed comparison analyses between the cadmium (Cd) filter hardened neutron spectrum in the ATR and the LMFBR fast neutron spectrum have been performed using MCWO. MCWO is a set of scripting tools that are used to couple the Monte Carlo transport code MCNP with the isotope depletion and buildup code ORIGEN-2.2. The MCWO-calculated results indicate that the Cd-filter can effectively flatten the Rim-Effect and reduce the linear heat rate (LHGR) to meet the advanced fuel testing project requirements at the beginning of irradiation (BOI). However, the filtering characteristics of Cd as a strong absorber quickly depletes over time, and the Cd-filter must be replaced for every two typical operating cycles within the EFT of the ATR. The designed Cd-filter can effectively depress the LHGR in experimental fuels and harden the neutron spectrum enough to adequately flatten the Rim Effect in the test region.

Gray S. Chang

2011-05-01

322

What Factors Impact upon a Woman’s Decision to Undertake Genetic Cancer Testing?  

PubMed Central

Introduction: The advent of human genome project has lead to genetic tests that identify high-risk states for certain cancers. Many are privately marketed on the Internet. Despite the availability of tests, limited data has evaluated factors that lead to test uptake. The aim of the present study was to explore the attitudes of a cohort of new mothers toward uptake of a genetic cancer test with a 50% predictive value of cancer. Methods: A cross-sectional survey was undertaken. The project targeted women who had recently given birth at an Australian tertiary referral hospital. Women were asked about a theoretical blood test that detected an increased risk for the development of cancer. Attitudes and knowledge questionnaires were completed. Results: Of 232 consecutive women approached, 32 declined, giving a response rate of 86.2%. Only 63 (31.5%) women stated they would have the test. Absence of religious belief, higher level of education, better knowledge of terms used in genetics, an absence of concern over emotional, employment, and insurance discrimination, and previous acceptance of Down syndrome screening in pregnancy were each associated with significantly higher rate of test uptake in univariate analysis (all p?test uptake (all p?testing were the principal factors associated with decision-making. PMID:24432248

Quinlivan, Julie A.; Battikhi, Zain; Petersen, Rodney W.

2014-01-01

323

Micro-Satellite Impact Tests to Investigate Multi-Layer Insulation Fragments  

NASA Technical Reports Server (NTRS)

This paper summarizes two satellite impact experiments completed in 2008. The objective of the experiments is to investigate the physical properties of satellite fragments, including those originated from Multi-Layer Insulation (MLI) and solar panels. The ultimate goal is to use the results to improve the NASA Standard Breakup Model. The targets were two cubic micro-satellites, 20 cm by 20 cm by 20 cm in size, and approximately 1,500 g in mass. The main structure of each micro-satellite was composed of five layers; the top and bottom layers and three internal layers parallel to the top and bottom layers, plus four side panels. The top layer was equipped with solar cells that was mounted to an aluminum honeycomb sandwich panel with CFRP face sheets. The four side panels and the bottom layer are all covered with MLI. The two satellite impact experiments were conducted using the two-stage light gas gun at the Kyushu Institute of Technology in Kitakyusyu, Japan. For the first experiment (labeled Shot F), the satellite was oriented in such a way that the solar panel was facing the incoming projectile, a 39.3 g aluminum alloy solid sphere. For the second experiment (labeled Shot R), the satellite was oriented so that the solar panel was on the opposite side of the impact surface. The projectile used in the second shot was a 39.2 g aluminum alloy solid sphere. The impact speeds of Shot F and Shot R were 1.74 km/s and 1.78 km/s, respectively. The ratio of the impact kinetic energy to satellite mass for the two experiments was about 40 J/g. Both target satellites were completely fragmented, although there were noticeable differences in the characteristics of the fragments. Approximately 1,800 fragments were collected from Shot F but only 1,000 fragments were collected from Shot R. This difference primarily comes from the number of needle-like CFRP and MLI fragments. The difference in CFRP pieces depends on how the CFRP panels were fragmented. Regarding the MLI pieces, a significant difference in size and number can be observed. The largest MLI pieces in Shot F are almost of the same size as the side panels, whereas those in Shot R are larger by about a factor of two. The collected fragments and MLI pieces will be measured and analyzed using the same method as described in the NASA Standard Breakup Model. This paper will present: (1) the area-to-mass ratio, size, and mass distributions of the fragments, and (2) the differences in fragment properties between Shot F and Shot R.

Liou, J.C.; Murakami, Junko; Hanaha, Toshiya

2009-01-01

324

On the accuracy of thickness measurements in impact-echo testing of finite concrete specimens--numerical and experimental results.  

PubMed

In impact-echo testing of finite concrete structures, reflections of Rayleigh and body waves from lateral boundaries significantly affect time-domain signals and spectra. In the present paper we demonstrate by numerical simulations and experimental measurements at a concrete specimen that these reflections can lead to systematic errors in thickness determination. These effects depend not only on the dimensions of the specimen, but also on the location of the actual measuring point and on the duration of the detected time-domain signal. PMID:15047403

Schubert, Frank; Wiggenhauser, Herbert; Lausch, Regine

2004-04-01

325

Impact of point-of-care CD4 testing on linkage to HIV care: a systematic review  

PubMed Central

Introduction Point-of-care testing for CD4 cell count is considered a promising way of reducing the time to eligibility assessment for antiretroviral therapy (ART) and of increasing retention in care prior to treatment initiation. In this review, we assess the available evidence on the patient and programme impact of point-of-care CD4 testing. Methods We searched nine databases and two conference sites (up until 26 October 2013) for studies reporting patient and programme outcomes following the introduction of point-of-care CD4 testing. Where appropriate, results were pooled using random-effects methods. Results Fifteen studies, mainly from sub-Saharan Africa, were included for review, providing evidence for adults, adolescents, children and pregnant women. Compared to conventional laboratory-based testing, point-of-care CD4 testing increased the likelihood of having CD4 measured [odds ratio (OR) 4.1, 95% CI 3.5–4.9, n=2] and receiving a CD4 result (OR 2.8, 95% CI 1.5–5.6, n=6). Time to being tested was significantly reduced, by a median of nine days; time from CD4 testing to receiving the result was reduced by as much as 17 days. Evidence for increased treatment initiation was mixed. Discussion The results of this review suggest that point-of-care CD4 testing can increase retention in care prior to starting treatment and can also reduce time to eligibility assessment, which may result in more eligible patients being initiated on ART. PMID:24447595

Wynberg, Elke; Cooke, Graham; Shroufi, Amir; Reid, Steven D; Ford, Nathan

2014-01-01

326

Development of a questionnaire to test the impact of scarce materials on design in Developing Countries  

E-print Network

The objective of this thesis is to create a questionnaire that tests how designers in developing countries design with scarce resources. The questionnaire will be given to mechanical engineering students in Mexico and will ...

Grinnell, Edward (Edward M.)

2011-01-01

327

The Measured Energy Impact of Infiltration in an Outdoor Test Cell  

E-print Network

of these studies quantified energy loss reduction under a variety of outdoor weather conditions. The energy performance was investigated in an outdoor test cell with different leakage configurations and air flow rates under both infiltration and exfiltration...

Liu, M.; Claridge, D. E.

328

Impact of Instructional Sensitivity on High-Stakes Achievement Test Items: A Comparison of Methods  

E-print Network

.......................................................................................................................... 98 vii Comparison of MH Tests and LR Procedure .................................................................................. 98 How Sensitive Is Kansas Mathematics Interim Assessment... ............................................. 72 Table 9. Ranking of Sensitivity for LR and MH Methods ........................................................................ 73 Table 10. Background Information of Teachers...

Chen, Jie

2012-08-31

329

Determination of dynamic Young's modulus of concrete at early ages by impact resonance test  

Microsoft Academic Search

Young's modulus of concrete increases with hardening of the concrete at early ages. Young's modulus measured statically has\\u000a been widely used to assess the variation of modulus with curing ages. However, this method is costly because the numerous\\u000a test specimens are required. The dynamic testing technique has an advantage of performing the measurement nondestructively\\u000a without breaking specimens. Furthermore, the perceived

Kwang-Myong Lee; Dong-Soo Kim; Jee-Sang Kim

1997-01-01

330

Environmental Assessment and Finding of No Significant Impact: The Nevada Test Site Development Corporations's Desert Rock Sky Park at the Nevada Test Site  

SciTech Connect

The United States Department of Energy has prepared an Environmental Assessment (DOE/EA-1300) (EA) which analyzes the potential environmental effects of developing operating and maintaining a commercial/industrial park in Area 22 of the Nevada Test Site, between Mercury Camp and U.S. Highway 95 and east of Desert Rock Airport. The EA evaluates the potential impacts of infrastructure improvements necessary to support fill build out of the 512-acre Desert Rock Sky Park. Two alternative actions were evaluated: (1) Develop, operate and maintain a commercial/industrial park in Area 22 of the Nevada Test Site, and (2) taking no action. The purpose and need for the commercial industrial park are addressed in Section 1.0 of the EA. A detailed description of the proposed action and alternatives is in section 2.0. Section 3.0 describes the affected environment. Section 4.0 the environmental consequences of the proposed action and alternative. Cumulative effects are addressed in Section 5.0. Mitigation measures are addressed in Section 6.0. The Department of Energy determined that the proposed action of developing, operating and maintaining a commercial/industrial park in Area 22 of the Nevada Test Site would best meet the needs of the agency.

N /A

2000-03-01

331

The reverse edge-on impact test: A small scale experiment for non-shock ignition studies  

NASA Astrophysics Data System (ADS)

The microstructural hot-spot formation mechanism of non-shock HMX-based explosive ignition is still unknown. If recent optical observations made on post-mortem samples have clarified the main mechanisms of deformation at the microstructural scale, the train of each event is hardly tractable. In order to obtain realtime observation at the microscale, the punch test proposed during the 90's by the LANL team has been revisited. A reverse-edge-on impact (REOI) experiment is described in this paper. This new set-up allows (1) a constant speed of the projectile, (2) the use of various target designs, (3) macroscopic observations of the deformation and the ignition and (3) real-time optical observations at the microscale. Some results are detailed in this paper to show the interests of the REOI test configuration.

Picart, Didier; Damiani, D.; Doucet, M.

2012-03-01

332

Impact of CO2 addition to milk on selected analytical testing methods.  

PubMed

The addition of CO2 to raw milk and dairy products controls the growth of psychrotrophic bacteria at refrigeration temperatures. The objective of this study was to determine the effects of dissolved CO2 in milk on the performance of four important routine testing methods: antibiotic residue test, freezing point test, infrared milk component analysis, and alkaline phosphatase test. Raw or pasteurized whole milk was carbonated at <4 degrees C to contain approximately 0 (control), 200, 400, 600, and 1000 ppm of CO2. The addition of CO2 to raw milk up to 1000 ppm had no effect on the performance of the three antibiotic (beta-lactams) residue tests: IDEXX SNAP, Charm II Sequential Tablet, and Delvo-P Ampule. Milk freezing point decreased linearly with increasing concentration of dissolved CO2, from -0.543 degrees H (control) to -0.595 degrees H (1000 ppm). Carbonation to 1000 ppm decreased milk pH (measured at 38 degrees C) from 6.61 (control) to 6.15 (1000 ppm). The effects of CO2 on milk freezing point and pH were reversible upon removal of dissolved CO2. Increased CO2 levels in milk changed the infrared absorption spectrum of milk and caused the corrected lactose readings to decrease and the corrected fat B readings to increase. For the alkaline phosphatase tests, 0 (none), 0.05, 0.1, and 0.2% raw milk were deliberately added to pasteurized milks of six levels of carbonation (0 to 1000 ppm). The addition of CO2 did not influence the ability of Fluorophos, Charm PasLite, and Scharer Modified Rapid tests to differentiate between a pasteurized milk and a pasteurized milk with raw milk contamination. PMID:11573774

Ma, Y; Barbano, D M; Hotchkiss, J H; Murphy, S; Lynch, J M

2001-09-01

333

The Impact of Structure on Word Meaning and Fill-in-The-Blank Tests Procedures on Short-Term and Long-Term Retention of Vocabulary Items  

ERIC Educational Resources Information Center

The purpose of research described in the current study to investigate the impact of structure knowing on two types of test, i.e. word-meaning test and fill-in-the-blank test, their correlation and procedures on both short-term and long-term retention of vocabulary items. The importance of the present study, to test the condition that learners are…

Fazeli, Seyed Hossein

2009-01-01

334

Emerging Rapid Resistance Testing Methods for Clinical Microbiology Laboratories and Their Potential Impact on Patient Management  

PubMed Central

Atypical and multidrug resistance, especially ESBL and carbapenemase expressing Enterobacteriaceae, is globally spreading. Therefore, it becomes increasingly difficult to achieve therapeutic success by calculated antibiotic therapy. Consequently, rapid antibiotic resistance testing is essential. Various molecular and mass spectrometry-based approaches have been introduced in diagnostic microbiology to speed up the providing of reliable resistance data. PCR- and sequencing-based approaches are the most expensive but the most frequently applied modes of testing, suitable for the detection of resistance genes even from primary material. Next generation sequencing, based either on assessment of allelic single nucleotide polymorphisms or on the detection of nonubiquitous resistance mechanisms might allow for sequence-based bacterial resistance testing comparable to viral resistance testing on the long term. Fluorescence in situ hybridization (FISH), based on specific binding of fluorescence-labeled oligonucleotide probes, provides a less expensive molecular bridging technique. It is particularly useful for detection of resistance mechanisms based on mutations in ribosomal RNA. Approaches based on MALDI-TOF-MS, alone or in combination with molecular techniques, like PCR/electrospray ionization MS or minisequencing provide the fastest resistance results from pure colonies or even primary samples with a growing number of protocols. This review details the various approaches of rapid resistance testing, their pros and cons, and their potential use for the diagnostic laboratory. PMID:25343142

Frickmann, Hagen; Zautner, Andreas E.

