Science.gov

Sample records for impact test characteristics

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

    PubMed

    Matsui, Yasuhiro

    2014-12-01

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

  2. Evaluating the Impact of Guessing and Its Interactions with Other Test Characteristics on Confidence Interval Procedures for Coefficient Alpha

    ERIC Educational Resources Information Center

    Paek, Insu

    2016-01-01

    The effect of guessing on the point estimate of coefficient alpha has been studied in the literature, but the impact of guessing and its interactions with other test characteristics on the interval estimators for coefficient alpha has not been fully investigated. This study examined the impact of guessing and its interactions with other test…

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

    ERIC Educational Resources Information Center

    Lakin, Joni M.

    2014-01-01

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

  4. Evaluating the Impact of Releasing an Item Pool on a Test's Empirical Characteristics.

    PubMed

    Buckendahl, Chad W; Gerrow, Jack D

    2016-10-01

    Protecting the security of examination questions is an important task for high-stakes examining boards/agencies and university programs. To maintain the security of questions, examining boards and university programs use a combination of prevention, detection, and enforcement strategies. A common prevention strategy is to establish a number of controls on access to questions; however, restricting access can motivate examinees to try harder to reconstruct questions that may appear on future versions of the test. Moreover, access to study materials by some groups and not others can present a challenge to the fairness of examinations. The aim of this study was to evaluate the empirical stability of test characteristics. Specifically, the primary research objective was to investigate the empirical stability of the items and test forms of a written examination before and after a specific policy decision was implemented. As a response to both of these concerns, this article describes a study that evaluated how psychometric (i.e., statistical) properties of test forms and individual questions might be affected by publicly releasing a larger number of questions from an item question pool. A series of analyses were conducted, including item drift to evaluate stability of the characteristics. The results suggest that empirical characteristics of the test forms and individual questions have remained relatively stable since the release policy was implemented. Specifically, statistical properties of the test forms have continued to perform similarly to test forms that were constructed prior to the release. Although the results of this study were promising, the context of this specific testing program may have offered additional protections such as a limited number of administrations that others may not. Therefore, testing/examining agencies and university programs may want to consider this strategy with appropriate caution.

  5. Sink characteristics of a full-scale environmental chamber and their impact on material emission testing

    SciTech Connect

    Zhang, J.S.; Nong, G.; Shaw, C.Y.

    1999-07-01

    In this study, a method was developed and used to measure the adsorption/desorption characteristics (i.e., the so-called sink effect) of a full-scale environmental chamber (5m x 4m x 2.75m high). Unrecovered and reversible sink parameters were measured for five volatile organic compounds (VOCs): ethylbenzene, decane, 1,2-dichlorobenzene, octanol, and dodecane. It was found that for the five compounds tested, the full-scale chamber had noticeable reversible sink effect but negligible unrecovered sink effect. The reversible sink strength increased in the order of ethylbenzene, decane, 1,2-dichlorobenzene, dodecane, and octanol. A first-order reversible sink model appeared to be adequate for describing the adsorption/desorption characteristics of the chamber. It was also found that when the return air was recirculated through heating and cooling coils and HEPA filter, the sink strength increased significantly. The reversible sink effect was more noticeable in testing wet coating materials rather than dry materials. The results of this study would be useful for developing standard test methods and procedures for evaluating the performance of full-scale environmental chambers and for using such chambers to test and investigate VOC emissions from building materials and furnishings.

  6. Testing the Impact of Child Characteristics × Instruction Interactions on Third Graders’ Reading Comprehension by Differentiating Literacy Instruction

    PubMed Central

    Connor, Carol McDonald; Morrison, Fredrick J.; Fishman, Barry; Giuliani, Sarah; Luck, Melissa; Underwood, Phyllis S.; Bayraktar, Aysegul; Crowe, Elizabeth C.; Schatschneider, Christopher

    2016-01-01

    There is accumulating correlational evidence that the effect of specific types of reading instruction depends on children’s initial language and literacy skills, called child characteristics × instruction (C×I) interactions. There is, however, no experimental evidence beyond first grade. This randomized control study examined whether C×I interactions might present an underlying and predictable mechanism for explaining individual differences in how students respond to third-grade classroom literacy instruction. To this end, we designed and tested an instructional intervention (Individualizing Student Instruction [ISI]). Teachers (n = 33) and their students (n = 448) were randomly assigned to the ISI intervention or a vocabulary intervention, which was not individualized. Teachers in both conditions received professional development. Videotaped classroom observations conducted in the fall, winter, and spring documented the instruction that each student in the classroom received. Teachers in the ISI group were more likely to provide differentiated literacy instruction that considered C×I interactions than were the teachers in the vocabulary group. Students in the ISI intervention made greater gains on a standardized assessment of reading comprehension than did students in the vocabulary intervention. Results indicate that C×I interactions likely contribute to students’ varying response to literacy instruction with regard to their reading comprehension achievement and that the association between students’ profile of language and literacy skills and recommended instruction is nonlinear and dependent on a number of factors. Hence, dynamic and complex theories about classroom instruction and environment impacts on student learning appear to be warranted and should inform more effective literacy instruction in third grade. PMID:27867226

  7. Testing the Impact of Child Characteristics × Instruction Interactions on Third Graders' Reading Comprehension by Differentiating Literacy Instruction.

    PubMed

    Connor, Carol McDonald; Morrison, Fredrick J; Fishman, Barry; Giuliani, Sarah; Luck, Melissa; Underwood, Phyllis S; Bayraktar, Aysegul; Crowe, Elizabeth C; Schatschneider, Christopher

    2011-01-01

    There is accumulating correlational evidence that the effect of specific types of reading instruction depends on children's initial language and literacy skills, called child characteristics × instruction (C×I) interactions. There is, however, no experimental evidence beyond first grade. This randomized control study examined whether C×I interactions might present an underlying and predictable mechanism for explaining individual differences in how students respond to third-grade classroom literacy instruction. To this end, we designed and tested an instructional intervention (Individualizing Student Instruction [ISI]). Teachers (n = 33) and their students (n = 448) were randomly assigned to the ISI intervention or a vocabulary intervention, which was not individualized. Teachers in both conditions received professional development. Videotaped classroom observations conducted in the fall, winter, and spring documented the instruction that each student in the classroom received. Teachers in the ISI group were more likely to provide differentiated literacy instruction that considered C×I interactions than were the teachers in the vocabulary group. Students in the ISI intervention made greater gains on a standardized assessment of reading comprehension than did students in the vocabulary intervention. Results indicate that C×I interactions likely contribute to students' varying response to literacy instruction with regard to their reading comprehension achievement and that the association between students' profile of language and literacy skills and recommended instruction is nonlinear and dependent on a number of factors. Hence, dynamic and complex theories about classroom instruction and environment impacts on student learning appear to be warranted and should inform more effective literacy instruction in third grade.

  8. Impact Tests for Woods

    NASA Technical Reports Server (NTRS)

    1922-01-01

    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.

  9. Characteristics of Impact Diamonds

    NASA Astrophysics Data System (ADS)

    Skala, R.; Bouska, V. J.

    1992-07-01

    Having studied two Czech diamonds in UV light (lambda=366 nm) they appeared to be an extraordinary dirty orange color [1], the same as in the case of Popigai and ureilites impact diamonds (ID) [2]. SEM images show evidence of a thatch-like surface that is very similar to that of the Abee chondrite [3]. Commonly, the ID contain microscopic black plates which are formed by graphite or a carbon matter with indefinite structure, and they are always associated with hexagonal moissanite [2,4]. One unexplained fact is connected with a fabric of the ID aggregates, i.e. both Czech diamonds are single crystals, otherwise other ID form polycrystalline strongly textured aggregates. [1] Bouska V.J. and Skala R.M. (1992) Abstracts for International Conference on Large Meteorite Impacts and Planetary Evolution, in press. [2] Masaitis V.L., Shafranovskii G.I., Ezerskii V.A., and Reshetnyak N.B. (1990) Meteoritica 49, 180-196. [3] Russell S.S. and Pillinger C.T. (1991) Abstracts 54th Ann. Meet. Meteor. Soc. 200. [4] Bauer J., Fiala J., and Hrichova R. (1963) Amer. Mineral. 48, 620-634.

  10. HIV Testing Characteristics Among Hispanic Adolescents.

    PubMed

    Ma, Mindy; Malcolm, Lydia; Diaz-Albertini, Kristine; Klinoff, Vera A

    2016-02-01

    Hispanic adolescents are disproportionally impacted by HIV/AIDS. Among Hispanic people living with HIV, delayed testing and late entry into HIV care have been documented. The current study examined Hispanic adolescents' HIV testing characteristics and factors related to testing. Adolescents aged 13-16 (N = 223) completed a survey on HIV testing motivation, perceptions, and experience, sexual behavior, and substance use. Results indicate few adolescents (9%) had taken an HIV test. Among those who have not been tested, 32.5% expressed interest in testing. HIV testing was favorably perceived with 82.4% reported testing should be done with all youth or those are sexually active. Adolescents who had engaged in high risk behaviors (history of sexual intercourse, substance use) were more likely to have been tested or to express interest in testing. Given that HIV testing is positively perceived by Hispanic adolescents, prevention efforts should focus on minimizing barriers and enhancing accessibility to HIV screening.

  11. Measuring space radiation impact on the characteristics of optical glasses; measurement results and recommendations from testing a selected set of materials

    NASA Astrophysics Data System (ADS)

    Fruit, Michel; Gusarov, Andrei I.; Doyle, Dominic B.

    2002-09-01

    Radiation sensitivity of glass is a general concern for the designer of Space optical instruments. ASTRIUM, in cooperation with SCK-CEN, has conducted a study (under ESA sponsorship) to define the approach for the gathering of a comprehensive database to quantify these effects through the use of linear sensitivity coefficients (called "Dose Coefficients"). These "Dose coefficients" cover not only transmittance but also other characteristics such as refractive index. After having recalled the basics of the proposed approach, results of the first irradiation tests which have been run on a selected set of classical glasses nd their Radiation hardened Cerium doped analogs (including BK7, K5, LaK9 and other Schott glasses) will be discussed. PRotons and gamma radiation have been performed with the aim to demonstrate equivalence, thus allowing to further considering only gamma radiation for an extensive testing of available glasses. Relaxation impacts on some months period have been tentatively analyzed. All these measurements have been processed and the modeling approach of the radiations impacts has been derived, as shown in the publication from A. Gusarov at this conference. This will constitute the grounds for the building of a comprehensive "Dose Coefficients" data base, as expressed in the publication from D. Doyle also at this conference. From this, recommendations for a sound characterization of radiation impacts on refractive optical materials have been established and are the subject of this publication.

  12. Testing the Impact of Child Characteristics x Instruction Interactions on Third Graders' Reading Comprehension by Differentiating Literacy Instruction

    ERIC Educational Resources Information Center

    Connor, Carol McDonald; Morrison, Fredrick J.; Fishman, Barry; Giuliani, Sarah; Luck, Melissa; Underwood, Phyllis S.; Bayraktar, Aysegul; Crowe, Elizabeth C.; Schatschneider, Christopher

    2011-01-01

    There is accumulating correlational evidence that the effect of specific types of reading instruction depends on children's initial language and literacy skills, called child characteristics x instruction (CxI) interactions. There is, however, no experimental evidence beyond first grade. This randomized control study examined whether CxI…

  13. Southern Impact Testing Alliance (SITA)

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  14. Testing Impact?s Radiation Code

    SciTech Connect

    Edis, T; Cameron-Smith, P; Grant, K E; Bergmann, D; Chuang, C C

    2004-07-12

    This is a summary of work done over an 8 week period from May to July 2004, which concerned testing the longwave and shortwave radiation packages in Impact. The radiation code was initially developed primarily by Keith Grant in the context of LLNL's 2D model, and was added to Impact over the last few summers. While the radiation code had been tested and also used in some aerosol-related calculations, its 3D form in Impact had not been validated with comparisons to satellite data. Along with such comparisons, our work described here was also motivated by the need to validate the radiation code for use in the SciDAC consortium project. This involved getting the radiation code working with CAM/WACCM met data, and setting the stage for comparing CAM/WACCM radiation output with Impact results.

  15. Hypervelocity impact testing of tethers

    NASA Technical Reports Server (NTRS)

    Woodis, William R.; Tallentire, Francis I.

    1988-01-01

    An experimental test program has been conducted to ascertain the strength losses to which representative space tether materials may be prone upon impact by hypervelocity particles of known size, density, and velocity, when the tether is under tensile loading typical of flight design loads. Twelve hypervelocity impacts were followed by tensile tests to failure to determine residual strength; relationships are established between particle velocity and strength loss due to impact damage, as well as between tether strength loss and the relationship between particle and tether diameters. Tentative design criteria are formulated in terms of a design factor allowing for strength degradation by impact.

  16. Impact Testing of Stainless Steel Materials

    SciTech Connect

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

    2005-07-01

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

  17. Nickel: Impact on horticultural characteristics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Knowledge by practitioners regarding the potential impact of nickel nutritional physiology on pecan orchard profitability is a limiting factor in optimization of physiological efficiency of orchard enterprises. Knowledge by farmers and extension specialists about the role of nickel, a newly recogni...

  18. Impacting device for testing insulation

    NASA Technical Reports Server (NTRS)

    Redmon, J. W. (Inventor)

    1984-01-01

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

  19. Characteristic evaluation of CFRP composites under falling weight impact loading

    NASA Astrophysics Data System (ADS)

    Im, K. H.; Park, N. S.; Hsu, D. K.; Kim, S. K.; Park, J. W.; Yang, I. Y.

    2002-05-01

    This paper describes a method for a falling weight impact test to estimate the impact energy absorbing characteristics and impact strength of carbon-fiber reinforced plastics (CFRP) laminate plates based on considerations of stress wave propagation theory, which were converted to measurements of load and displacement verses time. The delamination area of impacted specimens for the different ply orientations was measured with an ultrasonic C-scanner to determine the correlation between impact energy and delamination area. The energy absorbed by a quasi-isotropic specimen having four interfaces was higher than that of orthotropic laminates with two interfaces. The more interfaces, the greater the energy absorbed. The absorbed energy of a hybrid specimen containing a CFRP layer was higher than that of normal specimens. Also, a falling weight impact tester was built to evaluate the characteristics and impact strength of CFRPs.

  20. Survey of receiving-water environmental impacts associated with discharges from pulp mills; 1: Mill characteristics, receiving-water chemical profiles and lab toxicity tests

    SciTech Connect

    Robinson, R.D. . Dept. of Environmental Biology); Carey, J.H. . Rivers Research Branch); Solomon, K.R. ); Smith, I.R. . Water Resources Branch); Servos, M.R.; Munkittrick, K.R. . Great Lakes Lab. for Fisheries and Aquatic Sciences)

    1994-07-01

    This survey examined the relationship between environmental responses at pulp mill sites and the pulping process, effluent treatment, and bleaching technology used by pulp mills. This manuscript is the first in a series of four; it reviews the location and operating characteristics of mills included in the survey and provides background information on water chemistry that is relevant to the other components of the survey. In addition, lab 7-d toxicity tests of receiving water were conducted using fathead minnows (Pimephales promelas) and the cladoceran Ceriodaphnia dubia with water samples collected upstream and downstream of effluent discharges at 11 Canadian pulp and paper mills; these samples were collected at the same time as fish surveys were conducted. Survival of fathead minnow larvae was significantly reduced at four of the 11 downstream sites. Ceriodaphnia reproduction was significantly higher at six of the 11 downstream sites and significantly lower at two downstream sites. There were no significant effects on fathead minnow larva growth or adult Ceriodaphnia survival at any of the examined downstream sites. Negative effects in the toxicity tests were generally associated with the low dilution discharge of primary treated effluent with a previous history of acute toxicity. Fathead minnow and Ceriodaphnia tests were generally correlated with historical data on benthic macroinvertebrate community responses. Neither toxicity test predicted the physiological changes in wild fish that are presented in accompanying papers.

  1. Glatz Prototype Seat Impact Testing

    DTIC Science & Technology

    2013-07-03

    all PH testing. The HIA consists of a 4 ft by 8 ft sled positioned on a 204 ft long track and is accelerated using a 24 inch diameter pneumatic ...thrust piston, the sled coasts to a stop or is stopped with a triggered pneumatic brake system. The impact acceleration is roughly sinusoidal. HIA... Hybrid III Aerospace manikin (HB50) representing a mid-sized male, and a Large Anthropomorphic Research Device (LARD) manikin representing a large male

  2. Nurse work engagement impacts job outcome and nurse-assessed quality of care: model testing with nurse practice environment and nurse work characteristics as predictors

    PubMed Central

    Van Bogaert, Peter; van Heusden, Danny; Timmermans, Olaf; Franck, Erik

    2014-01-01

    Aim: To explore the mechanisms through which nurse practice environment dimensions, such as nurse–physician relationship, nurse management at the unit level and hospital management and organizational support, are associated with job outcomes and nurse-assessed quality of care. Mediating variables included nurse work characteristics of workload, social capital, decision latitude, as well as work engagement dimensions of vigor, dedication and absorption. Background: Understanding how to support and guide nurse practice communities in their daily effort to answer complex care most accurate, alongside with the demand of a stable and healthy nurse workforce, is challenging. Design: Cross-sectional survey. Method: Based on earlier empirical findings, a structural equation model, designed with valid measurement instruments, was tested. The study population included registered acute care hospital nurses (N = 1201) in eight hospitals across Belgium. Results: Nurse practice environment dimensions predicted nurses’ ratings of job outcome variables as well as quality of care. Features of nurses’ work characteristics, e.g., perceived workload, decision latitude, social capital, and the three dimension of work engagement, played mediating roles between nurse practice environment and outcomes. A revised model, using various fit measures, explained 60% of job outcomes and 47% of nurse-assessed quality of care. Conclusion: The findings in this study show that nurse work characteristics as workload, decision latitude, and social capital, alongside with nurse work engagement (e.g., vigor, dedication, and absorption) influence nurses’ perspective of their nurse practice environment, job outcomes, and quality of care. The results underline aspects to considerate for various stakeholders, such as executives, nurse managers, physicians, and staff nurses, in setting up and organizing health care services. PMID:25431563

  3. Impact of human emotions on physiological characteristics

    NASA Astrophysics Data System (ADS)

    Partila, P.; Voznak, M.; Peterek, T.; Penhaker, M.; Novak, V.; Tovarek, J.; Mehic, Miralem; Vojtech, L.

    2014-05-01

    Emotional states of humans and their impact on physiological and neurological characteristics are discussed in this paper. This problem is the goal of many teams who have dealt with this topic. Nowadays, it is necessary to increase the accuracy of methods for obtaining information about correlations between emotional state and physiological changes. To be able to record these changes, we focused on two majority emotional states. Studied subjects were psychologically stimulated to neutral - calm and then to the stress state. Electrocardiography, Electroencephalography and blood pressure represented neurological and physiological samples that were collected during patient's stimulated conditions. Speech activity was recording during the patient was reading selected text. Feature extraction was calculated by speech processing operations. Classifier based on Gaussian Mixture Model was trained and tested using Mel-Frequency Cepstral Coefficients extracted from the patient's speech. All measurements were performed in a chamber with electromagnetic compatibility. The article discusses a method for determining the influence of stress emotional state on the human and his physiological and neurological changes.

  4. Characteristic temperatures of hypervelocity dust impact plasmas

    NASA Astrophysics Data System (ADS)

    Collette, A.; Malaspina, D. M.; Sternovsky, Z.

    2016-09-01

    The effective ion and electron temperatures of dust impact generated plasma clouds are measured experimentally as a function of impact speed in the range of 4-20 km/s. The measurements are performed in an experimental setup that resembles the detection of dust particles by electric field or plasma wave antennas on spacecraft. The spacecraft is modeled as a conductive plate and a cylindrical antenna connected to voltage follower electronics is used to measure the collected charge. The setup is bombarded with dust particles using the University of Colorado IMPACT dust accelerator facility. The effective ion and electron temperatures are determined from the variation of the impact signals with an applied bias voltage. The results show that the temperatures of the electrons remain at around or below 5 eV over the investigated impact speed range. The characteristic ion temperature is about 5 eV at 4 km/s; however, it increases with increasing impact speed to > 10 eV at 20 km/s. Given that the floating potentials of spacecraft and antennas are on the order of a few volts, the findings suggest that any model for the interpretation of dust impact signals should take into account the effects of a finite temperatures.

  5. High Pressure Quick Disconnect Particle Impact Tests

    NASA Technical Reports Server (NTRS)

    Rosales, Keisa R.; Stoltzfus, Joel M.

    2009-01-01

    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

  6. Supersonic Particle Impact Test Capabilities: Investigative Report

    NASA Technical Reports Server (NTRS)

    Rosales, Keisa

    2007-01-01

    NASA Johnson Space Center White Sands Test Facility (WSTF) performed particle impact flow tests to determine the maximum capabilities of the particle impact test systems in different configurations. Additional flow tests were performed to determine the target pressures at given upstream conditions to supplement the WSTF data located in ASTM Manual 36 (2000).

  7. High Pressure Quick Disconnect Particle Impact Tests

    NASA Technical Reports Server (NTRS)

    Peralta, Stephen; Rosales, Keisa; Smith, Sarah R.; Stoltzfus, Joel M.

    2007-01-01

    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), NASA Johnson Space Center requested White Sands Test Facility (WSTF) to perform particle impact testing. Testing was performed from November 2006 through May 2007 and included standard supersonic and subsonic particle impact tests on 15-5 PH stainless steel, as well as tests performed on a QD simulator. This report 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.

  8. Examining the Impact of Drifted Polytomous Anchor Items on Test Characteristic Curve (TCC) Linking and IRT True Score Equating. Research Report. ETS RR-12-09

    ERIC Educational Resources Information Center

    Li, Yanmei

    2012-01-01

    In a common-item (anchor) equating design, the common items should be evaluated for item parameter drift. Drifted items are often removed. For a test that contains mostly dichotomous items and only a small number of polytomous items, removing some drifted polytomous anchor items may result in anchor sets that no longer resemble mini-versions of…

  9. 30 CFR 7.46 - Impact test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Impact test. 7.46 Section 7.46 Mineral... MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.46 Impact test. (a) Test... individual cells. At the test temperature range of 65 °F -80 °F (18.3 °C-26.7 °C), apply a dynamic force...

  10. 30 CFR 7.46 - Impact test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Impact test. 7.46 Section 7.46 Mineral... MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.46 Impact test. (a) Test... individual cells. At the test temperature range of 65 °F -80 °F (18.3 °C-26.7 °C), apply a dynamic force...

  11. 30 CFR 7.46 - Impact test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Impact test. 7.46 Section 7.46 Mineral... MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.46 Impact test. (a) Test... individual cells. At the test temperature range of 65 °F -80 °F (18.3 °C-26.7 °C), apply a dynamic force...

  12. Hypervelocity impact testing of cables

    NASA Technical Reports Server (NTRS)

    Jex, D. W.; Adkinson, A. B.; English, J. E.; Linebaugh, C. E.

    1973-01-01

    The physics and electrical results obtained from simulated micrometeoroid testing of certain Skylab cables are presented. The test procedure, electrical circuits, test equipment, and cable types utilized are also explained.

  13. Impact of Test Disclosure Legislation on Test Development.

    ERIC Educational Resources Information Center

    Fremer, John

    Test disclosure legislation in New York State (LaValle Act) has had a major impact on the national testing programs administered by Educational Testing Services (ETS) for various sponsoring organizations. The paper reviews the immediate operational effects of test disclosure in the following areas: (1) increase in number of test forms developed;…

  14. Solid rocket booster water impact test

    NASA Technical Reports Server (NTRS)

    Bugg, F.

    1982-01-01

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

  15. Water impact shock test system

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The basic objective was to design, manufacture, and install a shock test system which, in part, would have the ability to subject test articles weighing up to 1,000 pounds to both half sine and/or full sine pulses having peak levels of up to 50 G's with half sine pulse durations of 100 milliseconds or full sine period duration of 200 milliseconds. The tolerances associated with the aforementioned pulses were +20% and -10% for the peak levels and plus or minus 10% for the pulse durations. The subject shock test system was to be capable of accepting test article sizes of up to 4 feet by 4 feet mounting surface by 4 feet in length.

  16. Salient Characteristics for Terrestrial Analog Engineering Test Sites

    NASA Technical Reports Server (NTRS)

    Watson, J.K.; Blaisdell, G. L.

    2000-01-01

    The use of terrestrial analog sites is an essential component of the development process for systems that are planned for lunar and planetary surfaces. These sites can also be valuable for training personnel who are expected to operate those systems. The fact that the site is an integral element, capable of influencing data and impacting test results, must not be overlooked. For tests performed in analog environments to be truly valid it is essential that the relevant characteristics of the employed sites be thoroughly understood. It is also critical that a comparative evaluation be made to assess the similarity of the analog sites to target planetary sites. Examples of relevant characteristics include terrain, soil properties, meteorology, geologic features, biological history, and remoteness. The importance of each of the characteristics varies with the type of extraterrestrial activity to be conducted. As a result, a site that is ideal for one purpose may be totally inadequate for another. It may also be appropriate to utilize multiple sites of increasing fidelity as the development process evolves. For example, early in the development process, the use of lower-fidelity sites may be elected - especially if they are available for a lower cost. Later, it may be necessary to employ higher-fidelity sites to capture greater realism, even if there is an associated increased cost. Finally, when interpreting the results of field tests, it is necessary to understand the sensitivity of the results to the relevant conditions. Knowledge of characteristics and sensitivity of results is particularly important when using field test results to validate analytical model predictions. This is especially true for activities that involve physical interaction with the site. Examples would include tests of rovers or other vehicles and associated trafficability modeling, spacesuit mobility tests, and tests associated with system deployment operations.

  17. 30 CFR 7.46 - Impact test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.46 Impact test. (a) Test... at 122 °F (50 °C) for a period of 48 hours. (2) Mount the covers on a battery box of the same design with which the covers are to be approved, including any support blocks, with the battery...

  18. Permeability After Impact Testing of Composite Laminates

    NASA Technical Reports Server (NTRS)

    Nettles, A.T.; Munafo, Paul (Technical Monitor)

    2002-01-01

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

  19. Permeability After Impact Testing of Composite Laminates

    NASA Technical Reports Server (NTRS)

    Nettles, Alan T.

    2003-01-01

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

  20. Impact testing of textile composite materials

    NASA Technical Reports Server (NTRS)

    Portanova, Marc

    1995-01-01

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

  1. DebriSat Hypervelocity Impact Test

    DTIC Science & Technology

    2015-08-01

    10. SPONSOR/MONITOR’S ACRONYM(S) NASA Orbital Debris Program Office Attn: Dr. J.C. Liou 2101 NASA Parkway Houston, TX 77058 11. SPONSOR...of providing information on the physics of the entire impact event. 15. Subject Terms Orbital debris ; light gas gun; AEDC Range G; hypervelocity...based on the 1992 Satellite Orbital Debris Characterization Impact Test (SOCIT) project in the AEDC Range G facility (Ref. 1). This previous test

  2. Wave velocity characteristic for Kenaf natural fibre under impact damage

    NASA Astrophysics Data System (ADS)

    Zaleha, M.; Mahzan, S.; Fitri, Muhamad; Kamarudin, K. A.; Eliza, Y.; Tobi, A. L. Mohd

    2017-01-01

    This paper aims to determining the wave velocity characteristics for kenaf fibre reinforced composite (KFC) and it includes both experimental and simulation results. Lead zirconate titanate (PZT) sensor were proposed to be positioned to corresponding locations on the panel. In order to demonstrate the wave velocity, an impacts was introduced onto the panel. It is based on a classical sensor triangulation methodology, combines with experimental strain wave velocity analysis. Then the simulation was designed to replicate panel used in the experimental impacts test. This simulation was carried out using ABAQUS. It was shown that the wave velocity propagates faster in the finite element simulation. Although the experimental strain wave velocity and finite element simulation results do not match exactly, the shape of both waves is similar.

  3. Hypervelocity impact testing of spacecraft optical sensors

    SciTech Connect

    1995-07-01

    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.

  4. Tests of the Giant Impact Hypothesis

    NASA Technical Reports Server (NTRS)

    Jones, J. H.

    1998-01-01

    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.

  5. Damage Characteristics and Residual Strength of Composite Sandwich Panels Impacted with and Without Compression Loading

    NASA Technical Reports Server (NTRS)

    McGowan, David M.; Ambur, Damodar R.

    1998-01-01

    The results of an experimental study of the impact damage characteristics and residual strength of composite sandwich panels impacted with and without a compression loading are presented. Results of impact damage screening tests conducted to identify the impact-energy levels at which damage initiates and at which barely visible impact damage occurs in the impacted facesheet are discussed. Parametric effects studied in these tests include the impactor diameter, dropped-weight versus airgun-launched impactors, and the effect of the location of the impact site with respect to the panel boundaries. Residual strength results of panels tested in compression after impact are presented and compared with results of panels that are subjected to a compressive preload prior to being impacted.

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

    NASA Astrophysics Data System (ADS)

    Guruprasad, Pradosh

    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.

  7. FOD impact testing of composite fan blades

    NASA Technical Reports Server (NTRS)

    Johns, R. H.

    1974-01-01

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

  8. FOD impact testing of composite fan blades

    NASA Technical Reports Server (NTRS)

    Johns, R. H.

    1974-01-01

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

  9. Impact testing on composite fan blades

    NASA Technical Reports Server (NTRS)

    Johns, R. H.

    1974-01-01

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

  10. Mechanical Impact Testing: A Statistical Measurement

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  11. Responses of side impact dummies in sled tests.

    PubMed

    Yoganandan, Narayan; Pintar, Frank A

    2005-05-01

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

  12. Impact Testing of Stainless Steel Material at Cold Temperatures

    SciTech Connect

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

    2008-07-01

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

  13. Impact Response Characteristics of Polymeric Materials

    DTIC Science & Technology

    1981-11-01

    effort were (1) to measure the impact pulse produced when these poly- mers are struck at velocities up to the highest value feasible using a compressed...the first arrival of the impact signal at the sensor, and some basis for defining its initial shape, are essential to translating the pulse...phenomena are involved. At the start the work was done mainly by driving the spherical bodies into the polymers at constant speed over the velocity range

  14. Modelling the impact testing of prescription lenses.

    PubMed

    McAuliffe, P J; Truss, R W; Pittolo, M

    1997-04-01

    Lenses are tested in an impact test in which a steel ball is dropped from a height onto the centre of the lens. This causes the lens to deform until the stress in the lens reaches a point at which fracture occurs. A survey of the literature was carried out and analytical models of the load/deflection and of the deflection/stress relationships were selected. A mathematical model of the impact test on lenses was developed. This model consisted of calculating the load-deflection relationship of a lens loaded at a central point, combined with calculating the deflection at which fracture occurred. From this model the impact energy required to deform a lens to fracture was obtained. This was held to be equal to the minimum kinetic energy of an impactor, less losses, that would be needed to cause lens fracture. As the losses are small, the calculated energy was used as an estimate of the impact strength of the lens. These values were then compared to those established by experiment. The impact energies predicted by the model were a close approximation of the experimental results for the lenses tested.

  15. The Factor Structure of Test Task Characteristics and Examinee Performance

    ERIC Educational Resources Information Center

    Carr, Nathan T.

    2006-01-01

    The present study focuses on the task characteristics of reading passages and key sentences in a test of second language reading. Using a new methodological approach to describe variation in test task characteristics and explore how differences in these characteristics might relate to examinee performance, it posed the two following research…

  16. Impact Testing of a Stirling Converter's Linear Alternator

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

    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.

  17. New impact sensitivity test of liquid explosives

    NASA Astrophysics Data System (ADS)

    Tiutiaev, Andrei; Trebunskih, Valeri

    The sensitivity of liquid explosive in the presence of gas bubbles increases many times as compared with the liquid without gas bubbles. Local hot spot in this case formed as a result of compression and heating of the gas inside the bubbles. If we consider that in the liquid as a result of convection, wave motion, shock, etc. gas bubbles are easily generated, the need to develop a method for determining sensitivity of liquid explosives to impact and a detailed study of the ignition explosives with bubbles is obvious. On a mathematical model of a single steam bubbles in the fluid theoretically considered the process of initiating explosive liquid systems to impact. For the experimental investigation, the well-known K-44 -II with the metal cap were used. Instead of the metal cap in the standard method in this paper there was polyurethane foam cylindrical container with LHE, which is easily deforms by impact. A large number of tests with different liquid explosives were made. It was found that the test LHE to impact with polyurethane foam to a large extent reflect the real mechanical sensitivity due to the small loss of impact energy on the deformation of the metal cap, as well as the best differentiation LHE sensitivity due to the higher resolution method . Results obtained in the samara state technical university.

  18. Impact sensitivity test of liquid explosives

    NASA Astrophysics Data System (ADS)

    Tiutiaev, Andrei; Trebunskih, Valeri; Dolzhikov, Andrei; Zvereva, Irina

    2015-06-01

    The sensitivity of liquid explosive in the presence of gas bubbles increases many times as compared with the liquid without gas bubbles. If we consider that in the liquid as a result of convection, wave motion, shock, etc. gas bubbles are easily generated, the need to develop a method for determining sensitivity of liquid explosives to impact and a detailed study of the ignition explosives with bubbles is obvious. On a mathematical model of a single steam bubbles in the fluid theoretically considered the process of initiating explosive liquid systems to impact. For the experimental investigation, the well-known K-44 -II and the so-called appliance No. 1 were used. Instead of the metal cap in the standard method in this paper there was polyurethane foam cylindrical container with LHE, which is easily deforms by impact. A large number of tests with different liquid explosives were made. It was found that the test LHE to impact in appliance No. 1 with polyurethane foam to a large extent reflect the real mechanical sensitivity due to the small loss of impact energy on the deformation of the metal cap, as well as the best differentiation LHE sensitivity due to the higher resolution method .

  19. Impact Tensile Testing of Stainless Steels at Various Temperatures

    SciTech Connect

    D. K. Morton

    2008-03-01

    Stainless steels are used for the construction of numerous spent nuclear fuel or radioactive material containers that may be subjected to high strains and moderate strain rates during accidental drop events. Mechanical characteristics of these base materials and their welds under dynamic loads in the strain rate range of concern (1 to 300 per second) are not well documented. However, research is being performed at the Idaho National Laboratory to quantify these characteristics. The work presented herein discusses tensile impact testing of dual-marked 304/304L and 316/316L stainless steel material specimens. Both base material and welded material specimens were tested at -20 oF, room temperature, 300 oF, and 600 oF conditions. Utilizing a drop weight impact test machine and 1/4-inch and 1/2-inch thick dog bone-shaped test specimens, a strain rate range of approximately 4 to 40 per second (depending on initial temperature conditions) was achieved. Factors were determined that reflect the amount of increased strain energy the material can absorb due to strain rate effects. Using the factors, elevated true stress-strain curves for these materials at various strain rates and temperatures were generated. By incorporating the strain rate elevated true stress-strain material curves into an inelastic finite element computer program as the defined material input, significant improvement in the accuracy of the computer analyses was attained. However, additional impact testing is necessary to achieve higher strain rates (up to 300 per second) before complete definition of strain rate effects can be made for accidental drop events and other similar energy-limited impulsive loads. This research approach, using impact testing and a total energy analysis methodology to quantify strain rate effects, can be applied to many other materials used in government and industry.

  20. Apollo command module land impact tests

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  1. Low power arcjet test facility impacts

    NASA Technical Reports Server (NTRS)

    Morren, W. Earl; Lichon, Paul J.

    1992-01-01

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

  2. 49 CFR 325.53 - Site characteristics; stationary test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... in which the motor vehicle is parked at a point that is within 3 feet (.9 m) of the longitudinal position of the vehicle's exhaust system outlet(s). A microphone location point shall be established on the... characteristics; stationary test. (a)(1) The motor vehicle to be tested shall be parked on the test site....

  3. The GISS sounding temperature impact test

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

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

  4. National Job Corps Study: Impacts by Center Characteristics.

    ERIC Educational Resources Information Center

    Burghardt, John; Schochet, Peter Z.

    The question of whether the Job Corps's impacts on students' employment and related outcomes differ according to the characteristics of the Job Corps center attended was examined. The study sample consisted of approximately 9,400 program group members and 6,000 control group members who were randomly selected from among the nearly 81,000…

  5. Testing the Cultural Differences of School Characteristics with Measurement Invariance

    ERIC Educational Resources Information Center

    Demir, Ergül

    2016-01-01

    In this study, it was aimed to model the school characteristics in multivariate structure, and according to this model, aimed to test the invariance of this model across five randomly selected countries and economies from PISA 2012 sample. It is thought that significant differences across group in the context of school characteristics have the…

  6. The Impact of Item Format and Examinee Characteristics on Response Times

    ERIC Educational Resources Information Center

    Hess, Brian J.; Johnston, Mary M.; Lipner, Rebecca S.

    2013-01-01

    Current research on examination response time has focused on tests comprised of traditional multiple-choice items. Consequently, the impact of other innovative or complex item formats on examinee response time is not understood. The present study used multilevel growth modeling to investigate examinee characteristics associated with response time…

  7. Characteristics of dynamic triaxial testing of asphalt mixtures

    NASA Astrophysics Data System (ADS)

    Ulloa Calderon, Alvaro

    Due to the increasing traffic loads and tire pressures, a serious detrimental impact has occurred on flexible pavements in the form of excessive permanent deformation once the critical combination of loading and environmental conditions are reached. This distress, also known as rutting, leads to an increase in road roughness and ultimately jeopardizes the road users' safety. The flow number (FN) simple performance test for asphalt mixtures was one of the final three tests selected for further evaluation from the twenty-four test/material properties initially examined under the NCHRP 9-19 project. Currently, no standard triaxial testing conditions in terms of the magnitude of the deviator and confining stresses have been specified. In addition, a repeated haversine axial compressive load pulse of 0.1 second and a rest period of 0.9 second are commonly used as part of the triaxial testing conditions. The overall objective of this research was to define the loading conditions that created by a moving truck load in the hot mixed asphalt (HMA) layer. The loading conditions were defined in terms of the triaxial stress levels and the corresponding loading time. Dynamic mechanistic analysis with circular stress distribution was used to closely simulate field loading conditions. Extensive mechanistic analyses of three different asphalt pavement structures subjected to moving traffic loads at various speeds and under braking and non-braking conditions were conducted using the 3D-Move model. Prediction equations for estimating the anticipated deviator and confining stresses along with the equivalent deviator stress pulse duration as a function of pavement temperature, vehicle speed, and asphalt mixture's stiffness have been developed. The magnitude of deviator stress, sigmad and confining stress, sigmac, were determined by converting the stress tensor computed in the HMA layer at 2" below pavement surface under a moving 18-wheel truck using the octahedral normal and shear

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

    NASA Technical Reports Server (NTRS)

    Engle, Carl; Herald, Stephen; Watkins, Casey

    2005-01-01

    Contents include the following: Ambient (13A) tests of Cycom 977-2 impact characteristics by the Brucenton and statistical method at MSFC and WSTF. Repeat (13A) tests of tested Cycom from phase I at MSFC to expended testing statistical database. Conduct high-pressure tests (13B) in liquid oxygen (LOX) and GOX at MSFC and WSTF to determine Cycom reaction characteristics and batch effect. Conduct expended ambient (13A) LOX test at MSFC and high-pressure (13B) testing to determine pressure effects in LOX. Expend 13B GOX database.

  9. Impacts of anthropogenic activities on different hydrological drought characteristics

    NASA Astrophysics Data System (ADS)

    Tijdeman, Erik; Stahl, Kerstin; Bachmair, Sophie

    2015-04-01

    The natural hazard drought can have severe impacts on a variety of sectors and at a variety of scales. Droughts, here defined as below average water availability, occur everywhere. However, the impact of a drought event is not only influenced by its severity but also by the vulnerability of an area to droughts. Research in catchments with natural flow conditions is crucial to gain process understanding about hydrological droughts. However, the locations of catchments with natural flow are often not representative for regions with a socioeconomic sector that is highly vulnerable to droughts. In these more vulnerable areas, human activities like groundwater extraction can intensify hydrological droughts. On the other hand, human activities can also mitigate or limit the magnitude of drought events. The aim of this study is to assess the impact of different anthropogenic influences on streamflow droughts by comparing hydrological drought characteristics between catchments with natural streamflow and with regulated or otherwise altered streamflow. The study is based on a large set of streamflow records from catchments in Germany, the UK and the USA with either known anthropogenic influences or natural streamflow conditions. Different drought characteristics (duration, deficit, frequency and timing of drought events) are computed for the selected stations. The drought characteristics in catchments influenced by various anthropogenic activities are stratified by the characteristics of anthropogenic influence, but also by similar physical and climatological properties. These stratified groups are then compared to drought characteristics in natural catchments with similar properties. Results show both negative and positive impacts of different human activities on droughts. For example, urbanized areas with low flow regulations show hydrological droughts with shorter durations and lower deficit volumes compared to nearby natural catchments, while records downstream of

  10. Biopsychosocial characteristics and neurocognitive test performance in National Football League players: an initial assessment.

    PubMed

    Solomon, Gary S; Haase, Richard F

    2008-09-01

    The use of neurocognitive testing in the assessment of professional athletes sustaining sports-related concussions has become widespread over the past decade. Baseline neurocognitive testing is now a requirement for athletes in the National Football League (NFL). We present preliminary normative data on a computer based neurocognitive test (Immediate Post Concussion Assessment and Cognitive Testing; ImPACT) for 159 NFL athletes. Also included are summary data on basic biopsychosocial characteristics, including medical, psychiatric, chemical dependency, concussion, learning disability/attention deficit disorder, and symptom variables, and the relevance of each to baseline neurocognitive test scores.

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

    NASA Technical Reports Server (NTRS)

    Vassilakos, Gregory J.

    2015-01-01

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

  12. Wavelet analysis in ecology and epidemiology: impact of statistical tests

    PubMed Central

    Cazelles, Bernard; Cazelles, Kévin; Chavez, Mario

    2014-01-01

    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

  13. Wavelet analysis in ecology and epidemiology: impact of statistical tests.

    PubMed

    Cazelles, Bernard; Cazelles, Kévin; Chavez, Mario

    2014-02-06

    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.

  14. Accelerated life testing effects on CMOS microcircuit characteristics

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The 250 C, 200C and 125C accelerated tests are described. The wear-out distributions from the 250 and 200 C tests were used to estimate the activation energy between the two test temperatures. The duration of the 125 C test was not sufficient to bring the test devices into the wear-out region. It was estimated that, for the most complex of the three devices types, the activation energy between 200 C and 125 C should be at least as high as that between 250 C and 200 C. The practicality of the use of high temperature for the accelerated life tests from the point of view of durability of equipment is assessed. Guidlines for the development of accelerated life-test conditions are proposed. The use of the silicon nitride overcoat to improve the high temperature accelerated life-test characteristics of CMOS microcircuits is described.

  15. Genetic Testing for Breast Cancer: Psychological and Social Impact

    MedlinePlus

    Genetic testing for breast cancer: Psychological and social impact Genetic testing to estimate breast and ovarian cancer risk ... By Mayo Clinic Staff Thinking about getting a genetic test to find out if you have a ...

  16. Galileo battery testing and the impact of test automation

    NASA Technical Reports Server (NTRS)

    Pertuch, W. T.; Dils, C. T.

    1985-01-01

    Test complexity, changes of test specifications, and the demand for tight control of tests led to the development of automated testing used for Galileo and other projects. The use of standardized interfacing, i.e., IEEE-488, with desktop computers and test instruments, resulted in greater reliability, repeatability, and accuracy of both control and data reporting. Increased flexibility of test programming has reduced costs by permitting a wide spectrum of test requirements at one station rather than many stations.

  17. Instrumented impact testing at high velocities

    SciTech Connect

    Delfosse, D.; Pageau, G.; Bennett, R.; Poursartip, A. Defence Research Establishment Valcartier, Courcelette )

    1993-01-01

    Impact loading of carbon fiber-reinforced plastic (CFRP) aircraft parts is a major concern. Birds or hailstones striking an aircraft generally have a low mass and a high velocity, whereas typically instrumented impact experiments are performed with a high mass and a low velocity. Our aim has been to build an instrumented impact facility with a low-mass projectile capable of simulating these impact events, since there is evidence that a low-velocity impact will not always result in the same amount or even type of damage as a high-velocity impact. This paper provides a detailed description of the instrumented low-mass impact facility at The University of British Columbia (UBC). A gas gun is used to accelerate the instrumented projectile to impact velocities as high as 50 m/s, corresponding to an energy level of 350 J. The contact force during the impact event is measured by an incorporated load cell. The necessary mathematical operations to determine the real load-displacement curves are outlined, and the results of some impact events at different velocities are shown. 23 refs.

  18. Micrometeorite Impact Test of Flex Solar Array Coupon

    NASA Technical Reports Server (NTRS)

    Wright, K. H.; Schneider, T. A.; Vaughn, J. A.; Hoang, B.; Wong, F.; Gardiner, G.

