Lithium Ion Testing at NSWC Crane in Support of NASA Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Brown, Harry; Jung, David; Lee, Leonine

2010-01-01

This viewgraph presentation reviews Lithium Ion Cell testing at the Naval Surface Warfare Center in Crane, India. The contents include: 1) Quallion 15 Ahr Lithium-Ion Cells, LEO Life Cycle Test; 2) Lithion 50 Ahr Lithium-Ion Cells, LEO Life Cycle Test; 3) ABSL 5 Ahr Lithium-Ion Battery, LRO-LLO Life Cycle Test, SDO-GEO Life Cycle Test; and 4) A123 40 Ahr Lithium-Ion Battery, GPM Life Cycle Test, MMS Life Cycle Test.

Test of US Federal Life Cycle Inventory Data Interoperability

EPA Science Inventory

Life cycle assessment practitioners must gather data from a variety of sources. For modeling activities in the US, practitioners may wish to use life cycle inventory data from public databases and libraries provided by US government entities. An exercise was conducted to test if ...

Fatigue limit and Hysteresis Behavior of Type 304L Stainless Steel in Air and PWR Water, at 150°C and 300°C

NASA Astrophysics Data System (ADS)

Solomon, H. D.; Amzallag, C.; Vallee, A. J.; DeLair, R. E.

This is a study of the 107 cycle fatigue limit of Type 304L Stainless Steel, as measured in fully reversed (R=-1) load-controlled tests, at 150°C and 300°C, in air and PWR water. The staircase method was used to determine the fatigue limit. The tests run here utilized a cycle frequency of 1.818Hz and are compared to other tests from the literature that were run at 30Hz. The fatigue limit measured in the tests run at the high frequency was higher than that measured here. This is explained by measurements of the strain developed during cycling, using the different cycle frequencies. The tests run at the higher frequencies yielded lower strains for a given stress and, as expected, this resulted in higher fatigue limits. Using 107 cycles to define a run-out also led to a lower fatigue limit. These results are important as most previous fatigue limit measurements utilized 106 cycles or less to define a run-out, and when lives as long as 107 cycles are used the tests are generally run at high cycle frequencies, thus leading to higher fatigue limits than those measured here.

High temperature, low cycle fatigue of copper-base alloys in argon. Part 3: Zirconium-copper; thermal-mechanical strain cycling, hold-time and notch fatigue results

NASA Technical Reports Server (NTRS)

Conway, J. B.; Stentz, R. H.; Berling, J. T.

1973-01-01

The low-cycle fatigue characteristics of smooth bar and notched bar specimens (hourglass shape) of zirconium-copper, 1/2 Hard, material (R-2 Series) were evaluated at room temperature in axial strain control. Over the fatigue life range from about 300 to 3000 cycles the ratio of fatigue life for smooth bar to fatigue life for notched bar remained constant at a value of about 6.0. Some additional hold-time data for the R-2 alloy tested in argon at 538 C are reported. An analysis of the relaxation data obtained in these hold-time tests is also reported and it is shown that these data yield a fairly consistent correlation in terms of instantaneous stress rate divided by instantaneous stress. Two thermal-mechanical strain cycling tests were also performed using a cyclic frequency of 4.5 cycles per hour and a temperature cycling interval from 260 to 538 C. The fatigue life values in these tests were noticeably lower than that observed in isothermal tests at 538 C.

40 CFR 90.410 - Engine test cycle.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine test cycle. 90.410 Section 90... Procedures § 90.410 Engine test cycle. (a) Follow the appropriate 6-mode test cycle for Class I, I-B and II engines and 2-mode test cycle for Class I-A, III, IV, and V engines when testing spark-ignition engines...

Non-Nuclear Validation Test Results of a Closed Brayton Cycle Test-Loop

NASA Astrophysics Data System (ADS)

Wright, Steven A.

2007-01-01

Both NASA and DOE have programs that are investigating advanced power conversion cycles for planetary surface power on the moon or Mars, or for next generation nuclear power plants on earth. Although open Brayton cycles are in use for many applications (combined cycle power plants, aircraft engines), only a few closed Brayton cycles have been tested. Experience with closed Brayton cycles coupled to nuclear reactors is even more limited and current projections of Brayton cycle performance are based on analytic models. This report describes and compares experimental results with model predictions from a series of non-nuclear tests using a small scale closed loop Brayton cycle available at Sandia National Laboratories. A substantial amount of testing has been performed, and the information is being used to help validate models. In this report we summarize the results from three kinds of tests. These tests include: 1) test results that are useful for validating the characteristic flow curves of the turbomachinery for various gases ranging from ideal gases (Ar or Ar/He) to non-ideal gases such as CO2, 2) test results that represent shut down transients and decay heat removal capability of Brayton loops after reactor shut down, and 3) tests that map a range of operating power versus shaft speed curve and turbine inlet temperature that are useful for predicting stable operating conditions during both normal and off-normal operating behavior. These tests reveal significant interactions between the reactor and balance of plant. Specifically these results predict limited speed up behavior of the turbomachinery caused by loss of load, the conditions for stable operation, and for direct cooled reactors, the tests reveal that the coast down behavior during loss of power events can extend for hours provided the ultimate heat sink remains available.

NASA welding assessment program

NASA Technical Reports Server (NTRS)

Stofel, E. J.

1984-01-01

A long duration test has been conducted for comparing various methods of attaching electrical interconnects to solar cells for near Earth orbit spacecraft. Representative solar array modules have been thermally cycled for 36,000 cycles between -80 and +80 C on this JPL and NASA Lewis Research Center sponsored work. This test simulates the environmental stress of more than 6 years on a near Earth spacecraft as it cycles in and out of the Earth's shadow. Evaluations of the integrity of these modules were made by visual and by electrical examinations before starting the cycling and then at periodic intervals during the cycling tests. Modules included examples of parallel gap and of ultrasonic welding, as well as soldering. The materials and fabrication processes are state of the art, suitable for forming large solar arrays of spacecraft quality. The modules survived his extensive cycling without detectable degradation in their ability to generate power under sunlight illumination.

40 CFR 89.410 - Engine test cycle.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine test cycle. 89.410 Section 89... Procedures § 89.410 Engine test cycle. (a) Emissions shall be measured using one of the test cycles specified...) through (a)(4) of this section. These cycles shall be used to test engines on a dynamometer. (1) The 8...

Statistical damage constitutive model for rocks subjected to cyclic stress and cyclic temperature

NASA Astrophysics Data System (ADS)

Zhou, Shu-Wei; Xia, Cai-Chu; Zhao, Hai-Bin; Mei, Song-Hua; Zhou, Yu

2017-10-01

A constitutive model of rocks subjected to cyclic stress-temperature was proposed. Based on statistical damage theory, the damage constitutive model with Weibull distribution was extended. Influence of model parameters on the stress-strain curve for rock reloading after stress-temperature cycling was then discussed. The proposed model was initially validated by rock tests for cyclic stress-temperature and only cyclic stress. Finally, the total damage evolution induced by stress-temperature cycling and reloading after cycling was explored and discussed. The proposed constitutive model is reasonable and applicable, describing well the stress-strain relationship during stress-temperature cycles and providing a good fit to the test results. Elastic modulus in the reference state and the damage induced by cycling affect the shape of reloading stress-strain curve. Total damage induced by cycling and reloading after cycling exhibits three stages: initial slow increase, mid-term accelerated increase, and final slow increase.

40 CFR 86.1360-2007 - Supplemental emission test; test cycle and procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Supplemental emission test; test cycle... ENGINES (CONTINUED) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1360-2007 Supplemental emission test; test cycle and procedures. The...

Integration and validation testing for PhEDEx, DBS and DAS with the PhEDEx LifeCycle agent

NASA Astrophysics Data System (ADS)

Boeser, C.; Chwalek, T.; Giffels, M.; Kuznetsov, V.; Wildish, T.

2014-06-01

The ever-increasing amount of data handled by the CMS dataflow and workflow management tools poses new challenges for cross-validation among different systems within CMS experiment at LHC. To approach this problem we developed an integration test suite based on the LifeCycle agent, a tool originally conceived for stress-testing new releases of PhEDEx, the CMS data-placement tool. The LifeCycle agent provides a framework for customising the test workflow in arbitrary ways, and can scale to levels of activity well beyond those seen in normal running. This means we can run realistic performance tests at scales not likely to be seen by the experiment for some years, or with custom topologies to examine particular situations that may cause concern some time in the future. The LifeCycle agent has recently been enhanced to become a general purpose integration and validation testing tool for major CMS services. It allows cross-system integration tests of all three components to be performed in controlled environments, without interfering with production services. In this paper we discuss the design and implementation of the LifeCycle agent. We describe how it is used for small-scale debugging and validation tests, and how we extend that to large-scale tests of whole groups of sub-systems. We show how the LifeCycle agent can emulate the action of operators, physicists, or software agents external to the system under test, and how it can be scaled to large and complex systems.

Development of engine activity cycles for the prime movers of unconventional natural gas well development.

PubMed

Johnson, Derek; Heltzel, Robert; Nix, Andrew; Barrow, Rebekah

2017-03-01

With the advent of unconventional natural gas resources, new research focuses on the efficiency and emissions of the prime movers powering these fleets. These prime movers also play important roles in emissions inventories for this sector. Industry seeks to reduce operating costs by decreasing the required fuel demands of these high horsepower engines but conducting in-field or full-scale research on new technologies is cost prohibitive. As such, this research completed extensive in-use data collection efforts for the engines powering over-the-road trucks, drilling engines, and hydraulic stimulation pump engines. These engine activity data were processed in order to make representative test cycles using a Markov Chain, Monte Carlo (MCMC) simulation method. Such cycles can be applied under controlled environments on scaled engines for future research. In addition to MCMC, genetic algorithms were used to improve the overall performance values for the test cycles and smoothing was applied to ensure regression criteria were met during implementation on a test engine and dynamometer. The variations in cycle and in-use statistics are presented along with comparisons to conventional test cycles used for emissions compliance. Development of representative, engine dynamometer test cycles, from in-use activity data, is crucial in understanding fuel efficiency and emissions for engine operating modes that are different from cycles mandated by the Code of Federal Regulations. Representative cycles were created for the prime movers of unconventional well development-over-the-road (OTR) trucks and drilling and hydraulic fracturing engines. The representative cycles are implemented on scaled engines to reduce fuel consumption during research and development of new technologies in controlled laboratory environments.

Effects of thermal cycling on surface roughness, hardness and flexural strength of polymethylmethacrylate and polyamide denture base resins.

PubMed

Ayaz, Elif Aydoğan; Bağış, Bora; Turgut, Sedanur

2015-10-16

The purpose of this study was to evaluate the effects of thermal cycling on the surface roughness, hardness and flexural strength of denture resins. Polyamide (PA; Deflex and Valplast) and polymethylmethacrylate (PMMA; QC-20 and Acron MC) denture materials were selected. A total of 180 specimens were fabricated and then divided into 3 groups. The first group (group 1) acted as a control and was not thermocycled. The second group (group 2) was subjected to thermocycling for 10,000 cycles in artificial saliva and 5,000 cycles in distilled water. The last group (group 3) was thermocycled for 20,000 cycles in artificial saliva and 10,000 cycles in distilled water. The surface roughness were measured with a profilometer. The hardness of the resins were measured with a Vickers Hardness Tester using a 100-gf load. The flexural strength test was performed using the universal test machine with a crosshead speed of 5 mm/min. Data were analyzed using statistical software. The results of the measurements in the 3 different tests were analyzed by Kruskal-Wallis test with Bonferroni correction. Multiple comparisons were made by Conover and Wilcoxon tests. There was a significant difference between the PMMA and PA groups in terms of surface roughness, hardness and transverse strength before and after thermal cycling (p<0.001). Thermal cycling did not change the surface roughness, hardness and flexural strength values of either the PMMA or PA group (p>0.001).

40 CFR 86.1333-90 - Transient test cycle generation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Transient test cycle generation. 86...) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1333-90 Transient test cycle generation. (a) The heavy-duty transient engine cycles for Otto...

Performance tests of a two phase ejector

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

Harrell, G.S.; Kornhauser, A.A.

1995-12-31

The ejector expansion refrigeration cycle is a modified vapor compression cycle in which a two phase ejector is used to recover a portion of the work otherwise lost in the expansion valve. The ejector improves cycle performance by increasing compressor inlet pressure and by lowering the quality of liquid entering the evaporator. Theoretically, a cooling COP improvement of approximately 23% is achievable for a typical refrigerating cycle and an ideal ejector. If the ejector performed as well as typical single phase ejectors an improvement of 12% could be achieved. Previous tests have demonstrated a smaller 3.7% improvement; the difference ismore » in the poor performance of the two phase ejector. The purpose of this research is to understand the operating characteristics of the two phase ejector and to devise design improvements. A two phase ejector test rig has been constructed and tested. Preliminary data show performance superior to previously tested two phase ejectors, but still inferior to single phase ejectors. Ejector performance corresponds to refrigeration cycle COP improvements ranging from 3.9% to 7.6%.« less

40 CFR 1033.520 - Alternative ramped modal cycles.

Code of Federal Regulations, 2014 CFR

2014-07-01

... warm it up. Then follow the provisions of 40 CFR part 1065, subpart F for general pre-test procedures (including engine and sampling system pre-conditioning). (d) Begin the test by operating the locomotive over the pre-test portion of the cycle. For locomotives not equipped with catalysts, you may begin the test...

40 CFR 1033.520 - Alternative ramped modal cycles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... warm it up. Then follow the provisions of 40 CFR part 1065, subpart F for general pre-test procedures (including engine and sampling system pre-conditioning). (d) Begin the test by operating the locomotive over the pre-test portion of the cycle. For locomotives not equipped with catalysts, you may begin the test...

40 CFR 1033.520 - Alternative ramped modal cycles.

Code of Federal Regulations, 2013 CFR

2013-07-01

... warm it up. Then follow the provisions of 40 CFR part 1065, subpart F for general pre-test procedures (including engine and sampling system pre-conditioning). (d) Begin the test by operating the locomotive over the pre-test portion of the cycle. For locomotives not equipped with catalysts, you may begin the test...

40 CFR 1033.520 - Alternative ramped modal cycles.

Code of Federal Regulations, 2011 CFR

2011-07-01

... warm it up. Then follow the provisions of 40 CFR part 1065, subpart F for general pre-test procedures (including engine and sampling system pre-conditioning). (d) Begin the test by operating the locomotive over the pre-test portion of the cycle. For locomotives not equipped with catalysts, you may begin the test...

Solar panel thermal cycling testing by solar simulation and infrared radiation methods

NASA Technical Reports Server (NTRS)

Nuss, H. E.

1980-01-01

For the solar panels of the European Space Agency (ESA) satellites OTS/MAROTS and ECS/MARECS the thermal cycling tests were performed by using solar simulation methods. The performance data of two different solar simulators used and the thermal test results are described. The solar simulation thermal cycling tests for the ECS/MARECS solar panels were carried out with the aid of a rotatable multipanel test rig by which simultaneous testing of three solar panels was possible. As an alternative thermal test method, the capability of an infrared radiation method was studied and infrared simulation tests for the ultralight panel and the INTELSAT 5 solar panels were performed. The setup and the characteristics of the infrared radiation unit using a quartz lamp array of approx. 15 sq and LN2-cooled shutter and the thermal test results are presented. The irradiation uniformity, the solar panel temperature distribution, temperature changing rates for both test methods are compared. Results indicate the infrared simulation is an effective solar panel thermal testing method.

12 CFR 252.133 - Applicability.

Code of Federal Regulations, 2014 CFR

2014-01-01

... (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Supervisory Stress Test Requirements for Covered... requirements of this subpart beginning with the stress test cycle that commences on October 1, 2013, unless... stress test cycle that commences on November 15, 2012, unless that time is extended by the Board in...

12 CFR 252.143 - Applicability.

Code of Federal Regulations, 2014 CFR

2014-01-01

... (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test Requirements for Covered... requirements of this subpart beginning with the stress test cycle commencing on October 1, 2013, unless that... stress test cycle commencing on November 15, 2012, unless that time is extended by the Board in writing...

12 CFR 252.133 - Applicability.

Code of Federal Regulations, 2013 CFR

2013-01-01

... (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Supervisory Stress Test Requirements for Covered... requirements of this subpart beginning with the stress test cycle that commences on October 1, 2013, unless... stress test cycle that commences on November 15, 2012, unless that time is extended by the Board in...

12 CFR 252.143 - Applicability.

Code of Federal Regulations, 2013 CFR

2013-01-01

... (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test Requirements for Covered... requirements of this subpart beginning with the stress test cycle commencing on October 1, 2013, unless that... stress test cycle commencing on November 15, 2012, unless that time is extended by the Board in writing...

An extended life and performance test of a low-power arcjet

NASA Technical Reports Server (NTRS)

Curran, Francis M.; Haag, Thomas W.

1988-01-01

An automated, cyclic life test was performed to demonstrate the reliability and endurance of a low power dc cycle arcjet thruster. Over 1000 hr and 500 on-off cycles were accumulated which would represent the requirements for about 15 years of on-orbit lifetime. A hydrogen/nitrogen propellant mixture was used to simulate decomposed hydrazine propellant and the power level was nominally 1.2 kW after the burn-in period. The arcjet operated in a very repeatable fashion from cycle to cycle. The steady state voltage increased by approximately 6 V over the first 300 hr, and then by only 3 V through the remainder of the test. Thrust measurements taken before, during, and after the test verified that the thruster performed in a consistent fashion throughout the tests at a specific impulse of 450 to 460 sec. Post-test component evaluation revealed limited erosion on both the anode and cathode. Other thruster components, including graphite seals, appeared undamaged.

Investigation of thermal fatigue in fiber composite materials. [(thermal cycling tests)

NASA Technical Reports Server (NTRS)

Fahmy, A. A.; Cunningham, T. G.

1976-01-01

Graphite-epoxy laminates were thermally cycled to determine the effects of thermal cycles on tensile properties and thermal expansion coefficients of the laminates. Three 12-ply laminate configurations were subjected to up to 5,000 thermal cycles. The cumulative effect of the thermal cycles was determined by destructive inspection (electron micrographs and tensile tests) of samples after progressively larger numbers of cycles. After thermal cycling, the materials' tensile strengths, moduli, and thermal expansion coefficients were significantly lower than for the materials as fabricated. Most of the degradation of properties occurred after only a few cycles. The property degradation was attributed primarily to the progressive development of matrix cracks whose locations depended upon the layup orientation of the laminate.

Monitoring of freeze-thaw cycles in concrete using embedded sensors and ultrasonic imaging.

PubMed

Ranz, Javier; Aparicio, Sofía; Romero, Héctor; Casati, María Jesús; Molero, Miguel; González, Margarita

2014-01-29

This paper deals with the study of damage produced during freeze-thaw (F-T) cycles using two non-destructive measurement approaches-the first approach devoted to continuous monitoring using embedded sensors during the cycles, and the second one, performing ultrasonic imaging before and after the cycles. Both methodologies have been tested in two different types of concrete specimens, with and without air-entraining agents. Using the first measurement approach, the size and distribution of pores were estimated using a thermoporometrical model and continuous measurements of temperature and ultrasonic velocity along cycles. These estimates have been compared with the results obtained using mercury porosimetry testing. In the second approach, the damage due to F-T cycles has been evaluated by automated ultrasonic transmission and pulse-echo inspections made before and after the cycles. With these inspections the variations in the dimensions, velocity and attenuation caused by the accelerated F-T cycles were determined.

Monitoring of Freeze-Thaw Cycles in Concrete Using Embedded Sensors and Ultrasonic Imaging

PubMed Central

Ranz, Javier; Aparicio, Sofía; Romero, Héctor; Casati, María Jesús; Molero, Miguel; González, Margarita

2014-01-01

This paper deals with the study of damage produced during freeze-thaw (F-T) cycles using two non-destructive measurement approaches—the first approach devoted to continuous monitoring using embedded sensors during the cycles, and the second one, performing ultrasonic imaging before and after the cycles. Both methodologies have been tested in two different types of concrete specimens, with and without air-entraining agents. Using the first measurement approach, the size and distribution of pores were estimated using a thermoporometrical model and continuous measurements of temperature and ultrasonic velocity along cycles. These estimates have been compared with the results obtained using mercury porosimetry testing. In the second approach, the damage due to F-T cycles has been evaluated by automated ultrasonic transmission and pulse-echo inspections made before and after the cycles. With these inspections the variations in the dimensions, velocity and attenuation caused by the accelerated F-T cycles were determined. PMID:24481231

40 CFR 86.1333-2010 - Transient test cycle generation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Transient test cycle generation. 86... (CONTINUED) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1333-2010 Transient test cycle generation. (a) Generating transient test...

40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

Code of Federal Regulations, 2013 CFR

2013-07-01

... model year, measure emissions by testing the engine on a dynamometer with the duty cycle described in Appendix II to determine whether it meets the transient emission standards in § 1048.101(a). (b) Calculate cycle statistics and compare with the established criteria as specified in 40 CFR 1065.514 to confirm...

40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

Code of Federal Regulations, 2011 CFR

2011-07-01

... model year, measure emissions by testing the engine on a dynamometer with the duty cycle described in Appendix II to determine whether it meets the transient emission standards in § 1048.101(a). (b) Calculate cycle statistics and compare with the established criteria as specified in 40 CFR 1065.514 to confirm...

40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

Code of Federal Regulations, 2014 CFR

2014-07-01

... model year, measure emissions by testing the engine on a dynamometer with the duty cycle described in Appendix II to determine whether it meets the transient emission standards in § 1048.101(a). (b) Calculate cycle statistics and compare with the established criteria as specified in 40 CFR 1065.514 to confirm...

40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

Code of Federal Regulations, 2012 CFR

2012-07-01

... model year, measure emissions by testing the engine on a dynamometer with the duty cycle described in Appendix II to determine whether it meets the transient emission standards in § 1048.101(a). (b) Calculate cycle statistics and compare with the established criteria as specified in 40 CFR 1065.514 to confirm...

EOS-AM1 Nickel Hydrogen Cell Interim Life Test Report

NASA Technical Reports Server (NTRS)

Bennett, C. W.; Keys, D. J.; Rao, G. M.; Wannemacher, H. E.; Vaidyanathan, H.

1997-01-01

This paper reports the interim results of the Earth Observing System AM-1 project (EOS-AM-1) nickel hydrogen cell life test being conducted under contract to National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) at the Lockheed Martin Missiles and Space (LMMS) facility in East Windsor, NJ; and at COMSAT Labs., Clarksburg, MD. The purpose of the tests is to verify that the EOS-AM-l cell design can meet five years of real-time Low Earth Orbit (LEO) cycling. The tests include both real-time LEO and accelerated stress tests. At LMMS, the first real-time LEO simulated 99 minute orbital cycle started on February 7, 1994 and the test has been running continuously since that time, with 13000 LEO cycles completed as of September 2, 1996. Each cycle consists of a 64 minute charge (VT at 1.507 volts per cell, 1.06 C/D ratio, followed by 0.6 ampere trickle charge) and a 35 minute constant power discharge at 177 watts (22.5% DOD). At COMSAT, the accelerated stress test consists of 90 minute orbital cycles at 60% DOD with a 30 minute discharge at 60 amperes and a 60 minute charge at 40 ampercs (VT at 1.54 volts per cell to 1.09 C/D ratio, followed by 0.6 ampere trickle charge). The real-time LEO life test battery consists of seven, 50AH (nameplate rating) Eagle-Picher, Inc. (EPI) Mantech cells manufactured into three, 3-cell pack assemblies (there are two place holder cells that are not part of the life test electrical circuit). The test pack is configured to simulate the conductive thermal design of the spacecraft battely, including: conductive aluminum sleeves, 3-cell pack aluminum baseplate, and honeycomb panel all mounted to a liquid (-5 C) cold plate. The entire assembly is located in a thermal chamber operating at +3 C. The accelerated stress test unit consists of five cells mounted in machined aluminum test sleeves and is operating at +10 C. The real-time LEO life test battery has met all performance requirements through the first 13,000 cycles, including: end of charge and discharge cell voltages and voltage gradients; end of chalge and discharge cell pressures; within cell and between cell temperature gradients; discharge capacity; current and power levels; and all chalge parameters. The accelerated stress test battely has completed over 5900 cycles as of 9/11/96. This paper reports both battery performances as a function of cycle life, with individual cell performance comparisons repolted for selected cycles in both tests.

