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Sample records for qualified kevlar composite

  1. Testing of Full Scale Flight Qualified Kevlar Composite Overwrapped Pressure Vessels

    NASA Technical Reports Server (NTRS)

    Greene, Nathanael; Saulsberry, Regor; Yoder, Tommy; Forsyth, Brad; Thesken, John; Phoenix, Leigh

    2007-01-01

    Many decades ago NASA identified a need for low-mass pressure vessels for carrying various fluids aboard rockets, spacecraft, and satellites. A pressure vessel design known as the composite overwrapped pressure vessel (COPV) was identified to provide a weight savings over traditional single-material pressure vessels typically made of metal and this technology has been in use for space flight applications since the 1970's. A typical vessel design consisted of a thin liner material, typically a metal, overwrapped with a continuous fiber yarn impregnated with epoxy. Most designs were such that the overwrapped fiber would carry a majority of load at normal operating pressures. The weight advantage for a COPV versus a traditional singlematerial pressure vessel contributed to widespread use of COPVs by NASA, the military, and industry. This technology is currently used for personal breathing supply storage, fuel storage for auto and mass transport vehicles and for various space flight and aircraft applications. The NASA Engineering and Safety Center (NESC) was recently asked to review the operation of Kevlar 2 and carbon COPVs to ensure they are safely operated on NASA space flight vehicles. A request was made to evaluate the life remaining on the Kevlar COPVs used on the Space Shuttle for helium and nitrogen storage. This paper provides a review of Kevlar COPV testing relevant to the NESC assessment. Also discussed are some key findings, observations, and recommendations that may be applicable to the COPV user community. Questions raised during the investigations have revealed the need for testing to better understand the stress rupture life and age life of COPVs. The focus of this paper is to describe burst testing of Kevlar COPVs that has been completed as a part of an the effort to evaluate the effects of ageing and shelf life on full scale COPVs. The test articles evaluated in this discussion had a diameter of 22 inches for S/N 014 and 40 inches for S/N 011. The

  2. Condition Assessment of Kevlar Composite Materials Using Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Washer, Glenn; Brooks, Thomas; Saulsberry, Regor

    2007-01-01

    This viewgraph presentation includes the following main concepts. Goal: To evaluate Raman spectroscopy as a potential NDE tool for the detection of stress rupture in Kevlar. Objective: Test a series of strand samples that have been aged under various conditions and evaluate differences and trends in the Raman response. Hypothesis: Reduction in strength associated with stress rupture may manifest from changes in the polymer at a molecular level. If so, than these changes may effect the vibrational characteristics of the material, and consequently the Raman spectra produced from the material. Problem Statement: Kevlar composite over-wrapped pressure vessels (COPVs) on the space shuttles are greater than 25 years old. Stress rupture phenomena is not well understood for COPVs. Other COPVs are planned for hydrogen-fueled vehicles using Carbon composite material. Raman spectroscopy is being explored as an non-destructive evaluation (NDE) technique to predict the onset of stress rupture in Kevlar composite materials. Test aged Kevlar strands to discover trends in the Raman response. Strength reduction in Kevlar polymer will manifest itself on the Raman spectra. Conclusions: Raman spectroscopy has shown relative changes in the intensity and FWHM of the 1613 cm(exp -1) peak. Reduction in relative intensity for creep, fleet leader, and SIM specimens compared to the virgin strands. Increase in FWHM has been observed for the creep and fleet leader specimens compared to the virgin strands. Changes in the Raman spectra may result from redistributing loads within the material due to the disruption of hydrogen bonding between crystallites or defects in the crystallites from aging the Kevlar strands. Peak shifting has not been observed to date. Analysis is ongoing. Stress measurements may provide a tool in the short term.

  3. Prediction of long-term failure in Kevlar 49 composites

    SciTech Connect

    Gerstle, F.P. Jr.

    1982-01-01

    Creep rupture data in Kevlar 49 epoxy usually exhibit considerable scatter: the coefficient of variation (CV) about the mean failure time at a given stress exceeds 100%. Quasi-static strength data, in contrast, shows little scatter: <4% CV for pressure vessels and <10% for impregnated strands. In this paper analysis of existing creep rupture data on Kevlar epoxy vessels at four storage pressures has produced an interesting and useful result. It was found that a significant portion of the scatter in failure times for pressure vessels is due to spool-to-spool variation in the eight spools of Kevlar fibers used to wind the vessels. The order rank of mean times to failure was consistent over a pressure range from 3400 to 4300 psi, 68 to 86% of short term burst. Also, the coefficient of variation about the mean failure time for each spool was less than that for the total sample. The statistical inference that the sample is nonhomogeneous was supported by a nonparametric check using the Kruskal-Wallis test, and by a parametric analysis of variance. The order rank found in long-term tests did not unequivocally agree with static strength ranks; several spool sets were distinctly high or low. The implication is that, while static strengths are not valid predictors of long-term behavior, short term creep rupture tests at high stress definitely are. The material difference which causes the spool-to-spool variations has not yet been identified for all eight spools. However, it appears that Kevlar behavior at lower pressures may be predicted through the use of curves fitted to the data for each spool. A power law relating failure time to pressure, t = t/sub 0/(p/p/sub 0/)/sup m/, was found to fit the data reasonably well. The implication is that, both in composite vessel design and in creep rupture experiments, the pressure (or stress) level be carefully controlled.

  4. Thermoviscoelastic characterization and predictions of Kevlar/epoxy composite laminates

    SciTech Connect

    Gramoll, K.C.

    1988-01-01

    This study consisted of two main parts, the thermoviscoelastic characterization of Kevlar 49/Fiberite 7714A epoxy composite lamina and the development of a numerical procedure to predict the viscoelastic response of any general laminate constructed from the same material. The four orthotropic material properties, S{sub 11}, S{sub 12}, S{sub 22}, and S{sub 66}, were characterized by 20-minute static creep tests on unidirectional ((0){sub s}, (10){sub s}, and (90){sub 16}) lamina specimens. A new numerical procedure to predict long-term laminate properties from lamina properties (obtained experimentally) was developed. Numerical instabilities and time constraints associated with viscoelastic numerical techniques were discussed and solved. The numerical procedure was incorporated into a user-friendly microcomputer program called Viscoelastic Composite Analysis Program (VCAP), which is available for IBM PC type computers. The program was designed for ease of use and includes graphics, menus, help messages, etc. The final phase of the study involved testing actual laminates constructed from the characterized material, Kevlar/epoxy, at various temperature and load levels for 4 to 5 weeks.

  5. Flight service evaluation of Kevlar-49 epoxy composite panels in wide-bodied commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    Stone, R. H.

    1982-01-01

    Kevlar-49 fairing panels, installed as flight service components on three l-1011's, were inspected after 8 years service. The fairings had accumulated a total of 62,000 hours, with one ship set having 20,850 hours service. Kevlar-49 components were found to be performing satisfactorily in service with no major problems. The only defects noted were minor impact damage, a few minor disbonds and a minor degree of fastener hole fraying and elongation. The service history to date indicates that Kevlar-49 epoxy composite materials have satisfactory service characteristics for use in aircraft secondary structures.

  6. Aging results for PRD 49 III/epoxy and Kevlar 49/epoxy composite pressure vessels

    NASA Technical Reports Server (NTRS)

    Hamstad, M. A.

    1983-01-01

    Kevlar 49/epoxy composite is growing in use as a structural material because of its high strength-to-weight ratio. Currently, it is used for the Trident rocket motor case and for various pressure vessels on the Space Shuttle. In 1979, the initial results for aging of filament-wound cylindrical pressure vessels which were manufactured with preproduction Kevlar 49 (Hamstad, 1979) were published. This preproduction fiber was called PRD 49 III. This report updates the continuing study to 10-year data and also presents 7.5-year data for spherical pressure vessels wound with production Kevlar 49. For completeness, this report will again describe the specimens of the original study with PRD 49 as well as specimens for the new study with Kevlar 49.

  7. Surface grafting of Kevlar fibers for improved interfacial properties of fiber-reinforced composites

    SciTech Connect

    Ravichandran, Vasudha.

    1991-01-01

    Matrix-specific chemical modification of the Kevlar fiber surfaces was carried out with the aim of enhancing adhesion, through covalent bonding, to selected thermoset matrix resins such as vinyl ester, unsaturated polyester and epoxy. A two-step grafting method, involving initial metalation followed by subsequent substitution, was used to graft vinyl and epoxy terminated groups onto Kevlar fiber surfaces. The physical changes in fiber surface were characterized by scanning-electron microscopy and surface area measurement and the chemical changes due to grafting were measured by contact angle measurement and neutron activation analysis; high concentrations of double bonds and epoxy groups were measured. The change in interfacial sear strength due to the surface grafting was measured by means of a single fiber pull out test. The results show a nearly twofold increase in the interfacial shear strength due to vinyl terminated grafts in the case of Kevlar/vinyl ester and Kevlar/polyester composites. Kevlar fibers containing the epoxy functionality on the surface had enhanced adhesion to epoxy matrix resin.

  8. Interfacial shear stress distribution in model composites. I - A Kevlar 49 fibre in an epoxy matrix

    SciTech Connect

    Jahankhani, H.; Galiotis, C. )

    1991-05-01

    The technique of Laser Raman Spectroscopy has been applied in the study of aramid fibers, such as Kevlar 49, and aramid/epoxy interfaces. A linear relationship has been found between Raman frequencies and strain upon loading a single Kevlar 49 filament in air. Model composites of single Kevlar 49 fibers embedded in epoxy resins have been fabricated and subjected to various degrees of mechanical deformation. The transfer lengths for reinforcement have been measured at various levels of applied tensile load and the dependence of transfer length upon applied matrix strain has been established. Finally, by balancing the tensile and the shear forces acting along the interface, the interfacial shear stress (ISS) distribution along the embedded fiber was obtained. 52 refs.

  9. Flight service evaluation of Kevlar-49 epoxy composite panels in wide-bodied commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    Stone, R. H.

    1984-01-01

    Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after 10 years of service. There are six Kevlar-49 panels on each aircraft: a left-hand and right-hand set of a wing-body sandwich fairing; a solid laminate under-wing fillet panel; and a 422 K (300 F) service aft engine fairing. The three L-1011s include one each in service with Eastern, Air Canada, and TWA. The fairings have accumulated a total of 79,568 hours, with one ship set having nearly 28,000 hours service. The inspections were conducted at the airlines' major maintenance bases with the participation of Lockheed Engineering. The Kevlar-49 components were found to be performing satisfactorily in service with no major problems, or any condition requiring corrective action. The only defects noted were minor impact damage, a few minor disbonds and a minor degree of fastener hole fraying and elongation. These are for the most part comparable to damage noted on fiberglass fairings. The service history obtained in this program indicates that Kevlar-49 epoxy composite materials have satisfactory service characteristics for use in aircraft secondary structure.

  10. Railgun Application for High Energy Impact Testing of Nano-Reinforced Kevlar-Based Composite Materials

    NASA Astrophysics Data System (ADS)

    Micheli, D.; Vricella, A.; Pastore, R.; Morles, R. B.; Marchetti, M.

    2013-08-01

    An advanced electromagnetic accelerator, called railgun, has been assembled and tuned in order to perform high energy impact test on layered structures. Different types of layered composite materials have been manufactured and characterized in terms of energy absorbing capability upon impact of metallic bullets fired at high velocity. The composite materials under testing are manufactured by integrating several layers of Kevlar fabric and carbon fiber ply within a polymeric matrix reinforced by carbon nanotubes at 1% of weight percentage. The experimental results show that the railgun-device is a good candidate to perform impact testing of materials in the space debris energy range, and that carbon nanotubes may enhance, when suitably coupled to the composite's matrix, the excellent antiballistic properties of the Kevlar fabrics.

  11. Effect of chemical treatment of Kevlar fibers on mechanical interfacial properties of composites.

    PubMed

    Park, Soo-Jin; Seo, Min-Kang; Ma, Tae-Jun; Lee, Douk-Rae

    2002-08-01

    In this work, the effects of chemical treatment on Kevlar 29 fibers have been studied in a composite system. The surface characteristics of Kevlar 29 fibers were characterized by pH, acid-base value, X-ray photoelectron spectroscopy (XPS), and FT-IR. The mechanical interfacial properties of the final composites were studied by interlaminar shear strength (ILSS), critical stress intensity factor (K(IC)), and specific fracture energy (G(IC)). Also, impact properties of the composites were investigated in the context of differentiating between initiation and propagation energies and ductile index (DI) along with maximum force and total energy. As a result, it was found that chemical treatment with phosphoric acid solution significantly affected the degree of adhesion at interfaces between fibers and resin matrix, resulting in improved mechanical interfacial strength in the composites. This was probably due to the presence of chemical polar groups on Kevlar surfaces, leading to an increment of interfacial binding force between fibers and matrix in a composite system. PMID:16290785

  12. Tensile and fatigue strength properties of Kevlar 29 aramid/epoxy unidirectional composites

    SciTech Connect

    Zweben, C.

    1981-07-22

    Static and fatigue tensile strength properties of filament wound undirectional Kevlar 29/epoxy, typical of filament wound material used in flywheel rotors, were studied. Machining techniques were developed to minimize fiber fuzzing on edges. The static modulus, normalized to 70% fiber volume fraction is 8.87 x 10/sup 6/ psi. The major Poisson's ratio is 0.37. The static composite tensile strength, normalized to 70% fiber volume fraction is 200 x 10/sup 3/ psi, corresponding to a fiber stress at failure of 286 x 10/sup 3/ psi, which is good for materials having a very high fiber volume fraction. The S-N curve for R = 0.7 was found to be quite flat. Although the techniques used in this program had previously been employed successfully to study the fatigue behavior of Kevlar 29/epoxy and Kevlar 49/epoxy unidirectional materials, we were unable to overcome the persistent problem of cohesive material failure in the tab regions. The apparent reason for this is the very low interlaminar shear strength of the filament wound material. 16 figures.

  13. Vacuum infusion manufacturing and experimental characterization of Kevlar/epoxy composites

    SciTech Connect

    Ricciardi, M. R.; Giordano, M.; Antonucci, V.; Langella, A.; Nele, L.

    2014-05-15

    Epoxy/Kevlar composites have been manufactured by conventional Vacuum Infusion process and the Pulse Infusion technique. Pulse Infusion allows to control the pressure of the vacuum bag on the dry fiber reinforcement by using a proper designed pressure distributor that induces a pulsed transverse action and promotes the through thickness resin flow. The realized composite panel have been mechanically characterized by performing tensile and short beam shear tests according with the ASTM D3039 and ASTM D2344/D 2344M standard respectively in order to investigate the effect of Pulse Infusion on the tensile strength and ILSS.

  14. Kevlar/PMR-15 polyimide matrix composite for a complex shaped DC-9 drag reduction fairing

    NASA Technical Reports Server (NTRS)

    Kawai, R. T.; Mccarthy, R. F.; Willer, M. S.; Hrach, F. J.

    1982-01-01

    The Aircraft Energy Efficiency (ACEE) Program was established by NASA to improve the fuel efficiency of commercial transport aircraft and thereby to reduce the amount of fuel consumed by the air transportation industry. One of the final items developed by the program is an improved fairing which is the aft closure for the thrust reverser actuators on the JT8D nacelles on DC-9 aircraft. The reduced-drag fairing uses, in the interest of weight savings, an advanced composite construction. The composite material contains Kevlar 49 fibers in a PMR-15 matrix. Attention is given to the aerodynamic configuration, the material system, and aspects of fabrication development.

  15. The Influence of impact on Composite Armour System Kevlar-29/polyester-Al2O3

    NASA Astrophysics Data System (ADS)

    Ramadhan, A. A.; Abu Talib, A. R.; Mohd Rafie, A. S.; Zahari, R.

    2012-09-01

    An experimental investigation of high velocity impact responses of composite laminated plates using a helium gas gun has been presented in this paper. The aim of this study was to develop the novel composite structure that meets the specific requirements of ballistic resistance which used for body protections, vehicles and other applications. Thus the high velocity impact tests were performed on composite Kevlar-29 fiber/polyester resin with alumina powder (Al2O3). The impact test was conducted by using a cylindrical steel projectile of 7.62mm diameter at a velocity range of 160-400 m/s. The results (shown in this work) are in terms of varying plate thickness and the amount of energy absorbed by the laminated plates meanwhile we obtained that the 12mm thickness of composite plate suitable for impact loading up to 200m/s impact velocity. Therefore this composite structure (it is used to reduce the amount of Kevlar) considered most economical armoure products. We used the ANSYS AUTODYN 3D- v.12 software for our simulations. The results have been obtained a4.1% maximum errors with experimental work of energy absorption.

  16. The Effect of Rheological Parameters on the Ballistic Properties of Shear Thickening Fluid (STF)-Kevlar Composites

    NASA Astrophysics Data System (ADS)

    Wetzel, Eric D.; Lee, Y. S.; Egres, R. G.; Kirkwood, K. M.; Kirkwood, J. E.; Wagner, N. J.

    2004-06-01

    The addition of colloidal shear thickening fluids (STFs) to Kevlar fabrics has been shown to enhance the ballistic penetration resistance of the fabric, under conditions of low velocities and small target sizes. It is believed that this improvement in ballistic properties is related to the resistance of the STF to deformation at high strain rates, since the addition of Newtonian fluids to Kevlar fabric does not improve ballistic performance. However, the precise role of the STF, and its rheological properties, in the ballistic defeat process are not known. In this study, ballistic and rheological experiments are performed to determine the effect of fluid viscosity, particle loadings, and particle size and shape on the behavior of STF-Kevlar composites. These results will be help to determine which rheological parameters are most critical to achieving enhanced composite properties.

  17. Considerations for acoustic emission monitoring of spherical Kevlar/epoxy composite pressure vessels

    NASA Technical Reports Server (NTRS)

    Hamstad, M. A.; Patterson, R. G.

    1977-01-01

    We are continuing to research the applications of acoustic emission testing for predicting burst pressure of filament-wound Kevlar 49/epoxy pressure vessels. This study has focused on three specific areas. The first area involves development of an experimental technique and the proper instrumentation to measure the energy given off by the acoustic emission transducer per acoustic emission burst. The second area concerns the design of a test fixture in which to mount the composite vessel so that the acoustic emission transducers are held against the outer surface of the composite. Included in this study area is the calibration of the entire test setup including couplant, transducer, electronics, and the instrument measuring the energy per burst. In the third and final area of this study, we consider the number, location, and sensitivity of the acoustic emission transducers used for proof testing composite pressure vessels.

  18. Tissue biocompatibility of kevlar aramid fibers and polymethylmethacrylate, composites in rabbits.

    PubMed

    Henderson, J D; Mullarky, R H; Ryan, D E

    1987-01-01

    Two groups of female NZW rabbits were implanted in the paravertebral muscles with aramid (du Pont Kevlar aramid 49) fibers and aramid-polymethylmethacrylate (PMMA) composites for 14 and 28 days. Rabbits were killed at these times periods, necropsies performed, sites scored for gross tissue response, and tissue specimens containing the implants removed for histopathological evaluation. A mild fibrous tissue reaction was observed around all implants containing aramid fiber similar to that observed around the silicone control implant. Some foreign body giant cells were also present adjacent to the fibers. An intense necrotic inflammatory reaction was present around the positive control material (PVC Y-78). The tissue response to implantation of aramid fiber and fiber-PMMA composites indicates that aramid is a biocompatible material. PMID:3558440

  19. An investigation of the compressive strength of Kevlar 49/epoxy composites

    NASA Technical Reports Server (NTRS)

    Kulkarni, S. V.; Rosen, B. W.; Rice, J. S.

    1975-01-01

    Tests were performed to evaluate the effect of a wide range of variables including matrix properties, interface properties, fiber prestressing, secondary reinforcement, and others on the ultimate compressive strength of Kevlar 49/epoxy composites. Scanning electron microscopy is used to assess the resulting failure surfaces. In addition, a theoretical study is conducted to determine the influence of fiber anisotropy and lack of perfect bond between fiber and matrix on the shear mode microbuckling. The experimental evaluation of the effect of various constituent and process characteristics on the behavior of these unidirectional composites in compression did not reveal any substantial increase in strength. However, theoretical evaluations indicate that the high degree of fiber anisotropy results in a significant drop in the predicted stress level for internal instability. Scanning electron microscope data analysis suggests that internal fiber failure and smooth surface debonding could be responsible for the measured low compressive strengths.

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

    PubMed Central

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

    2014-01-01

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

  1. Use of Acoustic Emission to Monitor Progressive Damage Accumulation in Kevlar (R) 49 Composites

    NASA Technical Reports Server (NTRS)

    Waller, Jess M.; Saulsberry, Regor L.; Andrade, Eduardo

    2009-01-01

    Acoustic emission (AE) data acquired during intermittent load hold tensile testing of epoxy impregnated Kevlar(Registeres TradeMark) 49 (K/Ep) composite strands were analyzed to monitor progressive damage during the approach to tensile failure. Insight into the progressive damage of K/Ep strands was gained by monitoring AE event rate and energy. Source location based on energy attenuation and arrival time data was used to discern between significant AE attributable to microstructural damage and spurious AE attributable to noise. One of the significant findings was the observation of increasing violation of the Kaiser effect (Felicity ratio < 1.0) with damage accumulation. The efficacy of three different intermittent load hold stress schedules that allowed the Felicity ratio to be determined analytically is discussed.

  2. Flight service evaluation of kevlar-49 epoxy composite panels in wide-bodied commercial transport aircraft: Flight service report

    NASA Technical Reports Server (NTRS)

    Stone, R. H.

    1981-01-01

    Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after 7 years service. There are six Kevlar-49 panels on each aircraft: a left hand and right hand set of a wing-body sandwich fairing; a slid laminate under-wing fillet panel; and a 422 K service aft engine fairing. The three L-1011s include one each in service with Eastern, Air Canada, and TWA. The fairings have accumulated a total of 52,500 hours, with one ship set having 17.700 hours service. The inspections were conducted at the airlines' major maintenance bases with the participation of Lockheed Engineering. The Kevlar-49 components were found to be performing satisfactorily in service with no major problems or any condition requiring corrective action. The only defects noted were minor impact damage and a minor degree of fastener hole fraying and elongation. These are for the most part comparable to damage noted on fiberglass fairings. The service history to date indicates that Kevlar-49 epoxy composite materials have satisfactory service characteristics for use in aircraft secondary structure.

  3. In-Situ NDE Characterization of Kevlar and Carbon Composite Micromechanics for Improved COPV Health Monitoring

    NASA Technical Reports Server (NTRS)

    Waller, Jess M.; Saulsberry, Regor L.

    2009-01-01

    This project is a subtask of a multi-center project to advance the state-of-the-art by developing NDE techniques that are capable of evaluating stress rupture (SR) degradation in Kevlar/epoxy (K/Ep) composite overwrapped pressure vessels (COPVs), and damage progression in carbon/epoxy (C/Ep) COPVs. In this subtask, acoustic emission (AE) data acquired during intermittent load hold tensile testing of K/Ep and C/Ep composite tow materials-of-construction used in COPV fabrication were analyzed to monitor progressive damage during the approach to tensile failure. Insight into the progressive damage of composite tow was gained by monitoring AE event rate, energy, source location, and frequency. Source location based on arrival time data was used to discern between significant AE attributable to microstructural damage and spurious AE attributable to background and grip noise. One of the significant findings was the observation of increasing violation of the Kaiser effect (Felicity ratio < 1.0) with damage accumulation.

  4. Influence of weave structures on the tribological properties of hybrid Kevlar/PTFE fabric composites

    NASA Astrophysics Data System (ADS)

    Gu, Dapeng; Yang, Yulin; Qi, Xiaowen; Deng, Wei; Shi, Lei

    2012-09-01

    The existing research of the woven fabric self-lubricating liner mainly focus on the tribological performance improvements and the service life raised by changing different fiber type combinations, adding additive modification, and performing fiber surface modification. As fabric composites, the weave structures play an important role in the mechanical and tribological performances of the liners. However, hardly any literature is available on the friction and wear behavior of such composites with different weave structures. In this paper, three weave structures (plain, twill 1/3 and satin 8/5) of hybrid Kevlar/PTFE fabric composites are selected and pin-on-flat linear reciprocating wear studies are done on a CETR tester under different pressures and different frequencies. The relationship between the tensile strength and the wear performance are studied. The morphologies of the worn surfaces under the typical test conditions are analyzed by means of scanning electron microscopy (SEM). The analysis results show that at 10 MPa, satin 8/5 performs the best in friction-reduction and antiwear performance, and plain is the worst. At 30 MPa, however, the antiwear performance is reversed and satin 8/5 does not even complete the 2 h wear test at 16 Hz. There is no clear evidence proving that the tensile strength has an influence on the wear performance. So the different tribological performance of the three weave structures of fabric composites may be attributed to the different PTFE proportions in the fabric surface and the different wear mechanisms. The fabric composites are divided into three regions: the lubrication region, the reinforced region and the bonding region. The major mechanisms are fatigue wear and the shear effects of the friction force in the lubrication region. In the reinforced region fiber-matrix de-bonding and fiber breakage are involved. The proposed research proposes a regional wear model and further indicates the wear process and the wear mechanism

  5. Flight service evaluation of Kevlar-49 epoxy composite panels in wide-bodied commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    Stone, R. H.

    1980-01-01

    Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after 6 years' service. The Kevlar-49 components were found to be performing satisfactorily in service with no major problems, or any condition requiring corrective action. The only defects noted were minor impact damage, and a minor degree of fastener hole fraying and elongation. These are for the most part comparable to damage noted on fiberglass fairings.

  6. Flight service evaluation of Kevlar-49 epoxy composite panels in wide-bodied commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    Stone, R. H.

    1979-01-01

    Kevlar-49 fairing panels, installed as flight service components on three L-1011s, were inspected after five years' service. There are six Kevlar-49 panels on each aircraft: a left-hand and right-hand set of a wing-body sandwich fairing; a solid laminate under-wing fillet panel; and a 150 C (300 F) service aft engine fairing. The fairings have accumulated a total of 40,534 hours, with one ship set having 16,091 hours service as of Feb. 11, 1979. The Kevlar-49 components were found to be performing satisfactorily in service with no major problems, or any condition requiring corrective action. The only defects noted were minor impact damage, and a minor degree of fastener hole fraying and elongation. These are for the most part comparable to damage noted on fiberglass fairings.

  7. Improvement of interfacial adhesion and nondestructive damage evaluation for plasma-treated PBO and Kevlar fibers/epoxy composites using micromechanical techniques and surface wettability.

    PubMed

    Park, Joung-Man; Kim, Dae-Sik; Kim, Sung-Ryong

    2003-08-15

    Comparison of interfacial properties and microfailure mechanisms of oxygen-plasma treated poly(p-phenylene-2,6-benzobisoxazole (PBO, Zylon) and poly(p-phenylene terephthalamide) (PPTA, Kevlar) fibers/epoxy composites were investigated using a micromechanical technique and nondestructive acoustic emission (AE). The interfacial shear strength (IFSS) and work of adhesion, Wa, of PBO or Kevlar fiber/epoxy composites increased with oxygen-plasma treatment, due to induced hydrogen and covalent bondings at their interface. Plasma-treated Kevlar fiber showed the maximum critical surface tension and polar term, whereas the untreated PBO fiber showed the minimum values. The work of adhesion and the polar term were proportional to the IFSS directly for both PBO and Kevlar fibers. The microfibril fracture pattern of two plasma-treated fibers appeared obviously. Unlike in slow cooling, in rapid cooling, case kink band and kicking in PBO fiber appeared, whereas buckling in the Kevlar fiber was observed mainly due to compressive and residual stresses. Based on the propagation of microfibril failure toward the core region, the number of AE events for plasma-treated PBO and Kevlar fibers increased significantly compared to the untreated case. The results of nondestructive AE were consistent with microfailure modes. PMID:16256662

  8. Evaluation of Acoustic Emission NDE of Kevlar Composite Over Wrapped Pressure Vessels

    NASA Technical Reports Server (NTRS)

    Horne, Michael R.; Madaras, Eric I.

    2008-01-01

    Pressurization and failure tests of small Kevlar/epoxy COPV bottles were conducted during 2006 and 2007 by Texas Research Institute Austin, Inc., at TRI facilities. This is a report of the analysis of the Acoustic Emission (AE) data collected during those tests. Results of some of the tests indicate a possibility that AE can be used to track the stress-rupture degradation of COPV vessels.

  9. Characterization of Kevlar Using Raman Spectroscopy

    NASA Technical Reports Server (NTRS)

    Washer, Glenn; Brooks, Thomas; Saulsberry, Regor

    2007-01-01

    This paper explores the characterization of Kevlar composite materials using Raman spectroscopy. The goal of the research is to develop and understand the Raman spectrum of Kevlar materials to provide a foundation for the development of nondestructive evaluation (NDE) technologies based on the interaction of laser light with the polymer Kevlar. The paper discusses the fundamental aspects of experimental characterization of the spectrum of Kevlar, including the effects of incident wavelength, polarization and laser power. The effects of environmental exposure of Kevlar materials on certain characteristics of its Raman spectrum are explored, as well as the effects of applied stress. This data may provide a foundation for the development of NDE technologies intended to detect the in-situ deterioration of Kevlar materials used for engineering applications that can later be extended to other materials such as carbon fiber composites.

  10. Evaluation of Material Models within LS-DYNA(Registered TradeMark) for a Kevlar/Epoxy Composite Honeycomb

    NASA Technical Reports Server (NTRS)

    Polanco, Michael A.; Kellas, Sotiris; Jackson, Karen

    2009-01-01

    The performance of material models to simulate a novel composite honeycomb Deployable Energy Absorber (DEA) was evaluated using the nonlinear explicit dynamic finite element code LS-DYNA(Registered TradeMark). Prototypes of the DEA concept were manufactured using a Kevlar/Epoxy composite material in which the fibers are oriented at +/-45 degrees with respect to the loading axis. The development of the DEA has included laboratory tests at subcomponent and component levels such as three-point bend testing of single hexagonal cells, dynamic crush testing of single multi-cell components, and impact testing of a full-scale fuselage section fitted with a system of DEA components onto multi-terrain environments. Due to the thin nature of the cell walls, the DEA was modeled using shell elements. In an attempt to simulate the dynamic response of the DEA, it was first represented using *MAT_LAMINATED_COMPOSITE_FABRIC, or *MAT_58, in LS-DYNA. Values for each parameter within the material model were generated such that an in-plane isotropic configuration for the DEA material was assumed. Analytical predictions showed that the load-deflection behavior of a single-cell during three-point bending was within the range of test data, but predicted the DEA crush response to be very stiff. In addition, a *MAT_PIECEWISE_LINEAR_PLASTICITY, or *MAT_24, material model in LS-DYNA was developed, which represented the Kevlar/Epoxy composite as an isotropic elastic-plastic material with input from +/-45 degrees tensile coupon data. The predicted crush response matched that of the test and localized folding patterns of the DEA were captured under compression, but the model failed to predict the single-cell three-point bending response.

  11. Experimental determinations of the eigenmodes for composite bars made with carbon and Kevlar-carbon fibers

    NASA Astrophysics Data System (ADS)

    Miriţoiu, C. M.; Stănescu, M. M.; Burada, C. O.; Bolcu, D.; Roşca, V.

    2015-11-01

    For modal identification, the single-point excitation method has been widely used in modal tests and it consists in applying a force in a given point and recording the vibratory structure response in all interest points, including the excitation point. There will be presented the experimental recordings for the studied bars (with Kevlar-carbon or carbon fibers), the frequency response function in Cartesian and polar coordinates. By using the frequency response functions we determine the eigenparameters for each bar. We present the final panel of the eigenmodes (with the damping factors, eigenfrequencies and critical damping) for each considered bar. Using the eigenfrequency of the first determined eigenmode, the bars stiffness has been determined. The presented bars can be used in practical engineering for: car or bus body parts, planes body parts, bullet-proof vests, reinforcements for sandwich beams, and so on.

  12. Kevlar fiber-epoxy adhesion and its effect on composite mechanical and fracture properties by plasma and chemical treatment

    SciTech Connect

    Shyu, S.S.; Wu, S.R.; Sheu, G.S.

    1996-12-31

    Kevlar 49 fibers were surface modified by gas (ammonia, oxygen, and water vapor) plasmas etching and chlorosulfonation and subsequent reaction with some reagents (glycine, deionized water, ethylenediamine, and 1-butanol) to improve the adhesion to epoxy resin. After these treatments, the changes in fiber topography, chemical compositions of the fiber surfaces and the surface functional groups introduced to the surface of fibers were identified by SEM XPS and static SIMS. Interlaminar shear strength (ILSS) and T-peel strength between the fiber and epoxy resin were markedly improved by gas plasma and chlorosulfonation (0.1% and 0.25% ClSO{sub 3}H at 30 s). However, it is clear from the similar G{sub IC} values of the treated and untreated fiber composites that the fiber/matrix interfacial bond strength is only a minor contributor to G{sub IC}. SEM was also used to study the surface topography of the fracture surfaces of composites in T-peel test.

  13. Etude comparative sur la propagation de l'endommagement apres impact des composites carbone/epoxy renforces par piquage au fil Kevlar et titane-nickel

    NASA Astrophysics Data System (ADS)

    Vachon, Pierre-Luc

    Composite laminates have strong in-plane mechanical properties, but they are generally weaker through their thickness. This specificity makes the laminates prone to delamination, particularly under low-velocity impact loads. Consequently numerous research efforts have been dedicated to developing interlaminar reinforcing methods, such as transverse stitching. The present project proposes the use of the stitching technique combined with a special stitching thread made of superelastic TiNi alloy. This technology is intended to improve the delamination toughness in composite laminates loaded in bending. In the first part of this study a numerical model was developed for analyzing composite structures. The 3-D finite element model was built with the ANSYS commercial software using 20-node solid and 8-node shell elements. The progressive damage modeling technique was used, allowing the prediction of delamination propagation in a laminate submitted to various loading modes. The model was validated for a plate under quasi-static traction load, and it was then used to simulate three-point bending tests. Secondly, carbon/epoxy composite panels were fabricated, with each panel containing unstitched and stitched specimens. Two different materials were used for the stitching thread: superelastic TiNi wires and Kevlar threads as a reference. Some stitched specimens were cut in slices in order to make some observations of the internal stitch using an optical microscope. Standardized low-velocity impact tests and compression after impact tests were carried out on stitched and unstitched specimens (ASTM D7136 and D7137). The Kevlar reinforcements have shown great performance in reducing the delaminated zone after impact, as well as in improving the residual compression strength. The TiNi reinforcements provided encouraging results during the impact tests, though being less effective than the Kevlar threads. During the compression after impact tests, only a slight difference could

  14. Composite Stress Rupture NDE Research and Development Project (Kevlar[R] and Carbon)

    NASA Technical Reports Server (NTRS)

    Saulsberry, Regor

    2010-01-01

    The objective was to develop and demonstrate nondestructive evaluation (NDE) techniques capable of assessing stress rupture related strength degradation for carbon composite pressure vessels, either in a structural health monitoring (SHM) or periodic inspection mode.

  15. Power generation from base excitation of a Kevlar composite beam with ZnO nanowires

    NASA Astrophysics Data System (ADS)

    Malakooti, Mohammad H.; Hwang, Hyun-Sik; Sodano, Henry A.

    2015-04-01

    One-dimensional nanostructures such as nanowires, nanorods, and nanotubes with piezoelectric properties have gained interest in the fabrication of small scale power harvesting systems. However, the practical applications of the nanoscale materials in structures with true mechanical strengths have not yet been demonstrated. In this paper, piezoelectric ZnO nanowires are integrated into the fiber reinforced polymer composites serving as an active phase to convert the induced strain energy from ambient vibration into electrical energy. Arrays of ZnO nanowires are grown vertically aligned on aramid fibers through a low-cost hydrothermal process. The modified fabrics with ZnO nanowires whiskers are then placed between two carbon fabrics as the top and the bottom electrodes. Finally, vacuum resin transfer molding technique is utilized to fabricate these multiscale composites. The fabricated composites are subjected to a base excitation using a shaker to generate charge due to the direct piezoelectric effect of ZnO nanowires. Measuring the generated potential difference between the two electrodes showed the energy harvesting application of these multiscale composites in addition to their superior mechanical properties. These results propose a new generation of power harvesting systems with enhanced mechanical properties.

  16. Low cost tooling material and process for graphite and Kevlar composites

    NASA Technical Reports Server (NTRS)

    Childs, William I.

    1987-01-01

    An Extruded Sheet Tooling Compound (ESTC) was developed for use in quickly building low cost molds for fabricating composites. The ESTC is a very highly mineral-filled resin system formed into a 6 mm thick sheet. The sheet is laid on the pattern, vacuum (bag) is applied to remove air from the pattern surface, and the assembly is heat cured. The formed ESTC is then backed and/or framed and ready for use. The cured ESTC exhibits low coefficient of thermal expansion and maintains strength at temperatures of 180 to 200 C. Tools were made and used successfully for: Compression molding of high strength epoxy sheet molding compound, stamping of aluminum, resin transfer molding of polyester, and liquid resin molding of polyester. Several variations of ESTC can be made for specific requirements. Higher thermal conductivity can be achieved by using an aluminum particle filler. Room temperature gel is possible to allow use of foam patterns.

  17. Low cost tooling material and process for graphite and Kevlar composites. Final report

    SciTech Connect

    Childs, W.I.