    2016-01-01

    Spacecraft with solar arrays operate throughout the near earth environment and are increasingly planned for outer planet missions. An often overlooked test condition for solar arrays that is applicable to these missions is micrometeorite impacts and possibly electrostatic discharge (ESD) events resulting from these impacts. The Marshall Space Flight Center (MSFC) is partnering with Space Systems/Loral, LLC (SSL) to examine the results of simulated micrometeorite impacts on the electrical performance of an advanced, lightweight flexible solar array design. The test is performed at NASA MSFC's Microlight Gas Gun Facility. The SSL-provided coupons consist of three strings, each string with two solar cells in series. Five impacts will be induced at various locations on a powered test coupon under different string voltage (0 volts - 150 volts) and string current (1.1 amperes - 1.65 amperes) conditions. The maximum specified test voltage and current represent margins of 1.5 times for both voltage and current. The test parameters are chosen to demonstrate new array design robustness to any ESD event caused by plasma plumes resulting from a simulated micrometeorite impact. A second unpowered coupon will undergo two impacts: one impact on the front side and one impact on the back side. Following the impact testing, the second coupon will be exposed to a thermal cycle test to determine possible damage propagation and further electrical degradation due to thermally-induced stress. The setup, checkout, and results from the impact testing are discussed. The challenges for impact testing include precise coupon alignment to control impact location; pressure management during the impact process; and measurement of the true transient electrical response during impact on the powered coupon. Results from pre- and post-test visual and electrical functional testing are also discussed.

  19. Scientists Popularizing Science: Characteristics and Impact of TED Talk Presenters

    PubMed Central

    Sugimoto, Cassidy R.; Thelwall, Mike; Larivière, Vincent; Tsou, Andrew; Mongeon, Philippe; Macaluso, Benoit

    2013-01-01

    The TED (Technology, Entertainment, Design) conference and associated website of recorded conference presentations (TED Talks) is a highly successful disseminator of science-related videos, claiming over a billion online views. Although hundreds of scientists have presented at TED, little information is available regarding the presenters, their academic credentials, and the impact of TED Talks on the general population. This article uses bibliometric and webometric techniques to gather data on the characteristics of TED presenters and videos and analyze the relationship between these characteristics and the subsequent impact of the videos. The results show that the presenters were predominately male and non-academics. Male-authored videos were more popular and more liked when viewed on YouTube. Videos by academic presenters were more commented on than videos by others and were more liked on YouTube, although there was little difference in how frequently they were viewed. The majority of academic presenters were senior faculty, males, from United States-based institutions, were visible online, and were cited more frequently than average for their field. However, giving a TED presentation appeared to have no impact on the number of citations subsequently received by an academic, suggesting that although TED popularizes research, it may not promote the work of scientists within the academic community. PMID:23638069

  20. Psychometric Characteristics of the Gesell School Readiness Screening Test.

    ERIC Educational Resources Information Center

    Lichtenstein, Robert

    The Gesell School Readiness Screening Test (GSRST) is widely used to identify "developmentally immature" children for placement in extra-year, transition programs in spite of a problematic absence of psychometric evidence and research support. In this study of psychometric characteristics of the GSRST, teacher ratings of classroom…

  1. Application of laser, holographic, nondestructive testing by impact loading.

    PubMed

    Wang, J; Grant, I

    1995-07-01

    A description of research on holographic, nondestructive testing (HNDT) with impact loading is presented to demonstrate the technique as a practical HNDT method. The advantages of impact, or impulse, loading coupled with pulsed-laser illumination for HNDT away from the laboratory are discussed. The effect of the loading position, exposure timing, and prestressing on test results is discussed in detail. Experimental verification of the appropriateness of pulsed-laser HNDT in the testing of honeycomb materials by using impact loading is discussed.

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

    NASA Technical Reports Server (NTRS)

    1968-01-01

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

  3. Accelerated life testing effects on CMOS microcircuit characteristics

    NASA Technical Reports Server (NTRS)

    1980-01-01

    This report covers the time period from May 1976 to December 1979 and encompasses the three phases of accelerated testing: Phase 1, the 250 C testing; Phase 2, the 200 C testing; and Phase 3, the 125 C testing. The duration of the test in Phase 1 and Phase 2 was sufficient to take the devices into the wear out region. The wear out distributions were used to estimate the activation energy between the 250 C and the 200 C test temperatures. The duration of the 125 C test, 20,000 hours, was not sufficient to bring the test devices into the wear out region; consequently the third data point at 125 C for determining the consistency of activation energy could not be obtained. It was estimated that, for the most complex of the three device types, the activation energy between 200 C and 125 C should be at least as high as that between 250 C and 200 C. The practicality of the use of high temperature for the accelerated life tests from the point of view of durability of equipment was assessed. Guidelines for the development of accelerated life test conditions were proposed. The use of the silicon nitride overcoat to improve the high temperature accelerated life test characteristics of CMOS microcircuits was explored in Phase 4 of this study and is attached as an appendix to this report.

  4. Advanced Crew Escape Suits (ACES): Particle Impact Test

    NASA Technical Reports Server (NTRS)

    Rosales, Keisa R.; Stoltzfus, Joel M.

    2009-01-01

    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.

  5. Method and apparatus for testing surface characteristics of a material

    NASA Technical Reports Server (NTRS)

    Johnson, David L. (Inventor); Kersker, Karl D. (Inventor); Richardson, David E. (Inventor); Stratton, Troy C. (Inventor)

    2006-01-01

    A method, apparatus and system for testing characteristics of a material sample is provided. The system includes an apparatus configured to house the material test sample while defining a sealed volume against a surface of the material test sample. A source of pressurized fluid is in communication with, and configured to pressurize, the sealed volume. A load applying apparatus is configured to apply a defined load to the material sample while the sealed volume is monitored for leakage of the pressurized fluid. Thus, the inducement of surface defects such as microcracking and crazing may be detected and their effects analyzed for a given material. The material test samples may include laminar structures formed of, for example, carbon cloth phenolic, glass cloth phenolic, silica cloth phenolic materials or carbon-carbon materials. In one embodiment the system may be configured to analyze the material test sample while an across-ply loading is applied thereto.

  6. Orion MPCV Water Landing Test at Hydro Impact Basin

    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...

  7. Negative Impacts of High-Stakes Testing

    ERIC Educational Resources Information Center

    Minarechová, Michaela

    2012-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Komatsu, G. K.

    1978-01-01

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

  9. Vibration characteristics analysis of rotating shrouded blades with impacts

    NASA Astrophysics Data System (ADS)

    Ma, Hui; Xie, Fangtao; Nai, Haiqiang; Wen, Bangchun

    2016-09-01

    A dynamic model of rotating shrouded blades with impacts among adjacent shrouded blades is established considering the effects of the centrifugal stiffening, spin softening and Coriolis force, and the model is validated using finite element method. In the proposed model, the shrouded blade is simplified as a cantilever Euler-Bernoulli beam with a mass point at the free end, and the flexural dynamic stiffness of shrouded blade is selected as contact stiffness during collision. Based on the developed model, the effects of symmetric and asymmetric shroud gaps, rotational speeds, and aerodynamic force amplitudes on the dynamic characteristics of shrouded blades are analyzed through Newmark-β numerical method. The results indicate that (1) the vibro-impact responses of shrouded blades under some asymmetric gaps are more complicated than that under symmetric gap. (2) With the increase of rotational speed from 6000 to 10,000 rev/min, the system vibration experiences from period-three motion, through chaotic motion, finally to period-one motion during collision process because the increasing rotational speed changes the flexural dynamic stiffness of rotating blade. (3) The vibration displacements of shrouded blades increase linearly, and impact force increases linearly with the increase of aerodynamic force amplitude.

  10. 16 CFR 1203.17 - Impact attenuation test.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 1203.17 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.17 Impact attenuation test. (a) Impact test... support assembly) must meet the specifications of Federal Motor Vehicle Safety Standard No....

  11. 16 CFR 1203.17 - Impact attenuation test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 1203.17 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.17 Impact attenuation test. (a) Impact test... support assembly) must meet the specifications of Federal Motor Vehicle Safety Standard No....

  12. 16 CFR 1203.17 - Impact attenuation test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 1203.17 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.17 Impact attenuation test. (a) Impact test... support assembly) must meet the specifications of Federal Motor Vehicle Safety Standard No....

  13. 16 CFR 1203.17 - Impact attenuation test.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 1203.17 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.17 Impact attenuation test. (a) Impact test... support assembly) must meet the specifications of Federal Motor Vehicle Safety Standard No....

  14. 16 CFR 1203.17 - Impact attenuation test.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 1203.17 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.17 Impact attenuation test. (a) Impact test... support assembly) must meet the specifications of Federal Motor Vehicle Safety Standard No....

  15. 16 CFR Figure 9 to Part 1203 - Impact Test Apparatus

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Impact Test Apparatus 9 Figure 9 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS Pt. 1203, Fig. 9 Figure 9 to Part 1203—Impact Test Apparatus...

  16. 16 CFR Figure 9 to Part 1203 - Impact Test Apparatus

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Impact Test Apparatus 9 Figure 9 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS Pt. 1203, Fig. 9 Figure 9 to Part 1203—Impact Test Apparatus...

  17. 16 CFR Figure 9 to Part 1203 - Impact Test Apparatus

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Impact Test Apparatus 9 Figure 9 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS Pt. 1203, Fig. 9 Figure 9 to Part 1203—Impact Test Apparatus...

  18. 16 CFR Figure 9 to Part 1203 - Impact Test Apparatus

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Impact Test Apparatus 9 Figure 9 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS Pt. 1203, Fig. 9 Figure 9 to Part 1203—Impact Test Apparatus...

  19. 16 CFR Figure 9 to Part 1203 - Impact Test Apparatus

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Impact Test Apparatus 9 Figure 9 to Part 1203 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS Pt. 1203, Fig. 9 Figure 9 to Part 1203—Impact Test Apparatus...

  20. 16 CFR 1203.11 - Marking the impact test line.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Marking the impact test line. 1203.11 Section 1203.11 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.11 Marking the impact test line. Prior...

  1. Characteristics of an Optical Delay Line for Radar Testing

    DTIC Science & Technology

    2016-04-12

    Naval Research Laboratory Washington, DC 20375-5320 NRL/MR/5306--16-9654 Characteristics of an Optical Delay Line for Radar Testing April 12, 2016...4555 Overlook Avenue, SW Washington, DC 20375-5320 NRL/MR/5306--16-9654 NAVSEA Approved for public release; distribution is unlimited. Unclassified...2014 – 30 September 2015 4721 2913 Naval Sea Systems Command Washington Navy Yard 1333 Isaac Hull Avenue, SE Washington, DC 20376 0603271N

  2. Fall protection characteristics of safety belts and human impact tolerance.

    PubMed

    Hino, Yasumichi; Ohdo, Katsutoshi; Takahashi, Hiroki

    2014-01-01

    Many fatal accidents due to falls from heights have occurred at construction sites not only in Japan but also in other countries. This study aims to determine the fall prevention performance of two types of safety belts: a body belt, which has been used for more than 40 yr in the Japanese construction industry as a general type of safety equipment for fall accident prevention, and a full harness, which has been used in many other countries. To determine human tolerance for impact trauma, this study discusses features of safety belts with reference to relevant studies in the medical science, automobile crash safety, and aircrew safety. For this purpose, simple drop tests were carried out in a virtual workplace to measure impact load, head acceleration, and posture in the experiments, the Hybrid-III pedestrian model was used as a human dummy. Hybrid-III is typically employed in official automobile crash tests (New Car Assessment Program: NCAP) and is currently recognized as a model that faithfully reproduces dynamic responses. Experimental results shows that safety performance strongly depends on both the variety of safety belts used and the shock absorbers attached onto lanyards. These findings indicate that fall prevention equipment, such as safety belts, lanyards, and shock absorbers, must be improved to reduce impact injuries to the human head and body during falls.

  3. Fall Protection Characteristics of Safety Belts and Human Impact Tolerance.

    PubMed

    Hino, Yasumichi; Ohdo, Katsutoshi; Takahashi, Hiroki

    2014-08-23

    Many fatal accidents due to falls from heights have occurred at construction sites not only in Japan but also in other countries. This study aims to determine the fall prevention performance of two types of safety belts: a body belt(1)), which has been used for more than 40 yr in the Japanese construction industry as a general type of safety equipment for fall accident prevention, and a full harness(2, 3)), which has been used in many other countries. To determine human tolerance for impact trauma, this study discusses features of safety belts with reference(4-9)) to relevant studies in the medical science, automobile crash safety, and aircrew safety. For this purpose, simple drop tests were carried out in a virtual workplace to measure impact load, head acceleration, and posture in the experiments, the Hybrid-III pedestrian model(10)) was used as a human dummy. Hybrid-III is typically employed in official automobile crash tests (New Car Assessment Program: NCAP) and is currently recognized as a model that faithfully reproduces dynamic responses. Experimental results shows that safety performance strongly depends on both the variety of safety belts used and the shock absorbers attached onto lanyards. These findings indicate that fall prevention equipment, such as safety belts, lanyards, and shock absorbers, must be improved to reduce impact injuries to the human head and body during falls.

  4. Preparation of calibrated test packages for particle impact noise detection

    NASA Technical Reports Server (NTRS)

    1977-01-01

    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.

  5. The Impact of EFL Testing on EFL Education in Korea

    ERIC Educational Resources Information Center

    Choi, Inn-Chull

    2008-01-01

    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…

  6. Impact Testing for Materials Science at NASA - MSFC

    NASA Technical Reports Server (NTRS)

    Sikapizye, Mitch

    2010-01-01

    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.

  7. Test-Taker Characteristics and Integrated Speaking Test Performance: A Path-Analytic Study

    ERIC Educational Resources Information Center

    Huang, Heng-Tsung Danny; Hung, Shao-Ting Alan; Hong, He-Ting Vivian

    2016-01-01

    This study explored the relationships among language proficiency, two selected test-taker characteristics (i.e., topical knowledge and anxiety), and integrated speaking test performance. Data collection capitalized on three sets of instruments: three integrated tasks derived from TOEFL-iBT preparation materials, the state anxiety inventory created…

  8. Wind Tunnel Tests on Aerodynamic Characteristics of Advanced Solid Rocket

    NASA Astrophysics Data System (ADS)

    Kitamura, Keiichi; Fujimoto, Keiichiro; Nonaka, Satoshi; Irikado, Tomoko; Fukuzoe, Moriyasu; Shima, Eiji

    The Advanced Solid Rocket is being developed by JAXA (Japan Aerospace Exploration Agency). Since its configuration has been changed very recently, its aerodynamic characteristics are of great interest of the JAXA Advanced Solid Rocket Team. In this study, we carried out wind tunnel tests on the aerodynamic characteristics of the present configuration for Mach 1.5. Six test cases were conducted with different body configurations, attack angles, and roll angles. A six component balance, oilflow visualization, Schlieren images were used throughout the experiments. It was found that, at zero angle-of-attack, the flow around the body were perturbed and its drag (axial force) characteristics were significantly influenced by protruding body components such as flanges, cable ducts, and attitude control units of SMSJ (Solid Motor Side Jet), while the nozzle had a minor role. With angle-of-attack of five degree, normal force of CNα = 3.50±0.03 was measured along with complex flow features observed in the full-component model; whereas no crossflow separations were induced around the no-protuberance model with CNα = 2.58±0.10. These values were almost constant with respect to the angle-of-attack in both of the cases. Furthermore, presence of roll angle made the flow more complicated, involving interactions of separation vortices. These data provide us with fundamental and important aerodynamic insights of the Advanced Solid Rocket, and they will be utilized as reference data for the corresponding numerical analysis.

  9. Micrometeorite Impact Test of Flex Solar Array Coupon

    NASA Technical Reports Server (NTRS)

    Wright, K. H.; Schneider, T. A.; Vaughn, J. A.; Hoang, B.; Wong, F.; Gardiner, G.

    2016-01-01

    Spacecraft with solar arrays operate throughout the near earth environment and are planned for outer planet missions. An often overlooked test condition for solar arrays that is applicable to these missions is micrometeoroid impacts and possibly electrostatic discharge (ESD) events resulting from these impacts. NASA Marshall Space Flight Center (MSFC) is partnering with Space Systems/Loral, LLC (SSL) to examine the results of simulated micrometeoroid impacts on the electrical performance of an advanced, lightweight flexible solar array design. The test is performed at MSFC's Micro Light Gas Gun Facility with SSL-provided coupons. Multiple impacts were induced at various locations on a powered test coupon under different string voltage (0V-150V) and string current (1.1A - 1.65A) conditions. The setup, checkout, and results from the impact testing are discussed.

  10. Impact of uncertainty on modeling and testing

    NASA Technical Reports Server (NTRS)

    Coleman, Hugh W.; Brown, Kendall K.

    1995-01-01

    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.

  11. [Impacts of Ochotona pallasi disturbance on alpine grassland community characteristics].

    PubMed

    Zhao, Guo-qin; Li, Guang-yong; Ma, Wen-hu; Zhao, Dian-zhi; Li, Xiao-yan

    2013-08-01

    Plateau pika is the main fossorial mammal in the alpine grassland in Qinghai Lake Watershed of Northwest China. Based on the field investigation data from 18 alpine grassland quadrats in the Watershed, and by using redundancy analysis (RDA) and the surface fitting offered by 'R-Vegan' , the disturbance intensity of plateau pika (Ochotona pallasi) was classified as four levels. In order to explore the impacts of plateau pika disturbance on the alpine grassland ecosystem and its grazing quality, the community characteristics under different disturbance intensities by plateau pika were analyzed, and a conceptual model about the alpine grassland community succession was proposed. The results showed that with the increase of the disturbance intensity, the dominant species changed from Juncus roemerianus to Poa pratensis and Laux maritima. When the disturbance was small, the community had high quantitative values of coverage, aboveground biomass, biodiversity, and species richness, but the proportion of weeds was also high. When the disturbance was large, the quantitative values were the lowest, while the proportion of weeds was the highest. When the disturbance was moderate, the community had relatively high quantitative values, and the proportion of grasses and sedges was the highest. It was concluded that the community' s characteristic values under low plateau pika disturbance intensity were high but the grazing quality was low, while high disturbance intensity resulted in the grassland degradation. Therefore, the disturbance intensity in the threshold could maintain the stability of alpine grassland ecosystem and improve its grazing quality.

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

    ERIC Educational Resources Information Center

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

    2015-01-01

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

  13. Determining the Overall Impact of Interruptions during Online Testing

    ERIC Educational Resources Information Center

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

    2014-01-01

    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…

  14. An Experimental Study on the Impact Collapse Characteristics of CF/Epoxy Circular Tubes

    NASA Astrophysics Data System (ADS)

    Kim, Y. N.; Im, K. H.; Park, J. W.; Yang, I. Y.

    2003-03-01

    This study is to investigate the energy absorption characteristics of CF/Epoxy (Carbon-Fiber/Epoxy Resin) circular tubes in static and impact tests. The experimental results varied significantly as a function of interlaminar number, orientation angle of outer and trigger. When a CFRP composite tube is crushed, static/impact energy is consumed by friction between the loading plate and the splayed fronds of the tube, by fracture of the fibers, matrix and their interface, and the response is complex and depends on the interaction among the different mechanisms, such as transverse shearing, laminar bending and local buckling. The collapse mode depended upon orientation angle of outer of CFRP tubes and loading status(static/impact). Typical collapse modes of CFRP tubes are wedge collapse mode, splaying collapse mode and fragmentation collapse mode.

  15. Transient analysis of an IVHM grapple impact test

    NASA Technical Reports Server (NTRS)

    Hill, R. G.

    1972-01-01

    A lumped mass model was used to represent the impact condition between a fuel duct and an IVHM in-vessel fuel handling machine. The nonlinear effects of a Bellville spring and the free fall impact of the fuel duct on the IVHM were included. The purpose of the tests was to determine the loads on the fuel duct due to the impact. A comparison between experimental and theoretical results is presented.

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

    SciTech Connect

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

    1995-01-01

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

  17. Shallow seismic test at Marquez impact structure

    NASA Astrophysics Data System (ADS)

    Herrick, R. R.; Sharpton, V. L.

    1997-03-01

    Marquez Dome is the filled and eroded remnant of an about 15-km diameter, 58 Ma impact into unconsolidated sediments in Southeast Texas. The 3-km diameter central peak outcrops as Cretaceous marls and shales at the surface and is flanked by pre- and postimpact tertiary sands and clays. Petroleum exploration data for Marquez include over 160 km of reflection seismic data criss-crossing the site and numerous logged wells. These data have been used to roughly define the extent of the central peak from a zone of no continuous reflectors and the rim from low-angle, modest offset normal faults. A minimum group interval of 33 m and near offset of 100 m cause the industrial seismic data to be of low quality in the upper 250 ms, and consequently these lines do not image the flanks of the central peak and the shallow rim faults. We conducted a shallow seismic investigation to see if engineering seismic equipment could be used to image the flanks of the central peak and fill in the missing 250 ms in the industrial data.

  18. Impact Testing of Orbiter Thermal Protection System Materials

    NASA Technical Reports Server (NTRS)

    Kerr, Justin

    2006-01-01

    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.

  19. Test emission characteristics of motorcycles in Central Taiwan.

    PubMed

    Lin, Chi-Wen; Lu, San-Ju; Lin, Kuo-Shian

    2006-09-15

    Due to the large population and high levels of motorized-vehicle exhaust emissions, motorcycle emissions make an important contribution to total emissions in Taiwan, ROC. Aiming to reduce the air pollution generated by these motorcycles, the Taiwan Environmental Protection Administration (TEPA) has maintained an enforced inspection and maintenance (I/M) program for in-use motorcycles since 1996. This report explores the effects of engine type, engine size, engine age, and manufacturers of in-use motorcycles on CO/HC emissions in I/M testing data during the period of 1996-2002 in the Central Air Quality Basin of Taiwan. Additionally, geographical characteristics and failure rates of motorcycles are analyzed. The results indicate that the age, size, and type of engine, and the manufacturers of motorcycles all play a significant role in determining I/M emission test results. The findings also show that two-stroke motorcycles emitted approximately ten times greater HC than those of four-stroke motorcycles. CO/HC test emissions increase with a decrease in engine size, HC test emissions contributed by Yamaha and other manufacturers being the highest. Although CO/HC test emissions generally increase with the age of the motorcycle, older motorcycles do not contribute significantly to total emissions due to the small number of older motorcycles. It was observed that CO/HC test emissions depend on driving patterns, geographical location, and inspection rates of motorcycles. The failure rate due to CO is nearly four times greater than that of HC, and the older and smaller-engine-size motorcycles obtain greater failure rates. These statistical findings can also provide the EPA of Taiwan or other Asian countries with useful information for formulating better environmental strategies to manage motorcycles effectively.

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

    NASA Technical Reports Server (NTRS)

    Hill, Nicole M.

    2009-01-01

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

  1. Impact on HIV test providers of giving a positive test result.

    PubMed

    Myers, Ted; Worthington, Catherine; Aguinaldo, Jeffrey P; Haubrich, Dennis J; Ryder, Karen; Rawson, Brian

    2007-09-01

    The provision of a positive HIV antibody test result and the direction and support given to the test recipient are critical components of care and prevention. There has been little research that describes what happens in such interactions between recipient and provider. The impact on the test provider of delivering the HIV test result is an important issue to consider. The discomfort experienced by some health providers in giving a positive test result may have adverse effects on the client interaction or may carry over into subsequent client interactions. Utilizing a thematic analysis on interview data from 24 HIV test providers, we describe the impact of delivering a positive test result on HIV test providers, identify the factors that influence this impact, and describe strategies used to manage the impact. As with other health care professionals communicating "bad news,"HIV test providers experience a variety of impacts. While a small number of providers indicated little or no impact of delivering the HIV positive test result because the diagnosis is ''not the end of the world,'' most indicated it was difficult as it was anticipated that the test recipient would (or did) find the news distressing. Several coping strategies were identified.

  2. Material characteristics for an analytic hypervelocity impact performance model

    NASA Astrophysics Data System (ADS)

    Miller, Joshua; Ryan, Shannon

    2015-06-01

    A performance model has recently been developed to describe the evolution of a hypervelocity impact of a threat with a dual-wall, Whipple shield. The Whipple shield uses an initial sacrificial wall to initiate threat fragmentation and melt before the debris expands over a void and is subsequently arrested by the second wall in front of a critical component. As such, understanding the initial interaction of the threat particle and the sacrificial wall is crucial to modeling the overall shield performance. Among the key material parameters that must be defined for the threat particle and sacrificial wall are the equilibrium shock wave states and tensile response to vacuum exposure. This paper documents the work performed to obtain the necessary material characteristics and a description of the fragmentation of the threat needed for the performance model. The results from the use of these quantities within the model are compared here with hydrodynamic simulations and available experimental records that have sought to characterize these parameters.

  3. The impact of Cr adhesion layer on CNFET electrical characteristics

    NASA Astrophysics Data System (ADS)

    Liu, Wei; Chikkadi, Kiran; Muoth, Matthias; Hierold, Christofer; Haluska, Miroslav

    2016-01-01

    The effect of a Cr adhesion layer on the transfer characteristics of Cr/Au-contacted carbon nanotube field-effect transistors (CNFETs) based on individual single-walled carbon nanotubes (SWNTs) is presented in this paper. We show that a very thin Cr layer (≈0.4 nm) already has an impact on the carrier transport in Schottky-barrier-modulated CNFETs. The ratio of the p- and n-branch current is reduced by eight times when the Cr adhesion layer thickness is increased from 0 to 8 nm. We suggest a change in Schottky barrier height at the contact as the determining mechanism for this result. Additionally, superior lifetime of devices is observed even for non-passivated CNFETs with preserved clean SWNT/Cr/Au-contacts using Cr layer thinner than 2 nm. Our experiments show that the role of the adhesion layer in metal/nanotube contacts should be explicitly considered when designing CNTFET-based circuits, developing CNFET fabrication processes, and analyzing the corresponding properties of the electrical contacts.

  4. The impact of Cr adhesion layer on CNFET electrical characteristics.

    PubMed

    Liu, Wei; Chikkadi, Kiran; Muoth, Matthias; Hierold, Christofer; Haluska, Miroslav

    2016-01-08

    The effect of a Cr adhesion layer on the transfer characteristics of Cr/Au-contacted carbon nanotube field-effect transistors (CNFETs) based on individual single-walled carbon nanotubes (SWNTs) is presented in this paper. We show that a very thin Cr layer (≈0.4 nm) already has an impact on the carrier transport in Schottky-barrier-modulated CNFETs. The ratio of the p- and n-branch current is reduced by eight times when the Cr adhesion layer thickness is increased from 0 to 8 nm. We suggest a change in Schottky barrier height at the contact as the determining mechanism for this result. Additionally, superior lifetime of devices is observed even for non-passivated CNFETs with preserved clean SWNT/Cr/Au-contacts using Cr layer thinner than 2 nm. Our experiments show that the role of the adhesion layer in metal/nanotube contacts should be explicitly considered when designing CNTFET-based circuits, developing CNFET fabrication processes, and analyzing the corresponding properties of the electrical contacts.

  5. XDT in HTPB propellant from steel flyer plate impact tests

    NASA Astrophysics Data System (ADS)

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

    2000-04-01

    Several experiments simulating ground impact explosion following the command destruction of a launch vehicle have been performed using HTPB propellant samples of mass 460 to 940 kg impacted by a steel flyer plate. Impact velocities were varied from 135 m/s to 170 m/s. Strong explosions were observed at impact velocities higher than 150 m/s for tests of solid rocket propellant weighting 460 kg. The XDT (Unknown to Detonation Transition) is studied using a bulk failure reaction model including strain rate effect. Computational results are compared with observed blast waves for various impact velocities. The present model has been successfully applied to 22 inch Critical Diameter tests for SRMU HTPB propellant.

  6. Impact Testing and Simulation of Composite Airframe Structures

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  7. Impact performance characteristics and modeling failure mechanisms of pultruded glass-graphite/epoxy hybrid composite beams

    NASA Astrophysics Data System (ADS)

    Kowsika, Murthy V. S. L. N.

    In this study, investigation was performed to comprehend the influence of hybridization on the impact performance in terms of the energy absorption characteristics and delamination fracture toughness of pultruded uni-directional composite materials. In order to evaluate the improvements/changes in the impact performance as a result of hybridization, apart from considering mono-fiber reinforced all-graphite and all-glass composites, several types of sandwich hybrid composites comprising of both graphite as well as glass fibers were included in the investigation. By keeping a constant overall fiber content, the lay-up sequence and the volume fraction of each type of fiber are altered in these pultruded composites to determine the trend in the mechanical behavior as a result of hybridization. The response of pultruded all-graphite, all-glass and glass-graphite hybrid composites is evaluated under two different incident impact energy conditions. A high incident energy (HIE) and a low incident energy (LIE) of impact are chosen to cause either complete fracture or induce delamination, respectively, for assessing the energy absorption characteristics (crashworthiness) and delamination fracture toughness of these composites. Finite element modeling is performed under static as well as dynamic loading conditions to simulate the stress distribution and to predict the energy absorption behavior of composites. Progressive damage due to sequential ply failure was modeled by utilizing the failure strain data obtained from static and HTE impact tests for analyzing the post-initial ply failure characteristics of pultruded composites. Finite element modeling was also performed to simulate delamination crack propagation at various levels through the thickness. The strain energy release rate computed using the virtual crack closure technique was monitored to determine the likelihood of delamination crack propagation with increment in crack growth for the pultruded composites under

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

    NASA Technical Reports Server (NTRS)

    Finchum, Andy; Hubbs, Whitney; Evans, Steve

    2008-01-01

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

  9. Local Population Characteristics and Hemoglobin A1c Testing Rates among Diabetic Medicare Beneficiaries

    PubMed Central

    Yasaitis, Laura C.; Bubolz, Thomas; Skinner, Jonathan S.; Chandra, Amitabh

    2014-01-01

    Background Proposed payment reforms in the US healthcare system would hold providers accountable for the care delivered to an assigned patient population. Annual hemoglobin A1c (HbA1c) tests are recommended for all diabetics, but some patient populations may face barriers to high quality healthcare that are beyond providers' control. The magnitude of fine-grained variations in care for diabetic Medicare beneficiaries, and their associations with local population characteristics, are unknown. Methods HbA1c tests were recorded for 480,745 diabetic Medicare beneficiaries. Spatial analysis was used to create ZIP code-level estimated testing rates. Associations of testing rates with local population characteristics that are outside the control of providers – population density, the percent African American, with less than a high school education, or living in poverty – were assessed. Results In 2009, 83.3% of diabetic Medicare beneficiaries received HbA1c tests. Estimated ZIP code-level rates ranged from 71.0% in the lowest decile to 93.1% in the highest. With each 10% increase in the percent of the population that was African American, associated HbA1c testing rates were 0.24% lower (95% CI −0.32–−0.17); for identical increases in the percent with less than a high school education or the percent living in poverty, testing rates were 0.70% lower (−0.95–−0.46) and 1.6% lower (−1.8–−1.4), respectively. Testing rates were lowest in the least and most densely populated ZIP codes. Population characteristics explained 5% of testing rate variations. Conclusions HbA1c testing rates are associated with population characteristics, but these characteristics fail to explain the vast majority of variations. Consequently, even complete risk-adjustment may have little impact on some process of care quality measures; much of the ZIP code-related variations in testing rates likely result from provider-based differences and idiosyncratic local factors not related to

  10. Quality assurance of absorbed energy in Charpy impact test

    NASA Astrophysics Data System (ADS)

    Rocha, C. L. F.; Fabricio, D. A. K.; Costa, V. M.; Reguly, A.

    2016-07-01

    In order to ensure the quality assurance and comply with standard requirements, an intralaboratory study has been performed for impact Charpy tests, involving two operators. The results based on ANOVA (Analysis of Variance) and Normalized Error statistical techniques pointed out that the execution of the tests is appropriate, because the implementation of quality assurance methods showed acceptable results.

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

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  12. Assessment of asphalt mixtures characteristics through GPR testing

    NASA Astrophysics Data System (ADS)

    Pais, Jorge; Fernandes, Francisco

    2014-05-01

    Road pavements are composed by granular and asphalt layers, placed over the pavement subgrade, which are designed to resist to traffic and climatic effects. Pavement distresses include permanent deformation mainly due to the contribution of the subgrade and fatigue cracking in the asphalt layers. Fatigue cracking is the main pavement distress and is responsible for the main rehabilitations carried out in road pavements which leads, in most cases, to the pavement reconstruction due to the severity of the cracking observed in many roads. For a given aggregate gradation, the fatigue cracking resistance is related to the proportions of the components in the asphalt mixtures, namely the void content and the binder content. Also the presence of water, or moisture, has an important influence in the fatigue resistance, and its effect is characterized by a reduction in the fatigue cracking resistance. The characteristics of the asphalt mixtures applied in road pavements can be assessed in laboratory through the testing of cores extracted from the pavement. These cores are extracted some representative section of the pavement, usually equally spaced in the road. Due to the construction process, the representative sections of the pavement don't allow to identify the quality of the whole pavement. Thus, the use of continuous measurement is essential to ensure the perfect assessment of the pavement quality and the use of the GPR assumes a paramount importance. Thus, this communication presents several GPR tests carried out on pavement slabs produced in laboratory with different void content, binder content and moisture content in order to establish different classifiers that will allow the identification of this condition during regular inspections. Furthermore, tests carried on specimens before and after fatigue tests will allow to calculate similar parameters to estimate the state of conservation of pavements in terms of stiffness and the presence of cracks. This work is a

  13. Preferred HIV testing services and programme characteristics among clients of a rapid HIV testing programme

    PubMed Central

    2013-01-01

    Background In the current context of diversity and coexistence of HIV testing approaches, limited information exists on test recipient’s views of HIV testing services and programme attributes that could ease the testing process and make it more appealing for at risk individuals who don’t know their HIV status. This study analyzed ratings given to different testing sites and programme characteristics that might facilitate testing. Methods We analyzed data from 3120 persons attending a mobile HIV testing programme located on a central street in the gay district of Madrid. Results 64% were men (of which, 55% had had sex with other men), 59.5% were <30 years, 35.4% foreigners, 50.6% had a university degree,71.7% a regular employment, 59.3% reported multiple partners and inconsistent condom use and 56.5% had been tested for HIV. Non Governmental Organizations and specific HIV/STI centres received the maximum rating from over 60% of participants, followed by self-testing (38.9%). Pharmacies (20.8%) and hospital emergency departments (14.2%) were the worst valued testing sites. Over 80% gave the highest rating to having immediate test results, not needing a previous appointment, and free testing, while less than 50% gave the maximum rating to privacy and anonymity. Conclusions HIV testing services that don’t require an appointment, based on free tests with rapid results are most valued by a young, not socially marginalized but high risk sexual exposure population. On the contrary, issues traditionally highly valued by health care providers or AIDS social organizations (privacy and anonymity) are much less valued. PMID:23987230

  14. 76 FR 31860 - Anthropomorphic Test Devices; Hybrid III Test Dummy, ES-2re Side Impact Crash Test Dummy

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-02

    ... National Highway Traffic Safety Administration 49 CFR Part 572 RIN 2127-AK64 Anthropomorphic Test Devices; Hybrid III Test Dummy, ES-2re Side Impact Crash Test Dummy AGENCY: National Highway Traffic Safety... rule published on June 16, 2008, concerning a 50th percentile adult male side crash test dummy...

  15. 75 FR 5931 - Anthropomorphic Test Devices; Hybrid III Test Dummy, ES-2re Side Impact Crash Test Dummy

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-05

    ... National Highway Traffic Safety Administration 49 CFR Part 572 RIN 2127-AK64 Anthropomorphic Test Devices; Hybrid III Test Dummy, ES-2re Side Impact Crash Test Dummy AGENCY: National Highway Traffic Safety... final rule that had adopted specifications and qualification requirements for a new crash test...

  16. Test bed experiments for various telerobotic system characteristics and configurations

    NASA Technical Reports Server (NTRS)

    Duffie, Neil A.; Wiker, Steven F.; Zik, John J.

    1990-01-01

    Dexterous manipulation and grasping in telerobotic systems depends on the integration of high-performance sensors, displays, actuators and controls into systems in which careful consideration has been given to human perception and tolerance. Research underway at the Wisconsin Center for Space Automation and Robotics (WCSAR) has the objective of enhancing the performance of these systems and their components, and quantifying the effects of the many electrical, mechanical, control, and human factors that affect their performance. This will lead to a fundamental understanding of performance issues which will in turn allow designers to evaluate sensor, actuator, display, and control technologies with respect to generic measures of dexterous performance. As part of this effort, an experimental test bed was developed which has telerobotic components with exceptionally high fidelity in master/slave operation. A Telerobotic Performance Analysis System has also been developed which allows performance to be determined for various system configurations and electro-mechanical characteristics. Both this performance analysis system and test bed experiments are described.

  17. Impact of Measurement System Characteristics on Advanced Sounder Information Content

    NASA Technical Reports Server (NTRS)

    Larar, Allen M.; Liu, Xu; Zhou, Daniel K.

    2011-01-01

    Advanced satellite sensors are tasked with improving global observations of the Earth's atmosphere, clouds, and surface to enable enhancements in weather prediction, climate monitoring capability, and environmental change detection. Achieving such an improvement in geophysical information inferred from these observations requires optimal usage of data from current systems as well as instrument system enhancements for future sensors. This presentation addresses results of tradeoff studies evaluating the impact of spectral resolution, spectral coverage, instrument noise, and a priori knowledge on remote sensing system information content, with a specific emphasis on thermodynamic state and trace species information obtainable from advanced atmospheric sounders. Particular attention will be devoted toward information achievable from the Atmospheric InfraRed Sounder (AIRS) on the NASA EOS Aqua satellite in orbit since 2002, the Infrared Atmospheric Sounding Interferometer (IASI) aboard MetOp-A since 2006, and the Cross-track Infrared Sounder (CrIS) instrument to fly aboard the NPP and JPSS series of satellites expected to begin in late 2011. While all of these systems cover nearly the same infrared spectral extent, they have very different number of channels, instrument line shapes, coverage continuity, and instrument noise. AIRS is a grating spectrometer having 2378 discrete spectral channels ranging from about 0.4 to 2.2/cm resolution; IASI is a Michelson interferometer with 8461 uniformly-spaced spectral channels of 0.5/cm (apodized) resolution; and CrIS is a Michelson interferometer having 1305 spectral channels of 0.625, 1.250, and 2.50/cm (unapodized) spectral resolution, respectively, over its three continuous but non-overlapping bands. Results of tradeoff studies showing information content sensitivity to assumed measurement system characteristics will be presented.

  18. Impact Testing of Composites for Aircraft Engine Fan Cases

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    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.

  19. The impact of network characteristics on the diffusion of innovations

    NASA Astrophysics Data System (ADS)

    Peres, Renana

    2014-05-01

    This paper studies the influence of network topology on the speed and reach of new product diffusion. While previous research has focused on comparing network types, this paper explores explicitly the relationship between topology and measurements of diffusion effectiveness. We study simultaneously the effect of three network metrics: the average degree, the relative degree of social hubs (i.e., the ratio of the average degree of highly-connected individuals to the average degree of the entire population), and the clustering coefficient. A novel network-generation procedure based on random graphs with a planted partition is used to generate 160 networks with a wide range of values for these topological metrics. Using an agent-based model, we simulate diffusion on these networks and check the dependence of the net present value (NPV) of the number of adopters over time on the network metrics. We find that the average degree and the relative degree of social hubs have a positive influence on diffusion. This result emphasizes the importance of high network connectivity and strong hubs. The clustering coefficient has a negative impact on diffusion, a finding that contributes to the ongoing controversy on the benefits and disadvantages of transitivity. These results hold for both monopolistic and duopolistic markets, and were also tested on a sample of 12 real networks.

  20. The Impact of Personality and Test Conditions on Mathematical Test Performance

    ERIC Educational Resources Information Center

    Hayes, Heather; Embretson, Susan E.

    2013-01-01

    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…

  1. Microstructural characterization of Charpy-impact-tested nanostructured bainite

    SciTech Connect

    Tsai, Y.T.; Chang, H.T.; Huang, B.M.; Huang, C.Y.; Yang, J.R.

    2015-09-15

    In this work, a possible cause of the extraordinary low impact toughness of nanostructured bainite has been investigated. The microstructure of nanostructured bainite consisted chiefly of carbide-free bainitic ferrite with retained austenite films. X-ray diffractometry (XRD) measurement indicated that no retained austenite existed in the fractured surface of the Charpy-impact-tested specimens. Fractographs showed that cracks propagated mainly along bainitic ferrite platelet boundaries. The change in microstructure after impact loading was verified by transmission electron microscopy (TEM) observations, confirming that retained austenite was completely transformed to strain-induced martensite during the Charpy impact test. However, the zone affected by strained-induced martensite was found to be extremely shallow, only to a depth of several micrometers from the fracture surface. It is appropriately concluded that upon impact, as the crack forms and propagates, strain-induced martensitic transformation immediately occurs ahead of the advancing crack tip. The successive martensitic transformation profoundly facilitates the crack propagation, resulting in the extremely low impact toughness of nanostructured bainite. Retained austenite, in contrast to its well-known beneficial role, has a deteriorating effect on toughness during the course of Charpy impact. - Highlights: • The microstructure of nanostructured bainite consisted of nano-sized bainitic ferrite subunits with retained austenite films. • Special sample preparations for SEM, XRD and TEM were made, and the strain-affected structures have been explored. • Retained austenite films were found to transform into martensite after impact loading, as evidenced by XRD and TEM results. • The zone of strain-induced martensite was found to extend to only several micrometers from the fracture surface. • The poor Charpy impact toughness is associated with the fracture of martensite at a high strain rate during

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

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Evans, Steve; Finchum, Andy; Hubbs, Whitney

    2008-01-01

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

  4. Methods for testing theory and evaluating impact in randomized field trials

    PubMed Central

    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

    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

  5. Methodology for mapping football head impact exposure to helmet pads for repeated loading testing.

    PubMed

    MacAlister, Anna; Young, Tyler; Daniel, Ray W; Rowson, Steven; Duma, Stefan M

    2014-01-01

    Football helmets have a lifespan of 10 years; however, no work has investigated how helmet padding properties change over time with use. The purpose of this study is to develop a methodology to control repeated pad loading and quantify changes in energy management. Head impact exposure data for 7-8 year old football players were used to find an average impact magnitude. NOCSAE-style drop tests were performed using an instrumented headform fitted with the same style helmet (Helmet A) used to collect population data to determine the compression depth and rate of the helmet padding during an average impact. Drops from the same height were then conducted for two other helmet types (Helmet B and Helmet C). For the average impact of ~15 g, the compression depth and rate of the pads from Helmet A were found to be 9.8 mm and 0.72 m/s respectively. The compression depths and rates for Helmets B and C were found to be 6.1 mm and 0.71 m/s and 10.7 mm and 0.69 m/s respectively. These parameters were utilized by a material testing system program to impact helmet padding. Repeated helmet pad loading can be tested using a material testing system for populations with known head impact exposure. The energy absorbing characteristics of the padding can be used to develop new safety regulations regarding the lifetime of helmets, affording better protection to athletes.

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

    NASA Technical Reports Server (NTRS)

    Scaglione, Lois J.

    1995-01-01

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

  7. Impact tests on rubber compression springs for airplane landing gears

    NASA Technical Reports Server (NTRS)

    Hohenemser, K

    1930-01-01

    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.

  8. Hypervelocity Impact Testing of Nickel Hydrogen Battery Cells

    NASA Technical Reports Server (NTRS)

    Frate, David T.; Nahra, Henry K.

    1996-01-01

    Nickel-Hydrogen (Ni/H2) battery cells have been used on several satellites and are planned for use on the International Space Station. In January 1992, the NASA Lewis Research Center (LeRC) conducted hypervelocity impact testing on Ni/H2 cells to characterize their failure modes. The cell's outer construction was a 24 mil-thick Inconel 718 pressure vessel. A sheet of 1.27 cm thick honeycomb was placed in front of the battery cells during testing to simulate the on-orbit box enclosure. Testing was conducted at the NASA White Sands Test Facility (WSTF). The hypervelocity gun used was a 7.6 mm (0.30 caliber) two-stage light gas gun. Test were performed at speeds of 3, 6, and 7 km/sec using aluminum 2017 spherical particles of either 4.8 or 6.4 mm diameter as the projectile. The battery cells were electrically charged to about 75 percent of capacity, then back-filled with hydrogen gas to 900 psi simulating the full charge condition. High speed film at 10,000 frames/sec was taken of the impacts. Impacts in the dome area (top) and the electrode area (middle) of the battery cells were investigated. Five tests on battery cells were performed. The results revealed that in all of the test conditions investigated, the battery cells simply vented their hydrogen gas and some electrolyte, but did not burst or generate any large debris fragments.

  9. Hypervelocity Impact Test Results for a Metallic Thermal Protection System

    NASA Technical Reports Server (NTRS)

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

    2003-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.

    2010-01-01

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

  11. End-on radioisotope thermoelectric generator impact tests

    SciTech Connect

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

    1997-01-01

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

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

    SciTech Connect

    Salama, M.; Davis, G.; Kuo, C.P.