12 CFR 252.153 - Applicability.

Code of Federal Regulations, 2014 CFR

2014-01-01

... (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test Requirements for Banking... December 31, 2012, must comply with the requirements of this subpart beginning with the stress test cycle... the stress test cycle that commences on October 1, 2015, unless that time is extended by the Board in...

Number size distribution of particulate emissions of heavy-duty engines in real world test cycles

NASA Astrophysics Data System (ADS)

Lehmann, Urs; Mohr, Martin; Schweizer, Thomas; Rütter, Josef

Five in-service engines in heavy-duty trucks complying with Euro II emission standards were measured on a dynamic engine test bench at EMPA. The particulate matter (PM) emissions of these engines were investigated by number and mass measurements. The mass of the total PM was evaluated using the standard gravimetric measurement method, the total number concentration and the number size distribution were measured by a Condensation Particle Counter (lower particle size cut-off: 7 nm) and an Electrical Low Pressure Impactor (lower particle size: 32 nm), respectively. The transient test cycles used represent either driving behaviour on the road (real-world test cycles) or a type approval procedure. They are characterised by the cycle power, the average cycle power and by a parameter for the cycle dynamics. In addition, the particle number size distribution was determined at two steady-state operating modes of the engine using a Scanning Mobility Particle Sizer. For quality control, each measurement was repeated at least three times under controlled conditions. It was found that the number size distributions as well as the total number concentration of emitted particles could be measured with a good repeatability. Total number concentration was between 9×10 11 and 1×10 13 particles/s (3×10 13-7×10 14 p/kWh) and mass concentration was between 0.09 and 0.48 g/kWh. For all transient cycles, the number mean diameter of the distributions lay typically at about 120 nm for aerodynamic particle diameter and did not vary significantly. In general, the various particle measurement devices used reveal the same trends in particle emissions. We looked at the correlation between specific gravimetric mass emission (PM) and total particle number concentration. The correlation tends to be influenced more by the different engines than by the test cycles.

Cycling induced by electrical stimulation improves motor recovery in postacute hemiparetic patients: a randomized controlled trial.

PubMed

Ambrosini, Emilia; Ferrante, Simona; Pedrocchi, Alessandra; Ferrigno, Giancarlo; Molteni, Franco

2011-04-01

This study assessed whether cycling induced by functional electrical stimulation (FES) was more effective than passive cycling with placebo stimulation in promoting motor recovery and walking ability in postacute hemiparetic patients. In a double-blind, randomized, controlled trial, 35 patients were included and randomized to receive FES-induced cycling training or placebo FES cycling. The 4-week treatment consisted of 20 sessions lasting 25 minutes each. Primary outcome measures included the leg subscale of the Motricity Index and gait speed during a 50-meter walking test. Secondary outcomes were the Trunk Control Test, the Upright Motor Control Test, the mean work produced by the paretic leg, and the unbalance in mechanical work between paretic and nonparetic legs during voluntary pedaling. Participants were evaluated before training, after training, and at 3- to 5-month follow-up visits. No significant differences were found between groups at baseline. Repeated-measures ANOVA (P<0.05) revealed significant increases in Motricity Index, Trunk Control Test, Upright Motor Control Test, gait speed, and mean work of the paretic leg after training and at follow-up assessments for FES-treated patients. No outcome measures demonstrated significant improvements after training in the placebo group. Both groups showed no significant differences between assessments after training and at follow-up. A main effect favoring FES-treated patients was demonstrated by repeated-measures ANCOVA for Motricity Index (P<0.001), Trunk Control Test (P=0.001), Upright Motor Control Test (P=0.005), and pedaling unbalance (P=0.038). The study demonstrated that 20 sessions of FES cycling training significantly improved lower extremity motor functions and accelerated the recovery of overground locomotion in postacute hemiparetic patients. Improvements were maintained at follow-up.

MHD program plan, FY 1991

NASA Astrophysics Data System (ADS)

1990-10-01

The current magnetohydrodynamic MHD program being implemented is a result of a consensus established in public meetings held by the Department of Energy in 1984. The public meetings were followed by the formulation of a June 1984 Coal-Fired MHD Preliminary Transition and Program Plan. This plan focused on demonstrating the proof-of-concept (POC) of coal-fired MHD electric power plants by the early 1990s. MHD test data indicate that while there are no fundamental technical barriers impeding the development of MHD power plants, technical risk remains. To reduce the technical risk three key subsystems (topping cycle, bottoming cycle, and seed regeneration) are being assembled and tested separately. The program does not require fabrication of a complete superconducting magnet, but rather the development and testing of superconductor cables. The topping cycle system test objectives can be achieved using a conventional iron core magnet system already in place at a DOE facility. Systems engineering-derived requirements and analytical modeling to support scale-up and component design guide the program. In response to environmental, economic, engineering, and utility acceptance requirements, design choices and operating modes are tested and refined to provide technical specifications for meeting commercial criteria. These engineering activities are supported by comprehensive and continuing systems analyses to establish realistic technical requirements and cost data. Essential elements of the current program are to: develop technical and environmental data for the integrated MHD topping cycle and bottoming cycle systems through POC testing (1000 and 4000 hours, respectively); design, construct, and operate a POC seed regeneration system capable of processing spent seed materials from the MHD bottoming cycle; prepare conceptual designs for a site specific MHD retrofit plant; and continue supporting research necessary for system testing.

12 CFR 252.145 - Mid-cycle stress test.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 12 Banks and Banking 4 2013-01-01 2013-01-01 false Mid-cycle stress test. 252.145 Section 252.145... (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test Requirements for Covered Companies § 252.145 Mid-cycle stress test. (a) Mid-cycle stress test requirement. In addition to the stress...

12 CFR 252.145 - Mid-cycle stress test.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 12 Banks and Banking 4 2014-01-01 2014-01-01 false Mid-cycle stress test. 252.145 Section 252.145... (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test Requirements for Covered Companies § 252.145 Mid-cycle stress test. (a) Mid-cycle stress test requirement. In addition to the stress...

40 CFR 89.410 - Engine test cycle.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine test cycle. 89.410 Section 89...) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Exhaust Emission Test Procedures § 89.410 Engine test cycle. (a) Emissions shall be measured using one of the test cycles specified...

40 CFR 89.410 - Engine test cycle.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Engine test cycle. 89.410 Section 89...) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Exhaust Emission Test Procedures § 89.410 Engine test cycle. (a) Emissions shall be measured using one of the test cycles specified...

40 CFR 89.410 - Engine test cycle.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine test cycle. 89.410 Section 89...) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Exhaust Emission Test Procedures § 89.410 Engine test cycle. (a) Emissions shall be measured using one of the test cycles specified...

Effect of HIP temperature on microstructure and low cycle fatigue strength of CuCrZr alloy

NASA Astrophysics Data System (ADS)

Nishi, Hiroshi; Enoeda, Mikio

2011-10-01

In order to investigate the effect of the HIP cycle temperatures on the metallurgic degradation and the mechanical properties of CuCrZr alloy, assessments of the microstructure, tensile test, Charpy impact test and low cycle fatigue test are performed for various heat treated CuCrZr alloys, which were solution-annealed followed by water-quenched and aged state of CuCrZr with simulated HIP cycle at temperatures of 980 and 1045 °C. Grain growth occurred on 1045 °C HIP CuCrZr, though slightly on 980 °C HIP CuCrZr. Metallurgic degradation such as voids was not found by optical and SEM observations. There were coarse precipitates in all the CuCrZr and the precipitates did not easily dissolve at 980 °C. The low cycle fatigue strength of 1045 °C HIP CuCrZr was lower than that of other CuCrZr because of the metallurgic degradation caused by the heat cycle, while that of other CuCrZr was corresponding to the best fit curve of ITER MPH.

Development and testing of a high cycle life 30 A-h sealed AgO-Zn battery

NASA Technical Reports Server (NTRS)

Bogner, R. S.

1972-01-01

A two-phase program was initiated to investigate design parameters and technology to develop an improved AgO-Zn battery. The basic performance goal was 100 charge/discharge cycles (22 h/2 h) at 50 percent depth of discharge following a six-month period of charged stand at room temperature. Phase 1, cell evaluation, involved testing 70 cells in five-cell groups. The major design variables were active material ratios, electrolyte concentrations, separator systems, and negative plate shape. Phase 1 testing showed that cycle life could be improved 10 percent to 20 percent by using greater ratios of zinc to silver oxide and higher electrolyte concentrations. Wedge-shaped negatives increased cycle life by nearly 100 percent. Phase 2 battery evaluation, which was initiated before the Phase 1 results were known completely, involved evaluation of six designs as 19-cell batteries. Only one battery exceeded 100 cycles following nine months charged stand.

Micro-fractures produced in the Cadalso de los Vidrios granite (Madrid) subjected to Freeze-Thaw Durability Testing

NASA Astrophysics Data System (ADS)

Freire-Lista, D. M.; Varas-Muriel, M. J.; Fort, R.

2012-04-01

A specific leucogranite (fine to medium grain sized) from Cadalso de los Vidrios, Madrid, Spain, from where it takes the name of the stone variety, which is a traditional heritage building material used in Central Spain, was subjected to freezing-thaw durability tests or accelerated artificial ageing tests (according to Spanish standard EN 12371:2001) to assess its durability by means of ultrasonic velocity measurements (a non-destructive technique), and optical and fluorescence petrography using a polarized optical microscope (destructive technique), both techniques used before, during and after laboratory ageing tests, or in other words, what is determined is the improvement or deterioration in some properties. The measurement of the ultrasonic velocity in the leucogranite cubic test specimens along the freezing-thaw cycles shown that the velocity diminishes with the number of cycles, in relation to the decay that the stones were experiencing. This deterioration can be observed by the loss of crystalline minerals in the surface of the analyzed samples and by the micro-fractures appearance up to one centimeter deep, which have been detected by the petrographic techniques previously mentioned. The images taken by means of the fluorescence microscope clearly show the micro-fractures generated during the durability test. These images have been processed and analyzed by the UTHSCSA Image Tool program with the purpose of being able to quantify the degree of decay that this type of crystalline materials undergone, when subjected to a number of freezing-thaw test cycles. It is therefore an effective, reliable and complementary technique to that of the petrography analysis, both optical and fluorescence ones. In the first cycles of the ageing test, the micro-fractures propagate along crystals edges and during the last cycles of the test, intracrystalline micro-fractures are generated, which are developed in different ways depending on the mineralogy of the crystals. Thus, the quartz crystals are those that undergo more intracrystalline micro-fractures, whereas the biotites, behave in a more ductile form and they are not micro-fractured. Both analytical techniques give information of this granite deterioration, showing a relation between the number of freezing-thaw cycles, the superficial micro-fractures proliferation and the decrease of ultrasonic waves propagation velocity produced by the ageing cycles.

Influence of driving cycles on exhaust emissions and fuel consumption of gasoline passenger car in Bangkok.

PubMed

Nutramon, Tamsanya; Supachart, Chungpaibulpatana

2009-01-01

The influence of different driving cycles on their exhaust emissions and fuel consumption rate of gasoline passenger car was investigated in Bangkok based on the actual measurements obtained from a test vehicle driving on a standard chassis dynamometer. A newly established Bangkok driving cycle (BDC) and the European driving cycle (EDC) which is presently adopted as the legislative cycle for testing automobiles registered in Thailand were used. The newly developed BDC is constructed using the driving characteristic data obtained from the real on-road driving tests along selected traffic routes. A method for selecting appropriate road routes for real driving tests is also introduced. Variations of keyed driving parameters of BDC with different driving cycles were discussed. The results showed that the HC and CO emission factors of BDC are almost two and four times greater than those of EDC, respectively. Although the difference in the NOx emission factor is small, the value from BDC is still greater than that of EDC by 10%. Under BDC, the test vehicle consumes fuel about 25% more than it does under EDC. All these differences are mainly attributed to the greater proportion of idle periods and higher fluctuations of vehicle speed in the BDC cycle. This result indicated that the exhausted emissions and fuel consumption of vehicles obtained from tests under the legislative modal-type driving cycle (EDC) are significantly different from those actually produced under real traffic conditions especially during peak periods.

40 CFR 1039.505 - How do I test engines using steady-state duty cycles, including ramped-modal testing?

Code of Federal Regulations, 2010 CFR

2010-07-01

...-state duty cycles, including ramped-modal testing? 1039.505 Section 1039.505 Protection of Environment... duty cycles, including ramped-modal testing? This section describes how to test engines under steady-state conditions. In some cases, we allow you to choose the appropriate steady-state duty cycle for an...

40 CFR 90.410 - Engine test cycle.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine test cycle. 90.410 Section 90...) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Gaseous Exhaust Test Procedures § 90.410 Engine test cycle. (a) Follow the appropriate 6-mode test cycle for Class I, I-B and II...

40 CFR 90.410 - Engine test cycle.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine test cycle. 90.410 Section 90...) CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS Gaseous Exhaust Test Procedures § 90.410 Engine test cycle. (a) Follow the appropriate 6-mode test cycle for Class I, I-B and II...

Influence of the loading frequency on the wear rate of a polyethylene-on-metal lumbar intervertebral disc replacement.

PubMed

Kettler, Annette; Bushelow, Michael; Wilke, Hans-Joachim

2012-06-01

Pre-clinical wear testing of intervertebral disc prostheses is commonly carried out according to ISO 18192-1. Ten million multiaxial loading cycles are applied at a frequency of 1 Hz. At this frequency, testing takes about 4 months. Testing at higher frequencies would therefore be desirable. ISO 18192-1 also offers testing at 2 Hz; however, it says the impact on the implant material behaviour as well as on the accuracy of the test machine shall be investigated by the user. Since such data are not available so far, the aim of this study was to carry out comparative wear tests at 1 and 2 Hz. Seven Prodisc-L lumbar disc prostheses were tested. After a pre-soak period, the implants were placed in specimen cups filled with calf serum, mounted to a Spine Wear Simulator and loaded according to ISO 18192-1. Testing was carried out at a temperature of 37 ± 2 °C. Four million loading cycles were applied at 1 Hz and eight million at 2 Hz in an alternating sequence. Each time after 12 days of testing the implants were removed to measure the weight and the height of the polyethylene cores. Then, the test serum was exchanged and the implants were remounted to the testing machine. The mean wear rate was 5.6 ± 2.3 mg per million cycles at 1 Hz and 7.7 ± 1.6 mg per million cycles at 2 Hz during the first six million loading cycles (p < 0.05) and 2.0 ± 0.6 and 4.1 ± 0.7 mg per million cycles during the second six million cycles (p < 0.05). Similarly, the mean heightloss was also smaller at 1 Hz than at 2 Hz (p < 0.05) with -0.02 ± 0.02 mm versus -0.04 ± 0.02 mm per million cycles during the first half of testing and -0.01 ± 0.01 versus -0.02 ± 0.01 mm per million cycles during the second half. The accuracy of the test machine was within the limits described by ISO 18192-1 at both frequencies. The results showed that the wear rate was higher at the beginning than at the end of testing. Also, the results indicated that testing at 2 Hz increases the wear rate compared with 1 Hz in case of a polyethylene-on-metal implant design. In the absence of retrieval studies it is difficult to decide which rate results in a more physiological wear pattern. However, a loading frequency of 1 Hz is probably closer to physiology than 2 Hz since the loading amplitudes prescribed by ISO 18192-1 are high. They rather represent movements like tying shoes or standing up from a chair than walking or sitting. The authors therefore suggest testing at 1 Hz.

Nickel hydrogen cell tests. [recharging

NASA Technical Reports Server (NTRS)

Mueller, V. C.

1981-01-01

Some parametric tests followed by cycling tests are described for the characterization of the service life of nickel hydrogen cells. Three cells were automatically cycled in simulated low Earth orbit in 35 minute discharge, 55 minute charge, with charging voltage limited, temperature compensated. The cells were mounted in a fixture that conducts heat to an aluminum baseplate. The baseplate in turn, is bounded in a temperature controlled bath to remove the heat from the mounted fixture. One cell was tested with a zircar separator, which failed after 2473 cyles. Two other cells were tested one with a zircar separator; the other with asbestos. More than 400 cycles were achieved.

40 CFR 86.1341-98 - Test cycle validation criteria.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Test cycle validation criteria. 86...) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1341-98 Test cycle validation criteria. Section 86.1341-98 includes text that specifies...

Analysis of ProSEDS Test of Bare-Tether Collection

NASA Technical Reports Server (NTRS)

Sanmartin, J. R.; Lorenzini, E. C.; Estes, R. D.; Charro, M.; Cosmo, M. L.

2003-01-01

NASA's tether experiment ProSEDS will be placed in orbit on board a Delta-II rocket to test bare-tether electron collection, deorbiting of the rocket second stage, and the system dynamic stability. ProSEDS performance will vary because ambient conditions change along the orbit and tether-circuit bulk elements at the cathodic end follow the step-by-step sequence for the current cycles of operating modes (open-circuit, shunt and resistor modes for primary cycles; shunt and battery modes for secondary cycles). In this work we discuss expected ProSEDS values of the ratio L,/L*, which jointly with cathodic bulk elements determines bias and current tether profiles; L, is tether length, and L* (changing with tether temperature and ionospheric plasma density and magnetic field) is a characteristic length gauging ohmic versus baretether collection impedances. We discuss how to test bare-tether electron collection during primary cycles, using probe measurements of plasma density, measurements of cathodic current in resistor and shunt modes, and an estimate of tether temperature based on ProSEDS orbital position at the particular cycle concerned. We discuss how a temperature misestimate might occasionally affect the test of bare-tether collection, and how introducing the battery mode in some primary cycles, for an additional current measurement, could obviate the need of a temperature estimate. We also show how to test bare-tether collection by estimating orbit-decay rate from measurements of cathodic current for the shunt and battery modes of secondary cycles.

Single-Cycle Versus Multicycle Proof Testing

NASA Technical Reports Server (NTRS)

Hudak, S. J., Jr.; Mcclung, R. C.; Bartlett, M. L.; Fitzgerald, J. H.; Russell, D. A.

1992-01-01

Report compares single-cycle with multiple-cycle mechanical-stress tests of parts under mechanical stresses. Objective of proof testing: to screen out gross manufacturing or material deficiencies and provide additional assurance of quality. Report concludes that changes in distribution of crack sizes during multicycle proof testing depend on initial distribution, number of cycles, relationship between resistance of material and elastic/plastic fracture-mechanics parameter, relationship between load control and displacement control, and magnitude of applied load or displacement. Whether single-cycle or multicycle testing used depends on shape, material, and technique of fabrication of components tested.

Correlation between the median particle size of chewed frankfurter sausage and almonds during masticatory performance test.

PubMed

Sumonsiri, P; Thongudomporn, U; Paphangkorakit, J

2018-04-27

The correlation between chewing and gastric function is best reflected when the same food type is used during both tests. We proposed frankfurter sausage as test food for masticatory performance as it can also be used in gastric emptying test. The suitability of frankfurter sausage to determine masticatory performance, however, has never been examined. To examine the correlations between the median particle size of frankfurter sausage and almonds (as standard test food) after different numbers of chewing cycles. Twenty-seven subjects performed masticatory performance tests by chewing 2 types of test foods, that is, a piece of almond or 5-g frankfurter sausage cubes placed in a sealed latex bag, for 5 and 15 chewing cycles. For each individual, right and left sides were tested separately. Chewed samples obtained from both sides were pooled. Median particle sizes were determined using a multiple sieving method. Spearman's rank correlation was used to examine any correlation between median particle sizes of the 2 test foods after 5 and 15 cycles. Median particle sizes after 5 and 15 cycles were 2.04 ± 0.87 and 0.95 ± 0.58 mm for almonds and 4.16 ± 0.19 and 3.73 ± 0.25 mm for frankfurter sausage, respectively. Significant correlations were observed between the median particle size of chewed frankfurter sausage after 15 cycles and that of chewed almonds after 5 and 15 cycles (r = .76, P < .01 and r = .52, P = .01, respectively). Frankfurter sausage chewed for 15 cycles may be suitable for the determination of masticatory performance in conjunction with gastric emptying test. © 2018 John Wiley & Sons Ltd.

The Measurement of Maximal (Anaerobic) Power Output on a Cycle Ergometer: A Critical Review

PubMed Central

Driss, Tarak; Vandewalle, Henry

2013-01-01

The interests and limits of the different methods and protocols of maximal (anaerobic) power (P max) assessment are reviewed: single all-out tests versus force-velocity tests, isokinetic ergometers versus friction-loaded ergometers, measure of P max during the acceleration phase or at peak velocity. The effects of training, athletic practice, diet and pharmacological substances upon the production of maximal mechanical power are not discussed in this review mainly focused on the technical (ergometer, crank length, toe clips), methodological (protocols) and biological factors (muscle volume, muscle fiber type, age, gender, growth, temperature, chronobiology and fatigue) limiting P max in cycling. Although the validity of the Wingate test is questionable, a large part of the review is dedicated to this test which is currently the all-out cycling test the most often used. The biomechanical characteristics specific of maximal and high speed cycling, the bioenergetics of the all-out cycling exercises and the influence of biochemical factors (acidosis and alkalosis, phosphate ions…) are recalled at the beginning of the paper. The basic knowledge concerning the consequences of the force-velocity relationship upon power output, the biomechanics of sub-maximal cycling exercises and the study on the force-velocity relationship in cycling by Dickinson in 1928 are presented in Appendices. PMID:24073413

Influence of Thermal Cycles Number on Bond Strength of Metallic Brackets to Ceramic.

PubMed

Jurubeba, José Eliú Pereira; Costa, Ana Rosa; Correr-Sobrinho, Lourenço; Tubel, Carlos Alberto Malanconi; Correr, Américo Bortolazzo; Vedovello, Silvia Amélia; Crepaldi, Marcus Vinicius; Vedovello, Mário

2017-01-01

The aim of this study was to evaluate the effect of different number of thermal cycles on the shear bond strength (SBS) of metallic orthodontic brackets bonded to feldspathic ceramic by a composite resin. Twenty-five ceramic cylinders were etched with 10% hydrofluoric acid for 60 s and received two layers of silane. Brackets were bonded to the cylinders using Transbond XT and assigned to 5 groups (n=5): Group 1 - Control group (without thermal cycling); Group 2 - 500 thermal cycles; Group 3 - 5,000 thermal cycles; Group 4 - 7,000 thermal cycles and Group 5 - 10,000 thermal cycles. Light-activation was carried out by Radii Plus LED. SBS testing was carried out after 24 h of storage in deionized water and thermal cycling (5/55 oC and 30 s dwell time). Five brackets were bonded to each cylinder, totalizing 25 brackets for each group. Data were submitted to one-way ANOVA and Tukey's test (α=0.05). The Adhesive Remnant Index (ARI) was evaluated at 8× magnification. The SBS (MPa) of control group (9.3±0.8), 500 (9.0±0.7) and 5,000 (8.4±0.9) thermal cycles were significantly higher than those after 7,000 (6.8±0.6) and 10,000 (4.9±1.0) thermal cycles (p<0.05). The ARI showed a predominance of Scores 0 (adhesive failure) prevailed in all groups, as shown by the ARI, with increased scores 1 and 2 (mixed failures) for control group and 500 thermal cycles. In conclusion, thermal fatigue may compromise the bonding integration between metallic brackets and ceramic restorations. For in vitro testing, use of at least 7,000 cycles is advised to result in significant fatigue on the bonding interface.

40 CFR 600.207-08 - Calculation and use of vehicle-specific 5-cycle-based fuel economy values for vehicle...

Code of Federal Regulations, 2011 CFR

2011-07-01

.... (i) Calculate the 5-cycle city and highway fuel economy values from the tests performed using gasoline or diesel test fuel. (ii)(A) Calculate the 5-cycle city and highway fuel economy values from the tests performed using alcohol or natural gas test fuel, if 5-cycle testing has been performed. Otherwise...

40 CFR 1048.505 - How do I test engines using steady-state duty cycles, including ramped-modal testing?

Code of Federal Regulations, 2010 CFR

2010-07-01

...-state duty cycles, including ramped-modal testing? 1048.505 Section 1048.505 Protection of Environment... SPARK-IGNITION ENGINES Test Procedures § 1048.505 How do I test engines using steady-state duty cycles... some cases, we allow you to choose the appropriate steady-state duty cycle for an engine. In these...

