40 CFR 86.1728-99 - Compliance with emission standards.

Code of Federal Regulations, 2012 CFR

2012-07-01

... part to test for irregular data from a durability-data set. If any data point is identified as a... apply both the outlier procedure and averaging to the same data set, the outlier procedure shall be... shall be determined from the exhaust emission results of the durability-data vehicle(s) for each engine...

40 CFR 86.1825-01 - Durability demonstration procedures for refueling emissions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Durability demonstration procedures for refueling emissions. 86.1825-01 Section 86.1825-01 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance...

40 CFR 86.1825-08 - Durability demonstration procedures for refueling emissions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Durability demonstration procedures for refueling emissions. 86.1825-08 Section 86.1825-08 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance...

40 CFR Appendix Xv to Part 86 - Procedure for Determining an Acceptable Exhaust Regeneration Durability-Data Test Schedule for...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Procedure for Determining an Acceptable Exhaust Regeneration Durability-Data Test Schedule for Diesel Cycle Vehicles Equipped With... Schedule for Diesel Cycle Vehicles Equipped With Periodically Regenerating Trap Oxidizer Systems Certifying...

40 CFR 86.1824-01 - Durability demonstration procedures for evaporative emissions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Durability demonstration procedures for evaporative emissions. This section applies to gasoline-, methanol... constituents. (iv) For flexible-fueled, dual-fueled, multi-fueled, ethanol-fueled and methanol-fueled vehicles... obtained under §§ 86.1845-01, 86.1846-01, 86.1847-01 or from other sources shall be used by the...

40 CFR 86.1824-01 - Durability demonstration procedures for evaporative emissions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Durability demonstration procedures for evaporative emissions. This section applies to gasoline-, methanol... constituents. (iv) For flexible-fueled, dual-fueled, multi-fueled, ethanol-fueled and methanol-fueled vehicles... obtained under §§ 86.1845-01, 86.1846-01, 86.1847-01 or from other sources shall be used by the...

40 CFR 86.1825-08 - Durability demonstration procedures for refueling emissions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... specified in § 86.1805, or (ii) At least 75 percent of the full useful life mileage. In which case, the... Durability demonstration procedures for refueling emissions. This section applies to 2008 and later model... emission levels and deterioration in actual use over the full useful life of candidate in-use vehicles of...

Durability of Flexible Ureteroscopes: A Prospective Evaluation of Longevity, the Factors that Affect it, and Damage Mechanisms.

PubMed

Legemate, Jaap D; Kamphuis, Guido M; Freund, Jan Erik; Baard, Joyce; Zanetti, Stefano P; Catellani, Michele; Oussoren, Harry W; de la Rosette, Jean J

2018-03-10

Flexible ureteroscopy is an established treatment modality for evaluating and treating abnormalities in the upper urinary tract. Reusable ureteroscope (USC) durability is a significant concern. To evaluate the durability of the latest generation of digital and fiber optic reusable flexible USCs and the factors affecting it. Six new flexible USCs from Olympus and Karl Storz were included. The primary endpoint for each USC was its first repair. Data on patient and treatment characteristics, accessory device use, ureteroscopy time, image quality, USC handling, disinfection cycles, type of damage, and deflection loss were collected prospectively. Ureteroscopy. USC durability was measured as the total number of uses and ureteroscopy time before repair. USC handling and image quality were scored. After every procedure, maximal ventral and dorsal USC deflection were documented on digital images. A total of 198 procedures were performed. The median number of procedures was 27 (IQR 16-48; 14h) for the six USCs overall, 27 (IQR 20-56; 14h) for the digital USCs, and 24 (range 10-37; 14h) for the fiber optic USCs. Image quality remained high throughout the study for all six USCs. USC handling and the range of deflection remained good under incremental use. Damage to the distal part of the shaft and shaft coating was the most frequent reason for repair, and was related to intraoperative manual forcing. A limitation of this study is its single-center design. The durability of the latest reusable flexible USCs in the current study was limited to 27 uses (14h). Damage to the flexible shaft was the most important limitation to the durability of the USCs evaluated. Prevention of intraoperative manual forcing of flexible USCs maximizes their overall durability. Current flexible ureteroscopes proved to be durable. Shaft vulnerability was the most important limiting factor affecting durability. Copyright © 2018 European Association of Urology. Published by Elsevier B.V. All rights reserved.

Durability Indicators Comparison for SCC and CC in Tropical Coastal Environments.

PubMed

Calado, Carlos; Camões, Aires; Monteiro, Eliana; Helene, Paulo; Barkokébas, Béda

2015-03-27

Self-compacting concrete (SCC) demands more studies of durability at higher temperatures when subjected to more aggressive environments in comparison to the conventional vibrated concrete (CC). This work aims at presenting results of durability indicators of SCC and CC, having the same water/binder relations and constituents. The applied methodologies were electrical resistivity, diffusion of chloride ions and accelerated carbonation experiments, among others, such as microstructure study, scanning electron microscope and microtomography experiments. The tests were performed in a research laboratory and at a construction site of the Pernambuco Arena. The obtained results shows that the SCC presents an average electrical resistivity 11.4% higher than CC; the average chloride ions diffusion was 63.3% of the CC; the average accelerated carbonation penetration was 45.8% of the CC; and the average open porosity was 55.6% of the CC. As the results demonstrated, the SCC can be more durable than CC, which contributes to elucidate the aspects related to its durability and consequent prolonged life cycle.

Durability Indicators Comparison for SCC and CC in Tropical Coastal Environments

PubMed Central

Calado, Carlos; Camões, Aires; Monteiro, Eliana; Helene, Paulo; Barkokébas, Béda

2015-01-01

Self-compacting concrete (SCC) demands more studies of durability at higher temperatures when subjected to more aggressive environments in comparison to the conventional vibrated concrete (CC). This work aims at presenting results of durability indicators of SCC and CC, having the same water/binder relations and constituents. The applied methodologies were electrical resistivity, diffusion of chloride ions and accelerated carbonation experiments, among others, such as microstructure study, scanning electron microscope and microtomography experiments. The tests were performed in a research laboratory and at a construction site of the Pernambuco Arena. The obtained results shows that the SCC presents an average electrical resistivity 11.4% higher than CC; the average chloride ions diffusion was 63.3% of the CC; the average accelerated carbonation penetration was 45.8% of the CC; and the average open porosity was 55.6% of the CC. As the results demonstrated, the SCC can be more durable than CC, which contributes to elucidate the aspects related to its durability and consequent prolonged life cycle. PMID:28788012

Comparison of highway striping materials.

DOT National Transportation Integrated Search

1980-01-01

This study was undertaken to investigate problems relating to the durability of pavement striping materials used by the Department. The research was limited to an evaluation of the durability and retroreflectance characteristics of selected paints, t...

Durability, value, and reliability of selected electric powered wheelchairs.

PubMed

Fass, Megan V; Cooper, Rory A; Fitzgerald, Shirley G; Schmeler, Mark; Boninger, Michael L; Algood, S David; Ammer, William A; Rentschler, Andrew J; Duncan, John

2004-05-01

To compare the durability, value, and reliability of selected electric powered wheelchairs (EPWs), purchased in 1998. Engineering standards tests of quality and performance. A rehabilitation engineering center. Fifteen EPWs: 3 each of the Jazzy, Quickie, Lancer, Arrow, and Chairman models. Not applicable. Wheelchairs were evaluated for durability (lifespan), value (durability, cost), and reliability (rate of repairs) using 2-drum and curb-drop machines in accordance with the standards of the American National Standards Institute and Rehabilitation Engineering and Assistive Technology Society of North America. The 5 brands differed significantly (P

Comparison of highway striping materials : installation report.

DOT National Transportation Integrated Search

1980-01-01

This study has been undertaken to investigate problems relating to the durability of highway striping materials used by the Department The research is limited to an evaluation of the durability and retroreflectance characteristics of selected paints,...

40 CFR 610.51 - Mileage accumulation procedure.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Mileage accumulation procedure. 610.51 Section 610.51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Durability Test Procedures § 610.51...

40 CFR 610.51 - Mileage accumulation procedure.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Mileage accumulation procedure. 610.51 Section 610.51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Durability Test Procedures § 610.51...

40 CFR 610.51 - Mileage accumulation procedure.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Mileage accumulation procedure. 610.51 Section 610.51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Durability Test Procedures § 610.51...

40 CFR 610.51 - Mileage accumulation procedure.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Mileage accumulation procedure. 610.51 Section 610.51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Durability Test Procedures § 610.51...

40 CFR 610.51 - Mileage accumulation procedure.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Mileage accumulation procedure. 610.51 Section 610.51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Durability Test Procedures § 610.51...

40 CFR 86.1823-08 - Durability demonstration procedures for exhaust emissions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... delivers the appropriate exhaust flow, exhaust constituents, and exhaust temperature to the face of the... vehicles. (2) This data set must consist of randomly procured vehicles from actual customer use. The... equivalency factor. (C) The manufacturer must submit an analysis which evaluates whether the durability...

40 CFR 86.1823-08 - Durability demonstration procedures for exhaust emissions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... judgement, a catalyst aging bench that follows the SBC and delivers the appropriate exhaust flow, exhaust... set must consist of randomly procured vehicles from actual customer use. The vehicles selected for... submit an analysis which evaluates whether the durability objective will be achieved for the vehicle...

Life cycle and economic efficiency analysis phase II : durable pavement markings.

DOT National Transportation Integrated Search

2011-04-01

This report details the Phase II analysis of the life cycle and economic efficiency of inlaid tape : and thermoplastic. Waterborne paint was included as a non-durable for comparison purposes : only. In order to find the most economical product for sp...

Correlation of air void parameters obtained by linear traverse with freeze-thaw durability.

DOT National Transportation Integrated Search

1983-01-01

The correlations obtainable from comparisons of the various air void parameters with the freeze-thaw durability of concretes are listed. It is shown that correlations are no better when only small voids are used than when the total void content is us...

40 CFR 610.61 - Engine dynamometer tests.

Code of Federal Regulations, 2010 CFR

2010-07-01

... dynamometer durability test procedures used by research organizations in government, the oil industry, engine... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Engine dynamometer tests. 610.61... ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Special Test Procedures § 610.61 Engine...

40 CFR 610.61 - Engine dynamometer tests.

Code of Federal Regulations, 2013 CFR

2013-07-01

... dynamometer durability test procedures used by research organizations in government, the oil industry, engine... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Engine dynamometer tests. 610.61... ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Special Test Procedures § 610.61 Engine...

40 CFR 610.61 - Engine dynamometer tests.

Code of Federal Regulations, 2012 CFR

2012-07-01

... dynamometer durability test procedures used by research organizations in government, the oil industry, engine... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Engine dynamometer tests. 610.61... ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Special Test Procedures § 610.61 Engine...

40 CFR 610.61 - Engine dynamometer tests.

Code of Federal Regulations, 2011 CFR

2011-07-01

... dynamometer durability test procedures used by research organizations in government, the oil industry, engine... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Engine dynamometer tests. 610.61... ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Special Test Procedures § 610.61 Engine...

40 CFR 610.61 - Engine dynamometer tests.

Code of Federal Regulations, 2014 CFR

2014-07-01

... dynamometer durability test procedures used by research organizations in government, the oil industry, engine... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Engine dynamometer tests. 610.61... ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Special Test Procedures § 610.61 Engine...

Facile preparation of super durable superhydrophobic materials.

PubMed

Wu, Lei; Zhang, Junping; Li, Bucheng; Fan, Ling; Li, Lingxiao; Wang, Aiqin

2014-10-15

The low stability, complicated and expensive fabrication procedures seriously hinder practical applications of superhydrophobic materials. Here we report an extremely simple method for preparing super durable superhydrophobic materials, e.g., textiles and sponges, by dip coating in fluoropolymers (FPs). The morphology, surface chemical composition, mechanical, chemical and environmental stabilities of the superhydrophobic textiles were investigated. The results show how simple the preparation of super durable superhydrophobic textiles can be! The superhydrophobic textiles outperform their natural counterparts and most of the state-of-the-art synthetic superhydrophobic materials in stability. The intensive mechanical abrasion, long time immersion in various liquids and repeated washing have no obvious influence on the superhydrophobicity. Water drops are spherical in shape on the samples and could easily roll off after these harsh stability tests. In addition, this simple dip coating approach is applicable to various synthetic and natural textiles and can be easily scaled up. Furthermore, the results prove that a two-tier roughness is helpful but not essential with regard to the creation of super durable superhydrophobic textiles. The combination of microscale roughness of textiles and materials with very low surface tension is enough to form super durable superhydrophobic textiles. According to the same procedure, superhydrophobic polyurethane sponges can be prepared, which show high oil absorbency, oil/water separation efficiency and stability. Copyright © 2014 Elsevier Inc. All rights reserved.

Activity and Durability of Iridium Nanoparticles in the Oxygen Evolution Reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alia, Shaun M.; Rasimick, Brian; Ngo, Chilan

Unsupported iridium (Ir) nanoparticles, that serve as standard oxygen evolution reaction (OER) catalysts in acidic electrolyzers, were investigated for electrochemical performance and durability in rotating disk electrode (RDE) half-cells. Fixed potential holds and potential cycling were applied to probe the durability of Ir nanoparticles, and performance losses were found to be driven by particle growth (coarsening) at moderate potential (1.4 to 1.6 V) and Ir dissolution at higher potential (>/=1.8 V). Several different commercially available samples were evaluated and standardized conditions for performance comparison are reported. In conclusion, the electrocatalyst RDE results have also been compared to results obtained formore » performance and durability in electrolysis cells.« less

Activity and Durability of Iridium Nanoparticles in the Oxygen Evolution Reaction

DOE PAGES

Alia, Shaun M.; Rasimick, Brian; Ngo, Chilan; ...

2016-07-15

Unsupported iridium (Ir) nanoparticles, that serve as standard oxygen evolution reaction (OER) catalysts in acidic electrolyzers, were investigated for electrochemical performance and durability in rotating disk electrode (RDE) half-cells. Fixed potential holds and potential cycling were applied to probe the durability of Ir nanoparticles, and performance losses were found to be driven by particle growth (coarsening) at moderate potential (1.4 to 1.6 V) and Ir dissolution at higher potential (>/=1.8 V). Several different commercially available samples were evaluated and standardized conditions for performance comparison are reported. In conclusion, the electrocatalyst RDE results have also been compared to results obtained formore » performance and durability in electrolysis cells.« less

Long-term durability of the distal urethral polypropylene sling for the treatment of stress urinary incontinence: minimum 11-year followup.

PubMed

Rogo-Gupta, Lisa; Baxter, Z Chad; Le, Ngoc-Bich; Raz, Shlomo; Rodríguez, Larissa V

2012-11-01

We report on the long-term outcomes of the distal urethral polypropylene sling for stress urinary incontinence in a patient cohort that was closely followed and whose outcomes were reported at 1 and 5 years after surgery. We performed a prospective study of all consecutive patients who underwent a distal urethral polypropylene sling procedure between November 1999 and April 2000. The 1 and 5-year outcomes for this particular patient cohort were previously reported. At the minimum 11-year followup, outcome was determined by patient self-assessment including validated questionnaires. A total of 69 patients were followed prospectively and followup was obtained for 30. Of those lost to followup 10 were deceased and 5 were cognitively impaired. Mean patient age at followup was 73 years (range 40 to 97). More than 11 years after surgery 48% of patients reported no stress urinary incontinence symptoms and 63% were never bothered by stress urinary incontinence. Patients reported a mean overall symptom improvement of 64% compared to 81% at 5 years. Overall 82% of patients met the criteria for treatment success by symptom scores and 80% met the criteria by bother scores. The distal urethral polypropylene sling procedure has excellent long-term durability in the treatment of stress urinary incontinence, in addition to low morbidity and low cost as previously described. Eleven years after the procedure the majority of patients report symptom improvement. Nevertheless, many older patients are unable to participate in followup. When choosing an anti-incontinence procedure, durability should be considered in light of patient age given that the theoretical advantages of long-term durability are limited by cognitive decline and mortality. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Comparison of enamel bond fatigue durability between universal adhesives and two-step self-etch adhesives: Effect of phosphoric acid pre-etching.

PubMed

Suda, Shunichi; Tsujimoto, Akimasa; Barkmeier, Wayne W; Nojiri, Kie; Nagura, Yuko; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

2018-03-30

The effect of phosphoric acid pre-etching on enamel bond fatigue durability of universal adhesives and two-step self-etch adhesives was investigated. Four universal adhesives and three two-step self-etch adhesives were used. The initial shear bond strengths and shear fatigue strengths to enamel with and without phosphoric acid pre-etching using the adhesives were determined. SEM observations were also conducted. Phosphoric acid pre-etching of enamel was found to increase the bond fatigue durability of universal adhesives, but its effect on two-step self-etch adhesives was material-dependent. In addition, some universal adhesives with phosphoric acid pre-etching showed similar bond fatigue durability to the two-step self-etch adhesives, although the bond fatigue durability of universal adhesives in self-etch mode was lower than that of the two-step self-etch adhesives. Phosphoric acid pre-etching enhances enamel bond fatigue durability of universal adhesives, but the effect of phosphoric acid pre-etching on the bond fatigue durability of two-step self-etch adhesives was material-dependent.

Durability Evaluation of the Effects of Hydro-processed Renewable Jet (HRJ) Blended at 50% with Petroleum JP-8 on a Navistar Maxxforce D10 9.3L Engine

DTIC Science & Technology

2012-05-01

Effects of Hydro-processed Renewable Jet (HRJ) blended at 50% with petroleum JP-8 on a Navistar Maxxforce D10 9.3L Engine 5a. CONTRACT NUMBER...report will be used to assess the effect of the HRJP-8 fuel on engine performance and durability as compared to JP-8. This evaluation requires that two...Hour Durability). Modifications to this procedure are primarily increases to the operating temperatures of the engine coolant, combustion air and

Documenting the Durability and Service Life of Pressure-treated Wood

Treesearch

Stan Lebow; Bessie Woodward; Patricia Lebow

2014-01-01

Estimates of service life are increasingly used to compare life cycle costs of building materials. Because of a lack of published data for treated wood, some users assume a relatively low service life for wood in comparison to alternative materials. Such bias against durable wood products may cause alternative materials to appear more economical. This paper discusses...

Sliding durability of candidate seal fiber materials in hydrogen from 25 to 900 C

NASA Technical Reports Server (NTRS)

Dellacorte, Christopher; Steinetz, Bruce M.

1992-01-01

Sliding durability studies of candidate ceramic fibers were conducted in hydrogen to support the high temperature seal development program at NASA LeRC. Pin-on-disk tests were used to measure the friction and durability of a tow or bundle of ceramic fibers in sliding against a superalloy disk. This procedure was used previously to test candidate fibers in an air environment. The fibers based upon mullite (Al2O3-SiO2) chemistry (Nextel 550, 440, and 312) exhibited better durability in hydrogen than in air. HPZ, a complex silicon carboxynitride fiber which showed good durabilty in air, however, showed a significant loss of durability in hot hydrogen. These results are consistent with recent thermodynamic and experimental studies of ceramic compatibility with hydrogen at elevated temperatures. These research results indicate that only oxide fibers display good durability in both air and hydrogen environments. Also, simple, low cost testing in air can provide an adequate data base for initial seal material screening and selection, especially for oxide fiber candidates. The findings of this research provide critical input to the seal design team.

Short- and long-term effects of clinical audits on compliance with procedures in CT scanning.

PubMed

Oliveri, Antonio; Howarth, Nigel; Gevenois, Pierre Alain; Tack, Denis

2016-08-01

To test the hypothesis that quality clinical audits improve compliance with the procedures in computed tomography (CT) scanning. This retrospective study was conducted in two hospitals, based on 6950 examinations and four procedures, focusing on the acquisition length in lumbar spine CT, the default tube current applied in abdominal un-enhanced CT, the tube potential selection for portal phase abdominal CT and the use of a specific "paediatric brain CT" procedure. The first clinical audit reported compliance with these procedures. After presenting the results to the stakeholders, a second audit was conducted to measure the impact of this information on compliance and was repeated the next year. Comparisons of proportions were performed using the Chi-square Pearson test. Depending on the procedure, the compliance rate ranged from 27 to 88 % during the first audit. After presentation of the audit results to the stakeholders, the compliance rate ranged from 68 to 93 % and was significantly improved for all procedures (P ranging from <0.001 to 0.031) in both hospitals and remained unchanged during the third audit (P ranging from 0.114 to 0.999). Quality improvement through repeated compliance audits with CT procedures durably improves this compliance. • Compliance with CT procedures is operator-dependent and not perfect. • Compliance differs between procedures and hospitals, even within a unified department. • Compliance is improved through audits followed by communication to the stakeholders. • This improvement is sustainable over a one-year period.

40 CFR 610.52 - Maintenance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Maintenance. 610.52 Section 610.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Durability Test Procedures § 610.52 Maintenance. (a...

40 CFR 610.52 - Maintenance.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Maintenance. 610.52 Section 610.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Durability Test Procedures § 610.52 Maintenance. (a...

40 CFR 610.52 - Maintenance.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Maintenance. 610.52 Section 610.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Durability Test Procedures § 610.52 Maintenance. (a...

40 CFR 610.52 - Maintenance.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Maintenance. 610.52 Section 610.52 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Durability Test Procedures § 610.52 Maintenance. (a...

Partial-depth repair of jointed PCC pavements : cast-in-place and precast procedures.

DOT National Transportation Integrated Search

1977-01-01

The installation of durable patches on jointed portland cement concrete pavement using several types of cast-in-place concrete, is described. The recommended procedures for pavement preparation and patch installation are given, and additional mainten...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Linard, Joshua; Hall, Steve

9.1 Compliance Summary The Lakeview, Oregon, Uranium Mill Tailings Radiation Control Act (UMTRCA) Title I Disposal Site was inspected September 16 and 17, 2015. Other than some ongoing concern with erosion-control rock riprap degradation, the disposal cell was in good condition. Some minor fence repairs and vegetation removal, and minor erosion repair work along the west site fence is planned. Inspectors identified no other maintenance needs or cause for a follow-up or contingency inspection. Disposal cell riprap is evaluated annually to ensure continued long-term protection of the cell from erosion during a severe precipitation event. Degradation of the rock riprapmore » was first observed at the site in the mid-1990s. Rock gradation monitoring of the riprap on the west side slope has been performed as part of the annual inspection since 1997 to determine the mean diameter (D 50) value. As prescribed by the monitoring procedure, the rock monitoring is routinely conducted at random locations. However, at the U.S. Nuclear Regulatory Commission’s (NRC’s) request, the 2015 rock monitoring approach deviated from the normal procedure by using a pre-established monitoring grid in a subset area of the west side slope. This changed the monitoring approach from random sampling to biased sampling. The D 50 value measured during the 2015 gradation monitoring is 2.39 inches, which falls below the original D 50 design size range of 2.7–3.9 inches for the Type B size side slope riprap. At NRC’s request, rock durability monitoring was added to the gradation monitoring in 2009 to monitor durability by rock type. Results of the 2015 durability monitoring showed that74 percent of the total rock sampled is durability class code A rock with an assigned durability class of “highly durable” or durability class code B “durable” rock, and that over 90 percent of the 3-inch or larger rock is durability class code A or B. The rock durability classifications are further explained in Section 9.4.2.2.« less

Durability and mechanical properties of silane cross-linked wood thermoplastic composites

Treesearch

Magnus Bengtsson; Nicole M. Stark; Kristiina Oksman

2007-01-01

In this study, silane cross-linked wood–polyethylene composite profiles were manufactured by reactive extrusion. These composites were evaluated regarding their durability and mechanical properties in comparison with two non-cross-linked wood– polyethylene composites. An addition of only 2% w/w of silane solution during manufacturing was enough to achieve almost 60%...

Improved Dental Implant Drill Durability and Performance Using Heat and Wear Resistant Protective Coatings.

PubMed

Er, Nilay; Alkan, Alper; Ilday, Serim; Bengu, Erman

2018-06-01

The dental implant drilling procedure is an essential step for implant surgery, and frictional heat in bone during drilling is a key factor affecting the success of an implant. The aim of this study was to increase the dental implant drill lifetime and performance by using heat- and wear-resistant protective coatings to decrease the alveolar bone temperature caused by the dental implant drilling procedure. Commercially obtained stainless steel drills were coated with titanium aluminum nitride, diamond-like carbon, titanium boron nitride, and boron nitride coatings via magnetron-sputter deposition. Drilling was performed on bovine femoral cortical bone under the conditions mimicking clinical practice. Tests were performed under water-assisted cooling and under the conditions when no cooling was applied. Coated drill performances and durabilities were compared with those of three commonly used commercial drills with surfaces made from zirconia, black diamond. and stainless steel. Protective coatings with boron nitride, titanium boron nitride, and diamond-like carbon have significantly improved drill performance and durability. In particular, boron nitride-coated drills have performed within safe bone temperature limits for 50 drillings even when no cooling is applied. Titanium aluminium nitride coated drills did not show any improvement over commercially obtained stainless steel drills. Surface modification using heat- and wear-resistant coatings is an easy and highly effective way to improve implant drill performance and durability, which can improve the surgical procedure and the postsurgical healing period. The noteworthy success of different types of coatings is novel and likely to be applicable to various other medical systems.

The quest for durable lesions in catheter ablation of atrial fibrillation - technological advances in radiofrequency catheters and balloon devices.

PubMed

Maurer, Tilman; Kuck, Karl-Heinz

2017-08-01

Atrial fibrillation is the most common cardiac arrhythmia and represents a growing clinical, social and economic challenge. Catheter ablation for symptomatic atrial fibrillation has evolved from an experimental procedure into a widespread therapy and offers a safe and effective treatment option. A prerequisite for durable PVI are transmural and contiguous circumferential lesions around the pulmonary veins. However, electrical reconnection of initially isolated pulmonary veins remains a primary concern and is a dominant factor for arrhythmia recurrence during long-term follow up. Areas covered: This article discusses the physiology of lesion formation using radiofrequency-, cryo- or laser- energy for pulmonary vein isolation and provides a detailed review of recent technological advancements in the field of radiofrequency catheters and balloon devices. Finally, future directions and upcoming developments for the interventional treatment of atrial fibrillation are discussed. Expert commentary: Durable conduction block across deployed myocardial lesions is mandatory not only for PVI but for any other cardiac ablation strategy as well. A major improvement urgently expected is the intraprocedural real-time distinction of durable lesions from interposed gaps with only transiently impaired electrical conduction. Furthermore, a simplification of ablation tools used for PVI is required to reduce the high technical complexity of the procedure.

40 CFR 610.50 - Test configurations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Test configurations. 610.50 Section 610.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Durability Test Procedures § 610.50 Test...

Durability of Bricks Coated with Red mud Based Geopolymer Paste

NASA Astrophysics Data System (ADS)

Singh, Smita; Basavanagowda, S. N.; Aswath, M. U.; Ranganath, R. V.

2016-09-01

The present study is undertaken to assess the durability of concrete blocks coated with red mud - fly ash based geopolymer paste. Concrete blocks of size 200 x 200 x 100mm were coated with geopolymer paste synthesized by varying the percentages of red mud and fly ash. Uncoated concrete blocks were also tested for the durability for comparison. In thermal resistance test, the blocks were subjected to 600°C for an hour whereas in acid resistance test, they were kept in 5% sulphuric acid solution for 4 weeks. The specimens were thereafter studied for surface degradation, strength loss and weight loss. Pastes with red mud percentage greater than 50% developed lot of shrinkage cracks. The blocks coated with 30% and 50% red mud paste showed better durability than the other blocks. The use of blocks coated with red mud - fly ash geopolymer paste improves the aesthetics, eliminates the use of plaster and improves the durability of the structure.

40 CFR 610.50 - Test configurations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Test configurations. 610.50 Section... ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Durability Test Procedures § 610.50 Test... the same test sequence for fuel economy and exhaust emissions as specified in subpart D. Subsequently...

40 CFR 610.50 - Test configurations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Test configurations. 610.50 Section... ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Durability Test Procedures § 610.50 Test... the same test sequence for fuel economy and exhaust emissions as specified in subpart D. Subsequently...

40 CFR 610.50 - Test configurations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Test configurations. 610.50 Section... ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Durability Test Procedures § 610.50 Test... the same test sequence for fuel economy and exhaust emissions as specified in subpart D. Subsequently...

40 CFR 610.50 - Test configurations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Test configurations. 610.50 Section... ECONOMY RETROFIT DEVICES Test Procedures and Evaluation Criteria Durability Test Procedures § 610.50 Test... the same test sequence for fuel economy and exhaust emissions as specified in subpart D. Subsequently...

Laundering durable antibacterial cotton fabrics grafted with pomegranate-shaped polymer wrapped in silver nanoparticle aggregations

NASA Astrophysics Data System (ADS)

Liu, Hanzhou; Lv, Ming; Deng, Bo; Li, Jingye; Yu, Ming; Huang, Qing; Fan, Chunhai

2014-08-01

To improve the laundering durability of the silver functionalized antibacterial cotton fabrics, a radiation-induced coincident reduction and graft polymerization is reported herein where a pomegranate-shaped silver nanoparticle aggregations up to 500 nm can be formed due to the coordination forces between amino group and silver and the wrapping procedure originated from the coincident growth of the silver nanoparticles and polymer graft chains. This pomegranate-shaped silver NPAs functionalized cotton fabric exhibits outstanding antibacterial activities and also excellent laundering durability, where it can inactivate higher than 90% of both E. coli and S. aureus even after 50 accelerated laundering cycles, which is equivalent to 250 commercial or domestic laundering cycles.

Aortic root repair for thoracic aorta false aneurysm following Bentall procedure.

PubMed

Kumar, Sanjay; Jones, Steve; Sivananthan, U M; McGoldrick, J P

2008-08-01

The Bentall procedure for aortic root replacement in Marfan's syndrome is safe and durable. We describe successful repair of periprosthetic valvular leak, 12 years following Bentall repair with composite graft. The aim of this report is to analyse and evaluate technical factors leading to this unusual occurrence.

Determination of the critical plane and durability estimation for a multiaxial cyclic loading

NASA Astrophysics Data System (ADS)

Burago, N. G.; Nikitin, A. D.; Nikitin, I. S.; Yakushev, V. L.

2018-03-01

An analytical procedure is proposed to determine the critical plane orientation according to the Findley criterion for the multiaxial cyclic loading. The cases of in-phase and anti-phase cyclic loading are considered. Calculations of the stress state are carried out for the system of the gas turbine engine compressor disk and blades for flight loading cycles. The formulas obtained are used for estimations of the fatigue durability of this essential element of structure.

Robust Damage-Mitigating Control of Aircraft for High Performance and Structural Durability

NASA Technical Reports Server (NTRS)

Caplin, Jeffrey; Ray, Asok; Joshi, Suresh M.

1999-01-01

This paper presents the concept and a design methodology for robust damage-mitigating control (DMC) of aircraft. The goal of DMC is to simultaneously achieve high performance and structural durability. The controller design procedure involves consideration of damage at critical points of the structure, as well as the performance requirements of the aircraft. An aeroelastic model of the wings has been formulated and is incorporated into a nonlinear rigid-body model of aircraft flight-dynamics. Robust damage-mitigating controllers are then designed using the H(infinity)-based structured singular value (mu) synthesis method based on a linearized model of the aircraft. In addition to penalizing the error between the ideal performance and the actual performance of the aircraft, frequency-dependent weights are placed on the strain amplitude at the root of each wing. Using each controller in turn, the control system is put through an identical sequence of maneuvers, and the resulting (varying amplitude cyclic) stress profiles are analyzed using a fatigue crack growth model that incorporates the effects of stress overload. Comparisons are made to determine the impact of different weights on the resulting fatigue crack damage in the wings. The results of simulation experiments show significant savings in fatigue life of the wings while retaining the dynamic performance of the aircraft.

Improving the durability of a drag-reducing nanocoating by enhancing its mechanical stability.

PubMed

Cheng, Mengjiao; Zhang, Songsong; Dong, Hongyu; Han, Shihui; Wei, Hao; Shi, Feng

2015-02-25

The durability of superhydrophobic surface is a major problem to restrict industrial application of superhydrophobic materials from laboratory research, which can be attributed to a more general issue of mechanical stability for superhydrophobic coatings. Therefore, in order to handle this issue, we have fabricated a mechanically stable drag-reducing coating composed of elastic polydimethylsiloxane (PDMS) and hydrophobic copper particles on model ships, which can resist mechanical abrasion and has displayed a durable drag-reducing effect. In comparison with normal Au superhydrophobic coatings, the as-prepared PDMS/copper coatings showed durable drag reduction performance with a similar drag-reducing rate before (26%) and after (24%) mechanical abrasion. The mechanism for the enhanced mechanical stability and maintained drag reduction of the superhydrophobic surfaces was investigated through characterizations of surface morphology, surface wettability, and water adhesive force evaluation before and after abrasion. This is the first demonstration to realize the application of durable drag reduction by improving the mechanical stability of superhydrophobic coatings. We do believe that superhydrophobic surfaces with good resistance to mechanical abrasion or scratching may draw wide attention and gain significant applications with durable drag-reducing properties.

Nondestructive Evaluation Correlated with Finite Element Analysis

NASA Technical Reports Server (NTRS)

Abdul-Azid, Ali; Baaklini, George Y.

1999-01-01

Advanced materials are being developed for use in high-temperature gas turbine applications. For these new materials to be fully utilized, their deformation properties, their nondestructive evaluation (NDE) quality and material durability, and their creep and fatigue fracture characteristics need to be determined by suitable experiments. The experimental findings must be analyzed, characterized, modeled and translated into constitutive equations for stress analysis and life prediction. Only when these ingredients - together with the appropriate computational tools - are available, can durability analysis be performed in the design stage, long before the component is built. One of the many structural components being evaluated by the NDE group at the NASA Lewis Research Center is the flywheel system. It is being considered as an energy storage device for advanced space vehicles. Such devices offer advantages over electrochemical batteries in situations demanding high power delivery and high energy storage per unit weight. In addition, flywheels have potentially higher efficiency and longer lifetimes with proper motor-generator and rotor design. Flywheels made of fiber-reinforced polymer composite material show great promise for energy applications because of the high energy and power densities that they can achieve along with a burst failure mode that is relatively benign in comparison to those of flywheels made of metallic materials Therefore, to help improve durability and reduce structural uncertainties, we are developing a comprehensive analytical approach to predict the reliability and life of these components under these harsh loading conditions. The combination of NDE and two- and three-dimensional finite element analyses (e.g., stress analyses and fracture mechanics) is expected to set a standardized procedure to accurately assess the applicability of using various composite materials to design a suitable rotor/flywheel assembly.

Moisture Durability with Vapor-Permeable Insulating Sheathing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lepage, R.; Lstiburek, J.

2013-09-01

Exterior sheathing insulation is an effective strategy in increasing the overall R-value of wall assemblies; other benefits include decreasing the effects of thermal bridging and increasing the moisture durability of the built assembly. Vapor-permeable exterior insulation, such as mineral board or expanded polystyrene foam, are one such product that may be used to achieve these benefits. However, uncertainty exists on the effects of inward driven moisture and the interaction of increased sheathing temperatures on the moisture durability of the edifice. To address these concerns, Building Science Corporation (BSC) conducted a series of hygrothermal models for cities representing a range ofmore » different climate zones. This report describes the research project, key research questions, and the procedures utilized to analyse the problems.« less

Durability of ITO-MgF2 Films for Space-Inflatable Polymer Structures

NASA Technical Reports Server (NTRS)

Kerslake, Thomas W.; Waters, Deborah L.; Schieman, David A.; Hambourger, Paul D.

2003-01-01

This paper presents results from ITO-MgF2 film durability evaluations that included tape peel, fold, thermal cycle, and AO exposure testing. Polymer coupon preparation is described as well as ITO-MgF2 film deposition equipment, procedures and film characterization. Durability testing methods are also described. The pre- and post-test condition of the films is assessed visually, microscopically, and electrically. Results show that at 500 ITO - 9 vol% MgF2 film is suitable to protect polymer surfaces, such as those used in space-inflatable structures of the PowerSphere microsatellite concept, during a 1-year Earth orbiting mission. Future plans for ground-based and orbital testing of this film are also discussed.

Effects of chloride additives on the mechanical stability and environmental durability of porous MgF2 thin films

NASA Astrophysics Data System (ADS)

Schütz, F.; Scheurell, K.; Scholz, G.; Kemnitz, E.

2016-09-01

Porous antireflective thin films, prepared of nanoscopic MgF2 sols, exhibit a low refraction index and are useful for various optical applications. Due to their porosity, film stability and durability suffer from mechanical abrasion and water solubility, respectively. Hence, we present approaches of improved mechanical stability of MgF2 layers induced by chloride addition. Antireflective (AR) films were produced by dip-coating followed by thermal treatment. Afterwards, film stability and environmental durability was strained by crockmeter and water stability tests, respectively. In comparison to films prepared from chloride-free MgF2 sols, chloride mingled sols form coatings with increased mechanical stability and a lower solubility.

Progressive fracture of fiber composites

NASA Technical Reports Server (NTRS)

Irvin, T. B.; Ginty, C. A.

1983-01-01

Refined models and procedures are described for determining progressive composite fracture in graphite/epoxy angleplied laminates. Lewis Research Center capabilities are utilized including the Real Time Ultrasonic C Scan (RUSCAN) experimental facility and the Composite Durability Structural Analysis (CODSTRAN) computer code. The CODSTRAN computer code is used to predict the fracture progression based on composite mechanics, finite element stress analysis, and fracture criteria modules. The RUSCAN facility, CODSTRAN computer code, and scanning electron microscope are used to determine durability and identify failure mechanisms in graphite/epoxy composites.

Durability of hardboard siding

Treesearch

Anton TenWolde; Charles Carll

2004-01-01

In response to concerns about hardboard siding failures, a study was performed to assess if performance in a current hardboard industry quality assurance test procedure correlated with in-service performance and how well this performance might be predicted by use of alternative or additional test procedures. A variety of laboratory tests were performed on a large...

[GERD: endoscopic antireflux therapies].

PubMed

Caca, K

2006-08-02

A couple of minimally-invasive, endoscopic antireflux procedures have been developed during the last years. Beside endoscopic suturing these included injection/implantation technique of biopolymers and application of radiofrequency. Radiofrequency (Stretta) has proved only a very modest effect, while implantation techniques have been abandoned due to lack of long-term efficacy (Gatekeeper) or serious side effects (Enteryx). While first generation endoluminal suturing techniques (EndoCinch, ESD) demonstrated a proof of principle their lack of durability, due to suture loss, led to the development of a potentially durable transmural plication technique (Plicator). In a prospective-randomized, sham-controlled trial the Plicator procedure proved superiority concerning reflux symptoms, medication use and esophageal acid exposure (24-h-pH-metry). While long-term data have to be awaited to draw final conclusions, technical improvements will drive innovation in this field.

A nonlinear viscoelastic approach to durability predictions for polymer based composite structures

NASA Technical Reports Server (NTRS)

Brinson, Hal F.

1991-01-01

Current industry approaches for the durability assessment of metallic structures are briefly reviewed. For polymer based composite structures, it is suggested that new approaches must be adopted to include memory or viscoelastic effects which could lead to delayed failures that might not be predicted using current techniques. A durability or accelerated life assessment plan for fiber reinforced plastics (FRP) developed and documented over the last decade or so is reviewed and discussed. Limitations to the plan are outlined and suggestions to remove the limitations are given. These include the development of a finite element code to replace the previously used lamination theory code and the development of new specimen geometries to evaluate delamination failures. The new DCB model is reviewed and results are presented. Finally, it is pointed out that new procedures are needed to determine interfacial properties and current efforts underway to determine such properties are reviewed. Suggestions for additional efforts to develop a consistent and accurate durability predictive approach for FRP structures are outlined.

A nonlinear viscoelastic approach to durability predictions for polymer based composite structures

NASA Technical Reports Server (NTRS)

Brinson, Hal F.; Hiel, C. C.

1990-01-01

Current industry approaches for the durability assessment of metallic structures are briefly reviewed. For polymer based composite structures, it is suggested that new approaches must be adopted to include memory or viscoelastic effects which could lead to delayed failures that might not be predicted using current techniques. A durability or accelerated life assessment plan for fiber reinforced plastics (FRP) developed and documented over the last decade or so is reviewed and discussed. Limitations to the plan are outlined and suggestions to remove the limitations are given. These include the development of a finite element code to replace the previously used lamination theory code and the development of new specimen geometries to evaluate delamination failures. The new DCB model is reviewed and results are presented. Finally, it is pointed out that new procedures are needed to determine interfacial properties and current efforts underway to determine such properties are reviewed. Suggestions for additional efforts to develop a consistent and accurate durability predictive approach for FRP structures is outlined.

Fatigue behaviour analysis for the durability prequalification of strengthening mortars

NASA Astrophysics Data System (ADS)

Bocca, P.; Grazzini, A.; Masera, D.

2011-07-01

An innovative laboratory procedure used as a preliminary design stage for the pre-qualification of strengthening mortars applied to historical masonry buildings is described. In the analysis of the behaviour of masonry structures and their constituent materials, increasing importance has been assumed by the study of the long-term evolution of deformation and mechanical characteristics, which may be affected by both loading and environmental conditions. Through static and fatigue tests on mixed specimens historical brick-reinforced mortar it has been possible to investigate the durability of strengthening materials, in order to select, from a range of alternatives, the most suitable for the historical masonry. Cyclic fatigue stress has been applied to accelerate the static creep and to forecast the corresponding creep behaviour of the historical brick-strengthening mortar system under static long-time loading. This methodology has proved useful in avoiding the errors associated with materials that are not mechanically compatible and guarantees the durability of strengthening work. The experimental procedure has been used effectively in the biggest restoration building site in Europe, the Royal Palace of Venaria, and it is in progress of carrying out at the Special Natural Reserve of the Sacro Monte di Varallo, in Piedmont (Italy).

40 CFR Appendix I to Subpart V of... - Recommended Test Procedures and Test Criteria and Recommended Durability Procedures To...

Code of Federal Regulations, 2013 CFR

2013-07-01

... to the vacuum unit to achieve full diaphragm displacement. Seal vacuum source to unit. There shall be no visible loss of diaphragm displacement or drop in vacuum gauge reading after a 15 second observation. Vacuum purge system and diaphragm displacement adjusting screw holes should be temporarily sealed...

40 CFR Appendix I to Subpart V of... - Recommended Test Procedures and Test Criteria and Recommended Durability Procedures To...

Code of Federal Regulations, 2011 CFR

2011-07-01

... to the vacuum unit to achieve full diaphragm displacement. Seal vacuum source to unit. There shall be no visible loss of diaphragm displacement or drop in vacuum gauge reading after a 15 second observation. Vacuum purge system and diaphragm displacement adjusting screw holes should be temporarily sealed...

40 CFR Appendix I to Subpart V of... - Recommended Test Procedures and Test Criteria and Recommended Durability Procedures To...

Code of Federal Regulations, 2012 CFR

2012-07-01

... to the vacuum unit to achieve full diaphragm displacement. Seal vacuum source to unit. There shall be no visible loss of diaphragm displacement or drop in vacuum gauge reading after a 15 second observation. Vacuum purge system and diaphragm displacement adjusting screw holes should be temporarily sealed...

40 CFR Appendix I to Subpart V of... - Recommended Test Procedures and Test Criteria and Recommended Durability Procedures To...

Code of Federal Regulations, 2014 CFR

2014-07-01

... to the vacuum unit to achieve full diaphragm displacement. Seal vacuum source to unit. There shall be no visible loss of diaphragm displacement or drop in vacuum gauge reading after a 15 second observation. Vacuum purge system and diaphragm displacement adjusting screw holes should be temporarily sealed...

40 CFR Appendix I to Subpart V of... - Recommended Test Procedures and Test Criteria and Recommended Durability Procedures To...

Code of Federal Regulations, 2010 CFR

2010-07-01

... to the vacuum unit to achieve full diaphragm displacement. Seal vacuum source to unit. There shall be no visible loss of diaphragm displacement or drop in vacuum gauge reading after a 15 second observation. Vacuum purge system and diaphragm displacement adjusting screw holes should be temporarily sealed...

40 CFR 610.62 - Driveability tests.

Code of Federal Regulations, 2013 CFR

2013-07-01

... be conducted at zero device-miles for all vehicles included in the durability fleet, and at approximately zero device-miles at low ambient temperatures (0 °F-20 °F). Driveability evaluation procedures...

Shrinkage and durability study of bridge deck concrete.

DOT National Transportation Integrated Search

2010-12-01

The Mississippi Department of Transportation is incorporating changes to material : specifications and construction procedures for bridge decks in an effort to reduce shrinkage : cracking. These changes are currently being implemented into a limited ...

Ceramic thermal protective coating withstands hostile environment of rotating turbine blades

NASA Technical Reports Server (NTRS)

Liebert, C. H.; Stecura, S.

1975-01-01

Ceramic coatings have low thermal conductivity. They provide potential for increased engine performance, reduced fuel consumption, use of less costly materials or construction procedures, and increased life and durability.

Degradation mechanisms and accelerated testing in PEM fuel cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borup, Rodney L; Mukundan, Rangachary

2010-01-01

The durability of PEM fuel cells is a major barrier to the commercialization of these systems for stationary and transportation power applications. Although there has been recent progress in improving durability, further improvements are needed to meet the commercialization targets. Past improvements have largely been made possible because of the fundamental understanding of the underlying degradation mechanisms. By investigating component and cell degradation modes; defining the fundamental degradation mechanisms of components and component interactions new materials can be designed to improve durability. Various factors have been shown to affect the useful life of PEM fuel cells. Other issues arise frommore » component optimization. Operational conditions (such as impurities in either the fuel and oxidant stream), cell environment, temperature (including subfreezing exposure), pressure, current, voltage, etc.; or transient versus continuous operation, including start-up and shutdown procedures, represent other factors that can affect cell performance and durability. The need for Accelerated Stress Tests (ASTs) can be quickly understood given the target lives for fuel cell systems: 5000 hours ({approx} 7 months) for automotive, and 40,000 hrs ({approx} 4.6 years) for stationary systems. Thus testing methods that enable more rapid screening of individual components to determine their durability characteristics, such as off-line environmental testing, are needed for evaluating new component durability in a reasonable turn-around time. This allows proposed improvements in a component to be evaluated rapidly and independently, subsequently allowing rapid advancement in PEM fuel cell durability. These tests are also crucial to developers in order to make sure that they do not sacrifice durability while making improvements in costs (e.g. lower platinum group metal [PGM] loading) and performance (e.g. thinner membrane or a GDL with better water management properties). To achieve a deeper understanding and improve PEM fuel cell durability LANL is conducting research to better define fuel cell component degradation mechanisms and correlate AST measurements to component in 'real-world' situations.« less

Evaluation of alternative snowplowable markers and snowplowing procedures.

DOT National Transportation Integrated Search

2013-06-01

The objectives of this study were to investigate viable alternatives to the currently approved snowplowable raised pavement marker and alternative methods and equipment used to snowplow roadways. The study included evaluating any potential durable an...

Enhancements to pavement marking testing procedures.

DOT National Transportation Integrated Search

2010-08-01

The Oregon Department of Transportation (ODOT) requires performance and durability testing of all pavement : marking materials before they can be applied on construction projects on state highways. Manufacturers apply materials : on a two-year test d...

Using Trial Vocal Fold Injection to Select Vocal Fold Scar Patients Who May Benefit From More Durable Augmentation.

PubMed

Carroll, Thomas L; Dezube, Aaron; Bauman, Laura A; Mallur, Pavan S

2018-02-01

Clinical indications for vocal fold injection augmentation (VFI) are expanding. Prior studies demonstrate the benefit of trial VFI for select causes of glottic insufficiency. No studies have examined trial VFI for glottic insufficiency resulting from true vocal fold (TVF) scar. Retrospective chart review of patients who underwent trial VFI for a dominant pathology of TVF scar causing dysphonia. Patients who subsequently underwent durable augmentation were identified. The primary study outcome was the difference in Voice Handicap Index-10 (VHI-10) score from pretrial VFI to post-durable augmentation. Twenty-eight patients underwent trial VFI for TVF scar, 22 of whom reported a positive response. Fifteen of 22 subjects who underwent durable augmentation had viable data for analysis. Mean VHI-10 improved from 26.9 to 18.6 ( P < .05), for a delta VHI-10 of 8.3, or 30.9% improvement. Twelve of the 15 (80%) showed a clinically significant improvement (delta VHI-10 >5). A trial VFI is a potentially useful, low-risk procedure that appears to help the patient and clinician identify when global augmentation might improve the voice when vocal fold scar is present. Patients who reported successful trial VFI often demonstrated significant improvement in their VHI-10 after subsequent durable augmentation.

40 CFR 86.1824-07 - Durability demonstration procedures for evaporative emissions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In-Use Light-Duty Vehicles, Light-Duty Trucks, and Complete Otto-Cycle Heavy-Duty Vehicles § 86.1824-07...

Collagenase injections for treatment of Dupuytren disease.

PubMed

Hentz, Vincent R

2014-02-01

Palmodigital fasciectomy remains the gold standard. The initial outcome is, in my experience, far more predictable than either NA or enzyme fasciotomy (EF). It is also a more durable treatment. NA and EF can be conceptualized as similar procedures--one uses a needle and the other an enzyme to weaken a cord sufficient to be able to rupture it and thus straighten a contracted joint. Both are less invasive and the hand is quick to recover. Both procedures are equally initially effective. CHH seems to offer greater durability. Today’s patients are often better educated and seek a specific type of treatment, in particular, effective nonoperative treatment. Pharmaceutical companies now market directly and effectively to patients, and this strategy and Internet use have already resulted in an increase in the number of patients searching for practitioners willing to administer and capable of administering collagenase treatment. Copyright © 2014 Elsevier Inc. All rights reserved.

Estimating Durability of Reinforced Concrete

NASA Astrophysics Data System (ADS)

Varlamov, A. A.; Shapovalov, E. L.; Gavrilov, V. B.

2017-11-01

In this article we propose to use the methods of fracture mechanics to evaluate concrete durability. To evaluate concrete crack resistance characteristics of concrete directly in the structure in order to implement the methods of fracture mechanics, we have developed special methods. Various experimental studies have been carried out to determine the crack resistance characteristics and the concrete modulus of elasticity during its operating. A comparison was carried out for the results obtained with the use of the proposed methods and those obtained with the standard methods for determining the concrete crack resistance characteristics.

Modified chloride diffusion model for concrete under the coupling effect of mechanical load and chloride salt environment

NASA Astrophysics Data System (ADS)

Lei, Mingfeng; Lin, Dayong; Liu, Jianwen; Shi, Chenghua; Ma, Jianjun; Yang, Weichao; Yu, Xiaoniu

2018-03-01

For the purpose of investigating lining concrete durability, this study derives a modified chloride diffusion model for concrete based on the odd continuation of boundary conditions and Fourier transform. In order to achieve this, the linear stress distribution on a sectional structure is considered, detailed procedures and methods are presented for model verification and parametric analysis. Simulation results show that the chloride diffusion model can reflect the effects of linear stress distribution of the sectional structure on the chloride diffusivity with reliable accuracy. Along with the natural environmental characteristics of practical engineering structures, reference value ranges of model parameters are provided. Furthermore, a chloride diffusion model is extended for the consideration of multi-factor coupling of linear stress distribution, chloride concentration and diffusion time. Comparison between model simulation and typical current research results shows that the presented model can produce better considerations with a greater universality.

Oxidation of platinum nickel nanowires to improve durability of oxygen-reducing electrocatalysts

DOE PAGES

Alia, Shaun M.; Pylypenko, Svitlana; Dameron, Arrelaine; ...

2016-01-12

In this study, the impact of heat treating platinum-coated nickel (Pt-Ni) nanowires in oxygen is examined to determine the effect on oxygen reduction (ORR) activity and durability. Pt-Ni nanowires exhibit promising ORR mass activities (3 times greater than Pt nanoparticles, 1.5 times greater than U.S. Department of Energy target) both before and after potential cycling for all but the highest annealing temperatures explored. The annealing of Pt-Ni nanowires in oxygen with increasing temperature is found to reduce surface area and ORR activity in comparison to the untreated material, but also reduces activity losses following durability testing. Following potential cycling, unannealedmore » Pt-Ni nanowires show significant losses in surface area (23%) and specific activity (18%) while Pt-Ni nanowires annealed at 200°C show modest increases in surface area (2%) and specific activity (6%) after potential cycling. Increasing annealing temperatures also show a clear trend of decreasing Ni dissolution rates. While oxygen annealing has shown the ability to improve durability of Pt-Ni nanowires, significant Ni dissolution was observed in all samples and suggests oxide passivation while showing promise for improved durability, when employed by itself is insufficient to prevent all contamination concerns involving Ni dissolution.« less

Thulium fiber laser lithotripsy using small spherical distal fiber tips

NASA Astrophysics Data System (ADS)

Wilson, Christopher R.; Hardy, Luke A.; Kennedy, Joshua D.; Irby, Pierce B.; Fried, Nathaniel M.

2016-02-01

This study tests a 100-μm-core fiber with 300-μm-diameter ball tip during Thulium fiber laser (TFL) lithotripsy. The TFL was operated at 1908 nm wavelength with 35-mJ pulse energy, 500-μs pulse duration, and 300-Hz pulse rate. Calcium oxalate/phosphate stone samples were weighed, laser procedure times measured, and ablation rates calculated for ball tip fibers, with comparison to bare tip fibers. Photographs of ball tips were taken before and after each procedure to observe ball tip degradation and determine number of procedures completed before need to replace fiber. Saline irrigation rates and ureteroscope deflection were measured with and without TFL fiber present. There was no statistical difference (P > 0.05) between stone ablation rates for single-use ball tip fiber (1.3 +/- 0.4 mg/s) (n=10), multiple-use ball tip fiber (1.3 +/- 0.5 mg/s) (n=44), and conventional single-use bare tip fibers (1.3 +/- 0.2 mg/s) (n=10). Ball tip durability varied widely, but fibers averaged > 4 stone procedures before decline in stone ablation rates due to mechanical damage at front surface of ball tip. The small fiber diameter did not impact ureteroscope deflection or saline flow rates. The miniature ball tip fiber may provide a cost-effective design for safe fiber insertion through the ureteroscope working channel and the ureter without risk of scope damage or tissue perforation, and without compromising stone ablation efficiency during TFL ablation of kidney stones.

Mid-urethral slings in female incontinence: Current status

PubMed Central

Krlin, Ryan M.; Murphy, Alana M.; Ingber, Michael S.; Vasavada, Sandip P.

2011-01-01

The advent of the mid-urethral sling (MUS) 15 years ago has drastically changed the surgical management of stress urinary incontinence (SUI). Both retropubic and transobturator MUS can be placed in the ambulatory setting with excellent results. The tension-free vaginal tape (TVT) sling has the most robust and long-term data, but more recent literature suggests that the transobturator tape sling may offer comparable efficacy in appropriately selected patients. Single incision sling (SIS) is the newest addition to the MUS group and was developed in an attempt to minimize morbidity and create an anti-incontinence procedure that could be performed in the office. The efficacy of SIS remains unknown as the current literature regarding SIS lacks long-term results and comparative trials. The suprapubic arc sling appears to have equally effective outcomes in at least the short-term when compared with TVT. Although evolution of the SIS has led to a less invasive procedure with decreased post-op pain and reduced recovery time, durability of efficacy could be the endpoint we are sacrificing. Until longer-term data and more quality comparison trials are available, tailoring one's choice of MUS to the individual patient and her unique clinical parameters remains the best option. PMID:22022053

TAVR vs SAVR: Rising Expectations and Changing Indications for Surgery in Response to PARTNER II.

PubMed

Spadaccio, Cristiano; Nappi, Francesco; Sablayrolles, Jean-Louis; Sutherland, Fraser W H

2017-01-01

Despite the criticisms and concerns raised on the data published in the PARTNER II trial and related analyses, we are undeniably witnessing a revolution in the management of aortic valve disease, in which conventional full sternotomy surgical aortic valve replacement (SAVR), with all related complications and clinical burden, will soon become a nonviable option. Several of the findings described in the PARTNER II trial, although considerable as points of incongruence and study biases in comparison with SAVR, could be taken as lessons to found a new course in SAVR and redesign the respective roles of surgery and interventional procedures in aortic disease. In particular, the results of these trials can actually be considered as a stimulus to invest more effort to improve the current surgical practice that should embrace alternative solutions and least invasive approaches to provide a competitive advantage over percutaneous procedures. An analysis of these points in light of the more recent findings on transcatheter valve durability, thrombosis, and postprocedural complications is provided. Considerations on the parallel progress of SAVR and on the need for a behavioral change in the surgical community are discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

Prediction of fracture toughness and durability of adhesively bonded composite joints with undesirable bonding conditions

NASA Astrophysics Data System (ADS)

Musaramthota, Vishal

Advanced composite materials have enabled the conventional aircraft structures to reduce weight, improve fuel efficiency and offer superior mechanical properties. In the past, materials such as aluminum, steel or titanium have been used to manufacture aircraft structures for support of heavy loads. Within the last decade or so, demand for advanced composite materials have been emerging that offer significant advantages over the traditional metallic materials. Of particular interest in the recent years, there has been an upsurge in scientific significance in the usage of adhesively bonded composite joints (ABCJ's). ABCJ's negate the introduction of stress risers that are associated with riveting or other classical techniques. In today's aircraft transportation market, there is a push to increase structural efficiency by promoting adhesive bonding to primary joining of aircraft structures. This research is focused on the issues associated with the durability and related failures in bonded composite joints that continue to be a critical hindrance to the universal acceptance of ABCJ's. Of particular interest are the short term strength, contamination and long term durability of ABCJ's. One of the factors that influence bond performance is contamination and in this study the influence of contamination on composite-adhesive bond quality was investigated through the development of a repeatable and scalable surface contamination procedure. Results showed an increase in the contaminant coverage area decreases the overall bond strength significantly. A direct correlation between the contaminant coverage area and the fracture toughness of the bonded joint was established. Another factor that influences bond performance during an aircraft's service life is its long term strength upon exposure to harsh environmental conditions or when subjected to severe mechanical loading. A test procedure was successfully developed in order to evaluate durability of ABCJ's comprising severe environmental conditioning, fatiguing in ambient air and a combination of both. The bonds produced were durable enough to sustain the tests cases mentioned above when conditioned for 8 weeks and did not experience any loss in strength. Specimens that were aged for 80 weeks showed a degradation of 10% in their fracture toughness when compared to their baseline datasets. The effect of various exposure times needs to be further evaluated to establish the relationship of durability that is associated with the fracture toughness of ABCJ's.

