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. 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…

  4. 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…

  5. 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…

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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…

  15. 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…

  16. 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.

  17. Side Impact Injury Test Apparatus

    DTIC Science & Technology

    1999-02-16

    component. It is often desirable to study and evaluate the effects of automobile, airplane and other crashes that cause damage and injury due to impact ...present invention to provide an apparatus that will carry out impact tests yet minimize or eliminate destruction or damage to the test equipment and...conducting collision tests, especially of side impacts , that does not destroy or damage the test apparatus or equipment yet produces reliable and repeatable

  18. 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.

  19. 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.

  20. 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.

  1. Nickel: Impact on horticultural characteristics

    USDA-ARS?s Scientific Manuscript database

    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...

  2. Glatz Prototype Seat Impact Testing

    DTIC Science & Technology

    2013-07-03

    from design drawings. A Pure Horizontal test was also conducted to determine structural strength of the Glatz prototype seat. Biodynamic response...Aerospace Biodynamics and Performance Research Team of the Applied Neuroscience Branch of the Human Effectiveness Directorate (711HPW/RHCP), under Workunit...test methodology. This testing focuses solely on the survivability of the seat and occupant biodynamics during primary aircraft impact. Secondary

  3. 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.

  4. 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.

  5. Dynamic impact testing with servohydraulic testing machines

    NASA Astrophysics Data System (ADS)

    Bardenheier, R.; Rogers, G.

    2006-08-01

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

  6. 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.

  7. Impact testing with a centrifuge

    NASA Astrophysics Data System (ADS)

    Foglietta, Jim; Olin, Malcolm; Venturi, Richard

    A test program intended to verify an aircraft wing armor protection system is described, focusing on testing methodologies, the centrifuge release system design, and aiming and system controls. Two armor impact tests were conducted which used a centrifuge to propel a large irregular projectile into a target surface. The first test was performed on the armor protected side of the simulated fuel tank. The impactor was deflected off the armored surface, damaging the armor slightly and causing a small leak in the tank. The impactor broke into three pieces. The second test was performed on the reverse side of the simulated fuel tank. The impactor penetrated the tank and remained lodged inside, causing a massive leak.

  8. 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

  9. 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.

  10. Test characteristics and potential impact of the urine LAM lateral flow assay in HIV-infected outpatients under investigation for TB and able to self-expectorate sputum for diagnostic testing.

    PubMed

    Peter, Jonny; Theron, Grant; Chanda, Duncan; Clowes, Petra; Rachow, Andrea; Lesosky, Maia; Hoelscher, Michael; Mwaba, Peter; Pym, Alex; Dheda, Keertan

    2015-07-09

    The commercially available urine LAM strip test, a point-of-care tuberculosis (TB) assay, requires evaluation in a primary care setting where it is most needed. There is currently inadequate data to guide implementation in TB and HIV-endemic settings. Adult HIV-infected outpatients with suspected pulmonary TB able to self-expectorate sputum from four primary clinics in South Africa, Zambia and Tanzania underwent diagnostic evaluation [sputum smear microscopy, Xpert-MTB/RIF, and culture (reference standard)] as part of a prospective parent study. Urine LAM testing (grade-2 cut-point) was performed on archived samples. Performance characteristics of LAM alone or in combination with sputum-based diagnostics were evaluated. Potential impact on 2 and 6-month morbidity (TBscore), patient dropout rates, and prognosis (death/ loss to follow-up) were evaluated. Among 583 participants with suspected TB that were HIV-infected or refused testing, the overall LAM sensitivity (95 % CI; n/N) and in the CD4 ≤ 100 cells/mm(3) sub-group was 22.7 % (16.6-28.7; 41/181) and 30.4 % (17.1-43.7; 14/46), respectively. Overall specificity was 93.0 % (90.5-95.6; 361/388). Amongst culture-positive TB cases, adjunctive LAM testing did not improve the sensitivity of either sputum Xpert-MTB/RIF [78.2 % (69.8-86.7; 72/92) versus 76.1 % (67.4-84.8; 70/92), p = 0.7] or smear-microscopy [56.2 % (45.9-66.5; 50/89) versus 43.8 % (33.5-54.1; 39/89), p = 0.1). Clinic-based LAM, as an adjunct to either smear microscopy or Xpert MTB/RIF same-day testing, would neither have decreased patient dropout, nor increased same-day treatment initiation in this clinical setting where same-day chest radiography was available. LAM positivity was associated with 6-month lost-to-follow-up/death (AOR 4.4; p = 0.002) but not TBscore (at baseline or change in TBscore 2-months post-treatment) (p = 0.17). In African HIV-TB co-infected outpatients able to self-expectorate sputum LAM had limited sensitivity even at low CD4

  11. Mallet impact test. Final report

    SciTech Connect

    West, G.T.

    1982-09-01

    Small and large scale apparatus were constructed to mechanically-simulate forces and durations measured on instrumented mallets during lathe centering operations using mock explosive billets. Tests were conducted on LX-10 samples. In addition to normal mallet impacts, simulation of glancing blows was attempted. There were no detectable reactions of the LX-10, although the simulated glancing blows were conducted at force levels high enough to melt the plastic hammer tip. These levels are considered much higher than those within a human's capability. It is concluded that the probability of LX-10 initiation as a result of an operator mallet blow is very unlikely.

  12. 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.

  13. 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

  14. Pendulum impact tests of wooden and steel highway guardrail posts

    Treesearch

    Charles J. Gatchell; Jarvis D. Michie

    1974-01-01

    Impact strength characteristics of southern pine, red oak, and steel highway guardrail posts were evaluated in destructive impact testing with a 4,000-pound pendulum at the Southwest Research Institute. Effects were recorded with high-speed motion-picture equipment. Comparisons were based on reactions to the point of major post failure. Major comparisons of 6x6-inch...

  15. 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).

  16. The effect of ceramic/metal gradient armor's components characteristic on its impact-resistant characteristic

    SciTech Connect

    Liu Lisheng; Zhang Qingjie; Zhai Pengcheng; Cao Dongfeng

    2008-02-15

    The effect of ceramic/metal gradient armor's components characteristic on its impact-resistant characteristic has been investigated by a new modified Alekseevskii-Tate equation. The following researching work is done by the former model [1]: the effect of ceramic layer on the impact-resistant characteristic, the effect of gradient layer on the impact-resistant characteristic and the effect of metal layer on the impact-resistant characteristic.

  17. 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…

  18. The NASA JSC Hypervelocity Impact Test Facility (HIT-F)

    NASA Technical Reports Server (NTRS)

    Crews, Jeanne L.; Christiansen, Eric L.

    1992-01-01

    The NASA Johnson Space Center Hypervelocity Impact Test Facility was created in 1980 to study the hypervelocity impact characteristics of composite materials. The facility consists of the Hypervelocity Impact Laboratory (HIRL) and the Hypervelocity Analysis Laboratory (HAL). The HIRL supports three different-size light-gas gun ranges which provide the capability of launching particle sizes from 100 micron spheres to 12.7 mm cylinders. The HAL performs three functions: (1) the analysis of data collected from shots in the HIRL, (2) numerical and analytical modeling to predict impact response beyond test conditions, and (3) risk and damage assessments for spacecraft exposed to the meteoroid and orbital debris environments.

  19. 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.

  20. 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.

  1. 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;…

  2. 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...

  3. 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...

  4. 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...

  5. Reaction Characteristic for Various Scale Explosive under Mild Impact

    NASA Astrophysics Data System (ADS)

    Wen, Yushi; Dai, Xiaogan; Han, Yong; Xiang, Yong

    2014-05-01

    This work presents a varying trend of impact ignition threshold denoted by minimum impact velocity to trigger an ignition when the scale of the explosive changes. The effects of explosive scale factors on impact-induced reaction degree were investigated using Steven tests and numerical simulation for polymer-bonded explosive-C03 (a cyclotetramethylene tetranitramine [HMX]-based explosive) impacted by projectiles of various velocities. Two scale factors-that is, axial thickness and radius-were studied through various scale samples including Φ98 mm × 13 mm, Φ98 mm × 39 mm, Φ140 mm × 13 mm, and Φ140 mm × 39 mm. The velocities of projectiles and the impact and ignition processes were analyzed using a high-speed camera. The pressure histories were measured by embedded manganin pressure gauges and poly vinylidene fluoride stress gauges. The reaction overpressures of the explosive were obtained by blast pressure gauges to evaluate the reaction degree. The effects of explosive scale factor on reaction degree and characteristics under mild impact were summarized. In a certain range (larger than the diameter of the impact projectile), different sample diameters do not influence the velocity threshold, but the thickness of the samples does; that is, the velocity threshold increases with the thickness of the sample. The study also indicates that the ignition and explosion in Steven tests are mainly triggered by the overlapping of direct impact and reflected stress waves. Our numerical simulations results of pressure and ignition times are consistent with the experimental data. The obtained knowledge can be used to evaluate the safety of different scale HMX-based explosives under accidental impact or falls.

  6. 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.

  7. 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.

  8. Light-weight radioisotope heater impact tests

    SciTech Connect

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

    1998-12-31

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

  9. Measurement Techniques for Hypervelocity Impact Test Fragments

    NASA Technical Reports Server (NTRS)

    Hill, Nicole E.

    2008-01-01

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

  10. 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...

  11. 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.

  12. 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.

  13. 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.

  14. Structural Behavior Under Precision Impact Tests

    DTIC Science & Technology

    1996-08-01

    ASPECTS OF IMPACT TESTING The problem of impact between two bodies has been studied extensively (for example, Eibl 1987, Feyerabend 1988, Krauthammer...Concrete for Hazard Protection, Edinburgh, Scotland, pp. 175-186. Feyerabend , M., 1988, "Der harte Querstoss auf Stützen aus Stahl und Stahlbeton

  15. Impact testing of textile composite materials

    NASA Technical Reports Server (NTRS)

    Portanova, Marc

    1995-01-01

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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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…

  4. 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…

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. Student Interaction Characteristics during Collaborative Group Testing

    ERIC Educational Resources Information Center

    Giuliodori, Mauricio J.; Lujan, Heidi L.; DiCarlo, Stephen E.

    2009-01-01

    We used collaborative testing in a veterinary physiology course (65 students) to answer the following questions: 1) do students with individual correct responses or students with individual incorrect responses change their answers during group testing? and 2) do high-performing students make the decisions, that is, are low-performing students…

  11. 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.

  12. 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.

  13. Impact of swelling characteristics on the permselective ...

    EPA Pesticide Factsheets

    The removal of water from organic solvents and biofuels, including lower alcohols (i.e., methanol, ethanol, propanol, and butanol), is necessary for the production, blending, and reuse of those organic compounds. Water forms an azeotrope with many hydrophilic solvents, complicating the separation of water/solvent mixtures. The use of water-selective membranes in a pervaporation or vapor permeation process enables the removal of water from the solvents, even when an azeotrope is present. Common hydrophilic polymer membranes often swell in water, resulting in permeabilities and selectivities that are dependent on the water content of the feed mixture. Recent work has shown the benefit of overcoating a hydrophilic water-permselective membrane with a non-swelling perfluoropolymer film [1,2]. The perfluoropolymer layer reduces the activity of water the hydrophilic polymer layer experiences, thereby reducing swelling in that layer and increasing the water selectivity of the multi-layer membrane relative to the selectivity of the base hydrophilic polymer, usually at the expense of permeability. In this work, the effect of overcoating the hydrophilic layer with polymer films of various swelling characteristics was modelled. Top layers that swell in the solvent offer some advantages, particularly with regard to the water permeance of the multi-layer composite. 1. Huang, Y.; Baker, R. W.; Wijmans, J. G. Perfluoro-coated hydrophilic membranes with improved selectivity. In

  14. 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.

  15. 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.

  16. Impact Landing Dynamics Facility Crash Test

    NASA Image and Video Library

    1975-08-03

    Photographed on: 08/03/75. -- By 1972 the Lunar Landing Research Facility was no longer in use for its original purpose. The 400-foot high structure was swiftly modified to allow engineers to study the dynamics of aircraft crashes. "The Impact Dynamics Research Facility is used to conduct crash testing of full-scale aircraft under controlled conditions. The aircraft are swung by cables from an A-frame structure that is approximately 400 ft. long and 230 foot high. The impact runway can be modified to simulate other grand crash environments, such as packed dirt, to meet a specific test requirement." "In 1972, NASA and the FAA embarked on a cooperative effort to develop technology for improved crashworthiness and passenger survivability in general aviation aircraft with little or no increase in weight and acceptable cost. Since then, NASA has "crashed" dozens of GA aircraft by using the lunar excursion module (LEM) facility originally built for the Apollo program." This photograph shows Crash Test No. 7. Crash Test: Test #7

  17. 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.

  18. 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…

  19. 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.

  20. 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

  1. A Test Characteristic Curve Linking Method for the Testlet Model

    ERIC Educational Resources Information Center

    Li, Yanmei; Bolt, Daniel M.; Fu, Jianbin

    2005-01-01

    When tests are made up of testlets, a testlet-based item response theory (IRT) model may be used to account for local dependence among items from a common testlet. This study presents a new test characteristic curve method to link calibrations based on the Bradlow, Wainer, and Wang (1999) testlet model. Procedures for calculating the test…

  2. 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…

  3. 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…

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 49 CFR 325.53 - Site characteristics; stationary test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 5 2013-10-01 2013-10-01 false Site characteristics; stationary test. 325.53 Section 325.53 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION GENERAL REGULATIONS COMPLIANCE WITH INTERSTATE MOTOR CARRIER NOISE EMISSION STANDARDS...

  12. Accelerated life testing effects on CMOS microcircuit characteristics

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Modifications and additions to the present process of making CMOS microcircuits which are designed to provide protective layers on the chip to guard against moisture and contaminants were investigated. High and low temperature Si3N4 protective layers were tested on the CMOS microcircuits and no conclusive improvements in device reliability characteristics were evidenced.

  13. 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…

  14. The influence of cervical muscle characteristics on head impact biomechanics in football.

    PubMed

    Schmidt, Julianne D; Guskiewicz, Kevin M; Blackburn, J Troy; Mihalik, Jason P; Siegmund, Gunter P; Marshall, Stephen W

    2014-09-01

    An athlete is thought to reduce head acceleration after impact by contracting the cervical musculature, which increases the effective mass of the head. To compare the odds of sustaining higher magnitude in-season head impacts between athletes with higher and lower preseason performance on cervical muscle characteristics. Cohort study; Level of evidence, 2. Forty-nine high school and collegiate American football players completed a preseason cervical testing protocol that included measures of cervical isometric strength, muscle size, and response to cervical perturbation. Head impact biomechanics were captured for each player using the Head Impact Telemetry System. A median split was used to categorize players as either high or low performers for each of the following outcome measures: isometric strength (peak torque, rate of torque development), muscle size (cross-sectional area), and response to cervical perturbation (stiffness, angular displacement, muscle onset latency). The odds of sustaining moderate and severe head impacts were computed against the reference odds of sustaining mild head impacts across cervical characteristic categorizations. Linemen with stronger lateral flexors and composite cervical strength had about 1.75 times' increased odds of sustaining moderate linear head impacts rather than mild impacts compared with weaker linemen. Players who developed extensor torque more quickly had 2 times the increased odds of sustaining severe linear head impacts (odds ratio [OR], 2.10; 95% CI, 1.08-4.05) rather than mild head impacts. However, players with greater cervical stiffness had reduced odds of sustaining both moderate (OR, 0.77; 95% CI, 0.61-0.96) and severe (OR, 0.64; 95% CI, 0.46-0.89) head impacts compared with players with less cervical stiffness. The study findings showed that greater cervical stiffness and less angular displacement after perturbation reduced the odds of sustaining higher magnitude head impacts; however, the findings did not

  15. Engine exhaust characteristics evaluation in support of aircraft acoustic testing

    NASA Astrophysics Data System (ADS)

    Ennix, Kimberly A.

    1994-02-01

    NASA Dryden Flight Research Facility and NASA Langley Research Center completed a joint acoustic flight test program. Test objectives were (1) to quantify and evaluate subsonic climb-to-cruise noise and (2) to obtain a quality noise database for use in validating the Aircraft Noise Prediction Program. These tests were conducted using aircraft with engines that represent the high nozzle pressure ratio of future transport designs. Test flights were completed at subsonic speeds that exceeded Mach 0.3 using F-18 and F-16XL aircraft. This paper describes the efforts of NASA Dryden Flight Research Facility in this flight test program. Topics discussed include the test aircraft, setup, and matrix. In addition, the engine modeling codes and nozzle exhaust characteristics are described.

  16. Engine exhaust characteristics evaluation in support of aircraft acoustic testing

    NASA Technical Reports Server (NTRS)

    Ennix, Kimberly A.

    1994-01-01

    NASA Dryden Flight Research Facility and NASA Langley Research Center completed a joint acoustic flight test program. Test objectives were (1) to quantify and evaluate subsonic climb-to-cruise noise and (2) to obtain a quality noise database for use in validating the Aircraft Noise Prediction Program. These tests were conducted using aircraft with engines that represent the high nozzle pressure ratio of future transport designs. Test flights were completed at subsonic speeds that exceeded Mach 0.3 using F-18 and F-16XL aircraft. This paper describes the efforts of NASA Dryden Flight Research Facility in this flight test program. Topics discussed include the test aircraft, setup, and matrix. In addition, the engine modeling codes and nozzle exhaust characteristics are described.

  17. Engine exhaust characteristics evaluation in support of aircraft acoustic testing

    NASA Technical Reports Server (NTRS)

    Ennix, Kimberly A.

    1993-01-01

    NASA Dryden Flight Research Facility and NASA Langley Research Center completed a joint acoustic flight test program. Test objectives were (1) to quantify and evaluate subsonic climb-to-cruise noise and (2) to obtain a quality noise database for use in validating the Aircraft Noise Prediction Program. These tests were conducted using aircraft with engines that represent the high nozzle pressure ratio of future transport designs. Test flights were completed at subsonic speeds that exceeded Mach 0.3 using F-18 and F-16XL aircraft. This paper describes the efforts of NASA Dryden Flight Research Facility in this flight test program. Topics discussed include the test aircraft, setup, and matrix. In addition, the engine modeling codes and nozzle exhaust characteristics are described.

  18. 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.

  19. 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.

  20. 16 CFR § 1203.17 - Impact attenuation test.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... by measuring the acceleration of the test headform during impact. Acceleration is measured with a... within 5 degrees of vertical when the test headform is in the impact position. The acceleration data... dropped onto the MEP at an impact velocity of 5.44 m/s±2%. (Typically, this requires a minimum drop height...

