Science.gov

Sample records for aged material evaluations

  1. In-service irradiated and aged material evaluations

    SciTech Connect

    Haggag, F.M.; Nanstad, R.K.; Alexander, D.J.

    1995-10-01

    The objective of this task is to provide a direct assessment of actual material properties in irradiated components of nuclear reactors, including the effects of irradiation and aging. Four activities are currently in progress: (1) establishing a machining capability for contaminated or activated materials by completing procurement and installation of a computer-based milling machine in a hot cell; (2) machining and testing specimens from cladding materials removed from the Gundremmingen reactor to establish their fracture properties; (3) preparing an interpretive report on the effects of neutron irradiation on cladding; and (4) continuing the evaluation of long-term aging of austenitic structural stainless steel weld metal by metallurgically examining and testing specimens aged at 288 and 343{degrees}C and reporting the results, as well as by continuing the aging of the stainless steel cladding toward a total time of 50,000 h.

  2. Evaluation of Ultrasonic and Thermal Nondestructive Evaluation for the Characterization of Aging Degradation in Braided Composite Materials

    NASA Technical Reports Server (NTRS)

    Martin, Richard E.

    2010-01-01

    This paper examines the ability of traditional nondestructive evaluation (NDE) techniques to measure the degradation of braided polymer composite materials subjected to thermal-humidity cycling to simulate aging. A series of braided composite coupons were examined using immersion ultrasonic and pulsed thermography techniques in the as received condition. These same specimens were then examined following extended thermal-humidity cycling. Results of this examination did not show a significant change in the resulting (NDE) signals.

  3. Fireset materials aging study

    SciTech Connect

    Smith, H.M.; Arnold, C.; Bailey, M.E.

    1982-07-01

    A thermally-accelerated aging study of 10 selected organic materials used in a fireset has been conducted. The study included both quantitative and qualitative gas analyses as well as the measurement of physical properties before and after accelerated aging. The test plan involved single material aging, as well as pairs and larger groups to look for synergistic interactions. The material types tested were epoxies, polyurethanes, polysulfides, silicones, phenolics, polyolefins, and diallyl phthalates. Only two of the materials tested showed evidence of degradation as a result of aging.

  4. Quantitative evaluation of material degradation of thermally aged duplex stainless steels using chemical immersion test

    NASA Astrophysics Data System (ADS)

    Yi, Y. S.; Shoji, T.

    1996-12-01

    In order to develop a non-destructive evaluation technique for detection of thermal aging embrittlement of duplex stainless steels, corrosion tests on unaged and aged specimens of cast duplex stainless steels were performed in 5 wt% HCl solution. After the immersion test, the dissolution rate of specimens was obtained by a dissolved depth measurement with an AFM. In the measurements of dissolved depths, a replica technique was used for easier handling and also for a possible field application of the AFM analysis method. Changes in corrosion properties by aging measured in terms of the dissolved depth after the immersion were compared with the changes in mechanical properties by aging embrittlement. The changes in corrosion properties of unaged and aged specimen were analyzed in relation to the microstructural change by thermal aging. Based upon insights on the immersion test results and the comparison of the changes in corrosion properties and mechanical properties, a possible non-destructive detection and evaluation technique for thermal aging embrittlement by spinodal decomposition is proposed.

  5. Material property evaluations of bimetallic welds, stainless steel saw fusion lines, and materials affected by dynamic strain aging

    SciTech Connect

    Rudland, D.; Scott, P.; Marschall, C.; Wilkowski, G.

    1997-04-01

    Pipe fracture analyses can often reasonably predict the behavior of flawed piping. However, there are material applications with uncertainties in fracture behavior. This paper summarizes work on three such cases. First, the fracture behavior of bimetallic welds are discussed. The purpose of the study was to determine if current fracture analyses can predict the response of pipe with flaws in bimetallic welds. The weld joined sections of A516 Grade 70 carbon steel to F316 stainless steel. The crack was along the carbon steel base metal to Inconel 182 weld metal fusion line. Material properties from tensile and C(T) specimens were used to predict large pipe response. The major conclusion from the work is that fracture behavior of the weld could be evaluated with reasonable accuracy using properties of the carbon steel pipe and conventional J-estimation analyses. However, results may not be generally true for all bimetallic welds. Second, the toughness of austenitic steel submerged-arc weld (SAW) fusion lines is discussed. During large-scale pipe tests with flaws in the center of the SAW, the crack tended to grow into the fusion line. The fracture toughness of the base metal, the SAW, and the fusion line were determined and compared. The major conclusion reached is that although the fusion line had a higher initiation toughness than the weld metal, the fusion-line J-R curve reached a steady-state value while the SAW J-R curve increased. Last, carbon steel fracture experiments containing circumferential flaws with periods of unstable crack jumps during steady ductile tearing are discussed. These instabilities are believed to be due to dynamic strain aging (DSA). The paper discusses DSA, a screening criteria developed to predict DSA, and the ability of the current J-based methodologies to assess the effect of these crack instabilities. The effect of loading rate on the strength and toughness of several different carbon steel pipes at LWR temperatures is also discussed.

  6. Space aging of solid rocket materials

    NASA Technical Reports Server (NTRS)

    Lester, Dean M.; Jones, Leon L.; Smalley, R. B., Jr.; Ord, R. Neil

    1991-01-01

    Solid rocket propellant and rocket motor components were aged in a vented container on the interior of the LDEF. The results of aging IPSM-II/PAM-DII space motor components are presented. Ballistic and mechanical properties of the space aged main propellant, igniter propellant, and ignition system were compared with similar data from preflight and ground aged samples. Mechanical properties of the composite materials and bonded joints used in the motor case, insulation, liner, nozzle, exit cone, and skirt were similarly evaluated. The space aging results are compared to data collected in a ground based vacuum aging program on similar components.

  7. Experimental Techniques for Evaluating the Effects of Aging on Impact and High Strain Rate Properties of Triaxial Braided Composite Materials

    NASA Technical Reports Server (NTRS)

    Pereira, J. Michael; Roberts, Gary D.; Ruggeri, Charles R.; Gilat, Amos; Matrka, Thomas

    2010-01-01

    An experimental program is underway to measure the impact and high strain rate properties of triaxial braided composite materials and to quantify any degradation in properties as a result of thermal and hygroscopic aging typically encountered during service. Impact tests are being conducted on flat panels using a projectile designed to induce high rate deformation similar to that experienced in a jet engine fan case during a fan blade-out event. The tests are being conducted on as-fabricated panels and panels subjected to various numbers of aging cycles. High strain rate properties are being measured using a unique Hopkinson bar apparatus that has a larger diameter than conventional Hopkinson bars. This larger diameter is needed to measure representative material properties because of the large unit cell size of the materials examined in this work. In this paper the experimental techniques used for impact and high strain rate testing are described and some preliminary results are presented for both as-fabricated and aged composites.

  8. Space aging of solid rocket materials

    NASA Technical Reports Server (NTRS)

    Lester, Dean M.; Jones, Leon L.; Smalley, R. B., Jr.; Ord, R. Neil

    1992-01-01

    Solid rocket propellant and rocket motor components were aged in a vented container on the interior of the LDEF. This paper will present the results of aging the Improved Performance Space Motor-II/Payload Assist Module-Delta II (IPSM-II/PAM-DII) space motor components. Ballistic and mechanical properties of the space aged main propellant, igniter propellant, and ignition system were compared with similar data from preflight and ground aged samples. Mechanical properties of the composite materials and bonded joints used in the motor case, insulation, liner, nozzle, exit cone, and skirt were similarly evaluated. The space aging results will be compared to data collected in a ground based vacuum aging program on similar components. The operation of the vacuum actuated venting valve and pressure actuated resealing of the container will also be addressed. The materials tested showed no significant changes due to space aging. These results indicate that properly designed solid rocket motors can be expected to perform reliably after extended periods of exposure to a space environment.

  9. Accelerated Aging of Polymer Composite Bridge Materials

    SciTech Connect

    J. G. Rodriguez; L. G. Blackwood; L. L. Torres; N. M. Carlson; T. S. Yoder

    1999-03-01

    Accelerated aging research on samples of composite material and candidate ultraviolet (UV) protective coatings is determining the effects of six environmental factors on material durability. Candidate fastener materials are being evaluated to determine corrosion rates and crevice corrosion effects at load-bearing joints. This work supports field testing of a 30-ft long, 18-ft wide polymer matrix composite (PMC) bridge at the Idaho National Engineering and Environmental Laboratory (INEEL). Durability results and sensor data from tests with live loads provide information required for determining the cost/benefit measures to use in life-cycle planning, determining a maintenance strategy, establishing applicable inspection techniques, and establishing guidelines, standards, and acceptance criteria for PMC bridges for use in the transportation infrastructure.

  10. School Age Child Care Staff Training Evaluation.

    ERIC Educational Resources Information Center

    Gore, Jane S.; And Others

    A formative and summative evaluation was made of eight school-age child care (SACC) training workshops conducted in 1989-90 for 190 participants in upstate New York. (The focus of the SACC workshops was to "train the trainers," as well as to provide trainees with quality materials and instruction for future training with their staff members.) All…

  11. ALPHA SPECTROMETRIC EVALUATION OF SRM-995 AS A POTENTIAL URANIUM/THORIUM DOUBLE TRACER SYSTEM FOR AGE-DATING URANIUM MATERIALS

    SciTech Connect

    Beals, D.

    2011-12-06

    Uranium-233 (t{sub 1/2} {approx} 1.59E5 years) is an artificial, fissile isotope of uranium that has significant importance in nuclear forensics. The isotope provides a unique signature in determining the origin and provenance of uranium-bearing materials and is valuable as a mass spectrometric tracer. Alpha spectrometry was employed in the critical evaluation of a {sup 233}U standard reference material (SRM-995) as a dual tracer system based on the in-growth of {sup 229}Th (t{sub 1/2} {approx} 7.34E3 years) for {approx}35 years following radiochemical purification. Preliminary investigations focused on the isotopic analysis of standards and unmodified fractions of SRM-995; all samples were separated and purified using a multi-column anion-exchange scheme. The {sup 229}Th/{sup 233}U atom ratio for SRM-995 was found to be 1.598E-4 ({+-} 4.50%) using recovery-corrected radiochemical methods. Using the Bateman equations and relevant half-lives, this ratio reflects a material that was purified {approx} 36.8 years prior to this analysis. The calculated age is discussed in contrast with both the date of certification and the recorded date of last purification.

  12. Skylab parasol material evaluation

    NASA Technical Reports Server (NTRS)

    Jacobs, S.

    1975-01-01

    Results of experimental work to evaluate the degradation rate of a parasol that was used as a means of alleviating thermal problems encountered soon after the launch of the Skylab 1 space vehicle are presented. Material selection criteria are discussed; the material chosen is described, and results of tests performed after environmental exposure at five facilities are given. The facilities used for exposure to ultraviolet radiation/thermal-vacuum environments and the equipment used for testing physical properties before and after exposure are described. Comparisons of ground test and flight test data are included.

  13. Kevlar 49/Epoxy COPV Aging Evaluation

    NASA Technical Reports Server (NTRS)

    Sutter, James K.; Salem, Jonathan L.; Thesken, John C.; Russell, Richard W.; Littell, Justin; Ruggeri, Charles; Leifeste, Mark R.

    2008-01-01

    NASA initiated an effort to determine if the aging of Kevlar 49/Epoxy composite overwrapped pressure vessels (COPV) affected their performance. This study briefly reviews the history and certification of composite pressure vessels employed on NASA Orbiters. Tests to evaluate overwrap tensile strength changes compared 30 year old samples from Orbiter vessels to new Kevlar/Epoxy pressure vessel materials. Other tests include transverse compression and thermal analyses (glass transition and moduli). Results from these tests do not indicate a noticeable effect due to aging of the overwrap materials.

  14. [Research on the aging of all-ceramics restoration materials].

    PubMed

    Zhang, Dongjiao; Chen, Xinmin

    2011-10-01

    All-ceramic crowns and bridges have been widely used for dental restorations owing to their excellent functionality, aesthetics and biocompatibility. However, the premature clinical failure of all-ceramic crowns and bridges may easily occur when they are subjected to the complex environment of oral cavity. In the oral environment, all-ceramic materials are prone to aging. Aging can lead all-ceramic materials to change color, to lower bending strength, and to reduce anti-fracture toughness. There are many factors affecting the aging of the all-ceramic materials, for example, the grain size, the type of stabilizer, the residual stress and the water environment. In order to analyze the aging behavior, to optimize the design of all-ceramic crowns and bridges, and to evaluate the reliability and durability, we review in this paper recent research progress of aging behavior for all-ceramics restoration materials. PMID:22097281

  15. A preliminary mechanical property and stress corrosion evaluation of VIM-VAR work strengthened and direct aged Inconel 718 bar material

    NASA Technical Reports Server (NTRS)

    Montano, J. W.

    1987-01-01

    This report presents a preliminary mechanical property and stress corrosion evaluation of double melted (vacuum induction melted (VIM), and vacuum arc remelted (VAR)), solution treated, work strengthened and direct aged Inconel 718 alloy bar (5.50 in. (13.97 cm) diameter). Two sets of tensile specimens, one direct single aged and the other direct double aged, were tested at ambient temperature in both the longitudinal and transverse directions. Longitudinal tensile and yield strengths in excess of 200 ksi (1378.96 MPa) and 168 ksi (1158.33 MPa), respectively, were realized at ambient temperature, for the direct double aged specimen. No failures occurred in the single or double edged longitudinal and transverse tensile specimens stressed to 75 and 100 percent of their respective yield strengths and exposed to a salt fog environment for 180 days. Tensile tests performed after the stress corrosion test showed no mechanical property degradation.

  16. The Material Convoy After Age 50

    PubMed Central

    2014-01-01

    Objectives. Possessions constitute a dynamic “material convoy” that accumulates across adulthood to furnish role enactments and the development of the self. Following a familiar life course arc, older people should hypothetically release the possessions that equipped the daily lives that they no longer have. Method. We use new survey data on possession divestment from the 2010 Health and Retirement Study to assess activity on behalf of the material convoy after age 50. Results. After age 50, people are progressively less likely to divest themselves of belongings. After age 70, about 30% of persons say that they have done nothing in the past year to clean out, give away, or donate things, and over 80% have sold nothing. We tested whether divestments diminish with age because they do not seem necessary or because of health limitations, but the age pattern is robust, suggesting retention of the material convoy in later life. Discussion. Further research on this age pattern might consider housing, the construction of the self, and social networks as explanations for retention. Inertia toward the material convoy maintains the availability and comfort of things, but it may also lead to a predicament wherein the collection becomes a worry for self and others. PMID:24518148

  17. Evaluating Multiethnic Materials.

    ERIC Educational Resources Information Center

    Garcia, Jesus

    The problem of identifying good ethnic studies materials is a result of the large amount of materials produced in the 1960s and of the currently renewed interest in ethnic studies. Four types of materials are available to elementary classroom teachers: ethnic information, single-ethnic approaches, minority or European-ethnic approaches, and…

  18. A research project to develop and evaluate a technical education component on materials technology for orientation to space-age technology

    NASA Technical Reports Server (NTRS)

    Jacobs, J. A.

    1976-01-01

    A project was initiated to develop, implement, and evaluate a prototype component for self-pacing, individualized instruction on basic materials science. Results of this project indicate that systematically developed, self-paced instruction provides an effective means for orienting nontraditional college students and secondary students, especially minorities, to both engineering technology and basic materials science. In addition, students using such a system gain greater chances for mastering subject matter than with conventional modes of instruction.

  19. Narayanaswamy's 1971 aging theory and material time.

    PubMed

    Dyre, Jeppe C

    2015-09-21

    The Bochkov-Kuzovlev nonlinear fluctuation-dissipation theorem is used to derive Narayanaswamy's phenomenological theory of physical aging, in which this highly nonlinear phenomenon is described by a linear material-time convolution integral. A characteristic property of the Narayanaswamy aging description is material-time translational invariance, which is here taken as the basic assumption of the derivation. It is shown that only one possible definition of the material time obeys this invariance, namely, the square of the distance travelled from a configuration of the system far back in time. The paper concludes with suggestions for computer simulations that test for consequences of material-time translational invariance. One of these is the "unique-triangles property" according to which any three points on the system's path form a triangle such that two side lengths determine the third; this is equivalent to the well-known triangular relation for time-autocorrelation functions of aging spin glasses [L. F. Cugliandolo and J. Kurchan, J. Phys. A: Math. Gen. 27, 5749 (1994)]. The unique-triangles property implies a simple geometric interpretation of out-of-equilibrium time-autocorrelation functions, which extends to aging a previously proposed framework for such functions in equilibrium [J. C. Dyre, e-print arXiv:cond-mat/9712222 (1997)]. PMID:26395719

  20. Narayanaswamy's 1971 aging theory and material time

    NASA Astrophysics Data System (ADS)

    Dyre, Jeppe C.

    2015-09-01

    The Bochkov-Kuzovlev nonlinear fluctuation-dissipation theorem is used to derive Narayanaswamy's phenomenological theory of physical aging, in which this highly nonlinear phenomenon is described by a linear material-time convolution integral. A characteristic property of the Narayanaswamy aging description is material-time translational invariance, which is here taken as the basic assumption of the derivation. It is shown that only one possible definition of the material time obeys this invariance, namely, the square of the distance travelled from a configuration of the system far back in time. The paper concludes with suggestions for computer simulations that test for consequences of material-time translational invariance. One of these is the "unique-triangles property" according to which any three points on the system's path form a triangle such that two side lengths determine the third; this is equivalent to the well-known triangular relation for time-autocorrelation functions of aging spin glasses [L. F. Cugliandolo and J. Kurchan, J. Phys. A: Math. Gen. 27, 5749 (1994)]. The unique-triangles property implies a simple geometric interpretation of out-of-equilibrium time-autocorrelation functions, which extends to aging a previously proposed framework for such functions in equilibrium [J. C. Dyre, e-print arXiv:cond-mat/9712222 (1997)].

  1. Creep and aging in jammed granular materials

    NASA Astrophysics Data System (ADS)

    Srivastava, Ishan; Fisher, Timothy

    Granular materials flow (or unjam) when stressed above the Coulomb yield stress, but a slow creep is observed when the applied stresses are low. In this work, using a recently introduced enthalpy-based variable-cell simulation method, we will present results on the creep and slow aging dynamics in granular systems comprised of soft particles of varying shape that are hydrostatically jammed and subjected to an external stress. We observe a two-stage creep with an initial fast exponential evolution followed by a slow logarithmic evolution over long time scales. We correlate the slow creeping dynamics with micromechanical evolution at the grain scale, such as increasing dynamical heterogeneity and force-chain rearrangements. Results will also be presented on the effect of grain shape (faceted vs. spherical) on the creep and aging dynamics. Finally, a continuum granular fluidity model is developed to rationalize these observations.

  2. Teaching and Learning About Aging. Evaluation Report.

    ERIC Educational Resources Information Center

    Peters, Eileen

    This evaluation study determined the extent to which teachers and students involved with the Teaching and Learning About Aging (TLA) project experienced cognitive growth and attitudinal change. The major purpose of the TLA project was to help students understand aging and related issues and to foster more positive attitudes toward aging and older…

  3. Spectral Age Dating of Volcanic Materials

    NASA Astrophysics Data System (ADS)

    Pearson, N.; Calvin, W. M.

    2015-12-01

    As part of the HyspIRI preparatory airborne campaign, high spectral resolution data of the Mono-Inyo craters had been collected. The Mono-Inyo Craters are a chain of geologically young craters that have been erupted over the past 40,000 years. We show a spectral variation in the 2.21μm absorption band depth (commonly associated with the Si-OH stretch) between craters of different ages. To explain this we propose the devitrification of the surface of the volcanic materials creating a weathering rind that thickens with age. A definite linear correlation between age and band depth is shown for craters less than 5,000 years old and potential logarithmic correlation for older craters. To help test this, hand samples from the craters were collected from several of the volcanic craters and the weathering rind thickness measured using a scanning electron microprobe. This correlation combined with a HyspIRI like dataset could be used to define volcanic hazards in large or remote regions, such as the Aleutian Island Arc or Kamchatka Peninsula.

  4. Material compatibility and thermal aging of thermoelectric materials.

    SciTech Connect

    Gardea, Andrew D.; Nishimoto, Ryan; Yang, Nancy Y. C.; Morales, Alfredo Martin; Whalen, Scott A.; Chames, Jeffrey M.; Clift, W. Miles

    2009-09-01

    In order to design a thermoelectric (TE) module suitable for long-term elevated temperature use, the Department 8651 has conducted parametric experiments to study material compatibility and thermal aging of TE materials. In addition, a comprehensive material characterization has been preformed to examine thermal stability of P- and N-based alloys and their interaction with interconnect diffusion barrier(s) and solder. At present, we have completed the 7-days aging experiments for 36 tiles, from ambient to 250 C. The thermal behavior of P- and N-based alloys and their thermal interaction with both Ni and Co diffusion barriers and Au-Sn solder were examined. The preliminary results show the microstructure, texture, alloy composition, and hardness of P-(Bi,Sb){sub 2}Te{sub 3} and N-Bi{sub 2}(Te,Se){sub 3} alloys are thermally stable up to 7 days annealing at 250 C. However, metallurgical reactions between the Ni-phosphor barriers and P-type base alloy were evident at temperatures {ge} 175 C. At 250 C, the depth (or distance) of the metallurgical reaction and/or Ni diffusion into P-(Bi,Sb){sub 2}Te{sub 3} is approximately 10-15 {micro}m. This thermal instability makes the Ni-phosphor barrier unsuitable for use at temperatures {ge} 175 C. The Co barrier appeared to be thermally stable and compatible with P(Bi,Sb){sub 2}Te{sub 3} at all annealing temperatures, with the exception of a minor Co diffusion into Au-Sn solder at {ge} 175 C. The effects of Co diffusion on long-term system reliability and/or the thermal stability of the Co barrier are yet to be determined. Te evaporation and its subsequent reaction with Au-Sn solder and Ni and Co barriers on the ends of the tiles at temperatures {ge} 175 C were evident. The Te loss and its effect on the long-term required stoichiometry of P-(Bi, Sb){sub 2}Te{sub 3} are yet to be understood. The aging experiments of 90 days and 180 days are ongoing and scheduled to be completed in 30 days and 150 days, respectively. Material

  5. Evaluation of Alkaline Cleaner Materials

    NASA Technical Reports Server (NTRS)

    Partz, Earl

    1998-01-01

    Alkaline cleaners used to process aluminum substrates have contained chromium as the corrosion inhibitor. Chromium is a hazardous substance whose use and control are described by environmental laws. Replacement materials that have the characteristics of chromated alkaline cleaners need to be found that address both the cleaning requirements and environmental impacts. This report will review environmentally friendly candidates evaluated as non-chromium alkaline cleaner replacements and methods used to compare those candidates one versus another. The report will also list characteristics used to select candidates based on their declared contents. It will also describe and evaluate methods used to discriminate among the large number of prospective candidates.

  6. DWPF MATERIALS EVALUATION SUMMARY REPORT

    SciTech Connect

    Gee, T.; Chandler, G.; Daugherty, W.; Imrich, K.; Jankins, C.

    1996-09-12

    To better ensure the reliability of the Defense Waste Processing Facility (DWPF) remote canyon process equipment, a materials evaluation program was performed as part of the overall startup test program. Specific test programs included FA-04 ('Process Vessels Erosion/Corrosion Studies') and FA-05 (melter inspection). At the conclusion of field testing, Test Results Reports were issued to cover the various test phases. While these reports completed the startup test requirements, DWPF-Engineering agreed to compile a more detailed report which would include essentially all of the materials testing programs performed at DWPF. The scope of the materials evaouation programs included selected equipment from the Salt Process Cell (SPC), Chemical Process Cell (CPC), Melt Cell, Canister Decon Cell (CDC), and supporting facilities. The program consisted of performing pre-service baseline inspections (work completed in 1992) and follow-up inspections after completion of the DWPF cold chemical runs. Process equipment inspected included: process vessels, pumps, agitators, coils, jumpers, and melter top head components. Various NDE (non-destructive examination) techniques were used during the inspection program, including: ultrasonic testing (UT), visual (direct or video probe), radiography, penetrant testing (PT), and dimensional analyses. Finally, coupon racks were placed in selected tanks in 1992 for subsequent removal and corrosion evaluation after chemical runs.

  7. Images of Aging in Selected Religious Education Curriculum Materials.

    ERIC Educational Resources Information Center

    Cram, Ronald H.

    Images of aging that appear in popular child/teen curricular materials used in church-related contexts were examined to determine how older adults are portrayed in words and pictures in these materials and what images of aging emerge. Materials from the following sources, randomly selected from those that had been checked out of the Ecumenical…

  8. Aging management of major LWR components with nondestructive evaluation

    SciTech Connect

    Shah, V.N.; MacDonald, P.E.; Akers, D.W.; Sellers, C.; Murty, K.L.; Miraglia, P.Q.; Mathew, M.D.; Haggag, F.M.

    1997-12-31

    Nondestructive evaluation of material damage can contribute to continued safe, reliable, and economical operation of nuclear power plants through their current and renewed license period. The aging mechanisms active in the major light water reactor components are radiation embrittlement, thermal aging, stress corrosion cracking, flow-accelerated corrosion, and fatigue, which reduce fracture toughness, structural strength, or fatigue resistance of the components and challenge structural integrity of the pressure boundary. This paper reviews four nondestructive evaluation methods with the potential for in situ assessment of damage caused by these mechanisms: stress-strain microprobe for determining mechanical properties of reactor pressure vessel and cast stainless materials, magnetic methods for estimating thermal aging damage in cast stainless steel, positron annihilation measurements for estimating early fatigue damage in reactor coolant system piping, and ultrasonic guided wave technique for detecting cracks and wall thinning in tubes and pipes and corrosion damage to embedded portion of metal containments.

  9. Computational Age Dating of Special Nuclear Materials

    SciTech Connect

    None, None

    2012-06-30

    This slide-show presented an overview of the Constrained Progressive Reversal (CPR) method for computing decays, age dating, and spoof detecting. The CPR method is: Capable of temporal profiling a SNM sample; Precise (compared with known decay code, such a ORIGEN); Easy (for computer implementation and analysis). We have illustrated with real SNM data using CPR for age dating and spoof detection. If SNM is pure, may use CPR to derive its age. If SNM is mixed, CPR will indicate that it is mixed or spoofed.

  10. Age as a Determinant of Interpersonal Evaluations.

    ERIC Educational Resources Information Center

    Scheier, Michael F.; Schulz, Richard

    This study focuses on the impact of age on interpersonal evaluation of persons, particularly the elderly as individuals and not as a group. Using a 75-year-old target and a 23-year-old target, the experimenter predicted and found support for the idea that personal information contained in a transcript would evoke sympathy, and thereby lead…

  11. The Empirical Evaluation of Language Teaching Materials.

    ERIC Educational Resources Information Center

    Ellis, Rod

    1997-01-01

    Distinguishes two types of materials evaluation: a predictive evaluation designed to make a decision regarding what materials to use, and a retrospective evaluation to examine materials already used. Describes a procedure for conducting task evaluations, suggesting that they constitute a kind of action research that can contribute to reflective…

  12. A mechanical property and stress corrosion evaluation of VIM-ESR-VAR work strengthened and direct double aged Inconel 718 bar material

    NASA Technical Reports Server (NTRS)

    Montano, J. W.

    1986-01-01

    Presented are the mechanical properties and the stress corrosion resistance of triple melted vacuum induction melted (VIM), electro-slag remelted (ESR), and vacuum arc remelted (VAR), solution treated, work strengthened and direct double aged Inconel 718 alloy bars 4.00 in. (10.16) and 5.75 in. (14.60 cm) diameter. Tensile, charpy v-notched impact, and compact tension specimens were tested at ambient temperature in both the longitudinal and transverse directions. Longitudinal tensile and yield strengths in excess of 220 ksi (1516.85 MPa) and 200 ksi (1378.00 MPa) respectively, were realized at ambient temperature. Additional charpy impact and compact tension tests were performed at -100 F (-73 C). Longitudinal charpy impact strength equalled or exceeded 12.0 ft-lbs (16.3 Joules) at ambient and at -100 F(-73 C) while longitudinal compact (LC) tension fracture toughness strength remained above 79 ksi (86.80 MPa) at ambient and at -100 F(-73 C) temperatures. No failures occurred in the longitudinal or transverse tensile specimens stressed to 75 and 100 percent of their respective yield strengths and exposed to a salt fog environment for 180 days. Tensile tests performed after the stress corrosion test indicated no mechanical property degradation.

  13. A mechanical property and stress corrosion evaluation of VIM-ESR-VAR work strengthened and direct double aged Inconel 718 bar material

    NASA Astrophysics Data System (ADS)

    Montano, J. W.

    1986-09-01

    Presented are the mechanical properties and the stress corrosion resistance of triple melted vacuum induction melted (VIM), electro-slag remelted (ESR), and vacuum arc remelted (VAR), solution treated, work strengthened and direct double aged Inconel 718 alloy bars 4.00 in. (10.16) and 5.75 in. (14.60 cm) diameter. Tensile, charpy v-notched impact, and compact tension specimens were tested at ambient temperature in both the longitudinal and transverse directions. Longitudinal tensile and yield strengths in excess of 220 ksi (1516.85 MPa) and 200 ksi (1378.00 MPa) respectively, were realized at ambient temperature. Additional charpy impact and compact tension tests were performed at -100 F (-73 C). Longitudinal charpy impact strength equalled or exceeded 12.0 ft-lbs (16.3 Joules) at ambient and at -100 F(-73 C) while longitudinal compact (LC) tension fracture toughness strength remained above 79 ksi (86.80 MPa) at ambient and at -100 F(-73 C) temperatures. No failures occurred in the longitudinal or transverse tensile specimens stressed to 75 and 100 percent of their respective yield strengths and exposed to a salt fog environment for 180 days. Tensile tests performed after the stress corrosion test indicated no mechanical property degradation.