    1994-12-31

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

  13. 16 CFR 1203.11 - Marking the impact test line.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Marking the impact test line. 1203.11 Section 1203.11 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT... the helmet on the appropriate headform as specified by the manufacturer's helmet positioning...

  14. Hypervelocity impact tests on Space Shuttle Orbiter thermal protection material

    NASA Technical Reports Server (NTRS)

    Humes, D. H.

    1977-01-01

    Hypervelocity impact tests were conducted to simulate the damage that meteoroids will produce in the Shuttle Orbiter leading edge structural subsystem material. The nature and extent of the damage is reported and the probability of encountering meteoroids with sufficient energy to produce such damage is discussed.

  15. Performance verification of impact machines for testing plastics

    SciTech Connect

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

    1999-12-01

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

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

    SciTech Connect

    Brennan, R. E.; Green, W. H.

    2011-06-23

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

  17. Sloshing roof impact tests of a rectangular tank

    SciTech Connect

    Minowa, C.; Ogawa, N.; Harada, I.; Ma, D.C.

    1994-06-01

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

  18. Sloshing roof impact tests of a rectangular tank

    NASA Astrophysics Data System (ADS)

    Minowa, Chikahiro; Ogawa, Nobuyuki; Harada, Iki; Ma, David C.

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

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

    SciTech Connect

    Whittington, K.F.; Lutz, C.E.

    1995-12-31

    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.

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

    SciTech Connect

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

    2007-07-01

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

  1. Experimental sloshing pressure impacts in ensemble domain: Transient and stationary statistical characteristics

    SciTech Connect

    Bulian, G.; Botia-Vera, E. E-mail: antonio.souto@upm.es; Souto-Iglesias, A. E-mail: antonio.souto@upm.es

    2014-03-15

    The present paper focuses on the analysis of impact pressure registrations from repeated model scale sloshing experiments under harmonic rotational excitation. A series of more than 100 experiments, each one encompassing more than 100 impact events, has been conducted seeking the highest feasible repeatability. Different excitation periods, that cover the main features of the impact dynamics, have been considered in a preliminary screening, describing the main features of the impact dynamics. Since, even under a nominally deterministic excitation, the pressure at each impact is characterized by a high variability, a statistical approach is used treating the impact pressure as a stochastic process. For one selected excitation period, the statistical analysis focuses on the ensemble distribution of the maximum pressure during each impact event. Particular attention is given to the evolution of such distributions, in order to detect the variations in the statistical characteristics of the process. This is achieved by, first, identifying the presence and the length of the transient phase and, second, by characterizing the process at stationary state. The statistics of impact pressure for different peaks are discussed mostly in the ensemble domain. Linking the latter with the time domain analysis is made by checking that the problem can be considered “practically ergodic.” The “practical ergodicity” of the process is dealt with by checking to what extent steady state ensemble statistical information can be obtained from a single long run experiment. Statistical checks for correlation and independence of maximum impact pressures are also carried out to test the hypothesis of independent identically distributed random variables. The method of analysis presented in this paper through the considered example case is general in nature and is considered to be highly portable. In particular, it is considered to allow for a more thorough understanding of non

  2. A drop tower for controlled impact testing of biological tissues.

    PubMed

    Burgin, Leanne V; Aspden, Richard M

    2007-05-01

    Impact damage, in particular to tissues such as articular cartilage, is a recognised source of morbidity. To understand better the clinical outcomes, it is important to know the mechanics of the damage sustained and the biological response of cells to rapidly applied forces and subsequent tissue disruption. An instrumented drop tower has been designed to enable controlled impact loads to be applied to small samples of biological materials. Impact severity can be controlled by using impactors of different masses and various drop heights. Force and deceleration at impact are recorded at 50,000 samples s(-1) by a force transducer under the sample and an accelerometer on the impactor. Repeatability was tested on rubber washers and coefficients of variation were found to be better than 8% for dynamic stiffness, 3.4% for stress and 4.3% for strain. Initial tests on isolated biopsies of articular cartilage showed that at an initial strain rate of 916 s(-1), the peak dynamic modulus of human femoral head cartilage was 59 MPa, and for a bovine biopsy the initial strain rate and corresponding peak dynamic modulus were 3380 s(-1) and 130 MPa, respectively. The equipment described is capable of applying an impact load to small biopsies of tissue with a defined energy and velocity and measuring deformation and load at high rates of loading.

  3. Hydrodynamic impact analysis and testing of an unmanned aerial vehicle

    NASA Astrophysics Data System (ADS)

    Bird, Isabel

    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.

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

    NASA Technical Reports Server (NTRS)

    Gradl, Paul R.; Stephens, Walter

    2005-01-01

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

  5. Hypervelocity Impact Test Facility: A gun for hire

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  6. Hypervelocity Impact Test Facility: A gun for hire

    NASA Astrophysics Data System (ADS)

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

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

  7. Effect of matrix resin on the impact fracture characteristics of graphite-epoxy laminates

    NASA Technical Reports Server (NTRS)

    Hertzberg, P. E.; Smith, B. W.; Miller, A. G.

    1982-01-01

    The effect of resin chemistry on basic impact energy absorbent mechanisms exibited by graphite-epoxy composites was investigated. Impact fracture modes and microscopic resin deformation characteristics were examined for 26 NASA-impacted graphite epoxy laminates with different resin chemistries. Discrete specimen fracture modes were identified through cross sectional examination after impact, and subsequently compared with measured glass transition temperatures, cure cycles, and residual impact capabilities. Microscopic resin deformation mechanisms and their overall relationship to impact loading conditions, voids, and resin content were also characterized through scanning electron microscopic examination of separated fracture surfaces.

  8. Flash characteristics of plasma induced by hypervelocity impact

    NASA Astrophysics Data System (ADS)

    Zhang, Kai; Long, Renrong; Zhang, Qingming; Xue, Yijiang; Ju, Yuanyuan

    2016-08-01

    Using a two-stage light gas gun, a series of hypervelocity impact experiments was conducted in which 6.4-mm-diameter spherical 2024-aluminum projectiles impact 23-mm-thick targets made of the same material at velocities of 5.0, 5.6, and 6.3 km/s. Both an optical pyrometer composed of six photomultiplier tubes and a spectrograph were used to measure the flash of the plasma during hypervelocity impact. Experimental results show that, at a projectile velocity of 6.3 km/s, the strong flash lasted about 10 μs and reached a temperature of 4300 K. Based on the known emission lines of AL I, spectral methods can provide the plasma electron temperature. An electron-temperature comparison between experiment and theoretical calculation indicates that single ionization and secondary ionization are the two main ionizing modes at velocities 5.0-6.3 km/s.

  9. Product Reputation Manipulation: The Characteristics and Impact of Shill Reviews

    ERIC Educational Resources Information Center

    Ong, Toan C.

    2013-01-01

    Online reviews have become a popular method for consumers to express personal evaluation about products. Ecommerce firms have invested heavily into review systems because of the impact of product reviews on product sales and shopping behavior. However, the usage of product reviews is undermined by the increasing appearance of shill or fake…

  10. Test plan. Task 5, subtask 5.2: Early on-orbit TPSdebris impact tests

    NASA Technical Reports Server (NTRS)

    Greenberg, H. S.

    1994-01-01

    The limitation of damage to, and survival of, the cryogenic tankage during the on-orbit stay despite potential impact of orbital debris, may be a significant discriminator in the RHCTS trade studies described in the TA-1 trade study plan (ref. RHCTS-TSP-1) dated July 29, 1994. The objective of this early phase of an overall debris impact test program is to provide the data to support assessment of the relative suitability of integral and non integral tanks.

  11. Accelerated life testing effects on CMOS microcircuit characteristics

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Accelerated life tests were performed on CMOS microcircuits to predict their long term reliability. The consistency of the CMOS microcircuit activation energy between the range of 125 C to 200 C and the range 200 C to 250 C was determined. Results indicate CMOS complexity and the amount of moisture detected inside the devices after testing influences time to failure of tested CMOS devices.

  12. Radioisotope thermoelectric generator/thin fragment impact test

    SciTech Connect

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

    1998-12-31

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

  13. Simulated hail impact testing of photovoltaic solar panels

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

    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.

  14. Charpy impact test results for low-activation ferritic alloys

    SciTech Connect

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

    1987-05-01

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

  15. Shock Testing the SEAWOLF Submarine, Final Environmental Impact Statement

    DTIC Science & Technology

    1998-05-01

    that would settle to the seafloor would be the top plate and crossbar, which together weigh 204 kg (450 lb). After detonation, the test array would be...but would have no significant impact on bottom structure or form. The largest possible fragment from the explosion is the top plate and crossbar...is the top plate and crossbar, which together weigh 204 kg (450 lb). Due to low oxygen levels in bottom sediments, the steel fragments would likely

  16. Discovering the Impact of Preceding Units' Characteristics on the Wait Time of Cardiac Surgery Unit from Statistic Data

    PubMed Central

    Liu, Jiming; Tao, Li; Xiao, Bo

    2011-01-01

    Introduction Prior research shows that clinical demand and supplier capacity significantly affect the throughput and the wait time within an isolated unit. However, it is doubtful whether characteristics (i.e., demand, capacity, throughput, and wait time) of one unit would affect the wait time of subsequent units on the patient flow process. Focusing on cardiac care, this paper aims to examine the impact of characteristics of the catheterization unit (CU) on the wait time of cardiac surgery unit (SU). Methods This study integrates published data from several sources on characteristics of the CU and SU units in 11 hospitals in Ontario, Canada between 2005 and 2008. It proposes a two-layer wait time model (with each layer representing one unit) to examine the impact of CU's characteristics on the wait time of SU and test the hypotheses using the Partial Least Squares-based Structural Equation Modeling analysis tool. Results Results show that: (i) wait time of CU has a direct positive impact on wait time of SU (); (ii) capacity of CU has a direct positive impact on demand of SU (); (iii) within each unit, there exist significant relationships among different characteristics (except for the effect of throughput on wait time in SU). Conclusion Characteristics of CU have direct and indirect impacts on wait time of SU. Specifically, demand and wait time of preceding unit are good predictors for wait time of subsequent units. This suggests that considering such cross-unit effects is necessary when alleviating wait time in a health care system. Further, different patient risk profiles may affect wait time in different ways (e.g., positive or negative effects) within SU. This implies that the wait time management should carefully consider the relationship between priority triage and risk stratification, especially for cardiac surgery. PMID:21818282

  17. Data Reduction and Its Impact on Test-Analysis Correlation

    NASA Technical Reports Server (NTRS)

    Lyle, Karen H.; Bark, Lindley W.

    2001-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

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

    SciTech Connect

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

    1995-09-01

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

  20. Estimating Testing Time: The Effects of Item Characteristics on Response Latency.

    ERIC Educational Resources Information Center

    Halkitis, Perry N.; And Others

    The relationship between test item characteristics and testing time was studied for a computer-administered licensing examination. One objective of the study was to develop a model to predict testing time on the basis of known item characteristics. Response latencies (i.e., the amount of time taken by examinees to read, review, and answer items)…

  1. Ecological impacts of invasive alien species along temperature gradients: testing the role of environmental matching.

    PubMed

    Iacarella, Josephine C; Dick, Jaimie T A; Alexander, Mhairi E; Ricciardi, Anthony

    2015-04-01

    Invasive alien species (IAS) can cause substantive ecological impacts, and the role of temperature in mediating these impacts may become increasingly significant in a changing climate. Habitat conditions and physiological optima offer predictive information for IAS impacts in novel environments. Here, using meta-analysis and laboratory experiments, we tested the hypothesis that the impacts of IAS in the field are inversely correlated with the difference in their ambient and optimal temperatures. A meta-analysis of 29 studies of consumptive impacts of IAS in inland waters revealed that the impacts of fishes and crustaceans are higher at temperatures that more closely match their thermal growth optima. In particular, the maximum impact potential was constrained by increased differences between ambient and optimal temperatures, as indicated by the steeper slope of a quantile regression on the upper 25th percentile of impact data compared to that of a weighted linear regression on all data with measured variances. We complemented this study with an experimental analysis of the functional response (the relationship between predation rate and prey supply) of two invasive predators (freshwater mysid shrimp, Hemimysis anomala and Mysis diluviana) across. relevant temperature gradients; both of these species have previously been found to exert strong community-level impacts that are corroborated by their functional responses to different prey items. The functional response experiments showed that maximum feeding rates of H. anomala and M. diluviana have distinct peaks near their respective thermal optima. Although variation in impacts may be caused by numerous abiotic or biotic habitat characteristics, both our analyses point to temperature as a key mediator of IAS impact levels in inland waters and suggest that IAS management should prioritize habitats in the invaded range that more closely match the thermal optima of targeted invaders.

  2. Impact of cranberry on Escherichia coli cellular surface characteristics

    SciTech Connect

    Johnson, Brandy J.; Malanoski, Anthony P.; Ligler, Frances S.

    2008-12-19

    The anti-adhesive effects of cranberry have been attributed to both interactions of its components with the surface of bacterial cells and to inhibition of p-fimbriae expression. Previous reports also suggested that the presence of cranberry juice changed the Gram stain characteristics of Escherichia coli. Here, we show that the morphology of E. coli is changed when grown in the presence of juice or extract from Vaccinium macrocarpon (cranberry). Gene expression analysis indicates the down regulation of flagellar basal body rod and motor proteins. Consistent with this finding and previous reports, the SEM images indicate a decrease in the visible p-fimbriae. The iodine used in Gram-staining protocols was found to interact differently with the bacterial membrane when cells were cultured in spiked media. Slight alterations in the Gram stain protocol demonstrated that culturing in the presence of cranberry juice does not change the Gram stain characteristics contradicting other reports.

  3. Cometary Dust Characteristics: Comparison of Stardust Craters with Laboratory Impacts

    NASA Technical Reports Server (NTRS)

    Kearsley, A. T.; Burchell, M. J.; Graham, G. A.; Horz, F.; Wozniakiewicz, P. A.; Cole, M. J.

    2007-01-01

    Aluminium foils exposed to impact during the passage of the Stardust spacecraft through the coma of comet Wild 2 have preserved a record of a wide range of dust particle sizes. The encounter velocity and dust incidence direction are well constrained and can be simulated by laboratory shots. A crater size calibration programme based upon buckshot firings of tightly constrained sizes (monodispersive) of glass, polymer and metal beads has yielded a suite of scaling factors for interpretation of the original impacting grain dimensions. We have now extended our study to include recognition of particle density for better matching of crater to impactor diameter. A novel application of stereometric crater shape measurement, using paired scanning electron microscope (SEM) images has shown that impactors of differing density yield different crater depth/diameter ratios. Comparison of the three-dimensional gross morphology of our experimental craters with those from Stardust reveals that most of the larger Stardust impacts were produced by grains of low internal porosity.

  4. The influence of seatback characteristics on cervical injury risk in severe rear impacts.

    PubMed

    Burnett, Roger; Carter, Jarrod; Roberts, Verne; Myers, Barry

    2004-07-01

    The determination of the optimum seatback characteristics for the mitigation of serious and catastrophic neck injury during high-speed rear-end collisions remains a topic of continued investigation. Despite a number of prior research efforts, both field data and sled test studies have yet to define a single optimal seatback performance criterion. Further, recent developments in seatbacks have introduced new designs into the field that have not been compared to more traditional designs. Analysis of NASS data from 1980 to 1999 demonstrated that at changes in velocity (DeltaV) above 40 kph, rear-end collisions have a dramatically lower risk for catastrophic injury than frontal, near-side or far-side impacts. Unfortunately, owing to the small penetration of newer seatback designs in the automotive fleet, it is not possible to examine the influence of seatback design parameters on serious neck injury using these data alone. Accordingly, seven rear impact HYGE sled tests were conducted using a wide range of seat designs. Upper and lower neck load cells were used to measure neck forces and moments in restrained 50th male Hybrid III anthropomorphic test devices (ATD). Additionally, the neck injury criteria (Nij) was computed. Unlike prior studies that have examined the standard seated ATD or the dramatically out-of-position ATD, these tests were conducted using an ATD seated in non-standard but typical driving position. The results of this study indicate that several descriptions of seatback behavior, such as quasi-static ultimate force are poor predictors of ATD neck loading. It also suggests that, for the severe crash studied, an optimum range of seatback stiffness exists, which appears to be in the mid-range of seatback stiffnesses available in current production vehicles. These data continue to illustrate the complex relationship of seatback design parameters to neck injury risk.

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

    NASA Technical Reports Server (NTRS)

    Vassilakos, Gregory J.; Hardy, Robin C.

    2012-01-01

    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.

  6. Accelerated life testing effects on CMOS microcircuit characteristics, phase 1

    NASA Technical Reports Server (NTRS)

    Maximow, B.

    1976-01-01

    An accelerated life test of sufficient duration to generate a minimum of 50% cumulative failures in lots of CMOS devices was conducted to provide a basis for determining the consistency of activation energy at 250 C. An investigation was made to determine whether any thresholds were exceeded during the high temperature testing, which could trigger failure mechanisms unique to that temperature. The usefulness of the 250 C temperature test as a predictor of long term reliability was evaluated.

  7. How Changes in Psychosocial Job Characteristics Impact Burnout in Nurses: A Longitudinal Analysis

    PubMed Central

    Pisanti, Renato; van der Doef, Margot; Maes, Stan; Meier, Laurenz Linus; Lazzari, David; Violani, Cristiano

    2016-01-01

    Aims: The main aim of this longitudinal study was to test the Job Demand-Control-Support (JDCS) model and to analyze whether changes in psychosocial job characteristics are related to (changes in) burnout. Background: Previous studies on the effects of JDCS variables on burnout dimensions have indicated that the iso-strain hypothesis (i.e., high job demands, low control, and low support additively predict high stress reactions) and the buffer hypotheses (i.e., high job control and/or social support is expected to moderate the negative impact of high demands on stress reactions) have hardly been examined concurrently in a longitudinal design; and that the effects of changes of psychosocial job variables on burnout dimensions have hardly been analyzed. Design: This two wave study was carried out over a period of 14 months in a sample of 217 Italian nurses. Method: Hierarchical regression analyses were used to test the cross lagged main and interactive effects of JDCS variables, and to analyse the across-time effects of changes in JDCS dimensions on burnout variables. Results: The Time 1 job characteristics explained 2–8% of the variance in the Time 2 burnout dimensions, but no support for the additive, or the buffer hypothesis of the JDCS model was found. Changes in job characteristics explained an additional 3–20% of variance in the Time 2 burnout dimensions. Specifically, high levels of emotional exhaustion at Time 2 were explained by high levels of social support at Time 1, and unfavorable changes in demands, control, and support over time; high depersonalization at Time 2 was explained by high social support at time 1 and by an increase in demands over time; and high personal accomplishment at Time 2 was predicted by high demands, high control, interactive effect demands × control × social support, at Time 1, and by a decrease in demands over time. No reversed effects of burnout on work characteristics have been found. Conclusion: Our findings suggest that

  8. Test methods for optical disk media characteristics (for 356 mm ruggedized magneto-optic media)

    NASA Technical Reports Server (NTRS)

    Podio, Fernando L.

    1991-01-01

    Standard test methods for computer storage media characteristics are essential and allow for conformance to media interchange standards. The test methods were developed for 356 mm two-sided laminated glass substrate with a magneto-optic active layer media technology. These test methods may be used for testing other media types, but in each case their applicability must be evaluated. Test methods are included for a series of different media characteristics, including operational, nonoperational, and storage environments; mechanical and physical characteristics; and substrate, recording layer, and preformat characteristics. Tests for environmental qualification and media lifetimes are also included. The best methods include testing conditions, testing procedures, a description of the testing setup, and the required calibration procedures.

  9. Shape Distribution of Fragments from Microsatellite Impact Tests

    NASA Technical Reports Server (NTRS)

    Liou, J.C.; Hanada, T.

    2009-01-01

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

  10. A Graphical Approach to Evaluating Equating Using Test Characteristic Curves

    ERIC Educational Resources Information Center

    Wyse, Adam E.; Reckase, Mark D.

    2011-01-01

    An essential concern in the application of any equating procedure is determining whether tests can be considered equated after the tests have been placed onto a common scale. This article clarifies one equating criterion, the first-order equity property of equating, and develops a new method for evaluating equating that is linked to this…

  11. 30 CFR 18.62 - Tests to determine explosion-proof characteristics.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Tests to determine explosion-proof... TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Inspections and Tests § 18.62 Tests to determine explosion-proof characteristics. (a) In testing for...

  12. 30 CFR 18.62 - Tests to determine explosion-proof characteristics.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tests to determine explosion-proof... TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Inspections and Tests § 18.62 Tests to determine explosion-proof characteristics. (a) In testing for...

  13. Target Soil Impact Verification: Experimental Testing and Kayenta Constitutive Modeling.

    SciTech Connect

    Broome, Scott Thomas; Flint, Gregory Mark; Dewers, Thomas; Newell, Pania

    2015-11-01

    This report details experimental testing and constitutive modeling of sandy soil deformation under quasi - static conditions. This is driven by the need to understand constitutive response of soil to target/component behavior upon impact . An experimental and constitutive modeling program was followed to determine elastic - plastic properties and a compressional failure envelope of dry soil . One hydrostatic, one unconfined compressive stress (UCS), nine axisymmetric compression (ACS) , and one uniaxial strain (US) test were conducted at room temperature . Elastic moduli, assuming isotropy, are determined from unload/reload loops and final unloading for all tests pre - failure and increase monotonically with mean stress. Very little modulus degradation was discernable from elastic results even when exposed to mean stresses above 200 MPa . The failure envelope and initial yield surface were determined from peak stresses and observed onset of plastic yielding from all test results. Soil elasto - plastic behavior is described using the Brannon et al. (2009) Kayenta constitutive model. As a validation exercise, the ACS - parameterized Kayenta model is used to predict response of the soil material under uniaxial strain loading. The resulting parameterized and validated Kayenta model is of high quality and suitable for modeling sandy soil deformation under a range of conditions, including that for impact prediction.

  14. Machine for development impact tests in sports seats and similar

    NASA Astrophysics Data System (ADS)

    Gonçalves, R. M.

    2015-10-01

    This paper describes the stages of development of a machine to perform impact tests in sport seats, seats for spectators and multiple seats. This includes reviews and recommendations for testing laboratories that have needs similar to the laboratory where unfolded this process.The machine was originally developed seeking to meet certain impact tests in accordance with the NBR15925 standards; 15878 and 16031. The process initially included the study of the rules and the election of the tests for which the machine could be developed and yet all reports and outcome of interaction with service providers and raw materials.For operating facility, it was necessary to set entirely the machine control, which included the concept of dialogue with operator, the design of the menu screens and the procedures for submission and registration of results. To ensure reliability in the process, the machine has been successfully calibrated according to the requirements of the Brazilian network of calibration.The criticism to this enterprise covers the technical and economic aspects involved and points out the main obstacles that were needed to overcome.

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

    SciTech Connect

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

    1999-06-01

    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.

  16. KSC lubricant testing program. [lubrication characteristics and corrosion resistance

    NASA Technical Reports Server (NTRS)

    Lockhart, B. J.; Bryan, C. J.

    1973-01-01

    A program was conducted to evaluate the performance of various lubricants in use and considered for use at Kennedy Space Center (KSC). The overall objectives of the program were to: (1) determine the lubrication characteristics and relative corrosion resistance of lubricants in use and proposed for use at KSC; (2) identify materials which may be equivalent to or better than KELF-90 and Krytox 240 AC greases; and (3) identify or develop an improved lubricating oil suitable for use in liquid oxygen (LOX) pumps at KSC. It was concluded that: (1) earth gel thickened greases are very poor corrosion preventive materials in the KSC environment; (2) Halocarbon 25-5S and Braycote 656 were suitable substiutes for KELF-90 and Krytox 240 AC respectively; and (3) none of the oils evaluated possessed the necessary inertness, lubricity, and corrosion prevention characteristics for the KSC LOX pumping systems in their present configuration.

  17. Cycom 977-2 Composite Material: Impact Test Results

    NASA Technical Reports Server (NTRS)

    Engel, Carl D.; Herald, Stephen; Watkins, Casey

    2005-01-01

    The reaction frequency data from 13A testing by MSFC and WSTF appear well behaved for the sample number used by each and exhibit the same type of energy level dependency. The reaction frequency shift in energy level is unexplained at this time. All the 13A data suggest that only a small amount of material is consumed when reactions take place. At ambient pressure, most of not all reactions are quenched as indicated by the small mass loss. As test pressure is increased in LOX using 13B results. Cycom does not support initiation of reactions or propagations of reactions in GOX at 100 psis based on tests at MSFC and WSTF at 72 ft-lb impact energy. No batch effect was identified in LOX or GOX.

  18. A Blind Test of the Younger Dryas Impact Hypothesis

    PubMed Central

    Holliday, Vance

    2016-01-01

    The Younger Dryas Impact Hypothesis (YDIH) states that North America was devastated by some sort of extraterrestrial event ~12,800 calendar years before present. Two fundamental questions persist in the debate over the YDIH: Can the results of analyses for purported impact indicators be reproduced? And are the indicators unique to the lower YD boundary (YDB), i.e., ~12.8k cal yrs BP? A test reported here presents the results of analyses that address these questions. Two different labs analyzed identical splits of samples collected at, above, and below the ~12.8ka zone at the Lubbock Lake archaeological site (LL) in northwest Texas. Both labs reported similar variation in levels of magnetic micrograins (>300 mg/kg >12.8ka and <11.5ka, but <150 mg/kg 12.8ka to 11.5ka). Analysis for magnetic microspheres in one split, reported elsewhere, produced very low to nonexistent levels throughout the section. In the other split, reported here, the levels of magnetic microspherules and nanodiamonds are low or nonexistent at, below, and above the YDB with the notable exception of a sample <11,500 cal years old. In that sample the claimed impact proxies were recovered at abundances two to four orders of magnitude above that from the other samples. Reproducibility of at least some analyses are problematic. In particular, no standard criteria exist for identification of magnetic spheres. Moreover, the purported impact proxies are not unique to the YDB. PMID:27391147

  19. A Blind Test of the Younger Dryas Impact Hypothesis.

    PubMed

    Holliday, Vance; Surovell, Todd; Johnson, Eileen

    2016-01-01

    The Younger Dryas Impact Hypothesis (YDIH) states that North America was devastated by some sort of extraterrestrial event ~12,800 calendar years before present. Two fundamental questions persist in the debate over the YDIH: Can the results of analyses for purported impact indicators be reproduced? And are the indicators unique to the lower YD boundary (YDB), i.e., ~12.8k cal yrs BP? A test reported here presents the results of analyses that address these questions. Two different labs analyzed identical splits of samples collected at, above, and below the ~12.8ka zone at the Lubbock Lake archaeological site (LL) in northwest Texas. Both labs reported similar variation in levels of magnetic micrograins (>300 mg/kg >12.8ka and <11.5ka, but <150 mg/kg 12.8ka to 11.5ka). Analysis for magnetic microspheres in one split, reported elsewhere, produced very low to nonexistent levels throughout the section. In the other split, reported here, the levels of magnetic microspherules and nanodiamonds are low or nonexistent at, below, and above the YDB with the notable exception of a sample <11,500 cal years old. In that sample the claimed impact proxies were recovered at abundances two to four orders of magnitude above that from the other samples. Reproducibility of at least some analyses are problematic. In particular, no standard criteria exist for identification of magnetic spheres. Moreover, the purported impact proxies are not unique to the YDB.

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

    ERIC Educational Resources Information Center

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

    2011-01-01

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

  1. Machine Vision Tests for Spent Fuel Scrap Characteristics

    SciTech Connect

    BERGER, W.W.

    2000-04-27

    The purpose of this work is to perform a feasibility test of a Machine Vision system for potential use at the Hanford K basins during spent nuclear fuel (SNF) operations. This report documents the testing performed to establish functionality of the system including quantitative assessment of results. Fauske and Associates, Inc., which has been intimately involved in development of the SNF safety basis, has teamed with Agris-Schoen Vision Systems, experts in robotics, tele-robotics, and Machine Vision, for this work.

  2. The impact of toxicity testing costs on nanomaterial regulation.

    PubMed

    Choi, Jae-Young; Ramachandran, Gurumurthy; Kandlikar, Milind

    2009-05-01

    Information about the toxicity of nanoparticles is important in determining how nanoparticles will be regulated. In the U.S., the burden of collecting this information and conducting risk assessment is placed on regulatory agencies without the budgetary means to carry out this mandate. In this paper, we analyze the impact of testing costs on society's ability to gather information about nanoparticle toxicity and whether such costs can reasonably be borne by an emerging industry. We show for the United States that costs for testing existing nanoparticles ranges from $249 million for optimistic assumptions about nanoparticle hazards (i.e., they are primarily safe and mainly require simpler screening assays) to $1.18 billion for a more comprehensive precautionary approach (i.e., all nanomaterials require long-term in vivo testing). At midlevel estimates of total corporate R&D spending, and assuming plausible levels of spending on hazard testing, the time taken to complete testing is likely to be very high (34-53 years) if all existing nanomaterials are to be thoroughly tested. These delays will only increase with time as new nanomaterials are introduced. The delays are considerably less if less-stringent yet risk-averse perspectives are used. Our results support a tiered risk-assessment strategy similar to the EU's REACH legislation for regulating toxic chemicals.

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

    NASA Astrophysics Data System (ADS)

    Howell, Byron Edward

    2001-12-01

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

  4. Screening Tests for Enhanced Shielding Against Hypervelocity Particle Impacts for Future Unmanned Spacecraft

    NASA Astrophysics Data System (ADS)

    Putzar, Robin; Hupfer, Jan; Aridon, Gwenaelle; Gergonne, Bernard; David, Matthieu; Bourke, Paul; Cougnet, Claude

    2013-08-01

    Protection of components of unmanned spacecraft against particle impacts is typically provided by the spacecraft's structure together with the intrinsic protection capabilities of the components themselves. Thus to increase the survivability of future spacecraft, one option is to enhance the protection already provided using enhanced materials and additional shielding. As part of the EU funded FP7 research project ReVuS ("Reducing the Vulnerability of Space systems"), the configurations of equipment typically found on board unmanned spacecraft were identified. For each of those configurations, potential solutions have been identified which enhance the robustness against particle impacts. The solutions are broken down into a number of shielding components that include e.g. additional protective layers made from aluminum, Kevlar, Nextel, stainless steel mesh and ceramics. To evaluate the characteristics and performances of these shielding components, a number of screening hypervelocity impact tests were performed. During these tests, representative configurations have been subjected to impacts of aluminum spheres of 3 mm and 5 mm diameter at a nominal impact velocity of 7 km/s. This paper describes the targets and presents and compares the results.

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

    ERIC Educational Resources Information Center

    Wilde, Elizabeth Ty; Hollister, Robinson

    2002-01-01

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

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

    ERIC Educational Resources Information Center

    Wilde, Elizabeth Ty; Hollister, Robinson

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

  7. Dynamic Open-Rotor Composite Shield Impact Test Report

    NASA Technical Reports Server (NTRS)

    Seng, Silvia; Frankenberger, Charles; Ruggeri, Charles R.; Revilock, Duane M.; Pereira, J. Michael; Carney, Kelly S.; Emmerling, William C.

    2015-01-01

    The Federal Aviation Administration (FAA) is working with the European Aviation Safety Agency to determine the certification base for proposed new engines that would not have a containment structure on large commercial aircraft. Equivalent safety to the current fleet is desired by the regulators, which means that loss of a single fan blade will not cause hazard to the aircraft. NASA Glenn and Naval Air Warfare Center (NAWC) China Lake collaborated with the FAA Aircraft Catastrophic Failure Prevention Program to design and test a shield that would protect the aircraft passengers and critical systems from a released blade that could impact the fuselage. This report documents the live-fire test from a full-scale rig at NAWC China Lake. NASA provided manpower and photogrammetry expertise to document the impact and damage to the shields. The test was successful: the blade was stopped from penetrating the shield, which validates the design analysis method and the parameters used in the analysis. Additional work is required to implement the shielding into the aircraft.

  8. The Impact of Youth Risk on Mentoring Relationship Quality: Do Mentor Characteristics Matter?

    PubMed

    Raposa, Elizabeth B; Rhodes, Jean E; Herrera, Carla

    2016-06-01

    Although mentoring is a widely used intervention strategy, effect sizes for at-risk youth remain modest. Research is therefore needed to maximize the impact of mentoring for at-risk youth who might struggle to benefit from mentoring relationships. This study tested the hypothesis that different types of youth risk would have a negative impact on mentoring relationship quality and duration and explored whether mentor characteristics exacerbated or mitigated these negative effects. Results showed that elevated environmental stress at a youth's home and/or school predicted shorter match duration, and elevated rates of youth behavioral problems, such as poor academic performance or misconduct, predicted greater youth dissatisfaction and less positive mentor perceptions of relationship quality. Mentors with greater self-efficacy and more previous involvement with youth in their communities were able to buffer the negative effects of environmental stress on match duration. Similarly, mentors' previous involvement with youth buffered the negative effects of youth behavioral problems on mentor perceptions of relationship quality. Findings have important implications for the matching of mentors and at-risk youth in a way that improves mentoring outcomes.

  9. Reconstruction of dynamic forces during impact tests of a crushable structure

    SciTech Connect

    Bateman, V.I.; Carne, T.G.; Mayes, R.L.; Davie, N.T.

    1993-12-31

    A force reconstruction technique is being used to assess the dynamic performance of a crushable structure (a bomb nose) in both the axial (90{degree}) and slapdown (30{degree}) impact conditions. The dynamic force characteristics for the current nose design, determined from these tests, will be used to write a dynamic force specification for a new nose design that will replace the current nose. Two structures for experimentally determining the dynamic force -- deflection characteristics of the old and new noses have been designed and constructed. One structure has the same dynamic characteristics as the bomb and is being used for axial and slapdown orientations with rocket-propelled testing. The second structure has the same mass as the bomb and is being used for iterative axial testing of candidate designs with a pneumatic ram. The structural characteristics of these two structures have been determined and are presented. A force reconstruction algorithm using the Sum of Weighted Accelerations Technique (SWAT) has been developed for each of the two structures. The force reconstruction algorithms have been verified for both structures using laboratory data. The force reconstruction process and the resulting algorithms are described. Data verifying the force reconstruction algorithms is presented.

  10. Landing Characteristics of the Apollo Spacecraft with Deployed Heat Shield Impact Attenuation System

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Landing Characteristics of the Apollo Spacecraft with Deployed Heat Shield Impact Attenuation Systems. An experimental investigation was made to determine the landing characteristics of a 1/4-scale dynamic model of the Apollo spacecraft command module using two different active (heat shield deployed prior to landing) landing systems for impact attenuation. One landing system (configuration 1) consisted of six hydraulic struts and eight crushable honeycomb struts. The other landing system (configuration 2), consisted of four hydraulic struts and six strain straps. Tests made on water and the hard clay-gravel composite landing surfaces simulated parachute letdown (vertical) velocities of 23 ft/sec (7.0 m/s) (full scale). Landings made on the sand landing surface simulated vertical velocities of 30 ft/sec (9.1 m/s). Horizontal velocities of from 0 to 50 ft/sec (15 m/s) were simulated. Landing attitudes ranged from -30'degrees to 20 degrees, and the roll attitudes were O degrees, 90 degrees, and 180 degrees. For configuration 1, maximum normal accelerations at the vehicle center of gravity for landings on water, sand, and the hard clay-gravel composite surface were 9g, 20g, and 18g, respectively. The maximum normal center-of-gravity acceleration for configuration 2 which was landed only on the hard clay-gravel landing surface was approximately 19g. Accelerations for configuration 2 were generally equal to or lower than accelerations for configuration 1 and normal. [Entire movie available on DVD from CASI as Doc ID 20070030975. Contact help@sti.nasa.gov

  11. Water impact testing of a filament wound case

    NASA Technical Reports Server (NTRS)

    Schmidt, A. A.; Kross, D. A.

    1985-01-01

    A lightweight Filament Wound Case (FWC) Solid Rocket Booster (SRB) is being developed by NASA to increase the payload capability of the space shuttle. As with the steel boosters, the current plan is to recover the FWC SRB's after they impact the ocean at 65 to 85 ft/sec. As the boosters enter the ocean (nozzle first) the water moves away from the vehicle creating a cavity, which then collapses on the vehicle, and results in a significant loading event. To understand this loading event, tests were conducted on a quarter scale FWC model to measure cavity collapse pressure distributions, deflected shape and the effects of end conditions and pressure scaling.

  12. Power-crowbar impacts on plasma characteristics in ZT-40

    SciTech Connect

    Watt, R.G.

    1981-07-01

    Detailed analysis of the impact of I/sub phi/ and I/sub theta/ power crowbars on the ZT-40 plasma is presented for the operational period between shots 1620-3600. It is demonstrated that in both aided- and self-reversed modes the main effect of the I/sub phi/ power crowbar is to lengthen the time to l/e of peak current, whereas the main effect of the I/sub theta/ power crowbar is to extend the reversal of B/sub phi/ at the wall, primarily in self-reversed operation. It is shown that this extension has the effect of also decreasing the current decay rate to the point where no distinction is seen between the two modes. A saturation is seen in the decay time (tau/sub l/e/ less than or equal to 0.4 ms) once the field reversal in either mode exceeds approximately 0.3 ms. Possible physical explanations of these effects are discussed.

  13. Alexithymic characteristics in responses to the Synthetic House-Tree-Person (HTP) Drawing Test.

    PubMed

    Fukunishi, I; Mikami, N; Kikuchi, M

    1997-12-01

    This study examined the association of certain complex personality traits assessed by the Synthetic House-Tree-Person Drawing Test and alexithymic characteristics assessed by the 20-item Toronto Alexithymia Scale for a sample of 589 Japanese college students. Alexithymic students who scored over 61 points on the Toronto Alexithymia Scale-20 exhibited two characteristics relative to the test: poor relationships between figures and additional written explanations. These two characteristics projected on the Synthetic House-Tree-Person Drawing Test may be related to alexithymic characteristics and related factors.

  14. Description, characteristics and testing of the NASA airborne radar

    NASA Technical Reports Server (NTRS)

    Jones, W. R.; Altiz, O.; Schaffner, P.; Schrader, J. H.; Blume, H. J. C.

    1991-01-01

    Presented here is a description of a coherent radar scattermeter and its associated signal processing hardware, which have been specifically designed to detect microbursts and record their radar characteristics. Radar parameters, signal processing techniques and detection algorithms, all under computer control, combine to sense and process reflectivity, clutter, and microburst data. Also presented is the system's high density, high data rate recording system. This digital system is capable of recording many minutes of the in-phase and quadrature components and corresponding receiver gains of the scattered returns for selected spatial regions, as well as other aircraft and hardware related parameters of interest for post-flight analysis. Information is given in viewgraph form.

  15. Headache at high school: clinical characteristics and impact.

    PubMed

    Tonini, M C; Frediani, F

    2012-05-01

    Although migraine (MH) and tension type headache (TTH) are the most common and important causes of recurrent headache in adolescents, they are poorly understood and not recognized by parents and teachers, delaying the first physician evaluation for correct diagnosis and management. The purpose of this study is to assess the knowledge about headache impact among the students of a Communication Private High School in Rimini city, and to evaluate the main different types of headaches interfering with school and social day activities. A self-administered questionnaire interview was given to students of the last 2 years of high school; ten items assessed the headache experience during the prior 12 months, especially during school time: the features and diagnosis of headaches types (based on the 2004 IHS criteria), precipitating factors, disability measured using the migraine disability assessment (MIDAS); therapeutic intervention. Out of the 60 students, 84 % experienced recurrent headache during the last 12 months. 79 % were females, aged 17-20 years; a family history was present in 74 % of headache students, in the maternal line; 45 % of subjects were identified as having MH and 27 % TTH; 25 % had morning headache and 20 % in the afternoon; fatigue, emotional stress and lack of sleep were the main trigger factors for headache, respectively in 86, 50 and 50 % of students; 92 % of headache students could not follow the lessons, could not participate in exercises and physical activity because of the headache; none had consulted a medical doctor and the 90 % of all students had never read, listened or watched television about headache. This study remarks on the need to promote headache educational programs, starting from high school, to increase communication between teachers-family-physician and patient-adolescents, with the goal to have an early appropriate therapeutic intervention, improvement of the quality of life and to prevent long-term headache disease in the

  16. Design characteristics of a heat pipe test chamber

    NASA Technical Reports Server (NTRS)

    Baker, Karl W.; Jang, J. Hoon; Yu, Juin S.

    1992-01-01

    LeRC has designed a heat pipe test facility which will be used to provide data for validating heat pipe computer codes. A heat pipe test chamber that uses helium gas for enhancing heat transfer was investigated. The conceptual design employs the technique of guarded heating and guarded cooling to facilitate accurate measurements of heat transfer rates to the evaporator and from the condenser. The design parameters are selected for a baseline heat pipe made of stainless steel with an inner diameter of 38.10 mm and a wall thickness of 1.016 mm. The heat pipe operates at a design temperature of 1000 K with an evaporator radial heat flux of 53 W/sq. cm.

  17. Impact of aging on leaching characteristics of recycled concrete aggregate.

    PubMed

    Abbaspour, Aiyoub; Tanyu, Burak F; Cetin, Bora

    2016-10-01

    The focus of this study was to evaluate the effects of stockpiling (aging) on leaching of elements in recycled concrete aggregate (RCA) that may contribute to tufaceous constituent formation. Speciation and leaching controlling mechanisms of these elements were identified via geochemical modeling. The effects of stockpiling were simulated by comparing freshly produced RCA with RCA aged as part of this study for 1 year both in the laboratory and in the field. Leachate samples were generated following batch water leach test (WLT) and US Geological Survey leach test (USGSLT) methods. USGSLTs were conducted both on the laboratory and field samples while WLT was only conducted on laboratory samples. During the laboratory aging, it is observed that the carbonate content of RCA, measured as calcite equivalent, increased 20 % (i.e., from ∼100 to 120 mg/g) within a year time frame. The leachate extracted from RCA showed minor changes in pH and more significant decreases in electrical conductivity (i.e., ∼300 to 100 μS/cm). A comparison between laboratory and field samples revealed that the RCA aged much slower in the field than in the laboratory within a year. Comparisons between two leach extraction methods on the laboratory conditions showed that the total leached concentrations (TLCs) of most of the constituents from USGSLT were appreciably lower than the ones measured via WLT method. The results of geochemical modeling analyses showed that Al, Si, Fe, Ca, Mg, and Cu exist in their oxidized forms as Al(3+), Fe(3+), Si(4+), Ca(2+), Mg(2+), and Cu(2+) and results revealed that these elements are primarily controlled by the solubility of gibbsite, hematite, silica gel, calcite, magnesite, and tenorite solid phases, respectively. One of the significant findings of the study was to identify the changes in leaching behavior of Ca, Si, Mg, Al, Fe, and Cu due to carbonation.

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

    SciTech Connect

    Lee, Sanghoon; Cho, Sang-Soon; Kim, Ki-Young; Jeon, Je-Eon; Seo, Ki-Seog

    2013-07-01

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

  19. Characteristics of lithium-ion batteries during fire tests

    NASA Astrophysics Data System (ADS)

    Larsson, Fredrik; Andersson, Petra; Blomqvist, Per; Lorén, Anders; Mellander, Bengt-Erik

    2014-12-01

    Commercial lithium-ion battery cells are exposed to a controlled propane fire in order to evaluate heat release rate (HRR), emission of toxic gases as well as cell temperature and voltage under this type of abuse. The study includes six abuse tests on cells having lithium-iron phosphate (LFP) cathodes and, as a comparison, one test on conventional laptop battery packs with cobalt based cathode. The influence of different state of charge (SOC) is investigated and a limited study of the effect of water mist application is also performed. The total heat release (THR) per battery energy capacity are determined to be 28-75 kJ Wh-1 and the maximum HRR values to 110-490 W Wh-1. Hydrogen fluoride (HF) is found in the released gases for all tests but no traceable amounts of phosphorous oxyfluoride (POF3) or phosphorus pentafluoride (PF5) are detected. An extrapolation of expected HF emissions for a typical automotive 10 kWh battery pack exposed to fire gives a release of 400-1200 g HF. If released in a confined environment such emissions of HF may results in unacceptable exposure levels.

  20. Controlled Impact Demonstration instrumented test dummies installed in plane

    NASA Technical Reports Server (NTRS)

    1984-01-01

    In this photograph are seen some of dummies in the passenger cabin of the B-720 aircraft. NASA Langley Research Center instrumented a large portion of the aircraft and the dummies for loads in a crashworthiness research program. In 1984 NASA Dryden Flight Research Facility and the Federal Aviation Adimistration (FAA) teamed-up in a unique flight experiment called the Controlled Impact Demonstration (CID). The test involved crashing a Boeing 720 aircraft with four JT3C-7 engines burning a mixture of standard fuel with an additive called Anti-misting Kerosene (AMK) designed to supress fire. In a typical aircraft crash, fuel spilled from ruptured fuel tanks forms a fine mist that can be ignited by a number of sources at the crash site. In 1984 the NASA Dryden Flight Research Facility (after 1994 a full-fledged Center again) and the Federal Aviation Administration (FAA) teamed-up in a unique flight experiment called the Controlled Impact Demonstration (CID), to test crash a Boeing 720 aircraft using standard fuel with an additive designed to supress fire. The additive, FM-9, a high-molecular-weight long-chain polymer, when blended with Jet-A fuel had demonstrated the capability to inhibit ignition and flame propagation of the released fuel in simulated crash tests. This anti-misting kerosene (AMK) cannot be introduced directly into a gas turbine engine due to several possible problems such as clogging of filters. The AMK must be restored to almost Jet-A before being introduced into the engine for burning. This restoration is called 'degradation' and was accomplished on the B-720 using a device called a 'degrader.' Each of the four Pratt & Whitney JT3C-7 engines had a 'degrader' built and installed by General Electric (GE) to break down and return the AMK to near Jet-A quality. In addition to the AMK research the NASA Langley Research Center was involved in a structural loads measurement experiment, which included having instrumented dummies filling the seats in the

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

    PubMed

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

    2015-07-01

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

  2. Radioactivation characteristics for the tokamak fusion test reactor

    SciTech Connect

    Ku, L.; Kolibal, J.G.