  1. Normal dynamic deformation characteristics of non-consecutive jointed rock masses under impact loads

    NASA Astrophysics Data System (ADS)

    Zeng, Sheng; Jiang, Bowei; Sun, Bing

    2017-08-01

    In order to study deformation characteristics of non-consecutive single jointed rock masses under impact loads, we used the cement mortar materials to make simulative jointed rock mass samples, and tested the samples under impact loads by the drop hammer. Through analyzing the time-history signal of the force and the displacement, first we find that the dynamic compression displacement of the jointed rock mass is significantly larger than that of the intact jointless rock mass, the compression displacement is positively correlated with the joint length and the impact height. Secondly, the vertical compressive displacement of the jointed rock mass is mainly due to the closure of opening joints under small impact loads. Finally, the peak intensity of the intact rock mass is larger than that of the non-consecutive jointed rock mass and negatively correlated with the joint length under the same impact energy.

  2. 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.

  3. 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.

  4. Scientists popularizing science: characteristics and impact of TED talk presenters.

    PubMed

    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.

  5. 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

  6. 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.

  7. Halstead-Reitan characteristics of nonimpact and impact mTBI litigants and insurance claimants.

    PubMed

    Sweeney, James Ernest; Johnson, Andrew M

    2017-08-29

    The purpose of this study was to investigate possible neuropsychological differences in Halstead-Reitan characteristics between motor vehicle accident litigants and insurance claimants that sustained uncomplicated mild traumatic brain injury (mTBI) and did or did not sustain direct impact to the head (i.e., Impact vs. Nonimpact mTBI), and to compare these clinical groups with a control group that did not suffer mTBI (No mTBI). The Tactile Form Recognition Test (TFR) was the only level of performance test in the Halstead-Reitan Battery (HRB) that generated statistically significant differences. The TFR resembles a complex reaction time test. TFR response time was significantly longer for Nonimpact mTBI patients than for Impact mTBI and No mTBI participants. Frequency comparisons of abnormal score patterns demonstrated that Nonimpact patients produced significantly more aberrant Impairment Index vs. FSIQ score patterns than Impact and No mTBI participants. Given the components of the score pattern, this finding suggests that Nonimpact patients may experience less recovery from neuropsychological deficits than Impact participants. Complex perceptual reaction times and score patterns comparing sensitive and "hold" test results may represent heuristic avenues of future research in the study of compensation-seeking Nonimpact and Impact mTBI patients.

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

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.11 Marking the impact test line. Prior to testing, the impact test line shall be determined for each helmet in the following manner. (a) Position the helmet on the appropriate headform as specified by the manufacturer's helmet positioning index...

  9. 16 CFR 1203.11 - Marking the impact test line.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.11 Marking the impact test line. Prior to testing, the impact test line shall be determined for each helmet in the following manner. (a) Position the helmet on the appropriate headform as specified by the manufacturer's helmet positioning index...

  10. 16 CFR 1203.11 - Marking the impact test line.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.11 Marking the impact test line. Prior to testing, the impact test line shall be determined for each helmet in the following manner. (a) Position the helmet on the appropriate headform as specified by the manufacturer's helmet positioning index...

  11. 16 CFR 1203.11 - Marking the impact test line.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... REGULATIONS SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.11 Marking the impact test line. Prior to testing, the impact test line shall be determined for each helmet in the following manner. (a) Position the helmet on the appropriate headform as specified by the manufacturer's helmet positioning index...

  12. 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.

  13. SMALL-SCALE IMPACT SENSITIVITY TESTING ON EDC37

    SciTech Connect

    HSU, P C; HUST, G; MAIENSCHEIN, J L

    2008-04-28

    EDC37 was tested at LLNL to determine its impact sensitivity in the LLNL's drop hammer system. The results showed that impact sensitivities of the samples were between 86 cm and 156 cm, depending on test methods. EDC37 is a plastic bonded explosive consisting of 90% HMX, 1% nitrocellulose and binder. We recently conducted impact sensitivity testing in our drop hammer system and the results are presented in this report.

  14. 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

  15. 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.

  16. 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…

  17. 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…

  18. [Characteristics of nursing publications in journals with impact factor].

    PubMed

    Díaz-Membrives, Montserrat; Farrero-Muñoz, Sara; Lluch-Canut, Maria Teresa

    2012-01-01

    The aims of this study were to identify publishing characteristics of nursing journals with impact factor (IF) and to discuss methodological characteristics and authorship of original papers with IF. A retrospective descriptive study. A literature review was performed between 2009 and 2010 including all nursing publications indexed in the Journal Citation Reports (JCR) and analysis of selected original papers. The information was analyzed using descriptive statistics. In 2009, there were 74 nursing journals with an IF and in 2010 increased upto 91. In 2010, 93.5% were published in English, bimonthly journals predominated (43%) and for specialties, maternity and paediatrics were the most frequent (25%). Almost three-quarters (72.8%) of the original articles were quantitative studies performed mostly in hospitals (42%) and with patient samples (34.6%). The most frequently studied topics were "evidence-based care" (23.5%), "measuring quality care" (18.52%) and "effectiveness of nursing interventions" (14.81%). Authors came mostly from Europe and United States and the most common workplace was a university. Nursing Journals' Impact Factor has increased, particularly in areas of nurse specialization. Nursing publications in the Spanish language with IF are still incipient. Quantitative research continues to dominate. The main topics are effectiveness, evidence, and quality care, and researchers come mostly from academic areas. Copyright © 2011 Elsevier España, S.L. All rights reserved.

  19. Personal genome testing: test characteristics to clarify the discourse on ethical, legal and societal issues.

    PubMed

    Bunnik, Eline M; Schermer, Maartje H N; Janssens, A Cecile J W

    2011-06-14

    As genetics technology proceeds, practices of genetic testing have become more heterogeneous: many different types of tests are finding their way to the public in different settings and for a variety of purposes. This diversification is relevant to the discourse on ethical, legal and societal issues (ELSI) surrounding genetic testing, which must evolve to encompass these differences. One important development is the rise of personal genome testing on the basis of genetic profiling: the testing of multiple genetic variants simultaneously for the prediction of common multifactorial diseases. Currently, an increasing number of companies are offering personal genome tests directly to consumers and are spurring ELSI-discussions, which stand in need of clarification. This paper presents a systematic approach to the ELSI-evaluation of personal genome testing for multifactorial diseases along the lines of its test characteristics. This paper addresses four test characteristics of personal genome testing: its being a non-targeted type of testing, its high analytical validity, low clinical validity and problematic clinical utility. These characteristics raise their own specific ELSI, for example: non-targeted genetic profiling poses serious problems for information provision and informed consent. Questions about the quantity and quality of the necessary information, as well as about moral responsibilities with regard to the provision of information are therefore becoming central themes within ELSI-discussions of personal genome testing. Further, the current low level of clinical validity of genetic profiles raises questions concerning societal risks and regulatory requirements, whereas simultaneously it causes traditional ELSI-issues of clinical genetics, such as psychological and health risks, discrimination, and stigmatization, to lose part of their relevance. Also, classic notions of clinical utility are challenged by the newer notion of 'personal utility.' Consideration

  20. Personal genome testing: Test characteristics to clarify the discourse on ethical, legal and societal issues

    PubMed Central

    2011-01-01

    Background As genetics technology proceeds, practices of genetic testing have become more heterogeneous: many different types of tests are finding their way to the public in different settings and for a variety of purposes. This diversification is relevant to the discourse on ethical, legal and societal issues (ELSI) surrounding genetic testing, which must evolve to encompass these differences. One important development is the rise of personal genome testing on the basis of genetic profiling: the testing of multiple genetic variants simultaneously for the prediction of common multifactorial diseases. Currently, an increasing number of companies are offering personal genome tests directly to consumers and are spurring ELSI-discussions, which stand in need of clarification. This paper presents a systematic approach to the ELSI-evaluation of personal genome testing for multifactorial diseases along the lines of its test characteristics. Discussion This paper addresses four test characteristics of personal genome testing: its being a non-targeted type of testing, its high analytical validity, low clinical validity and problematic clinical utility. These characteristics raise their own specific ELSI, for example: non-targeted genetic profiling poses serious problems for information provision and informed consent. Questions about the quantity and quality of the necessary information, as well as about moral responsibilities with regard to the provision of information are therefore becoming central themes within ELSI-discussions of personal genome testing. Further, the current low level of clinical validity of genetic profiles raises questions concerning societal risks and regulatory requirements, whereas simultaneously it causes traditional ELSI-issues of clinical genetics, such as psychological and health risks, discrimination, and stigmatization, to lose part of their relevance. Also, classic notions of clinical utility are challenged by the newer notion of 'personal

  1. Orion MPCV Water Landing Test at Hydro Impact Basin

    NASA Image and Video Library

    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...

  2. 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…

  3. 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.

  4. 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.

  5. Impact of child and family characteristics on cerebral palsy treatment.

    PubMed

    Rackauskaite, Gija; Uldall, Peter W; Bech, Bodil H; Østergaard, John R

    2015-10-01

    The aim of the study was to describe the relationship between the child's and family's characteristics and the most common treatment modalities in a national population-based sample of 8- to 15-year-old children with cerebral palsy. A cross-sectional study, based on the Danish Cerebral Palsy Registry. The parents of 462 children answered a questionnaire about their child's treatment and the family's characteristics (living with a single parent, having siblings, living in a city, parental education level). Descriptive and logistic regression analyses were performed for every treatment modality, stratified by Gross Motor Function Classification System (GMFCS) level. An IQ below 85 was associated with weekly therapy in GMFCS level I (adjusted odds ratio [ORadj ] 2.5 [CI 1.1-5.7]) and the use of oral spasmolytics in GMFCS levels III to V (ORadj 3.1 [CI 1.3-7.4]). Older children in GMFCS levels III to V used daily orthoses less frequently (ORadj 0.7 [CI 0.6-0.9] per year). Of all of the family characteristics studied, only the parents' education level had significant associations with more than one treatment modality. A child's cognitive function showed an impact on treatment of the motor impairment in children 8 to 15 years of age with cerebral palsy. Parental education level may influence the choice of treatment. © 2015 Mac Keith Press.

  6. [Characteristics of allergic conjunctivitis with positive skin prick test].

    PubMed

    Yang, S; Jiang, Y; Jin, Y M; Zhang, J Y; Li, Y

    2017-09-11

    Objective: To observe the clinical characteristics of allergic conjunctivitis, and the correlations with skin prick test results. Methods: A retrospective study. Forty patients with positive skin prick test result were included. Patients underwent an ophthalmologic examination to identify their primary presenting signs and symptoms. The allergy types were divided into 5 groups. All dates were analyzed for the dependence, normality and homogeneity of variance. Chi-square test, Mann-Whitney U test, Kruskal-Wallis H test and Spearman correlation analysis were performed accordingly. Results: Among 40 patients, 18(45.0%) had a clinical diagnosis of seasonal allergic conjunctivitis, 14(35.0%) had perennial allergic conjunctivitis, 5(12.5%) had vernal keratoconjunctivitis, and 2(5.0%) had atopic keratoconjunctivits, and 1(2.5%) had giant papillary conjunctivitis. There was no significant difference in the number of symptoms and signs score among different types of allergic conjunctivitis, the score of itching and hyperemia had a positive relationship with the number of positive allergens (r=0.74, P<0.05. r=0.96, P<0.05). The primary symptoms and signs are itching and hyperemia; dust and pollens are the most common allergens. The more positive result of the test of the allergen, the more symptoms and signs encountered in terms of severity. Conclusion: Seasonal allergic conjunctivitis was the most prevalent disorder, the most important clinical characteristics of allergic conjunctivitis are itching and conjunctival congestion, the main allergens are dust and pollens, patients may be sensitive to multiple allergens. (Chin J Ophthalmol, 2017, 53: 689-693).

  7. 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.

  8. 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.

  9. 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.

  10. Membrane characteristics for biological blast overpressure testing using blast simulators.

    PubMed

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

    2014-01-01

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

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  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 1203.17 - Impact attenuation test.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... the acceleration of the test headform during impact. Acceleration is measured with a uniaxial... degrees of vertical when the test headform is in the impact position. The acceleration data channel and... velocity of 5.44 m/s±2%. (Typically, this requires a minimum drop height of 1.50 meters (4.9 ft) plus a...

  18. 16 CFR 1203.17 - Impact attenuation test.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the acceleration of the test headform during impact. Acceleration is measured with a uniaxial... degrees of vertical when the test headform is in the impact position. The acceleration data channel and... velocity of 5.44 m/s±2%. (Typically, this requires a minimum drop height of 1.50 meters (4.9 ft) plus a...

  19. 16 CFR 1203.17 - Impact attenuation test.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... the acceleration of the test headform during impact. Acceleration is measured with a uniaxial... degrees of vertical when the test headform is in the impact position. The acceleration data channel and... velocity of 5.44 m/s±2%. (Typically, this requires a minimum drop height of 1.50 meters (4.9 ft) plus a...

  20. 16 CFR 1203.17 - Impact attenuation test.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the acceleration of the test headform during impact. Acceleration is measured with a uniaxial... degrees of vertical when the test headform is in the impact position. The acceleration data channel and... velocity of 5.44 m/s±2%. (Typically, this requires a minimum drop height of 1.50 meters (4.9 ft) plus a...

  1. Hypersonic aerodynamic characteristics for Langley Test Technique Demonstrator

    NASA Technical Reports Server (NTRS)

    Phillips, W. P.; Cruz, C. I.

    1993-01-01

    Experimental longitudinal and lateral-directional aerodynamic characteristics were obtained for a generic transatmospheric vehicle concept referred to as the Langley Test Technique Demonstrator. The baseline configuration, without engine modules, was longitudinally and directionally unstable over the hypersonic Mach number range of the investigation and exhibited untrimmed (L/D)max levels between 2.6 and 2.8. Adding various engine modules to the baseline configuration produced mainly, degradations in lift-to-drag ratio. In general, longitudinal aerodynamic coefficients predicted with an engineering code referred to as Aerodynamic Preliminary Analysis System (APAS) were in qualitative, and often quantitative agreement with measurement.

  2. 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…

  3. 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.

  4. 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…

  5. 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.

  6. Aerodynamic characteristics of the planetary atmosphere experiments test entry probe

    NASA Technical Reports Server (NTRS)

    Sammonds, R. I.; Kruse, R. L.

    1975-01-01

    The aerodynamic characteristics of the Planetary Atmosphere Experiments Test entry probe were determined experimentally in ballistic range tests over a wide range of Mach and Reynolds numbers, and were compared with full-scale flight results. The ground facility data agreed with the full-scale data within 2 to 3% in drag coefficient, and within 5 to 10% in static stability, at the higher Mach numbers. Comparisons of the flight data with conventional wind-tunnel data indicated a significant disagreement in drag coefficient in the transonic speed range suggestive of important sting or wall interference effects. Variations in drag coefficient with Mach number were very small hypersonically, but variations with Reynolds number were of the order of 15% at a free-stream Mach number of 13 over the Reynolds number range from 10,000 to 1,000,000. Variations in the lift and static-stability curves with Mach number and Reynolds number were also defined.

  7. DebriSat Hypervelocity Impact Test

    DTIC Science & Technology

    2015-08-01

    public release; distribution unlimited.  Targets: Scaled Multishock Shield, DebrisLV, and DebriSat  500-600 g hollow aluminum and nylon projectile...solar cells), NBK7 glass, titanium, sapphire, T1000 fiber, M55J carbon fiber, PVE film (sheet, wire ), kevlar, HDPE, polyurethane plastic, mylar...impact project. The design (Fig. 7) used a hollow aluminum cylinder made of 7075-T651 aluminum with a nylon sleeve. During assembly the aluminum

  8. Research on resistance characteristics of YBCO tape under short-time DC large current impact

    NASA Astrophysics Data System (ADS)

    Zhang, Zhifeng; Yang, Jiabin; Qiu, Qingquan; Zhang, Guomin; Lin, Liangzhen

    2017-06-01

    Research of the resistance characteristics of YBCO tape under short-time DC large current impact is the foundation of the developing DC superconducting fault current limiter (SFCL) for voltage source converter-based high voltage direct current system (VSC-HVDC), which is one of the valid approaches to solve the problems of renewable energy integration. SFCL can limit DC short-circuit and enhance the interrupting capabilities of DC circuit breakers. In this paper, under short-time DC large current impacts, the resistance features of naked tape of YBCO tape are studied to find the resistance - temperature change rule and the maximum impact current. The influence of insulation for the resistance - temperature characteristics of YBCO tape is studied by comparison tests with naked tape and insulating tape in 77 K. The influence of operating temperature on the tape is also studied under subcooled liquid nitrogen condition. For the current impact security of YBCO tape, the critical current degradation and top temperature are analyzed and worked as judgment standards. The testing results is helpful for in developing SFCL in VSC-HVDC.

  9. The dynamic impact characteristics of tennis balls with tennis rackets.

    PubMed

    Haake, S J; Carré, M J; Goodwill, S R

    2003-10-01

    The dynamic properties of six types of tennis balls were measured using a force platform and high-speed digital video images of ball impacts on rigidly clamped tennis rackets. It was found that the coefficient of restitution reduced with velocity for impacts on a rigid surface or with a rigidly clamped tennis racket. Pressurized balls had the highest coefficient of restitution, which decreased by 20% when punctured. Pressureless balls had a coefficient of restitution approaching that of a punctured ball at high speeds. The dynamic stiffness of the ball or the ball-racket system increased with velocity and pressurized balls had the highest stiffness, which decreased by 35% when punctured. The characteristics of pressureless balls were shown to be similar to those of punctured balls at high velocity and it was found that lowering the string tension produced a smaller range of stiffness or coefficient of restitution. It was hypothesized that players might consider high ball stiffness to imply a high coefficient of restitution. Plots of coefficient of restitution versus stiffness confirmed the relationship and it was found that, generally, pressurized balls had a higher coefficient of restitution and stiffness than pressureless balls. The players might perceive these parameters through a combination of sound, vibration and perception of ball speed off the racket.

  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. Spreading characteristics of nanofluid droplets impacting onto a solid surface.

    PubMed

    Murshed, S M Sohel; de Castro, C A Nieto

    2011-04-01

    This paper reports an experimental investigation on the spreading characteristics of nanofluid droplets impinging on aluminum substrate under the influence of several key factors such as nanoparticle volume fraction, substrate temperature, and the Weber number. Sample nanofluid used is prepared by dispersing several volumetric concentrations (1 to 5%) of titanium dioxide nanoparticles in ethylene glycol. The entire dynamic process of each droplet collision with the substrate surface and the spreading phenomena is captured by using a high speed camera and then the transient spreading diameter and height of droplet are determined. It is found that the higher the concentration of nanoparticles the larger the spreading diameter of nanofluid droplet. As the surface temperature increases, the overall spreading diameter and height of nanofluid droplet significantly decreases and increases, respectively. At larger Weber number, the final spreading of the nanofluid droplet is also found to be larger than that of lower Weber number. Present results demonstrate that spreading characteristics of nanofluid droplets impacting onto solid surface are greatly influenced by each of the aforementioned factors.