Drive Cycle Analysis Tool - DriveCAT | NREL

Science.gov Websites

tool was created by NREL's fleet test and evaluation team, which conducts in-service performance their needs. Learn more about NREL's fleet test and evaluation research. Contact Us Let us know if you have any questions about the data, need assistance, or would like to contribute test cycles. We also

40 CFR 86.336-79 - Diesel engine test cycle.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Diesel engine test cycle. 86.336-79... New Gasoline-Fueled and Diesel-Fueled Heavy-Duty Engines; Gaseous Exhaust Test Procedures § 86.336-79 Diesel engine test cycle. (a) The following 13-mode cycle shall be followed in dynamometer operation...

40 CFR 86.335-79 - Gasoline-fueled engine test cycle.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Gasoline-fueled engine test cycle. 86....335-79 Gasoline-fueled engine test cycle. (a) The following test sequence shall be followed in.... Cycle No. Mode No. Mode Observed torque (percent of maximum observed) Time in mode-seconds Cumulative...

40 CFR 86.1341-90 - Test cycle validation criteria.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Test cycle validation criteria. 86...) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1341-90 Test cycle validation criteria. (a) To minimize the biasing effect of the time lag...

Investigation of Low-Cycle Bending Fatigue of AISI 9310 Steel Spur Gears

NASA Technical Reports Server (NTRS)

Handschuh, Robert F.; Krantz, Timothy L.; Lerch, Bradley A.; Burke, Christopher S.

2007-01-01

An investigation of the low-cycle bending fatigue of spur gears made from AISI 9310 gear steel was completed. Tests were conducted using the single-tooth bending method to achieve crack initiation and propagation. Tests were conducted on spur gears in a fatigue test machine using a dedicated gear test fixture. Test loads were applied at the highest point of single tooth contact. Gear bending stresses for a given testing load were calculated using a linear-elastic finite element model. Test data were accumulated from 1/4 cycle to several thousand cycles depending on the test stress level. The relationship of stress and cycles for crack initiation was found to be semi-logarithmic. The relationship of stress and cycles for crack propagation was found to be linear. For the range of loads investigated, the crack propagation phase is related to the level of load being applied. Very high loads have comparable crack initiation and propagation times whereas lower loads can have a much smaller number of cycles for crack propagation cycles as compared to crack initiation.

Investigation of Low-Cycle Bending Fatigue of AISI 9310 Steel Spur Gears

NASA Technical Reports Server (NTRS)

Handschuh, Robert F.; Krantz, Timothy L.; Lerch, Bradley A.; Burke, Christopher S.

2007-01-01

An investigation of the low-cycle bending fatigue of spur gears made from AISI 9310 gear steel was completed. Tests were conducted using the single-tooth bending method to achieve crack initiation and propagation. Tests were conducted on spur gears in a fatigue test machine using a dedicated gear test fixture. Test loads were applied at the highest point of single tooth contact. Gear bending stresses for a given testing load were calculated using a linear-elastic finite element model. Test data were accumulated from 1/4 cycle to several thousand cycles depending on the test stress level. The relationship of stress and cycles for crack initiation was found to be semilogarithmic. The relationship of stress and cycles for crack propagation was found to be linear. For the range of loads investigated, the crack propagation phase is related to the level of load being applied. Very high loads have comparable crack initiation and propagation times whereas lower loads can have a much smaller number of cycles for crack propagation cycles as compared to crack initiation.

NASA welding assessment program

NASA Technical Reports Server (NTRS)

Stofel, E. J.

1984-01-01

A long duration test was conducted for comparing various methods of attaching electrical interconnects to solar cells for near Earth orbit spacecraft. Representative solar array modules were thermally cycled for 36,000 cycles between -80 and +80 C. The environmental stress of more than 6 years on a near Earth spacecraft as it cycles in and out of the earth's shadow was simulated. Evaluations of the integrity of these modules were made by visual and by electrical examinations before starting the cycling and then at periodic intervals during the cycling tests. Modules included examples of parallel gap and of ultrasonic welding, as well as soldering. The materials and fabrication processes are state of the art, suitable for forming large solar arrays of spacecraft quality. The modules survived this extensive cycling without detectable degradation in their ability to generate power under sunlight illumination.

Effect of components and surface treatments of fiber-reinforced composite posts on bond strength to composite resin.

PubMed

Asakawa, Yuya; Takahashi, Hidekazu; Kobayashi, Masahiro; Iwasaki, Naohiko

2013-10-01

The aim of this study was to clarify the effect of the components and surface treatments of fiber-reinforced composite (FRC) posts on the durable bonding to core build-up resin evaluated using the pull-out and microtensile tests. Four types of experimental FRC posts, combinations of two types of matrix resins (polymethyl methacrylate and urethane dimethacrylate) and two types of fiberglass (E-glass and zirconia-containing glass) were examined. The FRC posts were subjected to one of three surface treatments (cleaned with ethanol, dichloromethane, or sandblasting). The bond strength between the FRC posts and core build-up resin were measured using the pull-out and microtensile tests before and after thermal cycling. The bond strengths obtained by each test before and after thermal cycling were statistically analyzed by three-way ANOVA and Tukey's multiple comparisons test (p<0.05). The bond strengths except for UDMA by the pull-out test decreased after thermal cycling. Regardless the test method and thermal cycling, matrix resins, the surface treatment and their interaction were statistically significant, but fiberglass did not. Dichloromethane treatment was effective for the PMMA-based FRC posts by the pull-out test, but not by the microtensile test. Sandblasting was effective for both PMMA- and UDMA-based FRC posts, regardless of the test method. The bond strengths were influenced by the matrix resin of the FRC post and the surface treatment. The bond strengths of the pull-out test showed a similar tendency of those of the microtensile test, but the value obtained by these test were different. Copyright © 2013 Elsevier Ltd. All rights reserved.

JT9D ceramic outer air seal system refinement program

NASA Technical Reports Server (NTRS)

Gaffin, W. O.

1982-01-01

The abradability and durability characteristics of the plasma sprayed system were improved by refinement and optimization of the plasma spray process and the metal substrate design. The acceptability of the final seal system for engine testing was demonstrated by an extensive rig test program which included thermal shock tolerance, thermal gradient, thermal cycle, erosion, and abradability tests. An interim seal system design was also subjected to 2500 endurance test cycles in a JT9D-7 engine.

KOH concentration effect on cycle life of nickel-hydrogen cells

NASA Technical Reports Server (NTRS)

Lim, Hong S.; Verzwyvelt, S. A.

1987-01-01

A cycle life test of Ni/H2 cells containing electrolytes of various KOH concentrations and a sintered type nickel electrode was carried out at 23 C using a 45 min accelerated low Earth orbit (LEO) cycle regime at 80 percent depth of discharge. One of three cells containing 26 percent KOH has achieved over 28,000 cycles, and the other two 19,000 cycles, without a sign of failure. Two other cells containing 31 percent KOH electrolyte, which is the concentration presently used in aerospace cells, failed after 2,979 and 3,620 cycles. This result indicates that the cycle life of the present type of Ni/H2 cells may be extended by a factor of 5 to 10 simply by lowering the KOH concentration. Long cycle life of a Ni/H2 battery at high depth-of-discharge operation is desired, particularly for an LEO spacecraft application. Typically, battery life of about 30,000 cycles is required for a five year mission in an LEO. Such a cycle life with presently available cells can be assured only at a very low depth-of-discharge operation. Results of testing already show that the cycle life of an Ni/H2 cell is tremendously improved by simply using an electrolyte of low KOH concentration.

Capacity fading of LiAlyNi1-x-yCoxO2 cathode for lithium-ion batteries during accelerated calendar and cycle life tests (effect of depth of discharge in charge-discharge cycling on the suppression of the micro-crack generation of LiAlyNi1-x-yCoxO2 particle)

NASA Astrophysics Data System (ADS)

Watanabe, Shoichiro; Kinoshita, Masahiro; Hosokawa, Takashi; Morigaki, Kenichi; Nakura, Kensuke

2014-08-01

Cycle performance of a LiAl0.10Ni0.76Co0.14O2 (NCA) cathode/graphite cell closely depended on the range of depth of discharge in charge-discharge processes (ΔDOD). When ΔDOD was 10-70%, cycle performance at 25 °C was maintained even at 60 °C. Deterioration phenomena were analyzed by electrochemical method, X-ray photoelectron spectroscopy (XPS), X-ray diffractometry (XRD), and micro-cracks in NCA particles were analyzed with cross-sectional views by scanning electron microscopy (SEM). Many micro-cracks were observed only after a 0-100% DOD region cycle test. Cycle tests in several restricted ΔDOD conditions showed that the deterioration was closely related to not the upper and lower limits of DOD or operation voltage but the width of ΔDOD.

A cycle timer for testing electric vehicles

NASA Technical Reports Server (NTRS)

Soltis, R. F.

1978-01-01

A cycle timer was developed to assist the driver of an electric vehicle in more accurately following and repeating SAE driving schedules. These schedules require operating an electric vehicle in a selected stop-and-go driving cycle and repeating this cycle pattern until the vehicle ceases to meet the requirements of the cycle. The heart of the system is a programmable read-only memory (PROM) that has the required test profiles permanently recorded on plug-in cards, one card for each different driving schedule. The PROM generates a direct current analog signal that drives a speedometer displayed on one scale of a dual movement meter. The second scale of the dual movement meter displays the actual speed of the vehicle as recorded by the fifth wheel. The vehicle operator controls vehicle speed to match the desired profile speed. The PROM controls the recycle start time as well as the buzzer activation. The cycle programmer is powered by the test vehicle's 12-volt accessory battery, through a 5-volt regulator and a 12-volt dc-to-dc converter.

The evaluation of layered separators for nickel-hydrogen cells

NASA Technical Reports Server (NTRS)

Gahn, Randall F.

1991-01-01

The concept of using layered separators to achieve the required electrolyte retention and bubble pressure fo nickel-hydrogen cells was evaluated in a boilerplate cell test. Zircar cloth, polyethylene paper and polypropylene felt were combined with a layer of radiation-grafted polyethylene film to achieve the required properties. Three cells of each layered separator were built and tested by characterization cycling and by low earth orbit cycling for 5000 cycles at 80 percent DOD. Three cells containing asbestos separators were used as the reference.

Cycling Power Outputs Predict Functional Threshold Power And Maximum Oxygen Uptake.

PubMed

Denham, Joshua; Scott-Hamilton, John; Hagstrom, Amanda D; Gray, Adrian J

2017-09-11

Functional threshold power (FTP) has emerged as a correlate of lactate threshold and is commonly assessed by recreational and professional cyclists for tailored exercise programing. To identify whether results from traditional aerobic and anaerobic cycling tests could predict FTP and V˙ O2max, we analysed the association between estimated FTP, maximum oxygen uptake (V˙ O2max [mlkgmin]) and power outputs obtained from a maximal cycle ergometry cardiopulmonary exercise test (CPET) and a 30-s Wingate test in a heterogeneous cohort of cycle-trained and untrained individuals (N=40, mean±SD; age: 32.6±10.6 y; relative V˙ O2max: 46.8±9.1 mlkgmin). The accuracy and sensitivity of the prediction equations was also assessed in young men (N=11) before and after a 6-wk sprint interval training intervention.Moderate to strong positive correlations were observed between FTP, relative V˙ O2max and power outputs achieved during incremental and 30-s Wingate cycling tests (r=.39-.965, all P<.05). While maximum power achieved during incremental cycle testing (Pmax) and relative V˙ O2max were predictors of FTP (r =.93), age and FTP (Wkg) estimated relative V˙ O2max (r=.80). Our findings confirm that FTP predominantly relies on aerobic metabolism and indicate both prediction models are sensitive enough to detect meaningful exercise-induced changes in FTP and V˙ O2max. Thus, coaches should consider limiting the time and load demands placed on athletes by conducting a maximal cycle ergometry CPET to estimate FTP. Additionally, a 20-min FTP test is a convenient method to assess V˙ O2max and is particularly relevant for exercise professionals without access to expensive CPET equipment.

The use of spore strips for monitoring the sterilization of bottled fluids.

PubMed Central

Selkon, J. B.; Sisson, P. R.; Ingham, H. R.

1979-01-01

A bacterial spore test has been developed which enables the efficacy of the sterilizing cycle recommended by the British Pharmaceutical Codex (1973) for bottled fluids to be accurately monitored. During a 14-month period this test detected faults in 3.3% of the sterilizing cycles, representing five distinct episodes of sterilization failure that passed unnoticed by the conventional controls of physical measurements and sterility testing. There were no failures of sterilization as detected by conventional techniques which were not indicated by the spore test. PMID:458140

40 CFR Appendix II to Part 1054 - Duty Cycles for Laboratory Testing

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Duty Cycles for Laboratory Testing II.... 1054, App. II Appendix II to Part 1054—Duty Cycles for Laboratory Testing (a) Test handheld engines with the following steady-state duty cycle: G3 mode No. Engine speed a Torque(percent) b Weighting...

Knee joint kinaesthesia and neuromuscular coordination during three phases of the menstrual cycle in moderately active women.

PubMed

Fridén, Cecilia; Hirschberg, Angelica Lindén; Saartok, Tönu; Renström, Per

2006-04-01

An increased incidence of sports related injuries in the premenstrual phase as well as in the menstrual phase of the menstrual cycle has been described. This may be explained by alterations in proprioception and neuromuscular coordination due to hormonal variations. Prospective, within women analysis of knee joint kinesthesia and neuromuscular coordination were performed by repeated measures analysis of variance in three hormonally verified phases of three consecutive menstrual cycles. Thirty-two healthy, moderately active female subjects volunteered to participate in the study. Twenty-five of the subjects performed at least one hormonally verified menstrual cycle. A specially designed device was used to investigate knee joint kinaesthesia and neuromuscular coordination was measured with the square hop test. These tests were carried out in the menstrual phase, ovulation phase and premenstrual phase determined by hormone analyses in three consecutive menstrual cycles. An impaired knee joint kinaesthesia was detected in the premenstrual phase and the performance of square hop test was significantly improved in the ovulation phase compared to the other two phases. The results of this study indicate that the variation of sex hormones in the menstrual cycle has an effect on performance of knee joint kinaesthesia and neuromuscular coordination.

Experimental and theoretical investigation of fatigue life in reusable rocket thrust chambers

NASA Technical Reports Server (NTRS)

Hannum, N. P.; Kasper, H. J.; Pavli, A. J.

1976-01-01

During a test program to investigate low-cycle thermal fatigue, 13 rocket combustion chambers were fabricated and cyclically test fired to failure. Six oxygen-free, high-conductivity (OFHC) copper and seven Amzirc chambers were tested. The failures in the OFHC copper chambers were not typical fatigue failures but are described as creep rupture enhanced by ratcheting. The coolant channels bulged toward the chamber centerline, resulting in progressive thinning of the wall during each cycle. The failures in the Amzirc alloy chambers were caused by low-cycle thermal fatigue. The zirconium in this alloy was not evenly distributed in the chamber materials. The life that was achieved was nominally the same as would have been predicted from OFHC copper isothermal test data.

EOS--AM1 Nickel Hydrogen Cell Interim Life Test Report

NASA Technical Reports Server (NTRS)

Bennett, C. W.; Keys, D. J.; Rao, G. M.; Wannemacher, H. E.; Vaidyanathan H.

1999-01-01

This paper reports the interim results of the Earth Observing System AM-1 project (EOS-AM-1) nickel hydrogen cell life test being conducted under contract to National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) at the Lockheed Martin Missiles and Space (LMMS) facility in East Windsor, NJ; and at COMSAT Labs., Clarksburg, MD. The purpose of the tests is to verify that the EOS-AM-1 cell design can meet five years of real-time Low Earth Orbit (LEO) cycling. The tests include both real-time LEO and accelerated stress tests. At LMMS, the first real-time LEO simulated 99 minute orbital cycle started on February 7, 1994 and the test has been running continuously since that time, with 18202 LEO cycles completed as of September 1, 1997. Each cycle consists of a 64 minute charge (VT at 1.507 volts per cell. 1.06 C/D ratio, followed by 0.6 ampere trickle charge) and a 35 minute constant power discharge at 177 watts (22.5% DOD). At COMSAT, the accelerated stress test consists of 90 minute orbital cycles at 60% DOD with a 30 minute discharge at 60 amperes and a 60 minute charge at 40 amperes (VT at 1.54 volts per cell to 1.09 C/D ratio, followed by 0.6 ampere trickle charge). The real-time LEO life test battery consists of seven, 50AH (nameplate rating) Eagle-Picher, Inc. (EPI) Mantech cells manufactured into three. 3-cell pack assemblies (there are two place holder cells that are not part of the life test electrical circuit). The test pack is configured to simulate the conductive thermal design of the spacecraft battery, including: conductive aluminum sleeves, 3-cell pack aluminum baseplate, and honeycomb panel all mounted to a liquid (-5 C) cold plate. The entire assembly is located in a thermal chamber operatina at +30 C. The accelerated stress test unit consists of five cells mounted in machined aluminum test sleeves and is operating at +10 C. The real-time LEO life test battery has met all performance requirements throuch the first 18,202 cycles, including: end of chargee and discharge cell voltages and voltace -radients; end of charge and discharge cell pressures; within cell and between cell temperature gradients; discharge capacity; current and power levels; and all charge parameters. The accelerated stress test battery has completed 11,998 cycles when the test was terminated. The stress test unit met all test parameters. This paper reports battery performances as a function of cycle life for both the real time LEO and the accelerated life test regimes.

EOS-AM1 Nickel Hydrogen Cell Interim Life Test Report

NASA Technical Reports Server (NTRS)

Bennett, Charles W.; Keys, D. J.; Rao, G. M.; Wannemacher, H. E.; Vaidyanathan, Hari

1998-01-01

This paper reports the interim results Earth Observing System AM-1 project (EOS-AM-1) nickel hydrogen cell life test being conducted under contract to National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) at the Lockheed Martin Missiles and Space (LMMS) facility in East Windsor, NJ; and at COMSAT Labs., Clarksburg, MD. The purpose of the tests is to verify that the EOS-AM-1 cell design can meet five years of real-time Low Earth Orbit (LEO) cycling. The tests include both real-time LEO and accelerated stress tests. At LMMS, the first real-time LEO simulated 99 minute orbital cycle started on February 7, 1994 and the test has been running continuously since that time, with 18202 LEO cycles completed as of September 1, 1997. Each cycle consists of a 64-minute charge (VT at 1,507 volts per cell, 1.06 C/D ratio, followed by 0.6 ampere trickle charge) and a 35 minute constant power discharge at 177 watts (22.5 percent DOD). At COMSAT, the accelerated stress test consists of 90 minute orbital cycles at 60 percent DOD with a 30 minute discharge at 60 amperes and a 60 minute charge at 40 amperes (VT at 1.54 volts per cell to 1.90 C/D ratio, followed by 0.6 ampere trickle charge). The real-time LEO life test battery consists of seven, 50AH (nameplate rating) Eagle-Picher, Inc. (EPI) Mantech cells manufactured into three, 3-cell pack assemblies (there are two place holder cells that are not part of the life test electrical circuit). The test pack is configured to simulate the conductive thermal design of the spacecraft battery, including: conductive aluminum sleeves, 3-cell pack aluminum baseplate, and honeycomb panel all mounted to a liquid (minus 5 deg) cold plate. The entire assembly is located in a thermal chamber operating at plus 3 deg. The accelerated stress test unit consists of five cells mounted in machined aluminum test sleeves and is operating at plus 10 deg. The real-time LEO life test battery has met all performance requirements through the first 18,202 cycles, including: end of charge and discharge cell voltages and voltage gradients; end of charge and discharge cells pressures; within cell and between cell temperature gradients dischare capacity; current and power levels; and all charge parameters. The accelerated stress test battery has completed 11998 cycles when the test was terminated. The stress test unit met all test parameters. This paper reports battery performances as a function of cycle life for both the real-time LEO and the accelerated life test regimes.

Reduction of capacity decay in vanadium flow batteries by an electrolyte-reflow method

NASA Astrophysics Data System (ADS)

Wang, Ke; Liu, Le; Xi, Jingyu; Wu, Zenghua; Qiu, Xinping

2017-01-01

Electrolyte imbalance is a major issue with Vanadium flow batteries (VFBs) as it has a significant impact on electrolyte utilization and cycle life over extended charge-discharge cycling. This work seeks to reduce capacity decay and prolong cycle life of VFBs by adopting a novel electrolyte-reflow method. Different current density and various start-up time of the method are investigated in the charge-discharge tests. The results show that the capacity decay rate is reduced markedly and the cycle life is prolonged substantially by this method. In addition, the coulomb efficiency, voltage efficiency and energy efficiency remain stable during the whole cycle life test, which indicates this method has little impact on the long lifetime performance of the VFBs. The method is low-cost, simple, effective, and can be applied in industrial VFB productions.

Residual Tensile Property of Plain Woven Jute Fiber/Poly(Lactic Acid) Green Composites during Thermal Cycling

PubMed Central

Katogi, Hideaki; Takemura, Kenichi; Akiyama, Motoki

2016-01-01

This study investigated the residual tensile properties of plain woven jute fiber reinforced poly(lactic acid) (PLA) during thermal cycling. Temperature ranges of thermal cycling tests were 35–45 °C and 35–55 °C. The maximum number of cycles was 103 cycles. The quasi-static tensile tests of jute fiber, PLA, and composite were conducted after thermal cycling tests. Thermal mechanical analyses of jute fiber and PLA were conducted after thermal cycling tests. Results led to the following conclusions. For temperatures of 35–45 °C, tensile strength of composite at 103 cycles decreased 10% compared to that of composite at 0 cycles. For temperatures of 35–55 °C, tensile strength and Young’s modulus of composite at 103 cycles decreased 15% and 10%, respectively, compared to that of composite at 0 cycles. Tensile properties and the coefficient of linear expansion of PLA and jute fiber remained almost unchanged after thermal cycling tests. From observation of a fracture surface, the length of fiber pull out in the fracture surface of composite at 103 cycles was longer than that of composite at 0 cycles. Therefore, tensile properties of the composite during thermal cycling were decreased, probably because of the decrease of interfacial adhesion between the fiber and resin. PMID:28773694

Thermal fatigue and oxidation data for alloy/braze combinations

NASA Technical Reports Server (NTRS)

Hill, V. L.; Humphreys, V. E.

1977-01-01

Thermal fatigue and oxidation data were obtained for 62 brazed specimens of 3 iron-, 3 nickel-, and 1 cobalt-base alloy. Fluidized bed thermal cycling was conducted over the range 740/25 C employing 10 cm long single-edge wedge specimens. Immersion time was always 4 minutes in each bed. Types of test specimens employed in the program include those with brazed overlays on the specimen radius, those butt brazed at midspan and those with a brazed foil overlay on the specimen radius. Of the 18 braze overlay specimens, 5 generated fatigue cracks by 7000 cycles. Thermal cracking of butt brazed specimens occurred exclusively through the butt braze. Of the 23 butt brazed specimens, 7 survived 11,000 thermal cycles without cracking. Only 2 of the 21 foil overlaid specimens exhibiting cracking in 7,000 cycles. Blistering of the foil did occur for 2 alloys by 500 cycles. Oxidation of the alloy/braze combination was limited at the test maximum test temperature of 740 C.

Identification of fuel cycle simulator functionalities for analysis of transition to a new fuel cycle

DOE PAGES

Brown, Nicholas R.; Carlsen, Brett W.; Dixon, Brent W.; ...

2016-06-09

Dynamic fuel cycle simulation tools are intended to model holistic transient nuclear fuel cycle scenarios. As with all simulation tools, fuel cycle simulators require verification through unit tests, benchmark cases, and integral tests. Model validation is a vital aspect as well. Although compara-tive studies have been performed, there is no comprehensive unit test and benchmark library for fuel cycle simulator tools. The objective of this paper is to identify the must test functionalities of a fuel cycle simulator tool within the context of specific problems of interest to the Fuel Cycle Options Campaign within the U.S. Department of Energy smore » Office of Nuclear Energy. The approach in this paper identifies the features needed to cover the range of promising fuel cycle options identified in the DOE-NE Fuel Cycle Evaluation and Screening (E&S) and categorizes these features to facilitate prioritization. Features were categorized as essential functions, integrating features, and exemplary capabilities. One objective of this paper is to propose a library of unit tests applicable to each of the essential functions. Another underlying motivation for this paper is to encourage an international dialog on the functionalities and standard test methods for fuel cycle simulator tools.« less

Eryptosis and hemorheological responses to maximal exercise in athletes: Comparison between running and cycling.