    1983-11-01

    Activation analysis has been conducted for several primary fusion blanket materials based on a model of a commercial tokamak fusion reactor design, STARFIRE. The blanket materials studied include two solid tritium breeders, viz., Li/sub 2/O and ..cap alpha..-LiAlO/sub 2/, and four candidate structural materials, viz., PCA stainless steel, V15Cr5Ti, Ti6Al4V, and Al-6063 alloys. The importance of breeder material activation is identified in terms of its impurity contents such as potassium, iron, nickel, molybdenum, and zirconium trace elements. The breeder activation is also discussed with regard to its potential for recycling and its impact on the lithium resource requirements. The structural material activation is analyzed based on two measures, volumetric radioactivity concentration and contact biological dose due to decay gamma emission. Using the radioactivity concentration measure, it is revealed that a substantial advantage exists from a viewpoint of radwaste management, which is inherent in fusion reactor designs based on potential low-activation alloys such as V15Cr5Ti, Ti6Al4V, and Al-6063. On the other hand, from the dose standpoint, the V15Cr5Ti alloy is found to be the only alloy for which one could realize a significant dose reduction (below 2.5 mrem/h) within about 100 yr after shutdown, possibly by some extrapolation on alloy purification techniques.

  3. NEXT Long-Duration Test Neutralizer Performance and Erosion Characteristics

    NASA Technical Reports Server (NTRS)

    Herman, Daniel A.; Soulas, George C.; Patterson, Michael J.

    2009-01-01

    The NASA's Evolutionary Xenon Thruster (NEXT) program is developing the next-generation ion propulsion system with significant enhancements beyond the state-of-the-art to provide future NASA science missions with enhanced capabilities at a low total development cost. A Long-Duration Test (LDT) was initiated in June 2005, to verify the NEXT propellant throughput capability to a qualification-level of 450 kg, 1.5 times the anticipated throughput requirement of 300 kg per thruster based on mission analyses. As of September 2, 2009, the thruster has accumulated 24,400 hr of operation with extensive durations at the following input powers: 6.9, 4.7, 1.1, and 0.5 kW. The thruster has processed 434 kg of xenon, surpassing the NASA Solar Technology Application Readiness (NSTAR) program thruster propellant throughput demonstrated during the extended life testing of the Deep Space 1 flight spare ion thruster and approaching the NEXT development qualification throughput goal of 450 kg. The NEXT LDT has demonstrated a total impulse of 16.1 10(exp 6zzz0 N s; the highest total impulse ever demonstrated by an ion thruster. A reduction in neutralizer flow margin has been the only appreciable source of thruster performance degradation. The behavior of the neutralizer is not easily predicted due to both erosion and deposition observed in previous wear tests. Spot-to-plume mode transition flow data and in-situ erosion results for the LDT neutralizer are discussed. This loss of flow margin has been addressed through a combination of a design change in the prototype-model neutralizer to increase flow margin at low emission current and to update the NEXT throttle table to ensure adequate flow margin as a function of propellant throughput processed. The new throttle table will be used for future LDT operations. The performance of the NEXT LDT neutralizer is consistent with that observed for long-life hollow cathodes. The neutralizer life-limiting failure modes are progressing as expected

  4. Associations of hospital characteristics with nosocomial pneumonia after cardiac surgery can impact on standardized infection rates.

    PubMed

    Sanagou, M; Leder, K; Cheng, A C; Pilcher, D; Reid, C M; Wolfe, R

    2016-04-01

    To identify hospital-level factors associated with post-cardiac surgical pneumonia for assessing their impact on standardized infection rates (SIRs), we studied 43 691 patients in a cardiac surgery registry (2001-2011) in 16 hospitals. In a logistic regression model for pneumonia following cardiac surgery, associations with hospital characteristics were quantified with adjustment for patient characteristics while allowing for clustering of patients by hospital. Pneumonia rates varied from 0·7% to 12·4% across hospitals. Seventy percent of variability in the pneumonia rate was attributable to differences in hospitals in their long-term rates with the remainder attributable to within-hospital differences in rates over time. After adjusting for patient characteristics, the pneumonia rate was found to be higher in hospitals with more registered nurses (RNs)/100 intensive-care unit (ICU) admissions [adjusted odds ratio (aOR) 1·2, P = 0·006] and more RNs/available ICU beds (aOR 1·4, P < 0·001). Other hospital characteristics had no significant association with pneumonia. SIRs calculated on the basis of patient characteristics alone differed substantially from the same rates calculated on the basis of patient characteristics and the hospital characteristic of RNs/100 ICU admissions. Since SIRs using patient case-mix information are important for comparing rates between hospitals, the additional allowance for hospital characteristics can impact significantly on how hospitals compare.

  5. Experimental impact testing and analysis of composite fan cases

    NASA Astrophysics Data System (ADS)

    Vander Klok, Andrew Joe

    For aircraft engine certification, one of the requirements is to demonstrate the ability of the engine to withstand a fan blade-out (FBO) event. A FBO event may be caused by fatigue failure of the fan blade itself or by impact damage of foreign objects such as bird strike. An un-contained blade can damage flight critical engine components or even the fuselage. The design of a containment structure is related to numerous parameters such as the blade tip speed; blade material, size and shape; hub/tip diameter; fan case material, configuration, rigidity, etc. To investigate all parameters by spin experiments with a full size rotor assembly can be prohibitively expensive. Gas gun experiments can generate useful data for the design of engine containment cases at much lower costs. To replicate the damage modes similar to that on a fan case in FBO testing, the gas gun experiment has to be carefully designed. To investigate the experimental procedure and data acquisition techniques for FBO test, a low cost, small spin rig was first constructed. FBO tests were carried out with the small rig. The observed blade-to-fan case interactions were similar to those reported using larger spin rigs. The small rig has the potential in a variety of applications from investigating FBO events, verifying concept designs of rotors, to developing spin testing techniques. This rig was used in the developments of the notched blade releasing mechanism, a wire trigger method for synchronized data acquisition, high speed video imaging and etc. A relationship between the notch depth and the release speed was developed and verified. Next, an original custom designed spin testing facility was constructed. Driven by a 40HP, 40,000rpm air turbine, the spin rig is housed in a vacuum chamber of phi72inx40in (1829mmx1016mm). The heavily armored chamber is furnished with 9 viewports. This facility enables unprecedented investigations of FBO events. In parallel, a 15.4ft (4.7m) long phi4.1inch (105mm

  6. Effect of Curvature on the Impact Damage Characteristics and Residual Strength of Composite Plates

    NASA Technical Reports Server (NTRS)

    Ambur, Damodar R.; Starnes, James H., Jr.

    1998-01-01

    The results of a study of the response and failure characteristics of thin, cylindrically curved, composite plates subjected to low-speed impact damage are presented. The results indicate that the plate radius and the plate thickness are important structural parameters that influence the nonlinear response of a plate for a given amount of impact energy. Analytical and experimental contact-force results are compared for several plates and the results correlate well. The impact-energy levels required to cause damage initiation and barely visible impact damage are a function of the plate radius for a given plate thickness. The impact-energy levels required to initiate impact damage for plates with a certain range of radii are greater than plates with other radii. The contact-force results corresponding to these impact-energy levels follow a similar trend. Residual strength results for plates with barely visible impact damage suggest that the compression-after-impact residual strength is also a function of plate radius. The residual strength of impact-damaged flat plates appears to be lower than the residual strength of the corresponding cylindrically curved plates.

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

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

    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.

  8. The aerodynamic characteristics of eight very thick airfoils from tests in the variable density wind tunnel

    NASA Technical Reports Server (NTRS)

    Jacobs, Eastman N

    1932-01-01

    Report presents the results of wind tunnel tests on a group of eight very thick airfoils having sections of the same thickness as those used near the roots of tapered airfoils. The tests were made to study certain discontinuities in the characteristic curves that have been obtained from previous tests of these airfoils, and to compare the characteristics of the different sections at values of the Reynolds number comparable with those attained in flight. The discontinuities were found to disappear as the Reynolds number was increased. The results obtained from the large-scale airfoil, a symmetrical airfoil having a thickness ratio of 21 per cent, has the best general characteristics.

  9. RTM370 Polyimide Braided Composites: Characterization and Impact Testing

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  10. Current status of small specimen technology in Charpy impact testing

    NASA Astrophysics Data System (ADS)

    Kurishita, H.; Kayano, H.; Narui, M.; Yamazaki, M.

    1994-09-01

    The current status of small-scale specimen technology in Charpy impact testing for ferritic steels is presented, with emphasis on the effect of the notch dimensions (notch depth, notch root radius and notch angle) on the upper shelf energy (USE) and ductile-to-brittle transition temperature (DBTT). The USE for miniaturized specimens, normalized by Bb2 or ( Bb{3}/{2} ( B is the specimen thickness, b the ligament size), is essentially independent of notch geometry and has a linear relationship with the USE of full size specimens, regardless of irradiation and alloy conditions. The DBTT of miniaturized specimens depends strongly on the notch dimensions; this dependence of the DBTT decreases as the DBTT of full size specimens increase due to neutron irradiation or thermal aging. These results may be useful in determining the USE and DBTT for full size specimens from those for miniaturized specimens.

  11. IMPROVED BAR IMPACT TESTS USING A PHOTONIC DOPPLER VELOCIMETER

    SciTech Connect

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

    2009-12-28

    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.

  12. IMPROVED BAR IMPACT TESTS USING A PHOTONIC DOPPLER VELOCIMETER

    SciTech Connect

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

    2009-08-24

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

  13. Quantitative testing of robustness on superomniphobic surfaces by drop impact.

    PubMed

    Nguyen, Thi Phuong Nhung; Brunet, Philippe; Coffinier, Yannick; Boukherroub, Rabah

    2010-12-07

    The quality of a liquid-repellent surface is quantified by both the apparent contact angle θ(0) that a sessile drop adopts on it and the value of the liquid pressure threshold the surface can withstand without being impaled by the liquid, hence maintaining a low-friction condition. We designed surfaces covered with nanowires obtained by the vapor-liquid-solid (VLS) growth technique that are able to repel most of the existing nonpolar liquids including those with very low surface tension as well as many polar liquids with moderate to high surface tension. These superomniphobic surfaces exhibit apparent contact angles ranging from 125 to 160° depending on the liquid. We tested the robustness of the surfaces against impalement by carrying out drop impact experiments. Our results show how this robustness depends on Young's contact angle θ(0) related to the surface tension of the liquid and that the orientational growth of nanowires is a favorable factor for robustness.

  14. Psychometric Characteristics of Single-Word Tests of Children's Speech Sound Production

    ERIC Educational Resources Information Center

    Flipsen, Peter, Jr.; Ogiela, Diane A.

    2015-01-01

    Purpose: Our understanding of test construction has improved since the now-classic review by McCauley and Swisher (1984) . The current review article examines the psychometric characteristics of current single-word tests of speech sound production in an attempt to determine whether our tests have improved since then. It also provides a resource…

  15. Impact of polymer surface characteristics on the microrheological measurement quality of protein solutions - A tracer particle screening.

    PubMed

    Bauer, Katharina Christin; Schermeyer, Marie-Therese; Seidel, Jonathan; Hubbuch, Jürgen

    2016-05-30

    Microrheological measurements prove to be suitable to identify rheological parameters of biopharmaceutical solutions. These give information about the flow characteristics but also about the interactions and network structures in protein solutions. For the microrheological measurement tracer particles are required. Due to their specific surface characteristic not all are suitable for reliable measurement results in biopharmaceutical systems. In the present work a screening of melamine, PMMA, polystyrene and surface modified polystyrene as tracer particles were investigated at various protein solution conditions. The surface characteristics of the screened tracer particles were evaluated by zeta potential measurements. Furthermore each tracer particle was used to determine the dynamic viscosity of lysozyme solutions by microrheology and compared to a standard. The results indicate that the selection of the tracer particle had a strong impact on the quality of the microrheological measurement dependent on pH and additive type. Surface modified polystyrene was the only tracer particle that yielded good microrheological results for all tested conditions. The study indicated that the electrostatic surface charge of the tracer particle had a minor impact than its hydrophobicity. This characteristic was the crucial surface property that needs to be considered for the selection of a suitable tracer particle to achieve high measurement accuracy.

  16. Eddy current nondestructive testing device for measuring variable characteristics of a sample utilizing Walsh functions

    DOEpatents

    Libby, Hugo L.; Hildebrand, Bernard P.

    1978-01-01

    An eddy current testing device for measuring variable characteristics of a sample generates a signal which varies with variations in such characteristics. A signal expander samples at least a portion of this generated signal and expands the sampled signal on a selected basis of square waves or Walsh functions to produce a plurality of signal components representative of the sampled signal. A network combines these components to provide a display of at least one of the characteristics of the sample.

  17. Accelerated life testing and temperature dependence of device characteristics in GaAs CHFET devices

    NASA Technical Reports Server (NTRS)

    Gallegos, M.; Leon, R.; Vu, D. T.; Okuno, J.; Johnson, A. S.

    2002-01-01

    Accelerated life testing of GaAs complementary heterojunction field effect transistors (CHFET) was carried out. Temperature dependence of single and synchronous rectifier CHFET device characteristics were also obtained.

  18. Diversity of TiO2 nanopowders' characteristics relevant to toxicity testing

    NASA Astrophysics Data System (ADS)

    Novak, Saša; Lorenzetti, Martina; Drame, Anja; Vidmar, Janja; Ščančar, Janez; Filipič, Metka

    2016-05-01

    In this study, the physicochemical properties of several commercial ultrafine TiO2 powders and their behaviour in the as-received form and colloidal suspensions were analysed. Besides the particle size, the morphology and agglomeration state of the dry powders, dispersibility, ζ-potential and sedimentation in water and in phosphate-buffered saline (PBS) were studied. Also, leaching of ions from the powders during ageing in physiological solution and the ability of the photoactivated powders to decompose organic substances were evaluated. The examined TiO2 powders revealed diversified characteristics when dispersed in water. In general, while in dry conditions the particle size appeared in the nano-range (down to 32 nm), the particles were agglomerated in aqueous suspensions at pH 7 and only a minor amount showed dimensions below 200 nm, but none below 100 nm. The inherent pH of the 3 % suspensions varies from 3.7 to 7.5 and the surface charge at these pH values varied from highly positive to highly negative values. In PBS, the surface charge is negative and relatively low for all the samples, which resulted in agglomeration. Five out of six powders exhibited significant photocatalytic activity when exposed to UV irradiation. This also includes one cosmetic-grade powder. Furthermore, during the immersion in aqueous media at physiological temperature, the powders released foreign ions, which might also contribute to the results of cytotoxicity tests. The results revealed the major role of the particle surface charge and its impact on particle dispersion or agglomeration. Due to the high ionic strength in the liquids relevant for cell-surface interaction tests, for all the examined titania powders the nanoparticulate character was lost. However, the presence of impurities and photocatalysis might further contribute to the results of cytotoxicity tests.

  19. Phenomenological Characteristics, Social Problems, and the Economic Impact Associated with Chronic Skin Picking

    ERIC Educational Resources Information Center

    Flessner, Christopher A.; Woods, Douglas W.

    2006-01-01

    In this study, the authors collected data on the demographic characteristics, phenomenology, and social and economic impact of skin picking. A total of 92 participants completed an anonymous, Internet-based survey through a link to the Trichotillomania Learning Center's home page. Results indicated that skin pickers experienced social,…

  20. Observed Characteristics and Teacher Quality: Impacts of Sample Selection on a Value Added Model

    ERIC Educational Resources Information Center

    Winters, Marcus A.; Dixon, Bruce L.; Greene, Jay P.

    2012-01-01

    We measure the impact of observed teacher characteristics on student math and reading proficiency using a rich dataset from Florida. We expand upon prior work by accounting directly for nonrandom attrition of teachers from the classroom in a sample selection framework. We find evidence that sample selection is present in the estimation of the…

  1. Impact of environmental factors on the demographic characteristics in Tomsk Oblast (Russia, 1980-2015)

    NASA Astrophysics Data System (ADS)

    Pugacheva, E.; Mezhibor, A.; Makarenko, T.

    2016-09-01

    The research represents the analysis of essential demographic indexes in Tomsk Oblast (Russia): birth-rate, death-rate, natural increase (1980-2015), migration increase (19972014), and child mortality (1990-2015). Environmental factors were determined as influencing the health and as a consequence, having the impact on the demographic characteristics of the studied region.

  2. Dynamics of the physicotechnical characteristics of a metal during impact strengthening of its surface

    NASA Astrophysics Data System (ADS)

    Gradov, O. M.

    2015-12-01

    Based on the laws of conservation of energy and momentum, equations of the evolution of metal characteristics during impact strengthening of its surface have been deduced. The conditions of the optimal mode of treatment are determined and its effective time is estimated. The experimental data agree fairly well with the results of the equation solutions.

  3. Low temperature impact testing of welded structural wrought iron

    NASA Astrophysics Data System (ADS)

    Rogers, Zachary

    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

  4. Impact of experimental hypercalcemia on routine haemostasis testing

    PubMed Central

    Lippi, Giuseppe; Salvagno, Gian Luca; Brocco, Giorgio; Gelati, Matteo; Favaloro, Emmanuel J.

    2017-01-01

    Background The blood to anticoagulant ratio is standardized according to the physiological calcium concentration in blood samples conventionally used for hemostasis testing. Specifically, one fixed volume of 0.109 mmol/L sodium citrate is added to 9 volumes of blood. Since little is known about the impact of hypercalcemia on the calcium-binding capacity of citrate, this study was planned to investigate the effect of experimental hypercalcemia on routine hemostasis testing. Methods Fifteen pooled citrated plasmas with matching lithium-heparin pooled plasma from patients with different values of prothrombin time (PT) were divided in three aliquots of 0.6mL each. The first paired aliquots of both citrate and lithium-heparin plasma were supplemented with 60μL of saline, the second paired aliquots with 30μL of saline and 30μL of calcium chloride and the third paired aliquots with 60μL of calcium chloride. Total and ionized calcium was measured in all aliquots of citrate and lithium-heparin plasma, whereas PT, activated partial thromboplastin time (APTT) and fibrinogen were measured in citrate plasma aliquots. Results Total calcium concentration gradually increased in both lithium-heparin and citrate plasma aliquots 2 and 3 compared to baseline aliquot 1. The concentration of ionized calcium also gradually increased in lithium-heparin plasma aliquots 2 and 3, whereas it remained immeasurable (i.e., <0.10 mmol/L) in all citrate plasma aliquots. No significant differences were observed for values of PT, APTT and fibrinogen in citrate plasma aliquots 2 and 3 compared to the baseline aliquot 1, with a mean bias was always comprised within the desirable quality specifications derived from biological variability data. Conclusion Hypercalcemia, up to severe hypercalcemia does not generate significant bias in results of first-line coagulations tests, so that hypothetical consideration of adjusting citrate-blood ratio is unjustified in hypercalcemic patients. PMID:28362859

  5. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Knees and knee impact test procedure. 572.166... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N)....

  6. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Knees and knee impact test procedure. 572.166... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N)....

  7. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 7 2012-10-01 2012-10-01 false Knees and knee impact test procedure. 572.166... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N)....

  8. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 7 2014-10-01 2014-10-01 false Knees and knee impact test procedure. 572.166... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N)....

  9. 49 CFR 572.166 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Knees and knee impact test procedure. 572.166... Hybrid III Six-Year-Old Weighted Child Test Dummy § 572.166 Knees and knee impact test procedure. The knee assembly is assembled and tested as specified in 49 CFR 572.126 (Subpart N)....

  10. Proposed minimum requirements for the operational characteristics and testing of submersible atmosphere monitoring and control units.

    PubMed

    Kirk, J C

    1998-01-01

    The design of a submersible and its myriad subsystems is a complex undertaking made more difficult by the interval between new designs. Special applications also tax the life support designer, such as diver lock-out submersibles, which are far more complex than one-atmosphere vehicles. The long intervals between designs generally means that a new generation of designers will be approaching the problems without the benefit of the knowledge and experience of the past generation of designers. This new generation of designers often has greatly improved technologies and materials at hand. Yet in the application of the new technology, life support issues that were addressed and resolved in the old and proven designs get lost in the process of redesign due to the lack of experience in the life support arena. Competent engineers operating outside their normal area of expertise can generate costly or even deadly mistakes. For this reason a set of performance requirements that details the critical functions of the life support systems is needed. Atmosphere control electronics can seriously impact the safety of the submersible crew. The triple dangers of fire, toxicity, and asphyxia demand that the electronics that monitor and control the submarine compartment atmosphere have certain characteristics. These characteristics are easily captured in a performance requirement. This article will present a set of proposed minimum performance requirements, with the goal of establishing a dialog for the creation of guidelines for the classification, rating, design, and testing of embedded electronics for life support systems used in submersible applications. These guidelines will serve as the foundation for the later creation of a set of industry specifications.

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

    NASA Technical Reports Server (NTRS)

    1976-01-01

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

  12. Vaccination Programs for Endemic Infections: Modelling Real versus Apparent Impacts of Vaccine and Infection Characteristics

    NASA Astrophysics Data System (ADS)

    Ragonnet, Romain; Trauer, James M.; Denholm, Justin T.; Geard, Nicholas L.; Hellard, Margaret; McBryde, Emma S.

    2015-10-01

    Vaccine effect, as measured in clinical trials, may not accurately reflect population-level impact. Furthermore, little is known about how sensitive apparent or real vaccine impacts are to factors such as the risk of re-infection or the mechanism of protection. We present a dynamic compartmental model to simulate vaccination for endemic infections. Several measures of effectiveness are calculated to compare the real and apparent impact of vaccination, and assess the effect of a range of infection and vaccine characteristics on these measures. Although broadly correlated, measures of real and apparent vaccine effectiveness can differ widely. Vaccine impact is markedly underestimated when primary infection provides partial natural immunity, when coverage is high and when post-vaccination infectiousness is reduced. Despite equivalent efficacy, ‘all or nothing’ vaccines are more effective than ‘leaky’ vaccines, particularly in settings with high risk of re-infection and transmissibility. Latent periods result in greater real impacts when risk of re-infection is high, but this effect diminishes if partial natural immunity is assumed. Assessments of population-level vaccine effects against endemic infections from clinical trials may be significantly biased, and vaccine and infection characteristics should be considered when modelling outcomes of vaccination programs, as their impact may be dramatic.

  13. Vaccination Programs for Endemic Infections: Modelling Real versus Apparent Impacts of Vaccine and Infection Characteristics

    PubMed Central

    Ragonnet, Romain; Trauer, James M.; Denholm, Justin T.; Geard, Nicholas L.; Hellard, Margaret; McBryde, Emma S.

    2015-01-01

    Vaccine effect, as measured in clinical trials, may not accurately reflect population-level impact. Furthermore, little is known about how sensitive apparent or real vaccine impacts are to factors such as the risk of re-infection or the mechanism of protection. We present a dynamic compartmental model to simulate vaccination for endemic infections. Several measures of effectiveness are calculated to compare the real and apparent impact of vaccination, and assess the effect of a range of infection and vaccine characteristics on these measures. Although broadly correlated, measures of real and apparent vaccine effectiveness can differ widely. Vaccine impact is markedly underestimated when primary infection provides partial natural immunity, when coverage is high and when post-vaccination infectiousness is reduced. Despite equivalent efficacy, ‘all or nothing’ vaccines are more effective than ‘leaky’ vaccines, particularly in settings with high risk of re-infection and transmissibility. Latent periods result in greater real impacts when risk of re-infection is high, but this effect diminishes if partial natural immunity is assumed. Assessments of population-level vaccine effects against endemic infections from clinical trials may be significantly biased, and vaccine and infection characteristics should be considered when modelling outcomes of vaccination programs, as their impact may be dramatic. PMID:26482413

  14. The stability of marker characteristics across tests of the same subject and across subjects.

    PubMed

    Lamprianou, Iasonas

    2006-01-01

    This research investigates the stability of marker characteristics within a very short period of time for both tests on the same subject as well as tests on different subjects. It reports on the scoring of the scripts of the whole cohort of students that took three high stakes tests in 2003 in a European country: a Language test consisting of a Literacy and a Literature paper and a History test. The many-facets Rasch model was used to study marker severity and marking consistency and it was found that some markers had more stable characteristics than others. Although the stability of marker characteristics was generally weak, it was non-negligible (correlation indices as indicators of stability ranged up to 0.707). This study, however, is not absolutely accurate due to the small sample sizes employed and it can be added that more research is needed to reach definite results.

  15. Ubiquitous testing using tablets: its impact on medical student perceptions of and engagement in learning

    PubMed Central

    Kim, Kyong-Jee; Hwang, Jee-Young

    2016-01-01

    Purpose: Ubiquitous testing has the potential to affect medical education by enhancing the authenticity of the assessment using multimedia items. This study explored medical students’ experience with ubiquitous testing and its impact on student learning. Methods: A cohort (n=48) of third-year students at a medical school in South Korea participated in this study. The students were divided into two groups and were given different versions of 10 content-matched items: one in text version (the text group) and the other in multimedia version (the multimedia group). Multimedia items were delivered using tablets. Item response analyses were performed to compare item characteristics between the two versions. Additionally, focus group interviews were held to investigate the students’ experiences of ubiquitous testing. Results: The mean test score was significantly higher in the text group. Item difficulty and discrimination did not differ between text and multimedia items. The participants generally showed positive responses on ubiquitous testing. Still, they felt that the lectures that they had taken in preclinical years did not prepare them enough for this type of assessment and clinical encounters during clerkships were more helpful. To be better prepared, the participants felt that they needed to engage more actively in learning in clinical clerkships and have more access to multimedia learning resources. Conclusion: Ubiquitous testing can positively affect student learning by reinforcing the importance of being able to understand and apply knowledge in clinical contexts, which drives students to engage more actively in learning in clinical settings. PMID:26838569

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    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.

  17. Predictive genetic testing for cardiovascular diseases: impact on carrier children.

    PubMed

    Meulenkamp, Tineke M; Tibben, Aad; Mollema, Eline D; van Langen, Irene M; Wiegman, Albert; de Wert, Guido M; de Beaufort, Inez D; Wilde, Arthur A M; Smets, Ellen M A

    2008-12-15

    We studied the experiences of children identified by family screening who were found to be a mutation carrier for a genetic cardiovascular disease (Long QT Syndrome (LQTS), Hypertrophic Cardiomyopathy (HCM), Familial Hypercholesterolemia (FH)). We addressed the (a) manner in which they perceive their carrier status, (b) impact on their daily lives, and (c) strategy used to cope with these consequences. Children (aged 8-18) who tested positive for LQTS (n=11), HCM (n=6) or FH (n=16), and their parents participated in semi-structured audiotaped interviews. Interview topics included illness perception, use of medication, lifestyle modifications, worries, and coping. Each interview was coded by two researchers. The qualitative analysis was guided by Leventhal's model of self-regulation. The children were overall quite articulate about the disease they were tested for, including its mode of inheritance. They expressed positive future health perceptions, but feelings of controllability varied. Adherence and side-effects were significant themes with regard to medication-use. Refraining from activities and maintaining a non-fat diet were themes concerning lifestyle modifications. Some children spontaneously reported worries about the possibility of dying and frustration about being different from peers. Children coped with these worries by expressing faith in the effectiveness of medication, trying to be similar to peers or, in contrast, emphasizing their "being different." Children generally appeared effective in the way they coped with their carrier status and its implications. Nevertheless, dealing with the daily implications of their condition remains difficult in some situations, warranting continued availability of psychosocial support.

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

    NASA Technical Reports Server (NTRS)

    1965-01-01

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

  19. Cyclic Material Properties Test to Determine Hardening/Softening Characteristics of HY-80 Steel

    SciTech Connect

    S.C. Hodge; J.M. Minicucci; T.F. Trimble

    2003-04-30

    The Cyclic Material Properties Test was structured to obtain and provide experimental data for determining cyclic hardening/softening characteristics of HY-80 steel. The inelastic strain history data generated by this test program and the resulting cyclic stress-strain curve will be used to enhance material models in the finite element codes used to perform nonlinear elastic-plastic analysis.

  20. Recent Trends in Characteristics of Graduate Management Admission Test Takers. GMAC Occasional Papers.

    ERIC Educational Resources Information Center

    Hudis, Paula M.; Stolzenberg, Ross M.

    Statistical trends in the characteristics of registrants for the Graduate Management Admission Test (GMAT) are presented. Areas of focus are: registrations (registration volumes have increased dramatically over time); worldwide age distribution (the percentage of older test registrants has increased); world distribution (there has been a…

  1. The effect of low velocity impact on the strength characteristics of composite materials laminates

    NASA Technical Reports Server (NTRS)

    Liebowitz, H.

    1986-01-01

    The nonlinear and dynamic response of composite structures to impact loading conditions was investigated. The convergence of both finite element and finite difference solution procedures was investigated with this configuration. The response of composite beams and plates to impact were examined. Fundamental data on the indentation and flexural response of both plate and beam geometry were collected. Numerical analyses were extended to the study of circular plates subjected to impact loading. Further work was done in modeling the response to simulated impact loading through careful modeling of the momentum transfer from impactor to target. The modeling methodology and solution procedures were well tested and verified. A computer program for the solution of circular plate problems was developed and is under testing.

  2. DEFORMATION CHARACTERISTICS OF CRUSHED-STONE LAYER UNDER CYCLIC IMPACT LOADING FROM MICRO-MECHANICAL VIEW

    NASA Astrophysics Data System (ADS)

    Kono, Akiko; Matsushima, Takashi

    'Hanging sleepers', which have gaps between sleepers and ballast layer are often found in the neighborhood of rail joints or rugged surface rails. This suggests that differential settlement of the ballast layer is due to impact loading generated by the contact between running wheel and rugged surface rail. Then cyclic loading tests were performed on crushed-stone layer with two loading patterns, the one is a cyclic impact loading and the other one is cyclic 'standard' loading controlled at 1/10 loading velocity of the impact loading. It was shown that the crashed-stone layer deforms with volumetric expansion during every off-loading processes under the cyclic impact loading. This phenomena prevents crushed stone layer from forming stable grain columns, then the residual settlement under the cyclic impact loading is larger than that under the cyclic 'standard' loading. A simple mass-spring model simulates that two masses move in the opposite direction with increased frequency of harmonic excitation.

  3. Impact characteristics of a vehicle population in low speed front to rear collisions.

    PubMed

    Nishimura, Naoya; Simms, Ciaran K; Wood, Denis P

    2015-06-01

    Rear impact collisions are mostly low severity, but carry a very high societal cost due to reported symptoms of whiplash and related soft tissue injuries. Given the difficulty in physiological measurement of damage in whiplash patients, there is a significant need to assess rear impact severity on the basis of vehicle damage. This paper presents fundamental impact equations on the basis of an equivalent single vehicle to rigid barrier collision in order to predict relationships between impact speed, maximum dynamic crush, mean and peak acceleration, time to common velocity and vehicle stiffness. These are then applied in regression analysis of published staged low speed rear impact tests. The equivalent mean and peak accelerations are linear functions of the collision closing speed, while the time to common velocity is independent of the collision closing speed. Furthermore, the time to common velocity can be used as a surrogate measure of the normalized vehicle stiffness, which provides opportunity for future accident reconstruction.

  4. Respiratory protection as a function of respirator fitting characteristics and fit-test accuracy.

    PubMed

    Campbell, D L; Coffey, C C; Lenhart, S W

    2001-01-01

    The fitting characteristics of particulate respirators are no longer assessed in the National Institute for Occupational Safety and Health respirator certification program. It is important for respirator program administrators to understand the implications of that change and the additional burden it may impose. To address that issue, a typical respirator fit-testing program is analyzed using a mathematical model that describes the effectiveness of a fit-testing program as a function of the fitting characteristics of the respirator and the accuracy of the fittesting method. The model is used to estimate (1) the respirator assignment error, the percentage of respirator wearers mistakenly assigned an ill-fitting respirator; (2) the number of fit-test trials necessary to qualify a group of workers for respirator use; and (3) the number of workers who will fail the fit-test with any candidate respirator model and thereby fail to qualify for respirator use. Using data from previous studies, the model predicts respirator assignment errors ranging from 0 to 20%, depending on the fitting characteristics of the respirator models selected and the fit-testing method used. This analysis indicates that when respirators do not necessarily have good fitting characteristics, respirator program administrators should exercise increased care in the selection of respirator models and increased care in fit-testing. Also presented are ways to assess the fitting characteristics of candidate respirator models by monitoring the first-time fit-testing results. The model demonstrates that significant public health and economic benefits can result when only respirators having good fitting characteristics are purchased and respirators are assigned to workers using highly accurate fit-testing methods.

  5. Effects of Fluid Load on Human Urine Characteristics Related to Workplace Drug testing

    DTIC Science & Technology

    2012-03-01

    Human Urine Characteristics Related to Workplace Drug Testing 7. Author(s) 8. Performing Organization Report No. Chaturvedi AK, 1 Sershon JL, 1 ...specimens from 12 males and 12 females were tested . These specimens were: 1 in the morning, 1 prior to drinking 800-mL of a beverage, and at 3 time...carbonated drink. Of the 480 samples collected, 376 were in sufficient amounts for validity testing . Of these 376 samples, 36 (10%) had creatinine

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

    ERIC Educational Resources Information Center

    Kearns, Laura-Lee

    2011-01-01

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

  7. Air quality resolution for health impact assessment: influence of regional characteristics

    NASA Astrophysics Data System (ADS)

    Thompson, T. M.; Saari, R. K.; Selin, N. E.

    2014-01-01

    We evaluate how regional characteristics of population and background pollution might impact the selection of optimal air quality model resolution when calculating the human health impacts of changes to air quality. Using an approach consistent with air quality policy evaluation, we use a regional chemical transport model (CAMx) and a health benefit mapping program (BenMAP) to calculate the human health impacts associated with changes in ozone and fine particulate matter resulting from an emission reduction scenario. We evaluate this same scenario at 36, 12 and 4 km resolution for nine regions in the eastern US representing varied characteristics. We find that the human health benefits associated with changes in ozone concentrations are sensitive to resolution. This finding is especially strong in urban areas where we estimate that benefits calculated using coarse resolution results are on average two times greater than benefits calculated using finer scale results. In three urban areas we analyzed, results calculated using 36 km resolution modeling fell outside the uncertainty range of results calculated using finer scale modeling. In rural areas the influence of resolution is less pronounced with only an 8% increase in the estimated health impacts when using 36 km resolution over finer scales. In contrast, health benefits associated with changes in PM2.5 concentrations were not sensitive to resolution and did not follow a pattern based on any regional characteristics evaluated. The largest difference between the health impacts estimated using 36 km modeling results and either 12 or 4 km results was at most ±10% in any region. Several regions showed increases in estimated benefits as resolution increased (opposite the impact seen with ozone modeling), while some regions showed decreases in estimated benefits as resolution increased. In both cases, the dominant contribution was from secondary PM. Additionally, we found that the health impacts calculated using

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

    NASA Technical Reports Server (NTRS)

    Nettles, A. T.

    1990-01-01

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

  9. Design and testing of miniaturized plasma sensor for measuring hypervelocity impact plasmas.

    PubMed

    Goel, A; Tarantino, P M; Lauben, D S; Close, S

    2015-04-01

    An increasingly notable component of the space environment pertains to the impact of meteoroids and orbital debris on spacecraft and the resulting mechanical and electrical damages. Traveling at speeds of tens of km/s, when these particles, collectively referred to as hypervelocity particles, impact a satellite, they vaporize, ionize, and produce a radially expanding plasma that can generate electrically harmful radio frequency emission or serve as a trigger for electrostatic discharge. In order to measure the flux, composition, energy distribution, and temperature of ions and electrons in this plasma, a miniaturized plasma sensor has been developed for carrying out in-situ measurements in space. The sensor comprises an array of electrostatic analyzer wells split into 16 different channels, catering to different species and energy ranges in the plasma. We present results from numerical simulation based optimization of sensor geometry. A novel approach of fabricating the sensor using printed circuit boards is implemented. We also describe the test setup used for calibrating the sensor and show results demonstrating the energy band pass characteristics of the sensor. In addition to the hypervelocity impact plasmas, the plasma sensor developed can also be used to carry out measurements of ionospheric plasma, diagnostics of plasma propulsion systems, and in other space physics experiments.

  10. Design and testing of miniaturized plasma sensor for measuring hypervelocity impact plasmas

    SciTech Connect

    Goel, A. Tarantino, P. M.; Lauben, D. S.; Close, S.

    2015-04-15

    An increasingly notable component of the space environment pertains to the impact of meteoroids and orbital debris on spacecraft and the resulting mechanical and electrical damages. Traveling at speeds of tens of km/s, when these particles, collectively referred to as hypervelocity particles, impact a satellite, they vaporize, ionize, and produce a radially expanding plasma that can generate electrically harmful radio frequency emission or serve as a trigger for electrostatic discharge. In order to measure the flux, composition, energy distribution, and temperature of ions and electrons in this plasma, a miniaturized plasma sensor has been developed for carrying out in-situ measurements in space. The sensor comprises an array of electrostatic analyzer wells split into 16 different channels, catering to different species and energy ranges in the plasma. We present results from numerical simulation based optimization of sensor geometry. A novel approach of fabricating the sensor using printed circuit boards is implemented. We also describe the test setup used for calibrating the sensor and show results demonstrating the energy band pass characteristics of the sensor. In addition to the hypervelocity impact plasmas, the plasma sensor developed can also be used to carry out measurements of ionospheric plasma, diagnostics of plasma propulsion systems, and in other space physics experiments.

  11. Design and testing of miniaturized plasma sensor for measuring hypervelocity impact plasmas

    NASA Astrophysics Data System (ADS)

    Goel, A.; Tarantino, P. M.; Lauben, D. S.; Close, S.

    2015-04-01

    An increasingly notable component of the space environment pertains to the impact of meteoroids and orbital debris on spacecraft and the resulting mechanical and electrical damages. Traveling at speeds of tens of km/s, when these particles, collectively referred to as hypervelocity particles, impact a satellite, they vaporize, ionize, and produce a radially expanding plasma that can generate electrically harmful radio frequency emission or serve as a trigger for electrostatic discharge. In order to measure the flux, composition, energy distribution, and temperature of ions and electrons in this plasma, a miniaturized plasma sensor has been developed for carrying out in-situ measurements in space. The sensor comprises an array of electrostatic analyzer wells split into 16 different channels, catering to different species and energy ranges in the plasma. We present results from numerical simulation based optimization of sensor geometry. A novel approach of fabricating the sensor using printed circuit boards is implemented. We also describe the test setup used for calibrating the sensor and show results demonstrating the energy band pass characteristics of the sensor. In addition to the hypervelocity impact plasmas, the plasma sensor developed can also be used to carry out measurements of ionospheric plasma, diagnostics of plasma propulsion systems, and in other space physics experiments.

  12. HIV testing among MSM in Bogotá, Colombia: The role of structural and individual characteristics

    PubMed Central

    Reisen, Carol A.; Zea, Maria Cecilia; Bianchi, Fernanda T.; Poppen, Paul J.; del Río González, Ana Maria; Romero, Rodrigo A. Aguayo; Pérez, Carolin

    2014-01-01

    This study used mixed methods to examine characteristics related to HIV testing among men who have sex with men (MSM) in Bogotá, Colombia. A sample of 890 MSM responded to a computerized quantitative survey. Follow-up qualitative data included 20 in-depth interviews with MSM and 12 key informant interviews. Hierarchical logistic set regression indicated that sequential sets of variables reflecting demographic characteristics, insurance coverage, risk appraisal, and social context each added to the explanation of HIV testing. Follow-up logistic regression showed that individuals who were older, had higher income, paid for their own insurance, had had a sexually transmitted infection, knew more people living with HIV, and had greater social support were more likely to have been tested for HIV at least once. Qualitative findings provided details of personal and structural barriers to testing, as well as interrelationships among these factors. Recommendations to increase HIV testing among Colombian MSM are offered. PMID:25068180

  13. Damage Characteristics of the Logical Chip Module Due to Plasma Created by Hypervelocity Impacts

    NASA Astrophysics Data System (ADS)

    Tang, Enling; Wu, Jin; Wang, Meng; Zhang, Lijiao; Xiang, Shenghai; Xia, Jin; Liu, Shuhua; He, Liping; Han, Yafei; Xu, Mingyang; Zhang, Shuang; Yuan, Jianfei

    2016-04-01

    To researching the damage characteristics of typical logical chip modules in spacecraft due to plasma generated by hypervelocity impacts, we have established a triple Langmuir probe diagnostic system and a logical chips measurement system, which were used to diagnose plasma characteristic parameters and the logical chip module's logical state changes due to the plasma created by a 7075 aluminum projectile hypervelocity impact on the 2A12 aluminum target. Three sets of experiments were performed with the collision speeds of 2.85 km/s, 3.1 km/s and 2.20 km/s, at the same incident angles of 30 degrees and logical chip module's positions by using a two-stage light gas gun loading system, a plasma characteristic parameters diagnostic system and a logical chip module's logical state measurement system, respectively. Electron temperature and density were measured at given position and azimuth, and damage estimation was performed for the logical chip module by using the data acquisition system. Experimental results showed that temporary damage could be induced on logical chip modules in spacecraft by plasma generated by hypervelocity impacts under the given experimental conditions and the sensors' position and azimuth. supported by National Natural Science Foundation of China (Nos. 10972145, 11272218, 11472178), Program for Liaoning Excellent Talents in University of China (No. LR2013008), Open Foundation of Key Laboratory of Liaoning Weapon Science and Technology, Liaoning Province Talents Engineering Projects of China (No. 2012921044)

  14. Human impact on the Middle and Late Holocene floodplain sediment characteristics along the River Rhine

    NASA Astrophysics Data System (ADS)

    Erkens, G.; Prins, M.; Toonen, W.

    2012-04-01

    The Rhine catchment has an extensive history of human land use. Deforestation to create arable land started as early as 6300 cal BP, at the onset of the Late Neolithic. This caused increased erosion and sediment production on the hillslopes in the upstream part of the fluvial system. Recent studies show that this human-induced erosion also increased the suspended load sedimentation rates in the Rhine trunk valley and delta from approximately 3000 years ago. Besides such changes in the quantity of fine sediment, it is hypothesised that human land use may also change the source of the sediment supplied to the fluvial system. Sediment released by erosion during agricultural practises may be different than the sediments that erode under conditions of forest cover. If this is true, the Late Holocene floodplain sediments have different characteristics in terms of grain size and texture than older floodplain deposits (Middle Holocene). To test this, we collected 15 cores from three large stretches along the trunk Rhine River: the Upper Rhine Graben, the Lower Rhine Valley, and the Rhine Delta. Using detailed palaeogeographic reconstructions of the area, the cores were carefully selected in order to (i) to obtain the longest possible record (preferably up to 5000 years), and (ii) to have a continuous sedimentation record as much as possible. Cores are taken from residual channels, and distal flood basin and plains, although very distal sites were avoided to minimise the amount of peat or soil formation. Individual age-depth models are derived from radiocarbon dates taken in the cores, correlation of the regional deposits with a known age, and by using groundwater models (in the delta). Grain size characteristics of the siliciclastic sediment fraction were analysed every 2-5 cm, which yielded a record of grain size variations of the floodplains depositions in time. Using the end-member modelling algorithm EMMA it was possible to distinguish different groups of sediment

  15. The impact of green roof ageing on substrate characteristics and hydrological performance

    NASA Astrophysics Data System (ADS)

    De-Ville, Simon; Menon, Manoj; Jia, Xiaodong; Reed, George; Stovin, Virginia

    2017-04-01

    Green roofs contribute to stormwater management through the retention of rainfall and the detention of runoff. However, there is very limited knowledge concerning the evolution of green roof hydrological performance with system age. This study presents a non-invasive technique which allows for repeatable determination of key substrate characteristics over time, and evaluates the impact of observed substrate changes on hydrological performance. The physical properties of 12 green roof substrate cores have been evaluated using non-invasive X-ray microtomography (XMT) imaging. The cores comprised three replicates of two contrasting substrate types at two different ages: unused virgin samples; and 5-year-old samples from existing green roof test beds. Whilst significant structural differences (density, pore and particle sizes, tortuosity) between virgin and aged samples of a crushed brick substrate were observed, these differences did not significantly affect hydrological characteristics (maximum water holding capacity and saturated hydraulic conductivity). A contrasting substrate based upon a light expanded clay aggregate experienced increases in the number of fine particles and pores over time, which led to increases in maximum water holding capacity of 7%. In both substrates, the saturated hydraulic conductivity estimated from the XMT images was lower in aged compared with virgin samples. Comparisons between physically-derived and XMT-derived substrate hydrological properties showed that similar values and trends in the data were identified, confirming the suitability of the non-invasive XMT technique for monitoring changes in engineered substrates over time. The observed effects of ageing on hydrological performance were modelled as two distinct hydrological processes, retention and detention. Retention performance was determined via a moisture-flux model using physically-derived values of virgin and aged maximum water holding capacity. Increased water holding

  16. [Impacts of the hydraulic characteristics of pilot clearwell on chlorine disinfection efficiency].