  14. Nanomodification of Cementitious Materials: Fresh State and Early Age

    NASA Astrophysics Data System (ADS)

    Kawashima, Shiho

    Concrete is heterogeneous at all length scales and its microstructure evolves continuously over decades. Through the use of nanoparticles, it is possible to alter the microstructure of cementitious materials from within the first microsecond to control its rheological and eventual mechanical properties. The continued development of this technology hinges on adopting a materials science approach to achieve proper processing and measurement techniques, both of which are investigated in this study. Novel rheological methods are implemented to evaluate the fresh-state properties of cement pastes modified with nano-sized attapulgite clays. Previous studies have demonstrated that clays can reduce the lateral pressure exerted on formwork by self-consolidating concrete (SCC). It is hypothesized that this is tied to the influence of clays on two rheological properties of SCC: material cohesion and structural rebuilding. Therefore the effect of clays on adhesive properties is measured by the tack test and rate of rebuilding is evaluated by measuring relaxation time during creep. In addition, due to the complexity of cement rheology, i.e. simultaneous thixotropic rebuilding and hydration, the results are supplemented with a measure of the viscoelastic properties obtained through oscillatory shear rheometry. It is found that clays significantly increase cohesion and accelerate structural recovery of cement pastes. The results also indicate that the tack test is a suitable method for measuring the adhesive properties and structural evolution of cementitious materials in the fresh state. The potential of calcium carbonate (CaCO3) nanoparticles in improving the early-age properties of fly ash-cement pastes is investigated. The focus is on dispersing the CaCO3 nanoparticles to enhance their effect and limit the addition level necessary. The selected approach involves sonication in an aqueous medium and use of surfactant. Degree of dispersion and stability are quantitatively

  15. Space shuttle nonmetallic materials age life prediction

    NASA Technical Reports Server (NTRS)

    Mendenhall, G. D.; Hassell, J. A.; Nathan, R. A.

    1975-01-01

    The chemiluminescence from samples of polybutadiene, Viton, Teflon, Silicone, PL 731 Adhesive, and SP 296 Boron-Epoxy composite was measured at temperatures from 25 to 150 C. Excellent correlations were obtained between chemiluminescence and temperature. These correlations serve to validate accelerated aging tests (at elevated temperatures) designed to predict service life at lower temperatures. In most cases, smooth or linear correlations were obtained between chemiluminescence and physical properties of purified polymer gums, including the tensile strength, viscosity, and loss tangent. The latter is a complex function of certain polymer properties. Data were obtained with far greater ease by the chemiluminescence technique than by the conventional methods of study. The chemiluminescence from the Teflon (Halon) samples was discovered to arise from trace amounts of impurities, which were undetectable by conventional, destructive analysis of the sample.

  16. Constitutive equations of ageing polymeric materials

    NASA Technical Reports Server (NTRS)

    Peng, S. T. J.

    1985-01-01

    The constitutive equation for the relaxation behavior of time-dependent, chemically unstable materials developed by Valanis and Peng (1983), which used the irreversible thermodynamics of internal variables in Eyring's absolute reaction theory and yielded a theoretical expression for the effect of chemical crosslink density on the relaxation rate, is presently applied to the creep behavior of a network polymer which is undergoing a scission process. In particular, two equations are derived which may for the first time show the relations between mechanical models and internal variables in the creep expressions, using a three-element model with a Maxwell element.

  17. Evaluation of aging degradation of structural components

    SciTech Connect

    Chopra, O.K.; Shack, W.J.

    1992-03-01

    Irradiation embrittlement of the neutron shield tank (NST) A212 Grade B steel from the Shippingport reactor, as well as thermal embrittlement of CF-8 cast stainless steel components from the Shippingport and KRB reactors, has been characterized. Increases in Charpy transition temperature (CTT), yield stress, and hardness of the NST material in the low-temperature low-flux environment are consistent with the test reactor data for irradiations at < 232{degrees}C. The shift in CTT is not as severe as that observed in surveillance samples from the High Flux Isotope Reactor (HFIR): however, it shows very good agreement with the results for HFIR A212-B steel irradiated in the Oak Ridge Research Reactor. The results indicate that fluence rate has not effect on radiation embrittlement at rates as low as 2 {times} 10{sup 8} n/cm{sup 2}{center dot}s at the low operating temperature of the Shippingport NST, i.e., 55{degrees}C. This suggest that radiation damage in Shippingport NST and HFIR surveillance samples may be different because of the neutron spectra and/or Cu and Ni content of the two materials. Cast stainless steel components show relatively modest decreases in fracture toughness and Charpy-impact properties and a small increase in tensile strength. Correlations for estimating mechanical properties of cast stainless steels predict accurate or slightly conservative values for Charpy-impact energy, tensile flow stress, fracture toughness J-R curve, and J{sub IC} of the materials. The kinetics of thermal embrittlement and degree of embrittlement at saturation, i.e., the minimum impact energy achieved after long-term aging, were established from materials that were aged further in the laboratory. The results were consistent with the estimates. The correlations successfully predict the mechanical properties of the Ringhals 2 reactor hot- and crossover-leg elbows (CF-8M steel) after service of {approx}15 y.

  18. Evaluation of aging degradation of structural components

    SciTech Connect

    Chopra, O.K.; Shack, W.J.

    1992-03-01

    Irradiation embrittlement of the neutron shield tank (NST) A212 Grade B steel from the Shippingport reactor, as well as thermal embrittlement of CF-8 cast stainless steel components from the Shippingport and KRB reactors, has been characterized. Increases in Charpy transition temperature (CTT), yield stress, and hardness of the NST material in the low-temperature low-flux environment are consistent with the test reactor data for irradiations at < 232{degrees}C. The shift in CTT is not as severe as that observed in surveillance samples from the High Flux Isotope Reactor (HFIR): however, it shows very good agreement with the results for HFIR A212-B steel irradiated in the Oak Ridge Research Reactor. The results indicate that fluence rate has not effect on radiation embrittlement at rates as low as 2 {times} 10{sup 8} n/cm{sup 2}{center_dot}s at the low operating temperature of the Shippingport NST, i.e., 55{degrees}C. This suggest that radiation damage in Shippingport NST and HFIR surveillance samples may be different because of the neutron spectra and/or Cu and Ni content of the two materials. Cast stainless steel components show relatively modest decreases in fracture toughness and Charpy-impact properties and a small increase in tensile strength. Correlations for estimating mechanical properties of cast stainless steels predict accurate or slightly conservative values for Charpy-impact energy, tensile flow stress, fracture toughness J-R curve, and J{sub IC} of the materials. The kinetics of thermal embrittlement and degree of embrittlement at saturation, i.e., the minimum impact energy achieved after long-term aging, were established from materials that were aged further in the laboratory. The results were consistent with the estimates. The correlations successfully predict the mechanical properties of the Ringhals 2 reactor hot- and crossover-leg elbows (CF-8M steel) after service of {approx}15 y.

  19. Quality evaluation of aged concrete by ultrasound

    NASA Astrophysics Data System (ADS)

    Tavossi, H. M.; Tittmann, Bernhard R.; Cohen-Tenoudji, Frederic

    1999-02-01

    The velocity, attenuation and scattering of ultrasonic waves measured in concrete, mortar and cement structures can be used to evaluate their quality with weathering and aging. In this investigation the hardening of concrete mixture with time is monitored by ultrasonic waves under different conditions of temperature and water to cement ratio. The measured ultrasonic parameters can then be utilized to determine the final quality of the completely cured concrete structure from initial measurement. The quality of a concrete structure is determined by its resistance to compression and its rigidity, which should be within the acceptable values required by the design specifications. The internal and external flaws that could lower its strength can also be detected by ultrasonic technique. Aging process of concrete by weathering can be simulated in the laboratory by subjecting the concrete to extremes of cold and hot cycles in the range of temperatures normally encountered in summer and winter. In this research ultrasonic sensors in low frequency range of 40 to 100 kHz are used to monitor the quality of concrete. Ultrasonic pulses transmitted through the concrete sample are recorded for analysis in time and frequency domains. ULtrasonic waves penetration in concrete of the order of few feet has been achieved in laboratory. Data analyses on ultrasonic signal velocity, spectral content, phase and attenuation, can be utilized to evaluate, in situ, the quality and mechanical strength of concrete.

  20. Evaluation of Locally Produced Materials

    ERIC Educational Resources Information Center

    Gale, Fred

    1976-01-01

    Describes conditions important to the assessment process in the development of instructional materials. Out of these conditions several questions were suggested as key check points in the assessment model. (Author/RK)

  1. Electrostatic Evaluation: SCAPE Suit Materials

    NASA Technical Reports Server (NTRS)

    Buhler, Charles; Calle, Carlos

    2005-01-01

    The surface resistivity tests are performed per the requirements of the ESD Association Standard Test Method ESD STM11.11*. These measurements are taken using a PRS-801 resistance system with an Electro Tech System (ETS) PRF-911 concentric ring resistance probe. The tests require a five pound weight on top of cylindrical electrodes and were conducted at both ambient and low humidity conditions. In order for materials to "pass" resistivity tests the surface of the materials must either be conductive or statically dissipative otherwise the materials "fail" ESD. Volume resistivity tests are also conducted to measure conductivity through the material as opposed to conductivity along the surface. These tests are conducted using the same PRS-801 resistance system with the Electro Tech System PRF-911 concentric ring resistance probe but are performed in accordance with ESD Association Standard Test Method ESD STM11.l2**.

  2. LIGA microsystems aging : evaluation and mitigation.

    SciTech Connect

    Cadden, Charles H.; Yang, Nancy Y. C.; San Marchi, Christopher W.

    2003-12-01

    The deployment of LIGA structures in DP applications requires a thorough understanding of potential long term physical and chemical changes that may occur during service. While these components are generally fabricated from simple metallic systems such as copper, nickel and nickel alloys, the electroplating process used to form them creates microstructural features which differ from those found in conventional (e.g. ingot metallurgy) processing of such materials. Physical changes in non-equilibrium microstructures may occur due to long term exposure to temperatures sufficient to permit atomic and vacancy mobility. Chemical changes, particularly at the surfaces of LIGA parts, may occur in the presence of gaseous chemical species (e.g. water vapor, HE off-gassing compounds) and contact with other metallic structures. In this study, we have characterized the baseline microstructure of several nickel-based materials that are used to fabricate LIGA structures. Solute content and distribution was found to have a major effect on the electroplated microstructures. Microstructural features were correlated to measurements of hardness and tensile strength. Dormancy testing was conducted on one of the baseline compositions, nickel-sulfamate. Groups of specimens were exposed to controlled thermal cycles; subsequent examinations compared properties of 'aged' specimens to the baseline conditions. Results of our testing indicate that exposure to ambient temperatures (-54 C to 71 C) do not result in microstructural changes that might be expected to significantly effect mechanical performance. Additionally, no localized changes in surface appearance were found as a result of contact between electroplated parts.

  3. Evaluation of optical materials samples

    NASA Astrophysics Data System (ADS)

    1988-07-01

    The primary objective of order subcontract was to prepare AGT and UGT test specimens, provide characterization data and provide damage assessments on tech base laser mirror materials being developed on other government contracts. The properties to be determined included flexural strength, Young's modulus, Poisson's ratio, fracture toughness (KIc), coefficient of thermal expansion, thermal diffusivity, hardness, and specific heat. In some cases Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), energy dispersive X-ray analysis (EDAX), and Auger spectroscopy (AES) were to be performed to determine chemical composition and crystal structure and damage mechanisms. In addition if materials problems occurred, that could not be anticipated in advance, studies were to be initiated to aid the SDI optical materials efforts as required.

  4. Developing and Evaluating Patient Education Materials.

    ERIC Educational Resources Information Center

    Monsivais, Diane; Reynolds, Audree

    2003-01-01

    Discusses the rationale for nurse involvement in the development of patient education materials. Presents guidelines for evaluating existing material, including print and web resources, for credibility and readability. Makes recommendations for rewriting material at an easier-to-read level. (SK)

  5. Aging mechanisms in amorphous phase-change materials

    NASA Astrophysics Data System (ADS)

    Raty, Jean Yves; Zhang, Wei; Luckas, Jennifer; Chen, Chao; Mazzarello, Riccardo; Bichara, Christophe; Wuttig, Matthias

    2015-06-01

    Aging is a ubiquitous phenomenon in glasses. In the case of phase-change materials, it leads to a drift in the electrical resistance, which hinders the development of ultrahigh density storage devices. Here we elucidate the aging process in amorphous GeTe, a prototypical phase-change material, by advanced numerical simulations, photothermal deflection spectroscopy and impedance spectroscopy experiments. We show that aging is accompanied by a progressive change of the local chemical order towards the crystalline one. Yet, the glass evolves towards a covalent amorphous network with increasing Peierls distortion, whose structural and electronic properties drift away from those of the resonantly bonded crystal. This behaviour sets phase-change materials apart from conventional glass-forming systems, which display the same local structure and bonding in both phases.

  6. Heliostat materials development and evaluation

    NASA Astrophysics Data System (ADS)

    1980-05-01

    Both UV stabilized poly (ethylene terephthalate) (PET) polyvinylidiene fluoride films were produced, characterized, and tested to establish a data base of predicting life cycles and upgrading the cost/performance ratio of heliostat enclosures. Laminated aluminized PET, protected and unprotected by a thin layer of resin was studied as suitable reflector material. Procedures and results of weathering tests are presented. Methods for bonding plastic films, specularly optimized film reflectors, and the mechanism of a weathering degradation are discussed. Data on the flammability of plastic films are included.

  7. Narayanaswamy’s 1971 aging theory and material time

    SciTech Connect

    Dyre, Jeppe C.

    2015-09-21

    The Bochkov-Kuzovlev nonlinear fluctuation-dissipation theorem is used to derive Narayanaswamy’s phenomenological theory of physical aging, in which this highly nonlinear phenomenon is described by a linear material-time convolution integral. A characteristic property of the Narayanaswamy aging description is material-time translational invariance, which is here taken as the basic assumption of the derivation. It is shown that only one possible definition of the material time obeys this invariance, namely, the square of the distance travelled from a configuration of the system far back in time. The paper concludes with suggestions for computer simulations that test for consequences of material-time translational invariance. One of these is the “unique-triangles property” according to which any three points on the system’s path form a triangle such that two side lengths determine the third; this is equivalent to the well-known triangular relation for time-autocorrelation functions of aging spin glasses [L. F. Cugliandolo and J. Kurchan, J. Phys. A: Math. Gen. 27, 5749 (1994)]. The unique-triangles property implies a simple geometric interpretation of out-of-equilibrium time-autocorrelation functions, which extends to aging a previously proposed framework for such functions in equilibrium [J. C. Dyre, e-print arXiv:cond-mat/9712222 (1997)].

  8. International Law in a Global Age. Student Materials.

    ERIC Educational Resources Information Center

    Croddy, Marshall; Maxey, Phyllis

    This global approach to teaching high school students about international law uses existing curriculum materials from a variety of social studies disciplines to present five major perspectives. Perspective I "Global Links," focuses on the meaning of citizenship in a global age and the interconnectedness between individuals and the international…

  9. Aging characteristics of short glass fiber reinforced ZA-27 alloy composite materials

    NASA Astrophysics Data System (ADS)

    Sharma, S. C.; Girish, B. M.; Satish, B. M.; Kamath, R.

    1998-12-01

    Aging characteristics of short glass fiber reinforced ZA-27 alloy composite materials have been evaluated in the present study. The liquid metallurgy technique was used to fabricate the composites, in which preheated short glass fibers were introduced into the ZA-27 alloy melt above its liquidus temperature. The aging temperature employed was 125 °C for 6, 12,18, and 24 h. The aged alloy (no fibers) reached the peak hardness after 18 h, while the composites (regardless of filler content) reached the same hardness in 12 h. It is hypothesized that the aging treatment of a composite improves the strength of the interface between the short fibers and the matrix. This is confirmed by the tensile fractograph analysis, which indicates that at a given aging temperature, the composites aged for 18 h exhibit short fibers that remain attached to the metal matrix, while those aged for 6 h undergo debonding.

  10. Reinterpreting Evaluation Classics in the Modern Age.

    ERIC Educational Resources Information Center

    Adams, Joan Duncan

    2001-01-01

    Analyzes features of impact evaluation models by Kirkpatrick, Grotelueschen, Cervero, Robinson and Robinson, and Jackson. Incorporates features into the Behaviorally Based Impact Evaluation Model, designed for evaluating continuing professional education outcomes in corporate settings. Contains 23 references. (SK)

  11. Aging behavior of polymeric solar absorber materials: Aging on the component level

    SciTech Connect

    Kahlen, S.; Wallner, G.M.; Lang, R.W.; Meir, M.; Rekstad, J.

    2010-03-15

    Within this study, the aging behavior of a PPE + PS absorber material was investigated on the absorber component level. To indicate aging, characteristic mechanical values were determined by indentation tests of specimens taken from components and exposed to laboratory aging (140 C in air, 80 C in water) and service near outdoor aging conditions (stagnation in northern climate). In addition to the mechanical tests, the unaged and aged specimens were also characterized thermo-analytically via differential scanning calorimetry (DSC). The results indicate that reductions in both characteristic mechanical values of the indentation tests, i.e., load of the first transition and ultimate indentation, reflect at least some physical aging although chemical aging may also be of importance based on previous analytical investigations of laboratory aged polymer films. While laboratory aging in air at 140 C and service exposure at a test facility in Oslo (N) under stagnation conditions led to a significant reduction in the mechanical indentation resistance, no influence of laboratory aging in water at 80 C on the mechanical behavior of the absorber sheet was found. Depending on the ultimate failure criterion applied (reduction of characteristic mechanical values to 80% and 50%, respectively), the technical service life found for hot air laboratory and stagnation service conditions was found to be less than 51 and 159 h, respectively. As these durations are significantly below the estimated stagnation conditions accumulated in the desired operation lifetime for such a collector, the PPE + PS type investigated does not seem to be a proper material candidate for solar thermal absorbers. Finally, based on the results obtained, a relation between laboratory aging time in air at 140 C and cumulated irradiation energy during exposure on the test facility in Oslo was established. (author)

  12. Thermal Protection Materials: Development, Characterization and Evaluation

    NASA Technical Reports Server (NTRS)

    Johnson, Silvia M.

    2012-01-01

    Thermal protection materials and systems (TPS) are used to protect space vehicles from the heat experienced during entry into an atmosphere. The application for these materials is very specialized as are the materials. They must have specific properties to withstand conditions during specific entries. There is no one-size-fits-all TPS as the conditions experienced by a material are very dependent upon the atmosphere, the entry speed, the size and shape of the vehicle, and the location on the vehicle. However, all TPS must be reliable and efficient to ensure mission safety, that is to protect the vehicle while ensuring that payload is maximized. Types of TPS will be reviewed in relation to types of missions and applications. Both reusable and ablative materials will be discussed. Approaches to characterizing and evaluating these materials will be presented. The role of heritage versus new materials will be described.

  13. Physical properties of three maxillofacial materials as a function of accelerated aging.

    PubMed

    Dootz, E R; Koran, A; Craig, R G

    1994-04-01

    This study compares the tensile strength, elongation, Shore-A hardness, and tear resistance of three silicone maxillofacial materials before and after aging to provide comparative data for evaluation of new or experimental elastomers. The materials evaluated were MDX-4-4210, Factor II (A-2186), and Cosmesil. Tests were conducted 24 hours after specimen preparation and were repeated after aging for 900 hours in a Weather-Ometer device. Five samples were made for each material under all test conditions. After testing, mean values were calculated for all materials under all test conditions and were compared by two-way analysis of variance and Tukey intervals at p < or = 0.05. PMID:8196002

  14. Composite Overwrapped Pressure Vessels (COPV) Materials Aging Issues

    NASA Technical Reports Server (NTRS)

    2010-01-01

    This slide presentation reviews some of the issues concerning the aging of the materials in a Composite Overwrapped Pressure Vessels (COPV). The basic composition of the COPV is a Boss, a composite overwrap, and a metallic liner. The lifetime of a COPV is affected by the age of the overwrap, the cyclic fatigue of the metallic liner, and stress rupture life, a sudden and catastrophic failure of the overwrap while holding at a stress level below the ultimate strength for an extended time. There is information about the coupon tests that were performed, and a test on a flight COPV.

  15. Evaluation of Speakers at CME: Cosmecon 2006, An International Conference on Ageing and Anti-ageing

    PubMed Central

    Vijayashankar MR

    2008-01-01

    Aim: To determine what constitutes effective or ineffective lecturing in dermatological conferences and also the utility of a scientific programme for the dermatologists. Methods and Materials: Evaluation forms were circulated to delegates attending the Cosmecon conference on ageing and anti-ageing, held in July 2006 at Bangalore. Feedback from the delegates in the form of completed evaluation forms of individual speakers and each session of the 3-day conference Cosmecon (including the live workshop on aesthetic and surgical procedures) were studied. Comments were analysed with the help of a biostatistician to determine the positive and negative responses. Results: On day 1 of the conference, workshop included 14 procedures by different specialists and on the second and third days of the conference, there were a total of 10 sessions, with five on each day. Evaluation forms were handed out to 440 delegates on day 1 and 600 delegates on days 2 and 3. Fifty-five speakers were evaluated by an average 56 delegates out of 440 delegates on day 1 and 600 delegates on the second and third days. The delegate response to completing the evaluation form was poor. Only about 25% of the delegates completed the feedback forms. However, the feedback did give some insight to the scientific programme, on both positive and negative aspects. Most delegates stated that they benefited from the presentations. The main negative response was lack of opportunity to ask questions after a lecture. The main positive comment was that the time keeping in the conference was very good. Conclusion: The response of the delegates in providing feedback was poor. Efforts have to be made to educate and encourage delegates to complete the feedback forms. Systematic review of the speakers would provide information to design future CME programmes effectively and to incorporate improvements for effective lecturing and to avoid ineffective lectures. The CME evaluation can also help the organizers to provide

  16. Investigation of Hygro-Thermal Aging on Carbon/Epoxy Materials for Jet Engine Fan Sections

    NASA Technical Reports Server (NTRS)

    Kohlman, Lee W.; Roberts, Gary D.; Miller, Sandi G.; Pereira, J. Michael

    2011-01-01

    This poster summarizes 2 years of aging on E862 epoxy and E862 epoxy with triaxial braided T700s carbon fiber composite. Several test methods were used to characterize chemical, physical, and mechanical properties of both the resin and composite materials. The aging cycle that was used included varying temperature and humidity exposure. The goal was to evaluate the environmental effects on a potential jet engine fan section material. Some changes were noted in the resin which resulted in increased brittleness, though this did not significantly affect the tensile and impact test results. A potential decrease in compression strength requires additional investigation.

  17. Age-Related Differences in Evaluating Developmental Stability

    ERIC Educational Resources Information Center

    Mustafic, Maida; Freund, Alexandra M.

    2013-01-01

    Two studies examined the hypothesis that the evaluation of developmental stability changes across adulthood. Results of Study 1 ("N" = 119) supported the expectation that older adults ("M"[subscript age] = 65.29 years)--compared to younger ("M"[subscript age] = 23.38 years) and middle-aged adults…

  18. Radiocarbon dating of marine material: mollusc versus foraminifera ages

    NASA Astrophysics Data System (ADS)

    Callard, L.; Long, A. J.; Plets, R. M.; Cooper, A.; Belknap, D. F.; Edwards, R.; Jackson, D.; Kelley, J. T.; Long, D.; Milne, G. A.; Monteys, X.; Quinn, R.

    2013-12-01

    A key challenge in reconstructing Quaternary environmental change from marine archives is developing a robust chronology. During the last ~50k a-1, radiocarbon dating is the mainstay for many studies. Often investigators are restricted in the material that is available for dating, with studies relying on AMS dating of either mono-specific or mixed assemblages of foraminifera. In some instances, marine molluscs (broken or whole, articulated or disarticulated) may also be present and can provide an alternative or complementary dating target. Previous radiocarbon dating of paired foraminiferal and marine molluscan samples from the Kattegat (Denmark) revealed significant age offsets between these materials, inferred to reflect greater reworking of foraminifera compared to the marine molluscs (Heier-Nielsen et al., 1995). Here we present the results of a comparable study from the Irish Sea Basin, which forms part of a wider investigation into the evidence for the Late Glacial sea-level minima at offshore sites from around Britain and Ireland. We have collected and AMS 14C-dated twelve paired samples of foraminifera and marine shells. The results shows a systematic age offset with the monospecific foraminifera samples consistently giving older ages than their shell counterparts. This offset increases with sample age, reaching a maximum offset of 3000 years in the oldest sample (~ 13 ka cal a BP). These results are consistent with the observations of Heier-Nielsen et al. (1995), and we hypothesize that foraminifera may be more susceptible to reworking from older deposits because of their lower effective density than the shell samples. However, foraminifera size and shape may also be contributing factors. These findings are potentially significant for studies that develop chronologies based on radiocarbon dating of foraminifera alone, since the resulting dates may over-estimate sample age by several thousand years. We conclude by outlining an experimental design that seeks

  19. An evaluation of candidate oxidation resistant materials

    NASA Technical Reports Server (NTRS)

    Rutledge, Sharon; Banks, Bruce; Mirtich, Michael; Difilippo, Frank; Hotes, Deborah; Labed, Richard; Dever, Terese; Kussmaul, Michael

    1987-01-01

    Ground based testing of materials considered for Kapton solar array blanket protection, graphite epoxy structural member protection, and high temperature radiators was performed in an RF plasma asher. Ashing rates for Kapton were correlated with rates measured on STS-8 to determine the exposure time equivalent to one year in low Earth orbit (LEO) at a constant density space station orbital flux. Protective coatings on Kapton from Tekmat, Andus Corporation, and LeRC were evaluated in the plasma asher and mass loss rates per unit area were measured for each sample. All samples evaluated provided some protection to the underlying surface but ion beam sputter deposited samples of SiO2 and SiO2 with 8% polytetrafluoroethylene (PTFE) showed no evidence of degradation after 47 hours of exposure. Mica paint was evaluated as a protective coating for graphite epoxy structural members. Mica appears to be resistant to attack by atomic oxygen but only offers some limited protection as a paint because the paint vehicles evaluated to date were not resistant to atomic oxygen. Four materials were selected for evaluation as candidate radiator materials: stainless steel, copper, niobium-1% zirconium, and titanium-6% aluminum-4% vanadium. These materials were surface textured by various means to improve their emittance. Emittances as high as 0.93 at 2.5 microns for stainless steel and 0.89 at 2.5 microns for Nb-1 Zr were obtained from surface texturing. There were no significant changes in emittance after asher exposure.

  20. Evaluating Materials About Africa for Children.

    ERIC Educational Resources Information Center

    Schmidt, Nancy J.

    Choosing texts, media, and literature about Africa is a difficult task for school librarians who have not studied Africa in detail; however it is possible to evaluate the available materials on the basis of several important criteria. These include the authority of the author, the dates of preparation and publication, and the accuracy of…

  1. ASC Supercomputers Predict Effects of Aging on Materials

    SciTech Connect

    Kubota, A; Reisman, D B; Wolfer, W G

    2005-08-25

    In an extensive molecular dynamics (MD) study of shock compression of aluminum containing such microscopic defects as found in aged plutonium, LLNL scientists have demonstrated that ASC supercomputers live up to their promise as powerful tools to predict aging phenomena in the nuclear stockpile. Although these MD investigations are carried out on material samples containing only about 10 to 40 million atoms, and being not much bigger than a virus particle, they have shown that reliable materials properties and relationships between them can be extracted for density, temperature, pressure, and dynamic strength. This was proven by comparing their predictions with experimental data of the Hugoniot, with dynamic strength inferred from gas-gun experiments, and with the temperatures behind the shock front as calculated with hydro-codes. The effects of microscopic helium bubbles and of radiation-induced dislocation loops and voids on the equation of state were also determined and found to be small and in agreement with earlier theoretical predictions and recent diamond-anvil-cell experiments. However, these microscopic defects play an essential role in correctly predicting the dynamic strength for these nano-crystalline samples. These simulations also prove that the physics involved in shock compression experiments remains the same for macroscopic specimens used in gas-gun experiments down to micrometer samples to be employed in future NIF experiments. Furthermore, a practical way was discovered to reduce plastic instabilities in NIF target materials by introducing finely dispersed defects.

  2. Evaluation of dental age in protein energy malnutrition children

    PubMed Central

    Kumar, Vinod; Patil, Kavitha; Munoli, Karishma

    2015-01-01

    Background: Knowledge of dental age is very essential for a dental practitioner in planning treatment and it is a supplementary source of information for Pediatrician, Orthopedician and Endocrinologist. There are few studies in the literature about the comparison of dental with chronological age in protein energy malnutrition children (PEM). Accordingly, the aim of this study was to evaluate and compare dental age and chronological age in PEM children. Aims and Objective: To determine and compare dental age and chronological age in PEM children. Methods: A total of 100 PEM children within the age range of 6–12 years were selected. Chronological age was recorded using date of birth. Dental age was assessed by Demirjian's method using orthopantomogram. Comparison of two ages was done using the unpaired Student's t-test and Pearson's correlation coefficient. Results: Dental age was retarded compared to chronological age, and the difference was statistically significant (P < 0.001). The correlations between two ages were positive in both sexes. Conclusion: Dental age was delayed in our sample of 100 PEM children. Dental age can be considered as variable for diagnosing growth retardation in PEM children. Further studies are required to support our findings. PMID:26538919

  3. Application of Raman Spectroscopy for Nondestructive Evaluation of Composite Materials

    NASA Technical Reports Server (NTRS)

    Washer, Glenn A.; Brooks, Thomas M. B.; Saulsberry, Regor

    2007-01-01

    This paper will present an overview of efforts to investigate the application of Raman spectroscopy for the characterization of Kevlar materials. Raman spectroscopy is a laser technique that is sensitive to molecular interactions in materials such as Kevlar, graphite and carbon used in composite materials. The overall goal of this research reported here is to evaluate Raman spectroscopy as a potential nondestructive evaluation (NDE) tool for the detection of stress rupture in Kevlar composite over-wrapped pressure vessels (COPVs). Characterization of the Raman spectra of Kevlar yarn and strands will be presented and compared with analytical models provided in the literature. Results of testing to investigate the effects of creep and high-temperature aging on the Raman spectra will be presented.