PubMed

Nader, E; Guillot, N; Lavorel, L; Hancco, I; Fort, R; Stauffer, E; Renoux, C; Joly, P; Germain, M; Connes, P

2018-05-01

We compared the effects of cycling and running exercise on hemorheological and hematological properties, as well as eryptosis markers. Seven endurance-trained subjects randomly performed a progressive and maximal exercise test on a cycle ergometer and a treadmill. Blood was sampled at rest and at the end of the exercise to analyze hematological and blood rheological parameters including hematocrit (Hct), red blood cell (RBC) deformability, aggregation, and blood viscosity. Hemoglobin saturation (SpO2), blood lactate, and glucose levels were also monitored. Red blood cell oxidative stress, calcium content, and phosphatidylserine exposure were determined by flow cytometry to assess eryptosis level. Cycling exercise increased blood viscosity and RBC aggregation whereas it had no significant effect on RBC deformability. In contrast, blood viscosity remained unchanged and RBC deformability increased with running. The increase in Hct, lactate, and glucose concentrations and the loss of weight at the end of exercise were not different between running and cycling. Eryptosis markers were not affected by exercise. A significant drop in SpO2 was noted during running but not during cycling. Our study showed that a progressive and maximal exercise test conducted on a cycle ergometer increased blood viscosity while the same test conducted on a treadmill did not change this parameter because of different RBC rheological behavior between the 2 tests. We also demonstrated that a short maximal exercise does not alter RBC physiology in trained athletes. We suspect that exercise-induced hypoxemia occurring during running could be at the origin of the RBC rheological behavior differences with cycling. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

High frequency pulsed electromigration

NASA Astrophysics Data System (ADS)

Malone, David Wayne

Electromigration life tests were performed on copper-alloyed aluminum test structures that were representative of modern CMOS metallization schemes, complete with Ti/TiN cladding layers and a tungsten-plug contact at the cathode. A total of 18 electrical stress treatments were applied. One was a DC current of 15 mA. The other 17 were pulsed currents, varied according to duty cycle and frequency. The pulse amplitude was 15 mA (˜2.7 × 10sp6 A/cmsp2) for all treatments. Duty cycles ranged from 33.3% to 80%, and frequencies fell into three rough ranges-100 KHz, 1 MHz, and 100 MHz. The ambient test temperature was 200sp°C in all experiments. Six to 9 samples were subjected to each treatment. Experimental data were gathered in the form of test stripe resistance versus time, R(t). For purposes of lifetime analysis, "failure" was defined by the criterion R(t)/R(0) = 1.10, and the median time to failure, tsb{50}, was used as the primary basis of comparison between test groups. It was found that the dependence of tsb{50} on pulse duty cycle conformed rather well to the so-called "average current density model" for duty cycles of 50% and higher. Lifetimes were less enhanced for a duty cycle of 33.3%, but they were still considerably longer than an "on-time" model would predict. No specific dependence of tsb{50} on pulse frequency was revealed by the data, that is, reasonably good predictions of tsb{50} could be made by recognizing the dominant influence of duty cycle. These findings confirm that IC miniaturization can be more aggressively pursued than an on-time prediction would allow. It is significant that this was found to be true for frequencies on the order of 100 MHz, where many present day digital applications operate. Post-test optical micrographs were obtained for each test subject in order to determine the location of electromigration damage. The pulse duty cycle was found to influence the location. Most damage occurred at the cathode contact, regardless of treatment conditions, but there was an increased incidence of damage farther downwind with decreasing duty cycle. This tendency and the deviation from the average current density model for small duty cycles were explained in terms of the Blech length, its dependence on microstructure and duty cycle, and its impact on the relative rates of damage and recovery.

Evaluation of a new rapid readout biological indicator for use in 132°C and 135°C vacuum-assisted steam sterilization cycles.

PubMed

Schneider, Philip M

2014-02-01

Sterilization is a process that cannot be inspected or tested in a practical manner to assure that all microorganisms have been inactivated. The process must therefore be validated for all of the specific items processed or monitored on a per cycle basis. A new, faster rapid readout biological indicator (RRBI) has been developed for use in 132°C and 135°C vacuum-assisted steam sterilization cycles. The aim of this study was to evaluate the performance of this new 1-hour readout RRBI at 132°C in side-by-side testing with an existing 3-hour readout RRBI and also evaluate the performance of the new RRBI in 135°C cycles. Readout responses of 1 hour (fluorescent) and 48 hours and 7 days (growth) of the new RRBI were compared with 3-hour, 48-hour, and 7-day readouts of the 3-hour RRBI following exposures in 132°C cycles using a highly controlled test vessel, ie, a steam resistometer. Additional testing of the 1-hour RRBIs was also performed in 135°C cycles. The number and percentage of fluorescent-positive 1-hour RRBIs were virtually identical to those of the 3-hour RRBIs after 1 and 3 hours of incubation, respectively. Testing of the 1-hour RRBI in 135°C cycles paralleled the results of the testing at 132°C but with the expected shorter exposure times. The results of this study suggest that the 1-hour RRBI is equivalent to the 3-hour RRBI and would be suitable for use in monitoring dynamic air removal steam sterilization cycles at both 132°C and 135°C per recommended practice guidelines. Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Alternatives to the Six-Minute Walk Test in Pulmonary Arterial Hypertension

PubMed Central

Mainguy, Vincent; Malenfant, Simon; Neyron, Anne-Sophie; Saey, Didier; Maltais, François; Bonnet, Sébastien; Provencher, Steeve

2014-01-01

Introduction The physiological response during the endurance shuttle walk test (ESWT), the cycle endurance test (CET) and the incremental shuttle walk test (ISWT) remains unknown in PAH. We tested the hypothesis that endurance tests induce a near-maximal physiological demand comparable to incremental tests. We also hypothesized that differences in respiratory response during exercise would be related to the characteristics of the exercise tests. Methods Within two weeks, twenty-one PAH patients (mean age: 54(15) years; mean pulmonary arterial pressure: 42(12) mmHg) completed two cycling exercise tests (incremental cardiopulmonary cycling exercise test (CPET) and CET) and three field tests (ISWT, ESWT and six-minute walk test (6MWT)). Physiological parameters were continuously monitored using the same portable telemetric device. Results Peak oxygen consumption (VO2peak) was similar amongst the five exercise tests (p = 0.90 by ANOVA). Walking distance correlated markedly with the VO2peak reached during field tests, especially when weight was taken into account. At 100% exercise, most physiological parameters were similar between incremental and endurance tests. However, the trends overtime differed. In the incremental tests, slopes for these parameters rose steadily over the entire duration of the tests, whereas in the endurance tests, slopes rose sharply from baseline to 25% of maximum exercise at which point they appeared far less steep until test end. Moreover, cycling exercise tests induced higher respiratory exchange ratio, ventilatory demand and enhanced leg fatigue measured subjectively and objectively. Conclusion Endurance tests induce a maximal physiological demand in PAH. Differences in peak respiratory response during exercise are related to the modality (cycling vs. walking) rather than the progression (endurance vs. incremental) of the exercise tests. PMID:25111294

Alternatives to the six-minute walk test in pulmonary arterial hypertension.

PubMed

Mainguy, Vincent; Malenfant, Simon; Neyron, Anne-Sophie; Saey, Didier; Maltais, François; Bonnet, Sébastien; Provencher, Steeve

2014-01-01

The physiological response during the endurance shuttle walk test (ESWT), the cycle endurance test (CET) and the incremental shuttle walk test (ISWT) remains unknown in PAH. We tested the hypothesis that endurance tests induce a near-maximal physiological demand comparable to incremental tests. We also hypothesized that differences in respiratory response during exercise would be related to the characteristics of the exercise tests. Within two weeks, twenty-one PAH patients (mean age: 54(15) years; mean pulmonary arterial pressure: 42(12) mmHg) completed two cycling exercise tests (incremental cardiopulmonary cycling exercise test (CPET) and CET) and three field tests (ISWT, ESWT and six-minute walk test (6MWT)). Physiological parameters were continuously monitored using the same portable telemetric device. Peak oxygen consumption (VO(2peak)) was similar amongst the five exercise tests (p = 0.90 by ANOVA). Walking distance correlated markedly with the VO(2peak) reached during field tests, especially when weight was taken into account. At 100% exercise, most physiological parameters were similar between incremental and endurance tests. However, the trends overtime differed. In the incremental tests, slopes for these parameters rose steadily over the entire duration of the tests, whereas in the endurance tests, slopes rose sharply from baseline to 25% of maximum exercise at which point they appeared far less steep until test end. Moreover, cycling exercise tests induced higher respiratory exchange ratio, ventilatory demand and enhanced leg fatigue measured subjectively and objectively. Endurance tests induce a maximal physiological demand in PAH. Differences in peak respiratory response during exercise are related to the modality (cycling vs. walking) rather than the progression (endurance vs. incremental) of the exercise tests.

EOS-AM1 Nickel Hydrogen Cell

NASA Technical Reports Server (NTRS)

Bennett, Charles W.; Keys, Denney J.; Rao, Gopalakrishna M.; Wannemacher, Hari E.; Vaidyanathan, Harry

1997-01-01

This paper reports the interim results of the Earth Observing System AM-1 project (EOS-AM-1) nickel hydrogen cell life test being conducted under contract to National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) at the Lockheed Martin Missile and Space (LMMS) facility in East Windsor, NJ; and at COMSAT Labs., Clarksburg, MD. The purpose of die tests is to verify that the EOS-AM-1 cell design can meet five years of real-time Low Earth Orbit (LEO) cycling. The tests include both real-time LEO and accelerated stress tests. At LMMS, the first real-time LEO simulated 99 minute orbital cycle started on February 7, 1994 and the test has been running continuously since that time, with 18,202 LEO cycles completed as of September 1, 1997. Each cycle consists of a 64 minute charge (VT at 1.507 volts per cell, 1.06 C/D ratio, followed by 0.6 ampere trickle charge) and a 35 minute constant power discharge at 177 watts (22.5% DOD). At COMSAT, the accelerated stress test consists of 90 minute orbital cycles at 60% DOD with a 30 minute discharge at 60 amperes and a 60 minute charge at 40 amperes (VT at 1.54 volts per cell to 1.09 C/D ratio, followed by 0.6 ampere trickle charge). The real-time LEO life test battery consists of seven, 50AH (nameplate rating) Eagle-Picher, Inc. (EPI) Mantech cells manufactured into three, 3-cell pack assemblies (there are two place holder cells that are not part of the life test electrical circuit). The test pack is configured to simulate the conductive thermal design of the spacecraft battery, including: conductive aluminum sleeves, 3-cell pack aluminum baseplate, and honeycomb panel all mounted to a liquid (-5 C) cold plate. The entire assembly is located in a thermal chamber operating at +30 C. The accelerated stress test unit consists of five cells mounted in machined aluminum test sleeves and is operating at +10 C. The real-time LEO life test battery has met all performance requirements through the first 18,202 cycles, including: end of charge mid discharge cell voltages and voltage gradients; end of charge and discharge cell pressures; within cell and between cell temperature gradients; discharge capacity; current and power levels; and all charge parameters. The accelerated stress test battery has completed 11,998 cycles when the test was terminated. The stress test unit met all test parameters. This paper reports battery perfortnances as a funcfion of cycle life for both the real-time LEO and the accelerated life test regimes.

Fatigue Behavior of Crystalline-Reinforced Glass-Ceramics.

PubMed

Vicari, Carolina Barbosa; Magalhães, Bárbara de Oliveira; Griggs, Jason Alan; Borba, Márcia

2018-01-03

To evaluate the fatigue behavior of two crystalline-reinforced ceramics: leucite-reinforced (VL) and lithium disilicate-based (VD) glass-ceramics. Bar-shaped specimens (16 × 4 × 1.2 mm) were produced for each ceramic using prefabricated CAD/CAM blocks. For each group, 30 specimens were subjected to a three-point flexural strength test in a universal testing machine. For VL and VD, 36 and 41 specimens were subjected to a cyclic fatigue test, respectively. The cyclic fatigue test was performed with a pneumatic mechanical cycling machine (1 Hz; 37°C distilled water). Specimens were tested at two stress levels for each preset lifetime (10 3 and 10 4 cycles for VL; 10 4 and 10 5 cycles for VD) following the boundary technique. Fractography was performed with a scanning electron microscope. Data were analyzed with Weibull analysis. There were significant differences among groups for characteristic strength (σ 0 ) and Weibull modulus (m), as the confidence intervals did not overlap. The VD group presented the highest values of σ 0 , but the lowest Weibull modulus. Both groups showed a reduction of approximately 60% of the initial flexural strength (σ f ) after cycling for 10 4 cycles. For VD tested in fatigue, there was no degradation of σ f when the number of cycles was increased from 10 4 to 10 5 . The VL group showed an 18% decrease in σ f when the number of cycles increased from 10 3 to 10 4 . Flexural strength values estimated for a 5% probability of failure were 36 MPa for VL and 55 MPa for VD, after 10 4 cycles. Both glass-ceramics showed similar strength degradation (60%) after a lifetime of 10 4 cycles, despite their distinct mechanical properties. Mechanical cycling in humid conditions proved to be an important factor for the degradation of the mechanical properties of crystalline-reinforced glass-ceramics. © 2018 by the American College of Prosthodontists.

A Guide to Understanding Security Testing and Test Documentation in Trusted Systems, Version 1

DTIC Science & Technology

1993-07-01

necessary to allow the testing of access with all other types of objects. The above test data also provide partial coverage because they de not include...two types of assurance are needed. They are life-cycle assurance and operational assurance. "Life-cycle assurance refers to steps taken by an...procedures depends to a certain extent on the nature of the TCB interface under test. For example, for most TCB-primitive tests that require the same type

Life prediction and reliability assessment of lithium secondary batteries

NASA Astrophysics Data System (ADS)

Eom, Seung-Wook; Kim, Min-Kyu; Kim, Ick-Jun; Moon, Seong-In; Sun, Yang-Kook; Kim, Hyun-Soo

Reliability assessment of lithium secondary batteries was mainly considered. Shape parameter (β) and scale parameter (η) were calculated from experimental data based on cycle life test. We also examined safety characteristics of lithium secondary batteries. As proposed by IEC 62133 (2002), we had performed all of the safety/abuse tests such as 'mechanical abuse tests', 'environmental abuse tests', 'electrical abuse tests'. This paper describes the cycle life of lithium secondary batteries, FMEA (failure modes and effects analysis) and the safety/abuse tests we had performed.

10 CFR Appendix C to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Dishwashers

Code of Federal Regulations, 2014 CFR

2014-01-01

... Preconditioning cycle means any cycle that includes a fill, circulation, and drain to ensure that the water lines... truncated normal cycle without a test load if the dishwasher does not heat water in the normal cycle. 2.6.2... water temperatures encountered in the test cycle. 3.4 Water pressure gauge. The water pressure gauge...

NASA's Evolutionary Xenon Thruster (NEXT) Component Verification Testing

NASA Technical Reports Server (NTRS)

Herman, Daniel A.; Pinero, Luis R.; Sovey, James S.

2009-01-01

Component testing is a critical facet of the comprehensive thruster life validation strategy devised by the NASA s Evolutionary Xenon Thruster (NEXT) program. Component testing to-date has consisted of long-duration high voltage propellant isolator and high-cycle heater life validation testing. The high voltage propellant isolator, a heritage design, will be operated under different environmental condition in the NEXT ion thruster requiring verification testing. The life test of two NEXT isolators was initiated with comparable voltage and pressure conditions with a higher temperature than measured for the NEXT prototype-model thruster. To date the NEXT isolators have accumulated 18,300 h of operation. Measurements indicate a negligible increase in leakage current over the testing duration to date. NEXT 1/2 in. heaters, whose manufacturing and control processes have heritage, were selected for verification testing based upon the change in physical dimensions resulting in a higher operating voltage as well as potential differences in thermal environment. The heater fabrication processes, developed for the International Space Station (ISS) plasma contactor hollow cathode assembly, were utilized with modification of heater dimensions to accommodate a larger cathode. Cyclic testing of five 1/22 in. diameter heaters was initiated to validate these modified fabrication processes while retaining high reliability heaters. To date two of the heaters have been cycled to 10,000 cycles and suspended to preserve hardware. Three of the heaters have been cycled to failure giving a B10 life of 12,615 cycles, approximately 6,000 more cycles than the established qualification B10 life of the ISS plasma contactor heaters.

40 CFR 91.410 - Engine test cycle.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine test cycle. 91.410 Section 91.410 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... test cycle. (a) The 5-mode cycle specified in Table 2 in appendix A to this subpart shall be followed...

40 CFR 86.336-79 - Diesel engine test cycle.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Diesel engine test cycle. 86.336-79 Section 86.336-79 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... Diesel engine test cycle. (a) The following 13-mode cycle shall be followed in dynamometer operation...

40 CFR 1037.510 - Duty-cycle exhaust testing.

Code of Federal Regulations, 2013 CFR

2013-07-01

... part 86. For cruise cycle testing of vehicles equipped with cruise control, use the vehicle's cruise... CONTROLS CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES Test and Modeling Procedures § 1037.510...: variable speeds for the transient test and constant speeds for the cruise tests. None of these cycles...

40 CFR 1037.510 - Duty-cycle exhaust testing.

Code of Federal Regulations, 2012 CFR

2012-07-01

... part 86. For cruise cycle testing of vehicles equipped with cruise control, use the vehicle's cruise... CONTROLS CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES Test and Modeling Procedures § 1037.510...: variable speeds for the transient test and constant speeds for the cruise tests. None of these cycles...

40 CFR 1037.510 - Duty-cycle exhaust testing.

Code of Federal Regulations, 2014 CFR

2014-07-01

... part 86. For cruise cycle testing of vehicles equipped with cruise control, use the vehicle's cruise... CONTROLS CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES Test and Modeling Procedures § 1037.510...: variable speeds for the transient test and constant speeds for the cruise tests. None of these cycles...

Electro-Optic Fabrics for the Warrior of the 21st Century - Phase II

DTIC Science & Technology

2010-01-01

46 28. Effect of 1000 cycles of hex- abrasion testing on Fire Wire cable .................................... 46 UNCLASSIFIED vi 29. Close...49 32. Effect of 2000 cycles of hex- abrasion testing on Fire Wire cable .................................... 49 33. Effect of 4000 cycles of...hex- abrasion testing on Fire Wire cable .................................... 50 34. Effect of 2000 cycles of hex- abrasion testing on USB v2 cable

Evaluating the contributions of task expectancy in the testing and guessing benefits on recognition memory.

PubMed

Huff, Mark J; Yates, Tyler J; Balota, David A

2018-05-03

Recently, we have shown that two types of initial testing (recall of a list or guessing of critical items repeated over 12 study/test cycles) improved final recognition of related and unrelated word lists relative to restudy. These benefits were eliminated, however, when test instructions were manipulated within subjects and presented after study of each list, procedures designed to minimise expectancy of a specific type of upcoming test [Huff, Balota, & Hutchison, 2016. The costs and benefits of testing and guessing on recognition memory. Journal of Experimental Psychology: Learning, Memory, and Cognition, 42, 1559-1572. doi: 10.1037/xlm0000269 ], suggesting that testing and guessing effects may be influenced by encoding strategies specific for the type of upcoming task. We follow-up these experiments by examining test-expectancy processes in guessing and testing. Testing and guessing benefits over restudy were not found when test instructions were presented either after (Experiment 1) or before (Experiment 2) a single study/task cycle was completed, nor were benefits found when instructions were presented before study/task cycles and the task was repeated three times (Experiment 3). Testing and guessing benefits emerged only when instructions were presented before a study/task cycle and the task was repeated six times (Experiments 4A and 4B). These experiments demonstrate that initial testing and guessing can produce memory benefits in recognition, but only following substantial task repetitions which likely promote task-expectancy processes.

Development of a new assessment tool for cervical myelopathy using hand-tracking sensor: Part 2: normative values.

PubMed

Alagha, M Abdulhadi; Alagha, Mahmoud A; Dunstan, Eleanor; Sperwer, Olaf; Timmins, Kate A; Boszczyk, Bronek M

2017-04-01

To set a baseline measurement of the number of hand flexion-extension cycles and analyse the degree of motion in young healthy individuals, measured by leap motion controller (LMC), besides describing gender and dominant hand differences. Fifty healthy participants were asked to fully grip-and-release their dominant hand as rapidly as possible for a maximum of 3 min or until subjects fatigued, while wearing a non-metal wrist splint. Participants also performed a 15-s grip-and-release test. An assessor blindly counted the frequency of grip-and-release cycles and magnitude of motion from the LMC data. The mean number of the 15-s G-R cycles recorded by LMC was: 47.7 ± 6.5 (test 1, LMC); and 50.2 ± 6.5 (test 2, LMC). In the 3-min test, the total number of hand flexion-extension cycles and the degree of motion decreased as the person fatigued. However, the decline in frequency preceded that of motion's magnitude. The mean frequency of cycles per 10-s interval decreased from 35.4 to 26.6 over the 3 min. Participants reached fatigue from 59.38 s; 43 participants were able to complete the 3-min test. Normative values of the frequency of cycles and extent of motion for young healthy individuals, aged 18-35 years, are provided. Future work is needed to establish values in a wider age range and in a clinical setting.

Effect of storage and LEO cycling on manufacturing technology IPV nickel-hydrogen cells

NASA Technical Reports Server (NTRS)

Smithrick, John J.

1987-01-01

Yardney Manufacturing Technology (MANTECH) 50 A-hr space weight individual pressure vessel nickel-hydrogen cells were evaluated. This consisted of investigating: the effect of storage and charge/discharge cycling on cell performance. For the storage test the cells were precharged with hydrogen, by the manufacturer, to a pressure of 14.5 psia. After undergoing activation and acceptance tests, the cells were discharged at C/10 rate (5A) to 0.1 V or less. The terminals were then shorted. The cells were shipped to NASA Lewis Research Center where they were stored at room temperature in the shorted condition for 1 year. After storage, the acceptance tests were repeated at NASA Lewis. A comparison of test results indicate no significant degradation in electrical performance due to 1 year storage. For the cycle life test the regime was a 90 minute low earth orbit at deep depths of discharge (80 and 60 percent). At the 80 percent DOD the three cells failed on the average at cycle 741. Failure for this test was defined to occur when the cell voltage degraded to 1 V prior to completion of the 35 min discharge. The DOD was reduced to 60 percent. The cycle life test was continued.

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.

Effects of thermal and mechanical fatigue on the flexural strength of G40-600/PMR-15 cross-ply laminates

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

Roberts, G.D.; Ho, B.Ping Hsiao; Wallace, J.F.

1993-02-01

The effects of thermal and mechanical fatigue on the flexural strength of G40-600/PMR-15 cross-ply laminates with ply orientation of (0(2),90(2))2S and (90(2),0(2))2S are examined. The relative importance of shear and tensile stresses is examined by varying the span-to-depth ratios of flexural test specimens from 8 to 45. Acoustic emission signals are measured during the flexural tests in order to monitor the initiation and growth of damage. Optical microscopy is used to examine specimens for resin cracking, delamination, and fiber breaks after testing. Transverse matrix cracks and delaminations occur in all specimens, regardless of ply orientation, span-to-depth ratio, or previous exposuremore » of specimens to thermal and mechanical fatigue. A small amount of fiber tensile fracture occurs in the outer 0 deg ply of specimens with high span-to-depth ratios. Because of the complex failure modes, the flexural test results represent the apparent strengths rather than the true flexural or shear strengths for these cross-ply laminates. Thermal cycling of specimens prior to flexural testing does not reduce the apparent flexural strength or change the mode of failure. However, fewer acoustic events are recorded at all strains during flexural testing of specimens exposed to prior thermal cycling. High temperature thermal cycling (32 to 260 C, 100 cycles) causes a greater reduction in acoustic events than low temperature thermal cycling (-85 to +85 C, 500 cycles). Mechanical cycling (0 to 50 percent of the flexural strength, 100 cycles) has a similar effect, except that acoustic events are reduced only at strains less than the maximum strain applied during flexural fatigue.« less

Effects of thermal and mechanical fatigue on the flexural strength of G40-600/PMR-15 cross-ply laminates

NASA Technical Reports Server (NTRS)

Roberts, Gary D.; Ho, Barry Ping Hsiao; Wallace, John F.