Bare metal stents, durable polymer drug eluting stents, and biodegradable polymer drug eluting stents for coronary artery disease: mixed treatment comparison meta-analysis

PubMed Central

Toklu, Bora; Amoroso, Nicholas; Fusaro, Mario; Kumar, Sunil; Hannan, Edward L; Faxon, David P; Feit, Frederick

2013-01-01

Objective To compare the efficacy and safety of biodegradable polymer drug eluting stents with those of bare metal stents and durable polymer drug eluting stents. Design Mixed treatment comparison meta-analysis of 258 544 patient years of follow-up from randomized trials. Data sources and study selection PubMed, Embase, and Central were searched for randomized trials comparing any of the Food and Drug Administration approved durable polymer drug eluting stents (sirolimus eluting, paclitaxel eluting, cobalt chromium everolimus eluting, platinum chromium everolimus eluting, zotarolimus eluting-Endeavor, and zotarolimus eluting-Resolute) or biodegradable polymer drug eluting stents, with each other or against bare metal stents. Outcomes Long term efficacy (target vessel revascularization, target lesion revascularization) and safety (death, myocardial infarction, stent thrombosis). Landmark analysis at more than one year was evaluated to assess the potential late benefit of biodegradable polymer drug eluting stents. Results From 126 randomized trials and 258 544 patient years of follow-up, for long term efficacy (target vessel revascularization), biodegradable polymer drug eluting stents were superior to paclitaxel eluting stents (rate ratio 0.66, 95% credibility interval 0.57 to 0.78) and zotarolimus eluting stent-Endeavor (0.69, 0.56 to 0.84) but not to newer generation durable polymer drug eluting stents (for example: 1.03, 0.89 to 1.21 versus cobalt chromium everolimus eluting stents). Similarly, biodegradable polymer drug eluting stents were superior to paclitaxel eluting stents (rate ratio 0.61, 0.37 to 0.89) but inferior to cobalt chromium everolimus eluting stents (2.04, 1.27 to 3.35) for long term safety (definite stent thrombosis). In the landmark analysis after one year, biodegradable polymer drug eluting stents were superior to sirolimus eluting stents for definite stent thrombosis (rate ratio 0.29, 0.10 to 0.82) but were associated with increased mortality compared with cobalt chromium everolimus eluting stents (1.52, 1.02 to 2.22). Overall, among all stent types, the newer generation durable polymer drug eluting stents (zotarolimus eluting stent-Resolute, cobalt chromium everolimus eluting stents, and platinum chromium everolimus eluting stents) were the most efficacious (lowest target vessel revascularization rate) stents, and cobalt chromium everolimus eluting stents were the safest with significant reductions in definite stent thrombosis (rate ratio 0.35, 0.21 to 0.53), myocardial infarction (0.65, 0.55 to 0.75), and death (0.72, 0.58 to 0.90) compared with bare metal stents. Conclusions Biodegradable polymer drug eluting stents are superior to first generation durable polymer drug eluting stents but not to newer generation durable polymer stents in reducing target vessel revascularization. Newer generation durable polymer stents, and especially cobalt chromium everolimus eluting stents, have the best combination of efficacy and safety. The utility of biodegradable polymer stents in the context of excellent clinical outcomes with newer generation durable polymer stents needs to be proven. PMID:24212107

Treatment of articular cartilage lesions of the knee by microfracture or autologous chondrocyte implantation: a systematic review.

PubMed

Oussedik, Sam; Tsitskaris, Konstantinos; Parker, David

2015-04-01

We performed a systematic review of the treatment of articular cartilage lesions of the knee by microfracture or autologous chondrocyte implantation to determine the differences in patient outcomes after these procedures. We searched PubMed/Medline, Embase, and The Cochrane Library databases in the period from January 10 through January 20, 2013, and included 34 articles in our qualitative analysis. All studies showed improvement in outcome scores in comparison with baseline values, regardless of the treatment modality. The heterogeneity of the results presented in the studies precluded a meta-analysis. Microfracture appears to be effective in smaller lesions and is usually associated with a greater proportion of fibrocartilage production, which may have an effect on durability and eventual failure. Autologous chondrocyte implantation is an effective treatment that may result in a greater proportion of hyaline-like tissue at the repair site, which may in turn have a beneficial effect on durability and failure; it appears to be effective in larger lesions. Autologous chondrocyte implantation with periosteum has been shown to be associated with symptomatic cartilage hypertrophy more frequently than autologous chondrocyte implantation with collagen membrane. Matrix-associated autologous chondrocyte implantation is technically less challenging than the other techniques available, and in lesions greater than 4 cm(2), it has been shown to be more effective than microfracture. Level IV, systematic review of Level I-IV studies. Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Improved durability of proton exchange membrane fuel cells by introducing Sn (IV) oxide into electrodes using an ion exchange method

NASA Astrophysics Data System (ADS)

Poulsen, M. G.; Larsen, M. J.; Andersen, S. M.

2017-03-01

Electrodes of Proton Exchange Membrane Fuel Cells (PEMFCs), consisting of catalyst-coated gas diffusion layers, were subjected to an optimized ion exchange procedure, in which tin (IV) oxide (SnO2) nanoparticles were introduced into them. Both methanol and sulfuric acid were tested as ion exchange solvents. SnO2 has previously been shown to exhibit radical scavenging abilities towards radicals inside the electrocatalyst layers. Its presence inside the electrodes was confirmed using X-ray photoelectron spectroscopy and X-ray fluorescence. After exposure to an accelerated stress test in a three-electrode setup, the electrodes containing SnO2 were found to have retained approximately 73.0% of their original Pt, while only 53.2% was retained in electrodes treated identically, but without Sn. Similarly, the SnO2-treated electrodes also experienced a smaller loss in electrochemical surface area in comparison to before the accelerated stress test. A membrane electrode assembly (MEA) constructed with a SnO2-containing anode was evaluated over 500 h. The results showed remarkably reduced OCV decay rate and end of test hydrogen crossover compared to the control MEA, indicating that SnO2 aids in impeding membrane thinning and pinhole formation. The results point toward a positive effect of SnO2 on fuel cell durability, by reducing the degradation of the membrane as well as of the ionomer in the electrocatalyst layer.

Pt/Ni(OH)2–NiOOH/Pd multi-walled hollow nanorod arrays as superior electrocatalysts for formic acid electrooxidation† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c5sc02544c Click here for additional data file.

PubMed Central

Xu, Han; Ding, Liang-Xin; Feng, Jin-Xian

2015-01-01

The catalytic activity and durability are crucial for the development of high-performance electrocatalysts. To design electrocatalysts with excellent electroactivity and durability, the structure and composition are two important guiding principles. In this work, novel Pt/Ni(OH)2–NiOOH/Pd multi-walled hollow nanorod arrays (MHNRAs) are successfully synthesized. The unique MHNRAs provide fast transport and short diffusion paths for electroactive species and high utilization rate of catalysts. Because of the special surface and synergistic effects, the Pt/Ni(OH)2–NiOOH/Pd MHNRA electrocatalysts exhibit high catalytic activity, high durability and superior CO poisoning tolerance for the electrooxidation of formic acid in comparison with Pt@Pd MHNRAs, commercial Pt/C, Pd/C and PtRu/C catalysts. PMID:28757980

Long-term survival, valve durability, and reoperation for 4 aortic root procedures combined with ascending aorta replacement.

PubMed

Svensson, Lars G; Pillai, Saila T; Rajeswaran, Jeevanantham; Desai, Milind Y; Griffin, Brian; Grimm, Richard; Hammer, Donald F; Thamilarasan, Maran; Roselli, Eric E; Pettersson, Gösta B; Gillinov, A Marc; Navia, Jose L; Smedira, Nicholas G; Sabik, Joseph F; Lytle, Bruce W; Blackstone, Eugene H

2016-03-01

To evaluate long-term results of aortic root procedures combined with ascending aorta replacement for aneurysms, using 4 surgical strategies. From January 1995 to January 2011, 957 patients underwent 1 of 4 aortic root procedures: valve preservation (remodeling or modified reimplantation, n = 261); composite biologic graft (n = 297); composite mechanical graft (n = 156); or allograft root (n = 243). Seven deaths occurred (0.73%), none after valve-preserving procedures, and 13 strokes (1.4%). Composite grafts exhibited higher gradients than allografts or valve preservation, but the latter 2 exhibited more aortic regurgitation (2.7% biologic and 0% mechanical composite grafts vs 24% valve-preserving and 19% allografts at 10 years). Within 2 to 5 years, valve preservation exhibited the least left ventricular hypertrophy, allograft replacement the greatest; however, valve preservation had the highest early risk of reoperation, allograft replacement the lowest. Patients receiving allografts had the highest risk of late reoperation (P < .05), and those receiving composite mechanical grafts and valve preservation had the lowest. Composite bioprosthesis patients had the highest risk of late death (57% at 15 years vs 14%-26% for the remaining procedures, P < .0001), because they were substantially older and had more comorbidities (P < .0001). These 4 aortic root procedures, combined with ascending aorta replacement, provide excellent survival and good durability. Valve-preserving and allograft procedures have the lowest gradients and best ventricular remodeling, but they have more late regurgitation, and likely, less risk of valve-related complications, such as bleeding, hemorrhage, and endocarditis. Despite the early risk of reoperation, we recommend valve-preserving procedures for young patients when possible. Composite bioprostheses are preferable for the elderly. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Structural design of composite rotor blades with consideration of manufacturability, durability, and manufacturing uncertainties

NASA Astrophysics Data System (ADS)

Li, Leihong

A modular structural design methodology for composite blades is developed. This design method can be used to design composite rotor blades with sophisticate geometric cross-sections. This design method hierarchically decomposed the highly-coupled interdisciplinary rotor analysis into global and local levels. In the global level, aeroelastic response analysis and rotor trim are conduced based on multi-body dynamic models. In the local level, variational asymptotic beam sectional analysis methods are used for the equivalent one-dimensional beam properties. Compared with traditional design methodology, the proposed method is more efficient and accurate. Then, the proposed method is used to study three different design problems that have not been investigated before. The first is to add manufacturing constraints into design optimization. The introduction of manufacturing constraints complicates the optimization process. However, the design with manufacturing constraints benefits the manufacturing process and reduces the risk of violating major performance constraints. Next, a new design procedure for structural design against fatigue failure is proposed. This procedure combines the fatigue analysis with the optimization process. The durability or fatigue analysis employs a strength-based model. The design is subject to stiffness, frequency, and durability constraints. Finally, the manufacturing uncertainty impacts on rotor blade aeroelastic behavior are investigated, and a probabilistic design method is proposed to control the impacts of uncertainty on blade structural performance. The uncertainty factors include dimensions, shapes, material properties, and service loads.

Dicalcium phosphate (CaHPO4·2H2O) precipitation through ortho- or meta-phosphoric acid-etching: effects on the durability and nanoleakage/ultra-morphology of resin-dentine interfaces.

PubMed

Feitosa, Victor Pinheiro; Bazzocchi, Maria Giulia; Putignano, Angelo; Orsini, Giovanna; Luzi, Arlinda Luzi; Sinhoreti, Mário Alexandre Coelho; Watson, Timothy F; Sauro, Salvatore

2013-11-01

To compare the effects of two etching procedures using meta-phosphoric (MPA) or ortho-phosphoric acid (OPA) on dentine demineralisation, resin-dentine bonds durability and interface nanoleakage/ultra-morphology. Middle-dentine specimens were etched using 37% OPA (15s) or 40% MPA (60s) and submitted to infrared spectroscopy (FTIR) or ultra-morphology dye-assisted (calcium-staining) confocal microscopy (Ca-CLSM). A three-step etch-and-rinse adhesive was formulated, applied onto dentine and light-cured for 30s before composite build-up. After 24h, the dentine-bonded specimens were cut into 1mm(2) beams; half were immediately submitted to microtensile bond strength (μTBS) and half stored in DW for six months. The μTBS results were analysed with repeated-measures ANOVA and Tukey's test (p<0.05). Further teeth were bonded and prepared for interface nanoleakage/ultra-morphology confocal evaluation. FTIR and Ca-CLSM analyses showed dicalcium phosphate dihydrate (Brushite) precipitation in MPA-etched dentine and on the bottom (front of demineralisation) of the OPA-etched dentine. Statistical analysis showed similar μTBS for both etching procedures after 24h. The μTBS of specimens in OPA-group dropped significantly (p<0.05) after six month; the specimens in the MPA group showed no statistically difference (p>0.05). CLSM depicted no evident sign of nanoleakage within the resin-dentine interface of the MPA-treated specimens, while the specimens in OPA-group presented intense nanoleakage and interface degradation. The use of MPA (60s) as an alternative dentine conditioning agent in etch-and-rinse bonding procedures may be a suitable strategy to create more durable resin-dentine bonds. Copyright © 2013 Elsevier Ltd. All rights reserved.

Manufacturing of Low Cost, Durable Membrane Electrode Assemblies Engineered for Rapid Conditioning

DOE Office of Scientific and Technical Information (OSTI.GOV)

Busby, Colin

Over the past 20 years significant progress in membrane-electrode assembly (MEA) technology development for polymer electrolyte fuel cells (PEMFCs) has resulted in the PEMFC technology approaching a commercial reality for transportation applications. However, there remain two primary technical challenges to be addressed in the MEA. First and foremost is meeting the automotive cost targets: Producing a fuel cell stack cost competitive with today’s internal combustion engine. In addition to the material cost, MEA (and other components) and stack assembly production methods must be amenable for use in low cost, high speed, automotive assembly line. One impediment to this latter goalmore » is that stack components must currently go through a long and tedious conditioning procedure before they produce optimal power. This so-called “break-in” can take many hours, and can involve quite complex voltage, temperature and/or pressure steps. These break-in procedures must be simplified and the time required reduced if fuel cells are to become a viable automotive engine. The second challenge is to achieve the durability targets in real-world automotive duty cycle operations. Significant improvements in cost, break-in time, and durability for the key component of fuel cell stacks, MEAs were achieved in this project. Advanced modeling was used to guide design of the new MEA to maximize performance and durability. A new, innovative process and manufacturing approach utilizing direct in-line coating using scalable, cost-competitive, continuous high volume 3-layer rolled-good manufacturing processes was developed and validated by single cell and short stack testing. In addition, the direct coating methods employed were shown to reduce the cost for sacrificial films. Furthermore, Gore has demonstrated a 10 µm reinforced membrane that is used in the new low-cost process and can meet automotive power density and durability targets. Across a wide range of operating conditions, the direct-coated MEA outperformed the commercial baseline MEA, and did so through a process that delivers MEAs at $92.35/m2 at a volume of 500,000 systems per year, according to Strategic Analysis (SA) estimates.« less

Green technology for durable finishing of viscose fibers via self-formation of AuNPs.

PubMed

Emam, Hossam E; El-Hawary, Nancy S; Ahmed, Hanan B

2017-03-01

Sensitivity of dyes' colors to the surrounding environment causes lower durability and stability of color, which reflects the importance of durable finishing treatment. Current technique offered antimicrobial/durable finishing of viscose fibers through direct formation of AuNPs inside fibers macromolecules without using any external agents. By using the reducing properties of cellulose in viscose, Au +3 was reduced to AuNPs and CHO/OH of cellulose subsequently were oxidized to COOH. For comparison, two different media were used; aqueous and alkaline. Increasing the reactivity and accessibility of cellulose macromolecules in alkali leaded to enlargement of the reduction process and more incorporation of AuNPs. Size of AuNPs inside fiber was recorded to be in range of 22-112nm and 14-100nm, in case of using aqueous and alkaline medium, respectively. Structure and properties of fibers were not changed by treatment according to XRD and ATR-FTIR data. The treated fibers were acquired durable violet color by the action of LSPR for AuNPs and darker color obtained using higher Au +3 concentration. The treated fibers exhibited good inhibition against different pathogenic microbes including bacteria and fungi. One-pot, quite simple, inexpensive, green and industrial viable are the significant advantages of the current technique for viscose finishing (pigmentation and antimicrobial action). Copyright © 2016 Elsevier B.V. All rights reserved.

40 CFR 86.1825-01 - Durability demonstration procedures for refueling emissions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... shall use good engineering judgment in determining this process. (a) Service accumulation method. (1.... The manufacturer shall use good engineering judgement in developing this method. (2) The manufacturers... programs, all emission control components and systems (including both hardware and software) must be...

Visual Motion Perception and Visual Information Processing

DTIC Science & Technology

1993-12-31

tradi- tionally called the "span of apprehension" (Kulpe, 1904; Durable Storage Wundt , 1899). However, a partial-report procedure demon- strates...Gehrig. P. (1992). On the time course Wundt . W. (1899). Zur Kritik tachistoskopischer Versuche [A crit- of perceptual information that results from a

Improved Thermal Cycling Durability of Thermal Barrier Coatings Manufactured by PS-PVD

NASA Astrophysics Data System (ADS)

Rezanka, S.; Mauer, G.; Vaßen, R.

2014-01-01

The plasma spray-physical vapor deposition (PS-PVD) process is a promising method to manufacture thermal barrier coatings (TBCs). It fills the gap between traditional thermal spray processes and electron beam physical vapor deposition (EB-PVD). The durability of PS-PVD manufactured columnar TBCs is strongly influenced by the compatibility of the metallic bondcoat (BC) and the ceramic TBC. Earlier investigations have shown that a smooth BC surface is beneficial for the durability during thermal cycling. Further improvements of the bonding between BC and TBC could be achieved by optimizing the formation of the thermally grown oxide (TGO) layer. In the present study, the parameters of pre-heating and deposition of the first coating layer were investigated in order to adjust the growth of the TGO. Finally, the durability of the PS-PVD coatings was improved while the main advantage of PS-PVD, i.e., much higher deposition rate in comparison to EB-PVD, could be maintained. For such coatings, improved thermal cycling lifetimes more than two times higher than conventionally sprayed TBCs, were measured in burner rigs at ~1250 °C/1050 °C surface/substrate exposure temperatures.

Natural durability of some woods used in Hawaii...preliminary findings

Treesearch

Roger G. Skolmen

1968-01-01

Six imported and eight Hawaii-grown species are being tested for their natural resistance to decay and insect attack. Damage to the heartwood has progressed far enough in 4 years to allow comparisons among some of the species.

21 CFR 1002.30 - Records to be maintained by manufacturers.

Code of Federal Regulations, 2010 CFR

2010-04-01

... (CONTINUED) RADIOLOGICAL HEALTH RECORDS AND REPORTS Manufacturers' Records § 1002.30 Records to be maintained... procedures with respect to electronic product radiation safety. (2) Records of the results of tests for... increase electronic product radiation emission, records of the results of tests for durability and...

40 CFR 86.1824-08 - Durability demonstration procedures for evaporative emissions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... deterioration rate and emission level that effectively represents a significant majority of the distribution of... stabilize the permeability of all non-metallic fuel and evaporative system components to the mileage... permeability of evaporative and fuel system components. The manufacturer must also provide information...

40 CFR 86.1824-08 - Durability demonstration procedures for evaporative emissions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... deterioration rate and emission level that effectively represents a significant majority of the distribution of... stabilize the permeability of all non-metallic fuel and evaporative system components to the mileage... permeability of evaporative and fuel system components. The manufacturer must also provide information...

40 CFR 86.1824-08 - Durability demonstration procedures for evaporative emissions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... deterioration rate and emission level that effectively represents a significant majority of the distribution of... stabilize the permeability of all non-metallic fuel and evaporative system components to the mileage... permeability of evaporative and fuel system components. The manufacturer must also provide information...

40 CFR 86.1825-01 - Durability demonstration procedures for refueling emissions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... life. The manufacturer shall use good engineering judgment in determining this process. (a) Service... full useful life. The manufacturer shall use good engineering judgement in developing this method. (2... accumulation programs, all emission control components and systems (including both hardware and software) must...

40 CFR 86.1825-01 - Durability demonstration procedures for refueling emissions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... life. The manufacturer shall use good engineering judgment in determining this process. (a) Service... full useful life. The manufacturer shall use good engineering judgement in developing this method. (2... accumulation programs, all emission control components and systems (including both hardware and software) must...

40 CFR 86.1825-01 - Durability demonstration procedures for refueling emissions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... life. The manufacturer shall use good engineering judgment in determining this process. (a) Service... full useful life. The manufacturer shall use good engineering judgement in developing this method. (2... accumulation programs, all emission control components and systems (including both hardware and software) must...

FR Performance of New Fire-off on PET/CO blend fabrics

NASA Astrophysics Data System (ADS)

Atakan, R.; Çelebi, E.; Ozcan, G.; Soydan, N.; Sarac, A. S.

2017-10-01

This paper represents the investigation on flame retardancy performance and durability of polyester/cotton (P/C) fabrics treated with a novel halogen/formaldehyde free, P-N synergetic FR finishing agent called New Fire-off. 100 % Cotton, 100 % Polyester and three different blend P/C fabrics were chosen in this study. Fabric samples were treated with New Fire-off through pad-dry-cure process. Flammability and thermal properties of the treated samples with New Fire-off were tested according to relevant ISO standard and procedures. The obtained results showed that this new finishing formulation is a good char-forming agent. However, further studies are required to achieve washing durability for the P/C blends.

Viscoelastic behavior and lifetime (durability) predictions. [for laminated fiber reinforced plastics

NASA Technical Reports Server (NTRS)

Brinson, R. F.

1985-01-01

A method for lifetime or durability predictions for laminated fiber reinforced plastics is given. The procedure is similar to but not the same as the well known time-temperature-superposition principle for polymers. The method is better described as an analytical adaptation of time-stress-super-position methods. The analytical constitutive modeling is based upon a nonlinear viscoelastic constitutive model developed by Schapery. Time dependent failure models are discussed and are related to the constitutive models. Finally, results of an incremental lamination analysis using the constitutive and failure model are compared to experimental results. Favorable results between theory and predictions are presented using data from creep tests of about two months duration.

Measure Guideline: Guidance on Taped Insulating Sheathing Drainage Planes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grin, A.; Lstiburek, J.

This guide provides information and recommendations to the following groups: insulation contractors; general contractors; builders; home remodelers; mechanical contractors; and homeowners, as a guide to the work that needs to be done. The order of work completed during home construction and retrofit improvements is important. Health and safety issues must be addressed first and are more important than durability issues. And durability issues are more important than saving energy. Not all techniques can apply to all houses. Special conditions will require special action. Some builders or homeowners will wish to do more than the important but basic retrofit strategies outlinedmore » by this guide. The following are best practice and product recommendations from the interviewed contractors and homebuilders who collectively have a vast amount of experience. Three significant items were discussed with the group which are required to make taped insulating sheathing a simple, long term, and durable drainage plane: 1. Horizontal joints should be limited or eliminated wherever possible; 2. Where a horizontal joint exists use superior materials; 3. Frequent installation inspection and regular trade training are required to maintain proper installation. Section 5 of this measure guideline contains the detailed construction procedure for the three recommended methods to effectively seal the joints in exterior insulating sheathing to create a simple, long term, and durable drainage plane.« less

Transcatheter valve underexpansion limits leaflet durability: implications for valve-in-valve procedures

PubMed Central

Martin, Caitlin; Sun, Wei

2016-01-01

Transcatheter aortic valve (TAV) implantation within a failed bioprosthetic valve is a growing trend for high-risk patients. The non-compliant stent of the previous prosthesis may prevent full expansion of the TAV, which has been shown to distort the leaflet configuration, and has been hypothesized to adversely affect durability. In this study, TAV leaflet fatigue damage under cyclic pressurization in the setting of stent underexpansion by 0 (fully expanded), 1, 2 and 3 mm was simulated using finite element analysis to test this hypothesis. In the 2 and 3 mm underexpanded devices, the TAV leaflets exhibited severe pin-wheeling during valve closure, which increased leaflet stresses dramatically, and resulted in accelerated fatigue damage of the leaflets. The leaflet fatigue damage in the 1 mm underexpanded case was similar to that in the fully expanded case. Clinically a range of 10% to 15% underexpansion is generally considered acceptable; however, it was observed in this study that ≥2 mm (≥9.1%) underexpansion, will significantly impact device durability. Further study is necessary to determine the impact of various deployment conditions, i.e. non-uniform and non-circular deployments and different implantation heights, on differing TAV devices, but it is clear that the normal TAV leaflet configuration must be preserved in order to preserve durability. PMID:27734178

40 CFR 86.1823-08 - Durability demonstration procedures for exhaust emissions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In... § 86.1801. Eligible small volume manufacturers or small volume test groups may optionally meet the...

40 CFR 86.1823-08 - Durability demonstration procedures for exhaust emissions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In... § 86.1801. Eligible small volume manufacturers or small volume test groups may optionally meet the...

40 CFR 86.1824-08 - Durability demonstration procedures for evaporative emissions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... for evaporative emissions. Eligible small-volume manufacturers or small-volume test groups may...-based measurements except the bleed emission test. The standard for bleed emissions applies for the full... manufacturer must conduct at least one evaporative emission test at each of the five different mileage points...

40 CFR 86.1824-08 - Durability demonstration procedures for evaporative emissions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... the applicability provisions of § 86.1801. Eligible small volume manufacturers or small volume test... manufacturer must conduct at least one evaporative emission test at each of the five different mileage points... the highest mileage point run during mileage accumulation (e.g. the full useful life mileage...

40 CFR 86.1824-01 - Durability demonstration procedures for evaporative emissions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... over their full useful life. The manufacturer shall use good engineering judgment in determining this... actual use over its full useful life. The manufacturer shall use good engineering judgement in developing... hardware and software) must be installed and operating for the entire mileage accumulation period. (ii...

40 CFR 86.1824-01 - Durability demonstration procedures for evaporative emissions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... over their full useful life. The manufacturer shall use good engineering judgment in determining this... actual use over its full useful life. The manufacturer shall use good engineering judgement in developing... hardware and software) must be installed and operating for the entire mileage accumulation period. (ii...

40 CFR 86.1824-01 - Durability demonstration procedures for evaporative emissions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... their full useful life. The manufacturer shall use good engineering judgment in determining this process... actual use over its full useful life. The manufacturer shall use good engineering judgement in developing... hardware and software) must be installed and operating for the entire mileage accumulation period. (ii...

Experimental test program for evaluation of solid lubricant coating as applied to compliant foil gas bearings to 315 deg C

NASA Technical Reports Server (NTRS)

Wagner, R. C.

1985-01-01

An experimental apparatus and test procedure was developed to compare the performance of two solid lubricant coatings for air lubricated compliant foil gas bearings in the temperature range of 25 to 315 C. Polyimide bonded additive (SBGC) were tested extensively for durability and frictional characteristics. A partial arc bearing constructed of Inconel X-750 was coated on the bore with one of these coatings. The foil was subjected to repeated start/stop cycles. Performance comparisons reveal that although both coatings survive thousands of start/stop cycles, only the PBGF coated bearing achieves the specified 9000 start/stops. There is enough wear on the SBGC coated bearing to warrant termination of the test prior to 9000 start/stop cycles due to coating failure. The frictional characteristics of the PBGF are better at the elevated temperatures than at lower temperatures; a marked increase in sliding friction occurs as the temperature decreases. The SBGC maintains relatively constant frictional characteristics independent of operating temperature.

Quality assessment for recycling aggregates from construction and demolition waste: An image-based approach for particle size estimation.

PubMed

Di Maria, Francesco; Bianconi, Francesco; Micale, Caterina; Baglioni, Stefano; Marionni, Moreno

2016-02-01

The size distribution of aggregates has direct and important effects on fundamental properties of construction materials such as workability, strength and durability. The size distribution of aggregates from construction and demolition waste (C&D) is one of the parameters which determine the degree of recyclability and therefore the quality of such materials. Unfortunately, standard methods like sieving or laser diffraction can be either very time consuming (sieving) or possible only in laboratory conditions (laser diffraction). As an alternative we propose and evaluate the use of image analysis to estimate the size distribution of aggregates from C&D in a fast yet accurate manner. The effectiveness of the procedure was tested on aggregates generated by an existing C&D mechanical treatment plant. Experimental comparison with manual sieving showed agreement in the range 81-85%. The proposed technique demonstrated potential for being used on on-line systems within mechanical treatment plants of C&D. Copyright © 2015 Elsevier Ltd. All rights reserved.

Basalt fiber reinforced polymer composites: Processing and properties

NASA Astrophysics Data System (ADS)

Liu, Qiang

A high efficiency rig was designed and built for in-plane permeability measurement of fabric materials. A new data derivation procedure to acquire the flow fluid pattern in the experiment was developed. The measurement results of the in-plane permeability for basalt twill 31 fabric material showed that a high correlation exists between the two principal permeability values for this fabric at 35% fiber volume fraction. This may be the most important scientific contribution made in this thesis. The results from radial measurements corresponded quite well with those from Unidirectional (UD) measurements, which is a well-established technique. No significant differences in mechanical properties were found between basalt fabric reinforced polymer composites and glass composites reinforced by a fabric of similar weave pattern. Aging results indicate that the interfacial region in basalt composites may be more vulnerable to environmental damage than that in glass composites. However, the basalt/epoxy interface may have been more durable than the glass/epoxy interface in tension-tension fatigue because the basalt composites have significantly longer fatigue life. In this thesis, chapter I reviews the literature on fiber reinforced polymer composites, with concentration on permeability measurement, mechanical properties and durability. Chapter II discusses the design of the new rig for in-plane permeability measurement, the new derivation procedure for monitoring of the fluid flow pattern, and the permeability measurement results. Chapter III compares the mechanical properties and durability between basalt fiber and glass fiber reinforced polymer composites. Lastly, chapter IV gives some suggestions and recommendations for future work.

High Ethanol Fuel Endurance: A Study of the Effects of Running Gasoline with 15% Ethanol Concentration in Current Production Outboard Four-Stroke Engines and Conventional Two-Stroke Outboard Marine Engines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hilbert, D.

2011-10-01

Three Mercury Marine outboard marine engines were evaluated for durability using E15 fuel -- gasoline blended with 15% ethanol. Direct comparison was made to operation on E0 (ethanol-free gasoline) to determine the effects of increased ethanol on engine durability. Testing was conducted using a 300-hour wide-open throttle (WOT) test protocol, a typical durability cycle used by the outboard marine industry. Use of E15 resulted in reduced CO emissions, as expected for open-loop, non-feedback control engines. HC emissions effects were variable. Exhaust gas and engine operating temperatures increased as a consequence of leaner operation. Each E15 test engine exhibited some deteriorationmore » that may have been related to the test fuel. The 9.9 HP, four-stroke E15 engine exhibited variable hydrocarbon emissions at 300 hours -- an indication of lean misfire. The 300HP, four-stroke, supercharged Verado engine and the 200HP, two-stroke legacy engine tested with E15 fuel failed to complete the durability test. The Verado engine failed three exhaust valves at 285 endurance hours while the 200HP legacy engine failed a main crank bearing at 256 endurance hours. All E0-dedicated engines completed the durability cycle without incident. Additional testing is necessary to link the observed engine failures to ethanol in the test fuel.« less

Evaluation of Temporary Wound Dressings for Adherence, Durability and Autografting on Sulfur Mustard-Induced Lesions in Weanling Swine

DTIC Science & Technology

2000-12-01

interpretation of the May 7, 1996 meeting with Carl Olson, Tim Hayes, Tom Dreier, Dave Stitcher , and Frances Reid. This procedure of decontamination and proof...with Carl Olson, Tim Hayes, Tom Dreier, Dave Stitcher , and Frances Reid. TASK 33 DECONTAMINATION PROCEDURE AND PROOF OF DECONTAMINATION Decontamination...two of you, Mr. Stitcher and Dr. Estep to share our results and resolve any safety issues. Thanks, and M-3 have a good weekend! John S. Graham John S

Application of High Performance Computing for Simulations of N-Dodecane Jet Spray with Evaporation

DTIC Science & Technology

2016-11-01

sprays and develop a predictive theory for comparison to measurements in the laboratory of turbulent diesel sprays. 15. SUBJECT TERMS high...models into future simulations of turbulent jet sprays and develop a predictive theory for comparison to measurements in the lab of turbulent diesel ...A critical component of maintaining performance and durability of a diesel engine involves the formation of a fuel-air mixture as a diesel jet spray

Laboratory comparison of several tests for evaluating the transport properties of concrete.

DOT National Transportation Integrated Search

2006-01-01

The transport properties of concrete are a primary element in determining the durability of concrete. In this study, several new test methods that directly measure aspects of fluid and ionic transport in concrete were examined. ASTM C 1543 and ASTM C...

Evaluation of curing compound application time on concrete surface durability.

DOT National Transportation Integrated Search

2015-03-01

The effect of curing compound application time after concrete finishing was examined in the study. Times of 30 minutes, 2 hours and 4 hours were considered and repeatability was evaluated with comparisons to a Phase I portion of the study. Scaling re...

Development of a multiple immunoaffinity column for simultaneous determination of multiple mycotoxins in feeds using UPLC-MS/MS.

PubMed

Hu, Xiaofeng; Hu, Rui; Zhang, Zhaowei; Li, Peiwu; Zhang, Qi; Wang, Min

2016-09-01

A sensitive and specific immunoaffinity column to clean up and isolate multiple mycotoxins was developed along with a rapid one-step sample preparation procedure for ultra-performance liquid chromatography-tandem mass spectrometry analysis. Monoclonal antibodies against aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, zearalenone, ochratoxin A, sterigmatocystin, and T-2 toxin were coupled to microbeads for mycotoxin purification. We optimized a homogenization and extraction procedure as well as column loading and elution conditions to maximize recoveries from complex feed matrices. This method allowed rapid, simple, and simultaneous determination of mycotoxins in feeds with a single chromatographic run. Detection limits for these toxins ranged from 0.006 to 0.12 ng mL(-1), and quantitation limits ranged from 0.06 to 0.75 ng mL(-1). Concentration curves were linear from 0.12 to 40 μg kg(-1) with correlation coefficients of R (2) > 0.99. Intra-assay and inter-assay comparisons indicated excellent repeatability and reproducibility of the multiple immunoaffinity columns. As a proof of principle, 80 feed samples were tested and several contained multiple mycotoxins. This method is sensitive, rapid, and durable enough for multiple mycotoxin determinations that fulfill European Union and Chinese testing criteria.

Nine-Month Outcomes of the DURABILITY Iliac Study on Self-Expanding Stents for Symptomatic Peripheral Artery Disease.

PubMed

Faries, Peter; Jaff, Michael; Peeters, Patrick; Khatib, Yazan; Roberts, David; Bosiers, Marc; Malik, Rajesh; Ravin, Reid; Rundback, John

2018-04-17

The DURABILITY Iliac clinical study evaluated the safety and effectiveness of two nitinol self-expanding stents for the treatment of atherosclerotic common and external iliac artery lesions up to 10 cm in length and >50% stenosis in subjects with Rutherford Classification peripheral arterial disease stages 2-4. DURABILITY Iliac was a prospective, multicenter, core lab adjudicated, nonrandomized clinical study enrolling 75 subjects from 15 sites in the United States and Europe. Clinical follow-up visits were at 30 days, 9 months, and 1, 2, and 3 years post procedure. The primary outcome measured was the major adverse event rate (MAE) at 9 months, defined as a composite of periprocedural death, in-hospital myocardial infarction (MI), clinically-driven target lesion revascularization (CD-TLR), and amputation of the treated limb through 9 months post-procedure. Secondary outcomes included primary patency rate at 9 months, clinically-driven target vessel revascularization (CD-TVR), change in ankle-brachial index, and change in Walking Impairment Questionnaire score at 30 days and 9 months. Device success was defined as the ability to deploy the stent as intended at the treatment site. The MAE rate at 9 months was 1.3% (1/75), with 1 subject experiencing a CD-TLR. No periprocedural deaths, myocardial infarctions, or amputations were reported. Primacy patency at 9 months was 95.8%. Freedom from CD-TVR was 98.6% at 9 months. Subjects improved in Walking Impairment Questionnaire scores for all categories (walking impairment, walking speed, walking distance, and stair climbing) at the 30-day and 9-month visit. Device success was 100%. The 9-month results of the DURABILITY Iliac study demonstrate the safety and effectiveness of 2 nitinol self-expanding stents for the treatment of atherosclerotic lesions of the common and external iliac arteries. Copyright © 2018. Published by Elsevier Inc.

Endoscopic Injection of Low Dose Triamcinolone: a Simple, Minimally Invasive and Effective Therapy for Interstitial Cystitis with Hunner Lesions.

PubMed

Funaro, Michael G; King, Alexandra N; Stern, Joel N H; Moldwin, Robert M; Bahlani, Sonia

2018-05-18

To investigate the efficacy of low dose triamcinolone injection for effectiveness and durability in interstitial cystitis/bladder pain syndrome (IC/BPS) patients with Hunner Lesions (HL). Clinical data from patients with HL who underwent endoscopic submucosal injection of triamcinolone were reviewed: Demographics, pre/post operative pain and nocturia scores, and long-term clinical outcomes were assessed. Duration of response was estimated by time to repeat procedure. Kaplan-Meier estimator was used to evaluate time to repeat procedure. 36 patients who received injections of triamcinolone between 2011 and 2015 were included. Median age±SD of patients was 61.5±12.0 years 23; 28 (77.8%) of patients were female and 8 (22.2%) were male. 26 patients (72.2%) received only 1 set of injections, 8 (22.2%) received 2 sets of injections, and 2 (5.56%) received 3 or more sets of injections. Average time between injections in those receiving more than one set of injections was 344.9 days (median: 313.5, range: 77-714). Pre-procedural pain scores were 8.3±1.2 (mean±SD) on Likert pain scale (0-10), and mean post-procedural pain scores at approximately one month were 3.8±2.2 p<0.001. Mean pre-procedural nocturia bother scores were 7.5±2.0 and mean post-procedural nocturia bother scores were 5.1±2.5) p<0.001. Endoscopic submucosal injection of low dose triamcinolone in IC/BPS patients with HL is an effective and durable adjunct to existing treatment modalities. This approach is associated with low morbidity and can be performed on an outpatient basis. Copyright © 2018. Published by Elsevier Inc.

Comparison of Radiofrequency-targeted Vertebral Augmentation With Balloon Kyphoplasty for the Treatment of Vertebral Compression Fractures: 2-Year Results.

PubMed

Bornemann, Rahel; Jansen, Tom R; Kabir, Koroush; Pennekamp, Peter H; Stüwe, Brit; Wirtz, Dieter C; Pflugmacher, Robert

2017-04-01

A retrospective study. The aim of this study was the evaluation of the safety and effectiveness of radiofrequency-targeted vertebral augmentation (RF-TVA) in comparison with balloon kyphoplasty (BK) for the treatment of acute painful vertebral compression fractures (VCFs) on the basis of matched pairs. Vertebroplasty and BK are the common surgical interventions for the treatment of VCF. Both are effective and safe but pose some risks such as adjacent fractures and cement leakage. In 2009, RF-TVA was introduced as an innovative augmentation procedure for the treatment of VCF. A total of 192 patients (116 female; 51-90 y) with VCF (n=303) at 1 to 3 levels were treated with RF-TVA or BK. Functionality (Oswestry Disability Index), pain (visual analogue scale), vertebral height (anterior, middle), and kyphotic angle were evaluated over a 2-year period (postoperatively, 3-4 d, 3, 6, 12, and 24 mo). In addition, operating time and occurrence of cement leakage were recorded. Pain and functionality were significantly improved after both treatments. In both groups, there was an increase in the vertebral height and a decrease in the kyphotic angle, which remained relatively consistent during 24 months. The incidence of cement leakage was 9.4% (n=9) in the RF-TVA group and 24.0% (n=25) in the BK group. The mean operating time with radiofrequency kyphoplasty was 25.9±9.9 minutes, and with balloon kyphoplasty 48.0±18.4 minutes. RF-TVA is a safe and effective procedure for the treatment of vertebral compression fractures when compared with BK. Improvement in pain and functional scores after RF-TVA are durable through 24 months postprocedure and remained better than those after BK at long-term follow-up. Operating time for RF-TVA is shorter and the risk of cement leakage is lower. Both procedures provided similar results in vertebral height restoration and reduction in the kyphotic angle.

Comparison of spacing factors as measured by the air-void analyzer and ASTM C457.

DOT National Transportation Integrated Search

2015-12-01

Freezing and thawing cycles will result in damage to concrete that is saturated : unless the concrete is properly entrained with small and well-dispersed air : voids. Durable concrete subject to cycles of freezing and thawing must : have an air-void ...

Contact and Bending Durability Calculation for Spiral-Bevel Gears

NASA Technical Reports Server (NTRS)

Vijayakar, Sandeep

2016-01-01

The objective of this project is to extend the capabilities of the gear contact analysis solver Calyx, and associated packages Transmission3D, HypoidFaceMilled, HypoidFaceHobbed. A calculation process for the surface durability was implemented using the Dowson-Higginson correlation for fluid film thickness. Comparisons to failure data from NASA's Spiral Bevel Gear Fatigue rig were carried out. A bending fatigue calculation has been implemented that allows the use of the stress-life calculation at each individual fillet point. The gears in the NASA test rig did not exhibit any bending fatigue failure, so the bending fatigue calculations are presented in this report by using significantly lowered strength numbers.

High-temperature adult-plant resistance, the key for sustainable control of stripe rust

USDA-ARS?s Scientific Manuscript database

High-temperature adult-plant (HTAP) resistance expresses when plants grow old and the weather becomes warm. This non-race specific and durable type of resistance has been used successfully in control of wheat stripe rust in the U.S. since early 1960s. This article describes practical procedures f...

40 CFR 86.1823-01 - Durability demonstration procedures for exhaust emissions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (including both hardware and software) must be installed and operating for the entire mileage accumulation... decimal places) from the regression analysis; the result shall be rounded to three-decimal places of... less than one shall be changed to one for the purposes of this paragraph. (2) An additive DF will be...

40 CFR 86.1823-01 - Durability demonstration procedures for exhaust emissions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... intermediate useful life and shall be consistent with good engineering judgment. The Administrator will approve... (including both hardware and software) must be installed and operating for the entire mileage accumulation... according to the provisions of § 86.1839-01 using good engineering judgment. (2) For the 2001, 2002, and...

40 CFR 86.1823-01 - Durability demonstration procedures for exhaust emissions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... intermediate useful life and shall be consistent with good engineering judgment. The Administrator will approve... (including both hardware and software) must be installed and operating for the entire mileage accumulation... according to the provisions of § 86.1839-01 using good engineering judgment. (2) For the 2001, 2002, and...

40 CFR 86.1823-01 - Durability demonstration procedures for exhaust emissions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... useful life and shall be consistent with good engineering judgment. The Administrator will approve the... (including both hardware and software) must be installed and operating for the entire mileage accumulation... according to the provisions of § 86.1839-01 using good engineering judgment. (2) For the 2001, 2002, and...

Advances in Thin Film Thermocouple Durability Under High Temperature and Pressure Testing Conditions

NASA Technical Reports Server (NTRS)

Martin, Lisa C.; Fralick, Gustave C.; Taylor, Keith F.

1999-01-01

Thin film thermocouples for measuring material surface temperature have been previously demonstrated on several material systems and in various hostile test environments. A well-developed thin film fabrication procedure utilizing shadow masking for patterning the sensors elements had produced thin films with sufficient durability for applications in high temperature and pressure environments that exist in air-breathing and hydrogen-fueled burner rig and engine test facilities. However, while shadow masking had been a reliable method for specimens with flat and gently curved surfaces, it had not been consistently reliable for use on test components with sharp contours. This work reports on the feasibility of utilizing photolithography processing for patterning thin film thermocouples. Because this patterning process required changes in the thin film deposition process from that developed for shadow masking, the effect of these changes on thin film adherence during burner rig testing was evaluated. In addition to the results of changing the patterning method, the effects on thin film adherence of other processes used in the thin film fabrication procedure is also presented.

A carbon-supported copper complex of 3,5-diamino-1,2,4-triazole as a cathode catalyst for alkaline fuel cell applications.

PubMed

Brushett, Fikile R; Thorum, Matthew S; Lioutas, Nicholas S; Naughton, Matthew S; Tornow, Claire; Jhong, Huei-Ru Molly; Gewirth, Andrew A; Kenis, Paul J A

2010-09-08

The performance of a novel carbon-supported copper complex of 3,5-diamino-1,2,4-triazole (Cu-tri/C) is investigated as a cathode material using an alkaline microfluidic H(2)/O(2) fuel cell. The absolute Cu-tri/C cathode performance is comparable to that of a Pt/C cathode. Furthermore, at a commercially relevant potential, the measured mass activity of an unoptimized Cu-tri/C-based cathode was significantly greater than that of similar Pt/C- and Ag/C-based cathodes. Accelerated cathode durability studies suggested multiple degradation regimes at various time scales. Further enhancements in performance and durability may be realized by optimizing catalyst and electrode preparation procedures.

[Coronary artery bypass surgery: methods of performance monitoring and quality control].

PubMed

Albert, A; Sergeant, P; Ennker, J

2009-10-01

The strength of coronary bypass operations depends on the preservation of their benefits regarding freedom of symptoms, quality of life and survival, over decades. Significant variability of the results of an operative intervention according to the hospital or the operating surgeon is considered a weakness in the procedure. The external quality insurance tries to reach a transparent service providing market through hospital ranking comparability. Widely available information and competition will promote the improvement of the whole quality. The structured dialog acts as a control instrument for the BQS (Federal Quality Insurance). It is launched in case of deviations from the standard references or statistically significant differences between the results of the operations in any hospital and the average notational results. In comparison to the external control the hospital internal control has greater ability to reach a medically useful statement regarding the results of the treatment and to correct the mistakes in time. An online information portal based on a departmental databank (DataWarehouse, DataMart) is an attractive solution for the physician in order to get transparently and timely informed about the variability in the performance.The individual surgeon significantly influences the short- and long-term treatment results. Accordingly, selection, targeted training and performance measurements are necessary.Strict risk management and failure analysis of individual cases are included in the methods of internal quality control aiming to identify and correct the inadequacies in the system and the course of treatment. According to the international as well as our own experience, at least 30% of the mortalities after bypass operations are avoidable. A functioning quality control is especially important in minimally invasive interventions because they are often technically more demanding in comparison to the conventional procedures. In the field of OPCAB surgery, the special advantages of the procedure can be utilised to reach a nearly complete avoidance of postoperative stroke through combining the procedure with aorta no-touch technique. The long-term success of the bypass operation depends on the type of bypass material in additions to many other factors. Both internal mammary arteries are considered the most durable.Using an operation preparation check contributes to the operative success.

One-pot synthesis of transition metal ion-chelating ordered mesoporous carbon/carbon nanotube composites for active and durable fuel cell catalysts

NASA Astrophysics Data System (ADS)

Dombrovskis, Johanna K.; Palmqvist, Anders E. C.

2017-07-01

Development of non-precious metal catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane (PEM) fuel cells with high activity and durability and with optimal water management properties is of outmost technological importance and highly challenging. Here we study the possibilities offered through judicious selection of small molecular precursors used for the formation of ordered mesoporous carbon-based non-precious metal ORR catalysts. By combining two complementary precursors, we present a one-pot synthesis that leads to a composite material consisting of transition metal ion-chelating ordered mesoporous carbon and multi-walled carbon nanotubes (TM-OMC/CNT). The resulting composite materials show high specific surface areas and a carbon structure that exhibits graphitic signatures. The synthesis procedure allows for tuning of the carbon structure, the surface area, the pore volume and the ratio of the two components of the composite. The TM-OMC/CNT composites were processed into membrane electrode assemblies and evaluated in single cell fuel cell measurements where they showed a combination of good ORR activity and very high durability.

Creating durable and esthetic gingival anatomy on a polyoxymethylene overdenture by using a chairside procedure.

PubMed

Login, Gary R

2017-07-01

Snap-On Smile (DenMat) appliances are tooth-borne overdentures used for a variety of temporary esthetic applications. However, their benefit can be limited in patients with high smile lines and altered gingival architecture because the teeth look too large. In this report, the author shows the chairside application of a silicone denture reline material used to recreate gingival anatomy on an overdenture fabricated from crystallized acetyl resin, the material used in a Snap-On Smile appliance. The author shows the gingival application's durability of greater than 2 years in a 78-year-old patient with multiple missing teeth and a severe mandibular ridge deformity. The author tested several commonly available denture reline materials and their bonding agents, which are known to bond to acrylic resin but have not been shown to bond to crystallized acetyl resin. The author observed no candida colonization during the 2-year reporting period. The author presents a simple and durable chairside technique to reproduce gingival tissue esthetically on Snap-On Smile appliances. Copyright © 2017 American Dental Association. Published by Elsevier Inc. All rights reserved.

Durability assessments of concrete using electrical properties and acoustic emission testing

NASA Astrophysics Data System (ADS)

Todak, Heather N.

Premature damage deterioration has been observed in pavement joints throughout the Midwestern region of the United States. Over time, severe joint damage creates a transportation safety concern and the necessary repairs can be an extreme economic burden. The deterioration is due in part to freeze-thaw damage associated with fluid accumulation at the pavement joints. This very preventable problem is an indication that current specifications and construction practices for freeze-thaw durability of concrete are inadequate. This thesis serves to create a better understanding of moisture ingress, freeze-thaw damage mechanisms, and the effect of variations in mixture properties on freeze-thaw behavior of concrete. The concepts of the nick point degree of saturation, sorptivity rates, and critical degree of saturation are discussed. These factors contribute to service life, defined in this study as the duration of time a concrete element remains below levels of critical saturation which are required for damage development to initiate. A theoretical model and a simple experimental procedure are introduced which help determine the nick point for a series of 32 concrete mixtures with unique mixture proportions and air entrainment properties. This simple experimental procedure is also presented as a method to measure important electrical properties in order to establish the formation factor, a valuable measure of concrete transport properties. The results of freeze-thaw testing with acoustic emission monitoring are presented to help understand and quantify damage development in concrete specimens when conditioned to various degrees of saturation. This procedure was used to study the relationship between air entrainment properties and the critical degree of saturation. Applying the concepts of degree of saturation and sorptivity, a performance-based model is proposed as a new approach to specifications for freeze-thaw durability. Finally, a conceptual model is presented to illustrate the effect of various changes in mixture proportions and air void properties on service life.

Building America Case Study: Measure Guideline: Guidance on Taped Insulating Sheathing Drainage Planes (Fact Sheet)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This guide provides information and recommendations to the following groups: Insulation contractors, General contractors, Builders, Home remodelers, Mechanical contractors, and Homeowners as a guide to the work that needs to be done. The order of work completed during home construction and retrofit improvements is important. Health and safety issues must be addressed first and are more important than durability issues. And durability issues are more important than saving energy. Not all techniques can apply to all houses. Special conditions will require special action. Some builders or homeowners will wish to do more than the important but basic retrofit strategies outlinedmore » by this guide. The following are best practice and product recommendations from the interviewed contractors and home builders who collectively have a vast amount of experience. Three significant items were discussed with the group which are required to make taped insulating sheathing a simple, long term, and durable drainage plane: 4. Horizontal joints should be limited or eliminated wherever possible 5. Where a horizontal joint exists use superior materials 6. Frequent installation inspection and regular trade training are required to maintain proper installation Section 5 of this measure guideline contains the detailed construction procedure for the three recommended methods to effectively seal the joints in exterior insulating sheathing to create a simple, long term, and durable drainage plane.« less

New types of time domain reflectometry sensing waveguides for bridge scour monitoring

NASA Astrophysics Data System (ADS)

Lin, Chih-Ping; Wang, Kai; Chung, Chih-Chung; Weng, Yu-Wen

2017-07-01

Scour is a major threat to bridge safety, especially in harsh fluvial environments. Real-time monitoring of bridge scour is still very limited due to the lack of robust and economic scour monitoring device. Time domain reflectometry (TDR) is an emerging waveguide-based technique holding great promise to develop more durable scour monitoring devices. This study presents new types of TDR sensing waveguides in forms of either sensing rod or sensing wire, taking into account of the measurement range, durability, and ease of field installation. The sensing rod is composed of a hollow grooved steel rod paired up with a metal strip on the insulating groove, while the sensing wire consists of two steel strands with one of them coated with an insulating jacket. The measurement sensitivity is inevitably sacrificed when other properties such as the measurement range, field durability, and installation easiness are enhanced. Factors affecting the measurement sensitivity were identified and experimentally evaluated for better arranging the waveguide conductors. A data reduction method for scour-depth estimation without the need for identifying the sediment/water reflection and a two-step calibration procedure for rating propagation velocities were proposed to work with the new types of TDR sensing waveguides. Both the calibration procedure and the data reduction method were experimentally validated. The test results indicated that the new TDR sensing waveguide provides accurate scour depth measurements regardless of the sacrificed sensitivity. The insulating coating of the new TDR sensing waveguide was also demonstrated to be effective in extending the measurement range up to at least 15 m.

Surgical treatment of obesity.

PubMed

Puzziferri, Nancy; Blankenship, Jeanne; Wolfe, Bruce M

2006-02-01

The surgical treatment of obesity has existed for over 50 yr. Surgical options have evolved from high-risk procedures infrequently performed, to safe, effective procedures increasingly performed. The operations used today provide significant durable weight loss, resolution or marked improvement of obesity-related comorbidities, and enhanced quality of life for the majority of patients. The effect of bariatric surgery on the neurohormonal regulation of energy homeostasis is not fully understood. Despite its effectiveness, less than 1% of obese patients are treated surgically. The perception that obesity surgery is unsafe remains a deterrent to care.

40 CFR Appendix Vii to Part 86 - Standard Bench Cycle (SBC)

Code of Federal Regulations, 2012 CFR

2012-07-01

.... VII Appendix VII to Part 86—Standard Bench Cycle (SBC) 1. The standard bench aging durability procedures [Ref. § 86.1823-08(d)] consist of aging a catalyst-oxygen-sensor system on an aging bench which follows the standard bench cycle (SBC) described in this appendix. 2. The SBC requires use of an aging...

40 CFR Appendix Vii to Part 86 - Standard Bench Cycle (SBC)

Code of Federal Regulations, 2014 CFR

2014-07-01

... VII to Part 86—Standard Bench Cycle (SBC) 1. The standard bench aging durability procedures [Ref. § 86.1823-08(d)] consist of aging a catalyst-oxygen-sensor system on an aging bench which follows the standard bench cycle (SBC) described in this appendix. 2. The SBC requires use of an aging bench with an...

40 CFR Appendix Vii to Part 86 - Standard Bench Cycle (SBC)

Code of Federal Regulations, 2013 CFR

2013-07-01

.... VII Appendix VII to Part 86—Standard Bench Cycle (SBC) 1. The standard bench aging durability procedures [Ref. § 86.1823-08(d)] consist of aging a catalyst-oxygen-sensor system on an aging bench which follows the standard bench cycle (SBC) described in this appendix. 2. The SBC requires use of an aging...

Durability of Hardboard Lap Siding

Treesearch

Charles Carll; Charles R. Boardman; Steve P. Verrill

2013-01-01

This paper describes a study that was undertaken to evaluate the degree of correlation between in-service performance of hardboard siding and its performance in the industry standard test procedure for “weatherability of substrate.” The study included 13 different hardboard sidings: 6 noncommercial boards and 7 commercial products. All manufacturing plants operating in...

19 CFR 24.13a - Car, compartment, and package seals; and fastenings; standards; acceptance by Customs.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 1 2011-04-01 2011-04-01 false Car, compartment, and package seals; and... PROCEDURE § 24.13a Car, compartment, and package seals; and fastenings; standards; acceptance by Customs. (a) General standards. The seals and fastenings, together, shall (1) Be strong and durable; (2) Be capable of...

40 CFR 1060.520 - How do I test fuel tanks for permeation emissions?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false How do I test fuel tanks for... STATIONARY EQUIPMENT Test Procedures § 1060.520 How do I test fuel tanks for permeation emissions? Measure...) Preconditioning durability testing. Take the following steps before an emission test, in any order, if your...