    1987-06-01

    An Extruded Sheet Tooling Compound (ESTC) was developed for use in quickly building low cost molds for fabricating composites. The ESTC is a very highly mineral-filled resin system formed into a 6 mm thick sheet. The sheet is laid on the pattern, vacuum (bag) is applied to remove air from the pattern surface, and the assembly is heat cured. The formed ESTC is then backed and/or framed and ready for use. The cured ESTC exhibits low coefficient of thermal expansion and maintains strength at temperatures of 180 to 200 C. Tools were made and used successfully for: Compression molding of high strength epoxy sheet molding compound, stamping of aluminum, resin transfer molding of polyester, and liquid resin molding of polyester. Several variations of ESTC can be made for specific requirements. Higher thermal conductivity can be achieved by using an aluminum particle filler. Room temperature gel is possible to allow use of foam patterns.

  18. 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.

  19. In-Situ Nondestructive Evaluation of Kevlar(Registered Trademark)and Carbon Fiber Reinforced Composite Micromechanics for Improved Composite Overwrapped Pressure Vessel Health Monitoring

    NASA Technical Reports Server (NTRS)

    Waller, Jess; Saulsberry, Regor

    2012-01-01

    NASA has been faced with recertification and life extension issues for epoxy-impregnated Kevlar 49 (K/Ep) and carbon (C/Ep) composite overwrapped pressure vessels (COPVs) used in various systems on the Space Shuttle and International Space Station, respectively. Each COPV has varying criticality, damage and repair histories, time at pressure, and pressure cycles. COPVs are of particular concern due to the insidious and catastrophic burst-before-leak failure mode caused by stress rupture (SR) of the composite overwrap. SR life has been defined [1] as the minimum time during which the composite maintains structural integrity considering the combined effects of stress level(s), time at stress level(s), and associated environment. SR has none of the features of predictability associated with metal pressure vessels, such as crack geometry, growth rate and size, or other features that lend themselves to nondestructive evaluation (NDE). In essence, the variability or surprise factor associated with SR cannot be eliminated. C/Ep COPVs are also susceptible to impact damage that can lead to reduced burst pressure even when the amount of damage to the COPV is below the visual detection threshold [2], thus necessitating implementation of a mechanical damage control plan [1]. Last, COPVs can also fail prematurely due to material or design noncompliance. In each case (SR, impact or noncompliance), out-of-family behavior is expected leading to a higher probability of failure at a given stress, hence, greater uncertainty in performance. For these reasons, NASA has been actively engaged in research to develop NDE methods that can be used during post-manufacture qualification, in-service inspection, and in-situ structural health monitoring. Acoustic emission (AE) is one of the more promising NDE techniques for detecting and monitoring, in real-time, the strain energy release and corresponding stress-wave propagation produced by actively growing flaws and defects in composite

  20. Lightweight engine containment. [Kevlar shielding

    NASA Technical Reports Server (NTRS)

    Weaver, A. T.

    1977-01-01

    Kevlar fabric styles and weaves were studied, as well as methods of application for advanced gas turbine engines. The Kevlar material was subjected to high speed impacts by simple projectiles fired from a rifle, as well as more complex shapes such as fan blades released from gas turbine rotors in a spin pit. Just contained data was developed for a variety of weave and/or application techniques, and a comparative containment weight efficiency was established for Kevlar containment applications. The data generated during these tests is being incorporated into an analytical design system so that blade containment trade-off studies between Kevlar and metal case engine structures can be made. Laboratory tests and engine environment tests were performed to determine the survivability of Kevlar in a gas turbine environment.

  1. Study on mechanical properties and damage behaviors of Kevlar fiber reinforced epoxy composites by digital image correlation technique under optical microscope

    NASA Astrophysics Data System (ADS)

    Gao, Xiang; Shao, Wenquan; Ji, Hongwei

    2010-10-01

    Kevlar fiber-reinforced epoxy (KFRE) composites are widely used in the fields of aerospace, weapon, shipping, and civil industry, due to their outstanding capabilities. In this paper, mechanical properties and damage behaviors of KFRE laminate (02/902) were tested and studied under tension condition. To precisely measure the tensile mechanical properties of the material and investigate its micro-scale damage evolution, a micro-image measuring system with in-situ tensile device was designed. The measuring system, by which the in-situ tensile test can be carried out and surface morphology evolution of the tensile specimen can be visually monitored and recorded during the process of loading, includes an ultra-long working distance zoom microscope and a in-situ tensile loading device. In this study, a digital image correlation method (DICM) was used to calculate the deformation of the tensile specimen under different load levels according to the temporal series images captured by an optical microscope and CCD camera. Then, the elastic modulus and Poisson's ratio of the KFRE was obtained accordingly. The damage progresses of the KFRE laminates were analyzed. Experimental results indicated that: (1) the KFRE laminate (02/902) is almost elastic, its failure mode is brittle tensile fracture.(2) Mechanical properties parameters of the material are as follows: elastic modulus is 14- 16GPa, and tensile ultimate stress is 450-480 Mpa respectively. (3) The damage evolution of the material is that cracks appear in epoxy matrix firstly, then, with the increasing of the tensile loading, matrix cracks add up and extend along a 45° angle direction with tensile load. Furthermore, decohesion between matrix and fibers as well as delamination occurs. Eventually, fibers break and the material is damaged.

  2. Robust Tensioned Kevlar Suspension Design

    NASA Technical Reports Server (NTRS)

    Young, Joseph B.; Naylor, Bret J.; Holmes, Warren A.

    2012-01-01

    One common but challenging problem in cryogenic engineering is to produce a mount that has excellent thermal isolation but is also rigid. Such mounts can be achieved by suspending the load from a network of fibers or strings held in tension. Kevlar fibers are often used for this purpose owing to their high strength and low thermal conductivity. A suite of compact design elements has been developed to improve the reliability of suspension systems made of Kevlar.

  3. Aging studies of Kevlar 49 fibers

    SciTech Connect

    Morgan, R.J.; Pruneda, C.O.; Kong, F.M.

    1983-11-01

    The aging mechanisms in service environment of Kevlar 49 fibers, E.I. duPont, (poly(p-phenylene)terephthalamide) are reviewed. The principal aging mechanisms considered are (i) u.v.-, (ii) hydrolytic- and (iii) stress-induced macromolecular chain scission and microvoid growth. U.V.-induced strength degradation can be significant as a result of photo-oxidative and photodegradative radical formation but in Kevlar 49-epoxy composites only the exterior yarn layer is deteriorated. Hydrolytic chain scission of the amide linkage and corresponding fiber strength deterioration is considered in terms of R.H., time, temperature and stress level. The rates of hydrolytic degradation at 100% R.H. in the 100 to 200/sup 0/C range are reported. The estimated rates of fiber degradation in various service environment conditions are also reported and shown not to be serious. The stress-induced aging of Kevlar 49 fibers is considered in terms of the growth and coalescence of inherent microvoids along the fiber axis together with the generation of new microvoids. (These growth processes involve no detectable macromolecular chain scission or deterioration in fiber strength.) At a critical microvoid volume fraction catastrophic failure occurs by interconnection of such voids.

  4. Moisture dependence of positron lifetime in Kevlar-49

    NASA Technical Reports Server (NTRS)

    Singh, Jag J.; Holt, William H.; Mock, Willis, Jr.

    1984-01-01

    Because of filamentary character of Kevlar-49 aramid fibers, there is some concern about the moisture uptake and its effect on plastic composites reinforced with Kevlar-49 fibers. As part of continuing studies of positron lifetime in polymers, we have measured positron lifetime spectra in Kevlar-49 fibers as a function of their moisture content. The long lifetime component intensities are rather low, being only of the order of 2-3 percent. The measured values of long component lifetimes at various moisture levels in the specimens are as follows: 2072 +/- 173 ps (dry); 2013 +/- 193 ps (20.7 percent saturation); 1665 +/- 85 ps (25.7 percent saturation); 1745 +/- 257 ps (32.1 percent saturation); and 1772 +/- 217 ps (100 percent saturation). It is apparent that the long component lifetime at first decreases and then increases as the specimen moisture content increases. These results have been compared with those inferred from Epon-815 and Epon-815/K-49 composite data.

  5. Investigation of Kevlar fabric-based materials for use with inflatable structures

    NASA Technical Reports Server (NTRS)

    Niccum, R. J.; Munson, J. B.; Rueter, L. L.

    1977-01-01

    Design, manufacture and testing of laminated and coated composite materials incorporating a structural matrix of Kevlar are reported. The practicality of using Kevlar in aerostat materials is demonstrated, and data are provided on practical weaves, lamination and coating particulars, rigidity, strength, weight, elastic coefficients, abrasion resistance, crease effects, peel strength, blocking tendencies, helium permeability, and fabrication techniques. Properties of the Kevlar-based materials are compared with conventional Dacron-reinforced counterparts. A comprehensive test and qualification program is discussed, and considerable quantitative biaxial tensile and shear test data are provided.

  6. Ultrasonic analysis of Kevlar-epoxy filament wound structures

    NASA Astrophysics Data System (ADS)

    Brosey, W. D.

    1985-07-01

    Composite structures are often desirable for their strength and weight characteristics. Since composites are not as well characterized mechanically as metallic or ceramic structures, much work has been performed at the Oak Ridge Y-12 Plant to obtain that characterization and to develop methods of determining the mechanical properties of a composite nondestructively. Most of the work to date has been performed on nonenclosed structures. One notable exception has been the holographic evaluation of spherical Kevlar-epoxy composite pressure vessels. Several promising nondestructive evaluation techniques have been used to locate flaws and predict the integrity of the composite. Several of these include thermography, Moire interferometry, ultrasonic stress wave factor, ultrasonic C-scan image enhancement, radiography, and nuclear magnetic resonance. As a first step in this transfer and development of NDE techniques, known defects were placed within spherical Kevlar-epoxy, filament-wound test specimens to determine the extent to which they could be detected. These defects included Teflon shim-simulated delaminations, macrosphere-simulated voids, dry-band sets, variable tension, Kevlar 29 fiber instead of the higher strength Kevlar 40 fiber, and an alternate high-void-content winding pattern. Ultrasonic waveform analysis was performed in both the time and frequency domains to determine the detectability and locatability of structural flaws within the composite. Preparation has been made at Virginia Polytechnic Institute and State University and at the University of Delaware, to examine the specimens using various NDE techniques. This work is a compilation of interim project reports in partial fulfillment of the contracts between Virginia Polytechnic Institute and State University, the University of Delaware, and Y-12 Plant.

  7. Development of Kevlar parachute webbings

    SciTech Connect

    Ericksen, R.H.

    1991-01-01

    This paper describes the development of Kevlar webbings for parachute applications. Evaluation of existing webbings and a study of the effects of filling yarn denier and pick count on tensile and joint strength provided data for fabric design. Measurements of warp crimp as a function of filling denier and pick count demonstrated the relationship between warp crimp and strength. One newly developed webbing had higher strength efficiency and another had higher joint efficiency than comparable existing webbings. Both new webbings had overall efficiencies over 5% higher than values for existing webbings. 10 refs., 4 figs., 2 tabs.

  8. Investigation of Kevlar fabric based materials for use with inflatable structures

    NASA Technical Reports Server (NTRS)

    Niccum, R. J.; Munson, J. B.

    1974-01-01

    Design, manufacture and testing of laminated and coated composite materials incorporating a structural matrix of Kevlar are reported in detail. The practicality of using Kevlar in aerostat materials is demonstrated and data are provided on practical weaves, lamination and coating particulars, rigidity, strength, weight, elastic coefficients, abrasion resistance, crease effects, peel strength, blocking tendencies, helium permeability, and fabrication techniques. Properties of the Kevlar based materials are compared with conventional, Dacron reinforced counterparts. A comprehensive test and qualification program is discussed and quantitative biaxial tensile and shear test data are provided. The investigation shows that single ply laminates of Kevlar and plastic films offer significant strength to weight improvements, are less permeable than two ply coated materials, but have a lower flex life.

  9. Prestressed concrete using KEVLAR reinforced tendons

    SciTech Connect

    Dolan, C.W.

    1989-01-01

    KEVLAR is a high strength, high modulus synthetic fiber manufactured by the E.I. DuPont de Nemours Company. The fiber is resistant to chloride and alkali attack. The resistance is enhanced when the fibers are assembled into a resin matrix and fabricated as rods. These properties suggest that KEVLAR reinforced rods may be a substitute for high strength steel prestress tendons in certain applications such as bridge decks and parking structures. This dissertation presents the background, theoretical development, and experimental investigations of KEVLAR reinforced rod strength, anchorage, fabrication and performance in prestressed concrete structures. The study concludes that KEVLAR has significant potential for these prestressed concrete applications. However, the reliability of the long term anchorage of the KEVLAR reinforced rods must be improved before production applications are undertaken. KEVLAR has a low shear strength compared to its tensile capacity. The anchorage of KEVLAR reinforced rods is sensitive to the shear forces generated in the anchorage assembly. Finite element analyses, using interface elements to simulate the addition of a mold release agent in a conic anchor, predict the behavior of resin socketed anchors. Test results confirm that mold release agents reduce the anchor shear stresses and suggest that moderate strength resins may be used in the anchor. KEVLAR is nearly linearly elastic to failure, yet ductility of a structure is an important design concern. Prestressed concrete beam tests using both bonded and unbonded tendons demonstrated that ductile structural behavior is obtained. Methods of predicting the strength and deflection behavior of the prestressed beams are presented and the theoretical predictions are compared to the experimental results. The overall correlation between predicted and theoretical results is satisfactory.

  10. Use of LS-DYNA(Registered TradeMark) to Assess the Energy Absorption Performance of a Shell-Based Kevlar(TradeMark)/Epoxy Composite Honeycomb

    NASA Technical Reports Server (NTRS)

    Polanco, Michael

    2010-01-01

    The forward and vertical impact stability of a composite honeycomb Deployable Energy Absorber (DEA) was evaluated during a full-scale crash test of an MD-500 helicopter at NASA Langley?s Landing and Impact Research Facility. The lower skin of the helicopter was retrofitted with DEA components to protect the airframe subfloor upon impact and to mitigate loads transmitted to Anthropomorphic Test Device (ATD) occupants. To facilitate the design of the DEA for this test, an analytical study was conducted using LS-DYNA(Registered TradeMark) to evaluate the performance of a shell-based DEA incorporating different angular cell orientations as well as simultaneous vertical and forward impact conditions. By conducting this study, guidance was provided in obtaining an optimum design for the DEA that would dissipate the kinetic energy of the airframe while maintaining forward and vertical impact stability.

  11. Surface characterization of Kevlar fibers by FT-IR spectroscopy

    SciTech Connect

    Chatzi, E.G.

    1987-01-01

    The Kevlar-49 aramid fiber offers considerable potential for utilization in high-performance composite materials. However, it has poor adhesion to the polymer matrix resin. In order to improve the adhesion the surface of the fiber was characterized by using two nondestructive Fourier transform infrared (FT-IR) techniques. It was shown that the polymer chains in the skin are oriented parallel to the surface, while in the core they are almost radially oriented. This orientation as well as the fact that the functional groups are intermolecularly hydrogen-bonded might limit their availability for reacting with the polymer matrix. The author also characterized the water absorbed in both the skin and the core of the fiber and found the existence of three types of water: (a) weakly hydrogen-bonded between one NH and one carbonyl group, (b) between two carbonyl groups and (c) liquid-like water clustered in microvoids and other sites inside the fibers. It was also found that 30% of the NH groups of the Kevlar-49 fiber are accessible for deuterium exchange. These groups on one hand are available for reactions that would improve the adhesion, but on the other hand can hydrogen-bond with water, which would be detrimental for the mechanical properties of the composite.

  12. Bound water in Kevlar 49 fibers

    SciTech Connect

    Garza, R.G.; Pruneda, C.O.; Morgan, R.J.

    1981-04-01

    From elemental analyses, thermogravimetric-mass spectroscopy studies and re-evaluation of previous water diffusion studies in Kevlar 49 fibers it is concluded that these fibers can contain two types of sorbed moisture. The fibers can absorb up to approx. 6 wt % loosely bound water with an activation energy for outgassing by desorption of 6 kcal/mole. This loosely bound water is a direct result of the presence of Na/sub 2/SO/sub 4/ impurities and the perturbations they induce on the packing of the rod-like poly (p-phenylene terephthalamide) macromolecules. Kevlar 49 fibers also inherently contain up to 30 wt % additional water which is tightly bound within the crystal lattice. This water exhibits an activation energy for outgassing by diffusion of approx. 40 kcal/mole and is only evolved from the fiber in significant quantities at t > 350/sup 0/C over a period of hours.

  13. Thick-wall Kevlar 49/Epoxy pressure vessels

    SciTech Connect

    Guess, T.R.

    1984-01-01

    The feasibility of thick-wall composite vessels for very high pressure applications is demonstrated. Prototype vessels, in both spherical and cylindrical geometries, were designed, fabricated and burst tested. It is shown that experimental burst pressures are in excellent agreement with predicted values for burst pressures up to 60 ksi. Each unit consisted of a thin, seamless, copper liner with stainless steel fill stems and a filament-wound Kevlar 49/epoxy outer shell. Analysis of vessel performance accounted for liner thickness and yield strengths, composite thickness, mechanical properties and fiber volume fraction, and stress concentrations caused by the fill stem. Spherical vessels of three different sizes (inside diameters of 2.15 inches, 4.0 inches and 5.3 inches) with either 30 ksi or 60 ksi design burst pressure are discussed. Also, cylindrical vessels with identical liners but of two different composite thicknesses are described. These vessels achieved 50 ksi and 57 ksi burst pressures, respectively. In addition to the design considerations alluded to throughout the paper, the stress state in a thin metal liner during cyclic loading and the life prediction of composite vessels under sustained loading are discussed.

  14. Lifetimes statistics for single Kevlar 49 aramid filaments in creep-rupture at elevated temperatures

    SciTech Connect

    Wu, H.F.

    1987-01-01

    Kevlar 49 fibrous composites are routinely fabricated to have strengths above 1.5 GPa(200 ksi), but in many applications one would like to sustain such stresses for long time periods, sometimes at elevated temperatures. Thus the temperature dependence of the creep-rupture process in the fibers is of interest. Experimental data are presented for the lifetime of single Kevlar 49 filaments under constant stress at elevated temperatures. The goal of this research was to fully characterize the statistical strength and lifetime behavior of single filaments in order to separate fiber effects from fiber/matrix interactions in the creep-rupture lifetime of Kevlar 49/epoxy composites as described for example in Phoenix and Wu (1983). First we conducted experiments to determine distributions for the strength of filaments from the two distinct spools as a function of temperature. As expected, the data could generally be fitted by a two-parameter Weibull distribution. Lifetime experiments at 80 and 130/sup 0/C were conducted at several stress levels chosen as suitable fractions of the Weibull scale parameter for short-term strength for that temperature. The lifetime data were well modelled by a two-parameter Weibull distribution with large variability.

  15. Multiscale modeling of interwoven Kevlar fibers based on random walk to predict yarn structural response

    NASA Astrophysics Data System (ADS)

    Recchia, Stephen

    Kevlar is the most common high-end plastic filament yarn used in body armor, tire reinforcement, and wear resistant applications. Kevlar is a trade name for an aramid fiber. These are fibers in which the chain molecules are highly oriented along the fiber axis, so the strength of the chemical bond can be exploited. The bulk material is extruded into filaments that are bound together into yarn, which may be chorded with other materials as in car tires, woven into a fabric, or layered in an epoxy to make composite panels. The high tensile strength to low weight ratio makes this material ideal for designs that decrease weight and inertia, such as automobile tires, body panels, and body armor. For designs that use Kevlar, increasing the strength, or tenacity, to weight ratio would improve performance or reduce cost of all products that are based on this material. This thesis computationally and experimentally investigates the tenacity and stiffness of Kevlar yarns with varying twist ratios. The test boundary conditions were replicated with a geometrically accurate finite element model, resulting in a customized code that can reproduce tortuous filaments in a yarn was developed. The solid model geometry capturing filament tortuosity was implemented through a random walk method of axial geometry creation. A finite element analysis successfully recreated the yarn strength and stiffness dependency observed during the tests. The physics applied in the finite element model was reproduced in an analytical equation that was able to predict the failure strength and strain dependency of twist ratio. The analytical solution can be employed to optimize yarn design for high strength applications.

  16. Metallization of Kevlar fibers with gold.

    PubMed

    Little, Brian K; Li, Yunfeng; Cammarata, V; Broughton, R; Mills, G

    2011-06-01

    Electrochemical gold plating processes were examined for the metallization of Kevlar yarn. Conventional Sn(2+)/Pd(2+) surface activation coupled with electroless Ni deposition rendered the fibers conductive enough to serve as cathodes for electrochemical plating. The resulting coatings were quantified gravimetrically and characterized via adhesion tests together with XRD, SEM, TEM; the coatings effect on fiber strength was also probed. XRD data showed that metallic Pd formed during surface activation whereas amorphous phases and trace amounts of pure Ni metal were plated via the electroless process. Electrodeposition in a thiosulfate bath was the most efficient Au coating process as compared with the analogous electroless procedure, and with electroplating using a commercial cyanide method. Strongly adhering coatings resulted upon metallization with three consecutive electrodepositions, which produced conductive fibers able to sustain power outputs in the range of 1 W. On the other hand, metallization affected the tensile strength of the fiber and defects present in the metal deposits make questionable the effectiveness of the coatings as protective barriers. PMID:21574628

  17. The large deformation elastic response of woven Kevlar fabric

    SciTech Connect

    Warren, W.E.

    1991-01-01

    The large deformation elastic response of a plane woven Kevlar fabric is investigated analytically and experimentally. The analysis assumes the undeformed geometry to be a sequence of interlaced arcs of circles which reverse at each yarn midpoint, ad each yarn is modeled as an extensible elastical subject to certain compatibility conditions. Deflection-force relations for the fabric are determined in terms of the initial weave geometry and the elastic properties of the individual yarns. The theoretical results agree well with the results of experiments performed on a fabric woven from 400 denier Kevlar yarns under conditions of uniaxial loading in both warp and fill directions. 13 refs., 4 figs.

  18. The effect of configuration on strength, durability, and handle of Kevlar fabric-based materials

    NASA Technical Reports Server (NTRS)

    Reuter, L. L.; Munson, J. B.

    1977-01-01

    Five Kevlar based laminates and three Kevlar based coated materials were designed, hand made, and tested against comparative conventional Dacron based materials for strength, peel, tear, puncture, creases, and handle. Emphasis was placed on evaluating geometric orientation of constituents, use of elastomeric film in place of high modulus films, and the use of flying thread loom bias reinforcement of Kevlar yarns. Whereas, the performance of the Kevlar laminates was severely degraded by crease effects, significant gains in overall performance factors were shown for the coated Kevlar materials.

  19. Pulmonary response to inhaled Kevlar aramid synthetic fibers in rats.

    PubMed

    Lee, K P; Kelly, D P; Kennedy, G L

    1983-11-01

    Groups of male rats were exposed to specially prepared ultrafine Kevlar pulp fibers (du Pont's registered trademark for certain aramid fibers) at atmospheric concentrations of either 0.1, 0.5, 3.0, or 18 mg/m3 for 2 weeks. Rats were killed at 0 and 2 weeks and 3 and 6 months postexposure (PE) except the rats exposed to 18 mg/m3, which were killed 0, 4, and 14 days and 1, 3, and 6 months PE. Another group of male rats was exposed to 18 mg/m3 (respirable dust approximately 2.5 mg/m3) of commercial Kevlar fibers for 2 weeks and were killed at 0 and 2 weeks and 3 and 6 months PE. Inhaled ultrafine Kevlar fibers were mostly phagocytized by alveolar macrophages (dust cells) in the alveolar ducts and adjoining alveoli after exposure to either 0.1 or 0.5 micrograms/m3. Most dust cells had disappeared and lungs showed a normal appearance throughout 6 months PE. The pulmonary response almost satisfied the biological criteria for a nuisance dust. Rats exposed to 3 mg/m3 ultrafine Kevlar fibers revealed occasional patchy thickening of alveolar ducts with dust cells and inflammatory cells but with no collagen fibers deposited throughout 6 months PE. After exposure to 18 mg/m3 ultrafine Kevlar, the respiratory bronchioles, alveolar ducts, and adjoining alveoli showed granulomatous lesions with dust cells by 2 weeks PE. The granulomatous lesions converted to patchy fibrotic thickening with dust cells after 1 month PE. The fibrotic lesions were markedly reduced in cellularity, size, and numbers from 3 to 6 months PE but revealed networks of reticulum fibers with slight collagen fiber deposition. PMID:6636189

  20. [Research on structure of MC-nylon 6/aramid composites by spectroanalysis method].

    PubMed

    Wang, Can-Yao; Zheng, Yu-Ying

    2008-01-01

    The Kevlar fiber, treated with toluene-2,4-diisocyanate and caprolactam, was used to reinforce MC nylon 6. XPS showed the change in chemical components and spectra after fiber was treated. IR showed that the spectra of Kevlar fiber and MC-nylon 6 were incorporated purely when they were mixed, while the treated Kevlar fiber provided the activation in the ring-opening polymerization of caprolactam, and the amide groups of graft chains could form strong hydrogen bonds with matrix. These graft chains and hydrogen bonds would contribute to improving interfacial bonding between MC-nylon 6 and Kevlar fiber. XRD indicated that the induction of Kevlar fiber had no effect on the cryastalline style of MC-nylon 6 obviously, however, the crystals had better seasonal structure. The crystals of MC-nylon 6/Kevlar fiber composites were more perfect than that of MC-nylon 6/Kevlar untreated fiber composites with the same amount of Kevlar fiber. The increase of Kevlar fiber contributed to forming perfect a spherulite when the mass concentration of Kevlar fiber was less than 2%, however, the more the Kevlar fiber, the less the content of a spherulite when the mass concentration of Kevlar fiber was more than 2%. PMID:18422127

  1. A comparison of wire- and Kevlar-reinforced provisional restorations.

    PubMed

    Powell, D B; Nicholls, J I; Yuodelis, R A; Strygler, H

    1994-01-01

    Stainless steel wire 0.036 inch in diameter was compared with Kevlar 49 polyaramid fiber as a means of reinforcing a four-unit posterior provisional fixed restoration with 2 pontics. Three reinforcement patterns for wire and two for Kevlar 49 were evaluated and compared with the control, which was an unreinforced provisional restoration. A central tensile load was placed on the cemented provisional restoration and the variables were measured: (1) the initial stiffness; (2) the load at initial fracture; and (3) the unit toughness, or the energy stored in the beam at a point where the load had undergone a 1.0-mm deflection. Statistical analysis showed (1) the bent wire configuration had a significantly higher initial stiffness (P < or = .05), (2) there was no difference between designs for load at initial fracture, and (3) the bent wire had a significantly higher unit toughness value (P < or = .05). PMID:8179789

  2. Analysis methods for Kevlar shield response to rotor fragments

    NASA Technical Reports Server (NTRS)

    Gerstle, J. H.

    1977-01-01

    Several empirical and analytical approaches to rotor burst shield sizing are compared and principal differences in metal and fabric dynamic behavior are discussed. The application of transient structural response computer programs to predict Kevlar containment limits is described. For preliminary shield sizing, present analytical methods are useful if insufficient test data for empirical modeling are available. To provide other information useful for engineering design, analytical methods require further developments in material characterization, failure criteria, loads definition, and post-impact fragment trajectory prediction.

  3. Feasibility of Kevlar 49/PMR-15 polyimide for high temperature applications

    NASA Technical Reports Server (NTRS)

    Hanson, M. P.

    1980-01-01

    Kevlar 49 aramid organic fiber reinforced PMR-15 polyimide laminates were characterized to determine the applicability of the material to high temperature aerospace structures. Kevlar 49/3501-6 epoxy laminates were fabricated and characterized for comparison with the Kevlar 49/PMR-15 polyimide material. Flexural strengths and moduli and interlaminar shear strengths were determined from 75 to 600 F for the PMR-15 and from 75 to 450 F for the Kevlar 49/3501-6 epoxy material. The study also included the effects of hydrothermal and long-term elevated temperature exposures on the flexural strengths and moduli and the interlaminar shear strengths.

  4. Feasibility of Kevlar 49/PMR-15 Polyimide for High Temperature Applications

    NASA Technical Reports Server (NTRS)

    Hanson, M. P.

    1980-01-01

    Kevlar 49 aramid organic fiber reinforced PMR-15 polyimide laminates were characterized to determine the applicability of the material to high temperature aerospace structures. Kevlar 49/3501-6 epoxy laminates were fabricated and characterized for comparison with the Kevlar 49/PMR-15 polyimide material. Flexural strengths and moduli and interlaminar shear strengths were determined from 75 F to 600 F for the PMR-15 and from 75 F to 450 F for the Kevlar/3501-6 epoxy material. The effects of hydrothermal and long-term elevated temperature exposures on the flexural strengths and moduli and the interlaminar shear strengths were also studied.

  5. A Kinematic, Kevlar(registered) Suspension System for an ADR

    NASA Technical Reports Server (NTRS)

    Voellmer, George M.; Jackson, Michael L.; Shirron, Peter J.; Tuttle, James G.

    2003-01-01

    The High Resolution Airborne Wideband Camera (HAWC) and the Submillimeter And Far Infrared Experiment (SAFIRE) will use identical Adiabatic Demagnetization Refrigerators (ADR) to cool their bolometer detectors to 200mK and 100mK, respectively. In order to minimize thermal loads on the salt pill, a Kevlar@ suspension system is used to hold it in place. An innovative, kinematic suspension system is presented. The suspension system is unique in that it consists or two parts that can be assembled and tensioned offline, and later bolted onto the salt pill. The resulting assembly constrains each degree of freedom only once, yielding a kinematic, tensile structure.

  6. Intricacies of Using Kevlar and Thermal Knives in a Deployable Release System: Issues and Solutions

    NASA Technical Reports Server (NTRS)

    Stewart, Alphonso C.; Hair, Jason H.; Broduer, Steve (Technical Monitor)

    2002-01-01

    The utilization of Kevlar cord and thermal knives in a deployable release system produces a number of issues that must be addressed in the design of the system. This paper proposes design considerations that minimize the major issues, thermal knife failure, Kevlar cord relaxation, and the measurement of the cord tension. Design practices can minimize the potential for thermal knife laminate and element damage that result in failure of the knife. A process for in-situ inspection of the knife with resistance, rather than continuity, checks and 10x zoom optical imaging can detect damaged knives. Tests allow the characterization of the behavior of the particular Kevlar cord in use and the development of specific pre-stretching techniques and initial tension values needed to meet requirements. A new method can accurately measure the tension of the Kevlar cord using a guitar tuner, because more conventional methods do not apply to arimid cords such as Kevlar.

  7. Intricacies of Using Kevlar Cord and Thermal Knives in a Deployable Release System: Issues and Solutions

    NASA Technical Reports Server (NTRS)

    Stewart, Alphonso; Hair, Jason H.

    2002-01-01

    The utilization of Kevlar cord and thermal knives in a deployable release system produces a number of issues that must be addressed in the design of the system. This paper proposes design considerations that minimize the major issues, thermal knife failure, Kevlar cord relaxation, and the measurement of the cord tension. Design practices can minimize the potential for thermal knife laminate and element damage that result in failure of the knife. A process for in-situ inspection of the knife with resistance, rather than continuity, checks and 10x zoom optical imaging can detect damaged knives. Tests allow the characterization of the behavior of the particular Kevlar cord in use and the development of specific prestretching techniques and initial tension values needed to meet requirements. A new method can accurately measure the tension of the Kevlar cord using a guitar tuner, because more conventional methods do not apply to arimid cords such as Kevlar.

  8. Kinetics for the degradation of nylon and Kevlar parachute materials

    SciTech Connect

    Auerbach, I.

    1986-01-01

    The degradation of nylon 66 and Kevlar 29 yarns at elevated temperatures and over a broad range of humidities was studied and a rate relationship developed which models the degradation and permits computation of rate constants. The degradation rates are slow initially due to the presence of an inhibitor but increase rapidly as the inhibitor is depleted. The effect of relative humidity (RH) can be very large especially at values in the 100% range. An exponential relationship exists for nylon between the rate constant and RH. Kinetic parameters were evaluated and the rate constants at 25/sup 0/C calculated. These values showed that the tensile strength of nylon 66 will remain at a safe level over a 25-year period if the humidity is maintained at the 10% range or less. Kevlar 29 is more resistant and can tolerate humidity levels in the range of 90% or less. Degradation is governed by thermal-oxidative and moisture induced mechanisms. At the very high humidities the moisture induced degradation predominates. A relationship is developed which predicts the degradation rate over a very broad range of temperatures and humidities.

  9. Quality-assurance tests of five Y-12 Kevlar-49 spools used to fabricate strands and reliability specimens for stress-rupture tests

    SciTech Connect

    Caley, L.E.; Ambalal, P.K.; Carley, J.F.; Ford, T.S.; Moore, R.L.; Noecker, D.J.; Ross, M.E.; Sherry, R.J.; Yoshiyama, J.M.

    1984-05-07

    An important component of the composite reliability program is the assurance of quality of Kevlar 49, 380-denier yarn and epoxy-impregnated yarn. This yarn, which is used in the fabrication of W-82 components from Kevlar 49/epoxy composites, is also formed into test specimens for long-term, stress-rupture studies and reliability studies. The QA work covered in this report encompasses preparation of impregnated-yarn specimens, examination of the yarn itself and individual fibers therefrom, tensile testing of bare and impregnated yarns and heat-degraded yarns. The yarn samples were all drawn from spools of 380-denier Kevlar 49 shipped to LLNL from Y-12. The resin matrix is an amine-hardened epoxy with low viscosity and long pot life, intended for filament winding. The components are Dow epoxy resin (DER) 332 and Jeffamine T-403 triamine hardener. The stoichiometric combining ratio, which we used in our work, is 100 parts by weight resin to 44 parts hardener. Quality-assurance testing not only verifies that the yarns actually meet the manufacturer's specifications, but also provides data on the relationships between fiber characteristics and the lifetime reliability of fabricated items.

  10. Development of an alternating flat to tubular Kevlar parachute tape

    SciTech Connect

    Ericksen, R.H.; Koch, R.

    1989-01-01

    An alternating flat to tubular Kevlar tape was developed to replace braided suspension lines and woven tape radials on the new crew escape module parachute system for the F-111 aircraft. Weaves were developed which had high strength efficiency and low weight throughout the flat, tubular, and transition sections. A tubular section strength of 535 lbs at a weight of 0.044 oz/yd was achieved. This reduces suspension line weight by 8% compared with that of the most efficient braid which has a strength of 470 lbs and weighs 0.048 oz/yd. Length measuring procedures for production control and inspection were developed. Using these procedures it was possible to produce alternating weave fabric with less than 1% variation in length in the tubular sections. 3 refs., 4 figs., 3 tabs.

  11. An experimental study of the effects of water repellant treatment on the acoustic properties of Kevlar

    NASA Technical Reports Server (NTRS)

    Smith, C. D.; Parrott, T. L.

    1978-01-01

    The treatment consisted of immersing samples of Kevlar in a solution of distilled water and Zepel. The samples were then drained, dried in a circulating over, and cured. Flow resistance tests showed approximately one percent decrease in flow resistance of the samples. Also there was a density increase of about three percent. It was found that the treatment caused a change in the texture of the samples. There were significant changes in the acoustic properties of the treated Kevlar over the frequency range 0.5 to 3.5 kHz. In general it was found that the propagation constant and characteristic impedance increased with increasing frequency. The real and imaginary components of the propagation constant for the treated Kevlar exhibited a decrease of 8 to 12 percent relative to that for the untreated Kevlar at the higher frequencies. The magnitude of the reactance component of the characteristic impedance decreased by about 40 percent at the higher frequencies.

  12. Kevlar based nanofibrous particles as robust, effective and recyclable absorbents for water purification.

    PubMed

    Nie, Chuanxiong; Peng, Zihang; Yang, Ye; Cheng, Chong; Ma, Lang; Zhao, Changsheng

    2016-11-15

    Developing robust and recyclable absorbents for water purification is of great demand to control water pollution and to provide sustainable water resources. Herein, for the first time, we reported the fabrication of Kevlar nanofiber (KNF) based composite particles for water purification. Both the KNF and KNF-carbon nanotube composite particles can be produced in large-scale by automatic injection of casting solution into ethanol. The resulted nanofibrous particles showed high adsorption capacities towards various pollutants, including metal ions, phenylic compounds and various dyes. Meanwhile, the adsorption process towards dyes was found to fit well with the pseudo-second-order model, while the adsorption speed was controlled by intraparticle diffusion. Furthermore, the adsorption capacities of the nanofibrous particles could be easily recovered by washing with ethanol. In general, the KNF based particles integrate the advantages of easy production, robust and effective adsorption performances, as well as good recyclability, which can be used as robust absorbents to remove toxic molecules and forward the application of absorbents in water purification. PMID:27427892

  13. In-line Kevlar filters for microfiltration of transuranic-containing liquid streams.

    PubMed

    Gonzales, G J; Beddingfield, D H; Lieberman, J L; Curtis, J M; Ficklin, A C

    1992-06-01

    The Department of Energy Rocky Flats Plant has numerous ongoing efforts to minimize the generation of residue and waste and to improve safety and health. Spent polypropylene liquid filters held for plutonium recovery, known as "residue," or as transuranic mixed waste contribute to storage capacity problems and create radiation safety and health considerations. An in-line process-liquid filter made of Kevlar polymer fiber has been evaluated for its potential to: (1) minimize filter residue, (2) recover economically viable quantities of plutonium, (3) minimize liquid storage tank and process-stream radioactivity, and (4) reduce potential personnel radiation exposure associated with these sources. Kevlar filters were rated to less than or equal to 1 mu nominal filtration and are capable of reducing undissolved plutonium particles to more than 10 times below the economic discard limit, however produced high back-pressures and are not yet acid resistant. Kevlar filters performed independent of loaded particles serving as a sieve. Polypropylene filters removed molybdenum particles at efficiencies equal to Kevlar filters only after loading molybdenum during recirculation events. Kevlars' high-efficiency microfiltration of process-liquid streams for the removal of actinides has the potential to reduce personnel radiation exposure by a factor of 6 or greater, while simultaneously achieving a reduction in the generation of filter residue and waste by a factor of 7. Insoluble plutonium may be recoverable from Kevlar filters by incineration. PMID:1628993

  14. Investigation of woven composites as potential cryogenic tank materials

    NASA Astrophysics Data System (ADS)

    Islam, Md. S.; Melendez-Soto, E.; Castellanos, A. G.; Prabhakar, P.