    PubMed

    Liu, Qing; Liu, Wen-Jun; Gao, Jing-Wei; Zhang, Su-Xia

    2009-09-15

    A pilot clearwell was used to simulate the chlorine disinfection process with the Bacillus subtilis spores as the target microbe. The effluent of the activated carbon filter tank was radiated by low pressure UV lamp and then used as the influent the pilot clearwell. The impacts of hydraulic characteristics of pilot clearwell on disinfection efficiency of Bacillus subtilis spores was studied under different hydraulic characteristics which was changed by the number of the baffles. Under the conditions of this experiment, the inactivation coefficients of Bacillus subtilis spores with NaC10 as disinfectant which were calculated by Ct10 value were almost same under different hydraulic characteristics, but the inactivation coefficients which were calculated by CT value were very different under different hydraulic characteristics. This verified that it was more reasonable to evaluate the disinfection efficiency by Ct10 value than CT value. When Ct10 value was in the range of 100 - 300 mg x min/L, the inactivation coefficient of Bacillus subtilis spores with NaClO as disinfectant was 0.001 6 L(mg x min), which highly coincided with others' results. When CT value was in the range of 100 - 700 mg x min/L, under the same CT value, the disinfection efficiency of target microbe would be notably enhanced by increasing the number of baffles which would improve the hydraulic characteristics. So the results verified that the disinfection efficiency could be enhanced by improving the hydraulic characteristics of the clearwell.

  17. Numerical and experimental investigations of splat geometric characteristics during oblique impact of plasma spraying

    NASA Astrophysics Data System (ADS)

    Kang, Chang-Wei; Tan, Jiak Kwang; Pan, Lunsheng; Low, Cheng Yee; Jaffar, Ahmed

    2011-10-01

    Splats are obtained on the substrates inclined at different angles (0°, 20°, 40° and 60°) by plasma spraying process and characterized by SEM and WYKO ® optical surface profiler. Numerical model is developed using CFD software FLOW-3D ® to simulate the process of droplet impact, spreading and solidification onto the substrates. Splat characteristics such as spread factor, aspect ratio and fractional factor are defined and compared between simulation and experiment. Fair agreements are obtained. In addition, the impacting behavior including spreading and solidification are analyzed in details from the simulation results. The rates of reduction in droplet kinetic energy during impact, spreading and solidification are also compared between different inclination angles.

  18. Study on electromagnetic radiation and mechanical characteristics of coal during an SHPB test

    NASA Astrophysics Data System (ADS)

    Chengwu, Li; Qifei, Wang; Pingyang, Lyu

    2016-06-01

    Dynamic loads provided by a Split Hopkinson pressure bar are applied in the impact failure experiment on coal with an impact velocity of 4.174-17.652 m s-1. The mechanical property characteristics of coal and an electromagnetic radiation signal can be detected and measured during the experiment. The variation of coal stress, strain, incident energy, dissipated energy and other mechanical parameters are analyzed by the unidimensional stress wave theory. It suggests that with an increase of the impact velocity, the mechanical parameters and electromagnetic radiation increased significantly and the dissipated energy of the coal sample has a high discrete growing trend during the failure process of coal impact. Combined with the received energy of the electromagnetic radiation signal, the relationship between these mechanical parameters and electromagnetic radiation during the failure process of coal burst could be analyzed by the grey correlation model. The results show that the descending order of the gray correlation degree between the mechanical characteristics and electromagnetic radiation energy are impact velocity, maximum stress, the average stress, incident energy, the average strain, maximum strain, the average strain rate and dissipation energy. Due to the correlation degree, the impact velocity and incident energy are relatively large, and the main factor affecting the electromagnetic radiation energy of coal is the energy magnitude. While the relationship between extreme stress and the radiation energy change trend is closed, the stress state of coal has a greater impact on electromagnetic radiation than the strain and destruction which can deepen the research of the coal-rock dynamic disaster electromagnetic monitoring technique.

  19. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... percent for at least four hours prior to a test. (2) Mount the test material and secure it to a rigid test... 49 Transportation 7 2014-10-01 2014-10-01 false Knees and knee impact test procedure. 572.126... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES...

  20. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... percent for at least four hours prior to a test. (2) Mount the test material and secure it to a rigid test... 49 Transportation 7 2013-10-01 2013-10-01 false Knees and knee impact test procedure. 572.126... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES...

  1. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... percent for at least four hours prior to a test. (2) Mount the test material and secure it to a rigid test... 49 Transportation 7 2012-10-01 2012-10-01 false Knees and knee impact test procedure. 572.126... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES...

  2. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... percent for at least four hours prior to a test. (2) Mount the test material and secure it to a rigid test... 49 Transportation 7 2010-10-01 2010-10-01 false Knees and knee impact test procedure. 572.126... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES...

  3. 49 CFR 572.126 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... percent for at least four hours prior to a test. (2) Mount the test material and secure it to a rigid test... 49 Transportation 7 2011-10-01 2011-10-01 false Knees and knee impact test procedure. 572.126... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST DEVICES...

  4. A statistical comparison of impact and ambient testing results from the Alamosa Canyon Bridge

    SciTech Connect

    Doebling, S.W.; Farrar, C.R.; Cornwell, P.

    1996-12-31

    In this paper, the modal properties of the Alamosa Canyon Bridge obtained using ambient data are compared to those obtained from impact hammer vibration tests. Using ambient sources of excitation to determine the modal characteristics of large civil engineering structures is desirable for several reasons. The forced vibration testing of such structures generally requires a large amount of specialized equipment and trained personnel making the tests quite expensive. Also, an automated health monitoring system for a large civil structure will most likely use ambient excitation. A modal identification procedure based on a statistical Monte Carlo analysis using the Eigensystem Realization Algorithm is used to compute the modal parameters and their statistics. The results show that for most of the measured modes, the differences between the modal frequencies of the ambient and hammer data sets are statistically significant. However, the differences between the corresponding damping ratio results are not statistically significant. Also, one of the modes identified from the hammer test data was not identifiable from the ambient data set.

  5. Hypervelocity Impact Testing of Space Station Freedom Solar Cells

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

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

    ERIC Educational Resources Information Center

    Baker, Melissa; Johnston, Pattie

    2010-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  8. Characteristics, finite element analysis, test description, and preliminary test results of the STM4-120 kinematic Stirling engine

    SciTech Connect

    Linker, K.L.; Rawlinson, K.S.; Smith, G.

    1991-10-01

    The Department of Energy's Solar Thermal Program has as one of its program elements the development and evaluation of conversion device technologies applicable to dish-electric systems. The primary research and development combines a conversion device (heat engine), solar receiver, and generator mounted at the focus of a parabolic dish concentrator. The Stirling-cycle heat engine was identified as the conversion device for dish-electric with the most potential for meeting the program's goals for efficiency, reliability, and installed cost. To advance the technology toward commercialization, Sandia National Laboratories has acquired a Stirling Thermal Motors, Inc., kinematic Stirling engine, STM4-120, for evaluation. The engine is being bench-tested at Sandia's Engine Test Facility and will be combined later with a solar receiver for on-sun evaluation. This report presents the engine characteristics, finite element analyses of critical engine components, test system layout, instrumentation, and preliminary performance results from the bench test.

  9. The mineralogical, chemical, and chronological characteristics of the crystalline Apollo 16 impact melt rocks

    NASA Technical Reports Server (NTRS)

    Reimold, W. U.; Reimold, J. N.

    1984-01-01

    A comparative review of mineralogical, chemical, and chronological data on crystalline Apollo 16 impact melt rocks is presented. The use of such data to identify distinct impact melt complex is discussed, and 22 distinct impact melt bodies are identified. The recently detected group of feldspathic microporphyritic (FM) melt rocks was tested for chemical and isotopic homogeneity; instrumental neutron activation analysis and new Rb-Sr isotopic whole rock data indicate that FMs were probably not derived from a single impact melt sheet, but might be representative of the Descartes basement. Stratigraphical and chronological concepts for the geological development of the landing site are discussed, and a model is presented for the formation of the Cayley Plains and the Descartes formation.

  10. Variability in clubhead presentation characteristics and ball impact location for golfers' drives.

    PubMed

    Betzler, Nils F; Monk, Stuart A; Wallace, Eric S; Otto, Steve R

    2012-01-01

    The purpose of the present study was to analyse the variability in clubhead presentation to the ball and the resulting ball impact location on the club face for a range of golfers of different ability. A total of 285 male and female participants hit multiple shots using one of four proprietary drivers. Self-reported handicap was used to quantify a participant's golfing ability. A bespoke motion capture system and user-written algorithms was used to track the clubhead just before and at impact, measuring clubhead speed, clubhead orientation, and impact location. A Doppler radar was used to measure golf ball speed. Generally, golfers of higher skill (lower handicap) generated increased clubhead speed and increased efficiency (ratio of ball speed to clubhead speed). Non-parametric statistical tests showed that low-handicap golfers exhibit significantly lower variability from shot to shot in clubhead speed, efficiency, impact location, attack angle, club path, and face angle compared with high-handicap golfers.

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

    NASA Technical Reports Server (NTRS)

    Probst, H B; Mchenry, Howard T

    1957-01-01

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

  12. Air quality resolution for health impacts assessment: influence of regional characteristics

    NASA Astrophysics Data System (ADS)

    Thompson, T. M.; Saari, R. K.; Selin, N. E.

    2013-05-01

    We evaluate how regional characteristics of weather, population, and background pollution might impact the selection of optimal model resolution when calculating the human health impacts of changes to air quality. Using an approach consistent with air quality policy evaluation, we use a regional chemical transport model (CAMx) and a health benefits mapping program (BenMAP) to calculate the human health impacts associated with changes in ozone and fine particulate matter resulting from an emissions reduction scenario. We evaluate this same scenario at 36, 12 and 4 km resolution for nine regions in the Eastern US representing varied characteristics. We find that the human health benefits associated with changes in ozone concentrations are sensitive to resolution, especially in urban areas where we estimate that benefits calculated using coarse resolution results are on average two times greater than benefits calculated using finer scale results. In three urban areas we analyzed, results calculated using 36 km resolution modeling fell outside the uncertainty range of results calculated using finer scale modeling. In rural areas the influence of resolution is less pronounced with only an 8% increase in the estimated health impacts when using 36 km resolution over finer scales. In contrast, health benefits associated with changes in PM2.5 concentrations were not sensitive to resolution and did not follow a pattern based on any regional characteristics evaluated. The largest difference between the health impacts estimated using 36 km modeling results and either 12 or 4 km results was at most ±10% in any region. Several regions showed increases in estimated benefits as resolution increased (opposite the impact seen with ozone modeling) due to a higher contribution of primary PM in those regions, while some regions showed decreases in estimated benefits as resolution increased due to a higher contribution of secondary PM. Given that changes in PM2.5 dominate the human

  13. An investigation of the NOCSAE linear impactor test method based on in vivo measures of head impact acceleration in American football.

    PubMed

    Gwin, Joseph T; Chu, Jeffery J; Diamond, Solomon G; Halstead, P David; Crisco, Joseph J; Greenwald, Richard M

    2010-01-01

    The performance characteristics of football helmets are currently evaluated by simulating head impacts in the laboratory using a linear drop test method. To encourage development of helmets designed to protect against concussion, the National Operating Committee for Standards in Athletic Equipment recently proposed a new headgear testing methodology with the goal of more closely simulating in vivo head impacts. This proposed test methodology involves an impactor striking a helmeted headform, which is attached to a nonrigid neck. The purpose of the present study was to compare headform accelerations recorded according to the current (n=30) and proposed (n=54) laboratory test methodologies to head accelerations recorded in the field during play. In-helmet systems of six single-axis accelerometers were worn by the Dartmouth College men's football team during the 2005 and 2006 seasons (n=20,733 impacts; 40 players). The impulse response characteristics of a subset of laboratory test impacts (n=27) were compared with the impulse response characteristics of a matched sample of in vivo head accelerations (n=24). Second- and third-order underdamped, conventional, continuous-time process models were developed for each impact. These models were used to characterize the linear head/headform accelerations for each impact based on frequency domain parameters. Headform linear accelerations generated according to the proposed test method were less similar to in vivo head accelerations than headform accelerations generated by the current linear drop test method. The nonrigid neck currently utilized was not developed to simulate sport-related direct head impacts and appears to be a source of the discrepancy between frequency characteristics of in vivo and laboratory head/headform accelerations. In vivo impacts occurred 37% more frequently on helmet regions, which are tested in the proposed standard than on helmet regions tested currently. This increase was largely due to the

  14. Experimental and numerical analysis of Al6063 duralumin using Taylor impact test

    NASA Astrophysics Data System (ADS)

    Kruszka, L.; Anaszewicz, Ł.; Janiszewski, J.; Grązka, M.

    2012-08-01

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

  15. Impact of the introduction of rapid HIV testing in the Voluntary Counselling and Testing sites network of Catalonia, Spain.

    PubMed

    Fernàndez-Lopez, L; Rifà, B; Pujol, F; Becerra, J; Pérez, M; Meroño, M; Zaragoza, K; Rafel, A; Díaz, O; Avellaneda, A; Casado, M J; Giménez, A; Casabona, J

    2010-06-01

    Rapid HIV antibody tests, which provide results within 15-60 minutes, can help reduce the number of unrecognized infections by improving access to testing facilities and increase the number of people tested who know their results. After an acceptability study, rapid HIV testing was first implemented in Catalonia in 2007 within the community-based Voluntary Counselling and Testing sites network. One year after implementation, an increase of 102.9% has been observed in the number of tests performed, ranging from 8.4% to 328.3% according to the site. Despite the important immediate impact of rapid HIV testing on the number of tests performed, there was no significant change in the proportion of tests that were positive. Rapid HIV testing can help increase access to testing, but it should be complemented with specific outreach programmes targeting the most vulnerable subgroups.

  16. Tests for Determining Failure Criteria of Ceramics under Ballistic Impact

    DTIC Science & Technology

    1992-06-01

    conclude that pressure/shear tests in these two configurations with rear surface laser diagnostics and with appropriate constitutive analysis are...Shear Test 18 Hxperimental Technique 18 Analysis Techniques 23 Results 25 Pressure/Shear Tests 25 Analyses 30 Discussion 39 4 OTHER...TDI cannot. Analysis Techniques The extraction of stresses, strains, and other mechanical variables from the transverse velocity history recorded

  17. Impact of land cover change on the environmental hydrology characteristics in Kelantan river basin, Malaysia

    NASA Astrophysics Data System (ADS)

    Saadatkhah, Nader; Mansor, Shattri; Khuzaimah, Zailani; Asmat, Arnis; Adnan, Noraizam; Adam, Siti Noradzah

    2016-09-01

    Changing the land cover/ land use has serious environmental impacts affecting the ecosystem in Malaysia. The impact of land cover changes on the environmental functions such as surface water, loss water, and soil moisture is considered in this paper on the Kelantan river basin. The study area at the east coast of the peninsular Malaysia has suffered significant land cover changes in the recent years. The current research tried to assess the impact of land cover changes in the study area focused on the surface water, loss water, and soil moisture from different land use classes and the potential impact of land cover changes on the ecosystem of Kelantan river basin. To simulate the impact of land cover changes on the environmental hydrology characteristics, a deterministic regional modeling were employed in this study based on five approaches, i.e. (1) Land cover classification based on Landsat images; (2) assessment of land cover changes during last three decades; (3) Calculation the rate of water Loss/ Infiltration; (4) Assessment of hydrological and mechanical effects of the land cover changes on the surface water; and (5) evaluation the impact of land cover changes on the ecosystem of the study area. Assessment of land cover impact on the environmental hydrology was computed with the improved transient rainfall infiltration and grid based regional model (Improved-TRIGRS) based on the transient infiltration, and subsequently changes in the surface water, due to precipitation events. The results showed the direct increased in surface water from development area, agricultural area, and grassland regions compared with surface water from other land covered areas in the study area. The urban areas or lower planting density areas tend to increase for surface water during the monsoon seasons, whereas the inter flow from forested and secondary jungle areas contributes to the normal surface water.

  18. Scale Effect on Clark Y Airfoil Characteristics from NACA Full-Scale Wind-Tunnel Tests

    NASA Technical Reports Server (NTRS)

    Silverstein, Abe

    1935-01-01

    This report presents the results of wind tunnel tests conducted to determine the aerodynamic characteristics of the Clark Y airfoil over a large range of Reynolds numbers. Three airfoils of aspect ratio 6 and with 4, 6, and 8 foot chords were tested at velocities between 25 and 118 miles per hour, and the characteristics were obtained for Reynolds numbers (based on the airfoil chord) in the range between 1,000,000 and 9,000,000 at the low angles of attack, and between 1,000,000 and 6,000,000 at maximum lift. With increasing Reynolds number the airfoil characteristics are affected in the following manner: the drag at zero lift decreases, the maximum lift increases, the slope of the lift curve increases, the angle of zero lift occurs at smaller negative angles, and the pitching moment at zero lift does not change appreciably.

  19. Testing Measurement Invariance of the Students' Affective Characteristics Model across Gender Sub-Groups

    ERIC Educational Resources Information Center

    Demir, Ergül

    2017-01-01

    In this study, the aim was to construct a significant structural measurement model comparing students' affective characteristics with their mathematic achievement. According to this model, the aim was to test the measurement invariances between gender sub-groups hierarchically. This study was conducted as basic and descriptive research. Secondary…

  20. 30 CFR 250.407 - What tests must I conduct to determine reservoir characteristics?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations General Requirements § 250.407 What tests must I conduct to... characteristics of oil, gas, sulphur, and water in the formations penetrated by logging, formation sampling,...

  1. 30 CFR 250.407 - What tests must I conduct to determine reservoir characteristics?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations General Requirements § 250.407 What tests must I conduct to... characteristics of oil, gas, sulphur, and water in the formations penetrated by logging, formation sampling,...

  2. 30 CFR 250.407 - What tests must I conduct to determine reservoir characteristics?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations General Requirements § 250.407 What tests must I conduct to... characteristics of oil, gas, sulphur, and water in the formations penetrated by logging, formation sampling,...

  3. The Monosyllable Imitation Test for Toddlers: Influence of Stimulus Characteristics on Imitation, Compliance and Diagnostic Accuracy

    ERIC Educational Resources Information Center

    Hodges, Rosemary; Munro, Natalie; Baker, Elise; McGregor, Karla; Heard, Rob

    2017-01-01

    Background: Although verbal imitation can provide a valuable window into the developing language abilities of toddlers, some toddlers find verbal imitation challenging and will not comply with tests that involve elicited verbal imitation. The characteristics of stimuli that are offered to toddlers for imitation may influence how easy or hard it is…

  4. Disruptiveness, Friends' Characteristics, and Delinquency in Early Adolescence: A Test of Two Competing Models of Development.

    ERIC Educational Resources Information Center

    Vitaro, Frank; Tremblay, Richard E.; Kerr, Margaret; Pagani, Linda; Bukowski, William M.

    1997-01-01

    Tested the individual characteristics and deviant peer association theoretical models of friends' influence on the development of delinquency in disruptive boys. Found that moderately disruptive boys with aggressive-disturbing friends were more delinquent at age 13 than other subgroups of moderately disruptive boys. Highly disruptive and…

  5. 30 CFR 250.407 - What tests must I conduct to determine reservoir characteristics?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... reservoir characteristics? 250.407 Section 250.407 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations General Requirements § 250.407 What tests must...

  6. Impact characteristics of female children running in adult versus youth shoes of the same size.

    PubMed

    Forrest, Dana; Dufek, Janet S; Mercer, John A

    2012-11-01

    The purpose of this study was to determine if ground reaction forces were influenced by shoe design (adult vs. youth) for female children when running. Subjects (n = 10, 12.0 ± 1.1 years old; 154 ± 4.9 cm; 46.2 ± 14.3 kg; shoe size 3.5-7 youth) were fit with a shoe model available in youth and adult sizes. Subjects ran 10 trials per shoe condition across a force platform placed in the middle of a 9-m runway. Impact force, second maximum force, loading rate, stance time and average vertical ground reaction forces were recorded for each trial. Shoes underwent a mechanical impact test with peak force, peak acceleration, and percent energy returned recorded. Each variable was compared between shoe conditions. From the impact testing, it was determined that peak force, peak acceleration and percent energy return were 7.1%, 7.1%, and 18.9% greater, respectively, for the youth vs. adult shoe (p < .001). From the running tests, it was determined that loading rate was different (p = .009) between shoe conditions whereas impact force, second maximum force, average force and stance time were not different between shoes (p > .01). Young girls had a greater loading rate when running in youth vs. adult shoes even though the shoe size was the same.

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

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  8. Soft Soil Impact Testing and Simulation of Aerospace Structures

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

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

    SciTech Connect

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

    1981-10-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  11. Market Impact and Order Book Characteristics in the Korean Futures Market

    NASA Astrophysics Data System (ADS)

    Lee, Junghoon; Youn, Janghyuk; Chang, Woojin

    We have examined the order book characteristics and market impact on the Korean stock index futures market (KOSPI 200 index futures). The distribution of order volumes generally follows power-law distribution. The estimated exponents are 1.9 for market order, 2.5 for limit order, and 2.1 for cancel order. This result is different from the case of stocks where the exponent of market order is larger than that of limit order. The order likelihood is distinctively high in every 50's of order volume, which implies the behavioral characteristics of human preference on round-up numbers. The distributions of bid-ask spread and the best quotes volume provide the evidence of the liquidity of KOSPI 200 index futures market. We have obtained the concave relationship between market impact and transaction volume as well. Finally, the market response behavior is observed regarding various transaction sizes. The size of market response is estimated to be proportional to the size of transaction. Also, the larger the transaction size is, the longer it takes to recover the stability from the impact triggered by transaction.

  12. The impact of cold spells on mortality and effect modification by cold spell characteristics

    NASA Astrophysics Data System (ADS)

    Wang, Lijun; Liu, Tao; Hu, Mengjue; Zeng, Weilin; Zhang, Yonghui; Rutherford, Shannon; Lin, Hualiang; Xiao, Jianpeng; Yin, Peng; Liu, Jiangmei; Chu, Cordia; Tong, Shilu; Ma, Wenjun; Zhou, Maigeng

    2016-12-01

    In China, the health impact of cold weather has received little attention, which limits our understanding of the health impacts of climate change. We collected daily mortality and meteorological data in 66 communities across China from 2006 to 2011. Within each community, we estimated the effect of cold spell exposure on mortality using a Distributed Lag Nonlinear Model (DLNM). We also examined the modification effect of cold spell characteristics (intensity, duration, and timing) and individual-specific factors (causes of death, age, gender and education). Meta-analysis method was finally used to estimate the overall effects. The overall cumulative excess risk (CER) of non-accidental mortality during cold spell days was 28.2% (95% CI: 21.4%, 35.3%) compared with non-cold spell days. There was a significant increase in mortality when the cold spell duration and intensity increased or occurred earlier in the season. Cold spell effects and effect modification by cold spell characteristics were more pronounced in south China. The elderly, people with low education level and those with respiratory diseases were generally more vulnerable to cold spells. Cold spells statistically significantly increase mortality risk in China, with greater effects in southern China. This effect is modified by cold spell characteristics and individual-level factors.

  13. The impact of cold spells on mortality and effect modification by cold spell characteristics

    PubMed Central

    Wang, Lijun; Liu, Tao; Hu, Mengjue; Zeng, Weilin; Zhang, Yonghui; Rutherford, Shannon; Lin, Hualiang; Xiao, Jianpeng; Yin, Peng; Liu, Jiangmei; Chu, Cordia; Tong, Shilu; Ma, Wenjun; Zhou, Maigeng

    2016-01-01

    In China, the health impact of cold weather has received little attention, which limits our understanding of the health impacts of climate change. We collected daily mortality and meteorological data in 66 communities across China from 2006 to 2011. Within each community, we estimated the effect of cold spell exposure on mortality using a Distributed Lag Nonlinear Model (DLNM). We also examined the modification effect of cold spell characteristics (intensity, duration, and timing) and individual-specific factors (causes of death, age, gender and education). Meta-analysis method was finally used to estimate the overall effects. The overall cumulative excess risk (CER) of non-accidental mortality during cold spell days was 28.2% (95% CI: 21.4%, 35.3%) compared with non-cold spell days. There was a significant increase in mortality when the cold spell duration and intensity increased or occurred earlier in the season. Cold spell effects and effect modification by cold spell characteristics were more pronounced in south China. The elderly, people with low education level and those with respiratory diseases were generally more vulnerable to cold spells. Cold spells statistically significantly increase mortality risk in China, with greater effects in southern China. This effect is modified by cold spell characteristics and individual-level factors. PMID:27922084

  14. Impact of Wettability on Pore-Scale Characteristics of Residual Nonaqueous Phase Liquids

    SciTech Connect

    Al-Raoush, Riyadh I.

    2009-07-31

    The objective of this paper was to investigate the impact of wettability of porous media on pore-scale characteristics of residual nonaqueous phase liquids (NAPLs). Synchrotron X-ray microtomography was used to obtain high-resolution three-dimensional images of fractionally wet sand systems with mean grain size of 250 {micro}m. Pore-scale characteristics of NAPL blobs such as volume, lengths, interfacial areas, and sphericity index were computed using three-dimensional image processing algorithms. Four systems comprised of 100, 50, 25, and 0% NAPL-wet mass fractions containing the residual NAPL were imaged and analyzed. Findings indicate that spatial variation in wettability of porous media surfaces has a significant impact on pore-scale characteristics of residual NAPL blobs in saturated porous media systems. As the porous media comprises more water-wet surfaces, residual NAPL blobs increase in size and length due to the entrapment at large pore bodies. NAPL-water interfacial areas tend to increase as the NAPL-wet surface fractions increase in the systems. Overall residual NAPL saturations are less in fractionally wet systems and increase as the systems become more NAPL-wet or water-wet.

  15. 16 CFR Figure 1 to Subpart A of... - Glass Impact Test Structure

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Glass Impact Test Structure 1 Figure 1 to Subpart A of Part 1201 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT... 1 to Subpart A of Part 1201—Glass Impact Test Structure EC03OC91.004...

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

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Glass Impact Test Structure 1 Figure 1 to Subpart A of Part 1201 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT... 1 to Subpart A of Part 1201—Glass Impact Test Structure EC03OC91.004...

  17. 16 CFR Figure 1 to Subpart A of... - Glass Impact Test Structure

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Glass Impact Test Structure 1 Figure 1 to Subpart A of Part 1201 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT... 1 to Subpart A of Part 1201—Glass Impact Test Structure EC03OC91.004...

  18. 16 CFR Figure 1 to Subpart A of... - Glass Impact Test Structure

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Glass Impact Test Structure 1 Figure 1 to Subpart A of Part 1201 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT... 1 to Subpart A of Part 1201—Glass Impact Test Structure EC03OC91.004...

  19. 16 CFR Figure 1 to Subpart A of... - Glass Impact Test Structure

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Glass Impact Test Structure 1 Figure 1 to Subpart A of Part 1201 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT... 1 to Subpart A of Part 1201—Glass Impact Test Structure EC03OC91.004...

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

    SciTech Connect

    Gill, W.

    1981-01-01

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

  1. Characteristics of Twenty-Nine Aerosol Samplers Tested at U.S. Army Edgewood Chemical Biological Center (2000-2006)

    DTIC Science & Technology

    2011-02-01

    Particles 7 3. Summary of Samplers that use Impingement or Impaction in Liquid to Collect Particles 7 4. Summary of Samplers that use Impaction on a...wetted surfaces. Impaction is the mechanism used in air samplers to remove unneeded large particles from the air. Particle deposition by interception...These sampler characteristics are given in Appendixes 6-7 and Table 2. c. Samplers that use impingement and/or impaction onto a wetted surface: SKC

  2. The Adverse Impact of High Stakes Testing on Minority Students: Evidence from 100 Years of Test Data.

    ERIC Educational Resources Information Center

    Madaus, George F.; Clarke, Marguerite

    This paper examines four aspects of current high stakes testing that impact minority students and others traditionally underserved by American education. Data from research conducted at Boston College over 30 years highlight 4 issues: high stakes, high standards tests do not have a markedly positive effect on teaching and learning; high stakes…

  3. Is the psychological impact of genetic testing moderated by support and sharing of test results to family and friends?

    PubMed

    Lapointe, Julie; Dorval, Michel; Noguès, Catherine; Fabre, Roxane; Julian-Reynier, Claire

    2013-12-01

    Receiving the results of genetic tests for a breast and ovarian cancer susceptibility can be a stressful experience. Here we studied the effects of social support (SS) and the sharing of test results on the psychological impact of BRCA1/2 test result disclosure. We also compared carriers and non-carriers on sharing, SS and psychological impact. Five-hundred and twenty-two unaffected women were followed prospectively for 2 years after receiving their test results. Psychological impact was measured on the impact of event scale. Multivariate multi-level models were used, and all the analyses were stratified depending on mutation status (carriers vs non-carriers). Two weeks after receiving their BRCA1/2 results, carriers had shared their test results less frequently than non-carriers (p < 0.01). Sharing test results was not significantly associated with psychological impact. Availability of SS was significantly associated with better psychological adjustment across time among carriers (p < 0.01), but not among non-carriers. For female BRCA1/2 mutation carriers, the importance of SS should be stressed, and possible ways of enlisting people in their entourage for this purpose should be discussed in the context of clinical encounters.

  4. The Potential Impact of Not Being Able to Create Parallel Tests on Expected Classification Accuracy

    ERIC Educational Resources Information Center

    Wyse, Adam E.

    2011-01-01

    In many practical testing situations, alternate test forms from the same testing program are not strictly parallel to each other and instead the test forms exhibit small psychometric differences. This article investigates the potential practical impact that these small psychometric differences can have on expected classification accuracy. Ten…

  5. 49 CFR 572.176 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 70 percent for at least four hours prior to a test. (2) Mount the test material and secure it to a... 49 Transportation 7 2012-10-01 2012-10-01 false Knees and knee impact test procedure. 572.176... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST...

  6. 49 CFR 572.136 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... the test material and secure it to a rigid test fixture as shown in Figure O5. No part of the foot or... 49 Transportation 7 2011-10-01 2011-10-01 false Knees and knee impact test procedure. 572.136... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST...

  7. 49 CFR 572.176 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 70 percent for at least four hours prior to a test. (2) Mount the test material and secure it to a... 49 Transportation 7 2014-10-01 2014-10-01 false Knees and knee impact test procedure. 572.176... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST...

  8. 49 CFR 572.136 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... the test material and secure it to a rigid test fixture as shown in Figure O5. No part of the foot or... 49 Transportation 7 2014-10-01 2014-10-01 false Knees and knee impact test procedure. 572.136... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST...

  9. 49 CFR 572.136 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... the test material and secure it to a rigid test fixture as shown in Figure O5. No part of the foot or... 49 Transportation 7 2013-10-01 2013-10-01 false Knees and knee impact test procedure. 572.136... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST...

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

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... the test material and secure it to a rigid test fixture as shown in Figure O5. No part of the foot or... 49 Transportation 7 2010-10-01 2010-10-01 false Knees and knee impact test procedure. 572.136... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST...

  11. 49 CFR 572.176 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 70 percent for at least four hours prior to a test. (2) Mount the test material and secure it to a... 49 Transportation 7 2013-10-01 2013-10-01 false Knees and knee impact test procedure. 572.176... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST...

  12. 49 CFR 572.136 - Knees and knee impact test procedure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... the test material and secure it to a rigid test fixture as shown in Figure O5. No part of the foot or... 49 Transportation 7 2012-10-01 2012-10-01 false Knees and knee impact test procedure. 572.136... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) ANTHROPOMORPHIC TEST...

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

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

    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.

  14. Satellite Test of Radiation Impact on Ramtron 512K FRAM

    NASA Technical Reports Server (NTRS)

    MacLeod, Todd C.; Sayyah, Rana; Sims, W. Herb; Varnavas, Kosta A.; Ho, Fat D.

    2009-01-01

    The Memory Test Experiment is a space test of a ferroelectric memory device on a low Earth orbit satellite. The test consists of writing and reading data with a ferroelectric based memory device. Any errors are detected and are stored on board the satellite. The data is send to the ground through telemetry once a day. Analysis of the data can determine the kind of error that was found and will lead to a better understanding of the effects of space radiation on memory systems. The test will be one of the first flight demonstrations of ferroelectric memory in a near polar orbit which allows testing in a varied radiation environment. The memory devices being tested is a Ramtron Inc. 512K memory device. This paper details the goals and purpose of this experiment as well as the development process. The process for analyzing the data to gain the maximum understanding of the performance of the ferroelectric memory device is detailed.

  15. Demand characteristics of music affect performance on the Wonderlic Personnel Test Of Intelligence.

    PubMed

    Verpaelst, Celissa C; Standing, Lionel G

    2007-02-01

    This study examined whether demand characteristics concerning music can change subjects' performance on the Wonderlic Personnel Test of intelligence. Participants (N= 60) were randomly assigned and informed either that Mozart's music typically enhances cognitive performance or diminishes it. They then completed the Wonderlic Personnel Test while listening to a Mozart piano sonata. The subjects with a positive set answered significantly more items correctly on the test (14%) than those with a negative set (p = .03). This result may hold implications for the study of the 'Mozart effect'.

  16. Characteristic of retained austenite decomposition during tempering and its effect on impact toughness in SA508 Gr.3 steel

    NASA Astrophysics Data System (ADS)

    Yan, Guanghua; Han, Lizhan; Li, Chuanwei; Luo, Xiaomeng; Gu, Jianfeng

    2017-01-01

    Retained austenite(RA) usually presents in the quenched Nuclear Pressure-Vessel SA508 Gr.3 steel. In the present work, the characteristic of RA decomposition and its effect on the impact toughness were investigated by microstructure observation, dilatometric experiments and Charpy impact tests. The results show that the RA transformed into martensite and bainite during tempering at 230 °C and 400 °C respectively, while mixture of long rod carbides and ferrite formed at 650 °C. The long rod carbides formed from RA decomposition decrease the critical cleavage stress for initiation of micro-cracks, and deteriorate the impact toughness of the steel. Pre-tempering at a low temperature such as 230 °C or 400 °C leading to the decomposition of RA into martensite or baintie can eliminate the deterioration of the toughness caused by direct decomposition into long rod carbides. The absorbed energy indicate that pre-tempering at 400 °C can drive dramatically improvement in the toughness of the steel.

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

    ERIC Educational Resources Information Center

    Norris, Emily Mohajeri; Dwyer, Mary M.

    2005-01-01

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

  18. Impact as a general cause of extinction: A feasibility test

    NASA Astrophysics Data System (ADS)

    Raup, David M.

    Large body impact has been implicated as the possible cause of several extinction events. This is entirely plausible if one accepts two propositions: (1) that impacts of large comets and asteroids produce environmental effects severe enough to cause significant species extinctions and (2) that the estimates of comet and asteroid flux for the Phanerozoic are approximately correct. A resonable next step is to investigate the possibility that impact could be a significant factor in the broader Phanerozoic extinction record, not limited merely to a few events of mass extinction. Monte Carlo simulation experiments based on existing flux estimates and reasonable predictions of the relationship between bolide diameter and extinction are discussed. The simulation results raise the serious possibility that large body impact may be a more pervasive factor in extinction than has been assumed heretofore. At the very least, the experiments show that the comet and asteroid flux estimates combined with a reasonable kill curve produces a reasonable extinction record, complete with occasional mass extinctions and the irregular, lower intensity extinctions commonly called background extinction.

  19. Impact as a general cause of extinction: A feasibility test

    NASA Technical Reports Server (NTRS)

    Raup, David M.

    1988-01-01

    Large body impact has been implicated as the possible cause of several extinction events. This is entirely plausible if one accepts two propositions: (1) that impacts of large comets and asteroids produce environmental effects severe enough to cause significant species extinctions and (2) that the estimates of comet and asteroid flux for the Phanerozoic are approximately correct. A resonable next step is to investigate the possibility that impact could be a significant factor in the broader Phanerozoic extinction record, not limited merely to a few events of mass extinction. Monte Carlo simulation experiments based on existing flux estimates and reasonable predictions of the relationship between bolide diameter and extinction are discussed. The simulation results raise the serious possibility that large body impact may be a more pervasive factor in extinction than has been assumed heretofore. At the very least, the experiments show that the comet and asteroid flux estimates combined with a reasonable kill curve produces a reasonable extinction record, complete with occasional mass extinctions and the irregular, lower intensity extinctions commonly called background extinction.

  20. Cognitive dysfunction after on-pump operations: neuropsychological characteristics and optimal core battery of tests.

    PubMed

    Polunina, Anna G; Golukhova, Elena Z; Guekht, Alla B; Lefterova, Natalia P; Bokeria, Leo A

    2014-01-01

    Postoperative cognitive dysfunction (POCD) is a mild form of perioperative ischemic brain injury, which emerges as memory decline, decreased attention, and decreased concentration during several months, or even years, after surgery. Here we present results of our three neuropsychological studies, which overall included 145 patients after on-pump operations. We found that the auditory memory span test (digit span) was more effective as a tool for registration of POCD, in comparison with the word-list learning and story-learning tests. Nonverbal memory or visuoconstruction tests were sensitive to POCD in patients after intraoperative opening of cardiac chambers with increased cerebral air embolism. Psychomotor speed tests (digit symbol, or TMT A) registered POCD, which was characteristic for elderly atherosclerotic patients. Finally, we observed that there were significant effects of the order of position of a test on the performance on this test. For example, the postoperative performance on the core tests (digit span and digit symbol) showed minimal impairment when either of these tests was administered at the beginning of testing. Overall, our data shows that the selection of tests, and the order of which these tests are administered, may considerably influence the results of studies of POCD.

  1. Rationale for and dimensions of impact surfaces for biofidelity tests of different sizes of frontal and side impact dummies.

    PubMed

    Irwin, Annette L; Mertz, Harold J

    2010-11-01

    The biofidelity impact response corridors that were used to develop the Hybrid III family of dummies were established by scaling the various biofidelity corridors that were defined for the Hybrid III mid-size, adult male dummy. Scaling ratios for the responses of force, moment, acceleration, velocity, deflection, angle, stiffness and time were developed using dimensions and masses that were prescribed for the dummies. In addition, an elastic modulus ratio for bone was used to account for the differences between child and adult bone elastic properties. A similar method is being used by ISO/TC22/SC12/WG 5 to develop biofidelity guidelines for a family of side impact dummies based on scaling the biofidelity impact response corridors that are prescribed for WorldSID, a mid-size, adult male dummy. While the various biomechanical impact response requirements for the Hybrid III family of dummies and the WorldSID are documented in the literature, the scaling used to prescribe the dimensions of the impact surfaces that are used for the various biofidelity tests for various sizes of dummies are not documented. This paper describes the rationale for how these impact surfaces should be scaled, gives the scaling equations, and gives the dimensions of the impact surfaces that should be used for the various biofidelity tests of the different sizes of adult and child dummies. For future PMHS and human volunteer tests that are conducted to define impact biofidelity guidelines, it is recommended that the impact surfaces be scaled for the test subject size so that the data can be appropriately normalized to any size subject.

  2. Clinical characteristics of patients who test positive for Clostridium difficile by repeat PCR.

    PubMed

    Green, Daniel A; Stotler, Brie; Jackman, Dana; Whittier, Susan; Della-Latta, Phyllis

    2014-11-01

    The high sensitivity of PCR assays for diagnosing Clostridium difficile infection (CDI) has greatly reduced the need for repeat testing after a negative result. Nevertheless, a small subset of patients do test positive within 7 days of a negative test. The aim of this study was to evaluate the clinical characteristics of these patients to determine when repeat testing may be appropriate. The results of all Xpert C. difficile PCR (Cepheid, Sunnyvale CA) tests performed in the clinical microbiology laboratory at New York-Presbyterian Hospital, Columbia University Medical Center (NYPH/CUMC) from 1 May 2011 through 6 September 2013, were reviewed. A retrospective case-control study was performed, comparing patients who tested positive within 7 days of a negative test result to a random selection of 50 controls who tested negative within 7 days of a negative test result. During the study period, a total of 14,875 tests were performed, of which 1,066 were repeat tests (7.2%). Eleven of these repeat tests results were positive (1.0%). The only risk factor independently associated with repeat testing positive was history of a prior CDI (odds ratio [OR], 19.6 [95% confidence interval {CI}, 4.0 to 19.5], P < 0.001). We found that patients who test positive for C. difficile by PCR within 7 days of a negative test are more likely to have a history of CDI than are patients who test negative with repeat PCR. This finding may be due to the high rate of disease relapse or the increased likelihood of empirical therapy leading to false-negative results in these patients.

  3. SGC tests for influence of material composition on compaction characteristic of asphalt mixtures.

    PubMed

    Chen, Qun; Li, Yuzhi

    2013-01-01

    Compaction characteristic of the surface layer asphalt mixture (13-type gradation mixture) was studied using Superpave gyratory compactor (SGC) simulative compaction tests. Based on analysis of densification curve of gyratory compaction, influence rules of the contents of mineral aggregates of all sizes and asphalt on compaction characteristic of asphalt mixtures were obtained. SGC Tests show that, for the mixture with a bigger content of asphalt, its density increases faster, that there is an optimal amount of fine aggregates for optimal compaction and that an appropriate amount of mineral powder will improve workability of mixtures, but overmuch mineral powder will make mixtures dry and hard. Conclusions based on SGC tests can provide basis for how to adjust material composition for improving compaction performance of asphalt mixtures, and for the designed asphalt mixture, its compaction performance can be predicted through these conclusions, which also contributes to the choice of compaction schemes.

  4. Characteristics of Genomic Test Consumers Who Spontaneously Share Results with Their Health Care Provider

    PubMed Central

    Darst, Burcu F.; Madlensky, Lisa; Schork, Nicholas J.; Topol, Eric J.; Bloss, Cinnamon S.

    2013-01-01

    Purpose To evaluate the characteristics of direct-to-consumer (DTC) genomic test consumers who spontaneously shared their test results with their health care provider. Methods Utilizing data from the Scripps Genomic Health Initiative we compared demographic, behavioral, and attitudinal characteristics of DTC genomic test consumers who shared their results with their physician or health care provider versus those who did not share. We also compared genomic risk estimates between the two groups. Results Of 2024 individuals assessed at approximately 6 months post-testing, a total of 540 individuals (26.5%) reported sharing their results with their physician or health care provider. Those who shared were older (p<.001), had a higher income (p=.01), were more likely to be married (p=.005), and more likely to identify with a religion (p=.004). As assessed prior to undergoing testing, sharers also showed higher exercise (p=.003) and lower fat intake (p=.02), and expressed fewer overall concerns about testing (p=.001) and fewer concerns related to the privacy of their genomic information (p=.03). The genomic disease risk estimates disclosed were not associated with sharing. Conclusion In a DTC genomic testing context, physicians and other health care providers may be more likely to encounter patients who are more health conscious and have fewer concerns about the privacy of their genomic information. Genomic risk itself does not appear to be a primary determinant of sharing behavior among consumers. PMID:23384116

  5. Impact testing of the residual limb: System response to changes in prosthetic stiffness.

    PubMed

    Boutwell, Erin; Stine, Rebecca; Gard, Steven

    2016-01-01

    Currently, it is unknown whether changing prosthetic limb stiffness affects the total limb stiffness and influences the shock absorption of an individual with transtibial amputation. The hypotheses tested within this study are that a decrease in longitudinal prosthetic stiffness will produce (1) a reduced total limb stiffness, and (2) reduced magnitude of peak impact forces and increased time delay to peak force. Fourteen subjects with a transtibial amputation participated in this study. Prosthetic stiffness was modified by means of a shock-absorbing pylon that provides reduced longitudinal stiffness through compression of a helical spring within the pylon. A sudden loading evaluation device was built to examine changes in limb loading mechanics during a sudden impact event. No significant change was found in the peak force magnitude or timing of the peak force between prosthetic limb stiffness conditions. Total limb stiffness estimates ranged from 14.9 to 17.9 kN/m but were not significantly different between conditions. Thus, the prosthetic-side total limb stiffness was unaffected by changes in prosthetic limb stiffness. The insensitivity of the total limb stiffness to prosthetic stiffness may be explained by the mechanical characteristics (i.e., stiffness and damping) of the anatomical tissue within the residual limb.