2014-01-01

335

Diagnosis of food allergies: the impact of oral food challenge testing  

PubMed Central

A diagnosis of food allergies should be made based on the observation of allergic symptoms following the intake of suspected foods and the presence of allergen-specific IgE antibodies. The oral food challenge (OFC) test is the most reliable clinical procedure for diagnosing food allergies. Specific IgE testing of allergen components as well as classical crude allergen extracts helps to make a more specific diagnosis of food allergies. The Japanese Society of Pediatric Allergy and Clinical Immunology issued the 'Japanese Pediatric Guideline for Food Allergy 2012' to provide information regarding the standardized diagnosis and management of food allergies. This review summarizes recent progress in the diagnosis of food allergies, focusing on the use of specific IgE tests and the OFC procedure in accordance with the Japanese guidelines. PMID:23404053

2013-01-01

336

Impact of Epidemic Rates of Diabetes on the Chinese Blood Glucose Testing Market  

PubMed Central

China has become the country with the largest diabetes mellitus population in the world since the 1990s. About 100 million diabetes cases have been diagnosed since 2008. Handheld blood glucose meters and test strips are urgently needed for daily patient measurement. The glucose monitor with a screen-printed carbon-based glucose electrode has been in commercial production since 1994. Since then, approximately 20 companies have been involved in manufacturing and marketing meters and test strips in China. The current market and production volume and updates on technology issues are discussed in this article. PMID:22027332

Hu, Jamie; Zhang, Xian-En

2011-01-01

337

A miniaturized solid contact test with Arthrobacter globiformis for the assessment of the environmental impact of silver nanoparticles.  

PubMed

Silver nanoparticles (AgNPs) are widely applied for their antibacterial activity. Their increasing use in consumer products implies that they will find their way into the environment via wastewater-treatment plants. The aim of the present study was to compare the ecotoxicological impact of 2 differently designed AgNPs using the solid contact test for the bacterial strain Arthrobacter globiformis. In addition, a miniaturized version of this test system was established, which requires only small-sized samples because AgNPs are produced in small quantities during the design level. The results demonstrate that the solid contact test can be performed in 24-well microplates and that the miniaturized test system fulfills the validity criterion. Soils spiked with AgNPs showed a concentration-dependent reduction of Arthrobacter dehydrogenase activity for both AgNPs and Ag ions (Ag(+)). The toxic effect of the investigated AgNPs on the bacterial viability differed by 1 order of magnitude and can be related to the release of dissolved Ag(+). The release of dissolved Ag(+) can be attributed to particle size and surface area or to the fact that AgNPs are in either metallic or oxide form. Environ PMID:24477989

Engelke, Maria; Köser, Jan; Hackmann, Stephan; Zhang, Huanjun; Mädler, Lutz; Filser, Juliane

2014-05-01

338

On the Impact of Adaptive Test Question Selection for Learning Efficiency  

ERIC Educational Resources Information Center

In this paper we present a method for adaptive selection of test questions according to the individual needs of students within a web-based educational system. It functions as a combination of three particular methods. The first method is based on the course structure and focuses on the selection of the most appropriate topic for learning. The…

Barla, Michal; Bielikova, Maria; Ezzeddinne, Anna Bou; Kramar, Tomas; Simko, Marian; Vozar, Oto

2010-01-01

339

49 CFR 572.126 - Knees and knee impact test procedure.  

Code of Federal Regulations, 2014 CFR

...the knee it is within 2 degrees of horizontal and collinear with the longitudinal centerline of the femur. (4) Guide the pendulum so that there is no significant lateral vertical or rotational movement at time-zero. (5) The test probe velocity...

2014-10-01

340

Differential Impact of Brain Damage and Depression on Memory Test Performance.  

ERIC Educational Resources Information Center

Compared the effects of depression and brain damage on the Wechsler Adult Intelligence Scale Digit Span subscale and the Wechsler Memory Scale-Revised Logical Memory subtest. Performance on both tests was substantially affected by brain damage, but not by depression. Implications regarding neuropsychological assessment and rehabilitation are…

Gass, Carlton S.; Russell, Elbert W.

1986-01-01

341

Integrating GIS in the Middle School Curriculum: Impacts on Diverse Students' Standardized Test Scores  

ERIC Educational Resources Information Center

This case study conducted with 1,425 middle school students in Palm Beach County, Florida, included a treatment group receiving GIS instruction (256) and a control group without GIS instruction (1,169). Quantitative analyses on standardized test scores indicated that inclusion of GIS in middle school curriculum had a significant effect on student…

Goldstein, Donna; Alibrandi, Marsha

2013-01-01

342

Impact of oxidative stress and supplementation with vitamins E and C on testes morphology in rats.  

PubMed

The aim of the study was to verify whether an increased supply of vitamins E and C prevents the detrimental effects of ozone on the testes. The experiment was performed on 5-month-old rats exposed to ozone (0.5 ppm) for 50 days (5 h daily). Simultaneously, the animals were injected with the vitamins in 5-day intervals and at different doses (0.5, 1.5, 4.5, 5 and 15 mg of vitamin E; 0.5, 3, 9, and 50 mg of vitamin C; or both vitamins together, respectively). Gonad sections were PAS stained. In the ozonized males, depletion of germ cells occurred. In the vitamin E groups, the testes were comparable to the controls, excluding the 0.5-mg-dose vitamin E group in which perivascular fibrosis and intertubular hyalinization were observed. In the vitamin C groups, intertubular hyalinization, partial arrested spermatogenesis, and desquamation of the seminiferous epithelium appeared proportional to the vitamin dose. Additionally, premature spermiation was found at a vitamin C dose of 50-mg. In the rats injected with both vitamins, hyalinization and fibrosis appeared in addition to partial arrest of spermatogenesis and vacuolar degeneration. In conclusion, vitamin E protects against the detrimental effects of ozone in rat testes irrespective of the dose applied. This was not observed for vitamin C. Moreover, administration of higher doses of vitamin C intensified the damage to the testes caused by ozone. PMID:16394623

Jedlinska-Krakowska, Maria; Bomba, Grazyna; Jakubowski, Karol; Rotkiewicz, Tadeusz; Jana, Barbara; Penkowski, Aleksander

2006-04-01

343

Impact of Biodegradation Test Methods on the Development and Applicability of Biodegradation Qsars  

Microsoft Academic Search

The biodegradability of a substance depends on the structure and physical form of the substance, the time that has been available for acclimation, and the environmental conditions. Importantly, these later factors can be just as important as structure in determining the outcome of a biodegradation test. The development of appropriate QSARs for biodegradation and the ultimate value of the final

C. E. Cowan; T. W. Federle; R. J. Larson; T. C. J. Feijtel

1996-01-01

344

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

E-print Network

, and subsequently an effect size, is an essential step in calculating the power of an hypothesis test, but it may be difficult to specify an effect size that is meaningful for the particular situation. The effect sizes- related changes particularly difficult. Estimates of variance of infaunal abundance generated from

Burgman, Mark

345

Soil test and microbial biomass phosphorus levels impacted by potato cropping system and water management  

Technology Transfer Automated Retrieval System (TEKTRAN)

Potato crops generally require high amounts of phosphorus (P) fertilizer to reach economically acceptable yields. However, high inputs of P not only increase production cost, but also may increase the environmental risk of P runoff. We evaluated soil test P and microbial biomass P in soils from fiv...

346

Defining Group Membership: The Impact of Multiple versus Single Ethnic/Racial Categories on Testing Practices.  

ERIC Educational Resources Information Center

At the time of registration, students taking the Scholastic Assessment Tests (SAT) voluntarily complete the Student Descriptive Questionnaire (SDQ), which asks a variety of questions, one of which asks students to choose the ethnic/racial category that describes them. choosing only one category. The SAT Program undertook two studies aimed at…

Wendler, Cathy; Feigenbaum, Miriam; Escandon, Merida

347

The Impact of Various Quizzing Patterns on the Test Performance of High School Economics Students  

ERIC Educational Resources Information Center

Presenting college students, in a wide variety of content areas, with frequent announced and unannounced quizzes appears to correlate positively with enhanced test performance. The purpose of this quantitative study was to examine if similar results can be achieved with high school students in a standard economics class. Based on a theoretical…

Robertson, William L.

2010-01-01

348

Structural Damage Prediction and Analysis for Hypervelocity Impact. UDRI Light Gas Gun Test Data Summaries  

NASA Technical Reports Server (NTRS)

The HEX bumper was originally developed for use with the Defensive Shields Demonstration (DSD) Program. The University of Dayton Research Institute was a subcontractor to the Martin Marietta Astronautics Group in Denver Colorado at the time the HEX bumper was designed for use on the DSD Program. The design originated at the University and was essentially made available to interested parties. All HEX bumpers used in the DSD Program were fabricated at the University by rolling sheet stock through a special set of rollers. Two pieces of 3003-H14 aluminum sheet were rolled to produce the bumpers evaluated in Shots 4-1302 and 4-1304. A brief summary of the results of these tests is given in below. Contact prints of the multiple-exposure, orthogonal view radiographs of the debris clouds produced by the tests are attached. A sketch of the HEX bumper design is also attached.

1995-01-01

349

High-speed testing and material modeling of unfilled styrene butadiene vulcanizates at impact rates  

Microsoft Academic Search

High-speed tensile tests were performed on unfilled SBR strip and sheet specimens at room temperature. Uniaxial dynamic stress-extension ratio curves indicated three distinct regions of rate-dependent behavior when strain rates were below 180 s-1, between 180–280 s-1and above 280 s-1. With increasing strain rate, the toughness increased in the first region, remained roughly constant in the second region, and decreased

M. S. Hoo Fatt; I. Bekar

2004-01-01

350

Sales force impact on B-to-B brand equity: conceptual framework and empirical test  

Microsoft Academic Search

Purpose – This paper aims to develop and empirically test a conceptual framework explaining the influence of the sales force on brand equity relative to the product and promotion elements of the marketing mix, in the context of business-to-business marketing. Design\\/methodology\\/approach – Six research hypotheses, relating to the effects of four key drivers of B-to-B brand equity identified in a

Carsten Baumgarth; Lars Binckebanck

2011-01-01

351

The achievement impact of the inclusion model on the standardized test scores of general education students  

NASA Astrophysics Data System (ADS)

The purpose of this study was to compare the achievement of general education students within regular education classes to the achievement of general education students in inclusion/co-teach classes to determine whether there was a significant difference in the achievement between the two groups. The school district's inclusion/co-teach model included ongoing professional development support for teachers and administrators. General education teachers, special education teachers, and teacher assistants collaborated to develop instructional strategies to provide additional remediation to help students to acquire the skills needed to master course content. This quantitative study reviewed the end-of course test (EoCT) scores of Grade 10 physical science and math students within an urban school district. It is not known whether general education students in an inclusive/co-teach science or math course will demonstrate a higher achievement on the EoCT in math or science than students not in an inclusive/co-teach classroom setting. In addition, this study sought to determine if students classified as low socioeconomic status benefited from participating in co-teaching classrooms as evidenced by standardized tests. Inferential statistics were used to determine whether there was a significant difference between the achievements of the treatment group (inclusion/co-teach) and the control group (non-inclusion/co-teach). The findings can be used to provide school districts with optional instructional strategies to implement in the diverse classroom setting in the modern classroom to increase academic performance on state standardized tests.

Garrett-Rainey, Syrena

352

The Impact of Scholastic Instrumental Music and Scholastic Chess Study on the Standardized Test Scores of Students in Grades Three, Four, and Five  

ERIC Educational Resources Information Center

This study examines the impact of instrumental music study and group chess lessons on the standardized test scores of suburban elementary public school students (grades three through five) in Levittown, New York. The study divides the students into the following groups and compares the standardized test scores of each: a) instrumental music…

Martinez, Edwin E.

2012-01-01

353

Impact of assay selection and study design on the outcome of cytotoxicity testing of medical devices: The case of multi-purpose vision care solutions  

Microsoft Academic Search

Medical device biocompatibility testing usually includes a cytotoxicity component. Assay selection and protocol design often depend on a specific testing standard rather than on the characteristics of the medical device. To better understand the impact of assay selection on study outcome of unstructured medical devices, we evaluated contact lens multi-purpose solutions (MPS) in the agar diffusion, direct contact and two

David M. Lehmann; Mary E. Richardson

2010-01-01

354

Modelling the potential population impact and cost-effectiveness of self-testing for HIV: evaluation of data requirements.  