    2015-12-01

    In this paper, carbon fiber and Kevlar® fiber woven composites were investigated as potential cryogenic tank materials for storing liquid fuel in spacecraft or rocket. Towards that end, both carbon and Kevlar® fiber composites were manufactured and tested with and without cryogenic exposure. The focus was on the investigation of the influence of initial cryogenic exposure on the degradation of the composite. Tensile, flexural and inter laminar shear strength (ILSS) tests were conducted, which indicate that Kevlar® and carbon textile composites are potential candidates for use under cryogenic exposure.

  15. Strain Measurement during Stress Rupture of Composite Over-Wrapped Pressure Vessel with Fiber Bragg Gratings Sensors

    NASA Technical Reports Server (NTRS)

    Banks, Curtis E.; Grant, Joseph; Russell, Sam; Arnett, Shawn

    2008-01-01

    Fiber optic Bragg gratings were used to measure strain fields during Stress Rupture (SSM) test of Kevlar Composite Over-Wrapped Pressure Vessels (COPV). The sensors were embedded under the over-wrapped attached to the liner released from the Kevlar and attached to the Kevlar released from the liner. Additional sensors (foil gages and fiber bragg gratings) were surface mounted on the COPY liner.

  16. Strain measurement during stress rupture of composite over-wrapped pressure vessel with fiber Bragg gratings sensors

    NASA Astrophysics Data System (ADS)

    Banks, Curtis E.; Grant, Joseph; Russell, Sam; Arnett, Shawn

    2008-03-01

    Fiber optic Bragg gratings were used to measure strain fields during Stress Rupture (SSM) test of Kevlar Composite Over-Wrapped Pressure Vessels (COPVs). The sensors were embedded under the over-wrapped attached to the liner released from the Kevlar and attached to the Kevlar released from the liner. Additional sensors (foil gages and fiber bragg gratings) were surface mounted on the COPV liner.

  17. Composite Materials

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Composites are lighter and stronger than metals. Aramid fibers like Kevlar and Nomex were developed by DuPont Corporation and can be combined in a honeycomb structure which can give an airplane a light, tough structure. Composites can be molded into many aerodynamic shapes eliminating rivets and fasteners. Langley Research Center has tested composites for both aerospace and non-aerospace applications. They are also used in boat hulls, military shelters, etc.

  18. Composites review

    NASA Technical Reports Server (NTRS)

    Hordonneau, A.

    1987-01-01

    The properties and applications of composite materials are reviewed. Glass, carbon, Kevlar, ceramic, whisker, and metal fibers are discussed along with polyester, epoxy, polyimide, Peek, carbon, ceramic, and metal matrices. The quantitative distribution of high technology fiber in various applications is given. The role of aerospace industry in the development and promotion of composite utilization is discussed. Consumption trends indicate a rapid development of the composite market.

  19. Why does Kevlar decompose, while Nomex does not, when treated with aqueous chlorine solutions?

    PubMed

    Akdag, Akin; Kocer, Hasan B; Worley, S D; Broughton, R M; Webb, T R; Bray, Travis H

    2007-05-24

    Kevlar and Nomex are high-performance polymers which have wide varieties of applications in daily life. Recently, they have been proposed to be biocidal materials when reacted with household bleach (sodium hypochlorite solution) because they contain amide moieties which can be chlorinated to generate biocidal N-halamine functional groups. Although Nomex can be chlorinated without any significant decomposition, Kevlar decomposes under the same chlorination conditions. In this study, two mimics for each of the polymers were synthesized to simulate the carboxylate and diaminophenylene components of the materials. It was found that the p-diaminophenylene component of the Kevlar mimic is oxidized to a quinone-type structure upon treatment with hypochlorous acid, which then decomposes. However, such a mechanism for the Nomex mimic is not possible. In this paper, based upon these observations, a plausible answer will be provided to the title question. PMID:17465537

  20. The Protective Effect of Kevlar ® Socks Against Hockey Skate Blade Injuries: A Biomechanical Study

    PubMed Central

    Nauth, Aaron; Aziz, Mina; Tsuji, Matthew; Whelan, Daniel B.; Theodoropoulos, John S.; Zdero, Rad

    2014-01-01

    Objectives: Several recent high profile injuries to elite players in the National Hockey League (NHL) secondary to skate blade lacerations have generated significant interest in these injuries and possible methods to protect against them. These injuries are typically due to direct contact of the skate blade of another player with posterior aspect of the calf resulting in a range of potential injuries to tendons or neurovascular structures. The Achilles tendon is most commonly involved. Kevlar® reinforced socks have recently become available for hockey players to wear and are cited as providing possible protection against such injuries. However, there has been no investigation of the possible protective effects of Kevlar® reinforced socks against skate blade injuries, and it is currently unknown what protective effects, if any, that these socks provide against these injuries. The proposed study sought to address this by conducting a biomechanical investigation of the protective effects of Kevlar® reinforced socks against Achilles tendon injuries in a simulated model of skate blade injury using human cadaver limbs. This novel investigation is the first to address the possible benefits to hockey players of wearing Kevlar® reinforced socks. Methods: Seven matched pairs of human cadaver lower limbs were fitted with a Kevlar ® reinforced sock comprised of 60% Kevlar®/20% Coolmax® polyester/18 % Nylon/12% Spandex (Bauer Elite Performance Skate Sock) on one limb and a standard synthetic sock comprised of 51% polyester/47% nylon/2% spandex (Bauer Premium Performance Skate Sock) on the contralateral limb as a control. Each limb was then mounted on a Materials Testing System (MTS) with the ankle dorsiflexed to 90° and the knee held in full extension using a custom designed jig. Specimens were then impacted with a hockey skate blade directed at the posterior calf, 12 cm above the heel, at an angle of 45° and a speed of 31m/s, to a penetration depth of 4.3 cm, to

  1. Local Strain Measurement of Kevlar Strand with Fiber Optic Bragg Grating

    NASA Technical Reports Server (NTRS)

    Banks, Curtis E.; Grant, Joseph; Russell, Sam; Arnett, Shawn

    2008-01-01

    1987 DuPont manufactured 4560 denier Kevlar/Epoxy Strands were instrumented with nine and three sensors each. Stress tests were performed at 30,45,60,70 and 80% of ultimate strength with dwell times of 10,000 seconds. FBG showed uneven stress levels which is contrary to conventional observation.

  2. Tensile testing of nylon and Kevlar parachute materials under Federal specified temperature and relative humidity conditions

    SciTech Connect

    Botner, W.T.

    1980-01-01

    A small 10-ft x 12-ft temperature and relative humidity controlled room for tensile testing of parachute materials is presented. Tensile tests of nylon and Kevlar parachute materials indicate there is a negligible change in break strength of test samples soaked in the controlled environment vs samples soaked in ambient conditions.

  3. Assessment of impact damage in Kevlar{reg_sign}-epoxy, filament-wound spherical test specimens by acoustic emission techniques

    SciTech Connect

    Whittaker, J.W.; Brosey, W.D.; Hamstad, M.A.

    1996-09-26

    The results of a study of the acoustic emission (AE) behavior of impact-damaged, spherical, composite test specimens subjected to thermal cycling and biaxial mechanical loading are presented. Seven Kevlar{reg_sign}-epoxy, filament-wound, spherical composite test specimens were subjected to different levels of impact damage. The seven specimens were a subset of a group of 77 specimens made with simulated fabrication-induced flaws. The specimens were subjected to two or three cycles of elevated temperature and then hydraulically pressurized to failure. The pressurization regime consisted of two cycles to different intermediate levels with a hold at each peak pressure level; a final pressurization to failure followed. The thermal and pressurization cycles were carefully designed to stimulate AE production under defined conditions. Both impacted and nonimpacted specimens produced thermo-AE (the term given to emission stimulated by thermal loading), but impacted specimens produced significantly more. Thermo-AE was produced primarily by damaged composite material. Damaged material produced emission as a function of both rising and falling temperature, but the effect was not repeatable. More seriously damaged specimens produced very large quantities of emission. Emission recorded during the static portion of the hydraulic loading cycles varied with load, time, and degree of damage. Static load AE behavior was quantified using a newly developed concept, the event-rate moment, and various correlations with residual strength were attempted. Correlations between residual strength, long-duration events, and even-rate moments were developed with varying degrees of success.

  4. Development of a low expansion, composite antenna subreflector with a frequency selective surface. [for Voyager spacecraft

    NASA Technical Reports Server (NTRS)

    Stonier, R. A.

    1977-01-01

    A Kevlar-49 epoxy, composite frequency-selective-surface subreflector was developed for the high gain antenna used on the Voyager spacecraft. The Kevlar-49 material was selected for this sandwich structure because a dielectric material was required, and the use of Kevlar-49 resulted in a composite sandwich with a low thermal coefficient of expansion and reduced weight over an equivalent fiberglass construction. A detailed description and the results of the development program are given and include the design requirements for the structure, the development testing of the materials that led to the final design configuration, and the processes used to fabricate this advanced composite spacecraft antenna component.

  5. A New and Innovative Use of the Thermal Knife and Kevlar Cord Components in a Restraint and Release System

    NASA Technical Reports Server (NTRS)

    Stewart, Alphonso; Brodeur, Stephen J. (Technical Monitor)

    2001-01-01

    A Kevlar cord and two thermal knives are key components in the Soar Array Restraint and Release System (SARRS) on the Microwave Anisotropy Probe (MAP) spacecraft at NASA's Goddard Space Flight Center. The SARRS uses a 25-foot (7.62 m) length Kevlar cord that encircles the spacecraft and secures the solar panels in stowed configuration for launch. Once in orbit, one of two redundantly configured thermal knives severs the Kevlar cord and permits the panels to deploy. The purpose of this paper is to present the details of the design, development test results, and the various innovations that were created during the development of this novel use of the thermal knife and Kevlar cord.

  6. [The research on the surfacial modification of organic high-performance Kevlar fiber].

    PubMed

    Zheng, Yu-ying; Fu, Ming-lian; Cai, Wei-long; Wang, Can-yao; Wang, Liang-en

    2004-04-01

    In the paper the authors tried to use chemical disposal to bring the activity mass onto the surface of Kevlar fiber with the purpose of surface graft modification. In the paper the authors used the FTIR spectra to discuss the graft of toluene-2, 4-diisocyanate onto Kevlar fiber. The authors studied and analysed the effect of hydrolytic time on the content of -O-H group of the production, and the effect of hydrolyzation and hexyl-lactam steadily disposing on the graft reaction. The result showed that the content of -O-H group increased after hydrolyzation, it's helpful for the graft reaction, and hexyl-lactam steadily disposing made the graf product more stable. Through the research the authors came to the conclusion that by bringing some activity masses onto the fiber surface the authors can improve the interface of fiber/resin effectively. PMID:15766145

  7. 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.

  8. High-energy-density composite flywheel

    NASA Astrophysics Data System (ADS)

    Satchwell, D. L.; Towgood, D. A.

    1980-02-01

    A flywheel was designed and fabricated to demonstrate a high energy density of 80 w-h/kg in the rotor. The rotor design consists of a multiring, subcircular rim made of S-glass/epoxy composite and Kevlar/epoxy composite materials and mounted on a spoked hub made of graphite/epoxy composite materials.

  9. Overview of NASA White Sands Test Facility Composite Overwrapped Pressure Vessel Testing

    NASA Technical Reports Server (NTRS)

    Greene, Nathanael; Saulsberry, Regor; Thesken, John; Phoenix, Leigh

    2006-01-01

    This viewgraph presentation examines the White Sands Test Facility testing of Composite overwrapped pressure vessel (COPV). A COPV is typically a metallic liner overwrapped with a fiber epoxy matrix. There is a weight advantage over the traditional all metal design. The presentation shows pictures of the facilities at White Sands, and then examines some of the testing performed. The tests include fluids compatibility, and Kevlar COPV. Data for the Kevlar tests are given, and an analysis is reviewed. There is also a comparison between Carbon COPVs and the Kevlar COPVs.

  10. Becoming "Highly Qualified"

    ERIC Educational Resources Information Center

    Quigley, Kimberly; Gomez, Cristina

    2006-01-01

    The Data Analysis for Teachers course helps teachers to learn instructional strategies, and make them "highly qualified" to teach mathematics for understanding. Going through the process of asking statistical questions, collecting appropriate data, analyzing the data, and interpreting the data was very exciting and students responded well when…

  11. Enhanced stab resistance of armor composites with functionalized silica nanoparticles

    NASA Astrophysics Data System (ADS)

    Mahfuz, Hassan; Clements, Floria; Rangari, Vijaya; Dhanak, Vinod; Beamson, Graham

    2009-03-01

    Traditionally shear thickening fluid (STF) reinforced with Kevlar has been used to develop flexible armor. At the core of the STF-Kevlar composites is a mixture of polyethylene glycol (PEG) and silica particles. This mixture is often known as STF and is consisted of approximately 45 wt % PEG and 55 wt % silica. During rheological tests, STF shows instantaneous spike in viscosity above a critical shear rate. Fabrication of STF-Kevlar composites requires preparation of STF, dilution with ethanol, and then impregnation with Kevlar. In the current approach, nanoscale silica particles were dispersed directly into a mixture of PEG and ethanol through a sonic cavitation process. Two types of silica nanoparticles were used in the investigation: 30 nm crystalline silica and 7 nm amorphous silica. The admixture was then reinforced with Kevlar fabric to produce flexible armor composites. In the next step, silica particles are functionalized with a silane coupling agent to enhance bonding between silica and PEG. The performance of the resulting armor composites improved significantly. As evidenced by National Institute of Justice spike tests, the energy required for zero-layer penetration (i.e., no penetration) jumped twofold: from 12 to 25 J cm2/g. The source of this improvement has been traced to the formation of siloxane (Si-O-Si) bonds between silica and PEG and superior coating of Kevlar filaments with particles. Fourier transform infrared, x-ray photoemission spectroscopy, and scanning electron microscopy studies were performed to examine chemical bonds, elemental composition, and particle dispersion responsible for such improvement. In summary, our experiments have demonstrated that functionalization of silica particles followed by direct dispersion into PEG resulted in superior Kevlar composites having much higher spike resistance.

  12. Hot Billet Surface Qualifier

    SciTech Connect

    Tzyy-Shuh Chang

    2007-04-30

    OG Technologies, Inc. (OGT), developed a prototype of a Hot Billet Surface Qualifier (“Qualifier”) based on OGT’s patented HotEye™ technology and other proprietary imaging and computing technologies. The Qualifier demonstrated its ability of imaging the cast billets in line with high definition pictures, pictures capable of supporting the detection of surface anomalies on the billets. The detection will add the ability to simplify the subsequent process and to correct the surface quality issues in a much more timely and efficient manner. This is challenging due to the continuous casting environment, in which corrosive water, temperature, vibration, humidity, EMI and other unbearable factors exist. Each installation has the potential of 249,000 MMBTU in energy savings per year. This represents a cost reduction, reduced emissions, reduced water usage and reduced mill scale.

  13. Ballistic Impact Response of Kevlar 49 and Zylon under Conditions Representing Jet Engine Fan Containment

    NASA Technical Reports Server (NTRS)

    Pereira, J. Michael; Revilock, Duane M.

    2007-01-01

    A ballistic impact test program was conducted to provide validation data for the development of numerical models of blade out events in fabric containment systems. The impact response of two different fiber materials - Kevlar 49 (E.I. DuPont Nemours and Company) and Zylon AS (Toyobo Co., Ltd.) was studied by firing metal projectiles into dry woven fabric specimens using a gas gun. The shape, mass, orientation and velocity of the projectile were varied and recorded. In most cases the tests were designed such that the projectile would perforate the specimen, allowing measurement of the energy absorbed by the fabric. The results for both Zylon and Kevlar presented here represent a useful set of data for the purposes of establishing and validating numerical models for predicting the response of fabrics under conditions simulating those of a jet engine blade release situation. In addition some useful empirical observations were made regarding the effects of projectile orientation and the relative performance of the different materials.

  14. Measurements on radiation shielding efficacy of Polyethylene and Kevlar in the ISS (Columbus)

    PubMed Central

    Di Fino, L.; Larosa, M.; Zaconte, V.; Casolino, M.; Picozza, P.; Narici, L.

    2014-01-01

    The study and optimization of material effectiveness as radiation shield is a mandatory step toward human space exploration. Passive radiation shielding is one of the most important element in the entire radiation countermeasures package. Crewmembers will never experience direct exposure to space radiation; they will be either inside some shelter (the spacecraft, a ‘base’) or in an EVA (Extra Vehicular Activity) suit. Understanding the radiation shielding features of materials is therefore an important step toward an optimization of shelters and suits construction in the quest for an integrated solution for radiation countermeasures. Materials are usually tested for their radiation shielding effectiveness first with Monte Carlo simulations, then on ground, using particle accelerators and a number of specific ions known to be abundant in space, and finally in space. Highly hydrogenated materials perform best as radiation shields. Polyethylene is right now seen as the material that merges a high level of hydrogenation, an easiness of handling and machining as well as an affordable cost, and it is often referred as a sort of ‘standard’ to which compare other materials' effectiveness. Kevlar has recently shown very interesting radiation shielding properties, and it is also known to have important characteristics toward debris shielding, and can be used, for example, in space suits. We have measured in the ISS the effectiveness of polyethylene and kevlar using three detectors of the ALTEA system [ 1– 3] from 8 June 2012 to 13 November 2012, in Express Rack 3 in Columbus. These active detectors are able to provide the radiation quality parameters in any orbital region; being identical, they are also suitable to be used in parallel (one for the unshielded baseline, two measuring radiation with two different amounts of the same material: 5 and 10 g/cm2). A strong similarity of the shielding behavior between polyethylene and kevlar is documented. We measured

  15. Bayes Analysis and Reliability Implications of Stress-Rupture Testing a Kevlar/Epoxy COPV using Temperature and Pressure Acceleration

    NASA Technical Reports Server (NTRS)

    Phoenix, S. Leigh; Kezirian, Michael T.; Murthy, Pappu L. N.

    2009-01-01

    Composite Overwrapped Pressure Vessel (COPVs) that have survived a long service time under pressure generally must be recertified before service is extended. Sometimes lifetime testing is performed on an actual COPV in service in an effort to validate the reliability model that is the basis for certifying the continued flight worthiness of its sisters. Currently, testing of such a Kevlar49(registered TradeMark)/epoxy COPV is nearing completion. The present paper focuses on a Bayesian statistical approach to analyze the possible failure time results of this test and to assess the implications in choosing between possible model parameter values that in the past have had significant uncertainty. The key uncertain parameters in this case are the actual fiber stress ratio at operating pressure, and the Weibull shape parameter for lifetime; the former has been uncertain due to ambiguities in interpreting the original and a duplicate burst test. The latter has been uncertain due to major differences between COPVs in the data base and the actual COPVs in service. Any information obtained that clarifies and eliminates uncertainty in these parameters will have a major effect on the predicted reliability of the service COPVs going forward. The key result is that the longer the vessel survives, the more likely the more optimistic stress ratio is correct. At the time of writing, the resulting effect on predicted future reliability is dramatic, increasing it by about one nine , that is, reducing the probability of failure by an order of magnitude. However, testing one vessel does not change the uncertainty on the Weibull shape parameter for lifetime since testing several would be necessary.

  16. Bayes Analysis and Reliability Implications of Stress-Rupture Testing a Kevlar/Epoxy COPV Using Temperature and Pressure Acceleration

    NASA Technical Reports Server (NTRS)

    Phoenix, S. Leigh; Kezirian, Michael T.; Murthy, Pappu L. N.

    2009-01-01

    Composite Overwrapped Pressure Vessels (COPVs) that have survived a long service time under pressure generally must be recertified before service is extended. Flight certification is dependent on the reliability analysis to quantify the risk of stress rupture failure in existing flight vessels. Full certification of this reliability model would require a statistically significant number of lifetime tests to be performed and is impractical given the cost and limited flight hardware for certification testing purposes. One approach to confirm the reliability model is to perform a stress rupture test on a flight COPV. Currently, testing of such a Kevlar49 (Dupont)/epoxy COPV is nearing completion. The present paper focuses on a Bayesian statistical approach to analyze the possible failure time results of this test and to assess the implications in choosing between possible model parameter values that in the past have had significant uncertainty. The key uncertain parameters in this case are the actual fiber stress ratio at operating pressure, and the Weibull shape parameter for lifetime; the former has been uncertain due to ambiguities in interpreting the original and a duplicate burst test. The latter has been uncertain due to major differences between COPVs in the database and the actual COPVs in service. Any information obtained that clarifies and eliminates uncertainty in these parameters will have a major effect on the predicted reliability of the service COPVs going forward. The key result is that the longer the vessel survives, the more likely the more optimistic stress ratio model is correct. At the time of writing, the resulting effect on predicted future reliability is dramatic, increasing it by about one "nine," that is, reducing the predicted probability of failure by an order of magnitude. However, testing one vessel does not change the uncertainty on the Weibull shape parameter for lifetime since testing several vessels would be necessary.

  17. Kevlar® as a Potential Accident Radiation Dosimeter for First Responders, Law Enforcement and Military Personnel.

    PubMed

    Romanyukha, Alexander; Trompier, François; Benevides, Luis A

    2016-08-01

    Today the armed forces and law enforcement personnel wear body armor, helmets, and flak jackets composed substantially of Kevlar® fiber to prevent bodily injury or death resulting from physical, ballistic, stab, and slash attacks. Therefore, there is a high probability that during a radiation accident or its aftermath, the Kevlar®-composed body armor will be irradiated. Preliminary study with samples of Kevlar® foundation fabric obtained from body armor used by the U.S. Marine Corps has shown that all samples evaluated demonstrated an EPR signal, and this signal increased with radiation dose. Based on these results, the authors predict that, with individual calibration, exposure at dose above 1 Gy can be reliably detected in Kevlar® samples obtained from body armor. As a result of these measurements, a post-event reconstruction of exposure dose can be obtained by taking various samples throughout the armor body and helmet worn by the same irradiated individual. The doses can be used to create a whole-body dose map that would be of vital importance in a case of a partial body or heterogeneous exposure. PMID:27356056

  18. Stress transfer of a Kevlar 49 fiber pullout test studied by micro-Raman spectroscopy.

    PubMed

    Lei, Zhenkun; Wang, Quan; Qiu, Wei

    2013-06-01

    The interfacial stress transfer behavior of a Kevlar 49 aramid fiber-epoxy matrix was studied with fiber pullout tests, the fibers of which were stretched by a homemade microloading device. Raman spectra on the embedded fiber were recorded by micro-Raman spectroscopy, under different strain levels. Then, the fiber axial stress was obtained by the relationship between the stress and Raman shift of the aramid fiber. Experimental results revealed that the fiber axial stress increased significantly with the load. The shear stress concentration occurred at the fiber entry to the epoxy resin. Thus, interfacial friction stages exist in the debonded fiber segment, and the interfacial friction shear stress is constant within one stage. The experimental results are consistent with the theoretical model predictions. PMID:23735244

  19. Eddy Current COPV Overwrap and Liner Thickness Measurement System and Data Analysis for 40-Inch Kevlar COPVs SN002 and SN027

    NASA Technical Reports Server (NTRS)

    Wincheski, Russell A.

    2008-01-01

    As part of the health assessment of flight spare 40in diameter Kevlar composite overwrapped pressure vessels (COPVs) SN002 and SN027 an eddy current characterization of the composite and liner thickness change during pressurization was requested under WSTF-TP-1085-07.A, "Space Shuttle Orbiter Main Propulsion System P/N MC282-0082-0101 S/N 002 and Orbital Maneuvering System P/N MC282-0082-001 S/N 027 COPV Health Assessment." The through the thickness strains have been determined to be an important parameter in the analysis of the reliability and likelihood of stress rupture failure. Eddy current techniques provide a means to measure these thicknesses changes based upon the change in impedance of an eddy current sensor mounted on the exterior of the vessel. Careful probe and technique design have resulted in the capability to independently measure the liner and overwrap thickness changes to better than +/- 0.0005 in. at each sensor location. Descriptions of the inspection system and test results are discussed.

  20. Experimental and Numerical Investigations on the Ballistic Performance of Polymer Matrix Composites Used in Armor Design

    NASA Astrophysics Data System (ADS)

    Colakoglu, M.; Soykasap, O.; Özek, T.

    2007-01-01

    Ballistic properties of two different polymer matrix composites used for military and non-military purposes are investigated in this study. Backside deformation and penetration speed are determined experimentally and numerically for Kevlar 29/Polivnyl Butyral and Polyethylene fiber composites because designing armors for only penetration is not enough for protection. After experimental ballistic tests, a model is constructed using finite element program, Abaqus. The backside deformation and penetration speed are determined numerically. It is found that the experimental and numeric results are in agreement and Polyethylene fiber composite has much better ballistic limit, the backside deformation, and penetration speed than those of Kevlar 29/Polivnyl Butyral composite if areal densities are considered.

  1. A novel Ag catalyzation process using swelling impregnation method for electroless Ni deposition on Kevlar® fiber

    NASA Astrophysics Data System (ADS)

    Pang, Hongwei; Bai, Ruicheng; Shao, Qinsi; Gao, Yufang; Li, Aijun; Tang, Zhiyong

    2015-12-01

    A novel Ag catalyzation process using swelling impregnation pretreatment method was developed for electroless nickel (EN) deposition on Kevlar fiber. Firstly, the fiber was immersed into an aqueous dimethylsulfoxide (DMSO) solution of silver nitrate to impart silver nitrate into the inner part of the fiber near the surface. Subsequently silver nitrate was reduced to metal silver nanoparticles on the fiber surface by treatment with aqueous solution of sodium borohydride. After electroless plating, a dense and homogeneous nickel coating was obtained on the fiber surface. The silver nanoparticles formed at the fiber surface functioned as a catalyst for electroless deposition as well as an anchor for the plated layer. The study also revealed that the incorporation of surfactant sodium dodecyl sulfate (SDS) in electroless nickel plating bath can enhance the adhesion strength of EN layer with the fiber surface and minimize the surface roughness of the EN coating. The Ni plated Kevlar fiber possessed excellent corrosion resistance and high tensile strength.

  2. Preliminary results of the effects of sewing, packing and parachute deployment on material strength. [Kevlar and nylon

    SciTech Connect

    Ericksen, R.H.; Pepper, W.B.; Whinery, L.D.

    1984-01-01

    Ribbon parachute fabrics were tested during development and production of a 24 ft parachute, and after 2.5 years ambient exposure at several storage sites. The effects of sewing, packing, and parachute deployment on material strength were obtained in the 1000 lb Kevlar ribbon after moisture exposure during packing, and when packed parachutes absorbed moisture or were thermal cycled. Individual yarn samples from the low strength ribbons exhibited little change in strength indicating that the material itself had not degraded. Factors leading to the change in ribbon strength are discussed. Considering all materials, there have been no indications to date of any uncontrollable changes in material strength that would limit the use of Kevlar in parachute applications.

  3. Composite containment systems for jet engine fan blades

    NASA Technical Reports Server (NTRS)

    Smith, G. T.

    1981-01-01

    The use of composites in fan blade containment systems is investigated and the associated structural benefits of the composite system design are identified. Two basic types of containment structures were investigated. The short finned concept was evaluated using Kevlar/epoxy laminates for fins which were mounted in a 6061 T-6 aluminum ring. The long fin concept was evaluated with Kevlar/epoxy, 6Al4V titanium, and 2024 T-3 aluminum fins. The unfinned configurations consisted of the base-line steel sheet, a circumferentially oriented aluminum honeycomb, and a Kevlar cloth filled ring. Results obtained show that a substantial reduction in the fan blade containment system weight is possible. Minimization of damage within the engine arising from impact interaction between blade debris and the engine structure is also achieved.

  4. [Research on the modification of Kevlar fiber by polypropylene glycol and cis-2-butene-1,4-diol].

    PubMed

    Zheng, Yu-ying; Wang, Can-yao; Fu, Ming-lian; Cai, Wei-long; Wang, Liang-en

    2005-03-01

    The mechanism of the modification of Kevlar fiber by polypropylene glycol(PPG) and cis-2-butene-1, 4-diol was studied in the paper, the authors learned the esterification of toluene-2, 4-diisocyanate (TDI) onto Kevlar fiber by infrared spectrum. In the mean time, the infrared spectrograms of the productions which steadily disposed by PPG and butendiol were analysed respectively, the result showed that the intensity of the bands was reinforced at about 1700-1720 cm(-1) after the samples were steadily disposed, that is to say, the group of --NCO has been stabilized into --NHCO group, the effect of steady disposal was obvious; but the disposal effect of butendiol was apparently better than PPG's at the same condition. Finally, the authors compared the influence of different mol rates between TDI and butendiol on the productions. Based onthe consequence, excessive butendiol would prevent the Kevlar fiber from farther reaction, therefore, the mol rate between TDI and butendiol should approach 1:1. PMID:16013317

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

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

  6. Pulmonary cellular effects in rats following aerosol exposures to ultrafine Kevlar aramid fibrils: evidence for biodegradability of inhaled fibrils.

    PubMed

    Warheit, D B; Kellar, K A; Hartsky, M A

    1992-10-01

    Previous chronic inhalation studies have shown that high concentrations of Kevlar fibrils produced fibrosis and cystic keratinizing tumors in rats following 2-year inhalation exposures. The current studies were undertaken to evaluate mechanisms and to assess the toxicity of inhaled Kevlar fibrils relative to other reference materials. Rats were exposed to ultrafine Kevlar fibers (fibrils) for 3 or 5 days at concentrations ranging from 600-1300 fibers/cc (gravimetric concentrations ranging from 2-13 mg/m3). A complete characterization of the fiber aerosol and dose was carried out. These measurements included gravimetric concentrations, mass median aerodynamic diameter, fiber number, and count median lengths and diameters of the aerosol. Following exposures, cells and fluids from groups of sham- and fiber-exposed animals were recovered by bronchoalveolar lavage (BAL). Alkaline phosphatase, lactate dehydrogenase (LDH), protein, and N-acetyl glucosaminidase (NAG) values were measured in BAL fluids at several time points postexposure. Alveolar macrophages were cultured and studied for morphology, chemotaxis, and phagocytosis by scanning electron microscopy. The lungs of additional exposed animals were processed for deposition, cell labeling, retained dose, and lung clearance studies, as well as fiber dimensions (from digested lung tissue), histopathology, and transmission electron microscopy. Five-day exposures to Kevlar fibrils elicited a transient granulocytic inflammatory response with concomitant increases in BAL fluid levels of alkaline phosphatase, NAG, LDH, and protein. Unlike the data from silica and asbestos exposures where inflammation persisted, biochemical parameters returned to control levels at time intervals between 1 week and 1 month postexposure. Macrophage function in Kevlar-exposed alveolar macrophages was not significantly different from sham controls at any time period. Cell labeling studies were carried out immediately after exposure, as well as 1

  7. The development of studying flexible pipe bend reinforced by Kevlar fibers

    NASA Astrophysics Data System (ADS)

    Shuai, Chang-Geng; He, Lin; Lu, Zhi-Qiang

    2003-12-01

    The flexible pipe bend can not only reduce the structural vibration and fluid noise in pipeline, but also realize the flexible connection of a horizontal line and a vertical line and compensate the displacement of three dimensions produced by the shock or vibration of pipeline in the special situations. Up to now, little attention has been paid to study the flexible pipe bend applied in the pipeline of medium or high pressure, because no appropriate framework materials can be used to reinforce it which must endure the burst pressure higher than 10 MPa. The investigation shows that it is possible to produce the flexible pipe bend of medium or high pressure if such fibers with high performance as Kevlar fibers are used to be its reinforced materials. However, its structural designing theory, manufacturing technology and measuring techniques aren’t yet perfect and systematic, which leads to the instability of the performance of products. Furthermore, few references about its research can be seen. Therefore, it is necessary to systematically and thoroughly develop the structural designing theory, manufacture technology and measuring techniques of flexible pipe bend.

  8. Evaluation of Thin Kevlar-Epoxy Fabric Panels Subjected to Shear Loading

    NASA Technical Reports Server (NTRS)

    Baker, Donald J.

    1996-01-01

    The results of an analytical and experimental investigation of 4-ply Kevlar-49-epoxy panels loaded by in-plane shear are presented. Approximately one-half of the panels are thin-core sandwich panels and the other panels are solid-laminate panels. Selected panels were impacted with an aluminum sphere at a velocity of either 150 or 220 ft/sec. The strength of panels impacted at 150 ft/sec was not reduced when compared to the strength of the undamaged panels, but the strength of panels impacted at 220 ft/sec was reduced by 27 to 40 percent. Results are presented for panels that were cyclically loaded from a load less than the buckling load to a load in the postbuckling load range. The thin-core sandwich panels had a lower fatigue life than the solid panels. The residual strength of the solid and sandwich panels cycled more than one million cycles exceeded the baseline undamaged panel strengths. The effect of hysteresis in the response of the sandwich panels is not significant. Results of a nonlinear finite element analysis conducted for each panel design are presented.

  9. Time-Dependent Behavior of High-Strength Kevlar and Vectran Webbing

    NASA Technical Reports Server (NTRS)

    Jones, Thomas C.; Doggett, William R.

    2014-01-01

    High-strength Kevlar and Vectran webbings are currently being used by both NASA and industry as the primary load-bearing structure in inflatable space habitation modules. The time-dependent behavior of high-strength webbing architectures is a vital area of research that is providing critical material data to guide a more robust design process for this class of structures. This paper details the results of a series of time-dependent tests on 1-inch wide webbing including an initial set of comparative tests between specimens that underwent realtime and accelerated creep at 65 and 70% of their ultimate tensile strength. Variability in the ultimate tensile strength of the webbings is investigated and compared with variability in the creep life response. Additional testing studied the effects of load and displacement rate, specimen length and the time-dependent effects of preconditioning the webbings. The creep test facilities, instrumentation and test procedures are also detailed. The accelerated creep tests display consistently longer times to failure than their real-time counterparts; however, several factors were identified that may contribute to the observed disparity. Test setup and instrumentation, grip type, loading scheme, thermal environment and accelerated test postprocessing along with material variability are among these factors. Their effects are discussed and future work is detailed for the exploration and elimination of some of these factors in order to achieve a higher fidelity comparison.

  10. Influence of strain rate on the quasi-static tensile strength of Kevlar 29 narrow fabrics

    SciTech Connect

    Ericksen, R.H.

    1981-01-01

    Increasing the strain rate from 3 x 10/sup -4/ min/sup -1/ to 1.4 min/sup -1/ resulted in a 20% increase in fabric strength. Similar changes in strength with strain rate were obtained for warp yarns removed from the fabrics. Static and sliding loop yarn tests, and tests in which yarn was interwoven through wires, were used to determine effect of abrasion, bending and lateral compression as a function of strain rate. Results eliminated yarn damage by abrasion and demonstrated that unwoven yarn strength, in presence of bending or lateral compression, was dependent on strain rate. Yarn and fiber pullout tests showed that increasing strain rate caused a transition from stick-slip to smooth curves. Results suggested a mechanism whereby strain-rate dependent frictional behavior of Kevlar influences woven fabric strength. It appears that friction restrains highly loaded fibers in a fabric from adjusting their position to relieve stress concentrations. Yarn tensile strength is influenced by strain rate when the fiber arrangement has been altered by weaving or when bending or lateral compressive forces are also present.

  11. Installing strain gauges on composite material

    NASA Astrophysics Data System (ADS)

    Shull, Larry

    The evolution of the strain gage is traced and problems associated with their use on composite materials are discussed. It is believed that the use of the computer in strain gage data systems has caused some of the attitude problems in measuring strains in composite materials. The performance of strain gages on filament-wound Kevlar pressure vessels is discussed as well as graphite composites during 1984-1986, surface preparation, gage location alignment.

  12. 7 CFR 1150.109 - Qualified program.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Agreements and Orders; Milk), DEPARTMENT OF AGRICULTURE DAIRY PROMOTION PROGRAM Dairy Promotion and Research Order Definitions § 1150.109 Qualified program. Qualified program means any dairy product...

  13. 7 CFR 1150.109 - Qualified program.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AGREEMENTS AND ORDERS; MILK), DEPARTMENT OF AGRICULTURE DAIRY PROMOTION PROGRAM Dairy Promotion and Research Order Definitions § 1150.109 Qualified program. Qualified program means any dairy product...

  14. 7 CFR 1150.109 - Qualified program.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AGREEMENTS AND ORDERS; MILK), DEPARTMENT OF AGRICULTURE DAIRY PROMOTION PROGRAM Dairy Promotion and Research Order Definitions § 1150.109 Qualified program. Qualified program means any dairy product...

  15. Tribological study of non-asbestos fiber reinforced phenolic composites for braking applications

    SciTech Connect

    Gopal, P.; Dharani, L.R.; Blum, F.D.