  12. [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.

  13. [Characteristics of systematic reviews about the impact of pharmacists].

    PubMed

    Tanguay, C; Guérin, A; Bussières, J-F

    2014-11-01

    The pharmacists' role is varied and numerous articles evaluate the outcomes of pharmaceutical interventions. The main objectives of this study were to establish the characteristics of systematic reviews about pharmacists' interventions that were published in the last five years. A literature search was performed on Pubmed for French and English articles published between 01-01-2008 and 31-05-2013. Systematic reviews that presented the role, the interventions and the impact of pharmacists were selected by two research assistants. A total of 46 systematic reviews was identified, amongst which one third (n=15/46, 33 %) were meta-analyses. A quarter of systematic reviews did not evaluate the quality of included articles (n=13/46, 28 %). Twelve themes were identified. A median [min-max] of 16 [2-298] articles was included per systematic review. The most frequent pharmaceutical activities were patient counseling (n=41 systematic reviews), patient chart review (n=29), pharmacotherapy evaluation (n=27) and recommendations (n=26). The least frequent activities were teaching others than patients (n=12) and medical rounds participation (n=7). Many elements can influence the completion of pharmacy practice research projects; however, there exists no link between the presence of systematic reviews and the importance of pharmacists in a given healthcare program. This study presents the characteristics of 46 systematic reviews about pharmacists interventions published since 2008. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  14. Light-weight radioisotope heater unit (LWRHU) impact tests

    SciTech Connect

    Reimus, M.A.; Rinehart, G.H.; Herrera, A.; Lopez, B.; Lynch, C.; Moniz, P.

    1998-01-01

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

  15. Light-weight radioisotope heater unit (LWRHU) impact tests

    SciTech Connect

    Reimus, M. A. H.; Rinehart, G. H.; Herrera, A.; Lopez, B.; Lynch, C.; Moniz, P.

    1998-01-15

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

  16. 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.

  17. 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.

  18. 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.

  19. Statistical characteristics of mechanical heart valve cavitation in accelerated testing.

    PubMed

    Wu, Changfu; Hwang, Ned H C; Lin, Yu-Kweng M

    2004-07-01

    Cavitation damage has been observed on mechanical heart valves (MHVs) undergoing accelerated testing. Cavitation itself can be modeled as a stochastic process, as it varies from beat to beat of the testing machine. This in-vitro study was undertaken to investigate the statistical characteristics of MHV cavitation. A 25-mm St. Jude Medical bileaflet MHV (SJM 25) was tested in an accelerated tester at various pulse rates, ranging from 300 to 1,000 bpm, with stepwise increments of 100 bpm. A miniature pressure transducer was placed near a leaflet tip on the inflow side of the valve, to monitor regional transient pressure fluctuations at instants of valve closure. The pressure trace associated with each beat was passed through a 70 kHz high-pass digital filter to extract the high-frequency oscillation (HFO) components resulting from the collapse of cavitation bubbles. Three intensity-related measures were calculated for each HFO burst: its time span; its local root-mean-square (LRMS) value; and the area enveloped by the absolute value of the HFO pressure trace and the time axis, referred to as cavitation impulse. These were treated as stochastic processes, of which the first-order probability density functions (PDFs) were estimated for each test rate. Both the LRMS value and cavitation impulse were log-normal distributed, and the time span was normal distributed. These distribution laws were consistent at different test rates. The present investigation was directed at understanding MHV cavitation as a stochastic process. The results provide a basis for establishing further the statistical relationship between cavitation intensity and time-evolving cavitation damage on MHV surfaces. These data are required to assess and compare the performance of MHVs of different designs.

  20. 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…

  1. 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…

  2. 30 CFR 7.46 - Impact test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... tabs which extend from the body of the filler caps. (3) Cracks in the cell cover, cells, or filler... with which the covers are to be approved, including any support blocks, with the battery cells... individual cells. At the test temperature range of 65 °F -80 °F (18.3 °C-26.7 °C), apply a dynamic force of...

  3. Characteristics of an anechoic chamber for fan noise testing

    NASA Technical Reports Server (NTRS)

    Wuzyniak, J. A.; Shaw, L. M.; Essary, J. D.

    1977-01-01

    Acoustical and mechanical design features of NASA Lewis Research Center's engine fan noise facility are described. Acoustic evaluation of the chamber, which is lined with an array of stepped wedges, is described. Results from the evaluation in terms of cut-off frequency and non-anechoic areas near the walls are detailed. Fan models are electrically driven to 20,600 RPM in either the inlet mode or exhaust mode to facilitate study of both fore and aft fan noise. Inlet noise characteristics of the first fan tested are discussed and compared to full-scale levels. Turbulence properties of the inlet flow and acoustic results are compared with and without a turbulence reducing screen over the fan inlet.

  4. 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.

  5. 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

  6. 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.

  7. 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

    ...; Hybrid III Test Dummy, ES-2re Side Impact Crash Test Dummy AGENCY: National Highway Traffic Safety... and in the agency's New Car Assessment Program. This NPRM responds to requests from test dummy... the crash test dummies, including the Hybrid III and ES-2re test dummies. DATES: You should submit...

  8. 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

    ...; Hybrid III Test Dummy, ES-2re Side Impact Crash Test Dummy AGENCY: National Highway Traffic Safety... qualification tests of several of the crash test dummies, including the Hybrid III and ES-2re test dummies... protection,'' and in the agency's New Car Assessment Program. The June 16, 2008 final rule incorporated by...

  9. 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.

  10. 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

  11. 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

  12. Small Scale Drop Tower Test for Practice Torpedo Impact Modelling

    DTIC Science & Technology

    2012-06-01

    stiffener materials tested in accordance with AS1391-2005, Metallic materials – Tensile testing at ambient temperature. Available on request is a...Height [m] Drop Carriage Mass [kg] Impact Velocity [ms-1] Rebound Velocity [ms-1] Rebound / Impact Velocity Ratio1 Impac t...Ratio1 Impac t Energ y [kJ] Nose Dent Shape Nose Dent Depth [m] Plate Dent Depth [m] Velocity Data Smoothing Length [samples

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. Aerosolization Characteristics of Hard Impact Testing of Depleted Uranium Penetrators

    DTIC Science & Technology

    1982-10-01

    32 7 Material Collected by Ventilation System Prefilters . 33 8 Round 2 Particle Size Data. .. ..... ..... ....... ...... 34 9...Round 3 Particle Size Data. .. ..... . .... ....... ...... 35 10 Round 4 Particle Size Data .. .. .. ....... . ...... ...... 36 11 Round 5 Particle Size ...39 14 Round 8 Particle Size Data .. .. .... ..... ....... ......40 15 Round 9 Particle Size Data. .. ..... ..... ....... ...... 41 16

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. An evaluation of the liquid oxygen mechanical impact test

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

    This study was conducted to evaluate the repeatability of the ambient LO2 mechanical impact test used by NASA to screen materials for oxygen service (NHB 8060.1B Test 12 Part 1, which is based on the ASTM method). Four materials were tested: Teflon, Vespel SP-21, Viton A, and nylon 6/6. Each test material was subjected to several series of tests that were conducted at different impact energy levels. The results show that the variability from series to series in the reaction threshold energy level is within the precision statement of the ASTM method. However, this precision is considerably broader than the reaction threshold implied by the NHB 8060.1B test criteria.

  9. 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.

  10. 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.

  11. 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…

  12. 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…

  13. ImPact Test-Retest Reliability: Reliably Unreliable?

    PubMed Central

    Resch, Jacob; Driscoll, Aoife; McCaffrey, Noel; Brown, Cathleen; Ferrara, Michael S.; Macciocchi, Stephen; Baumgartner, Ted; Walpert, Kimberly

    2013-01-01

    Context: Computerized neuropsychological testing is commonly used in the assessment and management of sport-related concussion. Even though computerized testing is widespread, psychometric evidence for test-retest reliability is somewhat limited. Additional evidence for test-retest reliability is needed to optimize clinical decision making after concussion. Objective: To document test-retest reliability for a commercially available computerized neuropsychological test battery (ImPACT) using 2 different clinically relevant time intervals. Design: Cross-sectional study. Setting: Two research laboratories. Patients or Other Participants: Group 1 (n = 46) consisted of 25 men and 21 women (age = 22.4 ± 1.89 years). Group 2 (n = 45) consisted of 17 men and 28 women (age = 20.9 ± 1.72 years). Intervention(s): Both groups completed ImPACT forms 1, 2, and 3, which were delivered sequentially either at 1-week intervals (group 1) or at baseline, day 45, and day 50 (group 2). Group 2 also completed the Green Word Memory Test (WMT) as a measure of effort. Main Outcome Measures: Intraclass correlation coefficients (ICCs) were calculated for the composite scores of ImPACT between time points. Repeated-measures analysis of variance was used to evaluate changes in ImPACT and WMT results over time. Results: The ICC values for group 1 ranged from 0.26 to 0.88 for the 4 ImPACT composite scores. The ICC values for group 2 ranged from 0.37 to 0.76. In group 1, ImPACT classified 37.0% and 46.0% of healthy participants as impaired at time points 2 and 3, respectively. In group 2, ImPACT classified 22.2% and 28.9% of healthy participants as impaired at time points 2 and 3, respectively. Conclusions: We found variable test-retest reliability for ImPACT metrics. Visual motor speed and reaction time demonstrated greater reliability than verbal and visual memory. Our current data support a multifaceted approach to concussion assessment using clinical examinations, symptom reports, cognitive

  14. [Characteristics and impact of metacognitive deficits in schizophrenia].

    PubMed

    Quiles, C; Prouteau, A; Verdoux, H

    2013-04-01

    The aim of this review of the literature is to summarise the definitions of metacognition, the measurement tools, the results of studies investigating metacognition in persons with schizophrenia and the therapeutic perspectives. This review is based upon a selection of articles identified using a PubMed search containing the terms "schizophrenia" and "metacognition". Cognitive deficits are present in 75 to 85% of persons with schizophrenia. According to the disability model of the World Health Organization, these cognitive deficits have an impact on social functioning, community integration and quality of life. However, heterogeneous results have been obtained by studies exploring the functional impact of cognitive deficits, suggesting that there is no direct relationship between these two characteristics. One possible explanation is that subjective factors, notably metacognition, may play an intermediate role moderating the link between cognitive deficits and functional impairment. Metacognition is defined as the evaluation and regulation of its own cognitive processes. The evaluation (or monitoring) monitors the accuracy and reliability of the cognitive task performance. Regulation (or control) promotes behavioural adjustment. Studies carried out in persons with schizophrenia show that most of them experience deficits in metacognitive performance. These metacognitive deficits are thought to be a key barrier to functioning in schizophrenia. Measurement tools are classified into two types: "independent" measurement of the cognitive task and "on line" measurements performed during the cognitive task. The subjective scale to investigate cognition in schizophrenia (SSTIC) and the metacognitive assessment scale (MAS) are two examples of questionnaires measuring metacognition independently of the cognitive task. Online measurements assess the metacognitive "monitoring" by asking the subject to evaluate between 0 and 100% of his/her degree of confidence in his

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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

  20. Impact of Fitness Characteristics on Tennis Performance in Elite Junior Tennis Players.

    PubMed

    Ulbricht, Alexander; Fernandez-Fernandez, Jaime; Mendez-Villanueva, Alberto; Ferrauti, Alexander

    2016-04-01

    The impact of fitness characteristics on tennis performance in adolescent players is not clearly understood. Therefore, the aim of the present study was to test whether physical characteristics are related to players' competitive level (i.e., national youth ranking). A secondary aim was to compare adolescent tennis players by performance level (i.e., regional selected players and the national team). A total of 902 male and female junior players (aged, 11-16 years) in Germany were evaluated using a physical testing battery: grip strength; countermovement jump; 10 and 20-m sprint; tennis-specific sprint; overhead, forehand, and backhand medicine ball throws (MBT); serve velocity and tennis-specific endurance test (hit and turn tennis test). Results showed that serve velocity (r = -0.43 to 0.64 for female subjects [♀]; r = -0.33 to 0.49 for male subjects [♂]) and upper-body power (e.g., MBT r = -0.26 to -0.49 ♀; r = -0.20 to -0.49 ♂) were the most correlated predictors of tennis performance (i.e., national youth ranking) in both female and male tennis players. Moreover, national selected players showed better performance levels than their regional counterparts, mainly in the most predictive physical characteristics (i.e., serve velocity: effect size [ES], 0.78-1.04 ♀; ES 0.92-1.02 ♂, MBT: ES, 0.66-0.88 ♀; ES, 0.67-1.04 ♂) and specific endurance (ES, 0.05-0.95 ♀; ES, 0.31-0.73 ♂). The present findings underline the importance of certain physical attributes, especially serve velocity and strength- and power-related variables (upper body), and suggest the need to include these parameters in the area of training, physical testing, and talent identification of young tennis players.

  1. 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

  2. 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.

  3. 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.

  4. Apparatus for Hot Impact Testing of Material Specimens

    NASA Technical Reports Server (NTRS)

    Pawlik, Ralph J.; Choi, Sung R.

    2006-01-01

    An apparatus for positioning and holding material specimens is a major subsystem of a system for impact testing of the specimens at temperatures up to 1,500 C. This apparatus and the rest of the system are designed especially for hot impact testing of advanced ceramics, composites, and coating materials. The apparatus includes a retaining fixture on a rotating stage on a vertically movable cross support driven by a linear actuator. These components are located below a furnace wherein the hot impact tests are performed (see Figure 1). In preparation for a test, a specimen is mounted on the retaining fixture, then the cross support is moved upward to raise the specimen, through an opening in the bottom of the furnace, to the test position inside the furnace. On one side of the furnace there is another, relatively small opening on a direct line to the specimen. Once the specimen has become heated to the test temperature, the test is performed by using an instrumented external pressurized-gas-driven gun to shoot a projectile through the side opening at the specimen.

  5. 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.

  6. 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.

  7. Addressable test matrix for measuring analog transfer characteristics of test elements used for integrated process control and device evaluation

    NASA Technical Reports Server (NTRS)

    Buehler, Martin G. (Inventor)

    1988-01-01

    A set of addressable test structures, each of which uses addressing schemes to access individual elements of the structure in a matrix, is used to test the quality of a wafer before integrated circuits produced thereon are diced, packaged and subjected to final testing. The electrical characteristic of each element is checked and compared to the electrical characteristic of all other like elements in the matrix. The effectiveness of the addressable test matrix is in readily analyzing the electrical characteristics of the test elements and in providing diagnostic information.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Vibration testing of impact-damaged composite laminates

    NASA Technical Reports Server (NTRS)

    Grady, Joseph E.; Meyn, Erwin H.

    1989-01-01

    A new test is described that can be used to measure changes in the vibration properties of impact damaged composite materials. Impact-induced delamination was observed to significantly affect natural frequencies of vibration and damping properties in cross-ply graphite/epoxy laminates. Natural frequencies are shown to drop by as much as half of their original value, and modal damping ratios can increase by a factor of up to eight when large amounts of damage are present. A simple finite element model of the damaged impact specimens was used to predict the effect of delamination on certain vibration properties. A comparison of the finite element calculations with the experimental measurements suggests that delamination was the dominant mechanism of flexural stiffness loss resulting from the transverse impact.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Description of ’Hot Spots’ Associated with Localized Shear Zones in Impact Tests

    DTIC Science & Technology

    1981-10-21

    NSWC CR 80-499 TO 00 DESCRIPTION OF "HOT SPOTS" ASSOCIATED WITH LOCALIZED SHEAR ZONES IN IMPACT TESTS BY C. STEPHEN COFFEY RONALD W. ARMSTRONG...different slip system geometries or other microstructural characteristics. Sugar, for instance, shows darkening directly under the original crystal site but...heating on promoting premature failure of high strength ferritic steel in torsion has been examined at different strain rates. 2 At a torsional shear

  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. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. Psychosocial and behavioral impact of genetic counseling and testing.

    PubMed

    Vadaparampil, Susan Thomas; Miree, Cheryl A; Wilson, Crystal; Jacobsen, Paul B

    Over a decade has passed since the clinical availability of BRCA1/2 mutation testing for Hereditary Breast and Ovarian Cancer (HBOC). The purpose of this article is to review key areas of psychosocial and behavioral research related to genetic counseling and testing for BRCA1/2 mutations. Special attention will be given to understudied issues within each of these key areas. Where appropriate, the article will also highlight the clinical and research experiences of the authors. The first area that will be reviewed is the impact of genetic testing on psychological well-being. This will be followed by a brief discussion of a practical assessment strategy for psychosocial distress in clinical settings. Next, published data on the uptake of risk management options based on genetic testing results as well as the psychosocial impact of these behaviors will be reviewed. Thirdly, research focused on understanding the decision making at various points in the genetic counseling and testing process will also be examined. Finally, the available research on genetic counseling and testing in minority communities will be presented. By recognizing and addressing the psychosocial and behavioral issues faced by patients undergoing BRCA1/2 genetic counseling and testing, researchers and providers have the potential to maximize opportunities for prevention, early detection, and healthy coping.

  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. 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)…

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Characteristics of Orthopedic Publications in High-Impact General Medical Journals.

    PubMed

    Nwachukwu, Benedict U; Kahlenberg, Cynthia A; Lehman, Jason D; Lyman, Stephen; Marx, Robert G

    2017-05-01

    Orthopedic studies are occasionally published in high-impact general medical journals; these studies are often given high visibility and have significant potential to impact health care policy and inform clinical decision-making. The purpose of this review was to investigate the characteristics of operative orthopedic studies published in high-impact medical journals. The number of orthopedic studies published in high-impact medical journals is relatively low; however, these studies demonstrate methodological characteristics that may bias toward nonoperative treatment. Careful analysis and interpretation of orthopedic studies published in these journals is warranted. [Orthopedics. 2017; 40(3):e405-e412.]. Copyright 2017, SLACK Incorporated.

  14. The "Test of Financial Literacy": Development and Measurement Characteristics

    ERIC Educational Resources Information Center

    Walstad, William B.; Rebeck, Ken

    2017-01-01

    The "Test of Financial Literacy" (TFL) was created to measure the financial knowledge of high school students. Its content is based on the standards and benchmarks stated in the "National Standards for Financial Literacy" (Council for Economic Education 2013). The test development process involved extensive item writing and…

  15. 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…

  16. 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…

  17. Nondestructive test determines overload destruction characteristics of current limiter fuses

    NASA Technical Reports Server (NTRS)

    Swartz, G. A.