PubMed

HIV testing uptake has increased dramatically in recent years in resource limited settings. Nevertheless, over 50% of the people living with HIV are still unaware of their status. HIV self-testing (HIVST) is a potential new approach to facilitate further uptake of testing which requires consideration, taking into account economic factors. Mathematical models and associated economic analysis can provide useful assistance in decision-making processes, offering insight, in this case, into the potential long-term impact at a population level and the price-point at which free or subsidized HIVST would be cost-effective in a given setting. However, models are based on assumptions, and if the required data are sparse or limited, this uncertainty will be reflected in the results from mathematical models. The aim of this paper is to describe the issues encountered in modeling the cost-effectiveness of introducing HIVST, to indicate the evidence needed to support various modeling assumptions, and thus which data on HIVST would be most beneficial to collect. PMID:24957978

Cambiano, Valentina; Mavedzenge, Sue Napierala; Phillips, Andrew

2014-07-01

355

Impact of test sensitivity and specificity on pig producer incentives to control Mycobacterium avium infections in finishing pigs.  

PubMed

In this paper we analyze the impact of the sensitivity and specificity of a Mycobacterium avium (Ma) test on pig producer incentives to control Ma in finishing pigs. A possible Ma control system which includes a serodiagnostic test and a penalty on finishing pigs in herds detected with Ma infection was modelled. Using a dynamic optimization model and a grid search of deliveries of herds from pig producers to slaughterhouse, optimal control measures for pig producers and optimal penalty values for deliveries with increased Ma risk were identified for different sensitivity and specificity values. Results showed that higher sensitivity and lower specificity induced use of more intense control measures and resulted in higher pig producer costs and lower Ma seroprevalence. The minimal penalty value needed to comply with a threshold for Ma seroprevalence in finishing pigs at slaughter was lower at higher sensitivity and lower specificity. With imperfect specificity a larger sample size decreased pig producer incentives to control Ma seroprevalence, because the higher number of false positives resulted in an increased probability of rejecting a batch of finishing pigs irrespective of whether the pig producer applied control measures. We conclude that test sensitivity and specificity must be considered in incentive system design to induce pig producers to control Ma in finishing pigs with minimum negative effects. PMID:23777649

van Wagenberg, Coen P A; Backus, Gé B C; Wisselink, Henk J; van der Vorst, Jack G A J; Urlings, Bert A P

2013-09-01

356

The changing landscape of genetic testing and its impact on clinical and laboratory services and research in Europe  

PubMed Central

The arrival of new genetic technologies that allow efficient examination of the whole human genome (microarray, next-generation sequencing) will impact upon both laboratories (cytogenetic and molecular genetics in the first instance) and clinical/medical genetic services. The interpretation of analytical results in terms of their clinical relevance and the predicted health status poses a challenge to both laboratory and clinical geneticists, due to the wealth and complexity of the information obtained. There is a need to discuss how to best restructure the genetic services logistically and to determine the clinical utility of genetic testing so that patients can receive appropriate advice and genetic testing. To weigh up the questions and challenges of the new genetic technologies, the European Society of Human Genetics (ESHG) held a series of workshops on 10 June 2010 in Gothenburg. This was part of an ESHG satellite symposium on the ‘Changing landscape of genetic testing', co-organized by the ESHG Genetic Services Quality and Public and Professional Policy Committees. The audience consisted of a mix of geneticists, ethicists, social scientists and lawyers. In this paper, we summarize the discussions during the workshops and present some of the identified ways forward to improve and adapt the genetic services so that patients receive accurate and relevant information. This paper covers ethics, clinical utility, primary care, genetic services and the blurring boundaries between healthcare and research. PMID:22453292

Hastings, Ros; de Wert, Guido; Fowler, Brian; Krawczak, Michael; Vermeulen, Eric; Bakker, Egbert; Borry, Pascal; Dondorp, Wybo; Nijsingh, Niels; Barton, David; Schmidtke, Jörg; van El, Carla G; Vermeesch, Joris; Stol, Yrrah; Carmen Howard, Heidi; Cornel, Martina C

2012-01-01

357

Microbial rock inhabitants survive hypervelocity impacts on Mars-like host planets: first phase of lithopanspermia experimentally tested.  

PubMed

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 (5-50 GPa) were performed with dry layers of microorganisms (spores of Bacillus subtilis, cells of the endolithic cyanobacterium Chroococcidiopsis, and thalli and ascocarps of the lichen Xanthoria elegans) sandwiched between gabbro discs (martian analogue rock). Actual shock pressures were determined by refractive index measurements and Raman spectroscopy, and shock temperature profiles were calculated. Pressure-effect curves were constructed for survival of B. subtilis spores and Chroococcidiopsis cells from the number of colony-forming units, and for vitality of the photobiont and mycobiont of Xanthoria elegans from confocal laser scanning microscopy after live/dead staining (FUN-I). A vital launch window for the transport of rock-colonizing microorganisms from a Mars-like planet was inferred, which encompasses shock pressures in the range of 5 to about 40 GPa for the bacterial endospores and the lichens, and a more limited shock pressure range for the cyanobacterium (from 5-10 GPa). The results support concepts of viable impact ejections from Mars-like planets and the possibility of reseeding early Earth after asteroid cataclysms. PMID:18237257

Horneck, Gerda; Stöffler, Dieter; Ott, Sieglinde; Hornemann, Ulrich; Cockell, Charles S; Moeller, Ralf; Meyer, Cornelia; de Vera, Jean-Pierre; Fritz, Jörg; Schade, Sara; Artemieva, Natalia A

2008-02-01

358

Modified Smoothed Particle Hydrodynamics (MSPH) basis functions for meshless methods, and their application to axisymmetric Taylor impact test  

NASA Astrophysics Data System (ADS)

The Modified Smoothed Particle Hydrodynamics (MSPH) method proposed earlier by the authors and applied to the analysis of transient two-dimensional (2-D) heat conduction, 1-D transient simple shearing deformations of a thermoviscoplastic material, 1-D wave propagation in a functionally graded plate, and 2-D elastodynamic crack propagation is extended to the analysis of axisymmetric deformations of a thermoviscoplastic material. In the MSPH method, different shape functions are used to find kernel estimates of the function, and of its first and second derivatives. It differs from the classical finite element method in which derivatives of a function are usually obtained by differentiating the shape function used to approximate the function. It is shown that results computed with the MSPH method for the Noh problem agree well with its analytical solution. The MSPH basis functions can be used in any meshless method to numerically solve either static or dynamic problems. The method is then applied to analyze transient deformations of a cylindrical rod impacting at normal incidence a rigid smooth stationary flat plate. The computed solution is found to agree very well with those obtained by analyzing axisymmetric and 3-D transient deformations of the rod with the commercial code LS-DYNA. The final length of the deformed rod, the final radius of the impacted face, and the final length of the relatively undeformed portion of the rod for twelve test configurations computed with the MSPH method are also found to agree well with their corresponding experimental values.

Batra, R. C.; Zhang, G. M.

359

Design and testing of a novel piezoelectric micro-motor actuated by asymmetrical inertial impact driving principle  

NASA Astrophysics Data System (ADS)

In this paper, an asymmetrical inertial impact driving principle is first proposed, and accordingly a novel piezoelectrically actuated linear micro-motor is developed. It is driven by the inertial impact force generated by piezoelectric smart cantilever (PSC) with asymmetrical clamping locations during a driving cycle. When the PSC is excited by typical harmonic voltage signals, different equivalent stiffness will be induced due to its asymmetrical clamping locations when it is vibrating back and forth, leading to a tiny displacement difference on the two opposite directions in a cycle, and then the accumulation of tiny displacement difference will allow directional movements. A prototype of the proposed motor has been developed and investigated by means of experimental tests. The motion and dynamics characteristics of the prototype are well studied. The experimental results demonstrate that the resolution of the micro-motor is 0.02 ?m, the maximum velocity is 16.87 mm/s, and the maximum loading capacity can reach up to 1 kg with a voltage of 100 V and 35 Hz.

Zeng, Ping; Sun, Shujie; Li, Li'an; Xu, Feng; Cheng, Guangming

2014-03-01

360

Design and testing of a novel piezoelectric micro-motor actuated by asymmetrical inertial impact driving principle.  

PubMed

In this paper, an asymmetrical inertial impact driving principle is first proposed, and accordingly a novel piezoelectrically actuated linear micro-motor is developed. It is driven by the inertial impact force generated by piezoelectric smart cantilever (PSC) with asymmetrical clamping locations during a driving cycle. When the PSC is excited by typical harmonic voltage signals, different equivalent stiffness will be induced due to its asymmetrical clamping locations when it is vibrating back and forth, leading to a tiny displacement difference on the two opposite directions in a cycle, and then the accumulation of tiny displacement difference will allow directional movements. A prototype of the proposed motor has been developed and investigated by means of experimental tests. The motion and dynamics characteristics of the prototype are well studied. The experimental results demonstrate that the resolution of the micro-motor is 0.02 ?m, the maximum velocity is 16.87 mm/s, and the maximum loading capacity can reach up to 1 kg with a voltage of 100 V and 35 Hz. PMID:24689611

Zeng, Ping; Sun, Shujie; Li, Li'an; Xu, Feng; Cheng, Guangming

2014-03-01

361

High energy beam impact tests on a LHC tertiary collimator at the CERN high-radiation to materials facility  

NASA Astrophysics Data System (ADS)

The correct functioning of a collimation system is crucial to safely operate highly energetic particle accelerators, such as the Large Hadron Collider (LHC). The requirements to handle high intensity beams can be demanding. In this respect, investigating the consequences of LHC particle beams hitting tertiary collimators (TCTs) in the experimental regions is a fundamental issue for machine protection. An experimental test was designed to investigate the robustness and effects of beam accidents on a fully assembled collimator, based on accident scenarios in the LHC. This experiment, carried out at the CERN High-Radiation to Materials (HiRadMat) facility, involved 440 GeV proton beam impacts of different intensities on the jaws of a horizontal TCT. This paper presents the experimental setup and the preliminary results obtained, together with some first outcomes from visual inspection and a comparison of such results with numerical simulations.

Cauchi, Marija; Aberle, O.; Assmann, R. W.; Bertarelli, A.; Carra, F.; Cornelis, K.; Dallocchio, A.; Deboy, D.; Lari, L.; Redaelli, S.; Rossi, A.; Salvachua, B.; Mollicone, P.; Sammut, N.

2014-02-01

362

The impact of prior knowledge from participant instructions in a mock crime P300 Concealed Information Test.  

PubMed

In P300-Concealed Information Tests used with mock crime scenarios, the amount of detail revealed to a participant prior to the commission of the mock crime can have a serious impact on a study's validity. We predicted that exposure to crime details through instructions would bias detection rates toward enhanced sensitivity. In a 2×2 factorial design, participants were either informed (through mock crime instructions) or naïve as to the identity of a to-be-stolen item, and then either committed (guilty) or did not commit (innocent) the crime. Results showed that prior knowledge of the stolen item was sufficient to cause 69% of innocent-informed participants to be incorrectly classified as guilty. Further, we found a trend toward enhanced detection rate for guilty-informed participants over guilty-naïve participants. Results suggest that revealing details to participants through instructions biases detection rates in the P300-CIT toward enhanced sensitivity. PMID:25128283

Winograd, Michael R; Rosenfeld, J Peter

2014-12-01

363

IMPACT OF CORONARY ARTERY CALCIUM SCANNING ON CORONARY RISK FACTORS AND DOWNSTREAM TESTING: A PROSPECTIVE RANDOMIZED TRIAL  

PubMed Central

OBJECTIVE We conducted a prospective randomized trial to compare the clinical impact of conventional risk factor modification to that associated with coronary artery calcium (CAC) scanning. BACKGROUND Although CAC scanning predicts cardiac events, its impact on subsequent medical management and CAD risk is not known. METHODS We assigned 2,137 volunteers to groups that did versus did not undergo CAC scanning before risk factor counseling. The primary end-point was 4-year change in CAD risk factors and Framingham Risk Score (FRS). We also compared the groups for differences in downstream medical resource utilization. RESULTS Compared to the no-scan group, the scan group showed a net favorable change in systolic blood pressure (p=0.02), LDL-cholesterol (p=0.04), waist circumference for those with increased abdominal girth (p=0.01), and tendency to weight loss among overweight subjects (p=0.07). While mean FRS rose in the no-scan group, it remained static in the scan group (0.7±5.1 versus 0.002±4.9, p=0.003). Within the scan group, increasing baseline CAC score was associated with a dose-response improvement in systolic and diastolic blood pressure (p<0.001), total cholesterol (p<0.001), LDL-cholesterol (p<0.001), triglycerides (p<0.001), weight (p<0.001) and FRS (p=0.003). Downstream medical testing and costs in the scan group were comparable versus the no-scan group, balanced by lower and higher resource utilization for those with normal CAC scans and CAC scores ?400, respectively. CONCLUSIONS As compared to no scanning, randomization to CAC scanning was associated with superior CAD risk factor control without increasing downstream medical testing. Further study of CAC scanning for improvement of cardiovascular outcomes may be warranted. (ClinicalTrials.gov, number NCT00927693). PMID:21439754

Rozanski, Alan; Gransar, Heidi; Shaw, Leslee J.; Kim, Johanna; Miranda-Peats, Lisa; Wong, Nathan D.; Rana, Jamal S.; Orakzai, Raza; Hayes, Sean W.; Friedman, John D.; Thomson, Louise; Polk, Donna; Min, James; Budoff, Matt; Berman, Daniel S.

2011-01-01

364

Social physique anxiety and sociocultural attitudes toward appearance impact on orthorexia test in fitness participants.  