  4. The rules of implicit evaluation by race, religion, and age.

    PubMed

    Axt, Jordan R; Ebersole, Charles R; Nosek, Brian A

    2014-09-01

    The social world is stratified. Social hierarchies are known but often disavowed as anachronisms or unjust. Nonetheless, hierarchies may persist in social memory. In three studies (total N > 200,000), we found evidence of social hierarchies in implicit evaluation by race, religion, and age. Participants implicitly evaluated their own racial group most positively and the remaining racial groups in accordance with the following hierarchy: Whites > Asians > Blacks > Hispanics. Similarly, participants implicitly evaluated their own religion most positively and the remaining religions in accordance with the following hierarchy: Christianity > Judaism > Hinduism or Buddhism > Islam. In a final study, participants of all ages implicitly evaluated age groups following this rule: children > young adults > middle-age adults > older adults. These results suggest that the rules of social evaluation are pervasively embedded in culture and mind. PMID:25079218

  5. Characterization and damage evaluation of advanced materials

    NASA Astrophysics Data System (ADS)

    Mitrovic, Milan

    Mechanical characterization of advanced materials, namely magnetostrictive and graphite/epoxy composite materials, is studied in this dissertation, with an emphasis on damage evaluation of composite materials. Consequently, the work in this dissertation is divided into two parts, with the first part focusing on characterization of the magneto-elastic response of magnetostrictlve materials, while the second part of this dissertation describes methods for evaluating the fatigue damage in composite materials. The objective of the first part of this dissertation is to evaluate a nonlinear constitutive relation which more closely depict the magneto-elastic response of magnetostrictive materials. Correlation between experimental and theoretical values indicate that the model adequately predicts the nonlinear strain/field relations in specific regimes, and that the currently employed linear approaches are inappropriate for modeling the response of this material in a structure. The objective of the second part of this dissertation is to unravel the complexities associated with damage events associated with polymeric composite materials. The intent is to characterize and understand the influence of impact and fatigue induced damage on the residual thermo-mechanical properties and compressive strength of composite systems. The influence of fatigue generated matrix cracking and micro-delaminations on thermal expansion coefficient (TEC) and compressive strength is investigated for woven graphite/epoxy composite system. Experimental results indicate that a strong correlation exists between TEC and compressive strength measurements, indicating that TEC measurements can be used as a damage metric for this material systems. The influence of delaminations on the natural frequencies and mode shapes of a composite laminate is also investigated. Based on the changes of these parameters as a function of damage, a methodology for determining the size and location of damage is suggested

  6. Electrochemical migration technique to accelerate ageing of cementitious materials

    NASA Astrophysics Data System (ADS)

    Babaahmadi, A.; Tang, L.; Abbas, Z.

    2013-07-01

    Durability assessment of concrete structures for constructions in nuclear waste repositories requires long term service life predictions. As deposition of low and intermediate level radioactive waste (LILW) takes up to 100 000 years, it is necessary to analyze the service life of cementitious materials in this time perspective. Using acceleration methods producing aged specimens would decrease the need of extrapolating short term data sets. Laboratory methods are therefore, needed for accelerating the ageing process without making any influencing distortion in the properties of the materials. This paper presents an electro-chemical migration method to increase the rate of calcium leaching from cementitious specimens. This method is developed based on the fact that major long term deterioration process of hardened cement paste in concrete structures for deposition of LILW is due to slow diffusion of calcium ions. In this method the cementitious specimen is placed in an electrochemical cell as a porous path way through which ions can migrate at a rate far higher than diffusion process. The electrical field is applied to the cell in a way to accelerate the ion migration without making destructions in the specimen's micro and macroscopic properties. The anolyte and catholyte solutions are designed favoring dissolution of calcium hydroxide and compensating for the leached calcium ions with another ion like lithium.

  7. Characterization and Evaluation of Aged Chromium Nickel Niobium Stainless Steels

    NASA Astrophysics Data System (ADS)

    Dewar, Matthew

    20Cr-32Ni-1Nb stainless steel alloys are commonly used in hydrogen reformer manifolds for transporting hot hydrogen by-products at 750-950°C. After long periods of exposure, embrittling secondary carbides and intermetallic phases can precipitate at the grain boundaries which can drastically reduce the ductility, and the repair weldability of the alloy. The intermetallic silicide, G-phase, is commonly observed in 20Cr-32Ni-1Nb stainless steels, and is prone to liquation cracking during welding operations. G-phase is deleterious to the material, where a high degree of G-phase coarsening will render the material unweldable. The present work will investigate various methods in mitigating G-phase precipitation. Variations in casting methods, wall thickness, homogenization treatments, and alloy chemistry will be examined by evaluating their microstructure after periodically aging the samples. Thermodynamic equilibrium modeling using computational thermodynamic tools will be used to optimize the 20Cr-32Ni-1Nb chemistry following ASTM specifications.

  8. Materials Compatibility and Aging for Flux and Cleaner Combinations.

    SciTech Connect

    Archuleta, Kim; Piatt, Rochelle

    2015-01-01

    A materials study of high reliability electronics cleaning is presented here. In Phase 1, mixed type substrates underwent a condensed contaminants application to view a worst- case scenario for unremoved flux with cleaning agent residue for parts in a silicone oil filled environment. In Phase 2, fluxes applied to copper coupons and to printed wiring boards underwent gentle cleaning then accelerated aging in air at 65% humidity and 30 O C. Both sets were aged for 4 weeks. Contaminants were no-clean (ORL0), water soluble (ORH1 liquid and ORH0 paste), and rosin (RMA; ROL0) fluxes. Defluxing agents were water, solvents, and engineered aqueous defluxers. In the first phase, coupons had flux applied and heated, then were placed in vials of oil with a small amount of cleaning agent and additional coupons. In the second phase, pairs of copper coupons and PWB were hand soldered by application of each flux, using tin-lead solder in a strip across the coupon or a set of test components on the PWB. One of each pair was cleaned in each cleaning agent, the first with a typical clean, and the second with a brief clean. Ionic contamination residue was measured before accelerated aging. After aging, substrates were removed and a visual record of coupon damage made, from which a subjective rank was applied for comparison between the various flux and defluxer combinations; more corrosion equated to higher rank. The ORH1 water soluble flux resulted in the highest ranking in both phases, the RMA flux the least. For the first phase, in which flux and defluxer remained on coupons, the aqueous defluxers led to worse corrosion. The vapor phase cleaning agents resulted in the highest ranking in the second phase, in which there was no physical cleaning. Further study of cleaning and rinsing parameters will be required.

  9. The difficult issue of age assessment on pedo-pornographic material.

    PubMed

    Cattaneo, Cristina; Ritz-Timme, Stefanie; Gabriel, Peter; Gibelli, Daniele; Giudici, Elena; Poppa, Pasquale; Nohrden, Doerte; Assmann, Sabine; Schmitt, Roland; Grandi, Marco

    2009-01-10

    The issue of juvenile pornography has seen an increase in the past few years of the number of expert opinions requested to forensic pathologists, paediatricians and other various experts within the forensic and medical fields concerning the age of represented individuals. Regardless of the entity of the problem, no actual method exists which can allow us to give an objective and scientific answer, particularly in the postpubertal stage. Using parameters related to sexual maturation can be very dangerous. Nonetheless some experts still insist with similar types of "expertises". This study aims at verifying the ability of different experts in assessing age of postpubertal individuals represented in pornographic material. Results underline the difficulties and major uncertainties of age evaluation by visual observation of photographic material particularly when the subjects have reached the sexual maturation stage - and therefore in verifying whether the individual is above or below 18 years of age (an important age limit for most European countries as far as this type of crime is concerned). Furthermore the study stresses the need both to search for an alternate approach and to apply extreme caution in judicial evaluation. PMID:19019589

  10. Characterization of Finnish Building materials under salt frost artificial ageing

    NASA Astrophysics Data System (ADS)

    Luodes, Nike M.; Torppa, Akseli; Pirinen, Heikki; Bellopede, Rossana; Marini, Paola

    2016-04-01

    Under a national project co financed by the Confederation of Finnish Construction Industries RT (CFCI), the Finnish Natural Stone Association and the Geological Survey of Finland (GTK), and thanks to the cooperation with the Polytechnic of Turin a comprehensive number of Finnish natural stones has been tested according to SFS EN standards for national CE marking and according to non standardized methods for research purposes. The aim was to evaluate the effects of combined salt and frost weathering caused by de-icing salts and to research a possible correlation between laboratory's accelerated decay and site weathering. The materials tested (60 stones in total) are mainly silicate rocks showing good resistance to the weathering. Results have been affected in some cases by uncertainties connected to the variation of material quality. Some materials have been from new quarries and variation of their properties has been higher than the effects of artificial weathering. Material sampled from crop presented higher weathering level and the additional artificial weathering has induced small variations. Results have shown that material weathering has been better represented by variation of flexural strength compared to uniaxial compressive strength. The most probable reason has been that small changes of planarity and perpendicularity had greater effects on the compressive strength than variations by weathering. Fifteen representative typologies of natural stones have been tested with non standardized methodologies to study the changes of the material and finding a possible correlation with methods used on site. Schmidt rebound test and Ultra Pulse Velocity (UPV) have been used on site to assess the durability of stone on construction. Materials tested in laboratory have shown less variation between rebounds compared to site tests, this can be because of a more controlled environment and saw cut surface instead of rocky or chiselled ones. Laboratory tests showed an average

  11. Evaluation Of Potting Materials For Use In Extreme Cold

    NASA Technical Reports Server (NTRS)

    Acosta, Ernesto

    1992-01-01

    Tests help identify noncracking combinations of materials. Aid evaluation of potting materials for copper coils used at low temperatures to measure magnetic fields. Also determine effects of distribution of microballoons, voids, and porosity. Materials also evaluated for ease of use.

  12. Aging evaluation of class 1E batteries: Seismic testing

    SciTech Connect

    Edson, J.L. )

    1990-08-01

    This report presents the results of a seismic testing program on naturally aged class 1E batteries obtained from a nuclear plant. The testing program is a Phase 2 activity resulting from a Phase 1 aging evaluation of class 1E batteries in safety systems of nuclear power plants, performed previously as a part of the US Nuclear Regulatory Commission's Nuclear Plant Aging Research Program and reported in NUREG/CR-4457. The primary purpose of the program was to evaluate the seismic ruggedness of naturally aged batteries to determine if aged batteries could have adequate electrical capacity, as determined by tests recommended by IEEE Standards, and yet have inadequate seismic ruggedness to provide needed electrical power during and after a safe shutdown earthquake (SSE) event. A secondary purpose of the program was to evaluate selected advanced surveillance methods to determine if they were likely to be more sensitive to the aging degradation that reduces seismic ruggedness. The program used twelve batteries naturally aged to about 14 years of age in a nuclear facility and tested them at four different seismic levels representative of the levels of possible earthquakes specified for nuclear plants in the United States. Seismic testing of the batteries did not cause any loss of electrical capacity. 19 refs., 29 figs., 7 tabs.

  13. Evaluation of a Community-Based Aging Intervention Program

    ERIC Educational Resources Information Center

    Hsu, Hui-Chuan; Wang, Chun-Hou; Chen, Yi-Chun; Chang, Ming-Chen; Wang, Jean

    2010-01-01

    This study evaluated the outcome and process of a community-based aging intervention program for the elderly in Taiwan. The program included education on nutrition and dietary behavior and on physical activities. Outcome and process evaluations were conducted. The program may have had some effects on decreasing some dietary behavioral problems and…

  14. Evaluation of nonaqueous processes for nuclear materials

    SciTech Connect

    Musgrave, B.C.; Grens, J.Z.; Knighton, J.B.; Coops, M.S.

    1983-12-01

    A working group was assigned the task of evaluating the status of nonaqueous processes for nuclear materials and the prospects for successful deployment of these technologies in the future. In the initial evaluation, the study was narrowed to the pyrochemical/pyrometallurgical processes closely related to the processes used for purification of plutonium and its conversion to metal. The status of the chemistry and process hardware were reviewed and the development needs in both chemistry and process equipment technology were evaluated. Finally, the requirements were established for successful deployment of this technology. The status of the technology was evaluated along three lines: (1) first the current applications were examined for completeness, (2) an attempt was made to construct closed-cycle flow sheets for several proposed applications, (3) and finally the status of technical development and future development needs for general applications were reviewed. By using these three evaluations, three different perspectives were constructed that together present a clear picture of how complete the technical development of these processes are.

  15. Colour measurements of surfaces to evaluate the restoration materials

    NASA Astrophysics Data System (ADS)

    Lo Monaco, Angela; Marabelli, Maurizio; Pelosi, Claudia; Picchio, Rodolfo

    2011-06-01

    In this paper two case studies on the application of colour measurements for the evaluation of some restoration materials are discussed. The materials related to the research are: watercolours employed in restoration of wall paintings and preservative/consolidants for wood artifacts. Commercial watercolours, supplied by Maimeri, Windsor&Newton and Talens factories have been tested. Colour measurements have been performed by means of a reflectance spectrophotometer (RS) before and after accelerated ageing of watercolours at 92% relative humidity (RH) and in a Solar Box chamber. The experimental results show that watercolours based on natural earths and artificial ultramarine undergo the main colour changes, expressed as L*, a* and b* variations and total colour difference (▵E*). In the other cases colour differences depend on both watercolour typology and suppliers. The other example concerns the evaluation of colour change due to surface treatment of Poplar (Populus sp.) and chestnut (Castanea sativa L.) wood samples. The wooden samples have been treated with a novel organic preservative/consolidant product that has been tested also in a real case as comparison. The treated samples have been artificially aged in Solar Box chamber equipped with a 280 nm UV filter. Colour has been measured before and after the artificial ageing by means of a RS. Colour changes have been determined also for the main door of an historical mansion in Viterbo, made of chestnut wood, and exposed outdoors.

  16. Commercial off-the-Shelf (COTS) Refractory Material Evaluation

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Kolody, Mark R.; Curran, Jerome P.; Back, Teddy; Hintze, Paul E.; Parlier, Christopher R.; Sampson, Jeffrey W.; Perusich, Stephen; Bucherl, Cori

    2009-01-01

    Fondu Fyre (FF) is currently the only refractory material qualified for use in the flame trench at KSC's Shuttle Launch Pads 39A and 39B. However, the material is not used as it was qualified and has undergone increasingly frequent and severe degradation due to the launch blasts. This degradation is costly as well as dangerous for launch infrastructure, crew and vehicle. FF is applied at the pad via the gunnite process, where wetted refractory material is sprayed onto a steel grid mounted on a support structure. The water content in this process can be manually adjusted by operators, causing distinct visual and physical discrepancies among repair areas. Since the application process is unlikely to change for new refractory materials, it is important to understand the effects of water content on commercial off-the-shelf (COTS) refractory materials. The purpose of this study was to evaluate the performance of the FF with respect to various water contents as well as heat treatments, to simulate aging and exposure to the blast. Initial results indicated that different water contents and heat treatments result in distinct differences in crushing strength, apparent porosity and bulk density. However, water content became an insignificant factor in both crush strength and porosity when FF was cured to at least 1500 deg. Additionally, inspection of the material's surface microstructure by scanning electron microscopy indicated distinguishable characteristics for different heat treatment levels. Results from this study will help guide future studies on the development and identification of new refractory materials.

  17. Thermography evaluation of metal bonding materials

    NASA Astrophysics Data System (ADS)

    Safai, Morteza

    The thermographic technique used for the nondestructive evaluation of bondline integrity in metal and silicone rubber bonded material is described. An AGEMA model 880 IR thermographic scanner combined with a 20-deg lens was used to detect the IR radiation from the test panel. A video tape recorder was used to record the live temperature distribution at 25 picture frames per second. A personal computer with an AGEMA TIC-8000 digital image processor was used to record and plot the temperature vs time. The technique was found to be capable of detecting subsurface disbonds as small as 0.0625 sq in. in 0.187-in.-thick thermal protection system bonded materials. The thermography technique meets all the requirements of other approved NDT techniques, and it works well with complex structures and is noncontaminating, noncontact, real-time, and portable.

  18. Thermography evaluation of metal bonding materials

    NASA Astrophysics Data System (ADS)

    Safai, Morteza

    1992-04-01

    The thermographic technique used for the nondestructive evaluation of bondline integrity in metal and silicone rubber bonded material is described. An AGEMA model 880 IR thermographic scanner combined with a 20-deg lens was used to detect the IR radiation from the test panel. A video tape recorder was used to record the live temperature distribution at 25 picture frames per second. A personal computer with an AGEMA TIC-8000 digital image processor was used to record and plot the temperature vs time. The technique was found to be capable of detecting subsurface disbonds as small as 0.0625 sq in. in 0.187-in.-thick thermal protection system bonded materials. The thermography technique meets all the requirements of other approved NDT techniques, and it works well with complex structures and is noncontaminating, noncontact, real-time, and portable.

  19. Evaluation of powder metallurgy superalloy disk materials

    NASA Technical Reports Server (NTRS)

    Evans, D. J.

    1975-01-01

    A program was conducted to develop nickel-base superalloy disk material using prealloyed powder metallurgy techniques. The program included fabrication of test specimens and subscale turbine disks from four different prealloyed powders (NASA-TRW-VIA, AF2-1DA, Mar-M-432 and MERL 80). Based on evaluation of these specimens and disks, two alloys (AF2-1DA and Mar-M-432) were selected for scale-up evaluation. Using fabricating experience gained in the subscale turbine disk effort, test specimens and full scale turbine disks were formed from the selected alloys. These specimens and disks were then subjected to a rigorous test program to evaluate their physical properties and determine their suitability for use in advanced performance turbine engines. A major objective of the program was to develop processes which would yield alloy properties that would be repeatable in producing jet engine disks from the same powder metallurgy alloys. The feasibility of manufacturing full scale gas turbine engine disks by thermomechanical processing of pre-alloyed metal powders was demonstrated. AF2-1DA was shown to possess tensile and creep-rupture properties in excess of those of Astroloy, one of the highest temperature capability disk alloys now in production. It was determined that metallographic evaluation after post-HIP elevated temperature exposure should be used to verify the effectiveness of consolidation of hot isostatically pressed billets.

  20. The Effects of Aging on Clinical Vestibular Evaluations

    PubMed Central

    Maheu, Maxime; Houde, Marie-Soleil; Landry, Simon P.; Champoux, François

    2015-01-01

    Balance disorders are common issues for aging populations due to the effects of normal aging on peripheral vestibular structures. These changes affect the results of vestibular function evaluations and make the interpretation of these results more difficult. The objective of this article is to review the current state of knowledge of clinically relevant vestibular measures. We will first focus on otolith function assessment methods cervical-VEMP (cVEMP) and ocular-VEMP (oVEMP), then the caloric and video-head impulse test (vHIT) methods for semicircular canals assessment. cVEMP and oVEMP are useful methods, though research on the effects of age for some parameters are still inconclusive. vHIT results are largely independent of age as compared to caloric stimulation and should therefore be preferred for the evaluation of the semicircular canals function. PMID:26441824

  1. Performance testing of aged hydrogen getters against criteria for interim safe storage of plutonium bearing materials.

    SciTech Connect

    Shepodd, Timothy J.; Nissen, April; Buffleben, George M.

    2006-01-01

    Hydrogen getters were tested for use in storage of plutonium-bearing materials in accordance with DOE's Criteria for Interim Safe Storage of Plutonium Bearing Materials. The hydrogen getter HITOP was aged for 3 months at 70 C and tested under both recombination and hydrogenation conditions at 20 and 70 C; partially saturated and irradiated aged getter samples were also tested. The recombination reaction was found to be very fast and well above the required rate of 45 std. cc H2h. The gettering reaction, which is planned as the backup reaction in this deployment, is slower and may not meet the requirements alone. Pressure drop measurements and {sup 1}H NMR analyses support these conclusions. Although the experimental conditions do not exactly replicate the deployment conditions, the results of our conservative experiments are clear: the aged getter shows sufficient reactivity to maintain hydrogen concentrations below the flammability limit, between the minimum and maximum deployment temperatures, for three months. The flammability risk is further reduced by the removal of oxygen through the recombination reaction. Neither radiation exposure nor thermal aging sufficiently degrades the getter to be a concern. Future testing to evaluate performance for longer aging periods is in progress.

  2. Survey and evaluation of aging risk assessment methods and applications

    SciTech Connect

    Sanzo, D.L.; Kvam, P.; Apostolakis, G.; Wu, J.; Milici, T.; Ghoniem, N.; Guarro, S.

    1993-11-01

    The Nuclear Regulatory Commission (NRC) initiated the nuclear power plant aging research (NPAR) program about 6 years ago to gather information about nuclear power plant aging. Since then, this program has collected a significant amount of information, largely qualitative, on plant aging and its potential effects on plant safety. However, this body of knowledge has not yet been integrated into formalisms that can be used effectively and systematically to assess plant risk resulting from aging, although models for assessing the effect of increasing failure rates on core damage frequency have been proposed. The purpose of this review is to survey the work conducted to address the aging of systems, structures, and components (SSCs) of nuclear power plants (NPPs), as well as the associated data bases. The review takes a critical look at the need to revise probabilistic risk assessment (PRAs) so that they will include the contribution to risk from plant aging, the adequacy of existing methods for evaluating this contribution, and the adequacy of the data that have been used in these evaluation methods. A preliminary framework is identified for integrating the aging of SSCs into the PRA, including the identification of needed data for such an integration.

  3. Evaluation of Instructional Materials. Position Paper No. 1.

    ERIC Educational Resources Information Center

    Ward, Ted

    The position paper on the evaluation of instructional materials by the Michigan State University Regional Instructional Materials Center for Handicapped Children and Youth (IMC HCY) examines the professional and ethical dilemmas of evaluation and presents evaluation policies of the center. Evaluated by a roster of field evaluators throughout the…

  4. Synthesis and evaluation of energetic materials

    NASA Astrophysics Data System (ADS)

    Santhosh, G.

    Over the years new generations of propellants and explosives are being developed. High performance and pollution prevention issues have become the subject of interest in recent years. Desired properties of these materials are a halogen-free, nitrogen and oxygen rich molecular composition with high density and a positive heat of formation. The dinitramide anion is a new oxy anion of nitrogen and forms salts with variety of metal, organic and inorganic cations. Particular interest is in ammonium dinitramide (ADN, NH4N(NO 2)2) which is a potentially useful energetic oxidizer. ADN is considered as one of the most promising substitutes for ammonium perchlorate (AP, NH4ClO4) in currently used composite propellants. It is unique among energetic materials in that it has no carbon or chlorine; its combustion products are not detrimental to the atmosphere. Unquestionable advantage of ADN over AP is the significant improvement in the performance of solid rocket motors by 5-15%. The present thesis is centered on the experimental results along with discussion of some of the most pertinent aspects related to the synthesis and characterization of few dinitramide salts. The chemistry, mechanism and kinetics of the formation of dinitramide salts by nitration of deactivated amines are investigated. The evaluation of the thermal and spectral properties along with the adsorption and thermal decomposition characteristics of the dinitramide salts are also explored in this thesis.

  5. Materials evaluation for a transuranic processing facility

    SciTech Connect

    Barker, S.A., Schwenk, E.B. ); Divine, J.R. )

    1990-11-01

    The Westinghouse Hanford Company, with the assistance of the Pacific Northwest Laboratory, is developing a transuranium extraction process for preheating double-shell tank wastes at the Hanford Site to reduce the volume of transuranic waste being sent to a repository. The bench- scale transuranium extraction process development is reaching a stage where a pilot plant design has begun for the construction of a facility in the existing B Plant. Because of the potential corrosivity of neutralized cladding removal waste process streams, existing embedded piping alloys in B Plant are being evaluated and new'' alloys are being selected for the full-scale plant screening corrosion tests. Once the waste is acidified with HNO{sub 3}, some of the process streams that are high in F{sup {minus}} and low in Al and zr can produce corrosion rates exceeding 30,000 mil/yr in austenitic alloys. Initial results results are reported concerning the applicability of existing plant materials to withstand expected process solutions and conditions to help determine the feasibility of locating the plant at the selected facility. In addition, process changes are presented that should make the process solutions less corrosive to the existing materials. Experimental work confirms that Hastelloy B is unsatisfactory for the expected process solutions; type 304L, 347 and 309S stainless steels are satisfactory for service at room temperature and 60{degrees}C, if process stream complexing is performed. Inconel 625 was satisfactory for all solutions. 17 refs., 5 figs., 8 tabs.

  6. Evaluation of NRC maintenance team inspection reports for managing aging

    SciTech Connect

    Fresco, A.; Gunther, W.

    1991-01-01

    A nuclear power plant's maintenance program is the principal vehicle through which age-related degradation is managed. Over the past two years, the NRC (Nuclear Regulatory Commission) has evaluated the maintenance program of every nuclear power plant in the U.S. The reports issued on these in-depth team inspections have been reviewed to ascertain the strengths and weaknesses of the programs as related to the need to understand and manage the effects of aging on nuclear power plant systems, structures, and components. Selected results of this review are presented in this paper, including examples of inspection and monitoring techniques successfully used by utilities to detect degradation due to aging. Attributes of plant maintenance programs where the NRC inspectors felt that improvement was needed to properly address the aging issue are also discussed. 6 refs., 1 tab.

  7. Effect of aging on tear strength and cytotoxicity of soft denture lining materials; in vitro

    PubMed Central

    Landayan, Jordi Izzard Andaya; Manaloto, Adrian Carlos Francisco; Shin, Sang-Wan

    2014-01-01

    PURPOSE The aim of this in vitro study was to evaluate the effect of aging on the tear strength and cytotoxicity of four soft denture lining materials. MATERIALS AND METHODS Four commonly used soft denture lining materials, (Coe-Comfort™ GC America Inc., Alsip, IL, USA; Coe-Soft™ GC America Inc., Alsip, IL, USA; Visco-gel Dentsply Caulk Milford, DE, USA; and Sofreliner Tough M Tokuyama Dental Corporation Tokyo, Japan) were selected. Sixty trouser-leg designed specimens per lining material were fabricated using a stainless steel mold for tear strength testing. The specimens were divided into non-thermocycling and 1000-, and 3000- thermocycling groups. For the cytotoxicity test, twenty-four disk shaped specimens per material were fabricated using a stainless steel mold. The specimens were soaked in normal saline solution for 24 h, 48 h and 72 h. Cytotoxicity was measured by XTT assay in L929 mouse fibroblasts. Data were analyzed by two way analysis of variance and Dunnett's test (P<.05). RESULTS Before thermocycling, Sofreliner Tough M (10.36 ± 1.00 N) had the highest tear strength value while Coe-Comfort™ (0.46 ± 0.10 N) had the lowest. After 3000 cycles, Sofreliner Tough M (9.65 ± 1.66 N) presented the highest value and Coe-Comfort™ (0.42 ± 0.08 N) the lowest. Sofreliner Tough M, in all incubation periods was the least toxic with significant differences compared to all other materials (P<.05). Coe-Comfort™, Coe-Soft™, and Sofreliner Tough M did not show any significant differences within their material group for all incubation periods. CONCLUSION This in vitro study revealed that aging can affect both the tear strength and cytotoxicity of soft denture materials depending on the composition. PMID:24843396

  8. 46 CFR 30.30-3 - Evaluation materials.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Evaluation materials. 30.30-3 Section 30.30-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Interim Procedures for Evaluating Vessel Personnel Licensing and Certification Programs of Foreign Countries § 30.30-3 Evaluation materials. The materials to be submitted...

  9. 46 CFR 30.30-3 - Evaluation materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Evaluation materials. 30.30-3 Section 30.30-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Interim Procedures for Evaluating Vessel Personnel Licensing and Certification Programs of Foreign Countries § 30.30-3 Evaluation materials. The materials to be submitted...

  10. 46 CFR 30.30-3 - Evaluation materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Evaluation materials. 30.30-3 Section 30.30-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Interim Procedures for Evaluating Vessel Personnel Licensing and Certification Programs of Foreign Countries § 30.30-3 Evaluation materials. The materials to be submitted...

  11. 46 CFR 30.30-3 - Evaluation materials.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Evaluation materials. 30.30-3 Section 30.30-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Interim Procedures for Evaluating Vessel Personnel Licensing and Certification Programs of Foreign Countries § 30.30-3 Evaluation materials. The materials to be submitted...

  12. 46 CFR 30.30-5 - Submission of evaluation materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Submission of evaluation materials. 30.30-5 Section 30.30-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Interim...-5 Submission of evaluation materials. (a) The evaluation materials listed in § 30.30-3 should...

  13. 46 CFR 30.30-5 - Submission of evaluation materials.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Submission of evaluation materials. 30.30-5 Section 30.30-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Interim...-5 Submission of evaluation materials. (a) The evaluation materials listed in § 30.30-3 should...

  14. 46 CFR 30.30-5 - Submission of evaluation materials.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Submission of evaluation materials. 30.30-5 Section 30.30-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Interim...-5 Submission of evaluation materials. (a) The evaluation materials listed in § 30.30-3 should...