    1968-01-01

    Nondestructive test predicts the time required for current limiters to blow /open the circuit/ when subjected to a given overload. The test method is based on an empirical relationship between the voltage rise across a current limiter for a fixed time interval and the time to blow.

  18. 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…

  19. 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…

  20. The Impact of Various Personal and Social Characteristics on Volunteering.

    ERIC Educational Resources Information Center

    Hughes, Philip; Black, Alan

    2002-01-01

    Analysis of Australian Community Survey data (n=6,242) identified three categories of volunteer involvement: assisting those who need help, serving the wider community, and being involved in volunteer groups. Volunteers in each category had different characteristics. Key influences were having resources to contribute, existence of recruitment…

  1. 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.

  2. Aeroacoustic Characteristics of Model Jet Test Facility Flow Conditioners

    NASA Technical Reports Server (NTRS)

    Kinzie, Kevin W.; Henderson, Brenda S.; Haskin, Harry H.

    2005-01-01

    An experimental investigation of flow conditioning devices used to suppress internal rig noise in high speed, high temperature experimental jet facilities is discussed. The aerodynamic and acoustic characteristics of a number of devices including pressure loss and extraneous noise generation are measured. Both aerodynamic and acoustic characteristics are strongly dependent on the porosity of the flow conditioner and the closure ratio of the duct system. For unchoked flow conditioners, the pressure loss follows conventional incompressible flow models. However, for choked flow conditioners, a compressible flow model where the duct and flow conditioner system is modeled as a convergent-divergent nozzle can be used to estimate pressure loss. Choked flow conditioners generate significantly more noise than unchoked conditioners. In addition, flow conditioners with small hole diameters or sintered metal felt material generate less self-noise noise compared to flow conditioners with larger holes.

  3. The Ethics of Testing a Test: Randomized Trials of the Health Impact of Diagnostic Tests for Infectious Diseases

    PubMed Central

    Dowdy, David W.; Gounder, Celine R.; Corbett, Elizabeth L.; Ngwira, Lucky G.; Chaisson, Richard E.; Merritt, Maria W.

    2012-01-01

    In the last decade, many new rapid diagnostic tests for infectious diseases have been developed. In general, these new tests are developed with the intent to optimize feasibility and population health, not accuracy alone. However, unlike drugs or vaccines, diagnostic tests are evaluated and licensed on the basis of accuracy, not health impact (eg, reduced morbidity or mortality). Thus, these tests are sometimes recommended or scaled up for purposes of improving population health without randomized evidence that they do so. We highlight the importance of randomized trials to evaluate the health impact of novel diagnostics and note that such trials raise distinctive ethical challenges of equipoise, equity, and informed consent. We discuss the distinction between equipoise for patient-important outcomes versus diagnostic accuracy, the equity implications of evaluating health impact of diagnostics under routine conditions, and the importance of offering reasonable choices for informed consent in diagnostic trials. PMID:22918990

  4. The ethics of testing a test: randomized trials of the health impact of diagnostic tests for infectious diseases.

    PubMed

    Dowdy, David W; Gounder, Celine R; Corbett, Elizabeth L; Ngwira, Lucky G; Chaisson, Richard E; Merritt, Maria W

    2012-12-01

    In the last decade, many new rapid diagnostic tests for infectious diseases have been developed. In general, these new tests are developed with the intent to optimize feasibility and population health, not accuracy alone. However, unlike drugs or vaccines, diagnostic tests are evaluated and licensed on the basis of accuracy, not health impact (eg, reduced morbidity or mortality). Thus, these tests are sometimes recommended or scaled up for purposes of improving population health without randomized evidence that they do so. We highlight the importance of randomized trials to evaluate the health impact of novel diagnostics and note that such trials raise distinctive ethical challenges of equipoise, equity, and informed consent. We discuss the distinction between equipoise for patient-important outcomes versus diagnostic accuracy, the equity implications of evaluating health impact of diagnostics under routine conditions, and the importance of offering reasonable choices for informed consent in diagnostic trials.

  5. 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.

  6. 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.

  7. Key nasal symptoms predicting a positive skin test in allergic rhinitis and patient characteristics according to ARIA classification.

    PubMed

    Chaiyasate, Saisawat; Roongrotwattanasiri, Kannika; Fooanant, Supranee; Sumitsawan, Yupa

    2009-03-01

    To find predicting symptom(s) in patients with a positive skin test, and identify patient characteristics according to ARIA classification. Four hundred and thirty four rhinologic patients were retrospectively studied. Nasal obstruction, rhinorrhea, itching, sneezing, and smell dysfunction were assessed. Patients were also classified according to the ARIA guideline. Of 434 patients, 277 (63.8%) were skin prick test positive. There was no statistical difference in sex, but the mean age of the positive skin test group was lower than that in the negative group (p < 0.05). Intermittent or persistent symptoms and total symptom score were not significantly different. Severe nasal itching was more common in the positive group (p = 0.04). The impact of symptoms was similar between the two groups, except for self-reported comorbidity, which was higher in the negative group (p = 0.039). There were no predicting symptoms and no difference in the symptom characteristics for the patients with positive skin test.

  8. 49 CFR 325.53 - Site characteristics; stationary test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... MOTOR CARRIER NOISE EMISSION STANDARDS Measurement of Noise Emissions; Stationary Test § 325.53 Site...) Traffic railings of any type of construction except solid concrete barriers (see § 325.5(c)(4)). (4) One...

  9. Impact of Laboratory Test Use Strategies in a Turkish Hospital.

    PubMed

    Yılmaz, Fatma Meriç; Kahveci, Rabia; Aksoy, Altan; Özer Kucuk, Emine; Akın, Tezcan; Mathew, Joseph Lazar; Meads, Catherine; Zengin, Nurullah

    2016-01-01

    Eliminating unnecessary laboratory tests is a good way to reduce costs while maintain patient safety. The aim of this study was to define and process strategies to rationalize laboratory use in Ankara Numune Training and Research Hospital (ANH) and calculate potential savings in costs. A collaborative plan was defined by hospital managers; joint meetings with ANHTA and laboratory professors were set; the joint committee invited relevant staff for input, and a laboratory efficiency committee was created. Literature was reviewed systematically to identify strategies used to improve laboratory efficiency. Strategies that would be applicable in local settings were identified for implementation, processed, and the impact on clinical use and costs assessed for 12 months. Laboratory use in ANH differed enormously among clinics. Major use was identified in internal medicine. The mean number of tests per patient was 15.8. Unnecessary testing for chloride, folic acid, free prostate specific antigen, hepatitis and HIV testing were observed. Test panel use was pinpointed as the main cause of overuse of the laboratory and the Hospital Information System test ordering page was reorganized. A significant decrease (between 12.6-85.0%) was observed for the tests that were taken to an alternative page on the computer screen. The one year study saving was equivalent to 371,183 US dollars. Hospital-based committees including laboratory professionals and clinicians can define hospital based problems and led to a standardized approach to test use that can help clinicians reduce laboratory costs through appropriate use of laboratory tests.

  10. Impact of weekly feedback on test ordering patterns.

    PubMed

    Minerowicz, Christine; Abel, Nicole; Hunter, Krystal; Behling, Kathryn C; Cerceo, Elizabeth; Bierl, Charlene

    2015-11-01

    We examined the impact of weekly feedback reports on the test-ordering behavior of internal medicine residents. Retrospective analysis of a performance improvement effort. In a large, urban, academic medical center, we extracted raw data on every inpatient laboratory test ordered by all internal medicine residents during two 26-week time periods. The pre-intervention phase established baseline ordering volume as each resident rotated through the various clinical services. The intervention consisted of a 1-hour educational seminar detailing the potential harm and costs of laboratory overutilization followed by the post intervention phase, which consisted of weekly feedback reports graphically illustrating individual versus group ordering patterns, where the identity of individual residents was protected. The total numbers of tests ordered during the 2 phases were compared using an independent t test. During the post intervention phase, we observed a net reduction of 21% in tests ordered-an average of 941 tests per week-with the greatest reduction in the chemistry section of the laboratory, followed by hematology, coagulation, and all others combined. This reduction in test volume corresponded to a $1.3 million reduction in charges. Providing physicians-in-training with a weekly feedback report detailing their test ordering volume in comparison with those of their peers is an effective method for reducing laboratory overutilization. Benefits to our approach include maintaining physician autonomy without alteration of existing infrastructure or disclosure of test fees.

  11. 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.

  12. The Impact of Inmate and Prison Characteristics on Prisoner Victimization.

    PubMed

    Steiner, Benjamin; Ellison, Jared M; Butler, H Daniel; Cain, Calli M

    2017-01-01

    A considerable amount of research has been directed at understanding the sources of inmate misconduct (offending within prison), whereas few studies have focused on identifying the causes and correlates of prisoner victimization. The sources of inmate victimization should be distinguished from those of offending, however, because the policy implications of each focus differ to some extent. In order to determine the predictors of inmate victimization and stimulate further research on the topic, we systematically reviewed studies of the causes/correlates of prisoner victimization published between 1980 and 2014. Our findings revealed that predictor variables reflecting inmates' background characteristics (e.g., history of victimization), their institutional routines and experiences (e.g., history of misconduct), and prison characteristics (e.g., population size) all influence victimization. © The Author(s) 2015.

  13. 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.

  14. Psychosocial impact of predictive testing for myotonic dystrophy type 1.

    PubMed

    Prévost, Claude; Veillette, Suzanne; Perron, Michel; Laberge, Claude; Tremblay, Carmen; Auclair, Julie; Villeneuve, Josée; Tremblay, Marc; Mathieu, Jean

    2004-04-01

    In the Saguenay-Lac-Saint-Jean region (Quebec, Canada), a predictive DNA-testing program for myotonic dystrophy type 1 (DM1) has been available as a clinical service since 1988. From 1 to 12 years (median, 5 years) after receiving predictive testing, a total of 308 participants (44 carriers and 264 non-carriers) answered a questionnaire to determine the psychosocial impact of this genetic testing. The main reasons for wanting to be tested were to learn if children are at risk for DM1 or for reproductive decision making (75%) and to relieve the uncertainty for themselves (17%). The majority of participants (96.1%) remembered correctly their test result. At the time of the survey, the perception of the general well-being, the psychological distress (Psychiatric Symptom Index), and the self-esteem (Rosenberg Self-Esteem Scale) were similar in carriers, in non-carriers, and in the reference (Quebec) population. When participants indicated a change in different aspects of their lives following predictive testing, it was perceived as a change for the better by non-carriers and as a change for the worse by carriers. Nevertheless, for a majority of carriers and of non-carriers, the test result did not bring changes in their lives. All respondents believed that predictive testing should be available for the at-risk population and the vast majority of carrier and of non-carriers would recommend the use of predictive testing to their family members. Predictive testing for individuals at-risk of DM1 can be offered safely within a well-organized clinical and genetic counseling program that includes careful pre-test counseling, pre-test clinical assessment, post-test psychological support, and follow-up for those identified as carriers. Copyright 2003 Wiley-Liss, Inc.

  15. 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.

  16. Flash characteristics of plasma induced by hypervelocity impact

    SciTech Connect

    Zhang, Kai; Long, Renrong E-mail: qmzhang@bit.edu.cn; Zhang, Qingming E-mail: qmzhang@bit.edu.cn; Xue, Yijiang; Ju, Yuanyuan

    2016-08-15

    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.

  17. 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

  18. Discovering the impact of preceding units' characteristics on the wait time of cardiac surgery unit from statistic data.

    PubMed

    Liu, Jiming; Tao, Li; Xiao, Bo

    2011-01-01

    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). 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 show that: (i) wait time of CU has a direct positive impact on wait time of SU (β = 0.330, p < 0.01); (ii) capacity of CU has a direct positive impact on demand of SU (β = 0.644, p < 0.01); (iii) within each unit, there exist significant relationships among different characteristics (except for the effect of throughput on wait time in SU). 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.

  19. 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.

  20. 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.

  1. Radioisotope thermoelectric generator/thin fragment impact test

    SciTech Connect

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

    1998-01-01

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

  2. Radioisotope thermoelectric generator/thin fragment impact test

    SciTech Connect

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

    1998-01-15

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

  3. 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.

  4. Relationship between echotextural and histomorphometric characteristics of stallion testes.

    PubMed

    Pozor, Malgorzata; Morrissey, Heather; Albanese, Valeria; Khouzam, Natalie; Deriberprey, Alexis; Macpherson, Margo L; Kelleman, Audrey A

    2017-09-01

    The goal of this study was to investigate correlations between objective measures of testicular echotexture and histomorphometric attributes related to the histological composition of stallion testes. Fifty-four scrotal testes were obtained from three groups of stallions during routine castrations: colts <1 yr old (n = 18), young stallions 1-5 yrs old (n = 27), mature stallions > 5 yrs old (n = 9). In addition, two scrotal testes with degeneration, 16 retained inguinal and 10 retained abdominal testes were surgically obtained. Cross-sectional and longitudinal ultrasonograms were obtained for each testis. Mean numerical pixel values (NPVs) as well as pixel standard deviations (PSDs) were determined for each image (ImageJ-1.5 software). Histomorphometric attributes of the seminiferous tubules (STs) were derived (three tissue samples per each testis) using image analysis software [relative STs area: RSTA = ST area/total cross-sectional area (TA) x 100%; relative STs lumen: RSTL = ST lumen area/TA x 100%; individual ST area; ISTA; individual ST lumen: ISTL; seminiferous epithelium height: SHE]. Degree of fibrosis was graded semi-quantitatively (0-3) in samples from 17 testes. All measures of testicular echotexture as well as all histomorphometric attributes of STs had highest values when obtained from the scrotal testes of young and mature stallions (P < 0.05). The NPVs and PSDs from the ultrasonographic images of the scrotal testes were significantly correlated with all histomorphometric attributes of STs (P < 0.001). However, there was no correlation between the majority of these measures and attributes if each group of the scrotal testes was analyzed separately. The NPVs from the ultrasonographic images of the retained inguinal testes were correlated with RSTA, RSTL, ISTA, and ISTL, while the NPVs from the retained abdominal testes were not correlated with any of the histomorphometric attributes of the STs. Testes with high degree of fibrosis had

  5. 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.

  6. 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.

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

    PubMed

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

    2014-08-01

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

  8. 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.

  9. 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.

  10. Measures of the risk impacts of testing and maintenance activities

    SciTech Connect

    Vesely, W.E.; Davis, T.C.; Saltos, N.

    1983-11-01

    This report is a companion to Measures of Risk Importance and Their Applications (NUREG/CR-3385). This report focuses on quantifying the importance of online tests, maintenances, repairs in controlling the risk. The importance measures which are defined are applied to evaluate the corrective and preventative benefits of online testing, maintenance, and repair. The corrective and preventative benefits are measured in terms of the impacts in risk which result. The corrective value of a repair or unscheduled maintenance action is termed the restoration worth of the action and is defined to be the reduction in risk which results from restoring a failed component or system. The preventative value of a test or maintenance action is termed the expected worth of the action and is defined to be the expected risk reduction from performing the action. There is a great deal of information obtainable from these kinds of measures which can be simply calculated in any PRA and enhance the usefulness of the PRA. If there is a general message from this work regarding risk assurance programs and inspection programs it is on the usefulness of risk analysis techniques in these programs. To be most effective with regard to risk control inspection programs and risk assurance programs directed at testing and maintenance should be guided by the risk impacts of the test or maintenance.

  11. 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.

  12. 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

  13. Understanding the impact of genetic testing for inherited retinal dystrophy

    PubMed Central

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

    2013-01-01

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

  14. 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.

  15. 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.

  16. Fibromyalgia Impact and Mindfulness Characteristics in 4986 People with Fibromyalgia.

    PubMed

    Jones, Kim D; Mist, Scott D; Casselberry, Marie A; Ali, Ather; Christopher, Michael S

    2015-01-01

    A growing body of literature suggests that mindfulness techniques may be beneficial in fibromyalgia. A recent systematic review and meta-analysis of six trials indicated improvement in depressive symptoms and quality of life, calling for increased rigor and use of standardized measures in future trials. The purpose of the study was to examine the relationship between mindfulness [as measured by the Five Facet Mindfulness Questionnaire (FFMQ)] and fibromyalgia impact [as measured by the Revised Fibromyalgia Impact Questionnaire (FIQR)]. A cross-sectional survey was conducted with adults diagnosed with fibromyalgia from a national fibromyalgia advocacy foundation e-mail list. A total of 4986 respondents represented all 50 states in the United States and 30 countries. FIQR scores demonstrated moderate to severe fibromyalgia with the majority of subjects (59%) scoring ≤60. Scores on the FFMQ subscales ranged from 20.8 to 27.3, with highest scores for the observe subscale. All subscale correlations were small to moderate and indicated that more severe fibromyalgia impact was associated with less mindfulness except in the observe scale (r = .15, P > .000). No clinical or demographics explained as much variance in the FIQR total as any of the mindfulness subscales. Fibromyalgia patients experience symptoms that may be alleviated by mindfulness interventions. Baseline values for the observe subscale of the FFMQ were unexpectedly high. Further research is needed to know if this may be due to non-mindful observations and should be noted when the FFMQ is used in fibromyalgia clinical trials. Copyright © 2015. Published by Elsevier Inc.

  17. Fibromyalgia Impact and Mindfulness Characteristics in 4986 People with Fibromyalgia

    PubMed Central

    Jones, Kim D.; Mist, Scott D.; Casselberry, Marie A.; Ali, Ather; Christopher, Michael S.

    2015-01-01

    Context and Objective A growing body of literature suggests that mindfulness techniques may be beneficial in fibromyalgia. A recent systematic review and meta-analysis of six trials indicated improvement in depressive symptoms and quality of life, calling for increased rigor and use of standardized measures in future trials. The purpose of the study was to examine the relationship between mindfulness [as measured by the Five Facet Mindfulness Questionnaire (FFMQ)] and fibromyalgia impact [as measured by the Revised Fibromyalgia Impact Questionnaire (FIQR)]. Design, Setting, and Participants A cross-sectional survey was conducted with adults diagnosed with fibromyalgia from a national fibromyalgia advocacy foundation e-mail list. Results A total of 4986 respondents represented all 50 states in the United States and 30 countries. FIQR scores demonstrated moderate to severe fibromyalgia with the majority of subjects (59%) scoring ≤60. Scores on the FFMQ subscales ranged from 20.8 to 27.3, with highest scores for the observe subscale. All subscale correlations were small to moderate and indicated that more severe fibromyalgia impact was associated with less mindfulness except in the observe scale (r = .15, P > .000). No clinical or demographics explained as much variance in the FIQR total as any of the mindfulness subscales. Conclusions Fibromyalgia patients experience symptoms that may be alleviated by mindfulness interventions. Baseline values for the observe subscale of the FFMQ were unexpectedly high. Further research is needed to know if this may be due to non-mindful observations and should be noted when the FFMQ is used in fibromyalgia clinical trials. PMID:26005199

  18. Dust impact on the geometrical characteristics of an axial compressor

    NASA Astrophysics Data System (ADS)

    Katarína, Ratkovská; Marián, Hocko

    2017-09-01

    This article focuses on the results of the research on the wear of air turbo-compressor engine blades operated in a dusty environment. In detail, the mechanism of the dust influence on the geometric characteristics of the axial compressor blades is discussed. De-pending on the operating time of the engine, basic laws on the dimensions of the wear of the blades in different degrees of the axial compressor are mentioned. Based on the experimental results, the possibilities of modeling the erosive wear of compressor blades are solved.