PubMed

This study investigates how scores on the Social Physique Anxiety Scale (SPAS) and the Sociocultural Attitudes Towards Appearance Questionnaire (SATAQ) relate to Bratman's orthorexia test (BOT) scores with regard to age, sex, and self-reported exercise frequency and duration in a sample of Swedish participants in fitness center activities. A total of 251 participants (166 women and 85 men) completed the SPAS, the SATAQ, and a questionnaire focusing on exercise frequency and duration. The results indicated that the SATAQ subdomain internalization could itself explain the variation in BOT results. In women, the results indicated that exercise frequency, followed by SPAS score and the SATAQ subdomains internalization and awareness, could together explain the variation in BOT results. Fitness centers could make a point of emphasizing that some physical ideals are neither healthy nor realistic, thus strengthening member self-image and preventing social physique anxiety, eating disorders, and negative attitudes toward appearance. PMID:18067519

Eriksson, L; Baigi, A; Marklund, B; Lindgren, E C

2008-06-01

365

How antipsychotics impact the different dimensions of Schizophrenia: a test of competing hypotheses.  

PubMed

The clinical expression of schizophrenia is generally reported to be expressed by three to five different factors (i.e. positive, negative, disorganization, excitability, anxiety-depression symptoms). It is often claimed that antipsychotic medications are particularly helpful for positive symptoms, but not for the others, suggesting a differential efficacy for different aspects of the disorder. We formally tested this claim. Using Structural Equation Modeling in two large [1884 patients] clinical trials in schizophrenia, we compared the model of a common general effect of antipsychotics to models whereby the antipsychotics have multiple and differential effects on the different factors of the illness. We validated the generalizability of the model in further trials involving antipsychotics in chronic [1460 patients] and first-episode patients [1053 patients]. Across different populations, different trials and different antipsychotics - the best-fitting model suggests that symptom response in schizophrenia is underpinned by a single general effect with secondary and minor lower-order effects on specific symptom domains. This single-factor model explained nearly 80% of the variance, was superior to the assumption of unique efficacy for specific domains; and replicated across antipsychotics and illness stages. Despite theoretical and pharmacological claims the differential efficacy of antipsychotics on the various dimensions of schizophrenia is not supported in the prevailing data. The implication of this finding for the measurement of treatment response and our understanding of the neurobiology of antipsychotic action, for clinical practice and for future drug development are discussed. PMID:24862257

Marques, Tiago Reis; Levine, Stephen Z; Reichenberg, Avi; Kahn, Rene; Derks, Eske M; Fleischhacker, Wolfgang W; Rabinowitz, Jonathan; Kapur, Shitij

2014-08-01

366

Agronomic and environmental soil test phosphorus method comparisons and diet modification impacts on poultry litter phosphorus composition  

NASA Astrophysics Data System (ADS)

Phosphorus (P) loss from agricultural fields to freshwater ecosystems is of increasing concern due to elevated soil P levels brought on by long term and excessive application rates of manure and commercial fertilizers. Both Bray P1 and Mehlich-3 P (PM3) soil tests are used in Indiana to make fertilizer recommendations and to limit manure application rates. The Mehlich-3 P Saturation Ratio (PSRM3) has been proposed as an alternative to PM3 and the ammonium oxalate degree of P saturation (DPSOX) for assessing the risk of soluble P loss from soils. We assessed the correlations among agronomic soil test methods (PM3 and Bray P1), environmental soil test methods (soluble P: deionized water, DW; artificial rainwater, ARW; dilute salt extractable P, DSEP), ammonium oxalate P (POX), total P (TP), and P saturation methods from 565 Indiana surface soil samples. Significant correlations were found among the various STP methods evaluated, and Bray P1 and PM3 displayed the strongest coefficient of correlation (r = 0.93, p < 0.0001). Mehlich-3 P had stronger correlations with TP and POX compared to correlations between Bray P1 and TP and POX, and their correlations were all highly significant ( p < 0.0001). Additionally, all soluble P forms were significantly correlated with Bray P1, PM3, and POX, and the correlations between Bray P1 and all three soluble P measures were consistently greater than those between other soil test methods and the soluble measures. Significant correlations were found between PM3 and PSRM3 (r = 0.93, p < 0.0001) and between PSRM3 and DPSOX (r = 0.92, p < 0.0001), suggesting that PSRM3 can be as effective as DPSOX to identify soils with a greater potential to contribute bioavailable (not just soluble) P to surface and ground water. We conclude that both PM3 and PSRM3 can be integrated into more comprehensive P loss risk algorithms to mitigate elevated P concentration in surface and ground water. The PSRM3 can be used as an alternative to PM3 as it does account for extractable Al and Fe, the primary P sorbents in most soils. Although Bray P1 is an appropriate soil test based on the data generated in this study, it would not be the most practical soil test as it is not considered a multi-element extraction in most states. Since PM3 was strongly correlated with Bray P1 and the benefit of using PM3as a multi-element extractant from which the PSRM3 can be calculated, it is probably the most practical test to use for both agronomic and environmental soil P assessment. We also evaluated the impacts of diets containing different amounts of DDGS and dietary fumeric acid on P excretion and P transformations during litter storage. Total P and phytate P were significantly (p< 0.0001) affected by dietary inclusion of DDGS; where DDGS inclusion of 20% decreased TP by 16, 15, and 16% for day 0, 7, and 14 of storage, respectively compared to commercial diets. Phytate P, on the other hand, was reduced by 38, 37, and 47% for day 0, 7, and 14 of storage, respectively. Overall, DDGS influenced the forms of P in poultry litter with phytate P being the most impacted. The inclusion of DDGS in poultry diets seems promising as it can potentially decrease the levels of phytate P in poultry litters, which is of may be of environmental significance as phytate P can desorb inorganic P in soils.

Eugene, Branly

367

Impact Behavior of A356 Foundry Alloys in the Presence of Trace Elements Ni and V  

NASA Astrophysics Data System (ADS)

In the present work, the impact behavior of unmodified A356 alloys with the addition of Ni or V in as-cast and T6 heat-treated conditions was assessed. Charpy V-notched specimens obtained from sand and permanent mold casting showed low total absorbed energy average values (W t < 2 J). SEM analysis of fracture profiles and surfaces indicated a Si-driven crack propagation with a predominant transgranular fracture mode. Occasionally, intergranular contributions to fracture were detected in the permanent mold cast alloys due to the locally finer microstructure. Concurrent mechanisms related to the chemical composition, solidification conditions and heat treatment were found to control the impact properties of the alloys. While the trace element Ni exerted only minor effects on the impact toughness of the A356 alloy, V had a strong influence: (i) V-containing sand cast alloys absorbed slightly higher impact energies compared to the corresponding A356 base alloys; (ii) in the permanent mold cast alloys, V in solid solution led to a considerable loss of ductility, which in turn decreased the total absorbed energy.

Casari, Daniele; Ludwig, Thomas H.; Merlin, Mattia; Arnberg, Lars; Garagnani, Gian Luca

2014-12-01

368

Hypervelocity Impact Testing of International Space Station Meteoroid/Orbital Debris Shielding Using an Inhibited Shaped Charge Launcher  

NASA Technical Reports Server (NTRS)

Engineers at the NASA Johnson Space Center have conducted hypervelocity impact (HVI) performance evaluations of spacecraft meteoroid and orbital debris (M/OD) shields at velocities in excess of 7 km/s. The inhibited shaped charge launcher (ISCL), developed by the Southwest Research Institute, launches hollow, circular, cylindrical jet tips to approximately 11 km/s. Since traditional M/OD shield ballistic limit performance is defined as the diameter of sphere required to just perforate or spall a spacecraft pressure wall, engineers must decide how to compare ISCL derived data with those of the spherical impactor data set. Knowing the mass of the ISCL impactor, an equivalent sphere diameter may be calculated. This approach is conservative since ISCL jet tips are more damaging than equal mass spheres. A total of 12 tests were recently conducted at the Southwest Research Institute (SWRI) on International Space Station M/OD shields. Results of these tests are presented and compared to existing ballistic limit equations. Modification of these equations is suggested based on the results.

Kerr, Justin H.; Grosch, Donald

2001-01-01

369

Impact of expected changes in national papanicolaou test volume on the cytotechnology labor market: an impending crisis.  

PubMed

With the new screening and treatment guidelines and the prospect of human papillomavirus vaccination for adolescents, the current total volume of Papanicolaou (Pap) tests will be significantly reduced. We used available data to assess the current supply and demand in the cytotechnology labor market and how an expected change in Pap test volume impacts this market. Cytotechnologists' data were obtained from the American Society for Clinical Pathology (ASCP) Board of Registry and the Center for Medicare and Medicaid Services. Data for wages and vacancies were obtained from American Society for Cytotechnologists and ASCP Surveys. Cytotechnology training program data were obtained from annual reports of the Cytotechnology Programs Review Committee of American Society for Cytopathology. In the current market, the demand for cytotechnologists increases by 3.6% and the supply by 4.0% each year. At any given time, there is a vacancy rate of 3%. In the coming years, the demand will decrease remarkably with a projected total demand for cytotechnologists of 5,623 instead of 8,033 by the year 2010 and of 8,538 instead of 14,146 by the year 2026. The cytotechnology market faces an impending crisis. There is a high need for prospectively collected accurate data on demand for and supply of cytotechnologists. PMID:17875520

Eltoum, Isam A; Roberson, Janie

2007-10-01

370

The impact of isometric handgrip testing on left ventricular twist mechanics  

PubMed Central

Left ventricular (LV) rotation occurs due to contraction of obliquely oriented myocardial fibres. Left ventricular twist (LVT) results from rotation of the apex and base in opposite directions. Although LVT is altered in various cardiac diseases, physiological factors that affect LVT remain incompletely understood. Isometric handgrip testing (IHGT), a well-established laboratory-based technique to increase LV afterload, was performed for 3 min at 40% maximum force generation in healthy human subjects (n = 18, mean age 29.7 ± 2.7 years). Speckle-tracking echocardiography was used to measure LV volumes, LV apical and basal rotation, peak systolic LVT and peak early diastolic untwisting rate (UTR) at rest and at peak IHGT. IHGT led to significant increase in systemic blood pressure (systolic, 120.6 ± 9.7 vs. 155.6 ± 14.5 mmHg, P < 0.001; diastolic, 67.5 ± 6.4 vs. 94.1 ± 21.1 mmHg, P < 0.001) and LV end-systolic volume (44.2 ± 7.8 vs. 50.5 ± 10.8 ml, P = 0.005), as well as a significant increase in heart rate (62.8 ± 11.7 vs. 84.7 ± 13.8 beats min?1; P < 0.001). IHGT produced a significant acute reduction in LV stroke volume (63.9 ± 12.0 vs. 49.4 ± 7.8 ml, P < 0.001). In this setting, there was a significant decrease in peak systolic apical rotation (11.9 ± 3.0 vs. 8.6 ± 2.2 deg, P < 0.001) and a resultant 25% decrease in peak systolic LVT (16.6 ± 2.8 vs. 12.5 ± 2.8 deg, P < 0.001). The magnitude of peak early diastolic UTR did not change (?114.5 ± 26.4 vs. ?110.6 ± 39.8 deg s?1, P = 0.71). Peak systolic apical rotation and LVT decrease during IHGT in healthy humans. This impairment of LV twist mechanics may in part underlie the LV dysfunction that can occur in the clinical context of acute increase in afterload. PMID:22890704

Weiner, Rory B; Weyman, Arthur E; Kim, Jonathan H; Wang, Thomas J; Picard, Michael H; Baggish, Aaron L

2012-01-01

371

The origin of Phobos grooves from ejecta launched from impact craters on Mars: Tests of the hypothesis  

NASA Astrophysics Data System (ADS)

The surface of the martian moon Phobos is characterized by parallel and intersecting grooves that bear resemblance to secondary crater chains observed on planetary surfaces. Murray (2011) has hypothesized that the main groove-forming process on Phobos is the intersection of Phobos with ejecta from primary impact events on Mars to produce chains of secondary craters. The hypothesis infers a pattern of parallel jets of ejecta, either fluidized or solidified, that break into equally-spaced fragments and disperse uniformly along-trajectory during the flight from Mars to Phobos. At the moment of impact with Phobos the dispersed fragments emplace secondary craters that are aligned along strike corresponding to the flight pattern of ejecta along trajectory. The aspects of the characteristics of grooves on Phobos cited by this hypothesis that might be explained by secondary ejecta include: their observed linearity, parallelism, planar alignment, pitted nature, change in character along strike, and a "zone of avoidance" where ejecta from Mars is predicted not to impact (Murray, 2011). To test the hypothesis we plot precise Keplerian orbits for ejecta from Mars (elliptical and hyperbolic with periapsis located below the surface of Mars). From these trajectories we: (1) set the fragment dispersion limits of ejecta patterns required to emplace the more typically well-organized parallel grooves observed in returned images from Phobos; (2) plot ranges of the ejecta flight durations from Mars to Phobos and map regions of exposure; (3) utilize the same exposure map to observe trajectory-defined ejecta exposure shadows; (4) observe hemispheric exposure in response to shorter and longer durations of ejecta flight; (5) assess the viability of ejecta emplacing the large family of grooves covering most of the northern hemisphere of Phobos; and (6) plot the arrival of parallel lines of ejecta emplacing chains of craters at oblique incident angles. We also assess the bulk volume of ejecta from martian impact events and the number of events that are necessary to supply sufficient bulk densities of secondary impactor fragments. On the basis of our analysis, we find that six major predictions of the Murray hypothesis are not consistent with a wide range of Mars ejecta emplacement models and observations as follows: (1) To emplace families of parallel grooves as observed in the most common features (grooves that manifest virtually no positional defects), and to reach the maximum geographic extent of Phobos, grid patterns of ejecta fragments must be produced with nearly identical diameters (often tens of thousands in number) and must launch with virtually zero rates of dispersion (<1 mm/s and <1.0 ?rad in all degrees of freedom) into fixed patterns of arrays where fragment dispersion is referenced to a common datum point for the duration of flights from Mars to Phobos of up to 3 h. (2) Half of the areal region observed as a "zone of avoidance" (where grooves are absent on the trailing orbital apex of Phobos) is directly exposed to ejecta trajectories from the surface of Mars, which suggests that the "zone of avoidance" is unrelated to ejecta trajectories. (3) Several families of grooves display groove segments that are observed in a region of Phobos that is shadowed from martian ejecta trajectories for flight durations up to 3 h. Where the Murray hypothesis predicts the emplacement of groove families from a single ejecta plume, this strongly suggests that these families of grooves could not have been produced by martian impact ejecta. (4) To reach increasingly westerly locations of Phobos ejecta must travel in space for substantially longer flight times (up to 20X) which would produce substantially lower secondary crater densities on the anti-Mars side of Phobos and observably reduce their pit organization. This is not observed. (5) The largest family of grooves cannot be emplaced by any valid trajectory from Mars in its present day or ancient orbit. (6) If emplaced by grid patterns of ejecta, the irregular to

Ramsley, Kenneth R.; Head, James W.