40 CFR 1060.520 - How do I test fuel tanks for permeation emissions?

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 34 2012-07-01 2012-07-01 false How do I test fuel tanks for... STATIONARY EQUIPMENT Test Procedures § 1060.520 How do I test fuel tanks for permeation emissions? Measure...) Preconditioning durability testing. Take the following steps before an emission test, in any order, if your...

40 CFR 1060.520 - How do I test fuel tanks for permeation emissions?

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 34 2013-07-01 2013-07-01 false How do I test fuel tanks for... STATIONARY EQUIPMENT Test Procedures § 1060.520 How do I test fuel tanks for permeation emissions? Measure...) Preconditioning durability testing. Take the following steps before an emission test, in any order, if your...

40 CFR 1060.520 - How do I test fuel tanks for permeation emissions?

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 33 2011-07-01 2011-07-01 false How do I test fuel tanks for... STATIONARY EQUIPMENT Test Procedures § 1060.520 How do I test fuel tanks for permeation emissions? Measure...) Preconditioning durability testing. Take the following steps before an emission test, in any order, if your...

40 CFR 1060.520 - How do I test fuel tanks for permeation emissions?

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 33 2014-07-01 2014-07-01 false How do I test fuel tanks for... STATIONARY EQUIPMENT Test Procedures § 1060.520 How do I test fuel tanks for permeation emissions? Measure...) Preconditioning durability testing. Take the following steps before an emission test, in any order, if your...

40 CFR 86.1823-08 - Durability demonstration procedures for exhaust emissions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) General Compliance Provisions for Control of Air Pollution From New and In... volume test groups may optionally meet the requirements of §§ 86.1838-01 and 86.1826-01 in lieu of the...

16 CFR 1201.4 - Test procedures.

Code of Federal Regulations, 2010 CFR

2010-01-01

... rigidity. (ii) The structural framing shall be welded or securely bolted at the corners and braced by one... figure 5 on this section. The bag shall be filled with No. 71/2 chilled lead shot to a total weight of... durability test equipment—(i) Boil test. Two containers of water shall be provided with means to maintain one...

16 CFR 1201.4 - Test procedures.

Code of Federal Regulations, 2012 CFR

2012-01-01

... rigidity. (ii) The structural framing shall be welded or securely bolted at the corners and braced by one... figure 5 on this section. The bag shall be filled with No. 71/2 chilled lead shot to a total weight of... durability test equipment—(i) Boil test. Two containers of water shall be provided with means to maintain one...

The Effect of Joint Control Training on the Acquisition and Durability of a Sequencing Task

ERIC Educational Resources Information Center

DeGraaf, Allison; Schlinger, Henry D., Jr.

2012-01-01

Gutierrez (2006) experimentally demonstrated the effects of joint control and particularly the role of response mediation in the sequencing behavior of adults using an unfamiliar language. The purpose of the current study was to replicate and extend the procedures used by Gutierrez by comparing the effects of joint control training with the…

The Sit-and-Wait Hypothesis in Bacterial Pathogens: A Theoretical Study of Durability and Virulence.

PubMed

Wang, Liang; Liu, Zhanzhong; Dai, Shiyun; Yan, Jiawei; Wise, Michael J

2017-01-01

The intriguing sit-and-wait hypothesis predicts that bacterial durability in the external environment is positively correlated with their virulence. Since its first proposal in 1987, the hypothesis has been spurring debates in terms of its validity in the field of bacterial virulence. As a special case of the vector-borne transmission versus virulence tradeoff, where vector is now replaced by environmental longevity, there are only sporadic studies over the last three decades showing that environmental durability is possibly linked with virulence. However, no systematic study of these works is currently available and epidemiological analysis has not been updated for the sit-and-wait hypothesis since the publication of Walther and Ewald's (2004) review. In this article, we put experimental evidence, epidemiological data and theoretical analysis together to support the sit-and-wait hypothesis. According to the epidemiological data in terms of gain and loss of virulence (+/-) and durability (+/-) phenotypes, we classify bacteria into four groups, which are: sit-and-wait pathogens (++), vector-borne pathogens (+-), obligate-intracellular bacteria (--), and free-living bacteria (-+). After that, we dive into the abundant bacterial proteomic data with the assistance of bioinformatics techniques in order to investigate the two factors at molecular level thanks to the fast development of high-throughput sequencing technology. Sequences of durability-related genes sourced from Gene Ontology and UniProt databases and virulence factors collected from Virulence Factor Database are used to search 20 corresponding bacterial proteomes in batch mode for homologous sequences via the HMMER software package. Statistical analysis only identified a modest, and not statistically significant correlation between mortality and survival time for eight non-vector-borne bacteria with sit-and-wait potentials. Meanwhile, through between-group comparisons, bacteria with higher host-mortality are significantly more durable in the external environment. The results of bioinformatics analysis correspond well with epidemiological data, that is, non-vector-borne pathogens with sit-and-wait potentials have higher number of virulence and durability genes compared with other bacterial groups. However, the conclusions are constrained by the relatively small bacterial sample size and non-standardized experimental data.

The Sit-and-Wait Hypothesis in Bacterial Pathogens: A Theoretical Study of Durability and Virulence

PubMed Central

Wang, Liang; Liu, Zhanzhong; Dai, Shiyun; Yan, Jiawei; Wise, Michael J.

2017-01-01

The intriguing sit-and-wait hypothesis predicts that bacterial durability in the external environment is positively correlated with their virulence. Since its first proposal in 1987, the hypothesis has been spurring debates in terms of its validity in the field of bacterial virulence. As a special case of the vector-borne transmission versus virulence tradeoff, where vector is now replaced by environmental longevity, there are only sporadic studies over the last three decades showing that environmental durability is possibly linked with virulence. However, no systematic study of these works is currently available and epidemiological analysis has not been updated for the sit-and-wait hypothesis since the publication of Walther and Ewald’s (2004) review. In this article, we put experimental evidence, epidemiological data and theoretical analysis together to support the sit-and-wait hypothesis. According to the epidemiological data in terms of gain and loss of virulence (+/-) and durability (+/-) phenotypes, we classify bacteria into four groups, which are: sit-and-wait pathogens (++), vector-borne pathogens (+-), obligate-intracellular bacteria (--), and free-living bacteria (-+). After that, we dive into the abundant bacterial proteomic data with the assistance of bioinformatics techniques in order to investigate the two factors at molecular level thanks to the fast development of high-throughput sequencing technology. Sequences of durability-related genes sourced from Gene Ontology and UniProt databases and virulence factors collected from Virulence Factor Database are used to search 20 corresponding bacterial proteomes in batch mode for homologous sequences via the HMMER software package. Statistical analysis only identified a modest, and not statistically significant correlation between mortality and survival time for eight non-vector-borne bacteria with sit-and-wait potentials. Meanwhile, through between-group comparisons, bacteria with higher host-mortality are significantly more durable in the external environment. The results of bioinformatics analysis correspond well with epidemiological data, that is, non-vector-borne pathogens with sit-and-wait potentials have higher number of virulence and durability genes compared with other bacterial groups. However, the conclusions are constrained by the relatively small bacterial sample size and non-standardized experimental data. PMID:29209284

Prediction of In-Space Durability of Protected Polymers Based on Ground Laboratory Thermal Energy Atomic Oxygen

NASA Technical Reports Server (NTRS)

Banks, Bruce A.; deGroh, Kim K.; Rutledge, Sharon; DiFilippo, Frank J.

1996-01-01

The probability of atomic oxygen reacting with polymeric materials is orders of magnitude lower at thermal energies (greater than O.1 eV) than at orbital impact energies (4.5 eV). As a result, absolute atomic oxygen fluxes at thermal energies must be orders of magnitude higher than orbital energy fluxes, to produce the same effective fluxes (or same oxidation rates) for polymers. These differences can cause highly pessimistic durability predictions for protected polymers and polymers which develop protective metal oxide surfaces as a result of oxidation if one does not make suitable calibrations. A comparison was conducted of undercut cavities below defect sites in protected polyimide Kapton samples flown on the Long Duration Exposure Facility (LDEF) with similar samples exposed in thermal energy oxygen plasma. The results of this comparison were used to quantify predicted material loss in space based on material loss in ground laboratory thermal energy plasma testing. A microindent hardness comparison of surface oxidation of a silicone flown on the Environmental Oxygen Interaction with Materials-III (EOIM-III) experiment with samples exposed in thermal energy plasmas was similarly used to calibrate the rate of oxidation of silicone in space relative to samples in thermal energy plasmas exposed to polyimide Kapton effective fluences.

Fabrication of durable copper plating superhydrophobic surface with improved corrosion resistance and oil-water separation properties

NASA Astrophysics Data System (ADS)

Zhao, Yichao; Xiao, Xinyan; Ye, Zhihao; Ji, Qiang; Xie, Wei

2018-02-01

A mechanical durable superhydrophobic copper-plated stainless steel mesh was successfully fabricated by an electrodeposition process and 1-octadecanethiol modification. The as-prepared superhydrophobic mesh displays water contact angle of 153° and shows excellent anti-corrosion and water-oil separation properties in the condition of 0.1 A/cm2 current density for 35 s. In comparison with bare stainless steel mesh, the corrosion current of the as-prepared superhydrophobic mesh is close to 1/6 of the former. Meanwhile, the as-prepared superhydrophobic mesh could continuously separate oil from oil-water mixtures. The separation efficiency of continuous separation is as high as 96% and shows less than 1% decrease after ten cycles.

Gastrointestinal metabolic surgery for the treatment of type 2 diabetes mellitus

PubMed Central

Pok, Eng-Hong; Lee, Wei-Jei

2014-01-01

Medical therapy for type 2 diabetes mellitus is ineffective in the long term due to the progressive nature of the disease, which requires increasing medication doses and polypharmacy. Conversely, bariatric surgery has emerged as a cost-effective strategy for obese diabetic individuals; it has low complication rates and results in durable weight loss, glycemic control and improvements in the quality of life, obesity-related co-morbidity and overall survival. The finding that glucose homeostasis can be achieved with a weight loss-independent mechanism immediately after bariatric surgery, especially gastric bypass, has led to the paradigm of metabolic surgery. However, the primary focus of metabolic surgery is the alteration of the physio-anatomy of the gastrointestinal tract to achieve glycemic control, metabolic control and cardio-metabolic risk reduction. To date, metabolic surgery is still not well defined, as it is used most frequently for less obese patients with poorly controlled diabetes. The mechanism of glycemic control is still incompletely understood. Published research findings on metabolic surgery are promising, but many aspects still need to be defined. This paper examines the proposed mechanism of diabetes remission, the efficacy of different types of metabolic procedures, the durability of glucose control, and the risks and complications associated with this procedure. We propose a tailored approach for the selection of the ideal metabolic procedure for different groups of patients, considering the indications and prognostic factors for diabetes remission. PMID:25339819

Damage Progression in Bolted Composites

NASA Technical Reports Server (NTRS)

Minnetyan, Levon; Chamis, Christos C.; Gotsis, Pascal K.

1998-01-01

Structural durability, damage tolerance, and progressive fracture characteristics of bolted graphite/epoxy composite laminates are evaluated via computational simulation. Constituent material properties and stress and strain limits are scaled up to the structure level to evaluate the overall damage and fracture propagation for bolted composites. Single and double bolted composite specimens with various widths and bolt spacings are evaluated. The effect of bolt spacing is investigated with regard to the structural durability of a bolted joint. Damage initiation, growth, accumulation, and propagation to fracture are included in the simulations. Results show the damage progression sequence and structural fracture resistance during different degradation stages. A procedure is outlined for the use of computational simulation data in the assessment of damage tolerance, determination of sensitive parameters affecting fracture, and interpretation of experimental results with insight for design decisions.

Damage Progression in Bolted Composites

NASA Technical Reports Server (NTRS)

Minnetyan, Levon; Chamis, Christos; Gotsis, Pascal K.

1998-01-01

Structural durability,damage tolerance,and progressive fracture characteristics of bolted graphite/epoxy composite laminates are evaluated via computational simulation. Constituent material properties and stress and strain limits are scaled up to the structure level to evaluate the overall damage and fracture propagation for bolted composites. Single and double bolted composite specimens with various widths and bolt spacings are evaluated. The effect of bolt spacing is investigated with regard to the structural durability of a bolted joint. Damage initiation, growth, accumulation, and propagation to fracture are included in the simulations. Results show the damage progression sequence and structural fracture resistance during different degradation stages. A procedure is outlined for the use of computational simulation data in the assessment of damage tolerance, determination of sensitive parameters affecting fracture, and interpretation of experimental results with insight for design decisions.

Durability of traditional plasters with respect to blast furnace slag-based plaster

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cerulli, T.; Pistolesi, C.; Maltese, C.

2003-09-01

Blast furnace slag is a residue of steel production. It is a latent hydraulic binder and is normally used to improve the durability of concrete and mortars. Slag could be also used as rendering mortar for masonry and old buildings. Today, cement and hydraulic lime are the most popular hydraulic binders used to make plasters. They are characterised by a low durability when exposed to the action of chemical and physical agents. The aim of this study was to provide a comparison between the physical-mechanical properties of some renders made with ordinary Portland cement, hydraulic lime, or slag. Furthermore, anmore » investigation was carried out to analyse mortar resistance to several aggressive conditions like acid attack, freezing and thawing cycles, abrasion, sulphate aggression, cycles in ultraviolet screening device, and salt diffusion. The specimens, after chemical attack, have been characterised from the chemical-physical [specific surface according to the BET (Brunauer-Emmet-Teller) method], crystal-chemical (X-ray diffraction, XRD), and morphological (scanning electron microscopy, SEM) points of view.« less

Durability of coconut shell powder (CSP) concrete

NASA Astrophysics Data System (ADS)

Leman, A. S.; Shahidan, S.; Senin, M. S.; Shamsuddin, S. M.; Anak Guntor, N. A.; Zuki, S. S. Mohd; Khalid, F. S.; Azhar, A. T. S.; Razak, N. H. S.

2017-11-01

The rising cost of construction in developing countries like Malaysia has led concrete experts to explore alternative materials such as coconut shells which are renewable and possess high potential to be used as construction material. Coconut shell powder in varying percentages of1%, 3% and 5% was used as filler material in concrete grade 30 and evaluated after a curing period of 7 days and 28days respectively. Compressive strength, water absorption and carbonation tests were conducted to evaluate the strength and durability of CSP concrete in comparison with normal concrete. The test results revealed that 1%, 3% and 5% of CSP concrete achieved a compressive strength of 47.65 MPa, 45.6 MPa and 40.55% respectively. The rate of water absorption of CSP concrete was recorded as 3.21%, 2.47%, and 2.73% for 1%, 3% and 5% of CSP concrete respectively. Although CSP contained a carbon composition of 47%, the carbonation test showed that CSP no signs of carbon were detected inside the concrete. To conclude, CSP offers great prospects as it demonstrated relatively high durability as a construction material.

Evaluation of Fine Aggregate Morphology by Image Method and Its Effect on Skid-Resistance of Micro-Surfacing.

PubMed

Xiao, Yue; Wang, Feng; Cui, Peide; Lei, Lei; Lin, Juntao; Yi, Mingwei

2018-05-29

Micro-surfacing is a widely used pavement preventive maintenance technology used all over the world, due to its advantages of fast construction, low maintenance cost, good waterproofness, and skid-resistance performance. This study evaluated the fine aggregate morphology and surface texture of micro-surfacing by AIMS (aggregate image measurement system), and explored the effect of aggregate morphology on skid-resistance of single-grade micro-surfacing. Sand patch test and British pendulum test were also used to detect skid-resistance for comparison with the image-based method. Wet abrasion test was used to measure skid-resistance durability for feasibility verification of single-grade micro-surfacing. The results show that the effect of Form2D on the skid-resistance of micro-surfacing is much stronger than that of angularity. Combining the feasibility analysis of durability and skid-resistance, 1.18⁻2.36 grade micro-surfacing meets the requirements of durability and skid-resistance at the same time. This study also determined that, compared with British pendulum test, the texture result obtained by sand patch test fits better with results of image method.

Assessment of structural valve deterioration of transcatheter aortic bioprosthetic balloon-expandable valves using the new European consensus definition.

PubMed

Eltchaninoff, Hélène; Durand, Eric; Avinée, Guillaume; Tron, Christophe; Litzler, Pierre-Yves; Bauer, Fabrice; Dacher, Jean-Nicolas; Werhlin, Camille; Bouhzam, Najime; Bettinger, Nicolas; Candolfi, Pascal; Cribier, Alain

2018-03-30

Durability of transcatheter aortic bioprosthetic valves remains a major issue. Standardised definitions of deterioration and failure of bioprosthetic valves have recently been proposed. The aim of this study was to assess structural transcatheter valve deterioration (SVD) and bioprosthetic valve failure (BVF) using these new definitions. All TAVI patients implanted up to September 2012 with a minimal theoretical five-year follow-up were included. Systematic clinical and echocardiographic follow-up was performed annually. New standardised definitions were used to assess durability of transcatheter aortic bioprosthetic valves. From 2002 to 2012, 378 patients were included. Mean age and logistic EuroSCORE were 83.3±6.8 years and 22.8±13.1%. Thirty-day mortality was 13.2%. Nine patients had SVD including two severe forms and two patients had definite late BVF. The incidence of SVD and BVF at eight years was 3.2% (95% CI: 1.45-6.11) and 0.58% (95% CI: 0.15-2.75), respectively. Even though limited by the poor survival of the very high-risk/compassionate early population, our data do not demonstrate any alarm concerning transcatheter aortic valve durability. Careful prospective assessment in younger and lower-risk patients and comparison with surgical bioprosthetic valves are required for further assessment of the long-term durability of transcatheter valves.

Volvo Penta 4.3 GL E15 Emissions and Durability Test

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zoubul, G.; Cahoon, M.; Kolb, R.

2011-10-01

A new Volvo Penta carbureted 4.3 GL engine underwent emissions and dynamometer durability testing from break-in to expected end of life using an accelerated ICOMIA marine emissions cycle and E15 fuel. Only ethanol content was controlled. All aging used splash-blended E15 fuel. Exhaust emissions, exhaust gas temperature, torque, power, barometric pressure, air temperature, and fuel flow were measured at five intervals using site-blended E15 aging fuel and certification fuel (E0). The durability test cycle showed no noticeable impact on mechanical durability or engine power. Emissions performance degraded beyond the certification limit for this engine family, mostly occurring by 28% ofmore » expected life. Such degradation is inconsistent with prior experience. Comparisons showed that E15 resulted in lower CO and HC, but increased NOX, as expected for non-feedback-controlled carbureted engines with increased oxygen in the fuel. Fuel consumption also increased with E15 compared with E0. Throughout testing, poor starting characteristics were exhibited on E15 fuel for hot re-start and cold-start. Cranking time to start and smooth idle was roughly doubled compared with typical E0 operation. The carburetor was factory-set for lean operation to ensure emissions compliance. Test protocols did not include carburetor adjustment to account for increased oxygen in the E15 fuel.« less

Durability of carbon fiber reinforced shape memory polymer composites in space

NASA Astrophysics Data System (ADS)

Jang, Joon Hyeok; Hong, Seok Bin; Ahn, Yong San; Kim, Jin-Gyun; Nam, Yong-Youn; Lee, Geun Ho; Yu, Woong-Ryeol

2016-04-01

Shape memory polymer (SMP) is one of smart polymers which exhibit shape memory effect upon external stimuli. Recently, shape memory polymer composites (SMPCs) have been considered for space structure instead of shape memory alloys due to their deformability, lightweight and large recovery ratio, requiring characterization of their mechanical properties against harsh space environment and further prediction of the durability of SMPCs in space. As such, the durability of carbon fiber reinforced shape memory polymer composites (CF-SMPCs) was investigated using accelerated testing method based on short-term testing of CF-SMPCs in harsh condition. CF-SMPCs were prepared using woven carbon fabrics and a thermoset SMP via vacuum assisted resin transfer molding process. Bending tests with constant strain rate of CF-SMPCs were conducted using universal tensile machine (UTM) and Storage modulus test were conducted using dynamic mechanical thermal analysis (DMTA). Using the results, a master curve based on time-temperature superposition principle was then constructed, through which the mechanical properties of CF-SMPCs at harsh temperature were predicted. CF-SMPCs would be exposed to simulated space environments under ultra-violet radiations at various temperatures. The mechanical properties including flexural and tensile strength and shape memory properties of SMPCs would be measured using UTM before and after such exposures for comparison. Finally, the durability of SMPCs in space would be assessed by developing a degradation model of SMPC.

Insight, working through, and practice: the role of procedural knowledge.

PubMed

Rosenblatt, Allan

2004-01-01

A conception of insight is proposed, based on a systems and information-processing framework and using current neuroscience concepts, as an integration of information that results in a new symbolization of experience with a significant change in self-image and a transformation of non-declarative procedural knowledge into declarative knowledge. Since procedural memory and knowledge, seen to include emotional and relationship issues, is slow to change, durable emotional and behavioral change often requires repeated practice, a need not explicitly addressed in standard psychoanalytic technique. Working through is thus seen as also encompassing nondynamic factors. The application of these ideas to therapeutic technique suggests possible therapeutic interventions beyond interpretation. An illustrative clinical vignette is presented.

Aortic Root Biomechanics After Sleeve and David Sparing Techniques: A Finite Element Analysis.

PubMed

Tasca, Giordano; Selmi, Matteo; Votta, Emiliano; Redaelli, Paola; Sturla, Francesco; Redaelli, Alberto; Gamba, Amando

2017-05-01

Aortic root aneurysm can be treated with valve-sparing procedures. The David and Yacoub techniques have shown excellent long-term results but are technically demanding. Recently, a new and simpler procedure, the Sleeve technique, was proposed with encouraging results. We aimed to quantify the biomechanics of the initially aneurysmal aortic root (AR) after the Sleeve procedure to assess whether it induces abnormal stresses, potentially undermining its durability. Two finite element (FE) models of the physiologic and aneurysmal AR were built, accounting for the anatomical asymmetry and the nonlinear and anisotropic mechanical properties of human AR tissues. On the aneurysmal model, the Sleeve and David techniques were simulated based on the corresponding published technical features. Aortic root biomechanics throughout 2 consecutive cardiac cycles were computed in each simulated configuration. Both sparing techniques restored physiologic-like kinematics of aortic valve (AV) leaflets but induced different leaflets stresses. The time course averaged over the leaflets' bellies was 35% higher in the David model than in the Sleeve model. Commissural stresses, which were equal to 153 and 318 kPa in the physiologic and aneurysmal models, respectively, became 369 and 208 kPa in the David and Sleeve models, respectively. No intrinsic structural problems were detected in the Sleeve model that might jeopardize the durability of the procedure. If corroborated by long-term clinical outcomes, the results obtained suggest that using this new technique could successfully simplify the surgical repair of AR aneurysms and reduce intraoperative complications. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Development of a procedure for forming assisted thermal joining of tubes

NASA Astrophysics Data System (ADS)

Chen, Hui; Löbbe, Christian; Staupendahl, Daniel; Tekkaya, A. Erman

2018-05-01

With the demand of lightweight design in the automotive industry, not only the wall-thicknesses of tubular components of the chassis or spaceframe are continuously decreased. Also the thicknesses of exhaust system parts are reduced to save material and mass. However, thinner tubular parts bring about additional challenges in joining. Welding or brazing methods, which are utilized in joining tubes with specific requirements concerning leak tightness, are sensitive to the gap between the joining partners. Furthermore, a large joining area is required to ensure the durability of the joint. The introduction of a forming step in the assembled state prior to thermal joining can define and control the gap for subsequent brazing or welding. The mechanical pre-joint resulting from the previously described calibration step also results in easier handling of the tubes prior to thermal joining. In the presented investigation, a spinning process is utilized to produce force-fit joints of varying lengths and diameter reduction and form-fit joints with varying geometrical attributes. The spinning process facilitates a high formability and geometrical flexibility, while at the achievable precision is high and the process forces are low. The strength of the joints is used to evaluate the joint quality. Finally, a comparison between joints produced by forming with subsequent brazing and original tube is conducted, which presents the high performance of the developed procedure for forming assisted thermal joining.

Atomic Oxygen Durability Testing of an International Space Station Solar Array Validation Coupon

NASA Technical Reports Server (NTRS)

Forkapa, Mark J.; Stidham, Curtis; Banks, Bruce A.; Rutledge, Sharon K.; Ma, David H.; Sechkar, Edward A.

1996-01-01

An International Space Station solar array validation coupon was exposed in a directed atomic oxygen beam for space environment durability testing at the NASA Lewis Research Center. Exposure to atomic oxygen and intermittent tensioning of the solar array were conducted to verify the solar array#s durability to low Earth orbital atomic oxygen and to the docking threat of plume loading both of which are anticipated over its expected mission life of fifteen years. The validation coupon was mounted on a specially designed rotisserie. The rotisserie mounting enabled the solar and anti-solar facing side of the array to be exposed to directed atomic oxygen in a sweeping arrival process replicating space exposure. The rotisserie mounting also enabled tensioning, in order to examine the durability of the array and its hinge to simulated plume loads. Flash testing to verify electrical performance of the solar array was performed with a solar simulator before and after the exposure to atomic oxygen and tensile loading. Results of the flash testing indicated little or no degradation in the solar array#s performance. Photographs were also taken of the array before and after the durability testing and are included along with comparisons and discussions in this report. The amount of atomic oxygen damage appeared minor with the exception of a very few isolated defects. There were also no indications that the simulated plume loadings had weakened or damaged the array, even though there was some erosion of Kapton due to atomic oxygen attack. Based on the results of this testing, it is apparent that the International Space Station#s solar arrays should survive the low Earth orbital atomic oxygen environment and docking threats which are anticipated over its expected mission life.

In vivo tissue response and durability of five novel synthetic polymers in a rabbit model.

PubMed

Sahin, E; Cingi, C; Eskiizmir, G; Altintoprak, N; Calli, A; Calli, C; Yilgör, I; Yilgör, E

2016-04-01

Alloplastic materials are frequently used in facial plastic surgeries such as rhinoplasty and nasal reconstruction. Unfortunately, the ideal alloplastic material has not been found. This experimental study evaluates the tissue response and durability of five novel polymers developed as an alloplastic material. In this experimental study involving a tertiary university hospital, six subcuticular pockets were formed at the back of 10 rabbits for the implantation of each polymer and sham group. Each pocket was excised with its adjacent tissue after three months, and collected for histopathological examination. Semi-quantitative examination including neovascularisation, inflammation, fibrosis, abscess formation, multinucleated foreign body giant cells was performed, and integrity of polymer was evaluated. A statistical comparison was performed. No statically significant difference was detected in neovascularisation, inflammation, fibrosis, abscess formation and multinucleated foreign body giant cells when a paired comparison between sham and polymer II, III and IV groups was performed individually. Nevertheless, the degree of fibrosis was less than sham group in polymer I (p = .027) and V (p = .018), although the other variables were almost similar. The integrity of polymers III (9 intact, 1 fragmented) and IV (8 intact, 2 absent) was better than the other polymers. These novel synthetic polymers could be considered as good candidates for clinical applicability. All polymers provided satisfactory results in terms of tissue response; however, fibrovascular integration was higher in polymers II, III and IV. In addition, the durability of polymer III and IV was better than the others. © Copyright by Società Italiana di Otorinolaringologia e Chirurgia Cervico-Facciale, Rome, Italy.

40 CFR 86.094-28 - Compliance with emission standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the outlier procedure and averaging (as allowed under § 86.094-26(a)(6)(i)) to the same data set, the...) through (3) of this section. (1) All valid exhaust emission data from the tests required under § 86.094-26... § 86.094-29 for all tests conducted on all durability data vehicles of the combination selected under...

40 CFR 86.094-28 - Compliance with emission standards.

Code of Federal Regulations, 2012 CFR

2012-07-01

... the outlier procedure and averaging (as allowed under § 86.094-26(a)(6)(i)) to the same data set, the...) through (3) of this section. (1) All valid exhaust emission data from the tests required under § 86.094-26... § 86.094-29 for all tests conducted on all durability data vehicles of the combination selected under...

40 CFR 86.094-28 - Compliance with emission standards.

Code of Federal Regulations, 2013 CFR

2013-07-01

... the outlier procedure and averaging (as allowed under § 86.094-26(a)(6)(i)) to the same data set, the...) through (3) of this section. (1) All valid exhaust emission data from the tests required under § 86.094-26... § 86.094-29 for all tests conducted on all durability data vehicles of the combination selected under...

40 CFR 86.094-28 - Compliance with emission standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the outlier procedure and averaging (as allowed under § 86.094-26(a)(6)(i)) to the same data set, the...) through (3) of this section. (1) All valid exhaust emission data from the tests required under § 86.094-26... § 86.094-29 for all tests conducted on all durability data vehicles of the combination selected under...

40 CFR Appendix Ix to Part 86 - Experimentally Determining the R-Factor for Bench Aging Durability Procedures

Code of Federal Regulations, 2014 CFR

2014-07-01

... catalyst. Calculate the least-squared best-fit line through the data. For the data set to be useful for this purpose the data should have an approximately common intercept between 0 and 4000 miles. See the... data between one- and two-times the standard. 2. Estimate the value of R and calculate the effective...

Failure mode prediction for composite structural insulated panels with MgO board facings

NASA Astrophysics Data System (ADS)

Smakosz, Łukasz; Kreja, Ireneusz

2018-01-01

Sandwich panels are readily used in civil engineering due to their high strength to weight ratio and the ease and speed of assembly. The idea of a sandwich section is to combine thin and durable facings with a light-weight core and the choice of materials used allows obtaining the desired behaviour. Panels in consideration consist of MgO (magnesium oxide) board facings and expanded polystyrene core and are characterized by immunity to biological corrosion, a high thermal insulation and a relatively low impact on environment. Customizing the range of panels to meet market needs requires frequent size changes, leading to different failure modes, which are identified in a series of costly full-scale laboratory tests. A nonlinear numerical model was created with a use of a commercial ABAQUS code and a user-defined procedure, which is able to reproduce observed failure mechanisms; its parameters were established on the basis of small-scale tests and numerical experiments. The model was validated by a comparison with the results of the full-scale bending and compression tests. The results obtained were in satisfactory agreement with the test data.

Management of tricuspid regurgitation

PubMed Central

Taramasso, Maurizio; Lapenna, Elisabetta; Alfieri, Ottavio

2014-01-01

Secondary tricuspid regurgitation is the most frequent type of tricuspid insufficiency in western countries. Its surgical treatment is still an object of debate both in terms of timing and surgical techniques. Until recently, the avoidance of surgery for tricuspid repair was commonly accepted in patients with less than severe secondary tricuspid regurgitation undergoing left-sided valve surgery. More recently, compelling evidence in favour of a more aggressive surgical approach in this setting has emerged. The surgical technique should be tailored to the stage of disease. Ring annuloplasty is more durable than suture annuloplasty and represents the method of choice in the presence of isolated annular dilatation. In patients in whom the dilatation of the tricuspid annulus is combined with significant leaflet tethering, annuloplasty alone is unlikely to be durable and additional procedures have been proposed in order to achieve a more durable repair. In this review, pathophysiology, surgical indications, techniques of repair and outcomes of secondary tricuspid regurgitation will be discussed. We will also focus on the challenging issue of significant tricuspid regurgitation occurring late after left-sided valve surgery. Finally, the current and future role of percutaneous tricuspid valve technologies will be briefly described. PMID:25184048

Report of the Dutch experience with the Ross procedure in 343 patients.

PubMed

Takkenberg, J J M; Dossche, K M E; Hazekamp, M G; Nijveld, A; Jansen, E W L; Waterbolk, T W; Bogers, A J J C

2002-07-01

Limited information is available on outcome after autograft aortic valve replacement, in particular with respect to the durability of the autograft and of the allograft used to reconstruct the right ventricular outflow tract. A retrospective follow-up study of all patients who underwent a Ross procedure in the Netherlands since 1988 was done to obtain an overview of the Dutch experience with this procedure. From 1988 to January 2000, 348 Ross procedures were performed in nine centers in the Netherlands. Pre-operative, peri-operative and follow-up data from 343 patients in seven centers (99% of all Dutch autograft patients) were collected and analyzed. Mean patient age was 26 years (SD 14, range 0-58) and male/female ratio was 2.1. Bicuspid valve or other congenital heart valve disease was the most common indication for operation. The root replacement technique was used in 95% of patients and concomitant procedures were done in 12%. Hospital mortality was 2.6% (N=9). Mean follow-up was 4 years (median 3.8, SD 2.8, range 0-12.5). Overall cumulative survival was 96% at 1 year (95% confidence interval (CI) 94-98%) and 94% at 5 and 7 post-operative years, respectively (95% CI 91-97%). At last follow-up, 87% of the surviving patients was in New York Heart Association (NYHA) class I. Independent predictors of overall mortality were pre-operative NYHA class IV/V and longer perfusion time. Autograft reoperation had to be performed in 14 patients and reintervention on the pulmonary allograft in 10 patients. Freedom from any valve-related reintervention was 88% at 7 years (95% CI 81-94%). The Dutch experience with the Ross procedure is favorable, with low operative mortality and good mid-term results. Although both the autograft in aortic position and the allograft in the right ventricular outflow tract have a limited durability, this has not yet resulted in considerable reoperation rates and associated morbidity and mortality.

Transcatheter aortic valve implantation: durability of clinical and hemodynamic outcomes beyond 3 years in a large patient cohort.

PubMed

Gurvitch, R; Wood, D A; Tay, E L; Leipsic, J; Ye, J; Lichtenstein, S V; Thompson, C R; Carere, R G; Wijesinghe, N; Nietlispach, F; Boone, R H; Lauck, S; Cheung, A; Webb, J G

2010-09-28

Although short- and medium-term outcomes after transcatheter aortic valve implantation are encouraging, long-term data on valve function and clinical outcomes are limited. Consecutive high-risk patients who had been declined as surgical candidates because of comorbidities but who underwent successful transcatheter aortic valve implantation with a balloon-expandable valve between January 2005 and December 2006 and survived past 30 days were assessed. Clinical, echocardiographic, and computed tomographic follow-up examinations were performed. Seventy patients who underwent successful procedures and survived longer than 30 days were evaluated at a minimum follow-up of 3 years. At a median follow-up of 3.7 years (interquartile range 3.4 to 4.3 years), survival was 57%. Survival at 1, 2, and 3 years was 81%, 74%, and 61%, respectively. Freedom from reoperation was 98.5% (1 patient with endocarditis). During this early procedural experience, 11 patients died within 30 days, and 8 procedures were unsuccessful. When these patients were included, overall survival was 51%. Transaortic pressure gradients increased from 10.0 mm Hg (interquartile range 8.0 to 12.0 mm Hg) immediately after the procedure to 12.1 mm Hg (interquartile range 8.6 to 16.0 mm Hg) after 3 years (P=0.03). Bioprosthetic valve area decreased from a mean of 1.7±0.4 cm(2) after the procedure to 1.4±0.3 cm(2) after 3 years (P<0.01). Aortic incompetence after implantation was trivial or mild in 84% of cases and remained unchanged or improved over time. There were no cases of structural valvular deterioration, stent fracture, deformation, or valve migration. Transcatheter aortic valve implantation demonstrates good medium- to long-term durability and preserved hemodynamic function, with no evidence of structural failure. The procedure appears to offer an adequate and lasting resolution of aortic stenosis in selected patients.

An Investigation of the Compatibility of Radiation and Convection Heat Flux Measurements

NASA Technical Reports Server (NTRS)

Liebert, Curt H.

1996-01-01

A method for determining time-resolved absorbed surface heat flux and surface temperature in radiation and convection environments is described. The method is useful for verification of aerodynamic, heat transfer and durability models. A practical heat flux gage fabrication procedure and a simple one-dimensional inverse heat conduction model and calculation procedure are incorporated in this method. The model provides an estimate of the temperature and heat flux gradient in the direction of heat transfer through the gage. This paper discusses several successful time-resolved tests of this method in hostile convective heating and cooling environments.

Peroral endoscopic myotomy: An emerging minimally invasive procedure for achalasia

PubMed Central

Vigneswaran, Yalini; Ujiki, Michael B

2015-01-01

Peroral endoscopic myotomy (POEM) is an emerging minimally invasive procedure for the treatment of achalasia. Due to the improvements in endoscopic technology and techniques, this procedure allows for submucosal tunneling to safely endoscopically create a myotomy across the hypertensive lower esophageal sphincter. In the hands of skilled operators and experienced centers, the most common complications of this procedure are related to insufflation and accumulation of gas in the chest and abdominal cavities with relatively low risks of devastating complications such as perforation or delayed bleeding. Several centers worldwide have demonstrated the feasibility of this procedure in not only early achalasia but also other indications such as redo myotomy, sigmoid esophagus and spastic esophagus. Short-term outcomes have showed great clinical efficacy comparable to laparoscopic Heller myotomy (LHM). Concerns related to postoperative gastroesophageal reflux remain, however several groups have demonstrated comparable clinical and objective measures of reflux to LHM. Although long-term outcomes are necessary to better understand durability of the procedure, POEM appears to be a promising new procedure. PMID:26468336

Transparent Metal-Salt-Filled Polymeric Radiation Shields

NASA Technical Reports Server (NTRS)

Edwards, David; Lennhoff, John; Harris, George

2003-01-01

"COR-RA" (colorless atomic oxygen resistant -- radiation shield) is the name of a transparent polymeric material filled with x-ray-absorbing salts of lead, bismuth, cesium, and thorium. COR-RA is suitable for use in shielding personnel against bremsstrahlung radiation from electron-beam welding and industrial and medical x-ray equipment. In comparison with lead-foil and leaded-glass shields that give equivalent protection against x-rays (see table), COR-RA shields are mechanically more durable. COR-RA absorbs not only x-rays but also neutrons and rays without adverse effects on optical or mechanical performance. The formulation of COR-RA with the most favorable mechanical-durability and optical properties contains 22 weight percent of bismuth to absorb x-rays, plus 45 atomic percent hydrogen for shielding against neutrons.

Monitoring the Durability Performance of Concrete in Nuclear Waste Containment. Technical Progress Report No. 4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ulm, Franz-Josef

2000-06-30

OAK-B135 Monitoring the Durability Performance of Concrete in Nuclear Waste Containment. Technical Progress Report No. 4. The analysis of the effect of cracks on the acceleration of the calcium leaching process of cement-based materials has been pursued. During the last period (Technical Progress Report No 3), we have introduced a modeling accounting for the high diffusivity of fractures in comparison with the weak solid material diffusivity. It has been shown through dimensional and asymptotic analysis that small fractures do not significantly accelerate the material aging process. This important result for the overall structural aging kinetics of containment structure has beenmore » developed in a paper submitted to the international journal ''Transport in Porous Media''.« less

Reinforcement of cement-based matrices with graphite nanomaterials

NASA Astrophysics Data System (ADS)

Sadiq, Muhammad Maqbool

Cement-based materials offer a desirable balance of compressive strength, moisture resistance, durability, economy and energy-efficiency; their tensile strength, fracture energy and durability in aggressive environments, however, could benefit from further improvements. An option for realizing some of these improvements involves introduction of discrete fibers into concrete. When compared with today's micro-scale (steel, polypropylene, glass, etc.) fibers, graphite nanomaterials (carbon nanotube, nanofiber and graphite nanoplatelet) offer superior geometric, mechanical and physical characteristics. Graphite nanomaterials would realize their reinforcement potential as far as they are thoroughly dispersed within cement-based matrices, and effectively bond to cement hydrates. The research reported herein developed non-covalent and covalent surface modification techniques to improve the dispersion and interfacial interactions of graphite nanomaterials in cement-based matrices with a dense and well graded micro-structure. The most successful approach involved polymer wrapping of nanomaterials for increasing the density of hydrophilic groups on the nanomaterial surface without causing any damage to the their structure. The nanomaterials were characterized using various spectrometry techniques, and SEM (Scanning Electron Microscopy). The graphite nanomaterials were dispersed via selected sonication procedures in the mixing water of the cement-based matrix; conventional mixing and sample preparation techniques were then employed to prepare the cement-based nanocomposite samples, which were subjected to steam curing. Comprehensive engineering and durability characteristics of cement-based nanocomposites were determined and their chemical composition, microstructure and failure mechanisms were also assessed through various spectrometry, thermogravimetry, electron microscopy and elemental analyses. Both functionalized and non-functionalized nanomaterials as well as different micro-scale fibers were used for comparison purposes at different volume fractions. Replicated mixes and tests were considered to provide the basis for statistically reliable inferences. Theoretical studies were conducted in order to develop insight into the reinforcement mechanisms of properly functionalized graphite nanomaterials. The results suggested that modified graphite nanomaterials improve the mechanical performance of cement-based matrices primarily through control of microcrack size and propagation, relying on their close spacing within matrix and dissipation of substantial energy by debonding and frictional pullout over their enormous surface areas. The gains in barrier qualities of cement-based materials with introduction of modified graphite nanomaterials could be attributed to the increased tortuosity of diffusion paths in the presence of closely spaced nanomaterials. Experimental investigations were designed and implemented towards identification of the optimum (nano- and micro-scale) reinforcement systems for high-performance concrete through RSA (Response Surface Analysis). A comprehensive experimental data base was developed on the mechanical, physical and durability characteristics as well as the structure and composition of high-performance cementitious nanocomposites reinforced with modified graphite nanomaterials and/ or different micro-fibers.

The Effect of Airborne Contaminants on Fuel Cell Performance and Durability

DOE Office of Scientific and Technical Information (OSTI.GOV)

St-Pierre, Jean; Pasaogullari, Ugur; Cheng, Tommy

The impact of contaminants on fuel cell performance was examined to document air filter specifications (prevention) and devise recovery procedures (maintenance) that are effective at the system level. Eight previously undocumented airborne contaminants were selected for detailed studies and characterization data was used to identify operating conditions that intensifying contamination effects. The use of many and complementary electrochemical, chemical and physical characterization methods and the derivation of several mathematical models supported the formulation of contamination mechanisms and the development of recovery procedures. The complexity of these contamination mechanisms suggests a shift to prevention and generic maintenance measures. Only two ofmore » the selected contaminants led to cell voltage losses after injection was interrupted. Proposed recovery procedures for calcium ions, a component of road de-icers, dessicants, fertilizers and soil conditioners, were either ineffective or partly effective, whereas for bromomethane, a fumigant, the cell voltage was recovered to its initial value before contamination by manipulating and sequencing operating conditions. However, implementation for a fuel cell stack and system remains to be demonstrated. Contamination mechanisms also led to the identification of membrane durability stressors. All 8 selected contaminants promote the formation of hydrogen peroxide, a known agent that can produce radicals that attack the ionomer and membrane molecular structure whereas the dehydrating effect of calcium ions on the ionomer and membrane increases their brittleness and favors the creation of pinholes under mechanical stresses. Data related to acetylene, acetonitrile and calcium ions are emphasized in the report.« less

JPRS Report, Science & Technology Europe

DTIC Science & Technology

1988-05-10

given environment essentially depends on three parameters ; these are: • the adhesion between the adhesive and the supports; • the cohesion of the...durability/CND J Electric current under high field/Tensile test at 4 degrees K I Synthetic hydroxyapatite /behavior under friction and wear GB NaCl, s...French programs GB Inventory of accelerated test procedures, correlation among parameters FC Influence of experimental parameters 8615 JPRS-EST-88

40 CFR Appendix Ix to Part 86 - Experimentally Determining the R-Factor for Bench Aging Durability Procedures

Code of Federal Regulations, 2013 CFR

2013-07-01

... for each catalyst. Calculate the least-squared best-fit line through the data. For the data set to be useful for this purpose the data should have an approximately common intercept between 0 and 4000 miles... testing yields data between one- and two-times the standard. 2. Estimate the value of R and calculate the...

40 CFR Appendix Ix to Part 86 - Experimentally Determining the R-Factor for Bench Aging Durability Procedures

Code of Federal Regulations, 2010 CFR

2010-07-01

... for each catalyst. Calculate the least-squared best-fit line through the data. For the data set to be useful for this purpose the data should have an approximately common intercept between 0 and 4000 miles... testing yields data between one- and two-times the standard. 2. Estimate the value of R and calculate the...

40 CFR Appendix Ix to Part 86 - Experimentally Determining the R-Factor for Bench Aging Durability Procedures

Code of Federal Regulations, 2011 CFR

2011-07-01

... for each catalyst. Calculate the least-squared best-fit line through the data. For the data set to be useful for this purpose the data should have an approximately common intercept between 0 and 4000 miles... testing yields data between one- and two-times the standard. 2. Estimate the value of R and calculate the...

40 CFR Appendix Ix to Part 86 - Experimentally Determining the R-Factor for Bench Aging Durability Procedures

Code of Federal Regulations, 2012 CFR

2012-07-01

... for each catalyst. Calculate the least-squared best-fit line through the data. For the data set to be useful for this purpose the data should have an approximately common intercept between 0 and 4000 miles... testing yields data between one- and two-times the standard. 2. Estimate the value of R and calculate the...

Cold Regions - Environmental Testing of Individual Soldier Clothing

DTIC Science & Technology

2011-10-17

Individual Soldier Clothing 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHORS 5d. PROJECT NUMBER 5e. TASK...This Test Operations Procedure (TOP) provides testing guidelines for individual Soldier cold weather clothing and footwear in a cold regions...Soldier clothing , along with its safety, reliability, durability, and performance when exposed to a cold regions environment. 15. SUBJECT TERMS

Evolutionary model of an anonymous consumer durable market

NASA Astrophysics Data System (ADS)

Kaldasch, Joachim

2011-07-01

An analytic model is presented that considers the evolution of a market of durable goods. The model suggests that after introduction goods spread always according to a Bass diffusion. However, this phase will be followed by a diffusion process for durable consumer goods governed by a variation-selection-reproduction mechanism and the growth dynamics can be described by a replicator equation. The theory suggests that products play the role of species in biological evolutionary models. It implies that the evolution of man-made products can be arranged into an evolutionary tree. The model suggests that each product can be characterized by its product fitness. The fitness space contains elements of both sites of the market, supply and demand. The unit sales of products with a higher product fitness compared to the mean fitness increase. Durables with a constant fitness advantage replace other goods according to a logistic law. The model predicts in particular that the mean price exhibits an exponential decrease over a long time period for durable goods. The evolutionary diffusion process is directly related to this price decline and is governed by Gompertz equation. Therefore it is denoted as Gompertz diffusion. Describing the aggregate sales as the sum of first, multiple and replacement purchase the product life cycle can be derived. Replacement purchase causes periodic variations of the sales determined by the finite lifetime of the good (Juglar cycles). The model suggests that both, Bass- and Gompertz diffusion may contribute to the product life cycle of a consumer durable. The theory contains the standard equilibrium view of a market as a special case. It depends on the time scale, whether an equilibrium or evolutionary description is more appropriate. The evolutionary framework is used to derive also the size, growth rate and price distribution of manufacturing business units. It predicts that the size distribution of the business units (products) is lognormal, while the growth rates exhibit a Laplace distribution. Large price deviations from the mean price are also governed by a Laplace distribution (fat tails). These results are in agreement with empirical findings. The explicit comparison of the time evolution of consumer durables with empirical investigations confirms the close relationship between price decline and Gompertz diffusion, while the product life cycle can be described qualitatively for a long time period.

Comparison of pore space textural characteristics of natural stone exposed to real weathering environment and/or subjected to accelerated weathering tests: implications for durability assessment

NASA Astrophysics Data System (ADS)

Prikryl, Richard; Weishauptová, Zuzana

2017-04-01

One of the key questions in the debate on durability of natural stone is related to the relevance of accelerated weathering tests for durability assessments, specifically whether similar material responses can be achieved? In the recent study, specimens of opuka stone (extremely fine-grained clayey-calcareous silicite) was subjected to accelerated weathering tests in a climatic chamber (sulphur dioxide atmosphere, freezing/thawing). After completion of certain number of cycles, pore space textural characteristics by means of mercury porosimetry were studied. These data were compared with porosimetric data obtained from a piece of stone, sampled from a carved stone altar located in the interior of the St. Vitus Cathedral (Prague, Czech Republic) which was affected by 150-years lasting indoor decay processes (cyclic themohygric stresses due to variable indoor atmospheric conditions). Interestingly, the pore space textural characteristics of these two sets of specimens are closely related and show some distinct features different from fresh, non-weathered material. Our observation therefore supports relevance of some accelerated weathering simulations; however, conditions of these simulations must be based on parameters of real environment.

Selection of labyrinth seals in steam turbines

NASA Astrophysics Data System (ADS)

Kostyuk, A. G.

2015-01-01

The efficiency, vibration stability, operational durability, and cost of the main types of peripheral seals used in steam turbines are considered. A comparison between the conventional and honeycomb seals is given. Conditions subject to which replacement of conventional seals by honeycomb ones can be justified are pointed out. The use of variable-pitch multicomb seals as the most promising ones is recommended.

Comparison of performance criteria for evaluating stake test data

Treesearch

Stan T. Lebow; Patricia K. Lebow; Grant T. Kirker

2017-01-01

Stake tests are a critical part of evaluating durability of wood in ground-contact, but there is a lack of criteria for interpreting stake test results. This paper discusses criteria that might be used to determine if short term ratings indicate satisfactory longterm performance. Ratings of 19 by 19 mm stakes from multiple plots in the Harrison Experimental Forest,...

The percutaneous trampoline platysmaplasty: technique and experience with 105 consecutive patients.

PubMed

Mueller, Gregory P; Leaf, Norman; Aston, Sherrell J; Stone, Corbett W

2012-01-01

Controversy persists regarding the optimal procedure to rejuvenate the aging neck. More invasive procedures carry increased risks of complications, whereas less invasive approaches may deliver marginal results. The challenge is selecting the appropriate procedure for delivering consistent, durable results meeting both the patient's and surgeon's expectations. The authors describe their trampoline platysmaplasty (TPP) approach, a percutaneous suture suspension necklift that constitutes a less invasive approach for neck rejuvenation. A retrospective study was conducted of 105 consecutive patients who underwent TPP. Age, sex, procedure(s) performed, complications, and patient satisfaction were recorded. Cadaver studies were conducted to compare the tensile strength of the ligaments that anchor the TPP to the tensile strength of the sutures placed to approximate the medial platysma borders. In addition, the accuracy of light transillumination to determine depth of travel of the light-emitting diode (LED) lighted rod was evaluated. Patients underwent either TPP alone (18 women, 24 men) or TPP with a facelift (35 women, 28 men) between October 2007 and June 2009. The average age of the patients was 52 years, and average length of follow-up was 33 months. Patient satisfaction was high. Three early patients underwent immediate revision to improve results secondary to the suture matrix being too loose. Six additional patients had recurrent banding around one year postoperatively, but correction was achieved in all six by replacing the matrix with the help of the lighted rod. The results of the cadaver study revealed that the tensile strength of the retaining ligaments was statistically identical to the medial platysma borders, and the light transillumination feedback was accurate with regard to the depth of travel of the illuminated rod tip. The TPP approach for neck rejuvenation is effective and durable in properly-selected patients. It works well as a stand-alone procedure and in conjunction with facelift procedures. It also offers younger patients a less-invasive option to improve neck contours inherited through genetics. After nearly three years of follow-up of the patients in this report, the results appear to be long-lasting.

Experimental study of physical properties of artificial materials for the development of the tissue-engineered valvular heart apparatus in comparison with biological analogs

NASA Astrophysics Data System (ADS)

Chiryatyeva, Aleksandra; Trebushat, Dmitry; Prokhorokhin, Aleksei; Khakhalkin, Vladimir; Andreev, Mark; Novokhreschenov, Aleksei; Kretov, Evgeny

2017-12-01

Cardiovascular diseases are the leading cause of death worldwide. Valvular heart disease often requires valve repair or replacement. Today, surgery uses xenograft—porcine or bovine pericardium. However, bioprosthetic valves do not ensure sufficient durability. We investigated 0.6% glutaraldehyde-treated porcine pericardium to define its properties. Using a tensile test stand, we studied characteristics of the polymeric material—expanded polytetrafluoroethylene (ePTFE)—and compared it to xenopericardium. The artificial material provides a better durability; it has higher elastic modulus and ultimate tensile strength. However, ePTFE samples demonstrated direction anisotropy due to extrusion features. It requires the enhancement of quality of the ePTFE sheet or investigation of other polymeric materials to find the adequate replacement for bioprosthetic heart valves.

A new specimen management system using RFID technology.

PubMed

Shim, Hun; Uh, Young; Lee, Seung Hwan; Yoon, Young Ro

2011-12-01

The specimen management system with barcode needs to be improved in order to solve inherent problems in work performance. This study describes the application of Radio Frequency Identification (RFID) which is the solution for the problems associated with specimen labeling and management. A new specimen management system and architecture with RFID technology for clinical laboratory was designed. The suggested system was tested in various conditions such as durability to temperature and aspect of effective utilization of new work flow under a virtual hospital clinical laboratory environment. This system demonstrates its potential application in clinical laboratories for improving work flow and specimen management. The suggested specimen management system with RFID technology has advantages in comparison to the traditional specimen management system with barcode in the aspect of mass specimen processing, robust durability of temperature, humidity changes, and effective specimen tracking.

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

NASA Technical Reports Server (NTRS)

Shin, Euy-Sik Eugene

2015-01-01

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

Bright and durable field emission source derived from refractory taylor cones

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirsch, Gregory

A method of producing field emitters having improved brightness and durability relying on the creation of a liquid Taylor cone from electrically conductive materials having high melting points. The method calls for melting the end of a wire substrate with a focused laser beam, while imposing a high positive potential on the material. The resulting molten Taylor cone is subsequently rapidly quenched by cessation of the laser power. Rapid quenching is facilitated in large part by radiative cooling, resulting in structures having characteristics closely matching that of the original liquid Taylor cone. Frozen Taylor cones thus obtained yield desirable tipmore » end forms for field emission sources in electron beam applications. Regeneration of the frozen Taylor cones in-situ is readily accomplished by repeating the initial formation procedures. The high temperature liquid Taylor cones can also be employed as bright ion sources with chemical elements previously considered impractical to implement.« less

Uterosacral ligament vaginal vault suspension: anatomy, outcome and surgical considerations.

PubMed

Yazdany, Taji; Bhatia, Narender

2008-10-01

With aging populations, primary pelvic organ and recurrent pelvic organ prolapse have become a large-scale public health concern. Surgical options for patients include both abdominal and vaginal approaches, each with its own safety and efficacy profiles. This review summarizes the most recent anatomic, surgical and outcome data for uterosacral ligament vault suspension. It offers data on methods to avoid complications and difficult surgical scenarios. Uterosacral ligament suspension allows reattachment of the vaginal vault high within the pelvis. New modifications in technique including the extraperitoneal and laparoscopic approaches allow surgeons more freedom when planning surgery. Five-year data on the durability of the procedure make it a viable surgical option. As a technique widely used by many pelvic reconstructive surgeons, uterosacral ligament vault suspension provides a safe, anatomically correct and durable approach to uterine and vault prolapse. It requires advanced surgical training and an intimate understanding of pelvic anatomy to avoid and identify ureteral injury.

Programming "loose training" as a strategy to facilitate language generalization.

PubMed Central

Campbell, C R; Stremel-Campbell, K

1982-01-01

This study investigated the generalization of spontaneous complex language behavior across a nontraining setting and the durability of generalization as a result of programming and "loose training" strategy. A within-subject, across-behaviors multiple-baseline design was used to examine the performance of two moderately retarded students in the use of is/are across three syntactic structures (i.e., "wh" questions, "yes/no" reversal questions, and statements). The language training procedure used in this study represented a functional example of programming "loose training." The procedure involved conducting concurrent language training within the context of an academic training task, and establishing a functional reduction in stimulus control by permitting the student to initiate a language response based on a wide array of naturally occurring stimulus events. Concurrent probes were conducted in the free play setting to assess the immediate generalization and the durability of the language behaviors. The results demonstrated that "loose training" was effective in establishing a specific set of language responses with the participants of this investigation. Further, both students demonstrated spontaneous use of the language behavior in the free play generalization setting and a trend was clearly evident for generalization to continue across time. Thus, the methods used appear to be successful for training the use of is/are in three syntactic structures. PMID:7118759

Evolution of Force Sensing Technologies.

PubMed

Shah, Dipen

2017-06-01

In order to Improve the procedural success and long-term outcomes of catheter ablation techniques for atrial fibrillation (AF), an Important unfulfilled requirement is to create durable electrophysiologically complete lesions. Measurement of contact force (CF) between the catheter tip and the target tissue can guide physicians to optimise both mapping and ablation procedures. Contact force can affect lesion size and clinical outcomes following catheter ablation of AF. Force sensing technologies have matured since their advent several years ago, and now allow the direct measurement of CF between the catheter tip and the target myocardium in real time. In order to obtain complete durable lesions, catheter tip spatial stability and stable contact force are important. Suboptimal energy delivery, lesion density/contiguity and/or excessive wall thickness of the pulmonary vein-left atrial (PV-LA) junction may result in conduction recovery at these sites. Lesion assessment tools may help predict and localise electrical weak points resulting in conduction recovery during and after ablation. There is increasing clinical evidence to show that optimal use of CF sensing during ablation can reduce acute PV re-conduction, although prospective randomised studies are desirable to confirm long-term favourable clinical outcomes. In combination with optimised lesion assessment tools, contact force sensing technology has the potential to become the standard of care for all patients undergoing AF catheter ablation.