  19. Impact of collisionality on fluctuation characteristics of micro-turbulence

    SciTech Connect

    Vermare, L.; Hennequin, P.; Guercan, Oe. D.; Bourdelle, C.; Clairet, F.; Garbet, X.; Sabot, R.

    2011-01-15

    The influence of changing collisionality on density fluctuation characteristics is studied during dedicated {nu}* scaling experiments, using Doppler backscattering system. First, the repartition of fluctuation energy over different spatial scales, as represented by the wavenumber spectrum, is investigated and a modification of the shape of the perpendicular wavenumber spectrum in the low wavenumber part of the spectrum is observed when changing collisionality. In addition, a new procedure to evaluate the dispersion relation of micro-turbulence is presented. From the behavior of the perpendicular mean velocity of density fluctuations with the perpendicular wavenumber, different dispersion relations are obtained between low and high collisionality cases.

  20. Communicating minimum impact behavior with trailside bulletin boards: Visitor characteristics associated with effectiveness

    Treesearch

    Stephen F. McCool; David N. Cole

    2000-01-01

    Bulletin boards are a frequently used method of communicating minimum impact behaviors to wilderness visitors. But how effective are they? What types of visitors are most likely to pay attention to the messages posted there? This study used a field experiment to identify visitor characteristics associated with attention to minimum impact messages posted on a bulletin...

  1. Impact of genetic testing for breast-ovarian cancer susceptibility.

    PubMed

    Loader, Starlene; Shields, Cleveland G; Rowley, Peter T

    2004-01-01

    Previously, we have reported a clinical trial in which any woman in a defined geographic region who had a qualifying family history and who was referred by her physician or who was identified through a regional cancer registry was offered free genetic counseling, BRCA testing, and recommendations based on test results. Each family was represented by one affected and one unaffected person. Of the 87 families actually tested, 13 were found to have deleterious mutations. To assess the impact of the counseling and testing process, we contacted the tested individuals 1 month and 1 year after receiving the test result and those with an abnormal test result after 4 years. Index subjects, we found, differed significantly from relatives. Before coming for counseling, index subjects perceived both their general health and emotional health as worse than did their relatives. After counseling and testing, index subjects continue to worry more about breast cancer than do relatives. Affected subjects, we found, differed significantly from unaffected subjects. Before counseling, affected subjects knew more about breast cancer, perceived their general health as poorer, and reported greater adherence to recommended breast cancer surveillance than did unaffected subjects. After counseling and testing, affected subjects were less satisfied than unaffected subjects with having been tested. This study indicates that the group most prone to distress by cancer risk genetic counseling and testing is not the recruited relatives, nor even those affected with cancer, but rather the index patients themselves. The index patients, i.e., the ones who want the risk information most, appear to undergo the most stress in obtaining it.

  2. Impact of a government triple zero awareness campaign on emergency department patient characteristics.

    PubMed

    Hou, Xiang-Yu; Zhao, Jingzhou; Chu, Kevin

    2012-08-01

    To evaluate the impact of a government triple zero community awareness campaign on the characteristics of patients attending an ED. A study using Emergency Department Information System data was conducted in an adult metropolitan tertiary-referral teaching hospital in Brisbane. The three outcomes measured in the 3 month post-campaign period were arrival mode, Australasian Triage Scale and departure status. These measures reflect ambulance usage, clinical urgency and illness severity, respectively. They were compared with those in the 3 month pre-campaign period. Multivariate logistic regression models were used to investigate the impacts of the campaign on each of the three outcome measures after controlling for age, sex, day and time of arrival, and daily minimum temperature. There were 17,920 visits in the pre- and 17,793 visits in the post-campaign period. After the campaign, fewer patients arrived at the ED by road ambulance (odds ratio [OR] 0.90, 95% confidence interval [CI] 0.80-1.00), although the impact of the campaign on the arrival mode was only close to statistical significance (Wald χ(2) -test, P= 0.055); and patients were significantly less likely to have higher clinical urgency (OR 0.86, 95% CI 0.79-0.94), while more likely to be admitted (OR 1.68, 95% CI 1.38-2.05) or complete treatment in the ED (OR 1.46, 95% CI 1.23-1.73) instead of leaving without waiting to be seen. The campaign had no significant impact on the arrival mode of the patients. After the campaign, the illness acuity of the patients decreased, whereas the illness severity of the patients increased. © 2012 The Authors. EMA © 2012 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

  3. 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.

  4. Promoting appropriate genetic testing: the impact of a combined test review and consultative service.

    PubMed

    Suarez, Carlos J; Yu, Linbo; Downs, Natalie; Costa, Helio A; Stevenson, David A

    2017-09-01

    Genetic test misorders can adversely affect patient care. However, little is known about the types of misorders and the overall impact of a utilization management (UM) program on curbing misorders. This study aimed to identify different types of misorders and analyze the impact of a combined test review and consultative service on reducing misorders over time. Selected genetic tests were systematically reviewed between January and December 2015 at Stanford Health Care. Misorders were categorized into five types: clerical errors, redundant testing, better alternatives, controversial, and uncategorized. Moreover, consultations were offered to help clinicians with test selection. Of the 629 molecular test orders reviewed, 13% were classified as misorders, and 7% were modified or canceled. Controversial misorders constitute the most common type (42%); however, unlike the other misorder types, they were negligibly affected by test review. Simultaneously, 71 consults were received. With the introduction of the UM program, genetic test misorders went from 22% at baseline to 3% at the end of the year. Our results show that the combined approach of test review and consultative service effectively reduced misorders over time and suggest that a UM program focused on eliminating misorders can positively influence health-care providers' behaviors.Genet Med advance online publication 26 January 2017.

  5. Project W-314 Polyurea Special Protective Coating (SPC) Test Plan Chemical Compatibility and Physical Characteristics Testing

    SciTech Connect

    MAUSER, R.W.

    2001-01-15

    This Test Plan outlines the testing to be done on the Special Protective Coating (SPC) Polyurea which includes: Tank Waste Compatibility, Decontamination Factor Testing, and Adhesion Strength Testing after a sample has been exposed to Radiation.

  6. 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.

  7. 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.

  8. 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.

  9. Compression-after-impact testing of thin composite materials

    NASA Technical Reports Server (NTRS)

    Nettles, Alan T.; Hodge, Andrew J.

    1991-01-01

    A new method has been devised to test composite specimens as thin as 8 plies and up to 7.6 cm in width for compression strength. This method utilizes a fixture incorporating the best features of the Celanese and IITRI fixtures combined with an antibuckling jig developed at the University of Dayton Research Institute. This new method uses up to 83 percent less material than the most commonly used compression-after-impact technique (which calls for a 48 ply test specimen) and can also be performed on smaller loading frames since a much smaller force is needed to fail the specimen. The thickness of the test specimen can be fabricated to exactly match production part thickness, thus yielding more meaningful results. CAI tests were performed on IM6/3501 carbon/epoxy utilizing this new method. To verify the design, a series of tests were performed in which undamaged specimens were tested using the new fixture and ASTM D 3410-87 (Celanese compression test) and the results compared. The new fixture works well and will be a valuable asset to MSFC's damage tolerance program.

  10. 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.

  11. Characteristics of vestibulosensory reactions studied by experimental caloric test

    NASA Technical Reports Server (NTRS)

    Kapranov, V. Z.

    1980-01-01

    Vestibulo-sensory reactions were studied in 135 workers who were in contact with nitroethers, by the method of an experimental caloric test. The response vestibulo-sensory reactions were recorded by means of an electroencephalograph. The changes in the sensory reaction depended on the duration of the workers' contact with toxic agents. A study of illusion reactions by the labyrinth calorization widens diagnostic possibilities in the examination of functional condition of the vestibular analyser considerably.

  12. 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.

  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. 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.

  15. Large-event medicine--event characteristics impacting medical need.

    PubMed

    Moore, Riley; Williamson, Kelly; Sochor, Mark; Brady, William J

    2011-11-01

    Large events have been defined in many ways, from the vague description of a focused gathering of people to the more specific description of an event with at least 1,000 spectators and participants who are gathered at a specific location for a defined period of time. Regardless of the definition applied, the actual medical requirements vary considerably from one event to the next. The ability to predict these medical needs allows for the provision of adequate medical support. Many factors contribute to medical need at a large event, including event type, weather (particularly heat index), the presence of alcohol and / or illicit drugs, the number of participants, event duration, crowd demographics, and venue characteristics. This review will focus on the various features of large events such that the medical planner can better understand the challenge and provide adequate resource for patient care. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. 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.

  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. An evaluation of impact wrench vibration emissions and test methods.

    PubMed

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

    2008-03-01

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

  19. 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.

  20. 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

  1. 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.

  2. A Study on the Mechanical Properties and Impact-Induced Initiation Characteristics of Brittle PTFE/Al/W Reactive Materials

    PubMed Central

    Ge, Chao; Maimaitituersun, Wubuliaisan; Dong, Yongxiang; Tian, Chao

    2017-01-01

    Polytetrafluoroethylene/aluminum/tungsten (PTFE/Al/W) reactive materials of three different component mass ratios (73.5/26.5/0, 68.8/24.2/7 and 63.6/22.4/14) were studied in this research. Different from the PTFE/Al/W composites published elsewhere, the materials in our research were fabricated under a much lower sintering temperature and for a much shorter duration to achieve a brittle property, which aims to provide more sufficient energy release upon impact. Quasi-static compression tests, dynamic compression tests at room and elevated temperatures, and drop weight tests were conducted to evaluate the mechanical and impact-induced initiation characteristics of the materials. The materials before and after compression tests were observed by a scanning electron microscope to relate the mesoscale structural characteristics to their macro properties. All the three types of materials fail at very low strains during both quasi-static and dynamic compression. The stress-strain curves for quasi-static tests show obvious deviations while that for the dynamic tests consist of only linear-elastic and failure stages typically. The materials were also found to exhibit thermal softening at elevated temperatures and were strain-rate sensitive during dynamic tests, which were compared using dynamic increase factors (DIFs). Drop-weight test results show that the impact-initiation sensitivity increases with the increase of W content due to the brittle mechanical property. The high-speed video sequences and recovered sample residues of the drop-weight tests show that the reaction is initiated at two opposite positions near the edges of the samples, where the shear force concentrates the most intensively, indicating a shear-induced initiation mechanism. PMID:28772812

  3. A Study on the Mechanical Properties and Impact-Induced Initiation Characteristics of Brittle PTFE/Al/W Reactive Materials.

    PubMed

    Ge, Chao; Maimaitituersun, Wubuliaisan; Dong, Yongxiang; Tian, Chao

    2017-04-26

    Polytetrafluoroethylene/aluminum/tungsten (PTFE/Al/W) reactive materials of three different component mass ratios (73.5/26.5/0, 68.8/24.2/7 and 63.6/22.4/14) were studied in this research. Different from the PTFE/Al/W composites published elsewhere, the materials in our research were fabricated under a much lower sintering temperature and for a much shorter duration to achieve a brittle property, which aims to provide more sufficient energy release upon impact. Quasi-static compression tests, dynamic compression tests at room and elevated temperatures, and drop weight tests were conducted to evaluate the mechanical and impact-induced initiation characteristics of the materials. The materials before and after compression tests were observed by a scanning electron microscope to relate the mesoscale structural characteristics to their macro properties. All the three types of materials fail at very low strains during both quasi-static and dynamic compression. The stress-strain curves for quasi-static tests show obvious deviations while that for the dynamic tests consist of only linear-elastic and failure stages typically. The materials were also found to exhibit thermal softening at elevated temperatures and were strain-rate sensitive during dynamic tests, which were compared using dynamic increase factors (DIFs). Drop-weight test results show that the impact-initiation sensitivity increases with the increase of W content due to the brittle mechanical property. The high-speed video sequences and recovered sample residues of the drop-weight tests show that the reaction is initiated at two opposite positions near the edges of the samples, where the shear force concentrates the most intensively, indicating a shear-induced initiation mechanism.

  4. 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.

  5. Reflectance characteristics of the Viking lander camera reference test charts

    NASA Technical Reports Server (NTRS)

    Wall, S. D.; Burcher, E. E.; Jabson, D. J.

    1975-01-01

    Reference test charts provide radiometric, colorimetric, and spatial resolution references for the Viking lander cameras on Mars. Reflectance measurements of these references are described, including the absolute bidirectional reflectance of the radiometric references and the relative spectral reflectance of both radiometric and colorimetric references. Results show that the bidirection reflectance of the radiometric references is Lambertian to within + or - 7% for incidence angles between 20 deg and 60 deg, and that their spectral reflectance is constant with wavelength to within + or - 5% over the spectral range of the cameras. Estimated accuracy of the measurements is + or - 0.05 in relative spectral reflectance.

  6. 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…

  7. 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.

  8. Impact of Laboratory Test Use Strategies in a Turkish Hospital

    PubMed Central

    Yılmaz, Fatma Meriç; Kahveci, Rabia; Aksoy, Altan; Özer Kucuk, Emine; Akın, Tezcan; Mathew, Joseph Lazar; Meads, Catherine; Zengin, Nurullah

    2016-01-01

    Objectives Eliminating unnecessary laboratory tests is a good way to reduce costs while maintain patient safety. The aim of this study was to define and process strategies to rationalize laboratory use in Ankara Numune Training and Research Hospital (ANH) and calculate potential savings in costs. Methods A collaborative plan was defined by hospital managers; joint meetings with ANHTA and laboratory professors were set; the joint committee invited relevant staff for input, and a laboratory efficiency committee was created. Literature was reviewed systematically to identify strategies used to improve laboratory efficiency. Strategies that would be applicable in local settings were identified for implementation, processed, and the impact on clinical use and costs assessed for 12 months. Results Laboratory use in ANH differed enormously among clinics. Major use was identified in internal medicine. The mean number of tests per patient was 15.8. Unnecessary testing for chloride, folic acid, free prostate specific antigen, hepatitis and HIV testing were observed. Test panel use was pinpointed as the main cause of overuse of the laboratory and the Hospital Information System test ordering page was reorganized. A significant decrease (between 12.6–85.0%) was observed for the tests that were taken to an alternative page on the computer screen. The one year study saving was equivalent to 371,183 US dollars. Conclusion Hospital-based committees including laboratory professionals and clinicians can define hospital based problems and led to a standardized approach to test use that can help clinicians reduce laboratory costs through appropriate use of laboratory tests. PMID:27077653

  9. The impact of commercial rapid respiratory virus diagnostic tests on patient outcomes and health system utilization.

    PubMed

    Ko, Fiona; Drews, Steven J

    2017-10-01

    Acute respiratory tract infections due to influenza A/B and respiratory syncytial virus (RSV) are major causes of morbidity and mortality globally. Rapid tests for detection of these pathogens include antigen detection point of care tests (POC) and newer easy to use molecular tests. From experience, these assays improve both laboratory workflow and assay interpretation issues. However, the question of the benefits of using rapid test technology compared to routine laboratory testing for respiratory viral pathogens is still often asked. Areas covered: Specifically, this review aims to; 1) identify clinical/patient indicators that can be measured prior to and following the implementation of rapid diagnostic test for influenza and RSV, 2) provide multiple perspectives on the extent of impact of a rapid diagnostic test, including direct and indirect outcomes, and 3) identify the technological advancements in the development of rapid testing, demonstrating a timeline that transitions from antigen-based assays to molecular assays. Expert commentary: Key benefits to the use of either antigen-based or molecular rapid tests for patient care, patient flow within institutions, as well as laboratory utilization are identified. Due to improved test characteristics, the authors feel that rapid molecular tests have greater benefits than antigen-based detection methods.

  10. 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.

  11. Impact of Asphaltenes and Resins on the Wetting Characteristics of Tars at Former Manufactured Gas Plants

    NASA Astrophysics Data System (ADS)

    Hauswirth, S. C.; Birak, P. S.; Rylander, S.; Pedit, J. A.; Miller, C. T.

    2008-12-01

    Tars produced as a byproduct of coal and oil gasification at manufactured gas plants (MGPs) during the 19th and early 20th centuries were often released into the environment through poor disposal practices or leaks in holding tanks and piping. These tars are persistent contaminants, leaching polycyclic aromatic hydrocarbons (PAHs) into groundwater and posing a significant risk to human and ecological health. MGP tars also have several properties that make them notoriously difficult to remediate. They are denser than water, so they can migrate to depths which make direct removal difficult or impossible, and their relatively high viscosities and ability to alter the wetting characteristics of porous media result in inefficient removal by traditional pump-and-treat methods. In this study, we investigate the last of these properties. Previous studies have linked wetting changes to asphaltenes---polar, high molecular weight compounds present in the tars. However, we have conducted qualitative bottle tests for tar samples collected from two former MGPs which indicate that there is no direct correlation between asphaltene concentration and the tendency to alter wetting characteristics of porous media. To better understand the factors controlling wetting behavior, we isolate asphaltenes and resins, another class of polar compounds, from a tar sample and recombine them with the remaining PAH mixture to create a series of tars of varying composition. We assess the relative impact of each of the fractions on wettability through contact angle measurements conducted at three different pHs.

  12. 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

  13. 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.

  14. Characteristics of future aircraft impacting aircraft and airport compatibility

    NASA Technical Reports Server (NTRS)

    Conner, D. W.

    1982-01-01

    Results are reported of an opinion survey of selected individuals at the decision-making level within the five major manufacturers of transport aircraft in the United States and Europe. Opinions were obtained concerning both possible and probable existence of over 50 compatibility-related characteristics of transport aircraft in use in the years 1990, 2000, and 2010. The maximum size of aircraft is expected to increase, at a roughly uniform rate, to the year 2010 by 85 percent in passengers, 55 percent in airfreighter payload, and 35 percent in gross weight weight. Companion to the expected growth in payloads and gross weight was the identification of probable increases in aircraft geometrical dimensions and component capability, and use of fully double-decked passenger compartments. Wing span will increase considerably more than normally expected to provide wings of higher aspect ratio. New aircraft features coming into probable use include large turboprops, synthetic jet-A fuel, winglets, wake-vortex-reducing devices and laminar flow control. New operational concepts considered probable include steep approaches, high-speed turnoffs, and taxiway towing for the aircraft, plus passenger bypass of the terminal building, expedited handling of belly cargo and an intermodal cargo container for the payloads.