2013-01-01

372

Development and Testing of a Simple Calibration Technique for Long-Term Hydrological Impact Assessment (L-THIA) Model  

NASA Astrophysics Data System (ADS)

Hydrological studies are significant part of every engineering, developmental project and geological studies done to assess and understand the interactions between the hydrology and the environment. Such studies are generally conducted before the beginning of the project as well as after the project is completed, such that a comprehensive analysis can be done on the impact of such projects on the local and regional hydrology of the area. A good understanding of the chain of relationships that form the hydro-eco-biological and environmental cycle can be of immense help in maintaining the natural balance as we work towards exploration and exploitation of the natural resources as well as urbanization of undeveloped land. Rainfall-Runoff modeling techniques have been of great use here for decades since they provide fast and efficient means of analyzing vast amount of data that is gathered. Though process based, detailed models are better than the simple models, the later ones are used more often due to their simplicity, ease of use, and easy availability of data needed to run them. The Curve Number (CN) method developed by the United States Department of Agriculture (USDA) is one of the most widely used hydrologic modeling tools in the US, and has earned worldwide acceptance as a practical method for evaluating the effects of land use changes on the hydrology of an area. The Long-Term Hydrological Impact Assessment (L-THIA) model is a basic, CN-based, user-oriented model that has gained popularity amongst watershed planners because of its reliance on readily available data, and because the model is easy to use (http://www.ecn.purdue.edu/runoff) and produces results geared to the general information needs of planners. The L-THIA model was initially developed to study the relative long-term hydrologic impacts of different land use (past/current/future) scenarios, and it has been successful in meeting this goal. However, one of the weaknesses of L-THIA, as well as other models that focus strictly on surface runoff, is that many users are interested in predictions of runoff that match observations of flow in streams and rivers. To make L-THIA more useful for the planners and engineers alike, a simple, long-term calibration method based on linear regression of L-THIA predicted and observed surface runoff has been developed and tested here. The results from Little Eagle Creek (LEC) in Indiana show that such calibrations are successful and valuable. This method can be used to calibrate other simple rainfall-runoff models too.

Muthukrishnan, S.; Harbor, J.

2001-12-01

373

Impact of antimicrobial stewardship intervention on coagulase-negative Staphylococcus blood cultures in conjunction with rapid diagnostic testing.  

PubMed

Rapid diagnostic testing with matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) decreases the time to organism identification by 24 to 36 h compared to the amount of time required by conventional methods. However, there are limited data evaluating the impact of MALDI-TOF with real-time antimicrobial stewardship team (AST) review and intervention on antimicrobial prescribing and outcomes for patients with bacteremia and blood cultures contaminated with coagulase-negative Staphylococcus (CoNS). A quasiexperimental study was conducted to analyze the impact of rapid diagnostic testing with MALDI-TOF plus AST review and intervention for adult hospitalized patients with blood cultures positive for CoNS. Antibiotic prescribing patterns and clinical outcomes were compared before and after implementation of MALDI-TOF with AST intervention for patients with CoNS bacteremia and CoNS contamination. A total of 324 patients with a positive CoNS blood culture were included; 246 were deemed to have contaminated cultures (117 in the preintervention group and 129 in AST the intervention group), and 78 patients had bacteremia (46 in the preintervention group and 32 in the AST intervention group). No differences in demographics were seen between the groups, and similar rates of contamination occurred between the preintervention and AST intervention groups (64.3% versus 72.6%, P = 0.173). Patients with bacteremia were initiated on optimal therapy sooner in the AST intervention group (58.7 versus 34.4 h, P = 0.030), which was associated with a similarly decreased mortality (21.7% versus 3.1%, P = 0.023). Patients with CoNS-contaminated cultures had similar rates of mortality, lengths of hospitalization, recurrent bloodstream infections, and 30-day hospital readmissions, but the AST intervention group had a decreased duration of unnecessary antibiotic therapy (1.31 versus 3.89 days, P = 0.032) and a decreased number of vancomycin trough assays performed (0.88 versus 1.95, P < 0.001). In patients with CoNS bacteremia, rapid pathogen identification integrated with real-time stewardship interventions improved timely organism identification and initiation of antibiotic therapy. Patients in the AST group with blood cultures contaminated with CoNS had decreased inappropriate antimicrobial prescribing and decreased unnecessary serum vancomycin trough assays. PMID:24871213

Nagel, Jerod L; Huang, Angela M; Kunapuli, Anjly; Gandhi, Tejal N; Washer, Laraine L; Lassiter, Jessica; Patel, Twisha; Newton, Duane W

2014-08-01

374

Psychometric testing of the Impact of Event Scale-Chinese Version (IES-C) in oral cancer patients in Taiwan  

Microsoft Academic Search

Goals of work: No cultur- allyrelevantinstrumentexiststoassess the impact of cancer on patients in Taiwan. Therefore, this two-phase study was undertaken to (1) develop a Chinese version of the Impact of Event Scale (IES), (2) examine its psycho- metric properties, and (3) use the IES- Chinese version (IES-C) to assess the impact of cancer in newly diagnosed oral cancer patients in

Shu-Ching Chen; Yeur-Hur Lai; Chun-Ta Liao; Chia-Chin Lin

2005-01-01

375

A test of the longevity of impact-induced faults as preferred sites for later tectonic activity  

NASA Astrophysics Data System (ADS)

The hypothesis that impact-induced faults have been preferred sites for later deformation in response to lithospheric stresses has been suggested for several planets and satellites. This hypothesis is investigated on earth by examining whether terrestrial impact structures show higher rates of nearby earthquake activity than do surrounding intraplate regions. For 28 of 30 probable impact structures having an original crater 20 km or more in diameter, the rates of nearby seismicity have been no higher than the regional background rates. For two large probable impact structures, Vredefort and Charlevoix, with higher than normal rates of nearby seismicity, factors other than slip on impact-induced faults appear to control the occurrence of earthquakes. It is concluded that impact-induced faults, at least on earth, do not persist as lithospheric 'weak zones' for periods in excess of several million years after the impact event.

Solomon, Sean C.; Duxbury, Elizabeth D.

1987-03-01

376

A test of the longevity of impact-induced faults as preferred sites for later tectonic activity  

NASA Technical Reports Server (NTRS)

The hypothesis that impact-induced faults have been preferred sites for later deformation in response to lithospheric stresses has been suggested for several planets and satellites. This hypothesis is investigated on earth by examining whether terrestrial impact structures show higher rates of nearby earthquake activity than do surrounding intraplate regions. For 28 of 30 probable impact structures having an original crater 20 km or more in diameter, the rates of nearby seismicity have been no higher than the regional background rates. For two large probable impact structures, Vredefort and Charlevoix, with higher than normal rates of nearby seismicity, factors other than slip on impact-induced faults appear to control the occurrence of earthquakes. It is concluded that impact-induced faults, at least on earth, do not persist as lithospheric 'weak zones' for periods in excess of several million years after the impact event.

Solomon, Sean C.; Duxbury, Elizabeth D.

1987-01-01

377

The Impact of BIB-Spiralling Induced Missing Data Patterns on Goodness-of-Fit Tests in Factor Analysis. Occasional Paper OP93-1.  

ERIC Educational Resources Information Center

The impact of the use of data arising from balanced incomplete block (BIB) spiralled designs on the chi-square goodness-of-fit test in factor analysis is considered. Data from BIB designs posses a unique pattern of missing data that can be characterized as missing completely at random (MCAR). Standard approaches to factor analyzing such data rest…

Kaplan, David

378

Performance and impact on the seabed of an existing and an experimental-otterboard: Comparison between model testing and full-scale sea trials  

Microsoft Academic Search

A new door has been designed to reduce hydrodynamic drag coefficient and increase spread of door commonly used in the Mediterranean commercial demersal trawl fisheries. Flume tank testing and engineering sea trials provide data which allow us to illustrate the performance and impact on the seabed of an existing door and a new door design. In the flume tank, each

Antonello Sala; Joana d’Arc Prat Farran; Josefina Antonijuan; Alessandro Lucchetti

2009-01-01

379

The Impact of Academic Vocabulary Instruction on Reading Performance of Sophomore Students on the Florida Comprehensive Assessment Test from 2008 and 2009  

ERIC Educational Resources Information Center

This study investigated the change in sophomore reading scores on the Florida Comprehensive Assessment Test after the implementation of an academic vocabulary program and the change in teacher knowledge and professional practice after a program of staff development in academic vocabulary. The purpose was to determine if the impact of the…

McMillen, Margaret

2009-01-01

380

The Impact Analysis of Psychological Reliability of Population Pilot Study for Selection of Particular Reliable Multi-Choice Item Test in Foreign Language Research Work  

ERIC Educational Resources Information Center

The purpose of research described in the current study is the psychological reliability, its importance, application, and more to investigate on the impact analysis of psychological reliability of population pilot study for selection of particular reliable multi-choice item test in foreign language research work. The population for subject…

Fazeli, Seyed Hossein

2010-01-01

381

A methodology to condition distorted acoustic emission signals to identify fracture timing from human cadaver spine impact tests.  

PubMed

While studies have used acoustic sensors to determine fracture initiation time in biomechanical studies, a systematic procedure is not established to process acoustic signals. The objective of the study was to develop a methodology to condition distorted acoustic emission data using signal processing techniques to identify fracture initiation time. The methodology was developed from testing a human cadaver lumbar spine column. Acoustic sensors were glued to all vertebrae, high-rate impact loading was applied, load-time histories were recorded (load cell), and fracture was documented using CT. Compression fracture occurred to L1 while other vertebrae were intact. FFT of raw voltage-time traces were used to determine an optimum frequency range associated with high decibel levels. Signals were bandpass filtered in this range. Bursting pattern was found in the fractured vertebra while signals from other vertebrae were silent. Bursting time was associated with time of fracture initiation. Force at fracture was determined using this time and force-time data. The methodology is independent of selecting parameters a priori such as fixing a voltage level(s), bandpass frequency and/or using force-time signal, and allows determination of force based on time identified during signal processing. The methodology can be used for different body regions in cadaver experiments. PMID:25241279

Arun, Mike W J; Yoganandan, Narayan; Stemper, Brian D; Pintar, Frank A

2014-12-01

382

Entry Atmospheric Flight Control Authority Impacts on GN and C and Trajectory Performance for Orion Exploration Flight Test 1  

NASA Technical Reports Server (NTRS)

One of the key design objectives of NASA's Orion Exploration Flight Test 1 (EFT-1) is to execute a guided entry trajectory demonstrating GN&C capability. The focus of this paper is the ight control authority of the vehicle throughout the atmospheric entry ight to the target landing site and its impacts on GN&C, parachute deployment, and integrated performance. The vehicle's attitude control authority is obtained from thrusting 12 Re- action Control System (RCS) engines, with four engines to control yaw, four engines to control pitch, and four engines to control roll. The static and dynamic stability derivatives of the vehicle are determined to assess the inherent aerodynamic stability. The aerodynamic moments at various locations in the entry trajectory are calculated and compared to the available torque provided by the RCS system. Interaction between the vehicle's RCS engine plumes and the aerodynamic conditions are considered to assess thruster effectiveness. This document presents an assessment of Orion's ight control authority and its effectiveness in controlling the vehicle during critical events in the atmospheric entry trajectory.

McNamara, Luke W.

2012-01-01

383

Impact of HIV Testing and Counseling (HTC) Knowledge on HIV Prevention Practices Among Traditional Birth Attendants in Nigeria.  