    1994-12-31

    A cashew modified phenolic resin was used as the binder to prepare several different nonasbestos fiber reinforced composite friction materials. Friction-wear tests were conducted at various loads, speeds and temperatures on a Chase friction testing machine. The fade and wear characteristics of glass and carbon fiber reinforced friction materials were studied. The wear rates of hybrid composites containing Kevlar{reg_sign} (registered trademark of E.I. duPont de Nemours) pulp were compared to those of control composites without Kevlar{reg_sign} pulp.

  16. Stress Rupture Life Reliability Measures for Composite Overwrapped Pressure Vessels

    NASA Technical Reports Server (NTRS)

    Murthy, Pappu L. N.; Thesken, John C.; Phoenix, S. Leigh; Grimes-Ledesma, Lorie

    2007-01-01

    Composite Overwrapped Pressure Vessels (COPVs) are often used for storing pressurant gases onboard spacecraft. Kevlar (DuPont), glass, carbon and other more recent fibers have all been used as overwraps. Due to the fact that overwraps are subjected to sustained loads for an extended period during a mission, stress rupture failure is a major concern. It is therefore important to ascertain the reliability of these vessels by analysis, since the testing of each flight design cannot be completed on a practical time scale. The present paper examines specifically a Weibull statistics based stress rupture model and considers the various uncertainties associated with the model parameters. The paper also examines several reliability estimate measures that would be of use for the purpose of recertification and for qualifying flight worthiness of these vessels. Specifically, deterministic values for a point estimate, mean estimate and 90/95 percent confidence estimates of the reliability are all examined for a typical flight quality vessel under constant stress. The mean and the 90/95 percent confidence estimates are computed using Monte-Carlo simulation techniques by assuming distribution statistics of model parameters based also on simulation and on the available data, especially the sample sizes represented in the data. The data for the stress rupture model are obtained from the Lawrence Livermore National Laboratories (LLNL) stress rupture testing program, carried out for the past 35 years. Deterministic as well as probabilistic sensitivities are examined.

  17. 42 CFR 495.204 - Incentive payments to qualifying MA organizations for qualifying MA-EPs and qualifying MA...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 5 2013-10-01 2013-10-01 false Incentive payments to qualifying MA organizations for qualifying MA-EPs and qualifying MA-affiliated eligible hospitals. 495.204 Section 495.204 Public... Requirements Specific to Medicare Advantage (MA) Organizations § 495.204 Incentive payments to qualifying...

  18. 42 CFR 495.204 - Incentive payments to qualifying MA organizations for qualifying MA-EPs and qualifying MA...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 5 2014-10-01 2014-10-01 false Incentive payments to qualifying MA organizations for qualifying MA-EPs and qualifying MA-affiliated eligible hospitals. 495.204 Section 495.204 Public... Requirements Specific to Medicare Advantage (MA) Organizations § 495.204 Incentive payments to qualifying...

  19. Lung response to ultrafine Kevlar aramid synthetic fibrils following 2-year inhalation exposure in rats.

    PubMed

    Lee, K P; Kelly, D P; O'Neal, F O; Stadler, J C; Kennedy, G L

    1988-07-01

    Four groups of 100 male and 100 female rats were exposed to ultrafine Kevlar fibrils at concentrations of 0, 2.5, 25, and 100 fibrils/cc for 6 hr/day, 5 days/week for 2 years. One group was exposed to 400 fibrils/cc for 1 year and allowed to recover for 1 year. At 2.5 fibrils/cc, the lungs had normal alveolar architecture with a few dust-laden macrophages (dust cell response) in the alveolar airspaces. At 25 fibrils/cc, the lungs showed a dust cell response, slight Type II pneumocyte hyperplasia, alveolar bronchiolarization, and a negligible amount of collagenized fibrosis in the alveolar duct region. At 100 fibrils/cc, the same pulmonary responses were seen as at 25 fibrils/cc. In addition, cystic keratinizing squamous cell carcinoma (CKSCC) was found in 4 female rats, but not in male rats. Female rats had more prominent foamy alveolar macrophages, cholesterol granulomas, and alveolar bronchiolarization. These pulmonary lesions were related to the development of CKSCC. The lung tumors were derived from metaplastic squamous cells in areas of alveolar bronchiolarization. At 400 fibrils/cc following 1 year of recovery, the lung dust content, average fiber length, and the pulmonary lesions were markedly reduced, but slight centriacinar emphysema and minimal collagenized fibrosis were found in the alveolar duct region. One male and 6 female rats developed CKSCC. The lung tumors were a unique type of experimentally induced tumors in the rats and have not been seen as spontaneous tumors in man or animals. Therefore, the relevance of this type of lung tumor to the human situation is minimal. PMID:3209007

  20. 75 FR 27934 - Qualified Nonpersonal Use Vehicles

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-19

    ... driver and all passengers of a qualified nonpersonal use vehicle. However, a working condition fringe... Internal Revenue Service 26 CFR Part 1 RIN 1545-BH65 Qualified Nonpersonal Use Vehicles AGENCY: Internal... regulations relating to qualified nonpersonal use vehicles as defined in section 274(i). Qualified...

  1. 20 CFR 302.3 - Qualifying conditions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 1 2012-04-01 2012-04-01 false Qualifying conditions. 302.3 Section 302.3 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD UNEMPLOYMENT INSURANCE ACT QUALIFIED EMPLOYEE § 302.3 Qualifying conditions. (a) Basic requirements. To qualify for benefits...

  2. 20 CFR 302.3 - Qualifying conditions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 1 2014-04-01 2012-04-01 true Qualifying conditions. 302.3 Section 302.3 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD UNEMPLOYMENT INSURANCE ACT QUALIFIED EMPLOYEE § 302.3 Qualifying conditions. (a) Basic requirements. To qualify for benefits...

  3. 20 CFR 302.3 - Qualifying conditions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 1 2013-04-01 2012-04-01 true Qualifying conditions. 302.3 Section 302.3... QUALIFIED EMPLOYEE § 302.3 Qualifying conditions. (a) Basic requirements. To qualify for benefits with... paragraph (a) of this section, service months deemed under § 210.3 of this chapter shall be disregarded....

  4. 20 CFR 302.3 - Qualifying conditions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 1 2010-04-01 2010-04-01 false Qualifying conditions. 302.3 Section 302.3 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD UNEMPLOYMENT INSURANCE ACT QUALIFIED EMPLOYEE § 302.3 Qualifying conditions. (a) Basic requirements. To qualify for benefits...

  5. 20 CFR 302.3 - Qualifying conditions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 1 2011-04-01 2011-04-01 false Qualifying conditions. 302.3 Section 302.3 Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD UNEMPLOYMENT INSURANCE ACT QUALIFIED EMPLOYEE § 302.3 Qualifying conditions. (a) Basic requirements. To qualify for benefits...

  6. NCLB: Highly Qualified Teachers - The Search for Highly Qualified Teachers

    ERIC Educational Resources Information Center

    Berry, Barnett; Hoke, Mandy; Hirsch, Eric

    2004-01-01

    At the same time that NCLB has given states a mandate to staff their classrooms with "highly qualified teachers," the federal government is pushing a dangerously narrow definition of the knowledge and skills that today's teachers need. Over the last decade, policy makers and business leaders have come to realize what parents have always known -…

  7. Energy-absorption capability and scalability of square cross section composite tube specimens

    NASA Technical Reports Server (NTRS)

    Farley, Gary L.

    1987-01-01

    Static crushing tests were conducted on graphite/epoxy and Kevlar/epoxy square cross section tubes to study the influence of specimen geometry on the energy-absorption capability and scalability of composite materials. The tube inside width-to-wall thickness (W/t) ratio was determined to significantly affect the energy-absorption capability of composite materials. As W/t ratio decreases, the energy-absorption capability increases nonlinearly. The energy-absorption capability of Kevlar epoxy tubes was found to be geometrically scalable, but the energy-absorption capability of graphite/epoxy tubes was not geometrically scalable.

  8. Energy-absorption capability and scalability of square cross section composite tube specimens

    NASA Technical Reports Server (NTRS)

    Farley, Gary L.

    1989-01-01

    Static crushing tests were conducted on graphite/epoxy and Kevlar/epoxy square cross section tubes to study the influence of specimen geometry on the energy-absorption capability and scalability of composite materials. The tube inside width-to-wall thickness (W/t) ratio was determined to significantly affect the energy-absorption capability of composite materials. As W/t ratio decreases, the energy-absorption capability increases nonlinearly. The energy-absorption capability of Kevlar epoxy tubes was found to be geometrically scalable, but the energy-absorption capability of graphite/epoxy tubes was not geometrically scalable.

  9. Plastic matrix composites with continuous fiber reinforcement

    SciTech Connect

    1991-09-19

    Most plastic resins are not suitable for structural applications. Although many resins are extremely tough, most lack strength, stiffness, and deform under load with time. By mixing strong, stiff, fibrous materials into the plastic matrix, a variety of structural composite materials can be formed. The properties of these composites can be tailored by fiber selection, orientation, and other factors to suit specific applications. The advantages and disadvantages of fiberglass, carbon-graphite, aramid (Kevlar 49), and boron fibers are summarized.

  10. Paralinguistic Qualifiers: Our Many Voices.

    ERIC Educational Resources Information Center

    Poyatos, Fernando

    1991-01-01

    A case is made for the increased study of paralinguistic voice qualifiers, which include variations in breathing, laryngeal, esophageal, pharyngeal, velopharyngeal, lingual, labial, mandibular, articulatory, articulatory tension, and objectual control. It is proposed that attention to these voice qualities has a variety of practical, literary,…

  11. Canada's Highly Qualified Manpower Resources.

    ERIC Educational Resources Information Center

    Atkinson, A. G.; And Others

    The purpose of this report is to assemble basic statistics on highly qualified manpower resources in Canada, especially focusing on scientists and engineers, for the development of policies and research in this field. The economic background contributing to the growth of the white-collar and professional labor force is discussed, and the roles of…

  12. Analysis of Potential for Titanium Liner Buckling after Proof in a Large Kevlar/Epoxy COPV

    NASA Technical Reports Server (NTRS)

    Phoenix, S. Leigh; Kezirian, Michael T.

    2009-01-01

    We analyze the potential for liner buckling in a 40-in Kevlar49/epoxy overwrapped spherical pressure vessel (COPV) due to long, local depressions or valleys in the titanium liner, which appeared after proof testing (autofrettage). We begin by presenting the geometric characteristics of approximately 20 mil (0.02 in.) deep depressions measured by laser profilometry in several vessels. While such depths were more typical, depths of more than 40 mils (0.02 in.) were seen near the equator in one particular vessel. Such depressions are largely the result of overlap of the edges of overwrap bands (with rectangular cross-section prepreg tows) from the first or second wrap patterns particularly where they start and end. We then discuss the physical mechanisms of formation of the depressions during the autofrettage process in terms of uneven void compaction in the overwrap around the tow overlap lines and the resulting 10-fold increase in through-thickness stiffness of the overwrap. We consider the effects of liner plastic yielding mechanisms in the liner on residual bending moments and interface pressures with the overwrap both at the peak proof pressure (approx.6500 psi) and when reducing the pressure to 0 psi. During depressurization the Bauschinger phenomenon becomes very important whereby extensive yielding in tension reduces the magnitude of the yield threshold in compression by 30 to 40%, compared to the virgin annealed state of the liner titanium. In the absence of a depression, the liner is elastically stable in compression even at liner overwrap interface pressures nominally 6 times the approx. 1000 psi interface pressure that exists at 0 psi. Using a model based on a plate-on-an-elastic-foundation, we develop an extensive analysis of the possible destabilizing effects of a frozen-in valley. The analysis treats the modifying effects of the residual bending moments and interface pressures remaining after the proof hold as well as the Bauschinger effect on the

  13. Tethers as Debris: Simulating Impacts of Kevlar Tethers on Shuttle Tiles

    NASA Technical Reports Server (NTRS)

    Evans, Steven W.

    2004-01-01

    In a previous paper I examined the effects of impacts of polymer tethers on aluminum plates using the SPHC hydrodynamic code. In this paper I apply tether models to a new target - models of Space Shuttle tiles developed during the STS 107 accident investigation. In this three-dimensional simulation, a short tether fragment strikes a single tile supported on an aluminum backing plate. A tile of the LI-900 material is modeled. Penetration and damage to the tile and the backwall are characterized for three normal impact velocities. The tether is modeled as a bundle of eight 1-mm strands, with the bundle having dimensions 2-mm x 4-mm x 20-cm. The bulk material properties used are those of Kevlar(TradeMark) 49, for which a Mie-Gruneisen multiphase equation of state (eos) is used. In addition, the strength model is applied in a linear sense, such that tensile loads along the strand length are supported, but there is no strength in the lateral directions. Tile models include the various layers making up the tile structure. The outermost layer is a relatively dense borosilicate glass, known as RCG, 0.5-mm thick. The RCG layer is present on the top and four sides of the tile. Below this coating is the bulk of the tile, 1.8- in thick, made of LI-900, a product consisting of rigidized fiberous silica with a density of 9 lWft3. Below the main insulating layer is a bottom layer of the same material that has been treated to increase its density by approximately 69% to improve its strength. This densified layer is bonded to a Strain Isolation Pad (SIP), modeled as a refractory felt fabric. The SIP is bonded to an aluminum 2024 wall 0.1-in thick. The tile and backwall materials use a Me-Gruneisen multiphase eos, with the exception of the SIP felt, which uses a fabric equation of state. Fabrics must be crushed to the full bulk material density before bulk material properties and a Mie-Gruneisen eos are applied. Tether fragment impact speeds of 3,7, and 10 km/s are simulated, with

  14. Effect of Mesoscale and Multiscale Modeling on the Performance of Kevlar Woven Fabric Subjected to Ballistic Impact: A Numerical Study

    NASA Astrophysics Data System (ADS)

    Jia, Xin; Huang, Zhengxiang; Zu, Xudong; Gu, Xiaohui; Xiao, Qiangqiang

    2013-12-01

    In this study, an optimal finite element model of Kevlar woven fabric that is more computational efficient compared with existing models was developed to simulate ballistic impact onto fabric. Kevlar woven fabric was modeled to yarn level architecture by using the hybrid elements analysis (HEA), which uses solid elements in modeling the yarns at the impact region and uses shell elements in modeling the yarns away from the impact region. Three HEA configurations were constructed, in which the solid element region was set as about one, two, and three times that of the projectile's diameter with impact velocities of 30 m/s (non-perforation case) and 200 m/s (perforation case) to determine the optimal ratio between the solid element region and the shell element region. To further reduce computational time and to maintain the necessary accuracy, three multiscale models were presented also. These multiscale models combine the local region with the yarn level architecture by using the HEA approach and the global region with homogenous level architecture. The effect of the varying ratios of the local and global area on the ballistic performance of fabric was discussed. The deformation and damage mechanisms of fabric were analyzed and compared among numerical models. Simulation results indicate that the multiscale model based on HEA accurately reproduces the baseline results and obviously decreases computational time.

  15. Tests of shielding effectiveness of Kevlar and Nextel onboard the International Space Station and the Foton-M3 capsule.

    PubMed

    Pugliese, M; Bengin, V; Casolino, M; Roca, V; Zanini, A; Durante, M

    2010-08-01

    Radiation assessment and protection in space is the first step in planning future missions to the Moon and Mars, where mission and number of space travelers will increase and the protection of the geomagnetic shielding against the cosmic radiation will be absent. In this framework, the shielding effectiveness of two flexible materials, Kevlar and Nextel, were tested, which are largely used in the construction of spacecrafts. Accelerator-based tests clearly demonstrated that Kevlar is an excellent shield for heavy ions, close to polyethylene, whereas Nextel shows poor shielding characteristics. Measurements on flight performed onboard of the International Space Station and of the Foton-M3 capsule have been carried out with special attention to the neutron component; shielded and unshielded detectors (thermoluminescence dosemeters, bubble detectors) were exposed to a real radiation environment to test the shielding properties of the materials under study. The results indicate no significant effects of shielding, suggesting that thin shields in low-Earth Orbit have little effect on absorbed dose. PMID:20364264

  16. 14 CFR 314.6 - Qualifying dislocation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Qualifying dislocation. 314.6 Section 314.6 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) PROCEDURAL REGULATIONS EMPLOYEE PROTECTION PROGRAM General § 314.6 Qualifying dislocation. A qualifying dislocation is...

  17. 7 CFR 4290.110 - Qualified management.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 15 2011-01-01 2011-01-01 false Qualified management. 4290.110 Section 4290.110... Qualifications for the RBIC Program Organizing A Rbic § 4290.110 Qualified management. An Applicant must show, to the satisfaction of the Secretary, that its current or proposed management team is qualified and...

  18. 7 CFR 4290.110 - Qualified management.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Qualified management. 4290.110 Section 4290.110... Qualifications for the RBIC Program Organizing A Rbic § 4290.110 Qualified management. An Applicant must show, to the satisfaction of the Secretary, that its current or proposed management team is qualified and...

  19. 7 CFR 4290.110 - Qualified management.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Qualified management. 4290.110 Section 4290.110... Qualifications for the RBIC Program Organizing A Rbic § 4290.110 Qualified management. An Applicant must show, to the satisfaction of the Secretary, that its current or proposed management team is qualified and...

  20. 7 CFR 4290.110 - Qualified management.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 15 2012-01-01 2012-01-01 false Qualified management. 4290.110 Section 4290.110... Qualifications for the RBIC Program Organizing A Rbic § 4290.110 Qualified management. Link to an amendment..., that its current or proposed management team is qualified and has the knowledge, experience,...

  1. Thermoplastic polymides and composites therefrom

    NASA Technical Reports Server (NTRS)

    Harris, Frank W. (Inventor)

    1994-01-01

    A new class polyimide and polyimide precursors based on diaryl oxyalkylene diamines, such as 1,3-bis[4-aminophenoxy]-2,2-dimethyl propane, a process for their preparation and their use as the continuous phase for the manufacture of composites and composite laminates reinforced by reinforcing agents such as carbon fibers, Kevlar.TM., and other similar high strength reinforcing agents. The polyimides and molecular composites obtained from the diamines according to the invention show thermoplastic properties, excellent flex fatigue and fracture resistance, and excellent thermal and oxidative stability.

  2. Quantitative radiographic analysis of fiber reinforced polymer composites.

    PubMed

    Baidya, K P; Ramakrishna, S; Rahman, M; Ritchie, A

    2001-01-01

    X-ray radiographic examination of the bone fracture healing process is a widely used method in the treatment and management of patients. Medical devices made of metallic alloys reportedly produce considerable artifacts that make the interpretation of radiographs difficult. Fiber reinforced polymer composite materials have been proposed to replace metallic alloys in certain medical devices because of their radiolucency, light weight, and tailorable mechanical properties. The primary objective of this paper is to provide a comparable radiographic analysis of different fiber reinforced polymer composites that are considered suitable for biomedical applications. Composite materials investigated consist of glass, aramid (Kevlar-29), and carbon reinforcement fibers, and epoxy and polyether-ether-ketone (PEEK) matrices. The total mass attenuation coefficient of each material was measured using clinical X-rays (50 kev). The carbon fiber reinforced composites were found to be more radiolucent than the glass and kevlar fiber reinforced composites. PMID:11261603

  3. Flight service evaluation of composite helicopter components

    NASA Technical Reports Server (NTRS)

    Rich, M. J.; Lowry, D. W.

    1982-01-01

    This first interim report presents the technical background for including environmental effects in the design of helicopter composite structures, and test results after approximately two year field exposure of components and panels. Composite structural components were removed from Sikorsky S-76 helicopters commercially operated in the Gulf Coast region of Louisiana. Fatigue tests were conducted for a graphite/epoxy tail rotor spar and static test for a graphite/epoxy and Kevlar/epoxy stabilizer. Graphite/epoxy and Kevlar/epoxy panels are being exposed to the outdoor environment in Stratford, Connecticut and West Palm Beach, Florida. For this reporting period the two year panels were returned, moisture measurements taken, and strength tests conducted. Results are compared with initial type certificate strengths for components and with initial laboratory coupon tests for the exposed panels. Comparisons are also presented with predicted and measured moisture contents.

  4. Effects Of Rapid Crushing On Composites

    NASA Technical Reports Server (NTRS)

    Farley, Gary L.

    1990-01-01

    Experimental study described in NASA technical memorandum performed to determine whether crash energy-absorption capabilities of graphite/epoxy and Kevlar/epoxy composite materials are functions of speed of crushing. Additional objective to develop understanding of mechanisms of crushing. Technology applied to enhancement of safety and crashworthiness of automobiles, design of energy-absorbing devices in machinery, and problems involving explosions and impacts.

  5. Chiral braided and woven composites: design, fabrication, and electromagnetic characterization

    NASA Astrophysics Data System (ADS)

    Wheeland, Sara; Bayatpur, Farhad; Amirkhizi, Alireza V.; Nemat-Nasser, Sia

    2011-04-01

    This work presents a new chiral composite composed of copper wires braided with Kevlar and nylon to form conductive coils integrated among structural fiber. To create a fabric, these braids were woven with plain Kevlar fiber. This yielded a composite with all coils possessing the same handedness, producing a chiral material. The electromagnetic response of this fabric was first simulated using a finite element full-wave simulation. For the electromagnetic measurement, the sample was placed between two lens-horn antennas connected to a Vector Network Analyzer. The frequency response of the sample was scanned between 5.5 and 8GHz. The measured scattering parameters were then compared to those of the simulated model. The measured parameters agreed well with the simulation results, showing a considerable chirality within the measured frequency band. The new composite combines the strength and durability of traditional composites with an electromagnetic design to create a multifunctional material.

  6. ISS qualified thermal carrier equipment

    NASA Astrophysics Data System (ADS)

    Deuser, Mark S.; Vellinger, John C.; Jennings, Wm. M.

    2000-01-01

    Biotechnology is undergoing a period of rapid and sustained growth, a trend which is expected to continue as the general population ages and as new medical treatments and products are conceived. As pharmaceutical and biomedical companies continue to search for improved methods of production and, for answers to basic research questions, they will seek out new avenues of research. Space processing on the International Space Station (ISS) offers such an opportunity! Space is rapidly becoming an industrial laboratory for biotechnology research and processing. Space bioprocessing offers exciting possibilities for developing new pharmaceuticals and medical treatments, which can be used to benefit mankind on Earth. It also represents a new economic frontier for the private sector. For over eight years, the thermal carrier development team at SHOT has been working with government and commercial sector scientists who are conducting microgravity experiments that require thermal control. SHOT realized several years ago that the hardware currently being used for microgravity thermal control was becoming obsolete. It is likely that the government, academic, and industrial bioscience community members could utilize SHOT's hardware as a replacement to their current microgravity thermal carrier equipment. Moreover, SHOT is aware of several international scientists interested in utilizing our space qualified thermal carrier. SHOT's economic financing concept could be extremely beneficial to the international participant, while providing a source of geographic return for their particular region. Beginning in 2000, flight qualified thermal carriers are expected to be available to both the private and government sectors. .

  7. Fracto-emission from graphite/epoxy composites

    NASA Technical Reports Server (NTRS)

    Dickinson, J. T.

    1983-01-01

    Fracto-emission (FE) is the emission of particles and photons during and following crack propagation. Electrons (EE), positive ions (PIE), and excited and ground state neutrals (NE) were observed. Results of a number of experiments involving principally graphite/epoxy composites and Kevlar single fibers are presented. The physical processes responsible for EE and PIE are discussed as well as FE from fiber- and particulate-reinforced composites.

  8. Absorption Of Crushing Energy In Square Composite Tubes

    NASA Technical Reports Server (NTRS)

    Farley, Gary L.

    1992-01-01

    Report describes investigation of crash-energy-absorbing capabilities of square-cross-section tubes of two matrix/fiber composite materials. Both graphite/epoxy and Kevlar/epoxy tubes crushed in progressive and stable manner. Ratio between width of cross section and thickness of wall determined to affect energy-absorption significantly. As ratio decreases, energy-absorption capability increases non-linearly. Useful in building energy-absorbing composite structures.

  9. A Logic for Qualified Syllogisms

    NASA Astrophysics Data System (ADS)

    Schwartz, Daniel G.

    In various works, L.A. Zadeh has introduced fuzzy quantifiers, fuzzy usuality modifiers, and fuzzy likelihood modifiers. This paper provides these notions with a unified semantics and uses this to define a formal logic capable of expressing and validating arguments such as 'Most birds can fly; Tweety is a bird; therefore, it is likely that Tweety can fly'. In effect, these are classical Aristotelean syllogisms that have been "qualified" through the use of fuzzy quantifiers. It is briefly outlined how these, together with some likelihood combination rules, can be used to address some well-known problems in the theory of nonmonotonic reasoning. The work is aimed at future applications in expert systems and robotics, including both hardware and software agents.

  10. Use of Raman Spectroscopy and Delta Volume Growth from Void Collapse to Assess Overwrap Stress Gradients Compromising the Reliability of Large Kevlar/Epoxy COPVs

    NASA Technical Reports Server (NTRS)

    Kezirian, Michael T.; Phoenix, S. Leigh; Eldridge, Jeffrey I.

    2009-01-01

    Composite Overwrapped Pressure Vessels (COPVs) are frequently used for storing pressurized gases aboard spacecraft and aircraft when weight saving is desirable compared to all-metal versions. Failure mechanisms in fibrous COPVs and variability in lifetime can be very different from their metallic counterparts; in the former, catastrophic stress-rupture can occur with virtually no warning, whereas in latter, a leak before burst design philosophy can be implemented. Qualification and certification typically requires only one burst test on a production sample (possibly after several pressure cycles) and the vessel need only meet a design burst strength (the maximum operating pressure divided by a knockdown factor). Typically there is no requirement to assess variability in burst strength or lifetime, much less determine production and materials processing parameters important to control of such variability. Characterizing such variability and its source is crucial to models for calculating required reliability over a given lifetime (e.g. R = 0.9999 for 15 years). In this paper we present a case study of how lack of control of certain process parameters in COPV manufacturing can result in variations among vessels and between production runs that can greatly increase uncertainty and reduce reliability. The vessels considered are 40-inch ( NASA Glenn Research center, Cleveland, OH, 44135 29,500 in3 ) spherical COPVs with a 0.74 in. thick Kevlar49/epoxy overwrap and with a titanium liner of which 34 were originally produced. Two burst tests were eventually performed that unexpectedly differed by almost 5%, and were 10% lower than anticipated from burst tests on 26-inch sister vessels similar in every detail. A major observation from measurements made during proof testing (autofrettage) of the 40-inch vessels was that permanent volume growth from liner yielding varied by a factor of more than two (150 in3 to 360 in3 ), which suggests large differences in the residual

  11. Characterization of Kevlar 49 fibers by electron paramagnetic resonance. Final report, 20 May 1981-20 June 1982. [Radicals induced by ultraviolet or fracture

    SciTech Connect

    Brown, I.M.; Sandreczki, T.C.

    1982-06-20

    EPR was used to investigate the free radicals created in Kevlar 49 fibers by stress-induced and photo-induced macromolecular chain scissions. Mn/sup +2/ ions were identified from the EPR spectrum of frozen solutions of concentrated sulfuric acid containing Kevlar 49. Other ions present are Cu/sup +2/, and possibly Fe/sup +3/, Cr/sup +3/, and Ti/sup +3/. EPR lineshape anisotropy indicates that some of the metal ions and first coordinate spheres are oriented. The concentration of stress-induced radicals (2 x 10/sup 10/ per filament) suggest that chain scission occurs in more weak planes than are estimated to exist in the fracture surfaces of the fiber core. These radicals are unstable in air and have some aromatic character. Several different types of radicals were obtained following uv irradiations of the Kevlar 49 fibers in vacuum (photodegradative radicals) and in air (photo-oxidative radicals). The photodegradative radicals are identified with primary radicals involved in the photo-Fries rearrangement reaction, secondary radicals formed as a result of a hydrogen atom abstraction by the primary radical, and/or ketyl radicals produced as a result of uv irradiation of the photo-Fries rearrangement product. The photo-oxidative radicals are identified with the uv irradiation products of a peroxide intermediate. Lineshape anisotropy indicates that both radical types are oriented. 31 figures.

  12. Documenting Characteristics of Highly Qualified Teachers

    ERIC Educational Resources Information Center

    Strain, Lucille B.

    2007-01-01

    Primarily because it is an aspect of the No Child Left Behind Act (NCLB), the concept of "highly qualified teacher" has become more important and more widely implemented throughout the schools of the United States. NCLB requires teachers in all pertinent schools to be highly qualified. Before NCLB, the concept was associated mainly with…

  13. Alaska High School Graduation Qualifying Examination Booklet.

    ERIC Educational Resources Information Center

    Alaska State Dept. of Education, Juneau.

    This booklet is an explanation of what the Alaska High School Graduation Qualifying Examination means to Alaskans and how it fits into a larger school accountability reform initiative. The high school class of 2002 is the first group of students who will need to pass the High School Graduation Qualifying Examination to receive a high school…

  14. 46 CFR 391.5 - Qualified withdrawals.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 8 2011-10-01 2011-10-01 false Qualified withdrawals. 391.5 Section 391.5 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION REGULATIONS UNDER PUBLIC LAW 91-469 FEDERAL INCOME TAX ASPECTS OF THE CAPITAL CONSTRUCTION FUND § 391.5 Qualified withdrawals. (a) In general. (1)...

  15. 46 CFR 391.5 - Qualified withdrawals.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 8 2013-10-01 2013-10-01 false Qualified withdrawals. 391.5 Section 391.5 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION REGULATIONS UNDER PUBLIC LAW 91-469 FEDERAL INCOME TAX ASPECTS OF THE CAPITAL CONSTRUCTION FUND § 391.5 Qualified withdrawals. (a) In general. (1)...

  16. 46 CFR 391.5 - Qualified withdrawals.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 8 2014-10-01 2014-10-01 false Qualified withdrawals. 391.5 Section 391.5 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION REGULATIONS UNDER PUBLIC LAW 91-469 FEDERAL INCOME TAX ASPECTS OF THE CAPITAL CONSTRUCTION FUND § 391.5 Qualified withdrawals. (a) In general. (1)...

  17. 46 CFR 391.5 - Qualified withdrawals.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Qualified withdrawals. 391.5 Section 391.5 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION REGULATIONS UNDER PUBLIC LAW 91-469 FEDERAL INCOME TAX ASPECTS OF THE CAPITAL CONSTRUCTION FUND § 391.5 Qualified withdrawals. (a) In general. (1)...

  18. 76 FR 60757 - Executive Branch Qualified Trusts

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-30

    ... qualified trusts provisions for the executive branch in subparts D and E of 5 CFR part 2634 (see 57 FR 11800.... 12674, 54 FR 15159, 3 CFR, 1989 Comp., p. 215, as modified by E.O. 12731, 55 FR 42547, 3 CFR, 1990 Comp... the use of a qualified blind trust is the lack of knowledge, or actual ``blindness,'' by an...

  19. 7 CFR 802.1 - Qualified laboratories.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Qualified laboratories. 802.1 Section 802.1... REQUIREMENTS FOR GRAIN WEIGHING EQUIPMENT AND RELATED GRAIN HANDLING SYSTEMS § 802.1 Qualified laboratories. (a) Metrology laboratories. (1) Any State metrology laboratory currently approved by the NBS...

  20. 30 CFR 795.10 - Qualified laboratories.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Qualified laboratories. 795.10 Section 795.10... laboratories. (a) Basic qualifications. To be designated a qualified laboratory, a firm shall demonstrate that... necessary field samples and making hydrologic field measurements and analytical laboratory determinations...

  1. 13 CFR 108.110 - Qualified management.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 13 Business Credit and Assistance 1 2011-01-01 2011-01-01 false Qualified management. 108.110... management. An Applicant must show, to the satisfaction of SBA, that its current or proposed management team is qualified and has the knowledge, experience, and capability in Community Development Finance...

  2. 7 CFR 802.1 - Qualified laboratories.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 7 2013-01-01 2013-01-01 false Qualified laboratories. 802.1 Section 802.1... REQUIREMENTS FOR GRAIN WEIGHING EQUIPMENT AND RELATED GRAIN HANDLING SYSTEMS § 802.1 Qualified laboratories. (a) Metrology laboratories. (1) Any State metrology laboratory currently approved by the NBS...

  3. 30 CFR 795.10 - Qualified laboratories.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Qualified laboratories. 795.10 Section 795.10... laboratories. (a) Basic qualifications. To be designated a qualified laboratory, a firm shall demonstrate that... necessary field samples and making hydrologic field measurements and analytical laboratory determinations...

  4. 30 CFR 795.10 - Qualified laboratories.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Qualified laboratories. 795.10 Section 795.10... laboratories. (a) Basic qualifications. To be designated a qualified laboratory, a firm shall demonstrate that... necessary field samples and making hydrologic field measurements and analytical laboratory determinations...

  5. 30 CFR 795.10 - Qualified laboratories.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Qualified laboratories. 795.10 Section 795.10... laboratories. (a) Basic qualifications. To be designated a qualified laboratory, a firm shall demonstrate that... necessary field samples and making hydrologic field measurements and analytical laboratory determinations...

  6. 7 CFR 802.1 - Qualified laboratories.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 7 2012-01-01 2012-01-01 false Qualified laboratories. 802.1 Section 802.1... REQUIREMENTS FOR GRAIN WEIGHING EQUIPMENT AND RELATED GRAIN HANDLING SYSTEMS § 802.1 Qualified laboratories. (a) Metrology laboratories. (1) Any State metrology laboratory currently approved by the NBS...

  7. 46 CFR 390.9 - Qualified withdrawals.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ..., construction or reconstruction its fair market value. The party must obtain the prior written permission of the... CONSTRUCTION FUND § 390.9 Qualified withdrawals. (a) In general—(1) Defined. In accordance with 46 U.S.C. 53509...: (i) The acquisition, construction or reconstruction of a qualified agreement vessel; (ii)...

  8. 46 CFR 390.9 - Qualified withdrawals.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., construction or reconstruction its fair market value. The party must obtain the prior written permission of the... CONSTRUCTION FUND § 390.9 Qualified withdrawals. (a) In general—(1) Defined. In accordance with 46 U.S.C. 53509...: (i) The acquisition, construction or reconstruction of a qualified agreement vessel; (ii)...

  9. 48 CFR 14.210 - Qualified products.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Qualified products. 14.210 Section 14.210 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES SEALED BIDDING Solicitation of Bids 14.210 Qualified products. See subpart 9.2....

  10. Material Issues in Space Shuttle Composite Overwrapped Pressure Vessels

    NASA Technical Reports Server (NTRS)

    Sutter, James K.; Jensen, Brian J.; Gates, Thomas S.; Morgan, Roger J.; Thesken, John C.; Phoenix, S. Leigh

    2006-01-01

    Composite Overwrapped Pressure Vessels (COPV) store gases used in four subsystems for NASA's Space Shuttle Fleet. While there are 24 COPV on each Orbiter ranging in size from 19-40", stress rupture failure of a pressurized Orbiter COPV on the ground or in flight is a catastrophic hazard and would likely lead to significant damage/loss of vehicle and/or life and is categorized as a Crit 1 failure. These vessels were manufactured during the late 1970's and into the early 1980's using Titanium liners, Kevlar 49 fiber, epoxy matrix resin, and polyurethane coating. The COPVs are pressurized periodically to 3-5ksi and therefore experience significant strain in the composite overwrap. Similar composite vessels were developed in a variety of DOE Programs (primarily at Lawrence Livermore National Laboratories or LLNL), as well as for NASA Space Shuttle Fleet Leader COPV program. The NASA Engineering Safety Center (NESC) formed an Independent Technical Assessment (ITA) team whose primary focus was to investigate whether or not enough composite life remained in the Shuttle COPV in order to provide a strategic rationale for continued COPV use aboard the Space Shuttle Fleet with the existing 25-year-old vessels. Several material science issues were examined and will be discussed in this presentation including morphological changes to Kevlar 49 fiber under stress, manufacturing changes in Kevlar 49 and their effect on morphology and tensile strength, epoxy resin strain, composite creep, degradation of polyurethane coatings, and Titanium yield characteristics.

  11. 40-in. OMS Kevlar(Registered Trademark) COPV S/N 007 Stress Rupture Test NDE

    NASA Technical Reports Server (NTRS)

    Saulsberry, Regor; Greene, Nate; Forth, Scott; Leifeste, Mark; Gallus, Tim; Yoder, Tommy; Keddy, Chris; Mandaras, Eric; Wincheski, Buzz; Williams, Philip; Russell, Richard; Eldridge, Jeff

    2010-01-01

    The presentation examines pretest nondestructive evaluation (NDE), including external/internal visual inspection, raman spectroscopy, laser shearography, and laser profilometry; real-time NDE including eddy current, acoustic emission (AE), and real-time portable raman spectroscopy; and AE application to carbon/epoxy composite overwrapped pressure vessels.

  12. Composite Overwrapped Pressure Vessel (COPV) Stress Rupture Testing

    NASA Technical Reports Server (NTRS)

    Greene, Nathanael J.; Saulsberry, Regor L.; Leifeste, Mark R.; Yoder, Tommy B.; Keddy, Chris P.; Forth, Scott C.; Russell, Rick W.

    2010-01-01

    This paper reports stress rupture testing of Kevlar(TradeMark) composite overwrapped pressure vessels (COPVs) at NASA White Sands Test Facility. This 6-year test program was part of the larger effort to predict and extend the lifetime of flight vessels. Tests were performed to characterize control parameters for stress rupture testing, and vessel life was predicted by statistical modeling. One highly instrumented 102-cm (40-in.) diameter Kevlar(TradeMark) COPV was tested to failure (burst) as a single-point model verification. Significant data were generated that will enhance development of improved NDE methods and predictive modeling techniques, and thus better address stress rupture and other composite durability concerns that affect pressure vessel safety, reliability and mission assurance.