Effect of a functional monomer (MDP) on the enamel bond durability of single-step self-etch adhesives.

PubMed

Tsuchiya, Kenji; Takamizawa, Toshiki; Barkmeier, Wayne W; Tsubota, Keishi; Tsujimoto, Akimasa; Berry, Thomas P; Erickson, Robert L; Latta, Mark A; Miyazaki, Masashi

2016-02-01

The present study aimed to determine the effect of the functional monomer, 10-methacryloxydecyl dihydrogen phosphate (MDP), on the enamel bond durability of single-step self-etch adhesives through integrating fatigue testing and long-term water storage. An MDP-containing self-etch adhesive, Clearfil Bond SE ONE (SE), and an experimental adhesive, MDP-free (MF), which comprised the same ingredients as SE apart from MDP, were used. Shear bond strength (SBS) and shear fatigue strength (SFS) were measured with or without phosphoric acid pre-etching. The specimens were stored in distilled water for 24 h, 6 months, or 1 yr. Although similar SBS and SFS values were obtained for SE with pre-etching and for MF after 24 h of storage in distilled water, SE with pre-etching showed higher SBS and SFS values than MF after storage in water for 6 months or 1 yr. Regardless of the pre-etching procedure, SE showed higher SBS and SFS values after 6 months of storage in distilled water than after 24 h or 1 yr. To conclude, MDP might play an important role in enhancing not only bond strength but also bond durability with respect to repeated subcritical loading after long-term water storage. © 2015 Eur J Oral Sci.

An improved glycerin-jelly mounting procedure for permanent preparations of helminth eggs.

PubMed

Kumagai, M; Inaba, T; Makioka, A; Ishiwata, K; Onishi, K; Watanabe, N

2010-04-01

Many attempts have been undertaken to make permanent preparations of helminth eggs. However, the resulting preparations either lacked durability or tended to deform thin-shelled eggs, such as those of the hookworm. To overcome these drawbacks, we have modified 2 aspects of the glycerin-jelly mounting procedure. First, we gradually changed the media in which the helminth eggs soaked, from 10% formalin via water to a 70% ethanol and 5% glycerin solution. It took 10 days, which is much longer than the time required for the processes previously reported. Second, we used a hole slide glass instead of a slide glass. Eggs of 11 species of helminths have been prepared with this procedure, and have kept their morphology without apparent change for more than 4 yr.

Effects of freeze-thaw on characteristics of new KMP binder stabilized Zn- and Pb-contaminated soils.

PubMed

Wei, Ming-Li; Du, Yan-Jun; Reddy, Krishna R; Wu, Hao-Liang

2015-12-01

For viable and sustainable reuse of solidified/stabilized heavy metal-contaminated soils as roadway subgrade materials, long-term durability of these soils should be ensured. A new binder, KMP, has been developed for solidifying/stabilizing soils contaminated with high concentrations of heavy metals. However, the effects of long-term extreme weather conditions including freeze and thaw on the leachability and strength of the KMP stabilized contaminated soils have not been investigated. This study presents a systematic investigation on the impacts of freeze-thaw cycle on leachability, strength, and microstructural characteristics of the KMP stabilized soils spiked with Zn and Pb individually and together. For comparison purpose, Portland cement is also tested as a conventional binder. Several series of tests are conducted including the toxicity characteristic leaching procedure (TCLP), modified European Community Bureau of Reference (BCR) sequential extraction procedure, unconfined compression test (UCT), and mercury intrusion porosimetry (MIP). The results demonstrate that the freeze-thaw cycles have much less impact on the leachability and strength of the KMP stabilized soils as compared to the PC stabilized soils. After the freeze-thaw cycle tests, the KMP stabilized soils display much lower leachability, mass loss, and strength loss. These results are assessed based on the chemical speciation of Zn and Pb, and pore size distribution of the soils. Overall, this study demonstrates that the KMP stabilized heavy metal-contaminated soils perform well under the freeze-thaw conditions.

Fluoroalkyl Siloxanes as Liquid-Repellent Fabric Finishes. Part 3. The Durability of the Copolymers and Comparisons with Commercially Available Finishes.

DTIC Science & Technology

1983-09-01

disponibles et on en a compare les resultats avec ceux qui ont 6ti obtenus dans le cas des finis expe’rimentaux. Les essais de durabilit englobaient...short sumary of these tests has been included in ref. 10. PHOSPHAIE RESISTANCE TESI The resistance of treated fabrics to wetting by organo-phosphorus

Effect of water repellent preservatives and other wood treatments on restoration and durability of millwork

Treesearch

R. Sam Williams

2001-01-01

This report describes the long-term performance of painted window units that were placed outdoors near Madison, Wisconsin, in 1956. Covered in this report are the effects of the initial water repellent preservative (WRP) treatment during the first 6 years of exposure, a comparison of the water repellent effectiveness (WRE) ofthe WRP with the condition of the windows...

Design for inadvertent damage in composite laminates

NASA Technical Reports Server (NTRS)

Singhal, Surendra N.; Chamis, Christos C.

1992-01-01

Simplified predictive methods and models to computationally simulate durability and damage in polymer matrix composite materials/structures are described. The models include (1) progressive fracture, (2) progressively damaged structural behavior, (3) progressive fracture in aggressive environments, (4) stress concentrations, and (5) impact resistance. Several examples are included to illustrate applications of the models and to identify significant parameters and sensitivities. Comparisons with limited experimental data are made.

Comparison of 3 biodegradable polymer and durable polymer-based drug-eluting stents in all-comers (BIO-RESORT): rationale and study design of the randomized TWENTE III multicenter trial.

PubMed

Lam, Ming Kai; Sen, Hanim; Tandjung, Kenneth; van Houwelingen, K Gert; de Vries, Arie G; Danse, Peter W; Schotborgh, Carl E; Scholte, Martijn; Löwik, Marije M; Linssen, Gerard C M; Ijzerman, Maarten J; van der Palen, Job; Doggen, Carine J M; von Birgelen, Clemens

2014-04-01

To evaluate the safety and efficacy of 2 novel drug-eluting stents (DES) with biodegradable polymer-based coatings versus a durable coating DES. BIO-RESORT is an investigator-initiated, prospective, patient-blinded, randomized multicenter trial in 3540 Dutch all-comers with various clinical syndromes, requiring percutaneous coronary interventions (PCI) with DES implantation. Randomization (stratified for diabetes mellitus) is being performed in a 1:1:1 ratio between ORSIRO sirolimus-eluting stent with circumferential biodegradable coating, SYNERGY everolimus-eluting stent with abluminal biodegradable coating, and RESOLUTE INTEGRITY zotarolimus-eluting stent with durable coating. The primary endpoint is the incidence of the composite endpoint target vessel failure at 1 year, consisting of cardiac death, target vessel-related myocardial infarction, or clinically driven target vessel revascularization. Power calculation assumes a target vessel failure rate of 8.5% with a 3.5% non-inferiority margin, giving the study a power of 85% (α level .025 adjusted for multiple testing). The impact of diabetes mellitus on post-PCI outcome will be evaluated. The first patient was enrolled on December 21, 2012. BIO-RESORT is a large, prospective, randomized, multicenter trial with three arms, comparing two DES with biodegradable coatings versus a reference DES with a durable coating in 3540 all-comers. The trial will provide novel insights into the clinical outcome of modern DES and will address the impact of known and so far undetected diabetes mellitus on post-PCI outcome. Copyright © 2014 The Authors. Published by Mosby, Inc. All rights reserved.

Ultrathin, bioresorbable polymer sirolimus-eluting stents versus thin, durable polymer everolimus-eluting stents in patients undergoing coronary revascularisation (BIOFLOW V): a randomised trial.

PubMed

Kandzari, David E; Mauri, Laura; Koolen, Jacques J; Massaro, Joseph M; Doros, Gheorghe; Garcia-Garcia, Hector M; Bennett, Johan; Roguin, Ariel; Gharib, Elie G; Cutlip, Donald E; Waksman, Ron

2017-10-21

The development of coronary drug-eluting stents has included use of new metal alloys, changes in stent architecture, and use of bioresorbable polymers. Whether these advancements improve clinical safety and efficacy has not been shown in previous randomised trials. We aimed to examine the clinical outcomes of a bioresorbable polymer sirolimus-eluting stent compared with a durable polymer everolimus-eluting stent in a broad patient population undergoing percutaneous coronary intervention. BIOFLOW V was an international, randomised trial done in patients undergoing elective and urgent percutaneous coronary intervention in 90 hospitals in 13 countries (Australia, Belgium, Canada, Denmark, Germany, Hungary, Israel, the Netherlands, New Zealand, South Korea, Spain, Switzerland, and the USA). Eligible patients were those aged 18 years or older with ischaemic heart disease undergoing planned stent implantation in de-novo, native coronary lesions. Patients were randomly assigned (2:1) to either an ultrathin strut (60 μm) bioresorbable polymer sirolimus-eluting stent or to a durable polymer everolimus-eluting stent. Randomisation was via a central web-based data capture system (mixed blocks of 3 and 6), and stratified by study site. The primary endpoint was 12-month target lesion failure. The primary non-inferiority comparison combined these data from two additional randomised trials of bioresorbable polymer sirolimus-eluting stent and durable polymer everolimus-eluting stent with Bayesian methods. Analysis was by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT02389946. Between May 8, 2015, and March 31, 2016, 4772 patients were recruited into the study. 1334 patients met inclusion criteria and were randomly assigned to treatment with bioresorbable polymer sirolimus-eluting stents (n=884) or durable polymer everolimus-eluting stents (n=450). 52 (6%) of 883 patients in the bioresorbable polymer sirolimus-eluting stent group and 41 (10%) of 427 patients in the durable polymer everolimus-eluting stent group met the 12-month primary endpoint of target lesion failure (95% CI -6·84 to -0·29, p=0·0399), with differences in target vessel myocardial infarction (39 [5%] of 831 patients vs 35 [8%] of 424 patients, p=0·0155). The posterior probability that the bioresorbable polymer sirolimus-eluting stent is non-inferior to the durable polymer everolimus-eluting stent was 100% (Bayesian analysis, difference in target lesion failure frequency -2·6% [95% credible interval -5·5 to 0·1], non-inferiority margin 3·85%, n=2208). The outperformance of the ultrathin, bioresorbable polymer sirolimus-eluting stent over the durable polymer everolimus-eluting stent in a complex patient population undergoing percutaneous coronary intervention suggests a new direction in improving next generation drug-eluting stent technology. BIOTRONIK. Copyright © 2017 Elsevier Ltd. All rights reserved.

Predictive Nomogram for the Durability of Pain Relief From Gamma Knife Radiation Surgery in the Treatment of Trigeminal Neuralgia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lucas, John T., E-mail: johnthomas75@gmail.com; Nida, Adrian M.; Isom, Scott

Purpose: To determine factors associated with the durability of stereotactic radiation surgery (SRS) for treatment of trigeminal neuralgia (TN). Methods and Materials: Between 1999 and 2008, 446 of 777 patients with TN underwent SRS and had evaluable follow-up in our electronic medical records and phone interview records. The median follow-up was 21.2 months. The Barrow Neurologic Institute (BNI) pain scale was used to determine pre- and post-SRS pain. Dose-volume anatomical measurements, Burchiel pain subtype, pain quality, prior procedures, and medication usage were included in this retrospective cohort to identify factors impacting the time to BNI 4-5 pain relapse by using Cox proportionalmore » hazard regression. An internet-based nomogram was constructed based on predictive factors of durable relief pre- and posttreatment at 6-month intervals. Results: Rates of freedom from BNI 4-5 failure at 1, 3, and 5 years were 84.5%, 70.4%, and 46.9%, respectively. Pain relief was BNI 1-3 at 1, 3, and 5 years in 86.1%, 74.3%, and 51.3% of type 1 patients; 79.3%, 46.2%, and 29.3% of type 2 patients; and 62.7%, 50.2%, and 25% of atypical facial pain patients. BNI type 1 pain score was achieved at 1, 3, and 5 years in 62.9%, 43.5%, and 22.0% of patients with type 1 pain and in 47.5%, 25.2%, and 9.2% of type 2 patients, respectively. Only 13% of patients with atypical facial pain achieved BNI 1 response; 42% of patients developed post-Gamma Knife radiation surgery (GKRS) trigeminal dysfunction. Multivariate analysis revealed that post-SRS numbness (hazard ratio [HR], 0.47; P<.0001), type 1 (vs type 2) TN (HR, 0.6; P=.02), and improved post-SRS BNI score at 6 months (HR, 0.009; P<.0001) were predictive of a durable pain response. Conclusions: The durability of SRS for TN depends on the presenting Burchiel pain type, the post-SRS BNI score, and the presence of post-SRS facial numbness. The durability of pain relief can be estimated pre- and posttreatment by using our nomogram for situations when the potential of relapse may guide the decision for initial intervention.« less

Comparison of Conventional Varnishes with Nanolacke UV Varnish With Respect to Hardness and Adhesion Durability

PubMed Central

Kaygin, Bulent; Akgun, Emre

2008-01-01

The long-term durability of varnished wooden surfaces used in either indoors or outdoors environments depends on the resistance of varnish layers on these surfaces against potential physical, mechanical and chemical effects to which they may be exposed. In this study, “Nanolacke ultraviolet varnish”, developed by a Turkish dying and varnish industry company and widely accepted as a 21st century technology has been compared to other conventional varnish systems widely used in the industry in terms of dry film resistance properties. In this study, cellulosic, polyurethane, polyester, synthetic and Nanolacke ultraviolet varnish have been applied on beech (Fagus orientalis L.) and oak (Quercus robur L.) wood samples which had been prepared according to the industry standards. Then, the hardness and adhesion resistance of these layers have been determined according to ASTM D 4366 and ASTM D 3359-2 standards, respectively. PMID:19325763

A new method for promoting adhesion between precious metal alloys and dental adhesives.

PubMed

Ohno, H; Araki, Y; Endo, K

1992-06-01

A new, simple method of modifying the adherend metal surface by a liquid Ga-Sn alloy (Adlloy) was applied to dental precious and base-metal alloys for adhesion with 4-META adhesive resin. Adhesions of 4-META resin to three other surface states--as-polished, oxidized at high temperature, and electroplated tin--were also performed for comparison with the adhesion on Adlloy-modified surfaces. Bond strength measurements were made, and the durability against water at the adhering interface was evaluated. The Adlloy-modified gold alloys (Type IV and 14 K) and silver-based alloys (Ag-Pd and Ag-Cu) showed not only high bond strengths but also excellent water durability at the adhesion interface. Surface modification by Adlloy, however, did not affect adhesion to Ag-In-Zn and base-metal (SUS, Co-Cr, and Ni-Cr) alloys. Adhesion to the tin-electroplated specimens was comparable with that to the Adlloy-modified specimens.

FEM Techniques for High Stress Detection in Accelerated Fatigue Simulation

NASA Astrophysics Data System (ADS)

Veltri, M.

2016-09-01

This work presents the theory and a numerical validation study in support to a novel method for a priori identification of fatigue critical regions, with the aim to accelerate durability design in large FEM problems. The investigation is placed in the context of modern full-body structural durability analysis, where a computationally intensive dynamic solution could be required to identify areas with potential for fatigue damage initiation. The early detection of fatigue critical areas can drive a simplification of the problem size, leading to sensible improvement in solution time and model handling while allowing processing of the critical areas in higher detail. The proposed technique is applied to a real life industrial case in a comparative assessment with established practices. Synthetic damage prediction quantification and visualization techniques allow for a quick and efficient comparison between methods, outlining potential application benefits and boundaries.

Bonding effectiveness to different chemically pre-treated dental zirconia.

PubMed

Inokoshi, Masanao; Poitevin, André; De Munck, Jan; Minakuchi, Shunsuke; Van Meerbeek, Bart

2014-09-01

The objective of this study was to evaluate the effect of different chemical pre-treatments on the bond durability to dental zirconia. Fully sintered IPS e.max ZirCAD (Ivoclar Vivadent) blocks were subjected to tribochemical silica sandblasting (CoJet, 3M ESPE). The zirconia samples were additionally pre-treated using one of four zirconia primers/adhesives (Clearfil Ceramic Primer, Kuraray Noritake; Monobond Plus, Ivoclar Vivadent; Scotchbond Universal, 3M ESPE; Z-PRIME Plus, Bisco). Finally, two identically pre-treated zirconia blocks were bonded together using composite cement (RelyX Ultimate, 3M ESPE). The specimens were trimmed at the interface to a cylindrical hourglass and stored in distilled water (7 days, 37 °C), after which they were randomly tested as is or subjected to mechanical ageing involving cyclic tensile stress (10 N, 10 Hz, 10,000 cycles). Subsequently, the micro-tensile bond strength was determined, and SEM fractographic analysis performed. Weibull analysis revealed the highest Weibull scale and shape parameters for the 'Clearfil Ceramic Primer/mechanical ageing' combination. Chemical pre-treatment of CoJet (3M ESPE) sandblasted zirconia using Clearfil Ceramic Primer (Kuraray Noritake) and Monobond Plus (Ivoclar Vivadent) revealed a significantly higher bond strength than when Scotchbond Universal (3M ESPE) and Z-PRIME Plus (Bisco) were used. After ageing, Clearfil Ceramic Primer (Kuraray Noritake) revealed the most stable bond durability. Combined mechanical/chemical pre-treatment, the latter with either Clearfil Ceramic Primer (Kuraray Noritake) or Monobond Plus (Ivoclar Vivadent), resulted in the most durable bond to zirconia. As a standard procedure to durably bond zirconia to tooth tissue, the application of a combined 10-methacryloyloxydecyl dihydrogen phosphate/silane ceramic primer to zirconia is clinically highly recommended.

Long-term micro-Deval durability of andesite aggregate

NASA Astrophysics Data System (ADS)

Czinder, Balázs; Török, Ákos

2017-04-01

Micro-Deval tests have been intensively used for analysing aggregate durability. The tests procedure described in details in the European Norm (EN 1097-1:2011). The current research intends to evaluate the long term durability of andesite aggregate by using extended micro-Deval tests. Andesite aggregate from Recsk (Hungary) was used for the tests. The tested andesite is a massive porphyritic biotite amphibol andesite that was formed during Eocene volcanism and forms a part of Mátra Mountains volcanic complex in NE Hungary. The aggregates were crushed and screened. Size fractions of 10.0/14.0 mm representing minimum and maximum grain sizes were used in the tests. 500 g of aggregate specimens were loaded in the steel drum and 2500 ml of water was added besides the 5000 g of steel balls into the device. The steel balls have a diameter of 10 mm according to EN. The test material - in the first stage - was subjected to 12,000 revolutions in the drum. This number is suggested by the EN. The micro-Deval coefficient was calculated after this first stage. Further wear of the andesitic material was tested by using additional revolutions. The increase in revolutions of the drum was in 12,000 rotation steps, reached 48,000 revolutions as a maximum. The tests were aimed to model the wear of aggregate on a longer term. It was also used to assess the durability of the aggregate when it is applied in engineering structures. The micro-Deval test results suggest that additional revolutions caused additional loss in material, i.e. increase in micro-Deval coefficient. A correlation is suggested between the revolution and andesite wear.

Stress Testing of the Philips 60W Replacement Lamp L Prize Entry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Poplawski, Michael E.; Ledbetter, Marc R.; Smith, Mark

2012-04-24

The Pacific Northwest National Laboratory, operated by Battelle for the U.S. Department of Energy, worked with Intertek to develop a procedure for stress testing medium screw-base light sources. This procedure, composed of alternating stress cycles and performance evaluation, was used to qualitatively compare and contrast the durability and reliability of the Philips 60W replacement lamp L Prize entry with market-proven compact fluorescent lamps (CFLs) with comparable light output and functionality. The stress cycles applied simultaneous combinations of electrical, thermal, vibration, and humidity stresses of increasing magnitude. Performance evaluations measured relative illuminance, x chromaticity and y chromaticity shifts after each stressmore » cycle. The Philips L Prize entry lamps appear to be appreciably more durable than the incumbent energy-efficient technology, as represented by the evaluated CFLs, and with respect to the applied stresses. Through the course of testing, all 15 CFL samples permanently ceased to function as a result of the applied stresses, while only 1 Philips L Prize entry lamp exhibited a failure, the nature of which was minor, non-destructive, and a consequence of a known (and resolved) subcontractor issue. Given that current CFL technology appears to be moderately mature and no Philips L Prize entry failures could be produced within the stress envelope causing 100 percent failure of the benchmark CFLs, it seems that, in this particular implementation, light-emitting diode (LED) technology would be much more durable in the field than current CFL technology. However, the Philips L Prize entry lamps used for testing were carefully designed and built for the competition, while the benchmark CFLs were mass produced for retail sale—a distinction that should be taken into consideration. Further reliability testing on final production samples would be necessary to judge the extent to which the results of this analysis apply to production versions of the Philips L Prize entry.« less

Endovascular stent-graft repair of failed endovascular abdominal aortic aneurysm repair.

PubMed

Baril, Donald T; Silverberg, Daniel; Ellozy, Sharif H; Carroccio, Alfio; Jacobs, Tikva S; Sachdev, Ulka; Teodorescu, Victoria J; Lookstein, Robert A; Marin, Michael L

2008-01-01

Despite high initial technical success, the long-term durability of endovascular abdominal aortic aneurysm repair (EVAR) continues to be a concern. Following EVAR, patients can experience endoleaks, device migration, device fractures, or aneurysm growth that may require intervention. The purpose of this study was to review all patients treated with secondary endovascular devices at our institution for failed EVAR procedures. Over an 8-year period, 988 patients underwent EVAR, of whom 42 (4.3%) required secondary interventions involving placement of additional endovascular devices. Data regarding patient characteristics, aneurysm size, initial device type, time until failure, failure etiology, secondary interventions, and outcomes were reviewed. The mean time from initial operation until second operation was 34.1 months. Failures included type I endoleaks in 38 patients (90.5%), type III endoleaks in two patients (4.8%), and enlarging aneurysms without definite endoleaks in two patients (4.8%). The overall technical success rate for secondary repair was 92.9% (39/42). Perioperative complications occurred in nine patients (21.4%), including wound complications (n = 6), cerebrovascular accident (CVA) (n = 1), foot drop (n = 1), and death (n = 1). Mean follow-up following secondary repair was 16.4 months (range 1-50). Eighty-six percent of patients treated with aortouni-iliac devices had successful repairs compared to 45% of patients treated with proximal cuffs. Ten patients (23.8%) had persistent or recurrent type I or type III endoleaks following revision. Of these, four had tertiary interventions, including two patients who had additional devices placed. Failures following EVAR occur in a small but significant number of patients. When anatomically possible, endovascular revision offers a safe means of treating these failures. Aortouni-iliac devices appear to offer a more durable repair than the proximal cuff for treatment of proximal type I endoleaks. Midterm results indicate that these patients may require additional procedures but have a low rate of aneurysm-related mortality. Longer-term follow-up is necessary to determine the durability of these endovascular revisions.

Pulmonary vein reconnection following catheter ablation of atrial fibrillation using the second-generation cryoballoon versus open-irrigated radiofrequency: results of a multicenter analysis.

PubMed

Aryana, Arash; Singh, Sheldon M; Mugnai, Giacomo; de Asmundis, Carlo; Kowalski, Marcin; Pujara, Deep K; Cohen, Andrew I; Singh, Steve K; Fuenzalida, Charles E; Prager, Nelson; Bowers, Mark R; O'Neill, Padraig Gearoid; Brugada, Pedro; d'Avila, André; Chierchia, Gian-Battista

2016-12-01

Catheter ablation of atrial fibrillation (CAAF) using the cryoballoon has emerged as an alternate strategy to point-by-point radiofrequency. However, there is little comparative data on long-term durability of pulmonary vein (PV) isolation comparing these two modalities. In this multicenter, retrospective analysis, the incidences/patterns of late PV reconnection following an index CAAF using the second-generation cryoballoon versus open-irrigated, non-force-sensing radiofrequency were examined. Of the 2002 patients who underwent a first-time CAAF, 186/1126 patients (16.5 %) ablated using cryoballoon and 174/876 patients (19.9 %) with non-contact force-guided radiofrequency required a repeat procedure at 11 ± 5 months. During follow-up, the incidence of atrial flutters/tachycardias was lower (19.9 vs. 32.8 %; p = 0.005) and fewer patients exhibited PV reconnection (47.3 vs. 60.9 %; p = 0.007) with cryoballoon versus radiofrequency. Additionally, fewer PVs had reconnected with cryoballoon versus radiofrequency (18.8 vs. 34.6 %; p < 0.001). With cryoballoon, the right inferior (p < 0.001) and left common (p = 0.039) PVs were more likely to exhibit late reconnection, versus the left superior PV with radiofrequency (p = 0.012). However, when comparing the two strategies, the left common PV was more likely to exhibit reconnection with cryoballoon, whereas all other PVs with the exception of the right inferior PV demonstrated a lower reconnection rate with cryoballoon versus radiofrequency. Lastly, in a logistic regression multivariate analysis, cryoballoon ablation and PV ablation time emerged as significant predictors of durable PV isolation at repeat procedure. In this large multicenter, retrospective analysis, CAAF using the second-generation cryoballoon was associated with improved durability of PV isolation compared to open-irrigated, non-force-sensing radiofrequency.

A prospective cross-sectional study of laparoscopic subtotal Lind fundoplication for gastro-oesophageal reflux disease--a durable and effective anti-reflux procedure.

PubMed

Shapey, I M; Agrawal, S; Peacock, A; Super, P

2015-01-01

Laparoscopic partial fundoplication for gastro-oesophageal reflux disease (GORD) is reported to have fewer side effects when compared to Nissen fundoplication, but doubts remain over its long term durability in controlling reflux. The aim of this study was to assess outcome of symptoms for all patients presenting with GORD undergoing routine laparoscopic subtotal Lind fundoplication. All patients undergoing laparoscopic fundoplication between August, 1999 and November, 2007 performed by a single surgeon were included in the study. The anti-reflux procedure studied was laparoscopic Lind (300°) fundoplication with crural repair in all cases. Patients completed pre and post-operative questionnaires containing validated scoring systems for heartburn, gas bloat, dysphagia and overall patient satisfaction. Over the 100-month period, 320 consecutive patients underwent laparoscopic subtotal Lind fundoplication. Of these, 256 (80%) replied to the questionnaire at a mean of 31 months (range 3-96 months) following surgery. 91.4% of respondents had an improvement in heartburn symptom score with a significant reduction in score from 7.74 preoperatively to 1.25 postoperatively (p<0.001). There was also a significant reduction of mean modified Visick score for reflux control (heartburn and regurgitation) from 3.49 preoperatively to 1.48 after surgery (p<0.001). In total, 22 patients developed recurrent reflux symptoms with half of these reporting their recurrence within two years following surgery. Because of this all were tested with post-operative pH testing, yet only one had a 24-h pH time outside the normal range. Overall patient satisfaction was high with a visual analogue score of 9 and 88% of the patients claimed they would have the operation again. Laparoscopic Lind fundoplication demonstrates excellent reflux control when performed routinely for all patients presenting with GORD. This technique is both durable and efficacious in controlling reflux symptoms. Copyright © 2014 Surgical Associates Ltd. Published by Elsevier Ltd. All rights reserved.

Valve-sparing aortic root replacement in patients with Marfan syndrome enrolled in the National Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions.

PubMed

Song, Howard K; Preiss, Liliana R; Maslen, Cheryl L; Kroner, Barbara; Devereux, Richard B; Roman, Mary J; Holmes, Kathryn W; Tolunay, H Eser; Desvigne-Nickens, Patrice; Asch, Federico M; Milewski, Rita K; Bavaria, Joseph; LeMaire, Scott A

2014-05-01

The long-term outcomes of aortic valve-sparing (AVS) root replacement in Marfan syndrome (MFS) patients remain uncertain. The study aim was to determine the utilization and outcomes of AVS root replacement in MFS patients enrolled in the Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Conditions (GenTAC). At the time of this analysis, 788 patients with MFS were enrolled in the GenTAC Registry, of whom 288 had undergone aortic root replacement. Patients who had undergone AVS procedures were compared to those who had undergone aortic valve replacement (AVR). AVS root replacement was performed in 43.5% of MFS patients, and the frequency of AVS was increased over the past five years. AVS patients were younger at the time of surgery (31.0 versus 36.3 years, p = 0.006) and more likely to have had elective rather than emergency surgery compared to AVR patients, in whom aortic valve dysfunction and aortic dissection was the more likely primary indication for surgery. After a mean follow up of 6.2 +/- 3.6 years, none of the 87 AVS patients had required reoperation; in contrast, after a mean follow up of 10.5 +/- 7.6 years, 11.5% of AVR patients required aortic root reoperation. Aortic valve function has been durable, with 95.8% of AVS patients having aortic insufficiency that was graded as mild or less. AVS root replacement is performed commonly among the MFS population, and the durability of the aortic repair and aortic valve function have been excellent to date. These results justify a continued use of the procedure in an elective setting. The GenTAC Registry will be a useful resource to assess the long-term durability of AVS root replacement in the future.

Efficacy and safety of a biodegradable polymer sirolimus-eluting stent in primary percutaneous coronary intervention: a randomized controlled trial

PubMed Central

Li, Qiang; Tong, Zichuan; Wang, Lefeng; Zhang, Jianjun; Ge, Yonggui; Wang, Hongshi; Li, Weiming; Xu, Li; Ni, Zhuhua

2013-01-01

Introduction With long-term follow-up, whether biodegradable polymer drug-eluting stents (DES) is efficient and safe in primary percutaneous coronary intervention (PCI) remains a controversial issue. This study aims to assess the long-term efficacy and safety of DES in PCI for ST-segment elevation myocardial infarction (STEMI). Material and methods A prospective, randomized single-blind study with 3-year follow-up was performed to compare biodegradable polymer DES with durable polymer DES in 332 STEMI patients treated with primary PCI. The primary end point was major adverse cardiac events (MACE) at 3 years after the procedure, defined as the composite of cardiac death, recurrent infarction, and target vessel revascularization. The secondary end points included in-segment late luminal loss (LLL) and binary restenosis at 9 months and cumulative stent thrombosis (ST) event rates up to 3 years. Results The rate of the primary end points and the secondary end points including major adverse cardiac events, in-segment late luminal loss, binary restenosis, and cumulative thrombotic event rates were comparable between biodegradable polymer DES and durable polymer DES in these 332 STEMI patients treated with primary PCI at 3 years. Conclusions Biodegradable polymer DES has similar efficacy and safety profiles at 3 years compared with durable polymer DES in STEMI patients treated with primary PCI. PMID:24482648

Fibrous composite material for textile heart valve design: in vitro assessment.

PubMed

Amri, Amna; Laroche, Gaetan; Chakfe, Nabil; Heim, Frederic

2018-04-17

With over 150,000 implantations performed over the world, transcatheter aortic valve replacement (TAVR) has become a surgical technique, which largely competes with open surgery valve replacement for an increasing number of patients. The success of the procedure favors the research toward synthetic valve leaflet materials as an alternative to biological tissues, whose durability remains unknown. In particular, fibrous constructions have recently proven to be durable in vivo over a 6-month period of time in animal sheep models. Exaggerated fibrotic tissue formation remains, however, a critical issue to be addressed. This work investigates the design of a composite fibrous construction combining a woven polyethylene terephthalate (PET) layer and a non-woven PET mat, which are expected to provide, respectively, strength and appropriate topography toward limited fibrotic tissue ingrowth. For this purpose, a specific equipment has been developed to produce non-woven PET mats made from fibers with small diameter. These mats were assembled with woven PET substrates using various assembling techniques in order to obtain hybrid fibrous constructions. The physical and mechanical properties of the obtained materials were assessed and valve samples were manufactured to be tested in vitro for hydrodynamic performances. The results show that the composite fibrous construction is characterized by properties suitable for the valve leaflet function, but the durability of the assembling is however limited under accelerated cyclic loading.

Technical Report for the Period 10 January 1959 to 30 June 1960

DTIC Science & Technology

1960-08-22

boon started to determine the efficacy of various drying procedures for polyesters. Water contents are being determined by the Karl Fischer method to an...CHARGES 17 XX.4 Inspection Methods 17 XXI SOLID PROPELLANTS FOR ROCKETS 18 XXI.1 Colloidal Propellants - Extruded 18 XXI.2 Colloidal Propellants - Cast...derivatives can be made more durable and, in particular, more resistant to heat. The method used has consisted in the preparation of crotonyl derivatives of

Transferable Durability: Enhancing decay resistance of non-durable species with extractives from durable wood species

Treesearch

G.T. Kirker; A.B. Blodgett; S. Lebow; C.A. Clausen

2013-01-01

Extractive content and composition is a vital component of naturally durable woods; however, variability in extractives can limit their usefulness in the field. Two extractive-free, non-durable wood species were pressure treated with ethanol-toluene extractives from 8 durable wood species. Extracted Southern pine, Paulownia and unextracted Southern pine blocks were...

Advanced Duct Sealing Testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sherman, Max H.; Walker, Iain S.

Duct leakage has been identified as a major source of energy loss in residential buildings. Most duct leakage occurs at the connections to registers, plenums or branches in the duct system. At each of these connections a method of sealing the duct system is required. Typical sealing methods include tapes or mastics applied around the joints in the system. Field examinations of duct systems have typically shown that these seals tend to fail over extended periods of time. The Lawrence Berkeley National Laboratory has been testing sealant durability for several years. Typical duct tape (i.e. fabric backed tapes with naturalmore » rubber adhesives) was found to fail more rapidly than all other duct sealants. This report summarizes the results of duct sealant durability testing of five UL 181B-FX listed duct tapes (three cloth tapes, a foil tape and an Oriented Polypropylene (OPP) tape). One of the cloth tapes was specifically developed in collaboration with a tape manufacturer to perform better in our durability testing. The first test involved the aging of common ''core-to-collar joints'' of flexible duct to sheet metal collars, and sheet metal ''collar-to-plenum joints'' pressurized with 200 F (93 C) air. The second test consisted of baking duct tape specimens in a constant 212 F (100 C) oven following the UL 181B-FX ''Temperature Test'' requirements. Additional tests were also performed on only two tapes using sheet metal collar-to-plenum joints. Since an unsealed flexible duct joint can have a variable leakage depending on the positioning of the flexible duct core, the durability of the flexible duct joints could not be based on the 10% of unsealed leakage criteria. Nevertheless, the leakage of the sealed specimens prior to testing could be considered as a basis for a failure criteria. Visual inspection was also documented throughout the tests. The flexible duct core-to-collar joints were inspected monthly, while the sheet metal collar-to-plenum joints were inspected weekly. The baking test specimens were visually inspected weekly, and the durability was judged by the observed deterioration in terms of brittleness, cracking, flaking and blistering (the terminology used in the UL 181B-FX test procedure).« less

Durability of a novel durable bait for control of subterranean termites (Isoptera: Rhinotermitidae): results of five-year field aging studies.

PubMed

Eger, J E; Hamm, R L; Demark, J J; Chin-Heady, E; Tolley, M P; Benson, E P; Zungoli, P A; Smith, M S; Spomer, N A

2014-06-01

A durable termite bait containing 0.5% noviflumuron was evaluated for physical durability, retention of active ingredient, consumption by termites, and toxicity to termites over 5 yr in field studies at locations in Indiana, Mississippi, and South Carolina. Plots in Indiana and Mississippi included both natural rainfall and irrigated plots, while plots in South Carolina received only natural rainfall. Samples collected every 3 mo for the first 4 yr were evaluated for consumption with a 7 d no-choice bioassay using Reticulitermes flavipes (Kollar). Consumption and toxicity of 5 yr samples were evaluated in similar bioassays conducted for 42 d. Durable baits received from field sites had some cracking, and a small amount of external flaking, but no major deterioration based on visual observation. There were no significant differences in noviflumuron concentration over the 5-yr period and no trend toward reduced concentrations of noviflumuron over time. Consumption of aged durable baits over 4 yr was variable, but termites usually consumed more aged durable bait than fresh durable bait and the differences were frequently significant. There were some exceptions, but termites consumed significantly more fresh durable bait than aged durable bait in only 4% of observations. When 5 yr samples were evaluated, consumption was lowest for fresh durable bait and termites consumed significantly more aged durable bait from irrigated plots in Indiana and from both natural and irrigated plots in Mississippi than fresh durable bait. Survival of termites fed blank durable bait was significantly higher than that for termites fed any of the baits containing noviflumuron and there were no significant differences in survival among the noviflumuron durable baits. Our results suggest that the bait would be durable for at least 5 yr and possibly longer under most environmental conditions.

Overview of existing cartilage repair technology.

PubMed

McNickle, Allison G; Provencher, Matthew T; Cole, Brian J

2008-12-01

Currently, autologous chondrocyte implantation and osteochondral grafting bridge the gap between palliation of cartilage injury and resurfacing via arthroplasty. Emerging technologies seek to advance first generation techniques and accomplish several goals including predictable outcomes, cost-effective technology, single-stage procedures, and creation of durable repair tissue. The biologic pipeline represents a variety of technologies including synthetics, scaffolds, cell therapy, and cell-infused matrices. Synthetic constructs, an alternative to biologic repair, resurface a focal chondral defect rather than the entire joint surface. Scaffolds are cell-free constructs designed as a biologic "net" to augment marrow stimulation techniques. Minced cartilage technology uses stabilized autologous or allogeneic fragments in 1-stage transplantation. Second and third generation cell-based methods include alternative membranes, chondrocyte seeding, and culturing onto scaffolds. Despite the promising early results of these products, significant technical obstacles remain along with unknown long-term durability. The vast array of developing technologies has exceptional promise and the potential to revolutionize the cartilage treatment algorithm within the next decade.

Progressive Fracture of Composite Structures

NASA Technical Reports Server (NTRS)

Minnetyan, Levon

2001-01-01

This report includes the results of a research in which the COmposite Durability STRuctural ANalysis (CODSTRAN) computational simulation capabilities were augmented and applied to various structures for demonstration of the new features and verification. The first chapter of this report provides an introduction to the computational simulation or virtual laboratory approach for the assessment of damage and fracture progression characteristics in composite structures. The second chapter outlines the details of the overall methodology used, including the failure criteria and the incremental/iterative loading procedure with the definitions of damage, fracture, and equilibrium states. The subsequent chapters each contain an augmented feature of the code and/or demonstration examples. All but one of the presented examples contains laminated composite structures with various fiber/matrix constituents. For each structure simulated, damage initiation and progression mechanisms are identified and the structural damage tolerance is quantified at various degradation stages. Many chapters contain the simulation of defective and defect free structures to evaluate the effects of existing defects on structural durability.

Box Isolation of Fibrotic Areas (BIFA): A Patient-Tailored Substrate Modification Approach for Ablation of Atrial Fibrillation.

PubMed

Kottkamp, Hans; Berg, Jan; Bender, Roderich; Rieger, Andreas; Schreiber, Doreen

2016-01-01

Catheter ablation strategies beyond pulmonary vein isolation (PVI) for treatment of atrial fibrillation (AF) are less well defined. Increasing clinical data indicate that atrial fibrosis is a critical common left atrial (LA) substrate in AF patients (pts). We applied a new substrate modification concept according to the individual fibrotic substrate as estimated from electroanatomic voltage mapping (EAVM) in 41 pts undergoing catheter ablation of AF. First, EAVM during sinus rhythm was done in redo cases of 10 pts with paroxysmal AF despite durable PVI. Confluent low-voltage areas (LVA) were found in all pts and were targeted with circumferential isolation, so-called box isolation of fibrotic areas (BIFA). This strategy led to stable sinus rhythm in 9/10 pts and was transferred prospectively to first procedures of 31 pts with nonparoxysmal AF. In 13 pts (42%), no LVA (<0.5 mV) were identified, and only PVI was performed. In 18 pts (58%), additional BIFA strategies were applied (posterior box in 5, anterior box in 7, posterior plus anterior box in 5, no box in 1 due to diffuse fibrosis). Mean follow-up was 12.5 ± 2.4 months. Single-procedure freedom from AF/atrial tachycardia was achieved in 72.2% of pts and in 83.3% of pts with 1.17 procedures/patient. In approximately 40% of pts with nonparoxysmal AF, no substantial LVA were identified, and PVI alone showed high success rate. In pts with paroxysmal AF despite durable PVI and in approximately 60% of pts with nonparoxysmal AF, individually localized LVA were identified and could be targeted successfully with the BIFA strategy. © 2015 Wiley Periodicals, Inc.

Economic impact of minimally invasive lumbar surgery.

PubMed

Hofstetter, Christoph P; Hofer, Anna S; Wang, Michael Y

2015-03-18

Cost effectiveness has been demonstrated for traditional lumbar discectomy, lumbar laminectomy as well as for instrumented and noninstrumented arthrodesis. While emerging evidence suggests that minimally invasive spine surgery reduces morbidity, duration of hospitalization, and accelerates return to activites of daily living, data regarding cost effectiveness of these novel techniques is limited. The current study analyzes all available data on minimally invasive techniques for lumbar discectomy, decompression, short-segment fusion and deformity surgery. In general, minimally invasive spine procedures appear to hold promise in quicker patient recovery times and earlier return to work. Thus, minimally invasive lumbar spine surgery appears to have the potential to be a cost-effective intervention. Moreover, novel less invasive procedures are less destabilizing and may therefore be utilized in certain indications that traditionally required arthrodesis procedures. However, there is a lack of studies analyzing the economic impact of minimally invasive spine surgery. Future studies are necessary to confirm the durability and further define indications for minimally invasive lumbar spine procedures.

Assessing the durability and efficiency of landscape-based strategies to deploy plant resistance to pathogens

PubMed Central

Rey, Jean-François; Barrett, Luke G.; Thrall, Peter H.

2018-01-01

Genetically-controlled plant resistance can reduce the damage caused by pathogens. However, pathogens have the ability to evolve and overcome such resistance. This often occurs quickly after resistance is deployed, resulting in significant crop losses and a continuing need to develop new resistant cultivars. To tackle this issue, several strategies have been proposed to constrain the evolution of pathogen populations and thus increase genetic resistance durability. These strategies mainly rely on varying different combinations of resistance sources across time (crop rotations) and space. The spatial scale of deployment can vary from multiple resistance sources occurring in a single cultivar (pyramiding), in different cultivars within the same field (cultivar mixtures) or in different fields (mosaics). However, experimental comparison of the efficiency (i.e. ability to reduce disease impact) and durability (i.e. ability to limit pathogen evolution and delay resistance breakdown) of landscape-scale deployment strategies presents major logistical challenges. Therefore, we developed a spatially explicit stochastic model able to assess the epidemiological and evolutionary outcomes of the four major deployment options described above, including both qualitative resistance (i.e. major genes) and quantitative resistance traits against several components of pathogen aggressiveness: infection rate, latent period duration, propagule production rate, and infectious period duration. This model, implemented in the R package landsepi, provides a new and useful tool to assess the performance of a wide range of deployment options, and helps investigate the effect of landscape, epidemiological and evolutionary parameters. This article describes the model and its parameterisation for rust diseases of cereal crops, caused by fungi of the genus Puccinia. To illustrate the model, we use it to assess the epidemiological and evolutionary potential of the combination of a major gene and different traits of quantitative resistance. The comparison of the four major deployment strategies described above will be the objective of future studies. PMID:29649208

31 CFR 240.17 - Powers of attorney.

Code of Federal Regulations, 2010 CFR

2010-07-01

... incompetent. (e) Springing durable special powers of attorney. A springing durable special power of attorney... principal's subsequent incompetence. As with a durable special power of attorney, a springing durable... than those specified in paragraph (b) of this section may be negotiated under a springing durable...

31 CFR 240.17 - Powers of attorney.

Code of Federal Regulations, 2014 CFR

2014-07-01

... incompetent. (e) Springing durable special powers of attorney. A springing durable special power of attorney... principal's subsequent incompetence. As with a durable special power of attorney, a springing durable... than those specified in paragraph (b) of this section may be negotiated under a springing durable...

Durability of Membrane Electrode Assemblies (MEAs) in PEM Fuel Cells Operated on Pure Hydrogen and Oxygen

NASA Technical Reports Server (NTRS)

Stanic, Vesna; Braun, James; Hoberecht, Mark

2003-01-01

Proton exchange membrane (PEM) fuel cells are energy sources that have the potential to replace alkaline fuel cells for space programs. Broad power ranges, high peak-to-nominal power capabilities, low maintenance costs, and the promise of increased life are the major advantages of PEM technology in comparison to alkaline technology. The probability of PEM fuel cells replacing alkaline fuel cells for space applications will increase if the promise of increased life is verified by achieving a minimum of 10,000 hours of operating life. Durability plays an important role in the process of evaluation and selection of MEAs for Teledyne s Phase I contract with the NASA Glenn Research Center entitled Proton Exchange Membrane Fuel cell (PEMFC) Power Plant Technology Development for 2nd Generation Reusable Launch Vehicles (RLVs). For this contract, MEAs that are typically used for H2/air operation were selected as potential candidates for H2/O2 PEM fuel cells because their catalysts have properties suitable for O2 operation. They were purchased from several well-established MEA manufacturers who are world leaders in the manufacturing of diverse products and have committed extensive resources in an attempt to develop and fully commercialize MEA technology. A total of twelve MEAs used in H2/air operation were initially identified from these manufacturers. Based on the manufacturers specifications, nine of these were selected for evaluation. Since 10,000 hours is almost equivalent to 14 months, it was not possible to perform continuous testing with each MEA selected during Phase I of the contract. Because of the lack of time, a screening test on each MEA was performed for 400 hours under accelerated test conditions. The major criterion for an MEA pass or fail of the screening test was the gas crossover rate. If the gas crossover rate was higher than the membrane intrinsic permeability after 400 hours of testing, it was considered that the MEA had failed the test. Three types of MEAs out of the nine total membranes failed the test. The evaluation results showed that fuel cell operating conditions (current, pressure, stoichiometric flow rates) were the parameters that influenced the durability of MEAs. In addition, the durability test results indicated that the type of membrane was also an important parameter for MEA durability. At accelerated test conditions, the MEAs with casted membranes failed during the 400 hour test. However, the MEAs prepared from the casted membrane with support as well as extruded membranes, both passed the 400h durability test at accelerated operating test conditions. As a result of the MEA accelerated durability tests, four MEAs were selected for further endurance testing. These tests are being carried out with four-cell stacks under nominal fuel cell operating conditions.

Evidence based abreactive ego state therapy for PTSD.

PubMed

Barabasz, Arreed

2013-07-01

A single 5-6 hours manualized abreactive ego state therapy session has recently been subjected to two placebo-controlled investigations meeting evidence-based criteria. Ego state therapy was found to be a highly effective and durable treatment for posttraumatic stress disorder. Apparently, ego state therapy works because it is emotion focused, activates sub-cortical structures, and because the supportive, interpretive therapist reconstructs the patient's personality to be resilient and adaptive. In this article the author reviews the treatment procedures and presents the findings of both studies.

Flexible palladium-based H2 sensor with fast response and low leakage detection by nanoimprint lithography.

PubMed

Lim, Su Hui; Radha, Boya; Chan, Jie Yong; Saifullah, Mohammad S M; Kulkarni, Giridhar U; Ho, Ghim Wei

2013-08-14

Flexible palladium-based H2 sensors have a great potential in advanced sensing applications, as they offer advantages such as light weight, space conservation, and mechanical durability. Despite these advantages, the paucity of such sensors is due to the fact that they are difficult to fabricate while maintaining excellent sensing performance. Here, we demonstrate, using direct nanoimprint lithography of palladium, the fabrication of a flexible, durable, and fast responsive H2 sensor that is capable of detecting H2 gas concentration as low as 50 ppm. High resolution and high throughput patterning of palladium gratings over a 2 cm × 1 cm area on a rigid substrate was achieved by heat-treating nanoimprinted palladium benzyl mercaptide at 250 °C for 1 h. The flexible and robust H2 sensing device was fabricated by subsequent transfer nanoimprinting of these gratings into a polycarbonate film at its glass transition temperature. This technique produces flexible H2 sensors with improved durability, sensitivity, and response time in comparison to palladium thin films. At ambient pressure and temperature, the device showed a fast response time of 18 s at a H2 concentration of 3500 ppm. At 50 ppm concentration, the response time was found to be 57 s. The flexibility of the sensor does not appear to compromise its performance.

Comparison between universal adhesives and two-step self-etch adhesives in terms of dentin bond fatigue durability in self-etch mode.

PubMed

Tsujimoto, Akimasa; Barkmeier, Wayne W; Takamizawa, Toshiki; Watanabe, Hidehiko; Johnson, William W; Latta, Mark A; Miyazaki, Masashi

2017-06-01

This aim of this study was to compare universal adhesives and two-step self-etch adhesives in terms of dentin bond fatigue durability in self-etch mode. Three universal adhesives - Clearfil Universal, G-Premio Bond, and Scotchbond Universal Adhesive - and three-two-step self-etch adhesives - Clearfil SE Bond, Clearfil SE Bond 2, and OptiBond XTR - were used. The initial shear bond strength and shear fatigue strength of resin composite bonded to adhesive on dentin in self-etch mode were determined. Scanning electron microscopy observations of fracture surfaces after bond strength tests were also made. The initial shear bond strength of universal adhesives was material dependent, unlike that of two-step self-etch adhesives. The shear fatigue strength of Scotchbond Universal Adhesive was not significantly different from that of two-step self-etch adhesives, unlike the other universal adhesives. The shear fatigue strength of universal adhesives differed depending on the type of adhesive, unlike those of two-step self-etch adhesives. The results of this study encourage the continued use of two-step self-etch adhesive over some universal adhesives but suggest that changes to the composition of universal adhesives may lead to a dentin bond fatigue durability similar to that of two-step self-etch adhesives. © 2017 Eur J Oral Sci.

Comparison of enamel bond fatigue durability of universal adhesives and two-step self-etch adhesives in self-etch mode.

PubMed

Tsujimoto, Akimasa; Barkmeier, Wayne W; Hosoya, Yumiko; Nojiri, Kie; Nagura, Yuko; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

2017-10-01

To comparatively evaluate universal adhesives and two-step self-etch adhesives for enamel bond fatigue durability in self-etch mode. Three universal adhesives (Clearfil Universal Bond; G-Premio Bond; Scotchbond Universal Adhesive) and three two-step self-etch adhesives (Clearfil SE Bond; Clearfil SE Bond 2; OptiBond XTR) were used. The initial shear bond strength and shear fatigue strength of the adhesive to enamel in self-etch mode were determined. The initial shear bond strengths of the universal adhesives to enamel in self-etch mode was significantly lower than those of two-step self-etch adhesives and initial shear bond strengths were not influenced by type of adhesive in each adhesive category. The shear fatigue strengths of universal adhesives to enamel in self-etch mode were significantly lower than that of Clearfil SE Bond and Clearfil SE Bond 2, but similar to that OptiBond XTR. Unlike two-step self-etch adhesives, the initial shear bond strength and shear fatigue strength of universal adhesives to enamel in self-etch mode was not influenced by the type of adhesive. This laboratory study showed that the enamel bond fatigue durability of universal adhesives was lower than Clearfil SE Bond and Clearfil SE Bond 2, similar to Optibond XTR, and was not influenced by type of adhesive, unlike two-step self-etch adhesives.

Medium-Term Results of Laparoscopic Sleeve Gastrectomy: a Matched Comparison with Gastric Bypass.

PubMed

Lee, Wei-Jei; Pok, Eng-Hong; Almulaifi, Abdullah; Tsou, Ju Juin; Ser, Kong-Han; Lee, Yi-Chih

2015-08-01

Laparoscopic sleeve gastrectomy (LSG) is considered a primary bariatric surgery and is increasingly being performed worldwide; however, long-term data regarding the durability of this procedure are inadequate. Here, we report the long-term results of LSGs in comparison to those of gastric bypass surgeries. A prospectively collected bariatric database from Ming-Shen General Hospital was retrospectively studied. Five hundred nineteen morbidly obese patients (mean age 36.0 ± 9.1 years old (14-71), 74.6 % female, mean body mass index (BMI) 37.5 ± 6.1 kg/m(2)) underwent LSG as a primary bariatric procedure from 2006 to 2012 at our institute. The operative parameters, weight loss, laboratory data, and quality of life were followed. Another two matched groups of laparoscopic Roux-en-Y gastric bypass (RYGB) and laparoscopic single anastomosis (mini-) gastric bypass (SAGB) patients who were matched in terms of age, sex, and BMI were recruited for comparisons. The mean surgical time for LSG was 113.5 ± 31.3 min, and the mean blood loss was 49.1 + 100.9 ml. The rate of major complications was 1.6 %, and the average length of the postoperative stay was 3.0 ± 1.7 days. The operation times of the RYGB patients were longer than those of both the LSG and SAGB patients. The RYGB and SAGB patients experienced higher major complication rate than the LSG patients. The weight loss of the LSG patient at 5 years was 28.3 + 8.9 %, and the mean BMI was 27.1 + 4.3. The RYGB patients exhibited a 5-year weight loss similar to the LSG patients, and the SAGB patients exhibited greater weight loss than both of the other groups. Both the RYGB and SAGB patients exhibited significantly better glycemic control and lower blood lipids than the LSG patients, but the LSG patients exhibited a lesser micronutrient deficiency than the RYGB and SAGB groups. All three of the groups exhibited improved quality of life at 5 years after surgery, and there was no significant between-group difference in this measure. LSG appears to be an ideal bariatric surgery, and the efficacy of this surgery is not inferior to that of gastric bypass.

First-Order SPICE Modeling of Extreme-Temperature 4H-SiC JFET Integrated Circuits

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.; Spry, David J.; Chen, Liang-Yu

2016-01-01

A separate submission to this conference reports that 4H-SiC Junction Field Effect Transistor (JFET) digital and analog Integrated Circuits (ICs) with two levels of metal interconnect have reproducibly demonstrated electrical operation at 500 C in excess of 1000 hours. While this progress expands the complexity and durability envelope of high temperature ICs, one important area for further technology maturation is the development of reasonably accurate and accessible computer-aided modeling and simulation tools for circuit design of these ICs. Towards this end, we report on development and verification of 25 C to 500 C SPICE simulation models of first order accuracy for this extreme-temperature durable 4H-SiC JFET IC technology. For maximum availability, the JFET IC modeling is implemented using the baseline-version SPICE NMOS LEVEL 1 model that is common to other variations of SPICE software and importantly includes the body-bias effect. The first-order accuracy of these device models is verified by direct comparison with measured experimental device characteristics.

Spectroscopic comparison of effects of electron radiation on mechanical properties of two polyimides

NASA Technical Reports Server (NTRS)

Long, Edward R., Jr.; Long, Sheila Ann T.

1987-01-01

The differences in the radiation durabilities of two polyimide materials, Du Pont Kapton and General Electric Ultem, are compared. An explanation of the basic mechanisms which occur during exposure to electron radiation from analyses of infrared (IR) and electron paramagnetic resonance (EPR) spectroscopic data for each material is provided. The molecular model for Kapton was, in part, established from earlier modeling for Ultem (pp. 1293-1298 of IEEE Transactions on Nuclear Science, December 1984). Techniques for understanding the durability of one complex polymer based on the understanding of a different and equally complex polymer are demonstrated. The spectroscopic data showed that the primary radiation-generated change in the tensile properties of Ultem (a large reduction in tensile elongation) was due to crosslinking, which followed the capture by phenyl radicals of hydrogen atoms removed from gem-dimethyl groups. In contrast, the tensile properties of Kapton remained unchanged because radical-radical recombination, a self-mending process, took place.

Analysis of reverse martensitic transformation of prehardened 16XCH steel

NASA Astrophysics Data System (ADS)

Muravyev, Vasily; Frolov, Alexey; Lonchakov, Sergey; Bakhmatov, Pavel

2015-10-01

In the paper the structural evolution of previously tempered 16XCH steel is investigated. The influence of temperature and time conditions of heating on temperature of austenization is revealed and the influence of structural changes on steel properties is defined. The analysis of the obtained results showed an increase of plasticity at the initial stage of reverse martensitic transformation and an increase of plasticity at increased durability. It is experimentally found that reverse transformation of packet and lath martensite into the initial phase (holding for a fraction of a second, temperature 400-450°C) leads to a sharp, more than 2-fold, reduction of strength and increase of plasticity. The effect of increased plasticity under reverse martensitic transformation conditions is observed. The structure of packet and lath martensite is more fine-grained in comparison with initial quenching; the durability and plasticity are much higher. Despite the derived results, the revealed effects of increased plasticity and strength require further exploration to increase the reliability of constructions made of low-alloyed steels.

Reactive powder based concretes: Mechanical properties, durability and hybrid use with OPC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cwirzen, A.; Penttala, V.; Vornanen, C.