  15. METHODOLOGY FOR EXAMINING SYSTEM AGING DUE TO INTERACTIONS BETWEEN CHEMICALLY INCOMPATIBLE MATERIALS

    SciTech Connect

    J. DENINGER; J. TANSKI

    1999-04-01

    We start with a stored and unused population of fielded engineered units that are composed of chemically incompatible materials. The units age primarily through heterogeneous chemical reactions between the materials resulting in possible degradation in performance. The engineered units are unused in storage, but may be called into actual service at any time. We sample several units from the population per year and perform a number of non-destructive evaluation (NDE) techniques, such as radiography, low-frequency vibration analysis, and ultrasonic imaging on the selected units. From those units, some are selected for destructive testing (D-test) involving disassembly and testing of internal parts and components. Chemical analyses, mechanical properties measurements and other tests are performed. All of the above steps provide information that is used in the system simulation mathematical model. The system simulation model incorporates chemical reactions and gas-solid transport processes, along with changes in both the surface and bulk properties of the solids. Model results are used to suggest improvements in NDE analyses of the units and improvements in component and material analyses. Model results give trending indications of individual component and overall system changes over time, plus some understanding of the mechanisms involved which allow science-based predictions of the aged state of the units in future times. The NDE, D-test, and model results can also be used to assess statistically the reliability and performance of the overall aging population of units.

  16. A Research Project to Develop and Evaluate a Technical Education Component on Materials Technology for Orientation to Space-Age Technology, Covering the Period July 1, 1974 - January 31, 1976. Final Technical Report.

    ERIC Educational Resources Information Center

    Jacobs, James A.

    This developmental applied research project aims to provide an effective means of orienting non-traditional students, especially minorities and females, to engineering technology, and particularly to basic materials science. The instructional system adopted involves self-paced, individualized instruction, breaking the technical education component…

  17. Working with Aging and Aged Developmentally Disabled Persons: Training Materials for Caregivers. Instructor's Manual, Volume I.

    ERIC Educational Resources Information Center

    Dickerson, Martha Ufford; Thurman, Eunice M.

    This instructor's manual, developed to assist the training instructor of a program entitled "The Aging and Aged Developmentally Disabled," provides information to enhance the skills of inservice and preservice caregivers and other professionals who work with the aging developmentally disabled. The objectives of the two training units,…

  18. Evaluation of aging of cast stainless steel components

    SciTech Connect

    Chung, H.M.

    1991-02-01

    Cast stainless steel is used extensively in nuclear reactors for primary-pressure-boundary components such as primary coolant pipes, elbows, valves, pumps, and safe ends. These components are, however, susceptible to thermal aging embrittlement in light water reactors because of the segregation of Cr atoms from Fe and Ni by spinodal decomposition in ferrite and the precipitation of Cr-rich carbides on ferrite/austenite boundaries. A recent advance in understanding the aging kinetics is presented. Aging kinetics are strongly influenced by the synergistic effects of other metallurgical reactions that occur in parallel with spinodal decomposition, i.e., clustering of Ni, Mo, and Si solute atoms and the nucleation and growth of G-phase precipitates in the ferrite phase. A number of methods are outlined for estimating aging embrittlement under end-of-life of life-extension conditions, depending on several factors such as degree of permissible conservatism, availability of component archive material, and methods of estimating and verifying the activation energy of aging. 33 refs., 6 figs., 3 tabs.

  19. Effect of shelf aging on O-ring materials

    NASA Technical Reports Server (NTRS)

    Wood, T. E.; Stone, W. P.

    1978-01-01

    Commercial O-rings made from 13 different rubber compounds were tested for physical properties after 7 and 12 years of shelf aging. No gross changes were observed in tensile strength, elongation, or compression deflection characteristics.

  20. Evaluation of Obesity in School-Age Children.

    PubMed

    Dobashi, Kazushige

    2016-01-01

    To prevent obesity in middle age, early precautions and interventions are required during childhood. Therefore, it is very important to accurately evaluate the degree of overweight in children. Body mass index (BMI) is widely used worldwide in adults, but not in children. Because standard BMI, which is calculated using the average height and weight for age, changes widely during growth, a constant cut-off point cannot be set for children. An international unified method defining childhood obesity has not been established. In many countries, BMI-for-age percentile (BMI%) value or Z (standard deviation) score is used, whereas in Japan, the percentage of overweight (POW), which is the modified weight-for-height method, is used. We compared BMI% values with POW values obtained using the anthropometric data of elementary and junior high school students based on the Japanese school survey conducted in 2000 and found that the values for the degree of overweight were significantly different between the two methods. It became clear that tall students were easily defined as being overweight, whereas short students tended to be evaluated as being underweight when using BMI%. POW method seemed to be more appropriate than BMI% for school-age children. Abdominal obesity, excess visceral adipose tissue (VAT), is highly associated with obesity-related complications. Waist circumference (WC) is now accepted as an appropriate guide to VAT accumulation. The cut-off value of WC defining excess VAT is 80 cm at the umbilical level in Japanese school-age children. It is not easy to decide the obesity criteria and optimum WC in school-age children. Childhood obesity should be discussed more internationally. PMID:26510873

  1. [Expert evaluation by forensic psychiatrists of aged delinquents].

    PubMed

    Lemańczyk, W; Kordacka, M

    1989-01-01

    In the period from 1970 till 1987 forensic psychiatric certification of 1333 delinquents war made in Regional Psychiatric Hospital in Cibórz. Forty experts (3%) regarded subjects aged 60 years or more. The most common crimes were those against life and health--62.5%; predominantly homicides, assaults and assaults on public functioning, as well as arson--10%. Among male delinquents 68% were under the influence of alcohol at the time of crime of arson and assaults. Other common crime were establish in 15%. Only 1 patient was accused of sexual child abuse (2.5%). Women made 20% of offenders; one half of them committed the crime against life and health, mainly menace. Mental disturbances were found in 90% of patients. Dementia was diagnosed in 20%, organic personality disorder in 30%, and pseudoneurotic syndrome in 15%. Delusional syndrome was diagnosed in 15% while 5% of patients had long history of psychiatric disorders. 35% of expertise were made during single psychiatric interview. It is our opinion that a single examination of aged delinquent does not allow the correct evaluation of the influence of complex relations between possible mental disturbances, somatic illness, drugs (often various pathology and polytherapy) and alcohol, on delinquent's soundness of mind. Taking into consideration the widespread of above mentioned disturbances in the aged population we think that every person in the age above 60 suspected of crime should undergo psychiatric evaluation and hospital observation. PMID:2631130

  2. 46 CFR 30.30-3 - Evaluation materials.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Evaluation materials. 30.30-3 Section 30.30-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Interim Procedures for... materials. The materials to be submitted for evaluation must include the English text of the following:...

  3. LEVERAGING AGING MATERIALS DATA TO SUPPORT EXTENSION OF TRANSPORTATION SHIPPING PACKAGES SERVICE LIFE

    SciTech Connect

    Dunn, K.; Bellamy, S.; Daugherty, W.; Sindelar, R.; Skidmore, E.

    2013-08-18

    Nuclear material inventories are increasingly being transferred to interim storage locations where they may reside for extended periods of time. Use of a shipping package to store nuclear materials after the transfer has become more common for a variety of reasons. Shipping packages are robust and have a qualified pedigree for performance in normal operation and accident conditions but are only certified over an approved transportation window. The continued use of shipping packages to contain nuclear material during interim storage will result in reduced overall costs and reduced exposure to workers. However, the shipping package materials of construction must maintain integrity as specified by the safety basis of the storage facility throughout the storage period, which is typically well beyond the certified transportation window. In many ways, the certification processes required for interim storage of nuclear materials in shipping packages is similar to life extension programs required for dry cask storage systems for commercial nuclear fuels. The storage of spent nuclear fuel in dry cask storage systems is federally-regulated, and over 1500 individual dry casks have been in successful service up to 20 years in the US. The uncertainty in final disposition will likely require extended storage of this fuel well beyond initial license periods and perhaps multiple re-licenses may be needed. Thus, both the shipping packages and the dry cask storage systems require materials integrity assessments and assurance of continued satisfactory materials performance over times not considered in the original evaluation processes. Test programs for the shipping packages have been established to obtain aging data on materials of construction to demonstrate continued system integrity. The collective data may be coupled with similar data for the dry cask storage systems and used to support extending the service life of shipping packages in both transportation and storage.

  4. Mechanical evaluation of a soft cast material.

    PubMed

    Zmurko, M G; Belkoff, S M; Herzenberg, J E

    1997-08-01

    In this study, the structural and material properties of a new semi-rigid material, Scotchcast SoftCast (SCS), were compared to the properties of two rigid materials, plaster of paris (POP) and Scotchcast Plus (SCP). Cylinders and flat beams made from 4, 6, 8, and 10 layers of each casting material were tested in three-point bending and diametrical compression. Initial stiffness and yield force values of SCS casts were significantly lower than for casts of SCP and POP made of the same number of layers. Casts made from SCS may be indicated for non-rigid applications, but not where rigid immobilization is required. PMID:9263288

  5. Non-Destructive Evaluation of Materials via Ultraviolet Spectroscopy

    NASA Technical Reports Server (NTRS)

    Pugel, Betsy

    2008-01-01

    A document discusses the use of ultraviolet spectroscopy and imaging for the non-destructive evaluation of the degree of cure, aging, and other properties of resin-based composite materials. This method can be used in air, and is portable for field use. This method operates in reflectance, absorbance, and luminescence modes. The ultraviolet source is used to illuminate a composite surface of interest. In reflectance mode, the reflected response is acquired via the imaging system or via the spectrometer. The spectra are analyzed for organic compounds (conjugated organics) and inorganic compounds (semiconducting band-edge states; luminescing defect states such as silicates, used as adhesives for composite aerospace applications; and metal oxides commonly used as thermal coating paints on a wide range of spacecraft). The spectra are compared with a database for variation in conjugation, substitution, or length of molecule (in the case of organics) or band edge position (in the case of inorganics). This approach is useful in the understanding of material quality. It lacks the precision in defining the exact chemical structure that is found in other materials analysis techniques, but it is advantageous over methods such as nuclear magnetic resonance, infrared spectroscopy, and chromatography in that it can be used in the field to assess significant changes in chemical structure that may be linked to concerns associated with weaknesses or variations in structural integrity, without disassembly of or destruction to the structure of interest.

  6. Assessment of Cable Aging Equipment, Status of Acquired Materials, and Experimental Matrix at the Pacific Northwest National Laboratory

    SciTech Connect

    Fifield, Leonard S.; Westman, Matthew P.; Zwoster, Andy; Schwenzer, Birgit

    2015-03-30

    The need for increased understanding of the aging and degradation behavior for polymer components of nuclear power plant electrical cables is described in this report. The highest priority materials for study and the resources available at PNNL for these studies are also described. The anticipated outcomes of the PNNL work described are : improved understanding of appropriate accelerated aging conditions, improved knowledge of correlation between observable aging indicators and cable condition in support of advanced non-destructive evaluation methods, and practical knowledge of condition-based cable lifetime prediction.

  7. Aging Management Using Proactive Management of Materials Degradation

    NASA Astrophysics Data System (ADS)

    Doctor, S. R.; Bond, L. J.; Cumblidge, S. E.; Bruemmer, S. M.; Taylor, W. B.; Carpenter, C. E.; Hull, A. B.; Malik, S. N.

    2010-02-01

    The U.S. Nuclear Regulatory Commission (NRC) has undertaken a program to lay the technical foundations for defining proactive actions to manage degradation of materials in light water reactors. The current focus is existing plants; however, if applied to new construction, there is potential to better monitor and manage plants throughout their life cycle. This paper discusses the NRC's Proactive Management of Materials Degradation program and its application to nuclear power plant structures, systems, and components.

  8. AGING MANAGEMENT USING PROACTIVE MANAGEMENT OF MATERIALS DEGRADATION

    SciTech Connect

    Doctor, S. R.; Bond, L. J.; Cumblidge, S. E.; Bruemmer, S. M.; Taylor, W. B.; Carpenter, C. E.; Hull, A. B.; Malik, S. N.

    2010-02-22

    The U.S. Nuclear Regulatory Commission (NRC) has undertaken a program to lay the technical foundations for defining proactive actions to manage degradation of materials in light water reactors. The current focus is existing plants; however, if applied to new construction, there is potential to better monitor and manage plants throughout their life cycle. This paper discusses the NRC's Proactive Management of Materials Degradation program and its application to nuclear power plant structures, systems, and components.

  9. Aging Management using Proactive Management of Materials Degradation

    SciTech Connect

    Doctor, Steven R.; Bond, Leonard J.; Cumblidge, Stephen E.; Bruemmer, Stephen M.; Taylor, W Boyd; Carpenter, C. E.; Hull, Amy B.; Malik, Shah

    2010-10-01

    The U.S. Nuclear Regulatory Commission (NRC) has undertaken a program to lay the technical foundations for defining proactive actions to manage degradation of materials in light water reactors (LWRs). The current focus is existing plants; however, if applied to new construction, there is potential to better monitor and manage plants throughout their life cycle. This paper discusses the NRC’s Proactive Management of Materials Degradation (PMMD) program and its application to nuclear power plant structures, systems, and components (SSC).

  10. Aging rat vestibular ganglion: I. Quantitative light microscopic evaluation.

    PubMed

    Alidina, A; Lyon, M J

    1990-01-01

    This study was undertaken to quantify age-related changes in the rat vestibular ganglion. Cell number, diameter, and proximal-distal distribution based on size were evaluated. Serial 5-microns plastic sections of the vestibular ganglion from 15 female Wistar rats were examined. Rats were divided into three age groups: young (Y, 3 to 5 months, n = 5), old (0, 24 to 26 months, n = 3), and very old (VO, 28 to 31 months, n = 7). Quantitative analysis indicated no significant differences (P less than .05) in the estimated number of ganglion cells (mean: Y = 1,690, 0 = 2,257, VO = 1,678), ganglion cell profile diameters (mean: Y = 22.5 microns, n = 2,886; O = 23.7 microns, n = 2,313; VO = 22.8 microns, n = 4,061), or proximal-distal localization (proximal: 22.3 microns, 24.4 microns, 22.7 microns; middle: 22.6 microns, 23.1 microns, 22.4 microns; distal: 23.3 microns, 23.4 microns, 23.7 microns; Y, O, and VO, respectively). When pooled, the old animals tended to have slightly larger cell profiles than the other groups. We noted a dramatic age-related increase of aging pigment within the ganglion cell profiles, making the old and very old animals easily distinguishable from the young. In most of the cell profiles, the aging pigment was more or less uniformly distributed throughout the cytoplasm. However, in some, aging pigment was accumulated at one pole of the cell profile. While no typical degenerating cellular profiles were found in any of the sections, several of the ganglion cell profiles from the old animals revealed dense cytoplasm, possibly indicating an early stage of degeneration. PMID:2382785

  11. Evaluations of mosquito age grading techniques based on morphological changes.

    PubMed

    Hugo, L E; Quick-Miles, S; Kay, B H; Ryan, P A

    2008-05-01

    Evaluations were made of the accuracy and practicality of mosquito age grading methods based on changes to mosquito morphology; including the Detinova ovarian tracheation, midgut meconium, Polovodova ovariole dilatation, ovarian injection, and daily growth line methods. Laboratory maintained Aedes vigilax (Skuse) and Culex annulirostris (Skuse) females of known chronological and physiological ages were used for these assessments. Application of the Detinova technique to laboratory reared Ae. vigilax females in a blinded trial enabled the successful identification of nulliparous and parous females in 83.7-89.8% of specimens. The success rate for identifying nulliparous females increased to 87.8-98.0% when observations of ovarian tracheation were combined with observations of the presence of midgut meconium. However, application of the Polovodova method only enabled 57.5% of nulliparous, 1-parous, 2-parous, and 3-parous Ae. vigilax females to be correctly classified, and ovarian injections were found to be unfeasible. Poor correlation was observed between the number of growth lines per phragma and the calendar age of laboratory reared Ae. vigilax females. In summary, morphological age grading methods that offer simple two-category predictions (ovarian tracheation and midgut meconium methods) were found to provide high-accuracy classifications, whereas methods that offer the separation of multiple age categories (ovariolar dilatation and growth line methods) were found to be extremely difficult and of low accuracy. The usefulness of the morphology-based methods is discussed in view of the availability of new mosquito age grading techniques based on cuticular hydrocarbon and gene transcription changes. PMID:18533427

  12. Explosive materials equivalency, test methods and evaluation

    NASA Technical Reports Server (NTRS)

    Koger, D. M.; Mcintyre, F. L.

    1980-01-01

    Attention is given to concepts of explosive equivalency of energetic materials based on specific airblast parameters. A description is provided of a wide bandwidth high accuracy instrumentation system which has been used extensively in obtaining pressure time profiles of energetic materials. The object of the considered test method is to determine the maximum output from the detonation of explosive materials in terms of airblast overpressure and positive impulse. The measured pressure and impulse values are compared with known characteristics of hemispherical TNT data to determine the equivalency of the test material in relation to TNT. An investigation shows that meaningful comparisons between various explosives and a standard reference material such as TNT should be based upon the same parameters. The tests should be conducted under the same conditions.

  13. An Evaluation of the Oxygen Compatibility of Composite Materials

    NASA Technical Reports Server (NTRS)

    Richardson, Erin H.; Hall, Joylene

    2003-01-01

    Three tests are described which evaluate the oxygen compatibility characteristics of multiple composite materials: 1) Mechanical Impact Bruceton 'Up and Down' Method; 2) Promoted Combustion; 3) Electrostatic Discharge.

  14. Materialism across the life span: An age-period-cohort analysis.

    PubMed

    Jaspers, Esther D T; Pieters, Rik G M

    2016-09-01

    This research examined the development of materialism across the life span. Two initial studies revealed that (a) lay beliefs were that materialism declines with age and (b) previous research findings also implied a modest, negative relationship between age and materialism. Yet, previous research has considered age only as a linear control variable, thereby precluding the possibility of more intricate relationships between age and materialism. Moreover, prior studies have relied on cross-sectional data and thus confound age and cohort effects. To improve on this, the main study used longitudinal data from 8 waves spanning 9 years of over 4,200 individuals (16 to 90 years) to examine age effects on materialism while controlling for cohort and period effects. Using a multivariate multilevel latent growth model, it found that materialism followed a curvilinear trajectory across the life span, with the lowest levels at middle age and higher levels before and after that. Thus, in contrast to lay beliefs, materialism increased in older age. Moreover, age effects on materialism differed markedly between 3 core themes of materialism: acquisition centrality, possession-defined success, and acquisition as the pursuit of happiness. In particular, acquisition centrality and possession-defined success were higher at younger and older age. Independent of these age effects, older birth cohorts were oriented more toward possession-defined success, whereas younger birth cohorts were oriented more toward acquisition centrality. The economic downturn since 2008 led to a decrease in acquisition as the pursuit of happiness and in desires for personal growth, but to an increase in desires for achievement. (PsycINFO Database Record PMID:27560768

  15. Aging-related tau astrogliopathy (ARTAG): harmonized evaluation strategy.

    PubMed

    Kovacs, Gabor G; Ferrer, Isidro; Grinberg, Lea T; Alafuzoff, Irina; Attems, Johannes; Budka, Herbert; Cairns, Nigel J; Crary, John F; Duyckaerts, Charles; Ghetti, Bernardino; Halliday, Glenda M; Ironside, James W; Love, Seth; Mackenzie, Ian R; Munoz, David G; Murray, Melissa E; Nelson, Peter T; Takahashi, Hitoshi; Trojanowski, John Q; Ansorge, Olaf; Arzberger, Thomas; Baborie, Atik; Beach, Thomas G; Bieniek, Kevin F; Bigio, Eileen H; Bodi, Istvan; Dugger, Brittany N; Feany, Mel; Gelpi, Ellen; Gentleman, Stephen M; Giaccone, Giorgio; Hatanpaa, Kimmo J; Heale, Richard; Hof, Patrick R; Hofer, Monika; Hortobágyi, Tibor; Jellinger, Kurt; Jicha, Gregory A; Ince, Paul; Kofler, Julia; Kövari, Enikö; Kril, Jillian J; Mann, David M; Matej, Radoslav; McKee, Ann C; McLean, Catriona; Milenkovic, Ivan; Montine, Thomas J; Murayama, Shigeo; Lee, Edward B; Rahimi, Jasmin; Rodriguez, Roberta D; Rozemüller, Annemieke; Schneider, Julie A; Schultz, Christian; Seeley, William; Seilhean, Danielle; Smith, Colin; Tagliavini, Fabrizio; Takao, Masaki; Thal, Dietmar Rudolf; Toledo, Jon B; Tolnay, Markus; Troncoso, Juan C; Vinters, Harry V; Weis, Serge; Wharton, Stephen B; White, Charles L; Wisniewski, Thomas; Woulfe, John M; Yamada, Masahito; Dickson, Dennis W

    2016-01-01

    Pathological accumulation of abnormally phosphorylated tau protein in astrocytes is a frequent, but poorly characterized feature of the aging brain. Its etiology is uncertain, but its presence is sufficiently ubiquitous to merit further characterization and classification, which may stimulate clinicopathological studies and research into its pathobiology. This paper aims to harmonize evaluation and nomenclature of aging-related tau astrogliopathy (ARTAG), a term that refers to a morphological spectrum of astroglial pathology detected by tau immunohistochemistry, especially with phosphorylation-dependent and 4R isoform-specific antibodies. ARTAG occurs mainly, but not exclusively, in individuals over 60 years of age. Tau-immunoreactive astrocytes in ARTAG include thorn-shaped astrocytes at the glia limitans and in white matter, as well as solitary or clustered astrocytes with perinuclear cytoplasmic tau immunoreactivity that extends into the astroglial processes as fine fibrillar or granular immunopositivity, typically in gray matter. Various forms of ARTAG may coexist in the same brain and might reflect different pathogenic processes. Based on morphology and anatomical distribution, ARTAG can be distinguished from primary tauopathies, but may be concurrent with primary tauopathies or other disorders. We recommend four steps for evaluation of ARTAG: (1) identification of five types based on the location of either morphologies of tau astrogliopathy: subpial, subependymal, perivascular, white matter, gray matter; (2) documentation of the regional involvement: medial temporal lobe, lobar (frontal, parietal, occipital, lateral temporal), subcortical, brainstem; (3) documentation of the severity of tau astrogliopathy; and (4) description of subregional involvement. Some types of ARTAG may underlie neurological symptoms; however, the clinical significance of ARTAG is currently uncertain and awaits further studies. The goal of this proposal is to raise awareness of

  16. Nondestructive evaluation of composite materials - A design philosophy

    NASA Technical Reports Server (NTRS)

    Duke, J. C., Jr.; Henneke, E. G., II; Stinchcomb, W. W.; Reifsnider, K. L.

    1984-01-01

    Efficient and reliable structural design utilizing fiber reinforced composite materials may only be accomplished if the materials used may be nondestructively evaluated. There are two major reasons for this requirement: (1) composite materials are formed at the time the structure is fabricated and (2) at practical strain levels damage, changes in the condition of the material, that influence the structure's mechanical performance is present. The fundamental basis of such a nondestructive evaluation capability is presented. A discussion of means of assessing nondestructively the material condition as well as a damage mechanics theory that interprets the material condition in terms of its influence on the mechanical response, stiffness, strength and life is provided.

  17. An evaluation of sex-age-kill (SAK) model performance

    USGS Publications Warehouse

    Millspaugh, Joshua J.; Skalski, John R.; Townsend, Richard L.; Diefenbach, Duane R.; Boyce, Mark S.; Hansen, Lonnie P.; Kammermeyer, Kent

    2009-01-01

    The sex-age-kill (SAK) model is widely used to estimate abundance of harvested large mammals, including white-tailed deer (Odocoileus virginianus). Despite a long history of use, few formal evaluations of SAK performance exist. We investigated how violations of the stable age distribution and stationary population assumption, changes to male or female harvest, stochastic effects (i.e., random fluctuations in recruitment and survival), and sampling efforts influenced SAK estimation. When the simulated population had a stable age distribution and λ > 1, the SAK model underestimated abundance. Conversely, when λ < 1, the SAK overestimated abundance. When changes to male harvest were introduced, SAK estimates were opposite the true population trend. In contrast, SAK estimates were robust to changes in female harvest rates. Stochastic effects caused SAK estimates to fluctuate about their equilibrium abundance, but the effect dampened as the size of the surveyed population increased. When we considered both stochastic effects and sampling error at a deer management unit scale the resultant abundance estimates were within ±121.9% of the true population level 95% of the time. These combined results demonstrate extreme sensitivity to model violations and scale of analysis. Without changes to model formulation, the SAK model will be biased when λ ≠ 1. Furthermore, any factor that alters the male harvest rate, such as changes to regulations or changes in hunter attitudes, will bias population estimates. Sex-age-kill estimates may be precise at large spatial scales, such as the state level, but less so at the individual management unit level. Alternative models, such as statistical age-at-harvest models, which require similar data types, might allow for more robust, broad-scale demographic assessments.

  18. Aging behavior of polymeric solar absorber materials - Part 1: Engineering plastics

    SciTech Connect

    Kahlen, S.; Wallner, G.M.; Lang, R.W.

    2010-09-15

    In this series of two papers, various polymeric materials are investigated as to their potential applicability as absorber materials for solar thermal collectors. The focus of the investigation is to study the aging behavior of these materials under maximum operating conditions (80 C in water up to 16,000 h) and stagnation conditions (140 C in air up to 500 h) typical for northern climate. The materials supplied or produced as polymer films were first characterized in the unaged state and then for different states of aging by differential scanning calorimetry (DSC), by size exclusion chromatography (SEC) and by mechanical tensile tests. Physical aging phenomena were studied by DSC, SEC analysis provided information on chemical degradation of the materials. In addition, physical and chemical aging were both analyzed via the small and large strain mechanical behavior. While the present Part 1 of this paper series deals with the aging behavior of engineering plastics, including two amorphous polymers (a polyphenylene ether polystyrene blend (PPE + PS) and polycarbonate (PC)) and two semi-crystalline polymers (two types of polyamide 12 (PA12)), the aging behavior of so-called ''commodity'' plastics (PE and PP) is the subject of Part 2. Comparing the two aging conditions, the amorphous materials (PPE + PS and PC) turned out to be more prone to physical and chemical aging at 140 C in air. In contrast, the semi-crystalline PA12 materials were more strongly affected by exposure to water at 80 C, although to different degrees, depending on the modification. (author)

  19. To Evaluate the Relationship between Mandibular Canine Calcification Stages and Skeletal Age

    PubMed Central

    Rana, Vivek; Rehani, Usha

    2012-01-01

    ABSTRACT Aim: The purpose of this study was to assess skeletal age and establish relationship between mandibular canine calcification and skeletal age. Materials and methods: The study included 147 females aged 10 to 13 years. The subjects were divided into three groups: Group I—comprising of 10 to 11 years old female; Group II—comprising of 11 to 12 years old female; Group III—12 to 13 years female. OPG and hand and wrist radiographs of left side for each subject were taken with prior consent of their parents. The calcification status of canine was evaluated from orthopantomograms according to scores given in Demirjian’s method. The stages of ossification of various carpal bones were evaluated using radiographic atlas of Greulich-Pyle and skeletal age was calculated. Results: Data collected was statistically analyzed. Conclusion: The results drawn from this study showed that a strong correlation was observed for canine calcification stage F for 10 to 11 years and for stage G in 11 to 12 years and 12 to 13 years respectively. How to cite this article: Malik P, Rana V, Rehani U. To Evaluate the Relationship between Mandibular Canine Calcification Stages and Skeletal Age. Int J Clin Pediatr Dent 2012;5(1): 14-19. PMID:25206128

  20. 20 CFR 416.924b - Age as a factor of evaluation in the sequential evaluation process for children.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Determining Disability and Blindness Evaluation of Disability § 416.924b Age as a factor of evaluation in the sequential...

  1. 20 CFR 416.924b - Age as a factor of evaluation in the sequential evaluation process for children.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ADMINISTRATION SUPPLEMENTAL SECURITY INCOME FOR THE AGED, BLIND, AND DISABLED Determining Disability and Blindness Evaluation of Disability § 416.924b Age as a factor of evaluation in the sequential...

  2. A microcalorimeter used to detect changes in aged energetic materials

    SciTech Connect

    Wiedenheft, C.J.; Rodenburg, W.W.; Shockey, G.C.