1993-01-01

The effects of thermal and mechanical fatigue on the flexural strength of G40-600/PMR-15 cross-ply laminates with ply orientation of (0(2),90(2))2S and (90(2),0(2))2S are examined. The relative importance of shear and tensile stresses is examined by varying the span-to-depth ratios of flexural test specimens from 8 to 45. Acoustic emission signals are measured during the flexural tests in order to monitor the initiation and growth of damage. Optical microscopy is used to examine specimens for resin cracking, delamination, and fiber breaks after testing. Transverse matrix cracks and delaminations occur in all specimens, regardless of ply orientation, span-to-depth ratio, or previous exposure of specimens to thermal and mechanical fatigue. A small amount of fiber tensile fracture occurs in the outer 0 deg ply of specimens with high span-to-depth ratios. Because of the complex failure modes, the flexural test results represent the 'apparent' strengths rather than the true flexural or shear strengths for these cross-ply laminates. Thermal cycling of specimens prior to flexural testing does not reduce the apparent flexural strength or change the mode of failure. However, fewer acoustic events are recorded at all strains during flexural testing of specimens exposed to prior thermal cycling. High temperature thermal cycling (32 to 260 C, 100 cycles) causes a greater reduction in acoustic events than low temperature thermal cycling (-85 to +85 C, 500 cycles). Mechanical cycling (0 to 50 percent of the flexural strength, 100 cycles) has a similar effect, except that acoustic events are reduced only at strains less than the maximum strain applied during flexural fatigue.

NASA Flexible Screen Propellant Management Device (PMD) Demonstration With Cryogenic Liquid

NASA Technical Reports Server (NTRS)

Wollen, Mark; Bakke, Victor; Baker, James

2012-01-01

While evaluating various options for liquid methane and liquid oxygen propellant management for lunar missions, Innovative Engineering Solutions (IES) conceived the flexible screen device as a potential simple alternative to conventional propellant management devices (PMD). An apparatus was designed and fabricated to test flexible screen devices in liquid nitrogen. After resolution of a number of issues (discussed in detail in the paper), a fine mesh screen (325 by 2300 wires per inch) spring return assembly was successfully tested. No significant degradation in the screen bubble point was observed either due to the screen stretching process or due to cyclic fatigue during testing. An estimated 30 to 50 deflection cycles, and approximately 3 to 5 thermal cycles, were performed on the final screen specimen, prior to and between formally recorded testing. These cycles included some "abusive" pressure cycling, where gas or liquid was driven through the screen at rates that produced differential pressures across the screen of several times the bubble point pressure. No obvious performance degradation or other changes were observed over the duration of testing. In summary, it is felt by the author that these simple tests validated the feasibility of the flexible screen PMD concept for use with cryogenic propellants.

Cycle life status of SAFT VOS nickel-cadmium cells

NASA Technical Reports Server (NTRS)

Goualard, Jacques

1993-01-01

The SAFT prismatic VOS Ni-Cd cells have been flown in geosynchronous orbit since 1977 and in low earth orbit since 1983. Parallel cycling tests are performed by several space agencies in order to determine the cycle life for a wide range of temperature and depth of discharge (DOD). In low Earth orbit (LEO), the ELAN program is conducted on 24 Ah cells by CNES and ESA at the European Battery Test Center at temperatures ranging from 0 to 27 C and DOD from 10 to 40 percent. Data are presented up to 37,000 cycles. One pack (X-80) has achieved 49,000 cycles at 10 C and 23 percent DOD. The geosynchronous orbit simulation of a high DOD test is conducted by ESA on 3 batteries at 10 C and 70, 90, and 100 percent DOD. Thirty-one eclipse seasons are completed, and no signs of degradation have been found. The Air Force test at CRANE on 24 Ah and 40 Ah cells at 20 C and 80 percent DOD has achieved 19 shadow periods. Life expectancy is discussed. The VOS cell technology could be used for the following: (1) in geosynchronous conditions--15 yrs at 10-15 C and 80 percent DOD; and (2) in low earth orbit--10 yrs at 5-15 C and 25-30 percent DOD.

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

Brown, Nicholas R.; Carlsen, Brett W.; Dixon, Brent W.

Dynamic fuel cycle simulation tools are intended to model holistic transient nuclear fuel cycle scenarios. As with all simulation tools, fuel cycle simulators require verification through unit tests, benchmark cases, and integral tests. Model validation is a vital aspect as well. Although compara-tive studies have been performed, there is no comprehensive unit test and benchmark library for fuel cycle simulator tools. The objective of this paper is to identify the must test functionalities of a fuel cycle simulator tool within the context of specific problems of interest to the Fuel Cycle Options Campaign within the U.S. Department of Energy smore » Office of Nuclear Energy. The approach in this paper identifies the features needed to cover the range of promising fuel cycle options identified in the DOE-NE Fuel Cycle Evaluation and Screening (E&S) and categorizes these features to facilitate prioritization. Features were categorized as essential functions, integrating features, and exemplary capabilities. One objective of this paper is to propose a library of unit tests applicable to each of the essential functions. Another underlying motivation for this paper is to encourage an international dialog on the functionalities and standard test methods for fuel cycle simulator tools.« less

A systems approach to solder joint fatigue in spacecraft electronic packaging

NASA Technical Reports Server (NTRS)

Ross, R. G., Jr.

1991-01-01

Differential expansion induced fatigue resulting from temperature cycling is a leading cause of solder joint failures in spacecraft. Achieving high reliability flight hardware requires that each element of the fatigue issue be addressed carefully. This includes defining the complete thermal-cycle environment to be experienced by the hardware, developing electronic packaging concepts that are consistent with the defined environments, and validating the completed designs with a thorough qualification and acceptance test program. This paper describes a useful systems approach to solder fatigue based principally on the fundamental log-strain versus log-cycles-to-failure behavior of fatigue. This fundamental behavior has been useful to integrate diverse ground test and flight operational thermal-cycle environments into a unified electronics design approach. Each element of the approach reflects both the mechanism physics that control solder fatigue, as well as the practical realities of the hardware build, test, delivery, and application cycle.

40 CFR 86.1362-2007 - Steady-state testing with a ramped-modal cycle.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-modal cycle. 86.1362-2007 Section 86.1362-2007 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... (CONTINUED) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1362-2007 Steady-state testing with a ramped-modal cycle. This section...

40 CFR 86.1362-2010 - Steady-state testing with a ramped-modal cycle.

Code of Federal Regulations, 2010 CFR

2010-07-01

...-modal cycle. 86.1362-2010 Section 86.1362-2010 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... (CONTINUED) Emission Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1362-2010 Steady-state testing with a ramped-modal cycle. This section...

40 CFR 86.1341-98 - Test cycle validation criteria.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 20 2012-07-01 2012-07-01 false Test cycle validation criteria. 86... Procedures § 86.1341-98 Test cycle validation criteria. Section 86.1341-98 includes text that specifies...-90 (d)(4), shall be excluded from both cycle validation and the integrated work used for emissions...

40 CFR 86.1341-98 - Test cycle validation criteria.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 20 2013-07-01 2013-07-01 false Test cycle validation criteria. 86... Procedures § 86.1341-98 Test cycle validation criteria. Section 86.1341-98 includes text that specifies...-90 (d)(4), shall be excluded from both cycle validation and the integrated work used for emissions...

40 CFR 86.1341-98 - Test cycle validation criteria.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Test cycle validation criteria. 86... Procedures § 86.1341-98 Test cycle validation criteria. Section 86.1341-98 includes text that specifies...-90 (d)(4), shall be excluded from both cycle validation and the integrated work used for emissions...

40 CFR Table 6 to Subpart IIIi of... - Optional 3-Mode Test Cycle for Stationary Fire Pump Engines

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Optional 3-Mode Test Cycle for.... IIII, Table 6 Table 6 to Subpart IIII of Part 60—Optional 3-Mode Test Cycle for Stationary Fire Pump Engines [As stated in § 60.4210(g), manufacturers of fire pump engines may use the following test cycle...

Low cycle fatigue properties of MAR-M-246 Hf in hydrogen. [a cast nickel-base alloy

NASA Technical Reports Server (NTRS)

Warren, J. R.

1979-01-01

The transverse, low cycle fatigue properties were determined for directionally solidified and single crystal samples of a cast nickel-base alloy proposed for use in space propulsion systems in pure or partial high pressure hydrogen environments at elevated temperatures. The test temperature was 760 C (1400F) and the pressure of the gaseous hydrogen was 34.5 MPa (5000 psig). Low cycle fatique life was established by strain controlled testing using smooth specimens and a servohydraulic closed-loop test machine modified with a high pressure environmental chamber. Results and conclusions are discussed.

40 CFR 86.335-79 - Gasoline-fueled engine test cycle.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Gasoline-fueled engine test cycle. 86... Regulations for New Gasoline-Fueled and Diesel-Fueled Heavy-Duty Engines; Gaseous Exhaust Test Procedures § 86.335-79 Gasoline-fueled engine test cycle. (a) The following test sequence shall be followed in...

40 CFR 86.335-79 - Gasoline-fueled engine test cycle.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Gasoline-fueled engine test cycle. 86... Regulations for New Gasoline-Fueled and Diesel-Fueled Heavy-Duty Engines; Gaseous Exhaust Test Procedures § 86.335-79 Gasoline-fueled engine test cycle. (a) The following test sequence shall be followed in...

40 CFR 86.335-79 - Gasoline-fueled engine test cycle.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Gasoline-fueled engine test cycle. 86... Regulations for New Gasoline-Fueled and Diesel-Fueled Heavy-Duty Engines; Gaseous Exhaust Test Procedures § 86.335-79 Gasoline-fueled engine test cycle. (a) The following test sequence shall be followed in...

High temperature, low-cycle fatigue of copper-base alloys for rocket nozzles. Part 2: Strainrange partitioning and low-cycle fatigue results at 538 deg C

NASA Technical Reports Server (NTRS)

Conway, J. B.; Stentz, R. H.; Berling, J. T.

1976-01-01

Low-cycle fatigue tests of 1/2 Hard AMZIRC Copper and NARloy Z were performed in argon at 538 C to determine partitioned strain range versus life relationships. Strain-controlled low-cycle fatigue tests of a Zr-Cr-Mg copper-base alloy were also performed. Strain ranges, lower than those employed in previous tests, were imposed in order to extend the fatigue life curve out to approximately 400,000 cycles. An experimental copper alloy and an experimental silver alloy were also studied. Tensile tests were performed in air at room temperature and in argon at 538 C. Strain-controlled low-cycle fatigue tests were performed at 538 C in argon to define the fatigue life over the regime from 300 to 3,000 cycles. For the silver alloy, three additional heat treatments were introduced, and a limited evaluation of the short-term tensile and low-cycle fatigue behavior at 538 C was performed.

On Determining the Rise, Size, and Duration Classes of a Sunspot Cycle

NASA Astrophysics Data System (ADS)

Wilson, Robert M.; Hathaway, David H.; Reichmann, Edwin J.

1996-09-01

The behavior of ascent duration, maximum amplitude, and period for cycles 1 to 21 suggests that they are not mutually independent. Analysis of the resultant three-dimensional contingency table for cycles divided according to rise time (ascent duration), size (maximum amplitude), and duration (period) yields a chi-square statistic (= 18.59) that is larger than the test statistic (= 9.49 for 4 degrees-of-freedom at the 5-percent level of significance), thereby, inferring that the null hypothesis (mutual independence) can be rejected. Analysis of individual 2 by 2 contingency tables (based on Fisher's exact test) for these parameters shows that, while ascent duration is strongly related to maximum amplitude in the negative sense (inverse correlation) - the Waldmeier effect, it also is related (marginally) to period, but in the positive sense (direct correlation). No significant (or marginally significant) correlation is found between period and maximum amplitude. Using cycle 22 as a test case, we show that by the 12th month following conventional onset, cycle 22 appeared highly likely to be a fast-rising, larger-than-average-size cycle. Because of the inferred correlation between ascent duration and period, it also seems likely that it will have a period shorter than average length.

On Determining the Rise, Size, and Duration Classes of a Sunspot Cycle

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.; Reichmann, Edwin J.

1996-01-01

The behavior of ascent duration, maximum amplitude, and period for cycles 1 to 21 suggests that they are not mutually independent. Analysis of the resultant three-dimensional contingency table for cycles divided according to rise time (ascent duration), size (maximum amplitude), and duration (period) yields a chi-square statistic (= 18.59) that is larger than the test statistic (= 9.49 for 4 degrees-of-freedom at the 5-percent level of significance), thereby, inferring that the null hypothesis (mutual independence) can be rejected. Analysis of individual 2 by 2 contingency tables (based on Fisher's exact test) for these parameters shows that, while ascent duration is strongly related to maximum amplitude in the negative sense (inverse correlation) - the Waldmeier effect, it also is related (marginally) to period, but in the positive sense (direct correlation). No significant (or marginally significant) correlation is found between period and maximum amplitude. Using cycle 22 as a test case, we show that by the 12th month following conventional onset, cycle 22 appeared highly likely to be a fast-rising, larger-than-average-size cycle. Because of the inferred correlation between ascent duration and period, it also seems likely that it will have a period shorter than average length.

Standardized verification of fuel cycle modeling

DOE PAGES

Feng, B.; Dixon, B.; Sunny, E.; ...

2016-04-05

A nuclear fuel cycle systems modeling and code-to-code comparison effort was coordinated across multiple national laboratories to verify the tools needed to perform fuel cycle analyses of the transition from a once-through nuclear fuel cycle to a sustainable potential future fuel cycle. For this verification study, a simplified example transition scenario was developed to serve as a test case for the four systems codes involved (DYMOND, VISION, ORION, and MARKAL), each used by a different laboratory participant. In addition, all participants produced spreadsheet solutions for the test case to check all the mass flows and reactor/facility profiles on a year-by-yearmore » basis throughout the simulation period. The test case specifications describe a transition from the current US fleet of light water reactors to a future fleet of sodium-cooled fast reactors that continuously recycle transuranic elements as fuel. After several initial coordinated modeling and calculation attempts, it was revealed that most of the differences in code results were not due to different code algorithms or calculation approaches, but due to different interpretations of the input specifications among the analysts. Therefore, the specifications for the test case itself were iteratively updated to remove ambiguity and to help calibrate interpretations. In addition, a few corrections and modifications were made to the codes as well, which led to excellent agreement between all codes and spreadsheets for this test case. Although no fuel cycle transition analysis codes matched the spreadsheet results exactly, all remaining differences in the results were due to fundamental differences in code structure and/or were thoroughly explained. As a result, the specifications and example results are provided so that they can be used to verify additional codes in the future for such fuel cycle transition scenarios.« less

Vibration and Thermal Cycling Effects on Bulk-fill Insulation Materials for Cryogenic Tanks

NASA Astrophysics Data System (ADS)

Fesmire, J. E.; Augustynowicz, S. D.; Nagy, Z. F.; Sojourner, S. J.; Morris, D. L.

2006-04-01

Large-scale (1,000,000 liters or more) cryogenic storage tanks are typically perlite-insulated double-walled vessels. Associated problems with perlite, such as mechanical compaction and settling, could be greatly reduced by using newer bulk-fill materials such as glass bubbles or aerogel beads. Using the newer materials should translate to lower life cycle costs and improved system reliability. NASA Kennedy Space Center is leveraging its experience in the areas of materials development, insulation testing, and cryogenic systems design to develop an insulation retrofit option that will meet both industry and NASA requirements. A custom 10-liter dewar test apparatus, developed by the KSC Cryogenics Test Laboratory, was used to determine the vibration and thermal cycling effects on different bulk-fill insulation materials for cryogenic tanks. The testing included liquid-nitrogen boiloff testing and thermal cycling (with vibration) of a number of test dewars. Test results show that glass bubbles have better thermal performance and less mechanical compaction compared to perlite powder. The higher cost of the bulk material should be offset by reduced commodity loss from boiloff and improvements in material handling, evacuation, and vacuum retention. The long-term problem with settling and compaction of perlite should also be eliminated. Aerogel beads are superior for the no-vacuum condition and can now be considered in some applications. Further studies on large-scale systems are presently being pursued.

40 CFR 1065.512 - Duty cycle generation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Duty cycle generation. 1065.512... CONTROLS ENGINE-TESTING PROCEDURES Performing an Emission Test Over Specified Duty Cycles § 1065.512 Duty cycle generation. (a) Generate duty cycles according to this section if the standard-setting part...

Evaluation of multidensity orthotic materials used in footwear for patients with diabetes.

PubMed

Foto, J G; Birke, J A

1998-12-01

Selected combinations of multidensity orthotic materials were tested under simulated walking conditions found in the forefoot of diabetic patients. Materials were compared for therapeutic effectiveness by their stress/strain properties and dynamic compression set. Results showed that all of the multidensity materials experienced losses in performance throughout the testing period of 100,000 cycles, with the greatest losses occurring within the first 10,000 cycles. Of the materials tested, Poron + Plastazote #2 and Spenco + Microcel Puff Lite had the highest dynamic material strain and the lowest dynamic compression set over 100,000 cycles. In comparison, these are better multidensity combinations than the others tested to use as therapeutic orthoses in footwear for diabetic patients.

A Turbine Based Combined Cycle Engine Inlet Model and Mode Transition Simulation Based on HiTECC Tool

NASA Technical Reports Server (NTRS)

Csank, Jeffrey; Stueber, Thomas

2012-01-01

An inlet system is being tested to evaluate methodologies for a turbine based combined cycle propulsion system to perform a controlled inlet mode transition. Prior to wind tunnel based hardware testing of controlled mode transitions, simulation models are used to test, debug, and validate potential control algorithms. One candidate simulation package for this purpose is the High Mach Transient Engine Cycle Code (HiTECC). The HiTECC simulation package models the inlet system, propulsion systems, thermal energy, geometry, nozzle, and fuel systems. This paper discusses the modification and redesign of the simulation package and control system to represent the NASA large-scale inlet model for Combined Cycle Engine mode transition studies, mounted in NASA Glenn s 10-foot by 10-foot Supersonic Wind Tunnel. This model will be used for designing and testing candidate control algorithms before implementation.

A Turbine Based Combined Cycle Engine Inlet Model and Mode Transition Simulation Based on HiTECC Tool

NASA Technical Reports Server (NTRS)

Csank, Jeffrey T.; Stueber, Thomas J.

2012-01-01

An inlet system is being tested to evaluate methodologies for a turbine based combined cycle propulsion system to perform a controlled inlet mode transition. Prior to wind tunnel based hardware testing of controlled mode transitions, simulation models are used to test, debug, and validate potential control algorithms. One candidate simulation package for this purpose is the High Mach Transient Engine Cycle Code (HiTECC). The HiTECC simulation package models the inlet system, propulsion systems, thermal energy, geometry, nozzle, and fuel systems. This paper discusses the modification and redesign of the simulation package and control system to represent the NASA large-scale inlet model for Combined Cycle Engine mode transition studies, mounted in NASA Glenn s 10- by 10-Foot Supersonic Wind Tunnel. This model will be used for designing and testing candidate control algorithms before implementation.

Brayton cycle heat exchanger and duct assembly (HXDA, preliminary design and technology tests

NASA Technical Reports Server (NTRS)

Coombs, M. G.; Morse, C. J.; Graves, R. F.; Gibson, J. C.

1972-01-01

A preliminary design of the heat exchanger and duct assembly (HXDA) for a 60 kwe, closed loop, Brayton cycle space power system is presented. This system is weight optimized within the constraints imposed by the defined structural and operational requirements. Also presented are the results of several small scale tests, directed to obtaining specific design data and/or the resolution of a design approach for long life Brayton cycle heat exchanger systems.

Cycle life test and failure model of nickel-hydrogen cells

NASA Technical Reports Server (NTRS)

Smithrick, J. J.

1983-01-01

Six ampere hour individual pressure vessel nickel hydrogen cells were charge/discharge cycled to failure. Failure as used here is defined to occur when the end of discharge voltage degraded to 0.9 volts. They were cycled under a low earth orbit cycle regime to a deep depth of discharge (80 percent of rated ampere hour capacity). Both cell designs were fabricated by the same manufacturer and represent current state of the art. A failure model was advanced which suggests both cell designs have inadequate volume tolerance characteristics. The limited existing data base at a deep depth of discharge (DOD) was expanded. Two cells of each design were cycled. One COMSAT cell failed at cycle 1712 and the other failed at cycle 1875. For the Air Force/Hughes cells, one cell failed at cycle 2250 and the other failed at cycle 2638. All cells, of both designs, failed due to low end of discharge voltage (0.9 volts). No cell failed due to electrical shorts. After cell failure, three different reconditioning tests (deep discharge, physical reorientation, and open circuit voltage stand) were conducted on all cells of each design. A fourth reconditioning test (electrolyte addition) was conducted on one cell of each design. In addition post cycle cell teardown and failure analysis were performed on the one cell of each design which did not have electrolyte added after failure.

The effect of temperature cycling typical of low earth orbit satellites on thin films of YBa2Cu3O(7-x)

NASA Technical Reports Server (NTRS)

Mogro-Campero, A.; Turner, L. G.; Bogorad, A.; Herschitz, R.

1991-01-01

Thin films of YBa2Cu3O(7-x) (YBCO) were temperature cycled to simulate conditions of a low earth orbit satellite. In one series of tests, epitaxial and polycrystalline YBCO films were cycled between temperatures of +/- 80 C in vacuum and in nitrogen for hundreds of cycles. The room temperature resistance of an epitaxial YBCO film increased by about 10 percent, but the superconducting transition temperature was unchanged. The largest changes were for a polycrystalline YBCO film on oxidized silicon with a zirconia buffer layer, for which the transition temperature decreased by 3 K. An extended test was carried out for epitaxial films. After 3200 cycles (corresponding to about 230 days in space), transition temperatures and critical current densities remained unchanged.

Degradation of Teflon(trademark) FEP Following Charged Particle Radiation and Rapid Thermal Cycling

NASA Technical Reports Server (NTRS)

Townsend, Jacqueline; Powers, Charles; Viens, Michael; Ayres-Treusdell, Mary; Munoz, Bruno

1999-01-01

During the Second Servicing Mission (SM2) of the Hubble Space Telescope (HST) severe degradation was observed on the outer layer of the thermal control blankets. Astronaut observations and photographs revealed large cracks in the metallized Teflon(trademark) FEP (fluorinated ethylene propylene), the outer layer of the multi-layer insulation (MLI), in many locations around the telescope. In an effort to understand what elements of the space environment might cause such damage, pristine Teflon(trademark) FEP was tested for durability to radiation and thermal cycling. Specimens were subjected to electron and proton fluences comparable to those experienced by HST and were subsequently thermal cycled in a custom-built rapid thermal cycle chamber. Tensile tests of the specimens showed that radiation followed by thermal cycling significantly reduced the ultimate strength and elongation of Teflon(trademark) FEP.

Degradation of Teflon(tm) FEP Following Charged Particle Radiation and Rapid Thermal Cycling

NASA Technical Reports Server (NTRS)

Townsend, Jacqueline A.; Powers, Charles E.; Viens, Michael J.; Ayres-Treusdell, Mary T.; Munoz, Bruno

1998-01-01

During the Second Servicing Mission (SM2) of the Hubble Space Telescope (HST) severe degradation was observed on the outer layer of the thermal control blankets. Astronaut observations and photographs revealed large cracks in the metallized Teflon FEP (fluorinated ethylene propylene), the outer layer of the multi-layer insulation (MLI), in many locations around the telescope. In an effort to understand what elements of the space environment might cause such damage, pristine Teflon' FEP was tested for durability to radiation and thermal cycling. Specimens were subjected to electron and proton fluences comparable to those experienced by HST and were subsequently thermal cycled in a custom-built rapid thermal cycle chamber. Tensile tests of the specimens showed that radiation followed by thermal cycling significantly reduced the ultimate strength and elongation of Teflon FEP.

Degradation of Teflon(tm) FEP Following Charged Particle Radiation and Rapid Thermal Cycling

NASA Technical Reports Server (NTRS)

Townsend, Jacqueline A.; Powers, Charles E.; Viens, Michael J.; Ayres-Treusdell, Mary T.; Munoz, Bruno F.

1998-01-01

During the Second Servicing Mission (SM2) of the Hubble Space Telescope (HST) severe degradation was observed on the outer layer of the thermal control blankets. Astronaut observations and photographs revealed large cracks in the metallized Teflon' FEP (fluorinated ethylene propylene), the outer layer of the multi-layer insulation (MLI), in many locations around the telescope. In an effort to understand what elements of the space environment might cause such damage, pristine Teflon(registered trademark) FEP was tested for durability to radiation and thermal cycling. Specimens were subjected to electron and proton fluences comparable to those experienced by HST and were subsequently thermal cycled in a custom-built rapid thermal cycle chamber. Tensile tests of the specimens showed that radiation followed by thermal cycling significantly reduced the ultimate strength and elongation of Teflon(registered trademark) FEP.