2008-10-15

The basic mechanical properties, frost durability and the bond strength with normal strength concretes of the ultra high strength (UHS) mortars and concretes were studied. The produced mixes had plastic or fluid-like consistency. The 28-day compressive strength varied between 170 and 202 MPa for the heat-treated specimens and between 130 and 150 MPa for the non-heat-treated specimens. The shrinkage values were two times higher for the UHS mortars in comparison with the UHS concretes. After the initial shrinkage, swelling was noticed in the UHS mortars. The lowest creep values were measured for the non-heat-treated UHS concretes. The frost-deicing salts durabilitymore » of the UHS mortars and concretes appeared to be very good even despite the increased water uptake of the UHS concretes. The study of the hybrid concrete beams indicated the formation of low strength transition zone between the UHS mortar and normal strength concrete.« less

The Role of Biomass Composition and Steam Treatment on Durability of Pellets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Yong; Chandra, Richard P.; Sokhansanj, Shahab

Steam treatment has been reported to improve the durability of wood pellet likely by changing the physical and chemical structures of wood particles, but published literature is inconclusive about which structure change is the major reason for enhanced durability. Here, in this paper, steam treatment was combined either with alkaline or with SO 2 to study. The solids obtained after steam treatments along with a control sample were dried and each was compacted into pellets. The pellets were then tested for durability. Steam treatment alone dominated improvements in durability. The pellet durability increased with the amount of xylose, but xylosemore » performed better in the pellet from raw poplar than did in the pellet from treated poplar. Water-soluble components contributed a maximum 4% of the durability of poplar pellets. The addition of lignin and sugars to substrates after steam treatment did not improve durability significantly. The surface modification that took place as a result of size reduction during steam treatment was the major reason, contributing about 50% of the durability of the pellet from steam-treated poplar. The acidity of steam treatment slightly affected the relative contributions of these structure changes on the durability. Lastly, the new knowledge helps tailor the chemical and/or mechanical pretreatment involved in pelleting biomass to durable pellets.« less

The Role of Biomass Composition and Steam Treatment on Durability of Pellets

DOE PAGES

Tang, Yong; Chandra, Richard P.; Sokhansanj, Shahab; ...

2018-03-03

Steam treatment has been reported to improve the durability of wood pellet likely by changing the physical and chemical structures of wood particles, but published literature is inconclusive about which structure change is the major reason for enhanced durability. Here, in this paper, steam treatment was combined either with alkaline or with SO 2 to study. The solids obtained after steam treatments along with a control sample were dried and each was compacted into pellets. The pellets were then tested for durability. Steam treatment alone dominated improvements in durability. The pellet durability increased with the amount of xylose, but xylosemore » performed better in the pellet from raw poplar than did in the pellet from treated poplar. Water-soluble components contributed a maximum 4% of the durability of poplar pellets. The addition of lignin and sugars to substrates after steam treatment did not improve durability significantly. The surface modification that took place as a result of size reduction during steam treatment was the major reason, contributing about 50% of the durability of the pellet from steam-treated poplar. The acidity of steam treatment slightly affected the relative contributions of these structure changes on the durability. Lastly, the new knowledge helps tailor the chemical and/or mechanical pretreatment involved in pelleting biomass to durable pellets.« less

Self-repairing composites for airplane components

NASA Astrophysics Data System (ADS)

Dry, Carolyn

2008-03-01

Durability and damage tolerance criteria drives the design of most composite structures. Those criteria could be altered by developing structure that repairs itself from impact damage. This is a technology for increasing damage tolerance for impact damage. Repaired damage would enable continued function and prevent further degradation to catastrophic failure in the case of an aircraft application. Further, repaired damage would enable applications to be utilized without reduction in performance due to impacts. Self repairing structures are designed to incorporate hollow fibers, which will release a repairing agent when the structure is impacted, so that the repairing agent will fill delaminations, voids and cracks in les than one minute, thus healing matrix voids. The intent is to modify the durability and damage tolerance criteria by incorporation of self-healing technologies to reduce overall weight: The structure will actually remain lighter than current conventional design procedures allow. Research objective(s) were: Prove that damage can be repaired to within 80-90% of original flexural strength in less than one minute, in laminates that are processed at 300-350F typical for aircraft composites. These were successfully met. The main focus was on testing of elements in compression after impact and a larger component in shear at Natural Process Design, Inc. Based on these results the advantages purposes are assessed. The results show potential; with self repairing composites, compressive strength is maintained sufficiently so that less material can be used as per durability and damage tolerance, yielding a lighter structure.

Textile for heart valve prostheses: fabric long-term durability testing.

PubMed

Heim, Frederic; Durand, Bernard; Chakfe, Nabil

2010-01-01

The rapid developments and success in percutaneous vascular surgery over the last two decades with the now common stent grafts implantation, make the noninvasive surgery technique today attractive even for heart valve replacement. Less traumatic for the patient and also less time consuming, percutaneous heart valve replacement is however at its beginning and restricted to end of life patients. The noninvasive procedure expects from the heart valve prosthesis material to be resistant and adapted to folding requirements of the implantation process (catheter). Polyester fabric could be a suited material for heart valve implanted percutaneously. Highly flexible and resistant, polyester fabric proved to be well adapted to the dynamic behavior of a valve and polyester (Dacron) is also widely used for vascular grafts implantation and shows good biocompatibility and durability. However, today there's no data available on long-term durability of fabric used as heart valve material. The purpose of this work is to study the long term behavior of a microdenier polyester fabric construction under combined in vitro flexure and tension fatigue stress. In the novel in vitro testing technique presented, a fabric specimen was subjected to combined flexural and tensile fatigue generated by fluid flow under physiological pressure conditions. The results obtained show how flexural properties change with fatigue time, which reflects directly on the suitability of a fabric in such devices. It was also observed that these fabric structural changes directly influence the in vitro behavior of the textile heart valve prosthesis. (c) 2009 Wiley Periodicals, Inc.

Cumulative effect of transition metals on nitrogen and fluorine co-doped graphite nanofibers: an efficient and highly durable non-precious metal catalyst for the oxygen reduction reaction.

PubMed

Peera, S Gouse; Arunchander, A; Sahu, A K

2016-08-14

Nitrogen and fluorine co-doped graphite nanofibers (N/F-GNF) and their cumulative effect with Fe and Co have been developed as an alternative non-precious metal catalyst for efficient oxygen reduction reaction (ORR) in acidic media. The synergistic effect between the doped hetero atoms and the co-ordinated Fe and Co towards ORR activity and durability of the catalyst is deeply investigated. A high ORR onset potential comparable with commercial Pt/C catalyst is observed with the Fe-Co/NF-GNF catalyst, which indicates that this catalyst is a potential alternative to Pt/C. A fivefold increase in mass activity is achieved by the Fe-Co/NF-GNF catalyst compared to the simple N/F-GNF catalyst, which endorses the significant role of transition metal atoms in enhancing ORR activity. The advanced Fe-Co/NF-GNF catalyst also exhibits complete tolerance to CH3OH and CO. The Fe-Co/NF-GNF catalyst also exhibits excellent durability towards the ORR with only a 10 mV negative shift in its half wave potential after a 10 000 repeated potential cycling test, whereas in the case of a commercial Pt/C catalyst there was an ∼110 mV negative shift under similar environmental conditions. More stringent corrosive test cycles were also performed by maintaining the cell as high as 1.4 V with a later decrease to 0.6 V vs. RHE for 300 cycles, which showed the excellent durability of the Fe-Co/NF-GNF catalyst in comparison with the Pt/C catalyst. XPS analysis of the Fe-Co/NF-GNF catalyst presents the ORR active chemical states of N (pyridinic-N and graphitic-N) and F (semi-ionic-F) and the co-ordinated sites of Fe and Co species with the dopants. The excellent performance and durability of the Fe-Co/NF-GNF catalyst is due to the synergistic effect between the hetero atoms dopants (N and F) and strong co-ordinating bonds of M-N-C, which protect the graphene layers around the metallic species and greatly mitigates the leaching of Co and Fe during the long term cycling test. The high activity and long term durability of the Fe-Co/NF-GNF catalyst make it a promising ORR electrocatalyst for the fuel cell cathode reaction.

Five-level sub-axial cervical vertebrectomy and reconstruction: technical report.

PubMed

Reig, Adam; Parker, Scott L; McGirt, Matthew J

2014-05-01

Regardless of the etiology, severe cervical deformities can be extremely debilitating and are a challenge to correct. Often a multi-modality team approach is required to safely and effectively reduce the deformity, provide adequate decompression, and ensure solid fixation and fusion. In cases of iatrogenic cervical deformity necessitating five-level corpectomy and fixation, the feasibility, safety, and durability of this procedure remains unknown. We describe a patient who presented with debilitating pain and inability to eat due to an iatrogenic chin-on-chest cervical kyphotic deformity. The patient underwent a back-front-back staged procedure requiring five-level cervical vertebrectomy, C3-T1 anterior fixation, and occipital to T5 posterior fusion, resulting in successful reduction of cervical kyphosis from 75 to 0 degrees. At 6 months post-operatively, the patient demonstrated marked improvement in neurologic function and reported substantial improvements in neck pain-specific disability (NDI) and quality of life (SF-12 and EQ-5D). The feasibility and safety of five-level vertebrectomy and reconstruction for chin-on-chest deformity remains poorly described. The current case suggests that thoughtful planning that involves maximizing the patient's health status, judicious use of traction under direct neurological examination, staged circumferential release, and design of a construct that provides anterior and posterior column support with several points of fixation beyond the axis of rotation will attenuate the risk of peri-operative morbidity and potentiate the durability of deformity correction.

Advanced Turbine Technology Applications Project (ATTAP)

NASA Technical Reports Server (NTRS)

1990-01-01

Advanced Turbine Technology Application Project (ATTAP) activities during the past year were highlighted by test-bed engine design and development activities; ceramic component design; materials and component characterization; ceramic component process development and fabrication; component rig testing; and test-bed engine fabrication and testing. Although substantial technical challenges remain, all areas exhibited progress. Test-bed engine design and development activity included engine mechanical design, power turbine flow-path design and mechanical layout, and engine system integration aimed at upgrading the AGT-5 from a 1038 C metal engine to a durable 1371 C structural ceramic component test-bed engine. ATTAP-defined ceramic and associated ceramic/metal component design activities include: the ceramic combustor body, the ceramic gasifier turbine static structure, the ceramic gasifier turbine rotor, the ceramic/metal power turbine static structure, and the ceramic power turbine rotors. The materials and component characterization efforts included the testing and evaluation of several candidate ceramic materials and components being developed for use in the ATTAP. Ceramic component process development and fabrication activities are being conducted for the gasifier turbine rotor, gasifier turbine vanes, gasifier turbine scroll, extruded regenerator disks, and thermal insulation. Component rig testing activities include the development of the necessary test procedures and conduction of rig testing of the ceramic components and assemblies. Four-hundred hours of hot gasifier rig test time were accumulated with turbine inlet temperatures exceeding 1204 C at 100 percent design gasifier speed. A total of 348.6 test hours were achieved on a single ceramic rotor without failure and a second ceramic rotor was retired in engine-ready condition at 364.9 test hours. Test-bed engine fabrication, testing, and development supported improvements in ceramic component technology that will permit the achievement of program performance and durability goals. The designated durability engine accumulated 359.3 hour of test time, 226.9 of which were on the General Motors gas turbine durability schedule.

Technical - Economic Research for Passive Buildings

NASA Astrophysics Data System (ADS)

Miniotaite, Ruta

2017-10-01

A newly constructed passive house must save 80 % of heat resources; otherwise it is not a passive house. The heating energy demand of a passive building is less than 15 kWh/m2 per year. However, a passive house is something more than just an energy-saving house. This concept involves sustainable, high-quality, valuable, healthy and durable construction. Features of a passive house: high insulation of envelope components, high-quality windows, good tightness of the building, regenerative ventilation system and elimination of thermal bridges. The Energy Performance of Buildings Directive (EPBD) 61 requires all new public buildings to become near-zero energy buildings by 2019 and will be extended to all new buildings by 2021. This concept involves sustainable, high-quality, valuable, healthy and durable construction. Foundation, walls and roofs are the most essential elements of a house. The type of foundation for a private house is selected considering many factors. The article examines technological and structural solutions for passive buildings foundation, walls and roofs. The technical-economic comparison of the main structures of a passive house revealed that it is cheaper to install an adequately designed concrete slab foundation than to build strip or pile foundation and the floor separately. Timber stud walls are the cheapest wall option for a passive house and 45-51% cheaper compared to other options. The comparison of roofs and ceilings showed that insulation of the ceiling is 25% more efficient than insulation of the roof. The comparison of the main envelope elements efficiency by multiple-criteria evaluation methods showed that it is economically feasible to install concrete slab on ground foundation, stud walls with sheet cladding and a pitched roof with insulated ceiling.

Miniature ball-tip optical fibers for use in thulium fiber laser ablation of kidney stones

NASA Astrophysics Data System (ADS)

Wilson, Christopher R.; Hardy, Luke A.; Kennedy, Joshua D.; Irby, Pierce B.; Fried, Nathaniel M.

2016-01-01

Optical fibers, consisting of 240-μm-core trunk fibers with rounded, 450-μm-diameter ball tips, are currently used during Holmium:YAG laser lithotripsy to reduce mechanical damage to the inner lining of the ureteroscope working channel during fiber insertion and prolong ureteroscope lifetime. Similarly, this study tests a smaller, 100-μm-core fiber with 300-μm-diameter ball tip during thulium fiber laser (TFL) lithotripsy. TFL was operated at a wavelength of 1908 nm, with 35-mJ pulse energy, 500-μs pulse duration, and 300-Hz pulse rate. Calcium oxalate/phosphate stone samples were weighed, laser procedure times were measured, and ablation rates were calculated for ball tip fibers, with comparison to bare tip fibers. Photographs of ball tips were taken before and after each procedure to track ball tip degradation and determine number of procedures completed before need for replacement. A high speed camera also recorded the cavitation bubble dynamics during TFL lithotripsy. Additionally, saline irrigation rates and ureteroscope deflection were measured with and without the presence of TFL fiber. There was no statistical difference (P>0.05) between stone ablation rates for single-use ball tip fiber (1.3±0.4 mg/s) (n=10), multiple-use ball tip fiber (1.3±0.5 mg/s) (n=44), and conventional single-use bare tip fibers (1.3±0.2 mg/s) (n=10). Ball tip durability varied widely, but fibers averaged greater than four stone procedures before failure, defined by rapid decline in stone ablation rates. Mechanical damage at the front surface of the ball tip was the limiting factor in fiber lifetime. The small fiber diameter did not significantly impact ureteroscope deflection or saline flow rates. The miniature ball tip fiber may provide a cost-effective design for safe fiber insertion through the ureteroscope working channel and into the ureter without risk of instrument damage or tissue perforation, and without compromising stone ablation efficiency during TFL lithotripsy.

Effects of Compression, Staging, and Braid Angle on Braided Rope Seal Performance

NASA Technical Reports Server (NTRS)

Steinetz, Bruce M.; Dunlap, Patrick H.; Adams, Michael L.

2006-01-01

This viewgraph presentation describes the effects of compression, staging and braid angle on braided rope seals. The contents include: 1) Test Fixture Schematics; 2) Comparison of Hybrid Seal Braid Architecture; 3) Residual Interference After Compression Cycling; 4) Effect of Compression, Braid, and Staging on Seal Flow; 5) Effect of Staging on Seal Pressure Drop; 6) Three Stag Seal Durability; 7) P&W Turbine Vane Seal Requirements; and 8) Next Generation Fighter F-22 P&W F119 Engines.

Design criteria for maglev structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sandberg, H.R.; Williams, J.R.

1997-05-01

Maglev systems represent an entirely new concept in transportation. They will not operate on nor share the right-of-way with any other system. It is important, therefore, that the guideways be designed and constructed so as to be economical, constructable, durable, adaptable, reliable, and readily maintained. Comparisons should be made with the current transportation systems, especially highways and railroads. Since most of the guideway will be elevated, the comparison should be with the bridges. The object of the comparisons should be to avoid the shortcomings of the other systems while building on their strengths. This paper develops in some detail designmore » and construction criteria that will ensure a good, long-lived performance of the maglev guideway. The importance of beauty should have a low priority in comparison to the other design criteria. Clean, simple details meeting other criteria will ensure an acceptable appearance. These criteria were used in evaluating the four maglev concepts developed for the National Maglev Initiative.« less

Aggregate Freezing-Thawing Performance Using the Iowa Pore Index : final report.

DOT National Transportation Integrated Search

2016-10-01

In cold climates, the use of non-durable aggregate leads to premature pavement deterioration due to damage caused by freezing-thawing cycles. Differentiating durable and non-durable aggregates is a crucial yet challenging task. The frost durability o...

State-of-the-Art Report About Durability of Post-Tensioned Bridge Substructures

DOT National Transportation Integrated Search

1999-10-01

Durability design requires an understanding of the factors influencing durability and the measures necessary to improve durability of concrete structures. The objectives of this report are to: 1. Survey the condition of bridge substructures in Texas;...

Sensitivity study on durability variables of marine concrete structures

NASA Astrophysics Data System (ADS)

Zhou, Xin'gang; Li, Kefei

2013-06-01

In order to study the influence of parameters on durability of marine concrete structures, the parameter's sensitivity analysis was studied in this paper. With the Fick's 2nd law of diffusion and the deterministic sensitivity analysis method (DSA), the sensitivity factors of apparent surface chloride content, apparent chloride diffusion coefficient and its time dependent attenuation factor were analyzed. The results of the analysis show that the impact of design variables on concrete durability was different. The values of sensitivity factor of chloride diffusion coefficient and its time dependent attenuation factor were higher than others. Relative less error in chloride diffusion coefficient and its time dependent attenuation coefficient induces a bigger error in concrete durability design and life prediction. According to probability sensitivity analysis (PSA), the influence of mean value and variance of concrete durability design variables on the durability failure probability was studied. The results of the study provide quantitative measures of the importance of concrete durability design and life prediction variables. It was concluded that the chloride diffusion coefficient and its time dependent attenuation factor have more influence on the reliability of marine concrete structural durability. In durability design and life prediction of marine concrete structures, it was very important to reduce the measure and statistic error of durability design variables.

Characterization and Leaching Tests of the Fluidized Bed Steam Reforming (FBSR) Waste Form for LAW Immobilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neeway, James J.; Qafoku, Nikolla; Brown, Christopher F.

2013-10-01

Several supplemental technologies for treating and immobilizing Hanford low activity waste (LAW) have been evaluated. One such immobilization technology is the Fluidized Bed Steam Reforming (FBSR) granular product. The FBSR granular product is composed of insoluble sodium aluminosilicate (NAS) feldspathoid minerals. Production of the FBSR mineral product has been demonstrated both at the industrial and laboratory scale. Pacific Northwest National Laboratory (PNNL) was involved in an extensive characterization campaign. This goal of this campaign was study the durability of the FBSR mineral product and the mineral product encapsulated in a monolith to meet compressive strength requirements. This paper gives anmore » overview of results obtained using the ASTM C 1285 Product Consistency Test (PCT), the EPA Test Method 1311 Toxicity Characteristic Leaching Procedure (TCLP), and the ASTMC 1662 Single-Pass Flow-Through (SPFT) test. Along with these durability tests an overview of the characteristics of the waste form has been collected using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), microwave digestions for chemical composition, and surface area from Brunauer, Emmett, and Teller (BET) theory.« less

Characterization and Leaching Tests of the Fluidized Bed Steam Reforming (FBSR) Waste Form for LAW Immobilization - 13400

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neeway, James J.; Qafoku, Nikolla P.; Peterson, Reid A.

2013-07-01

Several supplemental technologies for treating and immobilizing Hanford low activity waste (LAW) have been evaluated. One such immobilization technology is the Fluidized Bed Steam Reforming (FBSR) granular product. The FBSR granular product is composed of insoluble sodium aluminosilicate (NAS) feldspathoid minerals. Production of the FBSR mineral product has been demonstrated both at the industrial and laboratory scale. Pacific Northwest National Laboratory (PNNL) was involved in an extensive characterization campaign. The goal of this campaign was to study the durability of the FBSR mineral product and the encapsulated FBSR product in a geo-polymer monolith. This paper gives an overview of resultsmore » obtained using the ASTM C 1285 Product Consistency Test (PCT), the EPA Test Method 1311 Toxicity Characteristic Leaching Procedure (TCLP), and the ASTMC 1662 Single-Pass Flow-Through (SPFT) test. Along with these durability tests an overview of the characteristics of the waste form has been collected using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), microwave digestions for chemical composition, and surface area from Brunauer, Emmett, and Teller (BET) theory. (authors)« less

Comparison of shrinkage related properties of various patch repair materials

NASA Astrophysics Data System (ADS)

Kristiawan, S. A.; Fitrianto, R. S.

2017-02-01

A patch repair material has been developed in the form of unsaturated polyester resin (UPR)-mortar. The performance and durability of this material are governed by its compatibility with the concrete being repaired. One of the compatibility issue that should be tackled is the dimensional compatibility as a result of differential shrinkage between the repair material and the concrete substrate. This research aims to evaluate such shrinkage related properties of UPR-mortar and to compare with those of other patch repair materials. The investigation includes the following aspects: free shrinkage, resistance to delamination and cracking. The results indicate that UPR-mortar poses a lower free shrinkage, lower risk of both delamination and cracking tendency in comparison to other repair materials.

Alternatives to SiOx for protective scan mirror coatings in remote sensing instruments

NASA Astrophysics Data System (ADS)

MacDonald, Michael E.

1999-09-01

Mirrors in remote sensing instruments require durable dielectric coatings, both to prevent oxidation of the reflective surface and to protect it during cleaning. IR absorption bands within widely-used SiOx coatings produce scene radiance and instrument background variations as a function of scan mirror angle which motivate the search for possible substitute materials. In this work several candidate coatings are evaluated including CeF3, HfO2, MgF2 SrF2, and Y2O3. This evaluation consists of reflectance, adhesion, and durability measurements of mirrors with an aluminum reflective surface over-coated with these materials. S-polarized and P- polarized reflectance measurements are presented between 2 and 20 micrometers for incidence angles between 40 and 50 degrees. This angular range is sufficient to scan the earth disk from geostationary orbit. Additional measurements at 45 degrees incidence are presented between 2 and 55 micrometers , covering the IR wavelength range of interest for earth radiation budget sensors. Comparisons are drawn with measurements of scan- mirror witness samples from the imaging and sounding instruments used in the Geostationary Operational Environmental Satellite (GOES). These witness samples exhibit reflectance variations arising from IR absorption bands in the SiOx protective coatings used in these mirrors. The spectral characteristics of several of the alternate materials are found to be quite attractive, however durable coatings of some of these materials require elevated deposition temperature which are incompatible with the nickel-coated beryllium scan mirror substrate construction used in GOES. This work present the achievable reflectance and durability of these alternate dielectric protective coatings at the deposition temperature constraints imposed by the scan mirror substrate. The prospects for substituting one of these coatings for SiOx are evaluated, and contrasted with the capability of radiometric calibration techniques to deal with the reflectance variations produced by SiOx coatings.

Design features to enhance external hip protector adherence in the nursing home setting.

PubMed

Honkanen, Lisa A; Dehner, Melissa L; Lachs, Mark S

2006-11-01

To determine the preferences for external hip protector (EHP) design features of both certified nursing assistants (CNAs) and nursing home laundry personnel, and to test the durability of favored model features. Cross-sectional descriptive study of CNAs' and laundry personnels' preferences and a prospective experimental study of EHP fastener durability under institutional laundry conditions. Three urban nursing homes and a hospital-based laundry service. Twenty-seven CNAs, 4 laundry service supervisors. Five focus groups with CNAs and a survey of laundry supervisors were conducted to elicit preferences of EHP design features with an emphasis on convenience and durability. A laundry test of 20 EHPs was conducted to compare these design features. There was wide agreement among CNAs and laundry personnel that EHPs with soft pads in garments of light neutral colors, and cotton-blend fabrics were most preferred. CNAs preferred sewn-in pads to removeable ones, but laundry personnel had no consensus on this issue. For dependent residents, wraparound (front opening) garments using Velcro were preferred by CNAs, whereas laundry supervisors preferred snap closures. When EHP underwent repeated washing in the laundry test, Velcro and snaps were functionally comparable at 52 cycles. Garments constructed of heavyweight cotton blends, polyester, or cotton with spandex maintained elasticity at 52 weeks, whereas the lightweight cotton blend stretched significantly. Based on CNAs' preferences, laundry personnels' input, and a laundry test, EHP design features that could enhance both caregiver efficiency and resident comfort include soft pads sewn into a light-colored (but non-white) heavier weight cotton-blend garment, with the availability of both a pull-up style and a wraparound style using Velcro fasteners. Snaps did not demonstrate superior durability in the laundry test, but further comparison with Velcro under clinical conditions is indicated. Education and inclusion of CNAs in EHP decision making are important ways to improve EHP adherence.

A high temperature fatigue life prediction computer code based on the total strain version of StrainRange Partitioning (SRP)

NASA Technical Reports Server (NTRS)

Mcgaw, Michael A.; Saltsman, James F.

1993-01-01

A recently developed high-temperature fatigue life prediction computer code is presented and an example of its usage given. The code discussed is based on the Total Strain version of Strainrange Partitioning (TS-SRP). Included in this code are procedures for characterizing the creep-fatigue durability behavior of an alloy according to TS-SRP guidelines and predicting cyclic life for complex cycle types for both isothermal and thermomechanical conditions. A reasonably extensive materials properties database is included with the code.

Repair, Evaluation, Maintenance, and Rehabilitation Research Program. State-of-the-Art Procedures for Sealing Coastal Structures with Grouts and Concretes

DTIC Science & Technology

1989-04-01

the shape it had as it was ex- truded from the grout tube . Figure 3 shows the type of voids in which the ma- terial is expected to form a barrier...has promising characteristics for coastal engi- neering applications. Microfine Cement, a company which markets ultrafine ce- ment, claims the product...can penetrate fine sand, and is strong and durable with a 4- to 5-hr set time. Fifty percent of Microfine Cement’s particles are less than 4 microns

X-ray Computed Tomography Assessment of Air Void Distribution in Concrete

NASA Astrophysics Data System (ADS)

Lu, Haizhu

Air void size and spatial distribution have long been regarded as critical parameters in the frost resistance of concrete. In cement-based materials, entrained air void systems play an important role in performance as related to durability, permeability, and heat transfer. Many efforts have been made to measure air void parameters in a more efficient and reliable manner in the past several decades. Standardized measurement techniques based on optical microscopy and stereology on flat cut and polished surfaces are widely used in research as well as in quality assurance and quality control applications. Other more automated methods using image processing have also been utilized, but still starting from flat cut and polished surfaces. The emergence of X-ray computed tomography (CT) techniques provides the capability of capturing the inner microstructure of materials at the micrometer and nanometer scale. X-ray CT's less demanding sample preparation and capability to measure 3D distributions of air voids directly provide ample prospects for its wider use in air void characterization in cement-based materials. However, due to the huge number of air voids that can exist within a limited volume, errors can easily arise in the absence of a formalized data processing procedure. In this study, air void parameters in selected types of cement-based materials (lightweight concrete, structural concrete elements, pavements, and laboratory mortars) have been measured using micro X-ray CT. The focus of this study is to propose a unified procedure for processing the data and to provide solutions to deal with common problems that arise when measuring air void parameters: primarily the reliable segmentation of objects of interest, uncertainty estimation of measured parameters, and the comparison of competing segmentation parameters.

40 CFR 86.094-26 - Mileage and service accumulation; emission requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-duty vehicles. It prescribes mileage and service accumulation requirements for durability data vehicles... Durability Program of § 86.094-13(d), and for emission data vehicles regardless of the durability program employed. Service accumulation requirements for durability data vehicles run under the Alternative Service...

76 FR 43808 - Designation of Biobased Items for Federal Procurement

Federal Register 2010, 2011, 2012, 2013, 2014

2011-07-22

... thermal shipping containers, including durable and non-durable thermal shipping containers as... able to utilize this Web site as one tool to determine the availability of qualifying biobased products... containers and the subcategories are (1) durable thermal shipping containers, and (2) non-durable thermal...

31 CFR 240.17 - Powers of attorney.

Code of Federal Regulations, 2013 CFR

2013-07-01

... following a determination that the named payee is incompetent. (e) Springing durable special powers of attorney. A springing durable special power of attorney is similar to a durable power of attorney except... special power of attorney, a springing durable special power of attorney is created by the principal's use...

31 CFR 240.17 - Powers of attorney.

Code of Federal Regulations, 2011 CFR

2011-07-01

... following a determination that the named payee is incompetent. (e) Springing durable special powers of attorney. A springing durable special power of attorney is similar to a durable power of attorney except... special power of attorney, a springing durable special power of attorney is created by the principal's use...

What Bariatric Surgery Can Teach Us About Endoluminal Treatment of Obesity and Metabolic Disorders.

PubMed

Kaplan, Lee M

2017-04-01

Bariatric surgical procedures, including gastric bypass, vertical sleeve gastrectomy, and biliopancreatic diversion, are the most effective and durable treatments for obesity. In addition, These operations induce metabolic changes that provide weight-independent improvement in type 2 diabetes, fatty liver disease and other metabolic disorders. Initially thought to work by mechanical restriction of food intake or malabsorption of ingested nutrients, these procedures are now known to work through complex changes in neuroendocrine and immune signals emanating from the gut, including peptide hormones, bile acids, vagal nerve activity, and metabolites generated by the gut microbiota, all collaborating to reregulate appetite, food preference, and energy expenditure. Development of less invasive means of achieving these benefits would allow much greater dissemination of effective, gastrointestinal (GI)-targeted therapies for obesity and metabolic disorders. To reproduce the benefits of bariatric surgery, however, these endoscopic procedures and devices will need to mimic the physiological rather than the mechanical effects of these operations. Copyright © 2017 Elsevier Inc. All rights reserved.

Aortic valve surgery of the 21st century: sutureless AVR versus TAVI.

PubMed

Costache, Victor S; Moldovan, Horatiu; Arsenescu, Catalina; Costache, Andreea

2018-04-01

Surgical aortic valve replacement (sAVR) has been a safe, effective and time-proven technique and is still the standard of care all over the world for aortic valve treatment. The vast majority of centers perform this procedure by doing a median sternotomy with several disadvantages. While many others specialties went minimally invasive decades ago, in cardiovascular field transcatheter valve implantation was the first minimally invasive valvular procedure that gained rapid worldwide acceptance. Transcatheter valve replacement (TAVR) is now marketed as a procedure that should be performed under local anesthesia, by an interventional cardiologist via trans femoral route with no other healthcare professional invited to the patient selection or case planning. An increasing number of surgeons are promoting minimally invasive aortic valve replacement, which is gaining grounds, especially with the help of the new sutureless valve technology. With these two new technologies emerging, legitimate questions arise and need to be answered - which has the longest durability, lower complication rate and lower overall mortality.

Attachment techniques for high temperature strain

NASA Astrophysics Data System (ADS)

Wnuk, Steve P., Jr.

1993-01-01

Attachment methods for making resistive strain measurements to 2500 F were studied. A survey of available strain gages and attachment techniques was made, and the results are compiled for metal and carbon composite test materials. A theoretical analysis of strain transfer into a bonded strain gage was made, and the important physical parameters of the strain transfer medium, the ceramic matrix, were identified. A pull tester to measure pull-out tests on commonly used strain gage cements indicated that all cements tested displayed adequate strength for good strain transfer. Rokide flame sprayed coatings produced significantly stronger bonds than ceramic cements. An in-depth study of the flame spray process produced simplified installation procedures which also resulted in greater reliability and durability. Application procedures incorporating improvements made during this program are appended to the report. Strain gages installed on carbon composites, Rene' 41, 316 stainless steel, and TZM using attachment techniques developed during this program were successfully tested to 2500 F. Photographs of installation techniques, test procedures, and graphs of the test data are included in this report.

Multi-factor Effects on the Durability of Recycle Aggregate Concrete

NASA Astrophysics Data System (ADS)

Ma, Huan; Cui, Yu-Li; Zhu, Wen-Yu; Xie, Xian-Jie

2016-05-01

Recycled Aggregate Concrete (RAC) was prepared with different recycled aggregate replacement ratio, 0, 30%, 70% and 100% respectively. The performances of RAC were examined by the freeze-thaw cycle, carbonization and sulfate attack to assess the durability. Results show that test sequence has different effects on the durability of RAC; the durability is poorer when carbonation experiment was carried out firstly, and then other experiment was carried out again; the durability is better when recycled aggregate replacement ratio is 70%.

Durable Airtightness in Single-Family Dwellings - Field Measurementsand Analysis

DOE PAGES

Chan, Wanyu R.; Walker, Iain S.; Sherman, Max H.

2015-06-01

Here, durability of the building envelope is important to new homes that are increasingly built with improved levels of airtightness. It is also important to weatherized homes such that energy savings from retrofit measures, such as air sealing, are persistent. This paper presents a comparison of air leakage measurements collected in November 2013 through March 2014, with two sets of prior data collected between 2001-2003 from 17 new homes located near Atlanta, GA, and 17 homes near Boise, ID that were weatherized in 2007- 2008. The purpose of the comparison is to determine if there are changes to the airtightnessmore » of building envelopes over time. The air leakage increased in all but one of the new homes, with a mean increase of about 25%. The weatherized homes also showed an increase in the mean air leakage (12%). A regression analysis was performed to describe the relationship between prior and current measurements in terms of normalized leakage (NL). The best estimate of the ageing factor predicts a 15% increase in NL over ten years. Further analysis using ResDB data (LBNL’s Residential Diagnostic Database) showed the expected changes in air leakage if ageing were modelled. These results imply the need to examine the causes of increased leakage and methods to avoid them. This increase in leakage with time should be accounted for in long-term population-wide energy savings estimates, such as those used in ratings or energy savings programs.« less

42 CFR 414.229 - Other durable medical equipment-capped rental items.

Code of Federal Regulations, 2011 CFR

2011-10-01

... AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM PAYMENT FOR PART B MEDICAL AND OTHER HEALTH SERVICES Payment for Durable Medical Equipment and Prosthetic and Orthotic Devices § 414.229 Other durable medical... 42 Public Health 3 2011-10-01 2011-10-01 false Other durable medical equipment-capped rental items...

42 CFR 414.229 - Other durable medical equipment-capped rental items.

Code of Federal Regulations, 2010 CFR

2010-10-01

... AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM PAYMENT FOR PART B MEDICAL AND OTHER HEALTH SERVICES Payment for Durable Medical Equipment and Prosthetic and Orthotic Devices § 414.229 Other durable medical... 42 Public Health 3 2010-10-01 2010-10-01 false Other durable medical equipment-capped rental items...

30 CFR 817.73 - Disposal of excess spoil: Durable rock fills.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Disposal of excess spoil: Durable rock fills...-UNDERGROUND MINING ACTIVITIES § 817.73 Disposal of excess spoil: Durable rock fills. The regulatory authority may approve the alternative method of disposal of excess durable rock spoil by gravity placement in...

30 CFR 816.73 - Disposal of excess spoil: Durable rock fills.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Disposal of excess spoil: Durable rock fills...-SURFACE MINING ACTIVITIES § 816.73 Disposal of excess spoil: Durable rock fills. The regulatory authority may approve the alternative method of disposal of excess durable rock spoil by gravity placement in...

30 CFR 817.73 - Disposal of excess spoil: Durable rock fills.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Disposal of excess spoil: Durable rock fills...-UNDERGROUND MINING ACTIVITIES § 817.73 Disposal of excess spoil: Durable rock fills. The regulatory authority may approve the alternative method of disposal of excess durable rock spoil by gravity placement in...

30 CFR 817.73 - Disposal of excess spoil: Durable rock fills.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Disposal of excess spoil: Durable rock fills...-UNDERGROUND MINING ACTIVITIES § 817.73 Disposal of excess spoil: Durable rock fills. The regulatory authority may approve the alternative method of disposal of excess durable rock spoil by gravity placement in...

30 CFR 817.73 - Disposal of excess spoil: Durable rock fills.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Disposal of excess spoil: Durable rock fills...-UNDERGROUND MINING ACTIVITIES § 817.73 Disposal of excess spoil: Durable rock fills. The regulatory authority may approve the alternative method of disposal of excess durable rock spoil by gravity placement in...

30 CFR 817.73 - Disposal of excess spoil: Durable rock fills.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Disposal of excess spoil: Durable rock fills...-UNDERGROUND MINING ACTIVITIES § 817.73 Disposal of excess spoil: Durable rock fills. The regulatory authority may approve the alternative method of disposal of excess durable rock spoil by gravity placement in...

30 CFR 816.73 - Disposal of excess spoil: Durable rock fills.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 3 2012-07-01 2012-07-01 false Disposal of excess spoil: Durable rock fills...-SURFACE MINING ACTIVITIES § 816.73 Disposal of excess spoil: Durable rock fills. The regulatory authority may approve the alternative method of disposal of excess durable rock spoil by gravity placement in...

30 CFR 816.73 - Disposal of excess spoil: Durable rock fills.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 3 2014-07-01 2014-07-01 false Disposal of excess spoil: Durable rock fills...-SURFACE MINING ACTIVITIES § 816.73 Disposal of excess spoil: Durable rock fills. The regulatory authority may approve the alternative method of disposal of excess durable rock spoil by gravity placement in...

30 CFR 816.73 - Disposal of excess spoil: Durable rock fills.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 3 2011-07-01 2011-07-01 false Disposal of excess spoil: Durable rock fills...-SURFACE MINING ACTIVITIES § 816.73 Disposal of excess spoil: Durable rock fills. The regulatory authority may approve the alternative method of disposal of excess durable rock spoil by gravity placement in...

30 CFR 816.73 - Disposal of excess spoil: Durable rock fills.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 3 2013-07-01 2013-07-01 false Disposal of excess spoil: Durable rock fills...-SURFACE MINING ACTIVITIES § 816.73 Disposal of excess spoil: Durable rock fills. The regulatory authority may approve the alternative method of disposal of excess durable rock spoil by gravity placement in...

Rationale of a novel study design for the BIOFLOW V study, a prospective, randomized multicenter study to assess the safety and efficacy of the Orsiro sirolimus-eluting coronary stent system using a Bayesian approach.

PubMed

Doros, Gheorghe; Massaro, Joseph M; Kandzari, David E; Waksman, Ron; Koolen, Jacques J; Cutlip, Donald E; Mauri, Laura

2017-11-01

Traditional study design submitted to the Food and Drug Administration to test newer drug-eluting stents (DES) for marketing approval is the prospective randomized controlled trial. However, several DES have extensive clinical data from trials conducted outside the United States that have led to utilization of a novel design using the Bayesian approach. This design was proposed for testing DES with bioresorbable polymer compared with DES most commonly in use today that use durable polymers for drug elution. This prospective, multicenter, randomized, controlled trial is designed to assess the safety and efficacy of the Orsiro bioresorbable polymer sirolimus-eluting stent (BP SES). Up to 1,334 subjects with up to 3 de novo or restenotic coronary artery lesions who qualify for percutaneous coronary intervention with stenting will be randomized 2:1 to the BP SES versus the Xience durable polymer everolimus-eluting stent (DP EES). Data from this trial will be combined with data from 2 similarly designed trials that also randomize subjects to BP SES and DP EES (BIOFLOW II, N=452 and BIOFLOW IV, N=579) by using a Bayesian approach. The primary end point is target lesion failure at 12 months post index procedure, defined as cardiac death, target vessel myocardial infarction, or clinically driven target lesion revascularization, and the primary analysis is a test of noninferiority of the BP SES versus DP EES on the primary end point according to a noninferiority delta of 3.85%. Secondary end points include stent thrombosis and the individual components of target lesion failure. Subjects will be followed for 5 years after randomization. The BIOFLOW V trial offers an opportunity to assess clinical outcomes in patients treated with coronary revascularization using the Orsiro BP SES relative to a commonly used DP EES. The use of a Bayesian analysis combines a large randomized cohort of patients 2 two smaller contributing randomized trials to augment the efficiency of the comparison. Copyright © 2017 Elsevier Inc. All rights reserved.

CESIUM REMOVAL FROM TANKS 241-AN-103 & 241-SX-105 & 241-AZ-101/102 COMPOSITE FOR TESTING IN BENCH SCALE STEAM REFORMER

DOE Office of Scientific and Technical Information (OSTI.GOV)

DUNCAN JB; HUBER HJ

2011-06-08

This report documents the preparation of three actual Hanford tank waste samples for shipment to the Savannah River National Laboratory (SRNL). Two of the samples were dissolved saltcakes from tank 241-AN-103 (hereafter AN-103) and tank 241-SX-105 (hereafter SX-105); one sample was a supernate composite from tanks 241-AZ-101 and 241-AZ-102 (hereafter AZ-101/102). The preparation of the samples was executed following the test plans LAB-PLAN-10-00006, Test Plan for the Preparation of Samples from Hanford Tanks 241-SX-105, 241-AN-103, 241-AN-107, and LAB-PLN-10-00014, Test Plan for the Preparation of a Composite Sample from Hanford Tanks 241-AZ-101 and 241-AZ-102 for Steam Reformer Testing at the Savannahmore » River National Laboratory. All procedural steps were recorded in laboratory notebook HNF-N-274 3. Sample breakdown diagrams for AN-103 and SX-105 are presented in Appendix A. The tank samples were prepared in support of a series of treatability studies of the Fluidized Bed Steam Reforming (FBSR) process using a Bench-Scale Reformer (BSR) at SRNL. Tests with simulants have shown that the FBSR mineralized waste form is comparable to low-activity waste glass with respect to environmental durability (WSRC-STI-2008-00268, Mineralization of Radioactive Wastes by Fluidized Bed Steam Reforming (FBSR): Comparisons to Vitreous Waste Forms and Pertinent Durability Testing). However, a rigorous assessment requires long-term performance data from FB SR product formed from actual Hanford tank waste. Washington River Protection Solutions, LLC (WRPS) has initiated a Waste Form Qualification Program (WP-S.2.1-20 1 0-00 1, Fluidized Bed Steam Reformer Low-level Waste Form Qualification) to gather the data required to demonstrate that an adequate FBSR mineralized waste form can be produced. The documentation of the selection process of the three tank samples has been separately reported in RPP-48824, 'Sample Selection Process for Bench-Scale Steam Reforming Treatability Studies Using Hanford Waste Samples.'« less

CESIUM REMOVAL FROM TANKS 241-AN-103 & 241-SX-105 & 241-AZ-101 & 241AZ-102 COMPOSITE FOR TESTING IN BENCH SCALE STEAM REFORMER

DOE Office of Scientific and Technical Information (OSTI.GOV)

DUNCAN JB; HUBER HJ

2011-04-21

This report documents the preparation of three actual Hanford tank waste samples for shipment to the Savannah River National Laboratory (SRNL). Two of the samples were dissolved saltcakes from tank 241-AN-103 (hereafter AN-103) and tank 241-SX-105 (hereafter SX-105); one sample was a supernate composite from tanks 241-AZ-101 and 241-AZ-102 (hereafter AZ-101/102). The preparation of the samples was executed following the test plans LAB-PLAN-10-00006, Test Plan for the Preparation of Samples from Hanford Tanks 241-SX-105, 241-AN-103, 241-AN-107, and LAB-PLN-l0-00014, Test Plan for the Preparation of a Composite Sample from Hanford Tanks 241-AZ-101 and 241-AZ-102 for Steam Reformer Testing at the Savannahmore » River National Laboratory. All procedural steps were recorded in laboratory notebook HNF-N-274 3. Sample breakdown diagrams for AN-103 and SX-105 are presented in Appendix A. The tank samples were prepared in support of a series of treatability studies of the Fluidized Bed Steam Reforming (FBSR) process using a Bench-Scale Reformer (BSR) at SRNL. Tests with simulants have shown that the FBSR mineralized waste form is comparable to low-activity waste glass with respect to environmental durability (WSRC-STI-2008-00268, Mineralization of Radioactive Wastes by Fluidized Bed Steam Reforming (FBSR): Comparisons to Vitreous Waste Forms and Pertinent Durability Testing). However, a rigorous assessment requires long-term performance data from FBSR product formed from actual Hanford tank waste. Washington River Protection Solutions, LLC (WRPS) has initiated a Waste Form Qualification Program (WP-5.2.1-2010-001, Fluidized Bed Steam Reformer Low-level Waste Form Qualification) to gather the data required to demonstrate that an adequate FBSR mineralized waste form can be produced. The documentation of the selection process of the three tank samples has been separately reported in RPP-48824, Sample Selection Process for Bench-Scale Steam Reforming Treatability Studies Using Hanford Waste Samples.« less

Highly Dispersed Alloy Catalyst for Durability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vivek S. Murthi; Izzo, Elise; Bi, Wu

2013-01-08

Achieving DOE's stated 5000-hr durability goal for light-duty vehicles by 2015 will require MEAs with characteristics that are beyond the current state of the art. Significant effort was placed on developing advanced durable cathode catalysts to arrive at the best possible electrode for high performance and durability, as well as developing manufacturing processes that yield significant cost benefit. Accordingly, the overall goal of this project was to develop and construct advanced MEAs that will improve performance and durability while reducing the cost of PEMFC stacks. The project, led by UTC Power, focused on developing new catalysts/supports and integrating them withmore » existing materials (membranes and gas diffusion layers (GDLs)) using state-of-the-art fabrication methods capable of meeting the durability requirements essential for automotive applications. Specifically, the project work aimed to lower platinum group metals (PGM) loading while increasing performance and durability. Appropriate catalysts and MEA configuration were down-selected that protects the membrane, and the layers were tailored to optimize the movements of reactants and product water through the cell to maximize performance while maintaining durability.« less

A comparison of the Monti and spiral Monti procedures: A long-term analysis.

PubMed

Whittam, B M; Szymanski, K M; Flack, C; Misseri, R; Kaefer, M; Rink, R C; Cain, M P

2015-06-01

The Monti ileovesicostomy provides an excellent substitution for an appendicovesicostomy when the appendix is unavailable or suitable for use. The spiral Monti is a useful modification to the traditional Monti as it allows creation of a longer channel when needed. In 2007, the short-term outcomes were reported; they compared traditional and spiral Monti in 188 patients with an average follow-up of 43 months. In the present population, a total of 25 subfasical revisions were performed in 21 patients: nine (8.3%) subfascial revisions in the traditional Monti (TM) patients and 12 (15.2%) subfascial revisions in the spiral Monti (SM) patients. The study found an increased risk of subfascial revisions of either TM or SM when the stoma was located at the umbilicus versus right lower quadrant (16.8% vs 6.3%, P < 0.05). On subgroup analysis, this increased subfascial revision rate appeared to be driven by SM channels to the umbilicus rather than other stomal locations, but this trend was not statistically significant. It was hypothesized that with longer follow-up, the spiral Monti would require more subfascial revisions due to progressive lengthening of the channel. A retrospective chart review was performed for all patients undergoing a traditional Monti (TM) or spiral Monti (SM) procedure at the present institution (1997-2013). Patient demographics, bowel segment used, stomal location, channel or stomal revisions, number of anesthetic endoscopic procedures performed, and indications for revision were reviewed. Kaplan-Meier analysis and Cox proportional hazards modeling was used for analysis. Of the 296 patients identified, 146 had Monti procedures and 150 had spiral Monti procedures (median follow-up 7.7 years). Median age at surgery was 10.6 years. Myelomeningocele was the most common underlying cause of neuropathic bladder, totaling 169 (57.1%) patients. Stomas were located at the umbilicus (106, 35.8%), right lower quadrant (183, 61.8%) and left lower quadrant (seven, 2.4%). Median follow-up for the entire cohort was 7.7 years (range: 1 month-15.7 years). Stomal stenosis rate was 7.4%, and 96.6% of the channels were continent. A total of 87 revisions were performed in 74 patients (25.0%). Of these, 55 were subfascial revisions in 49 patients (16.6%). The umbilical spiral Monti on univariate and multivariate analysis was found to be over twice as likely to undergo subfascial revision. The majority of patients with a Monti channel had durable results and did not require further channel surgery with long-term follow-up. Spiral Monti channels to the umbilicus were more than twice as likely to undergo subfascial revision compared to all other Monti channels. Overall, one in three umbilical SM channels required a subfascial revision at 10 years after the initial surgery, compared to one in six of all other Monti channels. The study was limited by being a retrospective, single-center series; however, it does represent the largest series of pure SM and TM patients. It focused only on surgical interventions, thus was likely to underestimate the overall risk of complications, as some complications were managed conservatively. As in all studies, some patients were lost to follow-up and inevitably some of these may have had complications. Correction for this was attempted through survival analysis. The present study reported durable and reliable long-term results with Monti and spiral Monti procedures based on a large patient cohort. Spiral Monti to the umbilicus was more than twice as likely to require a subfascial revision. Copyright © 2015 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

Inter-comparison of Computer Codes for TRISO-based Fuel Micro-Modeling and Performance Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brian Boer; Chang Keun Jo; Wen Wu

2010-10-01

The Next Generation Nuclear Plant (NGNP), the Deep Burn Pebble Bed Reactor (DB-PBR) and the Deep Burn Prismatic Block Reactor (DB-PMR) are all based on fuels that use TRISO particles as their fundamental constituent. The TRISO particle properties include very high durability in radiation environments, hence the designs reliance on the TRISO to form the principal barrier to radioactive materials release. This durability forms the basis for the selection of this fuel type for applications such as Deep Bun (DB), which require exposures up to four times those expected for light water reactors. It follows that the study and predictionmore » of the durability of TRISO particles must be carried as part of the safety and overall performance characterization of all the designs mentioned above. Such evaluations have been carried out independently by the performers of the DB project using independently developed codes. These codes, PASTA, PISA and COPA, incorporate models for stress analysis on the various layers of the TRISO particle (and of the intervening matrix material for some of them), model for fission products release and migration then accumulation within the SiC layer of the TRISO particle, just next to the layer, models for free oxygen and CO formation and migration to the same location, models for temperature field modeling within the various layers of the TRISO particle and models for the prediction of failure rates. All these models may be either internal to the code or external. This large number of models and the possibility of different constitutive data and model formulations and the possibility of a variety of solution techniques makes it highly unlikely that the model would give identical results in the modeling of identical situations. The purpose of this paper is to present the results of an inter-comparison between the codes and to identify areas of agreement and areas that need reconciliation. The inter-comparison has been carried out by the cooperating institutions using a set of pre-defined TRISO conditions (burnup levels, temperature or power levels, etc.) and the outcome will be tabulated in the full length paper. The areas of agreement will be pointed out and the areas that require further modeling or reconciliation will be shown. In general the agreement between the codes is good within less than one order of magnitude in the prediction of TRISO failure rates.« less

Impact of transoral incisionless fundoplication (TIF) on subjective and objective GERD indices: a systematic review of the published literature.

PubMed

Wendling, Mark R; Melvin, W Scott; Perry, Kyle A

2013-10-01

Gastroesophageal reflux disease (GERD) remains a significant problem for the medical community. Many endoluminal treatments for GERD have been developed with little success. Currently, transoral incisionless fundoplication (TIF) attempts to recreate a surgical fundoplication through placement of full-thickness polypropylene H-fasteners. This, the most recent procedure to gain FDA approval, has shown some promise in the early data. However, questions of its safety profile, efficacy, and durability remain. The Cochrane Library and MEDLINE through PubMed were searched to identify published studies reporting on subjective and objective GERD indices after TIF. The search was limited to human studies published in English from 2006 up to March 2012. Data collected included GERD-HRQL and RSI scores, PPI discontinuation and patient satisfaction rates, pH study metrics, complications, and treatment failures. Statistical analysis was performed with weighted t tests. Titles and abstracts of 214 papers were initially reviewed. Fifteen studies were found to be eligible, reporting on over 550 procedures. Both GERD-HRQL scores (21.9 vs. 5.9, p < 0.0001) and RSI scores (24.5 vs. 5.4, p ≤ 0.0001) were significantly reduced after TIF. Overall patient satisfaction was 72 %. The overall rate of PPI discontinuation was 67 % across all studies, with a mean follow-up of 8.3 months. pH metrics were not consistently normalized. The major complication rate was 3.2 % and the failure rate was 7.2 % across all studies. TIF appears to provide symptomatic relief with reasonable levels of patient satisfaction at short-term follow-up. A well-designed prospective clinical trial is needed to assess the effectiveness and durability of TIF as well as to identify the patient population that will benefit from this procedure.

A 5-year study of the transmalar subperiosteal midface lift with minimal skin and superficial musculoaponeurotic system dissection: a durable, natural-appearing lift with less surgery and recovery time.

PubMed

Finger, E R

2001-04-15

The transmalar subperiosteal midface lift is a simple, direct-approach procedure to be performed with a meloplasty. The entry into the midface is at the site of maximum suture tension, which allows for more elevation. The skin is elevated enough to expose the entry site, which is on the zygoma just cephalad to the origins of the zygomaticus muscles. Through a small hole at that site, a periosteal elevator is used for the midface dissection. This is a blind dissection, and the technique is described. The advantages of the technique are that there is (1) no lower-lid incision or risk of an ectropion, (2) a resultant tightening and elevation of the lower lid, (3) more elevation and durability because the zygomaticus muscle origins are elevated with the periosteum and are sutured to the very substantial deep temporal fascia, (4) a simple and fast procedure, and (5) no telltale sign of a face lift. Both the superficial musculoaponeurotic system (SMAS) and the skin are substantially elevated with the transmalar subperiosteal midface lift to the extent that they should be only minimally dissected. In the author's opinion, the extended dissection of the skin and/or the SMAS does not increase the amount of tissue lift and probably reduces it in most cases, considering that the goal is a natural look and not one that appears pulled or stretched. The skin is elevated only for exposure, and the SMAS is elevated only enough to create a preauricular SMAS-platysma flap to tighten the neck. With two fewer layers of dissection, there is significantly less postoperative swelling and recovery time. The article presents the technique, the results on 272 patients over a period of 5 years, and a discussion. No patients described have had secondary procedures such as lasers, so the transmalar subperiosteal midface lift can be evaluated on its own merit.

[Endo-exo prostheses : Osseointegrated percutaneously channeled implants for rehabilitation after limb amputation].

PubMed

Aschoff, H-H; Juhnke, D-L

2016-05-01

In 1999 the first endo-exo femoral prosthesis (EEFP) was implanted in Germany in a patient who had suffered a traumatic above-knee amputation. This procedure involves a skeletally anchored exoprosthetic device that is inserted into the residual femur. The distal part of the implant protrudes transcutaneously and allows attachment to a prosthetic limb which provides direct force transmission to the external prosthetic components. The technique originated from dental implantology and helps to avoid possible problems resulting from treatment of amputated limbs using socket prostheses. In the meantime, durability times of over 10 years have now helped to invalidate the initially well-founded reservations held against the procedure. What advantages can be achieved by osseointegrated and percutaneously channeled prostheses and which problems had to be overcome for treatment. Critical evaluation of data from patients operated on in Lübeck, Germany from January 2003 to December 2014. With osseointegrated and percutaneously channeled prostheses permanent durability times can be achieved. Infection-associated soft tissue problems at the site of skin protrusion (stoma) can be successfully prevented. The creation of this so-called stoma means acceptance of a possible bacterial portal of entry into the body. Patient satisfaction has so far been high, postoperative rehabilitation is simplified and the technique could possibly lower the costs of medical treatment. Endo-exo prostheses have proved to be successful for more than 15 years. A critical appraisal of the indications as well as a close cooperation between the surgeon, orthopedic technician and the associated rehabilitation facilities with the patient are the basis for the long-term success of this relatively new treatment approach.

Comparison of Trapping Performance Between the Original BG-Sentinel® Trap and BG-Sentinel 2® Trap (1).

PubMed

Arimoto, Hanayo; Harwood, James F; Nunn, Peter J; Richardson, Alec G; Gordon, Scott; Obenauer, Peter J

2015-12-01

Recently, the BG-Sentinel® trap (BGS) trap has been reconfigured for increased durability during harsh field conditions. We evaluated the attractiveness of this redesigned trap, BG-Sentinel 2® (BGS2), and its novel granular lure cartridge system relative to the original trap and lure. Granular lures containing different combinations of lactic acid, ammonia, hexanoic acid, and octenol were also evaluated. Lure cartridges with all components except octenol trapped significantly more Aedes albopictus than lures containing octenol. This new granular lure combination and original BG-Lure® system were paired with BGS and BGS2 traps to compare relative attractiveness of the lures and the traps. All evaluations were conducted under field conditions in a suburban neighborhood in northeastern Florida from July to October 2014. Overall, the average numbers of Ae. albopictus collected by BGS or BGS2 were similar regardless of the lure type (i.e., mesh bag versus granules) (P  =  0.56). The functionality and durability of both trap models are discussed.

Debonding damage analysis in composite-masonry strengthening systems with polymer- and mortar-based matrix by means of the acoustic emission technique

NASA Astrophysics Data System (ADS)

Verstrynge, E.; Wevers, M.; Ghiassi, B.; Lourenço, P. B.

2016-01-01

Different types of strengthening systems, based on fiber reinforced materials, are under investigation for external strengthening of historic masonry structures. A full characterization of the bond behavior and of the short- and long-term failure mechanisms is crucial to ensure effective design, compatibility with the historic substrate and durability of the strengthening solution. Therein, non-destructive techniques are essential for bond characterization, durability assessment and on-site condition monitoring. In this paper, the acoustic emission (AE) technique is evaluated for debonding characterization and localization on fiber reinforced polymer (FRP) and steel reinforced grout-strengthened clay bricks. Both types of strengthening systems are subjected to accelerated ageing tests under thermal cycles and to single-lap shear bond tests. During the reported experimental campaign, AE data from the accelerated ageing tests demonstrated the thermal incompatibility between brick and epoxy-bonded FRP composites, and debonding damage was successfully detected, characterized and located. In addition, a qualitative comparison is made with digital image correlation and infrared thermography, in view of efficient on-site debonding detection.