    1987-01-01

    To ensure the quality of chemical explosives, analytical tests are performed on the materials. One of the most fundamental measurements is that of heat released during an exothermic reaction. Because only small amounts, less than 20 mg, of explosive material can be removed from most weapons, special techniques and instruments must be used to measure a heat output of a few tens of calories. The calorimeter described in this report consists of a sample side and a reference side placed in a constant temperature bath. The calorimeter and sample are heated by passing the current from a bank of capacitors through a heating wire. In order to measure the temperature change, the resistance of Ni wire is measured. The unit was calibrated and found to be accurate for reactions with greater than 5 calories of heat output. (JDH)

  3. Environmental Effects on ISS Materials Aging (1998 to 2008)

    NASA Technical Reports Server (NTRS)

    Alred, John; Dasgupta, Rajib; Koontz, Steve; Soares, Carlos; Golden, John

    2009-01-01

    The performance of ISS spacecraft materials and systems on prolonged exposure to the low- Earth orbit (LEO) space flight are reported in this paper. In-flight data, flight crew observations, and the results of ground-based test and analysis directly supporting programmatic and operational decision-making are described. The space flight environments definitions (both natural and induced) used for ISS design, material selection, and verification testing are shown, in most cases, to be more severe than the actual flight environment accounting, in part, for the outstanding performance of ISS as a long mission duration spacecraft. No significant ISS material or system failures have been attributed to spacecraft-environments interactions. Nonetheless, ISS materials and systems performance data is contributing to our understanding of spacecraft material interactions with the spaceflight environment so as to reduce cost and risk for future spaceflight projects and programs. Orbital inclination (51.6 deg) and altitude (nominally near 360 km) determine the set of natural environment factors affecting the functional life of materials and systems on ISS. ISS operates in an electrically conducting environment (the F2 region of Earth s ionosphere) with well-defined fluxes of atomic oxygen, other charged and neutral ionospheric plasma species, solar UV, VUV, and x-ray radiation as well as galactic cosmic rays, trapped radiation, and solar cosmic rays. The LEO micrometeoroid and orbital debris environment is an especially important determinant of spacecraft design and operations. The magnitude of several environmental factors varies dramatically with latitude and longitude as ISS orbits the Earth. The high latitude orbital environment also exposes ISS to higher fluences of trapped energetic electrons, auroral electrons, solar cosmic rays, and galactic cosmic rays than would be the case in lower inclination orbits, largely as a result of the overall shape and magnitude of the

  4. Photochemical aging of light-absorbing secondary organic aerosol material.

    PubMed

    Sareen, Neha; Moussa, Samar G; McNeill, V Faye

    2013-04-11

    Dark reactions of methylglyoxal with NH4(+) in aqueous aerosols yield light-absorbing and surface-active products that can influence the physical properties of the particles. Little is known about how the product mixture and its optical properties will change due to photolysis as well as oxidative aging by O3 and OH in the atmosphere. Here, we report the results of kinetics and product studies of the photochemical aging of aerosols formed by atomizing aqueous solutions of methylglyoxal and ammonium sulfate. Experiments were performed using aerosol flow tube reactors coupled with an aerosol chemical ionization mass spectrometer (Aerosol-CIMS) for monitoring gas- and particle-phase compositions. Particles were also impacted onto quartz windows in order to assess changes in their UV-visible absorption upon oxidation. Photooxidation of the aerosols leads to the formation of small, volatile organic acids including formic acid, acetic acid, and glyoxylic acid. The atmospheric lifetime of these species during the daytime is predicted to be on the order of minutes, with photolysis being an important mechanism of degradation. The lifetime with respect to O3 oxidation was observed to be on the order of hours. O3 oxidation also leads to a net increase in light absorption by the particles due to the formation of additional carbonyl compounds. Our results are consistent with field observations of high brown carbon absorption in the early morning. PMID:23506538

  5. Evaluation of Skin Ageing Through Wrinkle Analysis in Capacitive Images

    NASA Astrophysics Data System (ADS)

    Bevilacqua, Alessandro; Gherardi, Alessandro; Guerrieri, Roberto

    Quantitative evaluation of the changes in skin topographic structures are of great importance in the dermocosmetic field to assess subjects response to medical or cosmetic treatments. Although many devices and methods are known to measure these changes, they are not suitable for a routine approach and most of them are invasive. Moreover, it has always been difficult to give a measure of the skin health status as well as of the human aging process by simply analyzing the skin surface appearance. This work describes how a portable capacitive device could be utilized to achieve measurements of skin ageing in vivo and routinely. The capacitive images give a high resolution representation of the skin micro-relief, both in terms of skin surface tissue and wrinkles. In a previous work we dealt with the former; here we have addressed the latter. The algorithm we have developed allowed us to extract two original features from wrinkles: the first is based on photometric properties while the second has been achieved through the multiresolution analysis of the wavelet transform. Accurate experiments accomplished on 87 subjects show how the features we conceived are related to skin ageing.

  6. A Sourcebook for the Evaluation of Instructional Materials and Media.

    ERIC Educational Resources Information Center

    Armstrong, Jenny R., Ed.

    Described is a generalized model for the evaluation of instructional materials and media designed to be usable by the Instructional Materials Centers/Regional Media Centers/Regional Resource Centers Network. The model is described as a guide to the inclusion of the critical elements in an evaluation problem situation. Discussed are a system for…

  7. Weightless Environment Training Facility (WETF) materials coating evaluation, volume 2

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This volume consists of Appendices A and B to the report on the Weightless Environment Training Facility Materials Coating Evaluation project. The project selected 10 coating systems to be evaluated in six separate exposure environments, and subject to three tests for physical properties. Appendix A holds the coating system, surface preparation, and application data. Appendix B holds the coating material infrared spectra.

  8. Evaluation of advanced materials. Final report

    SciTech Connect

    Wright, I.G.; Clauer, A.H.; Shetty, D.K.; Tucker, T.R.; Stropki, J.T.

    1982-11-18

    Cemented tungsten carbides with a binder level in the range of 5 to 6 percent exhibited the best resistance to erosion for this class of materials. Other practical cermet meterials were diamond - Si/SiC, Al/sub 2/O/sub 3/-B/sub 4/C-Cr, and B/sub 4/C-Co. SiAlON exhibited erosion resistance equivalent to the best WC-cermet. The only coating system to show promise of improved erosion resistance was CVD TiB/sub 2/ on cemented TiB/sub 2/-Ni. Cracking and/or spalling of a TiC coating and a proprietary TMT coating occurred in the standard slurry erosion test. Ranking of cemented tungsten carbide materials in the laboratory erosion test was the same as that found in service in the Wilsonville pilot plant. Specimens from the Fort Lewis pilot plant which performed well in service exhibited low erosion in the laboratory test. A substitute slurry, was found to be 2 to 4 times more erosive than the coal-derived slurry 8 wt% solids. Ranking of materials in the substitute slurry was nearly identical to that in the coal-derived slurry. Three modes of erosion were: ductile cutting; elastic-plastic indentation and fracture; and intergranular fracture. Erosion of a given material was closely related to its microstructure. In the substitute slurry, the angle-dependence of erosion of two forms of SiC, hot-pressed and sintered, were similar, but the sintered material eroded slower. Laser fusing of preplaced powder mixtures can produce cermet-like structures with potential for erosive and sliding wear resistance. TiC particles in Stellite 6 matrix proved less prone to cracking than WC particles in the same matrix. 74 figures, 14 tables.

  9. Design and evaluation of lost circulation materials for severe environments

    SciTech Connect

    Loeppke, G.E.; Glowka, D.A.; Wright, E.K.

    1988-01-01

    An independent analysis of lost circulation materials for geothermal applications has been completed using unique laboratory tools developed for the purpose. Test results of commercial materials as well as mathematical models for evaluating their performance are presented. Physical attributes that govern the performance of lost circulation materials are identified and correlated with test results. 9 refs., 27 figs., 4 tabs.

  10. Evaluation of oxidative behavior of polyolefin geosynthetics utilizing accelerated aging tests based on temperature and pressure

    NASA Astrophysics Data System (ADS)

    Li, Mengjia

    Polyolefin geosynthetics are susceptible to oxidation, which eventually leads to the reduction in their engineering properties. In the application of polyolefin geosynthetics, a major issue is an estimate of the materials durability (i.e. service lifetime) under various aging conditions. Antioxidant packages are added to the polyolefin products to extend the induction time, during which antioxidants are gradually depleted and polymer oxidation reactions are prevented. In this PhD study, an improved laboratory accelerating aging method under elevated and high pressure environments was applied to evaluate the combined effect of temperature and pressure on the depletion of the antioxidants and the oxidation of polymers. Four types of commercial polyolefn geosynthetic materials selected for aging tests included HDPE geogrid, polypropylene woven and nonwoven geotextiles. A total of 33 different temperature/pressure aging conditions were used, with the incubation duration up to 24 months. The applied oven temperature ranged from 35°C to 105°C and the partial oxygen pressure ranged from 0.005 MPa to 6.3 MPa. Using the Oxidative Induction Time (OIT) test, the antioxidant depletion, which is correlated to the decrease of the OIT value, was found to follow apparent first-order decay. The OIT data also showed that, the antioxidant depletion rate increased with temperature according to the Arrhenius equation, while under constant temperatures, the rate increased exponentially with the partial pressure of oxygen. A modified Arrhenius model was developed to fit the antioxidant depletion rate as a function of temperature and pressure and to predict the antioxidant lifetime under various field conditions. This study has developed new temperature/pressure incubation aging test method with lifetime prediction models. Using this new technique, the antioxidant lifetime prediction results are close to regular temperature aging data while the aging duration can be reduced considerably

  11. Application of Ultrasonic Guided Waves for Evaluating Aging Wire Insulation

    NASA Technical Reports Server (NTRS)

    Anastasi, Robert F.; Madaras, Eric I.

    2005-01-01

    Aging wiring has become a critical issue to the aerospace and aircraft industries due to Shuttle and aircraft incidents. The problem is that over time the insulation on wire becomes brittle and cracks. This exposes the underlying conductive wire to the potential for short circuits and fire. Popular methods of monitoring aging wire problems focuses on applying electrical sensing techniques that are sensitive to the conductor's condition, but not very sensitive to the wire insulation's condition. Measurement of wire insulation stiffness and ultrasonic properties by ultrasonic guided waves is being examined. Experimental measurements showed that the lowest order extensional mode could be sensitive to stiffness changes in the wire insulation. To test this theory conventional wire samples were heat damaged in an oven, in a range of heating conditions. The samples were 12, 16, and 20 gauge and the heat damage introduced material changes in the wire insulation that made the originally flexible insulation brittle and darker in color. Results showed that extensional mode phase velocity increased for the samples that were exposed to heat for longer duration.

  12. Quantitative nondestructive evaluation of materials and structures

    NASA Technical Reports Server (NTRS)

    Smith, Barry T.

    1991-01-01

    An experimental investigation was undertaken to quantify damage tolerance and resistance in composite materials impacted using the drop-weight method. Tests were conducted on laminates of several different carbon-fiber composite systems, such as epoxies, modified epoxies, and amorphous and semicrystalline thermoplastics. Impacted composite specimens were examined using destructive and non-destructive techniques to establish the characteristic damage states. Specifically, optical microscopy, ultrasonic, and scanning electron microscopy techniques were used to identify impact induced damage mechanisms. Damage propagation during post impact compression was also studied.

  13. Age effects on load-dependent brain activations in working memory for novel material

    PubMed Central

    Holtzer, Roee; Rakitin, Brian, C.; Steffener, Jason; Flynn, Joe; Kumar, Arjun; Stern, Yaakov

    2009-01-01

    Three competing models of cognitive aging (neural compensation, capacity limitations, neural inefficiency) were examined in relation to working memory for novel non-verbal material. To accomplish this goal young (n=25) and old (n=25) participants performed a delayed item recognition (DIR) task while being scanned with bold fMRI. The stimuli in the DIR task consisted of computer-generated closed-curve shapes with each shape presented only once in the testing conditions of each participant. This ensured that both the novelty and appearance of the shapes maximized visual demands and limited the extent of phonologic processing. Behaviorally, as expected, the old participants were slower and less accurate compared to the young participants. Spatial patterns of brain activation that corresponded to load-dependent (stimulus set size ranged from 1 to 3) fMRI signal during the three phases of the DIR task (memory set presentation, retention delay, probe presentation) were evaluated in both age groups. Support for neural compensation and capacity limitation was evident in retention delay and the probe phase, respectively. Data were inconsistent with the neural inefficiency model. The process specific support for the theories we examined is consistent with a large corpus of research showing that the substrates underlying the encoding, retention and probe phases are different. That is, cognitive aging theories can be specific to the neural networks/regions underlying the different phases of working memory. Delineating how these theories work in concert can increase knowledge of age-related effects on working memory. PMID:18983833

  14. Understanding and controlling low-temperature aging of nanocrystalline materials.

    SciTech Connect

    Battaile, Corbett Chandler; Boyce, Brad Lee; Brons, Justin G.; Foiles, Stephen Martin; Hattar, Khalid Mikhiel; Holm, Elizabeth Ann; Padilla, Henry A.,; Sharon, John Anthony; Thompson, Gregory B.

    2013-10-01

    Nanocrystalline copper lms were created by both repetitive high-energy pulsed power, to produce material without internal nanotwins; and pulsed laser deposition, to produce nan- otwins. Samples of these lms were indented at ambient (298K) and cryogenic temperatures by immersion in liquid nitrogen (77K) and helium (4K). The indented samples were sectioned through the indented regions and imaged in a scanning electron microscope. Extensive grain growth was observed in the lms that contained nanotwins and were indented cryogenically. The lms that either lacked twins, or were indented under ambient conditions, were found to exhibit no substantial grain growth by visual inspection. Precession transmission elec- tron microscopy was used to con rm these ndings quantitatively, and show that 3 and 7 boundaries proliferate during grain growth, implying that these interface types play a key role in governing the extensive grain growth observed here. Molecular dynamics sim- ulations of the motion of individual grain boundaries demonstrate that speci c classes of boundaries - notably 3 and 7 - exhibit anti- or a-thermal migration, meaning that their mobilities either increase or do not change signi cantly with decreasing temperature. An in-situ cryogenic indentation capability was developed and implemented in a transmission electron microscope. Preliminary results do not show extensive cryogenic grain growth in indented copper lms. This discrepancy could arise from the signi cant di erences in con g- uration and loading of the specimen between the two approaches, and further research and development of this capability is needed.

  15. Investigation of Aging Processes of Ti-6Al-4 V Powder Material in Laser Melting

    NASA Astrophysics Data System (ADS)

    Seyda, V.; Kaufmann, N.; Emmelmann, C.

    Laser melting of titanium material, e.g. Ti-6Al-4 V, offers great potential in manufacturing automotive components, lightweight structures and medical implants. In order to achieve required mechanical properties of laser melted components quality of powder materials is essential. Unmelted powder is recycled and reused in a subsequent process. Due to repeated recycling it is suggested that powder material changes. In this paper aging processes of Ti-6Al-4 V powder are studied. It was observed that powder particles coarsen and flowability increases. Comparing examined powder characteristics to bulk material properties it was noticed that there are significant effects of aged powder on laser melted components.

  16. Evaluation of materials and design modifications for aircraft brakes

    NASA Technical Reports Server (NTRS)

    Ho, T. L.; Kennedy, F. E.; Peterson, M. B.

    1975-01-01

    A test program is described which was carried out to evaluate several proposed design modifications and several high-temperature friction materials for use in aircraft disk brakes. The evaluation program was carried out on a specially built test apparatus utilizing a disk brake and wheel half from a small het aircraft. The apparatus enabled control of brake pressure, velocity, and braking time. Tests were run under both constant and variable velocity conditions and covered a kinetic energy range similar to that encountered in aircraft brake service. The results of the design evaluation program showed that some improvement in brake performance can be realized by making design changes in the components of the brake containing friction material. The materials evaluation showed that two friction materials show potential for use in aircraft disk brakes. One of the materials is a nickel-based sintered composite, while the other is a molybdenum-based material. Both materials show much lower wear rates than conventional copper-based materials and are better able to withstand the high temperatures encountered during braking. Additional materials improvement is necessary since both materials show a significant negative slope of the friction-velocity curve at low velocities.

  17. Aging behavior of polymeric solar absorber materials - Part 2: Commodity plastics

    SciTech Connect

    Kahlen, S.; Wallner, G.M.; Lang, R.W.

    2010-09-15

    In this series of two papers, various polymeric materials are investigated as to their potential applicability as absorber materials for solar thermal collectors. While Part 1 of this paper series deals with the aging behavior of engineering plastics, including two amorphous polymers (PPE + PS) and (PC) and two semi-crystalline polymers (two types of PA12), the present Part 2 treats the aging behavior of semi-crystalline so-called ''commodity'' plastics (two types of crosslinked polyethylene (PE-X) and two types of polypropylene (PP)). As in Part 1, the focus of the investigation is to study the aging behavior of these materials under maximum operating conditions (80 C in water up to 16,000 h) and stagnation conditions (140 C in air up to 500 h) typical for northern climate. The materials supplied or produced as polymer films were first characterized in the unaged state and then for different states of aging by differential scanning calorimetry (DSC), by size exclusion chromatography (SEC) and by mechanical tensile tests. DSC was applied primarily to obtain information on physical aging phenomena, whereas SEC analysis was used to characterize chemical degradation of the materials. In addition, physical and chemical aging were both analyzed via the small and large strain mechanical behavior. Comparing the two aging conditions in hot air and hot water, a rather stable mechanical performance profile was found for both PP types over the investigated aging time, which was interpreted in terms of competing physical and chemical aging mechanisms. Analogously such competing mechanisms were also inferred for one of the PE-X materials, while the other exhibited substantial degradation in terms of strain-to-break values for both aging conditions. In principle, both PP and PE-X are promising candidates for black absorber applications in northern climates if proper measures against overheating are taken and when adequately modified. (author)

  18. Evaluation of the bond strength between aged composite cores and luting agent

    PubMed Central

    2015-01-01

    PURPOSE The aim of this study was to evaluate effect of different surface treatment methods on the bond strength between aged composite-resin core and luting agent. MATERIALS AND METHODS Seventy-five resin composites and also seventy-five zirconia ceramic discs were prepared. 60 composite samples were exposed to thermal aging (10,000 cycles, 5 to 55℃) and different surface treatment. All specimens were separated into 5 groups (n=15): 1) Intact specimens 2) Thermal aging-air polishing 3) Thermal aging- Er:YAG laser irradiation 4) Thermal aging- acid etching 5) Thermal-aging. All specimens were bonded to the zirconia discs with resin cement and fixed to universal testing machine and bond strength testing loaded to failure with a crosshead speed of 0.5 mm/min. The fractured surface was classified as adhesive failure, cohesive failure and adhesive-cohesive failure. The bond strength data was statistically compared by the Kruskal-Wallis method complemented by the Bonferroni correction Mann-Whitney U test. The probability level for statistical significance was set at α=.05. RESULTS Thermal aging and different surface treatment methods have significant effect on the bond strength between composite-resin cores and luting-agent (P<.05). The mean baseline bond strength values ranged between 7.07 ± 2.11 and 26.05 ± 6.53 N. The highest bond strength of 26.05 ± 6.53 N was obtained with Group 3. Group 5 showed the lowest value of bond strength. CONCLUSION Appropriate surface treatment method should be applied to aged composite resin cores or aged-composites restorations should be replaced for the optimal bond strength and the clinical success. PMID:25932308

  19. Method and Apparatus for Non-Destructive Evaluation of Materials

    NASA Technical Reports Server (NTRS)

    Goldfine, Neil J. (Inventor); Washabaugh, Andrew P. (Inventor); Lyons, Robert (Inventor); Thomas, Zachary (Inventor); Jablonski, David A. (Inventor); Martin, Christopher (Inventor)

    2015-01-01

    Methods and apparatus for characterizing composite materials for manufacturing quality assurance (QA), periodic inspection during the useful life, or for forensic analysis/material testing. System are provided that relate eddy-current sensor responses to the fiber layup of a composite structure, the presence of impact damage on a composite structure with or without a metal liner, volumetric stress within the composite, fiber tow density, and other NDE inspection requirements. Also provided are systems that determine electromagnetic material properties and material dimensions of composite materials from capacitive sensor inspection measurements. These properties are related to the presence of buried defects in non-conductive composite materials, moisture ingress, aging of the material due to service or environmental/thermal exposure, or changes in manufacturing quality.

  20. Durability evaluation techniques and modeling for highway materials

    SciTech Connect

    Biswas, M.; Muchane, G.K.

    1995-06-01

    For satisfactory long-term performance of highway facilities, the authors are concerned about durability of materials, in addition to their initial strength. Besides conventional materials, such as Portland cement concrete and asphalt concrete, their interests include high-performance materials such as polymer concrete and polymer modified concrete. Degradation of materials may occur over time due to exposure to a number of aggravating conditions and environments. For investigation of durability, the aggravating exposures that the authors have considered include repeated loading, freeze-thaw cycling. Methods of evaluation of performance of materials include application of vibration spectral techniques for evaluating of material stiffness and damage. Materials are modeled to characterize their performance under repeated loads and other aggravating exposures.

  1. Tribological evaluation and analysis of coating materials

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1992-01-01

    A physical characterization of coating materials by analytical techniques such as XPS, AES, ellipsometry, and nuclear reaction analysis can contribute to the understanding of adhesion and friction of the coatings and can partially predict the tribological properties of the coatings. This two-part paper describes the tribological properties and physical characteristics of (1) diamondlike carbon (DLC) films and (2) silicon nitride (SiN(x)) films. Emphasis is to relate plasma deposition conditions to the film chemistry and composition and to the adhesion and friction of the films. With the DLC films, the higher the plasma deposition power, the less the hydrogen concentration and the greater the film density and the hardness. The friction behavior of DLC films deposited at higher deposition powers (200 to 300 W) is similar to that of bulk diamond. Even in a vacuum, the DLC films effectively lubricate ceramic surfaces (Si3N4) at temperatures to 500 C. With SiN(x) films, the silicon to nitrogen ratios and the amount of amorphous silicon depend on deposition frequency. The presence of rich amorphous silicon in the high-frequency plasma-deposited SiN(x) films increases their adhesion and friction above 500 C in vacuum.

  2. Evaluation criteria for commercially oriented materials processing in space proposals

    NASA Technical Reports Server (NTRS)

    Moore, W. F.; Mcdowell, J. R.

    1979-01-01

    An approach and criteria for evaluating NASA funded experiments and demonstrations which have commercial potential were developed. Methods for insuring quick initial screening of commercial proposals are presented. Recommendations are given for modifying the current evaluation approach. New criteria for evaluating commercially orientated materials processing in space (MPS) proposals are introduced. The process for selection of qualified individuals to evaluate the phases of this approach and criteria is considered and guidelines are set for its implementation.

  3. Sensory evaluation of a novel vegetable in school age children.

    PubMed

    Coulthard, Helen; Palfreyman, Zoe; Morizet, David

    2016-05-01

    A behavioural sensory task was undertaken to further understanding into whether children's sensory evaluation of a new vegetable is associated with tasting and food neophobia scores. A sample of ninety-five children, aged 7-11 years, was recruited from a primary school in inner city Birmingham, UK. They were asked to rate the sight, smell and feel of a familiar vegetable (carrot) and an unfamiliar vegetable (celeriac) in a randomised order to control for order effects. They were then asked to try the each vegetable, and rate its taste. It was found that children rated the sensory characteristics of the familiar vegetable more positively than the novel vegetable across all sensory domains (p < 0.05). Refusing to try the novel vegetable was associated with food neophobia scores and olfactory ratings. The ratings of the taste of the novel vegetable were associated with olfactory and tactile ratings. In addition there was a clear developmental shift in the sample with younger children being more likely to rate the novel vegetable as 'looking strange' and older children rating the novel vegetable as 'smelling strange'. This research strengthens the idea that sensory information is important in children deciding to try, and their hedonic evaluation of the taste of a new vegetable. PMID:26809143

  4. Ultrasonic and radiographic evaluation of advanced aerospace materials: Ceramic composites

    NASA Technical Reports Server (NTRS)

    Generazio, Edward R.

    1990-01-01

    Two conventional nondestructive evaluation techniques were used to evaluate advanced ceramic composite materials. It was shown that neither ultrasonic C-scan nor radiographic imaging can individually provide sufficient data for an accurate nondestructive evaluation. Both ultrasonic C-scan and conventional radiographic imaging are required for preliminary evaluation of these complex systems. The material variations that were identified by these two techniques are porosity, delaminations, bond quality between laminae, fiber alignment, fiber registration, fiber parallelism, and processing density flaws. The degree of bonding between fiber and matrix cannot be determined by either of these methods. An alternative ultrasonic technique, angular power spectrum scanning (APSS) is recommended for quantification of this interfacial bond.

  5. Evaluation of Eco-Efficiency and Performance of Retrofit Materials

    NASA Astrophysics Data System (ADS)

    Gopinath, Smitha; Rama Chandra Murthy, A.; Iyer, Nagesh R.; Kokila, S.

    2015-12-01

    In this work three materials namely Fiber Reinforced Polymer (FRP), ferrocement and Textile Reinforced Concrete (TRC) have been evaluated towards their performance efficiency and eco-effectiveness for sustainable retrofitting applications. Investigations have been carried out for flexural strengthening of RC beams with FRP, ferrocement and TRC. It is observed that in the case of FRP, it is not possible to tailor the material according to design requirements and most of the time strengthened structure becomes over stiff. Eco-effectiveness of these retrofitting materials has been evaluated by computing the embodied energy. It is observed that the amount of CO2 emitted by TRC is less compared to other retrofit materials. Further, the performance point of retrofitted RC frames has been evaluated and damage index has been calculated to find out the effective retrofit material. It is concluded that, if RC frame is retrofitted with FRP and TRC, it undergoes less damage compared to ferrocement.

  6. Concepts and techniques for ultrasonic evaluation of material mechanical properties

    NASA Technical Reports Server (NTRS)

    Vary, A.

    1980-01-01

    The ultrasonic nondestructive evaluation techniques discussed in the present paper indicate potentials for material characterization and property prediction. Stress wave interaction and material transfer function concepts are examined as a basis for explaining correlations between material mechanical behavior and ultrasonically measured quantities. It is observed that the effect and criticality of any discrete flaw, such as crack, inclusion, or any other stress raiser, is definable only in terms of its material microstructural environment. This underscores the importance of ultrasonic techniques capable of characterizing the stress wave energy transfer properties of a material.

  7. Acceleration factors for oxidative aging of polymeric materials by oxygen detection.

    SciTech Connect

    Assink, Roger Alan; Celina, Mathias Christopher; Skutnik, Julie Michelle

    2005-01-01

    Three methods that were used to measure the chemical changes associated with oxidative degradation of polymeric materials are presented. The first method is based on the nuclear activation of {sup 18}O in an elastomer that was thermally aged in an {sup 18}O{sub 2} atmosphere. Second, the alcohol groups in a thermally aged elastomer were derivatized with trifluoroacetic anhydride and their concentration measured via {sup 19}F NMR spectroscopy. Finally, a respirometer was used to directly measure the oxidative rates of a polyurethane foam as a function of aging temperature. The measurement of the oxidation rates enabled acceleration factors for oxidative degradation of these materials to be calculated.

  8. Evaluation and clinical significance of the stomach age model for evaluating aging of the stomach-a multicenter study in China

    PubMed Central

    2014-01-01

    Background A higher prevalence of chronic atrophic gastritis (CAG) occurs in younger adults in Asia. We used Stomach Age to examine the different mechanisms of CAG between younger adults and elderly individuals, and established a simple model of cancer risk that can be applied to CAG surveillance. Methods Stomach Age was determined by FISH examination of telomere length in stomach biopsies. Δψm was also determined by flow cytometry. Sixty volunteers were used to confirm the linear relationship between telomere length and age while 120 subjects were used to build a mathematical model by a multivariate analysis. Overall, 146 subjects were used to evaluate the validity of the model, and 1,007 subjects were used to evaluate the relationship between prognosis and Δage (calculated from the mathematical model). ROC curves were used to evaluate the relationship between prognosis and Δage and to determine the cut-off point for Δage. Results We established that a tight linear relationship between the telomere length and the age. The telomere length was obvious different between patients with and without CAG even in the same age. Δψm decreased in individuals whose Stomach Age was greater than real age, especially in younger adults. A mathematical model of Stomach Age (real age + Δage) was successfully constructed which was easy to apply in clinical work. A higher Δage was correlated with a worse outcome. The criterion of Δage >3.11 should be considered as the cut-off to select the subgroup of patients who require endoscopic surveillance. Conclusion Variation in Stomach Age between individuals of the same biological age was confirmed. Attention should be paid to those with a greater Stomach Age, especially in younger adults. The Δage in the Simple Model can be used as a criterion to select CAG patients for gastric cancer surveillance. PMID:25057261

  9. Study on the Aging Behaviors of Rubber Materials in Tension and Compression Loads

    NASA Astrophysics Data System (ADS)

    Jiang, Can; Wang, Hongyu; Ma, Xiaobing

    Rubber materials are widely used in aviation, aerospace, shipbuilding, automobile and other military field. However, rubber materials are easy to aging, which largely restricts its using life. In working environment, due to the combined effect of heat and oxygen, vulcanized rubber will undergo degradation and crosslinking reaction which will cause elasticity decease and permanent deformation, so mostly rubber products are used under stress state. Due to the asymmetric structure and asymmetric stress distribution, mechanical stress may cause serious damage to molecular structure; therefore, this paper is aimed to analyze the aging behavior of rubber materials under tensile and compressive loadings, through analyzing experiment data, and adopting Gauss function to describe stress relaxation coefficient, to build an aging equation containing compression ratio parameter and aging time.

  10. Evaluating Course Design Principles for Multimedia Learning Materials

    ERIC Educational Resources Information Center

    Scott, Bernard; Cong, Chunyu

    2010-01-01

    Purpose: This paper aims to report on evaluation studies of principles of course design for interactive multimedia learning materials. Design/methodology/approach: At the Defence Academy of the UK, Cranfield University has worked with military colleagues to produce multimedia learning materials for courses on "Military Knowledge". The courses are…

  11. Material evaluation program, high-temperature nitriding environment

    NASA Technical Reports Server (NTRS)

    Marcy, R. D.

    1973-01-01

    Results of a program conducted to evaluate materials for construction of a space shuttle hydrazine monopropellant gas generator are presented. The program was designed to select those materials that maintain the properties of strength and ductility after exposure to an 1800 F nitriding environment for 1000 hours.

  12. A Procedure to Evaluate Cognitive Requirements of Beginning Reading Materials.

    ERIC Educational Resources Information Center

    Williams, Connie K.

    Designed to assess the cognitive requirement expected or implied in beginning reading materials and in their instructional suggestions and to determine whether these materials are appropriate to the cognitive development of the children who will use them, this instrument is for use by evaluators with the first reader in a basal series. It directs…

  13. Identification and Assessment of Material Models for Age-Related Degradation of Structures and Passive Components in Nuclear Power Plants

    SciTech Connect

    Nie,J.; Braverman, J.; Hofmayer, C.; Kim, M. K.; Choi, I-K.