Degradation of Teflon(tm) FEP Following Charged Particle Radiation and Rapid Thermal Cycling

NASA Technical Reports Server (NTRS)

Townsend, Jacqueline; Powers, Charles; Viens, Michael; Ayres-Treusdell, Mary; Munoz, Bruno

1998-01-01

During the Second Servicing Mission (SM2) of the Hubble Space Telescope (HST) severe degradation was observed on the outer layer of the thermal control blankets. Astronaut observations and photographs revealed large cracks in the metallized Teflon(R) FEP (fluorinated ethylene propylene), the outer layer of the multi-layer insulation (MLI), in many locations around the telescope. In an effort to understand what elements of the space environment might cause such damage, pristine Teflon(R) FEP was tested for durability to radiation and thermal cycling. Specimens were subjected to electron and proton fluences comparable to those experienced by HST and were subsequently thermal cycled in a custom-built rapid thermal cycle chamber. Tensile tests of the specimens showed that radiation followed by thermal cycling significantly reduced the ultimate strength and elongation of Teflon(R) FEP.

Female Hamster Preference for Odors is Not Regulated by Circulating Gonadal Hormones

PubMed Central

Eidson, Lori N.; Maras, Pamela M.; Epperson, Erin; Petrulis, Aras

2009-01-01

Proceptive and receptive behaviors of female rodents, such as golden hamsters, are often regulated by changes in circulating levels of ovarian hormones. However, less is known about how ovarian hormones might regulate female hamster’s attraction and preference for volatile odor from males. To evaluate this, we assessed female preference by recording investigation and proximity to male and female volatile odorants in a Y-maze across all days of the estrous cycle (Experiment 1 & 2) or following ovariectomy (Experiment 3). In Experiment 1, female subjects were tested four times, once on each day of their estrous cycle. Females showed a preference for male odors on diestrus day 1 and to a lesser degree on proestrus, but showed no preference on the day of behavioral estrus. Irrespective of cycle day, preference was apparent in the first few days of testing and disappeared by the fourth day, suggesting that repeated testing attenuated female preference. To avoid this problem, in Experiment 2 each animal was tested only on one day of the 4-day estrous cycle. Female preference for male volatile odors over those from females was observed on each day of their estrous cycle, including estrus. Moreover, following gonadectomy (Experiment 3) female hamsters still preferred male volatile odors to those of females. Taken together, this suggests that circulating levels of gonadal hormones do not influence preference for male volatile odors in female hamsters. PMID:17374544

A modern space simulation facility to accommodate high production acceptance testing

NASA Technical Reports Server (NTRS)

Glover, J. D.

1986-01-01

A space simulation laboratory that supports acceptance testing of spacecraft and associated subsystems at throughput rates as high as nine per year is discussed. The laboratory includes a computer operated 27' by 30' space simulation, a 20' by 20' by 20' thermal cycle chamber and an eight station thermal cycle/thermal vacuum test system. The design philosophy and unique features of each system are discussed. The development of operating procedures, test team requirements, test team integration, and other peripheral activation details are described. A discussion of special accommodations for the efficient utilization of the systems in support of high rate production is presented.

A comparative study of commercial lithium ion battery cycle life in electric vehicle: Capacity loss estimation

NASA Astrophysics Data System (ADS)

Han, Xuebing; Ouyang, Minggao; Lu, Languang; Li, Jianqiu

2014-12-01

Now the lithium ion batteries are widely used in electric vehicles (EV). The cycle life is among the most important characteristics of the power battery in EV. In this report, the battery cycle life experiment is designed according to the actual working condition in EV. Five different commercial lithium ion cells are cycled alternatively under 45 °C and 5 °C and the test results are compared. Based on the cycle life experiment results and the identified battery aging mechanism, the battery cycle life models are built and fitted by the genetic algorithm. The capacity loss follows a power law relation with the cycle times and an Arrhenius law relation with the temperature. For automotive application, to save the cost and the testing time, a battery SOH (state of health) estimation method combined the on-line model based capacity estimation and regular calibration is proposed.

Effect of Autoclave Cycles on Surface Characteristics of S-File Evaluated by Scanning Electron Microscopy.

PubMed

Razavian, Hamid; Iranmanesh, Pedram; Mojtahedi, Hamid; Nazeri, Rahman

2016-01-01

Presence of surface defects in endodontic instruments can lead to unwanted complications such as instrument fracture and incomplete preparation of the canal. The current study was conducted to evaluate the effect of autoclave cycles on surface characteristics of S-File by scanning electron microscopy (SEM). In this experimental study, 17 brand new S-Files (#30) were used. The surface characteristics of the files were examined in four steps (without autoclave, 1 autoclave cycle, 5 autoclave cycles and 10 autoclave cycles) by SEM under 200× and 1000× magnifications. Data were analyzed using the SPSS software and the paired sample t-test, independent sample t-test and multifactorial repeated measures ANOVA. The level of significance was set at 0.05. New files had debris and pitting on their surfaces. When the autoclave cycles were increased, the mean of surface roughness also increased at both magnifications (P<0.05). Moreover, under 1000× magnification the multifactorial repeated measures ANOVA showed more surface roughness (P<0.001). Sterilization by autoclave increased the surface roughness of the files and this had was directly related to the number of autoclave cycles.

Effect of Autoclave Cycles on Surface Characteristics of S-File Evaluated by Scanning Electron Microscopy

PubMed Central

Razavian, Hamid; Iranmanesh, Pedram; Mojtahedi, Hamid; Nazeri, Rahman

2016-01-01

Introduction: Presence of surface defects in endodontic instruments can lead to unwanted complications such as instrument fracture and incomplete preparation of the canal. The current study was conducted to evaluate the effect of autoclave cycles on surface characteristics of S-File by scanning electron microscopy (SEM). Methods and Materials: In this experimental study, 17 brand new S-Files (#30) were used. The surface characteristics of the files were examined in four steps (without autoclave, 1 autoclave cycle, 5 autoclave cycles and 10 autoclave cycles) by SEM under 200× and 1000× magnifications. Data were analyzed using the SPSS software and the paired sample t-test, independent sample t-test and multifactorial repeated measures ANOVA. The level of significance was set at 0.05. Results: New files had debris and pitting on their surfaces. When the autoclave cycles were increased, the mean of surface roughness also increased at both magnifications (P<0.05). Moreover, under 1000× magnification the multifactorial repeated measures ANOVA showed more surface roughness (P<0.001). Conclusion: Sterilization by autoclave increased the surface roughness of the files and this had was directly related to the number of autoclave cycles. PMID:26843874

Ultrastructural and histochemical study on the interrenal cells of the male stickleback (Gasterosteus aculeatus, Teleostea), in relation to the reproductive annual cycle

PubMed Central

CIVININI, ANNALENA; PADULA, DANIELA; GALLO, VALENTINA P.

2001-01-01

The steroidogenic interrenal cells in the adrenal homologue of the male stickleback (Gasterosteus aculeatus) were studied in relation to the reproductive cycle by means of histological and ultrastructural observations, and using histochemical methods for the localisation of 3β-hydroxysteroid dehydrogenase (3βHSD) and 17β-hydroxysteroid dehydrogenase (17βHSD). To determine the various stages of the reproductive cycle, the testes were also examined by histological and histochemical methods (3βHSD). The results indicate that in this teleost the interrenal cells can undergo a cycle in which phases characterised by different cytological aspects are observed. During this cycle there is a renewal of organelles, in particular mitochondria and SER. Periodic degenerative processes are also found. Organelle cytology showed that the cell cycle has at least 3 different aspects during the year. An analogy with some cytological aspects of the adrenal zonation in mammals is possible. It is postulated that the interrenal gland activity could substitute or supplement androgen production by the testes. PMID:11554507

Virtex-5 CN Package Daisy Chain Evaluation Test Report

NASA Technical Reports Server (NTRS)

Suh, Jong-ook

2016-01-01

The board-level temperature cycling reliability of Xilinx Virtex-5 (V5) CN package was investigated. V5s were temperature cycled under two conditions, 0 to +100 C (0/100) and -55 to +100 C (-55/100). During the 0/100 test, no part out of 8 parts failed up to 6586 cycles. During the -55/100 test, one part out of 8 parts failed at 1236 cycle, and there were no additional failures up to 1705 cycles. The failure mode of the part that failed at 1236 cycles indicated that most likely the failure was not a solder fatigue failure, and therefore no obvious solder fatigue failure was observed throughout the tests.

Influence of driving cycles on unit emissions from passenger cars

NASA Astrophysics Data System (ADS)

Joumard, R.; André, M.; Vidon, R.; Tassel, P.; Pruvost, C.

Small samples of petrol engine or diesel cars, equipped with or without catalysts, were tested over 36 driving cycles divided into four categories - standard cycles and three sets of cycles more representative of real-world driving conditions. The tests addressed standard gaseous pollutants and fuel consumption and also less frequently measured pollutant such as CH 4. In the first part of this paper we examine cold emissions in order to assess the duration of the cold start impact and the representativity of the cold ECE15 cycle. Then unit emissions are compared over the four driving cycle families. As compared to representative cycles, the standardised cycles underestimate hot emissions by almost 50% for petrol engine cars and 30% for diesel vehicles. Conversely, the results obtained for the three representative cycle families are in relatively close agreement with each other - within approximately 10%. However, the cinematic properties of the three families differ. Finally, we demonstrate that weighting all emission data equally, not taking into account the weight of each cycle in overall traffic, introduces significant biases, particularly when plotting emission vs. average speed curves.

The Comparative Effects of Prediction/Discussion-Based Learning Cycle, Conceptual Change Text, and Traditional Instructions on Student Understanding of Genetics

NASA Astrophysics Data System (ADS)

Yilmaz, Diba; Tekkaya, Ceren; Sungur, Semra

2011-03-01

The present study examined the comparative effects of a prediction/discussion-based learning cycle, conceptual change text (CCT), and traditional instructions on students' understanding of genetics concepts. A quasi-experimental research design of the pre-test-post-test non-equivalent control group was adopted. The three intact classes, taught by the same science teacher, were randomly assigned as prediction/discussion-based learning cycle class (N = 30), CCT class (N = 25), and traditional class (N = 26). Participants completed the genetics concept test as pre-test, post-test, and delayed post-test to examine the effects of instructional strategies on their genetics understanding and retention. While the dependent variable of this study was students' understanding of genetics, the independent variables were time (Time 1, Time 2, and Time 3) and mode of instruction. The mixed between-within subjects analysis of variance revealed that students in both prediction/discussion-based learning cycle and CCT groups understood the genetics concepts and retained their knowledge significantly better than students in the traditional instruction group.

Influence of Rapid Freeze-Thaw Cycling on the Mechanical Properties of Sustainable Strain-Hardening Cement Composite (2SHCC)

PubMed Central

Jang, Seok-Joon; Rokugo, Keitetsu; Park, Wan-Shin; Yun, Hyun-Do

2014-01-01

This paper provides experimental results to investigate the mechanical properties of sustainable strain-hardening cement composite (2SHCC) for infrastructures after freeze-thaw actions. To improve the sustainability of SHCC materials in this study, high energy-consumptive components—silica sand, cement, and polyvinyl alcohol (PVA) fibers—in the conventional SHCC materials are partially replaced with recycled materials such as recycled sand, fly ash, and polyethylene terephthalate (PET) fibers, respectively. To investigate the mechanical properties of green SHCC that contains recycled materials, the cement, PVA fiber and silica sand were replaced with 10% fly ash, 25% PET fiber, and 10% recycled aggregate based on preliminary experimental results for the development of 2SHCC material, respectively. The dynamic modulus of elasticity and weight for 2SHCC material were measured at every 30 cycles of freeze-thaw. The effects of freeze-thaw cycles on the mechanical properties of sustainable SHCC are evaluated by conducting compressive tests, four-point flexural tests, direct tensile tests and prism splitting tests after 90, 180, and 300 cycles of rapid freeze-thaw. Freeze-thaw testing was conducted according to ASTM C 666 Procedure A. Test results show that after 300 cycles of freezing and thawing actions, the dynamic modulus of elasticity and mass loss of damaged 2SHCC were similar to those of virgin 2SHCC, while the freeze-thaw cycles influence mechanical properties of the 2SHCC material except for compressive behavior. PMID:28788522

Laser thermal shock and fatigue testing system

NASA Astrophysics Data System (ADS)

Fantini, Vincenzo; Serri, Laura; Bianchi, P.

1997-08-01

Thermal fatigue consists in repeatedly cycling the temperature of a specimen under test without any other constraint and stopping the test when predefined damage aspects. The result is a lifetime in terms of number of cycles. The parameters of the thermal cycle are the following: minimum and maximum temperature, time of heating, of cooling and time at high or at low temperature. When the temperature jump is very big and fast, phenomena of thermal shock can be induced. Among the numerous techniques used to perform these tests, the laser thermal fatigue cycling is very effective when fast heating of small and localized zones is required. That's the case of test performed to compare new and repaired blades of turbogas machines or components of combustion chambers of energy power plants. In order to perform these tests a thermal fatigue system, based on 1 kW Nd-YAG laser as source of heating, has been developed. The diameter of the heated zone of the specimen irradiated by the laser is in the range 0.5 - 20 mm. The temperatures can be chosen between 200 degree(s)C and 1500 degree(s)C and the piece can be maintained at high and/or low temperature from 0 s to 300 s. Temperature are measured by two sensors: a pyrometer for the high range (550 - 1500 degree(s)C) and a contactless thermocouple for the low range (200 - 550 degree(s)C). Two different gases can be blown on the specimen in the irradiated spot or in sample backside to speed up cooling phase. A PC-based control unit with a specially developed software performs PID control of the temperature cycle by fast laser power modulation. A high resolution vision system of suitable magnification is connected to the control unit to detect surface damages on the specimen, allowing real time monitoring of the tested zone as well as recording and reviewing the images of the sample during the test. Preliminary thermal fatigue tests on flat specimens of INCONEL 738 and HAYNES 230 are presented. IN738 samples, laser cladded by powder of the same material to simulate the refurbishing of a damaged turbine blade after long-term operation, are compared to the parents. Lifetimes are decreasing when high temperature of the cycle is increased and shorter lifetimes of repaired pieces have been found. Laser and TIG welding on HY230 specimens are compared to the parent. Parent and repaired samples have no evidence of cracks after 1500 thermal cycles between 650 and 1000 degree(s)C.

Extended Pulse-Powered Humidity-Freeze Cycling for Testing Module-Level Power Electronics

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

Hacke, Peter L; Rodriguez, Miguel; Kempe, Michael D

An EMI suppression capacitor (polypropylene film type) failed by 'popcorning' due to vapor outgassing in pulse powered humidity-freeze cycles. No shorts or shunts could be detected despite mildly corroded metallization visible in the failed capacitor. Humidity-freeze cycling is optimized to break into moisture barriers. However, further studies will be required on additional module level power electronic (MLPE) devices to optimize the stress testing for condensation to precipitate any weakness to short circuiting and other humidity/bias failure modes.

The effects of engine operating conditions on CCD chemistry and morphology

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

Yeh, S.W.; Moore, S.M.; Sabourin, E.T.

1996-10-01

The effects of engine driving cycle and engine coolant temperature on combustion chamber deposit (CCD) surface chemistry and morphology were assessed by the use of XPS and scanning electron micrographs. A 3.1L V6 test cell engine was used to generate a six test matrix that compared deposit surface chemistry and morphology under two distinctly different driving cycles, each cycle being evaluated at three separate engine coolant temperatures. Deposit material for each respective test was collected by removable combustion chamber sample probes that were subjected to XPS surface analysis and SEM evaluation. Discernible trends were observed in surface chemistry and depositmore » amounts with respect to changes in both driving cycle and coolant temperature. However, much more pronounced were deposit morphological changes recorded by SEM in different engine coolant temperature regimes for both of the utilized driving cycles. Deposit nodules formed in one temperature regime were seen to be typically much larger in size, highly irregular in shape, and appeared to be porous in structure. At a different operating temperature, the deposit nodules were observed to be extremely uniform and more tightly packed.« less

Thermal cycle testing of Space Station Freedom solar array blanket coupons

NASA Technical Reports Server (NTRS)

Scheiman, David A.; Schieman, David A.

1991-01-01

Lewis Research Center is presently conducting thermal cycle testing of solar array blanket coupons that represent the baseline design for Space Station Freedom. Four coupons were fabricated as part of the Photovoltaic Array Environment Protection (PAEP) Program, NAS 3-25079, at Lockheed Missile and Space Company. The objective of the testing is to demonstrate the durability or operational lifetime of the solar array welded interconnect design within the durability or operational lifetime of the solar array welded interconnect design within a low earth orbit (LEO) thermal cycling environment. Secondary objectives include the observation and identification of potential failure modes and effects that may occur within the solar array blanket coupons as a result of thermal cycling. The objectives, test articles, test chamber, performance evaluation, test requirements, and test results are presented for the successful completion of 60,000 thermal cycles.

Hubble Space telescope thermal cycle test report for large solar array samples with BSFR cells (Sample numbers 703 and 704)

NASA Technical Reports Server (NTRS)

Alexander, D. W.

1992-01-01

The Hubble space telescope (HST) solar array was designed to meet specific output power requirements after 2 years in low-Earth orbit, and to remain operational for 5 years. The array, therefore, had to withstand 30,000 thermal cycles between approximately +100 and -100 C. The ability of the array to meet this requirement was evaluated by thermal cycle testing, in vacuum, two 128-cell solar cell modules that exactly duplicated the flight HST solar array design. Also, the ability of the flight array to survive an emergency deployment during the dark (cold) portion of an orbit was evaluated by performing a cold-roll test using one module.

Hubble Space Telescope solar cell module thermal cycle test

NASA Technical Reports Server (NTRS)

Douglas, Alexander; Edge, Ted; Willowby, Douglas; Gerlach, Lothar

1992-01-01

The Hubble Space Telescope (HST) solar array consists of two identical double roll-out wings designed after the Hughes flexible roll-up solar array (FRUSA) and was developed by the European Space Agency (ESA) to meet specified HST power output requirements at the end of 2 years, with a functional lifetime of 5 years. The requirement that the HST solar array remain functional both mechanically and electrically during its 5-year lifetime meant that the array must withstand 30,000 low Earth orbit (LEO) thermal cycles between approximately +100 and -100 C. In order to evaluate the ability of the array to meet this requirement, an accelerated thermal cycle test in vacuum was conducted at NASA's Marshall Space Flight Center (MSFC), using two 128-cell solar array modules which duplicated the flight HST solar array. Several other tests were performed on the modules. The thermal cycle test was interrupted after 2,577 cycles, and a 'cold-roll' test was performed on one of the modules in order to evaluate the ability of the flight array to survive an emergency deployment during the dark (cold) portion of an orbit. A posttest static shadow test was performed on one of the modules in order to analyze temperature gradients across the module. Finally, current in-flight electrical performance data from the actual HST flight solar array will be tested.

Fatigue Crack Growth Behavior Evaluation of Grainex Mar-M 247 for NASA's High Temperature, High Speed Turbine Seal Test Rig

NASA Technical Reports Server (NTRS)

Delgado, Irebert R.; Steinetz, Bruce M.; Rimnac, Clare M.; Lewandowski, John J.

2008-01-01

The fatigue crack growth behavior of Grainex Mar-M 247 is evaluated for NASA s Turbine Seal Test Facility. The facility is used to test air-to-air seals primarily for use in advanced jet engine applications. Because of extreme seal test conditions of temperature, pressure, and surface speeds, surface cracks may develop over time in the disk bolt holes. An inspection interval is developed to preclude catastrophic disk failure by using experimental fatigue crack growth data. By combining current fatigue crack growth results with previous fatigue strain-life experimental work, an inspection interval is determined for the test disk. The fatigue crack growth life of the NASA disk bolt holes is found to be 367 cycles at a crack depth of 0.501 mm using a factor of 2 on life at maximum operating conditions. Combining this result with previous fatigue strain-life experimental work gives a total fatigue life of 1032 cycles at a crack depth of 0.501 mm. Eddy-current inspections are suggested starting at 665 cycles since eddy current detection thresholds are currently at 0.381 mm. Inspection intervals are recommended every 50 cycles when operated at maximum operating conditions.

Modeling Heavy/Medium-Duty Fuel Consumption Based on Drive Cycle Properties

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

Wang, Lijuan; Duran, Adam; Gonder, Jeffrey

This paper presents multiple methods for predicting heavy/medium-duty vehicle fuel consumption based on driving cycle information. A polynomial model, a black box artificial neural net model, a polynomial neural network model, and a multivariate adaptive regression splines (MARS) model were developed and verified using data collected from chassis testing performed on a parcel delivery diesel truck operating over the Heavy Heavy-Duty Diesel Truck (HHDDT), City Suburban Heavy Vehicle Cycle (CSHVC), New York Composite Cycle (NYCC), and hydraulic hybrid vehicle (HHV) drive cycles. Each model was trained using one of four drive cycles as a training cycle and the other threemore » as testing cycles. By comparing the training and testing results, a representative training cycle was chosen and used to further tune each method. HHDDT as the training cycle gave the best predictive results, because HHDDT contains a variety of drive characteristics, such as high speed, acceleration, idling, and deceleration. Among the four model approaches, MARS gave the best predictive performance, with an average absolute percent error of -1.84% over the four chassis dynamometer drive cycles. To further evaluate the accuracy of the predictive models, the approaches were first applied to real-world data. MARS outperformed the other three approaches, providing an average absolute percent error of -2.2% of four real-world road segments. The MARS model performance was then compared to HHDDT, CSHVC, NYCC, and HHV drive cycles with the performance from Future Automotive System Technology Simulator (FASTSim). The results indicated that the MARS method achieved a comparative predictive performance with FASTSim.« less

Varenicline impairs extinction and enhances reinstatement across repeated cycles of nicotine self-administration in rats.

PubMed

Macnamara, Claire L; Holmes, Nathan M; Westbrook, R Fred; Clemens, Kelly J

2016-06-01

Varenicline is a partial nicotine receptor agonist widely prescribed as a smoking cessation medication. Repeated (or long-term) use of varenicline has been proposed as a treatment option for tobacco addiction. However the effect of repeated varenicline use on motivation for nicotine is unknown. Here the intravenous nicotine self-administration paradigm in rats was used to model the consequences of varenicline treatment across repeated cycles of administration, extinction and reinstatement. Rats acquired nicotine self-administration across 20 days before undergoing 6 days of extinction, where each extinction session was preceded by a single injection of varenicline or saline. This was followed by a single varenicline-free nicotine-primed reinstatement test. All rats then reacquired nicotine self-administration for 10 days followed by a second cycle of extinction. Across this period, rats either received a second cycle of varenicline (VAR-VAR) or saline (SAL-SAL), or the alternative treatment (SAL-VAR, VAR-SAL), followed by a final reinstatement test. Treatment with varenicline increased responding across the first cycle of extinction, but did not affect responding in the reinstatement test. Across the second cycle, varenicline again increased responding across extinction, and critically, rats treated with varenicline across cycle 1 and saline across cycle 2 (Group VAR-SAL) exhibited more reinstatement than rats in any other group. The effect of VAR on nicotine seeking was not due to its effects on locomotor activity. Instead, the results suggest that a history of VAR can increase vulnerability to reinstatement/relapse when its treatment is discontinued. The possible mechanisms of this increased vulnerability are discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

40 CFR 86.1363-2007 - Steady-state testing with a discrete-mode cycle.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Steady-state testing with a discrete-mode cycle. 86.1363-2007 Section 86.1363-2007 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Exhaust Test Procedures § 86.1363-2007 Steady-state testing with a discrete-mode cycle. This section...

Bypass control valve seal and bearing life cycle test report

NASA Technical Reports Server (NTRS)

Lundback, A. V.

1972-01-01

The operating characteristics of a bypass control valve seal and bearing life cycle tests are reported. Data from the initial assembly, leak, torque, and deflection tests are included along with the cycle life test results and conclusions. The equipment involved was to be used in the nuclear engine for the rocket vehicles program.