  13. Composite Overwrapped Pressure Vessel(COPV) Stress Rupture Testing

    NASA Astrophysics Data System (ADS)

    Greene, Nathanael J.; Saulsberry, Regor L.; Leifeste, Mark, R.; Yoder, Tommy B.; Keddy, Chris P.; Forth, Scott C.; Russell, Rick W.

    2010-09-01

    This paper reports stress rupture testing of Kevlar® composite overwrapped pressure vessels(COPVs) at NASA White Sands Test Facility. This 6-year test program was part of the larger effort to predict and extend the lifetime of flight vessels. Tests were performed to characterize control parameters for stress rupture testing, and vessel life was predicted by statistical modeling. One highly instrumented 102-cm(40-in.) diameter Kevlar® COPV was tested to failure(burst) as a single-point model verification. Significant data were generated that will enhance development of improved NDE methods and predictive modeling techniques, and thus better address stress rupture and other composite durability concerns that affect pressure vessel safety, reliability and mission assurance.

  14. Compression failure mechanisms of composite structures

    NASA Technical Reports Server (NTRS)

    Hahn, H. T.; Sohi, M.; Moon, S.

    1986-01-01

    An experimental and analytical study was conducted to delineate the compression failure mechanisms of composite structures. The present report summarizes further results on kink band formation in unidirectional composites. In order to assess the compressive strengths and failure modes of fibers them selves, a fiber bundle was embedded in epoxy casting and tested in compression. A total of six different fibers were used together with two resins of different stiffnesses. The failure of highly anisotropic fibers such as Kevlar 49 and P-75 graphite was due to kinking of fibrils. However, the remaining fibers--T300 and T700 graphite, E-glass, and alumina--failed by localized microbuckling. Compressive strengths of the latter group of fibers were not fully utilized in their respective composite. In addition, acoustic emission monitoring revealed that fiber-matrix debonding did not occur gradually but suddenly at final failure. The kink band formation in unidirectional composites under compression was studied analytically and through microscopy. The material combinations selected include seven graphite/epoxy composites, two graphite/thermoplastic resin composites, one Kevlar 49/epoxy composite and one S-glass/epoxy composite.

  15. Prediction of the energy-absorption capability of composite tubes

    NASA Technical Reports Server (NTRS)

    Farley, Gary L.; Jones, Robert M.

    1992-01-01

    A method of predicting the crack-related energy-absorption capability of composite tubes is presented. The method is based upon a phenomenological model of the crushing process exhibited by continuous-fiber-reinforced tubes. A finite element method is used to model the crushing process. The analysis is compared with experiments on Kevlar-epoxy and graphite-epoxy tubes. Reasonable agreement is obtained between the analysis and experiment.

  16. Rapid detection and quantification of impact damage in composite structures

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N.; Farley, Gary; Smith, Barry T.

    1991-01-01

    NDE results from thermographic and volumetric ultrasonic techniques are presented to illustrate the multidisciplinary NDE approach to impact-damage detection in such composite structures as are increasingly prevalent in helicopters. Attention is given to both flat-panel and 'y-stiffened' panel specimens; these were fabricated either with kevlar or carbon fiber through-the-thickness reinforcements. While thermal inspection identifies impact damage, volumetric imaging quantifies the impact-generated delaminations through the volume of the structure.

  17. Flight Qualified Micro Sun Sensor

    NASA Technical Reports Server (NTRS)

    Liebe, Carl Christian; Mobasser, Sohrab; Wrigley, Chris; Schroeder, Jeffrey; Bae, Youngsam; Naegle, James; Katanyoutanant, Sunant; Jerebets, Sergei; Schatzel, Donald; Lee, Choonsup

    2007-01-01

    A prototype small, lightweight micro Sun sensor (MSS) has been flight qualified as part of the attitude-determination system of a spacecraft or for Mars surface operations. The MSS has previously been reported at a very early stage of development in NASA Tech Briefs, Vol. 28, No. 1 (January 2004). An MSS is essentially a miniature multiple-pinhole electronic camera combined with digital processing electronics that functions analogously to a sundial. A micromachined mask containing a number of microscopic pinholes is mounted in front of an active-pixel sensor (APS). Electronic circuits for controlling the operation of the APS, readout from the pixel photodetectors, and analog-to-digital conversion are all integrated onto the same chip along with the APS. The digital processing includes computation of the centroids of the pinhole Sun images on the APS. The spacecraft computer has the task of converting the Sun centroids into Sun angles utilizing a calibration polynomial. The micromachined mask comprises a 500-micron-thick silicon wafer, onto which is deposited a 57-nm-thick chromium adhesion- promotion layer followed by a 200-nm-thick gold light-absorption layer. The pinholes, 50 microns in diameter, are formed in the gold layer by photolithography. The chromium layer is thin enough to be penetrable by an amount of Sunlight adequate to form measurable pinhole images. A spacer frame between the mask and the APS maintains a gap of .1 mm between the pinhole plane and the photodetector plane of the APS. To minimize data volume, mass, and power consumption, the digital processing of the APS readouts takes place in a single field-programmable gate array (FPGA). The particular FPGA is a radiation- tolerant unit that contains .32,000 gates. No external memory is used so the FPGA calculates the centroids in real time as pixels are read off the APS with minimal internal memory. To enable the MSS to fit into a small package, the APS, the FPGA, and other components are mounted

  18. 30 CFR 75.1301 - Qualified person.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Explosives and Blasting § 75.1301 Qualified person. (a) A... for handling, loading, and preparing explosives for blasting and demonstrates to an...

  19. Simulation of Hypervelocity Impact on Aluminum-Nextel-Kevlar Orbital Debris Shields

    NASA Technical Reports Server (NTRS)

    Fahrenthold, Eric P.

    2000-01-01

    An improved hybrid particle-finite element method has been developed for hypervelocity impact simulation. The method combines the general contact-impact capabilities of particle codes with the true Lagrangian kinematics of large strain finite element formulations. Unlike some alternative schemes which couple Lagrangian finite element models with smooth particle hydrodynamics, the present formulation makes no use of slidelines or penalty forces. The method has been implemented in a parallel, three dimensional computer code. Simulations of three dimensional orbital debris impact problems using this parallel hybrid particle-finite element code, show good agreement with experiment and good speedup in parallel computation. The simulations included single and multi-plate shields as well as aluminum and composite shielding materials. at an impact velocity of eleven kilometers per second.

  20. Reliability Considerations for Composite Overwrapped Pressure Vessels on Spacecraft

    NASA Technical Reports Server (NTRS)

    Murthy, Pappu L. N.; Gyekenyesi, John P.; Grimes-Ledesma, Lorie; Phoenix, S. L.

    2007-01-01

    Composite Overwrapped Pressure Vessels (COPVs) are used to store gases under high pressure onboard spacecraft. These are used for a variety of purposes such as propelling liquid fuel etc, Kevlar, glass, Carbon and other more recent fibers have all been in use to overwrap the vessels. COPVs usually have a thin metallic liner with the primary purpose of containing the gases and prevent any leakage. The liner is overwrapped with filament wound composite such as Kevlar, Carbon or Glass fiber. Although the liner is required to perform in the leak before break mode making the failure a relatively benign mode, the overwrap can fail catastrophically under sustained load due to stress rupture. It is this failure mode that is of major concern as the stored energy of such vessels is often great enough ta cause loss of crew and vehicle. The present paper addresses some of the reliability concerns associated specifically with Kevlar Composite Overwrapped Pressure Vessels. The primary focus of the paper is on how reliability of COPV's are established for the purpose of deciding in general their flight worthiness and continued use. Analytical models based on existing design data will be presented showing how to achieve the required reliability metric to the end of a specific period of performance. Uncertainties in the design parameters and how they affect reliability and confidence intervals will be addressed as well. Some trade studies showing how reliability changes with time during a program period will be presented.

  1. Additional results on space environmental effects on polymer matrix composites: Experiment A0180

    NASA Technical Reports Server (NTRS)

    Tennyson, R. C.

    1992-01-01

    Additional experimental results on the atomic oxygen erosion of boron, Kevlar, and graphite fiber reinforced epoxy matrix composites are presented. Damage of composite laminates due to micrometeoroid/debris impacts is also examined with particular emphasis on the relationship between damage area and actual hole size due to particle penetration. Special attention is given to one micrometeoroid impact on an aluminum base plate which resulted in ejecta visible on an adjoining vertical flange structure.

  2. Torsional actuation with extension-torsion composite coupling and a magnetostrictive actuator

    NASA Astrophysics Data System (ADS)

    Bothwell, Christopher M.; Chandra, Ramesh; Chopra, Inderjit

    1995-04-01

    An analytical-experimental study of using magnetostrictive actuators in conjunction with an extension-torsion coupled composite tube to actuate a rotor blade trailing-edge flap to actively control helicopter vibration is presented. Thin walled beam analysis based on Vlasov theory was used to predict the induced twist and extension in a composite tube with magnetostrictive actuation. The study achieved good correlation between theory and experiment. The Kevlar-epoxy systems showed good correlation between measured and predicted twist values.

  3. Energy absorption of composite material and structure

    NASA Technical Reports Server (NTRS)

    Farley, Gary L.

    1987-01-01

    Results are presented from a joint research program on helicopter crashworthiness conducted by the U.S. Army Aerostructures Directorate and NASA Langley. Through the ongoing research program an in-depth understanding has been developed on the cause/effect relationships between material and architectural variables and the energy-absorption capability of composite material and structure. Composite materials were found to be efficient energy absorbers. Graphite/epoxy subfloor structures were more efficient energy absorbers than comparable structures fabricated from Kevlar or aluminum. An accurate method of predicting the energy-absorption capability of beams was developed.

  4. Infrared thermographic analysis of polymer composites during ballistic impact

    NASA Technical Reports Server (NTRS)

    Hsieh, C. Y.; Nagarajan, S.; Zee, R. H.

    1992-01-01

    An infrared thermographic system was used to measure the surface temperature profile of composite materials under ballistic impact. The heat deposited was calculated based on the temperature profiles. The extent of damage induced in the materials was determined qualitatively from the measured data. The relative contribution of frictional heat to total energy absorption was evaluated, and the effect of the shape of the projectile on the extent of damage and temperature distribution in the composites was examined. The results show that graphite and polyethylene composite are more effective than Kevlar composite in dissipating heat during the ballistic impact penetration process due to their higher thermal conductivity.

  5. Energy absorption in composite materials for crashworthy structures

    NASA Technical Reports Server (NTRS)

    Farley, Gary L.

    1987-01-01

    Crash energy-absorption processes in composite materials have been studied as part of a research program aimed at the development of energy absorbing subfloor beams for crashworthy military helicopters. Based on extensive tests on glass/epoxy, graphite/epoxy, and Kevlar/epoxy composites, it is shown that the energy-absorption characteristics and crushing modes of composite beams are similar to those exhibited by tubular specimens of similar material and architecture. The crushing mechanisms have been determined and related to the mechanical properties of the constituent materials and specimen architecture. A simple and accurate method for predicting the energy-absorption capability of composite beams has been developed.

  6. Transverse thermal expansion of carbon fiber/epoxy matrix composites

    NASA Technical Reports Server (NTRS)

    Helmer, J. F.; Diefendorf, R. J.

    1983-01-01

    Thermal expansion coefficients and moduli of elasticity have been determined experimentally for a series of epoxy-matrix composites reinforced with carbon and Kevlar fibers. It is found that in the transverse direction the difference between the properties of the fiber and the matrix is not as pronounced as in the longitudinal direction, where the composite properties are fiber-dominated. Therefore, the pattern of fiber packing tends to affect transverse composite properties. The transverse properties of the composites tested are examined from the standpoint of the concept of homogeneity defined as the variation of packing (or lack thereof) throughout a sample.

  7. 26 CFR 1.884-5 - Qualified resident.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 9 2010-04-01 2010-04-01 false Qualified resident. 1.884-5 Section 1.884-5 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Foreign Corporations § 1.884-5 Qualified resident. (a) Definition of qualified resident. A foreign corporation is a qualified...

  8. 30 CFR 75.155 - Qualified hoisting engineer; qualifications.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-hoisting engineer; or (2) If a State has no program for qualifying persons as electric-hoisting engineers... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Qualified hoisting engineer; qualifications. 75... Persons § 75.155 Qualified hoisting engineer; qualifications. (a)(1) A person is a qualified...

  9. 30 CFR 75.155 - Qualified hoisting engineer; qualifications.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-hoisting engineer; or (2) If a State has no program for qualifying persons as electric-hoisting engineers... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Qualified hoisting engineer; qualifications. 75... Persons § 75.155 Qualified hoisting engineer; qualifications. (a)(1) A person is a qualified...

  10. 30 CFR 75.155 - Qualified hoisting engineer; qualifications.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-hoisting engineer; or (2) If a State has no program for qualifying persons as electric-hoisting engineers... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Qualified hoisting engineer; qualifications. 75... Persons § 75.155 Qualified hoisting engineer; qualifications. (a)(1) A person is a qualified...

  11. 30 CFR 75.155 - Qualified hoisting engineer; qualifications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-hoisting engineer; or (2) If a State has no program for qualifying persons as electric-hoisting engineers... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Qualified hoisting engineer; qualifications. 75... Persons § 75.155 Qualified hoisting engineer; qualifications. (a)(1) A person is a qualified...

  12. 20 CFR 404.1018b - Medicare qualified government employment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Medicare qualified government employment. 404... Excluded from Employment § 404.1018b Medicare qualified government employment. (a) General. The work of a... constitute Medicare qualified government employment. Medicare qualified government employment means...

  13. 20 CFR 404.1018b - Medicare qualified government employment.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Medicare qualified government employment. 404... Excluded from Employment § 404.1018b Medicare qualified government employment. (a) General. The work of a... constitute Medicare qualified government employment. Medicare qualified government employment means...

  14. 20 CFR 404.1018b - Medicare qualified government employment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Medicare qualified government employment. 404... Excluded from Employment § 404.1018b Medicare qualified government employment. (a) General. The work of a... constitute Medicare qualified government employment. Medicare qualified government employment means...

  15. 26 CFR 25.2702-3 - Qualified interests.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 14 2010-04-01 2010-04-01 false Qualified interests. 25.2702-3 Section 25.2702... interests. (a) In general. This section provides rules for determining if an interest is a qualified annuity interest, a qualified unitrust interest, or a qualified remainder interest. (b) Special rules for...

  16. 33 CFR 155.1026 - Qualified individual and alternate qualified individual.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Qualified individual and alternate qualified individual. 155.1026 Section 155.1026 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS Tank Vessel Response Plans...

  17. Dynamic stress analysis of smooth and notched fiber composite flexural specimens

    NASA Technical Reports Server (NTRS)

    Murthy, P. L. N.; Chamis, C. C.

    1984-01-01

    A detailed analysis of the dynamic stress field in smooth and notched fiber composite (Charpy-type) specimens is reported in this paper. The analysis is performed with the aid of the direct transient response analysis solution sequence of MSC/NASTRAN. Three unidirectional composites were chosen for the study. They are S-Glass/Epoxy, Kevlar/Epoxy and T-300/Epoxy composite systems. The specimens are subjected to an impact load which is modeled as a triangular impulse with a maximum of 2000 lb and a duration of 1 ms. The results are compared with those of static analysis of the specimens subjected to a peak load of 2000 lb. For the geometry and type of materials studied, the static analysis results gave close conservative estimates for the dynamic stresses. Another interesting inference from the study is that the impact induced effects are felt by S-Glass/Epoxy specimens sooner than Kevlar/Epoxy or T-300/Epoxy specimens.

  18. Dynamic stress analysis of smooth and notched fiber composite flexural specimens

    NASA Technical Reports Server (NTRS)

    Murthy, P. L. N.; Chamis, C. C.

    1986-01-01

    A detailed analysis of the dynamic stress field in smooth and notched fiber composite (Charpy-type) specimens is reported in this paper. The analysis is performed with the aid of the direct transient response analysis solution sequence of MSC/NASTRAN. Three unidirectional composites were chosen for the study. They are S-Glass/Epoxy, Kevlar/Epoxy and T-300/Epoxy composite systems. The specimens are subjected to an impact load which is modeled as a triangular impulse with a maximum of 2000 lb and a duration of 1 ms. The results are compared with those of static analysis of the specimens subjected to a peak load of 2000 lb. For the geometry and type of materials studied, the static analysis results gave close conservative estimates for the dynamic stresses. Another interesting inference from the study is that the impact induced effects are felt by S-Glass/Epoxy specimens sooner than Kevlar/Epoxy or T-300/Epoxy specimens.

  19. Producibility aspects of advanced composites for an L-1011 Aileron

    NASA Technical Reports Server (NTRS)

    Van Hamersveld, J.; Fogg, L. D.

    1976-01-01

    The design of advanced composite aileron suitable for long-term service on transport aircraft includes Kevlar 49 fabric skins on honeycomb sandwich covers, hybrid graphite/Kevlar 49 ribs and spars, and graphite/epoxy fittings. Weight and cost savings of 28 and 20 percent, respectively, are predicted by comparison with the production metallic aileron. The structural integrity of the design has been substantiated by analysis and static tests of subcomponents. The producibility considerations played a key role in the selection of design concepts with potential for low-cost production. Simplicity in fabrication is a major factor in achieving low cost using advanced tooling and manufacturing methods such as net molding to size, draping, forming broadgoods, and cocuring components. A broadgoods dispensing machine capable of handling unidirectional and bidirectional prepreg materials in widths ranging from 12 to 42 inches is used for rapid layup of component kits and covers. Existing large autoclaves, platen presses, and shop facilities are fully exploited.

  20. Deposition, clearance, and shortening of Kevlar para-aramid fibrils in acute, subchronic, and chronic inhalation studies in rats.

    PubMed

    Kelly, D P; Merriman, E A; Kennedy, G L; Lee, K P

    1993-10-01

    The deposition and clearance of lung-deposited Kevlar para-aramid fibrils (subfibers) have been investigated as part of a subchronic and chronic inhalation toxicity testing program. Fibrils recovered from lung tissue in para-aramid-exposed Sprague-Dawley rats were microscopically counted and measured after exposures to airborne fibrils which were about 12 microns median length (ML) and < 0.3 micron median diameter. In each of three studies lung-recovered fibrils were progressively shorter with increasing residence time in the lungs. Twenty-eight days after a single 6-hr exposure at 400 respirable fibrils per cubic centimeter (f/cm3) the ML of recovered fibrils decreased to about 5 microns. Twenty-four months after a 3-week exposure to 25 or 400 f/cm3, fibrils reached about 2 microns ML. After 2 years of continuous exposure at 2.5, 25, or 100 f/cm3 or 1 year exposure plus 1 year recovery at 400 f/cm3, fibril ML approached 4 microns. In the 2-year study, the lung-fiber accumulation rate/exposure concentration was similar for the three highest concentrations and was about 3 x greater than that seen at 2.5 f/cm3, indicating that concentrations of about 25 f/cm3 or more may overwhelm clearance mechanisms. Time required for fibrils to be reduced to < 5 microns in the lung was markedly less at lower exposure concentration and shorter exposure time. The primary shortening mechanism is proposed to be long fibril cutting by enzymatic attack at fibril defects. However, length-selective fibril deposition and clearance may contribute to shortening in the first few days after exposure. The enzymatic cutting hypothesis is supported by measured increases in numbers of short fibers following cessation of exposures, continued shortening of the fibril length distribution up to 2 years following exposure, and in vitro fibril shortening after 3 months in a proteolytic enzyme preparation. The conclusion is that para-aramid fibrils are less durable in the lungs of rats than expected from

  1. 26 CFR 1.30-1 - Definition of qualified electric vehicle and recapture of credit for qualified electric vehicle.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 1 2013-04-01 2013-04-01 false Definition of qualified electric vehicle and recapture of credit for qualified electric vehicle. 1.30-1 Section 1.30-1 Internal Revenue INTERNAL REVENUE... qualified electric vehicle and recapture of credit for qualified electric vehicle. (a) Definition...

  2. 26 CFR 1.30-1 - Definition of qualified electric vehicle and recapture of credit for qualified electric vehicle.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 1 2011-04-01 2009-04-01 true Definition of qualified electric vehicle and recapture of credit for qualified electric vehicle. 1.30-1 Section 1.30-1 Internal Revenue INTERNAL REVENUE... qualified electric vehicle and recapture of credit for qualified electric vehicle. (a) Definition...

  3. 26 CFR 1.30-1 - Definition of qualified electric vehicle and recapture of credit for qualified electric vehicle.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 1 2012-04-01 2012-04-01 false Definition of qualified electric vehicle and recapture of credit for qualified electric vehicle. 1.30-1 Section 1.30-1 Internal Revenue INTERNAL REVENUE... qualified electric vehicle and recapture of credit for qualified electric vehicle. (a) Definition...

  4. 26 CFR 1.30-1 - Definition of qualified electric vehicle and recapture of credit for qualified electric vehicle.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 1 2010-04-01 2010-04-01 true Definition of qualified electric vehicle and recapture of credit for qualified electric vehicle. 1.30-1 Section 1.30-1 Internal Revenue INTERNAL REVENUE... qualified electric vehicle and recapture of credit for qualified electric vehicle. (a) Definition...

  5. 26 CFR 1.30-1 - Definition of qualified electric vehicle and recapture of credit for qualified electric vehicle.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 1 2014-04-01 2013-04-01 true Definition of qualified electric vehicle and recapture of credit for qualified electric vehicle. 1.30-1 Section 1.30-1 Internal Revenue INTERNAL REVENUE... qualified electric vehicle and recapture of credit for qualified electric vehicle. (a) Definition...

  6. Design prediction for long term stress rupture service of composite pressure vessels

    NASA Technical Reports Server (NTRS)

    Robinson, Ernest Y.

    1992-01-01

    Extensive stress rupture studies on glass composites and Kevlar composites were conducted by the Lawrence Radiation Laboratory beginning in the late 1960's and extending to about 8 years in some cases. Some of the data from these studies published over the years were incomplete or were tainted by spurious failures, such as grip slippage. Updated data sets were defined for both fiberglass and Kevlar composite stand test specimens. These updated data are analyzed in this report by a convenient form of the bivariate Weibull distribution, to establish a consistent set of design prediction charts that may be used as a conservative basis for predicting the stress rupture life of composite pressure vessels. The updated glass composite data exhibit an invariant Weibull modulus with lifetime. The data are analyzed in terms of homologous service load (referenced to the observed median strength). The equations relating life, homologous load, and probability are given, and corresponding design prediction charts are presented. A similar approach is taken for Kevlar composites, where the updated stand data do show a turndown tendency at long life accompanied by a corresponding change (increase) of the Weibull modulus. The turndown characteristic is not present in stress rupture test data of Kevlar pressure vessels. A modification of the stress rupture equations is presented to incorporate a latent, but limited, strength drop, and design prediction charts are presented that incorporate such behavior. The methods presented utilize Cartesian plots of the probability distributions (which are a more natural display for the design engineer), based on median normalized data that are independent of statistical parameters and are readily defined for any set of test data.

  7. Effect of Hybridization on Stiffness Properties of Woven Textile Composites

    NASA Astrophysics Data System (ADS)

    Bejan, Liliana; Taranu, Nicolae; Sîrbu, Adriana

    2013-04-01

    The present study focuses on stiffness properties of woven textile reinforced polymeric composites with respect to hybridization, and geometry of reinforcement. The analyzed composites represent combinations of different fibre materials (E-glass, Kevlar 49, carbon HM) in a predetermined fabric geometry (a plane weave embedded in thermosetting polymeric resin) serving controlled properties and required performance. The effects of hybridization on the stiffness properties of woven textile composites have been studied with respect to the fibres materials, the unbalancing degree of fabrics, and the variation of compactness and undulation of yarns. Some undesirable effects in fabric geometry can be overcome by the combined effects of hybridization and compactness.

  8. Structural monitoring of filamentary composites using embedded fiber optics

    NASA Technical Reports Server (NTRS)

    Cashon, John L.; Lehner, David L.; Bower, Mark V.; Gilbert, John A.

    1990-01-01

    The feasibility of monitoring overall integrity of structural components made of filamentary composites, by embedding optical fibers between lamina of a composite beam, is investigated using a beam constructed of Kevlar/epoxy cloth with embedded optical fibers aligned with the longitudinal axis of the beam. Phase changes were monitored in three different optical fibers as the composite beam was subjected to pure bending, and the strain response of the fibers was compared to the strain gage readings taken at the surface, showing a strong correlation between the phase change and the applied deformation.

  9. Revised State Plan for Highly Qualified Teachers

    ERIC Educational Resources Information Center

    Arizona Department of Education, 2006

    2006-01-01

    This State of Arizona Department of Education report addresses the following six requirements and contains supporting documents: (1) The revised plan must provide a detailed analysis of the core academic subject classes in the State that are currently not being taught by highly qualified teachers. The analysis must, in particular, address schools…

  10. 34 CFR 303.22 - Qualified.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 2 2010-07-01 2010-07-01 false Qualified. 303.22 Section 303.22 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF SPECIAL EDUCATION AND REHABILITATIVE SERVICES, DEPARTMENT OF EDUCATION EARLY INTERVENTION PROGRAM FOR INFANTS AND TODDLERS...

  11. 7 CFR 3431.15 - Qualifying loans.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... SERVICE, DEPARTMENT OF AGRICULTURE VETERINARY MEDICINE LOAN REPAYMENT PROGRAM Administration of the Veterinary Medicine Loan Repayment Program § 3431.15 Qualifying loans. (a) General. Loan repayments provided... accredited college of veterinary medicine resulting in a degree of Doctor of Veterinary Medicine, or...

  12. 7 CFR 4290.110 - Qualified management.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the knowledge, experience, and capability in Community Development Finance or Relevant Venture Capital... has sufficient qualifications, the Secretary will consider information provided by the Applicant and... 7 Agriculture 15 2010-01-01 2010-01-01 false Qualified management. 4290.110 Section...

  13. 13 CFR 108.110 - Qualified management.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 13 Business Credit and Assistance 1 2014-01-01 2014-01-01 false Qualified management. 108.110... management. An Applicant must show, to the satisfaction of SBA, that its current or proposed management team... or proposed management team has sufficient qualifications, SBA will consider information provided...

  14. 13 CFR 108.110 - Qualified management.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 13 Business Credit and Assistance 1 2012-01-01 2012-01-01 false Qualified management. 108.110... management. An Applicant must show, to the satisfaction of SBA, that its current or proposed management team... or proposed management team has sufficient qualifications, SBA will consider information provided...

  15. 13 CFR 108.110 - Qualified management.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 13 Business Credit and Assistance 1 2013-01-01 2013-01-01 false Qualified management. 108.110... management. An Applicant must show, to the satisfaction of SBA, that its current or proposed management team... or proposed management team has sufficient qualifications, SBA will consider information provided...

  16. 13 CFR 108.110 - Qualified management.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Qualified management. 108.110... management. An Applicant must show, to the satisfaction of SBA, that its current or proposed management team... or proposed management team has sufficient qualifications, SBA will consider information provided...

  17. 12 CFR 1808.200 - Qualified Issuers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Banks and Banking COMMUNITY DEVELOPMENT FINANCIAL INSTITUTIONS FUND, DEPARTMENT OF THE TREASURY COMMUNITY DEVELOPMENT FINANCIAL INSTITUTIONS BOND GUARANTEE PROGRAM Eligibility § 1808.200 Qualified Issuers... Guarantor will approve a Guarantee Application or issue a Guarantee. In order for the Guarantor to approve...

  18. 40 CFR 1400.12 - Qualified researchers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Qualified researchers. 1400.12 Section 1400.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY AND DEPARTMENT OF JUSTICE ACCIDENTAL RELEASE PREVENTION REQUIREMENTS; RISK MANAGEMENT PROGRAMS UNDER THE CLEAN AIR ACT SECTION...

  19. 7 CFR 802.1 - Qualified laboratories.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 7 2014-01-01 2014-01-01 false Qualified laboratories. 802.1 Section 802.1 Agriculture Regulations of the Department of Agriculture (Continued) GRAIN INSPECTION, PACKERS AND STOCKYARD ADMINISTRATION (FEDERAL GRAIN INSPECTION SERVICE), DEPARTMENT OF AGRICULTURE OFFICIAL PERFORMANCE AND...

  20. Does "Highly Qualified" Make You a "Star"?

    ERIC Educational Resources Information Center

    McKinney, Sueanne E.; Fuller, Sherell; Hancock, Stephen; Audette, Bob

    2006-01-01

    The No Child Left Behind Act of 2002 set forth to hold all schools accountable to high standards and address the long-standing objective of closing the achievement gap between students from high and low socioeconomic backgrounds. The guidelines and criteria that describe highly qualified teachers emphasize pedigrees and standardized test scores as…

  1. 40 CFR 1400.12 - Qualified researchers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Qualified researchers. 1400.12 Section 1400.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY AND DEPARTMENT OF JUSTICE ACCIDENTAL RELEASE PREVENTION REQUIREMENTS; RISK MANAGEMENT PROGRAMS UNDER THE CLEAN AIR ACT SECTION...

  2. 40 CFR 1400.12 - Qualified researchers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Qualified researchers. 1400.12 Section 1400.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY AND DEPARTMENT OF JUSTICE ACCIDENTAL RELEASE PREVENTION REQUIREMENTS; RISK MANAGEMENT PROGRAMS UNDER THE CLEAN AIR ACT SECTION...

  3. 40 CFR 1400.12 - Qualified researchers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Qualified researchers. 1400.12 Section 1400.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY AND DEPARTMENT OF JUSTICE ACCIDENTAL RELEASE PREVENTION REQUIREMENTS; RISK MANAGEMENT PROGRAMS UNDER THE CLEAN AIR ACT SECTION...

  4. 40 CFR 1400.12 - Qualified researchers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Qualified researchers. 1400.12 Section 1400.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY AND DEPARTMENT OF JUSTICE ACCIDENTAL RELEASE PREVENTION REQUIREMENTS; RISK MANAGEMENT PROGRAMS UNDER THE CLEAN AIR ACT SECTION...

  5. Profitability of Qualified-Labour-Power Production

    ERIC Educational Resources Information Center

    Baldino, Roberto Ribeiro; Cabral, Tânia Cristina Baptista

    2015-01-01

    In Baldino and Cabral (2013) we introduced the concept of qualified labour-power as the commodity produced by the school system. In the present article we outline a quantitative model to evaluate the profit rate of educational programmes. We compare a medical school programme with a teacher education programme at a public university in Brazil,…

  6. 7 CFR 802.1 - Qualified laboratories.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) GRAIN INSPECTION, PACKERS AND STOCKYARD ADMINISTRATION (FEDERAL GRAIN INSPECTION SERVICE), DEPARTMENT OF AGRICULTURE OFFICIAL PERFORMANCE AND PROCEDURAL REQUIREMENTS FOR GRAIN WEIGHING EQUIPMENT AND RELATED GRAIN HANDLING SYSTEMS § 802.1 Qualified laboratories....

  7. 27 CFR 479.68 - Qualified manufacturer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2012-04-01 2010-04-01 true Qualified manufacturer. 479.68 Section 479.68 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES, AND...

  8. 27 CFR 479.68 - Qualified manufacturer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2014-04-01 2014-04-01 false Qualified manufacturer. 479.68 Section 479.68 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES,...

  9. 27 CFR 479.68 - Qualified manufacturer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2011-04-01 2010-04-01 true Qualified manufacturer. 479.68 Section 479.68 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES, AND...

  10. 27 CFR 479.68 - Qualified manufacturer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2010-04-01 2010-04-01 false Qualified manufacturer. 479.68 Section 479.68 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES,...

  11. 27 CFR 479.68 - Qualified manufacturer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2013-04-01 2013-04-01 false Qualified manufacturer. 479.68 Section 479.68 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO, FIREARMS, AND EXPLOSIVES, DEPARTMENT OF JUSTICE FIREARMS AND AMMUNITION MACHINE GUNS, DESTRUCTIVE DEVICES,...

  12. Environmental effects on composite materials. Volume 3

    SciTech Connect

    Springer, G.S.

    1988-01-01

    The present collection of papers, each of which has previously been abstracted in International Aerospace Abstracts, discusses the accelerated environmental testing of composites, moisture solubility and diffusion in epoxy and epoxy-glass composites, the influence of internal and external factors affecting moisture absorption in polymer composites, long-tern moisture absorption in graphite/epoxy angle-ply laminates, the effect of UV light on Kevlar 49-reinforced composites, and temperature and moisture induced deformation in composite sandwich panels. Also discussed are the orthotropic thermoelastic problem of uniform heat flow distributed by a central crack, the effect of microcracks on composite laminate thermal expansion, the stress analysis of wooden structures exposed to elevated temperatures, and the deflection of plastic beams at elevated temperatures.

  13. Durability of aircraft composite materials

    NASA Technical Reports Server (NTRS)

    Dextern, H. B.

    1982-01-01

    Confidence in the long term durability of advanced composites is developed through a series of flight service programs. Service experience is obtained by installing secondary and primary composite components on commercial and military transport aircraft and helicopters. Included are spoilers, rudders, elevators, ailerons, fairings and wing boxes on transport aircraft and doors, fairings, tail rotors, vertical fins, and horizontal stabilizers on helicopters. Materials included in the evaluation are boron/epoxy, Kevlar/epoxy, graphite/epoxy and boron/aluminum. Inspection, maintenance, and repair results for the components in service are reported. The effects of long term exposure to laboratory, flight, and outdoor environmental conditions are reported for various composite materials. Included are effects of moisture absorption, ultraviolet radiation, and aircraft fuels and fluids.

  14. Composition.

    ERIC Educational Resources Information Center

    Nemanich, Donald, Ed.

    1974-01-01

    The articles in this special issue of the "Illinois English Bulletin" concern the state of composition instruction at the secondary and college levels. The titles and authors are "Monologues or Dialogues? A Plea for Literacy" by Dr. Alfred J. Lindsey, "Teaching Composition: Curiouser and Curiouser" by Denny Brandon, and "Teaching Writing to High…

  15. Characterization of multiaxial warp knit composites

    NASA Technical Reports Server (NTRS)

    Dexter, H. Benson; Hasko, Gregory H.; Cano, Roberto J.

    1991-01-01

    The objectives were to characterize the mechanical behavior and damage tolerance of two multiaxial warp knit fabrics to determine the acceptability of these fabrics for high performance composite applications. The tests performed included compression, tension, open hole compression, compression after impact and compression-compression fatigue. Tests were performed on as-fabricated fabrics and on multi-layer fabrics that were stitched together with either carbon or Kevlar stitching yarn. Results of processing studies for vacuum impregnation with Hercules 3501-6 epoxy resin and pressure impregnation with Dow Tactix 138/H41 epoxy resin and British Petroleum BP E905L epoxy resin are presented.

  16. A (13)C NMR analysis of the effects of electron radiation on graphite/polyetherimide composites

    NASA Technical Reports Server (NTRS)

    Ferguson, Milton W.

    1989-01-01

    Initial investigations have been made into the use of high resolution nuclear magnetic resonance (NMR) for the characterization of radiation effects in graphite and Kevlar fibers, polymers, and the fiber/matrix interface in graphite/polyetherimide composites. Sample preparation techniques were refined. Essential equipment has been procured. A new NMR probe was constructed to increase the proton signal-to-noise ratio. Problem areas have been identified and plans developed to resolve them.

  17. High-performance vessels from an aromatic polyamide fiber/epoxy composite

    NASA Technical Reports Server (NTRS)

    Chiao, T. T.; Hamstad, M. A.

    1975-01-01

    The investigation reported is concerned with the development of a filament-wound, ultralightweight composite vessel for the containment of cryogenic propellants and pressurant gases. The vessels are to be used within an operational temperature range from -253 C to ambient temperature. The fiber used for the process is Kevlar 49. The design and the fabrication of specimens and vessels are discussed along with the results obtained in a testing program.

  18. Stress analysis of advanced attack helicopter composite main rotor blade root end lug

    NASA Technical Reports Server (NTRS)

    Baker, D. J.

    1982-01-01

    Stress analysis of the Advanced Attack Helicopter (AAH) composite main rotor blade root end lug is described. The stress concentration factor determined from a finite element analysis is compared to an empirical value used in the lug design. The analysis and test data indicate that the stress concentration is primarily a function of configuration and independent of the range of material properties typical of Kevlar-49/epoxy and glass epoxy.

  19. Receptivity to Bariatric Surgery in Qualified Patients

    PubMed Central

    Fung, Michael; Wharton, Sean; Macpherson, Alison

    2016-01-01

    Objectives. Bariatric surgery has been shown to be an effective intervention for weight loss and diabetes management. Despite this, many patients qualified for bariatric surgery are not interested in undergoing the procedure. The objective of this study is to determine the factors influencing receptivity to bariatric surgery among those who qualify for the procedure. Methods. Patients attending a publicly funded weight management clinic who qualified for bariatric surgery were asked to complete an elective questionnaire between February 2013 and April 2014. Results. A total of 371 patients (72% female) completed the questionnaire. Only 87 of 371 (23%) participants were interested in bariatric surgery. Individuals interested in bariatric surgery had a higher BMI (48.0 versus 46.2 kg/m2, P = 0.03) and believed that they would lose more weight with surgery (51 versus 44 kg, P = 0.0069). Those who scored highly on past weight loss success and financial concerns were less likely to be interested in bariatric surgery, whereas those who scored highly on high receptivity to surgery and positive social support were more likely to be interested in bariatric surgery. Conclusion. Although participants overestimated the effect of bariatric surgery on weight loss, most were still not interested in bariatric surgery. PMID:27516900

  20. 26 CFR 1.25-3 - Qualified mortgage credit certificate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 1 2010-04-01 2010-04-01 true Qualified mortgage credit certificate. 1.25-3... TAXES Changes in Rates During A Taxable Year § 1.25-3 Qualified mortgage credit certificate. (a)-(g)(1... certificates for certain refinancings—(1) In general. If the issuer of a qualified mortgage credit...