    2009-04-27

    When performing seismic safety assessments of nuclear power plants (NPPs), the potential effects of age-related degradation on structures, systems, and components (SSCs) should be considered. To address the issue of aging degradation, the Korea Atomic Energy Research Institute (KAERI) has embarked on a five-year research project to develop a realistic seismic risk evaluation system which will include the consideration of aging of structures and components in NPPs. Three specific areas that are included in the KAERI research project, related to seismic probabilistic risk assessment (PRA), are probabilistic seismic hazard analysis, seismic fragility analysis including the effects of aging, and a plant seismic risk analysis. To support the development of seismic capability evaluation technology for degraded structures and components, KAERI entered into a collaboration agreement with Brookhaven National Laboratory (BNL) in 2007. The collaborative research effort is intended to continue over a five year period with the goal of developing seismic fragility analysis methods that consider the potential effects of age-related degradation of SSCs, and using these results as input to seismic PRAs. In the Year 1 scope of work BNL collected and reviewed degradation occurrences in US NPPs and identified important aging characteristics needed for the seismic capability evaluations that will be performed in the subsequent evaluations in the years that follow. This information is presented in the Annual Report for the Year 1 Task, identified as BNL Report-81741-2008 and also designated as KAERI/RR-2931/2008. The report presents results of the statistical and trending analysis of this data and compares the results to prior aging studies. In addition, the report provides a description of U.S. current regulatory requirements, regulatory guidance documents, generic communications, industry standards and guidance, and past research related to aging degradation of SSCs. This report

  14. Absolute age of lunar regolith material from the Sea of Fertility

    NASA Technical Reports Server (NTRS)

    Vinogradov, A. P.; Artemov, Y. M.

    1974-01-01

    By averaging the absolute age of lunar regolith materials from the Sea of Fertility for the fine regolith fraction from the core zone V, an age of 4.65 10 to the 9th power + 0.4 10 to the 9th power years was obtained, employing as the primordial Sr-87/Sr-86 ratio 0.69884 (ADOR). Also close to this age value is the age estimate based on the Pb-207/Pb-206 ratio. Using the value 0.69898 (BABI) as a primordial Sr-87/Sr-86 ratio reduces the calculated age of the fine regolith fraction to 4.25 X 10 to the 9th power years. The fine fraction of lunar regolith from the Sea of Fertility is also characterized by a minimum addition of radiogenic Sr-87, a minimum Rb/Sr ratio, and a maximum K/Rb ratio compared with analogous lunar material from other points.

  15. A micro-continuum-mechanical material model for failure of rubber-like materials: Application to ageing-induced fracturing

    NASA Astrophysics Data System (ADS)

    Dal, Hüsnü; Kaliske, Michael

    2009-08-01

    Rubbery polymers are subjected to severe environmental conditions under service. As a consequence of various ageing mechanisms, the outer surface of rubber components hardens in time and cracking occurs as a result of combined mechanical and chemical processes. Conventional phenomenological hyperelastic constitutive models do not account for material softening. Consequently, the stored energy and stresses tend to infinity as stretch increases. In this contribution, a network alteration for the ageing mechanism of rubber-like materials is introduced along with a micromolecular description of material failure. The proposed micro-continuum material model is based on a serial construction of a Langevin-type spring representing the energy storage owing to conformational changes induced by deformation, to a bond potential representing the energy stored in the polymer chain due to the interatomic displacement. For the representation of the micro-macro transition, the non-affine kinematics of the micro-sphere model is used. The Morse potential is utilized for the interatomic bond, which describes the energetic contribution to rubber-like materials and governs the failure of the polymer chain in terms of bond rupture. A novel numerical scheme for the FE implementation of the proposed model is demonstrated. The hardening phenomenon as a result of diffusion limited oxidation of rubber is explained by the principle of mass conservation which dictates simultaneous modulus hardening along with decrease in ultimate stretch observed in aged rubbery polymers.

  16. Influence of the humidity on leakage current under accelerated aging of polymer insulating materials

    SciTech Connect

    Otsubo, M.; Shimono, Y.; Hikami, T.; Honda, C.

    1996-12-31

    This paper describes the experimental results of accelerated aging tests conducted on three different types of polymer materials. Salt fog chamber tests were used to study the surface degradation modes for all materials. The work presented here was performed using a newly constructed fog chamber system that was able to control both chamber humidity and UV radiation. The changes in the surface morphology, material structure and leakage current were examined to study the influence of environmental humidity.

  17. Standards for Evaluations of Educational Programs, Projects, and Materials.

    ERIC Educational Resources Information Center

    Stufflebeam, Daniel L.

    Thirty specific standards developed as guiding principles to maintain the utility, feasibility, propriety and accuracy of evaluations in educational programs, projects and materials are presented. Utility Standards include Audience Identification, Evaluator Credibility, Information Scope and Selection, Valuational Interpretation, Report Clarity,…

  18. Evaluation of Composite Materials for Use on Launch Complexes

    NASA Technical Reports Server (NTRS)

    Finchum, A.; Welch, Peter J.

    1989-01-01

    Commercially available composite structural shapes were evaluated for use. These composites, fiberglass-reinforced polyester and vinylester resin materials are being used extensively in the fabrication and construction of low maintenance, corrosion resistant structures. The evaluation found that in many applications these composite materials can be successfully used at the space center. These composite materials should not be used where they will be exposed to the hot exhaust plume/cloud of the launch vehicle during the liftoff, and caution should be taken in their use in areas where electrostatic discharge and hypergolic propellant compatibility are primary concerns.

  19. Benefit evaluation of space processing of biological materials

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A rational analytical basis for the evaluation of potential benefits of space processing of biological materials is described. A preliminary evaluation of three candidate space processed biological materials was accomplished. Materials investigated were human lymphocytes, urokinase, and Beta cells. Separation of lymphocyte groups was considered in order to improve the matching of donors and recipients for kidney transplantation, while urokinase was examined in regard to treatment of thromboembolic diseases. Separation of Beta cells was studied since it could provide a highly effective means for the treatment of juvenile-onset diabetes.

  20. Evaluation of ceramic filter material, selection for application

    SciTech Connect

    Alvin, M.A.; Tressler, R.E.; Lippert, T.E.; Diaz, E.S.

    1993-09-01

    Field testing in several of the Westinghouse Advanced Particulate Filtration (APF) systems has indicated that the oxide-based materials are more susceptible to thermal shock which results from system transients (i.e., combustion of char or reducing gases; system startup/turbine transients). The current clay bonded silicon carbide filter materials have a higher thermal shock resistance, but appear to be more susceptible to high temperature creep, as well as to changes that occur within the binder phase(s). Strength has frequently been used to assess what effects advanced coal fired process systems have on the stability and projected life of the various porous ceramic filter materials (Tables 1 and 2). Based on the numerous phase changes that occur, and the influence of pulse cleaning on the thermal fatigue characteristics of both the alumina/mullite and clay bonded silicon carbide filter materials, alternate material properties as thermal conductivity, thermal coefficient of expansion, elastic modulus, fracture toughness, and emissivity as a function of thermal/chemical aging are now being considered as critical factors for projecting filter durability and operating life. Table 3 provides a summary of the as-manufactured material properties for the alumina/mullite and clay bonded silicon carbide filter materials which have been used in the Westinghouse`s APF systems. Effort is currently being directed to determine how these properties change during thermal aging of the filters in various subpilot and pilot plant systems.

  1. Aging commuter aeroplanes: Fatigue evaluation and control methods

    NASA Technical Reports Server (NTRS)

    Emmerson, A. J.

    1992-01-01

    The loss of reliability in aircraft is caused by two broad classes of problems. There are those problems which are self evident and hazardous rather than catastrophic. These are the problem areas where characteristically there have been multiple overhauls, repairs, and replacements, and where aging really means the results of repair ineffectiveness that accumulates. The other class of the problem is the insidious and potentially catastrophic class. It includes the progressive deterioration of items that are not maintained, and often cannot be maintained because the deterioration cannot be seen. It includes the loss of physical properties in adhesives and other organic compounds, corrosion, and the response of repeated loads. Dealt with here is a currently unnecessarily troublesome aspect of that response. Although we must remain concerned about those types of aircraft which have been certified under a design standard or operational rule which embodies the elementary fail-safe concept and which have not been subjected to a subsequent structural audit, the focus here is on types of aircraft for which fatigue and damage tolerance evaluation was not required as a condition of certification.

  2. Instrumental evaluation of anti-aging effects of cosmetic formulations containing palmitoyl peptides, Silybum marianum seed oil, vitamin E and other functional ingredients on aged human skin

    PubMed Central

    Hahn, Hyung Jin; Jung, Ho Jung; Schrammek-Drusios, Med Christine; Lee, Sung Nae; Kim, Ji-Hyun; Kwon, Seung Bin; An, In-Sook; An, Sungkwan; Ahn, Kyu Joong

    2016-01-01

    Anti-aging cosmetics are widely used for improving signs of aged skin such as skin wrinkles, decreased elasticity, low dermal density and yellow skin tone. The present study evaluated the effects of cosmetic formulations, eye cream and facial cream, containing palmitoyl peptides, Silybum marianum (S. marianum) seed oil, vitamin E and other functional ingredients on the improvement of facial wrinkles, elasticity, dermal density and skin tone after 4 weeks period of application on aged human skin. Healthy volunteers (n=20) with aged skin were recruited to apply the test materials facially twice per day for 4 weeks. Skin wrinkles, elasticity, dermal density and skin tone were measured instrumentally for assessing the improvement of skin aging. All the measurements were conducted prior to the application of test materials and at 2 and 4 weeks of treatment. Crow's feet wrinkles were decreased 5.97% after 2 weeks of test material application and 14.07% after 4 weeks of application in comparison of pre-application. Skin elasticity was increased 6.81% after 2 weeks and 8.79% after 4 weeks. Dermal density was increased 16.74% after 2 weeks and 27.63% after 4 weeks. With the L* value indicating skin brightness and the a* value indicating erythema (redness), the results showed that brightness was increased 1.70% after 2 weeks and 2.14% after 4 weeks, and erythema was decreased 10.45% after 2 weeks and 22.39% after 4 weeks. Hence, the test materials appear to exert some degree of anti-aging effects on aged human skin. There were no abnormal skin responses from the participants during the trial period. We conclude that the facial and eye cream containing palmitoyl peptides and S. marianum seed oil, vitamin E and other ingredients have effects on the improvement of facial wrinkles, elasticity, dermal density and skin tone. PMID:27446338

  3. 230Th-234U Model-Ages of Some Uranium Standard Reference Materials

    SciTech Connect

    Williams, R W; Gaffney, A M; Kristo, M J; Hutcheon, I D

    2009-05-28

    The 'age' of a sample of uranium is an important aspect of a nuclear forensic investigation and of the attribution of the material to its source. To the extent that the sample obeys the standard rules of radiochronometry, then the production ages of even very recent material can be determined using the {sup 230}Th-{sup 234}U chronometer. These standard rules may be summarized as (a) the daughter/parent ratio at time=zero must be known, and (b) there has been no daughter/parent fractionation since production. For most samples of uranium, the 'ages' determined using this chronometer are semantically 'model-ages' because (a) some assumption of the initial {sup 230}Th content in the sample is required and (b) closed-system behavior is assumed. The uranium standard reference materials originally prepared and distributed by the former US National Bureau of Standards and now distributed by New Brunswick Laboratory as certified reference materials (NBS SRM = NBL CRM) are good candidates for samples where both rules are met. The U isotopic standards have known purification and production dates, and closed-system behavior in the solid form (U{sub 3}O{sub 8}) may be assumed with confidence. We present here {sup 230}Th-{sup 234}U model-ages for several of these standards, determined by isotope dilution mass spectrometry using a multicollector ICP-MS, and compare these ages with their known production history.

  4. Metallurgical evaluation of factors influencing the ductility of aged T-111

    NASA Technical Reports Server (NTRS)

    Gold, R. E.

    1972-01-01

    The metallurgical factors influencing the ductility of T-111 (Ta-8W-2Hf) alloy following long-time exposures of GTA welds and tubing in the temperature range 982 C (1800 F) through 1316 C (2400 F) were evaluated by means of scanning and transmission electron microscopy, Auger electron emission spectroscopy, and optical metallographic procedures. No classical aging response occurs in the alloy over the temperature range studied. The ductility impairment implied by previous investigations is not the result of microstructural response of the alloy to thermal exposures. Intergranular failure in the GTA sheet welds appears the result of random contamination by silicon, potassium, and/or fluorine at the grain boundaries of the fusion zones. Exposure to lithium at high temperatures had no adverse effects on the ductility of T-111 tubing. These materials were, however, sensitive to post-age handling and testing procedures.

  5. Economic evaluation of closure cap barrier materials study

    SciTech Connect

    Serrato, M.G.; Bhutani, J.S.; Mead, S.M.

    1993-09-01

    Volume II of the Economic Evaluation of the Closure Cap Barrier Materials, Revision I contains detailed cost estimates for closure cap barrier materials. The cost estimates incorporate the life cycle costs for a generic hazardous waste seepage basin closure cap under the RCRA Post Closure Period of thirty years. The economic evaluation assessed six barrier material categories. Each of these categories consists of several composite cover system configurations, which were used to develop individual cost estimates. The information contained in this report is not intended to be used as a cost estimating manual. This information provides the decision makers with the ability to screen barrier materials, cover system configurations, and identify cost-effective materials for further consideration.

  6. Job Characteristics, Core Self-Evaluations, and Job Satisfaction: What's Age Got to Do with It?

    ERIC Educational Resources Information Center

    Besen, Elyssa; Matz-Costa, Christina; Brown, Melissa; Smyer, Michael A.; Pitt-Catsouphes, Martha

    2013-01-01

    There is a well-established relationship between age and job satisfaction. To date, there is little research about how many well-known predictors of job satisfaction, specifically job characteristics and core self-evaluations, may vary with age. Using a multi-worksite sample of 1,873 employed adults aged 17 to 81, this study evaluated the extent…

  7. AGING PERFORMANCE OF VITON GLT O-RINGS IN RADIOACTIVE MATERIAL PACKAGES

    SciTech Connect

    Skidmore, E; Kerry Dunn, K; Elizabeth Hoffman, E; Elise Fox, E; Kathryn Counts, K

    2007-05-07

    Radioactive material packages used for transportation of plutonium-bearing materials often contain multiple O-ring seals for containment. Packages such as the Model 9975 are also being used for interim storage of Pu-bearing materials at the Savannah River Site (SRS). One of the seal materials used in such packages is Viton{reg_sign} GLT fluoroelastomer. The aging behavior of containment vessel O-rings based on Viton{reg_sign} GLT at long-term containment term storage conditions is being characterized to assess its performance in such applications. This paper summarizes the program and test results to date.

  8. The aging of wire chambers filled with dimethyl ether: wire and construction materials and freon impurities

    NASA Astrophysics Data System (ADS)

    Jibaly, Mohammed; Majewski, Stan; Chrusch, Peter; Wojcik, Randolph; Sauli, Fabio; Gaudaen, Jan

    1989-11-01

    This is a complete summary of our study of the aging of different types of wire chambers, with a variety of construction materials and wires, filled with dimethyl ether (DME) of varying degrees of purity. The resistive Nicotin and Stablohm wires were corroded by DME, producing fast aging. The moderately resistive stainless steel wires were able to withstand extended irradiation (up to 1 C/cm) in high-purity DME without any apparent damage; and gold-plated tungsten and molybdenum wires exhibited a comparable behavior. Many construction materials were tested and recommendations are thus reached as to what kinds of materials are safe in building DME-operated wire chambers. Among many different Freon and hydrocarbon impurities detected in DME by means of gas chromatography (GC), Freon-11 was found to be mostly responsible for the aging, even with noncorrosive stainless steel or gold-plated wires. The availability and feasibility of obtaining Freon-free DME is reported as well.

  9. Objective evaluation of insert material for diabetic and athletic footwear.

    PubMed

    Brodsky, J W; Kourosh, S; Stills, M; Mooney, V

    1988-12-01

    Five of the most commonly used materials for shoe inserts (soft Plastazote, medium Pelite, PPT, Spenco, and Sorbothane) were objectively evaluated in the laboratory to characterize their behavior in the following three specific functions that correspond to clinical use: (1) the effect on the materials of repeated compression. (2) the effect of a combination of repetitive shear and compression. (3) the force-distribution (force-attenuation) properties of these materials, both when new and after repeated compression. The last function represents a model for relief of pressure beneath plantar bony prominences, a topic of special concern for the insensitive foot. All materials were effective in reducing transmitted force over the simulated bony prominence with a rank order of effectiveness. Other factors considered were: amount and rate of permanent deformation offset by considerations of enhanced moldability when comparing the neoprene and urethane materials with the polyethylene foams. The ideal insert represents a combination of material to achieve both durability and moldability. PMID:3229697

  10. Material Aging and Degradation Detection and Remaining Life Assessment for Plant Life Management

    SciTech Connect

    Ramuhalli, Pradeep; Henager, Charles H.; Griffin, Jeffrey W.; Meyer, Ryan M.; Coble, Jamie B.; Pitman, Stan G.; Bond, Leonard J.

    2012-12-31

    One of the major factors that may impact long term operations is structural material degradation, Detecting materials degradation, estimating the remaining useful life (RUL) of the component, and determining approaches to mitigating the degradation are important from the perspective of long term operations. In this study, multiple nondestructive measurement and monitoring methods were evaluated for their ability to assess the material degradation state. Metrics quantifying the level of damage from these measurements were defined, and evaluated for their ability to provide estimates of remaining life of the component. An example of estimating the RUL from nondestructive measurements of material degradation condition is provided.

  11. Evaluation and Validation of Organic Materials for Advanced Stirling Convertors (ASCs): Overview

    NASA Technical Reports Server (NTRS)

    Shin, Euy-Sik Eugene

    2015-01-01

    Various organic materials are used as essential parts in Stirling Convertors for their unique properties and functionalities such as bonding, potting, sealing, thread locking, insulation, and lubrication. More efficient Advanced Stirling Convertors (ASC) are being developed for future space applications especially with a long mission cycle, sometimes up to 17 years, such as deep space exploration or lunar surface power or Mars rovers, and others. Thus, performance, durability, and reliability of those organics should be critically evaluated in every possible material-process-fabrication-service environment relations based on their mission specifications. In general, thermal stability, radiation hardness, outgassing, and material compatibility of the selected organics have been systematically evaluated while their process and fabrication conditions and procedures were being optimized. Service environment-simulated long term aging tests up to 4 years were performed as a function of temperature for durability assessment of the most critical organic material systems.

  12. Low earth orbital atomic oxygen simulation for materials durability evaluation

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Rutledge, Sharon K.

    1989-01-01

    The erosion yields of numerous materials have been evaluated in low earth orbital space tests. There appears to be three classes of materials: materials of high erosion yield which include most of the hydrocarbon organic materials; materials which either do not react with atomic oxygen or form self-protecting oxides which allow the underlying material to appear durable to atomic oxygen, and materials with low but nonnegligeable erosion yields, such as fluoropolymers. A NASA atomic oxygen effects test program has been established to utilize collective data from a multitude of simulation facilities to promote an understanding of mechanism and erosion yield dependencies. Atomic oxygen protective coatings for Kapton polymide solar array blankets, fiberglass-epoxy composite mast structures, and solar dynamic power system concentrator surfaces have been identified and evaluated under atomic oxygen exposure in RF plasma asher laboratory tests. The control of defect density in protective coatings appears to be the key to the assurance of long-term protection of oxidizable materials in low earth orbit.

  13. Materials and Nondestructive Evaluation Laboratoriers: User Test Planning Guide

    NASA Technical Reports Server (NTRS)

    Schaschl, Leslie

    2011-01-01

    The Materials and Nondestructive Evaluation Laboratory process, milestones and inputs are unknowns to first-time users. The Materials and Nondestructive Evaluation Laboratory Planning Guide aids in establishing expectations for both NASA and non- NASA facility customers. The potential audience for this guide includes both internal and commercial spaceflight hardware developers. It is intended to assist their project engineering personnel in materials analysis planning and execution. Material covered includes a roadmap of the analysis process, roles and responsibilities of facility and user, major milestones, facility capabilities, and inputs required by the facility. Samples of deliverables, products, and inputs necessary to define scope of analysis, cost, and schedule are included as an appendix to the guide.

  14. Recyclability Evaluation Method Considering Material Combination and Degradation

    NASA Astrophysics Data System (ADS)

    Oyasato, Naohiko; Kobayashi, Hideki

    A new method of recyclability evaluation is proposed. The recyclability of a product is given by summing up recyclability of all units to which the product is manually disassembled. The recyclability of a unit is calculated if all names and amounts of materials of which the unit is composed are known. The recyclability of a disassembled unit consisting of multiple materials is judged on the grounds of removability of impurities, miscibility and marketability of polymer blends. Recyclability of a long-lifetime product can be estimated from recyclability of units, which are modeled as probabilistically distributed degradation of materials. The proposed method is applied to recyclability evaluation for a refrigerator with several scenarios of disassembly levels. The practical disassembly scenarios limit the maximum recyclability rate of the product. Therefore, recyclability rates calculated based on the proposed method are considerably lower than those of the recyclable materials of which the product consisted.

  15. Methodology for Evaluating Raw Material Changes to RSRM Elastomeric Insulation Materials

    NASA Technical Reports Server (NTRS)

    Mildenhall, Scott D.; McCool, Alex (Technical Monitor)

    2001-01-01

    The Reusable Solid Rocket Motor (RSRM) uses asbestos and silicon dioxide filled acrylonitrile butadiene rubber (AS-NBR) as the primary internal insulation to protect the case from heat. During the course of the RSRM Program, several changes have been made to the raw materials and processing of the AS-NBR elastomeric insulation material. These changes have been primarily caused by raw materials becoming obsolete. In addition, some process changes have been implemented that were deemed necessary to improve the quality and consistency of the AS-NBR insulation material. Each change has been evaluated using unique test efforts customized to determine the potential impacts of the specific raw material or process change. Following the evaluations, the various raw material and process changes were successfully implemented with no detectable effect on the performance of the AS-NBR insulation. This paper will discuss some of the raw material and process changes evaluated, the methodology used in designing the unique test plans, and the general evaluation results. A summary of the change history of RSRM AS-NBR internal insulation is also presented.

  16. 20 CFR 416.924b - Age as a factor of evaluation in the sequential evaluation process for children.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... chronological age. When we evaluate the development or linear growth of a child born prematurely, we may use a... infants. We generally use chronological age (that is, a child's age based on birth date) when we decide... children until the child's prematurity is no longer a relevant factor; generally no later than...

  17. 20 CFR 416.924b - Age as a factor of evaluation in the sequential evaluation process for children.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... chronological age. When we evaluate the development or linear growth of a child born prematurely, we may use a... infants. We generally use chronological age (that is, a child's age based on birth date) when we decide... children until the child's prematurity is no longer a relevant factor; generally no later than...

  18. 20 CFR 416.924b - Age as a factor of evaluation in the sequential evaluation process for children.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... chronological age. When we evaluate the development or linear growth of a child born prematurely, we may use a... infants. We generally use chronological age (that is, a child's age based on birth date) when we decide... children until the child's prematurity is no longer a relevant factor; generally no later than...

  19. Evaluation of Generalized Performance across Materials When Using Video Technology by Students with Autism Spectrum Disorder and Moderate Intellectual Disability

    ERIC Educational Resources Information Center

    Mechling, Linda C.; Ayres, Kevin M.; Foster, Ashley L.; Bryant, Kathryn J.

    2015-01-01

    The purpose of this study was to evaluate the ability of four high school-aged students with a diagnosis of autism spectrum disorder and moderate intellectual disability to generalize performance of skills when using materials different from those presented through video models. An adapted alternating treatments design was used to evaluate student…

  20. Weightless Environment Training Facility (WETF) materials coating evaluation, volume 1

    NASA Technical Reports Server (NTRS)

    1995-01-01

    The Weightless Environment Training Facility Material Coating Evaluation project has included preparing, coating, testing, and evaluating 800 test panels of three differing substrates. Ten selected coating systems were evaluated in six separate exposure environments and subject to three tests for physical properties. Substrate materials were identified, the manner of surface preparation described, and exposure environments defined. Exposure environments included immersion exposure, cyclic exposure, and field exposure. Cyclic exposures, specifically QUV-Weatherometer and the KTA Envirotest were found to be the most agressive of the environments included in the study when all three evaluation criteria are considered. This was found to result primarily from chalking of the coatings under ultraviolet (UV) light exposure. Volumes 2 and 3 hold the 5 appendices to this report.

  1. An Evaluation of Techroll Seal Flexible Joint Material

    NASA Technical Reports Server (NTRS)

    Hall, W. B.

    1983-01-01

    This study evaluated the materials utilized in the flexible joint for possible failure modes. Studies undertaken included effect of temperature on the strength of the system, effect of fatigue on the strength of the system, thermogravimetric analysis, thermochemical analysis, differential scanning calorimeter analysis, dynamic mechanical analysis, and peel test. These studies indicate that if the joint failed due to a materials deficiency, the most likely mode was excessive temperature in the joint. In addition, the joint material is susceptible to fatigue damage which could have been a contributing factor.

  2. Weightless Environment Training Facility (WETF) materials coating evaluation, volume 3

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This volume consists of Appendices C, D, E, and F to the report on the Weightless Environment Training Facility Materials Coating Evaluation project. The project selected 10 coating systems to be evaluated in six separate exposure environments, and subject to three tests for physical properties. Appendix C is the photographic appendix of the test panels. Appendix D details methods and procedures. Appendix E lists application equipment costs. Appendix F is a compilation of the solicitation of the candidate coating systems.

  3. Environmental Evaluation of Building Materials of 5 Slovak Buildings

    NASA Astrophysics Data System (ADS)

    Porhincak, Milan; Estokova, Adriana

    2013-11-01

    Building activity has recently led to the deterioration of environment and has become unsustainable. Several strategies have been introduced in order to minimize consumption of energy and resulting CO2 emissions having their origin in the operational phase. But also other stages of Life Cycle should are important to identify the overall environmental impact of construction sector. In this paper 5 similar Slovak buildings (family houses) were analyzed in terms of environmental performance of building materials used for their structures. Evaluation included the weight of used materials, embodied energy and embodied CO2 and SO2 emissions. Analysis has proven that the selection of building materials is an important factor which influences the environmental profile. Findings of the case study indicated that materials like concrete, ceramic or thermal insulation materials based on polystyrene and mineral wool are ones with the most negative environmental impact.

  4. Evaluation of heat- and blast-protection materials

    NASA Technical Reports Server (NTRS)

    Morrison, J. D.; Lockhart, B. J.

    1971-01-01

    A program was initiated at the Kennedy Space Center in December 1967 and conducted through December 1969 to evaluate the performance of heat- and blast-protection materials for ground support equipment used during the Apollo/Saturn launches. Materials believed to be generally suitable for heat and blast protection were subjected to launch-exposure tests. Tests were made during the Apollo/Saturn 502, 503, and 505 launches. Tests were also made in a local laboratory, as an alternative to the restrictive requirements of launch-exposure tests, to determine the effects of torch-flame exposure on ablative materials. Five materials were found to be satisfactory in all major test categories. It was determined that torch-flame tests can probably be utilized as an acceptable substitute for the booster-engine-exhaust exposure tests for basic screening of candidate materials.

  5. Age, Sex and Socioeconomic Background as Factors in Preschool Children's Preference for Play Materials.

    ERIC Educational Resources Information Center

    Bogdanoff, Ruth F.; Peebles, Linda M.

    A total of 103 preschool children of lower and middle socioeconomic status families were observed in three preschool programs during 15 standardized free play periods for the purpose of investigating preschool children's preferences for different types of traditionally used play materials. The influence of age, sex, and socioeconomic status (SES)…

  6. Disseminating the Positively Aging[R] Teaching Materials: Results of a Controlled Trial

    ERIC Educational Resources Information Center

    Lichtenstein, Michael J.; Pruski, Linda A.; Marshall, Carolyn E.; Blalock, Cheryl L.; Liu, Yan; Plaetke, Rosemarie

    2005-01-01

    This study tested the effectiveness of 2 dissemination methods for the Positively Aging teaching materials. In San Antonio, Texas, 4 middle schools participated in a 3-year controlled trial of dissemination via distance electronic support alone (control) compared to distance electronic support plus in-school support from study staff…

  7. The evaluation of two radiographic methods for age determination of children in an Indian population.

    PubMed

    Rai, B

    2008-12-01

    The aim of the present study was to evaluate the applicability of the methods proposed by Nolla and Nicodemo for estimation of dental age and its correction with chronological age. Orthopantograms of 413 patients, aged 6-16 year (70-195 months) were selected to estimate the correlation between dental and chronological age. With both the Nolla and Nicodemo methods, the estimated age was lower than compared to chronological age except for the Nolla method in girls. There were significant correlations between chronological and estimated dental age (by Nolla and Nicodemo methods) in both genders. PMID:22717786

  8. Long-term thermal aging of 2 graphite-polyimide composite materials

    NASA Technical Reports Server (NTRS)

    Nelson, J. B.

    1984-01-01

    Two graphite/polyimide composite materials were aged in circulating air ovens at temperatures 204 C, 232 C, 260 C, and 288 C for various times up to 25000 hours. The composites were: (1) Celanese Celion 6000 graphite fiber and PMR-15 polyimide resin (Celion/PMR-15) and (2) Celion 6000 graphite fiber and LARC-160 polyimide resin (Celion/LARC-160). Three unidirectional specimen geometries were studied: short beam shear (SBS) specimens, flexure specimens, and 153 mm square panels. The interior regions of the square panels exhibited only minor property degradation. The individually aged SBS and flexure specimens exhibited large reductions in strengths after aging. Both laminate materials cracked and degraded preferentially at the specimen edge perpendicular to the fibers.

  9. Evaluation of docket files for terminated source material licenses

    SciTech Connect

    Holoway, C.F.; Lantz, P.M.; Dickson, H.W.