PubMed

Nigeria is second in the world for the number of people with HIV and has a high rate of mother-to-child transmission (MTCT). Over 60% of births in Nigeria occur outside of health care facilities, and because of this, Traditional Birth Attendants (TBAs) play a significant role in maternal and child health. It is important that TBAs be knowledgeable about HIV prevention. The purpose of this study was to determine the impact of HIV testing and counseling (HTC) knowledge on the HIV prevention practices among TBAs in Nigeria. Five hundred TBAs were surveyed. Chi-square and logistic regression were used to assess differences in HIV prevention practices between TBAs with and without HTC knowledge. TBAs with HTC knowledge are significantly more likely to engage in HIV prevention practices than TBAs without HTC. Prevention practices included: wearing gloves during delivery (p < 0.01), sterilization of delivery equipment (p < 0.01), participation in blood safety training (p < 0.01), and disposal of sharps (p < 0.01). As long as a high percent of births occur outside health care facilities in Nigeria, there will be a need for TBAs. Providing TBAs with HTC training increases HIV prevention practices and can be a key to improve maternal and child health. PMID:25674783

Osuji, Alice; Pharr, Jennifer R; Nwokoro, Uche; Ike, Anulika; Ali, Christiana; Ejiro, Ogheneaga; Osuyali, John; Obiefune, Michael; Fiscella, Kevin; Ezeanolue, Echezona E

2015-01-01

384

Identification of the impacts of maintenance and testing upon the safety of LWR power plants. Final report  

SciTech Connect

The present study was designed to identify the impact of maintenance and testing (M and T) upon the safety of LWR power plants. The study involved data extraction from various sources reporting safety-related and operation-related nuclear power plant experience. Primary sources reviewed, including Licensee Event Reports (LER's) submitted to the NRC, revealed that only ten percent of events reported could be identified as M and T problems. The collected data were collated in a manner that would allow identification of principal types of problems which are associated with the performance of M and T tasks in LWR power plants. Frequencies of occurrence of events and their general endemic nature were analyzed using data clustering and pattern recognition techniques, as well as chi-square analyses for sparse contingency tables. The results of these analyses identified seven major categories of M and T error modes which were related to individual facilities and reactor type. Data review indicated that few M and T problems were directly related to procedural inadequacies, with the majority of events being attributable to human error.

Husseiny, A. A.; Sabri, Z. A.; Turnage, J. J.

1980-04-01

385

SB5 WITH THE ESTIMATED IMPACT OF LOW TEMPERATURE ALUMINUM DISSOLUTION: PRELIMINARY FRITS FOR MELT RATE TESTING  

SciTech Connect

Composition projections for Sludge Batch 5 (SB5) were developed to evaluate possible impacts of the Al-dissolution process on the availability of viable frit compositions for vitrification at the DWPF. The study included two projected SB5 compositions that bound potential outcomes (or degrees of effectiveness) of the Al-dissolution process, as well as a nominal SB5 composition projection based on the results of the recent Al-dissolution demonstration at SRNL. A Nominal Stage assessment was used to evaluate the two SB5 projections combined with an array of 19,305 frit compositions over a range of waste loading (WL) values against the DWPF process control models. The Nominal Stage results allowed for the down-selection of a small number of frits that provided reasonable projected operating windows (typically 25 to 40 wt %) and permitted some compositional flexibility (i.e., the ability to further tailor the frit to improve melt rate). Variation Stage assessments were then performed using the down-selected frits and the two SB5 composition projections with variation applied to each sludge component. The Variation Stage results showed that the operating windows were somewhat reduced in width, as expected when sludge variation is applied. Three of the down-selected frits continued to perform well for both SB5 projections through the Variation Stage, providing WL windows of approximately 26 to 35 wt %. The maximum WLs were limited by a processing constraint, TL, rather than a waste form affecting constraint (e.g., nepheline crystallization) in the Variation Stage assessments. Subsequent Nominal Stage assessments were performed with an updated SB5 projection based on the results of the Al-dissolution demonstration performed in the SRNL Shielded Cells facility (representing 40% removal of Al). The three frits identified in the earlier paper studies continued to perform well with this updated projection. The available operating windows were slightly wider, although maximum WL was limited by both the TL and nepheline constraints for all three frits. Changes in the projected SB5 composition are anticipated before processing begins at the DWPF, which will likely require additional paper study assessments as well as experimental frit development studies. This study identifies several frits which provide insight into potential operating windows for SB5 vitrification in DWPF. However, until experimental studies can be performed to gain information on melt rate and other parameters needed to optimize frit selection, no final frit recommendation can be made. Information regarding melt rate cannot be inferred from the paper study results. Experimental studies to evaluate this critical factor in DWPF processing must be performed to support frit optimization for any projected sludge composition. Five frit compositions were identified for melt rate testing at SRNL with simulated SB5 Case F SRAT product. The results of these tests will be used to evaluate the impact of the frit components--particularly B{sub 2}O{sub 3} and Na{sub 2}O--that are expected to influence melt rate for SB5-like sludges. The results of the melt rate testing will be documented in a separate report and will be used to help guide the frit recommendation process as the final SB5 composition becomes clearer.

Fox, K; Tommy Edwards, T

2008-03-11

386

A 1055 ft/sec impact test of a two foot diameter model nuclear reactor containment system without fracture  

NASA Technical Reports Server (NTRS)

A study to determine the feasibility of containing the fission products of a mobile reactor in the event of an impact is presented. The model simulated the reactor core, energy absorbing gamma shielding, neutron shielding and the containment vessel. It was impacted against an 18,000 pound reinforced concrete block at 1055 ft/sec. The model was significantly deformed and the concrete block demolished. No leaks were detected nor were any cracks observed in the model after impact.

Puthoff, R. L.

1972-01-01

387

Impact of certain household micropollutants on bacterial behavior. Toxicity tests/study of extracellular polymeric substances in sludge.  

PubMed

The impact of eight household micropollutants (erythromycin, ofloxacin, ibuprofen, 4-nonylphenol, triclosan, sucralose, PFOA and PFOS (PFAAs)) on the laboratory bacterial strain Escherichia coli MG1655 and on activated sludge from an urban wastewater treatment plant was studied. Growth-based toxicity tests on E. coli were performed for each micropollutants. The effect of micropollutants on activated sludge (at concentrations usually measured in wastewater up to concentrations disturbing the bacterial growth of E. coli) was examined in batch reactors and by comparison to a control reactor (without micropollutants). The bound extracellular polymeric substances (EPS) secreted by the sludge were measured by size exclusion chromatography and their overexpression was considered as an indicator of bacteria sensitivity to environmental changes. The chemical oxygen demand (COD) and the ammonium concentration were monitored to evaluate the biomass ability to remove the macropollution. Some micropollutants induced an increase of bound EPS in activated sludge flocs at concentrations depending on the micropollutant: erythromycin from 100 ?g/L, ofloxacin from 10 ?g/L, triclosan from 0.5 ?g/L, 4-nonylphenol from 5000 ?g/L and PFAAs from 0.1 ?g/L. This suggests that the biomass had to cope with new conditions. Moreover, at high concentrations of erythromycin (10 mg/L) and ibuprofen (5 mg/L) bacterial populations were no longer able to carry out the removal of macropollution. Ibuprofen induced a decrease of bound EPS at all the studied concentrations, probably reflecting a decrease of general bacterial activity. The biomass was not sensitive to sucralose in terms of EPS production, however at very high concentration (1 g/L) it inhibited the COD decrease. Micropollution removal was also assessed. Ibuprofen, erythromycin, ofloxacin, 4-nonylphenol and triclosan were removed from wastewater, mainly by biodegradation. Sucralose and PFOA were not removed from wastewater at all, and PFOS was slightly eliminated by adsorption on sludge. PMID:23827359

Pasquini, Laure; Merlin, Christophe; Hassenboehler, Lucille; Munoz, Jean-François; Pons, Marie-Noëlle; Görner, Tatiana

2013-10-01

388

Reliability and validity testing for the Child Oral Health Impact Profile-Reduced (COHIP-SF 19)  

PubMed Central

Objectives This study assessed the reliability and validity of the Child Oral Health Impact Profile–Short Form 19 (COHIP-SF 19) from the validated 34-item COHIP. Methods Participants included 205 pediatric, 107 orthodontic, and 863 patients with craniofacial anomalies (CFAs). Item level evaluations included examining content overlap, distributional properties, and use of the response set. Confirmatory factor analysis identified potential items for deletion. Scale reliability was assessed with Cronbach's alpha. Discriminant validity of the COHIP-SF 19 was evaluated as follows: among pediatric participants, scores were compared with varying amounts of decayed and filled surfaces (DFS) and presence of caries on permanent teeth; for orthodontic patients, scores were correlated with anterior tooth spacing/crowding; and for those with CFA, scores were compared with clinicians’ ratings of extent of defect (EOD) for nose and lip and/or speech hypernasality. Convergent validity was assessed by examining the partial Spearman correlation between the COHIP scores and a standard Global Health self-rating. Comparisons between the COHIP and the COHIP-SF 19 were completed across samples. Results The reduced questionnaire consists of 19 items: Oral Health (five items), Functional Well-Being (four items), and a combined subscale named Socio-Emotional Well-Being (10 items). Internal reliability is ?0.82 for the three samples. Results demonstrate that the COHIP-SF 19 discriminates within and across treatment groups by EOD and within a community-based pediatric sample. The measure is associated with the Global Health rating (P < 0.05), thereby indicating convergent validity. Conclusions Reliability and validity testing demonstrate that the COHIP-SF 19 is a psychometrically sound instrument to measure oral health-related quality of life across school-aged pediatric populations. PMID:22536873

Broder, Hillary L.; Wilson-Genderson, Maureen; Sischo, Lacey

2012-01-01

389

Wear of Tools Coated with Various PVD Films: Correlation with Impact Test Results by Means of FEM Simulations  

Microsoft Academic Search

The use of appropriate cutting conditions and coatings is an issue of pivotal signifi- cance since it affects the overall tool performance in manufacturing processes. This paper introduces a quick and innovative procedure for characterizing the coating cutting performance based on the film impact resistance. A correlation between coating impact resistance and cutting performance under various conditions is es- tablished.

Konstantinos-Dionysios Bouzakis; Ioannis Mirisidis; Nikolaos Michailidis; Eleftheria Lili; Anastasios Sampris; Georg Erkens; Rainer Cremer

2007-01-01

390

Test of the SHETRAN technology for modelling the impact of reforestation on badlands runoff and sediment yield at Draix, France  

Microsoft Academic Search

Physically based distributed models, such as SHETRAN, have the ability to predict the impacts of land management changes in advance of any change taking place. It needs to be shown, though, that they can deliver practical results while accounting for uncertainty in parameter evaluation. As a demonstration, SHETRAN was used to simulate the impact of reforestation on runoff and erosion

B. T Lukey; J Sheffield; J. C Bathurst; R. A Hiley; N Mathys

2000-01-01

391

General-purpose heat source: Research and development program. High-siliocon fuel characterization study: Half module impact tests 1 and 2  

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. Because any space mission could experience a launch abort or return from orbit, the heat source must be designed and constructed to survive credible accident environments. 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.; George, T.G.

1996-03-01

392

Impact of Genetic Counseling and Connexin-26 and Connexin-30 Testing on Deaf Identity and Comprehension of Genetic Test Results in a Sample of Deaf Adults: A Prospective, Longitudinal Study  

PubMed Central

Using a prospective, longitudinal study design, this paper addresses the impact of genetic counseling and testing for deafness on deaf adults and the Deaf community. This study specifically evaluated the effect of genetic counseling and Connexin-26 and Connexin-30 genetic test results on participants' deaf identity and understanding of their genetic test results. Connexin-26 and Connexin-30 genetic testing was offered to participants in the context of linguistically and culturally appropriate genetic counseling. Questionnaire data collected from 209 deaf adults at four time points (baseline, immediately following pre-test genetic counseling, 1-month following genetic test result disclosure, and 6-months after result disclosure) were analyzed. Four deaf identity orientations (hearing, marginal, immersion, bicultural) were evaluated using subscales of the Deaf Identity Development Scale-Revised. We found evidence that participants understood their specific genetic test results following genetic counseling, but found no evidence of change in deaf identity based on genetic counseling or their genetic test results. This study demonstrated that culturally and linguistically appropriate genetic counseling can improve deaf clients' understanding of genetic test results, and the formation of deaf identity was not directly related to genetic counseling or Connexin-26 and Connexin-30 genetic test results. PMID:25375116

Palmer, Christina G. S.; Boudreault, Patrick; Baldwin, Erin E.; Sinsheimer, Janet S.

2014-01-01

393

Impact of genetic counseling and Connexin-26 and Connexin-30 testing on deaf identity and comprehension of genetic test results in a sample of deaf adults: a prospective, longitudinal study.  