  1. 26 CFR 1.25-3 - Qualified mortgage credit certificate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 1 2011-04-01 2009-04-01 true Qualified mortgage credit certificate. 1.25-3... TAXES Changes in Rates During A Taxable Year § 1.25-3 Qualified mortgage credit certificate. (a)-(g)(1... certificates for certain refinancings—(1) In general. If the issuer of a qualified mortgage credit...

  2. 26 CFR 1.25-3 - Qualified mortgage credit certificate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 1 2014-04-01 2013-04-01 true Qualified mortgage credit certificate. 1.25-3... TAXES Changes in Rates During A Taxable Year § 1.25-3 Qualified mortgage credit certificate. (a)-(g)(1... certificates for certain refinancings—(1) In general. If the issuer of a qualified mortgage credit...

  3. 46 CFR 4.03-6 - Qualified medical personnel.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Qualified medical personnel. 4.03-6 Section 4.03-6... AND INVESTIGATIONS Definitions § 4.03-6 Qualified medical personnel. The term qualified medical personnel means a physician, physician's assistant, nurse, emergency medical technician, or other...

  4. 26 CFR 1.42-18 - Qualified contracts.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 1 2013-04-01 2013-04-01 false Qualified contracts. 1.42-18 Section 1.42-18... Against Tax § 1.42-18 Qualified contracts. (a) Extended low-income housing commitment—(1) In general. No... building if the Agency is unable to present during such period a qualified contract for the acquisition...

  5. 49 CFR 604.7 - Qualified human service organizations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 7 2010-10-01 2010-10-01 false Qualified human service organizations. 604.7... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CHARTER SERVICE Exceptions § 604.7 Qualified human service organizations. (a) A recipient may provide charter service to a qualified human service organization (QHSO)...

  6. 42 CFR 436.121 - Qualified family members.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 4 2014-10-01 2014-10-01 false Qualified family members. 436.121 Section 436.121... Coverage of the Categorically Needy § 436.121 Qualified family members. (a) Definition. A qualified family member is any member of a family, including pregnant women and children eligible for Medicaid under §...

  7. 42 CFR 436.121 - Qualified family members.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 4 2012-10-01 2012-10-01 false Qualified family members. 436.121 Section 436.121... Coverage of the Categorically Needy § 436.121 Qualified family members. (a) Definition. A qualified family member is any member of a family, including pregnant women and children eligible for Medicaid under §...

  8. 42 CFR 436.121 - Qualified family members.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 4 2013-10-01 2013-10-01 false Qualified family members. 436.121 Section 436.121... Coverage of the Categorically Needy § 436.121 Qualified family members. (a) Definition. A qualified family member is any member of a family, including pregnant women and children eligible for Medicaid under §...

  9. 42 CFR 435.119 - Qualified family members.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 4 2012-10-01 2012-10-01 false Qualified family members. 435.119 Section 435.119... Family Members § 435.119 Qualified family members. (a) Definition. A qualified family member is any member of a family, including pregnant women and children eligible for Medicaid under § 435.116 of...

  10. 42 CFR 435.119 - Qualified family members.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 4 2011-10-01 2011-10-01 false Qualified family members. 435.119 Section 435.119... Family Members § 435.119 Qualified family members. (a) Definition. A qualified family member is any member of a family, including pregnant women and children eligible for Medicaid under § 435.116 of...

  11. 42 CFR 436.121 - Qualified family members.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Qualified family members. 436.121 Section 436.121... Coverage of the Categorically Needy § 436.121 Qualified family members. (a) Definition. A qualified family member is any member of a family, including pregnant women and children eligible for Medicaid under §...

  12. 42 CFR 435.119 - Qualified family members.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Qualified family members. 435.119 Section 435.119... Family Members § 435.119 Qualified family members. (a) Definition. A qualified family member is any member of a family, including pregnant women and children eligible for Medicaid under § 435.116 of...

  13. 42 CFR 436.121 - Qualified family members.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 4 2011-10-01 2011-10-01 false Qualified family members. 436.121 Section 436.121... Coverage of the Categorically Needy § 436.121 Qualified family members. (a) Definition. A qualified family member is any member of a family, including pregnant women and children eligible for Medicaid under §...

  14. 9 CFR 201.73 - Scale operators to be qualified.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 2 2014-01-01 2014-01-01 false Scale operators to be qualified. 201... ACT Services § 201.73 Scale operators to be qualified. Stockyard owners, market agencies, dealers, packers, and live poultry dealers shall employ qualified persons to operate scales for weighing...

  15. 9 CFR 201.73 - Scale operators to be qualified.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 2 2012-01-01 2012-01-01 false Scale operators to be qualified. 201... ACT Services § 201.73 Scale operators to be qualified. Stockyard owners, market agencies, dealers, packers, and live poultry dealers shall employ qualified persons to operate scales for weighing...

  16. 9 CFR 201.73 - Scale operators to be qualified.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 2 2013-01-01 2013-01-01 false Scale operators to be qualified. 201... ACT Services § 201.73 Scale operators to be qualified. Stockyard owners, market agencies, dealers, packers, and live poultry dealers shall employ qualified persons to operate scales for weighing...

  17. 9 CFR 201.73 - Scale operators to be qualified.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Scale operators to be qualified. 201... ACT Services § 201.73 Scale operators to be qualified. Stockyard owners, market agencies, dealers, packers, and live poultry dealers shall employ qualified persons to operate scales for weighing...

  18. 9 CFR 201.73 - Scale operators to be qualified.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 2 2011-01-01 2011-01-01 false Scale operators to be qualified. 201... ACT Services § 201.73 Scale operators to be qualified. Stockyard owners, market agencies, dealers, packers, and live poultry dealers shall employ qualified persons to operate scales for weighing...

  19. 7 CFR 1221.24 - Qualified sorghum producer organization.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 10 2014-01-01 2014-01-01 false Qualified sorghum producer organization. 1221.24... SORGHUM PROMOTION, RESEARCH, AND INFORMATION ORDER Sorghum Promotion, Research, and Information Order Definitions § 1221.24 Qualified sorghum producer organization. Qualified sorghum producer organization means...

  20. 7 CFR 1221.24 - Qualified sorghum producer organization.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 10 2012-01-01 2012-01-01 false Qualified sorghum producer organization. 1221.24... SORGHUM PROMOTION, RESEARCH, AND INFORMATION ORDER Sorghum Promotion, Research, and Information Order Definitions § 1221.24 Qualified sorghum producer organization. Qualified sorghum producer organization means...

  1. 7 CFR 1221.24 - Qualified sorghum producer organization.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Qualified sorghum producer organization. 1221.24... SORGHUM PROMOTION, RESEARCH, AND INFORMATION ORDER Sorghum Promotion, Research, and Information Order Definitions § 1221.24 Qualified sorghum producer organization. Qualified sorghum producer organization means...

  2. 7 CFR 1221.24 - Qualified sorghum producer organization.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 10 2013-01-01 2013-01-01 false Qualified sorghum producer organization. 1221.24... SORGHUM PROMOTION, RESEARCH, AND INFORMATION ORDER Sorghum Promotion, Research, and Information Order Definitions § 1221.24 Qualified sorghum producer organization. Qualified sorghum producer organization means...

  3. 7 CFR 701.110 - Qualifying minimum cost of restoration.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 7 2013-01-01 2013-01-01 false Qualifying minimum cost of restoration. 701.110... RESTORATION PROGRAM, AND CERTAIN RELATED PROGRAMS PREVIOUSLY ADMINISTERED UNDER THIS PART Emergency Conservation Program § 701.110 Qualifying minimum cost of restoration. (a) To qualify for assistance...

  4. 7 CFR 701.110 - Qualifying minimum cost of restoration.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 7 2011-01-01 2011-01-01 false Qualifying minimum cost of restoration. 701.110... RESTORATION PROGRAM, AND CERTAIN RELATED PROGRAMS PREVIOUSLY ADMINISTERED UNDER THIS PART Emergency Conservation Program § 701.110 Qualifying minimum cost of restoration. (a) To qualify for assistance...

  5. 7 CFR 701.110 - Qualifying minimum cost of restoration.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 7 2012-01-01 2012-01-01 false Qualifying minimum cost of restoration. 701.110... RESTORATION PROGRAM, AND CERTAIN RELATED PROGRAMS PREVIOUSLY ADMINISTERED UNDER THIS PART Emergency Conservation Program § 701.110 Qualifying minimum cost of restoration. (a) To qualify for assistance...

  6. 7 CFR 701.110 - Qualifying minimum cost of restoration.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 7 2014-01-01 2014-01-01 false Qualifying minimum cost of restoration. 701.110... RESTORATION PROGRAM, AND CERTAIN RELATED PROGRAMS PREVIOUSLY ADMINISTERED UNDER THIS PART Emergency Conservation Program § 701.110 Qualifying minimum cost of restoration. (a) To qualify for assistance...

  7. 7 CFR 701.10 - Qualifying minimum cost of restoration.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Qualifying minimum cost of restoration. 701.10 Section... RELATED PROGRAMS PREVIOUSLY ADMINISTERED UNDER THIS PART § 701.10 Qualifying minimum cost of restoration... restoration. Each affected State may be allowed to establish a higher minimum qualifying cost of...

  8. 28 CFR 41.32 - Qualified handicapped person.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Qualified handicapped person. 41.32..., NONDISCRIMINATION ON THE BASIS OF HANDICAP IN FEDERALLY ASSISTED PROGRAMS Standards for Determining Who Are Handicapped Persons § 41.32 Qualified handicapped person. Qualified handicapped person means: (a) With...

  9. 12 CFR 621.4 - Audit by qualified public accountant.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... selects a qualified public accountant to audit its financial statements and provide an opinion thereon for... generally accepted auditing standards. (b) The qualified public accountant's opinion of each institution's... disagrees with the opinion of a qualified public accountant required by paragraph (b) of this section,...

  10. 12 CFR 621.4 - Audit by qualified public accountant.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... selects a qualified public accountant to audit its financial statements and provide an opinion thereon for... generally accepted auditing standards. (b) The qualified public accountant's opinion of each institution's... disagrees with the opinion of a qualified public accountant required by paragraph (b) of this section,...

  11. 12 CFR 621.4 - Audit by qualified public accountant.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... selects a qualified public accountant to audit its financial statements and provide an opinion thereon for... generally accepted auditing standards. (b) The qualified public accountant's opinion of each institution's... disagrees with the opinion of a qualified public accountant required by paragraph (b) of this section,...

  12. 12 CFR 621.4 - Audit by qualified public accountant.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... selects a qualified public accountant to audit its financial statements and provide an opinion thereon for... generally accepted auditing standards. (b) The qualified public accountant's opinion of each institution's... disagrees with the opinion of a qualified public accountant required by paragraph (b) of this section,...

  13. 30 CFR 75.153 - Electrical work; qualified person.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electrical work; qualified person. 75.153....153 Electrical work; qualified person. (a) Except as provided in paragraph (f) of this section, an individual is a qualified person within the meaning of §§ 75.511 and 75.512 to perform electrical work...

  14. 30 CFR 75.153 - Electrical work; qualified person.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Electrical work; qualified person. 75.153....153 Electrical work; qualified person. (a) Except as provided in paragraph (f) of this section, an individual is a qualified person within the meaning of §§ 75.511 and 75.512 to perform electrical work...

  15. 30 CFR 75.153 - Electrical work; qualified person.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Electrical work; qualified person. 75.153....153 Electrical work; qualified person. (a) Except as provided in paragraph (f) of this section, an individual is a qualified person within the meaning of §§ 75.511 and 75.512 to perform electrical work...

  16. 30 CFR 77.103 - Electrical work; qualified person.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Electrical work; qualified person. 77.103... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Qualified and Certified Persons § 77.103 Electrical work; qualified person. (a) Except...

  17. 30 CFR 77.103 - Electrical work; qualified person.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Electrical work; qualified person. 77.103... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Qualified and Certified Persons § 77.103 Electrical work; qualified person. (a) Except...

  18. 30 CFR 77.103 - Electrical work; qualified person.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Electrical work; qualified person. 77.103... SAFETY AND HEALTH MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES Qualified and Certified Persons § 77.103 Electrical work; qualified person. (a) Except...

  19. 30 CFR 75.155 - Qualified hoisting engineer; qualifications.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Qualified hoisting engineer; qualifications. 75.155 Section 75.155 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Qualified and Certified Persons § 75.155 Qualified hoisting...

  20. 26 CFR 54.4980B-3 - Qualified beneficiaries.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 17 2012-04-01 2012-04-01 false Qualified beneficiaries. 54.4980B-3 Section 54.4980B-3 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) MISCELLANEOUS EXCISE TAXES (CONTINUED) PENSION EXCISE TAXES § 54.4980B-3 Qualified beneficiaries. The determination of who is a qualified beneficiary,...

  1. 38 CFR 21.6509 - Notice to qualified veterans.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2014-07-01 2014-07-01 false Notice to qualified veterans. 21.6509 Section 21.6509 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... Rehabilitation § 21.6509 Notice to qualified veterans. (a) At the time notice is provided to a qualified...

  2. 38 CFR 21.6509 - Notice to qualified veterans.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2013-07-01 2013-07-01 false Notice to qualified veterans. 21.6509 Section 21.6509 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... Rehabilitation § 21.6509 Notice to qualified veterans. (a) At the time notice is provided to a qualified...

  3. 38 CFR 21.6509 - Notice to qualified veterans.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Notice to qualified veterans. 21.6509 Section 21.6509 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... Rehabilitation § 21.6509 Notice to qualified veterans. (a) At the time notice is provided to a qualified...

  4. 38 CFR 21.6509 - Notice to qualified veterans.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2011-07-01 2011-07-01 false Notice to qualified veterans. 21.6509 Section 21.6509 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... Rehabilitation § 21.6509 Notice to qualified veterans. (a) At the time notice is provided to a qualified...

  5. 38 CFR 21.6509 - Notice to qualified veterans.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2012-07-01 2012-07-01 false Notice to qualified veterans. 21.6509 Section 21.6509 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... Rehabilitation § 21.6509 Notice to qualified veterans. (a) At the time notice is provided to a qualified...

  6. 26 CFR 1.132-3 - Qualified employee discounts.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Qualified employee discounts. 1.132-3 Section 1... employee discounts. (a) In general—(1) Definition. Gross income does not include the value of a qualified employee discount. A “qualified employee discount” is any employee discount with respect to...

  7. 46 CFR 4.03-6 - Qualified medical personnel.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Qualified medical personnel. 4.03-6 Section 4.03-6... AND INVESTIGATIONS Definitions § 4.03-6 Qualified medical personnel. The term qualified medical personnel means a physician, physician's assistant, nurse, emergency medical technician, or other...

  8. 46 CFR 4.03-6 - Qualified medical personnel.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Qualified medical personnel. 4.03-6 Section 4.03-6... AND INVESTIGATIONS Definitions § 4.03-6 Qualified medical personnel. The term qualified medical personnel means a physician, physician's assistant, nurse, emergency medical technician, or other...

  9. 36 CFR 908.13 - Rights of Qualified Persons.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Rights of Qualified Persons... PENNSYLVANIA AVENUE DEVELOPMENT AREA Preferential Right To Relocate § 908.13 Rights of Qualified Persons. (a... absolute right to return to the square where previous location was situated. (f) A Qualified...

  10. 26 CFR 1.127-2 - Qualified educational assistance program.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 2 2011-04-01 2011-04-01 false Qualified educational assistance program. 1.127... Qualified educational assistance program. (a) In general. A qualified educational assistance program is a plan established and maintained by an employer under which the employer provides educational...

  11. 26 CFR 54.4980B-4 - Qualifying events.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 17 2013-04-01 2013-04-01 false Qualifying events. 54.4980B-4 Section 54.4980B... EXCISE TAXES (CONTINUED) PENSION EXCISE TAXES § 54.4980B-4 Qualifying events. The determination of what constitutes a qualifying event is addressed in the following questions and answers: Q-1: What is a...

  12. 26 CFR 54.4980B-4 - Qualifying events.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 17 2012-04-01 2012-04-01 false Qualifying events. 54.4980B-4 Section 54.4980B... EXCISE TAXES (CONTINUED) PENSION EXCISE TAXES § 54.4980B-4 Qualifying events. The determination of what constitutes a qualifying event is addressed in the following questions and answers: Q-1: What is a...

  13. 26 CFR 54.4980B-4 - Qualifying events.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 17 2011-04-01 2011-04-01 false Qualifying events. 54.4980B-4 Section 54.4980B... EXCISE TAXES (CONTINUED) PENSION EXCISE TAXES § 54.4980B-4 Qualifying events. The determination of what constitutes a qualifying event is addressed in the following questions and answers: Q-1: What is a...

  14. 26 CFR 54.4980B-4 - Qualifying events.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 17 2014-04-01 2014-04-01 false Qualifying events. 54.4980B-4 Section 54.4980B... EXCISE TAXES (CONTINUED) PENSION EXCISE TAXES § 54.4980B-4 Qualifying events. The determination of what constitutes a qualifying event is addressed in the following questions and answers: Q-1: What is a...

  15. 26 CFR 54.4980B-4 - Qualifying events.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 17 2010-04-01 2010-04-01 false Qualifying events. 54.4980B-4 Section 54.4980B... EXCISE TAXES (CONTINUED) PENSION EXCISE TAXES § 54.4980B-4 Qualifying events. The determination of what constitutes a qualifying event is addressed in the following questions and answers: Q-1: What is a...

  16. 11 CFR 9002.11 - Qualified campaign expense.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 11 Federal Elections 1 2010-01-01 2010-01-01 false Qualified campaign expense. 9002.11 Section 9002.11 Federal Elections FEDERAL ELECTION COMMISSION PRESIDENTIAL ELECTION CAMPAIGN FUND: GENERAL ELECTION FINANCING DEFINITIONS § 9002.11 Qualified campaign expense. (a) Qualified campaign expense means any expenditure, including a purchase,...

  17. 5 CFR 2634.403 - Qualified blind trusts.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 5 Administrative Personnel 3 2012-01-01 2012-01-01 false Qualified blind trusts. 2634.403 Section... Qualified blind trusts. (a) Definition. A qualified blind trust is a trust in which the filer, his spouse... instrument which establishes a blind trust must adhere substantively to model drafts circulated by the...

  18. 5 CFR 2634.403 - Qualified blind trusts.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 5 Administrative Personnel 3 2011-01-01 2011-01-01 false Qualified blind trusts. 2634.403 Section... Qualified blind trusts. (a) Definition. A qualified blind trust is a trust in which the filer, his spouse... instrument which establishes a blind trust must adhere substantively to model drafts circulated by the...

  19. 7 CFR 1221.24 - Qualified sorghum producer organization.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Qualified sorghum producer organization. 1221.24... SORGHUM PROMOTION, RESEARCH, AND INFORMATION ORDER Sorghum Promotion, Research, and Information Order Definitions § 1221.24 Qualified sorghum producer organization. Qualified sorghum producer organization means...

  20. 26 CFR 25.2702-3 - Qualified interests.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 14 2011-04-01 2010-04-01 true Qualified interests. 25.2702-3 Section 25.2702-3... GIFT TAX; GIFTS MADE AFTER DECEMBER 31, 1954 Special Valuation Rules § 25.2702-3 Qualified interests. (a) In general. This section provides rules for determining if an interest is a qualified...

  1. 49 CFR 604.7 - Qualified human service organizations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Qualified human service organizations. 604.7... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CHARTER SERVICE Exceptions § 604.7 Qualified human service organizations. (a) A recipient may provide charter service to a qualified human service organization (QHSO)...

  2. 49 CFR 604.7 - Qualified human service organizations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 7 2012-10-01 2012-10-01 false Qualified human service organizations. 604.7... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CHARTER SERVICE Exceptions § 604.7 Qualified human service organizations. (a) A recipient may provide charter service to a qualified human service organization (QHSO)...

  3. 49 CFR 604.7 - Qualified human service organizations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 7 2014-10-01 2014-10-01 false Qualified human service organizations. 604.7... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CHARTER SERVICE Exceptions § 604.7 Qualified human service organizations. (a) A recipient may provide charter service to a qualified human service organization (QHSO)...

  4. 49 CFR 604.7 - Qualified human service organizations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Qualified human service organizations. 604.7... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CHARTER SERVICE Exceptions § 604.7 Qualified human service organizations. (a) A recipient may provide charter service to a qualified human service organization (QHSO)...

  5. 26 CFR 1.132-9 - Qualified transportation fringes.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 2 2011-04-01 2011-04-01 false Qualified transportation fringes. 1.132-9... Qualified transportation fringes. (a) Table of contents. This section contains a list of the questions and answers in § 1.132-9. (1) General rules. Q-1. What is a qualified transportation fringe? Q-2. What...

  6. 26 CFR 1.132-9 - Qualified transportation fringes.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 2 2013-04-01 2013-04-01 false Qualified transportation fringes. 1.132-9... Qualified transportation fringes. (a) Table of contents. This section contains a list of the questions and answers in § 1.132-9. (1) General rules. Q-1. What is a qualified transportation fringe? Q-2. What...

  7. 26 CFR 1.132-9 - Qualified transportation fringes.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 2 2014-04-01 2014-04-01 false Qualified transportation fringes. 1.132-9... Qualified transportation fringes. (a) Table of contents. This section contains a list of the questions and answers in § 1.132-9. (1) General rules. Q-1. What is a qualified transportation fringe? Q-2. What...

  8. 26 CFR 1.132-9 - Qualified transportation fringes.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Qualified transportation fringes. 1.132-9... Qualified transportation fringes. (a) Table of contents. This section contains a list of the questions and answers in § 1.132-9. (1) General rules. Q-1. What is a qualified transportation fringe? Q-2. What...

  9. 26 CFR 1.132-9 - Qualified transportation fringes.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 2 2012-04-01 2012-04-01 false Qualified transportation fringes. 1.132-9... Qualified transportation fringes. (a) Table of contents. This section contains a list of the questions and answers in § 1.132-9. (1) General rules. Q-1. What is a qualified transportation fringe? Q-2. What...

  10. 21 CFR 516.141 - Qualified expert panels.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... of a qualified expert panel. Establishing a qualified expert panel is the first step in the process... expert panel member may not be an FDA employee. (4) A qualified expert panel must have at least three... panel meets the selection criteria listed in paragraphs (b)(1) through (b)(5) of this section. (3)...

  11. Composites

    SciTech Connect

    Chou, T.; McCullough, R.L.; Pipes, R.B.

    1986-10-01

    The degree of control over material properties that is typified by hybrid composites is transforming engineering design. In part because homogeneous materials such as metals and alloys do not offer comparable control, specifying a material and designing a component have traditionally taken place separately. As composites begin to replace traditional materials in fields and such as aerospace, component design and the specification of a material are merging and becoming aspects of a single process. The controllable microstructure of a composite allows it to be tailored to match the distribution of stresses to which it will be subject. At the same time components must come to reflect the distinctive nature of composites: their directional properties and the intricate forms they can be given through processes such as injection molding, filament winding and three-dimensional weaving. The complexity inherent in conceiving components and their materials at the same time suggests engineering design will grow increasingly dependent on computers and multidisciplinary teams. Such an approach will harness the full potential of composites for the technologies of the future. 10 figures.

  12. Terahertz NDE of Stressed Composite Overwrapped Pressure Vessels - Initial Testing

    NASA Technical Reports Server (NTRS)

    Madaras, Eric I.; Seebo, Jeffrey P.; Anatasi, Robert F.

    2009-01-01

    Terahertz radiation nondestructive evaluation was applied to a set of Kevlar composite overwrapped pressure vessel bottles that had undergone a series of thermal and pressure tests to simulate stress rupture effects. The bottles in these nondestructive evaluation tests were bottles that had not ruptured but had survived various times at the elevated load and temperature levels. Some of the bottles showed evidence of minor composite failures. The terahertz radiation did detect visible surface flaws, but did not detect any internal chemical or material degradation of the thin overwraps.

  13. Acoustic method of damage sensing in composite materials

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.; Walker, James; Lansing, Matthew

    1994-01-01

    The use of acoustic emission and acousto-ultrasonics to characterize impact damage in composite structures is being performed on both graphite epoxy and kevlar bottles. Further development of the acoustic emission methodology to include neural net analysis and/or other multivariate techniques will enhance the capability of the technique to identify failure mechanisms during fracture. The acousto-ultrasonics technique will be investigated to determine its ability to predict regions prone to failure prior to the burst tests. The combination of the two methods will allow for simple nondestructive tests to be capable of predicting the performance of a composite structure prior to being placed in service and during service.

  14. Response of polymer composites to high and low velocity impact

    NASA Technical Reports Server (NTRS)

    Hsieh, C. Y.; Mount, A.; Jang, B. Z.; Zee, R. H.

    1990-01-01

    The present investigation of fiber-reinforced polymer matrix composites' impact characteristics employed a drop tower for the low-velocity impact case and a novel, projectile instantaneous velocity-measuring sensor for high-velocity impact. Attention was given to the energy loss of projectiles in composites reinforced with polyethylene, kevlar, and graphite. Two distinct energy-loss mechanisms are noted, the first of which is due to the actual fracture process while the other is due to the generation of friction heat. The drop-tower impact-test results furnish the strain-rate dependence of the energy loss.

  15. Mechanical property characterization of intraply hybrid composites

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Lark, R. F.; Sinclair, J. H.

    1979-01-01

    An investigation of the mechanical properties of intraply hybrids made from graphite fiber/epoxy matrix hybridized with secondary S-glass or Kevlar 49 fiber composites is presented. The specimen stress-strain behavior was determined, showing that mechanical properties of intraply hybrid composites can be measured with available methods such as the ten-degree off-axis test for intralaminar shear, and conventional tests for tensile, flexure, and Izod impact properties. The results also showed that combinations of high modulus graphite/S-glass/epoxy matrix composites exist which yield intraply hybrid laminates with the best 'balanced' properties, and that the translation efficiency of mechanical properties from the constituent composites to intraply hybrids may be assessed with a simple equation.

  16. Composites

    NASA Astrophysics Data System (ADS)

    Taylor, John G.

    The Composites market is arguably the most challenging and profitable market for phenolic resins aside from electronics. The variety of products and processes encountered creates the challenges, and the demand for high performance in critical operations brings value. Phenolic composite materials are rendered into a wide range of components to supply a diverse and fragmented commercial base that includes customers in aerospace (Space Shuttle), aircraft (interiors and brakes), mass transit (interiors), defense (blast protection), marine, mine ducting, off-shore (ducts and grating) and infrastructure (architectural) to name a few. For example, phenolic resin is a critical adhesive in the manufacture of honeycomb sandwich panels. Various solvent and water based resins are described along with resin characteristics and the role of metal ions for enhanced thermal stability of the resin used to coat the honeycomb. Featured new developments include pultrusion of phenolic grating, success in RTM/VARTM fabricated parts, new ballistic developments for military vehicles and high char yield carbon-carbon composites along with many others. Additionally, global regional market resin volumes and sales are presented and compared with other thermosetting resin systems.

  17. Space-Qualified Traveling-Wave Tube

    NASA Technical Reports Server (NTRS)

    Wilson, Jeffrey D.; Krawczyk, Richard; Simons, Rainee N.; Williams, Wallace D.; Robbins, Neal R.; Dibb, Daniel R.; Menninger, William L.; Zhai, Xiaoling; Benton, Robert T.

    2010-01-01

    The L-3 Communications Electron Technologies, Inc. Model 999HA traveling-wave tube (TWT), was developed for use as a high-power microwave amplifier for high-rate transmission of data and video signals from deep space to Earth (see figure). The 999HA is a successor to the 999H a non-space qualified TWT described in High-Power, High-Efficiency Ka-Band Traveling-Wave Tube (LEW-17900-1), NASA Tech Briefs, Vol. 31, No. 2 (February 2007), page 32. Operating in the 31.8-to-32.3 GHz frequency band, the 999HA has been shown to generate 252 W of continuous- wave output power at 62 percent overall power efficiency a 75-percent increase in output power over the 999H. The mass of the 999HA is 35 percent less than that of the 999H. Moreover, taking account of the elimination of a Faraday cage that is necessary for operation of the 999H but is obviated by a redesign of high-voltage feed-throughs for the 999HA, the overall reduction in mass becomes 57 percent with an 82 percent reduction in volume. Through a series of rigorous tests, the 999HA has been qualified for operation aboard spacecraft with a lifetime exceeding seven years. Offspring of the 999HA will fly on the Kepler and Lunar Reconnaissance Orbiter missions.

  18. Composites

    NASA Astrophysics Data System (ADS)

    Chmielewski, M.; Nosewicz, S.; Pietrzak, K.; Rojek, J.; Strojny-Nędza, A.; Mackiewicz, S.; Dutkiewicz, J.

    2014-11-01

    It is commonly known that the properties of sintered materials are strongly related to technological conditions of the densification process. This paper shows the sintering behavior of a NiAl-Al2O3 composite, and its individual components sintered separately. Each kind of material was processed via the powder metallurgy route (hot pressing). The progress of sintering at different stages of the process was tested. Changes in the microstructure were examined using scanning and transmission electron microscopy. Metal-ceramics interface was clean and no additional phases were detected. Correlation between the microstructure, density, and mechanical properties of the sintered materials was analyzed. The values of elastic constants of NiAl/Al2O3 were close to intermetallic ones due to the volume content of the NiAl phase particularly at low densities, where small alumina particles had no impact on the composite's stiffness. The influence of the external pressure of 30 MPa seemed crucial for obtaining satisfactory stiffness for three kinds of the studied materials which were characterized by a high dense microstructure with a low number of isolated spherical pores.

  19. Design of a unidirectional composite momentum wheel rim

    NASA Technical Reports Server (NTRS)

    Shogrin, Bradley; Jones, William R., Jr.; Prahl, Joseph M.

    1995-01-01

    A preliminary study comparing twelve unidirectional-fiber composite systems to five metal materials conventionally used in momentum wheels is presented. Six different fibers are considered in the study: E-Glass, S-Glass, Boron, AS, T300, and Kevlar. Because of the possibility of high momentum requirements, and thus high stresses, only two matrix materials are considered: a high-modulus (HM) and a intermediate-modulus-high-strength (IMHS) matrix. Each of the six fibers are coupled with each of the two matrix materials. In an effort to optimize the composite system, each composite is considered while varying the fiber volume ratio from 0.0 to 0.7 in increments of 0.1. For fiber volume ratios above 0.2, all twelve unidirectional-fiber composite systems meet the study's requirements with higher factors of safety and less mass than the five conventional isotropic (metal) materials. For example, at a fiber volume ratio of 0.6, the Kevlar/IMHS composite system has a safety factor 4.5 times greater than that of a steel (maraging) system and an approximately 10 percent reduction in weight.

  20. Design of a unidirectional composite momentum wheel rim

    NASA Astrophysics Data System (ADS)

    Shogrin, Bradley; Jones, William R., Jr.; Prahl, Joseph M.

    1995-05-01

    A preliminary study comparing twelve unidirectional-fiber composite systems to five metal materials conventionally used in momentum wheels is presented. Six different fibers are considered in the study: E-Glass, S-Glass, Boron, AS, T300, and Kevlar. Because of the possibility of high momentum requirements, and thus high stresses, only two matrix materials are considered: a high-modulus (HM) and a intermediate-modulus-high-strength (IMHS) matrix. Each of the six fibers are coupled with each of the two matrix materials. In an effort to optimize the composite system, each composite is considered while varying the fiber volume ratio from 0.0 to 0.7 in increments of 0.1. For fiber volume ratios above 0.2, all twelve unidirectional-fiber composite systems meet the study's requirements with higher factors of safety and less mass than the five conventional isotropic (metal) materials. For example, at a fiber volume ratio of 0.6, the Kevlar/IMHS composite system has a safety factor 4.5 times greater than that of a steel (maraging) system and an approximately 10 percent reduction in weight.

  1. Experimental-theoretical investigation of the vibration characteristics of rotating composite box beams

    NASA Astrophysics Data System (ADS)

    Chandra, Ramesh; Chopra, Inderjit

    1992-08-01

    The objective of the study was to predict the effect of elastic couplings on the free vibration characteristics of thin-walled composite box beams and to correlate the results with experimental data. The free vibration characteristics of coupled thin-walled composite beams under rotation were determined using the Galerkin method. The theoretical results were found to be in satisfactory agreement with experimental data obtained for graphite/epoxy, kevlar/epoxy, and glass/epoxy composite beams in an in-vacuo test facility at different rotational speeds.

  2. 49 CFR 109.11 - Assistance of properly qualified personnel.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS AND OIL TRANSPORTATION... properly qualified to perform a function that is essential to the agent's exercise of authority under...

  3. 42 CFR 417.410 - Qualifying conditions: General rules.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... groups and to deliver a specified comprehensive range of high quality services efficiently, effectively... services, and a quality assurance program. (c) Standards. Generally, each qualifying condition...

  4. 42 CFR 417.410 - Qualifying conditions: General rules.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... groups and to deliver a specified comprehensive range of high quality services efficiently, effectively... services, and a quality assurance program. (c) Standards. Generally, each qualifying condition...

  5. Durability of commercial aircraft and helicopter composite structures

    NASA Technical Reports Server (NTRS)

    Dexter, H. B.

    1982-01-01

    The development of advanced composite technology during the past decade is discussed. Both secondary and primary components fabricated with boron, graphite, and Kevlar composites are evaluated. Included are spoilers, rudders, and fairings on commercial transports, boron/epoxy reinforced wing structure on C-130 military transports, and doors, fairings, tail rotors, vertical fins, and horizontal stabilizers on commercial helicopters. The development of composite structures resulted in advances in design and manufacturing technology for secondary and primary composite structures for commercial transports. Design concepts and inspection and maintenance results for the components in service are reported. The flight, outdoor ground, and controlled laboratory environmental effects on composites were also determined. Effects of moisture absorption, ultraviolet radiation, aircraft fuels and fluids, and sustained tensile stress are included. Critical parameters affecting the long term durability of composite materials are identified.

  6. Experimental investigation of the crashworthiness of scaled composite sailplane fuselages

    NASA Technical Reports Server (NTRS)

    Kampf, Karl-Peter; Crawley, Edward F.; Hansman, R. John, Jr.

    1989-01-01

    The crash dynamics and energy absorption of composite sailplane fuselage segments undergoing nose-down impact were investigated. More than 10 quarter-scale structurally similar test articles, typical of high-performance sailplane designs, were tested. Fuselages segments were fabricated of combinations of fiberglass, graphite, Kevlar, and Spectra fabric materials. Quasistatic and dynamic tests were conducted. The quasistatic tests were found to replicate the strain history and failure modes observed in the dynamic tests. Failure modes of the quarter-scale model were qualitatively compared with full-scale crash evidence and quantitatively compared with current design criteria. By combining material and structural improvements, substantial increases in crashworthiness were demonstrated.

  7. Progress report 3 of cooperative program for design, fabrication, and testing of high modulus composite helicopter shafting

    NASA Technical Reports Server (NTRS)

    Wright, C. C.; Baker, D. J.

    1980-01-01

    This report describes the third phase of work, the objective of which was to overcome the excessive brittleness of the previously developed UH-1 helicopter tail rotor drive shaft design which demonstrated a shaft train weight savings of 53.1% over the current 2024-T3 aluminum shaft train. A materials impact program demonstrated exceptionally noteworthy performance of two woven constructions containing E-glass and PRD 49-III (designation later changed to KEVLAR 49) fibers in an epoxy resin matrix. Thermoplastic matrices and PRD 49-III fiber provided impact resistance at low weight which was superior to composites having the same fiber in a thermoset resin matrix. A design, fabrication, and test program showed that shaft impact resistance could be improved over the previously developed graphite composite design at a cost in shaft train rate savings. The shaft train weight savings of the most impact tolerant construction was 4.0% over the current aluminum shaft train. Alternating plies of graphite and glass appear to provide substantially greater tube impact durability than that provided by hybridization of the two fibers into one tape wound to a ply design equivalent in strength and stiffness to that of the alternating ply design. Recommendations were made to continue research work to exploit the potential for more impact-durable structures through the use of KEVLAR 49 fiber, woven structures, thermoplastic matrices and THORNEL 50-S/KEVLAR 49 blends with thermoset matrices.

  8. Study to investigate design, fabrication and test of low cost concepts for large hybrid composite helicopter fuselage, phase 1

    NASA Technical Reports Server (NTRS)

    Adams, K. M.; Lucas, J. J.

    1975-01-01

    The development of a frame/stringer/skin fabrication technique for composite airframe construction was studied as a low cost approach to the manufacture of large helicopter airframe components. A center cabin aluminum airframe section of the Sikorsky CH-53D helicopter was selected for evaluation as a composite structure. The design, as developed, is composed of a woven KEVLAR-49/epoxy skin and graphite/epoxy frames and stringers. To support the selection of this specific design concept a materials study was conducted to develop and select a cure compatible graphite and KEVLAR-49/epoxy resin system, and a foam system capable of maintaining shape and integrity under the processing conditions established. The materials selected were, Narmco 5209/Thornel T-300 graphite, Narmco 5209/KEVLAR-49 woven fabric, and Stathane 8747 polyurethane foam. Eight specimens were fabricated, representative of the frame, stringer, and splice joint attachments. Evaluation of the results of analysis and test indicate that design predictions are good to excellent except for some conservatism of the complex frame splice.