    1980-01-01

    Terminated source material licenses from docket files of the Nuclear Regulatory Commission (NRC) have been evaluated with respect to the potential for residual radiological health problems. Some 8,275 source material docket files were sent from the Federal Repository for NRC to Oak Ridge National Laboratory for evaluation. An NRC printed inventory of terminated source material licenses was sent separately and input to a computer file for ready access. The files were inventoried and a methodology was developed for evaluation of these files. The methodology included development of a combined analysis/computer input form. Pertinent data were abstracted from each file, placed on this form, and entered into a separate private-access computer file. At the same time, analysts using screening criteria made a preliminary categorization of the files. All files categorized initially as potential radiological health problems were reviewed in depth to arrive at a final categorization. Criteria for judgment included quantities of source material (uranium and/or thorium) going to and leaving the site in question during the operational lifetime of the site, disposition of source material not leaving the site, types of operations carried on at the site during the licensed period, and the physicochemical forms of products and wastes involved. In the final analysis, 193 dockets were identified as having potential for residual radiological health problems.

  10. Evaluation of SRM flex bearing materials and processes

    NASA Technical Reports Server (NTRS)

    Wood, T. E.

    1980-01-01

    Tensile, peel, and shear testing was performed on combinations of primers, adhesives, tycements and rubber compounds cured at various times and temperatures. The materials used in the fabrication of the solid rocket motor flex bearing as well as in other systems were evaluated. A compatibility study between adhesives and tycements was initiated. The flex bearing mold design was reviewed by our tooling experts.

  11. Safety of Disposable Diaper Materials: Extensive Evaluations Validate Use.

    PubMed

    Dey, Swatee; Helmes, C Tucker; White, Jeffrey C; Zhou, Shaoying

    2014-06-24

    Disposable diapers are primarily composed of polymers, such as cellulose, polypropylene, polyester, and polyethylene, which are biologically inert and not bioavailable. They are used in clothes, fabrics, personal hygiene products, and other materials that are commonly in contact with the skin. Each component used throughout the production process must undergo rigorous safety evaluations and assessments and are proven to be well tolerated and safe for their intended uses. No materials are incorporated into a diaper until their safety is confirmed through robust assessments, and additional factors are integrated into the process to compensate for the uncertainty associated with extrapolating toxicity data. After a thorough assessment of the materials and final product, extensive skin compatibility evaluations are conducted as appropriate. This rigorous safety process provides reassurance that consumers can rely on the safety of these diapers. PMID:24961774

  12. Materials Development and Evaluation of Selective Laser Sintering Manufacturing Applications

    SciTech Connect

    Smith, Peter F.; Mitchell, Russell R.

    1997-01-15

    This report summarizes the FY96 accomplishments for CRADA No. LA95C10254, "Materials Development and Evaluation of Laser Sintering Manufacturing Applications". To research the potential for processing additional materials using DTM Corporations Selective Laser Sintering rapid prototyping technology and evaluate the capability for rapid manufacturing applications, the following materials were processed experimentally using the Sinterstation 2000 platform; Linear Low Density Polyethylene thermoplastic; Polypropylene thermoplastic; Polysulfone thermoplastic; Polymethylpentene (TPX) thermoplastic; Carbon microsphere filled nylon 11; "APO-BMI" Apocure bismaleimide thermoset polyimide glass m.icrosphere filled and carbon microsphere filled formulations; and 900-24 physical properties mock for plastic bonded TATB high explosive These materials have been successfully processed to a "proof of concept" level or better (with the exception of No. 7). While none of these materials have been introduced as a standard product as of this date, the potential to do so is viable. Present status of materials processing efforts is presented in Section A 2.0. Some recent efforts in manufacturing applications is discussed in Section A 4.0.

  13. Evaluation of bone remodeling in regard to the age of scaphoid non-unions

    PubMed Central

    Rein, Susanne; Hanisch, Uwe; Schaller, Hans-Eberhard; Zwipp, Hans; Rammelt, Stefan; Weindel, Stefan

    2016-01-01

    AIM: To analyse bone remodeling in regard to the age of scaphoid non-unions (SNU) with immunohistochemistry. METHODS: Thirty-six patients with symptomatic SNU underwent surgery with resection of the pseudarthrosis. The resected material was evaluated histologically after staining with hematoxylin-eosin (HE), tartrate resistant acid phosphatase (TRAP), CD 68, osteocalcin (OC) and osteopontin (OP). Histological examination was performed in a blinded fashion. RESULTS: The number of multinuclear osteoclasts in the TRAP-staining correlated with the age of the SNU and was significantly higher in younger SNU (P = 0.034; r = 0.75). A higher number of OP-immunoreactive osteoblasts significantly correlated with a higher number of OC-immunoreactive osteoblasts (P = 0.001; r = 0.55). Furthermore, a greater number of OP-immunoreactive osteoblasts correlated significantly with a higher number of OP-immunoreactive multinuclear osteoclasts (P = 0.008; r = 0.43). SNU older than 6 mo showed a significant decrease of the number of fibroblasts (P = 0.04). Smoking and the age of the patients had no influence on bone remodeling in SNU. CONCLUSION: Multinuclear osteoclasts showed a significant decrease in relation to the age of SNU. However, most of the immunhistochemical findings of bone remodeling do not correlate with the age of the SNU. This indicates a permanent imbalance of bone formation and resorption as indicated by a concurrent increase in both osteoblast and osteoclast numbers. A clear histological differentiation into phases of bone remodeling in SNU is not possible. PMID:27458552

  14. Separator Materials Used in Secondary Alkaline Batteries Characterized and Evaluated

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Nickel-cadmium (Ni/Cd) and nickel-hydrogen (Ni/H2) secondary alkaline batteries are vital to aerospace applications. Battery performance and cycle life are significantly affected by the type of separators used in those batteries. A team from NASA Lewis Research Center's Electrochemical Technology Branch developed standardized testing procedures to characterize and evaluate new and existing separator materials to improve performance and cycle life of secondary alkaline batteries. Battery separators must function as good electronic insulators and as efficient electrolyte reservoirs. At present, new types of organic and inorganic separator materials are being developed for Ni/Cd and Ni/H2 batteries. The separator material previously used in the NASA standard Ni/Cd was Pellon 2505, a 100-percent nylon-6 polymer that must be treated with zinc chloride (ZnCl2) to bond the fibers. Because of stricter Environmental Protection Agency regulation of ZnCl2 emissions, the battery community has been searching for new separators to replace Pellon 2505. As of today, two candidate separator materials have been identified; however, neither of the two materials have performed as well as Pellon 2505. The separator test procedures that were devised at Lewis are being implemented to expedite the search for new battery separators. The new test procedures, which are being carried out in the Separator Laboratory at Lewis, have been designed to guarantee accurate evaluations of the properties that are critical for sustaining proper battery operation. These properties include physical and chemical stability, chemical purity, gas permeability, electrolyte retention and distribution, uniformity, porosity, and area resistivity. A manual containing a detailed description of 12 separator test procedures has been drafted and will be used by the battery community to evaluate candidate separator materials for specific applications. These standardized procedures will allow for consistent, uniform

  15. Characterization of aging in organic materials on atomic-, meso- and macro-length scales by {sup 13}C NMR spectroscopy

    SciTech Connect

    Assink, R.A.; Jamison, G.M.; Alam, T.M.; Gillen, K.T.

    1997-10-01

    A fundamental understanding of aging in an organic material requires that one understand how aging affects the chemical structure of a material, and how these chemical changes are related to the material`s macroscopic properties. This level of understanding is usually achieved by examining the material on a variety of length scales ranging from atomic to meso-scale to macroscopic. The authors are developing and applying several {sup 13}C nuclear magnetic resonance (NMR) spectroscopy experiments to characterize the aging process of organic materials over a broad range of length scales. Examples of studies which range from atomic to macroscopic will be presented.

  16. THIRD STATUS REPORT: TESTING OF AGED SOFTWOOD FIBERBOARD MATERIAL FOR THE 9975 SHIPPING PACKAGE

    SciTech Connect

    Daugherty, W.

    2011-12-13

    Samples have been prepared from a 9975 lower fiberboard subassembly fabricated from softwood fiberboard. Physical, mechanical and thermal properties have been measured following varying periods of conditioning in each of several environments. These tests have been conducted in the same manner as previous testing on cane fiberboard samples. Overall, similar aging trends are observed for softwood and cane fiberboard samples, with a few differences. There is no clear trend thus far to indicate one material ages in a manner significantly different from the other material. Some softwood fiberboard properties degrade faster in some environments, while cane fiberboard degrades faster with regards to other properties and environments. Given the limited aging time accumulated to date in the elevated humidity environments, it is recommended that aging and testing of softwood fiberboard continue for another year. Post-conditioning data have been measured on samples from a single softwood fiberboard assembly, and baseline data are also available from a limited number of vendor-provided samples. This provides minimal information on the possible sample-to-sample variation exhibited by softwood fiberboard. Data to date are generally consistent with the range seen in cane fiberboard, but some portions of the data trends are skewed toward the lower end of that range. Further understanding of the variability of softwood fiberboard properties will require testing of additional material.

  17. 20 CFR 408.413 - How do we evaluate the evidence of age you give us?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false How do we evaluate the evidence of age you give us? 408.413 Section 408.413 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II VETERANS Evidence Requirements Age § 408.413 How do we evaluate the...

  18. 20 CFR 408.413 - How do we evaluate the evidence of age you give us?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false How do we evaluate the evidence of age you give us? 408.413 Section 408.413 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II VETERANS Evidence Requirements Age § 408.413 How do we evaluate the...

  19. 20 CFR 408.413 - How do we evaluate the evidence of age you give us?

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false How do we evaluate the evidence of age you give us? 408.413 Section 408.413 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II VETERANS Evidence Requirements Age § 408.413 How do we evaluate the...

  20. 20 CFR 408.413 - How do we evaluate the evidence of age you give us?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false How do we evaluate the evidence of age you give us? 408.413 Section 408.413 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II VETERANS Evidence Requirements Age § 408.413 How do we evaluate the...

  1. 20 CFR 408.413 - How do we evaluate the evidence of age you give us?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false How do we evaluate the evidence of age you give us? 408.413 Section 408.413 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II VETERANS Evidence Requirements Age § 408.413 How do we evaluate the...

  2. Ageing of organic electrical insulating materials due to radiation—III. Dielectric properties of a cycloaliphatic epoxy resin: Effect of irradiation environmental conditions and dose rate

    NASA Astrophysics Data System (ADS)

    Spadaro, G.; Calderaro, E.; Schifani, R.; Rizzo, G.

    The effect of dose rate under different environmental conditions on a cycloaliphatic epoxy resin is considered. In particular dielectric measurements were performed. The dose rate is an interesting parameter on evaluating the behaviour of insulating materials in real operating conditions by means of accelerated ageing laboratory tests.

  3. Post STS-134 Evaluation of Main Flame Deflector Witness Materials

    NASA Technical Reports Server (NTRS)

    Long, Victoria

    2011-01-01

    NASA and USA design engineers submitted witness materials from the solid rocket booster (SRB) main flame deflector for evaluation after the launch of STS-134. The following items were submitted for analysis: 1018 steel witness rods 304 stainless steel caps, tungsten pistons, and A-286 piston sleeves. All of the items were photographed in order to document their condition after the launch of STS-134. All of the items were dimensionally measured in order to determine the amount of material lost during launch. Microstructural changes were observed in the 1018 witness rod metallographic samples due to the heat of the launch

  4. Post STS-135 Evaluation of Main Flame Deflector Witness Materials

    NASA Technical Reports Server (NTRS)

    Long, Victoria

    2011-01-01

    NASA and USA design engineers submitted witness materials from the solid rocket booster (SRB) main flame deflector for evaluation after the launch of STS-135. The following items were submitted for analysis: HY-80 steel witnes rods, 304 sta inles steel caps, and tungsten pistons. All of the items were photographed in order to document their condition after the launch of STS-135. The submitted samples were dimensionally measured in order to determine the amount of material lost during launch. Microstructural changes were observed in the HY-80 witness rod metallographic samples due to the heat of the launch.

  5. Gas turbine materials evaluation program utilizing coal derived gaseous fuel

    NASA Astrophysics Data System (ADS)

    Williams, M. L.; Yates, C. C.; Manning, G. B.; Peterson, R. R.

    1981-03-01

    A gas turbine materials evaluation test facility under the sponsorship of the U.S. Department of Energy is described. The objective of the mobile test facility is to obtain dynamic and static test data on the erosion/corrosion characteristics of materials exposed to the hot products of the combustion of coal-derived fuels. The engine being utilized for the tests is the WR 24-7 aircraft turbojet unit reconfigurated to burn coke oven gas. Approximately 100 hours of engine operating time have been logged to date.

  6. Potential techniques for non-destructive evaluation of cable materials

    NASA Astrophysics Data System (ADS)

    Gillen, Kenneth T.; Clough, Roger L.; Mattson, Bengt; Stenberg, Bengt; Oestman, Erik

    This paper describes the connection between mechanical degradation of common cable materials, in radiation and elevated temperature environments, and density increases caused by the oxidation which leads to this degradation. Two techniques based on density changes are suggested as potential non-destructive evaluation (NDE) procedures which may be applicable to monitoring the mechanical condition of cable materials in power plant environments. The first technique is direct measurement of density changes, via a density gradient column, using small shavings removed from the surface of cable jackets at selected locations. The second technique is computed X-ray tomography, utilizing a portable scanning device.

  7. Evaluating and treating school-aged children who stutter.

    PubMed

    Yaruss, J Scott

    2010-11-01

    School-based speech-language pathologists are often called upon to treat children who stutter, though many clinicians have reported that they feel uncomfortable working with this population. Fortunately, there is much that speech-language pathologists can do to help children who stutter speak more easily and minimize the adverse impact of stuttering in both academic and social settings. The purpose of this article is to provide clinicians with a guide to some of the key issues they should consider when working with school-aged children who stutter. The goal is to encourage clinicians to develop a better understanding of how stuttering can affect school-aged children, how the adverse effects of the disorder can be documented so children can be qualified for treatment, and, ultimately, how the negative consequences of stuttering can be minimized through a comprehensive approach to treatment. PMID:21080298

  8. Sixth Status Report: Testing of Aged Softwood Fiberboard Material for the 9975 Shipping Package

    SciTech Connect

    Daugherty, W.

    2015-03-31

    Samples have been prepared from several 9975 lower fiberboard subassemblies fabricated from softwood fiberboard. Physical, mechanical and thermal properties have been measured following varying periods of conditioning in each of several environments. These tests have been conducted in the same manner as previous testing on cane fiberboard samples. Overall, similar aging trends are observed for softwood and cane fiberboard samples, with a few differences. Some softwood fiberboard properties tend to degrade faster in some environments, while some cane fiberboard properties degrade faster in the two most aggressive environments. As a result, it is premature to assume both materials will age at the same rates, and the preliminary aging models developed for cane fiberboard might not apply to softwood fiberboard. However, it is expected that both cane and softwood fiberboard assemblies will perform satisfactorily in conforming packages stored in a typical KAC storage environment for up to 15 years. Samples from an additional 3 softwood fiberboard assemblies have begun aging during the past year to provide information on the variability of softwood fiberboard behavior. Aging and testing of softwood fiberboard will continue and additional data will be collected to support development of an aging model specific to softwood fiberboard.

  9. Decreases in bone blood flow and bone material properties in aging Fischer-344 rats

    NASA Technical Reports Server (NTRS)

    Bloomfield, Susan A.; Hogan, Harry A.; Delp, Michael D.

    2002-01-01

    The purpose of this study was to quantify precisely aging-induced changes in skeletal perfusion and bone mechanical properties in a small rodent model. Blood flow was measured in conscious juvenile (2 months old), adult (6 months old), and aged (24 months old) male Fischer-344 rats using radiolabeled microspheres. There were no significant differences in bone perfusion rate or vascular resistance between juvenile and adult rats. However, blood flow was lower in aged versus adult rats in the forelimb bones, scapulas, and femurs. To test for functional effects of this decline in blood flow, bone mineral density and mechanical properties were measured in rats from these two age groups. Bone mineral density and cross-sectional moment of inertia in femoral and tibial shafts and the femoral neck were significantly larger in the aged versus adult rats, resulting in increased (+14%-53%) breaking strength and stiffness. However, intrinsic material properties at midshaft of the long bones were 12% to 25% lower in the aged rats. Although these data are consistent with a potential link between decreased perfusion and focal alterations in bone remodeling activity related to clinically relevant bone loss, additional studies are required to establish the mechanisms for this putative relationship.

  10. Modifications of the Response of Materials to Shock Loading by Age Hardening

    NASA Astrophysics Data System (ADS)

    Millett, Jeremy C. F.

    2015-10-01

    The shock response of two age-hardened alloys, aluminum 6061 and copper-2 wt pct beryllium (CuBe), has been investigated in terms of their microstructual state; either solution treated or age hardened. While age hardening induces large increases in strength at quasi-static strain rates, age hardening does not produce the same magnitude of strength increase during shock loading. Examination of the shocked microstructures (of 6061) indicates that the presence of a fine distribution of precipitates throughout the microstructure hinders the motion and generation of dislocations and hence reduces the strain-rate sensitivity of the aged material, thus allowing the properties of the solution-treated state to approach those of the aged. It has also been observed that the shear strength of solution-treated CuBe is near identical to that of pure copper. It is suggested that this is the result of two competing processes; large lattice strains as beryllium substitutes onto the copper lattice inducing a high degree of solution strengthening acting against a reduction in shear strength caused by twinning in the alloy.

  11. Evaluation of dredged material proposed for ocean disposal from MOTBY

    SciTech Connect

    Barrows, E.S.; Mayhew, H.L.; Word, J.Q.

    1996-09-01

    The National Park Service, US Department of the Interior requested U.S. Army Corps of Engineers/New York District (USACE-NYD) to evaluate sediments around the Military Ocean Terminal (MOTBY) in Bayonne, New Jersey for unconfined ocean disposal at the Mud Dump Site. Sediment samples were collected from MOTBY. Tests and analyses were conducted on MOTBY sediment core samples. The evaluation of proposed dredged material from MOTBY included grain size and total organic carbon (TOC) analyses and one acute toxicity test with the amphipod Ampelisca abdita. In addition to this benthic toxicity test, a bioaccumulation test (28-day exposure) was conducted.

  12. Evaluation of hardness and wear resistance of interim restorative materials

    PubMed Central

    Savabi, Omid; Nejatidanesh, Farahnaz; Fathi, Mohamad Hossein; Navabi, Amir Arsalan; Savabi, Ghazal

    2013-01-01

    Background: The interim restorative materials should have certain mechanical properties to withstand in oral cavity. The aim of this study was to evaluate the hardness and wear resistance of interim restorative materials. Materials and Methods: Fifteen identical rectangular shape specimens with dimensions of 2 mm × 10 mm × 30 mm were made from 7 interim materials (TempSpan, Protemp 3 Garant, Revotek, Unifast LC, Tempron, Duralay, and Acropars). The Vickers hardness and abrasive wear of specimens were tested in dry conditions and after 1 week storage in artificial saliva. The depth of wear was measured using surface roughness inspection device. Data were subjected to Kruskal–Wallis and Mann–Whitney tests. The Pearson correlation coefficient was used to determine the relationship between hardness and wear (α =0.05). Results: TempSpan had the highest hardness. The wear resistance of TempSpan (in dry condition) and Revotek (after conditioning in artificial saliva) was significantly higher (P < 0.05). There was no statistically significant correlation between degree of wear and hardness of the materials (P = 0.281, r = −0.31). Conclusion: Hardness and wear resistance of interim resins are material related rather than category specified. PMID:23946734

  13. Dielectric Spectroscopy Analysis of Aged EVOH films with Application to Deterioration of Food Packaging Materials

    NASA Astrophysics Data System (ADS)

    Hoeller, Timothy

    2007-06-01

    Samples of EVOH films from compositions of 29 - 44 mol% ethylene content were exposed to thermal aging with and without light exposure. The results of Dielectric Spectroscopy on select samples showed Cole-Cole plots of skewed dielectric constant indicating multiple distributions of dipole relaxation times. The onset for decreases in dielectric response occurs earlier in samples exposed to elevated temperature under light exposure. Lower permittivity is exhibited in samples of higher ethylene content. Results from heat exposed samples are presented. Colorimetric analysis indicates only a slight film yellowing in one case. Raman spectroscopy on untreated films discerns changes in the C-C-O stretch associated with the alcohol. The effects of aging on microstructure may cause hindrance of molecular motion from moisture desorption. Slight material degradation occurs from film hardening presumably due to crosslinking. An electrical circuit model of the conduction processes associated with the EVOH films is presented. Dielectric analysis shows promise for monitoring material changes related to deterioration. We are also using these methods to understand Fluorescence Imaging which has been recently released for paper and plastic materials analysis. Future work may include refinement of these techniques for identification of changes in material properties correlated to packaging material barrier resistance.

  14. Physical property comparison of 11 soft denture lining materials as a function of accelerated aging.

    PubMed

    Dootz, E R; Koran, A; Craig, R G

    1993-01-01

    Soft denture-lining materials are an important treatment option for patients who have chronic soreness associated with dental prostheses. Three distinctly different types of materials are generally used. These are plasticized polymers or copolymers, silicones, or polyphosphazene fluoroelastomer. The acceptance of these materials by patients and dentists is variable. The objective of this study is to compare the tensile strength, percent elongation, hardness, tear strength, and tear energy of eight plasticized polymers or copolymers, two silicones, and one polyphosphazene fluoroelastomer. Tests were run at 24 hours after specimen preparation and repeated after 900 hours of accelerated aging in a Weather-Ometer device. The data indicated a wide range of physical properties for soft denture-lining materials and showed that accelerated aging dramatically affected the physical and mechanical properties of many of the elastomers. No soft denture liner proved to be superior to all others. The data obtained should provide clinicians with useful information for selecting soft denture lining materials for patients. PMID:8455156

  15. New Technique for Evaluating Adhesion Properties between Soft Materials

    NASA Astrophysics Data System (ADS)

    Sato, Takaya; Goto, Motoaki; Nakano, Ken; Suzuki, Atsushi

    2005-11-01

    A new, simple apparatus for measuring the surface adhesion properties of soft materials was designed, where the adhesion force of a point contact between soft materials and the total energy required to separate the contact can be measured using the springs of phosphor-bronze thin plates with strain gauges. The adhesion between swollen hydrogels was studied here by this simple technique in air at room temperature. The gels used in the present preliminary experiments were poly(sodium acrylate) hydrogels physically cross-linked by aluminum ions. The adhesion force and the separation energy showed a power-law increase with separation velocity. The apparatus was applied to evaluate the adhesion properties of seven anti-inflammatory analgesic cataplasms on the market. It was found that the easiness to separate (rank of adhesion force and the separation energy) was consistent with the results of those obtained by organoleptic evaluations.

  16. A simple-rapid method to separate uranium, thorium, and protactinium for U-series age-dating of materials.

    PubMed

    Knight, Andrew W; Eitrheim, Eric S; Nelson, Andrew W; Nelson, Steven; Schultz, Michael K

    2014-08-01

    Uranium-series dating techniques require the isolation of radionuclides in high yields and in fractions free of impurities. Within this context, we describe a novel-rapid method for the separation and purification of U, Th, and Pa. The method takes advantage of differences in the chemistry of U, Th, and Pa, utilizing a commercially-available extraction chromatographic resin (TEVA) and standard reagents. The elution behavior of U, Th, and Pa were optimized using liquid scintillation counting techniques and fractional purity was evaluated by alpha-spectrometry. The overall method was further assessed by isotope dilution alpha-spectrometry for the preliminary age determination of an ancient carbonate sample obtained from the Lake Bonneville site in western Utah (United States). Preliminary evaluations of the method produced elemental purity of greater than 99.99% and radiochemical recoveries exceeding 90% for U and Th and 85% for Pa. Excellent purity and yields (76% for U, 96% for Th and 55% for Pa) were also obtained for the analysis of the carbonate samples and the preliminary Pa and Th ages of about 39,000 years before present are consistent with (14)C-derived age of the material. PMID:24681438

  17. Non-destructive evaluation of composite materials using ultrasound

    NASA Technical Reports Server (NTRS)

    Miller, J. G.

    1984-01-01

    Investigation of the nondestructive evaluation of advanced composite-laminates is summarized. Indices derived from the measurement of fundamental acoustic parameters are used in order to quantitatively estimate the local material properties of the laminate. The following sections describe ongoing studies of phase insensitive attenuation measurements, and discuss several phenomena which influences the previously reported technique of polar backscatter. A simple and effective programmable gate circuit designed for use in estimating attenuation from backscatter is described.

  18. Nondestructive evaluation of critical composite material structural elements

    NASA Astrophysics Data System (ADS)

    Duke, John C., Jr.; Lesko, John J.; Weyers, R.

    1996-11-01

    A small span bridge that has suffered corrosive deterioration of a number of the steel structural members is in the process of being rehabilitated with glass and carbon fiber reinforced, pultruded polymer structural beams. As part of a comprehensive research program to develop methods for modeling long term durability of the composite material, nondestructive evaluation if being used to provide a preliminary assessment of the initial condition of the beams as well as to monitor the deterioration of the beams during service.

  19. Evaluating candidate lost circulation materials for geothermal drilling

    SciTech Connect

    Loeppke, G.

    1986-01-01

    Sandia National Laboratories' Geothermal Technology Development Division is working to advance the state of the art of lost circulation prevention and control. For this purpose, a large-scale lost Circulation Test Facility was designed and built. This paper addresses the evaluation of candidate lost circulation materisl using this facility and also using the recommended practice of API RP 131. Test results from these facilities are compared and discussed for the materials tested.

  20. Age- and Race-Related Differences in Human Scleral Material Properties

    PubMed Central

    Grytz, Rafael; Fazio, Massimo A.; Libertiaux, Vincent; Bruno, Luigi; Gardiner, Stuart; Girkin, Christopher A.; Downs, J. Crawford

    2014-01-01

    Purpose. We tested the hypothesis that there are age- and race-related differences in posterior scleral material properties, using eyes from human donors of European (20–90 years old, n = 40 eyes) and African (23–74 years old, n = 22 eyes) descent. Methods. Inflation tests on posterior scleral shells were performed while full-field, three-dimensional displacements were recorded using laser speckle interferometry. Scleral material properties were fit to each eye using a microstructure-based constitutive formulation that incorporates the collagen fibril crimp and the local anisotropic collagen architecture. The effects of age and race were estimated using Generalized Estimating Equations, while accounting for intradonor correlations. Results. The shear modulus significantly increased (P = 0.038) and collagen fibril crimp angle significantly decreased with age (P = 0.002). Donors of African descent exhibited a significantly higher shear modulus (P = 0.019) and showed evidence of a smaller collagen fibril crimp angle (P = 0.057) compared to donors of European descent. The in-plane strains in the peripapillary sclera were significantly lower with age (P < 0.015) and African ancestry (P < 0.015). Conclusions. The age- and race-related differences in scleral material properties result in a loss of scleral compliance due to a higher shear stiffness and a lower level of stretch at which the collagen fibrils uncrimp. The loss of compliance should lead to larger high frequency IOP fluctuations and changes in the optic nerve head (ONH) biomechanical response in the elderly and in persons of African ancestry, and may contribute to the higher susceptibility to glaucoma in these at-risk populations. PMID:25389203

  1. A new tribological test for candidate brush seal materials evaluation

    SciTech Connect

    Fellenstein, J.A.; DellaCorte, C.

    1994-10-01

    A new tribological test for candidate brush seal materials evaluation has been developed. The sliding contact between the brush seal wires and their mating counterface journal is simulated by testing a small tuft of wire against the outside diameter of a high speed rotating shaft. The test configuration is similar to a standard block on ring geometry. The new tester provides the capability to measure both the friction and wear of candidate wire and counterface materials under controlled loading conditions in the gram to kilogram range. A wide test condition latitude of speeds (1 to 27 m/s), temperatures (25 to 700C), and loads (0.5 to 10 N) enables the simulation of many of the important tribological parameters found in turbine engine brush seals. This paper describes the new test rig and specimen configuration and presents initial data for candidate seal materials comparing tuft test results and wear surface morphology to field tested seal components.

  2. Development and evaluation of die and container materials

    NASA Technical Reports Server (NTRS)

    Wills, R. R.; Niesz, D. E.

    1979-01-01

    X = 0.75 Beta prime Sialon (a silicon aluminum oxynitride) and Sibeon (silicon beryllium oxynitride) are promising die materials. In sessile drop tests in contact with molten silicon, beryllium contamination was less than ppm and aluminum contamination 50 ppm. A shaping die of the Sialon material was successfully fabricated. Dry milling studies for the preparation of Si3N4-Al2O3-ALN mixtures were performed with butanol, acetic anhydride, oleic acid, and triethanolamine milling aids. Optimum mixing was achieved with 0.15 percent triethanolamine using a milling time of 8 hours. Preliminary evaluation of Sibeon materials indicates that they are more resistent to molten silicon attack than Sialon. Silicon contamination from the beryllium was less than aluminum contamination even though the aluminum impurity level in the Sibeon was only 450 to 1300 ppm. Work designed to produce an aluminum-free Sibeon is described.

  3. A New Tribological Test for Candidate Brush Seal Materials Evaluation

    NASA Technical Reports Server (NTRS)

    Fellenstein, James A.; Dellacorte, Christopher

    1994-01-01

    A new tribological test for candidate brush seal materials evaluation has been developed. The sliding contact between the brush seal wires and their mating counterface journal is simulated by testing a small tuft of wire against the outside diameter of a high speed rotating shaft. The test configuration is similar to a standard block on ring geometry. The new tester provides the capability to measure both the friction and wear of candidate wire and counterface materials under controlled loading conditions in the gram to kilogram range. A wide test condition latitude of speeds (1 to 27 m/s), temperatures (25 to 700 C), and loads (0.5 to 10 N) enables the simulation of many of the important tribological parameters found in turbine engine brush seals. This paper describes the new test rig and specimen configuration and presents initial data for candidate seal materials comparing tuft test results and wear surface morphology to field tested seal components.