PubMed

Using a prospective, longitudinal study design, this paper addresses the impact of genetic counseling and testing for deafness on deaf adults and the Deaf community. This study specifically evaluated the effect of genetic counseling and Connexin-26 and Connexin-30 genetic test results on participants' deaf identity and understanding of their genetic test results. Connexin-26 and Connexin-30 genetic testing was offered to participants in the context of linguistically and culturally appropriate genetic counseling. Questionnaire data collected from 209 deaf adults at four time points (baseline, immediately following pre-test genetic counseling, 1-month following genetic test result disclosure, and 6-months after result disclosure) were analyzed. Four deaf identity orientations (hearing, marginal, immersion, bicultural) were evaluated using subscales of the Deaf Identity Development Scale-Revised. We found evidence that participants understood their specific genetic test results following genetic counseling, but found no evidence of change in deaf identity based on genetic counseling or their genetic test results. This study demonstrated that culturally and linguistically appropriate genetic counseling can improve deaf clients' understanding of genetic test results, and the formation of deaf identity was not directly related to genetic counseling or Connexin-26 and Connexin-30 genetic test results. PMID:25375116

Palmer, Christina G S; Boudreault, Patrick; Baldwin, Erin E; Sinsheimer, Janet S

2014-01-01

394

1-4244-0665-X/06/$20.00 2006 IEEE 2006 Electronics Packaging Technology Conference161 A Numerical Approach Towards the Correlation Between Ball Impact Test and Drop Reliability  

E-print Network

1-4244-0665-X/06/$20.00 ©2006 IEEE 2006 Electronics Packaging Technology Conference161 A Numerical test is developed as a package-level measure for the board-level drop reliability of solder joints a board-level drop test. In this paper, both board-level drop test and package-level ball impact test

Berlin,Technische Universität

395

The Impact of Cognitive and Psychiatric Impairment of Psychotic Disorders on the Test of Memory Malingering (TOMM)  

ERIC Educational Resources Information Center

The author analyzes the scores of inpatient psychiatric patients with varying degrees of cognitive impairment who met criteria for a psychotic disorder on the following tests: the Test of Memory Malingering (TOMM), the California Verbal Learning Test-Second Edition, Conners Continuous Performance Test-Second Edition, and the Brief Psychiatric…

Duncan, Alexander

2005-01-01

396

Impact of Patient Characteristics on Performance of Nucleic Acid Amplification Tests and DNA Probe for Detection of Chlamydia trachomatis in Women with Genital Infections  

Microsoft Academic Search

The performance of nucleic acid amplified tests (NAAT) for Chlamydia trachomatis at the cervix and in urine was examined in 3,551 women, and the impacts of clinical findings (age, endocervical and urethral inflam- mation, menses, and gonococcal coinfection) were assessed. Ligase chain reaction (LCR) and first-generation uniplex PCR were studied relative to an unamplified DNA probe (PACE2) and to an

Jeanne M. Marrazzo; Robert E. Johnson; Timothy A. Green; Walter E. Stamm; Julius Schachter; Gail Bolan; Edward W. Hook III; Robert B. Jones; David H. Martin; Carolyn M. Black

2005-01-01

397

A benchmark study of 2D and 3D finite element calculations simulating dynamic pulse buckling tests of cylindrical shells under axial impact  

SciTech Connect

A series of tests investigating dynamic pulse buckling of a cylindrical shell under axial impact is compared to several finite element simulations of the event. The purpose of the study is to compare the performance of the various analysis codes and element types with respect to a problem which is applicable to radioactive material transport packages, and ultimately to develop a benchmark problem to qualify finite element analysis codes for the transport package design industry.

Hoffman, E.L.; Ammerman, D.J.

1993-08-01

398

The impact of the Kuiper Belt Objects and of the asteroid ring on future high-precision relativistic Solar System tests  

Microsoft Academic Search

We preliminarily investigate the impact of the Kuiper Belt Objects (KBOs) and of the asteroid ring on some proposed high-precision tests of Newtonian and post-Newtonian gravity to be performed in the Solar System by means of spacecraft in heliocentric ?1AU orbits and accurate orbit determination of some of the inner planets. It turns out that the classical KBOs (CKBOs), which

Lorenzo Iorio

2007-01-01

399

Test-field for evaluation of laboratory craters using a Crater Shape-based interpolation crater detection algorithm and comparison with Martian and Lunar impact craters  

NASA Astrophysics Data System (ADS)

Impact craters are some of the most abundant geological features on most lunar and planetary bodies, providing insight into the history and physical processes that shaped their surface. It is therefore not surprising that extensive research has been done in the past on laboratory craters, as well as on crater detection algorithms (CDAs). No prior work has investigated how CDAs can assist in the research of laboratory craters, nor has an alternative formal method for evaluation of the similarity between laboratory and real impact craters been proposed. The result of this work is a test-field for evaluation of laboratory craters which includes: (1) a procedure for creation of explosion-induced laboratory craters in stone powder surfaces; (2) a method for 3D scanning of laboratory craters using a GOM-ATOS-I 3D scanner; (3) a new method for emplacement of laboratory craters into the topography of a planetary body; (4) a new method for objective evaluation of laboratory craters which utilizes the CDA, the Turing test, and a new measure of similarity between laboratory and real craters; and (5) a possibility of accompanying manual evaluation of laboratory craters using 2D topographical profiles. The successful verification of the proposed test-field, using Martian and Lunar global DEMs and local high-resolution DEMs, confirmed possibilities for the proposed scientific investigations of real impact craters using laboratory craters as proxies. This cost-effective approach also promises affordable accessibility for introductory physics and astronomy laboratories.

Salamuni?car, Goran; Lon?ari?, Sven; Vinkovi?, Dejan; Vu?ina, Damir; Gomer?i?, Mladen; Pehnec, Igor; Vojkovi?, Marin; Hercigonja, Tomislav

2012-10-01

400

Skills Testing and Disproportionate Impact: An Analysis of the Reading and Writing Test Performance of Students in the San Diego Community College District. Report 9106-M.  

ERIC Educational Resources Information Center

In 1991, a study was conducted to determine the differential effects of placement testing on cultural, linguistic, and ethnic groupings in the San Diego Community College District (SDCCD). The study was conducted in two parts. The first part examined the characteristics of the students used to norm the Comparative Guidance Program (CGP) tests used…

Armstrong, Bill; And Others

401

Impact of Proficiency Testing Program for Laboratories Conducting Early Diagnosis of HIV-1 Infection in Infants in Low- to Middle-Income Countries  

PubMed Central

A voluntary, cost-free external quality assessment (EQA) program established by the U.S. Centers for Disease Control and Prevention (CDC) was implemented to primarily monitor the performance of laboratories conducting HIV Early Infant Diagnosis (EID) from dried blood spots (DBS) in low- to middle-income countries since 2006. Ten blind DBS proficiency test (PT) specimens and 100 known HIV-positive and -negative DBS specimens (to be used as internal controls) were shipped triannually to participating laboratories with reports for the PT specimens due within 30 days. The participant's results and a summary of the performance of all participating laboratories and each diagnostic method were provided after each test cycle. Enrollment in the CDC PT program expanded progressively from 17 laboratories from 11 countries in 2006 to include 136 laboratories from 41 countries at the end of 2012. Despite external pressures to test and treat more children while expanding EID programs, mean PT test scores significantly improved over time as demonstrated by the upward trend from mid-2006 to the end of 2012 (P = 0.001) and the increase in the percentage of laboratories scoring 100% (P = 0.003). The mean test scores plateaued over the past 10 testing cycles, ranging between 98.2% and 99.7%, and discordant test results still occur but at a rate of no higher than 2.6%. Analysis of these test results suggests a positive impact of proficiency testing on the testing performance of the participating laboratories, and a continuous training program and proficiency testing participation may translate into laboratories improving their testing accuracy. PMID:24353004

Garcia, Albert; Subbarao, Shambavi; Zhang, Guoqing; Parsons, Linda; Nkengasong, John; Ou, Chin-Yih

2014-01-01

402

The Structure and Properties of Diffusion Assisted Bonded Joints in 17-4 PH, Type 347, 15-5 PH and Nitronic 40 Stainless Steels  

NASA Technical Reports Server (NTRS)

Diffusion assisted bonds are formed in 17-4 PH, 15-5 PH, type 347 and Nitronic 40 stainless steels using electrodeposited copper as the bonding agent. The bonds are analyzed by conventional metallographic, electron microprobe analysis, and scanning electron microscopic techniques as well as Charpy V-notch impact tests at temperatures of 77 and 300 K. Results are discussed in terms of a postulated model for the bonding process.

Wigley, D. A.

1981-01-01

403

Impact of Test Design, Item Quality, and Item Bank Size on the Psychometric Properties of Computer-Based Credentialing Examinations  

ERIC Educational Resources Information Center

Computer-based testing by credentialing agencies has become common; however, selecting a test design is difficult because several good ones are available - parallel forms, computer adaptive (CAT), and multistage (MST). In this study, three computer-based test designs under some common examination conditions were investigated. Item bank size and…

Xing, Dehui; Hambleton, Ronald K.

2004-01-01

404

Teaching to the Test: How No Child Left Behind Impacts Language Policy, Curriculum, and Instruction for English Language Learners  

Microsoft Academic Search

In the wake of the federal No Child Left Behind legislation, standardized tests have become increasingly high-stakes. Yet English language learners (ELLs) typically score far below native English speakers, creating pressure to “teach to the test.” This article shares findings from an intensive year long study in 10 New York City high schools, detailing how high-stakes tests become defacto language

Kate Menken

2006-01-01

405

The Impact of Test-Taking Behaviors on WISC-IV Spanish Domain Scores in Its Standardization Sample  

ERIC Educational Resources Information Center

The use of individually administered measures of intelligence and other cognitive abilities requires clinicians to monitor a client's test behaviors, given the need for a client to be engaged fully, attentive, and cooperative during the testing process. The use of standardized and norm-referenced measures of test-taking behaviors facilitates this…

Oakland, Thomas; Callueng, Carmelo; Harris, Josette G.

2012-01-01

406

Linking invasive exotic vertebrates and their ecosystem impacts in Tierra del Fuego to test theory and determine action  

NASA Astrophysics Data System (ADS)

Understanding processes and impacts of biological invasions is fundamental for ecology and management. Recent reviews summarized the mechanisms by which invasive species alter entire ecosystems, but quantitative assessments of these mechanisms are lacking for actual assemblages to determine their relative importance, frequency and patterns. We updated information on introduced vertebrates in the Tierra del Fuego Archipelago (TDF) via an exhaustive literature review and new data to evaluate ecosystem impact mechanisms and provide management recommendations. To date, 24 exotic vertebrates have naturalized in TDF, outnumbering natives nearly 2:1, with the North American beaver (Castor canadensis) and muskrat (Ondatra zibethica) being the most widely distributed species and also impacting the ecosystem through the greatest number of mechanisms. Introduced vertebrates occupied most parts of the archipelago with human-inhabited islands having greater taxa richness. All exotics potentially altered ecosystems by one or more mechanisms: 100% food webs, 92% invasional meltdown, 42% habitat modification, 38% disease or parasite transmission, 21% soil property and disturbance regime changes. Impact to habitat structure was the main clustering criterion for this assemblage. Within the species that physically alter habitats, we found two sub-groups: 1) large herbivores and 2) "others" including beavers and muskrats. Species that did not alter habitat were divided further into those with predatory trophic effects (carnivorous mammals and trout, sub-group 4) and the rest with assorted impacts (sub-group 3). By establishing high quality information on archipelago-wide assemblage, distribution, impacts and mechanisms for exotic vertebrates, we recommend, based on ecological criteria, prioritizing the management of sub-group 2. A secondary priority might be given to the carnivores in sub-group 4, while species in sub-groups 1 and 3 are less urgent. As the first systematic survey of introduced fauna on an archipelago-scale, we identified knowledge gaps, such as population abundance and dynamics for specific species, which are needed to orient future work, but the notable progress made to date is highlighted.

Valenzuela, Alejandro E. J.; Anderson, Christopher B.; Fasola, Laura; Cabello, José L.

2014-01-01

407

A test bed for investigating and evaluating the use of biometric-encoded driver licenses and their impact on law enforcement  

NASA Astrophysics Data System (ADS)

This paper describes the results of a collaborative effort between the University of New Hampshire (UNH) and the Mitretek Systems (MTS) Center for Criminal Justice Technology (CCJT). Mitretek conducted an investigation into the impact of anticipated biometrically encoded driver licenses (DLs) on law enforcement. As part of this activity, Mitretek teamed with UNH to leverage the results of UNH's Project54 and develop a pilot Driver License Interoperability Test Bed to explore both implementation and operational aspects associated with reading and authenticating biometrically encoded DLs in law enforcement scenarios. The test bed enables the exploration of new methods, techniques (both hardware and software), and standards in a structured fashion. Spearheaded by the American Association of Motor Vehicle Administrators (AAMVA) and the International Committee for Information Technology Standards Technical Group M1 (INCITS-M1) initiatives, standards involving both DLs and biometrics, respectively, are evolving at a rapid pace. In order to ensure that the proposed standards will provide for interstate interoperability and proper functionality for the law enforcement community, it is critical to investigate the implementation and deployment issues surrounding biometrically encoded DLs. The test bed described in this paper addresses this and will provide valuable feedback to the standards organizations, the states, and law enforcement officials with respect to implementation and functional issues that are exposed through exploration of actual test systems. The knowledge gained was incorporated into a report prepared by MTS to describe the anticipated impact of biometrically encoded DLs on law enforcement practice.

Messner, Richard A.; Hludik, Frank; Crowley, Todd A.; Vidacic, Dragan; Stetson, Barrett; Nadel, Lawrence D.; Nichols, Linda J.; Harris, Carol

2004-08-01

408

Flexible Residential Test Facility: Impact of Infiltration and Ventilation on Measured Cooling Season Energy and Moisture Levels  

SciTech Connect

Air infiltration and ventilation in residential buildings is a very large part of the heating loads, but empirical data regarding the impact on space cooling has been lacking. Moreover, there has been little data on how building tightness might relate to building interior moisture levels in homes in a hot and humid climate. To address this need, BA-PIRC has conducted research to assess the moisture and cooling load impacts of airtightness and mechanical ventilation in two identical laboratory homes in the hot-humid climate over the cooling season.