  9. Bayesian kriging - merging observations and qualified guesses in kriging

    SciTech Connect

    Omre, H.

    1987-01-01

    Frequently a user wants to merge general knowledge of the regionalized variable under study with available observations. Introduction of fake observations is the usual way of doing this. Bayesian kriging allows the user to specify a qualified guess, associated with uncertainty, for the expected surface. The method will provide predictions which are based on both observations and this qualified guess.

  10. 7 CFR 900.356 - Listing of qualified associations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Listing of qualified associations. 900.356 Section 900... REGULATIONS Procedure for Determining the Qualification of Cooperative Milk Marketing Associations § 900.356 Listing of qualified associations. A copy of each determination of qualification is furnished to...

  11. 7 CFR 900.356 - Listing of qualified associations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 8 2011-01-01 2011-01-01 false Listing of qualified associations. 900.356 Section 900... REGULATIONS Procedure for Determining the Qualification of Cooperative Milk Marketing Associations § 900.356 Listing of qualified associations. A copy of each determination of qualification is furnished to...

  12. 26 CFR 26.2642-6 - Qualified severance.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 14 2014-04-01 2013-04-01 true Qualified severance. 26.2642-6 Section 26.2642-6 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) ESTATE AND GIFT TAXES GENERATION-SKIPPING TRANSFER TAX REGULATIONS UNDER THE TAX REFORM ACT OF 1986 § 26.2642-6 Qualified severance. (a) In general. If a trust...

  13. 26 CFR 1.1092(c)-1 - Qualified covered calls.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 11 2010-04-01 2010-04-01 true Qualified covered calls. 1.1092(c)-1 Section 1.1092(c)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Wash Sales of Stock Or Securities § 1.1092(c)-1 Qualified covered calls. (a)...

  14. Enhancing the Employability of Newly Qualified Nurses: A Pilot Study

    ERIC Educational Resources Information Center

    Dray, Beattie; Burke, Linda; Hurst, Heather M.; Ferguson, Anne; Marks-Maran, Diane

    2011-01-01

    Vocationally based higher education programmes are meant to prepare people for employment in their chosen fields of study. In nursing, historically, employment after qualifying has been almost assured, with sufficient vacancies available for newly qualified nurses. Recently, however, for a number of reasons, primarily related to economic…

  15. 7 CFR 1260.115 - Qualified State beef council.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Qualified State beef council. 1260.115 Section 1260... SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE BEEF PROMOTION AND RESEARCH Beef Promotion and Research Order Definitions § 1260.115 Qualified State beef...

  16. 7 CFR 1260.115 - Qualified State beef council.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Qualified State beef council. 1260.115 Section 1260... SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE BEEF PROMOTION AND RESEARCH Beef Promotion and Research Order Definitions § 1260.115 Qualified State beef...

  17. 7 CFR 1260.181 - Qualified State beef councils.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Qualified State beef councils. 1260.181 Section 1260... SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE BEEF PROMOTION AND RESEARCH Beef Promotion and Research Order Assessments § 1260.181 Qualified State...

  18. 14 CFR 60.17 - Previously qualified FSTDs.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Previously qualified FSTDs. 60.17 Section 60.17 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRMEN FLIGHT SIMULATION TRAINING DEVICE INITIAL AND CONTINUING QUALIFICATION AND USE § 60.17 Previously qualified FSTDs. (a) Unless...

  19. 7 CFR 1220.313 - Qualified State Soybean Boards.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Qualified State Soybean Boards. 1220.313 Section 1220... SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SOYBEAN... Soybean Boards. The following State soybean promotion organizations shall be Qualified State...

  20. 7 CFR 1220.313 - Qualified State Soybean Boards.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Qualified State Soybean Boards. 1220.313 Section 1220... SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SOYBEAN... Soybean Boards. The following State soybean promotion organizations shall be Qualified State...

  1. 7 CFR 1220.313 - Qualified State Soybean Boards.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 10 2013-01-01 2013-01-01 false Qualified State Soybean Boards. 1220.313 Section 1220... SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SOYBEAN... Soybean Boards. The following State soybean promotion organizations shall be Qualified State...

  2. 7 CFR 1220.313 - Qualified State Soybean Boards.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 10 2014-01-01 2014-01-01 false Qualified State Soybean Boards. 1220.313 Section 1220... SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SOYBEAN... Soybean Boards. The following State soybean promotion organizations shall be Qualified State...

  3. 7 CFR 1220.313 - Qualified State Soybean Boards.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 10 2012-01-01 2012-01-01 false Qualified State Soybean Boards. 1220.313 Section 1220... SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE SOYBEAN... Soybean Boards. The following State soybean promotion organizations shall be Qualified State...

  4. 26 CFR 1.42-17 - Qualified allocation plan.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 1 2014-04-01 2013-04-01 true Qualified allocation plan. 1.42-17 Section 1.42... Credits Against Tax § 1.42-17 Qualified allocation plan. (a) Requirements—(1) In general. (2) Selection..., rent-up and marketing costs, accounting and auditing costs, working capital and operating...

  5. 26 CFR 1.42-17 - Qualified allocation plan.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 1 2011-04-01 2009-04-01 true Qualified allocation plan. 1.42-17 Section 1.42... Credits Against Tax § 1.42-17 Qualified allocation plan. (a) Requirements—(1) In general. (2) Selection..., rent-up and marketing costs, accounting and auditing costs, working capital and operating...

  6. 26 CFR 1.42-17 - Qualified allocation plan.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 1 2010-04-01 2010-04-01 true Qualified allocation plan. 1.42-17 Section 1.42... Credits Against Tax § 1.42-17 Qualified allocation plan. (a) Requirements—(1) In general. (2) Selection..., rent-up and marketing costs, accounting and auditing costs, working capital and operating...

  7. 26 CFR 1.42-17 - Qualified allocation plan.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 1 2012-04-01 2012-04-01 false Qualified allocation plan. 1.42-17 Section 1.42... Credits Against Tax § 1.42-17 Qualified allocation plan. (a) Requirements—(1) In general. (2) Selection..., rent-up and marketing costs, accounting and auditing costs, working capital and operating...

  8. 26 CFR 1.42-17 - Qualified allocation plan.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 1 2013-04-01 2013-04-01 false Qualified allocation plan. 1.42-17 Section 1.42... Credits Against Tax § 1.42-17 Qualified allocation plan. (a) Requirements—(1) In general. (2) Selection..., rent-up and marketing costs, accounting and auditing costs, working capital and operating...

  9. 26 CFR 26.2642-6 - Qualified severance.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 14 2010-04-01 2010-04-01 false Qualified severance. 26.2642-6 Section 26.2642-6 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) ESTATE AND GIFT TAXES GENERATION-SKIPPING TRANSFER TAX REGULATIONS UNDER THE TAX REFORM ACT OF 1986 § 26.2642-6 Qualified severance. (a) In general. If a trust...

  10. 12 CFR 1806.201 - Measuring and reporting Qualified Activities.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Measuring and reporting Qualified Activities. 1806.201 Section 1806.201 Banks and Banking COMMUNITY DEVELOPMENT FINANCIAL INSTITUTIONS FUND, DEPARTMENT OF THE TREASURY BANK ENTERPRISE AWARD PROGRAM Awards § 1806.201 Measuring and reporting Qualified Activities. (a) General. An Applicant...

  11. 34 CFR 300.18 - Highly qualified special education teachers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... profession under 34 CFR 200.56(c) which may include a single, high objective uniform State standard of... EDUCATION OF CHILDREN WITH DISABILITIES General Definitions Used in This Part § 300.18 Highly qualified... subjects, the term highly qualified has the meaning given the term in section 9101 of the ESEA and 34...

  12. 34 CFR 300.18 - Highly qualified special education teachers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... profession under 34 CFR 200.56(c) which may include a single, high objective uniform State standard of... EDUCATION OF CHILDREN WITH DISABILITIES General Definitions Used in This Part § 300.18 Highly qualified... subjects, the term highly qualified has the meaning given the term in section 9101 of the ESEA and 34...

  13. What It Means To Be a "Highly Qualified Teacher".

    ERIC Educational Resources Information Center

    Berry, Barnett

    This essay distinguishes between the No Child Left Behind (NCLB) Act's narrow definition of highly qualified teachers and the full range of skills and knowledge teachers must have to teach all children effectively. It asserts that the NCLB's lack of distinction between minimally and highly qualified teachers, along with rapid implementation…

  14. 42 CFR 436.128 - Coverage for certain qualified aliens.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 4 2013-10-01 2013-10-01 false Coverage for certain qualified aliens. 436.128... Mandatory Coverage of the Categorically Needy § 436.128 Coverage for certain qualified aliens. The agency... § 440.255(c) of this chapter to those aliens described in § 436.406(c) of this subpart....

  15. 42 CFR 436.128 - Coverage for certain qualified aliens.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 4 2011-10-01 2011-10-01 false Coverage for certain qualified aliens. 436.128... Mandatory Coverage of the Categorically Needy § 436.128 Coverage for certain qualified aliens. The agency... § 440.255(c) of this chapter to those aliens described in § 436.406(c) of this subpart....

  16. 42 CFR 436.128 - Coverage for certain qualified aliens.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Coverage for certain qualified aliens. 436.128... Mandatory Coverage of the Categorically Needy § 436.128 Coverage for certain qualified aliens. The agency... § 440.255(c) of this chapter to those aliens described in § 436.406(c) of this subpart....

  17. 42 CFR 436.128 - Coverage for certain qualified aliens.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 4 2012-10-01 2012-10-01 false Coverage for certain qualified aliens. 436.128... Mandatory Coverage of the Categorically Needy § 436.128 Coverage for certain qualified aliens. The agency... § 440.255(c) of this chapter to those aliens described in § 436.406(c) of this subpart....

  18. 26 CFR 1.41-2 - Qualified research expenses.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 41(b)(2)(B) means the actual conduct of qualified research (as in the case of a scientist conducting... research scientist who directly supervises laboratory experiments, but who may not actually perform... managers report, even if that manager is a qualified research scientist. (3) Direct support. The...

  19. 26 CFR 1.41-2 - Qualified research expenses.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 41(b)(2)(B) means the actual conduct of qualified research (as in the case of a scientist conducting... research scientist who directly supervises laboratory experiments, but who may not actually perform... managers report, even if that manager is a qualified research scientist. (3) Direct support. The...

  20. 13 CFR 107.130 - Requirement for qualified management.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... qualified management. When applying for a license, you must show, to the satisfaction of SBA, that your current or proposed management is qualified and has the knowledge, experience, and capability necessary... management. 107.130 Section 107.130 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION...

  1. 26 CFR 1.103A-2 - Qualified mortgage bond.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 2 2014-04-01 2014-04-01 false Qualified mortgage bond. 1.103A-2 Section 1.103A-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Items Specifically Excluded from Gross Income § 1.103A-2 Qualified mortgage bond. (a)-(j) (k) Information...

  2. 24 CFR 761.15 - Qualifying for funding.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 4 2013-04-01 2013-04-01 false Qualifying for funding. 761.15... AND PUBLIC AND INDIAN HOUSING PROGRAMS) DRUG ELIMINATION PROGRAMS Grant Funding § 761.15 Qualifying for funding. (a) Qualifications for PHDEP funding—(1) Eligible applicants. The following are...

  3. 24 CFR 761.15 - Qualifying for funding.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 4 2012-04-01 2012-04-01 false Qualifying for funding. 761.15... AND PUBLIC AND INDIAN HOUSING PROGRAMS) DRUG ELIMINATION PROGRAMS Grant Funding § 761.15 Qualifying for funding. (a) Qualifications for PHDEP funding—(1) Eligible applicants. The following are...

  4. 26 CFR 1.127-2 - Qualified educational assistance program.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 2 2012-04-01 2012-04-01 false Qualified educational assistance program. 1.127-2 Section 1.127-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Items Specifically Excluded from Gross Income § 1.127-2 Qualified educational assistance program....

  5. 26 CFR 1.127-2 - Qualified educational assistance program.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 2 2014-04-01 2014-04-01 false Qualified educational assistance program. 1.127-2 Section 1.127-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Items Specifically Excluded from Gross Income § 1.127-2 Qualified educational assistance program....

  6. 49 CFR 192.144 - Qualifying metallic components.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Qualifying metallic components. 192.144 Section....144 Qualifying metallic components. Notwithstanding any requirement of this subpart which incorporates by reference an edition of a document listed in § 192.7 or Appendix B of this part, a...

  7. 43 CFR 3106.7-1 - Failure to qualify.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Failure to qualify. 3106.7-1 Section 3106.7-1 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND..., Sublease or Otherwise § 3106.7-1 Failure to qualify. No transfer of record title or of operating...

  8. 43 CFR 3106.7-1 - Failure to qualify.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Failure to qualify. 3106.7-1 Section 3106.7-1 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND..., Sublease or Otherwise § 3106.7-1 Failure to qualify. No transfer of record title or of operating...

  9. 43 CFR 3106.7-1 - Failure to qualify.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Failure to qualify. 3106.7-1 Section 3106.7-1 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND..., Sublease or Otherwise § 3106.7-1 Failure to qualify. No transfer of record title or of operating...

  10. 7 CFR 701.210 - Qualifying minimum cost of restoration.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 7 2014-01-01 2014-01-01 false Qualifying minimum cost of restoration. 701.210... RESTORATION PROGRAM, AND CERTAIN RELATED PROGRAMS PREVIOUSLY ADMINISTERED UNDER THIS PART Emergency Forest Restoration Program § 701.210 Qualifying minimum cost of restoration. (a) FSA will establish the...

  11. 7 CFR 701.210 - Qualifying minimum cost of restoration.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 7 2011-01-01 2011-01-01 false Qualifying minimum cost of restoration. 701.210... RESTORATION PROGRAM, AND CERTAIN RELATED PROGRAMS PREVIOUSLY ADMINISTERED UNDER THIS PART Emergency Forest Restoration Program § 701.210 Qualifying minimum cost of restoration. (a) FSA will establish the...

  12. 7 CFR 701.210 - Qualifying minimum cost of restoration.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 7 2013-01-01 2013-01-01 false Qualifying minimum cost of restoration. 701.210... RESTORATION PROGRAM, AND CERTAIN RELATED PROGRAMS PREVIOUSLY ADMINISTERED UNDER THIS PART Emergency Forest Restoration Program § 701.210 Qualifying minimum cost of restoration. (a) FSA will establish the...

  13. 7 CFR 701.210 - Qualifying minimum cost of restoration.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 7 2012-01-01 2012-01-01 false Qualifying minimum cost of restoration. 701.210... RESTORATION PROGRAM, AND CERTAIN RELATED PROGRAMS PREVIOUSLY ADMINISTERED UNDER THIS PART Emergency Forest Restoration Program § 701.210 Qualifying minimum cost of restoration. (a) FSA will establish the...

  14. 24 CFR 266.100 - Qualified housing finance agency (HFA).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Qualified housing finance agency... AUTHORITIES HOUSING FINANCE AGENCY RISK-SHARING PROGRAM FOR INSURED AFFORDABLE MULTIFAMILY PROJECT LOANS Housing Finance Agency Requirements § 266.100 Qualified housing finance agency (HFA). (a)...

  15. 24 CFR 266.100 - Qualified housing finance agency (HFA).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Qualified housing finance agency... AUTHORITIES HOUSING FINANCE AGENCY RISK-SHARING PROGRAM FOR INSURED AFFORDABLE MULTIFAMILY PROJECT LOANS Housing Finance Agency Requirements § 266.100 Qualified housing finance agency (HFA). (a)...

  16. 12 CFR 621.4 - Audit by qualified public accountant.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... selects a qualified public accountant to audit its financial statements and provide an opinion thereon for... Section 621.4 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM ACCOUNTING AND REPORTING... annually, have its financial statements audited by a qualified public accountant in accordance...

  17. 45 CFR 1151.12 - Qualified handicapped person.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 45 Public Welfare 3 2010-10-01 2010-10-01 false Qualified handicapped person. 1151.12 Section 1151... AND THE HUMANITIES NATIONAL ENDOWMENT FOR THE ARTS NONDISCRIMINATION ON THE BASIS OF HANDICAP Standards for Determining Who Are Handicapped Persons § 1151.12 Qualified handicapped person....

  18. 26 CFR 1.7704-3 - Qualifying income.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 13 2012-04-01 2012-04-01 false Qualifying income. 1.7704-3 Section 1.7704-3 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) General Actuarial Valuations § 1.7704-3 Qualifying income. (a)...

  19. 26 CFR 1.7704-3 - Qualifying income.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 13 2010-04-01 2010-04-01 false Qualifying income. 1.7704-3 Section 1.7704-3 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES General Actuarial Valuations § 1.7704-3 Qualifying income. (a) Certain investment...

  20. 26 CFR 1.7704-3 - Qualifying income.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 13 2013-04-01 2013-04-01 false Qualifying income. 1.7704-3 Section 1.7704-3 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) General Actuarial Valuations § 1.7704-3 Qualifying income. (a)...

  1. 26 CFR 1.7704-3 - Qualifying income.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 13 2014-04-01 2014-04-01 false Qualifying income. 1.7704-3 Section 1.7704-3 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) General Actuarial Valuations § 1.7704-3 Qualifying income. (a)...

  2. 26 CFR 1.7704-3 - Qualifying income.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 13 2011-04-01 2011-04-01 false Qualifying income. 1.7704-3 Section 1.7704-3 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) General Actuarial Valuations § 1.7704-3 Qualifying income. (a)...

  3. 31 CFR Appendix A to Part 500 - Qualifying International Institutions

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Qualifying International Institutions... Pt. 500, App. A Appendix A to Part 500—Qualifying International Institutions Asian Development Bank (ADB) Food and Agricultural Organization (FAO) International Bank for Reconstruction and...

  4. 26 CFR 1.41-2 - Qualified research expenses.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 41(b)(2)(B) means the actual conduct of qualified research (as in the case of a scientist conducting... research scientist who directly supervises laboratory experiments, but who may not actually perform... managers report, even if that manager is a qualified research scientist. (3) Direct support. The...

  5. 26 CFR 1.41-2 - Qualified research expenses.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 41(b)(2)(B) means the actual conduct of qualified research (as in the case of a scientist conducting... research scientist who directly supervises laboratory experiments, but who may not actually perform... managers report, even if that manager is a qualified research scientist. (3) Direct support. The...

  6. 26 CFR 1.41-2 - Qualified research expenses.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 41(b)(2)(B) means the actual conduct of qualified research (as in the case of a scientist conducting... research scientist who directly supervises laboratory experiments, but who may not actually perform... managers report, even if that manager is a qualified research scientist. (3) Direct support. The...

  7. 42 CFR 436.128 - Coverage for certain qualified aliens.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 4 2014-10-01 2014-10-01 false Coverage for certain qualified aliens. 436.128... Mandatory Coverage of the Categorically Needy § 436.128 Coverage for certain qualified aliens. The agency... § 440.255(c) of this chapter to those aliens described in § 436.406(c) of this subpart....

  8. 38 CFR 21.6521 - Employment of qualified veterans.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Employment of qualified veterans. 21.6521 Section 21.6521 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... Rehabilitation § 21.6521 Employment of qualified veterans. (a) Provisions of the IEAP (Individualized...

  9. 38 CFR 21.6521 - Employment of qualified veterans.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2012-07-01 2012-07-01 false Employment of qualified veterans. 21.6521 Section 21.6521 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... Rehabilitation § 21.6521 Employment of qualified veterans. (a) Provisions of the IEAP (Individualized...

  10. 38 CFR 21.6521 - Employment of qualified veterans.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2014-07-01 2014-07-01 false Employment of qualified veterans. 21.6521 Section 21.6521 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... Rehabilitation § 21.6521 Employment of qualified veterans. (a) Provisions of the IEAP (Individualized...

  11. 38 CFR 21.6521 - Employment of qualified veterans.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2011-07-01 2011-07-01 false Employment of qualified veterans. 21.6521 Section 21.6521 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... Rehabilitation § 21.6521 Employment of qualified veterans. (a) Provisions of the IEAP (Individualized...

  12. 38 CFR 21.6521 - Employment of qualified veterans.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 2 2013-07-01 2013-07-01 false Employment of qualified veterans. 21.6521 Section 21.6521 Pensions, Bonuses, and Veterans' Relief DEPARTMENT OF VETERANS AFFAIRS... Rehabilitation § 21.6521 Employment of qualified veterans. (a) Provisions of the IEAP (Individualized...

  13. 49 CFR 192.283 - Plastic pipe: Qualifying joining procedures.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Plastic pipe: Qualifying joining procedures. 192... Materials Other Than by Welding § 192.283 Plastic pipe: Qualifying joining procedures. (a) Heat fusion... for making plastic pipe joints by a heat fusion, solvent cement, or adhesive method, the...

  14. 49 CFR 192.283 - Plastic pipe: Qualifying joining procedures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Plastic pipe: Qualifying joining procedures. 192... Materials Other Than by Welding § 192.283 Plastic pipe: Qualifying joining procedures. (a) Heat fusion... for making plastic pipe joints by a heat fusion, solvent cement, or adhesive method, the...

  15. 49 CFR 192.283 - Plastic pipe: Qualifying joining procedures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Plastic pipe: Qualifying joining procedures. 192... Materials Other Than by Welding § 192.283 Plastic pipe: Qualifying joining procedures. (a) Heat fusion... for making plastic pipe joints by a heat fusion, solvent cement, or adhesive method, the...

  16. 26 CFR 301.6362-5 - Qualified nonresident tax.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 18 2010-04-01 2010-04-01 false Qualified nonresident tax. 301.6362-5 Section...-5 Qualified nonresident tax. (a) In general. A tax meets the requirements of section 6362(d) and this section only if: (1) The tax is imposed by a State which simultaneously imposes a resident...

  17. What Constitutes a Highly Qualified Physical Education Teacher?

    ERIC Educational Resources Information Center

    American Alliance for Health, Physical Education, Recreation and Dance (NJ1), 2007

    2007-01-01

    It is the position of the National Association for Sport and Physical Education (NASPE) that is it critical to have highly qualified physical education teachers delivering a standards-based curriculum that will assist children in adopting and maintaining healthy lifestyles. NASPE acknowledges that highly qualified physical education teachers will…

  18. What Constitutes a Highly Qualified Physical Education Teacher?

    ERIC Educational Resources Information Center

    Napper-Owen, Gloria E.; Marston, Rip; Van Volkinburg, Pat; Afeman, Helene; Brewer, Joan

    2008-01-01

    The National Association for Sport and Physical Education (NASPE) is an advocate for having highly qualified physical education teachers deliver developmentally appropriate, standards-based instruction in schools. However, a comprehensive definition of what constitutes a highly qualified physical education teacher did not exist until recently.…

  19. 42 CFR 417.412 - Qualifying condition: Administration and management.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 3 2011-10-01 2011-10-01 false Qualifying condition: Administration and management... AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM HEALTH MAINTENANCE ORGANIZATIONS, COMPETITIVE MEDICAL... Qualifying condition: Administration and management. The HMO or CMP must demonstrate that it— (a)...

  20. What Is a Highly Qualified Adapted Physical Education Teacher?

    ERIC Educational Resources Information Center

    Lytle, Rebecca; Lavay, Barry; Rizzo, Terry

    2010-01-01

    This article presents information related to the new position statement on the definition of a "highly qualified adapted physical education teacher" published by the Adapted Physical Activity Council (a council of the American Alliance for Health, Physical Education, Recreation and Dance). It discusses the legal references for "highly qualified"…

  1. 26 CFR 1.110-1 - Qualified lessee construction allowances.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 2 2014-04-01 2014-04-01 false Qualified lessee construction allowances. 1.110-1 Section 1.110-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Items Specifically Excluded from Gross Income § 1.110-1 Qualified lessee construction allowances....

  2. 26 CFR 1.110-1 - Qualified lessee construction allowances.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 2 2013-04-01 2013-04-01 false Qualified lessee construction allowances. 1.110-1 Section 1.110-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Items Specifically Excluded from Gross Income § 1.110-1 Qualified lessee construction allowances....

  3. 26 CFR 1.911-2 - Qualified individuals.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 10 2012-04-01 2012-04-01 false Qualified individuals. 1.911-2 Section 1.911-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Earned Income of Citizens Or Residents of United States § 1.911-2 Qualified individuals. (a) In general. An...

  4. 13 CFR 107.130 - Requirement for qualified management.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 13 Business Credit and Assistance 1 2014-01-01 2014-01-01 false Requirement for qualified management. 107.130 Section 107.130 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS INVESTMENT COMPANIES Qualifying for an SBIC License Organizing An Sbic § 107.130 Requirement...

  5. 13 CFR 107.130 - Requirement for qualified management.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 13 Business Credit and Assistance 1 2012-01-01 2012-01-01 false Requirement for qualified management. 107.130 Section 107.130 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS INVESTMENT COMPANIES Qualifying for an SBIC License Organizing An Sbic § 107.130 Requirement...

  6. 13 CFR 107.130 - Requirement for qualified management.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 13 Business Credit and Assistance 1 2013-01-01 2013-01-01 false Requirement for qualified management. 107.130 Section 107.130 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS INVESTMENT COMPANIES Qualifying for an SBIC License Organizing An Sbic § 107.130 Requirement...

  7. 32 CFR 901.19 - Qualified alternate selection.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Qualified alternate selection. 901.19 Section 901.19 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE MILITARY TRAINING AND SCHOOLS APPOINTMENT TO THE UNITED STATES AIR FORCE ACADEMY Nomination Procedures and Requirements § 901.19 Qualified alternate selection....

  8. 32 CFR 901.19 - Qualified alternate selection.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Qualified alternate selection. 901.19 Section 901.19 National Defense Department of Defense (Continued) DEPARTMENT OF THE AIR FORCE MILITARY TRAINING AND SCHOOLS APPOINTMENT TO THE UNITED STATES AIR FORCE ACADEMY Nomination Procedures and Requirements § 901.19 Qualified alternate selection....

  9. 29 CFR 779.384 - May qualify as exempt establishments.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false May qualify as exempt establishments. 779.384 Section 779... ACT AS APPLIED TO RETAILERS OF GOODS OR SERVICES Exemptions for Certain Retail or Service Establishments Motion Picture Theaters § 779.384 May qualify as exempt establishments. Section 13(a)(9) of...

  10. 29 CFR 779.384 - May qualify as exempt establishments.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Establishments Motion Picture Theaters § 779.384 May qualify as exempt establishments. Section 13(a)(9) of the... employed by an establishment which is a motion picture theater.” This exemption will be applicable... part. A motion picture theater may also qualify as an exempt retail or service establishment...

  11. 29 CFR 779.384 - May qualify as exempt establishments.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Establishments Motion Picture Theaters § 779.384 May qualify as exempt establishments. Section 13(a)(9) of the... employed by an establishment which is a motion picture theater.” This exemption will be applicable... part. A motion picture theater may also qualify as an exempt retail or service establishment...

  12. 29 CFR 779.384 - May qualify as exempt establishments.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Establishments Motion Picture Theaters § 779.384 May qualify as exempt establishments. Section 13(a)(9) of the... employed by an establishment which is a motion picture theater.” This exemption will be applicable... part. A motion picture theater may also qualify as an exempt retail or service establishment...

  13. 13 CFR 107.130 - Requirement for qualified management.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... qualified management. When applying for a license, you must show, to the satisfaction of SBA, that your current or proposed management is qualified and has the knowledge, experience, and capability necessary... management. 107.130 Section 107.130 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION...

  14. 26 CFR 1.405-1 - Qualified bond purchase plans.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 5 2014-04-01 2014-04-01 false Qualified bond purchase plans. 1.405-1 Section 1... bond purchase plans. (a) Introduction. Section 405 relates to the requirements for qualification of... purchased under a qualified bond purchase plan described in section 405(a) and paragraph (b) of this...

  15. 26 CFR 1.405-1 - Qualified bond purchase plans.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 5 2012-04-01 2011-04-01 true Qualified bond purchase plans. 1.405-1 Section 1... bond purchase plans. (a) Introduction. Section 405 relates to the requirements for qualification of... purchased under a qualified bond purchase plan described in section 405(a) and paragraph (b) of this...

  16. 26 CFR 1.405-1 - Qualified bond purchase plans.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 5 2013-04-01 2013-04-01 false Qualified bond purchase plans. 1.405-1 Section 1... bond purchase plans. (a) Introduction. Section 405 relates to the requirements for qualification of... purchased under a qualified bond purchase plan described in section 405(a) and paragraph (b) of this...

  17. 43 CFR 3472.1-1 - Qualified applicants and bidders.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Qualified applicants and bidders. 3472.1-1 Section 3472.1-1 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND... Lease Qualification Requirements § 3472.1-1 Qualified applicants and bidders. A lease may be issued...

  18. 43 CFR 3472.1-1 - Qualified applicants and bidders.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Qualified applicants and bidders. 3472.1-1 Section 3472.1-1 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND... Lease Qualification Requirements § 3472.1-1 Qualified applicants and bidders. A lease may be issued...

  19. 24 CFR 266.100 - Qualified housing finance agency (HFA).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 2 2013-04-01 2013-04-01 false Qualified housing finance agency... AUTHORITIES HOUSING FINANCE AGENCY RISK-SHARING PROGRAM FOR INSURED AFFORDABLE MULTIFAMILY PROJECT LOANS Housing Finance Agency Requirements § 266.100 Qualified housing finance agency (HFA). (a)...

  20. 24 CFR 266.100 - Qualified housing finance agency (HFA).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Qualified housing finance agency... AUTHORITIES HOUSING FINANCE AGENCY RISK-SHARING PROGRAM FOR INSURED AFFORDABLE MULTIFAMILY PROJECT LOANS Housing Finance Agency Requirements § 266.100 Qualified housing finance agency (HFA). (a)...

  1. 24 CFR 266.100 - Qualified housing finance agency (HFA).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false Qualified housing finance agency... AUTHORITIES HOUSING FINANCE AGENCY RISK-SHARING PROGRAM FOR INSURED AFFORDABLE MULTIFAMILY PROJECT LOANS Housing Finance Agency Requirements § 266.100 Qualified housing finance agency (HFA). (a)...

  2. 77 FR 26175 - Section 42 Qualified Contract Provisions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-03

    ... contract provisions under section 42(h)(6)(F) was published in the Federal Register (72 FR 33706). Written... Internal Revenue Service 26 CFR Parts 1 and 602 RIN 1545-BD20 Section 42 Qualified Contract Provisions... housing credit agencies to obtain a qualified contract (as defined in section 42(h)(6)(F) of the...

  3. 7 CFR 1450.101 - Qualified biomass conversion facility.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 10 2012-01-01 2012-01-01 false Qualified biomass conversion facility. 1450.101... CORPORATION, DEPARTMENT OF AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS BIOMASS CROP ASSISTANCE PROGRAM (BCAP) Matching Payments § 1450.101 Qualified biomass conversion facility. (a) To be considered...

  4. 7 CFR 1450.101 - Qualified biomass conversion facility.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 10 2013-01-01 2013-01-01 false Qualified biomass conversion facility. 1450.101... CORPORATION, DEPARTMENT OF AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS BIOMASS CROP ASSISTANCE PROGRAM (BCAP) Matching Payments § 1450.101 Qualified biomass conversion facility. (a) To be considered...

  5. 26 CFR 1.132-3 - Qualified employee discounts.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 2 2012-04-01 2012-04-01 false Qualified employee discounts. 1.132-3 Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Items Specifically Excluded from Gross Income § 1.132-3 Qualified employee discounts. (a) In general—(1) Definition. Gross income does not include the value of a...

  6. 26 CFR 1.1295-1 - Qualified electing funds.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 11 2010-04-01 2010-04-01 true Qualified electing funds. 1.1295-1 Section 1.1295-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES Special Rules for Determining Capital Gains and Losses § 1.1295-1 Qualified...

  7. 26 CFR 1.132-3 - Qualified employee discounts.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 2 2013-04-01 2013-04-01 false Qualified employee discounts. 1.132-3 Section 1... (CONTINUED) INCOME TAXES (CONTINUED) Items Specifically Excluded from Gross Income § 1.132-3 Qualified employee discounts. (a) In general—(1) Definition. Gross income does not include the value of a...

  8. 26 CFR 1.1092(c)-1 - Qualified covered calls.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 11 2012-04-01 2012-04-01 false Qualified covered calls. 1.1092(c)-1 Section 1.1092(c)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Wash Sales of Stock Or Securities § 1.1092(c)-1 Qualified covered...

  9. 26 CFR 52.4682-2 - Qualifying sales.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... as propellants in metered-dose inhalers), ODCs sold in qualifying sales are taxed at a reduced rate... faith. (4) Use as propellants in metered-dose inhalers. A sale of ODCs is a qualifying sale for purposes...) Certificate relating to ODCs used as propellants in metered-dose inhalers—(i) ODCs that will be resold for...

  10. 26 CFR 52.4682-2 - Qualifying sales.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... as propellants in metered-dose inhalers), ODCs sold in qualifying sales are taxed at a reduced rate... faith. (4) Use as propellants in metered-dose inhalers. A sale of ODCs is a qualifying sale for purposes...) Certificate relating to ODCs used as propellants in metered-dose inhalers—(i) ODCs that will be resold for...

  11. 26 CFR 52.4682-2 - Qualifying sales.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... as propellants in metered-dose inhalers), ODCs sold in qualifying sales are taxed at a reduced rate... faith. (4) Use as propellants in metered-dose inhalers. A sale of ODCs is a qualifying sale for purposes...) Certificate relating to ODCs used as propellants in metered-dose inhalers—(i) ODCs that will be resold for...

  12. 26 CFR 52.4682-2 - Qualifying sales.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... as propellants in metered-dose inhalers), ODCs sold in qualifying sales are taxed at a reduced rate... faith. (4) Use as propellants in metered-dose inhalers. A sale of ODCs is a qualifying sale for purposes...) Certificate relating to ODCs used as propellants in metered-dose inhalers—(i) ODCs that will be resold for...

  13. 26 CFR 1.465-27 - Qualified nonrecourse financing.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) Which is not convertible debt. (2) Security for qualified nonrecourse financing—(i) Types of property... 26 Internal Revenue 6 2010-04-01 2010-04-01 false Qualified nonrecourse financing. 1.465-27... financing. (a) In general. Notwithstanding any provision of section 465(b) or the regulations under...

  14. 24 CFR 3286.303 - Responsibilities of qualified trainers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...-Administered States § 3286.303 Responsibilities of qualified trainers. (a) Curriculum and hours. In providing... program, qualified trainers must adequately address the curriculum and instruction-time requirements... compliance with the applicable curriculum and time requirements under subparts C and D of this part....

  15. 20 CFR 617.11 - Qualifying requirements for TRA.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Qualifying requirements for TRA. 617.11 Section 617.11 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR TRADE ADJUSTMENT ASSISTANCE FOR WORKERS UNDER THE TRADE ACT OF 1974 Trade Readjustment Allowances (TRA) § 617.11 Qualifying requirements for TRA. (a)...

  16. Time-dependent response of filamentary composite spherical pressure vessels

    NASA Technical Reports Server (NTRS)

    Dozier, J. D.

    1983-01-01

    A filamentary composite spherical pressure vessel is modeled as a pseudoisotropic (or transversely isotropic) composite shell, with the effects of the liner and fill tubes omitted. Equations of elasticity, macromechanical and micromechanical formulations, and laminate properties are derived for the application of an internally pressured spherical composite vessel. Viscoelastic properties for the composite matrix are used to characterize time-dependent behavior. Using the maximum strain theory of failure, burst pressure and critical strain equations are formulated, solved in the Laplace domain with an associated elastic solution, and inverted back into the time domain using the method of collocation. Viscoelastic properties of HBFR-55 resin are experimentally determined and a Kevlar/HBFR-55 system is evaluated with a FORTRAN program. The computed reduction in burst pressure with respect to time indicates that the analysis employed may be used to predict the time-dependent response of a filamentary composite spherical pressure vessel.

  17. Cybernetica Qualified: Technical vs. Creative Writing.

    ERIC Educational Resources Information Center

    Meis, Ben H.

    1984-01-01

    Discusses the similarities and differences between the kind of writing that is commonly taught in English courses (composition, creative writing) and that taught in technical education classes (technical report writing, technical communications); and between creative and technical writers. (DMM)

  18. 26 CFR 1.401(a)-20 - Requirements of qualified joint and survivor annuity and qualified preretirement survivor annuity.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... annuity and qualified preretirement survivor annuity. 1.401(a)-20 Section 1.401(a)-20 Internal Revenue... Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.401(a)-20 Requirements of qualified joint and... purchase pension plan. A makes an in-service withdrawal of $20,000 attributable to voluntary...

  19. 26 CFR 1.401(a)-20 - Requirements of qualified joint and survivor annuity and qualified preretirement survivor annuity.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... annuity and qualified preretirement survivor annuity. 1.401(a)-20 Section 1.401(a)-20 Internal Revenue... (CONTINUED) Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.401(a)-20 Requirements of qualified joint... purchase pension plan. A makes an in-service withdrawal of $20,000 attributable to voluntary...