  15. 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.

  16. Racial Differences in Clinical Characteristics, Perceptions and Behaviors, and Psychosocial Impact of Adult Female Acne

    PubMed Central

    Alexis, Andrew F.; Daniels, Selena R.; Kawata, Ariane K.; Burk, Caroline T.; Wilcox, Teresa K.; Taylor, Susan C.

    2014-01-01

    Objective: Limited data are available on racial differences in clinical characteristics and burden in adult female acne. The objective was to describe racial differences in clinical characteristics, psychosocial impact, perceptions, behaviors, and treatment satisfaction in facial adult female acne. Design: Cross-sectional, web-based survey. Setting: Diverse sample of United States women. Participants: Women between the ages of 25 and 45 years with facial acne (≥25 visible lesions). Measurements: Outcomes included sociodemographic characteristics, psychosocial impacts, perceptions, behaviors, and treatment satisfaction. Racial differences were evaluated using descriptive statistics and t-test/chi-square analyses. Results: 208 females participated (mean age 35±6 years); 51.4 percent were White/Caucasian and 48.6 percent were non-White/Caucasian women [Black/African American (n=51); Hispanic/Latina (n=23); Asian (n=16); Other (n=ll)]. Age of acne onset (mean 14.8±5 vs. 17.0±8 years, p<0.05) and acne concern occurred earlier (16.6±7 vs. 19.3±9 years, p<0.05) in White/Caucasian than non-White/Caucasian subjects. Facial acne primarily presented on chin (28.0%) and cheeks (30.8%) for White/Caucasian women versus cheeks (58.4%) for non-White/Caucasian women. Non-White/Caucasian women experienced more postinflammatory hyperpigmentation than White/Caucasian women (p<0.0001). Facial acne negatively affected quality of life (QoL) in both groups, and most participants (>70%) reported some depression/anxiety symptoms. More White/Caucasian than non-White/Caucasian women were troubled by facial acne (88.8% vs. 76.2%, p<0.05). Lesion clearance was most important to White/Caucasian women (57.9 vs. non-White/Caucasian 31.7%, p<0.001); non-White/Caucasian females focused on postinflammatory hyperpigmentation clearance (41.6% vs. Caucasian 8.4%, p<0.0001). Conclusion: Results highlight racial differences in participant-reported clinical characteristics, attitudes, behaviors, and

  17. Utility of the ImPACT test with deaf adolescents.

    PubMed

    Reesman, Jennifer; Pineda, Jill; Carver, Jenny; Brice, Patrick J; Zabel, T Andrew; Schatz, Philip

    2016-02-01

    The goals of the study included empirical examination of the utility of the Immediate and Post-Concussion Assessment and Cognitive Testing (ImPACT) test with adolescents who are deaf or hard-of-hearing and to investigate patterns of performance at baseline that may arise in the assessment of this population. Baseline assessment of student-athletes has been conducted on a widespread scale with focus on performance of typically developing student-athletes and some clinical groups, though to date no studies have examined adolescents who are deaf or hard-of-hearing. Retrospective and de-identified ImPACT baseline test used with deaf and hard-of-hearing high-school student-athletes (N = 143; 66% male, mean age = 16.11) was examined. Review indicated significant differences in some composite scores between the deaf and hard-of-hearing group and hearing normative comparisons. A possible marker of task misunderstanding was identified to occur more frequently within the deaf and hard-of-hearing sample (13% in deaf sample vs. .31% in hearing sample). Results may provide support for the consideration and use of additional measures to ensure comprehension of task demands when considering this tool for use with deaf and hard-of-hearing adolescents.

  18. 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.

  19. 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

  20. 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…

  1. 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…

  2. 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.

  3. Player and Game Characteristics and Head Impacts in Female Youth Ice Hockey Players.

    PubMed

    Reed, Nick; Taha, Tim; Greenwald, Richard; Keightley, Michelle

    2017-08-01

      Despite the growing popularity of ice hockey among female youth and interest in the biomechanics of head impacts in sport, the head impacts sustained by this population have yet to be characterized.   To describe the number of, biomechanical characteristics of, and exposure to head impacts of female youth ice hockey players during competition and to investigate the influences of player and game characteristics on head impacts.   Cohort study.   Twenty-seven female youth ice hockey players (mean age = 12.5 ± 0.52 years) wore instrumented ice hockey helmets during 66 ice hockey games over a 3-year period. Data specific to player, game, and biomechanical head impact characteristics were recorded. A multiple regression analysis identified factors most associated with head impacts of greater frequency and severity.   A total of 436 total head impacts were sustained during 6924 minutes of active ice hockey participation (0.9 ± 0.6 impacts per player per game; range, 0-2.1). A higher body mass index (BMI) significantly predicted a higher number of head impacts sustained per game (P = .008). Linear acceleration of head impacts was greater in older players and those who played the forward position, had a greater BMI, and spent more time on the ice (P = .008), whereas greater rotational acceleration was present in older players who had a greater BMI and played the forward position (P = .008). During tournament games, increased ice time predicted increased severity of head impacts (P = .03).   This study reveals for the first time that head impacts are occurring in female youth ice hockey players, albeit at a lower rate and severity than in male youth ice hockey players, despite the lack of intentional body checking.

  4. 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

  5. Infrasound from lightning: characteristics and impact on an infrasound station

    NASA Astrophysics Data System (ADS)

    Farges, T.; Blanc, E.

    2009-12-01

    More than two third of the infrasound stations of the International Monitoring System (IMS) of the CTBTO are now certified and measure routinely signals due particularly to natural activity (swell, volcano, severe weather including lightning, …). It is well established that more than 2,000 thunderstorms are continuously active all around the world and that about 45 lightning flashes are produced per second over the globe. During the Eurosprite 2005 campaign, we took the opportunity to measure, in France during summer, infrasound from lightning and from sprites (which are transient luminous events occurring over thunderstorm). We examine the possibility to measure infrasound from lightning when thunderstorms are close or far from the infrasound station. Main results concern detection range of infrasound from lightning, amplitude vs. distance law, and characteristics of frequency spectrum. We show clearly that infrasound from lightning can be detected when the thunderstorm is within about 75 km from the station. In good noise conditions, infrasound from lightning can be detected when thunderstorms are located more than 200 km from the station. No signal is recorded from lightning flashes occurring between 75 and 200 km away from the station, defining then a silence zone. When the thunderstorm is close to the station, the infrasound signal could reach several Pascal. The signal is then on average 30 dB over the noise level at 1 Hz. Infrasound propagate upward where the highest frequencies are dissipated and can produce a significant heating of the upper mesosphere. Some of these results have been confirmed by case studies with data from the IMS Ivory Coast station. The coverage of the IMS stations is very good to study the thunderstorm activity and its disparity which is a good proxy of the global warming. Progress in data processing for infrasound data in the last ten years and the appearance of global lightning detection network as the World Wide Lightning

  6. Infrasound from lightning: characteristics and impact on an infrasound station

    NASA Astrophysics Data System (ADS)

    Farges, Thomas; Blanc, Elisabeth

    2010-05-01

    More than two third of the infrasound stations of the International Monitoring System (IMS) of the CTBTO are now certified and measure routinely signals due particularly to natural activity (swell, volcano, severe weather including lightning, …). It is well established that more than 2,000 thunderstorms are continuously active all around the world and that about 45 lightning flashes are produced per second over the globe. During the Eurosprite 2005 campaign, we took the opportunity to measure, in France during summer, infrasound from lightning and from sprites (which are transient luminous events occurring over thunderstorm). We examine the possibility to measure infrasound from lightning when thunderstorms are close or far from the infrasound station. Main results concern detection range of infrasound from lightning, amplitude vs. distance law, and characteristics of frequency spectrum. We show clearly that infrasound from lightning can be detected when the thunderstorm is within about 75 km from the station. In good noise conditions, infrasound from lightning can be detected when thunderstorms are located more than 200 km from the station. No signal is recorded from lightning flashes occurring between 75 and 200 km away from the station, defining then a silence zone. When the thunderstorm is close to the station, the infrasound signal could reach several Pascal. The signal is then on average 30 dB over the noise level at 1 Hz. Infrasound propagate upward where the highest frequencies are dissipated and can produce a significant heating of the upper mesosphere. Some of these results have been confirmed by case studies with data from the IMS Ivory Coast station. The coverage of the IMS stations is very good to study the thunderstorm activity and its disparity which is a good proxy of the global warming. Progress in data processing for infrasound data in the last ten years and the appearance of global lightning detection network as the World Wide Lightning

  7. 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.

  8. 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.

  9. Video game addiction test: validity and psychometric characteristics.

    PubMed

    van Rooij, Antonius J; Schoenmakers, Tim M; van den Eijnden, Regina J J M; Vermulst, Ad A; van de Mheen, Dike

    2012-09-01

    The study explores the reliability, validity, and measurement invariance of the Video game Addiction Test (VAT). Game-addiction problems are often linked to Internet enabled online games; the VAT has the unique benefit that it is theoretically and empirically linked to Internet addiction. The study used data (n=2,894) from a large-sample paper-and-pencil questionnaire study, conducted in 2009 on secondary schools in Netherlands. Thus, the main source of data was a large sample of schoolchildren (aged 13-16 years). Measurements included the proposed VAT, the Compulsive Internet Use Scale, weekly hours spent on various game types, and several psychosocial variables. The VAT demonstrated excellent reliability, excellent construct validity, a one-factor model fit, and a high degree of measurement invariance across gender, ethnicity, and learning year, indicating that the scale outcomes can be compared across different subgroups with little bias. In summary, the VAT can be helpful in the further study of video game addiction, and it contributes to the debate on possible inclusion of behavioral addictions in the upcoming DSM-V.

  10. 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.

  11. Impact of Complex Orography on Wake Development: Simulation Results for the Planned WindForS Test Site

    NASA Astrophysics Data System (ADS)

    Lutz, Thorsten; Schulz, Christoph; Letzgus, Patrick; Rettenmeier, Andreas

    2017-05-01

    In Southern Germany a test site will be erected in complex terrain. The purpose is to enable detailed scientific studies of terrain impact on the characteristics of two research wind turbines and to demonstrate new technologies. Within preparatory studies an appropriate site was identified and examined by field tests and numerical studies in more detail. The present paper summarizes CFD analyses on the impact of the local test site orography on the wake development of a virtual wind turbine. The effects of the orography are identified by comparative simulations for the same turbine using comparative wind situation in flat terrain.

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

    PubMed Central

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

    2000-01-01

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

  13. Biomechanical head impact characteristics during sparring practice sessions in high school taekwondo athletes.

    PubMed

    O'Sullivan, David M; Fife, Gabriel P

    2017-06-01

    OBJECTIVE The purpose of this study was to monitor head impact magnitude and characteristics, such as impact location and frequency, at high school taekwondo sparring sessions. METHODS Eight male high school taekwondo athletes participated in this study. The head impact characteristics were recorded by X-Patch, a wireless accelerometer and gyroscope, during 6 taekwondo sparring sessions. The outcome measures were the peak linear acceleration ( g = 9.81 msec(2)), peak rotational acceleration, rotational velocity, and Head Injury Criterion. RESULTS A total of 689 impacts occurred over 6 sessions involving the 8 athletes. There was an average of 24 impacts per 100 minutes, and there were significant differences in the frequency of impacts among both the sessions and individual athletes. In order of frequency, the most commonly hit locations were the side (38.2%), back (35.7%), and front (23.8%) of the head. CONCLUSIONS The data indicate that there is a relatively high number of head impacts experienced by taekwondo athletes during sparring practice. According to the rotational acceleration predicting impact severity published in previous research, 17.1% of the impacts were deemed to be a moderate and 15.5% were deemed to be severe.

  14. 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)

  15. Impact of precipitation and physical characteristics spatial variabilities on hydrological response at large catchment scale

    NASA Astrophysics Data System (ADS)

    Rouhier, Laura; Garavaglia, Federico; Le Lay, Matthieu; Le Moine, Nicolas; Ribstein, Pierre; Hendrickx, Frédéric

    2017-04-01

    The spatial variability of the hydrological response is controlled by the interaction of two spatial variabilities: (i) meteorological forcing and (ii) physical characteristics. This work aims at evaluating their relative impact on streamflow modeling throughout a catchment. To tackle the issue, a spatially distributed rainfall-runoff model, named MORDOR-TS, is used. It is a distributed version of the conceptual rainfall-runoff model currently used at Électricité de France (EDF, French electric utility company) for operational applications. The analysis is conducted at large catchment scale, on the French Loire catchment at Gien (35 707 km2) discretised at the maximum into 387 hydrological meshes of about 100km2. Within this one, 106 streamflow time series are available between 1980 and 2012. According to a spatial split-sample test scheme, the data is split into two similar parts: a calibration and a validation sample of 53 gauges each. For a model calibrated on the catchment outlet only, the impact of the rainfall pattern is assessed by testing several aggregations of the precipitation field, from uniform to mesh scale. Then, the spatial physical information is added in two steps. Firstly, the valuable information about interior gauges is taken into account by calibrating a uniform set of parameters on the whole calibration sample. Secondly, the parameters are spatialised to represent the physiographic and pedologic spatial variabilities. Dividing the catchment into sub-basins, there could be as many parameter sets calibrated as there are calibration sites. Regarding the validation sample, the worst performance is provided by a unique lumped model, while the best is given by a set of 53 independent distributed models calibrated on each validation station. The main progress from the worst towards the best case is obtained with the precipitation spatial variability (around 85% of the total progress). Interior gauges and parameters spatialisation bring some

  16. 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.

  17. A systematic evaluation of immunoassay point-of-care testing to define impact on patients' outcomes.

    PubMed

    Pecoraro, Valentina; Banfi, Giuseppe; Germagnoli, Luca; Trenti, Tommaso

    2017-07-01

    Background Point-of-care testing has been developed to provide rapid test results. Most published studies focus on analytical performance, neglecting its impact on patient outcomes. Objective To review the analytical performance and accuracy of point-of-care testing specifically planned for immunoassay and to evaluate the impact of faster results on patient management. Methods A search of electronic databases for studies reporting immunoassay results obtained in both point-of-care testing and central laboratory scenarios was performed. Data were extracted concerning the study details, and the methodological quality was assessed. The analytical characteristics and diagnostic accuracy of six points-of-care testing: troponin, procalcitonin, parathyroid hormone, brain natriuretic peptide, C-reactive protein and neutrophil gelatinase-associated lipocalin were evaluated. Results A total of 116 scientific papers were analysed. Studies measuring procalcitonin, parathyroid hormone and neutrophil gelatinase-associated lipocalin reported a limited impact on diagnostic decisions. Seven studies measuring C-reactive protein claimed a significant reduction of antibiotic prescription. Several authors evaluated brain natriuretic peptide or troponin reporting faster decision-making without any improvement in clinical outcome. Forty-four per cent of studies reported analytical data, showing satisfactory correlations between results obtained through point-of-care testing and central laboratory setting. Half of studies defined the diagnostic accuracy of point-of-care testing as acceptable for troponin (median sensitivity and specificity: 74% and 94%, respectively), brain natriuretic peptide (median sensitivity and specificity: 82% and 88%, respectively) and C-reactive protein (median sensitivity and specificity 85%). Conclusions Point-of-care testing immunoassay results seem to be reliable and accurate for troponin, brain natriuretic peptide and C-reactive protein. The satisfactory

  18. 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

  19. 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

  20. 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.

  1. 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…

  2. 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…

  3. Memory characteristics of silicon nanowire transistors generated by weak impact ionization.

    PubMed

    Lim, Doohyeok; Kim, Minsuk; Kim, Yoonjoong; Kim, Sangsig

    2017-09-29

    In this study, we demonstrate the static random access memory (SRAM) characteristics generated by weak impact ionization in bendable field-effect transistors (FETs) with n(+)-p-n(+) silicon nanowire (SiNW) channels. Our bendable SiNW FETs show not only superior switching characteristics such as an on/off current ratio of ~10(5) and steep subthreshold swing (~5 mV/dec) but also reliable SRAM characteristics. The SRAM characteristics originate from the positive feedback loops in the SiNW FETs generated by weak impact ionization. This paper describes in detail the operating mechanism of our device and demonstrates the potential of bendable SiNW FETs for future SRAM applications.

  4. 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.

  5. 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.

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

    SciTech Connect

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

    1990-01-01

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

  7. Videogame-Based Training Success: The Impact of Trainee Characteristics - Year 2

    DTIC Science & Technology

    2006-07-01

    Technical Report 1188 Videogame -Based Training Success: The Impact of Trainee Characteristics - Year 2 Karin A. Orvis George Mason University...from... to) July2006 Final December 2004-March 2006 4. TITLE AND SUBTITLE 5a. CONTRACT OR GRANT NUMBER Videogame -Based Training Success: The Impact of...Matter POC: James Belanich 14. ABSTRACT (Maximum 200 words): Personal computer (PC)-based videogames are emerging as an increasingly popular training

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Improved Bar Impact Tests Using a Photonic Doppler Velocimeter

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. The impact of eating habits on anthropometric characteristics in French primary school children.

    PubMed

    Isacco, L; Lazaar, N; Ratel, S; Thivel, D; Aucouturier, J; Doré, E; Meyer, M; Duché, P

    2010-11-01

    Obesity is increasing worldwide, reaching alarming proportions. Eating habits have changed over time and nowadays children and adolescents' environment favours the adoption of unhealthy eating behaviours leading to metabolic impairment. To explore the impact of eating risk factors and their cumulative effect on anthropometric characteristics in French primary school children. A total of 278 healthy French children (7.50 ± 0.67 years old) and their legal representatives agreed to take part in this study. Parents were asked to fill in an eating habits clinical questionnaire with questions about skipping breakfast, snacking between meals, eating in front of the TV and sugar-sweetened beverage consumption. On the basis of the answers, children were classified into four categories as a function of the number of eating risk factors they presented. Body mass index (BMI), the sum of four skinfolds (Σ4 skinfolds: tricipital, bicipital, sub-scapular and supra-iliac) and waist circumference (WC) were measured. BMI was transformed into z-BMI for each child. ANOVA and unpaired t-test provided significantly higher z-BMI, Σ4 skinfolds and WC in children who were used to skipping breakfast, snacking, watching TV while eating and consuming sugar-sweetened beverages. The more children accumulated eating risk factors, the higher were their z-BMI, Σ4 skinfolds and WC (MANOVA: P < 0.001). Eating habits appear to be associated with anthropometric characteristics in French primary school children. Anthropometric values (z-BMI, Σ4 skinfolds and WC) increased with the number of eating risk factors they presented. © 2010 Blackwell Publishing Ltd.