Parker, D.; Kono, J.; Vieira, R.; Fairey, P.; Sherwin, J.; Withers, C.; Hoak, D.; Beal, D.

2014-05-01

409

Impact of air traffic emissions on airport air quality. Multi-scale modeling, test bed and field measurements  

NASA Astrophysics Data System (ADS)

Air traffic emissions are playing a significant role in airport air quality. Engine emissions contribute to the ozone and PM formation. There is an emergence of a need to develop advanced numerical tools and airport emission databases for air pollution studies. Field monitoring at airports necessary to support model assessment is still limited in time and space. The French ONERA AIRPUR project has focused on three objectives: emission inventories; dispersion models; field measurements. Results are presented and discussed in this paper. The ground spatial distribution of LTO emissions using realistic aircraft trajectories, aircraft-engine classification by ICAO, fuel flow methodology and diurnal variations of fleet number, is presented and discussed. Exhaust species time evolution is simulated using a chemical-dispersion model. Results show high emissions of NOx during LTO, and a maximum of CO and Hydrocarbons during taxi. Depending on seasons, the NOx lifetime is varying differently; lower concentration is calculated far away from LTO emissions. Longer-lived pollutants such as ozone are formed downstream and require the use of advanced dispersion models. For this reason, two interactive models coupling the micro and the regional scales are developed and used in this work. A 3D CFD model (CEDRE) simulates the flow characteristics around buildings and the dispersion of emissions. CEDRE boundary conditions are provided by the 3D nested dispersion model MEDIUM/MM5, which includes a surface boundary layer chemistry and calculates the concentration of pollutants from the local to the airport vicinities. The CFD results show a tracer accumulation calculated downstream beside terminals, consistent with observations at some mega-airports. Sensibility studies are conducted to highlight the impact of emissions on ozone formation with MEDIUM. Results show that longer-lived species are produced downstream, their concentration depending on NOx, aromatics and VOC released by engines. Evidence of NOx regime is simulated for the ozone formation at and surrounding airports. At the boarding area, during aircraft parking, APU are generally operated for supplementary electrical power supply for cabin cooling or heating. APU emission indices of NOx, CO, HC and PM equipping civil aircraft are still badly known as they are not certified. Emission indices of soot, NOx, CO, CO2, have been measured on test bed for a specific APU consuming kerosene. Results show that APU emissions are comparable to aero-engine indices for gas, but are far more important for soot. Consequently it is expected that APU emissions are potentially important at airports. Finally, real-time continuous measurements of airborne PM, size distribution and number concentration, have been performed at Nice airport-France, along taxiways for 3 days, in summer 2003 using a 13-stage ELPI. Results show that, when road traffic emissions are not transported into the airport, the observed PM concentration does not exceed the French national threshold for PM mass in summer 2003.

Ramaroson, R.; Vuillot, F.; Durand, Y.; Courbet, B.; Janin, F.; Copalle, A.; Guin, C.; Paux, E.; Vannier, F.; Talbaut, M.; Weill, M.

2004-12-01

410

Impact of Knowledge Resources Linked to an Electronic Health Record on Frequency of Unnecessary Tests and Treatments  

ERIC Educational Resources Information Center

Introduction: Electronic knowledge resources have the potential to rapidly provide answers to clinicians' questions. We sought to determine clinicians' reasons for searching these resources, the rate of finding relevant information, and the perceived clinical impact of the information they retrieved. Methods: We asked general internists, family…

Goodman, Kenneth; Grad, Roland; Pluye, Pierre; Nowacki, Amy; Hickner, John

2012-01-01

411

Impact of the PCB design on the crack risk of CSP assemblies subjected to temperature cycling and drop tests  

Microsoft Academic Search

Especially in the handheld context, we need always greater guarantees in product efficiency. Mobiles, notebooks, organizers, cameras etc. are assets whose use increases the probability of downfall. When an electronic product drops on the ground, impact force and deformation is transferred internally to the printed circuit board (PCB), solder joints and the integrated circuits (IC) packages. The IC packages are

H. Fremont; M. Mura; B. Piano; W. Horaud; Y. Dantov

2006-01-01

412

The Impact of 1:1 Laptop Use on Middle School Math and Science Standardized Test Scores  

ERIC Educational Resources Information Center

Researchers and evaluators have been attempting to document the impact of ubiquitous or 1:1 computing on students, teachers, schools, and communities. However, the most recent reviews of research on 1:1 computing initiatives reflect a dearth of rigorous studies and emphasize the need for well-designed, scientifically based research to measure the…

Dunleavy, Matt; Heinecke, Walter F.

2008-01-01

413

Experimental test of the impacts of feral hogs on forest dynamics and processes in the southeastern US  

Microsoft Academic Search

The foraging activities of nonindigenous feral hogs (Sus scrofa) create widespread, conspicuous soil disturbances. Hogs may impact forest regeneration dynamics through both direct effects, such as consumption of seeds, or indirectly via changes in disturbance frequency or intensity. Because they incorporate litter and live plant material into the soil, hogs may also influence ground cover and soil nutrient concentrations. We

Evan Siemann; Juli A. Carrillo; Christopher A. Gabler; Roy Zipp; William E. Rogers

2009-01-01

414

The Impact of Language on the Equivalence of Trail Making Tests: Findings from Three Pediatric Cohorts with Different Language Dominance  

Microsoft Academic Search

The effect of different language backgrounds on performance and the functional equivalence of trail making tests were examined. The children's version of the Trail Making Test A and B (TMT) and the Children's Color Trails Test 1 and 2 (CCTT) were employed with right-handed (n = 79) participants. Children were classified into three groups according to language proficiency: Chinese dominant (CDL), Chinese-English

Nancy Mok; Lucia Tsang; Tatia M. C. Lee; Antolin M. Llorente

2008-01-01

415

Quasi-Static 3-Point Reinforced Carbon-Carbon Bend Test and Analysis for Shuttle Orbiter Wing Leading Edge Impact Damage Thresholds  

NASA Technical Reports Server (NTRS)

Static 3-point bend tests of Reinforced Carbon-Carbon (RCC) were conducted to failure to provide data for additional validation of an LS-DYNA RCC model suitable for predicting the threshold of impact damage to shuttle orbiter wing leading edges. LS-DYNA predictions correlated well with the average RCC failure load, and were good in matching the load vs. deflection. However, correlating the detectable damage using NDE methods with the cumulative damage parameter in LS-DYNA material model 58 was not readily achievable. The difficulty of finding internal RCC damage with NDE and the high sensitivity of the mat58 damage parameter to the load near failure made the task very challenging. In addition, damage mechanisms for RCC due to dynamic impact of debris such as foam and ice and damage mechanisms due to a static loading were, as expected, not equivalent.

Fasanella, Edwin L.; Sotiris, Kellas

2006-01-01

416

Enhanced Counseling for Women Undergoing BRCA1/2 Testing: Impact on Knowledge and Psychological Distress – Results From a Randomized Clinical Trial  

PubMed Central

This randomized controlled trial evaluated the impact of an enhanced counseling intervention on knowledge about the heritability of breast and ovarian cancer and distress, as a function of BRCA test result, among high-risk women. Before deciding about whether or not to undergo genetic testing, participants were randomly assigned to the enhanced counseling intervention (N = 69), designed to promote cognitive and affective processing of cancer risk information (following the standard individualized counseling session), or to the control condition (N = 65), which involved standard individualized counseling followed by a general health information session to control for time and attention. Women in the enhanced counseling group exhibited greater knowledge than women in the control group one week after the intervention. Further, at the affective level, the intervention was found to be most beneficial for women testing positive: specifically one week after test result disclosure, women in the intervention group who tested positive experienced lower levels of distress than women in the control group who tested positive. The findings suggest that the design of counseling aids should include a component that explicitly activates the individual's cognitive-affective processing system. PMID:20204945

Roussi, Pagona; Sherman, Kerry Anne; Buzaglo, Joanne; Daly, Mary; Taylor, Alan; Ross, Eric; Godwin, Andrew

2009-01-01

417

Practicing Accounting Profession Criterial Skills in the Classroom: A Study of Collaborative Testing and the Impact on Final Exam Scores  

ERIC Educational Resources Information Center

This mixed methods study (Creswell, 2008) was designed to test the influence of collaborative testing on learning using a quasi-experimental approach. This study used a modified embedded mixed method design in which the qualitative and quantitative data, associated with the secondary questions, provided a supportive role in a study based primarily…

VanderLaan, Ski R.

2010-01-01

418

Back on the Backburner? Impact of Reducing State-Mandated Social Studies Testing on Elementary Teachers' Instruction  

ERIC Educational Resources Information Center

Numerous studies have shown how elementary social studies instruction has been constrained or curtailed in states that do not test social studies as part of their mandated accountability system. South Carolina is a state that tests social studies as well as English, mathematics, and science in grades three through eight as part of its…

Vogler, Kenneth E.

2011-01-01

419

Soil analyses and evaluations at the impact dynamics research facility for two full-scale aircraft crash tests  

NASA Technical Reports Server (NTRS)

The aircraft structural crash behavior and occupant survivability for aircraft crashes on a soil surface was studied. The results of placement, compaction, and maintenance of two soil test beds are presented. The crators formed by the aircraft after each test are described.

Cheng, R. Y. K.

1977-01-01

420

Head and neck response of a finite element anthropomorphic test device and human body model during a simulated rotary-wing aircraft impact.  

PubMed

A finite element (FE) simulation environment has been developed to investigate aviator head and neck response during a simulated rotary-wing aircraft impact using both an FE anthropomorphic test device (ATD) and an FE human body model. The head and neck response of the ATD simulation was successfully validated against an experimental sled test. The majority of the head and neck transducer time histories received a CORrelation and analysis (CORA) rating of 0.7 or higher, indicating good overall correlation. The human body model simulation produced a more biofidelic head and neck response than the ATD experimental test and simulation, including change in neck curvature. While only the upper and lower neck loading can be measured in the ATD, the shear force, axial force, and bending moment were reported for each level of the cervical spine in the human body model using a novel technique involving cross sections. This loading distribution provides further insight into the biomechanical response of the neck during a rotary-wing aircraft impact. PMID:25085863

White, Nicholas A; Danelson, Kerry A; Gayzik, F Scott; Stitzel, Joel D

2014-11-01

421

Testing the ureilite projectile hypothesis for the El'gygytgyn impact: Determination of siderophile element abundances and Os isotope ratios in ICDP drill core samples and melt rocks  

NASA Astrophysics Data System (ADS)

The geochemical nature of the impactites from International Continental Scientific Drilling Project—El'gygytgyn lake drill core 1C is compared with that of impact melt rock fragments collected near the western rim of the structure and literature data. Concentrations of major and trace elements, with special focus on siderophile metals Cr, Co, Ni, and the platinum group elements, and isotope ratios of osmium (Os), were determined to test the hypothesis of an ureilite impactor at El'gygytgyn. Least squares mixing calculations suggest that the upper volcanic succession of rhyolites, dacites, and andesites were the main contributors to the polymict impact breccias. Additions of 2-13.5 vol% of basaltic inclusions recovered from drill core intervals between 391.6 and 423.0 mblf can almost entirely account for the compositional differences observed for the bottom of a reworked fallout deposit at 318.9 mblf, a polymict impact breccia at 471.4 mblf, and three impact melt rock fragments. However, the measured Os isotope ratios and slightly elevated PGE content (up to 0.262 ng g-1 Ir) of certain impactite samples, for which the CI-normalized logarithmic PGE signature displays a relatively flat (i.e., chondritic) pattern, can only be explained by the incorporation of a small meteoritic contribution. This component is also required to explain the exceptionally high siderophile element contents and corresponding Ni/Cr, Ni/Co, and Cr/Co ratios of impact glass spherules and spherule fragments that were recovered from the reworked fallout deposits and from terrace outcrops of the Enmyvaam River approximately 10 km southeast of the crater center. Mixing calculations support the presence of approximately 0.05 wt% and 0.50-18 wt% of ordinary chondrite (possibly type-LL) in several impactites and in the glassy spherules, respectively. The heterogeneous distribution of the meteoritic component provides clues for emplacement mechanisms of the various impactite units.

Goderis, S.; Wittmann, A.; Zaiss, J.; Elburg, M.; Ravizza, G.; Vanhaecke, F.; Deutsch, A.; Claeys, P.

2013-07-01

422

Bilateral surgical removal of impacted lower third molar teeth as a model for drug evaluation: A test with ibuprofen  

Microsoft Academic Search

It was considered that double-blind crossover studies of therapeutic efficacy after acute injury could well be done in patients who required surgical removal of impacted wisdom teeth from both sides of the lower jaw. In the present trial 24 healthy patients received either placebo or ibuprofen (Brufen®: 400 mg three times daily), a non-steroidal anti-inflammatory agent, for 5 days commencing

P. Lökken; I. Olsen; I. Bruaset; K. Norman-Pedersen

1975-01-01

423

Testing a promising homicide reduction strategy: re-assessing the impact of the Indianapolis “pulling levers” intervention  

Microsoft Academic Search

Since the publication of analyses suggesting the significant impact on youth homicide of the Boston “pulling levers” intervention,\\u000a a series of studies of similar strategies have indicated promise in reducing homicide and gun assaults. One of these studies\\u000a was an assessment of a pulling levers strategy in Indianapolis, where trend analyses indicated a significant reduction in\\u000a homicide following the intervention,