  6. Physicochemical characteristics and droplet impact dynamics of superhydrophobic carbon nanotube arrays.

    PubMed

    Aria, Adrianus I; Gharib, Morteza

    2014-06-17

    The physicochemical and droplet impact dynamics of superhydrophobic carbon nanotube arrays are investigated. These superhydrophobic arrays are fabricated simply by exposing the as-grown carbon nanotube arrays to a vacuum annealing treatment at a moderate temperature. This treatment, which allows a significant removal of oxygen adsorbates, leads to a dramatic change in wettability of the arrays, from mildly hydrophobic to superhydrophobic. Such change in wettability is also accompanied by a substantial change in surface charge and electrochemical properties. Here, the droplet impact dynamics are characterized in terms of critical Weber number, coefficient of restitution, spreading factor, and contact time. Based on these characteristics, it is found that superhydrophobic carbon nanotube arrays are among the best water-repellent surfaces ever reported. The results presented herein may pave a way for the utilization of superhydrophobic carbon nanotube arrays in numerous industrial and practical applications, including inkjet printing, direct injection engines, steam turbines, and microelectronic fabrication.

  7. Simulation Study of Impact of Aeroelastic Characteristics on Flying Qualities of a High Speed Civil Transport

    NASA Technical Reports Server (NTRS)

    Raney, David L.; Jackson, E. Bruce; Buttrill, Carey S.

    2002-01-01

    A piloted simulation study conducted in NASA Langley Visual Motion Simulator addressed the impact of dynamic aero- servoelastic effects on flying qualities of a High Speed Civil Transport. The intent was to determine effectiveness of measures to reduce the impact of aircraft flexibility on piloting tasks. Potential solutions examined were increasing frequency of elastic modes through structural stiffening, increasing damping of elastic modes through active control, elimination of control effector excitation of the lowest frequency elastic modes, and elimination of visual cues associated with elastic modes. Six test pilots evaluated and performed simulated maneuver tasks, encountering incidents wherein cockpit vibrations due to elastic modes fed back into the control stick through involuntary vibrations of the pilots upper body and arm. Structural stiffening and compensation of the visual display were of little benefit in alleviating this impact, while increased damping and elimination of control effector excitation of the elastic modes both offered great improvements when applied in sufficient degree.

  8. A study on the performance and emission characteristics of esterified pinnai oil tested in VCR engine.

    PubMed

    Ashok Kumar, T; Chandramouli, R; Mohanraj, T

    2015-11-01

    Biodiesel is a clean renewable fuel derived from vegetable oils and animal fats. It is biodegradable, oxygenated, non toxic and free from sulfur and aromatics. The biodiesel prepared from pinnai oil undergoes acid esterification followed by alkaline transesterification process. The fatty acid methyl esters components were identified using gas chromatography and compared with the standard properties. The properties of biodiesel are comparable with diesel. The yield of the biodiesel production depends upon the process parameters such as reaction temperature, pH, time duration and amount of catalyst. The yield of biodiesel by transesterification process was 73% at 55°C. This fuel was tested in a variable compression ratio engine with blend ratios of B10 and B20. During the test runs the compression ratio of the engine was varied from 15:1 to 18:1 and the torque is adjusted from zero to maximum value of 22Nm. The performance characteristics such as the brake thermal efficiency, brake specific energy consumption and exhaust gas temperature of the engine are analyzed. The combustion characteristics of biodiesel like ignition delay, combustion duration and maximum gas temperature and the emission characteristics are also analyzed. The performance characteristics, combustion characteristics and engine emission are effective in the variable compression ratio engine with biodiesel and it is compared with diesel.

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

    ERIC Educational Resources Information Center

    Klenowski, Val; Wyatt-Smith, Claire

    2012-01-01

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

  10. The Impact of Time Limits on Test Behaviors.

    ERIC Educational Resources Information Center

    Lin, Miao-Hsiang

    Specific questions addressed in this study include how time limits affect a test's construct and predictive validities, how time limits affect an examinee's time allocation and test performance, and whether the assumption about how examinees answer items is valid. Interactions involving an examinee's sex and age are studied. Two parallel forms of…

  11. Impact of Educational Level on Performance on Auditory Processing Tests

    PubMed Central

    Murphy, Cristina F. B.; Rabelo, Camila M.; Silagi, Marcela L.; Mansur, Letícia L.; Schochat, Eliane

    2016-01-01

    Research has demonstrated that a higher level of education is associated with better performance on cognitive tests among middle-aged and elderly people. However, the effects of education on auditory processing skills have not yet been evaluated. Previous demonstrations of sensory-cognitive interactions in the aging process indicate the potential importance of this topic. Therefore, the primary purpose of this study was to investigate the performance of middle-aged and elderly people with different levels of formal education on auditory processing tests. A total of 177 adults with no evidence of cognitive, psychological or neurological conditions took part in the research. The participants completed a series of auditory assessments, including dichotic digit, frequency pattern and speech-in-noise tests. A working memory test was also performed to investigate the extent to which auditory processing and cognitive performance were associated. The results demonstrated positive but weak correlations between years of schooling and performance on all of the tests applied. The factor “years of schooling” was also one of the best predictors of frequency pattern and speech-in-noise test performance. Additionally, performance on the working memory, frequency pattern and dichotic digit tests was also correlated, suggesting that the influence of educational level on auditory processing performance might be associated with the cognitive demand of the auditory processing tests rather than auditory sensory aspects itself. Longitudinal research is required to investigate the causal relationship between educational level and auditory processing skills. PMID:27013958

  12. Unintended and Unwelcome: The Local Impact of State Testing.

    ERIC Educational Resources Information Center

    Corbett, H. Dickson; Wilson, Bruce L.

    This paper summarizes the results of a study of the local consequences of implementing statewide minimum competency tests. For American education to be the best in the world, the use of statewide and nationwide standardized testing as a primary policy tool for stimulating reform must be discontinued. Second, school district responses to such…

  13. Residential mobility impacts exposure assessment and community socioeconomic characteristics in longitudinal epidemiology studies

    PubMed Central

    Brokamp, Cole; LeMasters, Grace K; Ryan, Patrick H

    2016-01-01

    Epidemiologic studies commonly use residential locations to estimate environmental exposures or community-level characteristics. The impact of residential mobility on these characteristics, however, is rarely considered. The objective of this analysis was to examine the effect of residential mobility on estimates of traffic-related air pollution (TRAP), greenspace, and community-level characteristics. All residential addresses were reported from birth through age seven for children enrolled in the Cincinnati Childhood Allergy and Air Pollution Study. Exposure to TRAP at each address was estimated using a land use model. Greenspace was estimated using satellite imagery. Indices of neighborhood deprivation and race were created based on socioeconomic-census tract measures. Exposure estimates using the birth record address, the last known address, and the annual address history were used to determine exposure estimation error and bias in the association with asthma at age seven. Overall, 54% of the cohort moved at least once prior to age seven. Each move was separated by a median of 4 miles and associated with a median decrease of 4.4% in TRAP exposure, a 5.3% increase in greenspace, an improved deprivation index, and no change in the race index. Using the birth record address or the last known address instead of the annual address history resulted in exposure misclassification leading to a bias toward the null when associating the exposures with asthma. Using a single address to estimate environmental exposures and community-level characteristics over a time period may result in differential assessment error. PMID:26956935

  14. The Impact of Hospital Closures and Hospital and Population Characteristics on Increasing Emergency Department Volume: A Geographic Analysis

    PubMed Central

    Carr, Brendan G.; Smith, Tony E.; Tran, Van C.; Polsky, Daniel; Branas, Charles C.

    2015-01-01

    Abstract Emergency visits are rising nationally, whereas the number of emergency departments is shrinking. However, volume has not increased uniformly at all emergency departments. It is unclear what factors account for this variability in emergency volume growth rates. The objective of this study was to test the association of hospital and population characteristics and the effect of hospital closures with increases in emergency department volume. The study team analyzed emergency department volume at New York State hospitals from 2004 to 2010 using data from cost reports and administrative databases. Multivariate regression was used to evaluate characteristics associated with emergency volume growth. Spatial analytics and distances between hospitals were used in calculating the predicted impact of hospital closures on emergency department use. Among the 192 New York hospitals open from 2004 to 2010, the mean annual increase in emergency department visits was 2.7%, but the range was wide (-5.5% to 11.3%). Emergency volume increased nearly twice as fast at tertiary referral centers (4.8%) and nonurban hospitals (3.7% versus urban at 2.1%) after adjusting for other characteristics. The effect of hospital closures also strongly predicted variation in growth. Emergency volume is increasing faster at specific hospitals: tertiary referral centers, nonurban hospitals, and those near hospital closures. This study provides an understanding of how emergency volume varies among hospitals and predicts the effect of hospital closures in a statewide region. Understanding the impact of these factors on emergency department use is essential to ensure that these populations have access to critical emergency services. (Population Health Management 2015;18:459–466) PMID:25658768

  15. Aerodynamic characteristics of the Scout 133R vehicle determined from wind tunnel tests

    NASA Technical Reports Server (NTRS)

    Abramson, F. B.; Muir, T. G., Jr.; Simmons, H. L.

    1972-01-01

    Bending moments and other associated parameters were measured on a Scout vehicle during a launch through high velocity horizontal winds. Comparison of the measured data with predictions revealed some unexplained discrepancies. Possible sources of error in the experimental data and predictions were considered; one of which is the predicted aerodynamic characteristics. A wind tunnel investigation was initiated, including supersonic force and pressure tests, to better define the aerodynamics. In addition to basic aerodynamic coefficients from the force test, detailed pressure and load distributions along the body were established from the pressure test. Pressure coefficients were integrated to determine normal load distributions, total normal force, and total pitching moment of the body. Comparison of the normal forces from pressure and force tests resulted in agreement within 15%. Comparison of pitching moment data from the two tests resulted in larger differences.

  16. Testing and Resilience of the Impact Origin of the Moon

    NASA Technical Reports Server (NTRS)

    Righter, K.; Canup, R. M.

    2016-01-01

    The leading hypothesis for the origin of the Moon is the giant impact model, which grew out of the post-Apollo science community. The hypothesis was able to explain the high E-M system angular momentum, the small lunar core, and consistent with the idea that the early Moon melted substantially. The standard hypothesis requires that the Moon be made entirely from the impactor, strangely at odds with the nearly identical oxygen isotopic composition of the Earth and Moon, compositions that might be expected to be different if Moon came from a distinct impactor. Subsequent geochemical research has highlighted the similarity of both geochemical and isotopic composition of the Earth and Moon, and measured small but significant amounts of volatiles in lunar glassy materials, both of which are seemingly at odds with the standard giant impact model. Here we focus on key geochemical measurements and spacecraft observations that have prompted a healthy re-evaluation of the giant impact model, provide an overview of physical models that are either newly proposed or slightly revised from previous ideas, to explain the new datasets.

  17. IMPACT_S: integrated multiprogram platform to analyze and combine tests of selection.

    PubMed

    Maldonado, Emanuel; Sunagar, Kartik; Almeida, Daniela; Vasconcelos, Vitor; Antunes, Agostinho

    2014-01-01

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

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

    SciTech Connect

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

    1997-04-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-07-01

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

  20. Study on the measurement system of the target polarization characteristics and test

    NASA Astrophysics Data System (ADS)

    Fu, Qiang; Zhu, Yong; Zhang, Su; Duan, Jin; Yang, Di; Zhan, Juntong; Wang, Xiaoman; Jiang, Hui-Lin

    2015-10-01

    The polarization imaging detection technology increased the polarization information on the basis of the intensity imaging, which is extensive application in the military and civil and other fields, the research on the polarization characteristics of target is particularly important. The research of the polarization reflection model was introduced in this paper, which describes the scattering vector light energy distribution in reflecting hemisphere polarization characteristics, the target polarization characteristics test system solutions was put forward, by the irradiation light source, measuring turntable and camera, etc, which illuminate light source shall direct light source, with laser light sources and xenon lamp light source, light source can be replaced according to the test need; Hemispherical structure is used in measuring circumarotate placed near its base material sample, equipped with azimuth and pitching rotation mechanism, the manual in order to adjust the azimuth Angle and high Angle observation; Measuring camera pump works, through the different in the way of motor control polaroid polarization test, to ensure the accuracy of measurement and imaging resolution. The test platform has set up by existing laboratory equipment, the laser is 532 nm, line polaroid camera, at the same time also set the sending and receiving optical system. According to the different materials such as wood, metal, plastic, azimuth Angle and zenith Angle in different observation conditions, measurement of target in the polarization scattering properties of different exposure conditions, implementation of hemisphere space pBRDF measurement.

  1. IXV Mock-Up Water Impact Test and Results Correlation

    NASA Astrophysics Data System (ADS)

    Ullio, R.; Becchio, V.; D'Amico, J.; Di Vita, G.

    2012-07-01

    In the frame of the ESA FLPP/IXV project one of the main goal is to validate the simulation methodology defined by TAS-I for the estimation of the maximum expected loads generated during splashdown event. Numerical results, obtained in different vehicle attitudes and landing conditions, were compared with experimental results from a reduced-scale drop test campaign, carried out making use of a rigid IXV vehicle scaled mock-up (1/4 of the IXV vehicle size). The test campaign was performed in the CNR-INSEAN (Istituto Nazionale per Studied Esperienze di Architettura Navale) facilities in Rome. In this paper firstly the engineering evaluation of the test results are discussed especially with respect to the selection of the best attitude candidate for landing. Then, the comparison of the test/analysis correlation activity is presented, and the related outcomes are evaluated in order to reduce the model factor uncertainty and enhance the derivation of the splashdown loads.

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  3. Prognostic impact of stress testing in coronary artery disease

    SciTech Connect

    Severi, S.; Michelassi, C. )

    1991-05-01

    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.

  4. Mechanical characteristics of plastic base Ports and impact on flushing efficacy

    PubMed Central

    Guiffant, Gérard; Flaud, Patrice; Royon, Laurent; Burnet, Espérie; Merckx, Jacques

    2017-01-01

    Background Three types of totally implantable venous access devices, Ports, are currently in use: titanium, plastic (polyoxymethylene, POM), and mixed (titanium base with a POM shell). Physics theory suggests that the interaction between a non-coring needle (NCN, made of stainless steel) and a plastic base would lead to the stronger material (steel) altering the more malleable material (plastic). Objectives To investigate whether needle impacts can alter a plastic base’s surface, thus potentially reducing flushing efficacy. Study design and methods A Port made of POM was punctured 200 times with a 19-gauge NCN. Following the existing guidelines, the needle tip pricked the base with each puncture. The Port’s base was then examined using a two-dimensional optical instrument, and a bi-dimensional numerical simulation using COMSOL® was performed to investigate potential surface irregularities and their impact on fluid flow. Results Each needle impact created a hole (mean depth, 0.12 mm) with a small bump beside it (mean height, 0.02 mm) the Reynolds number Rek≈10. A numerical simulation of the one hole/bump set showed that the flushing efficacy was 60% that of flushing along a flat surface. Discussion In clinical practice, the number of times a Port is punctured depends on patient and treatment characteristics, but each needle impact on the plastic base may increase the risk of decreased flushing effectiveness. Therefore, the more a plastic Port is accessed, the greater the risk of microorganisms, blood products, and medication accumulation. Conclusions Multiple needle impacts created an irregular surface on the Port’s base, which decreased flushing efficacy. Clinical investigation is needed to determine whether plastic base Ports are associated with an increased risk of Port infection and occlusion compared to titanium base Ports. PMID:28176897

  5. Large-scale aerodynamic characteristics of airfoils as tested in the variable density wind tunnel

    NASA Technical Reports Server (NTRS)

    Jacobs, Eastman N; Anderson, Raymond F

    1931-01-01

    In order to give the large-scale characteristics of a variety of airfoils in a form which will be of maximum value, both for airplane design and for the study of airfoil characteristics, a collection has been made of the results of airfoil tests made at full-scale values of the reynolds number in the variable density wind tunnel of the National Advisory Committee for Aeronautics. They have been corrected for tunnel wall interference and are presented not only in the conventional form but also in a form which facilitates the comparison of airfoils and from which corrections may be easily made to any aspect ratio. An example showing the method of correcting the results to a desired aspect ratio has been given for the convenience of designers. In addition, the data have been analyzed with a view to finding the variation of the aerodynamic characteristics of airfoils with their thickness and camber.

  6. The role of the modified taylor impact test in dynamic material research

    NASA Astrophysics Data System (ADS)

    Bagusat, Frank; Rohr, Ingmar

    2015-09-01

    Dynamic material research with strain rates of more than 1000 1/s is experimentally very often done with a Split-Hopkinson Bar, Taylor impact tests or planar plate impact test investigations. At the Ernst-Mach-Institut (EMI), a variant of an inverted classical Taylor impact test is used by application of velocity interferometers of the VISAR type ("Modified Taylor Impact Test", MTT). The conduction of the experiments is similar to that of planar plate impact tests. The data reduction and derivation of dynamic material data can also be restricted to an analysis of the VISAR signal. Due to these properties, nearly each highly dynamic material characterization in our institute done by planar plate investigations is usually accompanied by MTT experiments. The extended possibilities and usefulness of a combined usage of these two highly dynamic characterization methods are explained. Recently, further developed MTT experiments with very small specimen sizes are presented. For the first time, Taylor impact and planar impact specimen can be used for which the load directions even in case of thin plate test material are identical and not perpendicular to each other. Consequences for testing construction elements are discussed.

  7. Landing Characteristics of a Re-entry Vehicle with a Passive Landing System for Impact Alleviation

    NASA Technical Reports Server (NTRS)

    1963-01-01

    Landing Characteristics of a Re-entry Vehicle with a Passive Landing System for Impact Alleviation. An experimental investigation was made to determine the landing characteristics of a 1/8-scale dynamic model of a reentry vehicle using a passive landing system to alleviate the landing-impact loads. The passive landing system consisted of a flexible heat shield with a small section of aluminum honeycomb placed between the heat shield and the crew compartment at the point that would be the first to contact the landing surface. The model was landed on concrete and sand landing surfaces at parachute letdown velocities. The investigations simulated a vertical velocity of 30 ft/sec (full scale), horizontal velocities of 0, 15, 30, 40, and 50 ft/sec (full scale), and landing attitudes ranging from -30 degrees to 20 degrees. The model investigation indicated that stable landings could be made on a concrete surface at horizontal velocities up to about 30 ft/sec, but the stable landing-attitude range at these speeds was small. The aluminum honeycomb bottomed occasionally during landings on concrete. When bottoming did not occur, maximum normal and longitudinal accelerations at the center of gravity of the vehicle were approximately 50g and 30g, respectively. [Entire movie available on DVD from CASI as Doc ID 20070030981. Contact help@sti.nasa.gov

  8. Impact of sludge retention time on sludge characteristics and microbial community in MBR.

    PubMed

    Su, Yuchun; Pan, Jill Ruhsing; Huang, Chihpin; Chang, Chialing

    2011-01-01

    In this study, the impact of sludge retention time (SRT) on sludge characteristics and microbial community and the effect on membrane fouling in membrane bioreactor (MBR) was investigated. The results show that MBR with longer SRT has less fouling propensity, in agreement with other studies, despite the fact that the MBR with longer SRT contained higher MLSS and smaller particle size. However, much more soluble microbial products (SMPs) were released in MBR with shorter SRT. More slime on the membrane surface was observed in MBR with shorter SRT while sludge cakes formed on the membrane surface in MBR with longer SRT. The results show that SMP contributes to the severe fouling observed in MBR with shorter SRT, which is in agreement with other studies showing that SMPs were the major foulants in MBR. Under different SRTs of operation, the bacterial community structures of the sludge obtained by use of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) were almost identical, but those on the membrane surface differed substantially. It suggests that, although SRT has impact on sludge characteristics, it doesn't affect the microbial community in the suspension.

  9. Numerical Simulation on the Damage Characteristics of Ice Targets by Projectile Hypervelocity Impact

    NASA Astrophysics Data System (ADS)

    Wei, Zhang; Gang, Wei; Zhong-Cheng, Mu; Chang, Liu

    2009-12-01

    Interpretation of cratering records on planetary surfaces including the Earth has primarily been concerned with rocky surfaces, most notably the lunar surface and more recently Mars and Venus. Recently, the survey of craters on icy surfaces in the Solar System has been augmented by data from spacecraft close encounters, such as the Galileo mission to the Jovian system. To fully understand these cratering records, the physics of hypervelocity impacts needs to be understood. The numerical simulation on the damage characteristics of ice targets by projectile normal hypervelocity impact has been performed using the hydro-code AUTODYN. The 1 mm spherical projectile is aluminum 2017 alloy. The targets are water ice. The simulation velocities were in the range of 1 km/s-10 km/s. The damage characteristics include peak ejection angle, maximum crater depth and diameter etc. The simulation results are given and compared with the experimental results of Shrine et al. 2002. The simulation results are consistent with the experimental results.

  10. Numerical Simulation on the Damage Characteristics of Ice Targets by Projectile Hypervelocity Impact

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Wei, Gang; Mu, Zhong-Cheng

    2009-06-01

    Interpretation of cratering records on planetary surfaces including the Earth has primarily been concerned with rocky surfaces, most notably the lunar surface and more recently Mars and Venus. Recently, the survey of craters on icy surfaces in the Solar System has been augmented by data from spacecraft close encounters, such as the Galileo mission to the jovian system. To fully understand these cratering records, the physics of hypervelocity impacts needs to be understood. The numerical simulation on the damage characteristics of ice targets by projectile normally hypervelocity impact has been performed using the hydro-code AUTODYN. The 1mm spherical projectile is aluminum 2017 alloy. The targets are water ice. The simulation velocities were in the range of 1km/s-10km/s. The material models are consisted of Tillotson and Polynomial equation of state, Mohr-Coulomb and Johnson-Holmqiust strength model and Johnson-Holmqiust and principle stress failure model. The damage characteristics include peak ejection angle, peak temperature and pressure, maximum crater depth and diameter etc. The simulation results are given and compared with the experimental results of Burchell 2002. The simulation results are consistent very well with the experimental results.

  11. Impact of baseline characteristics on outcomes of carotid artery stenting in acute ischemic stroke patients

    PubMed Central

    Yu, Cheng-Sheng; Lin, Chih-Ming; Liu, Chi-Kuang; Lu, Henry Horng-Shing

    2016-01-01

    Carotid artery stenting is an effective treatment for ischemic stroke patients with moderate-to-severe carotid artery stenosis. However, the midterm outcome for patients undergoing this procedure varies considerably with baseline characteristics. To determine the impact of baseline characteristics on outcomes following carotid artery stenting, data from 107 eligible patients with a first episode of ischemic stroke were collected by retrospective chart review. A modified Rankin Scale (mRS) was used to divide patients into two baseline groups, mRS ≤2 and mRS >2. A three-step decision-tree statistical analysis was conducted. After weighting the decision-tree parameters, the following impact hierarchy was obtained: admission low-density lipoprotein, gouty arthritis, chronic kidney disease, ipsilateral common carotid artery resistance index, contralateral ophthalmic artery resistance index, sex, and dyslipidemia. The finite-state machine model demonstrated that, in patients with baseline mRS ≤2, 46% had an improved mRS score at follow-up, whereas 54% had a stable mRS score. In patients with baseline mRS >2, a stable mRS score was observed in 75%, improved score in 23%, and a poorer score in 2%. Admission low-density lipoprotein was the strongest predictive factor influencing poststenting outcome. In addition, our study provides further evidence that carotid artery stenting can be of benefit in first-time ischemic stroke patients with baseline mRS scores >2. PMID:27099508

  12. The impact of personality characteristics on the clinical expression in neurodegenerative disorders--a review.

    PubMed

    von Gunten, Armin; Pocnet, Cornelia; Rossier, Jérôme

    2009-10-28

    Clinical experience suggests that longstanding personality characteristics as a person's most distinctive features of all are likely to play a role in how someone with dementia copes with his increasing deficiencies. Personality characteristics may have a pathoplastic effect on both behavioral and psychological symptoms (BPS) or on cognition as well as cognitive decline. Cognitive disorders accompanied by BPS are a tremendous burden for both the patient and their proxies. This review suggests that premorbid personality characteristics are co-determinants of BPS in cognitive disorders, but much effort is needed to clarify whether or not specific premorbid personality traits are associated with specific BPS as no strong links have so far emerged. This review further shows that a growing field of research is interested in the links not only between quite short-lived emotional states and cognitive processes, but also between longstanding personality traits and cognition in both healthy individuals and patients with neurodegenerative disorders. Furthermore, a few studies found that specific premorbid personality traits may be risk factors for neurodegenerative diseases. However, research findings in this area remain scarce despite a huge literature on personality and cognitive disorders in general. An important shortcoming that hampers so far the progress of our understanding in these domains is the confusion in the literature between longstanding premorbid personality traits and transient personality changes observed in neurodegenerative diseases. Few studies have based their assessments on accepted personality theories and carefully investigated premorbid personality traits in patients with cognitive disorders, although assessing personality may be complicated in these patients. Studying the impact of personality characteristics in cognitive disorders is an especially promising field of research in particular when concomitantly using neurobiological approaches, in

  13. Usefulness of sediment toxicity tests with estuarine plants and animals to indicate municipal and industrial effluent impact

    SciTech Connect

    Lewis, M.A.; Weber, D.E.

    1994-12-31

    The environmental impact of municipal and industrial effluents has been predicted from results from single species toxicity tests. The goal of these tests is to ensure that water quality criteria and the designated use of the waterbody is not impacted. Recently, the focus of some effluent toxicity evaluation has centered on determining the effluent impact on the sediment in the receiving water. This study evaluated the toxicities of several sediment samples collected above and below six outfalls to the Pensacola Bay system. Toxicities were determined using three macrophytic plants and four animal species. The sediments, with few exceptions, exhibited a low level of toxicity. The mysid shrimp was more sensitive than Ampelisca, Leptocheirus and the sheepshead minnow. The sensitivities of the plants, Echinochloa crusgalli, Scirpus robustus and Sesbania macrocarpa, were comparable to those of the animal species. The toxicity of time sediment, when compared to that of the effluent, determined using standard single species of plants and animals was less. Overall, the sediment toxicity tests were useful in providing insight on the impact of effluents. However, the application and usefulness of this assessment tool is highly dependent upon a variety of factors, including the geomorphological characteristics of the receiving waters.

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

    PubMed

    Pham, Minh; Clark, Christina; Mckenna, John

    2012-08-01

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

  15. Characteristics, finite element analysis, test description, and preliminary test results of the STM4-120 kinematic Stirling engine

    SciTech Connect

    Linker, K.L.; Rawlinson, K.S.; Smith, G.

    1991-10-01

    The Department of Energy`s Solar Thermal Program has as one of its program elements the development and evaluation of conversion device technologies applicable to dish-electric systems. The primary research and development combines a conversion device (heat engine), solar receiver, and generator mounted at the focus of a parabolic dish concentrator. The Stirling-cycle heat engine was identified as the conversion device for dish-electric with the most potential for meeting the program`s goals for efficiency, reliability, and installed cost. To advance the technology toward commercialization, Sandia National Laboratories has acquired a Stirling Thermal Motors, Inc., kinematic Stirling engine, STM4-120, for evaluation. The engine is being bench-tested at Sandia`s Engine Test Facility and will be combined later with a solar receiver for on-sun evaluation. This report presents the engine characteristics, finite element analyses of critical engine components, test system layout, instrumentation, and preliminary performance results from the bench test.

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  17. Spin-Entry Characteristics of a Large Supersonic Bomber as Determined by Dynamic Model Tests

    NASA Technical Reports Server (NTRS)

    Bowman, James S.

    1965-01-01

    An investigation has been conducted in the Langley spin tunnel and at a catapult launch facility of a 1/60-scale dynamic model to determine the spin-entry characteristics of a large supersonic bomber. Catapult tests indicated that spin-entry motions were obtainable for a center-of-gravity location of 0.21 mean aerodynamic chord but were not obtainable at a center-of-gravity location of 0.25 mean aerodynamic chord. Deflected ailerons were effective in promoting or preventing the spin- entry motion and this effect was qualitatively the same as it was for the fully developed spin. Varying the configuration had little significant effect on the spin-entry characteristics. Brief tests conducted with the model in the Langley spin tunnel indicated that fully developed spins were obtainable at the forward center-of-gravity location and that spins were highly unlikely at the rearward center-of-location.

  18. Crack initiation and growth characteristics in SiC/SiC under indentation test

    NASA Astrophysics Data System (ADS)

    Zhang, W.; Hinoki, T.; Katoh, Y.; Kohyama, A.; Noda, T.; Muroga, T.; Yu, J.

    1998-10-01

    The mechanical behavior of ceramic matrix composites (CMC) is known to be strongly influenced by fiber-matrix interfacial properties and there have been many efforts to clarify the interfacial characteristics. To understand the fracture mechanism of the materials it is necessary to clarify how the cracks initiate and propagate among fibers, interphase (coating) and matrix. The objective of this study is to investigate crack initiation and growth characteristics in SiC/SiC composites with variations in coating thickness and coating methods by means of micro-indentation technique. Micro-indentation tests and hardness tests were carried out on SiC/SiC composites produced by the chemical vapour infiltration (CVI) process. The intrinsic catastrophic mode of failure of the brittle composite was prevented by application of single carbon and multiple coatings on fibers. Thinner coatings are sensitive to make fibers debonded and may improve the toughness of the composites.

  19. The Impact of Teachers' Characteristics and Self-Reported Practices on Students' Algebra Achievement

    ERIC Educational Resources Information Center

    Cope, Liza M.

    2013-01-01

    This study examined the impact of teachers' characteristics and self-reported practices on students' Algebra achievement while controlling for students' characteristics. This study is based on the secondary analysis of data collected from a nationally representative sample of 9 th grade students and their mathematics teachers during…

  20. Determinants of Timely Completion: The Impact of Bachelor's Degree Programme Characteristics and Student Motivation on Study Progress

    ERIC Educational Resources Information Center

    Suhre, Cor J. M.; Jansen, Ellen P. W. A.; Torenbeek, M.

    2013-01-01

    Timely completion of university degree programmes is a topic of growing concern to higher education institutions and their students. This paper reports on a study about the impact of degree programme characteristics and student motivation on study progress. The setting for the study is a Dutch law school. Data on degree programme characteristics,…

  1. Assessing the Impact of Harassment by Peers: Incident Characteristics and Outcomes in a National Sample of Youth

    ERIC Educational Resources Information Center

    Turner, Heather A.; Mitchell, Kimberly J.; Jones, Lisa; Shattuck, Anne

    2017-01-01

    Although there are widely held assumptions about the characteristics of peer bullying that are of greatest concern, very few studies have empirically assessed which characteristics most affect its impact. The current research addresses this gap by using a nationally representative U.S. sample of youth ages 10-20 to examine the relative effects of…

  2. A benchmark test of accuracy and precision in estimating dynamical systems characteristics from a time series.

    PubMed

    Rispens, S M; Pijnappels, M; van Dieën, J H; van Schooten, K S; Beek, P J; Daffertshofer, A

    2014-01-22

    Characteristics of dynamical systems are often estimated to describe physiological processes. For instance, Lyapunov exponents have been determined to assess the stability of the cardio-vascular system, respiration, and, more recently, human gait and posture. However, the systematic evaluation of the accuracy and precision of these estimates is problematic because the proper values of the characteristics are typically unknown. We fill this void with a set of standardized time series with well-defined dynamical characteristics that serve as a benchmark. Estimates ought to match these characteristics, at least to good approximation. We outline a procedure to employ this generic benchmark test and illustrate its capacity by examining methods for estimating the maximum Lyapunov exponent. In particular, we discuss algorithms by Wolf and co-workers and by Rosenstein and co-workers and evaluate their performances as a function of signal length and signal-to-noise ratio. In all scenarios, the precision of Rosenstein's algorithm was found to be equal to or greater than Wolf's algorithm. The latter, however, appeared more accurate if reasonably large signal lengths are available and noise levels are sufficiently low. Due to its modularity, the presented benchmark test can be used to evaluate and tune any estimation method to perform optimally for arbitrary experimental data.

  3. Population-based Testing and Treatment Characteristics for Chronic Myelogenous Leukemia

    PubMed Central

    Styles, Timothy; Wu, Manxia; Wilson, Reda; Babcock, Frances; Butterworth, David; West, Dee W.; Richardson, Lisa C.

    2017-01-01

    Introduction National and International Hematology/Oncology Practice Guidelines recommend testing for the BCR-ABL mutation for definitive diagnosis of chronic myeloid leukemia (CML) to allow for appropriate treatment with a Tyrosine Kinase Inhibitor (TKI). The purpose of our study was to describe population-based testing and treatment practice characteristics for patients diagnosed with CML. Methods We analyzed cases of CML using 2011 data from 10 state registries which are part of the Centers for Disease Control and Prevention’s (CDC) National Program of Cancer Registries. We describe completeness of testing for the BCR-ABL gene and availability of outpatient treatment with TKIs and associated characteristics. Results A total of 685 cases of CML were identified; 55% (374) had a documented BCR-ABL gene test with 96% (360) of these being positive for the BCR-ABL gene and the remaining 4% (14) either testing negative or had a missing result. Registries were able to identify the use of TKIs in 54% (369) of patients, though only 43% (296) had a corresponding BCR-ABL gene test documented. One state registry reported a significantly lower percentage of patients being tested for the BCR-ABL gene (25%) and receiving TKI treatment (21%). Limiting analysis to CML case reports from the remaining nine CER registries, 78% (305) patients had a documented BCR-ABL gene test and 79% (308) had documented treatment with a TKI. Receipt of testing or treatment for these nine states did not vary by sex, race, ethnicity, census tract poverty level, census tract urbanization, or insurance status; BCR-ABL testing varied by state of residence and BCR-ABL testing and TKI therapy occurred less often with increasing age (OR: 0.97, 95%CI: 0.95–0.99; OR: 0.97, 95%CI: 0.96–0.99 respectively). Conclusions Collection of detailed CML data vary significantly by states. A majority of the case patients had appropriate testing for the BCR-ABL gene and treatment with tyrosine kinase inhibitors

  4. Estimation of the Operating Characteristics When the Test Information of the Old Test Is Not Constant. I: Rationale. Research Report 80-2.

    ERIC Educational Resources Information Center

    Samejima, Fumiko

    Many combinations of a method and an approach for estimating the operating characteristics of the graded item responses, without assuming any mathematical forms, have been produced. In these methods, a set of items whose characteristics are known, or Old Test, is used, which has a large, constant amount of test information throughout the interval…

  5. Impact of musical experience on the Seashore Rhythm Test.

    PubMed

    Karzmark, P

    2001-08-01

    The Seashore Rhythm Test (SRT) is sensitive to musical talent. The possibility that this reduces its clinical sensitivity in cognitively impaired persons with musical experience was investigated. Subjects were 101 referrals to the neuropsychology service of a large medical center. The results indicate that patients with a substantial amount of musical experience tend to perform normally on the SRT, even when overall performance on a neuropsychological test battery suggests cognitive impairment. This finding suggests caution in interpreting normal SRT results in those with a musical background.

  6. Characteristics of hypervelocity impact craters on LDEF experiment S1003 and implications of small particle impacts on reflective surfaces

    NASA Technical Reports Server (NTRS)

    Mirtich, Michael J.; Rutledge, Sharon K.; Banks, Bruce A.; Devries, Christopher; Merrow, James E.

    1993-01-01

    The Ion Beam textured and coated surfaces EXperiment (IBEX), designated S1003, was flown on LDEF at a location 98 deg in a north facing direction relative to the ram direction. Thirty-six diverse materials were exposed to the micrometeoroid (and some debris) environment for 5.8 years. Optical property measurements indicated no changes for almost all of the materials except S-13G, Kapton, and Kapton-coated surfaces, and these changes can be explained by other environmental effects. From the predicted micrometeoroid flux of NASA SP-8013, no significant changes in optical properties of the surfaces due to micrometeoroids were expected. There were hypervelocity impacts on the various diverse materials flown on IBEX, and the characteristics of these craters were documented using scanning electron microscopy (SEM). The S1003 alumigold-coated aluminum cover tray was sectioned into 2 cm x 2 cm pieces for crater documentation. The flux curve generated from this crater data fits well between the 1969 micrometeoroid model and the Kessler debris model for particles less than 10(exp -9) gm which were corrected for the S1003 positions (98 deg to ram). As the particle mass increases, the S1003 impact data is greater than that predicted by even the debris model. This, however, is consistent with data taken on intercostal F07 by the Micrometeoroid/Debris Special Investigating Group (M/D SIG). The mirrored surface micrometeoroid detector flown on IBEX showed no change in solar reflectance and corroborated the S1003 flux curve, as well as results of this surface flown on SERT 2 and OSO 3 for as long as 21 years.

  7. [The characteristics of Alzheimer's Disease Units in relation to neuropsychological tests].

    PubMed

    Sorrentino, Giacoma C; Caffari, Bruno; Vanacore, Nicola; Maggini, Marina; Raschetti, Roberto

    2005-01-01

    The Cronos Project is a post-marketing surveillance study implemented by the Italian Ministry of Health and the National Institute of Health whose main objectives are to characterise the population of Alzheimer's disease patients treated with acetylcholinesterase inhibitors and monitor effectiveness and drug safety in the field practice. In this project 503 Alzheimer's disease units were activated located throughout the country. The characteristics of these Alzheimer's disease units are presented for setting (territorial, university, hospital, extra-hospital), health personnel employed, examinations offered (CT and MRI scans and laboratory tests), counselling activities and relationship with caregiver associations in relation to neuropsychological tests.

  8. Test of spectral emission and absorption characteristics of active optical fibers by direct side pumping.

    PubMed

    Zhang, Jianzhong; Luo, Yanhua; Sathi, Zinat M; Azadpeyma, Nilram; Peng, Gang-Ding

    2012-08-27

    Emission and absorption are two main properties of active optical fibers that are important for fiber amplifiers and lasers. We propose a direct side pumping scheme for non-deconstructive evaluation of active optical fibers. This scheme enables a simple in situ test of both emission and absorption characteristics without cutting fiber and produces good accuracy with very low pumping background. A commercial Er-doped fiber and a home-made Bi/Er co-doped optical fiber have been tested to demonstrate that the scheme is a useful alternative technique for characterizing active optical fiber or waveguides.

  9. The characteristics of 78 related airfoil sections from tests in the variable-density wind tunnel

    NASA Technical Reports Server (NTRS)

    Jacobs, Eastman N; Ward, Kenneth E; Pinkerton, Robert M

    1933-01-01

    An investigation of a large group of related airfoils was made in the NACA variable-density wind tunnel at a large value of the Reynolds number. The tests were made to provide data that may be directly employed for a rational choice of the most suitable airfoil section for a given application. The variation of the aerodynamic characteristics with variations in thickness and mean-line form were systematically studied. (author)

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Vassilakos, Gregory J.

    2014-01-01

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

  12. Characteristics and impact of animal models used for sports medicine research.

    PubMed

    Krueger, Chad A; Wenke, Joseph C; Masini, Brendan D; Stinner, Daniel J

    2012-09-01

    Animal models are commonly used for translational research despite evidence that the methodology of these studies is often inconsistent and substandard. This study describes the characteristics and impact of published research using animal models in the American Journal of Sports Medicine (AJSM). Peer-reviewed articles published in the AJSM between January 1990 and January 2010 using animal models were identified using MEDLINE. The articles were reviewed for funding source, anesthesia used, animal used, study type, study location, outcome measures, number of animals, duration of animal survival, main topic being studied, and positive or negative treatment effect. The impact factor of the studies published between 2005 and 2010 was calculated. Two hundred fifty-seven articles, or 6% (257/4278) of the total publications during the 20-year period, were analyzed. The impact factor increased from 1.83 in 2005 to 3.9 in 2010. The most common animals used were rabbits (24%) and pigs (16%). The anterior cruciate ligament was studied in 34% of the articles, and a pig model was used for 31% of these studies. Eighty-six percent of the studies had a positive treatment effect. This study shows that animal models used in sports medicine research lack uniformity in their methods and suggests that a publication bias may exist for animal research in the sports medicine literature.

  13. Bioenergy harvesting impacts on ecologically important stand structure and habitat characteristics.

    PubMed

    Littlefield, Caitlin E; Keeton, William S

    2012-10-01

    Demand for forest bioenergy fuel is increasing in the northern forest region of eastern North America and beyond, but ecological impacts, particularly on habitat, of bioenergy harvesting remain poorly explored in the peer-reviewed literature. Here, we evaluated the impacts of bioenergy harvests on stand structure, including several characteristics considered important for biodiversity and habitat functions. We collected stand structure data from 35 recent harvests in northern hardwood-conifer forests, pairing harvested areas with unharvested reference areas. Biometrics generated from field data were analyzed using a multi-tiered nonparametric uni- and multivariate statistical approach. In analyses comparing harvested to reference areas, sites that had been whole-tree harvested demonstrated significant differences (relative negative contrasts, P < 0.05) in snag density, large live-tree density, well-decayed downed coarse woody debris volume, and structural diversity index (H) values, while sites that had not been whole-tree harvested did not exhibit significant differences. Classification and regression tree (CART) analyses suggested that the strongest predictors of structural retention, as indicated by downed woody debris volumes and H index, were silvicultural treatment and equipment type rather than the percentage of harvested volume allocated to bioenergy uses. In general, bioenergy harvesting impacts were highly variable across the study sites, suggesting a need for harvesting guidelines aimed at encouraging retention of ecologically important structural attributes.

  14. Flight testing and frequency domain analysis for rotorcraft handling qualities characteristics

    NASA Technical Reports Server (NTRS)

    Ham, Johnnie A.; Gardner, Charles K.; Tischler, Mark B.

    1993-01-01

    A demonstration of frequency domain flight testing techniques and analyses was performed on a U.S. Army OH-58D helicopter in support of the OH-58D Airworthiness and Flight Characteristics Evaluation and the Army's development and ongoing review of Aeronautical Design Standard 33C, Handling Qualities Requirements for Military Rotorcraft. Hover and forward flight (60 knots) tests were conducted in 1 flight hour by Army experimental test pilots. Further processing of the hover data generated a complete database of velocity, angular rate, and acceleration frequency responses to control inputs. A joint effort was then undertaken by the Airworthiness Qualification Test Directorate (AQTD) and the U.S. Army Aeroflightdynamics Directorate (AFDD) to derive handling qualities information from the frequency response database. A significant amount of information could be extracted from the frequency domain database using a variety of approaches. This report documents numerous results that have been obtained from the simple frequency domain tests; in many areas, these results provide more insight into the aircraft dynamics that affect handling qualities than to traditional flight tests. The handling qualities results include ADS-33C bandwidth and phase delay calculations, vibration spectral determinations, transfer function models to examine single axis results, and a six degree of freedom fully coupled state space model. The ability of this model to accurately predict aircraft responses was verified using data from pulse inputs. This report also documents the frequency-sweep flight test technique and data analysis used to support the tests.

  15. Light airplane crash tests at impact velocities of 13 and 27 m/sec

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

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

  16. SRB/FWC water impact: Flexible body loads test

    NASA Technical Reports Server (NTRS)

    1984-01-01

    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.

  17. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    SciTech Connect

    Rudd, A.; Bergey, D.

    2014-02-01

    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.

  18. Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

    SciTech Connect

    Rudd, Armin; Bergey, Daniel

    2014-02-01

    In this project, Building America research team Building Science Corporation tested the effectiveness of ventilation systems 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. This was 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.

  19. Impact of Hypoxia on Drug Resistance and Growth Characteristics of Mycobacterium tuberculosis Clinical Isolates

    PubMed Central

    Bao, Haiyang; Qin, Lianhua; Zhu, Changtai; Chen, Yawen; Hu, Zhongyi

    2016-01-01

    Mycobacterium tuberculosis (MTB) is a specific aerobic bacterium, but can survive under hypoxic conditions, such as those in lung cheese necrosis, granulomas, or macrophages. It is not clear whether the drug sensitivity and growth characteristics of MTB under hypoxic conditions are different from those under aerobic conditions. In this study, we examined the drug resistance and growth characteristics of MTB clinical isolates by a large sample of in vitro drug susceptibility tests, using an automatic growth instrument. Under hypoxic conditions, variance in drug resistance was observed in nearly one-third of the MTB strains and was defined as MTB strains with changed drug sensitivity (MTB-CDS). Among these strains, resistance in a considerable proportion of clinical strains was significantly increased, and some strains emerged as multi-drug resistant. Growth test results revealed a high growth rate and large survival number in macrophages under hypoxia in MTB-CDS. According to the results of fluorescence quantitative PCR, the expression of some genes, including RegX3 (involving RIF resistance), Rv0194 (efflux pump gene), four genes related to transcription regulation (KstR, DosR, Rv0081 and WhiB3) and gene related to translation regulation (DATIN), were upregulated significantly under hypoxic conditions compared to that under aerobic conditions (p < 0.05). Thus, we concluded that some MTB clinical isolates can survive under hypoxic conditions and their resistance could change. As for poor clinical outcomes in patients, based on routine drug susceptibility testing, drug susceptibility tests for tuberculosis under hypoxic conditions should also be recommended. However, the detailed mechanisms of the effect of hypoxia on drug sensitivity and growth characteristics of MTB clinical isolates still requires further study. PMID:27835653

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

    NASA Technical Reports Server (NTRS)

    Nettles, A. T.