  4. 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.

  5. 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,…

  6. 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.

  7. 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…

  8. 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,…

  9. The Impact of Professional Development and Student and Teacher Characteristics on the Quality of Postsecondary Goals

    ERIC Educational Resources Information Center

    Doren, Bonnie; Flannery, K. Brigid; Lombardi, Allison R.; Kato, Mimi McGrath

    2013-01-01

    This study examined (a) the main effects of professional development on the quality of postsecondary goals in employment and postsecondary education/training, (b) the main effects of student and teacher characteristics on goal quality, and (c) whether professional development moderated the relationship between the impact of these characteristics…

  10. The Impact of Learner Characteristics on the Multi-Dimensional Construct of Social Presence

    ERIC Educational Resources Information Center

    Mykota, David

    2017-01-01

    This study explored the impact of learner characteristics on the multi-dimensional construct of social presence as measured by the computer-mediated communication questionnaire. Using Multiple Analysis of Variance findings reveal that the number of online courses taken and computer-mediated communication experience significantly affect the…

  11. Project W-314 Polyurea Special Protective Coating (SPC) Test Report Chemical Compatibility and Physical Characteristics Testing

    SciTech Connect

    MAUSER, R.W.

    2001-04-09

    This Engineering Test report outlines the results obtained from testing polyurea on its decon factor, tank waste compatibility, and adhesion strength when subjected to a high level of gamma radiation. This report is used in conjunction with RPP-7187 Project W-314 Pit Coatings Repair Requirements Analysis, to document the fact polyurea meets the project W-314 requirements contained in HNF-SD-W314-PDS-005 and is therefore an acceptable SPC for use in W-314 pit refurbishments.

  12. 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

  13. Characteristics of patients who accept and decline ED rapid HIV testing.

    PubMed

    Schechter-Perkins, Elissa M; Koppelman, Elisa; Mitchell, Patricia M; Morgan, Jake R; Kutzen, Randie; Drainoni, Mari-Lynn

    2014-09-01

    Understanding differences between patients who accept and decline HIV testing is important for developing methods to reduce decliner rates among patients at risk for undiagnosed HIV. The objectives of this study were to determine the rates of acceptance and reasons for declining, and to determine if differences exist in patient or visit characteristics between those who accept and decline testing. This was a retrospective medical record review of all patients offered an emergency department (ED) HIV test from 11/1/11 to 10/31/12. Patient demographic characteristics, health characteristics, and ED visit characteristics were compared to assess differences between those who accept and those who decline testing. Of 4510 ED patients offered an HIV test, 3470 accepted for an acceptance rate of 77%. The most common reasons for declining were "no perceived risk" and "tested in the last 3 months." Those who accepted testing were more likely to be unmarried, less than age 35, Hispanic or African American, Spanish speaking, foreign born, have no primary care provider, report no pain at triage, have a daytime ED visit, and be discharged from the ED compared to admitted. Sex, employment status, and ED length of stay did not affect whether patients accepted testing. Acceptance of ED-based rapid HIV testing is not universal, and there are both patient and visit characteristics consistently associated with declining testing. This detracts from the goal of using the ED to screen a large number of at-risk patients who do not have access to testing elsewhere. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Dimensions and Characteristics of Personnel Manager Perceptions of Effective Drug-Testing Programs.

    ERIC Educational Resources Information Center

    Gomez-Mejia, Luis R.; Balkin, David B.

    1987-01-01

    Examined characteristics of drug-testing programs that were associated with personnel managers' judgments of the programs' effectiveness using data gathered from human resource managers (N=190). Results showed drug-testing programs considered to be effective were supported by ancillary activities (such as employee assistance programs), targeted…

  15. 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.

  16. 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…

  17. 30 CFR 250.407 - What tests must I conduct to determine reservoir characteristics?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 2 2013-07-01 2013-07-01 false What tests must I conduct to determine... 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, or...

  18. 30 CFR 250.407 - What tests must I conduct to determine reservoir characteristics?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false What tests must I conduct to determine... 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, or...

  19. 30 CFR 250.407 - What tests must I conduct to determine reservoir characteristics?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false What tests must I conduct to determine... 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, or...

  20. 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

  1. Impact of experimental hypercalcemia on routine haemostasis testing.

    PubMed

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

    2017-01-01

    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. 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. 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. 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.

  2. 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

  3. 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.

  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. Patient and family impact of pediatric genitourinary diagnostic imaging tests.

    PubMed

    Nelson, Caleb P; Chow, Jeanne S; Rosoklija, Ilina; Ziniel, Sonja; Routh, Jonathan C; Cilento, Bartley G

    2012-10-01

    The impact of diagnostic genitourinary imaging on patients and families is poorly understood. We measured patient and family reaction to commonly performed genitourinary imaging studies using a standardized measurement tool. We surveyed families undergoing genitourinary imaging (renal ultrasound, voiding cystourethrography, radionuclide cystogram, static renal scintigraphy and diuretic renal scintigraphy) using a Likert scaled 11-item survey to assess impact across 4 domains (pain, anxiety, time, satisfaction). Survey scores were analyzed using ANOVA and linear regression. A total of 263 families were surveyed (61 renal ultrasound, 52 voiding cystourethrogram, 55 radionuclide cystogram, 47 mercaptoacetyltriglycine dynamic renal scintigraphy, 48 dimercaptosuccinic acid static renal scintigraphy). Mean patient age was 2.1 years old. Of the patients 45% were male and 77% were white. Patient age, gender and prior genitourinary imaging experience varied by study type. Study type was significantly associated with total and weighted scores on the genitourinary imaging survey (both p <0.0001). Renal ultrasound was scored as better and mercaptoacetyltriglycine dynamic renal scintigraphy was worse than voiding cystourethrogram, radionuclide cystogram and dimercaptosuccinic acid static renal scintigraphy, which did not differ from each other. Other factors associated with worse total scores included patient age 1 to 3 years (p <0.001) and nonwhite race (p = 0.04). Gender, prior testing history, wait time and parent education were not associated with total scores. In the multivariate model renal ultrasound remained the best and mercaptoacetyltriglycine dynamic renal scintigraphy the worst (p <0.0001). In a direct comparison dimercaptosuccinic acid static renal scintigraphy and voiding cystourethrogram total scores did not differ (p = 0.59). There were significant differences among genitourinary imaging studies regarding the patient/family experience, but there was no overall

  6. 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). ...

  7. 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). ...

  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, 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). ...

  10. 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). ...

  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. Impact of Climate Change on Extreme Rainfall in France Throughout Trend Detections in Average Climatic Characteristics

    NASA Astrophysics Data System (ADS)

    Cantet, P.; Arnaud, P.

    2008-12-01

    The great interest on climate change during these last years has led to a quasi unanimous conclusion for scientists: the Earth climate changes. An increase of precipitation in the middle and high latitude area of north hemisphere was detected. In order to prevent hydrological risks, it's interesting to know if these global changes lead to an increase of extreme events. Indeed in the hydrologic context, the estimation of return period is primary for hydraulic building dimensioning. When considering problem of fire, urbanisation, hydrological installations, the study of water runoff alone can be misleading. So we must do a preliminary work on rainfall. However climate models have difficulties to represent efficiently extreme events. Moreover classical statistical methods seem to be limited because of the lack of very long series which can lead to a bad estimation of distribution tails. An original approach is applied to estimate impacts of climate change on extreme events in using an hourly rainfall stochastic generator which can be coupled with a rainfall-runoff model. The climate evolution is detected by the generator parameters. These parameters are estimated by an average, and not by extreme values, of climatic characteristics. From daily information of 139 rain gauge stations, evolution of generator parameters has been studied in the metropolitan France between 1960 and 2003. We applied the Poisson-Pareto-Peak-Over-Threshold model and linear trend has been tested by the Maximum Likelihood Ratio test. Parameter evolution has been evaluated from a regional approach in clustering several stations. Changes on average rainfall characteristics are amplified on extremes. The observed trends occur mainly between December and May. Taking into account the climate change doesn't lead to a big change in the quantiles estimation compared to their estimation under a hypothesis of climate stationary. But if observed trends are confirmed in the future, extreme event occurrence

  13. 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.

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

    PubMed

    Kim, Kyong-Jee; Hwang, Jee-Young

    2016-03-01

    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. 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. 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. 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.

  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. 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.

  17. 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

  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. 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.

  20. Determination of operating characteristic, retesting, and testing amount probabilities associated with testing for the presence of Salmonella in foods.

    PubMed

    McClure, Foster D; Lee, Jung K

    2011-01-01

    The relatively small perceived probability associated with retesting a food for the presence of Salmonella at low levels is often considered as one of the reasons that a confirmatory or check-analysis tends to disagree in practice with the results of an original test. Given a retesting process where a retest is only performed to confirm an original positive Salmonella test, the probability that both the original and retest will test positive for Salmonella has been traditionally determined by some as the product of the probabilities of a positive Salmonella test for the original and retest samples. When examining the probabilities associated with the retesting process, we found that our results disagreed with those based on intuitions apparently held by others concerning how these probabilities should be calculated. For Salmonella testing, operating characteristic values were computed to demonstrate the protections afforded by the Salmonella sampling plans presented in the U.S. Food and Drug Administration's Bacteriological Analytical Manual and to obtain the probability of a positive Salmonella test. The geometric distribution was examined for possible utility in determining the probabilities associated with testing amounts, i.e., the number of Salmonella tests needed to obtain a positive test.

  1. Muscle activity in the leg is tuned in response to impact force characteristics.

    PubMed

    Boyer, Katherine A; Nigg, Benno M

    2004-10-01

    Based on results from quasi-static experiments, it has been suggested that the lower extremity muscle activity is adjusted in reaction to impact forces with the goal of minimizing soft-tissue vibrations. It is not known whether a similar muscle tuning occurs during dynamic activities. Thus, the purpose of this study was to determine the effect of changes in the input signal on (a) vibrations of lower extremity soft-tissue packages and (b) EMG activity of related muscles during heel-toe running. Subjects performed heel-toe running in five different shoe conditions. Ground reaction forces were measured with a KISTLER force platform, soft-tissue vibrations were measured with tri-axial accelerometers and muscle activity was measured using surface EMG from the quadriceps, hamstrings, tibialis anterior and triceps surae groups from 10 subjects. By changing both the speed of running and the shoe midsole material the impact force characteristics were changed. There was no effect of changes in the input signal on the soft-tissue peak acceleration following impact. A significant correlation (R2=0.819) between the EMG pre-activation intensity and the impact loading rate changes was found for the quadriceps. In addition, the input frequency was shown to approach the vibration frequency of the quadriceps. This evidence supports the proposed paradigm that muscle activity is tuned to impact force characteristics to control the soft-tissue vibrations.

  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. 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.

  4. Test characteristics from latent-class models of the California Mastitis Test.

    PubMed

    Sanford, C J; Keefe, G P; Sanchez, J; Dingwell, R T; Barkema, H W; Leslie, K E; Dohoo, I R

    2006-11-17

    We evaluated (using latent-class models) the ability of the California Mastitis Test (CMT) to identify cows with intramammary infections on the day of dry-off. The positive and negative predictive values of this test to identify cows requiring dry-cow antibiotics (i.e. infected) was also assessed. We used 752 Holstein-Friesian cows from 11 herds for this investigation. Milk samples were collected for bacteriology, and the CMT was performed cow-side, prior to milking on the day of dry-off. At the cow-level, the sensitivity and specificity of the CMT (using the four quarter results interpreted in parallel) for identifying all pathogens were estimated at 70 and 48%, respectively. If only major pathogens were considered the sensitivity of the CMT increased to 86%. The negative predictive value of the CMT was >95% for herds with major-pathogen intramammary-infection prevalence <15%, so that selective dry-cow therapy might be reasonable for such herds if cows were screened with the CMT.

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

    NASA Astrophysics Data System (ADS)

    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.

  6. 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.

  7. Research of factors influencing centrifugal pump external characteristics based on orthogonal test

    NASA Astrophysics Data System (ADS)

    Huang, X. B.; Liu, Z. Q.

    2013-12-01

    In order to investigate the impact on external characteristics of single-stage and single-suction centrifugal pump, four parameters: cutwater gap(δ), blade number(z), impeller outlet width(b) and blade outlet angle(β) were taken into account. Orthogonal test method is a method which can make a comprehensive comparison among factors we are interested in. Thereby, it can't be more appropriate to adopt this approach to study the influence of the four factors referred above. Based on the prototype pump's geometric parameters, each of these factors took four levels. According to the principle of selecting orthogonal array, the L16(45) array was selected and 16 models were designed. After that, commercial CFD software CFX was used to calculate the head and efficiency under different conditions to determine the optimal operating condition Qr. The 16 models' rated flow rates were basically smaller than the prototype's. Considering this difference, in order to analyze the influence on the head under similar condition, the flow rate was made dimensionless and 3 conditions are chosen(Qr/Q=1, 1.25 and 1.375). Through the analysis of averaged respond head and efficiency, the laws of head and efficiency changing with the variation of the factors were obtained. Commonly, if a dependent's change cause by a independent variable is smaller than 5%, we can neglect the independent variable's effect. Thus the paper presents a research showing the factors' changing limitations considering the head changing by a percentage smaller than 5%. The conclusion of this article has important reference value for design of centrifugal pumps.

  8. 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

  9. 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)

  10. 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

  11. 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

  12. 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…

  13. Landing-Impact Characteristics of Load-Alleviating Struts on a Model of a Winged Space Vehicle

    NASA Technical Reports Server (NTRS)

    Blanchard, Ulysse J.

    1960-01-01

    A brief experimental investigation was made of the landing-impact characteristics of a 1/9-scale dynamic model of a winged space vehicle. The landing tests were made by catapulting a free model onto a hard; surface runway and onto water. The model had a conical fuselage and a flat - plate wing with a basic delta planform and 75 deg sweepback of the leading edge. The use of yielding-metal shock absorbers and various landing-gear arrangements was investigated during landing impact. The basic landing gear consisted of a dual rubber-tired nose wheel and twin main skids aft of the center of gravity near the wing tips. landing motion and acceleration data were obtained over a range of landing attitudes, gross weights, and initial sinking speeds. Brief tests were made with an alternate nose-wheel location. An all-skid configuration also was briefly evaluated for hard-surface and water landings. The landing gear employing yielding struts for impact-energy absorption during hard-surface landings resulted in accelerations of approximately 5 1/2 g near the nose gear over a range of landing parameters. Replacing the nose wheel and tire with a skid did not significantly change the accelerations. Landings in smooth water with rigid struts and adequate planing area at the nose skid resulted in a maximum landing acceleration of approximately 4g.

  14. [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.

  15. 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.

  16. 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.

  17. 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.

  18. Drop impact characteristics and structure effects of hydrophobic surfaces with micro- and/or nanoscaled structures.

    PubMed

    Kim, Hyungmo; Lee, Chan; Kim, Moo Hwan; Kim, Joonwon

    2012-07-31

    We report the drop impact characteristics on four hydrophobic surfaces with different well-scale structures (smooth, nano, micro, and hierarchical micro/nano) and the effects of those structures on the behavior of water drops during impact. The specimens were fabricated using silicon wet etching, black silicon formation, or the combination of these methods. On the surfaces, the microstructures form obstacles to drop spreading and retracting, the nanostructures give extreme water-repellency, and the hierarchical micro/nanostructures facilitate drop fragmentation. The maximum spreading factor (D*(max)) differed among the structures. On the basis of published models of D*(max), we interpret the results of our experiment and suggest reasonable explanations for these differences. Especially, the micro/nanostructures caused instability of the interface between liquid and air at Weber number We > ~80 and impacting drops fragmented at We > ~150.

  19. 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.

  20. [Citation characteristics of German authors in "Der Chirurg": hegemony of the impact factor].

    PubMed

    Hasse, W; Fischer, R J

    2010-04-01

    Characteristics of citation and language in publications of German authors from the journal "Der Chirurg" (vol 78, 2007) were analysed. Out of a total of 3,342 citations, 756 (22.62%) were from German authors with 248 (32.8) self-citations. The hegemony of the impact factor in science, research and education is critically discussed. The imbalance between the number of surgeons in the US and United Kingdom (66,032) and surgeons in the German speaking countries in Europe (25,300) is compared with respect to the counting methods used to create the impact factor of a journal. The creation of an independent impact factor in Europe and the development of an EU-based citation data bank which allows unselected access to national language scientific literature are strongly needed.

  1. The impact of airport characteristics on airport surface accidents and incidents.

    PubMed

    Wilke, Sabine; Majumdar, Arnab; Ochieng, Washington Y

    2015-06-01

    Airport surface safety and in particular runway and taxiway safety is acknowledged globally as one of aviation's greatest challenges. To improve this key area of aviation safety, it is necessary to identify and understand the causal and contributing factors on safety occurrences. While the contribution of human factors, operations, and procedures has been researched extensively, the impact of the airport and its associated characteristics itself has received little or no attention. This paper introduces a novel methodology for risk and hazard assessment of airport surface operations, and models the relationships between airport characteristics, and (a) the rate of occurrences, (b) the severity of occurrences, and (c) the causal factors underlying occurrences. The results show for the first time how the characteristics of airports, and in particular its infrastructure and operations, influence the safety of surface operations. Copyright © 2015 Elsevier Ltd. and National Safety Council. Published by Elsevier Ltd. All rights reserved.

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

    NASA Technical Reports Server (NTRS)

    Nettles, A. T.

    1990-01-01

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

  3. 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.

  4. Selected Socioeconomic Characteristics of Farmers Associated with the Use of Soil Testing.

    ERIC Educational Resources Information Center

    Ott, Harold R.

    A study was conducted to determine whether a relationship exists between several selected socioeconomic characteristics and the adoption or non-adoption of soil testing as a farm management tool and to establish whether or not a statistically significant relationship exists between adopters and imperfect adopters (discontinuers). Data were…

  5. Linking Student and Programmatic Characteristics to Test Performance: Issues and Solutions.

    ERIC Educational Resources Information Center

    Liu, Kristin Kline; Thurlow, Martha; Albus, Debra; Spicuzza, Richard; Minnema, Jane

    This study was conducted to analyze student background characteristics and educational history data that affect participation and performance of non-English language background students, including those with limited English proficiency, on Minnesota's Basic Standards Test. Data were obtained from individual student cumulative files in six schools…

  6. 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…

  7. 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…

  8. 30 CFR 250.407 - What tests must I conduct to determine reservoir characteristics?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., 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 I... reservoir characteristics of oil, gas, sulphur, and water in the formations penetrated by logging, formation...