Comparison of iridium- and ruthenium-based, Pt-surface-enriched, nanosize catalysts for the oxygen-reduction reaction

NASA Astrophysics Data System (ADS)

Kaplan, D.; Goor, M.; Alon, M.; Tsizin, S.; Burstein, L.; Rosenberg, Y.; Popov, I.; Peled, E.

2016-02-01

Pt-surface-enriched nanosize catalysts (Pt-SENS catalysts) with ruthenium and iridium cores, supported on XC72, were synthesized and characterized. The structure and composition of the catalysts are determined by Energy-Dispersive X-ray Spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS), Scanning Transmission Electron Microscopy (STEM) and X-Ray Diffraction (XRD). Electrochemical characterization tests, including oxygen-reduction-catalysis activity and durability studies of catalysts are performed with the use of cyclic-voltammetry and rotating-disk-electrode (RDE) techniques at room temperature. The ORR activity of the homemade catalysts is also compared to ORR activity of commercial 50%Pt/C catalyst. It is determined that the Ir-based catalyst (Pt/Ir/XC72) shows higher ORR activity in terms of A g-1 of Pt (at 0.85 V vs. RHE) than the Ru-based catalyst (Pt/Ru/XC72) and the commercial 50%Pt/C. The Ru-based catalyst shows similar ORR activity in terms of A g-1 of Pt, to that of the commercial 50%Pt/C, but with much lower durability.

Depth of Processing and Age Differences.

PubMed

Kheirzadeh, Shiela; Pakzadian, Sarah Sadat

2016-10-01

The present article is aimed to investigate whether there are any differences between youngsters and adults in their working and long-term memory functioning. The theory of Depth of Processing (Craik and Lockhart in J Verbal Learning Verbal Behav 11:671-684, 1972) discusses the varying degrees of strengths of memory traces as the result of differential levels of processing on the retrieved input. Additionally, they claim that there are three levels of visual, auditory and semantic processes applied on the stimuli in the short-term memory leading to discrepancy in the durability of the memory traces and the later ease of recall and retrieval. In the present article, it is tried to demonstrate if there are evidences of more durable memory traces formed after semantic, visual and auditory processions of the incoming language data in two groups of (a) children in their language learning critical age and (b) youngsters who have passed the critical age period. The comparisons of the results made using two-way ANOVAs revealed the superiority of semantic processing for both age groups in recall, retention and consequently recognition of the new English vocabularies by EFL learners.

A porous ceramic membrane tailored high-temperature supercapacitor

NASA Astrophysics Data System (ADS)

Zhang, Xin; He, Benlin; Zhao, Yuanyuan; Tang, Qunwei

2018-03-01

The supercapacitor that can operate at high-temperature are promising for markedly increase in capacitance because of accelerated charge movement. However, the state-of-the-art polymer-based membranes will decompose at high temperature. Inspired by solid oxide fuel cells, we present here the experimental realization of high-temperature supercapacitors (HTSCs) tailored with porous ceramic separator fabricated by yttria-stabilized zirconia (YSZ) and nickel oxide (NiO). Using activated carbon electrode and supporting electrolyte from potassium hydroxide (KOH) aqueous solution, a category of symmetrical HTSCs are built in comparison with a conventional polymer membrane based device. The dependence of capacitance performance on temperature is carefully studied, yielding a maximized specific capacitance of 272 F g-1 at 90 °C for the optimized HTSC tailored by NiO/YSZ membrane. Moreover, the resultant HTSC has relatively high durability when suffer repeated measurement over 1000 cycles at 90 °C, while the polymer membrane based supercapacitor shows significant reduction in capacitance at 60 °C. The high capacitance along with durability demonstrates NiO/YSZ membrane tailored HTSCs are promising in future advanced energy storage devices.

Evaluation of aluminum ultralight rigid wheelchairs versus other ultralight wheelchairs using ANSI/RESNA standards.

PubMed

Liu, Hsin-yi; Pearlman, Jonathan; Cooper, Rosemarie; Hong, Eun-kyoung; Wang, Hongwu; Salatin, Benjamin; Cooper, Rory A

2010-01-01

Previous studies found that select titanium ultralight rigid wheelchairs (TURWs) had fewer equivalent cycles and less value than select aluminum ultralight folding wheelchairs (AUFWs). The causes of premature failure of TURWs were not clear because the TURWs had different frame material and design than the AUFWs. We tested 12 aluminum ultralight rigid wheelchairs (AURWs) with similar frame designs and dimensions as the TURWs using the American National Standards Institute/Rehabilitation Engineering and Assistive Technology Society of North America and International Organization for Standardization wheelchair standards and hypothesized that the AURWs would be more durable than the TURWs. Across wheelchair models, no significant differences were found in the test results between the AURWs and TURWs, except in their overall length. Tire pressure, tube-wall thickness, and tube manufacturing were proposed to be the factors affecting wheelchair durability through comparison of the failure modes, frames, and components. The frame material did not directly affect the performance of AURWs and TURWs, but proper wheelchair manufacture and design based on mechanical properties are important.

Advanced mortar coatings for cultural heritage protection. Durability towards prolonged UV and outdoor exposure.

PubMed

Pino, F; Fermo, P; La Russa, M; Ruffolo, S; Comite, V; Baghdachi, J; Pecchioni, E; Fratini, F; Cappelletti, G

2017-05-01

In the present work, two kinds of hybrid polymeric-inorganic coatings containing TiO 2 or SiO 2 particles and prepared starting from two commercial resins (Alpha®SI30 and Bluesil®BP9710) were developed and applied to two kinds of mortars (an air-hardening calcic lime mortar [ALM] and a natural hydraulic lime mortar [HLM]) to achieve better performances in terms of water repellence and consequently damage resistance. The two pure commercial resins were also applied for comparison purposes. Properties of the coated materials and their performance were studied using different techniques such as contact angle measurements, capillary absorption test, mercury intrusion porosimetry, surface free energy, colorimetric measurements and water vapour permeability tests. Tests were also performed to determine the weathering effects on both the commercial and the hybrid coatings in order to study their durability. Thus, exposures to UV radiation, to UV radiation/condensed water cycles and to a real polluted atmospheric environment have been performed. The effectiveness of the hybrid SiO 2 based coating was demonstrated, especially in the case of the HLM mortar.

Compositional threshold for Nuclear Waste Glass Durability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, Albert A.; Farooqi, Rahmatullah; Hrma, Pavel R.

2013-04-24

Within the composition space of glasses, a distinct threshold appears to exist that separates "good" glasses, i.e., those which are sufficiently durable, from "bad" glasses of a low durability. The objective of our research is to clarify the origin of this threshold by exploring the relationship between glass composition, glass structure and chemical durability around the threshold region.

Microbial Community Analysis of Naturally Durable Wood in an Above Ground Field Test

Treesearch

G.T. Kirker; S.V. Diehl; P.K. Lebow

2014-01-01

This paper presents preliminary results of an above ground field test wherein eight naturally durable wood species were exposed concurrently at two sites in North America. Surface samples were taken at regular intervals from non-durable controls and compared to their more durable counterparts. Terminal Restriction Fragment Length Polymorphism was performed to...

Combined hydrophobicity and mechanical durability through surface nanoengineering

DOE PAGES

Elliott, Paul R.; Stagon, Stephen P.; Huang, Hanchen; ...

2015-04-08

This paper reports combined hydrophobicity and mechanical durability through the nanoscale engineering of surfaces in the form of nanorod-polymer composites. Specifically, the hydrophobicity derives from nanoscale features of mechanically hard ZnO nanorods and the mechanical durability derives from the composite structure of a hard ZnO nanorod core and soft polymer shell. Experimental characterization correlates the morphology of the nanoengineered surfaces with the combined hydrophobicity and mechanical durability, and reveals the responsible mechanisms. Such surfaces may find use in applications, such as boat hulls, that benefit from hydrophobicity and require mechanical durability.

[Method to make the tricuspid extracardiac conduit by heterogeneous pericardium].

PubMed

Yamagishi, M; Imai, Y; Koh, Y; Nagatsu, M; Matsuo, K; Kurosawa, H

1992-07-01

We described here, how to make tricuspid extracardiac conduit by heterogeneous pericardium for Rastelli procedure. We have developed some ingenious devices which allow to obtain good hemodynamics. One of the devices is large valvular leaflets as long as 130% of the circumference of the conduit. Another device is the commissural suture as figure of eight. We used 121 tricuspid extracardiac conduits between January 1985 and March 1991. There were two reoperations: One from stenosis at the suture with ventricle and the other from infective endocarditis. This hand-made conduit has the advantages of flexibility, fitness with the pulmonary artery, wide range of size and very little regurgitation. These advantages indicate that the tricuspid extracardiac conduit made by heterogeneous pericardium is a valved conduit substitute of choice for Rastelli procedure. The durability of the conduit is to be further evaluated.

Percutaneous endoscopic cecostomy (introducer method) in chronic intestinal pseudo-obstruction: Report of two cases and literature review.

PubMed

Küllmer, Armin; Schmidt, Arthur; Caca, Karel

2016-03-01

We report on two patients with recurrent episodes of chronic intestinal pseudo-obstruction (CIPO). A 50-year-old woman with severe multiple sclerosis and an 84-year-old man with Parkinson's disease and dementia had multiple hospital admissions because of pain and distended abdomen. Radiographic and endoscopic findings showed massive dilation of the colon without any evidence of obstruction. Conservative management resolved symptoms only for a short period of time. As these patients were poor candidates for any surgical treatment we carried out percutaneous endoscopic colostomy by placing a 20-Fr tube in the cecum with the introducer method. The procedure led to durable symptom relief without complications. We present these two cases and give a review through the existing literature of the procedure in CIPO. © 2015 Japan Gastroenterological Endoscopy Society.

Polarization of perceived Procedural Justice.

PubMed

Flint, Douglas H; Hernandez-Marrero, Pablo; Wielemaker, Martin

2006-02-01

This study examined polarization of perceptions of Procedural Justice. Two polarization mechanisms are examined, Persuasive Arguments and Social Comparisons. Participants were students enrolled in a first-year introductory business class. There were 216 participants in the Persuasive Arguments study, 429 in the Social Comparisons study. The average age of all participants was 22.3 yr. (SD = 2.1); 56% were women. Fields of study represented were business, engineering, information technology, and sports. Analysis showed under conditions of low Procedural Justice, polarization effects were only found with the Persuasive Arguments mechanism. Under conditions of high Procedural Justice, polarization effects were only found with Social Comparisons. Implications for group polarization and Procedural Justice theories are considered.

Glass science tutorial: Lecture No. 7, Waste glass technology for Hanford

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, A.A.

1995-07-01

This paper presents the details of the waste glass tutorial session that was held to promote knowledge of waste glass technology and how this can be used at the Hanford Reservation. Topics discussed include: glass properties; statistical approach to glass development; processing properties of nuclear waste glass; glass composition and the effects of composition on durability; model comparisons of free energy of hydration; LLW glass structure; glass crystallization; amorphous phase separation; corrosion of refractories and electrodes in waste glass melters; and glass formulation for maximum waste loading.

Experimental study on durability improvement of fly ash concrete with durability improving admixture.

PubMed

Quan, Hong-zhu; Kasami, Hideo

2014-01-01

In order to improve the durability of fly ash concrete, a series of experimental studies are carried out, where durability improving admixture is used to reduce drying shrinkage and improve freezing-thawing resistance. The effects of durability improving admixture, air content, water-binder ratio, and fly ash replacement ratio on the performance of fly ash concrete are discussed in this paper. The results show that by using durability improving admixture in nonair-entraining fly ash concrete, the compressive strength of fly ash concrete can be improved by 10%-20%, and the drying shrinkage is reduced by 60%. Carbonation resistance of concrete is roughly proportional to water-cement ratio regardless of water-binder ratio and fly ash replacement ratio. For the specimens cured in air for 2 weeks, the freezing-thawing resistance is improved. In addition, by making use of durability improving admixture, it is easier to control the air content and make fly ash concrete into nonair-entraining one. The quality of fly ash concrete is thereby optimized.

Research on durability of a concrete continuous rigid frame bridge

NASA Astrophysics Data System (ADS)

Shi, Jing-xian; Ran, Zhi-hong

2018-05-01

The research on the durability of concrete structures has also become one of the most important topics for discussion at international academic institutions and conferences. This paper summarizes and reviews the current research on the durability of bridge structure of the bridge at the index relationship between state lifetime and structure durability. According to the actual situation in this paper on a continuous rigid frame bridge China of Yunnan as an example, this bridge was completed and opened to traffic during the first half of the year, a series of tests are carried out for the durability problem. It is found that all the indicators are good within six months after the bridge opened to traffic, but durability issues should be further studied in future monitoring efforts.

Influence of degradation conditions on dentin bonding durability of three universal adhesives.

PubMed

Sai, Keiichi; Shimamura, Yutaka; Takamizawa, Toshiki; Tsujimoto, Akimasa; Imai, Arisa; Endo, Hajime; Barkmeier, Wayne W; Latta, Mark A; Miyazaki, Masashi

2016-11-01

This study aims to determine dentin bonding durability of universal adhesives using shear bond strength (SBS) tests under various degradation conditions. G-Premio Bond (GP, GC), Scotchbond Universal (SU, 3M ESPE) and All Bond Universal (AB, Bisco) were compared with conventional two-step self-etch adhesive Clearfil SE Bond (SE, Kuraray Noritake Dental). Bonded specimens were divided into three groups of ten, and SBSs with bovine dentin were determined after the following treatments: 1) Storage in distilled water at 37°C for 24h followed by 3000, 10,000, 20,000 or 30,000 thermal cycles (TC group), 2) Storage in distilled water at 37°C for 3 months, 6 months or 1year (water storage, WS group) and 3) Storage in distilled water at 37°C for 24h (control). SE bonded specimens showed significantly higher SBSs than universal adhesives, regardless of TC or storage periods, although AB specimens showed significantly increased SBSs after 30,000 thermal cycles. In comparisons of universal adhesives under control and degradation conditions, SBS was only reduced in SU after 1year of WS. Following exposure of various adhesive systems to degradation conditions of thermal cycling and long term storage, SBS values of adhesive systems varied primarily with degradation period. Although universal adhesives have lower SBSs than the two-step self-etch adhesive SE, the present data indicate that the dentin bonding durability of universal adhesives in self-etch mode is sufficient for clinical use. Copyright © 2016 Elsevier Ltd. All rights reserved.

Durable silver mirror with ultra-violet thru far infra-red reflection

DOEpatents

Wolfe, Jesse D.

2010-11-23

A durable highly reflective silver mirror characterized by high reflectance in a broad spectral range of about 300 nm in the UV to the far infrared (.about.10000 nm), as well as exceptional environmental durability. A high absorptivity metal underlayer is used which prevents the formation of a galvanic cell with a silver layer while increasing the reflectance of the silver layer. Environmentally durable overcoat layers are provided to enhance mechanical and chemical durability and protect the silver layer from corrosion and tarnishing, for use in a wide variety of surroundings or climates, including harsh or extreme environments.

Durable solar mirror films

DOE Office of Scientific and Technical Information (OSTI.GOV)

O'Neill, Mark B.; Henderson, Andrew J.; Hebrink, Timothy J.

The present disclosure generally relates to durable solar mirror films, methods of making durable solar mirror films, and constructions including durable solar mirror films. In one embodiment, the present disclosure relates to a solar mirror film comprising: a multilayer optical film layer including having a coefficient of hygroscopic expansion of less than about 30 ppm per percent relative humidity; and a reflective layer having a coefficient of hygroscopic expansion.

Durable solar mirror films

DOEpatents

O'Neill, Mark B.; Henderson, Andrew J.; Hebrink, Timothy J.; Katare, Rajesh K.; Jing, Naiyong; North, Diane; Peterson, Eric M.

2017-02-14

The present disclosure generally relates to durable solar mirror films, methods of making durable solar mirror films, and constructions including durable solar mirror films. In one embodiment, the present disclosure relates to a solar mirror film comprising: a multilayer optical film layer including having a coefficient of hygroscopic expansion of less than about 30 ppm per percent relative humidity; and a reflective layer having a coefficient of hygroscopic expansion.

Prediction of glass durability as a function of environmental conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C M

1988-01-01

A thermodynamic model of glass durability is applied to natural, ancient, and nuclear waste glasses. The durabilities of over 150 different natural and man-made glasses, including actual ancient Roman and Islamic glasses (Jalame ca. 350 AD, Nishapur 10-11th century AD and Gorgon 9-11th century AD), are compared. Glass durability is a function of the thermodynamic hydration free energy, ..delta..G/sub hyd/, which can be calculated from glass composition and solution pH. The durability of the most durable nuclear waste glasses examined was /approximately/10/sup 6/ years. The least durable waste glass formulations were comparable in durability to the most durable simulated medievalmore » window glasses of /approximately/10/sup 3/ years. In this manner, the durability of nuclear waste glasses has been interpolated to be /approximately/10/sup 6/ years and no less than 10/sup 3/ years. Hydration thermodynamics have been shown to be applicable to the dissolution of glass in various natural environments. Groundwater-glass interactions relative to geologic disposal of nuclear waste, hydration rind dating of obsidians, andor other archeological studies can be modeled, e.g., the relative durabilities of six simulated medieval window glasses have been correctly predicted for both laboratory (one month) and burial (5 years) experiments. Effects of solution pH on glass dissolution has been determined experimentally for the 150 different glasses and can be predicted theoretically by hydration thermodynamics. The effects of solution redox on dissolution of glass matrix elements such as SI and B have shown to be minimal. The combined effects of solution pH and Eh have been described and unified by construction of thermodynamically calculated Pourbaix (pH-Eh) diagrams for glass dissolution. The Pourbaix diagrams have been quantified to describe glass dissolution as a function of environmental conditions by use of the data derived from hydration thermodynamics. 56 refs., 7 figs.« less

Polymeric heart valves for surgical implantation, catheter-based technologies and heart assist devices.

PubMed

Bezuidenhout, Deon; Williams, David F; Zilla, Peter

2015-01-01

Efficient function and long-term durability without the need for anticoagulation, coupled with the ability to be accommodated in many different types of patient, are the principal requirements of replacement heart valves. Although the clinical use of valves appeared to have remained steady for several decades, the evolving demands for the elderly and frail patients typically encountered in the developed world, and the needs of much younger and poorer rheumatic heart disease patients in the developing world have now necessitated new paradigms for heart valve technologies and associated materials. This includes further consideration of durable elastomeric materials. The use of polymers to produce flexible leaflet valves that have the benefits of current commercial bioprosthetic and mechanical valves without any of their deficiencies has been held desirable since the mid 1950s. Much attention has been focused on thermoplastic polyurethanes in view of their generally good physico-chemical properties and versatility in processing, coupled with the improving biocompatibility and stability of recent formulations. Accelerated in vitro durability of between 600 and 1000 million cycles has been achieved using polycarbonate urethanes, and good resistance to degradation, calcification and thrombosis in vivo has been shown with some polysiloxane-based polyurethanes. Nevertheless, polymeric valves have remained relegated to use in temporary ventricular assist devices for bridging heart failure patients to transplantation. Some recent studies suggest that there is a greater degree of instability in thermoplastic materials than hitherto believed so that significant challenges remain in the search for the combination of durability and biocompatibility that would allow polymeric valves to become a clinical reality for surgical implantation. Perhaps more importantly, they could become candidates for use in situations where minimally invasive transcatheter procedures are used to replace diseased valves. Being amenable to relatively inexpensive mass production techniques, the attainment of this goal could benefit very large numbers of patients in developing and emerging countries who currently have no access to treatment for rheumatic heart disease that is so prevalent in these areas. This review discusses the evolution and current status of polymeric valves in wide-ranging circumstances.

Surface evaluation of orthopedic hip implants marketed in Brazil

NASA Astrophysics Data System (ADS)

Souza, M. M.; Trommer, R. M.; Maru, M. M.; Roesler, C. R. M.; Barros, W. S.; Dutra, M. S.

2016-07-01

One of the factors that contribute to the quality of total hip prostheses is the degree of accuracy in the manufacturing of the joint surfaces. The dimensional control of joint components is important because of its direct influence on the durability and, consequently, in the patients’ life quality. This work presents studies on the form and roughness of orthopedic hip prostheses marketed in Brazil. The results provide data for quality control of the surfaces of the femoral heads and acetabular components of hip prostheses and indicate the need of improvement in the procedures used to this control.

Multi-Functional Composite Fatigue

NASA Technical Reports Server (NTRS)

Minnetyan, Levon; Chamis, Christos C.

2008-01-01

Damage and fracture of composites subjected to monotonically increasing static, tension-tension cyclic, pressurization, and flexural cyclic loading are evaluated via a recently developed composite mechanics code that allows the user to focus on composite response at infinitely small scales. Constituent material properties, stress and strain limits are scaled up to the laminate level to evaluate the overall damage and durability. Results show the number of cycles to failure at different temperatures. A procedure is outlined for use of computational simulation data in the assessment of damage tolerance, determination of sensitive parameters affecting fracture, and interpretation of results with insight for design decisions.

Direct and Indirect Pulp Capping: A Brief History, Material Innovations, and Clinical Case Report.

PubMed

Alex, Gary

2018-03-01

Among the goals of pulp capping are to manage bacteria, arrest caries progression, stimulate pulp cells to form new dentin, and produce a durable seal that protects the pulp complex. This article will provide a general discussion of direct and indirect pulp capping procedures, offering practitioners a pragmatic and science-based clinical protocol for treatment of vital pulp exposures. A clinical case will be presented in which a novel light-cured resin-modified mineral trioxide aggregate hybrid material was used to manage a mechanical vital pulp exposure that occurred during deep caries excavation.

Treatment of chronic radiation injury over the shoulder with a latissimus dorsi myocutaneous flap

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mendelson, B.C.; Masson, J.K.

1977-11-01

We report our experiences in treating chronic radiation injury about the shoulder, a complication of radiation after mastectomy. Left untreated, these can result in chronic infection and/or amputation. The coverage of a large shoulder area presents certain unique problems, which severely limit the usefulness of traditional procedures. We have found that the remarkable size and versatility of the latissimus dorsi myocutaneous flap enables one to use it with relative simplicity and safety. A further great advantage is that it brings new permanent blood supply into this ischemic area, thus favoring rapid healing and durable coverage.

Surgical management of Crohn's colitis.

PubMed

Moir, Christopher R

2007-08-01

Crohn's disease in childhood is changing. The incidence is increasing, colonic disease is becoming more prevalent in younger children, and colon reconstruction is more acceptable. Genetic phenotypes are influencing decisions for surgery, and targeted immunotherapy has renewed hope for more durable remissions following less extensive resections. The tasks facing the surgeon evaluating a child with Crohn's colitis include confirming the specific diagnostic subtype and selecting the correct procedure. This chapter will review the unique aspects of pediatric Crohn's colitis and the increased complexity of surgical choice for this most challenging presentation. Recent success with less extensive surgery offers renewed hope for children with intractable colonic disease.

Comparative durability and costs analysis of ventricular shunts.

PubMed

Agarwal, Nitin; Kashkoush, Ahmed; McDowell, Michael M; Lariviere, William R; Ismail, Naveed; Friedlander, Robert M

2018-05-11

OBJECTIVE Ventricular shunt (VS) durability has been well studied in the pediatric population and in patients with normal pressure hydrocephalus; however, further evaluation in a more heterogeneous adult population is needed. This study aims to evaluate the effect of diagnosis and valve type-fixed versus programmable-on shunt durability and cost for placement of shunts in adult patients. METHODS The authors retrospectively reviewed the medical records of all patients who underwent implantation of a VS for hydrocephalus at their institution over a 3-year period between August 2013 and October 2016 with a minimum postoperative follow-up of 6 months. The primary outcome was shunt revision, which was defined as reoperation for any indication after the initial procedure. Supply costs, shunt durability, and hydrocephalus etiologies were compared between fixed and programmable valves. RESULTS A total of 417 patients underwent shunt placement during the index time frame, consisting of 62 fixed shunts (15%) and 355 programmable shunts (85%). The mean follow-up was 30 ± 12 (SD) months. The shunt revision rate was 22% for programmable pressure valves and 21% for fixed pressure valves (HR 1.1 [95% CI 0.6-1.8]). Shunt complications, such as valve failure, infection, and overdrainage, occurred with similar frequency across valve types. Kaplan-Meier survival curve analysis showed no difference in durability between fixed (mean 39 months) and programmable (mean 40 months) shunts (p = 0.980, log-rank test). The median shunt supply cost per index case and accounting for subsequent revisions was $3438 (interquartile range $2938-$3876) and $1504 (interquartile range $753-$1584) for programmable and fixed shunts, respectively (p < 0.001, Wilcoxon rank-sum test). Of all hydrocephalus etiologies, pseudotumor cerebri (HR 1.9 [95% CI 1.2-3.1]) and previous shunt malfunction (HR 1.8 [95% CI 1.2-2.7]) were found to significantly increase the risk of shunt revision. Within each diagnosis, there were no significant differences in revision rates between shunts with a fixed valve and shunts with a programmable valve. CONCLUSIONS Long-term shunt revision rates are similar for fixed and programmable shunt pressure valves in adult patients. Hydrocephalus etiology may play a significant role in predicting shunt revision, although programmable valves incur higher supply costs regardless of initial diagnosis. Utilization of fixed pressure valves versus programmable pressure valves may reduce supply costs while maintaining similar revision rates. Given the importance of developing cost-effective management protocols, this study highlights the critical need for large-scale prospective observational studies and randomized clinical trials of ventricular shunt valve revisions and additional patient-centered outcomes.

Reasons for and Against Use of Non-absorbable, Synthetic Mesh During Pelvic Organ Prolapse Repair, According to the Prolapsed Compartment.

PubMed

Kontogiannis, Stavros; Goulimi, Evangelia; Giannitsas, Konstantinos

2017-01-01

Awareness and reporting of mesh-related complications of pelvic organ prolapse repairs have increased in recent years. As a result, deciding whether to use a mesh or not has become a difficult task for urogynecologists. Our aim was to summarize reasons for and against the use of mesh in prolapse repair based on a review of relevant literature. Scopus and PubMed databases were searched for papers reporting on the efficacy and safety of native tissue versus non-absorbable, synthetic mesh prolapse repairs. Randomized controlled trials, systematic reviews, and meta-analyses were included. Evidence is presented for each vaginal compartment separately. In the anterior compartment, mesh repairs seem to offer clearly superior efficacy and durability of results compared to native tissue repairs, but with an equally clear increase in complication rates. In the isolated posterior compartment prolapse, high-quality evidence is sparse. As far as the apical compartment is concerned, sacrocolpopexy is the most efficacious, yet the most invasive procedure. Data on the comparison of transvaginal mesh versus native tissue repairs of the apical compartment are somewhat ambiguous. Given the inevitable coexistence of advantages and disadvantages of mesh use in each of the prolapsed vaginal compartments, an individualized treatment decision, based on weighing risks against benefits for each patient, seems to be the most rational approach.

Assessing Consequences of Intra-Aortic Balloon Counterpulsation vs. Left Ventricular Assist Devices at the Time of Heart Transplantation

PubMed Central

Castleberry, Anthony W.; DeVore, Adam D.; Southerland, Kevin W.; Meza, James M.; Irish, William D.; Rogers, Joseph G.; Milano, Carmelo A.; Patel, Chetan B.

2016-01-01

The proportion of heart transplant recipients bridged with durable left ventricular assist devices (dLVADs) has dramatically increased; however, concern exists regarding obligate repeat sternotomy, increase bleeding risk due to anticoagulation and acquired von Willebrand disease, and increased rates of allosensitization. Whether dLVAD patients have impaired post-transplant outcomes compared to equivalent patients with less invasive intraaortic balloon counterpulsation (IABP) at the time of transplant is unknown. We therefore analyzed adult, first time, heart-only transplant procedures with dLVAD (n=2,636) compared to IABP (n=571) at the time of transplant based on data from the United Network for Organ Sharing (UNOS) 07/2004 – 12/2011. There was clear geographic variation in IABP and dLVAD at transplant. Multivariable analysis demonstrated equivalent cumulative risk of death (adjusted Cox proportional hazard ratio: 1.08, 95% confidence interval: 0.87 – 1.33, p=0.51). There was no significant difference in adjusted comparison of perioperative morality, length of stay, postoperative renal failure requiring dialysis, or early acute rejection (p≥0.14 for all). Data from UNOS therefore suggests that the presence of dLVAD at the time of heart transplantation does not have a detrimental effect on postoperative outcomes compared to IABP, which must be considered in the context of pre-transplant mortality and locoregional organ availability. PMID:26735554

Development of a high-temperature durable catalyst for use in catalytic combustors for advanced automotive gas turbine engines

NASA Astrophysics Data System (ADS)

Tong, H.; Snow, G. C.; Chu, E. K.; Chang, R. L. S.; Angwin, M. J.; Pessagno, S. L.

1981-09-01

Durable catalytic reactors for advanced gas turbine engines were developed. Objectives were: to evaluate furnace aging as a cost effective catalytic reactor screening test, measure reactor degradation as a function of furnace aging, demonstrate 1,000 hours of combustion durability, and define a catalytic reactor system with a high probability of successful integration into an automotive gas turbine engine. Fourteen different catalytic reactor concepts were evaluated, leading to the selection of one for a durability combustion test with diesel fuel for combustion conditions. Eight additional catalytic reactors were evaluated and one of these was successfully combustion tested on propane fuel. This durability reactor used graded cell honeycombs and a combination of noble metal and metal oxide catalysts. The reactor was catalytically active and structurally sound at the end of the durability test.

Development of a high-temperature durable catalyst for use in catalytic combustors for advanced automotive gas turbine engines

NASA Technical Reports Server (NTRS)

Tong, H.; Snow, G. C.; Chu, E. K.; Chang, R. L. S.; Angwin, M. J.; Pessagno, S. L.

1981-01-01

Durable catalytic reactors for advanced gas turbine engines were developed. Objectives were: to evaluate furnace aging as a cost effective catalytic reactor screening test, measure reactor degradation as a function of furnace aging, demonstrate 1,000 hours of combustion durability, and define a catalytic reactor system with a high probability of successful integration into an automotive gas turbine engine. Fourteen different catalytic reactor concepts were evaluated, leading to the selection of one for a durability combustion test with diesel fuel for combustion conditions. Eight additional catalytic reactors were evaluated and one of these was successfully combustion tested on propane fuel. This durability reactor used graded cell honeycombs and a combination of noble metal and metal oxide catalysts. The reactor was catalytically active and structurally sound at the end of the durability test.

Sustainability and durability analysis of reinforced concrete structures

NASA Astrophysics Data System (ADS)

Horáková, A.; Broukalová, I.; Kohoutková, A.; Vašková, J.

2017-09-01

The article describes an assessment of reinforced concrete structures in terms of durability and sustainable development. There is a short summary of findings from the literature on evaluation methods for environmental impacts and also about corrosive influences acting on the reinforced concrete structure, about factors influencing the durability of these structures and mathematical models describing the corrosion impacts. Variant design of reinforced concrete structure and assessment of these variants in terms of durability and sustainability was performed. The analysed structure was a concrete ceiling structure of a parking house for cars. The variants differ in strength class of concrete and thickness of concrete slab. It was found that in terms of durability and sustainable development it is significantly preferable to use higher class of concrete. There are significant differences in results of concrete structures durability for different mathematical models of corrosive influences.

Micro-measurements of mechanical properties for adhesives and composites using digital imaging technology

NASA Technical Reports Server (NTRS)

Brinson, Hal F.

1994-01-01

The need for a constituent based durability or accelerated life prediction procedure to be used for the engineering design of polymer matrix composites is discussed in the light of current plans for the High Speed Civil Transport (HSCT) concerns about the U.S. infrastructure (bridges, pipelines, etc.) and other technological considerations of national concern. It is pointed out that good measurement procedures for insitu resin properties are needed for both adhesives and composites. A double cantilever beam (DCB) specimen which shows promise for the easy determination of adhesive shear properties is presented and compared with measurements of strains within the bondline using a new optical digital imaging micro-measurement system (DIMMS). The DCB specimen is also used to assess damage in a bonded joint using a dynamic mechanical thermal analysis system (DMTA). The possible utilization of the same DIMMS and DMTA procedures to determine the insitu properties of the resin in a composite specimen are discussed as well as the use of the procedures to evaluate long term mechanical and physical aging. Finally, a discussion on the state-of-the art of the measurement of strains in micron and sub-micron domains is given.

Using Bonding Enamel-Coated Steel Fixtures to Produce More Durable Brick/Masonry Structures

DTIC Science & Technology

2010-02-01

Initial tests with enameled metal straps cracked all the test cylinders and straps would not pull out BUILDING STRONG® New Strong Durable Ties...BUILDING STRONG® Using Bonding Enamel -Coated Steel Fixtures to Produce More Durable Brick/Masonry Structures Principal Investigator: Steven C...COVERED 00-00-2010 to 00-00-2010 4. TITLE AND SUBTITLE Using Bonding Enamel -Coated Steel Fixtures to Produce More Durable Brick/Masonry

A prospective outcomes analysis of palliative procedures performed for malignant intestinal obstruction due to recurrent ovarian cancer.

PubMed

Chi, Dennis S; Phaëton, Rebecca; Miner, Thomas J; Kardos, Steven V; Diaz, John P; Leitao, Mario M; Gardner, Ginger; Huh, Jae; Tew, William P; Konner, Jason A; Sonoda, Yukio; Abu-Rustum, Nadeem R; Barakat, Richard R; Jaques, David P

2009-08-01

To obtain prospective outcomes data on patients (pts) undergoing palliative operative or endoscopic procedures for malignant bowel obstruction due to recurrent ovarian cancer. An institutional study was conducted from July 2002 to July 2003 to prospectively identify pts who underwent an operative or endoscopic procedure to palliate the symptoms of advanced cancer. This report focuses on pts with malignant bowel obstruction due to recurrent ovarian cancer. Procedures performed with an upper or lower gastrointestinal (GI) endoscope were considered "endoscopic." All other cases were classified as "operative." Following the procedure, the presence or absence of symptoms was determined and followed over time. All pts were followed until death. Palliative interventions were performed on 74 gynecologic oncology pts during the study period, of which 26 (35%) were for malignant GI obstruction due to recurrent ovarian cancer. The site of obstruction was small bowel in 14 (54%) cases and large bowel in 12 (46%) cases. Palliative procedures were operative in 14 (54%) pts and endoscopic in the other 12 (46%). Overall, symptomatic improvement or resolution within 30 days was achieved in 23 (88%) of 26 patients, with 1 (4%) postprocedure mortality. At 60 days, 10 (71%) of 14 pts who underwent operative procedures and 6 (50%) of 12 pts who had endoscopic procedures had symptom control. Median survival from the time of the palliative procedure was 191 days (range, 33-902) for those undergoing an operative procedure and 78 days (range, 18-284) for those undergoing an endoscopic procedure. Patients with malignant bowel obstructions due to recurrent ovarian cancer have a high likelihood of experiencing relief of symptoms with palliative procedures. Although recurrence of symptoms is common, durable palliation and extended survival are possible, especially in those patients selected for operative intervention.

Evidence-based outcomes of holmium laser enucleation of the prostate.

PubMed

Large, Tim; Krambeck, Amy E

2018-05-01

Holmium laser enucleation of the prostate (HoLEP) has been a mainstay therapy for the treatment of lower urinary tract symptoms (LUTS) secondary to benign prostate hyperplasia (BPH) for nearly 20 years. We briefly review current and sentinel publications that provide outcomes data after HoLEP. Current literature continues to support HoLEP as a versatile and durable surgical option for men with LUTS secondary to BPH. Despite evidence supporting durable symptom relief beyond 10 years even in large prostate glands, HoLEP is still not widely available to all patients. Concerns surrounding the learning curve of the procedure, high rates of retrograde ejaculation, and transient urinary incontinence seem to persist and limit the adoption of HoLEP by established urologists and residency training programs. Recent publications continue to show excellent short-term and long-term outcomes after HoLEP, in the categories of voiding function and patient satisfaction. Continued attempts to demonstrate equivalent outcomes of alternate-BPH surgical techniques are being met with renewed efforts by those performing HoLEP to demonstrate equivalent outcomes and patient safety during the learning phase of HoLEP for both mentored and self-directed surgical training.

Durability and regeneration of activated carbon air-cathodes in long-term operated microbial fuel cells

NASA Astrophysics Data System (ADS)

Zhang, Enren; Wang, Feng; Yu, Qingling; Scott, Keith; Wang, Xu; Diao, Guowang

2017-08-01

The performance of activated carbon catalyst in air-cathodes in microbial fuel cells was investigated over one year. A maximum power of 1722 mW m-2 was produced within the initial one-month microbial fuel cell operation. The air-cathodes produced a maximum power >1200 mW m-2 within six months, but gradually became a limiting factor for the power output in prolonged microbial fuel cell operation. The maximum power decreased by 55% when microbial fuel cells were operated over one year due to deterioration in activated carbon air-cathodes. While salt/biofilm removal from cathodes experiencing one-year operation increased a limiting performance enhancement in cathodes, a washing-drying-pressing procedure could restore the cathode performance to its original levels, although the performance restoration was temporary. Durable cathodes could be regenerated by re-pressing activated carbon catalyst, recovered from one year deteriorated air-cathodes, with new gas diffusion layer, resulting in ∼1800 mW m-2 of maximum power production. The present study indicated that activated carbon was an effective catalyst in microbial fuel cell cathodes, and could be recovered for reuse in long-term operated microbial fuel cells by simple methods.

Durability of crystalline phase in concrete microstructure modified by the mineral powders: evaluation by nanoindentation tests

NASA Astrophysics Data System (ADS)

Rajczakowska, Magdalena; Łydżba, Dariusz

2016-03-01

This paper presents the nanoindentation investigation of the evolution of concrete microstructure modified by the Internal Crystallization Technology mineral powders. The samples under study were retrieved from a fragment of a circular concrete lining of the vertical mine shaft at a depth of approximately 1,000 m. Due to the aggressive environment and exposure to contaminated water, the internal surface of the structure was deteriorated, decreasing its strength significantly. The mineral powders were applied directly on the surface lining. The specimens were investigated one month, three months and one year after the application of the aforementioned substance in order to verify the time dependence of the strengthening processes and durability of the crystalline phase. The microstructural changes of concrete were assessed with the use of nanoindentation technique. The testing procedure involved including the previously cut specimens in the epoxy resin and grinding and polishing in order to reduce the surface roughness. As a result of the nanoindentation tests the hardness as well as Young's modulus of the material were evaluated. The results were then compared and statistically analyzed. As a consequence, the disintegration time of the crystalline network in the pores of concrete was identified.

Concrete aggregate durability study.

DOT National Transportation Integrated Search

2009-06-01

There are many factors that affect the durability of Portland cement concrete (PCC), including the mix design and the : materials used, the quality of construction, and the environment. Durability is not an intrinsic property of the concrete, but : i...

Research notes : inlaid durable pavement markings : year one.

DOT National Transportation Integrated Search

2004-12-01

Durable pavement markings are becoming more prevalent on primary highways statewide, increasing the safety of the traveling public and the ODOT maintenance personnel responsible for maintaining the striping. Several durable products are now being use...

Your Medicare Coverage: Durable Medical Equipment (DME) Coverage

MedlinePlus

... test, item, or service covered? Go Durable medical equipment (DME) coverage How often is it covered? Medicare ... B (Medical Insurance) covers medically necessary durable medical equipment (DME) that your doctor prescribes for use in ...

Experimental Study on Durability Improvement of Fly Ash Concrete with Durability Improving Admixture

PubMed Central

Quan, Hong-zhu; Kasami, Hideo

2014-01-01

In order to improve the durability of fly ash concrete, a series of experimental studies are carried out, where durability improving admixture is used to reduce drying shrinkage and improve freezing-thawing resistance. The effects of durability improving admixture, air content, water-binder ratio, and fly ash replacement ratio on the performance of fly ash concrete are discussed in this paper. The results show that by using durability improving admixture in nonair-entraining fly ash concrete, the compressive strength of fly ash concrete can be improved by 10%–20%, and the drying shrinkage is reduced by 60%. Carbonation resistance of concrete is roughly proportional to water-cement ratio regardless of water-binder ratio and fly ash replacement ratio. For the specimens cured in air for 2 weeks, the freezing-thawing resistance is improved. In addition, by making use of durability improving admixture, it is easier to control the air content and make fly ash concrete into nonair-entraining one. The quality of fly ash concrete is thereby optimized. PMID:25013870

Durability of an inorganic polymer concrete coating

NASA Astrophysics Data System (ADS)

Wasserman, Kenneth

The objective of the research program reported in this thesis is to evaluate the durability of an inorganic polymer composite coating exposed to freeze/thaw cycling and wet-dry cycling. Freeze/thaw cycling is performed following ASTM D6944-09 Standard Practice for Resistance of Cured Coatings to Thermal Cycling and wet/dry cycling is performed following guidelines set forth in a thesis written by Ronald Garon at Rutgers University. For both sets of experiments, four coating mixture proportions were evaluated. The variables were: silica/alumina ratio, mixing protocol using high shear and normal shear mixing, curing temperatures of 70 and 120 degrees Fahrenheit and use of nano size constituent materials. The mix with highest silica/alumina ratio was designated as Mix 1 and mixes with lower ratios were designated as Mix 2 and Mix 3. Mix 4 had nano silica particles. Four prisms were used for each variable including control that had no coating. The performance of the coating was evaluated using adhesion strength measured using: ASTM D7234 Test Method for Pull-Off Strength of Coatings on Concrete Using Portable Adhesion Testers. Tests were performed after every five consecutive cycles of thermal conditioning and six consecutive cycles of wet-dry exposure. Results from the thermal cycling and wet-dry testing demonstrate that all coating formulations are durable. The minimum adhesion strength was 300 psi even though a relatively weak base concrete surface was chosen for the study. The weak surface was chosen to simulate aged concrete surfaces present in actual field conditions. Due to the inherent nature of the test procedure the variation in test results is high. However, based on the test results, high shear mixer and high temperature curing are not recommended. As expected nano size constituent materials provide better performance.

An industrial design solution for integrating NMR magnetic field sensors into an MRI scanner.

PubMed

Kennedy, Michael; Lee, Yoojin; Nagy, Zoltan

2018-08-01

Neuroimaging research relies on the skills of increasingly multidisciplinary individuals and often requires the installation and use of additional home-built or third-party equipment. The purpose of the present work was the safe, ergonomic, durable, and aesthetically pleasing installation of magnetic field monitoring equipment into a scanner, while keeping the setup compatible with standard operating procedures. An extensive set of steps was required to design a 3D printed solution to install a magnetic field camera into the eight-channel head coil of a 3T MRI scanner. First, the outer surface of the plastic coil housing was recreated into a 3D model, and the installation of the magnetic field sensors around this 3D model was performed in a virtual environment. The 3D printed solution was then assembled and tested for safety, reproducible performance, and image quality. The 3D printed solution holds the probes in stable positions and guides the necessary cables in an organized fashion and away from the volunteer. Assembly is easy and the solution is ergonomic, durable, and safe. We did not find excessive heating in the 3D printed parts, nor in the electronics, that they help to incorporate. The material used interferes minimally with transmit B1+ field. The design met all of the boundary conditions for a durable, safe, cost-effective, attractive, and functional installation. This work will provide the basis for installing the magnetic field sensors into other available head coils, and for designing the experimental setup for projects with varying experimental requirements. Magn Reson Med 80:833-839, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Upper Airway Stimulation for Obstructive Sleep Apnea: Durability of the Treatment Effect at 18 Months.

PubMed

Strollo, Patrick J; Gillespie, M Boyd; Soose, Ryan J; Maurer, Joachim T; de Vries, Nico; Cornelius, Jason; Hanson, Ronald D; Padhya, Tapan A; Steward, David L; Woodson, B Tucker; Verbraecken, Johan; Vanderveken, Olivier M; Goetting, Mark G; Feldman, Neil; Chabolle, Frédéric; Badr, M Safwan; Randerath, Winfried; Strohl, Kingman P

2015-10-01

To determine the stability of improvement in polysomnographic measures of sleep disordered breathing, patient reported outcomes, the durability of hypoglossal nerve recruitment and safety at 18 months in the Stimulation Treatment for Apnea Reduction (STAR) trial participants. Prospective multicenter single group trial with participants serving as their own controls. Twenty-two community and academic sleep medicine and otolaryngology practices. Primary outcome measures were the apnea-hypopnea index (AHI) and the 4% oxygen desaturation index (ODI). Secondary outcome measures were the Epworth Sleepiness Scale (ESS), the Functional Outcomes of Sleep Questionnaire (FOSQ), and oxygen saturation percent time < 90% during sleep. Stimulation level for each participant was collected at three predefined thresholds during awake testing. Procedure- and/or device-related adverse events were reviewed and coded by the Clinical Events Committee. The median AHI was reduced by 67.4% from the baseline of 29.3 to 9.7/h at 18 mo. The median ODI was reduced by 67.5% from 25.4 to 8.6/h at 18 mo. The FOSQ and ESS improved significantly at 18 mo compared to baseline values. The functional threshold was unchanged from baseline at 18 mo. Two participants experienced a serious device-related adverse event requiring neurostimulator repositioning and fixation. No tongue weakness reported at 18 mo. Upper airway stimulation via the hypoglossal nerve maintained a durable effect of improving airway stability during sleep and improved patient reported outcomes (Epworth Sleepiness Scale and Functional Outcomes of Sleep Questionnaire) without an increase of the stimulation thresholds or tongue injury at 18 mo of follow-up. © 2015 Associated Professional Sleep Societies, LLC.

Engine rotor health monitoring: an experimental approach to fault detection and durability assessment

NASA Astrophysics Data System (ADS)

Abdul-Aziz, Ali; Woike, Mark R.; Clem, Michelle; Baaklini, George

2015-03-01

Efforts to update and improve turbine engine components in meeting flights safety and durability requirements are commitments that engine manufacturers try to continuously fulfill. Most of their concerns and developments energies focus on the rotating components as rotor disks. These components typically undergo rigorous operating conditions and are subject to high centrifugal loadings which subject them to various failure mechanisms. Thus, developing highly advanced health monitoring technology to screen their efficacy and performance is very essential to their prolonged service life and operational success. Nondestructive evaluation techniques are among the many screening methods that presently are being used to pre-detect hidden flaws and mini cracks prior to any appalling events occurrence. Most of these methods or procedures are confined to evaluating material's discontinuities and other defects that have mature to a point where failure is eminent. Hence, development of more robust techniques to pre-predict faults prior to any catastrophic events in these components is highly vital. This paper is focused on presenting research activities covering the ongoing research efforts at NASA Glenn Research Center (GRC) rotor dynamics laboratory in support of developing a fault detection system for key critical turbine engine components. Data obtained from spin test experiments of a rotor disk that relates to investigating behavior of blade tip clearance, tip timing and shaft displacement based on measured data acquired from sensor devices such as eddy current, capacitive and microwave are presented. Additional results linking test data with finite element modeling to characterize the structural durability of a cracked rotor as it relays to the experimental tests and findings is also presented. An obvious difference in the vibration response is shown between the notched and the baseline no notch rotor disk indicating the presence of some type of irregularity.

Evaluation of inlaid durable pavement markings in an Oregon snow zone.

DOT National Transportation Integrated Search

2006-04-01

The Oregon Department of Transportation (ODOT) evaluated the use of inlaid durable pavement markings within a snow zone. Three different durable pavement marking products were installed and evaluated: Dura-Stripe, a methyl methacrylate; Permaline...

Durability of Waste Glass Flax Fiber Reinforced Mortar

NASA Astrophysics Data System (ADS)

Aly, M.; Hashmi, M. S. J.; Olabi, A. G.; Messeiry, M.

2011-01-01

The main concern for natural fibre reinforced mortar composites is the durability of the fibres in the alkaline environment of cement. The composites may undergo a reduction in strength as a result of weakening of the fibres by a combination of alkali attack and fibre mineralisation. In order to enhance the durability of natural fiber reinforced cement composites several approaches have been studied including fiber impregnation, sealing of the matrix pore system and reduction of matrix alkalinity through the use of pozzolanic materials. In this study waste glass powder was used as a pozzolanic additive to improve the durability performance of flax fiber reinforced mortar (FFRM). The durability of the FFRM was studied by determining the effects of ageing in water and exposure to wetting and drying cycles; on the microstructures and flexural behaviour of the composites. The mortar tests demonstrated that the waste glass powder has significant effect on improving the durability of FFRM.

Durable superhydrophobic and superamphiphobic polymeric surfaces and their applications: A review.

PubMed

Ellinas, Kosmas; Tserepi, Angeliki; Gogolides, Evangelos

2017-12-01

Wetting control is essential for many applications, such as self-cleaning, anti-icing, anti-fogging, antibacterial action as well as anti-reflection and friction control. While significant effort has been devoted to fabricate superhydrophobic/superamphiphobic surfaces (repellent to water and other low surface tension liquids), very few polymeric superhydrophobic/superamphiphobic surfaces can be considered as durable against various externally imposed stresses (e.g. application of heating, pressure, mechanical forces, chemical, etc.). Therefore, durability tests are extremely important for applications especially when such surfaces are made of "soft" materials. Here, we review the most recent and promising efforts reported towards the realization of durable, superhydrophobic/superamphiphobic, polymeric surfaces emphasizing the durability tests performed, and some important applications. We compare and put in context the scattered durability tests reported in the literature, and present conclusions, perspectives and challenges in the field. Copyright © 2017 Elsevier B.V. All rights reserved.

Modeling the Rate-Dependent Durability of Reduced-Ag SAC Interconnects for Area Array Packages Under Torsion Loads

NASA Astrophysics Data System (ADS)

Srinivas, Vikram; Menon, Sandeep; Osterman, Michael; Pecht, Michael G.

2013-08-01

Solder durability models frequently focus on the applied strain range; however, the rate of applied loading, or strain rate, is also important. In this study, an approach to incorporate strain rate dependency into durability estimation for solder interconnects is examined. Failure data were collected for SAC105 solder ball grid arrays assembled with SAC305 solder that were subjected to displacement-controlled torsion loads. Strain-rate-dependent (Johnson-Cook model) and strain-rate-independent elastic-plastic properties were used to model the solders in finite-element simulation. Test data were then used to extract damage model constants for the reduced-Ag SAC solder. A generalized Coffin-Manson damage model was used to estimate the durability. The mechanical fatigue durability curve for reduced-silver SAC solder was generated and compared with durability curves for SAC305 and Sn-Pb from the literature.

Cost effectiveness of introducing a new European evaporative emissions test procedure for petrol vehicles

NASA Astrophysics Data System (ADS)

Haq, Gary; Martini, Giorgio; Mellios, Giorgos

2014-10-01

Evaporative emissions of non-methane volatile organic compounds (NMVOCs) arise from the vehicle's fuel system due to changes in ambient and vehicle temperatures, and contribute to urban smog. This paper presents an economic analysis of the societal costs and benefits of implementing a revised European evaporative emission test procedure for petrol vehicles under four scenarios for the period 2015-2040. The paper concludes that the most cost-effective option is the implementation of an aggressive purging strategy over 48 h and improved canister durability (scenario 2+). The average net benefit of implementing this scenario is €146,709,441 at a 6% discount rate. Per vehicle benefits range from €6-9 but when fuel savings benefits are added, total benefits range from €13-18. This is compared to average additional cost per vehicle of €9.

Vital pulp therapy with bipolar electrocoagulation after intentional pulp exposure of fixed prosthodontic abutments: a clinical report.

PubMed

Livaditis, G J

2001-10-01

A clinical protocol is described for the treatment of intentional and unavoidable exposed pulps during crown preparation. The protocol includes a definitive cavity preparation to create space in the exposed dentin for an adhesive pulp barrier; procedures to develop the highly desirable hybrid zone to prevent microleakage; the use of a specific resinous material that serves as a long-term pulp barrier with a relatively neutral and biocompatible impact on the pulp; and the use of precise bipolar electrocoagulation to provide durable hemostasis for restoration of the pulp wall and a relatively clot-free surgical wound to facilitate healing. The protocol involves the application of gentle surgical and restorative procedures to support the inherent healing process to restore the health of the pulp. The patient presented was part of a larger investigation and was selected in an attempt to identify a fixed prosthodontic application of the proposed pulp therapy protocol.

Chitosan-based microcapsules containing grapefruit seed extract grafted onto cellulose fibers by a non-toxic procedure.

PubMed

Alonso, Diana; Gimeno, Miquel; Sepúlveda-Sánchez, José D; Shirai, Keiko

2010-04-19

A novel non-toxic procedure is described for the grafting of chitosan-based microcapsules containing grapefruit seed oil extract onto cellulose. The cellulose was previously UV-irradiated and then functionalized from an aqueous emulsion of the chitosan with the essential oil. The novel materials are readily attained with durable fragrance and enhanced antimicrobial properties. The incorporation of chitosan as determined from the elemental analyses data was 16.08+/-0.29 mg/g of sample. Scanning electron microscopy (SEM) and gas chromatography-mass spectroscopy (GC-MS) provided further evidence for the successful attachment of chitosan microcapsules containing the essential oil to the treated cellulose fibers. The materials thus produced displayed 100% inhibition of Escherichia coli and Staphylococcus epidermidis up to 48 h of incubation. Inhibition of bacteria by the essential oil was also evaluated at several concentrations. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Synthesis of ‘reactive’ and covalent polymeric multilayer coatings with durable superoleophobic and superoleophilic properties under water† †Electronic supplementary information (ESI) available: Fig. S1–S15 accounting the growth of NC with and without the LbL deposition process, detailed comparisons of the multilayers of BPEI and NC, the change in the underwater oil-wettability with increasing deposition cycles of NC, the change in the optical transparency of the multilayers under water, the underwater oil-wettability of various model oils on post-modified multilayers of NC, bouncing of oil droplets underwater, the change in adhesive interactions with LbL deposition of NC, beading and wetting of oil droplets on post-modified multilayers under water, the effect of heating, freezing, and chemical and physical insults on the oil-wettability of the multilayers under water, LbL coating of various substrates, the guided transfer of oil droplets under water and the cleaning of oil using superoleophilic cotton under water. See DOI: 10.1039/c7sc01055a Click here for additional data file.

PubMed Central

Parbat, Dibyangana

2017-01-01

Bioinspired underwater super-oil-wettability (superoleophilic/superoleophobic) properties are emerging as a potential avenue for developing smart materials for addressing issues related to healthcare, environment, energy, etc. However, the inherent poor durability of the materials that are mostly developed using polymeric hydrogel, metal oxide coatings and electrostatic multilayers often challenges the application of these wettability properties in practical scenarios. Here, ‘amine-reactive’ polymeric multilayers of nano-complex were developed to fabricate ‘internal’ underwater superoleophobic/superoleophilic coatings with impeccable physical/chemical durability. This allows the super-wetting properties to exist beyond the surface of the material and remain intact even after severe physical damage including erosion of the material and continuous exposure to an artificial-marine environment for more than 80 days. Moreover, this current design allowed for independent revalidation of some key hypotheses with direct experimental demonstrations, and provided a basis to develop highly durable super-oil-wettability properties under water. It is believed that this contemporary study will make a worthwhile contribution on developing multifunctional materials for widespread practical applications by exploiting these super-oil-wetting properties. PMID:28989639

[The study of carbonaceous adsorbent for solid-phase microextraction and the comparison with commercial device].

PubMed

Fang, R; Zhang, W; Wang, J; Zhang, K; Nai, Z

1999-09-01

The parameters governing solid-phase microextraction have been investigated, and the development of carbonaceous adsorbent for SPME is presented because it is durable and inexpensive. The time profile curves were determined for several organic pesticides having a wide range of water solubilities and the effect of salt was also investigated. The method of SPME-GC-ECD to analyse trace level of the organic pesticide in water is established by the determination of optimum parameters. The comparison with commercial SPME device shows that the carbonaceous adsorbent having been treated with physical or chemical method for SPME can get lower limits of detection than polyacrylate and polydimethylsiloxane, although there are still some work to be done to improve its precision. The results shows that this new SPME device has great application potential.

Mid- and long-term outcomes of carotid-cavernous fistula endovascular management with Onyx and n-BCA: experience of a single tertiary center.