  20. 26 CFR 1.401(a)-20 - Requirements of qualified joint and survivor annuity and qualified preretirement survivor annuity.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 5 2013-04-01 2013-04-01 false Requirements of qualified joint and survivor annuity and qualified preretirement survivor annuity. 1.401(a)-20 Section 1.401(a)-20 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME TAX (CONTINUED) INCOME TAXES (CONTINUED) Pension, Profit-Sharing, Stock...

  1. High-performance fiber/epoxy composite pressure vessels

    NASA Technical Reports Server (NTRS)

    Chiao, T. T.; Hamstad, M. A.; Jessop, E. S.; Toland, R. H.

    1978-01-01

    Activities described include: (1) determining the applicability of an ultrahigh-strength graphite fiber to composite pressure vessels; (2) defining the fatigue performance of thin-titanium-lined, high-strength graphite/epoxy pressure vessel; (3) selecting epoxy resin systems suitable for filament winding; (4) studying the fatigue life potential of Kevlar 49/epoxy pressure vessels; and (5) developing polymer liners for composite pressure vessels. Kevlar 49/epoxy and graphite fiber/epoxy pressure vessels, 10.2 cm in diameter, some with aluminum liners and some with alternation layers of rubber and polymer were fabricated. To determine liner performance, vessels were subjected to gas permeation tests, fatigue cycling, and burst tests, measuring composite performance, fatigue life, and leak rates. Both the metal and the rubber/polymer liner performed well. Proportionately larger pressure vessels (20.3 and 38 cm in diameter) were made and subjected to the same tests. In these larger vessels, line leakage problems with both liners developed the causes of the leaks were identified and some solutions to such liner problems are recommended.

  2. Energy loss partitioning during ballistic impact of polymer composites

    NASA Technical Reports Server (NTRS)

    Zee, Ralph H.; Hsieh, Chung Y.

    1993-01-01

    The objective of this study is to determine the energy dissipation processes in polymer-matrix composites during impact of ballistic projectiles. These processes include heat, fiber deformation and breakage, matrix deformation and fracture, and interfacial delamination. In this study, experimental measurements were made, using specialized specimen designs and test methods, to isolate the energy consumed by each of these processes during impact in the ballistic range. Using these experiments, relationships between material parameters and energy dissipation were examined. Composites with the same matrix but reinforced with Kevlar, PE, and graphite fabric were included in this study. These fibers were selected based on the differences in their intrinsic properties. Matrix cracking was found to be one of the most important energy absorption mechanisms during impact, especially in ductile samples such as Spectra-900 PE and Kevlar-49 reinforced polymer. On the contrary, delamination dominated the energy dissipation in brittle composites such as graphite reinforced materials. The contribution from frictional forces was also investigated and the energy partitioning among the different processes evaluated.

  3. Recent advances in lightweight, filament-wound composite pressure vessel technology

    NASA Technical Reports Server (NTRS)

    Lark, R. F.

    1977-01-01

    A review of recent advances is presented for lightweight, high performance composite pressure vessel technology that covers the areas of design concepts, fabrication procedures, applications, and performance of vessels subjected to single cycle burst and cyclic fatigue loading. Filament wound fiber/epoxy composite vessels were made from S glass, graphite, and Kevlar 49 fibers and were equipped with both structural and nonstructural liners. Pressure vessels structural efficiencies were attained which represented weight savings, using different liners, of 40 to 60 percent over all titanium pressure vessels. Significant findings in each area are summarized.

  4. Vibro-acoustic analysis of composite plates

    NASA Astrophysics Data System (ADS)

    Sarigül, A. S.; Karagözlü, E.

    2014-03-01

    Vibro-acoustic analysis plays a vital role on the design of aircrafts, spacecrafts, land vehicles and ships produced from thin plates backed by closed cavities, with regard to human health and living comfort. For this type of structures, it is required a coupled solution that takes into account structural-acoustic interaction which is crucial for sensitive solutions. In this study, coupled vibro-acoustic analyses of plates produced from composite materials have been performed by using finite element analysis software. The study has been carried out for E-glass/Epoxy, Kevlar/Epoxy and Carbon/Epoxy plates with different ply angles and numbers of ply. The effects of composite material, ply orientation and number of layer on coupled vibro-acoustic characteristics of plates have been analysed for various combinations. The analysis results have been statistically examined and assessed.

  5. 26 CFR 1.179A-1 - Recapture of deduction for qualified clean-fuel vehicle property and qualified clean-fuel vehicle...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... vehicle property and qualified clean-fuel vehicle refueling property. 1.179A-1 Section 1.179A-1 Internal... of deduction for qualified clean-fuel vehicle property and qualified clean-fuel vehicle refueling property. (a) In general. If a recapture event occurs with respect to a taxpayer's qualified...

  6. 26 CFR 1.179A-1 - Recapture of deduction for qualified clean-fuel vehicle property and qualified clean-fuel vehicle...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... vehicle property and qualified clean-fuel vehicle refueling property. 1.179A-1 Section 1.179A-1 Internal... of deduction for qualified clean-fuel vehicle property and qualified clean-fuel vehicle refueling property. (a) In general. If a recapture event occurs with respect to a taxpayer's qualified...

  7. 26 CFR 1.179A-1 - Recapture of deduction for qualified clean-fuel vehicle property and qualified clean-fuel vehicle...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... vehicle property and qualified clean-fuel vehicle refueling property. 1.179A-1 Section 1.179A-1 Internal... of deduction for qualified clean-fuel vehicle property and qualified clean-fuel vehicle refueling property. (a) In general. If a recapture event occurs with respect to a taxpayer's qualified...

  8. Lightweight composite reflector panels

    NASA Technical Reports Server (NTRS)

    Freeland, R. E.; Mcelroy, P. M.

    1988-01-01

    The Hexel Corp. has produced additional composite panels, based on JPL designs, that: (1) have increased the panel size from 0.15 to 0.40 meters, (2) have improved the as-manufactured surface precision 3.0 to approx. 1.0 micron RMS, (3) have utilized different numbers of face sheet plys, (4) have improved face sheet fiber orientation, (5) have variations of aluminum honeycomb core cell size, (6) have combined graphite/epoxy (Gr/Ep) face sheets with E-glass honeycomb cores, and (7) have used standard aluminum core with face sheets composed of combinations of glass, Kevlar, and carbon fibers. Additionally, JPL has identified candidate alternate materials for the facesheets and core, modified the baseline polymer panel matrix material, and developed new concepts for panel composite cores. Dornier designed and fabricated three 0.6 meter Gr/Ep panels, that were evaluated by JPL. Results of both the Hexel and Dornier panel work were used to characterize the state-of-the-art for Gr/Ep mirrors.

  9. Etude de l'effet du vieillissement sur les proprietes d'un tissu en melange KevlarRTM-PBI utilise dans le revetement exterieur des habits de protection contre le feu

    NASA Astrophysics Data System (ADS)

    Arrieta, Carlos

    The aim of this work is to study and model the effect of three aging factors, temperature, humidity and light radiation, on the properties of a fabric made of a blend of KevlarRTM and PBI fibers frequently used to manufacture fire-protective garments. Accelarated-aging treatments carried out at carefully chosen conditions for the three factors resulted in a sizeable loss of mechanical performance. The breaking force of both the fabric and the yarns extracted from it decreases to less than 50% after one month of continuous exposure. X-ray diffraction (XRD) tests performed on thermally-aged samples indicated an increase of the crystallinity of the fabric, whereas the disappearance of Raman spectral lines suggested instead a reduction of the crystallinity following thermal aging. To explain these seemingly contradictory results, a hypothesis was introduced, stating that two different processes occurred simultaneously during thermal aging. The first one, an increase of size of the crystallites in the direction of the fibers' axis, accounted for the increase in crystallinity observed in XRD tests. The second one, an increase in the gap separating lamellar crystallites that causes a non-measurable reduction of the crystallinity of the sample, was highlighted by the Raman analyses. The results of the dielectric spectroscopy analyses carried out on thermally-aged samples confirmed the XRD results showing a significant change in the Kevlar's morphology during thermal aging. Despite the important decrease of the breaking force that ensued thermal aging, no evidence of a chemical structure modification of KevlarRTM was found. On the other hand, differential thermal analyses conducted on thermally aged fabric samples indicated a reduction of the glass transition temperature of the other component of the blend, namely the PBI, a fact that suggests a decrease of molecular weight after thermal aging. Infrared spectroscopy analyses performed on samples exposed to high humidity

  10. Composite pressure vessels for the Space Shuttle Orbiter

    NASA Technical Reports Server (NTRS)

    Ecord, G. M.

    1977-01-01

    During the development of the Space Shuttle Orbiter propulsion and environmental control subsystems it was recognized that use of composite pressure vessels with load sharing liners could provide significant weight savings for high pressure gas containment. A program is described which was undertaken to assess the utility for orbiter applications of titanium 6Al-4V and Inconel 718 liners overwrapped with Kevlar fibers. Vessel characteristics, design features and test results are presented along with brief descriptions of processes and nondestructive evaluation techniques. The resolutions of anomalies and development of design are also presented. Fracture control as applied to the orbiter composite vessels is briefly discussed. Five of the seven titanium lined vessels in the program experienced premature cyclic failures. These failures were shown to be primarily due to metallurgical anomalies rather than an inherent composite design problem. A nonfragmentary leakage mode of failure was demonstrated at operating pressures. The composite designs will be approximately 25 percent lighter than their all metal counterparts.

  11. Supporting qualified database for uncertainty evaluation

    SciTech Connect

    Petruzzi, A.; Fiori, F.; Kovtonyuk, A.; D'Auria, F.

    2012-07-01

    Uncertainty evaluation constitutes a key feature of BEPU (Best Estimate Plus Uncertainty) process. The uncertainty can be the result of a Monte Carlo type analysis involving input uncertainty parameters or the outcome of a process involving the use of experimental data and connected code calculations. Those uncertainty methods are discussed in several papers and guidelines (IAEA-SRS-52, OECD/NEA BEMUSE reports). The present paper aims at discussing the role and the depth of the analysis required for merging from one side suitable experimental data and on the other side qualified code calculation results. This aspect is mostly connected with the second approach for uncertainty mentioned above, but it can be used also in the framework of the first approach. Namely, the paper discusses the features and structure of the database that includes the following kinds of documents: 1. The' RDS-facility' (Reference Data Set for the selected facility): this includes the description of the facility, the geometrical characterization of any component of the facility, the instrumentations, the data acquisition system, the evaluation of pressure losses, the physical properties of the material and the characterization of pumps, valves and heat losses; 2. The 'RDS-test' (Reference Data Set for the selected test of the facility): this includes the description of the main phenomena investigated during the test, the configuration of the facility for the selected test (possible new evaluation of pressure and heat losses if needed) and the specific boundary and initial conditions; 3. The 'QR' (Qualification Report) of the code calculation results: this includes the description of the nodalization developed following a set of homogeneous techniques, the achievement of the steady state conditions and the qualitative and quantitative analysis of the transient with the characterization of the Relevant Thermal-Hydraulics Aspects (RTA); 4. The EH (Engineering Handbook) of the input nodalization

  12. 49 CFR 109.11 - Assistance of properly qualified personnel.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS AND OIL TRANSPORTATION... this part if the agent is not properly qualified to perform a function that is essential to the...

  13. 49 CFR 109.11 - Assistance of properly qualified personnel.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS AND OIL TRANSPORTATION... this part if the agent is not properly qualified to perform a function that is essential to the...

  14. 49 CFR 109.11 - Assistance of properly qualified personnel.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS AND OIL TRANSPORTATION... conducted under this part if the agent is not properly qualified to perform a function that is essential...

  15. 49 CFR 192.283 - Plastic pipe: Qualifying joining procedures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Materials Other Than by Welding § 192.283 Plastic pipe: Qualifying joining procedures. (a) Heat fusion... for making plastic pipe joints by a heat fusion, solvent cement, or adhesive method, the...

  16. 49 CFR 192.283 - Plastic pipe: Qualifying joining procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Materials Other Than by Welding § 192.283 Plastic pipe: Qualifying joining procedures. (a) Heat fusion... for making plastic pipe joints by a heat fusion, solvent cement, or adhesive method, the...

  17. 26 CFR 1.42-18 - Qualified contracts.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... the owner certain administrative fees for the performance of services in obtaining a qualified... sale to the general public, the Agency may round up the offering price to the next highest multiple...

  18. Differences in moral judgment between nursing students and qualified nurses.

    PubMed

    Kim, Yong-Soon; Park, Jin-Hee; Han, Sung-Suk

    2007-05-01

    This longitudinal study examined how nursing students' moral judgment changes after they become qualified nurses working in a hospital environment. The sample used was a group of 80 nursing students attending a university in Suwon, Korea, between 2001 and 2003. By using a Korean version of the Judgment About Nursing Decisions questionnaire, an instrument used in nursing care research, moral judgment scores based on Ketefian's six nursing dilemmas were determined. The results were as follows: (1) the qualified nurses had significantly higher idealistic moral judgment scores than the nursing students; (2) the qualified nurses showed significantly higher realistic moral judgment scores than the nursing students; and (3) when comparing idealistic and realistic moral judgment scores, both the qualified nurses and the nursing students had higher scores for idealistic moral judgment. Further study is recommended to examine changes in moral judgment. PMID:17459815

  19. 27 CFR 27.134 - Proprietors of qualified premises.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... BUREAU, DEPARTMENT OF THE TREASURY LIQUORS IMPORTATION OF DISTILLED SPIRITS, WINES, AND BEER Importer's Records and Reports Record and Report of Imported Liquors § 27.134 Proprietors of qualified...

  20. Composite Overwrap Pressure Vessels: Mechanics and Stress Rupture Lifting Philosophy

    NASA Technical Reports Server (NTRS)

    Thesken, John C.; Murthy, Pappu L. N.; Phoenix, S. L.

    2009-01-01

    The NASA Engineering and Safety Center (NESC) has been conducting an independent technical assessment to address safety concerns related to the known stress rupture failure mode of filament wound pressure vessels in use on Shuttle and the International Space Station. The Shuttle s Kevlar-49 (DuPont) fiber overwrapped tanks are of particular concern due to their long usage and the poorly understood stress rupture process in Kevlar-49 filaments. Existing long term data show that the rupture process is a function of stress, temperature and time. However due to the presence of load sharing liners and the complex manufacturing procedures, the state of actual fiber stress in flight hardware and test articles is not clearly known. Indeed nonconservative life predictions have been made where stress rupture data and lifing procedures have ignored the contribution of the liner in favor of applied pressure as the controlling load parameter. With the aid of analytical and finite element results, this paper examines the fundamental mechanical response of composite overwrapped pressure vessels including the influence of elastic plastic liners and degraded/creeping overwrap properties. Graphical methods are presented describing the non-linear relationship of applied pressure to Kevlar-49 fiber stress/strain during manufacturing, operations and burst loadings. These are applied to experimental measurements made on a variety of vessel systems to demonstrate the correct calibration of fiber stress as a function of pressure. Applying this analysis to the actual qualification burst data for Shuttle flight hardware revealed that the nominal fiber stress at burst was in some cases 23 percent lower than what had previously been used to predict stress rupture life. These results motivate a detailed discussion of the appropriate stress rupture lifing philosophy for COPVs including the correct transference of stress rupture life data between dissimilar vessels and test articles.

  1. Composite Overwrap Pressure Vessels: Mechanics and Stress Rupture Lifing Philosophy

    NASA Technical Reports Server (NTRS)

    Thesken, John C.; Murthy, Pappu L. N.; Phoenix, Leigh

    2007-01-01

    The NASA Engineering and Safety Center (NESC) has been conducting an independent technical assessment to address safety concerns related to the known stress rupture failure mode of filament wound pressure vessels in use on Shuttle and the International Space Station. The Shuttle's Kevlar-49 fiber overwrapped tanks are of particular concern due to their long usage and the poorly understood stress rupture process in Kevlar-49 filaments. Existing long term data show that the rupture process is a function of stress, temperature and time. However due to the presence of load sharing liners and the complex manufacturing procedures, the state of actual fiber stress in flight hardware and test articles is not clearly known. Indeed non-conservative life predictions have been made where stress rupture data and lifing procedures have ignored the contribution of the liner in favor of applied pressure as the controlling load parameter. With the aid of analytical and finite element results, this paper examines the fundamental mechanical response of composite overwrapped pressure vessels including the influence of elastic-plastic liners and degraded/creeping overwrap properties. Graphical methods are presented describing the non-linear relationship of applied pressure to Kevlar-49 fiber stress/strain during manufacturing, operations and burst loadings. These are applied to experimental measurements made on a variety of vessel systems to demonstrate the correct calibration of fiber stress as a function of pressure. Applying this analysis to the actual qualification burst data for Shuttle flight hardware revealed that the nominal fiber stress at burst was in some cases 23% lower than what had previously been used to predict stress rupture life. These results motivate a detailed discussion of the appropriate stress rupture lifing philosophy for COPVs including the correct transference of stress rupture life data between dissimilar vessels and test articles.

  2. 22 CFR 19.6-2 - Qualifying court order.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Qualifying court order. 19.6-2 Section 19.6-2 Foreign Relations DEPARTMENT OF STATE PERSONNEL BENEFITS FOR SPOUSES AND FORMER SPOUSES OF PARTICIPANTS IN THE FOREIGN SERVICE RETIREMENT AND DISABILITY SYSTEM § 19.6-2 Qualifying court order. (a) To be valid for purposes of this section, a...

  3. Flight Qualified Micro Sun Sensor for Mars Applications

    NASA Technical Reports Server (NTRS)

    Mobasser, Sohrab; Liebe, Carl Christian; Naegle, James; Lee, Choonsup

    2005-01-01

    A Right qualified micro sun sensor is being developed and flight qualified for future Man missions. The micro sun sensor, which Is basically a small pinhole camera, consists of a small mask with pinholes, placed on top of an image detector. Images of the sun are formed on the image detector when the sun illuminates the mask. Image processing is performed in the sun sensor that outputs sun centroids.

  4. Mechanics of composite materials: Recent advances; Proceedings of the Symposium, Virginia Polytechnic Institute and State University, Blacksburg, VA, August 16-19, 1982

    NASA Technical Reports Server (NTRS)

    Hashin, Z. (Editor); Herakovich, C. T. (Editor)

    1983-01-01

    The present conference on the mechanics of composites discusses microstructure's influence on particulate and short fiber composites' thermoelastic and transport properties, the elastoplastic deformation of composites, constitutive equations for viscoplastic composites, the plasticity and fatigue of metal matrix composites, laminate damping mechanisms, the micromechanical modeling of Kevlar/epoxy composites' time-dependent failure, the variational characterization of waves in composites, and computational methods for eigenvalue problems in composite design. Also discussed are the elastic response of laminates, elastic coupling nonlinear effects in unsymmetrical laminates, elasticity solutions for laminate problems having stress singularities, the mechanics of bimodular composite structures, the optimization of laminated plates and shells, NDE for laminates, the role of matrix cracking in the continuum constitutive behavior of a damaged composite ply, and the energy release rates of various microcracks in short fiber composites.

  5. 24 CFR 200.190 - HUD list of qualified 203(k) consultants.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 2 2013-04-01 2013-04-01 false HUD list of qualified 203(k... Participation in FHA Programs Section 203(k) Rehabilitation Loan Consultants § 200.190 HUD list of qualified 203(k) consultants. (a) Qualified consultant list. HUD maintains a list of qualified consultants for...

  6. 24 CFR 200.190 - HUD list of qualified 203(k) consultants.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false HUD list of qualified 203(k... Participation in FHA Programs Section 203(k) Rehabilitation Loan Consultants § 200.190 HUD list of qualified 203(k) consultants. (a) Qualified consultant list. HUD maintains a list of qualified consultants for...

  7. 24 CFR 200.190 - HUD list of qualified 203(k) consultants.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false HUD list of qualified 203(k... Participation in FHA Programs Section 203(k) Rehabilitation Loan Consultants § 200.190 HUD list of qualified 203(k) consultants. (a) Qualified consultant list. HUD maintains a list of qualified consultants for...

  8. 24 CFR 200.190 - HUD list of qualified 203(k) consultants.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false HUD list of qualified 203(k... Participation in FHA Programs Section 203(k) Rehabilitation Loan Consultants § 200.190 HUD list of qualified 203(k) consultants. (a) Qualified consultant list. HUD maintains a list of qualified consultants for...

  9. 26 CFR 48.4041-19 - Exemption for qualified methanol and ethanol fuel.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 16 2010-04-01 2010-04-01 true Exemption for qualified methanol and ethanol....4041-19 Exemption for qualified methanol and ethanol fuel. (a) In general. Under section 4041(b)(2... or use of qualified methanol or ethanol fuel. (b) Qualified methanol or ethanol fuel defined....

  10. 26 CFR 48.4041-19 - Exemption for qualified methanol and ethanol fuel.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 16 2013-04-01 2013-04-01 false Exemption for qualified methanol and ethanol....4041-19 Exemption for qualified methanol and ethanol fuel. (a) In general. Under section 4041(b)(2... or use of qualified methanol or ethanol fuel. (b) Qualified methanol or ethanol fuel defined....

  11. 26 CFR 48.4041-19 - Exemption for qualified methanol and ethanol fuel.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 16 2012-04-01 2012-04-01 false Exemption for qualified methanol and ethanol....4041-19 Exemption for qualified methanol and ethanol fuel. (a) In general. Under section 4041(b)(2... or use of qualified methanol or ethanol fuel. (b) Qualified methanol or ethanol fuel defined....

  12. 26 CFR 48.4041-19 - Exemption for qualified methanol and ethanol fuel.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 16 2011-04-01 2011-04-01 false Exemption for qualified methanol and ethanol....4041-19 Exemption for qualified methanol and ethanol fuel. (a) In general. Under section 4041(b)(2... or use of qualified methanol or ethanol fuel. (b) Qualified methanol or ethanol fuel defined....

  13. 47 CFR 73.1940 - Legally qualified candidates for public office.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... rules in 47 CFR chapter I, be considered legally qualified candidates only in those States or... 47 Telecommunication 4 2010-10-01 2010-10-01 false Legally qualified candidates for public office... qualified candidates for public office. (a) A legally qualified candidate for public office is any...

  14. 26 CFR 1.43-4 - Qualified enhanced oil recovery costs.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 1 2013-04-01 2013-04-01 false Qualified enhanced oil recovery costs. 1.43-4... TAXES Credits Against Tax § 1.43-4 Qualified enhanced oil recovery costs. (a) Qualifying costs—(1) In... “qualified enhanced oil recovery costs” if the amounts are paid or incurred with respect to an asset which...

  15. 26 CFR 1.43-4 - Qualified enhanced oil recovery costs.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 1 2012-04-01 2012-04-01 false Qualified enhanced oil recovery costs. 1.43-4... TAXES Credits Against Tax § 1.43-4 Qualified enhanced oil recovery costs. (a) Qualifying costs—(1) In... “qualified enhanced oil recovery costs” if the amounts are paid or incurred with respect to an asset which...

  16. 26 CFR 1.43-4 - Qualified enhanced oil recovery costs.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 1 2014-04-01 2013-04-01 true Qualified enhanced oil recovery costs. 1.43-4... TAXES Credits Against Tax § 1.43-4 Qualified enhanced oil recovery costs. (a) Qualifying costs—(1) In... “qualified enhanced oil recovery costs” if the amounts are paid or incurred with respect to an asset which...

  17. 26 CFR 1.43-2 - Qualified enhanced oil recovery project.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 1 2013-04-01 2013-04-01 false Qualified enhanced oil recovery project. 1.43-2 Section 1.43-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY INCOME TAX INCOME TAXES Credits Against Tax § 1.43-2 Qualified enhanced oil recovery project. (a) Qualified enhanced oil recovery project. A “qualified enhanced...

  18. 26 CFR 6a.103A-3 - Qualified veterans' mortgage bonds.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 14 2014-04-01 2013-04-01 true Qualified veterans' mortgage bonds. 6a.103A-3....103A-3 Qualified veterans' mortgage bonds. (a) In general. A qualified veterans' mortgage bond shall... taxation. (b) Qualified veterans' mortgage bond. (1) With respect to obligations issued prior to July...

  19. 26 CFR 6a.103A-3 - Qualified veterans' mortgage bonds.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 14 2013-04-01 2013-04-01 false Qualified veterans' mortgage bonds. 6a.103A-3....103A-3 Qualified veterans' mortgage bonds. (a) In general. A qualified veterans' mortgage bond shall... taxation. (b) Qualified veterans' mortgage bond. (1) With respect to obligations issued prior to July...

  20. 26 CFR 6a.103A-3 - Qualified veterans' mortgage bonds.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 14 2012-04-01 2012-04-01 false Qualified veterans' mortgage bonds. 6a.103A-3....103A-3 Qualified veterans' mortgage bonds. (a) In general. A qualified veterans' mortgage bond shall... taxation. (b) Qualified veterans' mortgage bond. (1) With respect to obligations issued prior to July...

  1. 26 CFR 1.42-6 - Buildings qualifying for carryover allocations.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 1 2013-04-01 2013-04-01 false Buildings qualifying for carryover allocations... TAX INCOME TAXES Credits Against Tax § 1.42-6 Buildings qualifying for carryover allocations. (a... carryover allocation may only be made with respect to a qualified building. A qualified building is...

  2. 26 CFR 1.42-6 - Buildings qualifying for carryover allocations.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 1 2014-04-01 2013-04-01 true Buildings qualifying for carryover allocations. 1... INCOME TAXES Credits Against Tax § 1.42-6 Buildings qualifying for carryover allocations. (a) Carryover... carryover allocation may only be made with respect to a qualified building. A qualified building is...

  3. 26 CFR 1.42-6 - Buildings qualifying for carryover allocations.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 1 2012-04-01 2012-04-01 false Buildings qualifying for carryover allocations... TAX INCOME TAXES Credits Against Tax § 1.42-6 Buildings qualifying for carryover allocations. (a... carryover allocation may only be made with respect to a qualified building. A qualified building is...

  4. 24 CFR 200.190 - HUD list of qualified 203(k) consultants.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false HUD list of qualified 203(k... Participation in FHA Programs Section 203(k) Rehabilitation Loan Consultants § 200.190 HUD list of qualified 203(k) consultants. (a) Qualified consultant list. HUD maintains a list of qualified consultants for...

  5. Evaluation of energy absorption of new concepts of aircraft composite subfloor intersections

    NASA Technical Reports Server (NTRS)

    Jones, Lisa E.; Carden, Huey D.

    1989-01-01

    Forty-one composite aircraft subfloor intersection specimens were tested to determine the effects of geometry and material on the energy absorbing behavior, failure characteristics, and post-crush structural integrity of the specimens. The intersections were constructed of twelve ply + or - 45 sub 6 laminates of either Kevlar 49/934 or AS-4/934 graphite-epoxy in heights of 4, 8, and 12 inches. The geometry of the specimens varied in the designs of the intersection attachment angle. Four different geometries were tested.

  6. 30 CFR 203.43 - To which production do I apply the RSV earned from qualified deep wells or qualified phase 1...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... production occurring on and after the later of: (i) May 3, 2004, for an RSV earned by a qualified deep well... interval the top of which is 16,600 feet TVD SS, which becomes a qualified deep well when production begins... production in August 2009, it would not be a qualified deep well because it started production...

  7. Effects of temperature and humidity cycling on the strengths of textile reinforced carbon/epoxy composite materials

    NASA Technical Reports Server (NTRS)

    Cano, Roberto J.; Furrow, Keith W.

    1993-01-01

    Results are presented from an experimental evaluation of the combined effects of temperature and humidity cycling on AS4/3501-6 composites (unstitched, Kevlar 29 stitched, and S-2 glass stitched uniweave fabric) and AS4/E905L composites (2-D, S-2 glass stitched 2-D, and 3-D braided fabric). The AS4/3501-6 uniweave material had a quasi-isotropic layup, whereas the AS4/E905L materials were braided in a (+/-30 deg/0 deg)(sub s) orientation. Data presented include compression strengths and compression-compression fatigue results for uncycled composites and cycled composites (160, 480, 720, and 1280 cycles from 140 deg F at 95 percent relative humidity to -67 deg F). To observe the presence of microcracking within the laminates, photomicrographs were taken of each material type at the end of each cycling period. Microcracks were found to be more prevalent within stitched laminates, predominantly around individual stitches. The glass stitched laminates showed significant microcracking even before cycling. Less microcracking was evident in the Kevlar stitched materials, whereas the unstitched uniweave material developed microcracks only after cycling. The 3-D braid did not develop microcracks. The static compression strengths of the unstitched and Kevlar stitched uniweave materials were degraded by about 10 percent after 1280 temperature/humidity cycles, whereas the reduction in compression strength for the glass stitched uniweave was less than 3 percent. The reduction in compression strength for the glass stitched 2-D braid was less than 8 percent. The unstitched 2-D and 3-D braids did not lose strength from temperature/humidity cycling. The compression-compression fatigue properties of all six material types were not affected by temperature/humidity cycling.

  8. Development of lightweight filament-wound composite vessels

    SciTech Connect

    Kulkarni, S.V.; Chambers, D.I.; Caley, L.E.

    1982-05-01

    Work is reported in the area of design, fabrication, testing and evaluation of various high performance composite pressure vessels with elastomeric and metallic liners. The thrust of this effort was to develop a high performance, fatigue resistant, potentially low-cost ultra-thin titanium-lined high-strength graphite/epoxy spherical pressure vessel for space shuttle applications; and to fabricate Kevlar-49/epoxy elastomeric lined cylindrical pressure vessels with both rigid and flexibilized epoxy resins. With regard to the ultra-thin Ti liner development, it became apparent that the effort required to develop a fabrication process which will meet both the performance and cost requirements was beyond the scope of this program. Consequently, this effort was stopped. However, the potential for developing ultra-thin Ti liners at a reasonably low cost still exists and should be pursued. From the limited number of burst tests that were conducted for the Kevlar-49/epoxy elastomer-lined cylindrical vessels it is evident that both the damage growth process and the failure modes are different for rigid and flexibilized epoxy resin systems. The effect on the performance cannot be, however, conclusively determined at this time. Further testing of these vessels at NASA LeRC may throw some more light on this issue.

  9. Processing and manufacturing of composite materials; Proceedings of the Symposium, 112th ASME Winter Annual Meeting, Atlanta, GA, Dec. 1-6, 1991

    NASA Astrophysics Data System (ADS)

    Srivatsan, T. S.; Chandrashekhar, S.

    Papers are presented on the machining of fiber reinforced composites, the milling of continuous carbon fiber-reinforced epoxy, advances in composite machining with abrasive water jets, delamination in surface plies of graphite/epoxy caused by the edge-trimming process, and cryogenic machining of Kevlar composites. Consideration is given to a thermodynamic evaluation of ceramic-composite cutting tools for machining titanium, microstructural changes in carbon fibers during high-temperature processing, synthesis of particulate-reinforced metal matrix composites using spray techniques, and on-line monitoring of composite prepreg fabrication. Attention is also given to the effects of postannealing on fatigue behavior in PEEK and its short fiber-reinforced composites, the effect of fabrication parameters on void content for filament-wound composites, and the fabrication of a W-1 percent ThO2-reinforced Fe-25Cr-8Al-0.5Y superalloy matrix composite.

  10. 17 CFR 240.3b-8 - Definitions of “Qualified OTC Market Maker, Qualified Third Market Maker” and “Qualified Block...

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... “Qualified Block Positioner”. For the purposes of Regulation U under the Act (12 CFR part 221): (a) The term... Security” (as that term is defined in section 2(j) of Regulation U (12 CFR 221.2(j)) who (1) is a broker or... 15c3-1 (17 CFR 240.15c3-1), (3) has and maintains minimum net capital, as defined in Rule 15c3-1,...

  11. 17 CFR 240.3b-8 - Definitions of “Qualified OTC Market Maker, Qualified Third Market Maker” and “Qualified Block...

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... “Qualified Block Positioner”. For the purposes of Regulation U under the Act (12 CFR part 221): (a) The term... Security” (as that term is defined in section 2(j) of Regulation U (12 CFR 221.2(j)) who (1) is a broker or... 15c3-1 (17 CFR 240.15c3-1), (3) has and maintains minimum net capital, as defined in Rule 15c3-1,...

  12. 17 CFR 240.3b-8 - Definitions of “Qualified OTC Market Maker, Qualified Third Market Maker” and “Qualified Block...

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... “Qualified Block Positioner”. For the purposes of Regulation U under the Act (12 CFR part 221): (a) The term... Security” (as that term is defined in section 2(j) of Regulation U (12 CFR 221.2(j)) who (1) is a broker or... 15c3-1 (17 CFR 240.15c3-1), (3) has and maintains minimum net capital, as defined in Rule 15c3-1,...

  13. 17 CFR 240.3b-8 - Definitions of “Qualified OTC Market Maker, Qualified Third Market Maker” and “Qualified Block...

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... “Qualified Block Positioner”. For the purposes of Regulation U under the Act (12 CFR part 221): (a) The term... Security” (as that term is defined in section 2(j) of Regulation U (12 CFR 221.2(j)) who (1) is a broker or... 15c3-1 (17 CFR 240.15c3-1), (3) has and maintains minimum net capital, as defined in Rule 15c3-1,...

  14. 17 CFR 240.3b-8 - Definitions of “Qualified OTC Market Maker, Qualified Third Market Maker” and “Qualified Block...

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... “Qualified Block Positioner”. For the purposes of Regulation U under the Act (12 CFR part 221): (a) The term... Security” (as that term is defined in section 2(j) of Regulation U (12 CFR 221.2(j)) who (1) is a broker or... 15c3-1 (17 CFR 240.15c3-1), (3) has and maintains minimum net capital, as defined in Rule 15c3-1,...

  15. Accident data study of concrete construction companies' similarities and differences between qualified and non-qualified workers in Spain.

    PubMed

    López-Arquillos, Antonio; Rubio-Romero, Juan Carlos; Gibb, Alistair

    2015-01-01

    The aim of this paper is to discuss findings from an analysis of accidents in concrete construction companies in Spain and to compare the accident rates of qualified and non-qualified workers. A total of 125,021 accidents between 2003 and 2008 involving both blue-collar and white-collar workers were analysed, comparing the variables of occupation, age, company staff, length of service, location of the accident, together with the severity of the accidents. Results showed that lack of experience in the first month is more significant in non-qualified workers and experienced supervisors and that head injuries are more likely to lead to fatalities. The most remarkable similarity was that fatal accidents to and from the worksite are a problem common to both groups of workers. PMID:26327149

  16. Mechanical property of tubular composites manufactured from braided-pultrusion process

    SciTech Connect

    Byun, J.H.; Lee, S.K.

    1994-12-31

    In order to realize the potential of composite materials, it is imperative to develop a manufacturing process, to understand the microstructures, and to assess the structural performance of the composite. The braided-pultrusion process, which combines the pultrusion process with the braiding technology, has been developed by utilizing a novel resin impregnation device. The goal of the development is to achieve both cost-effectiveness and performance of the composite. The tubular composites of diameter 5.3 mm have been produced using Kevlar 49 fiber and polyester resin. In order to assess the mechanical performance of the composites, an analytical method for predicting the elastic constants has been developed. The analysis includes the geometric model of a unit cell, coordinate transformation, and averaging of stiffness and compliance constants of the constituent materials. The analytic predictions were compared favorably with experimental results.

  17. Relationship between Air Force Officer Qualifying Test Scores and Success in Air Weapons Controller Training. Interim Report for the Period November 1982-February 1984.

    ERIC Educational Resources Information Center

    Finegold, Lawrence S.; Rogers, Deborah

    This project investigated the relationship between Air Force Officer Qualifying Test (AFOQT) composite scores and student performance in Air Force air weapons controller training. The purpose of this study was to examine the feasibility of using AFOQT scores as one selection criteria for entry to the air weapons controller field. An analysis of…

  18. Impact resistance of composite fan blades

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Results are presented of a program to determine the impact resistance of composite fan blades subjected to foreign object damage (FOD) while operating under conditions simulating a short take-off and landing (STOL) engine at takeoff. The full-scale TF39 first-stage fan blade was chosen as the base design for the demonstration component since its configuration and operating tip speeds are similar to a typical STOL fan blade several composite configurations had already been designed and evaluated under previous programs. The first portion of the program was devoted toward fabricating and testing high impact resistant, aerodynamically acceptable composite blades which utilized only a single material system in any given blade. In order to increase the blade impact capability beyond this point, several mixed material (hybrid) designs were investigated using S-glass and Kevlar as well as boron and graphite fibers. These hybrid composite blades showed a marked improvement in resistance to bird impact over those blades made of a single composite material. The work conducted under this program has demonstrated substantial improvement in composite fan blades with respect to FOD resistance and has indicated that the hybrid design concept, which utilizes different types of fibers in various portions of a fan blade design depending on the particular requirements of the different areas and the characteristics of the different fibers involved, shows a significant improvement over those designs utilizing only one material system.

  19. 45 CFR 156.265 - Enrollment process for qualified individuals.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 1 2013-10-01 2013-10-01 false Enrollment process for qualified individuals. 156.265 Section 156.265 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES REQUIREMENTS RELATING TO HEALTH CARE ACCESS HEALTH INSURANCE ISSUER STANDARDS UNDER THE AFFORDABLE CARE ACT, INCLUDING...

  20. 45 CFR 156.1240 - Enrollment process for qualified individuals.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 45 Public Welfare 1 2013-10-01 2013-10-01 false Enrollment process for qualified individuals. 156.1240 Section 156.1240 Public Welfare DEPARTMENT OF HEALTH AND HUMAN SERVICES REQUIREMENTS RELATING TO HEALTH CARE ACCESS HEALTH INSURANCE ISSUER STANDARDS UNDER THE AFFORDABLE CARE ACT, INCLUDING...