    2001-01-01

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

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

    SciTech Connect

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

    2001-05-31

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

  2. Determination of Constitutive Model Constants from Cylinder Impact Tests

    DTIC Science & Technology

    1987-12-01

    HONEYWELL, INC./ARMAMENT SYSTEMS DIVISION) FOR NAVAL SURFACE WARFARE CENTER RESEARCH AND TECHNOLOGY DEPARTMENT DECEMBER 1988 Approved for public release...primary application is for higher strain rates, and the strain rate constant was therefore selected to give better correlation with the higher strain...to that of the test data. The new constants (C and C2) were obtained in conjunction with the previous values of C. and C4, as talen from Reference 2

  3. Small Scale Drop Tower Test for Practice Torpedo Impact Modelling

    DTIC Science & Technology

    2012-06-01

    Table E3. Tensile test results for the aluminium 6061 -T6 model hull plates. 2 coupons were cut with their length parallel to the long side of the...and without stiffeners and aluminium plate without stiffeners. A qualitative comparison of the results for the three model hull forms shows that...stiffeners tend to limit the extent of the dent, that aluminium plate has a greater elastic response than that of both stiffened and unstiffened steel

  4. Point of care testing: The impact of nanotechnology.

    PubMed

    Syedmoradi, Leila; Daneshpour, Maryam; Alvandipour, Mehrdad; Gomez, Frank A; Hajghassem, Hassan; Omidfar, Kobra

    2017-01-15

    Point-of-care (POC) diagnostic devices are integral in the health care system and particularly for the diagnosis and monitoring of diseases. POC testing has a variety of advantages including the ability to provide rapid and accurate results, ease of use, low cost, and little need for specialized equipment. One of the goals of POC testing is the development of a chip-based, miniaturized, portable, and self-containing system that allows for the assay of different analytes in complex samples. To achieve these goals, many researchers have focused on paper-based and printed electrode technologies as the material for fabricating POC diagnostic systems. These technologies are affordable, sensitive, user-friendly, rapid, and scalable for manufacturing. Moreover, the combination such devices with nanomaterials provide a path for the development of highly sensitive and selective biosensors for future generation POC tools. This review article discusses present technologies in on-site or at home POC diagnostic assays implemented in paper-based microfluidic and screen printing devices over the past decade as well as in the near future. In addition, recent advances in the application of nanomaterials such as gold nanoparticles, carbon nanotubes (CNTs), magnetic nanoparticles, and graphene in POC devices will be reviewed. The factors that limit POC testing to become real world products and future directions are also identified.

  5. BRCA1/2 predictive testing and gender: uptake, motivation and psychological characteristics.

    PubMed

    Denayer, L; Boogaerts, A; Philippe, K; Legius, E; Evers-Kiebooms, G

    2009-01-01

    BRCA1/2 predictive testing and gender: Uptake, motivation and psychological characteristics: Data on male uptake of BRCA1/2 predictive testing and psychological characteristics of males in comparison to females are scarce. We investigated gender differences in the cohort tested at the Center for Human Genetics in Leuven during a 10-year period (1998-2007). Males were significantly older than females. Breast cancer related distress (IES) was significantly lower in men and was not associated with BRCA1 or BRCA2. The groups of both males and females were psychologically stronger than average (SCL-90, UCL) and self-selected. Men were unanimously motivated (personal relevance of 12 motives rated on a Likert scale) by concern for their daughters, and significantly more so than women. One third of them (versus 12% women) referred to child-bearing decisions. Considering all unaffected siblings in the family of origin, uptake of predictive testing was significantly higher in females. Moreover, uptake was significantly higher in women belonging to a BRCA2 than to a BRCA1 family. In the descendants of identified carriers, uptake was predicted by gender and age, but not by the parent's gender or by BRCA1 or BRCA2 status.

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

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

    ERIC Educational Resources Information Center

    Schochet, Peter Z.

    2008-01-01

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

  8. Impact of land cover and land use change on runoff characteristics.

    PubMed

    Sajikumar, N; Remya, R S

    2015-09-15

    Change in Land Cover and Land Use (LCLU) influences the runoff characteristics of a drainage basin to a large extent, which in turn, affects the surface and groundwater availability of the area, and hence leads to further change in LCLU. This forms a vicious circle. Hence it becomes essential to assess the effect of change in LCLU on the runoff characteristics of a region in general and of small watershed levels (sub-basin levels) in particular. Such an analysis can effectively be carried out by using watershed simulation models with integrated GIS frame work. SWAT (Soil and Water Analysis Tool) model, being one of the versatile watershed simulation models, is found to be suitable for this purpose as many GIS integration modules are available for this model (e.g. ArcSWAT, MWSWAT). Watershed simulation using SWAT requires the land use and land cover data, soil data and many other features. With the availability of repository of satellite imageries, both from Indian and foreign sources, it becomes possible to use the concurrent local land use and land cover data, thereby enabling more accurate modelling of small watersheds. Such availability will also enable us to assess the effect of LCLU on runoff characteristics and their reverse impact. The current study assesses the effect of land use and land cover on the runoff characteristics of two watersheds in Kerala, India. It also assesses how the change in land use and land cover in the last few decades affected the runoff characteristics of these watersheds. It is seen that the reduction in the forest area amounts to 60% and 32% in the analysed watersheds. However, the changes in the surface runoff for these watersheds are not comparable with the changes in the forest area but are within 20%. Similarly the maximum (peak) value of runoff has increased by an amount of 15% only. The lesser (aforementioned) effect than expected might be due to the fact that forest has been converted to agricultural purpose with major

  9. Gravity Waves characteristics and their impact on turbulent transport above an Antarctic Ice Sheet

    NASA Astrophysics Data System (ADS)

    Cava, Daniela; Giostra, Umberto; Katul, Gabriel

    2016-04-01

    Turbulence within the stable boundary layer (SBL) remains a ubiquitous feature of many geophysical flows, especially over glaciers and ice-sheets. Although numerous studies have investigated various aspects of the boundary layer motion during stable atmospheric conditions, a unified picture of turbulent transport within the SBL remains elusive. In a strongly stratified SBL, turbulence generation is frequently associated with interactions with sub-meso scale motions that are often a combination of gravity waves (GWs) and horizontal modes. While some progress has been made in the inclusion of GW parameterisation within global models, description and parameterisation of the turbulence-wave interaction remain an open question. The discrimination between waves and turbulence is a focal point needed to make progress as these two motions have different properties with regards to heat, moisture and pollutant transport. In fact, the occurrence of GWs can cause significant differences and ambiguities in the interpretation of turbulence statistics and fluxes if not a priori filtered from the analysis. In this work, the characteristics of GW and their impact on turbulent statistics were investigated using wind velocity components and scalars collected above an Antarctic Ice sheet during an Austral Summer. Antarctica is an ideal location for exploring the characteristics of GW because of persistent conditions of strongly stable atmospheric stability in the lower troposphere. Periods dominated by wavy motions have been identified by analysing time series measured by fast response instrumentation. The GWs nature and features have been investigated using Fourier cross-spectral indicators. The detected waves were frequently characterised by variable amplitude and period; moreover, they often produced non-stationarity and large intermittency in turbulent fluctuations that can significantly alter the estimation of turbulence statistics in general and fluxes in particular. A multi

  10. Impact of Pin-by-Pin Thermal-Hydraulic Feedback Modeling on Steady-State Core Characteristics

    SciTech Connect

    Yamamoto, Akio; Ikeno, Tsutomu

    2005-02-15

    In this paper, the effect of a pin-by-pin thermal-hydraulic feedback treatment on the core characteristics at a steady-state condition is investigated using a three-dimensional fine-mesh core calculation code. Currently, advanced nodal codes treat the inside of an assembly as homogeneous, and the temperature distribution inside a node is usually ignored. Namely, the fuel temperature is estimated from the assembly average power density, and the moderator temperature is calculated from the nodewise closed-channel model. However, the validity of a flat temperature distribution inside a node has not yet been investigated, because a three-dimensional pin-by-pin whole-core calculation must be done for comparison. A three-dimensional pin-by-pin nodal-transport code for a pressurized water reactor (PWR) core analysis, SCOPE2, was used in this study since it can directly treat the pin-by-pin feedback effect. A whole-core subchannel analysis code was developed to enhance the thermal-hydraulic capability of SCOPE2. The pin-by-pin feedback models for fuel and moderator temperature were established, and their impact on the core characteristics was investigated in a 3 x 3 multiassembly and the whole PWR core geometries. The calculations showed that modeling of the pin-by-pin temperature distribution revealed a negligible effect on core reactivity and only a slight impact on the radial peaking factor. The difference in the radial peaking factor that is exposed by the pin-by-pin temperature modeling is less than 0.005 in the test calculations.

  11. The Impact of Test Dimensionality, Common-Item Set Format, and Scale Linking Methods on Mixed-Format Test Equating

    ERIC Educational Resources Information Center

    Öztürk-Gübes, Nese; Kelecioglu, Hülya

    2016-01-01

    The purpose of this study was to examine the impact of dimensionality, common-item set format, and different scale linking methods on preserving equity property with mixed-format test equating. Item response theory (IRT) true-score equating (TSE) and IRT observed-score equating (OSE) methods were used under common-item nonequivalent groups design.…

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

    NASA Technical Reports Server (NTRS)

    Peralta, Stephen

    2010-01-01

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

  13. Subsonic static and dynamic stability characteristics of the test technique demonstrator NASP configuration

    NASA Technical Reports Server (NTRS)

    Boyden, Richmond P.; Dress, David A.; Fox, Charles H., Jr.; Huffman, Jarrett K.; Cruz, Christopher I.

    1993-01-01

    The paper describes the procedure used for and the results obtained of wind-tunnel tests of the National Aerospace Plane (NASP) configuration, which were conducted in the NASA Langley Research Center High Speed Tunnel using a blended body NASP configuration designed by the research center. Static and dynamic stability characteristics were measured at Mach numbers 0.3, 0.6, and 0.8. In addition to tests of the baseline configuration, component buildup tests with a canard surface and with a body flap were carried out. Results demonstrated a positive static stability of the baseline configuration, except at the higher angles of attack at Mach 0.8. A good agreement was found between the inphase dynamic parameters and the corresponding static data.

  14. Psychological impact of genetic testing for cancer susceptibility: an update of the literature.

    PubMed

    Meiser, Bettina

    2005-12-01

    This article presents an overview of the rapidly evolving body of literature on the psychological impact of genetic testing for hereditary breast/ovarian cancer susceptibility, hereditary non-polyposis colorectal cancer (HNPCC) and familial adenomatous polyposis (FAP). Uptake of genetic testing for BRCA1/2 and HNPCC-related mutations is more consistently related to psychological factors, rather than sociodemographic variables. Most studies on the psychological impact of genetic testing amongst individuals who have never been affected by cancer demonstrate that non-carriers derive significant psychological benefits from genetic testing, while no adverse effects have been observed amongst carriers. These benefits are more clear-cut for HNPCC, compared to hereditary breast/ovarian cancer, reflecting differences in risk management options. The few studies available on individuals affected with cancer indicate that the impact of genetic testing is mediated and amplified by their former experience of cancer. Future directions and challenges of research in this area are reviewed. In particular, more empirical data are needed on the broader impact of genetic testing on those with inconclusive results or results of uncertain significance. As genetic testing is becoming available for other types of familial cancer, additional investigations will be needed as there is evidence to suggest that the impact of genetic testing may be unique to each type of familial cancer.

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

    NASA Astrophysics Data System (ADS)

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

    2003-04-01

    Large terrestrial impacts produce intense fracturing of the crust and large melt sheets, providing ideal conditions for extensive hydrothermal circulation. In marine settings, such as Chicxulub, there is the potential for downward penetration of cold seawater, heating by the thermal anomaly at the impact site and leaching of metals, prior to buoyancy driven flow back to the surface. There, fluids may undergo venting into the water column. A large proportion of the metals in such vent fluids precipitate close to the site of discharge; however, a proportion of the fluid is dispersed as a hydrothermal plume. Dissolved and particulate materials (in particular manganese and iron oxyhydroxides) can be carried for several hundreds of kilometers, before falling out to form metal-rich sediments. A series of Tertiary core samples has been obtained from the International Continental Drilling Program at Chicxulub (CSDP). These comprise fine-grained cream coloured carbonate sediments with fine laminations. Transmitted light and cathodoluminescence petrography have been used to carry out a preliminary characterization of the samples. Multi-element analysis has also been undertaken by ICP-AES. Samples were reduced to powder and digested using a nitric-perchloric-hydrofluoric acid attack. Rare earth elements (REE) have been analysed by ICP-MS and solutions were prepared using a modified nitric-perchloric-hydrofluoric acid attack. Geochemical analyses have been carried out to test for characteristic signals of hydrothermal input, such as enrichments in Mn, Fe, Cu, Zn, Pb, Mg, Ba, Co, Cr and Ni. The REE are scavenged from seawater onto iron oxide surfaces in the plume; hence anomalous REE concentrations are also indicative of hydrothermal addition. Furthermore, the type of anomaly can differentiate between sediments proximal (+ve Eu) distal (-ve Ce) to the vent site. The stratigraphic extent of any anomalies can be used to constrain the duration of any post-impact circulation. The

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

    PubMed Central

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

    2015-01-01

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

  17. The Impact of Enzyme Characteristics on Corn Stover Fiber Degradation and Acid Production During Ensiled Storage

    NASA Astrophysics Data System (ADS)

    Ren, Haiyu; Richard, Tom L.; Moore, Kenneth J.

    Ensilage can be used to store lignocellulosic biomass before industrial bioprocessing. This study investigated the impacts of seven commerical enzyme mixtures derived from Aspergillus niger, Trichoderma reesei, and T. longibrachiatum. Treatments included three size grades of corn stover, two enzyme levels (1.67 and 5 IU/g dry matter based on hemicellulase), and various ratios of cellulase to hemicellulase (C ∶ H). The highest C ∶ H ratio tested, 2.38, derived from T. reesei, resulted in the most effective fermentation, with lactic acid as the dominant product. Enzymatic activity during storage may complement industrial pretreatment; creating synergies that could reduce total bioconversion costs.

  18. The impact of enzyme characteristics on corn stover fiber degradation and acid production during ensiled storage.

    PubMed

    Ren, Haiyu; Richard, Tom L; Moore, Kenneth J

    2007-04-01

    Ensilage can be used to store lignocellulosic biomass before industrial bioprocessing. This study investigated the impacts of seven commercial enzyme mixtures derived from Aspergillus niger, Trichoderma reesei, and T. longibrachiatum. Treatments included three size grades of corn stover, two enzyme levels (1.67 and 5 IU/g dry matter based on hemicellulase), and various ratios of cellulase to hemicellulase (C:H). The highest C:H ratio tested, 2.38, derived from T. reesei, resulted in the most effective fermentation, with lactic acid as the dominant product. Enzymatic activity during storage may complement industrial pretreatment; creating synergies that could reduce total bioconversion costs.

  19. Test and analysis of the infrared characteristic of the plume-smoke

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaolong; Zhang, Guang; Chen, Dapeng; Dong, Yanbing

    2015-04-01

    The plume-smoke is one of the main infrared characteristic signal sources of the engine. In this paper, the infrared signal characteristic of a small test engine's plume-smoke is studied. We conduct a quantitative observation of some specific points in the movement path of the plume-smoke by the MW and LW infrared thermal imager. Through the analysis of the smokeless and smoke infrared sequential images, we can get the infrared radiation and the transmission characteristics of the plume-smoke and their variation law with time. Experiments show that there exists a critical temperature of the plume-smoke; the radiation of background can increase when the temperature of the plume-smoke is higher than the critical temperature. On the contrary, the radiation of background decreases when the temperature of the plume-smoke is lower than the critical temperature. In this paper, the research provides a reference for further study on the infrared characteristic of the plume-smoke.

  20. Response of an Impact Test Apparatus for Fall Protective Headgear Testing Using a Hybrid-III Head/Neck Assembly

    PubMed Central

    Caccese, V.; Ferguson, J.; Lloyd, J.; Edgecomb, M.; Seidi, M.; Hajiaghamemar, M.

    2017-01-01

    A test method based upon a Hybrid-III head and neck assembly that includes measurement of both linear and angular acceleration is investigated for potential use in impact testing of protective headgear. The test apparatus is based upon a twin wire drop test system modified with the head/neck assembly and associated flyarm components. This study represents a preliminary assessment of the test apparatus for use in the development of protective headgear designed to prevent injury due to falls. By including angular acceleration in the test protocol it becomes possible to assess and intentionally reduce this component of acceleration. Comparisons of standard and reduced durometer necks, various anvils, front, rear, and side drop orientations, and response data on performance of the apparatus are provided. Injury measures summarized for an unprotected drop include maximum linear and angular acceleration, head injury criteria (HIC), rotational injury criteria (RIC), and power rotational head injury criteria (PRHIC). Coefficient of variation for multiple drops ranged from 0.4 to 6.7% for linear acceleration. Angular acceleration recorded in a side drop orientation resulted in highest coefficient of variation of 16.3%. The drop test apparatus results in a reasonably repeatable test method that has potential to be used in studies of headgear designed to reduce head impact injury. PMID:28216804

  1. The impact of nursing characteristics and the work environment on perceptions of communication.

    PubMed

    Tschannen, Dana; Lee, Eunjoo

    2012-01-01

    Failure to communicate openly and accurately to members of the healthcare team can result in medical error. The purpose of this study was to explore the impact of nursing characteristics and environmental values on communication in the acute care setting. Nurses (n = 135) on four medical-surgical units in two hospitals completed a survey asking nurses' perceptions of communication, work environment, and nursing demographics. LPNs perceived significantly higher levels of open communication with nurses than did RNs (P = .042). RNs noted higher levels of accuracy of communication among nurses than did LPNs (P < .001). Higher experience levels resulted in greater perceptions of open communication. Only environmental values (e.g., trust, respect) were a significant predictor of both openness and accuracy of communication. These findings suggest understanding the environment (e.g., presence or absence of trust, respect, status equity, and time availability) is a foundational step that must occur before implementing any strategies aimed at improving communication.

  2. The impact of climate variability and seasonal characteristics on flood occurrence in north-eastern Italy

    NASA Astrophysics Data System (ADS)

    Zoccatelli, Davide; Borga, Marco

    2013-04-01

    The aim of this work is to analyse the impact of climate variability and seasonal characteristics in the long-term regimes of extreme precipitation and floods in catchments located in north-eastern Italy. We use seasonality indices, climate variability indexes (NOA and WMO) and atmospheric circulation patterns to isolate the sources of variability on flood-inducing processes. This is supported by cluster analyses to identify areas of similar flood processes, both in terms of precipitation forcing and catchment processes. The results allow to isolate regions of similar flood generation processes, effects of soil moisture seasonality due to evaporation and effects of soil moisture seasonality due to snow melt. It is argued that the synoptic approach proposed here is valuable in both flood analysis and flood estimation.

  3. Supersonic dynamic stability characteristics of the test technique demonstrator NASP configuration

    NASA Technical Reports Server (NTRS)

    Dress, David A.; Boyden, Richmond P.; Cruz, Christopher I.

    1992-01-01

    Wind tunnel tests of a National Aero-Space Plane (NASP) configuration were conducted in both test sections of the Langley Unitary Plan Wind Tunnel. The model used is a Langley designed blended body NASP configuration. Dynamic stability characteristics were measured on this configuration at Mach numbers of 2.0, 2.5, 3.5, and 4.5. In addition to tests of the baseline configuration, component buildup tests were conducted. The test results show that the baseline configuration generally has positive damping about all three axes with only isolated exceptions. In addition, there was generally good agreement between the in-pulse dynamic parameters and the corresponding static data which were measured during another series of tests in the Unitary Plan Wind Tunnel. Also included are comparisons of the experimental damping parameters with results from the engineering predictive code APAS (Aerodynamic Preliminary Analysis System). These comparisons show good agreement at low angles of attack; however, the comparisons are generally not as good at the higher angles of attack.

  4. Patient-initiated second opinions: systematic review of characteristics and impact on diagnosis, treatment, and satisfaction.

    PubMed

    Payne, Velma L; Singh, Hardeep; Meyer, Ashley N D; Levy, Lewis; Harrison, David; Graber, Mark L

    2014-05-01

    The impact of second opinions on diagnosis in radiology and pathology is well documented; however, the value of patient-initiated second opinions for diagnosis and treatment in general medical practice is unknown. We conducted a systematic review of patient-initiated second opinions to assess their impact on clinical outcomes and patient satisfaction and to determine characteristics and motivating factors of patients who seek a second opinion. We searched PubMed, EMBASE, Cochrane, and Academic OneFile databases using Medical Subject Headings (MeSH) indexes and keyword searches. Search terms included referral and consultation, patient-initiated, patient preference, patient participation, second opinion, second review, and diagnosis. Multiple reviewers screened abstracts and articles to determine eligibility and extract data. We assessed risk of bias using the Cochrane Risk of Bias Tool and rated study quality using Cochrane's GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach. We screened 1342 abstracts and reviewed full text of 41 articles, identifying 7 articles that reported clinical agreement data and 10 that discussed patient characteristics, motivation, and satisfaction. We found that a second opinion typically confirms the original diagnosis or treatment regimen but that 90% of patients with poorly defined conditions remain undiagnosed. However, 10% to 62% of second opinions yield a major change in the diagnosis, treatment, or prognosis. A larger fraction of patients receive different advice on treatment than on diagnosis. Factors motivating a second opinion include diagnosis or treatment confirmation, dissatisfaction with a consultation, desire for more information, persistent symptoms, or treatment complications. Patients generally believed that second opinions were valuable. Second opinions can result in diagnostic and treatment differences. The literature on patient-initiated second opinions is limited, and the accuracy of

  5. Antipsychotic-induced sensitization and tolerance: Behavioral characteristics, developmental impacts, and neurobiological mechanisms

    PubMed Central

    Li, Ming

    2016-01-01

    Antipsychotic sensitization and tolerance refer to the increased and decreased drug effects due to past drug use, respectively. Both effects reflect the long-term impacts of antipsychotic treatment on the brain and result from the brain’s adaptive response to the foreign property of the drug. In this review, clinical evidence of the behavioral aspect of antipsychotic sensitization and tolerance is selectively reviewed, followed by an overview of preclinical literature that examines these behavioral characteristics and the related pharmacological and nonpharmacological factors. Next, recent work on the developmental impacts of adolescent antipsychotic sensitization and tolerance is presented and recent research that delineates the neurobiological mechanisms of antipsychotic sensitization and tolerance is summarized. A theoretical framework based on “drug learning and memory” principles is proposed to account for the phenomena of antipsychotic sensitization and tolerance. It is maintained that antipsychotic sensitization and tolerance follow basic principles of learning or acquisition (“induction”) and memory (“expression”). The induction and expression of both effects reflect the consequences of associative and nonassociative processing and are strongly influenced by various pharmacological, environmental, and behavioral factors. Drug-induced neuroplasticity, such as functional changes of striatal dopamine D2 and prefrontal serotonin (5-HT)2A receptors and their mediated signaling pathways, in principle, is responsible for antipsychotic sensitization and tolerance. Understanding the behavioral characteristics and neurobiological underpinnings of antipsychotic sensitization and tolerance has greatly enhanced our understanding of mechanisms of antipsychotic action, and may have important implications for future drug discovery and clinical practice. PMID:27371498

  6. Prevalence and characteristics of migraine in medical students and its impact on their daily activities

    PubMed Central

    Menon, Bindu; Kinnera, Neeharika

    2013-01-01

    Background: Migraine is a common neurological disorder with significant impact on quality of life. The aim of this study was to investigate the prevalence and characteristics of migraine headaches in medical students, to measure its impact on their life, and to assess their knowledge about the ailment. Information about lifestyle variables was also collected. Materials and Methods: All medical students who confirmed of having headache for more than 1 year formed the study group. Students filled a detailed questionnaire focusing on demographics, pain characteristics, accompanying factors, triggers, and family history of migraine. Lifestyle variables were enquired and migraine associated disability was assessed by MIDAS (Migraine Disability Assessment). The diagnosis of migraine was made according to the International Headache Society criteria. Results are expressed in n = numbers and percentage. Results: Sixty-eight percent of medical students had headache. The prevalence of migraine in the whole cohort was 28%; however, of the headache group, migraine constituted 42%. There was a female preponderance. One-fourth of the students had weekly or daily attacks with 31% students reporting increase in their headache intensity and frequency. Forty-four percent of students had severe headaches. Dizziness, allodynia, and neck stiffness were reported as accompanying symptoms. Trigger factors were identified in 99% students, predominant of which were poor sleep hygiene, environmental changes, head movements, and mental stress. Only 4% of students did regular exercise. Twenty-seven percent of students reported self-medication use of analgesics. One-fourth of the students had migraine-associated disability but only 6% realized that they had migraine. Conclusion: Our study found a high prevalence of headache with migraine in medical students. The students’ awareness of the disease was very low with one-fourth of the students resorting to self-medication. Our study identified

  7. Impact of Energy Gain and Subsystem Characteristics on Fusion Propulsion Performance

    NASA Technical Reports Server (NTRS)

    Chakrabarti, S.; Schmidt, G. R.

    2001-01-01

    Rapid transport of large payloads and human crews throughout the solar system requires propulsion systems having very high specific impulse (I(sub sp) > 10(exp 4) to 10(exp 5) s). It also calls for systems with extremely low mass-power ratios (alpha < 10(exp -1) kg/kW). Such low alpha are beyond the reach of conventional power-limited propulsion, but may be attainable with fusion and other nuclear concepts that produce energy within the propellant. The magnitude of energy gain must be large enough to sustain the nuclear process while still providing a high jet power relative to the massive energy-intensive subsystems associated with these concepts. This paper evaluates the impact of energy gain and subsystem characteristics on alpha. Central to the analysis are general parameters that embody the essential features of any 'gain-limited' propulsion power balance. Results show that the gains required to achieve alpha = 10(exp -1) kg/kW with foreseeable technology range from approximately 100 to over 2000, which is three to five orders of magnitude greater than current fusion state of the arL Sensitivity analyses point to the parameters exerting the most influence for either: (1) lowering a and improving mission performance or (2) relaxing gain requirements and reducing demands on the fusion process. The greatest impact comes from reducing mass and increasing efficiency of the thruster and subsystems downstream of the fusion process. High relative gain, through enhanced fusion processes or more efficient drivers and processors, is also desirable. There is a benefit in improving driver and subsystem characteristics upstream of the fusion process, but it diminishes at relative gains > 100.

  8. Reverberant Acoustic Testing and Direct Field Acoustic Testing Acoustic Standing Waves and their Impact on Structural Responses

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    The aerospace industry has been using two methods of acoustic testing to qualify flight hardware: (1) Reverberant Acoustic Test (RAT), (2) Direct Field Acoustic Test (DFAT). The acoustic field obtained by RAT is generally understood and assumed to be diffuse, expect below Schroeder cut-of frequencies. DFAT method of testing has some distinct advantages over RAT, however the acoustic field characteristics can be strongly affected by test setup such as the speaker layouts, number and location of control microphones and control schemes. In this paper the following are discussed based on DEMO tests performed at APL and JPL: (1) Acoustic wave interference patterns and acoustic standing waves, (2) The structural responses in RAT and DFAT.

  9. Exploring the impact of forcing error characteristics on physically based snow simulations within a global sensitivity analysis framework

    NASA Astrophysics Data System (ADS)

    Raleigh, M. S.; Lundquist, J. D.; Clark, M. P.

    2015-07-01

    Physically based models provide insights into key hydrologic processes but are associated with uncertainties due to deficiencies in forcing data, model parameters, and model structure. Forcing uncertainty is enhanced in snow-affected catchments, where weather stations are scarce and prone to measurement errors, and meteorological variables exhibit high variability. Hence, there is limited understanding of how forcing error characteristics affect simulations of cold region hydrology and which error characteristics are most important. Here we employ global sensitivity analysis to explore how (1) different error types (i.e., bias, random errors), (2) different error probability distributions, and (3) different error magnitudes influence physically based simulations of four snow variables (snow water equivalent, ablation rates, snow disappearance, and sublimation). We use the Sobol' global sensitivity analysis, which is typically used for model parameters but adapted here for testing model sensitivity to coexisting errors in all forcings. We quantify the Utah Energy Balance model's sensitivity to forcing errors with 1 840 000 Monte Carlo simulations across four sites and five different scenarios. Model outputs were (1) consistently more sensitive to forcing biases than random errors, (2) generally less sensitive to forcing error distributions, and (3) critically sensitive to different forcings depending on the relative magnitude of errors. For typical error magnitudes found in areas with drifting snow, precipitation bias was the most important factor for snow water equivalent, ablation rates, and snow disappearance timing, but other forcings had a more dominant impact when precipitation uncertainty was due solely to gauge undercatch. Additionally, the relative importance of forcing errors depended on the model output of interest. Sensitivity analysis can reveal which forcing error characteristics matter most for hydrologic modeling.

  10. Modeling analysis of secondary inorganic aerosols over China: pollution characteristics, and meteorological and dust impacts.

    PubMed

    Fu, Xiao; Wang, Shuxiao; Chang, Xing; Cai, Siyi; Xing, Jia; Hao, Jiming

    2016-10-26

    Secondary inorganic aerosols (SIA) are the predominant components of fine particulate matter (PM2.5) and have significant impacts on air quality, human health, and climate change. In this study, the Community Multiscale Air Quality modeling system (CMAQ) was modified to incorporate SO2 heterogeneous reactions on the surface of dust particles. The revised model was then used to simulate the spatiotemporal characteristics of SIA over China and analyze the impacts of meteorological factors and dust on SIA formation. Including the effects of dust improved model performance for the simulation of SIA concentrations, particularly for sulfate. The simulated annual SIA concentration in China was approximately 10.1 μg/m(3) on domain average, with strong seasonal variation: highest in winter and lowest in summer. High SIA concentrations were concentrated in developed regions with high precursor emissions, such as the North China Plain, Yangtze River Delta, Sichuan Basin, and Pearl River Delta. Strong correlations between meteorological factors and SIA pollution levels suggested that heterogeneous reactions under high humidity played an important role on SIA formation, particularly during severe haze pollution periods. Acting as surfaces for heterogeneous reactions, dust particles significantly affected sulfate formation, suggesting the importance of reducing dust emissions for controlling SIA and PM2.5 pollution.

  11. Modeling analysis of secondary inorganic aerosols over China: pollution characteristics, and meteorological and dust impacts

    NASA Astrophysics Data System (ADS)

    Fu, Xiao; Wang, Shuxiao; Chang, Xing; Cai, Siyi; Xing, Jia; Hao, Jiming

    2016-10-01

    Secondary inorganic aerosols (SIA) are the predominant components of fine particulate matter (PM2.5) and have significant impacts on air quality, human health, and climate change. In this study, the Community Multiscale Air Quality modeling system (CMAQ) was modified to incorporate SO2 heterogeneous reactions on the surface of dust particles. The revised model was then used to simulate the spatiotemporal characteristics of SIA over China and analyze the impacts of meteorological factors and dust on SIA formation. Including the effects of dust improved model performance for the simulation of SIA concentrations, particularly for sulfate. The simulated annual SIA concentration in China was approximately 10.1 μg/m3 on domain average, with strong seasonal variation: highest in winter and lowest in summer. High SIA concentrations were concentrated in developed regions with high precursor emissions, such as the North China Plain, Yangtze River Delta, Sichuan Basin, and Pearl River Delta. Strong correlations between meteorological factors and SIA pollution levels suggested that heterogeneous reactions under high humidity played an important role on SIA formation, particularly during severe haze pollution periods. Acting as surfaces for heterogeneous reactions, dust particles significantly affected sulfate formation, suggesting the importance of reducing dust emissions for controlling SIA and PM2.5 pollution.

  12. Large Impact Basins on Mercury: Global Distribution, Characteristics, and Modification History from MESSENGER Orbital Data

    NASA Technical Reports Server (NTRS)

    Fassett, Caleb I.; Head, James W.; Baker, David M. H.; Zuber, Maria T.; Neumann, Gregory A.; Solomon, Sean C.; Klimczak, Christian; Strom, Robert G.; Chapman, Clark R.; Prockter, Louise M.; Phillips, Roger J.; Oberst, Juergen; Preusker, Frank

    2012-01-01

    The formation of large impact basins (diameter D greater than or equal to 300 km) was an important process in the early evolution of Mercury and influenced the planet's topography, stratigraphy, and crustal structure. We catalog and characterize this basin population on Mercury from global observations by the MESSENGER spacecraft, and we use the new data to evaluate basins suggested on the basis of the Mariner 10 flybys. Forty-two certain or probable impact basins are recognized a few additional basins that may have been degraded to the point of ambiguity are plausible on the basis of new data but are classified as uncertain. The spatial density of large basins (D greater than or equal to 500 km) on Mercury is lower than that on the Moon. Morphological characteristics of basins on Mercury suggest that on average they are more degraded than lunar basins. These observations are consistent with more efficient modification, degradation, and obliteration of the largest basins on Mercury than on the Moon. This distinction may be a result of differences in the basin formation process (producing fewer rings), greater relaxation of topography after basin formation (subduing relief), and/or higher rates of volcanism during the period of heavy bombardment on Mercury compared to the Moon (burying basin rings and interiors).

  13. Modeling analysis of secondary inorganic aerosols over China: pollution characteristics, and meteorological and dust impacts

    PubMed Central

    Fu, Xiao; Wang, Shuxiao; Chang, Xing; Cai, Siyi; Xing, Jia; Hao, Jiming

    2016-01-01

    Secondary inorganic aerosols (SIA) are the predominant components of fine particulate matter (PM2.5) and have significant impacts on air quality, human health, and climate change. In this study, the Community Multiscale Air Quality modeling system (CMAQ) was modified to incorporate SO2 heterogeneous reactions on the surface of dust particles. The revised model was then used to simulate the spatiotemporal characteristics of SIA over China and analyze the impacts of meteorological factors and dust on SIA formation. Including the effects of dust improved model performance for the simulation of SIA concentrations, particularly for sulfate. The simulated annual SIA concentration in China was approximately 10.1 μg/m3 on domain average, with strong seasonal variation: highest in winter and lowest in summer. High SIA concentrations were concentrated in developed regions with high precursor emissions, such as the North China Plain, Yangtze River Delta, Sichuan Basin, and Pearl River Delta. Strong correlations between meteorological factors and SIA pollution levels suggested that heterogeneous reactions under high humidity played an important role on SIA formation, particularly during severe haze pollution periods. Acting as surfaces for heterogeneous reactions, dust particles significantly affected sulfate formation, suggesting the importance of reducing dust emissions for controlling SIA and PM2.5 pollution. PMID:27782166

  14. Tracking Particulate Organic Matter Characteristics in Major Arctic Rivers: Indicators of Watershed-Scale Climate Impacts

    NASA Astrophysics Data System (ADS)

    McClelland, J. W.; Griffin, C. G.; Holmes, R. M.; Peterson, B. J.; Raymond, P. A.; Spencer, R. G.; Striegl, R. G.; Tank, S. E.

    2015-12-01

    Six large rivers, including the Yukon and Mackenzie in North America and the Yenisey, Ob', Lena, and Kolyma in Eurasia, drain the majority of the watershed area surrounding the Arctic Ocean. Parallel sampling programs were initiated at downstream locations on these rivers in 2003 to improve estimates of fluvial export and track large-scale perturbations associated with climate change. Over a decade later, synthesis of water chemistry data from these ongoing sampling efforts provides an unprecedented opportunity to 1) examine similarities and differences among the major Arctic rivers, and 2) think critically about how changes in various water chemistry parameters may or may not inform us about climate change impacts. River-borne organic matter characteristics may be particularly telling because mass flux values and composition/source indicators vary with hydrology and permafrost coverage. However, separating climate impacts that occur within river corridors from those that occur beyond them may be difficult, especially when considering changes in particulate organic matter (POM) loads. Data on suspended POM yields, C:N ratios, stable isotope ratios, and radiocarbon content in the major Arctic rivers show marked spatial, seasonal, and interannual variability that is helpful for thinking about how climate change effects may manifest in the future, but it will be challenging to separate changes in POM related to bank erosion and suspension/deposition of in situ sediment stocks from changes in POM that may be linked to processes such as permafrost thaw occurring across the broader landscape.

  15. Non Q wave infarction: exercise test characteristics, coronary anatomy, and prognosis.

    PubMed Central

    Fox, J P; Beattie, J M; Salih, M S; Davies, M K; Littler, W A; Murray, R G

    1990-01-01

    The exercise test characteristics, coronary anatomy, and prognosis of patients discharged after non Q wave myocardial infarction were compared with those in whom Q wave infarction occurred. Of the 339 patients studied, all of whom were less than or equal to 70 years, 87 (26%) had had a non Q wave infarction. There were no significant differences in the exercise test characteristics between the two groups, and in those 149 patients in whom angiography was performed triple vessel disease was present in 36/114 (32%) of the Q wave group and 9/35 (26%) of the non Q wave group. The infarct related artery was more often patent in the non Q wave group (27/35 (77%] than in the Q wave group (53/114 (46%]. The one year mortality and the reinfarction and angina rates were similar in the two groups and the exercise test remained a good discriminator for predicting patients at risk of future cardiac events in both groups. In view of the similar outcome and severity of coronary disease in those aged less than or equal to 70 with non Q wave infarcts, the distinction between Q and non Q wave infarction need not influence management decisions in patients after myocardial infarction. PMID:2328166

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

    PubMed

    Crozier, S; Robertson, N; Dale, M

    2015-02-01

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

  17. Characteristics of small tropical cumulus clouds and their impact on the environment

    SciTech Connect

    Benner, T.C.; Curry, J.A.

    1998-11-01

    This study uses a number of data sets (Moderate Resolution Imaging Spectroradiometer (MODIS) Airborne Simulator data, space shuttle photography, Radiation Measurement System data, aircraft data, and shipboard soundings) to investigate the characteristics of small tropical cumulus clouds and their impact on their environment. The goal is to uncover useful information with application to radiative transfer simulation and satellite remote sensing. In fields of small cumulus clouds, size distributions are found to decrease in number with increasing diameter according to a double power law relation, often with a clear break diameter. Fractal dimensions corresponding to the horizontal area and perimeter of the clouds are greater for the larger clouds than for the smaller clouds, with the same break diameter as the size distributions, meaning that the larger clouds have more ragged perimeters. These two results suggest a characteristic horizontal length scale dividing larger and smaller boundary layer cumuli. Spatial distributions show a clear tendency toward clustering. Smaller cumuli appear to grow upward more quickly with increasing horizontal size than do larger cumuli. Albedo is found to increase with greater cloud fraction and higher solar zenith angle. Even sparse fields of small cumulus cause significant shortwave forcing at the ocean surface. Simulation suggests that small cumulus may introduce significant errors into sea surface temperature retrievals and that such clouds can be difficult to remove with operational cloud-filtering schemes. Clouds smaller than about 1 km in diameter are not seen to precipitate. {copyright} 1998 American Geophysical Union

  18. Impact of low-energy photons on the characteristics of prompt fission γ -ray spectra

    NASA Astrophysics Data System (ADS)

    Oberstedt, A.; Billnert, R.; Hambsch, F.-J.; Oberstedt, S.

    2015-07-01

    In this paper we report on a new study of prompt γ -rays from the spontaneous fission of 252Cf . Photons were measured in coincidence with fission fragments by employing four different lanthanide halide scintillation detectors. Together with results from a previous work of ours, we determined characteristic parameters with high precision, such as the average γ -ray multiplicity ν¯γ=(8.29 ±0.13 ), the average energy per photon ɛγ=(0.80 ±0.02 ) MeV, and the total γ -ray energy release per fission Eγ ,tot=(6.65 ±0.10 ) MeV. The excellent agreement between the individual results obtained in all six measurements proves the good repeatability of the applied experimental technique. The impact of low-energy photons, i.e., below 500 keV, on prompt fission γ -ray spectra characteristics has been investigated as well by comparing our results with those taken with the DANCE detector system, which appears to suffer from absorption effects in the low-energy region. Correction factors for this effect were estimated, giving results comparable to ours as well as to historical ones. From this we demonstrate that the different techniques of determining the average γ -ray multiplicity, either from a properly measured and normalized spectrum or a measured multiplicity distribution, give equivalent and consistent results.

  19. Multi-Terrain Impact Testing and Simulation of a Composite Energy Absorbing Fuselage Section

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Lyle, Karen H.; Sparks, Chad E.; Sareen, Ashish K.

    2004-01-01

    Comparisons of the impact performance of a 5-ft diameter crashworthy composite fuselage section were investigated for hard surface, soft soil, and water impacts. The fuselage concept, which was originally designed for impacts onto a hard surface only, consisted of a stiff upper cabin, load bearing floor, and an energy absorbing subfloor. Vertical drop tests were performed at 25-ft/s onto concrete, soft-soil, and water at NASA Langley Research Center. Comparisons of the peak acceleration values, pulse durations, and onset rates were evaluated for each test at specific locations on the fuselage. In addition to comparisons of the experimental results, dynamic finite element models were developed to simulate each impact condition. Once validated, these models can be used to evaluate the dynamic behavior of subfloor components for improved crash protection for hard surface, soft soil, and water impacts.

  20. Multi-Terrain Impact Testing and Simulation of a Composite Energy Absorbing Fuselage Section

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

    Comparisons of the impact performance of a 5-ft diameter crashworthy composite fuselage section were investigated for hard surface, soft soil, and water impacts. The fuselage concept, which was originally designed for impacts onto a hard surface only, consisted of a stiff upper cabin, load bearing floor, and an energy absorbing subfloor. Vertical drop tests were performed at 25-ft/s onto concrete, soft-soil, and water at NASA Langley Research Center. Comparisons of the peak acceleration values, pulse durations, and onset rates were evaluated for each test at specific locations on the fuselage. In addition to comparisons of the experimental results, dynamic finite element models were developed to simulate each impact condition. Once validated, these models can be used to evaluate the dynamic behavior of subfloor components for improved crash protection for hard surface, soft soil, and water impacts.

  1. Impact of corrosion test container material in molten fluorides

    SciTech Connect

    Olson, Luke C.; Fuentes, Roderick E.; Martinez-Rodriguez, Michael J.; Ambrosek, James W.; Sridharan, Kumar; Anderson, Mark H.; Garcia-Diaz, Brenda L.; Gray, Joshua; Allen, Todd R.

    2015-10-15

    The effects of crucible material choice on alloy corrosion rates in immersion tests in molten LiF–NaF–KF (46.5–11.5-42 mol. %) salt held at 850 °C for 500 hrs are described. Four crucible materials were studied. Molten salt exposures of Incoloy-800H in graphite, Ni, Incoloy-800H, and pyrolytic boron nitride (PyBN) crucibles all led to weight-loss in the Incoloy-800H coupons. Alloy weight loss was ~30 times higher in the graphite and Ni crucibles in comparison to the Incoloy-800H and PyBN crucibles. It is hypothesized galvanic coupling between the alloy coupons and crucible materials contributed to the higher corrosion rates. Alloy salt immersion in graphite and Ni crucibles had similar weight-loss hypothesized to occur due to the rate limiting out diffusion of Cr in the alloys to the surface where it reacts with and dissolves into the molten salt, followed by the reduction of Cr from solution at the molten salt and graphite/Ni interfaces. As a result, both the graphite and the Ni crucibles provided sinks for the Cr, in the formation of a Ni–Cr alloy in the case of the Ni crucible, and Cr carbide in the case of the graphite crucible.

  2. Impact of corrosion test container material in molten fluorides

    DOE PAGES

    Olson, Luke C.; Fuentes, Roderick E.; Martinez-Rodriguez, Michael J.; ...