Performance of Li-Ion Cells Under Battery Voltage Charge Control

NASA Technical Reports Server (NTRS)

Rao, Gopalakrishna M.; Vaidyanathan, Hari; Day, John H. (Technical Monitor)

2001-01-01

A study consisting of electrochemical characterization and Low-Earth-Orbit (LEO) cycling of Li-Ion cells from three vendors was initiated in 1999 to determine the cycling performance and to infuse the new technology in the future NASA missions. The 8-cell batteries included in this evaluation are prismatic cells manufactured by Mine Safety Appliances Company (MSA), cylindrical cells manufactured by SAFT and prismatic cells manufactured by Yardney Technical Products, Inc. (YTP). The three batteries were cycle tested in the LEO regime at 40% depth of discharge, and under a charge control technique that consists of battery voltage clamp with a current taper. The initial testing was conducted at 20 C; however, the batteries were cycled also intermittently at low temperatures. YTP 20 Ah cells consisted of mixed-oxide (Co and Ni) positive, graphitic carbon negative, LIPF6 salt mixed with organic carbonate solvents. The battery voltage clamp was 32 V. The low temperature cycling tests started after 4575 cycles at 20 C. The cells were not capable of cycling. at low temperature since the charge acceptance at battery level was poor. There was a cell in the battery that showed too high an end-of-charge (EOC) voltage thereby limiting the ability to charge the rest of the cells in the battery. The battery has completed 6714 cycles. SAFT 12 Ah cells consisted of mixed-oxide (Co and NO positive, graphitic carbon negative, LiPF6 salt mixed with organic carbonate solvents. The battery voltage clamp was for 30.8 V. The low temperature cycling tests started after 4594 cycles at 20 C. A cell that showed low end of discharge (EOD) and EOC voltages and three other cells that showed higher EOC voltages limited the charge acceptance at the selected voltage limit during charge. The cells were capable of cycling at 10 C and 0 C but the charge voltage limit had to be increased to 34.3 V (4.3 V per cell). The low temperature cycling may have induced poor chargeability since the voltage had to be increased to achieve the required charge input. The battery has completed 6226 cycles. MSA 10 Ah cells consisted of Co oxide positive, graphitic carbon negative, LiPF6 salt mixed with organic carbonate solvents. The battery voltage clamp was 30.8 V. The low temperature cycling tests were started after 2182 cycles at 20 C. The cells were capable of cycling at 10 C and 0 C. Like SAFT, the voltage limit on charge had to be increased to 36 V (4.5 V per cell). There was a cell (cell S/N 13) in the battery that showed poor performance features such as low EOD voltage and high EOC voltage. The battery has completed 3441 cycles. A reconditioning procedure that consisted of C15 charge to a taper current of C/100 and C/20 discharge improved the voltage behavior of SAFT and MSA cells with no significant effect on YTP cells. We have demonstrated that the charge operation with VT clamp at battery rather than at cell level is feasible for onboard Li-Ion battery operation.

Fluctuation in Spatial Ability Scores during the Menstrual Cycle.

ERIC Educational Resources Information Center

Moody, M. Suzanne

Whether or not fluctuations in spatial ability as measured by S. G. Vandenberg's Mental Rotations Test occur during the menstrual cycle was studied with 133 female students from 9 undergraduate educational psychology and nursing classes. For comparison, 28 male students also took the test. Scores from 55 females fell into the relevant menstrual…

Effect of thermal cycling on composites reinforced with two differently sized silica-glass fibers.

PubMed

Meriç, Gökçe; Ruyter, I Eystein

2007-09-01

To evaluate the effects of thermal cycling on the flexural properties of composites reinforced with two differently sized fibers. Acid-washed, woven, fused silica-glass fibers, were heat-treated at 500 degrees C, silanized and sized with one of two sizing resins (linear poly(butyl methacrylate)) (PBMA), cross-linked poly(methyl methacrylate) (PMMA). Subsequently the fibers were incorporated into a polymer matrix. Two test groups with fibers and one control group without fibers were prepared. The flexural properties of the composite reinforced with linear PBMA-sized fibers were evaluated by 3-point bend testing before thermal cycling. The specimens from all three groups were thermally cycled in water (12,000 cycles, 5/55 degrees C, dwell time 30 s), and afterwards tested by 3-point bending. SEM micrographs were taken of the fibers and of the fractured fiber reinforced composites (FRC). The reduction of ultimate flexural strength after thermal cycling was less than 20% of that prior to thermal cycling for composites reinforced with linear PBMA-sized silica-glass fibers. The flexural strength of the composite reinforced with cross-linked PMMA-sized fibers was reduced to less than half of the initial value. This study demonstrated that thermal cycling differently influences the flexural properties of composites reinforced with different sized silica-glass fibers. The interfacial linear PBMA-sizing polymer acts as a stress-bearing component for the high interfacial stresses during thermal cycling due to the flexible structure of the linear PBMA above Tg. The cross-linked PMMA-sizing, however, acts as a rigid component and therefore causes adhesive fracture between the fibers and matrix after the fatigue process of thermal cycling and flexural fracture.

Criterion validation of two submaximal aerobic fitness tests, the self-monitoring Fox-walk test and the Åstrand cycle test in people with rheumatoid arthritis.

PubMed

Nordgren, Birgitta; Fridén, Cecilia; Jansson, Eva; Österlund, Ted; Grooten, Wilhelmus Johannes; Opava, Christina H; Rickenlund, Anette

2014-09-17

Aerobic capacity tests are important to evaluate exercise programs and to encourage individuals to have a physically active lifestyle. Submaximal tests, if proven valid and reliable could be used for estimation of maximal oxygen uptake (VO2max). The purpose of the study was to examine the criterion-validity of the submaximal self-monitoring Fox-walk test and the submaximal Åstrand cycle test against a maximal cycle test in people with rheumatoid arthritis (RA). A secondary aim was to study the influence of different formulas for age predicted maximal heart rate when estimating VO2max by the Åstrand test. Twenty seven subjects (81% female), mean (SD) age 62 (8.1) years, diagnosed with RA since 17.9 (11.7) years, participated in the study. They performed the Fox-walk test (775 meters), the Åstrand test and the maximal cycle test (measured VO2max test). Pearson's correlation coefficients were calculated to determine the direction and strength of the association between the tests, and paired t-tests were used to test potential differences between the tests. Bland and Altman methods were used to assess whether there was any systematic disagreement between the submaximal tests and the maximal test. The correlation between the estimated and measured VO2max values were strong and ranged between r = 0.52 and r = 0.82 including the use of different formulas for age predicted maximal heart rate, when estimating VO2max by the Åstrand test. VO2max was overestimated by 30% by the Fox-walk test and underestimated by 10% by the Åstrand test corrected for age. When the different formulas for age predicted maximal heart rate were used, the results showed that two formulas better predicted maximal heart rate and consequently a more precise estimation of VO2max. Despite the fact that the Fox-walk test overestimated VO2max substantially, the test is a promising method for self-monitoring VO2max and further development of the test is encouraged. The Åstrand test should be considered as highly valid and feasible and the two newly developed formulas for predicting maximal heart rate according to age are preferable to use when estimating VO2max by the Åstrand test.

Evaluation of staff performance and interpretation of the screening program for prevention of thalassemia.

PubMed

Prommetta, Simaporn; Sanchaisuriya, Kanokwan; Fucharoen, Goonnapa; Yamsri, Supawadee; Chaiboonroeng, Attawut; Fucharoen, Supan

2017-06-15

Thalassemia screening program has been implemented for years in Southeast Asia, but no external quality assessment program has been established. We have developed and initiated the proficiency testing (PT) program for the first time in Thailand with the aim to assess the screening performance of laboratory staff and their competency in interpretation of the screening results. Three PT cycles per year were organized. From the first to the third cycle of the PT scheme, a total number of participant laboratories increased from 59 to 67. In each cycle, 2 PT items (assigned as blood samples of the couple) were provided. Performance evaluation was based on the accuracy of screening results, i.e . mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and the dichlorophenolindophenol (DCIP) test for haemoglobin E, including the competency in interpretation of screening results and assessment of foetal risk. Performance was assessed by comparing the participants' result against the assigned value. Of all 3 cycles, most laboratories reported acceptable MCV and MCH values. From the first to the third cycle, incorrect DCIP test and misinterpretation rates were decreased while incorrect risk assessment varied by cycle to cycle. Combining the accuracy of thalassemia screening and the competency in interpretation and risk assessment, approximately half of participants showed excellent performance. Improved performance observed in many laboratories reflects the achievement and benefit of the PT program which should be regularly provided.

Mir Cooperative Solar Array Project Accelerated Life Thermal Cycling Test

NASA Technical Reports Server (NTRS)

Hoffman, David J.; Scheiman, David A.

1996-01-01

The Mir Cooperative Solar Array (MCSA) project was a joint U.S./Russian effort to build a photovoltaic (PV) solar array and deliver it to the Russian space station Mir. The MCSA will be used to increase the electrical power on Mir and provide PV array performance data in support of Phase 1 of the International Space Station. The MCSA was brought to Mir by space shuttle Atlantis in November 1995. This report describes an accelerated thermal life cycle test which was performed on two samples of the MCSA. In eight months time, two MCSA solar array 'mini' panel test articles were simultaneously put through 24,000 thermal cycles. There was no significant degradation in the structural integrity of the test articles and no electrical degradation, not including one cell damaged early and removed from consideration. The nature of the performance degradation caused by this one cell is briefly discussed. As a result of this test, changes were made to improve some aspects of the solar cell coupon-to-support frame interface on the flight unit. It was concluded from the results that the integration of the U.S. solar cell modules with the Russian support structure would be able to withstand at least 24,000 thermal cycles (4 years on-orbit). This was considered a successful development test.

Study of the damage evolution function of tin silver copper in cycling

NASA Astrophysics Data System (ADS)

Qasaimeh, Awni

The present research focused on the assessment of solder joint fatigue life in microelectronics assemblies. A general concern of any reliability engineer is whether accelerated tests are relevant to field conditions. The risk of this was minimized by developing an approach to reduce the duration of an accelerated thermal cycling test, thus allowing for the use of less accelerated test conditions. For this purpose the conventional dye and pry technique was improved and used together with artificial neural networks to measure and characterize very early stages of crack growth. The same work also demonstrated a quantitative link between thermal cycling induced recrystallization and a strong acceleration of the subsequent fatigue crack growth and failure. A new study was conducted in which different combinations of annealing and isothermal cycling provided a systematic characterization of the effects of a range of individual parameters on the recrystallization. Experiments showed the ongoing coarsening of secondary precipitates to have a clear effect on recrystallization. The rate of recrystallization was also shown not to scale with the inelastic energy deposition. This means that the most popular current thermal cycling model cannot apply to SnAgCu solder joints. Recrystallization of the Sn grains is usually not the rate limiting mechanism in isothermal cycling. The crack initiation stage often takes up a much greater fraction of the overall life, and the eventual failure of BGA joints tends to involve transgranular crack growth instead. Cycling of individual solder joints allowed for monitoring of the evolution of the solder properties and the rate of inelastic energy deposition. Both the number of cycles to crack initiation and the subsequent number of cycles to failure were shown to be determined by the inelastic energy deposition. This provides for a simple model for the extrapolation of accelerated test results to the much milder cycling amplitudes characteristic of long term service conditions based on conventional Finite Element Modeling. It also offers a critical basis for the ongoing development of a practical model to account for the often dramatic break-down of Miner's rule of linear damage accumulation under variable cycling amplitudes as expected in realistic applications.

Understanding the meaning of lactate threshold in resistance exercises.

PubMed

Garnacho-Castaño, M V; Dominguez, R; Maté-Muñoz, J L

2015-05-01

This study compares acute cardiorespiratory, metabolic, mechanical and rating of perceived effort (RPE) responses to 2 different prolonged constant-load exercises, half-squat (HS) and cycle ergometry, performed at a workload corresponding to the lactate threshold (LT). A total of 18 healthy subjects completed 5 exercise tests separated by 48 h rest periods: an incremental cycle ergometer test, a constant-load cycle ergometer test at LT intensity, a one-repetition maximum (1RM) HS test, an incremental HS test and a constant-load HS test at LT intensity. In both constant-load tests, cardiorespiratory, metabolic and RPE data were recorded. Mechanical responses before and after each test were assessed in terms of jump height and mean power measured in a counter movement jump (CMJ) test. In both exercises, cardiorespiratory and metabolic responses stabilized, though cardiorespiratory responses were significantly greater for cycle ergometry (P<0.001), with the exception of respiratory exchange ratio (RER), which was higher for HS (P=0.028). Mechanical fatigue was observed in only HS (P<0.001). In conclusion, different exercise modalities induced different yet stable acute cardiorespiratory and metabolic responses. Although such responses were significantly reduced in HS, greater mechanical fatigue was produced, most likely because of the particular muscle actions involved in this form of exercise. © Georg Thieme Verlag KG Stuttgart · New York.

Failures in Hybrid Microcircuits During Environmental Testing. History Cases

NASA Technical Reports Server (NTRS)

Teverovsky, Alexander

2008-01-01

This purpose of this viewgraph presentation is to discuss failures in hermetic hybrids observed at the GSFC PA Lab during environmental stress testing. The cases discussed are: Case I. Substrate metallization failures during Thermal cycling (TC). Case II. Flex lid-induced failure. Case Ill. Hermeticity failures during TC. Case IV. Die metallization cracking during TC. and how many test cycles and parts is necessary? Case V. Wire Bond failures after life test. Case VI. Failures caused by Au/In IMC growth.

Experimental evaluation of the Battelle accelerated test design for the solar array at Mead, Nebraska

NASA Technical Reports Server (NTRS)

Frickland, P. O.; Repar, J.

1982-01-01

A previously developed test design for accelerated aging of photovoltaic modules was experimentally evaluated. The studies included a review of relevant field experience, environmental chamber cycling of full size modules, and electrical and physical evaluation of the effects of accelerated aging during and after the tests. The test results indicated that thermally induced fatigue of the interconnects was the primary mode of module failure as measured by normalized power output. No chemical change in the silicone encapsulant was detectable after 360 test cycles.

Power-Generation Characteristics After Vibration and Thermal Stresses of Thermoelectric Unicouples with CoSb3/Ti/Mo(Cu) Interfaces

NASA Astrophysics Data System (ADS)

Bae, Kwang Ho; Choi, Soon-Mok; Kim, Kyung-Hun; Choi, Hyoung-Seuk; Seo, Won-Seon; Kim, Il-Ho; Lee, Soonil; Hwang, Hae Jin

2015-06-01

Reliability tests for thermoelectric unicouples were carried out to investigate the adhesion properties of CoSb3/Ti/Mo(Cu) interfaces. The n-type In0.25 Co3.95Ni0.05Sb12 and p-type In0.25Co3FeSb12 bulks were prepared for fabricating a thermoelectric unicouple (one p- n couple) by an induction melting and a spark plasma sintering process. Mo-Cu alloy was selected as an electrode for the unicouples due to its high melting temperature and proper work function value. Many thermoelectric unicouples with the CoSb3/Ti/Mo(Cu) interfaces were fabricated with the proper brazing materials by means of a repeated firing process. Reliability of the unicouples with the interfaces was evaluated by a vibration test and a thermal cycling test. After the thermal cycling and vibration tests, the power-generation characteristics of the unicouples were compared with the unicouples before the tests. Even after the vibration test, electrical power with a power density of 0.5 W/cm2 was generated. The Ti-interlayer is considered as a possible candidate for making a reliable unicouple with high adhesion strength. With the thermal cycling test, the resistance of the unicouple increased and the electrical power from the unicouple decreased. A failure mode by the thermal cycling test was ascribed to a complex effect of micro-cracks originated from the thermal stress and oxidation problem of the thermoelectric materials; that is, a thick oxide layer more than 300 μm was detected after a high-temperature durability test of n-type In0.25Co3.95Ni0.05Sb12 material at 773 K in air for 7 days.

Closed Cycle Engine Program Used in Solar Dynamic Power Testing Effort

NASA Technical Reports Server (NTRS)

Ensworth, Clint B., III; McKissock, David B.

1998-01-01

NASA Lewis Research Center is testing the world's first integrated solar dynamic power system in a simulated space environment. This system converts solar thermal energy into electrical energy by using a closed-cycle gas turbine and alternator. A NASA-developed analysis code called the Closed Cycle Engine Program (CCEP) has been used for both pretest predictions and post-test analysis of system performance. The solar dynamic power system has a reflective concentrator that focuses solar thermal energy into a cavity receiver. The receiver is a heat exchanger that transfers the thermal power to a working fluid, an inert gas mixture of helium and xenon. The receiver also uses a phase-change material to store the thermal energy so that the system can continue producing power when there is no solar input power, such as when an Earth-orbiting satellite is in eclipse. The system uses a recuperated closed Brayton cycle to convert thermal power to mechanical power. Heated gas from the receiver expands through a turbine that turns an alternator and a compressor. The system also includes a gas cooler and a radiator, which reject waste cycle heat, and a recuperator, a gas-to-gas heat exchanger that improves cycle efficiency by recovering thermal energy.

Experimental and theoretical investigation of fatigue life in reusable rocket thrust chambers

NASA Technical Reports Server (NTRS)

Hannum, N. P.; Kasper, H. J.; Pavli, A. J.

1976-01-01

During a test program to investigate low-cycle thermal fatigue, 13 rocket combustion chambers were fabricated and cyclically test fired to failure. Six oxygen-free, high-conductivity (OFHC) copper and seven Amzirc chambers were tested. The chamber liners were fabricated of copper or copper alloy and contained milled coolant channels. The chambers were completed by means of an electroformed nickel closeout. The oxidant/fuel ratio for the liquid oxygen and gaseous hydrogen propellants was 6.0. The failures in the OFHC copper chambers were not typical fatigue failures but are described as creep rupture enhanced by ratcheting. The coolant channels bulged toward the chamber centerline, resulting in progressive thinning of the wall during each cycle. The failures in the Amzirc alloy chambers were caused by low-cycle thermal fatigue. The lives were much shorter than were predicted by an analytical structural analysis computer program used in conjunction with fatigue life data from isothermal test specimens, due to the uneven distribution of Zr in the chamber material.

Real-time black carbon emission factor measurements from light duty vehicles.

PubMed

Forestieri, Sara D; Collier, Sonya; Kuwayama, Toshihiro; Zhang, Qi; Kleeman, Michael J; Cappa, Christopher D

2013-11-19

Eight light-duty gasoline low emission vehicles (LEV I) were tested on a Chassis dynamometer using the California Unified Cycle (UC) at the Haagen-Smit vehicle test facility at the California Air Resources Board in El Monte, CA during September 2011. The UC includes a cold start phase followed by a hot stabilized running phase. In addition, a light-duty gasoline LEV vehicle and ultralow emission vehicle (ULEV), and a light-duty diesel passenger vehicle and gasoline direct injection (GDI) vehicle were tested on a constant velocity driving cycle. A variety of instruments with response times ≥0.1 Hz were used to characterize how the emissions of the major particulate matter components varied for the LEVs during a typical driving cycle. This study focuses primarily on emissions of black carbon (BC). These measurements allowed for the determination of BC emission factors throughout the driving cycle, providing insights into the temporal variability of BC emission factors during different phases of a typical driving cycle.

Analysis of the capability to effectively design complementary metal oxide semiconductor integrated circuits

NASA Astrophysics Data System (ADS)

McConkey, M. L.

1984-12-01

A complete CMOS/BULK design cycle has been implemented and fully tested to evaluate its effectiveness and a viable set of computer-aided design tools for the layout, verification, and simulation of CMOS/BULK integrated circuits. This design cycle is good for p-well, n-well, or twin-well structures, although current fabrication technique available limit this to p-well only. BANE, an integrated layout program from Stanford, is at the center of this design cycle and was shown to be simple to use in the layout of CMOS integrated circuits (it can be also used to layout NMOS integrated circuits). A flowchart was developed showing the design cycle from initial layout, through design verification, and to circuit simulation using NETLIST, PRESIM, and RNL from the University of Washington. A CMOS/BULK library was designed and includes logic gates that were designed and completely tested by following this flowchart. Also designed was an arithmetic logic unit as a more complex test of the CMOS/BULK design cycle.

Cycling induced by functional electrical stimulation in children affected by cerebral palsy: case report.

PubMed

Trevisi, E; Gualdi, S; De Conti, C; Salghetti, A; Martinuzzi, A; Pedrocchi, A; Ferrante, S

2012-03-01

Recently, the efficacy of functional electrical stimulation (FES) cycling have been demonstrated on the improvement of strength and motor control in adults with stroke. FES-cycling, providing a repetitive goal-oriented task, could facilitate cortical reorganization and utilization of residual cortico-spinal pathways. These benefits could be more enhanced in children because of the greater plasticity and flexibility of their central nervous system. The aim of the present case report study was to explore the feasibility of FES-cycling in children with cerebral palsy (CP) and to provide a set of instrumental measures able to evaluate the effects of this novel treatment on cycling and walking ability. Interventional study. Two ambulant outpatient children with diplegic CP were recruited by the "E. Medea" Scientific Institute. Patients followed a FES-cycling treatment for 30 minutes a day, 3 days a week for 7 weeks. Pre and post treatment tests were performed, namely clinical measures and electromyographic, kinematic and oxygen expenditure analysis during gait and cycling. The treatment was safe, feasible and well accepted by the 2 children. After treatment both patients achieved a more symmetrical muscular strategy during voluntary cycling and gait and a significant reduction of muscle co-contractions during cycling. These improvements were corroborated by a decrease in oxygen expenditure during the post test for one of the two children, the less impaired, implying a better exploiting of bi-articular muscles. FES-cycling is feasible and safe and it may be an alternative rehabilitation method for diplegic CP patients. The set of instrumental measurements proposed seems to be a valuable tool for functional assessment to identify subclinical anomalies and improvements on cycling and gait in CP patients.

Hydrogeology and Aquifer Storage and Recovery Performance in the Upper Floridan Aquifer, Southern Florida

USGS Publications Warehouse

Reese, Ronald S.; Alvarez-Zarikian, Carlos A.

2007-01-01

Well construction, hydraulic well test, ambient water-quality, and cycle test data were inventoried and compiled for 30 aquifer storage and recovery facilities constructed in the Floridan aquifer system in southern Florida. Most of the facilities are operated by local municipalities or counties in coastal areas, but five sites are currently being evaluated as part of the Comprehensive Everglades Restoration Plan. The relative performance of all sites with adequate cycle test data was determined, and compared with four hydrogeologic and design factors that may affect recovery efficiency. Testing or operational cycles include recharge, storage, and recovery periods that each last days or months. Cycle test data calculations were made including the potable water (chloride concentration of less than 250 milligrams per liter) recovery efficiency per cycle, total recovery efficiency per cycle, and cumulative potable water recovery efficiencies for all of the cycles at each site. The potable water recovery efficiency is the percentage of the total amount of potable water recharged for each cycle that is recovered; potable water recovery efficiency calculations (per cycle and cumulative) were the primary measures used to evaluate site performance in this study. Total recovery efficiency, which is the percent recovery at the end of each cycle, however, can be substantially higher and is the performance measure normally used in the operation of water-treatment plants. The Upper Floridan aquifer of the Floridan aquifer system currently is being used, or planned for use, at 29 of the aquifer storage and recovery sites. The Upper Floridan aquifer is continuous throughout southern Florida, and its overlying confinement is generally good; however, the aquifer contains brackish to saline ground water that can greatly affect freshwater storage and recovery due to dispersive mixing within the aquifer. The hydrogeology of the Upper Floridan varies in southern Florida; confinement between flow zones is better in southwestern Florida than in southeastern Florida. Vertical hydraulic conductivity in the upper part of the aquifer also may be higher in southeastern Florida because of unconformities present at formation contacts within the aquifer that may be better developed in this area. Recovery efficiencies per cycle varied widely. Eight sites had recovery efficiencies of less than about 10 percent for the first cycle, and three of these sites had not yet achieved recoveries exceeding 10 percent, even after three to five cycles. The highest recovery efficiency achieved per cycle was 94 percent. Three southeastern coastal sites and two southwestern coastal sites have achieved potable water recoveries per cycle exceeding 60 percent. One of the southeastern coastal sites and both of the southwestern coastal sites achieved good recoveries, even with long storage periods (from 174 to 191 days). The high recovery efficiencies for some cycles apparently resulted from water banking?an operational approach whereby an initial cycle with a large recharge volume of water is followed by cycles with much smaller recharge volume. This practice flushes out the aquifer around the well and builds up a buffer zone that can maintain high recovery efficiency in the subsequent cycles. The relative performance of all sites with adequate cycle test data was determined. Performance was arbitrarily grouped into ?high? (greater than 40 percent), ?medium? (between 20 and 40 percent), and ?low? (less than 20 percent) categories based primarily on their cumulative recovery efficiency for the first seven cycles, or projected to seven cycles if fewer cycles were conducted. The ratings of three sites, considered to be borderline, were modified using the overall recharge rate derived from the cumulative recharge volumes. A higher overall recharge rate (greater than 300 million gallons per year) can improve recovery efficiency because of the water-bankin

Vapor cycle energy system for implantable circulatory assist devices. Final summary May--Oct 1976

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

Watelet, R.P.; Ruggles, A.E.; Hagen, K.G.