  9. 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…

  10. Electrofracturing test system and method of determining material characteristics of electrofractured material samples

    DOEpatents

    Bauer, Stephen J.; Glover, Steven F.; Pfeifle, Tom; Su, Jiann-Cherng; Williamson, Kenneth Martin; Broome, Scott Thomas; Gardner, William Payton

    2017-08-01

    A device for electrofracturing a material sample and analyzing the material sample is disclosed. The device simulates an in situ electrofracturing environment so as to obtain electrofractured material characteristics representative of field applications while allowing permeability testing of the fractured sample under in situ conditions.

  11. 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…

  12. 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…

  13. Impact properties of 304L stainless steel GTAW joints evaluated by high strain rate of compression tests

    NASA Astrophysics Data System (ADS)

    Lee, Woei-Shyan; Lin, Chi-Feng; Liu, Chen-Yang; Tzeng, Fan-Tzung

    2004-12-01

    This paper presents an investigation into the high velocity impact of 304L stainless steel gas tungsten arc welded (GTAW) joints at strain rates between 10-3 and 7.5 × 103 s-1 using a compressive split-Hopkinson bar. The results show that the impact properties and fracture characteristics of the tested weldments depend strongly on applied strain rate. This rate-dependent behavior is in good agreement with model predictions using the hybrid Zerilli-Armstrong constitutive law. It is determined that the tested weldments fail as a result of adiabatic shearing. The fracture surfaces of the fusion zone and base metal regions are characterized by the presence of elongated dimples. The variation in the observed dimple features with strain rate is consistent with the results of the impact stress-strain curves.

  14. 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.

  15. 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…

  16. Acoustical characteristics of the NASA Langley full scale wind tunnel test section

    NASA Technical Reports Server (NTRS)

    Abrahamson, A. L.; Kasper, P. K.; Pappa, R. S.

    1975-01-01

    The full-scale wind tunnel at NASA-Langley Research Center was designed for low-speed aerodynamic testing of aircraft. Sound absorbing treatment has been added to the ceiling and walls of the tunnel test section to create a more anechoic condition for taking acoustical measurements during aerodynamic tests. The results of an experimental investigation of the present acoustical characteristics of the tunnel test section are presented. The experimental program included measurements of ambient nosie levels existing during various tunnel operating conditions, investigation of the sound field produced by an omnidirectional source, and determination of sound field decay rates for impulsive noise excitation. A comparison of the current results with previous measurements shows that the added sound treatment has improved the acoustical condition of the tunnel test section. An analysis of the data indicate that sound reflections from the tunnel ground-board platform could create difficulties in the interpretation of actual test results.

  17. 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.

  18. 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.

  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. 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

  5. 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.

  6. 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'.

  7. SGC Tests for Influence of Material Composition on Compaction Characteristic of Asphalt Mixtures

    PubMed Central

    Chen, Qun

    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. PMID:23818830

  8. 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.

  9. 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.

  10. 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.

  11. Cognitive Dysfunction after On-Pump Operations: Neuropsychological Characteristics and Optimal Core Battery of Tests

    PubMed Central

    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. PMID:24955279

  12. 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.

  13. 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.

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

    PubMed

    Qureshi, S A; Shabnam, J

    2001-01-01

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

  15. The impact of material characteristics on tire pavement interaction noise for flexible pavements

    NASA Astrophysics Data System (ADS)

    Kocak, Salih

    Noise pollution has recently been one of the growing problems all over the world. While there are many sources of the noise, traffic noise is the main contributor to the total environmental noise. Although there are different sources for traffic noise, the tire pavement interaction noise is the most dominant component within most city and highway limits. One of the ways to reduce the tire pavement noise is to improve the material characteristics of the pavements such that they produce less noise. In this study, the relationship between basic material characteristics (e.g., Hot Mix Asphalt (HMA) volumetrics) and sound generation and absorption characteristics of flexible pavements was investigated. In addition, the effect of linear visco-elastic properties (e.g., dynamic modulus (|E*|) and phase angle (delta)) on sound absorption was studied. In order to focus only on impact of material characteristics and overshadow the effect of surface texture, a novel laboratory tire pavement noise measurement simulator (TIPANOS) was developed. The statistical analysis results showed that although the individual material characteristics do not have appreciable influence on sound absorption, there is a significant correlation between sound pressure levels (SPL) and combination of several material and linear visco-elastic parameters.

  16. 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. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Baseline characteristics and statistical implications for the OECD 210 fish early-life stage chronic toxicity test.

    PubMed

    Oris, James T; Belanger, Scott E; Bailer, A John

    2012-02-01

    The fish toxicity assay most commonly used to establish chronic effects is the Organisation for Economic Co-operation and Development (OECD) 210, fish early-life stage test. However, the authors are not aware of any systematic analysis of the experimental design or statistical characteristics of the test since the test guideline was adopted nearly 20 years ago. Here, the authors report the results of an analysis of data compiled from OECD 210 tests conducted by industry labs. The distribution of responses observed in control treatments was analyzed, with the goal of understanding the implication of this variability on the sensitivity of the OECD 210 test guideline and providing recommendations on revised experimental design requirements of the test. Studies were confined to fathead minnows, rainbow trout, and zebrafish. Dichotomous endpoints (hatching success and posthatch survival) were examined for indications of overdispersion to evaluate whether significant chamber-to-chamber variability was present. Dichotomous and continuous (length, wet wt, dry wt) measurement endpoints were analyzed to determine minimum sample size requirements to detect differences from control responses with specified power. Results of the analysis indicated that sensitivity of the test could be improved by maximizing the number of replicate chambers per treatment concentration, increasing the acceptable level of control hatching success and larval survival compared to current levels, using wet weight measurements rather than dry weight, and focusing test efforts on species that demonstrate less variability in outcome measures. From these analyses, the authors provide evidence of the impact of expected levels of variability on the sensitivity of traditional OECD 210 studies and the implications for defining a target for future animal alternative methods for chronic toxicity testing in fish. Copyright © 2011 SETAC.

  18. 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

  19. 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.

  20. The impact of different footwear characteristics, of a ballet flat pump, on centre of pressure progression and perceived comfort.

    PubMed

    Branthwaite, Helen; Chockalingam, Nachiappan; Greenhalgh, Andrew; Chatzistergos, Panagiotis

    2014-09-01

    Uncomfortable shoes have been attributed to poor fit and the cause of foot pathologies. Assessing and evaluating comfort and fit have proven challenging due to the subjective nature. The aim of this paper is to investigate the relationship between footwear characteristics and perceived comfort. Twenty-seven females assessed three different styles of ballet pump shoe for comfort using a comfort scale whilst walking along a 20 m walkway. The physical characteristics of the shoes and the progression of centre of pressure during walking were assessed. There were significant physical differences between each style, square shoe being the shortest, widest and stiffest and round shoe having the least volume at the toe box. Centre of pressure progression angle was centralised to the longitudinal axis of the foot when wearing each of the three shoes compared to barefoot. Length, width and cantilever bending stiffness had no impact on perceived comfort. Wearing snug fitting flexible soled round ballet flat pump is perceived to be the most comfortable of the shoe shapes tested producing a faster more efficient gait. Further investigations are required to assess impact/fit and upper material on perceived comfort to aid consumers with painful feet in purchasing shoes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Benchmark tests on symmetry and continuity characteristics between BSIM4 and ULTRA-BULK

    NASA Astrophysics Data System (ADS)

    Xudong, Niu; Bo, Li; Yan, Song; Lining, Zhang; Jin, He

    2009-03-01

    This paper presents the benchmark test results on the symmetry and continuity characteristics between BSIM4 from Berkeley and ULTRA-BULK from Peking University. It is shown that the industry standard model BSIM4 has a series of the shortcomings of the continuity and symmetry, such as the charge, high-order current derivatives, and the trans-capacitances while the latest advanced surface-potential based MOSFET compact model, ULTRA-BULK, demonstrates all necessary continuity and symmetry characteristics, which are very important for analog and RF circuit design.

  2. 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.

  3. 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

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

    MedlinePlus

    ... the small minority of women for whom the test may be helpful. The psychological, emotional and social implications of genetic testing also are worth considering, both for yourself and for members of your ... test results, including: Anxiety about developing cancer. Having an ...

  5. 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.

  6. 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.

  7. 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

  8. 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.

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

    PubMed

    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

    2016-12-06

    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.

  10. The Impact of Prematriculation Admission Characteristics on Graduation Rates in an Accelerated Doctor of Pharmacy Program.

    PubMed

    Steinberg, Michael; Morin, Anna K

    2015-10-25

    Objective. To evaluate the impact of admission characteristics on graduation in an accelerated doctor of pharmacy (PharmD) program. Methods. Selected prematriculation characteristics of students entering the graduation class years of 2009-2012 on the Worcester and Manchester campuses of MCPHS University were analyzed and compared for on-time graduation. Results. Eighty-two percent of evaluated students (699 of 852) graduated on time. Students who were most likely to graduate on-time attended a 4-year school, previously earned a bachelor's degree, had an overall prematriculation grade point average (GPA) greater than or equal to 3.6, and graduated in the spring just prior to matriculating to the university. Factors that reduced the likelihood of graduating on time were also identified. Work experience had a marginal impact on graduating on time. Conclusion. Although there is no certainty in college admission decisions, prematriculation characteristics can help predict the likelihood for academic success of students in an accelerated PharmD program.

  11. 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.

  12. 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.

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

    PubMed Central

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

    1994-01-01

    The purpose of this study was to evaluate the impact of anonymous testing availability on human immunodeficiency virus (HIV) test demand in Arizona. Testing patterns before and after the introduction of anonymous testing were compared. Client knowledge of new test policy and delay in testing until an anonymous option was available were assessed. Test numbers among men who have sex with men showed a statistically significant increase after introduction of an anonymous testing option. Arizona continues to maintain anonymous testing availability. Public health agencies should consider how test policy may influence people's HIV test decisions. PMID:7998649

  16. 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.

  17. 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.

  18. Methacholine challenge test: diagnostic characteristics in asthmatic patients receiving controller medications.

    PubMed

    Sumino, Kaharu; Sugar, Elizabeth A; Irvin, Charles G; Kaminsky, David A; Shade, Dave; Wei, Christine Y; Holbrook, Janet T; Wise, Robert A; Castro, Mario

    2012-07-01

    The methacholine challenge test (MCT) is commonly used to assess airway hyperresponsiveness, but the diagnostic characteristics have not been well studied in asthmatic patients receiving controller medications after the use of high-potency inhaled corticosteroids became common. We investigated the ability of the MCT to differentiate participants with a physician's diagnosis of asthma from nonasthmatic participants. We conducted a cohort-control study in asthmatic participants (n= 126) who were receiving regular controller medications and nonasthmatic control participants (n= 93) to evaluate the sensitivity and specificity of the MCT. The overall sensitivity was 77% and the specificity was 96% with a threshold PC(20) (the provocative concentration of methacholine that results in a 20% drop in FEV(1)) of 8 mg/mL. The sensitivity was significantly lower in white than in African American participants (69% vs 95%, P= .015) and higher in atopic compared with nonatopic (82% vs 52%, P= .005). Increasing the PC(20) threshold from 8 to 16 mg/mL did not noticeably improve the performance characteristics of the test. African American race, presence of atopy, and lower percent predicted FEV(1) were associated with a positive test result. The utility of the MCT to rule out a diagnosis of asthma depends on racial and atopic characteristics. Clinicians should take into account the reduced sensitivity of the MCT in white and nonatopic asthmatic patients when using this test for the diagnosis of asthma. Copyright © 2012 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

  19. Test Characteristics of Fecal Immunochemical Tests (FIT) Compared with Optical Colonoscopy Revised JMS-14-003.R2

    PubMed Central

    Levy, Barcey T.; Bay, Camden; Xu, Yinghui; Daly, Jeanette M.; Bergus, George; Dunkelberg, Jeffrey; Moss, Carol

    2014-01-01

    Background Faecal occult blood tests are often the initial test in population-based screening. We aimed to: 1) compare the results of single sample faecal immunochemical tests (FITs) with colonoscopy, and 2) calculate the sensitivity for proximal vs. distal adenomatous polyps or cancer. Methods Individuals scheduled for a colonoscopy were invited to complete a FIT prior to their colonoscopy preparation. FIT results were classified as positive, negative, or invalid. Colonoscopy reports were reviewed and abstracted. Because of product issues, four different FIT manufacturers were used. The test characteristics for each FIT manufacturer were calculated for advanced adenomatous polyps or cancer according to broad reason for colonoscopy (screening or surveillance/diagnostic). Results Of those invited, 1,026 individuals (43.9%) completed their colonoscopy and had a valid FIT result. The overall sensitivity of the FITs (95% confidence intervals) was 0.18 (0.10 to 0.28) and specificity was 0.90 (0.87 to 0.91) for advanced adenomas or cancer. The sensitivity for distal lesions was 0.23 (0.11 to 0.38) and for proximal lesions was 0.09 (0.02 to 0.25). The odds ratio of an individual with a distal advanced adenoma or cancer testing positive was 2.68 (1.20 to 5.99). The two individuals with colorectal cancer tested negative, as did one individual with high-grade dysplasia. Conclusions The sensitivity of a single-sample FIT for advanced adenomas or cancer was low. Individuals with distal adenomas had a higher odds of testing positive than those with proximal lesions or no lesions. PMID:24958730

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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…

  5. 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.

  6. 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.

  7. 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...

  8. Estimating Future Adverse Impact Using Selection Ratios and Group Differences in Test Score Means.

    ERIC Educational Resources Information Center

    Aamodt, Michael G.; And Others

    Estimating the validity of a test is only one concern for the human resources professional developing a personnel selection battery. An equally important concern is whether the test will result in adverse impact against a member of a protected class. It would be useful if the probability of adverse impact could be estimated prior to spending time…

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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…

  14. Impact of parasitic resistances on the electrical characteristics of a SiC MESFET

    NASA Astrophysics Data System (ADS)

    Dutta, Sutanu

    2017-10-01

    The mathematical formulations of extrinsic resistances of a SiC-MESFET are developed and their impact on the electrical characteristics of the device has been studied in this work. Numerical techniques are used to calculate the drain current of a MESFET considering the existence of parasitic resistances. The analytical expressions of drain conductance, mutual conductance and cut off frequency of the device have been derived and their variations over different device parameters are studied incorporating the effect of extrinsic resistances. It is observed that the impact of parasitic resistances on the drain current and other parameters of the device is significant and device performance usually degrades with parasitic resistances. The parasitic resistances computed using our approach is compared with the experimentally extracted data reported earlier and a reasonably good agreement has been observed.

  15. 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.

  16. Metformin: A Review of characteristics, properties, analytical methods and impact in the green chemistry.

    PubMed

    Trindade, Mariana Teixeira da; Kogawa, Ana Carolina; Salgado, Hérida Regina Nunes

    2017-09-11

    Diabetes mellitus is considered a public health problem. The initial treatment consists of improving the lifestyle and making changes in the diet. When these changes are not enough, the use of medication becomes necessary. The metformin aims to reduce the hepatic production of glucose and is the preferred treatment for type 2. The objective is to survey the characteristics and properties of metformin, as well as hold a discussion on the existing analytical methods to green chemistry and their impacts for both the operator and the environment. For the survey data searches were conducted by scientific papers in the literature as well as in official compendium. The characteristics and properties are shown, also, methods using liquid chromatography techniques, titration, absorption spectrophotometry in the ultraviolet and the infrared region. Most of the methods presented are not green chemistry oriented. It is necessary the awareness of everyone involved in the optimization of the methods applied through the implementation of green chemistry to determine the metformin.

  17. Impedance characteristics of DFIGs considering the impacts of DFIG numbers and its application on SSR analysis

    NASA Astrophysics Data System (ADS)

    You, J. J.; Ning, W. Y.; Jiang, H.; Dong, Y. X.; Liu, H.; Li, Y.

    2017-05-01

    Sub-synchronous resonance (SSR) occurred in the power system with both Doubly Fed Induction Generators (DFIGs) and series-compensated lines. There have been several papers focusing on the analysis of such SSR phenomenon. To the authors’ knowledge, the impacts of DFIG numbers are seldom considered in existing papers. In this paper, the impedance characteristics of DFIGs under different numbers are analyzed. Then the relationship between DFIG numbers and SSR characteristics is discussed. The contributions to be included in the paper are as following: 1) the impedance of N DFIGs is roughly equal to 1/N of the impedance of one DFIG. 2) The SSR risk of system is related with both the numbers of DFIGs and the parameters of the series-compensated lines.

  18. Analysis of casing treatment’s impact on the axial compressor model stage characteristics

    NASA Astrophysics Data System (ADS)

    Tribunskaia, K.; Kozhukhov, Y. V.

    2017-08-01

    There are special requirements for the compressors of aircraft engines. They must ensure maximum efficiency in a maximally large stable work zone Due to a high pressure ratio these stages are more susceptible to the losses from radial clearance. One of the approaches to reduce such losses is the application of above-rotor devices. In the following study there is considered the impact of such treatments on the compressor stage performance. Despite the fact that there is a sufficient amount of research about this issue, their results are contradictory. The use of these devices can affect the characteristics of compressor stage performance both positively and negatively. This study was conducted using the methods of computational fluid dynamics and was based on the NASA Rotor-37 geometry model stage. Results were obtained through the comparison of the characteristics of stages with and without above-rotor devices.

  19. Reliability of the Functional Reach Test and the influence of anthropometric characteristics on test results in subjects with hemiparesis.

    PubMed

    Martins, Emerson Fachin; de Menezes, Lidiane Teles; de Sousa, Pedro Henrique Côrtes; de Araujo Barbosa, Paulo Henrique Ferreira; Costa, Abraão Souza

    2012-01-01

    First designed as an alternative method of assessing balance and susceptibility to falls among elderly, the Functional Reach Test (FR) has also been used among patients with hemiparesis. Then this study aimed to describe the intra- and inter-rater and the test/re-test reliability of the FR measure in subjects with and without hemiparesis while verifying anthropometric influences on the measurements. The FR was administered to a sample of subjects with hemiparesis and to a control group that was matched by gender and age. A two-way analysis of variance was used to verify the intra-rater reliability. It was calculated using the differences between the averages of the measures obtained during single, double or triple trials. The intra-class correlation coefficient (ICC) was utilized and data plotted using the Bland-Altman method. Associations were analyzed using Pearson's correlation coefficient. In general, the intra-rater analysis did not show significant differences between the measures for the single, double or triple trials. Excellent ICC values were observed, and there were no significant associations with anthropometric parameters for the hemiparesis and control subjects. FR showed good reliability for patients with and without hemiparesis and the test measurements were not significantly associated with the anthropometric characteristics of the subjects.

  20. 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.