PubMed

Barber, Sean M; Rangel-Castilla, Leonardo; Zhang, Y Jonathan; Klucznik, Richard; Diaz, Orlando

2015-10-01

Endovascular therapy is the preferred treatment for most carotid-cavernous fistulas (CCFs). Early reports have documented excellent initial clinical and radiographic outcomes after embolization of CCFs with Onyx or n-butyl cyanoacrylate (n-BCA), but little evidence is available about the long-term durability of this technique. To characterize the long-term durability of CCF liquid embolization. The authors retrospectively reviewed a database of 24 CCFs in 21 consecutive patients who underwent Onyx or n-BCA embolization of a CCF from 2006 to 2013 at our institution. A total of 25 Onyx or n-BCA embolization procedures were attempted and 24 successfully completed during the study, resulting in complete or near-complete occlusion by the end of the study in all 24 CCFs (obliteration success, 100%). Attempted embolization in a single CCF failed initially, but was performed successfully at a later date by a different approach. None of the 24 CCFs recanalized, regrew, or required any further treatment subsequent to Onyx or n-BCA embolization throughout a mean 12.4 months of angiographic follow-up (range 1-36 months). Clinically significant complications were seen in three embolization procedures, including cranial nerve palsies (n=1), embolic infarct (n=1), and intraperitoneal hemorrhage (n=1). Early evidence has indicated that endovascular embolization with Onyx is relatively safe and effective at achieving an initial angiographic cure for CCFs. Results of our series suggest that angiographic and clinical outcomes of Onyx and n-BCA embolization remain stable at mid- and long-term follow-up. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Ablation of Rotor and Focal Sources Reduces Late Recurrence of Atrial Fibrillation Compared to Trigger Ablation Alone

PubMed Central

Narayan, Sanjiv M.; Baykaner, Tina; Clopton, Paul; Schricker, Amir; Lalani, Gautam; Krummen, David E.; Shivkumar, Kalyanam; Miller, John M.

2014-01-01

Objectives To determine if ablation that targets patient-specific AF-sustaining substrates (rotors or focal sources) is more durable than trigger ablation alone at preventing late AF recurrences. Background Late recurrence substantially limits the efficacy of pulmonary vein (PV) isolation for AF, and is associated with PV reconnection and the emergence of new triggers. Methods We performed 3 year follow-up of the CONFIRM trial, in which 92 consecutive AF patients (70.7% persistent) underwent novel computational mapping to reveal a median of 2 (IQR 1–2) rotors or focal sources in 97.7% of patients during AF. Ablation comprised source (Focal Impulse and Rotor Modulation, FIRM) then conventional ablation in n=27 (FIRM-guided), and conventional ablation alone in n=65 (FIRM-blinded). Patients were followed with implanted ECG monitors when possible (85.2% FIRM guided, 23.1% FIRM-blinded). Results On 890 days follow-up (median; IQR 224–1563) compared FIRM-blinded therapy, patients receiving FIRM-guided ablation maintained higher freedom from AF after 1.2±0.4 procedures (median 1, IQR 1–1) (77.8% vs 38.5%; p=0.001) and a single procedure (p>0.001), and higher freedom from all atrial arrhythmias (p=0.003). Freedom from AF was higher when ablation directly or coincidentally passed through sources than when it missed sources (p>0.001). CONCLUSIONS FIRM-guided ablation is more durable than conventional trigger-based ablation at preventing 3 year AF recurrence. Future studies should investigate how ablation of patient-specific AF-sustaining rotors and focal sources alters the natural history of arrhythmia recurrence. PMID:24632280

Long-Term Endovascular Treatment Outcome of 46 Patients with Cavernous Sinus Dural Arteriovenous Fistulas Presenting with Ophthalmic Symptoms

PubMed Central

Pashapour, Ali; Mohammadian, Reza; Salehpour, Firooz; Sharifipour, Ehsan; Mansourizade, Reza; Mahdavifard, Ali; Salehi, Mohamadgharib; Mirzaii, Farhad; Sariaslani, Payam; Fatahzade Ardalani, Ghasem; Altafi, Davar

2014-01-01

Summary Ocular symptoms are regularly observed in patients with cavernous sinus dural arteriovenous fistulas (cDAVF). We aimed to evaluate the long-term efficacy and safety of endovascular approaches in patients with cDAVF presenting with different ocular symptoms. In a prospective study between June 2008 and March 2013, 46 patients with ocular symptoms due to cDAVF who were not eligible for conservative therapy, met the inclusion criteria and underwent endovascular treatment. They underwent a transarterial approach with histoacryl glue injections or transvenous coil embolization, all in one session. They were followed up for a mean period of 17.3 months (range 7 to 30 months) clinically and using angiography. The mean age of patients was 36.8 years (18-60) and 65% of them were male. All patients showed venous drainage into the superior and inferior orbital veins. Access to the cavernous sinus was transvenous in ten patients, transarterial in 26 patients, and mixed in ten patients. Initial symptoms were improved in 97.8% of patients and did not recur during the study follow-up. The procedural complications included: blurred vision, transient sixth nerve palsy and exacerbation of chemoproptosis in two, one and two patients respectively that completely resolved in initial weeks with no recurrence. No patient worsened or developed new symptoms suggestive of a recurrent fistula during the follow-up period. One patient experienced intracranial dissection of the internal carotid artery and ischemic stroke with an unfinished procedure. The relief of early presentation was durable in long-term follow-up and the cured lesions were stable in angiographic controls. Favorable and durable outcomes could be obtained following endovascular approaches for cDAVF presenting with different ocular symptoms. PMID:25196621

Consumption of a durable termite bait matrix by subterranean termites (Isoptera: Rhinotermitidae) and resulting insecticidal activity.

PubMed

Hamm, Ronda L; DeMark, Joseph J; Chin-Heady, Eva; Tolley, Mike P

2013-04-01

A novel durable termite bait was developed to enable continuous bait availability and lengthen the monitoring interval to 1 year. Laboratory studies were conducted to determine the palatability and insecticidal activity of this bait to Reticulitermes flavipes (Kollar), R. virginicus (Banks), R. hesperus Banks, Coptotermes formosanus Shiraki and Heterotermes aureus (Synder). Consumption of the blank durable bait matrix was significantly higher than consumption of a blank preferred textured cellulose matrix (PTC) by R. virginicus, R. flavipes and C. formosanus. R. flavipes, R. hesperus and H. aureus consumed significantly more durable bait than PTC when both contained the active ingredient noviflumuron. All bait treatments resulted in significant mortality relative to the untreated controls. Survivorship of R. virginicus, C. formosanus and H. aureus was 2% or less and not significantly different between the durable bait and PTC treatments containing noviflumuron. The durable bait matrix lagged behind the PTC matrix in mortality over time for all species tested except H. aureus. The durable bait was highly palatable and effective in inducing mortality to R. flavipes, R. virginicus, R. hesperus, C. formosanus and H. aureus in the laboratory. This unique bait matrix will be available to termites continuously and allows for an annual monitoring interval. The durability of this bait matrix is unprecedented, allowing for bait to remain active for years and thus providing continuous structural protection. © 2012 Society of Chemical Industry.

Unanticipated Effects of New Drug Availability on Antiretroviral Durability: Implications for Comparative Effectiveness Research

PubMed Central

Eaton, Ellen F.; Tamhane, Ashutosh R.; Burkholder, Greer A.; Willig, James H.; Saag, Michael S.; Mugavero, Michael J.

2016-01-01

Background. Durability of antiretroviral (ARV) therapy is associated with improved human immunodeficiency virus (HIV) outcomes. Data on ARV regimen durability in recent years and clinical settings are lacking. Methods. This retrospective follow-up study included treatment-naive HIV-infected patients initiating ARV therapy between January 2007 and December 2012 in a university-affiliated HIV clinic in the Southeastern United States. Outcome of interest was durability (time to discontinuation) of the initial regimen. Durability was evaluated using Kaplan-Meier survival analyses. Cox proportional hazard analyses was used to evaluate the association among durability and sociodemographic, clinical, and regimen-level factors. Results. Overall, 546 patients were analyzed. Median durability of all regimens was 39.5 months (95% confidence interval, 34.1–44.4). Commonly prescribed regimens were emtricitabine and tenofovir with efavirenz (51%; median duration = 40.1 months) and with raltegravir (14%; 47.8 months). Overall, 67% of patients had an undetectable viral load at the time of regimen cessation. Discontinuation was less likely with an integrase strand transfer inhibitor (adjusted hazards ratio [aHR] = 0.35, P = .001) or protease inhibitor-based regimen (aHR = 0.45, P = .006) and more likely with a higher pill burden (aHR = 2.25, P = .003) and a later treatment era (aHR = 1.64, P < .001). Conclusions. Initial ARV regimen longevity declined in recent years contemporaneous with the availability of several new ARV drugs and combinations. Reduced durability mostly results from a preference for newly approved regimens rather than indicating failing therapy, as indicated by viral suppression observed in a majority of patients (67%) prior to regimen cessation. Durability is influenced by extrinsic factors including new drug availability and provider preference. Medication durability must be interpreted carefully in the context of a dynamic treatment landscape. PMID:27419181

Durability assessment of coarse aggregates for HMA in Maine.

DOT National Transportation Integrated Search

2012-12-01

In this study, Micro-Deval and L.A. Abrasion were used to evaluate the durability of 72 individual : coarse aggregates used for HMA in Maine. Aggregates used in hot-mix asphalt (HMA) must be : durable and resistant to abrasion and degradation. Materi...

40 CFR 86.094-13 - Light-duty exhaust durability programs.

Code of Federal Regulations, 2010 CFR

2010-07-01

... requirements. (5) In-use verification. The Standard Self-Approval Durability Program includes no requirement... selection methods, durability data vehicle compliance requirements, in-use verification requirements... Accumulation Carryover. Light-duty Trucks Tier 1 & Tier 0 Standard Self-Approval Carryover. Alternative Service...

Chemical Durability Improvement and Static Fatigue of Glasses.

DTIC Science & Technology

1982-08-01

Afl-Alla 837 RENSSELAER POLYIECmfJ!C INST TRtOY NY DEPT OF MATERIAL--ETC F/6 ii/ CHEMICAL DURABILITY IMPROVEMENT AND STATIC FATIGUE OF GLASSESW AUC2...82 M TOMOZAWA NOGGIN 7A-C-0315 UNC LASS IF IED N ENEEEEEE FINAL TECHNICAL REPORT For the period April 1, 1978 "u March 31, 198200 CHEMICAL DURABILITY...REPORT A PERIOD COVERED Chemical Durability Improvement and Static Final Technical Report Fatiue o GlasesApril 1, 1978"’,March 31, 1982 S. PERFORMING ORG

Durability of high performance concrete in magnesium brine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tumidajski, P.J.; Chan, G.W.

1996-04-01

The durability of six concretes exposed to magnesium brine was monitored for 24 months. These concretes incorporated ground granulated blast furnace slag, silica fume, and fly ash. The Young`s moduli, chloride penetrations, and median pore diameters were measured. There was a cyclic nature to these properties due to the complicated interaction of hydration with magnesium, chloride and sulfate attack. Mineral admixtures, in combination with a long initial cure, provided the most durable concrete. Concrete with 65% slag had the best overall durability to the brines tested.

Genetic Markers Predict Primary Non-Response and Durable Response To Anti-TNF Biologic Therapies in Crohn's Disease.

PubMed

Barber, Grant E; Yajnik, Vijay; Khalili, Hamed; Giallourakis, Cosmas; Garber, John; Xavier, Ramnik; Ananthakrishnan, Ashwin N

2016-12-01

One-fifth of patients with Crohn's disease (CD) are primary non-responders to anti-tumor necrosis factor (anti-TNF) therapy, and an estimated 10-15% will fail therapy annually. Little is known about the genetics of response to anti-TNF therapy. The aim of our study was to identify genetic factors associated with primary non-response (PNR) and loss of response to anti-TNFs in CD. From a prospective registry, we characterized the response of 427 CD patients to their first anti-TNF therapy. Patients were designated as achieving primary response, durable response, and non-durable response based on clinical, endoscopic, and radiologic criteria. Genotyping was performed on the Illumina Immunochip. Separate genetic scores based on presence of predictive genetic alleles were calculated for PNR and durable response and performance of clinical and genetics models were compared. From 359 patients, 36 were adjudged to have PNR (10%), 200 had durable response, and 74 had non-durable response. PNRs had longer disease duration and were more likely to be smokers. Fifteen risk alleles were associated with PNR. Patients with PNR had a significantly higher genetic risk score (GRS) (P =8 × 10 -12 ). A combined clinical-genetic model more accurately predicted PNR when compared with a clinical only model (0.93 vs. 0.70, P <0.001). Sixteen distinct single nucleotide polymorphisms predicted durable response with a higher GRS (P =7 × 10 -13 ). The GRSs for PNR and durable response were not mutually correlated, suggesting distinct mechanisms. Genetic risk alleles can predict primary non-response and durable response to anti-TNF therapy in CD.

Long‐term Outcomes of Catheter Ablation of Atrial Fibrillation: A Systematic Review and Meta‐analysis

PubMed Central

Ganesan, Anand N.; Shipp, Nicholas J.; Brooks, Anthony G.; Kuklik, Pawel; Lau, Dennis H.; Lim, Han S.; Sullivan, Thomas; Roberts‐Thomson, Kurt C.; Sanders, Prashanthan

2013-01-01

Background In the past decade, catheter ablation has become an established therapy for symptomatic atrial fibrillation (AF). Until very recently, few data have been available to guide the clinical community on the outcomes of AF ablation at ≥3 years of follow‐up. We aimed to systematically review the medical literature to evaluate the long‐term outcomes of AF ablation. Methods and Results A structured electronic database search (PubMed, Embase, Web of Science, Cochrane) of the scientific literature was performed for studies describing outcomes at ≥3 years after AF ablation, with a mean follow‐up of ≥24 months after the index procedure. The following data were extracted: (1) single‐procedure success, (2) multiple‐procedure success, and (3) requirement for repeat procedures. Data were extracted from 19 studies, including 6167 patients undergoing AF ablation. Single‐procedure freedom from atrial arrhythmia at long‐term follow‐up was 53.1% (95% CI 46.2% to 60.0%) overall, 54.1% (95% CI 44.4% to 63.4%) in paroxysmal AF, and 41.8% (95% CI 25.2% to 60.5%) in nonparoxysmal AF. Substantial heterogeneity (I2>50%) was noted for single‐procedure outcomes. With multiple procedures, the long‐term success rate was 79.8% (95% CI 75.0% to 83.8%) overall, with significant heterogeneity (I2>50%).The average number of procedures per patient was 1.51 (95% CI 1.36 to 1.67). Conclusions Catheter ablation is an effective and durable long‐term therapeutic strategy for some AF patients. Although significant heterogeneity is seen with single procedures, long‐term freedom from atrial arrhythmia can be achieved in some patients, but multiple procedures may be required. PMID:23537812

Damage Resistance of Titanium Aluminide Evaluated

NASA Technical Reports Server (NTRS)

Lerch, Bradley A.; Draper, Susan L.; Baaklini, George Y.; Pereira, J. Michael; Austin, Curt

2000-01-01

As part of the aviation safety goal to reduce the aircraft accident rate, NASA has undertaken studies to develop durable engine component materials. One of these materials, g-TiAl, has superior high-temperature material properties. Its low density provides improved specific strength and creep resistance in comparison to currently used titanium alloys. However, this intermetallic is inherently brittle, and long life durability is a potential problem. Of particular concern is the material s sensitivity to defects, which may form during the manufacturing process or in service. To determine the sensitivity of TiAl to defects, a team consisting of GE Aircraft Engines, Precision Cast Parts, and NASA was formed. The work at the NASA Glenn Research Center at Lewis Field has concentrated on the fatigue response to specimens containing defects. The overall objective of this work is to determine the influence of defects on the high cycle fatigue life of TiAl-simulated low-pressure turbine blades. Two types of defects have been introduced into the specimens: cracking from impact damage and casting porosity. For both types of defects, the cast-to-size fatigue specimens were fatigue tested at 650 C and 100 Hz until failure.

Dynamic impact testing of hedgehog spines using a dual-arm crash pendulum.

PubMed

Swift, Nathan B; Hsiung, Bor-Kai; Kennedy, Emily B; Tan, Kwek-Tze

2016-08-01

Hedgehog spines are a potential model for impact resistant structures and material. While previous studies have examined static mechanical properties of individual spines, actual collision tests on spines analogous to those observed in the wild have not previously been investigated. In this study, samples of roughly 130 keratin spines were mounted vertically in thin substrates to mimic the natural spine layout on hedgehogs. A weighted crash pendulum was employed to induce and measure the effects of repeated collisions against samples, with the aim to evaluate the influence of various parameters including humidity effect, impact energy, and substrate hardness. Results reveal that softer samples-due to humidity conditioning and/or substrate material used-exhibit greater durability over multiple impacts, while the more rigid samples exhibit greater energy absorption performance at the expense of durability. This trend is exaggerated during high-energy collisions. Comparison of the results to baseline tests with industry standard impact absorbing foam, wherein the spines exhibit similar energy absorption, verifies the dynamic impact absorption capabilities of hedgehog spines and their candidacy as a structural model for engineered impact technology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of Parental Satisfaction with Three Tooth-Colored Full-Coronal Restorations in Primary Maxillary Incisors.

PubMed

Salami, A; Walia, T; Bashiri, R

2015-01-01

To evaluate and compare the parental satisfaction among resin composite strip crown, preveneered stainless steel crown (PVSSC) and the newly introduced pre-fabricated primary zirconia crown for restoring maxillary primary incisors. A prospective clinical study on 39 children with carious or traumatized primary maxillary incisors. They were randomly and equally distributed in three groups and received one of the full-coronal restorations. Children were recalled to evaluate and compare parental satisfaction about performance of crowns after one year through a questionnaire. Parents were satisfied with all three tooth colored full-coronal restoration techniques. A significant relationship was found between colour of PVSSC (p=0.003) and durability of resin strip crowns (p=0.009) with the overall parental satisfaction levels. Parents who gave poor ratings in these two variables however rated their overall acceptance levels as being satisfied. Parental overall satisfaction was highest for zirconia primary crowns followed by resin composite strip crowns and lowest satisfaction was reported for pre-veneered SSCs. Parents were least satisfied with durability of resin composite strip crowns and colour of pre-veneered stainless steel crowns. However, this did not affect their overall satisfaction with these crowns.

Simulation of the low earth orbital atomic oxygen interaction with materials by means of an oxygen ion beam

NASA Technical Reports Server (NTRS)

Banks, Bruce A.; Rutledge, Sharon K.; Paulsen, Phillip E.; Steuber, Thomas J.

1989-01-01

Atomic oxygen is the predominant species in low-Earth orbit between the altitudes of 180 and 650 km. These highly reactive atoms are a result of photodissociation of diatomic oxygen molecules from solar photons having a wavelength less than or equal to 2430A. Spacecraft in low-Earth orbit collide with atomic oxygen in the 3P ground state at impact energies of approximately 4.2 to 4.5 eV. As a consequence, organic materials previously used for high altitude geosynchronous spacecraft are severely oxidized in the low-Earth orbital environment. The evaluation of materials durability to atomic oxygen requires ground simulation of this environment to cost effectively screen materials for durability. Directed broad beam oxygen sources are necessary to evaluate potential spacecraft materials performance before and after exposure to the simulated low-Earth orbital environment. This paper presents a description of a low energy, broad oxygen ion beam source used to simulate the low-Earth orbital atomic oxygen environment. The results of materials interaction with this beam and comparison with actual in-space tests of the same meterials will be discussed. Resulting surface morphologies appear to closely replicate those observed in space tests.

Out of hospital point of care ultrasound: current use models and future directions.

PubMed

Nelson, B P; Sanghvi, A

2016-04-01

Ultrasound has evolved from a modality that was once exclusively reserved to certain specialities of its current state, in which its portability and durability lend to its broadly increasing applications. This review describes portable ultrasound in the hospital setting and its comparison to gold standard imaging modalities. Also, this review summarizes current literature describing portable ultrasound use in prehospital, austere and remote environments, highlighting successes and barriers to use in these environments. Prehospital ultrasound has the ability to increase diagnostic ability and allow for therapeutic intervention in the field. In austere environments, ultrasound may be the only available imaging modality and thus can guide diagnosis, therapeutics and determine which patients may need emergent transfer to a healthcare facility. The most cutting edge applications of portable ultrasound employ telemedicine to obtain and transmit ultrasound images. This technology and ability to transmit images via satellite and cellular transmission can allow for even novice users to obtain interpretable images in austere environments. Portable ultrasound uses have steadily grown and will continue to do so with the introduction of more portable and durable technologies. As applications continue to grow, certain technologic considerations and future directions are explored.

Survey of coatings for solar collectors. [ceramic enamels and chromium

NASA Technical Reports Server (NTRS)

Mcdonald, G. E.

1974-01-01

Ceramic enamel is found to be more solar selective, (i.e., has high solar absorptance in combination with low infrared emittance) than organic enamel, but neither is as solar selective as black chrome, black copper, black zinc, or black nickel. Ceramic enamel is matched only by black chrome in durability and wide availability. Ceramic enamel and organic enamel have approximately the same cost, and both are currently slightly lower in cost than black chrome, black copper, or black zinc. Black nickel is relatively unavailable and, because of that, realistic cost comparisons are not possible.

Suited for Space

NASA Technical Reports Server (NTRS)

Kosmo, Joseph J.

2006-01-01

This viewgraph presentation describes the basic functions of space suits for EVA astronauts. Space suits are also described from the past, present and future space missions. The contents include: 1) Why Do You Need A Space Suit?; 2) Generic EVA System Requirements; 3) Apollo Lunar Surface Cycling Certification; 4) EVA Operating Cycles for Mars Surface Missions; 5) Mars Surface EVA Mission Cycle Requirements; 6) Robustness Durability Requirements Comparison; 7) Carry-Weight Capabilities; 8) EVA System Challenges (Mars); 9) Human Planetary Surface Exploration Experience; 10) NASA Johnson Space Center Planetary Analog Activities; 11) Why Perform Remote Field Tests; and 12) Other Reasons Why We Perform Remote Field Tests.

Complexing agents and pH influence on chemical durability of type I moulded glass containers.

PubMed

Biavati, Alberto; Poncini, Michele; Ferrarini, Arianna; Favaro, Nicola; Scarpa, Martina; Vallotto, Marta

2017-06-16

Among the factors that affect the glass surface chemical durability, pH and complexing agents presence in aqueous solution have the main role (1). Glass surface attack can be also related to the delamination issue with glass particles appearance in the pharmaceutical preparation. A few methods to check for glass containers delamination propensity and some control guidelines have been proposed (2,3). The present study emphasizes the possible synergy between a few complexing agents with pH on the borosilicate glass chemical durability. Hydrolytic attack was performed in small volume 23 ml type I glass containers autoclaved according to EP or USP for 1 hour at 121°C, in order to enhance the chemical attack due to time, temperature and the unfavourable surface/volume ratio. 0,048 M or 0.024 M (moles/liter) solutions of the acids citric, glutaric, acetic, EDTA (ethylenediaminetetraacetic acid) and sodium phosphate with water for comparison, were used for the trials. The pH was adjusted ± 0,05 units at fixed values 5,5-6,6-7-7,4-8-9 by LiOH diluted solution. Since silicon is the main glass network former, silicon release into the attack solutions was chosen as the main index of the glass surface attack and analysed by ICPAES. The work was completed by the analysis of the silicon release in the worst attack conditions, of moulded glass, soda lime type II and tubing borosilicate glass vials to compare different glass compositions and forming technologies. Surface analysis by SEM was finally performed to check for the surface status after the worst chemical attack condition by citric acid. Copyright © 2017, Parenteral Drug Association.

75 FR 51245 - Agency Information Collection Activities; Proposed Collection; Comment Request; Durable Nursery...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-19

... perceptions regarding such products. The survey will gather information on the characteristics and usage... Activities; Proposed Collection; Comment Request; Durable Nursery Products Exposure Survey AGENCY: Consumer... draft survey regarding ownership and use characteristics of durable infant or toddler products. DATES...

A rule-based expert system applied to moisture durability of building envelopes

DOE PAGES

Boudreaux, Philip R.; Pallin, Simon B.; Accawi, Gina K.; ...

2018-01-09

The moisture durability of an envelope component such as a wall or roof is difficult to predict. Moisture durability depends on all the construction materials used, as well as the climate, orientation, air tightness, and indoor conditions. Modern building codes require more insulation and tighter construction but provide little guidance about how to ensure these energy-efficient assemblies remain moisture durable. Furthermore, as new products and materials are introduced, builders are increasingly uncertain about the long-term durability of their building envelope designs. Oak Ridge National Laboratory and the US Department of Energy’s Building America Program are applying a rule-based expert systemmore » methodology in a web tool to help designers determine whether a given wall design is likely to be moisture durable and provide expert guidance on moisture risk management specific to a wall design and climate. Finally, the expert system is populated with knowledge from both expert judgment and probabilistic hygrothermal simulation results.« less

Durable superhydrophobic paper enabled by surface sizing of starch-based composite films

NASA Astrophysics Data System (ADS)

Chen, Gang; Zhu, Penghui; Kuang, Yudi; Liu, Yu; Lin, Donghan; Peng, Congxing; Wen, Zhicheng; Fang, Zhiqiang

2017-07-01

Superhydrophobic paper with remarkable durability is of considerable interest for its practical applications. In this study, a scalable, inexpensive, and universal surface sizing technique was implemented to prepare superhydrophobic paper with enhanced durability. A thin layer of starch-based composite, acting as a bio-binder, was first coated onto the paper surface by a sophisticated manufacturing technique called surface sizing, immediately followed by a spray coating of hexamethyl disilazane treated silica nanoparticles (HMDS-SiNPs) dispersed in ethanol on the surface of the wet starch-coated sheet, and the dual layers dried at the same time. Consequently, durable superhydrophobic paper with bi-layer structure was obtained after air drying. The as-prepared superhydrophobic paper not only exhibited a self-cleaning behavior, but also presented an enhanced durability against scratching, bending/deformation, as well as moisture. The universal surface sizing of starch-based composites may pave the way for the up-scaled and cost-effective production of durable superhydrophobic paper.

A rule-based expert system applied to moisture durability of building envelopes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boudreaux, Philip R.; Pallin, Simon B.; Accawi, Gina K.

The moisture durability of an envelope component such as a wall or roof is difficult to predict. Moisture durability depends on all the construction materials used, as well as the climate, orientation, air tightness, and indoor conditions. Modern building codes require more insulation and tighter construction but provide little guidance about how to ensure these energy-efficient assemblies remain moisture durable. Furthermore, as new products and materials are introduced, builders are increasingly uncertain about the long-term durability of their building envelope designs. Oak Ridge National Laboratory and the US Department of Energy’s Building America Program are applying a rule-based expert systemmore » methodology in a web tool to help designers determine whether a given wall design is likely to be moisture durable and provide expert guidance on moisture risk management specific to a wall design and climate. Finally, the expert system is populated with knowledge from both expert judgment and probabilistic hygrothermal simulation results.« less

Durability of waste glass flax fiber reinforced mortar

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aly, M.; Hashmi, M. S. J.; Olabi, A. G.

2011-01-17

The main concern for natural fibre reinforced mortar composites is the durability of the fibres in the alkaline environment of cement. The composites may undergo a reduction in strength as a result of weakening of the fibres by a combination of alkali attack and fibre mineralisation. In order to enhance the durability of natural fiber reinforced cement composites several approaches have been studied including fiber impregnation, sealing of the matrix pore system and reduction of matrix alkalinity through the use of pozzolanic materials. In this study waste glass powder was used as a pozzolanic additive to improve the durability performancemore » of flax fiber reinforced mortar (FFRM). The durability of the FFRM was studied by determining the effects of ageing in water and exposure to wetting and drying cycles; on the microstructures and flexural behaviour of the composites. The mortar tests demonstrated that the waste glass powder has significant effect on improving the durability of FFRM.« less

Durability of renal artery stents in patients with transrenal abdominal aortic endografts.

PubMed

Baril, Donald T; Lookstein, Robert A; Jacobs, Tikva S; Won, Jamie; Marin, Michael L

2007-05-01

The management of renal artery stenosis in patients with abdominal aortic aneurysms continues to be complex and technically challenging despite advances in endovascular therapy. There is growing concern about the durability of renal artery stents in the setting of transrenal abdominal aortic endografts. This study reports a single-center experience of renal artery stenting with transrenal abdominal aortic endografts for patients with renal artery stenosis. All patients undergoing endovascular abdominal aortic aneurysm repair preceded or followed by renal artery stent placement between January 1999 and December 2005 were retrospectively reviewed from a prospectively gathered endovascular database. Patients were surveyed after renal stent procedures with multidetector computed tomography angiography or duplex sonography. The surveillance data were analyzed for primary patency of the renal artery stent at 6 months, incidence of complications, need for secondary interventions, and changes in creatinine clearance (CrCl). Sixty-two renal artery stents were placed in 56 patients (44 men, 12 women) with a mean age of 77.3 years (range, 61 to 94 years). Forty-one were placed before the endograft procedure, eight were placed during the endograft procedure, and 13 were placed postoperatively. There were no major or minor complications related to the renal artery stent procedures. Transrenal aortic endografts were used in 44 of the 56 patients, and 12 had devices with infrarenal fixation. The mean follow-up was 18.5 months (range, 1 to 73 months). The 6-month primary patency, which could be evaluated for 51 renal artery stents, was 97.4% (37/38) in patients with transrenal fixation and 84.6% (11/13) in patients with infrarenal fixation. The overall rate of in-stent restenosis was 8.5% (4/47) in the transrenal fixation group and 20.0% (3/15) in the infrarenal fixation group. The overall occlusion rate was 2.1% (1/47) in the transrenal fixation group and 0% (0/15) in infrarenal fixation group. Five (83.3%) of six patients underwent successful treatment of in-stent restenosis with placement of a new stent in all five cases. CrCl decreased in the total group by 4.2 +/- 11.8 mL/min, by 4.7 +/- 12.0 mL/min in patients with transrenal fixation, and by 2.2 +/- 11.0 mL/min in patients with infrarenal fixation. The presence of a transrenal aortic endograft did not affect the outcome of the renal artery revascularization procedure in this cohort. Renal artery stenting in the presence of transrenal abdominal aortic endografts appears to be a safe procedure without adverse effect on renal artery stent patency or renal function.

Comparison of 1997 Medicare relative value units for gender-specific procedures: is Adam still worth more than Eve?

PubMed

Goff, B A; Muntz, H G; Cain, J M

1997-08-01

On January 1, 1992, Congress implemented a Medicare payment system based on relative value units (RVUs). The total RVU (which is made up of work, practice, and malpractice RVUs) is multiplied by a dollar conversion factor to set the reimbursement for all procedures covered by Medicare. In a previous study, we found that significant gender bias exists in Medicare reimbursement for female-specific services. Recently, HCFA approved increases (beginning January 1997) in the work RVU for many gynecologic procedures. This study was undertaken to compare work and total RVUs for gender-specific procedures effective January 1, 1997. Using the May 1996 Federal Register, we compared work and total RVUs for 24 pairs of gender-specific procedures. The groups were matched so that the amount of work and level of difficulty would be similar, if not identical. We validated our selection of procedures for comparison by also evaluating the average time required to perform these procedures. Comparison of work RVUs for the 24 paired procedures revealed that in 19 cases (80%), male-specific procedures had a higher RVU; in 3 cases (12%), female-specific procedures were higher; and in 2 cases, there was no difference. On average, work RVUs were 49% higher for urologic procedures than for gynecologic procedures. Comparison of total RVUs revealed that in 20 cases (83%), urologic procedures had a higher total RVU and in 3 cases (12%), gynecologic procedures were higher. On average, male-specific surgeries are reimbursed at an amount which is 37% higher than that for female-specific surgeries. Recent increases in work RVUs for many gynecologic procedures have resulted in improved reimbursement. However, even with these improvements, significant gender bias still exists in the Medicare reimbursement of female-specific procedures. This gender bias is further magnified as more private insurance carriers use the system to set reimbursement.

40 CFR 86.1820-01 - Durability group determination.

Code of Federal Regulations, 2011 CFR

2011-07-01

... into durability groups based on the criteria listed above (such as non-catalyst control system... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Durability group determination. 86... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED...

40 CFR 86.1820-01 - Durability group determination.

Code of Federal Regulations, 2014 CFR

2014-07-01

... into durability groups based on the criteria listed above (such as non-catalyst control system... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Durability group determination. 86... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES General...

40 CFR 86.1820-01 - Durability group determination.

Code of Federal Regulations, 2010 CFR

2010-07-01

... into durability groups based on the criteria listed above (such as non-catalyst control system... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Durability group determination. 86... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED...

40 CFR 86.1820-01 - Durability group determination.

Code of Federal Regulations, 2013 CFR

2013-07-01

... into durability groups based on the criteria listed above (such as non-catalyst control system... 40 Protection of Environment 20 2013-07-01 2013-07-01 false Durability group determination. 86... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED...

40 CFR 86.1820-01 - Durability group determination.

Code of Federal Regulations, 2012 CFR

2012-07-01

... into durability groups based on the criteria listed above (such as non-catalyst control system... 40 Protection of Environment 20 2012-07-01 2012-07-01 false Durability group determination. 86... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED...

40 CFR 86.094-13 - Light-duty exhaust durability programs.

Code of Federal Regulations, 2011 CFR

2011-07-01

... and Heavy-Duty Engines, and for 1985 and Later Model Year New Gasoline Fueled, Natural Gas-Fueled... selection methods, durability data vehicle compliance requirements, in-use verification requirements... provisions of § 86.094-25. (3) Vehicle/component selection method. Durability data vehicles shall be selected...

40 CFR 94.219 - Durability data engine selection.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Durability data engine selection. 94... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE COMPRESSION-IGNITION ENGINES Certification Provisions § 94.219 Durability data engine selection. (a) For Category 1 and Category 2 engines, the manufacturer shall select...

Nitrogen and Fluorine-Codoped Carbon Nanowire Aerogels as Metal-Free Electrocatalysts for Oxygen Reduction Reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fu, Shaofang; Zhu, Chengzhou; Song, Junhua

2017-07-11

The development of active, durable, and low-cost catalysts to replace noble metal-based materials is highly desirable to promote the sluggish oxygen reduction reaction in fuel cells. Herein, nitrogen and fluorine-codoped three-dimensional carbon nanowire aerogels, composed of interconnected carbon nanowires, were synthesized for the first time by a hydrothermal carbonization process. Owing to their porous nanostructures and heteroatom-doping, the as-prepared carbon nanowire aerogels, with optimized composition, present excellent electrocatalytic activity that is comparable to commercial Pt/C. Remarkably, the aerogels also exhibit superior stability and methanol tolerance. This synthesis procedure paves a new way to design novel heteroatomdoped catalysts.

The US health care system: Part 1: Our current system.

PubMed

Nuwer, M R; Esper, G J; Donofrio, P D; Szaflarski, J P; Barkley, G L; Swift, T R

2008-12-02

The US health care crisis is of great concern to American neurologists. The United States has the world's most expensive health care system yet one-sixth of Americans are uninsured. The cost and volume of procedures is expanding, while reimbursement for office visits is declining. Pharmaceutical costs, durable goods, and home health care are growing disproportionately to other services. Carriers spend more for their own administration and profit than on payments to physicians. This first article on the US health care system identifies problems and proposes solutions, many of which are championed by the American Academy of Neurology through its legislative and regulatory committees.

Preformed posterior stainless steel crowns: an update.

PubMed

Croll, T P

1999-02-01

For almost 50 years, dentists have used stainless steel crowns for primary and permanent posterior teeth. No other type of restoration offers the convenience, low cost, durability, and reliability of such crowns when interim full-coronal coverage is required. Preformed stainless steel crowns have improved over the years. Better luting cements have been developed and different methods of crown manipulation have evolved. This article reviews stainless steel crown procedures for primary and permanent posterior teeth. Step-by-step placement of a primary molar stainless steel crown is documented and permanent molar stainless steel crown restoration is described. A method for repairing a worn-through crown also is reviewed.

42 CFR 402.1 - Basis and scope.

Code of Federal Regulations, 2013 CFR

2013-10-01

...)(A) and 1842(j)(2)—Any durable medical equipment supplier that knowingly and willfully charges for a... nonparticipating durable medical equipment supplier that knowingly and willfully, in violation of section 1834(a....) (9) Section 1834(j)(2)(A)(iii)—Any supplier of durable medical equipment, including a supplier of...

42 CFR 402.1 - Basis and scope.

Code of Federal Regulations, 2014 CFR

2014-10-01

...)(A) and 1842(j)(2)—Any durable medical equipment supplier that knowingly and willfully charges for a... nonparticipating durable medical equipment supplier that knowingly and willfully, in violation of section 1834(a....) (9) Section 1834(j)(2)(A)(iii)—Any supplier of durable medical equipment, including a supplier of...

77 FR 36292 - Notice Pursuant to the National Cooperative Research and Production Act of 1993-Cooperative...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-18

... Production Act of 1993--Cooperative Research Group on Particle Sensor Performance and Durability Notice is... Research Group on Particle Sensor Performance and Durability (``PSPD'') has filed written notifications... the performance and durability of various particle sensor technologies on a diesel engine platform...

Fifty-Year Durability Evaluation of Posts Treated with Industrial Wood Preservatives

Treesearch

Stan T. Lebow; Patricia Lebow; Bessie Woodward; Grant T. Kirker; Rachel Arango

2015-01-01

Long-term durability data are needed to improve service life estimates for treated wood products used as critical structural supports in industrial applications. This article reports the durability of longleaf pine (Pinus palustris) posts pressure treated with ammoniacal copper arsenate (ACA), chromated copper arsenate (CCA), creosote, or...

Effect of Unprofessional Supervision on Durability of Buildings.

PubMed

Yahaghi, Javad

2018-02-01

The durability of buildings which depends on the nature of the supervisory system used in their construction is an important feature of the construction industry. This article tries to draw the readers' attention to the effect of untrained and unprofessional building supervisors and their unethical performance on the durability of buildings.

Laboratory Evaluations of Durability of Southern Pine Pressure Treated With Extractives From Durable Wood Species

Treesearch

Grant T. Kirker; Amy Blodgett; Patricia Lebow

2015-01-01

Extracts from sawdust of four naturally durable wood species [Alaskan yellow cedar, AYC, Cupressus nootkanansis D. Don 1824; eastern red cedar, ERC, Juniperus virginiana L.; honey mesquite, HM, Prosopis glandulosa Torr.; and black locust, BL, Robinia pseudoacacia L.] were used to treat...

A zwitterionic macro-crosslinker for durable non-fouling coatings.

PubMed

Wang, Wei; Lu, Yang; Xie, Jinbing; Zhu, Hui; Cao, Zhiqiang

2016-03-28

A novel zwitterionic macro-crosslinker was developed and applied to fabricate durable non-fouling coatings on a polyurethane substrate. The zwitterionic macro-crosslinker coating exhibited superior durability over the traditional brush polymer coating and was able to retain its non-fouling property even after weeks of shearing in flowing liquid.

Experimental research on durability of recycled aggregate concrete under freeze- thaw cycles

NASA Astrophysics Data System (ADS)

Cheng, Yanqiu; Shang, Xiaoyu; Zhang, Youjia

2017-07-01

The freeze-thaw durability of recycled aggregate concrete has significance for the concrete buildings in the cold region. In this paper, the rapid freezing and thawing cycles experience on recycle aggregate concrete was conducted to study on the effects of recycle aggregate amount, water-binder ratio and fly ash on freeze-thaw durability of recycle aggregate concrete. The results indicates that recycle aggregate amount makes the significant influence on the freeze-thaw durability. With the increase of recycled aggregates amount, the freeze-thaw resistance for recycled aggregate concrete decreases. Recycled aggregate concrete with lower water cement ratio demonstrates better performance of freeze-thaw durability. It is advised that the amount of fly ash is less than 30% for admixture of recycled aggregates in the cold region.

Friction Durability of Extremely Thin Diamond-Like Carbon Films at High Temperature

PubMed Central

Miyake, Shojiro; Suzuki, Shota; Miyake, Masatoshi

2017-01-01

To clarify the friction durability, both during and after the high-temperature heating of nanometer-thick diamond-like carbon (DLC) films, deposited using filtered cathodic vacuum arc (FCVA) and plasma chemical vapor deposition (P-CVD) methods, the dependence of the friction coefficient on the load and sliding cycles of the DLC films, were evaluated. Cluster-I consisted of a low friction area in which the DLC film was effective, while cluster-II consisted of a high friction area in which the lubricating effect of the DLC film was lost. The friction durability of the films was evaluated by statistical cluster analysis. Extremely thin FCVA-DLC films exhibited an excellent wear resistance at room temperature, but their friction durability was decreased at high temperatures. In contrast, the durability of the P-CVD-DLC films was increased at high temperatures when compared with that observed at room temperature. This inverse dependence on temperature corresponded to the nano-friction results obtained by atomic force microscopy. The decrease in the friction durability of the FCVA-DLC films at high temperatures, was caused by a complex effect of temperature and friction. The tribochemical reaction produced by the P-CVD-DLC films reduced their friction coefficient, increasing their durability at high temperatures. PMID:28772520

Friction Durability of Extremely Thin Diamond-Like Carbon Films at High Temperature.

PubMed

Miyake, Shojiro; Suzuki, Shota; Miyake, Masatoshi

2017-02-10

To clarify the friction durability, both during and after the high-temperature heating of nanometer-thick diamond-like carbon (DLC) films, deposited using filtered cathodic vacuum arc (FCVA) and plasma chemical vapor deposition (P-CVD) methods, the dependence of the friction coefficient on the load and sliding cycles of the DLC films, were evaluated. Cluster-I consisted of a low friction area in which the DLC film was effective, while cluster-II consisted of a high friction area in which the lubricating effect of the DLC film was lost. The friction durability of the films was evaluated by statistical cluster analysis. Extremely thin FCVA-DLC films exhibited an excellent wear resistance at room temperature, but their friction durability was decreased at high temperatures. In contrast, the durability of the P-CVD-DLC films was increased at high temperatures when compared with that observed at room temperature. This inverse dependence on temperature corresponded to the nano-friction results obtained by atomic force microscopy. The decrease in the friction durability of the FCVA-DLC films at high temperatures, was caused by a complex effect of temperature and friction. The tribochemical reaction produced by the P-CVD-DLC films reduced their friction coefficient, increasing their durability at high temperatures.

A non-invasive navigation system for retargeting gastroscopic lesions.

PubMed

Liu, Jiquan; Wang, Bin; Hu, Weiling; Zong, Yun; Si, Jianmin; Duan, Huilong

2014-01-01

Biopsy is a traditional endoscopic surveillance of premalignant gastric lesions, and endoscopic tattooing is used for marking the biopsy's location. However, the tattooing has several disadvantages. For example, the procedure is an invasive operation and may not be durable due to the diffusion. Moreover, it is procedurally cumbersome with an associated risk of technical failure. In this study, a computer aided endoscopic navigation system (CAEN system) was developed for a non-invasive biopsy procedure. The CAEN system consists of a new, designed six degree of freedom (6-DOF) tracking endoscope device and a computer simulated work station. During the procedure, the endoscopist uses the tip of the tracking endoscope to touch the lesion. Then, the lesion's location is recorded in the work station, which then guides the endoscopist in retargeting the lesions in the follow-ups. The clinical experimental results demonstrate that the accuracy at the angularis is 5.2 ± 2.8 mm, at the antral lesser curvature is 7.2 ± 2.0 mm, at the antral greater curvature is 6.3 ± 3.1 mm, at the antral posterior wall is 8.2 ± 1.6 mm, and at the antral anterior wall is 7.9 ± 1.3 mm. The mean accuracy is 7.5 mm, and the P-value is 0.023, which is likely suitable for clinical practice. Furthermore, the proposed CAEN system requires less procedural time than the tattooing.

[Indications for and clinical outcome of the Ross procedure: a review].

PubMed

Morita, K; Kurosawa, H

2001-04-01

The Ross procedure has been used increasingly to treat aortic valve disease in children and young adults. The primary indication for the Ross procedure is to provide a permanent valve replacement in children with congenital aortic stenosis. More recently, it has been extended to young adults with a bicuspid aortic valve and small aortic annulus, especially women wishing to have children. Other possible indications include complex left ventricular outflow obstructive disease, native or prosthetic valve endocarditis, and adult aortic insufficiency with a dilated aortic annulus. Conversely, Marfan syndrome is considered to an absolute contraindication, and this procedure should be used with caution in patients with rheumatic valve disease and a dysplastic dilated aortic root because of the higher associated incidence of autograft dysfunction. The technique of total aortic root replacement has become the preferred method of autograft implantation, because it carries the lowest risk of pulmonary autograft failure. In patients with marked graft-host size mismatch, either concomitant aortic annulus reduction and fixation or aortic annulus enlargement (i.e., the Ross-Konno procedure) should be performed. The Ross Procedure International Registry data document that in the modern era (post-1986) the early and late mortality rate is 2.5% and 1%, respectively. Excellent long-term results have been reported, and the benefits of this procedure include optimal hemodynamics, low risk of endocarditis, resistance to infection in patients with active endocarditis, and nonthrombogeneicity and therefore few anticoagulation-related complications. The Ross procedure can be performed with acceptable early and mid-term mortality and excellent autograft durability. Further long-term follow-up will confirm the role of this procedure in patients with various types of aortic valve disease.

Long-term performance of the Hancock bioprosthetic valved conduit in the aortic root position.

PubMed

Badiu, Catalin C; Bleiziffer, Sabine; Eichinger, Walter B; Hettich, Ina; Krane, Markus; Bauernschmitt, Robert; Lange, Rüdiger

2011-03-01

The study aim was to assess long-term morbidity and mortality with special regard to prosthesis durability after aortic root replacement with the Hancock bioprosthetic porcine conduit. Between 1975 and 2004, a total of 81 patients (55 males, 26 females; mean age 58 +/- 18 years) underwent aortic root replacement with the Hancock conduit for aortic dissection (n = 22; 27%), ascending aortic aneurysm (n = 57; 70%), or porcelain aorta (n = 2; 3%). Twenty-five patients (31%) underwent an emergency operation, 12 (15%) presented with Marfan syndrome, and eight (10%) had undergone previous cardiac surgery. Concomitant procedures were performed in 26 cases (32%). The follow up was 98% complete; the mean follow up was 4.8 +/- 4.0 years (range: 1 day to 16.7 years), and the cumulative follow up was 403 patient-years. Actuarial event-free rates were calculated, and valve-related complications classified according to guidelines for reporting morbidity and mortality after cardiac valvular operations. There were seven (9%) operative deaths and four (5%) in-hospital deaths. Actuarial survival rates at five and 10 years (excluding operative deaths) were 77.0 +/- 5.3% and 54.0 +/- 7.5%, respectively. Actuarial freedom from aortic valve reoperation at five and 10 years was 98 +/- 1.6% and 64 +/- 10.2%, from structural valve deterioration 88.1 +/- 4.7% and 49.9 +/- 9.6%, from thromboembolic events 87.4 +/- 4.6% and 75.1 +/- 9.5%, and from major bleeding events 90.2 +/- 3.9% and 75.4 +/- 8.1%, respectively. Among redo procedures, the stentless Hancock valve could be excised without separating the synthetic graft from the left ventricular outflow tract, and a stented valve prosthesis thus implanted. Hence, it was possible to avoid a second Bentall operation. The long-term survival rates after aortic root replacement with the bioprosthetic Hancock conduit were reasonable for this demanding patient cohort. However, the durability of the prosthesis was inferior to that reported for the stented Hancock valve substitute. The key benefit of this bioprosthetic valved conduit was the simplified redo procedure.

Bladder augmentation without integration of intact bowel segments: critical review and future perspectives.

PubMed

Gurocak, Serhat; De Gier, Robert P E; Feitz, Wouter

2007-03-01

We evaluated the long-term results of autoaugmentation in the pediatric age group and summarized technical adaptations, experimental options and future perspectives for treating these patients. A directed MEDLINE literature review was performed to assess different techniques and alternative options in autoaugmentation procedures. Of 150 studies 49 in the subgroup with the longest duration of followup to show the long-term outcome of the autoaugmentation procedures were chosen for this review. Information gained from these data was reviewed and new perspectives were summarized. Enterocystoplasy is an effective mode of therapy with acceptable morbidity and satisfactory clinical results, although it is major intraperitoneal surgery with various complications and patients need prolonged convalescence to adapt to these surgical procedures. On the other hand, patient selection seems to be the most crucial step for the success of autoaugmentation procedures because the clinical outcome does not appear to be durable. Achievement of better compliance after autoaugmentation procedures seems to be less pronounced and of shorter duration than that of conventional enterocystoplasty. On the other hand, the low morbidity and lack of side effects of bowel integration into the urinary tract are the definite advantages of this technique. It is the responsibility of the physician to determine the balance between the limited efficacy of the procedures vs the definite advantages. Although functionally improved parameters are obtained in tissue engineered autologous bladders, there is an absolute need for additional studies before this challenging technique could be applied widely.

Beneficial Role of Copper in the Enhancement of Durability of Ordered Intermetallic PtFeCu Catalyst for Electrocatalytic Oxygen Reduction.

PubMed

Arumugam, Balamurugan; Tamaki, Takanori; Yamaguchi, Takeo

2015-08-05

Design of Pt alloy catalysts with enhanced activity and durability is a key challenge for polymer electrolyte membrane fuel cells. In the present work, we compare the durability of the ordered intermetallic face-centered tetragonal (fct) PtFeCu catalyst for the oxygen reduction reaction (ORR) relative to its counterpart bimetallic catalysts, i.e., the ordered intermetallic fct-PtFe catalyst and the commercial catalyst from Tanaka Kikinzoku Kogyo, TKK-PtC. Although both fct catalysts initially exhibited an ordered structure and mass activity approximately 2.5 times higher than that of TKK-Pt/C, the presence of Cu at the ordered intermetallic fct-PtFeCu catalyst led to a significant enhancement in durability compared to that of the ordered intermetallic fct-PtFe catalyst. The ordered intermetallic fct-PtFeCu catalyst retained more than 70% of its mass activity and electrochemically active surface area (ECSA) over 10 000 durability cycles carried out at 60 °C. In contrast, the ordered intermetallic fct-PtFe catalyst maintained only about 40% of its activity. The temperature of the durability experiment is also shown to be important: the catalyst was more severely degraded at 60 °C than at room temperature. To obtain insight into the observed enhancement in durability of fct-PtFeCu catalyst, a postmortem analysis of the ordered intermetallic fct-PtFeCu catalyst was carried out using scanning transmission electron microscopy-energy dispersive X-ray spectroscopy (STEM-EDX) line scan. The STEM-EDX line scans of the ordered intermetallic fct-PtFeCu catalyst over 10 000 durability cycles showed a smaller degree of Fe and Cu dissolution from the catalyst. Conversely, large dissolution of Fe was identified in the ordered intermetallic fct-PtFe catalyst, indicating a lesser retention of Fe that causes the destruction of ordered structure and gives rise to poor durability. The enhancement in the durability of the ordered intermetallic fct-PtFeCu catalyst is ascribed to the synergistic effects of Cu presence and the ordered structure of catalyst.

A Tablet-Based Multimedia Education Tool Improves Provider and Subject Knowledge of Inhaler Use Techniques.

PubMed

Mulhall, Aaron M; Zafar, Muhammad A; Record, Samantha; Channell, Herman; Panos, Ralph J

2017-02-01

Although inhaled medications are effective therapies for COPD, many patients and providers use them incorrectly. We recruited providers who prescribe inhalers or teach inhaler technique and assessed their use of metered-dose inhalers (MDIs), various dry powder inhalers (DPIs), and Respimat using predefined checklists. Then they watched tablet-based multimedia educational videos that demonstrated correct inhaler technique by a clinical pharmacist with teach-back from a patient and were re-evaluated. We also recruited patients with COPD and assessed their use of their prescribed inhalers and then retested them after 3-6 months. Baseline and follow-up respiratory symptoms were measured by the COPD Assessment Test. Fifty-eight providers and 50 subjects participated. For all providers, correct inhaler technique (reported as percentage correct steps) increased after the videos: MDI without a spacer (72% vs 97%) MDI with a spacer (72% vs 96%), formoterol DPI (50% vs 94%), mometasone DPI (43% vs 95%), tiotropium DPI (73% vs 99%), and Respimat (32% vs 93%) (before vs after, P < .001 for all comparisons). Subjects also improved their inhaler use technique after viewing the educational videos: MDI without a spacer (69% vs 92%), MDI with a spacer (73% vs 95%), and tiotropium DPI (83% vs 96%) (before vs after, P < .001 for all comparisons). The beneficial effect of this educational intervention declined slightly for subjects but was durably improved after several months. COPD Assessment Test scores did not demonstrate any change in respiratory symptoms. A tablet-based inhaler education tool improved inhaler technique for both providers and subjects. Although this intervention did show durable efficacy for improving inhaler use by patients, it did not reduce their respiratory symptoms. Copyright © 2017 by Daedalus Enterprises.

Experimentally Observed Electrical Durability of 4H-SiC JFET ICs Operating from 500 C to 700 C

NASA Technical Reports Server (NTRS)

Neudeck, Philip G.; Spry, David J.; Chen, Liangyu; Lukco, Dorothy; Chang, Carl W.; Beheim, Glenn M.

2016-01-01

This ECSCRM 2016 submission presents further electrical testing and microscopic post-failure studies aimed at more comprehensive understanding of the durability limits of this extreme temperature IC technology. The results summarized represent an unprecedented combination of T 500 C semiconductor IC durability and functionality.

Coating WPC's using co-extrusion to improve durability

Treesearch

Nicole M. Stark; Laurent M. Matuana

2007-01-01

Wood-plastic composites (WPCs) have been gaining market share in the residential construction industry as lumber for decking, roof tiles, and siding. The durability of these materials in exterior environments is just beginning to be understood. Current research suggests that controlling moisture absorption by the composite is key to improving durability. Methods to...

Outdoor durability of wood-polymer composites

Treesearch

N. M. Stark; D. J. Gardner

2008-01-01

Wood-plastic composite (WPC) lumber is promoted as a low-maintenance, high-durability product (Clemons, 2002). However, after a decade of exterior use in the construction industry, questions have arisen regarding durability. These questions are based on documented evidence of failures in the field of WPC decking products due to such impacts as polymer degradation (...

Adhesives for Achieving Durable Bonds with Acetylated Wood

Treesearch

Charles Frihart; Rishawn Brandon; James Beecher; Rebecca Ibach

2017-01-01

Acetylation of wood imparts moisture durability, decay resistance, and dimensional stability to wood; however, making durable adhesive bonds with acetylated wood can be more difficult than with unmodified wood. The usual explanation is that the acetylated surface has fewer hydroxyl groups, resulting in a harder-to-wet surface and in fewer hydrogen bonds between wood...

Toward understanding molecular mechanisms of durable and non-durable resistance to stripe rust in wheat

USDA-ARS?s Scientific Manuscript database

Stripe rust of wheat, caused by Puccinia striiformis f. sp. tritici, continues causing severe damage worldwide. Durable resistance is a key for sustainable control of the disease. High-temperature adult-plant (HTAP) resistance, which expresses when weather becomes warm and plants grow old, has bee...

75 FR 2105 - Publication of OIG Updated Special Fraud Alert on Telemarketing by Durable Medical Equipment...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-14

... Inspector General Publication of OIG Updated Special Fraud Alert on Telemarketing by Durable Medical... Register notice sets forth the recently issued OIG Updated Special Fraud Alert addressing telemarketing by durable medical equipment (DME) suppliers. For the most part, OIG Special Fraud Alerts address national...

40 CFR 86.094-26 - Mileage and service accumulation; emission requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Gas-Fueled, Liquefied Petroleum Gas-Fueled and Methanol-Fueled Heavy-Duty Vehicles § 86.094-26 Mileage... the durability data obtained up to that point out to the durability useful life or to replace the... vehicles and durability data vehicles obtained pursuant to the provisions of this section will be used in...

40 CFR 86.094-26 - Mileage and service accumulation; emission requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Gas-Fueled, Liquefied Petroleum Gas-Fueled and Methanol-Fueled Heavy-Duty Vehicles § 86.094-26 Mileage... the durability data obtained up to that point out to the durability useful life or to replace the... vehicles and durability data vehicles obtained pursuant to the provisions of this section will be used in...

Durable soy-based adhesive dispersions

Treesearch

James M. Wescott; Amy Traska; Charles R. Frihart; Linda Lorenz

2005-01-01

An important aspect of any adhesive bond is that the bond maintains its integrity during its end use. Epoxies form highly durable bonds with many substrates but are usually not considered capable of forming completely durable bonds with wood by standard accelerated tests. However, epoxies are sold for wood boat construction, and some data have indicated that epoxies...

Four-year durability of clinical and haemodynamic outcomes of transcatheter aortic valve implantation with the self-expanding CoreValve.

PubMed

Gulino, Simona; Barbanti, Marco; Deste, Wanda; Immè, Sebastiano; Aruta, Patrizia; Bottari, Vera; Benvenuto, Emanuele; Tamburino, Claudia; Di Landro, Alessio; Liberto, Daria; Santonoceto, Letizia; Sicuso, Rita; Di Stefano, Daniele; Todaro, Denise; Di Simone, Emanuela; Indelicato, Antonino; Giannazzo, Daniela; Sgroi, Carmelo; Tamburino, Corrado

2016-10-10

Long-term data on the durability of currently available transcatheter heart valves are limited. We sought to assess four-year clinical and echocardiographic outcomes in patients undergoing transcatheter aortic valve implantation (TAVI) with the CoreValve prosthesis. Between June 2007 and February 2014, 450 consecutive patients with symptomatic severe aortic stenosis underwent TAVI in our institution. For the purposes of this study, we included only those patients undergoing successful TAVI with the CoreValve prosthesis who had a minimum follow-up of four years (n=125). Survival rates at one, two, three and four years were 83.2, 76.8, 73.6 and 66.3%, respectively. Aortic regurgitation was a common finding after the procedure, especially due to paravalvular regurgitation (PVR), which was observed in the majority of patients (71.5%), mostly mild (52.0%). Progression from mild acute PVR to moderate PVR at four-year follow-up was reported in three patients. No cases of severe PVR were observed. Prosthetic valve failure was reported in four patients (3.2%). Our study demonstrates that favourable outcomes after successful TAVI are associated with sustained clinical and functional cardiovascular benefits up to four-year follow-up. Signs of moderate prosthetic valve failure are present only in a small percentage of patients.