    2015-10-15

    The effects of crucible material choice on alloy corrosion rates in immersion tests in molten LiF–NaF–KF (46.5–11.5-42 mol. %) salt held at 850 °C for 500 hrs are described. Four crucible materials were studied. Molten salt exposures of Incoloy-800H in graphite, Ni, Incoloy-800H, and pyrolytic boron nitride (PyBN) crucibles all led to weight-loss in the Incoloy-800H coupons. Alloy weight loss was ~30 times higher in the graphite and Ni crucibles in comparison to the Incoloy-800H and PyBN crucibles. It is hypothesized galvanic coupling between the alloy coupons and crucible materials contributed to the higher corrosion rates. Alloy salt immersion inmore » graphite and Ni crucibles had similar weight-loss hypothesized to occur due to the rate limiting out diffusion of Cr in the alloys to the surface where it reacts with and dissolves into the molten salt, followed by the reduction of Cr from solution at the molten salt and graphite/Ni interfaces. As a result, both the graphite and the Ni crucibles provided sinks for the Cr, in the formation of a Ni–Cr alloy in the case of the Ni crucible, and Cr carbide in the case of the graphite crucible.« less

  3. Impact of Acetylsalicylic Acid on the Clinicopathological Characteristics and Prognosis of Patients with Invasive Breast Cancer

    PubMed Central

    Sendur, Mehmet A.N.; Aksoy, Sercan; Ozdemir, Nuriye Y.; Zengin, Nurullah; Altundag, Kadri

    2014-01-01

    Summary Background The impact of acetylsalicylic acid (ASA) on the clinicopathological characteristics of breast cancer has not yet been elucidated in detail; we therefore aimed to investigate the effects of ASA on the clinicopathological characteristics of patients with breast cancer. Patients and Methods Patients diagnosed with breast cancer were retrospectively analyzed. Breast cancer patients who were taking ASA at the time of breast cancer diagnosis were enrolled as ASA users (n = 84); matching patients with the same age who were not taking ASA were included as control group (n = 890). Results The median age was 56 (range 34–82) years in both groups. ASA users had a significantly lower incidence of grade II–III tumors compared to non-users (P = 0.02). The other clinicopathological characteristics and treatment histories were similar in both groups. In patients using ASA, the disease-free survival (DFS) rate was 97.3%, 89.4%, and 79.9% and in non-users it was 94.1%, 81.8%, and 70.9% in the 1rst, 3rd, and 5th year, respectively (P = 0.01). In aspirin users, the overall survival rate was 95.0%, 90.6%, and 87.6% and in non-users it was 98.1%, 91.2%, and 85.5% in the 1rst, 3rd, and 5th year, respectively (P = 0.50). Conclusion Using ASA at the time of breast cancer diagnosis was associated with significantly improved DFS in breast cancer patients. PMID:25404885

  4. How Small the Number of Test Items Can Be for the Basis of Estimating the Operating Characteristics of the Discrete Responses to Unknown Test Items.

    ERIC Educational Resources Information Center

    Samejima, Fumiko; Changas, Paul S.

    The methods and approaches for estimating the operating characteristics of the discrete item responses without assuming any mathematical form have been developed and expanded. It has been made possible that, even if the test information function of a given test is not constant for the interval of ability of interest, it is used as the Old Test.…

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

    PubMed

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

    2014-01-01

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

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

    PubMed

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

    2013-01-01

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

  7. The Testing Divide: New Research on the Intended and Unintended Impact of High-Stakes Testing.

    ERIC Educational Resources Information Center

    Amrein, Audrey L.; Berliner, David C.

    2003-01-01

    Found, based on data from 28 states, that there is scant evidence to support the proposition that high-stakes tests, including high-stakes high school graduation exams, increase student achievement. Also found that adoption of high-stakes testing policies leads to increased dropout rates, decreased graduation rates, and higher rates of younger…

  8. Psychological impact of genetic testing for Huntington's disease: an update of the literature.

    PubMed

    Meiser, B; Dunn, S

    2000-11-01

    Genetic testing has been available for Huntington's disease for longer than any other adult onset genetic disorder. The discovery of the genetic mutation causing Huntington's disease made possible the use of predictive testing to identify currently unaffected carriers. Concerns have been raised that predictive testing may lead to an increase in deaths by suicide among identified carriers, and these concerns set in motion research to assess the psychological impact of predictive testing for Huntington's disease. This review article provides an overview of the literature and draws implications for clinical practice. About 10%-20% of people at risk request testing when approached by registries or testing centres. Most of the evidence suggests that non-carriers and carriers differ significantly in terms of short term, but not long term, general psychological distress. Adjustment to results was found to depend more on psychological adjustment before testing than the testing result itself. Although risk factors for psychological sequelae have been identified, few adverse events have been described and no obvious contraindications for testing people at risk have been identified. The psychological impact of testing may depend on whether testing was based on linkage analysis or mutation detection. Cohorts enrolled in mutation detection programmes have higher levels of depression before and after testing, compared with people who sought genetic testing when linkage analysis was available. There is evidence that people who choose to be tested are psychologically selected for a favourable response to testing. The impact of testing on people in settings where less intensive counselling protocols and eligibility criteria are used is unknown, and genetic testing is therefore best offered as part of comprehensive specialist counselling.

  9. Impact of Panel Gene Testing for Hereditary Breast and Ovarian Cancer on Patients.

    PubMed

    Lumish, Heidi S; Steinfeld, Hallie; Koval, Carrie; Russo, Donna; Levinson, Elana; Wynn, Julia; Duong, James; Chung, Wendy K

    2017-03-29

    Recent advances in next generation sequencing have enabled panel gene testing, or simultaneous testing for mutations in multiple genes for a clinical condition. With more extensive and widespread genetic testing, there will be increased detection of genes with moderate penetrance without established clinical guidelines and of variants of uncertain significance (VUS), or genetic variants unknown to either be disease-causing or benign. This study surveyed 232 patients who underwent genetic counseling for hereditary breast and ovarian cancer to examine the impact of panel gene testing on psychological outcomes, patient understanding, and utilization of genetic information. The survey used standardized instruments including the Impact of Event Scale (IES), Multidimensional Impact of Cancer Risk Assessment (MICRA), Satisfaction with Decision Instrument (SWD), Ambiguity Tolerance Scale (AT-20), genetics knowledge, and utilization of genetic test results. Study results suggested that unaffected individuals with a family history of breast or ovarian cancer who received positive results were most significantly impacted by intrusive thoughts, avoidance, and distress. However, scores were also modestly elevated among unaffected patients with a family history of breast and ovarian cancer who received VUS, highlighting the impact of ambiguous results that are frequent among patients undergoing genetic testing with large panels of genes. Potential risk factors for increased genetic testing-specific distress in this study included younger age, black or African American race, Hispanic origin, lower education level, and lower genetic knowledge and highlight the need for developing strategies to provide effective counseling and education to these communities, particularly when genetic testing utilizes gene panels that more commonly return VUS. More detailed pre-test education and counseling may help patients appreciate the probability of various types of test results and how results

  10. The Impact of Mandated Statewide Testing on Teachers' Classroom Assessment and Instructional Practices.

    ERIC Educational Resources Information Center

    McMillan, James H.; Myran, Steve; Workman, Daryl

    The impact of the new Virginia statewide Standards of Learning (SOL) testing program on classroom instructional and assessment practices was studied through surveys before and after implementation of the testing program. The sample represented responses from 570 secondary school teachers (of mathematics, social studies, English, and science) and…

  11. An Exploration of the Impact of Accountability Testing on Teaching in Urban Elementary Classrooms

    ERIC Educational Resources Information Center

    Bisland, Beverly Milner

    2015-01-01

    This study explores accountability testing in the elementary schools of New York City with particular emphasis on the impact of a statewide social studies test on the value given to social studies instruction in comparison to other subjects. The attitudes of a group of elementary teachers are examined. Some of the teachers taught all subjects in…

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

    ERIC Educational Resources Information Center

    Polesel, John; Rice, Suzanne; Dulfer, Nicole

    2014-01-01

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

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

    ERIC Educational Resources Information Center

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

    2005-01-01

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

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

    ERIC Educational Resources Information Center

    Airola, Denise Tobin

    2011-01-01

    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…

  15. The Impact of Time-Series Diagnostic Tests on the Writing Ability of Iranian EFL Learners

    ERIC Educational Resources Information Center

    Atashgahi, Bahareh Molazem

    2014-01-01

    This study aimed to show whether administering a battery of time-series diagnostic tests (screening) has any impact on Iranian EFL learners' writing ability. The study was conducted on the intermediate EFL learners at Islamic Azad University North Tehran branch. The researcher administered a homogenizing test in order to exclude the exceptional…

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

    ERIC Educational Resources Information Center

    Schochet, Peter Z.

    2009-01-01

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

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

    ERIC Educational Resources Information Center

    De Corte, Wilfried; Lievens, Filip

    2005-01-01

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

  18. Characteristics of candidate sites selected for onsite fuel cell power plant testing

    NASA Astrophysics Data System (ADS)

    Racine, W. C.; Ferraro, V. D.; Woods, R. R.

    A portion of the Onsite Fuel Cell Program involves field testing forty-nine, 40-kW onsite fuel cell power plants. This paper describes the energy characteristics of 82 different sites that have been selected as potential field test locations. The 82 sites include multi-family residential, commercial and light industrial buildings that represent 26 market segments throughout the United States and Japan. Each one of the 82 sites has been instrumented with a standard data acquisition system to obtain hourly thermal and electrical energy consumption data. This energy data will help determine each site's compatibility with a 40-kW fuel cell power plant, and will provide an extensive data base which may be useful in other energy studies.

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

    NASA Technical Reports Server (NTRS)

    Barbee, Brent W.; Hernandez, Sonia

    2012-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

    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.

  1. Health Behaviors and Standardized Test Scores: The Impact of School Health Climate on Performance

    ERIC Educational Resources Information Center

    Gunter, Whitney D.; Daly, Kevin

    2013-01-01

    Research has found that many characteristics are related to performance on standardized tests. Many of these are not necessarily "academic" attributes. One area of this research is on the connection between physical health or lifestyles and test performance. The research that exists in this area is often disconnected with each other and…

  2. Accurate diagnosis of myalgic encephalomyelitis and chronic fatigue syndrome based upon objective test methods for characteristic symptoms

    PubMed Central

    Twisk, Frank NM

    2015-01-01

    Although myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS) are considered to be synonymous, the definitional criteria for ME and CFS define two distinct, partially overlapping, clinical entities. ME, whether defined by the original criteria or by the recently proposed criteria, is not equivalent to CFS, let alone a severe variant of incapacitating chronic fatigue. Distinctive features of ME are: muscle weakness and easy muscle fatigability, cognitive impairment, circulatory deficits, a marked variability of the symptoms in presence and severity, but above all, post-exertional “malaise”: a (delayed) prolonged aggravation of symptoms after a minor exertion. In contrast, CFS is primarily defined by (unexplained) chronic fatigue, which should be accompanied by four out of a list of 8 symptoms, e.g., headaches. Due to the subjective nature of several symptoms of ME and CFS, researchers and clinicians have questioned the physiological origin of these symptoms and qualified ME and CFS as functional somatic syndromes. However, various characteristic symptoms, e.g., post-exertional “malaise” and muscle weakness, can be assessed objectively using well-accepted methods, e.g., cardiopulmonary exercise tests and cognitive tests. The objective measures acquired by these methods should be used to accurately diagnose patients, to evaluate the severity and impact of the illness objectively and to assess the positive and negative effects of proposed therapies impartially. PMID:26140274

  3. Accurate diagnosis of myalgic encephalomyelitis and chronic fatigue syndrome based upon objective test methods for characteristic symptoms.

    PubMed

    Twisk, Frank Nm

    2015-06-26

    Although myalgic encephalomyelitis (ME) and chronic fatigue syndrome (CFS) are considered to be synonymous, the definitional criteria for ME and CFS define two distinct, partially overlapping, clinical entities. ME, whether defined by the original criteria or by the recently proposed criteria, is not equivalent to CFS, let alone a severe variant of incapacitating chronic fatigue. Distinctive features of ME are: muscle weakness and easy muscle fatigability, cognitive impairment, circulatory deficits, a marked variability of the symptoms in presence and severity, but above all, post-exertional "malaise": a (delayed) prolonged aggravation of symptoms after a minor exertion. In contrast, CFS is primarily defined by (unexplained) chronic fatigue, which should be accompanied by four out of a list of 8 symptoms, e.g., headaches. Due to the subjective nature of several symptoms of ME and CFS, researchers and clinicians have questioned the physiological origin of these symptoms and qualified ME and CFS as functional somatic syndromes. However, various characteristic symptoms, e.g., post-exertional "malaise" and muscle weakness, can be assessed objectively using well-accepted methods, e.g., cardiopulmonary exercise tests and cognitive tests. The objective measures acquired by these methods should be used to accurately diagnose patients, to evaluate the severity and impact of the illness objectively and to assess the positive and negative effects of proposed therapies impartially.

  4. Impact testing of the H1224A shipping/storage container

    SciTech Connect

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

    1994-05-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  6. Investigating the Relationship between Test-Taker Background Characteristics and Test Performance in a Heterogeneous English-as-a-Second-Language (ESL) Test Population: A Factor Analytic Approach. Research Report. ETS RR-15-25

    ERIC Educational Resources Information Center

    Manna, Venessa F.; Yoo, Hanwook

    2015-01-01

    This study examined the heterogeneity in the English-as-a-second-language (ESL) test population by modeling the relationship between test-taker background characteristics and test performance as measured by the "TOEFL iBT"® using a confirmatory factor analysis (CFA) with covariate approach. The background characteristics studied…

  7. The impact of a national poverty reduction program on the characteristics of sex partners among Kenyan adolescents.

    PubMed

    Rosenberg, Molly; Pettifor, Audrey; Thirumurthy, Harsha; Halpern, Carolyn Tucker; Handa, Sudhanshu

    2014-02-01

    Cash transfer programs have the potential to prevent the spread of HIV, particularly among adolescents. One mechanism through which these programs may work is by influencing the characteristics of the people adolescents choose as sex partners. We examined the four-year impact of a Kenyan cash transfer program on partner age, partner enrollment in school, and transactional sex-based relationships among 684 adolescents. We found no significant impact of the program on partner characteristics overall, though estimates varied widely by gender, age, schooling, and economic status. Results highlight the importance of context in exploring the potential HIV preventive effects of cash transfers.

  8. Preliminary Tests in the NACA Tank to Investigate the Fundamental Characteristics of Hydrofoils

    NASA Technical Reports Server (NTRS)

    Ward, Kenneth E.; Land, Norman S.

    1940-01-01

    This preliminary investigation was made to study the hydrodynamic properties and general behavior of simple hydrofoils. Six 5- by 30-inch plain, rectangular hydrofoils were tested in the NACA tank at various speeds, angles of attack and depths below the water surface. Two of the hydrofoils had sections representing the sections of commonly used airfoils, one had a section similar to one developed Guidoni for use with hydrofoil-equipped seaplane floats, and three had sections designed to have constant chordwise pressure distributions at given values of the lift coefficient for the purpose of delaying the speed at which cavitation begins. The experimental results are presented as curves of the lift and drag coefficients plotted against speed for the various angles of attack and depths for which the hydrofoils were tested. A number of derived curves are included for the purpose of better comparing the characteristics of the hydrofoils and to show the effects of depth. Several representative photographs show the development of cavitation on the the upper surface of the hydrofoils. The results indicate that properly designed hydrofoil sections will have excellent characteristics and that the speed at which cavitation occurs may be delayed to an appreciable extent by the use of suitable sections.

  9. Adsorption characteristics of siloxanes in landfill gas by the adsorption equilibrium test

    SciTech Connect

    Nam, Sangchul; Namkoong, Wan; Kang, Jeong-Hee; Park, Jin-Kyu; Lee, Namhoon

    2013-10-15

    Highlights: • Equilibrium test was attempted to evaluate adsorption characteristics of siloxane. • L2 had higher removal efficiency in carbon compared to noncarbon adsorbents. • Total adsorption capacity of siloxane was 300 mg/g by coal activated carbon. • Adsorption characteristics rely on size of siloxane molecule and adsorbent pore. • Conversion of siloxane was caused by adsorption of noncarbon adsorbents. - Abstract: Due to the increase in energy cost by constantly high oil prices and the obligation to reduce greenhouse effect gases, landfill gas is frequently used as an alternative energy source for producing heat and electricity. Most of landfill gas utility facilities, however, are experiencing problems controlling siloxanes from landfill gas as their catalytic oxidizers are becoming fouled by silicon dioxide dust. To evaluate adsorption characteristics of siloxanes, an adsorption equilibrium test was conducted and parameters in the Freundlich and Langmuir isotherms were analyzed. Coconut activated carbon (CA1), coal activated carbon (CA2), impregnated activated carbon (CA3), silicagel (NCA1), and activated alumina (NCA2) were used for the adsorption of the mixed siloxane which contained hexamethyldisiloxane (L2), octamethylcyclotetrasiloxane (D4), and decamethylcyclopentasiloxane (D5). L2 had higher removal efficiency in noncarbon adsorbents compared to carbon adsorbents. The application of Langmuir and Freundlich adsorption isotherm demonstrated that coconut based CA1 and CA3 provided higher adsorption capacity on L2. And CA2 and NCA1 provided higher adsorption capacity on D4 and D5. Based on the experimental results, L2, D4, and D5 were converted by adsorption and desorption in noncarbon adsorbents. Adsorption affinity of siloxane is considered to be affect by the pore size distribution of the adsorbents and by the molecular size of each siloxane.

  10. A seal test facility for the measurement of isotropic and anisotropic linear rotordynamic characteristics

    NASA Technical Reports Server (NTRS)

    Adams, M. L.; Yang, T.; Pace, S. E.

    1989-01-01

    A new seal test facility for measuring high-pressure seal rotor-dynamic characteristics has recently been made operational at Case Western Reserve University (CWRU). This work is being sponsored by the Electric Power Research Institute (EPRI). The fundamental concept embodied in this test apparatus is a double-spool-shaft spindle which permits independent control over the spin speed and the frequency of an adjustable circular vibration orbit for both forward and backward whirl. Also, the static eccentricity between the rotating and non-rotating test seal parts is easily adjustable to desired values. By accurately measuring both dynamic radial displacement and dynamic radial force signals, over a wide range of circular orbit frequency, one is able to solve for the full linear-anisotropic model's 12 coefficients rather than the 6 coefficients of the more restrictive isotropic linear model. Of course, one may also impose the isotropic assumption in reducing test data, thereby providing a valid qualification of which seal configurations are well represented by the isotropic model and which are not. In fact, as argued in reference (1), the requirement for maintaining a symmetric total system mass matrix means that the resulting isotropic model needs 5 coefficients and the anisotropic model needs 11 coefficients.

  11. Test study on the performance of shielding configuration with stuffed layer under hypervelocity impact

    NASA Astrophysics Data System (ADS)

    Ke, Fa-wei; Huang, Jie; Wen, Xue-zhong; Ma, Zhao-xia; Liu, Sen

    2016-10-01

    In order to study the cracking and intercepting mechanism of stuffed layer configuration on the debris cloud and to develop stuffed layer configuration with better performance, the hypervelocity impact tests on shielding configurations with stuffed layer were carried out. Firstly, the hypervelocity impact tests on the shielding configuration with stuffed layer of 3 layer ceramic fibre and 3 layer aramid fibre were finished, the study results showed that the debris cloud generated by the aluminum sphere impacting bumper at the velocity of about 6.2 km/s would be racked and intercepted by the stuffed layer configuration efficiently when the ceramic fibre layers and aramid fibre layers were jointed together, however, the shielding performance would be declined when the ceramic fibre layers and aramid fibre layers were divided by some distance. The mechanism of stuffed layer racking and intercepting the debris cloud was analyzed according to the above test results. Secondly, based on the mechanism of the stuffed layer cracking and intercepint debirs cloud the hypervelocity impact tests on the following three stuffed layer structures with the equivalent areal density to the 1 mm-thick aluminum plate were also carried out to compare their performance of cracking and intercepting debris cloud. The mechanisms of stuffed layer racking and intercepting the debris cloud were validated by the test result. Thirdly, the influence of the stuffed layer position on the shielding performance was studied by the test, too. The test results would provide reference for the design of better performance shielding configuration with stuffed layer.

  12. Impact Testing and Analysis of Composites for Aircraft Engine Fan Cases

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

    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.

  13. Psychosocial impact of repeat HIV-negative testing: a follow-up study.

    PubMed

    Ryder, Karen; Haubrich, Dennis J; Callà, Domenico; Myers, Ted; Burchell, Ann N; Calzavara, Liviana

    2005-12-01

    Continued sexual risk behavior following repeatedly testing HIV-negative in the Polaris HIV Seroconversion Study (Ontario, Canada) led to this follow-up study which identifies the impact of repeat negative testing among 64 men and women. Repeat HIV-negative testing frequently results in confusion as to what constitutes risk and occasionally to thoughts of HIV immunity. Narrative accounts include beliefs that monogamy constitutes safety from HIV, that psychosocial factors other than repeatedly testing negative leads to risk, and that sexual risk reduction is unsustainable. In conclusion, the repeat negative test experience for some neither clarifies risk behavior nor reinforces sustained risk reduction.

  14. Crash Testing and Simulation of a Cessna 172 Aircraft: Pitch Down Impact Onto Soft Soil

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Jackson, Karen E.

    2016-01-01

    During the summer of 2015, NASA Langley Research Center conducted three full-scale crash tests of Cessna 172 (C-172) aircraft at the NASA Langley Landing and Impact Research (LandIR) Facility. The first test represented a flare-to-stall emergency or hard landing onto a rigid surface. The second test, which is the focus of this paper, represented a controlled-flight-into-terrain (CFIT) with a nose-down pitch attitude of the aircraft, which impacted onto soft soil. The third test, also conducted onto soil, represented a CFIT with a nose-up pitch attitude of the aircraft, which resulted in a tail strike condition. These three crash tests were performed for the purpose of evaluating the performance of Emergency Locator Transmitters (ELTs) and to generate impact test data for model validation. LS-DYNA finite element models were generated to simulate the three test conditions. This paper describes the model development and presents test-analysis comparisons of acceleration and velocity time-histories, as well as a comparison of the time sequence of events for Test 2 onto soft soil.

  15. A systematic review of perceived risks, psychological and behavioral impacts of genetic testing.

    PubMed

    Heshka, Jodi T; Palleschi, Crystal; Howley, Heather; Wilson, Brenda; Wells, Philip S

    2008-01-01

    Genetic testing may enable early disease detection, targeted surveillance, and result in effective prevention strategies. Knowledge of genetic risk may also enable behavioral change. However, the impact of carrier status from the psychological, behavior, and perceived risk perspectives is not well understood. We conducted a systematic review to summarize the available literature on these elements. An extensive literature review was performed to identify studies that measured the perceived risk, psychological, and/or behavioral impacts of genetic testing on individuals. The search was not limited to specific diseases but excluded the impacts of testing for single gene disorders. A total of 35 articles and 30 studies were included. The studies evaluated hereditary nonpolyposis colorectal carcinoma, hereditary breast and ovarian cancer, and Alzheimer disease. For affective outcomes, the majority of the studies reported negative effects on carriers but these were short-lived. For behavioral outcomes, an increase in screening behavior of varying rates was demonstrated in carriers but the change in behaviors was less than expected. With respect to perceived risk, there were generally no differences between carriers and noncarriers by 12 months after genetic testing and over time risk perception decreased. Overall, predispositional genetic testing has no significant impact on psychological outcomes, little effect on behavior, and did not change perceived risk. It seems as though better patient education strategies are required. Our data would suggest better knowledge among carriers would not have significant psychological impacts and therefore, it is worth pursuing improved educational strategies.

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

    NASA Technical Reports Server (NTRS)

    Lyons, Frankel

    2013-01-01

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

  17. [The Predictive Ability of Entrance Testing and a Survey of Socio-Economic Characteristics at Lake Land College.

    ERIC Educational Resources Information Center

    Lach, Ivan J.

    The predictive ability of required tests as to grade point averages (GPA) and a survey of students' socio-economic characteristics are reported on in two separate studies from Lake Land College (Illinois). In the first paper a comparative study of required reading and mathematics tests and the American College Test (ACT) as to their ability to…

  18. Oblique impact sensitivity of explosives: The skid test the snatch friction sensitivity test. Quarterly report, April--June 1964

    SciTech Connect

    Akst, I.B.; Washburn, B.M.; Rigdon, J.K.

    1997-09-01

    The oblique impact sensitivity of UK-UK-simulated HMX in 85 to 90% formulation with Viton is not enough lower, if any, to encourage richer formulations or change to Bridgewater processes for this reason alone. Fifty-pound cyclotol 75/25 hemispheres gave moderate reactions (No. 4) as low as 3.5 foot (14{degrees}); lower tests have not been performed yet. {open_quotes}Reduced-H.E.{close_quotes} pieces of PBX 9404, 2, 3, 4, and 5 inches thick, respectively, were tested at 1.75 foot (14{degrees}) resulting in a 6 reaction for the 5 inches thick piece while the remaining three pieces gave 0 reactions.

  19. The impact of marine aerosols on atmospheric characteristics over ocean surface in frontal zones

    NASA Astrophysics Data System (ADS)

    Pavlova, Hanna; Palamarchuk, Iuliia; Ruban, Igor; Ivanov, Sergiy

    2015-04-01

    Ocean-derived aerosols are particles produced from the ocean surface and remaining suspended in the atmosphere during a certain period of time. Aerosols act as climate forcers both directly (by scattering and absorbing solar radiation) and indirectly (by affecting cloud microphysics as cloud condensation nuclei). To evaluate the degree of marine aerosols impact on weather conditions the numerical experiments with the HARMONIE model were conducted with the model domain covering area over the North Atlantic. The results showed that marine aerosols have a significant impact on characteristics of the atmosphere (such as air temperature, specific humidity, precipitation, and vertical velocity) over the ocean surface. The most significant differences occur along the frontal zones with high gradients at all vertical levels in the atmosphere for all variables. Change in radiative fluxes leads to changes in temperature of the atmosphere. These anomalies appear as mesoscale cells of opposite signs alternating each other. It can be assumed that they are formed as a result of a chain of factors. Thus, the absorption and scattering of solar radiation in the upper troposphere during daytime, increasing of moisture content and subsequent increase in thermal inertia of the air, and enhanced greenhouse effect at nighttime are acting in different directions on formation of vertical structure and convection conditions. This leads to a strengthening/weakening of the updrafts and compensatory movements, and eventually to the changes in processes of precipitation formation. Thus, the simulation of weather conditions in frontal zones over the ocean requires considering the effect of the marine aerosols presence.

  20. The effects of low impact development on urban flooding under different rainfall characteristics.

    PubMed

    Qin, Hua-peng; Li, Zhuo-xi; Fu, Guangtao

    2013-11-15

    Low impact development (LID) is generally regarded as a more sustainable solution for urban stormwater management than conventional urban drainage systems. However, its effects on urban flooding at a scale of urban drainage systems have not been fully understood particularly when different rainfall characteristics are considered. In this paper, using an urbanizing catchment in China as a case study, the effects of three LID techniques (swale, permeable pavement and green roof) on urban flooding are analyzed and compared with the conventional drainage system design. A range of storm events with different rainfall amounts, durations and locations of peak intensity are considered for holistic assessment of the LID techniques. The effects are measured by the total flood volume reduction during a storm event compared to the conventional drainage system design. The results obtained indicate that all three LID scenarios are more effective in flood reduction during heavier and shorter storm events. Their performance, however, varies significantly according to the location of peak intensity. That is, swales perform best during a storm event with an early peak, permeable pavements perform best with a middle peak, and green roofs perform best with a late peak, respectively. The trends of flood reduction can be explained using a newly proposed water balance method, i.e., by comparing the effective storage depth of the LID designs with the accumulative rainfall amounts at the beginning and end of flooding in the conventional drainage system. This paper provides an insight into the performance of LID designs under different rainfall characteristics, which is essential for effective urban flood management.

  1. [Impact of wind-water alternate erosion on the characteristics of sediment particles].

    PubMed

    Tuo, Deng-Feng; Xu, Ming-Xiang; Ma, Xin-Xin; Zheng, Shi-Qing

    2014-02-01

    Wind and water are the two dominant erosion agents that caused soil and water losses in the wind-water alternate erosion region on the Loess Plateau. It is meaningful to study the impact of wind-water alternate erosion on the characteristics of soil particles for understanding the response of soil quality and environment to erosion. Through wind tunnel combined rainfall simulation, this paper studied the characteristics of the erosive sediment particles under the effect of wind-water alternate erosion. The results showed that the particles of 0-1 cm soil were coarsened by wind erosion at the wind speeds of 11 and 14 m x s(-1) compared with no wind erosion. Soil fine particles (< 0.01 mm) decreased by 9.8%-10.8%, and coarse particles (> 0.05 mm) increased by 16.8%-20.8%. The physical property of surface soil was changed by the wind erosion, which, in turn, caused an increase in finer particles content in the sediment. Compared with no wind erosion, fine particles (< 0.01 mm) in sediment under the water-wind alternate erosion increased by 2.7%-18.9% , and coarse particles (> 0.05 mm) decreased by 3.7%-9.3%. However, the changing trend of erosive sediment particles after the wind erosion at wind speeds of 11 and 14 m x s(-1) was different along with the rainfall intensity and duration. The erosive sediment particles at the rainfall intensities of 60, 80, 100 mm x h(-1) changed to greater extents than at the 150 mm x h(-1) rainfall intensity with longer than 15 min runoff flowing.

  2. A high loading overland flow system: Impacts on soil characteristics, grass constituents, yields and nutrient removal.

    PubMed

    Wen, C G; Chen, T H; Hsu, F H; Lu, C H; Lin, J B; Chang, C H; Chang, S P; Lee, C S

    2007-04-01

    The objectives of this paper are to determine effects of different grass species and their harvests on pollutant removal, elucidate impacts on soil characteristics and grass constituents, observe grass yield and quantify nutrient uptake by vegetation in an overland flow system (OLFS). Polluted creek water was applied to eight channels in the OLFS, which were planted with Paragrass, Nilegrass, Cattail, and Vetiver, with each two channels being randomly planted with a given grass species. The grass in one channel was harvested while that in the other channel was not. At a high rate of 27.8 m d(-1) hydraulic loading, the removal efficiencies of conventional pollutants such as BOD, COD, suspended solids (SS), and total coliforms in wastewater are not affected by the type of the grasses species, but those of nitrogen and phosphorus are affected by different species. Overall average removal efficiencies of BOD, COD, SS, ammonia, total nitrogen, total phosphorus and total coliforms through the OLFS are 42%, 48%, 78%, 47%, 40%, 33% and 89%, respectively. The concentration of nitrate, however, increases due to nitrification. Soil characteristics in OLFS have been changed significantly; specific conductivity, organic matter, exchangeable magnesium, extractable copper and zinc in soils all increase with time while pHs decrease. During the winter season, there is a significant accumulation of nitrate in grass with the subsequent reduction during the active growing season (Spring). The contents of nitrate and phosphorus in grass tissue are higher than those of grass in general pastureland, probably due to nutrient luxury uptake by grass. The overall grass yield, growth rate and nutrient uptake are quantified and implication of such high rate OLFS discussed.

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

    NASA Technical Reports Server (NTRS)

    1990-01-01

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

  4. Impact of device geometry on the imaging characteristics of an intravascular photoacoustic catheter.

    PubMed

    Wu, Min; Jansen, Krista; Springeling, Geert; van der Steen, Antonius F W; van Soest, Gijs

    2014-12-01

    A basic requirement for intravascular photoacoustic (IVPA) imaging catheters is that the delivery of light lies within the ultrasonic field of view. Size and manufacturing constraints favor probe designs with offset optical and acoustic beams. This noncollinear dual beam arrangement leads to a curved PA point spread function (PSF). In this work, we characterize the three-dimensional shape of the PSF for IVPA imaging in clear and optically scattering media. We show that the product of the two beam profiles can accurately model the measured peak response in clear and scattering media. We discuss the impact of the PSF shape and its relation to probe construction. We test the imaging capability of the catheter on a phantom and a human artery ex vivo.

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

    ERIC Educational Resources Information Center

    Hafner, Anne L.

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

  6. Influence of stress concentrator shape and testing temperature on impact fracture regularities of pipeline steel

    NASA Astrophysics Data System (ADS)

    Vlasov, I. V.; Panin, S. V.; Maruschak, P. O.; Moiseenko, D. D.; Berto, F.

    2017-02-01

    The structure and impact toughness of the pipeline 17Mn1Si steel have been studied. The main attention was paid to the analysis of various conditions of stress concentration under dynamic loadings. The process of strain localization with increasing stress state stiffness at the tip of the concentrator with decreasing testing temperature was investigated. Impact loading diagrams for specimens with various stress concentrator shapes were registered and analyzed.

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

    PubMed

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

    2014-11-01

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

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

    SciTech Connect

    Martino, C. J.

    2013-08-13

    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.

  9. Ductile Damage Prediction in Taylor Impact Cylinder Test Using CDM Approach

    NASA Astrophysics Data System (ADS)

    Ruggiero, A.; Bonora, N.

    2004-07-01

    Taylor cylinder impact test has been initially proposed as a potential testing technique to measure dynamic effect on material yield strength. Today, this technique represents an interesting benchmark case for constitutive and damage model performance verification. In this study, an extensive numerical investigation, using both finite element code and Lagrangian hydro-code, has been performed on standard Taylor impact cylinder configuration and Rod-on-Rod (ROR) test in OFHC and OFE copper. Here, material strength has been modeled using Johnson and Cook formulation which accounts both strain rate and temperature material sensibility. Ductile damage has been modeled using an advanced continuum damage mechanics model, as proposed by Bonora, which accounts for stress triaxiality effects on ductility, stress history at material point and where only a limited number of parameters is required. For both the test configuration investigated, both final calculated post test shape and damage pattern have been compared with experimental data available in literature.

  10. Guidelines for conducting impact tests on shipping packages for radioactive material

    SciTech Connect

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

    1995-09-01

    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.

  11. Laser induced projectile impact test (LIPIT): A micron-scale ballistic test for high-strain rate mechanical study of nano-structures

    NASA Astrophysics Data System (ADS)

    Lee, Jae-Hwang; Veysset, David; Nelson, Keith; Thomas, Edwin

    2012-02-01

    We present a method to apply a highly localized deformation at a high-strain-rate for the study of mechanical characteristics of micro- and nano-structures. In the technique, Laser Induced Projectile Impact Test (LIPIT), micro-projectiles (solid silica spheres of 3.7μm diameter) are accelerated to a supersonic speed (up to 4 km/s) in air by a micro-explosion created by laser ablation of polystyrene and impact a sample target. The velocity information of the micro-projectiles is explicitly determined by two consecutive high-speed images during the flight of the projectiles. For demonstration, a glassy-rubbery nanocomposite consisting of a periodic self-assembled stack of 20 nm thick layers of polystyrene and polydimethylsiloxane blocks (PS-b-PDMS) is tested by LIPIT at the extremely high-strain rate of 10^8 s-1. The polymer nanocomposite demonstrates new orientation dependent deformation and failure mechanisms including a surprising order to disorder transition fluidization, and the energy absorbing ability of a layered nanocomposite through plastic deformation leading to a melting of the layered structure.

  12. Responses of the Q6/Q6s ATD Positioned in Booster Seats in the Far-Side Seat Location of Side Impact Passenger Car and Sled Tests.

    PubMed

    Tylko, Suzanne; Bohman, Katarina; Bussières, Alain

    2015-11-01

    Passenger car side impact crash tests and sled tests were conducted to investigate the influence of booster seats, near-side occupant characteristics and vehicle interiors on the responses of the Q6/Q6s child ATD positioned in the rear, far-side seating location. Data from nine side impact sled tests simulating a EuroNCAP AEMD barrier test were analyzed with data obtained from 44 side impact crash tests. The crash tests included: FMVSS 214 and IIHS MDB, moving car-to-stationary car and moving car-to-moving car. A Q6 or prototype Q6s ATD was seated on the far-side, using a variety of low and high back booster seats. Head and chest responses were recorded and ATD motions were tracked with high-speed videos. The vehicle lateral accelerations resulting from MDB tests were characterized by a much earlier and more rapid rise to peak than in tests where the bullet was another car. The near-side seating position was occupied by a Hybrid III 10-year-old ATD in the sled tests, and a rear or front facing child restraint or a 5th percentile side impact ATD in the crash tests. Head impacts occurred more frequently in vehicles where a forward facing child restraint was present behind the driver seat for both the low and high back booster seats. Pretensioners were found to reduce lateral head displacements in all sled test configurations but the greatest reduction in lateral excursion was obtained with a high back booster seat secured with LATCH and tested in combination with pretensioners.

  13. Mechanical impact tests of materials in oxygen effects of contamination. [Teflon, stainless steel, and aluminum

    NASA Technical Reports Server (NTRS)

    Ordin, P. M.

    1980-01-01

    The effect of contaminants on the mechanical impact sensitivity of Teflon, stainless steel, and aluminum in a high-pressure oxygen environment was investigated. Uncontaminated Teflon did not ignite under the test conditions. The liquid contaminants - cutting oil, motor lubricating oil, and toolmaker dye - caused Teflon to ignite. Raising the temperature lowered the impact energy required for ignition. Stainless steel was insensitive to ignition under the test conditions with the contaminants used. Aluminum appeared to react without contaminants under certain test conditions; however, contamination with cutting oil, motor lubricating oil, and toolmakers dye increased the sensitivity of aluminum to mechanical impact. The grit contaminants silicon dioxide and copper powder did not conclusively affect the sensitivity of aluminum.

  14. Railgun Application for High Energy Impact Testing of Nano-Reinforced Kevlar-Based Composite Materials

    NASA Astrophysics Data System (ADS)

    Micheli, D.; Vricella, A.; Pastore, R.; Morles, R. B.; Marchetti, M.

    2013-08-01

    An advanced electromagnetic accelerator, called railgun, has been assembled and tuned in order to perform high energy impact test on layered structures. Different types of layered composite materials have been manufactured and characterized in terms of energy absorbing capability upon impact of metallic bullets fired at high velocity. The composite materials under testing are manufactured by integrating several layers of Kevlar fabric and carbon fiber ply within a polymeric matrix reinforced by carbon nanotubes at 1% of weight percentage. The experimental results show that the railgun-device is a good candidate to perform impact testing of materials in the space debris energy range, and that carbon nanotubes may enhance, when suitably coupled to the composite's matrix, the excellent antiballistic properties of the Kevlar fabrics.

  15. Comparison of Hybrid III child test dummies to pediatric PMHS in blunt thoracic impact response.

    PubMed

    Parent, D P; Crandall, J R; Bolton, J R; Bass, C R; Ouyang, J; Lau, S H

    2010-08-01

    The limited availability of pediatric biomechanical impact response data presents a significant challenge to the development of child dummies. In the absence of these data, the development of the current generation of child dummies has been driven by scaling of the biomechanical response requirements of the existing adult test dummies. Recently published pediatric blunt thoracic impact response data provide a unique opportunity to evaluate the efficacy of these scaling methodologies. However, the published data include several processing anomalies and nonphysical features. These features are corrected by minimizing instrumentation and processing error to improve the fidelity of the individual force-deflection responses. Using these data, biomechanical impact response corridors are calculated for a 3-year-old child and a 6-year-old child. These calculated corridors differ from both the originally published postmortem human subject (PMHS) corridors and the impact response requirements of the current child dummies. Furthermore, the response of the Hybrid III 3-year-old test dummy in the same impact condition shows a similar deflection but a significantly higher force than the 3-year-old corridor. The response of the Hybrid III 6-year-old dummy, on the other hand, correlates well with the calculated 6-year-old corridor. The newly developed 3-year-old and 6-year-old blunt thoracic impact response corridors can be used to define data-driven impact response requirements as an alternative to scaling-driven requirements.

  16. Fabrication and characteristics of a test magnet from HTS Bi-2223 silver-clad tapes

    SciTech Connect

    Haldar, P.; Hoehn, J.G. Jr.; Motowidlo, L.R.; Iwasa, Y.

    1993-07-01

    Critical currents of powder-in-tube processed silver-clad Bi-2223 short tape samples and coils have been measured at liquid nitrogen (77 K), liquid neon (27 K) and liquid helium (4.2 K) temperatures. The short samples have been characterized in fields up to 20 T and indicate a large anisotropy at 27 K with resistive behavior above 15 T in the worst field direction. A test magnet consisting of pancake coils generated magnetic fields greater than 1.0, 0.7 and 0.11 T at 4.2 K, 27 K and 77 K respectively. The ctest magnet generates significant self-fields in background fields up to 14.5 T at 4.2 K and 27 K. Optimization of thermo-mechanical process parameters have yielded J{sub c}`s in the superconducting core > 4.0 {times} 10{sup 4} A/cm{sup 2} at 77 K, zero field and > 2.0 {times} 10{sup 5} A/cm{sup 2} at 4.2 K, zero field for short tape samples. Long lengths (>30 m) of silver-clad tape superconductors have also been fabricated and tested to carry significant amounts of current (J{sub c} core > 10,000 A/cm{sup 2}) at 77 K. Overall J{sub c} of short and long samples and characteristics of the test magnet are reported.

  17. Hydraulic characteristics of low-impact development practices in northeastern Ohio, 2008–2010

    USGS Publications Warehouse

    Darner, Robert A.; Dumouchelle, Denise H.

    2011-01-01

    Low-impact development (LID) is an approach to managing stormwater as near to its source as possible; this is accomplished by minimizing impervious surfaces and promoting more natural infiltration and evapotranspiration than is typically associated with developed areas. Two newly constructed LID sites in northeastern Ohio were studied to document their hydraulic characteristics. A roadside best-management practice (BMP) was constructed by replacing about 1,400 linear feet of existing ditches with a bioswale/rain garden BMP consisting of a grassed swale interspersed with rain-garden/overflow structures. The site was monitored in 2008, 2009, and 2010. Although some overflows occurred, numerous precipitation events exceeding the 0.75-inch design storm did not result in overflows. A second study site consists of an 8,200-square-foot parking lot made of a pervious pavers and a rain garden that receives runoff from the roof of a nearby commercial building. A comparison of data from 2009 and 2010 indicates that the median runoff volume in 2010 decreased relative to 2009. The centroid lag times (time difference between centroid of precipitation and centroid of flow) decreased in 2010, most likely due to more intense, shorter duration precipitation events and maturation of the rain garden. Additional data could help quantify the relation between meteorological variables and BMP efficiency.

  18. SPAD-based leaf nitrogen estimation is impacted by environmental factors and crop leaf characteristics

    PubMed Central

    Xiong, Dongliang; Chen, Jia; Yu, Tingting; Gao, Wanlin; Ling, Xiaoxia; Li, Yong; Peng, Shaobing; Huang, Jianliang

    2015-01-01

    Chlorophyll meters are widely used to guide nitrogen (N) management by monitoring leaf N status in agricultural systems, but the effects of environmental factors and leaf characteristics on leaf N estimations are still unclear. In the present study, we estimated the relationships among SPAD readings, chlorophyll content and leaf N content per leaf area for seven species grown in multiple environments. There were similar relationships between SPAD readings and chlorophyll content per leaf area for the species groups, but the relationship between chlorophyll content and leaf N content per leaf area, and the relationship between SPAD readings and leaf N content per leaf area varied widely among the species groups. A significant impact of light-dependent chloroplast movement on SPAD readings was observed under low leaf N supplementation in both rice and soybean but not under high N supplementation. Furthermore, the allocation of leaf N to chlorophyll was strongly influenced by short-term changes in growth light. We demonstrate that the relationship between SPAD readings and leaf N content per leaf area is profoundly affected by environmental factors and leaf features of crop species, which should be accounted for when using a chlorophyll meter to guide N management in agricultural systems. PMID:26303807

  19. [Characteristics and the impact factors of acid rain in Fuzhou and Xiamen 1992-2012].

    PubMed

    Zheng, Qiu-Ping; Wang, Hong; Chen, Bin-Bin; Sui, Ping; Lin, Wen

    2014-10-01

    Based on the observed acid rain data, synoptic situations and mass concentrations of atmospheric pollutants data from 1992 to 2012, the temporal variation characteristics and the impact factors of acid rain were analyzed in Fuzhou and Xiamen. The results showed that acid rain and non-acid rain accounted for 38.1% and 61.9% respectively in Fuzhou, 40.6% and 59.4% respectively in Xiamen. The annual average pH was 4.1-5.5 in Fuzhou. Acid rain pollution alleviated after 2007 in Fuzhou, and alleviated after 2006 in Xiamen. Acid rain was more serious in winter and spring than in summer and autumn. Precipitation intensity could affect the acidity of rain. Acid rain was observed more serious in southeast, southwest, west and northwest wind in Fuzhou, and more serious in northeast, southwest, west and northwest wind in Xiamen. Acid rain was most severe under the condition of transformed surface cold high, while most light under the conditions of typhoon (intertropical convergence zone) and outside of typhoon (intertropical convergence zone). There was a negative correlation between the mass concentrations of atmospheric pollutants, such as SO2, NO2, PM10, and the pH of rain in Fuzhou.

  20. Impact of resolution and noise characteristics of digital radiographic detectors on the detectability of lung nodules.

    PubMed

    Saunders, Robert S; Samei, Ehsan; Hoeschen, Christoph

    2004-06-01

    One of the unanswered questions in digital radiography is the connection between physical image quality metrics and clinical detection performance. In this paper, we examine the impact of two physical metrics, resolution and noise, on the detectability of nodules in a pulmonary background for specific digital radiographic detectors. A detection experiment was performed on a simulated image set using anatomical backgrounds from a high-quality lung radiograph and three different simulated nodule sizes (2-3.5 mm). The resolution and noise of the resulting images were modified using existing routines to simulate a selenium-based and a cesium iodide-based flat-panel detector at comparable exposures. A location-known-exactly (LKE) observer performance experiment was performed in which four experienced chest radiologists and three physicists specializing in chest radiology scored the images. The data from the observer experiment were analyzed by receiver operating characteristic (ROC) methodology. The detectability, as measured by the parameter Az, was higher for the selenium detector than the cesium iodide detector for all nodule sizes by an average of 8.5%. For one nodule size (2.75 mm), the difference between detectors was statistically significant (p < 0.01). The findings indicate that for the particular task studied, the superior resolution performance of the selenium-based detector provided better detectability of subtle lung nodules even though the images had greater noise than images obtained with the cesium iodide detector.