  4. On the Use of Accelerated Aging Methods for Screening High Temperature Polymeric Composite Materials

    NASA Technical Reports Server (NTRS)

    Gates, Thomas S.; Grayson, Michael A.

    1999-01-01

    A rational approach to the problem of accelerated testing of high temperature polymeric composites is discussed. The methods provided are considered tools useful in the screening of new materials systems for long-term application to extreme environments that include elevated temperature, moisture, oxygen, and mechanical load. The need for reproducible mechanisms, indicator properties, and real-time data are outlined as well as the methodologies for specific aging mechanisms.

  5. Friction, mechanical and ageing properties of surface modified materials for space debris capture

    NASA Astrophysics Data System (ADS)

    Ferraris, S.; Perero, S.; Gautier di Confiengo, G.; Chiesa, A.; Messidoro, A.; Ferraris, M.

    2016-03-01

    Space debris removal is a challenging problem for a clean and safe space environment. The present paper focuses on a novel concept of capture mechanism in the framework of technologies, strategies and concepts known as "tentacles with belts" method. Within this framework two different strategies (based on inorganic or organic materials) have been developed in order to improve the capture efficiency of the belts. The mechanical, tribological and ageing characterization of modified belt fabrics for space application is reported and discussed.

  6. FIFTH STATUS REPORT: TESTING OF AGED SOFTWOOD FIBERBOARD MATERIAL FOR THE 9975 SHIPPING PACKAGE

    SciTech Connect

    Daugherty, W.; Skidmore, E.; Dunn, K.

    2014-04-15

    Samples have been prepared from a 9975 lower fiberboard subassembly fabricated from softwood fiberboard. Physical, mechanical and thermal properties have been measured following varying periods of conditioning in each of several environments. These tests have been conducted in the same manner as previous testing on cane fiberboard samples. Overall, similar aging trends are observed for softwood and cane fiberboard samples, with a few differences. Some softwood fiberboard properties tend to degrade faster in elevated humidity environments, while some cane fiberboard properties degrade faster in the hotter dry environments. As a result, it is premature to assume both materials will age at the same rates, and the preliminary aging models developed for cane fiberboard might not apply to softwood fiberboard. However, it is expected that both cane and softwood fiberboard assemblies will perform satisfactorily in conforming packages stored in a typical KAC storage environment for up to 15 years. Aging and testing of softwood fiberboard will continue and additional data will be collected. Additional samples will be added to each aging environment, to support development of an aging model specific to softwood fiberboard. Post-conditioning data have been measured on samples from a single softwood fiberboard assembly, and baseline data are also available from a limited number of vendor-provided samples. This provides minimal information on the possible sample-to-sample variation exhibited by softwood fiberboard. Data to date are generally consistent with the range seen in cane fiberboard, but some portions of the data trends are skewed toward the lower end of that range. Two additional softwood fiberboard source packages have been obtained and will begin to provide data on the range of variability of this material.

  7. FOURTH STATUS REPORT: TESTING OF AGED SOFTWOOD FIBERBOARD MATERIAL FOR THE 9975 SHIPPING PACKAGE

    SciTech Connect

    Daugherty, W.

    2013-03-05

    Samples have been prepared from a 9975 lower fiberboard subassembly fabricated from softwood fiberboard. Physical, mechanical and thermal properties have been measured following varying periods of conditioning in each of several environments. These tests have been conducted in the same manner as previous testing on cane fiberboard samples. Overall, similar aging trends are observed for softwood and cane fiberboard samples, with a few differences. Some softwood fiberboard properties tend to degrade faster in elevated humidity environments, while some cane fiberboard properties degrade faster in the hotter dry environments. As a result, it is premature to assume both materials will age at the same rates, and the preliminary aging models developed for cane fiberboard might not apply to softwood fiberboard. However, it is expected that both cane and softwood fiberboard assemblies will perform satisfactorily in conforming packages stored in a typical KAMS environment for up to 15 years. Aging and testing of softwood fiberboard will continue and additional data will be collected. Post-conditioning data have been measured on samples from a single softwood fiberboard assembly, and baseline data are also available from a limited number of vendor-provided samples. This provides minimal information on the possible sample-to-sample variation exhibited by softwood fiberboard. Data to date are generally consistent with the range seen in cane fiberboard, but some portions of the data trends are skewed toward the lower end of that range. Further understanding of the variability of softwood fiberboard properties will require testing of additional material.

  8. Subretinal Hyper-Reflective Material in the Comparison of Age-related Macular Degeneration Treatments Trials

    PubMed Central

    Willoughby, Alex S.; Ying, Gui-shuang; Toth, Cynthia A.; Maguire, Maureen G.; Burns, Russell E.; Grunwald, Juan E.; Daniel, Ebenezer; Jaffe, Glenn J.

    2015-01-01

    Objective To evaluate the association of subretinal hyper-reflective material (SHRM) with visual acuity (VA), geographic atrophy (GA) and scar in the Comparison of Age related Macular Degeneration Treatments Trials (CATT) Design Prospective cohort study within a randomized clinical trial. Participants The 1185 participants in CATT. Methods Participants were randomly assigned to ranibizumab or bevacizumab treatment monthly or as-needed. Masked readers graded scar and GA on fundus photography and fluorescein angiography images, SHRM on time domain (TD) and spectral domain (SD) optical coherence tomography (OCT) throughout 104 weeks. Measurements of SHRM height and width in the fovea, within the center 1mm2, or outside the center 1mm2 were obtained on SD-OCT images at 56 (n=76) and 104 (n=66) weeks. VA was measured by certified examiners. Main Outcome Measures SHRM presence, location and size, and associations with VA, scar, and GA. Results Among all CATT participants, the percentage with SHRM at enrollment was 77%, decreasing to 68% at 4 weeks after treatment and 54% at 104 weeks. At 104 weeks, scar was present more often in eyes with persistent SHRM than eyes with SHRM that resolved (64% vs. 31%; p<0.0001). Among eyes with detailed evaluation of SHRM at weeks 56 (n=76) and 104 (n=66), mean [SE] VA letter score was 73.5 [2.8], 73.1 [3.4], 65.3 [3.5], and 63.9 [3.7] when SHRM was absent, present outside the central 1mm2, present within the central 1mm2 but not the foveal center, or present at the foveal center (p=0.02). SHRM was present at the foveal center in 43 (30%), within the central 1mm2 in 21 (15%) and outside the central 1mm2 in 19 (13%). When SHRM was present, the median maximum height in microns under the fovea, within the central 1 mm2 including the fovea and anywhere within the scan was 86; 120; and 122, respectively. VA was decreased with greater SHRM height and width (p<0.05). Conclusions SHRM is common in eyes with NVAMD and often persists after anti

  9. Research Approach for Aging and Evaluating Diesel Exhaust catalysts

    SciTech Connect

    Wayne, Scott

    2000-08-20

    To determine the impact of diesel fuel sulfur levels on emissions control devices that could lower emissions of oxides of nitrogen (NOX) and particulate matter (PM) from on-highway trucks and buses in the 2002-2004 model years. West Virginia University is evaluating: - Diesel Oxidation Catalysts - Lean NOX Catalysts

  10. Aging gauge

    DOEpatents

    Betts, Robert E.; Crawford, John F.

    1989-04-04

    An aging gauge comprising a container having a fixed or a variable sized t opening with a cap which can be opened to control the sublimation rate of a thermally sublimational material contained within the container. In use, the aging gauge is stored with an item to determine total heat the item is subjected to and also the maximum temperature to which the item has been exposed. The aging gauge container contains a thermally sublimational material such as naphthalene or similar material which has a low sublimation rate over the temperature range from about 70.degree. F. to about 160.degree. F. The aging products determined by analyses of a like item aged along with the aging gauge for which the sublimation amount is determined is employed to establish a calibration curve for future aging evaluation. The aging gauge is provided with a means for determining the maximum temperature exposure (i.e., a thermally indicating material which gives an irreversible color change, Thermocolor pigment). Because of the relationship of doubling reaction rates for increases of 10.degree. C., equivalency of item used in accelerated aging evaluation can be obtained by referring to a calibration curve depicting storage temperature on the abscissa scale and multiplier on the ordinate scale.

  11. Aging gauge

    DOEpatents

    Betts, Robert E.; Crawford, John F.

    1989-01-01

    An aging gauge comprising a container having a fixed or a variable sized t opening with a cap which can be opened to control the sublimation rate of a thermally sublimational material contained within the container. In use, the aging gauge is stored with an item to determine total heat the item is subjected to and also the maximum temperature to which the item has been exposed. The aging gauge container contains a thermally sublimational material such as naphthalene or similar material which has a low sublimation rate over the temperature range from about 70.degree. F. to about 160.degree. F. The aging products determined by analyses of a like item aged along with the aging gauge for which the sublimation amount is determined is employed to establish a calibration curve for future aging evaluation. The aging gauge is provided with a means for determining the maximum temperature exposure (i.e., a thermally indicating material which gives an irreversible color change, Thermocolor pigment). Because of the relationship of doubling reaction rates for increases of 10.degree. C., equivalency of item used in accelerated aging evaluation can be obtained by referring to a calibration curve depicting storage temperature on the abscissa scale and multiplier on the ordinate scale.

  12. 40Ar/39Ar age of material returned from asteroid 25143 Itokawa

    NASA Astrophysics Data System (ADS)

    Park, Jisun; Turrin, Brent D.; Herzog, Gregory F.; Lindsay, Fara N.; Delaney, Jeremy S.; Swisher, Carl C.; Uesugi, Masayuki; Karouji, Yuzuru; Yada, Toru; Abe, Masanao; Okada, Tatsuaki; Ishibashi, Yukihiro

    2015-11-01

    The Hayabusa mission to asteroid 25143, Itokawa, brought back 2000 small particles, which most closely resemble material found in LL4-6 chondrites. We report an 40Ar/39Ar age of 1.3 ± 0.3 Ga for a sample of Itokawa consisting of three grains with a total mass of ~2 μg. This age is lower than the >4.0 Ga ages measured for 75% of LL chondrites but close to one for Y-790964 and its pairs. The flat 40Ar/39Ar release spectrum of the sample suggests complete degassing 1.3 Ga ago. Recent solar heating in Itokawa's current orbit does not appear likely to have reset that age. Solar or impact heating 1.3 Ga ago could have done so. If impact heating was responsible, then the 1.3 Ga age sets an upper bound on the time at which the Itokawa rubble pile was assembled and suggests that rubble pile creation was an ongoing process in the inner solar system for at least the first 3 billion years of solar system history.

  13. Evaluating the Reliability of Three Different Dental Age Estimation Methods in Visakhapatnam Children

    PubMed Central

    Vabbalareddy, Raja Sekhar; V Vanga, Narasimha Rao

    2014-01-01

    ABSTRACT% Dental age is important for treatment planning in the specialities of pedodontics and orthodontics. Although, Demirjian's method was considered standard for dental age estimation, it may not be reliable for all population. Aim: The goal of the study was to evaluate the reliability of Demir-jian's, Haavikko's and Willems method of dental age estimation methods in Visakhapatnam (Andhra Pradesh, India) children. Study design: One hundred and two children of 6 to 14 years old who underwent panaromic digital radiography for routine diagnostic purposes were included. Dental age was calculated using Demirjian's, Haavikko's and Willems methods and compared with chronologic age for each patient. Results: Dental age showed a significant overestimation by Demirjian's method with a mean difference of 0.55 year and underestimation by Haavikko's and Willems methods with a mean difference of 1.95 and 0.20 year respectively when compared with chronologic age. The mean difference between dental age and chronologic age was not significant in Willems method which shows a close relation between dental and chronologic ages. Conclusion: The dental age estimation by Willems method is found to be more accurate than Demirjian's and Haavikko's methods in Visakhapatnam children. How to cite this article: Patnana AK, Vabbalareddy RS, Vanga NRV. Evaluating the Reliability of Three Different Dental Age Estimation Methods in Visakhapatnam Children. Int J Clin Pediatr Dent 2014;7(3):186-191. PMID:25709299

  14. Gender bias in the evaluation of new age music.

    PubMed

    Colley, Ann; North, Adrian; Hargreaves, David J

    2003-04-01

    Eminent composers in Western European art music continue to be predominantly male and eminence in contemporary pop music is similarly male dominated. One contributing factor may be the continuing under-valuation of women's music. Possible anti-female bias in a contemporary genre was investigated using the Goldberg paradigm to elicit judgments of New Age compositions. Since stronger stereotyping effects occur when information provided about individuals is sparse, fictitious male and female composers were presented either by name only or by name with a brief biography. Evidence for anti-female bias was found in the name-only condition and was stronger when liking for the music was controlled. Other findings were the tendency for females to give higher ratings, and the association of gender differences in liking of the music with ratings of quality in the name-only condition. These results are relevant to the design of formal assessment procedures for musical composition. PMID:12778980

  15. Emotional expressions preferentially elicit implicit evaluations of faces also varying in race or age.

    PubMed

    Craig, Belinda M; Lipp, Ottmar V; Mallan, Kimberley M

    2014-10-01

    Both facial cues of group membership (race, age, and sex) and emotional expressions can elicit implicit evaluations to guide subsequent social behavior. There is, however, little research addressing whether group membership cues or emotional expressions are more influential in the formation of implicit evaluations of faces when both cues are simultaneously present. The current study aimed to determine this. Emotional expressions but not race or age cues elicited implicit evaluations in a series of affective priming tasks with emotional Caucasian and African faces (Experiments 1 and 2) and young and old faces (Experiment 3). Spontaneous evaluations of group membership cues of race and age only occurred when those cues were task relevant, suggesting the preferential influence of emotional expressions in the formation of implicit evaluations of others when cues of race or age are not salient. Implications for implicit prejudice, face perception, and person construal are discussed. PMID:25046242

  16. STATUS REPORT FOR AGING STUDIES OF EPDM O-RING MATERIAL FOR THE H1616 SHIPPING PACKAGE

    SciTech Connect

    Stefek, T.; Daugherty, W.; Skidmore, E.

    2012-08-31

    This is an interim status report for tasks carried out per Task Technical Plan SRNL-STI-2011-00506. A series of tasks/experiments are being performed at the Savannah River National Laboratory to monitor the aging performance of ethylene propylene diene monomer (EPDM) Orings used in the H1616 shipping package. The data will support the technical basis to extend the annual maintenance of the EPDM O-rings in the H1616 shipping package and to predict the life of the seals at bounding service conditions. Current expectations are that the O-rings will maintain a seal at bounding normal temperatures in service (152 F) for at least 12 months. The baseline aging data review suggests that the EPDM O-rings are likely to retain significant mechanical properties and sealing force at bounding service temperatures to provide a service life of at least 2 years. At lower, more realistic temperatures, longer service life is likely. Parallel compression stress relaxation and vessel leak test efforts are in progress to further validate this assessment and quantify a more realistic service life prediction. The H1616 shipping package O-rings were evaluated for baseline property data as part of this test program. This was done to provide a basis for comparison of changes in material properties and performance parameters as a function of aging. This initial characterization was limited to physical and mechanical properties, namely hardness, thickness and tensile strength. These properties appear to be consistent with O-ring specifications. Three H1616-1 Containment Vessels were placed in test conditions and are aging at temperatures ranging from 160 to 300 F. The vessels were Helium leak-tested initially and have been tested at periodic intervals after cooling to room temperature to determine if they meet the criterion of leaktightness defined in ANSI standard N14.5-97 (< 1E-07 std cc air/sec at room temperature). To date, no leak test failures have occurred. The cumulative time at

  17. Availability of Nitrogen in Poultry litter: Influence of Bedding Material and Litter Age

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field experiments were conducted to evaluate the influence of bedding material on the availability of N in poultry to crop production. Experiments included two corn grain trials in which litter sources were applied at a rate of 125 lbs N acre-1 and inorganic fertilizer was applied at 0, 50, 100, 1...

  18. Effect of material aging on parachute pack life: a synopsis of Sandia National Laboratories studies

    SciTech Connect

    Auerbach, I.; Mead, J.W.; Mead, K.E.; Ericksen, R.H.; Burns, F.B.; Renschler, C.L.

    1984-01-01

    A systematic study of the effects of environmental factors on nylon 66 and Kevlar 29 strength degradation in parachute components is being conducted at Sandia National Laboratories. It includes: (1) accelerated aging studies in air, inert environments, humidity, ozone, and smog; (2) a 25-year surveillance program of parachutes in a variety of natural climatic environments; (3) moisture absorption as a function of humidity; (4) effects of surface coatings normally applied to parachutes; and (5) development of nondestructive evaluation techniques which can be used to map mechanical properties over the entire parachute surface. The accelerated aging and moisture absorption studies show that air, humidity, and smog contribute to degradation. Chemiluminescence, gas chromatographic pyrograms, and uv spectroscopy show promise as nondestructive evaluation techniques.

  19. Ultrasound velocity test to decay evaluation on decorative stone after different artificial ageing treatments

    NASA Astrophysics Data System (ADS)

    Fioretti, Giovanna; Andriani, Gioacchino Francesco

    2016-04-01

    Ultrasound propagation velocity depends on several physical properties, for instance density, porosity and textural discontinuities within stones. These properties are strongly influenced by state of conservation of materials and their modification can be considered decay markers; therefore, ultrasound velocity measurement represents a non-destructive technique to evaluate the decay underway on employed stone. In this study, samples of the Avorio variety, an Apulian limestones, were processed to artificial ageing treatments, in particular thermal shocks, extreme thermal exposure at high temperatures between 200 and 600°C, and cycles of immersion of rock samples into saline solution alternating with drying phases in muffle furnace. Effects of induced deterioration were examined by comparing p-wave ultrasound velocity values, visual appearance and mass loss with water absorption values and capillarity test results. This research suggests first that the ultrasound velocity test can be considered a valuable non-invasive technique to assess the state of decay of decorative and building stones. Furthermore, in order to simulate dangerous and extreme environmental conditions and study their influence on the stone decay patterns, new considerations and suggestions about ageing test and procedures were proposed.

  20. Age-Related Changes to the Neural Correlates of Social Evaluation

    PubMed Central

    Cassidy, Brittany S.; Shih, Joanne Y.; Gutchess, Angela H.

    2012-01-01

    Recent work suggests the existence of a specialized neural system underlying social processing that may be relatively spared with age, unlike pervasive aging-related decline occurring in many cognitive domains. We investigated how neural mechanisms underlying social evaluation are engaged with age, and how age-related changes to socioemotional goals affect recruitment of regions within this network. In a functional MRI study, fifteen young and fifteen older adults formed behavior-based impressions of individuals. They also responded to a prompt that was interpersonally meaningful, social but interpersonally irrelevant, or non-social. Both age groups engaged regions implicated in mentalizing and impression formation when making social relative to non-social evaluations, including dorsal and ventral medial prefrontal cortices, precuneus, and temporoparietal junction. Older adults had increased activation over young in right temporal pole when making social relative to non-social evaluations, suggesting reliance on past experiences when evaluating others. Young had greater activation than old in posterior cingulate gyrus when making interpersonally irrelevant, compared to interpersonally meaningful, evaluations, potentially reflecting enhanced valuation of this information. The findings demonstrate the age-related preservation of the neural correlates underlying social evaluation, and suggest that functioning in these regions might be mediated by age-related changes in socioemotional goals. PMID:22439896

  1. Evaluation of new stratospheric age tracers and SF6

    NASA Astrophysics Data System (ADS)

    Laube, J. C.; Gallacher, E.; Oram, D.; Boenisch, H.; Engel, A.; Fraser, P. J.; Röckmann, T.; Sturges, W. T.

    2015-12-01

    Sulphur hexafluoride (SF6) is a very long-lived, potent greenhouse gas. Its abundances continue to increase in the atmosphere. Due to its inert behaviour it has also been extensively used as a tracer of transport in the ocean, the troposphere and the stratosphere. We here combine long-term tropospheric records obtained from the Cape Grim Baseline station, Tasmania, with stratospheric data from high-altitude aircraft and balloon campaigns. We then assess the novel use of several alternative transport tracers (e.g. C2F6, C3F8 and HFC-23) in the stratosphere. The results indicate good suitability for some of these gases in terms of their inertness, tropospheric growth rates and measurement precisions. In addition we and compare the derived mean ages to those obtained from SF6 and find indications for the possibility of the existence of a stratospheric SF6 sink. The latter finding would also imply that the total atmospheric lifetime of SF6 is substantially shorter than previously believed, with further implications for its use as a transport tracer in the stratosphere.

  2. Criteria for clinical translucency evaluation of direct esthetic restorative materials.

    PubMed

    Lee, Yong-Keun

    2016-08-01

    The purpose of this review was to suggest practical criteria for the clinical translucency evaluation of direct esthetic restorative materials, and to review the translucency with these criteria. For the evaluation of reported translucency values, measuring instrument and method, specimen thickness, background color, and illumination should be scrutinized. Translucency parameter (TP) of 15 to 19 could be regarded as the translucency of 1 mm thick human enamel. Visual perceptibility threshold for translucency difference in contrast ratio (ΔCR) of 0.07 could be transformed into ΔTP value of 2. Translucency differences between direct and indirect resin composites were perceivable (ΔTP > 2). Universal and corresponding flowable resin composites did not show perceivable translucency differences in most products. Translucency differed significantly by the product within each shade group, and by the shade group within each product. Translucency of human enamel and perceptibility threshold for translucency difference may be used as criteria for the clinical evaluation of translucency of esthetic restorative materials. PMID:27508156

  3. Criteria for clinical translucency evaluation of direct esthetic restorative materials

    PubMed Central

    2016-01-01

    The purpose of this review was to suggest practical criteria for the clinical translucency evaluation of direct esthetic restorative materials, and to review the translucency with these criteria. For the evaluation of reported translucency values, measuring instrument and method, specimen thickness, background color, and illumination should be scrutinized. Translucency parameter (TP) of 15 to 19 could be regarded as the translucency of 1 mm thick human enamel. Visual perceptibility threshold for translucency difference in contrast ratio (ΔCR) of 0.07 could be transformed into ΔTP value of 2. Translucency differences between direct and indirect resin composites were perceivable (ΔTP > 2). Universal and corresponding flowable resin composites did not show perceivable translucency differences in most products. Translucency differed significantly by the product within each shade group, and by the shade group within each product. Translucency of human enamel and perceptibility threshold for translucency difference may be used as criteria for the clinical evaluation of translucency of esthetic restorative materials. PMID:27508156

  4. An evaluation of agreement between pectoral spines and otoliths for estimating ages of catfishes

    USGS Publications Warehouse

    Olive, J.A.; Schramm, Harold, Jr.; Gerard, Patrick D.; Irwin, E.

    2011-01-01

    Otoliths have been shown to provide more accurate ages than pectoral spine sections for several catfish populations; but sampling otoliths requires euthanizing the specimen, whereas spines can be sampled non-lethally. To evaluate whether, and under what conditions, spines provide the same or similar age estimates as otoliths, we examined data sets of individual fish aged from pectoral spines and otoliths for six blue catfish Ictalurus furcatus populations (n=420), 14 channel catfish Ictalurus punctatus populations (n=997), and 10 flathead catfish Pylodictus olivaris populations (n=947) from lotic and lentic waters throughout the central and eastern U.S. Logistic regression determined that agreement between ages estimated from otoliths and spines was consistently related to age, but inconsistently related to growth rate. When modeled at mean growth rate, we found at least 80% probability of no difference in spine- and otolith-assigned ages up to ages 4 and 5 for blue and channel catfish, respectively. For flathead catfish, an 80% probability of agreement between spine- and otolith-assigned ages did not occur at any age due to high incidence of differences in assigned ages even for age-1 fish. Logistic regression models predicted at least 80% probability that spine and otolith ages differed by ≤1 year up to ages 13, 16, and 9 for blue, channel, and flathead catfish, respectively. Age-bias assessment found mean spine-assigned age differed by less than 1 year from otolith-assigned age up to ages 19, 9, and 17 for blue catfish, channel catfish, and flathead catfish, respectively. These results can be used to help guide decisions about which structure is most appropriate for estimating catfish ages for particular populations and management objectives.

  5. Systematic evaluation of neutron shielding effects for materials

    SciTech Connect

    Ueki, K.; Ohashi, A.; Nariyama, N.; Nagayama, S.; Fujita, T.; Hattori, K.; Anayama, Y.

    1996-11-01

    Three types of experiments with a {sup 252}Cf neutron source are proposed to evaluate systematically the neutron shielding effects of a material. The type 1 experiment deals with each shielding material alone, the type 2 experiment combines a shielding material and a structural material, and the type 3 experiment constructs the optimization with the materials used in the type 2 experiment. In the stainless steel (SS) + polyethylene shielding system, because of the location of the SS slabs at the source side, the tenth layer of the polyethylene becomes approximately one-half the value as when the polyethylene is employed alone. This is the enhancement effect of the SS. In the type 3 experiment, the total thickness of the SS + polyethylene shielding system is 40 cm, and the total thicknesses of the SS and the polyethylene slabs are fixed at 25 and 15 cm thick, respectively. The minimum total dose-equivalent rate (neutron + secondary gamma rays) is observed when the polyethylene slabs are located at a 20-cm depth from the source side, with an arrangement of 20-cm-thick SS + 15-cm-thick polyethylene + 5-cm-thick and SS, and with a ratio of the maximum to the minimum dose-equivalent rate of 2.5. The shielding optimization can be constructed by combining the materials having different shielding characteristics. The experimental results of the three types of experiments are reproduced fairly well by using the continuous-energy Monte Carlo code MCNP 4A with a next-event surface crossing estimator.

  6. The Development and Evaluation of Physical Science Curriculum Materials Designed to Improve the Attitudes of the Secondary School Slow Learner.

    ERIC Educational Resources Information Center

    Milson, James Lee

    The purpose of this study was to develop and evaluate physical science curriculum materials suitable for secondary school age slow learners. A unit on measuring heat and temperature was developed, using guidelines based on a study of the characteristics of students of below-average intelligence (I.Q. between 75 to 90) and reading ability at or…

  7. Aging of nuclear station diesel generators: Evaluation of operating and expert experience: Phase 1, Study

    SciTech Connect

    Hoopingarner, K.R.; Vause, J.W.; Dingee, D.A.; Nesbitt, J.F.

    1987-08-01

    Pacific Northwest Laboratory evaluated operational and expert experience pertaining to the aging degradation of diesel generators in nuclear service. The research, sponsored by the US Nuclear Regulatory Commission (NRC), identified and characterized the contribution of aging to emergency diesel generator failures. This report, Volume I, reviews diesel-generator experience to identify the systems and components most subject to aging degradation and isolates the major causes of failure that may affect future operational readiness. Evaluations show that as plants age, the percent of aging-related failures increases and failure modes change. A compilation is presented of recommended corrective actions for the failures identified. This study also includes a review of current, relevant industry programs, research, and standards. Volume II reports the results of an industry-wide workshop held on May 28 and 29, 1986 to discuss the technical issues associated with aging of nuclear service emergency diesel generators.

  8. Aging

    PubMed Central

    Park, Dong Choon

    2013-01-01

    Aging is initiated based on genetic and environmental factors that operate from the time of birth of organisms. Aging induces physiological phenomena such as reduction of cell counts, deterioration of tissue proteins, tissue atrophy, a decrease of the metabolic rate, reduction of body fluids, and calcium metabolism abnormalities, with final progression onto pathological aging. Despite the efforts from many researchers, the progression and the mechanisms of aging are not clearly understood yet. Therefore, the authors would like to introduce several theories which have gained attentions among the published theories up to date; genetic program theory, wear-and-tear theory, telomere theory, endocrine theory, DNA damage hypothesis, error catastrophe theory, the rate of living theory, mitochondrial theory, and free radical theory. Although there have been many studies that have tried to prevent aging and prolong life, here we introduce a couple of theories which have been proven more or less; food, exercise, and diet restriction. PMID:24653904

  9. Aging.

    PubMed

    Park, Dong Choon; Yeo, Seung Geun

    2013-09-01

    Aging is initiated based on genetic and environmental factors that operate from the time of birth of organisms. Aging induces physiological phenomena such as reduction of cell counts, deterioration of tissue proteins, tissue atrophy, a decrease of the metabolic rate, reduction of body fluids, and calcium metabolism abnormalities, with final progression onto pathological aging. Despite the efforts from many researchers, the progression and the mechanisms of aging are not clearly understood yet. Therefore, the authors would like to introduce several theories which have gained attentions among the published theories up to date; genetic program theory, wear-and-tear theory, telomere theory, endocrine theory, DNA damage hypothesis, error catastrophe theory, the rate of living theory, mitochondrial theory, and free radical theory. Although there have been many studies that have tried to prevent aging and prolong life, here we introduce a couple of theories which have been proven more or less; food, exercise, and diet restriction. PMID:24653904

  10. Age related differences in mechanical demands imposed on the lower back by manual material handling tasks.

    PubMed

    Shojaei, Iman; Vazirian, Milad; Croft, Emily; Nussbaum, Maury A; Bazrgari, Babak

    2016-04-11

    The prevalence of low back pain (LBP) increases with age, yet the underlying mechanism(s) responsible for this remains unclear. To explore the role of biomechanical factors, we investigated age-related differences in lower-back biomechanics during sagittally-symmetric simulated manual material handling tasks. For each task, trunk kinematics and mechanical demand on the lower back were examined, from among 60 participants within five equal-sized and gender-balanced age groups spanning from 20 to 70 years old. The tasks involved lowering a 4.5kg load from an upright standing posture to both knee height and a fixed height and then lifting the load back to the initial upright posture. During these tasks, segmental body kinematics and ground reaction forces were collected using wireless inertial measurement units and a force platform. Overall, older participants completed the tasks with larger pelvic rotation and smaller lumbar flexion. Such adopted trunk kinematics resulted in larger peak shearing demand at the lower back in older vs. younger participants. These results suggest that older individuals may be at a higher risk for developing lower back pain when completing similar manual material handling tasks, consistent with epidemiological evidence for higher risks of occupational low back pain among this cohort. PMID:26556714