Fouling and long-term durability of an integrated forward osmosis and membrane distillation system.

PubMed

Husnain, T; Mi, B; Riffat, R

2015-01-01

An integrated forward osmosis (FO) and membrane distillation (MD) system has great potential for sustainable wastewater reuse. However, the fouling and long-term durability of the system remains largely unknown. This study investigates the fouling behaviour and efficiency of cleaning procedures of FO and MD membranes used for treating domestic wastewater. Results showed that a significant decline in flux of both FO and MD membranes were observed during treatment of wastewater with organic foulants. However, shear force generated by the increased cross-flow physically removed the loosely attached foulants from the FO membrane surface and resulted in 86-88% recovery of flux by cleaning with tap water. For the MD membrane, almost no flux recovery was achieved due to adsorption of organic foulants on the hydrophobic membrane surface, thus indicating significant irreversible fouling/wetting, which may not be effectively cleaned even with chemical reagents. Long-term (10 d) tests showed consistent performance of the FO membrane by rejecting the contaminants. However, organic foulants reduced the hydrophobicity of the MD membrane, caused wetting problems and allowed contaminants to pass through. The results demonstrate that combination of the FO and MD processes can effectively reduce irreversible membrane fouling and solve the wetting problem of the MD membrane.

Evaluation of morphology and size of cracks of the Interfacial Transition Zone (ITZ) in concrete containing fly ash (FA).

PubMed

Golewski, Grzegorz Ludwik

2018-06-07

Interfacial Transition Zone (ITZ) of coarse aggregate cement matrix is commonly regarded as the weakest element of concrete. In this phase - the first cracks in the material are initiated, and the process of destruction of the composite begins. An improvement of the ITZ properties are positively influenced by the mineral additives used for the composite. One of such a substitute for a binder is, potentially hazardous industrial waste, siliceous fly ash (FA). In this paper the ITZ between aggregate and cement paste in concretes containing FA is considered. The paper presents the results of tests on the effect of the addition of FA in the amount of: 0, 20 and 30% by weight of cement on morphology and size of cracks of the ITZ in composites. In matured concretes the smallest cracks occur in composite with the 20% FA additive. It can be concluded that composites with 20% addition of FA are characterized by low permeability and therefore high durability. The results of tests carried out can be helpful in obtaining concrete with the highest possible: strength, durability and reliability of operation. Moreover, such procedures also cause a restriction storage of hazardous materials, i.e. FA - by 160 million tons per year. Copyright © 2018 Elsevier B.V. All rights reserved.

Application of ground-penetrating radar technique to evaluate the waterfront location in hardened concrete

NASA Astrophysics Data System (ADS)

Rodríguez-Abad, Isabel; Klysz, Gilles; Martínez-Sala, Rosa; Balayssac, Jean Paul; Mené-Aparicio, Jesús

2016-12-01

The long-term performance of concrete structures is directly tied to two factors: concrete durability and strength. When assessing the durability of concrete structures, the study of the water penetration is paramount, because almost all reactions like corrosion, alkali-silica, sulfate, etc., which produce their deterioration, require the presence of water. Ground-penetrating radar (GPR) has shown to be very sensitive to water variations. On this basis, the objective of this experimental study is, firstly, to analyze the correlation between the water penetration depth in concrete samples and the GPR wave parameters. To do this, the samples were immersed into water for different time intervals and the wave parameters were obtained from signals registered when the antenna was placed on the immersed surface of the samples. Secondly, a procedure has been developed to be able to determine, from those signals, the reliability in the detection and location of waterfront depths. The results have revealed that GPR may have an enormous potential in this field, because excellent agreements were found between the correlated variables. In addition, when comparing the waterfront depths calculated from GPR measurements and those visually registered after breaking the samples, we observed that they totally agreed when the waterfront was more than 4 cm depth.

Low Earth Orbital Atomic Oxygen Interactions With Materials

NASA Technical Reports Server (NTRS)

Banks, Bruce A.; Miller, Sharon K.; deGroh, Kim K.

2004-01-01

Atomic oxygen is formed in the low Earth orbital environment (LEO) by photo dissociation of diatomic oxygen by short wavelength (< 243 nm) solar radiation which has sufficient energy to break the 5.12 eV O2 diatomic bond in an environment where the mean free path is sufficiently long ( 108 meters) that the probability of reassociation or the formation of ozone (O3) is small. As a consequence, between the altitudes of 180 and 650 km, atomic oxygen is the most abundant species. Spacecraft impact the atomic oxygen resident in LEO with sufficient energy to break hydrocarbon polymer bonds, causing oxidation and thinning of the polymers due to loss of volatile oxidation products. Mitigation techniques, such as the development of materials with improved durability to atomic oxygen attack, as well as atomic oxygen protective coatings, have been employed with varying degrees of success to improve durability of polymers in the LEO environment. Atomic oxygen can also oxidize silicones and silicone contamination to produce non-volatile silica deposits. Such contaminants are present on most LEO missions and can be a threat to performance of optical surfaces. The LEO atomic oxygen environment, its interactions with materials, results of space testing, computational modeling, mitigation techniques, and ground laboratory simulation procedures and issues are presented.

Proceedings of the Conference on the Design of Experiments in Army Research Development and Testing (26th) Held at New Mexico State University, Las Cruces, New Mexico on 22-24 October 1980.

DTIC Science & Technology

1981-06-01

normality and several types of nonnormality. Overall the rank transformation procedure seems to be the best. The Fisher’s LSD multiple comparisons procedure...the rank transformation procedure appears to maintain power better than Fisher’s LSD or the randomization proce- dures. The conclusion of this study...best. The Fisher’s LSD multiple comparisons procedure in the one way and two way layouts iv compared with a randomization procedure and with the same

Thermodynamic model of natural, medieval and nuclear waste glass durability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jantzen, C.M.; Plodinec, M.J.

1983-01-01

A thermodynamic model of glass durability based on hydration of structural units has been applied to natural glass, medieval window glasses, and glasses containing nuclear waste. The relative durability predicted from the calculated thermodynamics correlates directly with the experimentally observed release of structural silicon in the leaching solution in short-term laboratory tests. By choosing natural glasses and ancient glasses whose long-term performance is known, and which bracket the durability of waste glasses, the long-term stability of nuclear waste glasses can be interpolated among these materials. The current Savannah River defense waste glass formulation is as durable as natural basalt frommore » the Hanford Reservation (10/sup 6/ years old). The thermodynamic hydration energy is shown to be related to the bond energetics of the glass. 69 references, 2 figures, 1 table.« less

Durable crystalline Si photovoltaic modules based on silicone-sheet encapsulants

NASA Astrophysics Data System (ADS)

Hara, Kohjiro; Ohwada, Hiroto; Furihata, Tomoyoshi; Masuda, Atsushi

2018-02-01

Crystalline Si photovoltaic (PV) modules were fabricated with sheets of poly(dimethylsiloxane) (silicone) as an encapsulant. The long-term durability of the silicone-encapsulated PV modules was experimentally investigated. The silicone-based modules enhanced the long-term durability against potential-induced degradation (PID) and a damp-heat (DH) condition at 85 °C with 85% relative humidity (RH). In addition, we designed and fabricated substrate-type Si PV modules based on the silicone encapsulant and an Al-alloy plate as the substratum, which demonstrated high impact resistance and high incombustible performance. The high chemical stability, high volume resistivity, rubber-like elasticity, and incombustibility of the silicone encapsulant resulted in the high durability of the modules. Our results indicate that silicone is an attractive encapsulation material, as it improves the long-term durability of crystalline Si PV modules.

Materials research for high-speed civil transport and generic hypersonics: Composites durability

NASA Technical Reports Server (NTRS)

Allen-Lilly, Heather; Cregger, Eric; Hoffman, Daniel; Mccool, Jim

1995-01-01

This report covers a portion of an ongoing investigation of the durability of composites for the High Speed Civil Transport (HSCT) program. Candidate HSCT composites need to possess the high-temperature capability required for supersonic flight. This program was designed to initiate the design, analysis, fabrication, and testing of equipment intended for use in validating the long-term durability of materials for the HSCT. This equipment includes thermally actuated compression and tension fixtures, hydraulic-actuated reversible load fixtures, and thermal chambers. This equipment can be used for the durability evaluation of both composite and adhesive materials. Thermally actuated fixtures are recommended for fatigue cycling when long-term thermomechanical fatigue (TMF) data are required on coupon-sized tension or compression specimens. Long term durability testing plans for polymer matrix composite specimens are included.

A SAS(®) macro implementation of a multiple comparison post hoc test for a Kruskal-Wallis analysis.

PubMed

Elliott, Alan C; Hynan, Linda S

2011-04-01

The Kruskal-Wallis (KW) nonparametric analysis of variance is often used instead of a standard one-way ANOVA when data are from a suspected non-normal population. The KW omnibus procedure tests for some differences between groups, but provides no specific post hoc pair wise comparisons. This paper provides a SAS(®) macro implementation of a multiple comparison test based on significant Kruskal-Wallis results from the SAS NPAR1WAY procedure. The implementation is designed for up to 20 groups at a user-specified alpha significance level. A Monte-Carlo simulation compared this nonparametric procedure to commonly used parametric multiple comparison tests. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Applications of remote sensing, volume 3

NASA Technical Reports Server (NTRS)

Landgrebe, D. A. (Principal Investigator)

1977-01-01

The author has identified the following significant results. Of the four change detection techniques (post classification comparison, delta data, spectral/temporal, and layered spectral temporal), the post classification comparison was selected for further development. This was based upon test performances of the four change detection method, straightforwardness of the procedures, and the output products desired. A standardized modified, supervised classification procedure for analyzing the Texas coastal zone data was compiled. This procedure was developed in order that all quadrangles in the study are would be classified using similar analysis techniques to allow for meaningful comparisons and evaluations of the classifications.

Development of highly active and stable hybrid cathode catalyst for PEMFCs

NASA Astrophysics Data System (ADS)

Jung, Won Suk

Polymer electrolyte membrane fuel cells (PEMFCs) are attractive power sources of the future for a variety of applications including portable electronics, stationary power, and automobile application. However, sluggish cathode kinetics, high Pt cost, and durability issues inhibit the commercialization of PEMFCs. To overcome these drawbacks, research has been focused on alloying Pt with transition metals since alloy catalysts show significantly improved catalytic properties like high activity, selectivity, and durability. However, Pt-alloy catalysts synthesized using the conventional impregnation method exhibit uneven particle size and poor particle distribution resulting in poor performance and/or durability in PEMFCs. In this dissertation, a novel catalyst synthesis methodology is developed and compared with catalysts prepared using impregnation method and commercial catalysts. Two approaches are investigated for the catalyst development. The catalyst durability was studied under U. S. DRIVE Fuel Cell Tech Team suggested protocols. In the first approach, the carbon composite catalyst (CCC) having active sites for oxygen reduction reaction (ORR) is employed as a support for the synthesis of Pt/CCC catalyst. The structural and electrochemical properties of Pt/CCC catalyst are investigated using high-resolution transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy, while RDE and fuel cell testing are carried out to study the electrochemical properties. The synergistic effect of CCC and Pt is confirmed by the observed high activity towards ORR for the Pt/CCC catalyst. The second approach is the synthesis of Co-doped hybrid cathode catalysts (Co-doped Pt/CCC) by diffusing the Co metal present within the CCC support into the Pt nanoparticles during heat-treatment. The optimized Co-doped Pt/CCC catalyst performed better than the commercial catalysts and the catalyst prepared using the impregnation method in PEMFCs and showed high stability under 30,000 potential cycles between 0.6 and 1.0 V. To further increase the stability of the catalyst at high potential cycles (1.0-1.5 V), high temperature treatment is used to obtain graphitized carbon having optimum BET surface area. The novel catalyst synthesis procedure developed in this study was successfully applied for the synthesis of Co-doped Pt catalysts supported on the graphitized carbon which showed high activity and enhanced stability at high potentials.

GC-MS Characterizations of Termiticidal Heartwood Extractives from Wood Species Utilized in Pakistan

Treesearch

Mark Mankowski; Blossie Boyd; Barbar Hassan; Grant T. Kirker

2016-01-01

Wood species that exhibit innate tolerance to wood destroying organisms such as termites are considered to be naturally durable. This durability can, in part, be due to the complex chemical compounds in the heartwood of naturally durable wood species. We examined the effects of varying concentrations of heartwood extractives on the subterranean termite, ...

The need for performance criteria in evaluating the durability of wood products

Treesearch

Stan Lebow; Bessie Woodward; Patricia Lebow; Carol Clausen

2010-01-01

Data generated from wood-product durability evaluations can be difficult to interpret. Standard methods used to evaluate the potential long-term durability of wood products often provide little guidance on interpretation of test results. Decisions on acceptable performance for standardization and code compliance are based on the judgment of reviewers or committees....

Durability of sealants exposed to outdoor weathering and hot compression cycles

Treesearch

Gregory T. Schueneman; Steven Lacher; Christopher G. Hunt; Christopher C. White; Donald L. Hunston

2011-01-01

Sealants play an important role in weatherproofing structures by filling gaps and preventing air and water intrusion. When incorrectly selected or improperly applied, they may fail quickly, compromising durability of the structure. To ensure reliability and prevent the need for costly repairs to structures, it is necessary to measure durability and predict life...

Adhesive bonding and performance testing of bonded wood products

Treesearch

Charles R. Frihart

2005-01-01

Despite the importance of durable wood bonds, the factors that lead to durability are not well understood, and the internal forces exerted upon the bondline are often overlooked. Durability requires that the bonded assembly resist dimensional changes of wood with fluctuation of wood moisture levels. Both bonding and bond breaking steps need to be understood at cellular...

76 FR 20822 - Proposed Information Collection (Living Will and Durable Power of Attorney for Health Care...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-13

... Will and Durable Power of Attorney for Health Care) Activity: Comment Request AGENCY: Veterans Health... instructions about health care decisions in the event he or she is no longer has decision-making capability... information technology. Title: VA Advance Directive: Living Will and Durable Power of Attorney for Health Care...

Depth enhancement of ion sensitized data

DOEpatents

Lamartine, Bruce C.

2001-01-01

A process of fabricating a durable data storage medium is disclosed, the durable data storage medium capable of storing, digital or alphanumeric characters as well as graphical shapes or characters. Additionally, a durable data storage medium including a substrate having etched characters therein is disclosed, the substrate characterized as containing detectable residual amounts of ions used in the preparation process.

Are epoxy-wood bonds durable enough?

Treesearch

Charles R. Frihart

2005-01-01

An important aspect of any adhesive bond is that the bond maintains its integrity during its end use. Epoxies form highly durable bonds with many substrates but are usually not considered capable of forming completely durable bonds with wood by standard accelerated tests. However, epoxies are sold for wood boat construction, and some data have indicated that epoxies...

Wood-plastic composites with reduced moisture : effects of chemical modification on durability in the laboratory and field

Treesearch

Rebecca E. Ibach; Craig M. Clemons; Rebecca L. Schumann

2007-01-01

Although laboratory evaluations of wood-plastic composites (WPCs) are helpful in predicting long-term durability, field studies are needed to verify overall long-term durability. Field exposure can encompass numerous degradations i.e., fungal, ultraviolet light, moisture, wind, temperature, freeze/thaw, wet/ dry cycling, termites, mold, etc. that traditionally are...

Physician Reimbursement in Medicare Advantage Compared With Traditional Medicare and Commercial Health Insurance.

PubMed

Trish, Erin; Ginsburg, Paul; Gascue, Laura; Joyce, Geoffrey

2017-09-01

Nearly one-third of Medicare beneficiaries are enrolled in a Medicare Advantage (MA) plan, yet little is known about the prices that MA plans pay for physician services. Medicare Advantage insurers typically also sell commercial plans, and the extent to which MA physician reimbursement reflects traditional Medicare (TM) rates vs negotiated commercial prices is unclear. To compare prices paid for physician and other health care services in MA, traditional Medicare, and commercial plans. Retrospective analysis of claims data evaluating MA prices paid to physicians and for laboratory services and durable medical equipment between 2007 and 2012 in 348 US core-based statistical areas. The study population included all MA and commercial enrollees with a large national health insurer operating in both markets, as well as a 20% sample of TM beneficiaries. Enrollment in an MA plan. Mean reimbursement paid to physicians, laboratories, and durable medical equipment suppliers for MA and commercial enrollees relative to TM rates for 11 Healthcare Common Procedure Coding Systems (HCPCS) codes spanning 7 sites of care. The sample consisted of 144 million claims. Physician reimbursement in MA was more strongly tied to TM rates than commercial prices, although MA plans tended to pay physicians less than TM. For a mid-level office visit with an established patient (Current Procedural Terminology [CPT] code 99213), the mean MA price was 96.9% (95% CI, 96.7%-97.2%) of TM. Across the common physician services we evaluated, mean MA reimbursement ranged from 91.3% of TM for cataract removal in an ambulatory surgery center (CPT 66984; 95% CI, 90.7%-91.9%) to 102.3% of TM for complex evaluation and management of a patient in the emergency department (CPT 99285; 95% CI, 102.1%-102.6%). However, for laboratory services and durable medical equipment, where commercial prices are lower than TM rates, MA plans take advantage of these lower commercial prices, ranging from 67.4% for a walker (HCPCS code E0143; 95% CI, 66.3%-68.5%) to 75.8% for a complete blood cell count (CPT 85025; 95% CI, 75.0%-76.6%). Traditional Medicare's administratively set rates act as a strong anchor for physician reimbursement in the MA market, although MA plans succeed in negotiating lower prices for other health care services for which TM overpays. Reforms that transition the Medicare program toward some premium support models could substantially affect how physicians and other clinicians are paid.

Recent Advances in Durability and Damage Tolerance Methodology at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Ransom, J. B.; Glaessgen, E. H.; Raju, I. S.; Harris, C. E.

2007-01-01

Durability and damage tolerance (D&DT) issues are critical to the development of lighter, safer and more efficient aerospace vehicles. Durability is largely an economic life-cycle design consideration whereas damage tolerance directly addresses the structural airworthiness (safety) of the vehicle. Both D&DT methodologies must address the deleterious effects of changes in material properties and the initiation and growth of damage that may occur during the vehicle s service lifetime. The result of unanticipated D&DT response is often manifested in the form of catastrophic and potentially fatal accidents. As such, durability and damage tolerance requirements must be rigorously addressed for commercial transport aircraft and NASA spacecraft systems. This paper presents an overview of the recent and planned future research in durability and damage tolerance analytical and experimental methods for both metallic and composite aerospace structures at NASA Langley Research Center (LaRC).

Advanced Durability and Damage Tolerance Design and Analysis Methods for Composite Structures: Lessons Learned from NASA Technology Development Programs

NASA Technical Reports Server (NTRS)

Harris, Charles E.; Starnes, James H., Jr.; Shuart, Mark J.

2003-01-01

Aerospace vehicles are designed to be durable and damage tolerant. Durability is largely an economic life-cycle design consideration whereas damage tolerance directly addresses the structural airworthiness (safety) of the vehicle. However, both durability and damage tolerance design methodologies must address the deleterious effects of changes in material properties and the initiation and growth of microstructural damage that may occur during the service lifetime of the vehicle. Durability and damage tolerance design and certification requirements are addressed for commercial transport aircraft and NASA manned spacecraft systems. The state-of-the-art in advanced design and analysis methods is illustrated by discussing the results of several recently completed NASA technology development programs. These programs include the NASA Advanced Subsonic Technology Program demonstrating technologies for large transport aircraft and the X-33 hypersonic test vehicle demonstrating technologies for a single-stage-to-orbit space launch vehicle.

Durability of styrene-butadiene latex modified concrete

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shaker, F.A.; El-Dieb, A.S.; Reda, M.M.

1997-05-01

The durability of reinforced concrete structures represents a major concern to many investigators. The use of latex modified concrete (LMC) in construction has urged researchers to review and investigate its different properties. This study is part of a comprehensive investigation carried on the use of polymers in concrete. The main objective of this study to investigate and evaluate the main durability aspects of Styrene-Butadiene latex modified concrete (LMC) compared to those of conventional concrete. Also, the main microstructural characteristics of LMC were studied using a Scanning Electron Microscope (SEM). The SEM investigation of the LMC showed major differences in itsmore » microstructure compared to that of the conventional concrete. The LMC proved to be superior in its durability compared to the durability of conventional concrete especially its water tightness (measured by water penetration, absorption, and sorptivity tests), abrasion, corrosion, and sulphate resistance.« less

Durability of filament-wound composite flywheel rotors

NASA Astrophysics Data System (ADS)

Koyanagi, Jun

2012-02-01

This paper predicts the durability of two types of flywheels, one assumes to fail in the radial direction and the other assumes to fail in the circumferential direction. The flywheel failing in the radial direction is a conventional filament-wound composite flywheel and the one failing in the circumferential direction is a tailor-made type. The durability of the former is predicted by Micromechanics of Failure (MMF) (Ha et al. in J. Compos. Mater. 42:1873-1875, 2008), employing time-dependent matrix strength, and that of the latter is predicted by Simultaneous Fiber Failure (SFF) (Koyanagi et al. in J. Compos. Mater. 43:1901-1914, 2009), employing identical time-dependent matrix strength. The predicted durability of the latter is much greater than that of the former, depending on the interface strength. This study suggests that a relatively weak interface is necessary for high-durability composite flywheel fabrication.

Mode-Stirred Method Implementation for HIRF Susceptibility Testing and Results Comparison with Anechoic Method

NASA Technical Reports Server (NTRS)

Nguyen, Truong X.; Ely, Jay J.; Koppen, Sandra V.

2001-01-01

This paper describes the implementation of mode-stirred method for susceptibility testing according to the current DO-160D standard. Test results on an Engine Data Processor using the implemented procedure and the comparisons with the standard anechoic test results are presented. The comparison experimentally shows that the susceptibility thresholds found in mode-stirred method are consistently higher than anechoic. This is consistent with the recent statistical analysis finding by NIST that the current calibration procedure overstates field strength by a fixed amount. Once the test results are adjusted for this value, the comparisons with the anechoic results are excellent. The results also show that test method has excellent chamber to chamber repeatability. Several areas for improvements to the current procedure are also identified and implemented.

Historical maintenance relevant information road-map for a self-learning maintenance prediction procedural approach

NASA Astrophysics Data System (ADS)

Morales, Francisco J.; Reyes, Antonio; Cáceres, Noelia; Romero, Luis M.; Benitez, Francisco G.; Morgado, Joao; Duarte, Emanuel; Martins, Teresa

2017-09-01

A large percentage of transport infrastructures are composed of linear assets, such as roads and rail tracks. The large social and economic relevance of these constructions force the stakeholders to ensure a prolonged health/durability. Even though, inevitable malfunctioning, breaking down, and out-of-service periods arise randomly during the life cycle of the infrastructure. Predictive maintenance techniques tend to diminish the appearance of unpredicted failures and the execution of needed corrective interventions, envisaging the adequate interventions to be conducted before failures show up. This communication presents: i) A procedural approach, to be conducted, in order to collect the relevant information regarding the evolving state condition of the assets involved in all maintenance interventions; this reported and stored information constitutes a rich historical data base to train Machine Learning algorithms in order to generate reliable predictions of the interventions to be carried out in further time scenarios. ii) A schematic flow chart of the automatic learning procedure. iii) Self-learning rules from automatic learning from false positive/negatives. The description, testing, automatic learning approach and the outcomes of a pilot case are presented; finally some conclusions are outlined regarding the methodology proposed for improving the self-learning predictive capability.

Renal Angiomyolipoma: Mid- to Long-Term Results Following Embolization with Onyx.

PubMed

Thulasidasan, Narayanan; Sriskandakumar, Srividhiya; Ilyas, Shahzad; Sabharwal, Tarun

2016-12-01

Percutaneous transcatheter embolization is currently the preferred treatment for ruptured or enlarging renal angiomyolipoma (AML), although the optimum choice of embolic material has not yet been established. We present mid- to long-term outcomes following embolization of AMLs with Onyx. Ten AMLs in seven patients (including two with tuberous sclerosis) were embolized with Onyx. Patients were followed-up clinically, with tumour size and renal function measured pre- and post-procedure. Mean pre-treatment AML size was 63.4 mm (range 42-100). Mean clinical follow-up was 431.4 days (range 153-986) and imaging follow-up 284.2 days (range 30-741). There was no haemorrhage from treated lesions within the follow-up period. Of patients who had cross-sectional imaging pre- and post-procedure, mean decrease in AML size of 22 mm was seen after Onyx embolization (p = 0.0058, 95 % CI 9.13-34.87). No significant difference between serum creatinine was seen pre- and post-procedure (p = 0.54, 95 % CI 8.63-4.85). Onyx embolization of renal AMLs is effective in the medium to long term, with theoretical benefits in safety and durability of result.

Follow-up of renal and mesenteric artery revascularization with duplex ultrasonography

PubMed Central

Taylor, David C.; Houston, Gordon T.M.; Anderson, Caroline; Jameson, Margot; Popatia, Shelley

1996-01-01

Objective To evaluate the long-term anatomic results of renal revascularization procedures using duplex ultrasonography. Design A case series. Setting A university-affiliated hospital. Patients Twenty-five patients who had undergone renal percutaneous transluminal angioplasty (PTA) (18 arteries), renal bypass (10 arteries) and mesenteric bypass (6 arteries). The mean follow-up was 22 months (range from 3 to 48 months) for those who underwent renal PTA, 23 months (range from 1.5 to 70 months) for those who underwent renal bypass and 34 months (range from 8 to 144 months) for those who underwent mesenteric bypass. Main Outcome Measures Patency rates for the three procedures as assessed by duplex ultrasonography. Results Duplex ultrasonography demonstrated patency without stenosis after renal and mesenteric artery revascularization in 14 arteries subjected to renal PTA, 9 arteries subjected to renal bypass and 6 arteries subjected to mesenteric bypass. Three arteries that had renal PTA had recurrent vessel stenosis and one had occlusion. One artery that had renal bypass showed occlusion. Conclusions Renal PTA, renal bypass and mesenteric bypass are durable procedures at 2 years of follow-up, and duplex ultrasonography is a valuable method for assessing the patency of arteries after renal and mesenteric revascularization. PMID:8599785

Heart valves from polyester fibers: a preliminary 6-month in vivo study.

PubMed

Vaesken, Antoine; Pelle, Anne; Pavon-Djavid, Graciela; Rancic, Jeanne; Chakfe, Nabil; Heim, Frederic

2018-06-27

Transcatheter aortic valve implantation (TAVI) has become a popular alternative technique to surgical valve replacement for critical patients. Biological valve tissue has been used in TAVI procedures for over a decade, with over 150,000 implantations to date. However, with only 6 years of follow up, little is known about the long-term durability of biological tissue. Moreover, the high cost of tissue harvesting and chemical treatment procedures favor the development of alternative synthetic valve leaflet materials. In that context, textile polyester [polyethylene terephthalate (PET)] could be considered as an interesting candidate to replace the biological valve leaflets in TAVI procedures. However, no result is available in the literature about the behavior of textile once in contact with biological tissue in the valve position. The interaction of synthetic textile material with living tissues should be comparable to biological tissue. The purpose of this preliminary work is to compare the in vivo performances of various woven textile PET valves over a 6-month period in order to identify favorable textile construction features. In vivo results indicate that fibrosis as well as calcium deposit can be limited with an appropriate material design.

Adhesive groups and how they relate to the durability of bonded wood

Treesearch

Charles R. Frihart

2009-01-01

There is a need to develop models that evaluate the interaction of wood adhesives at the macroscopic level to explain observations on the durability of bonded wood laminate products with changing moisture conditions. This paper emphasizes a model that relates durability to strain on the bondline caused by wood swelling. The effect of this strain is discussed in...

Moisture Sorption, Biological Durability, and Mechanical Performance of WPC Containing Modified Wood and Polylactates

Treesearch

B. Kristoffer Segerholm; Rebecca E. Ibach; Mats Westin

2012-01-01

Biological durability is an important feature for wood-plastic composites (WPC) intended for outdoor applications. One route to achieving WPC products with increased biological durability is to use wood preservative agents in the formulation of the WPC. Another option could be to use a chemically modified wood component that already exhibits increased resistance to...

76 FR 35950 - Agency Information Collection Activity (Living Will and Durable Power of Attorney for Health Care...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-20

... (Living Will and Durable Power of Attorney for Health Care) Under OMB Review AGENCY: Department of... INFORMATION Title: Living Will and Durable Power of Attorney for Health Care, VA Form 10-0137. OMB Control... admitted to a VA medical facility complete VA Form 10-0137 to appoint a health care agent to make decision...

Durability as integral characteristic of concrete

NASA Astrophysics Data System (ADS)

Suleymanova, L. A.; Pogorelova, I. A.; Suleymanov, K. A.; Kirilenko, S. V.; Marushko, M. V.

2018-03-01

The carried-out research provides insight into the internal bonds energy in material as the basis of its durability, deformability, integrity and resistance to different factors (combined effects of external loadings and (or) environment), into the limits of technical possibilities, durability and physical reality of the process of concrete deterioration, which allows designing reliable and cost-effective ferroconcrete constructions for different purposes.

Preparation of durable hydrophobic cellulose fabric from water glass and mixed organosilanes

NASA Astrophysics Data System (ADS)

Shang, Song-Min; Li, Zhengxiong; Xing, Yanjun; Xin, John H.; Tao, Xiao-Ming

2010-12-01

Durable superhydrophobic cellulose fabric was prepared from water glass and n-octadecyltriethoxysilane (ODTES) with 3-glycidyloxypropyltrimethoxysilane (GPTMS) as crosslinker by sol-gel method. The result showed that the addition of GPTMS could result in a better fixation of silica coating from water glass on cellulose fabric. The silanization of hydrolyzed ODTES at different temperatures and times was studied and optimized. The results showed that silanization time was more important than temperature in forming durable hydrophobic surface. The durability of superhydrophobicity treatment was analyzed by XPS. As a result, the superhydrophobic cotton treated under the optimal condition still remained hydrophobic properties after 50 washing cycles.

Quantitative Resistance to Plant Pathogens in Pyramiding Strategies for Durable Crop Protection.

PubMed

Pilet-Nayel, Marie-Laure; Moury, Benoît; Caffier, Valérie; Montarry, Josselin; Kerlan, Marie-Claire; Fournet, Sylvain; Durel, Charles-Eric; Delourme, Régine

2017-01-01

Quantitative resistance has gained interest in plant breeding for pathogen control in low-input cropping systems. Although quantitative resistance frequently has only a partial effect and is difficult to select, it is considered more durable than major resistance (R) genes. With the exponential development of molecular markers over the past 20 years, resistance QTL have been more accurately detected and better integrated into breeding strategies for resistant varieties with increased potential for durability. This review summarizes current knowledge on the genetic inheritance, molecular basis, and durability of quantitative resistance. Based on this knowledge, we discuss how strategies that combine major R genes and QTL in crops can maintain the effectiveness of plant resistance to pathogens. Combining resistance QTL with complementary modes of action appears to be an interesting strategy for breeding effective and potentially durable resistance. Combining quantitative resistance with major R genes has proven to be a valuable approach for extending the effectiveness of major genes. In the plant genomics era, improved tools and methods are becoming available to better integrate quantitative resistance into breeding strategies. Nevertheless, optimal combinations of resistance loci will still have to be identified to preserve resistance effectiveness over time for durable crop protection.

Temperature induced effects on the durability of MR fluids

NASA Astrophysics Data System (ADS)

Wiehe, A.; Kieburg, C.; Maas, J.

2013-02-01

Although commercial MR fluids exist for quite some time now and the feasibility as well as the advantages of the MR technology have been demonstrated for several applications by a variety of MR actuator prototypes, a sustainable market break-through of brake and clutch applications utilizing the shear mode is still missing. Essential impediments are the marginal knowledge about the durability of the MR technology. To overcome this situation, a long-term measurement system was developed for the durability analysis of MR fluid formulations within a technical relevant scale with respect to the volume of MR fluid and the transmitted torque. The focus of the presented series of measurements is given to the analysis of temperature induced effects on the durability. In this context four different failure indicators can be distinguished, namely an apparent negative viscosity, deviations in torque data obtained from different measurements as well as a pressure increase and a drop in the on-state torque. The measurement data of the present durability experiments indicate a significant dependency of the attainable energy intake density on the temperature. The aim of such durability tests is to establish a reliable data base for the industry to estimate the life-time of MR devices.

Combining Selective Pressures to Enhance the Durability of Disease Resistance Genes.

PubMed

2016-01-01

The efficacy of disease resistance genes in plants decreases over time because of the selection of virulent pathogen genotypes. A key goal of crop protection programs is to increase the durability of the resistance conferred by these genes. The spatial and temporal deployment of plant disease resistance genes is considered to be a major factor determining their durability. In the literature, four principal strategies combining resistance genes over time and space have been considered to delay the evolution of virulent pathogen genotypes. We reviewed this literature with the aim of determining which deployment strategy results in the greatest durability of resistance genes. Although theoretical and empirical studies comparing deployment strategies of more than one resistance gene are very scarce, they suggest that the overall durability of disease resistance genes can be increased by combining their presence in the same plant (pyramiding). Retrospective analyses of field monitoring data also suggest that the pyramiding of disease resistance genes within a plant is the most durable strategy. By extension, we suggest that the combination of disease resistance genes with other practices for pathogen control (pesticides, farming practices) may be a relevant management strategy to slow down the evolution of virulent pathogen genotypes.

The Physiology and Molecular Underpinnings of the Effects of Bariatric Surgery on Obesity and Diabetes.

PubMed

Evers, Simon S; Sandoval, Darleen A; Seeley, Randy J

2017-02-10

Bariatric surgeries, such as Roux-en-Y gastric bypass and vertical sleeve gastrectomy, produce significant and durable weight loss in both humans and rodents. Recently, these surgical interventions have also been termed metabolic surgery because they result in profound metabolic improvements that often surpass the expected improvement due to body weight loss alone. In this review we focus on the weight-loss independent effects of bariatric surgery, which encompass energy expenditure and macronutrient preference, the luminal composition of the gut (i.e., the microbiota and bile acids), the transformation of the gastrointestinal lining, increases in postprandial gut hormone secretions, glycemic control, pancreas morphology, and micronutrient and mineral absorption. Taken together, these data point to several important physiological changes that contribute to the profound benefits of these surgical procedures. Identifying the underlying molecular mechanisms for these physiological effects will allow better utilization of these existing procedures to help patients and develop new treatments that harness these surgical effects with less invasive interventions.

An evaluation of the generalization and maintenance of functional communication and self-control skills with preschoolers.

PubMed

Luczynski, Kevin C; Hanley, Gregory P; Rodriguez, Nicole M

2014-01-01

The preschool life skills (PLS) program (Hanley, Heal, Tiger, & Ingvarsson, 2007; Luczynski & Hanley, 2013) involves teaching social skills as a means of decreasing and preventing problem behavior. However, achieving durable outcomes as children transition across educational settings depend on the generalization and long-term maintenance of those skills. The purpose of this study was to evaluate procedures for promoting generalization and long-term maintenance of functional communication and self-control skills for 6 preschool children. When the children's social skills decreased across repeated observations during a generalization assessment, we incorporated modifications to the teaching procedures. However, the effects of the modifications were variable across skills and children. Satisfactory generalization was observed only after the teacher was informed of the target skills and teaching strategies. Maintenance of most social skills was observed 3 months after teaching was discontinued. We discuss the importance of improving child and teacher behavior to promote generalization and maintenance of important social skills. © Society for the Experimental Analysis of Behavior.

Roux-en-Y Gastric Bypass and Vertical Banded Gastroplasty Induce Long-Term Changes on the Human Gut Microbiome Contributing to Fat Mass Regulation

PubMed Central

Tremaroli, Valentina; Karlsson, Fredrik; Werling, Malin; Ståhlman, Marcus; Kovatcheva-Datchary, Petia; Olbers, Torsten; Fändriks, Lars; le Roux, Carel W.; Nielsen, Jens; Bäckhed, Fredrik

2015-01-01

Summary Bariatric surgery is currently the most effective procedure for the treatment of obesity. Given the role of the gut microbiota in regulating host metabolism and adiposity, we investigated the long-term effects of bariatric surgery on the microbiome of patients randomized to Roux-en-Y gastric bypass or vertical banded gastroplasty and matched for weight and fat mass loss. The two surgical procedures induced similar and durable changes on the gut microbiome that were not dependent on body mass index and resulted in altered levels of fecal and circulating metabolites compared with obese controls. By colonizing germ-free mice with stools from the patients, we demonstrated that the surgically altered microbiota promoted reduced fat deposition in recipient mice. These mice also had a lower respiratory quotient, indicating decreased utilization of carbohydrates as fuel. Our results suggest that the gut microbiota may play a direct role in the reduction of adiposity observed after bariatric surgery. PMID:26244932

Surgical strategies for pediatric epilepsy

PubMed Central

Guan, Jian; Karsy, Michael; Ducis, Katrina

2016-01-01

Pediatric epilepsy is a debilitating condition that impacts millions of patients throughout the world. Approximately 20–30% of children with recurrent seizures have drug-resistant epilepsy (DRE). For these patients, surgery offers the possibility of not just seizure freedom but significantly improved neurocognitive and behavioral outcomes. The spectrum of surgical options is vast, ranging from outpatient procedures such as vagus nerve stimulation to radical interventions including hemispherectomy. The thread connecting all of these interventions is a common goal—seizure freedom, an outcome that can be achieved safely and durably in a large proportion of patients. In this review, we discuss many of the most commonly performed surgical interventions and describe the indications, complications, and outcomes specific to each. PMID:27186522

The other side of the safety coin. [aerospace operations

NASA Technical Reports Server (NTRS)

Roth, Gilbert L.

1986-01-01

The development, inspection and testing requirements for successful production and launch and safe operation of spaceflight hardware are discussed. Emphasis is placed on paying acute attention to malfunctions, which could be caused by contaminants (particles in docking rings), insufficiently durable materials (Orbiter brakes), etc. Generic and specific problems which occur in propulsion, avionics, mechanical and computer systems and in configuration management, manufacturing and process control efforts are explored. Case histories of deficiencies found in LOX fuel lines, contaminated hydraulic control systems, the Solar Maximum Mission thermal insulation grommets, are summarized. Thorough inspection and testing procedures and design change recording during manufacture of spacecraft components are identified as requisites for successful space missions.

Measure Guideline: Deep Energy Enclosure Retrofit for Double-Stud Walls

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loomis, H.; Pettit, B.

2015-06-01

This Measure Guideline describes a deep energy enclosure retrofit (DEER) solution that provides insulation to the interior of the wall assembly with the use of a double stud wall. The guide describes two approaches to retrofitting the existing the walls: one involving replacement of the existing cladding, and the other that leaves the existing cladding in place. It discusses the design principles related to the use of various insulation types, and provides strategies and procedures for implementing the double stud wall retrofit. It also evaluates important moisture-related and indoor air quality measures that need to be implemented to achieve amore » durable, high performance wall.« less

Total artificial heart implantation in a young Marfan syndrome patient.

PubMed

Rao, Prashant; Keenan, Jack B; Rajab, Taufiek K; Kim, Samuel; Smith, Richard; Amabile, Orazio; Khalpey, Zain

2018-03-01

Cardiovascular complications represent the leading cause of morbidity and mortality in patients with Marfan syndrome. Here, we describe a unique case where a total artificial heart was implanted in a young Marfan syndrome woman. A 22-year-old postpartum African American female with Marfan syndrome developed multiple severe valve dysfunction and biventricular failure that was refractory to medical management. She previously had a Bentall procedure for Type A aortic dissection and repair of a Type B dissection. We implanted a total artificial heart with a good outcome. Total artificial heart is a durable option for severe biventricular failure and multiple valvular dysfunction as a bridge to transplant in a young patient with Marfan syndrome.

Electrical design for origami solar panels and a small spacecraft test mission

NASA Astrophysics Data System (ADS)

Drewelow, James; Straub, Jeremy

2017-05-01

Efficient power generation is crucial to the design of spacecraft. Mass, volume, and other limitations prevent the use of traditional spacecraft support structures from being suitable for the size of solar array required for some missions. Folding solar panel / panel array systems, however, present a number of design challenges. This paper considers the electrical design of an origami system. Specifically, it considers how to provide low impedance, durable channels for the generated power and the electrical aspects of the deployment system and procedure. The ability to dynamically reconfigure the electrical configuration of the solar cells is also discussed. Finally, a small satellite test mission to demonstrate the technology is proposed, before concluding.

Surface modification of polyethylene by radiation-induced grafting for adhesive bonding. V. Comparison with other surface treatments. [Gamma radiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamakawa, S.; Yamamoto, F.

1980-01-01

Helium gas plasma treatment of low-density polyethylene (LDPE) yields much lower peel strength than oxidative treatment using chromic acid and oxygen gas plasma. The practical adhesion, the bondability retention, and the bond durability of oxidatively treated LDPE sheets, bonded with epoxy adhesives, have been compared with those of partially hydrolyzed LDPE-methyl acrylate surface grafts. The oxidized surfaces easily lose the bondability by light rubbing with tissue paper, solvent extraction, heat aging, and artificial weathering, whereas the grafted surfaces retain the bondability. The bondability loss is due to removal of the oxidized layer, and the bondability retention is due to retentionmore » of the surface homopolymer layer. Conventional antioxidants stabilize the grafted but not the oxidized surfaces against thermal oxidative degradation. The grafted LDPE joints have much higher bond durability in humid environments than those of the oxidized LDPE joints. The dry and wet peel strengths of oxidized LDPE joints are greatly improved by application of primers consisting of a base epoxy resin and organic solvents. An adhesion mechanism involving penetration of epoxy adhesives into the oxidized layers and subsequent reinforcement of the layers by curing of the penetrated epoxy is proposed. 5 figures, 5 tables.« less

Proton exchange membrane fuel cell model for aging predictions: Simulated equivalent active surface area loss and comparisons with durability tests

NASA Astrophysics Data System (ADS)

Robin, C.; Gérard, M.; Quinaud, M.; d'Arbigny, J.; Bultel, Y.

2016-09-01

The prediction of Proton Exchange Membrane Fuel Cell (PEMFC) lifetime is one of the major challenges to optimize both material properties and dynamic control of the fuel cell system. In this study, by a multiscale modeling approach, a mechanistic catalyst dissolution model is coupled to a dynamic PEMFC cell model to predict the performance loss of the PEMFC. Results are compared to two 2000-h experimental aging tests. More precisely, an original approach is introduced to estimate the loss of an equivalent active surface area during an aging test. Indeed, when the computed Electrochemical Catalyst Surface Area profile is fitted on the experimental measures from Cyclic Voltammetry, the computed performance loss of the PEMFC is underestimated. To be able to predict the performance loss measured by polarization curves during the aging test, an equivalent active surface area is obtained by a model inversion. This methodology enables to successfully find back the experimental cell voltage decay during time. The model parameters are fitted from the polarization curves so that they include the global degradation. Moreover, the model captures the aging heterogeneities along the surface of the cell observed experimentally. Finally, a second 2000-h durability test in dynamic operating conditions validates the approach.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coletti, Chiara, E-mail: chiara.coletti@studenti.u

During the firing of bricks, mineralogical and textural transformations produce an artificial aggregate characterised by significant porosity. Particularly as regards pore-size distribution and the interconnection model, porosity is an important parameter to evaluate and predict the durability of bricks. The pore system is in fact the main element, which correlates building materials and their environment (especially in cases of aggressive weathering, e.g., salt crystallisation and freeze-thaw cycles) and determines their durability. Four industrial bricks with differing compositions and firing temperatures were analysed with “direct” and “indirect” techniques, traditional methods (mercury intrusion porosimetry, hydric tests, nitrogen adsorption) and new analytical approachesmore » based on digital image reconstruction of 2D and 3D models (back-scattered electrons and computerised X-ray micro-Tomography, respectively). The comparison of results from different analytical methods in the “overlapping ranges” of porosity and the careful reconstruction of a cumulative curve, allowed overcoming their specific limitations and achieving better knowledge on the pore system of bricks. - Highlights: •Pore-size distribution and structure of the pore system in four commercial bricks •A multi-analytical approach combining “direct” and “indirect” techniques •Traditional methods vs. new approaches based on 2D/3D digital image reconstruction •The use of “overlapping ranges” to overcome the limitations of various techniques.« less

Impact of gastrectomy procedural complexity on surgical outcomes and hospital comparisons.

PubMed

Mohanty, Sanjay; Paruch, Jennifer; Bilimoria, Karl Y; Cohen, Mark; Strong, Vivian E; Weber, Sharon M

2015-08-01

Most risk adjustment approaches adjust for patient comorbidities and the primary procedure. However, procedures done at the same time as the index case may increase operative risk and merit inclusion in adjustment models for fair hospital comparisons. Our objectives were to evaluate the impact of surgical complexity on postoperative outcomes and hospital comparisons in gastric cancer surgery. Patients who underwent gastric resection for cancer were identified from a large clinical dataset. Procedure complexity was characterized using secondary procedure CPT codes and work relative value units (RVUs). Regression models were developed to evaluate the association between complexity variables and outcomes. The impact of complexity adjustment on model performance and hospital comparisons was examined. Among 3,467 patients who underwent gastrectomy for adenocarcinoma, 2,171 operations were distal and 1,296 total. A secondary procedure was reported for 33% of distal gastrectomies and 59% of total gastrectomies. Six of 10 secondary procedures were associated with adverse outcomes. For example, patients who underwent a synchronous bowel resection had a higher risk of mortality (odds ratio [OR], 2.14; 95% CI, 1.07-4.29) and reoperation (OR, 2.09; 95% CI, 1.26-3.47). Model performance was slightly better for nearly all outcomes with complexity adjustment (mortality c-statistics: standard model, 0.853; secondary procedure model, 0.858; RVU model, 0.855). Hospital ranking did not change substantially after complexity adjustment. Surgical complexity variables are associated with adverse outcomes in gastrectomy, but complexity adjustment does not affect hospital rankings appreciably. Copyright © 2015 Elsevier Inc. All rights reserved.

Durability of Aortic Valve Cusp Repair With and Without Annular Support.

PubMed

Zeeshan, Ahmad; Idrees, Jay J; Johnston, Douglas R; Rajeswaran, Jeevanantham; Roselli, Eric E; Soltesz, Edward G; Gillinov, A Marc; Griffin, Brian; Grimm, Richard; Hammer, Donald F; Pettersson, Gösta B; Blackstone, Eugene H; Sabik, Joseph F; Svensson, Lars G

2018-03-01

To determine the value of aortic valve repair rather than replacement for valve dysfunction, we assessed late outcomes of various repair techniques in the contemporary era. From January 2001 to January 2011, aortic valve repair was planned in 1,124 patients. Techniques involved commissural figure-of-8 suspension sutures (n = 63 [6.2%]), cusp repair with commissuroplasty (n = 481 [48%]), debridement (n = 174 [17%]), free-margin plication (n = 271 [27%]) or resection (n = 75) or both, or annulus repair with resuspension (n = 230 [23%]), root reimplantation (n = 252 [25%]), or remodeling (n = 35 [3.5%]). Planned repair was aborted for replacement in 115 patients (10%); risk factors included greater severity of aortic regurgitation (AR; p = 0.0002) and valve calcification (p < 0.0001). In-hospital outcomes for the remaining 1,009 patients included death (12 [1.2%]), stroke (13 [1.3%]), and reoperation for valve dysfunction (14 [1.4%]). Freedom from aortic valve reoperation at 1, 5, and 10 years was 97%, 93%, and 90%, respectively. Figure-of-8 suspension sutures, valve resuspension, and root repair and replacement were least likely to require reoperation; cusp repair with commissural sutures, plication, and commissuroplasty was most likely (p < 0.05). Survival at 1, 5, and 10 years was 96%, 92%, and 83%. Immediate postoperative AR grade was none-mild (94%), moderate (5%), and severe (1%). At 10 years after repair, AR grade was none (20%), mild (33%), moderate (26%), and severe (21%). Patients undergoing root procedures were less likely to have higher-grade postoperative AR (p < 0.0001). Valve repair is effective and durable for treating aortic valve dysfunction. Greater severity of AR preoperatively is associated with higher likelihood of repair failure. Commissural figure-of-8 suspension sutures and repair with annular support have the best long-term durability. Copyright © 2018 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Treatment Effect of Drug-Coated Balloons Is Durable to 3 Years in the Femoropopliteal Arteries

PubMed Central

Laird, John R.; Tepe, Gunnar; Brodmann, Marianne; Zeller, Thomas; Scheinert, Dierk; Metzger, Christopher; Micari, Antonio; Sachar, Ravish; Jaff, Michael R.; Wang, Hong; Hasenbank, Melissa S.; Krishnan, Prakash

2018-01-01

Background— Randomized controlled trials have reported favorable 1-year outcomes with drug-coated balloons (DCBs) for the treatment of symptomatic peripheral arterial disease when compared with standard percutaneous transluminal angioplasty (PTA). Evidence remains limited on the durability of the treatment effect with DCBs in the longer term. Methods and Results— IN.PACT SFA is a single-blind, randomized trial (Randomized Trial of IN.PACT Admiral Paclitaxel-Coated Percutaneous Transluminal Angioplasty [PTA] Balloon Catheter vs Standard PTA for the Treatment of Atherosclerotic Lesions in the Superficial Femoral Artery [SFA] and/or Proximal Popliteal Artery [PPA]) that enrolled 331 patients with symptomatic (Rutherford 2–4) femoropopliteal lesions up to 18 cm in length. Patients were randomized 2:1 to receive treatment with DCB or PTA. The 36-month assessments included primary patency, freedom from clinically driven target lesion revascularization, major adverse events, and functional outcomes. At 36 months, primary patency remained significantly higher among patients treated with DCB compared with PTA (69.5% versus 45.1%; log rank P<0.001). The rates of clinically driven target lesion revascularization were 15.2% and 31.1% (P=0.002) for the DCB and PTA groups, respectively. Functional outcomes were similarly improved between treatment groups even though subjects in the DCB group required significantly fewer reinterventions versus those in the PTA group (P<0.001 for target lesion revascularization, P=0.001 for target vessel revascularization). There were no device- or procedure-related deaths as adjudicated by an independent Clinical Events Committee. Conclusions— Three-year results demonstrate a durable and superior treatment effect among patients treated with DCB versus standard PTA, with significantly higher primary patency and lower clinically driven target lesion revascularization, resulting in similar functional improvements with reduced need for repeat interventions. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifiers: NCT01175850 for IN.PACT SFA phase I in the European Union and NCT01566461 for IN.PACT SFA phase II in the United States. PMID:29326153

ITO-MgF2 Film Development for PowerSphere Polymer Surface Protection

NASA Technical Reports Server (NTRS)

Hambourger, Paul D.; Kerslake, Thomas W.; Waters, Deborah L.

2004-01-01

Multi-kilogram class microsatellites with a PowerSphere electric power system are attractive for fulfilling a variety of potential NASA missions. However, PowerSphere polymer surfaces must be coated with a film that has suitable electrical sheet resistivity for electrostatic discharge control, be resistant to atomic oxygen attack, be transparent to ultraviolet light for composite structure curing and resist ultraviolet light induced darkening for efficient photovoltaic cell operation. In addition, the film must be tolerant of polymer layer folding associated with launch stowage of PowerSphere inflatable structures. An excellent film material candidate to meet these requirements is co-sputtered, indium oxide (In2O3) - tin oxide (SnO2), known as 'ITO', and magnesium fluoride (MgF2). While basic ITO-MgF2 film properties have been the subject of research over the last decade, further research is required in the areas of film durability for space-inflatable applications and precise film property control for large scale commercial production. In this paper, the authors present film durability results for a folded polymer substrate and film resistance to vacuum UV darkening. The authors discuss methods and results in the area of film sheet resistivity measurement and active control, particularly dual-channel, plasma emission line measurement of ITO and MgF2 plasma sources. ITO-MgF2 film polymer coupon preparation is described as well as film deposition equipment, procedures and film characterization. Durability testing methods are also described. The pre- and post-test condition of the films is assessed microscopically and electrically. Results show that an approx. 500A ITO-18vol% MgF2 film is a promising candidate to protect PowerSphere polymer surfaces for Earth orbit missions. Preliminary data also indicate that in situ film measurement methods are promising for active film resistivity control in future large scale production. Future film research plans are also discussed.

Advanced Design and Optimization of High Performance Combatant Craft: Material Testing and Computational Tools

DTIC Science & Technology

2012-05-31

inherently shock-absorbent, and more durable than conventional materials. Despite these initial demonstration successes, there are still barriers that need...to deliver boats that are stronger, lighter, inherently shock‐absorbent, and more durable than those manufactured with conventional materials...and more durable than conventional materials (e.g. aluminum). Further, prior research by the University of Maine, Virginia Tech, and others has

A Simple Laparoscopic Procedure to Restore a Normal Vaginal Length After Colpohysterectomy With Large Upper Colpectomy for Cervical and/or Vaginal Neoplasia.

PubMed

Leblanc, Eric; Bresson, Lucie; Merlot, Benjamin; Puga, Marco; Kridelka, Frederic; Tsunoda, Audrey; Narducci, Fabrice

2016-01-01

Colpohysterectomy is sometimes associated with a large upper colpectomy resulting in a shortened vagina, potentially impacting sexual function. We report on a preliminary experience of a laparoscopic colpoplasty to restore a normal vaginal length. Patients with shortened vaginas after a laparoscopic colpohysterectomy were considered for a laparoscopic modified Davydov's procedure to create a new vaginal vault using the peritoneum of the rectum and bladder. From 2010 to 2014, 8 patients were offered this procedure, after informed preoperative consent. Indications were 2 extensive recurrent vaginal intraepithelial neoplasias grade 3 and 6 radical hysterectomies for cervical cancer. Mean vaginal length before surgery was 3.8 cm (standard deviation, 1.6). Median operative time was 50 minutes (range, 45-90). Blood loss was minimal (50-100 mL). No perioperative complications occurred. Median vaginal length at discharge was 11.3 cm (range, 9-13). Sexual intercourse could be resumed around 10 weeks after surgery. At a median follow-up of 33.8 months (range, 2.4-51.3), 6 patients remained sexually active but 2 had stopped. Although this experience is small, this laparoscopic modified Davydov's procedure seems to be an effective procedure, adaptable to each patient's anatomy. If the initial postoperative regular self-dilatation is carefully observed, vaginal patency is durably restored and enables normal sexual function. Copyright © 2016 AAGL. Published by Elsevier Inc. All rights reserved.

Structural Analyses of Stirling Power Convertor Heater Head for Long-Term Reliability, Durability, and Performance

NASA Technical Reports Server (NTRS)

Halford, Gary R.; Shah, Ashwin; Arya, Vinod K.; Krause, David L.; Bartolotta, Paul A.

2002-01-01

Deep-space missions require onboard electric power systems with reliable design lifetimes of up to 10 yr and beyond. A high-efficiency Stirling radioisotope power system is a likely candidate for future deep-space missions and Mars rover applications. To ensure ample durability, the structurally critical heater head of the Stirling power convertor has undergone extensive computational analyses of operating temperatures (up to 650 C), stresses, and creep resistance of the thin-walled Inconel 718 bill of material. Durability predictions are presented in terms of the probability of survival. A benchmark structural testing program has commenced to support the analyses. This report presents the current status of durability assessments.

Stirling engine - Approach for long-term durability assessment

NASA Technical Reports Server (NTRS)

Tong, Michael T.; Bartolotta, Paul A.; Halford, Gary R.; Freed, Alan D.

1992-01-01

The approach employed by NASA Lewis for the long-term durability assessment of the Stirling engine hot-section components is summarized. The approach consists of: preliminary structural assessment; development of a viscoplastic constitutive model to accurately determine material behavior under high-temperature thermomechanical loads; an experimental program to characterize material constants for the viscoplastic constitutive model; finite-element thermal analysis and structural analysis using a viscoplastic constitutive model to obtain stress/strain/temperature at the critical location of the hot-section components for life assessment; and development of a life prediction model applicable for long-term durability assessment at high temperatures. The approach should aid in the provision of long-term structural durability and reliability of Stirling engines.

Durable silver coating for mirrors

DOEpatents

Wolfe, Jesse D.; Thomas, Norman L.

2000-01-01

A durable multilayer mirror includes reflective layers of aluminum and silver and has high reflectance over a broad spectral range from ultraviolet to visible to infrared. An adhesion layer of a nickel and/or chromium alloy or nitride is deposited on an aluminum surface, and a thin layer of silver is then deposited on the adhesion layer. The silver layer is protected by a passivation layer of a nickel and/or chromium alloy or nitride and by one or more durability layers made of metal oxides and typically a first layer of metal nitride. The durability layers may include a composite silicon aluminum nitride and an oxinitride transition layer to improve bonding between nitride and oxide layers.