1977-03-01

The report describes the development status of a heart assist system driven by a nuclear-fueled, electronically controlled vapor cycle engine termed the tidal regenerator engine (TRE). The TRE pressurization is controlled by a torque motor coupled to a displacer. The electrical power for the sensor, electronic logic and actuator is provided by thermoelectric modules interposed between the engine superheater and boiler. The TRE is direct-coupled to an assist blood pump which also acts as a blood-cooled heat exchanger, pressure-volume trasformer and sensor for the electronic logic. Engine cycle efficiency in excess of 14% has been demonstrated routinely. Overall system efficiencymore » on 33 watts of over 9% has been demonstrated (implied 13% engine cycle efficiency). A binary version of this engine in the annular configuration is now being tested. The preliminary tests demonstrated 10% cycle efficiency on the first buildup which ran well and started easily.« less

Evaluation of Cycle Life and Characterization of YTP 45 Ah Li-Ion Battery for EMU

NASA Technical Reports Server (NTRS)

Deng, Yi; Jeevarajan, Judith; Rehm, Raymond; Bragg, Bobby; Strangways, Brad

2002-01-01

Li-ion batteries, with longer cycle life and higher energy density features, are now more and more attractive and applied in multiple fields. The YTP 45 Ah Li-ion battery has been evaluated here and may be employed in EMU in the future. Evaluations were on: (1) Cycle life tests - 500 cycles total (completed 40 cycles in simulated shuttle use mode and 460 cycles in an accelerated use mode, and recorded differential voltage of individual cell in battery); (2) Characterization test - discharge capacity measurement in environment temperature of -10, 25, 50 C before and after 500 cycles; and (3) Thermal testing - charge and discharge at 50 C and -10 C before and after 500 cycles. The battery showed less than a 9% drop of initial discharge capacity and energy within 500 cycles with 475 cycles 59% DOD plus 25 cycles 100% DOD. The EOD voltage ranged from 16.0 to 18.0 V, which fits the requirement for operating the EMU.

Testing and development of electric vehicle batteries for EPRI Electric Transportation Program

NASA Astrophysics Data System (ADS)

1985-11-01

Argonne National Laboratory conducted an electric-vehicle battery testing and development program for the Electric Power Research Institute. As part of this program, eighteen battery modules previously developed by Johnson Controls, Inc. were tested. This type of battery (EV-2300 - an improved state-of-the-art lead-acid battery) was designed specifically for improved performance, range, and life in electric vehicles. In order to obtain necessary performance data, the batteries were tested under various duty cycles typical of normal service. This program, supported by the Electric Power Research Institute, consisted of three tasks: determination of the effect of cycle life vs peak power and rest period, determination of the impact of charge method on cycle life, and evaluation of the EV-2300 battery system. Two supporting studies were also carried out: one on thermal management of electric-vehicle batteries and one on enhanced utilization of active material in lead-acid batteries.

Cardiopulmonary resuscitation duty cycle in out-of-hospital cardiac arrest.

PubMed

Johnson, Bryce V; Johnson, Bryce; Coult, Jason; Fahrenbruch, Carol; Blackwood, Jennifer; Sherman, Larry; Kudenchuk, Peter; Sayre, Michael; Rea, Thomas

2015-02-01

Duty cycle is the portion of time spent in compression relative to total time of the compression-decompression cycle. Guidelines recommend a 50% duty cycle based largely on animal investigation. We undertook a descriptive evaluation of duty cycle in human resuscitation, and whether duty cycle correlates with other CPR measures. We calculated the duty cycle, compression depth, and compression rate during EMS resuscitation of 164 patients with out-of-hospital ventricular fibrillation cardiac arrest. We captured force recordings from a chest accelerometer to measure ten-second CPR epochs that preceded rhythm analysis. Duty cycle was calculated using two methods. Effective compression time (ECT) is the time from beginning to end of compression divided by total period for that compression-decompression cycle. Area duty cycle (ADC) is the ratio of area under the force curve divided by total area of one compression-decompression cycle. We evaluated the compression depth and compression rate according to duty cycle quartiles. There were 369 ten-second epochs among 164 patients. The median duty cycle was 38.8% (SD=5.5%) using ECT and 32.2% (SD=4.3%) using ADC. A relatively shorter compression phase (lower duty cycle) was associated with greater compression depth (test for trend <0.05 for ECT and ADC) and slower compression rate (test for trend <0.05 for ADC). Sixty-one of 164 patients (37%) survived to hospital discharge. Duty cycle was below the 50% recommended guideline, and was associated with compression depth and rate. These findings provider rationale to incorporate duty cycle into research aimed at understanding optimal CPR metrics. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Metallic positive expulsion diaphragms

NASA Technical Reports Server (NTRS)

Gleich, D.

1972-01-01

High-cycle life ring-reinforced hemispherical type positive expulsion diaphragm performance was demonstrated by room temperature fluid expulsion tests of 13" diameter, 8 mil thick stainless steel configurations. A maximum of eleven (11) leak-free, fluid expulsions were achieved by a 25 deg cone angle diaphragm hoop-reinforced with .110-inch cross-sectional diameter wires. This represents a 70% improvement in diaphragm reversal cycle life compared to results previously obtained. The reversal tests confirmed analytic predictions for diaphragm cycle life increases due to increasing values of diaphragm cone angle, radius to thickness ratio and material strain to necking capacity. Practical fabrication techniques were demonstrated for forming close-tolerance, thin corrugated shells and for obtaining closely controlled reinforcing ring stiffness required to maximize diaphragm cycle life. A non-destructive inspection technique for monitoring large local shell bending strains was developed.

Design and testing of an MRI-compatible cycle ergometer for non-invasive cardiac assessments during exercise

PubMed Central

2012-01-01

Background Magnetic resonance imaging (MRI) is an important tool for cardiac research, and it is frequently used for resting cardiac assessments. However, research into non-pharmacological stress cardiac evaluation is limited. Methods We aimed to design a portable and relatively inexpensive MRI cycle ergometer capable of continuously measuring pedalling workload while patients exercise to maintain target heart rates. Results We constructed and tested an MRI-compatible cycle ergometer for a 1.5 T MRI scanner. Resting and sub-maximal exercise images (at 110 beats per minute) were successfully obtained in 8 healthy adults. Conclusions The MRI-compatible cycle ergometer constructed by our research group enabled cardiac assessments at fixed heart rates, while continuously recording power output by directly measuring pedal force and crank rotation. PMID:22423637

NASA Lewis advanced IPV nickel-hydrogen technology

NASA Technical Reports Server (NTRS)

Smithrick, John J.; Britton, Doris L.

1993-01-01

Individual pressure vessel (IPV) nickel-hydrogen technology was advanced at NASA Lewis and under Lewis contracts. Some of the advancements are as follows: to use 26 percent potassium hydroxide electrolyte to improve cycle life and performance, to modify the state of the art cell design to eliminate identified failure modes and further improve cycle life, and to develop a lightweight nickel electrode to reduce battery mass, hence reduce launch and/or increase satellite payload. A breakthrough in the LEO cycle life of individual pressure vessel nickel-hydrogen battery cells was reported. The cycle life of boiler plate cells containing 26 percent KOH electrolyte was about 40,000 accelerated LEO cycles at 80 percent DOD compared to 3,500 cycles for cells containing 31 percent KOH. Results of the boiler plate cell tests have been validated at NWSC, Crane, Indiana. Forty-eight ampere-hour flight cells containing 26 and 31 percent KOH have undergone real time LEO cycle life testing at an 80 percent DOD, 10 C. The three cells containing 26 percent KOH failed on the average at cycle 19,500. The three cells containing 31 percent KOH failed on the average at cycle 6,400. Validation testing of NASA Lewis 125 Ah advanced design IPV nickel-hydrogen flight cells is also being conducted at NWSC, Crane, Indiana under a NASA Lewis contract. This consists of characterization, storage, and cycle life testing. There was no capacity degradation after 52 days of storage with the cells in the discharged state, on open circuit, 0 C, and a hydrogen pressure of 14.5 psia. The catalyzed wall wick cells have been cycled for over 22,694 cycles with no cell failures in the continuing test. All three of the non-catalyzed wall wick cells failed (cycles 9,588; 13,900; and 20,575). Cycle life test results of the Fibrex nickel electrode has demonstrated the feasibility of an improved nickel electrode giving a higher specific energy nickel-hydrogen cell. A nickel-hydrogen boiler plate cell using an 80 mil thick, 90 percent porous Fibrex nickel electrode has been cycled for 10,000 cycles at 40 percent DOD.

Analysis of critical thinking ability of VII grade students based on the mathematical anxiety level through learning cycle 7E model

NASA Astrophysics Data System (ADS)

Widyaningsih, E.; Waluya, S. B.; Kurniasih, A. W.

2018-03-01

This study aims to know mastery learning of students’ critical thinking ability with learning cycle 7E, determine whether the critical thinking ability of the students with learning cycle 7E is better than students’ critical thinking ability with expository model, and describe the students’ critical thinking phases based on the mathematical anxiety level. The method is mixed method with concurrent embedded. The population is VII grade students of SMP Negeri 3 Kebumen academic year 2016/2017. Subjects are determined by purposive sampling, selected two students from each level of mathematical anxiety. Data collection techniques include test, questionnaire, interview, and documentation. Quantitative data analysis techniques include mean test, proportion test, difference test of two means, difference test of two proportions and for qualitative data used Miles and Huberman model. The results show that: (1) students’ critical thinking ability with learning cycle 7E achieve mastery learning; (2) students’ critical thinking ability with learning cycle 7E is better than students’ critical thinking ability with expository model; (3) description of students’ critical thinking phases based on the mathematical anxiety level that is the lower the mathematical anxiety level, the subjects have been able to fulfil all of the indicators of clarification, assessment, inference, and strategies phases.

Toward a mechanistic understanding of the damage evolution of SnAgCu solder joints in accelerated thermal cycling test

NASA Astrophysics Data System (ADS)

Mahin Shirazi, Sam

Accelerated thermal cycling (ATC) tests are the most commonly used tests for the thermo-mechanical performance assessment of microelectronics assemblies. Currently used reliability models have failed to incorporate the microstructural dependency of lead free solder joint behavior and its microstructure evolution during cycling. Thus, it is essential to have a mechanistic understanding of the effect of cycling parameters on damage evolution and failure of lead free solder joints in ATC. Recrystallization has been identified as the damage rate controlling mechanism in ATC. Usually it takes 1/3 of life for completion of recrystallization regardless of cycling parameters. Thus, the life of the solder joints can be predicted by estimating global recrystallization. The objective of the first part of the study was to examine whether the damage scenario applies in service is the same as the harsh thermal cycling tests (i.e. 0/100 °C and -40/125 °C) commonly used in industry. Microstructure analysis results on a variety of lead free solder SnAgCu assemblies subjected to the both harsh (0/100 °C) and mild (20/80 °C) ATC confirmed similar failure mechanism under the both testing conditions. Sn grain morphology (interlaced versus beach ball) has a significant effect on the thermo-mechanical performance (and thus the model) of the lead free solder joints. The longer thermal cycling lifetime observed in the interlaced solder joints subjected to the ATC compared to the beach ball structure was correlated to the different initial microstructure and the microstructure evolution during cycling. For the modeling proposes, the present study was focused on Sn-Ag-Cu solder joints with either a single Sn grain or beach ball structure. Microstructural analysis results of the simulated thermal cycling experiment revealed that, the life can be approximated as determined by the accumulation of a certain amount of work during the high temperature dwells. Finally the effect of precipitates spacing on acceleration factor was investigated. Results indicated that a smaller initial precipitate spacing would tend to result in a longer life in mild thermal cycling/service (where there is lower stresses). Accordingly, it is essential to incorporate the dependence of damage rate (i.e. recrystallization) on precipitate coarsening in any predictions.

40 CFR 600.207-12 - Calculation and use of vehicle-specific 5-cycle-based fuel economy and CO2 emission values for...

Code of Federal Regulations, 2012 CFR

2012-07-01

... economy and CO2 emission values from the tests performed using gasoline or diesel test fuel. (ii) Calculate the 5-cycle city and highway fuel economy and CO2 emission values from the tests performed using alcohol or natural gas test fuel, if 5-cycle testing has been performed. Otherwise, the procedure in § 600...

40 CFR 600.207-12 - Calculation and use of vehicle-specific 5-cycle-based fuel economy and CO2 emission values for...

Code of Federal Regulations, 2014 CFR

2014-07-01

... economy and CO2 emission values from the tests performed using gasoline or diesel test fuel. (ii) Calculate the 5-cycle city and highway fuel economy and CO2 emission values from the tests performed using alcohol or natural gas test fuel, if 5-cycle testing has been performed. Otherwise, the procedure in § 600...

40 CFR 600.207-12 - Calculation and use of vehicle-specific 5-cycle-based fuel economy and CO2 emission values for...

Code of Federal Regulations, 2013 CFR

2013-07-01

... economy and CO2 emission values from the tests performed using gasoline or diesel test fuel. (ii) Calculate the 5-cycle city and highway fuel economy and CO2 emission values from the tests performed using alcohol or natural gas test fuel, if 5-cycle testing has been performed. Otherwise, the procedure in § 600...

Multiple autoclave cycles affect the surface of rotary nickel-titanium files: an atomic force microscopy study.

PubMed

Valois, Caroline R A; Silva, Luciano P; Azevedo, Ricardo B

2008-07-01

The purpose of this study was to evaluate the surface of rotary nickel-titanium (Ni-Ti) files after multiple autoclave cycles. Two different types of rotary Ni-Ti (Greater Taper and ProFile) were attached to a glass base. After 1, 5, and 10 autoclave cycles the files were positioned in the atomic force microscope. The analyses were performed on 15 different points. The same files were used as control before any autoclave cycle. The following vertical topographic parameters were measured: arithmetic mean roughness, maximum height, and root mean square. The differences were tested by analysis of variance with Tukey test. All topographic parameters were higher for both Greater Taper and ProFile after 10 cycles compared with the control (P < .05). ProFile also showed higher topographic parameters after 5 cycles compared with the control (P < .05). The results indicated that multiple autoclave cycles increase the depth of surface irregularities located on rotary Ni-Ti files.

Can more than one incremental cycling test be performed within one day?

PubMed

Scharhag-Rosenberger, Friederike; Carlsohn, Anja; Lundby, Carsten; Schüler, Stefan; Mayer, Frank; Scharhag, Jürgen

2014-01-01

Changes in performance parameters over four consecutive maximal incremental cycling tests were investigated to determine how many tests can be performed within one single day without negatively affecting performance. Sixteen male and female subjects (eight trained (T): 25 ± 3 yr, BMI 22.6 ± 2.5 kg·m(-2), maximal power output (P(max)) 4.6 ± 0.5 W·kg(-1); eight untrained (UT): 27 ± 3 yr, BMI 22.3 ± 1.2 kg·m(-2), P(max) 2.9 ± 0.3 W·kg(-1)) performed four successive maximal incremental cycling tests separated by 1.5 h of passive rest. Individual energy requirements were covered by standardised meals between trials. Maximal oxygen uptake (VO(2max)) remained unchanged over the four tests in both groups (P = 0.20 and P = 0.33, respectively). P(max) did not change in the T group (P = 0.32), but decreased from the third test in the UT group (P < 0.01). Heart rate responses to submaximal exercise were elevated from the third test in the T group and from the second test in the UT group (P < 0.05). The increase in blood lactate shifted rightward over the four tests in both groups (P < 0.001 and P < 0.01, respectively). Exercise-induced net increases in epinephrine and norepinephrine were not different between the tests in either group (P ≥ 0.15). If VO(2max) is the main parameter of interest, trained and untrained individuals can perform at least four maximal incremental cycling tests per day. However, because other parameters changed after the first and second test, respectively, no more than one test per day should be performed if parameters other than VO(2max) are the prime focus.

The development and reliability of a repeated anaerobic cycling test in female ice hockey players.

PubMed

Wilson, Kier; Snydmiller, Gary; Game, Alex; Quinney, Art; Bell, Gordon

2010-02-01

The purpose of this study was to develop and assess the reliability of a repeated anaerobic power cycling test designed to mimic the repeated sprinting nature of the sport of ice hockey. Nineteen female varsity ice hockey players (mean X +/- SD age, height and body mass = 21 +/- 2 yr, 166.6 +/- 6.3 cm and 62.3 +/- 7.3) completed 3 trials of a repeated anaerobic power test on a Monark cycle ergometer on different days. The test consisted of "all-out" cycling for 5 seconds separated by 10 seconds of low-intensity cycling, repeated 4 times. The relative load factor used for the resistance setting was equal to 0.095 kg per kilogram body mass. There was no significant difference between the peak 5-second power output (PO), mean PO, or the fatigue index (%) among the 3 different trials. The peak 5-second PO was 702.6 +/- 114.8 w and 11.3 +/- 1.1 w x kg, whereas the mean PO across the 4 repeats was 647.1 +/- 96.3 w and 10.4 +/- 1.0 w x kg averaged for the 3 different tests. The fatigue index averaged 17.8 +/- 6.5%. The intraclass correlation coefficient for peak 5-second, mean PO, and fatigue index was 0.82, 0.86, and 0.82, respectively. This study reports the methodology of a repeated anaerobic power cycling test that was reliable for the measurement of PO and calculated fatigue index in varsity women ice hockey players and can be used as a laboratory-based assessment of repeated anaerobic fitness.

Development of a multi-cycle shear-compression testing for the modeling of severe plastic deformation

NASA Astrophysics Data System (ADS)

Pesin, A.; Pustovoytov, D.; Lokotunina, N.

2017-12-01

The mechanism of severe plastic deformation comes from very significant shear strain. Shear-compression testing of materials is complicated by the fact that a state of large equivalent strain with dominant shear strain is not easily achievable. This paper presents the novel technique of laboratory simulation of severe plastic deformation by multi-cycle shear-compression testing at room temperature with equivalent strain e=1…5. The specimen consisted of a parallelepiped having an inclined gauge section created by two diametrically opposed semi-circular slots which were machined at 45°. Height of the specimen was 50 mm, section dimensions were 25×25 mm, gauge thickness was 5.0 mm and gauge width was 6.0 mm. The specimen provided dominant shear strain in an inclined gauge-section. The level of shear strain and equivalent strain was controlled through adjustment of the height reduction of the specimen, load application direction and number of cycles of shear-compression. Aluminium alloy Al-6.2Mg-0.7Mn was used as a material for specimen. FE simulation and analysis of the stress-strain state were performed. The microstructure of the specimen after multi-cycle shear-compression testing with equivalent strain e=1…5 was examined by optical and scanning electron microscope.

Space Station Freedom NiH2 cell testing program

NASA Technical Reports Server (NTRS)

Moore, Bruce; Frate, Dave

1994-01-01

Testing for the Space Station Freedom Nickel Hydrogen Cell Test Program began in 1990 at Crave Division, Naval Surface Warfare Center. The program has included receipt inspection, random vibration, acceptance, characterization, and life cycle testing of Ni-H2 cells in accordance with the NASA LeRC Interagency Order C-31001-J. A total of 400 Ni-H2 cells have been received at NAVSURFWARCENDIV Crane from three separate manufacturers; Yardney Technical Products (Yardney), Eagle Picher Industries (Eagle Picher), and Gates Energy Products (Gates). Of those, 308 cells distributed among 39 packs have undergone life cycle testing under a test regime simulating low earth orbit conditions. As of 30 September 1993, there are 252 cells assembled into 32 packs still on life cycle test. Since the beginning of the program, failed cells have been detected in all phases of testing. The failures include the following; seven 65 AmpHr and 81 AmpHr Yardney cells were found to be leaking KOH on receipt, one 65 AmpHr Eagle Picher cell failed the acceptance test, one 65 AmpHr Gates cell failed during the characterization test, and six 65 AmpHr Gates cells failed the random vibration test. Of the 39 life cycle packs, testing on seven packs, 56 cells, has been suspended because of low end of discharge voltages. All of the failed life cycle packs were cycled at 60% depth of discharge.

Emission performance of ceramic preconverters evaluated by FTP and Euro Stage III emission test cycle

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

Locker, R.J.; Then, P.M.; Zink, U.

1996-09-01

Preconverters and close-coupled main converters are viewed as key components in advanced emission systems to help the auto industry comply with tightened emission regulations in North America and Europe. Due to their close position to the exhaust manifold when compared to current main catalysts, the mechanical and thermal durability requirements on such close-coupled converters are significantly increased. A set of representative preconverter systems, with respect to back pressure and surface area, ceramic and metal substrate material was exposed to a 100 hour engine aging cycle, which is equivalent to approximately 80,000 kilometers under European driving conditions. This aging cycle ismore » used by the German Autoconsortium (ZDAKW). In order to address the high thermal load in a close-coupled position, the preconverter inlet gas temperature has been elevated to a maximum of 950 C at stoichiometry. Maximum preconverter midbed temperature has been found close to 1,000 C. State-of-the-art catalytic coatings were used on the preconverters (Pd-only) and main converters (Trimetal). Emission tests using the new European test cycle (EDC 99), as well as the FTP 75 test cycle have been used to evaluate the catalytic performance. These tests were done during the aging at 20, 60 and 100 hours on the preconverters alone and on the combination of pre- and main converters. The impact of air injection has been studied on the complete preconverter/mainconverter system. The Celcor XT{trademark} ceramic preconverter proved mechanically and catalytically intact during the severe 100 hour aging cycle. The metallic and ceramic preconverter systems demonstrated equivalent catalytic performance.« less

Thermal-Fatigue Crack-Growth Characteristics and Mechanical Strain Cycling Behavior of A-286 Discaloy, and 16-25-6 Austenitic Steels

NASA Technical Reports Server (NTRS)

Smith, Robert W.; Smith, Gordon T.

1960-01-01

Thermal-fatigue crack-growth characteristics of notched- and unnotched-disk specimens of A-286, Discaloy, hot-cold worked 16-25-6, and overaged 16-25-6 were experimentally studied. Separately controlled variables were total strain range (0.0043 to 0.0079 in./in.), maximum cycle temperature (1300 and 1100 F), and hold time at maximum temperature (O and 5 min). A limited number of mechanical, push-pull, constant-strain cycle tests at room temperature were made using notched and un-notched bars of the same materials. In these tests the number of cycles to failure as well as the variation of load change with accumulated cycles was measured, and the effects of mean stress were observed. Constant-strain-range mechanical-fatigue tests at room temperature revealed notched-bar fatigue life to be strongly influenced by mean stress. For a specific strain range, the longest fatigue life was always found to be associated with the least-tensile (or most compressive) mean stress. By defining thermal-fatigue life as the number of cycles required to produce a crack area of 6000 square mils, the relative thermal-fatigue resistances of the test materials were established. Notched-disk specimens of A-286 and Discaloy steels exhibited longer fatigue lives than either hot-cold worked or overaged 16-25-6. On the other hand, unnotched-disk specimens of Discaloy and hot-cold worked 16-25-6 had longer lives than A-286 and overaged 16-25-6. Separation of the crack-growth data into microstage and macrostage periods revealed that the macrostage period accounted for the greatest part of the difference among materials when tested in the notched configuration, while the microstage was largely responsible for the differences encountered in unnotched disks.

40 CFR 600.207-08 - Calculation and use of vehicle-specific 5-cycle-based fuel economy values for vehicle...

Code of Federal Regulations, 2012 CFR

2012-07-01

... economy values from the tests performed using gasoline or diesel test fuel. (ii)(A) Calculate the 5-cycle city and highway fuel economy values from the tests performed using alcohol or natural gas test fuel...-specific 5-cycle-based fuel economy values for vehicle configurations. 600.207-08 Section 600.207-08...

40 CFR 600.207-08 - Calculation and use of vehicle-specific 5-cycle-based fuel economy values for vehicle...

Code of Federal Regulations, 2013 CFR

2013-07-01

... economy values from the tests performed using gasoline or diesel test fuel. (ii)(A) Calculate the 5-cycle city and highway fuel economy values from the tests performed using alcohol or natural gas test fuel...-specific 5-cycle-based fuel economy values for vehicle configurations. 600.207-08 Section 600.207-08...

Brachial artery endothelial function is stable across a menstrual and oral contraceptive pill cycle, but lower in premenopausal women than age-matched men.

PubMed

Shenouda, Ninette; Priest, Stacey E; Rizzuto, Vanessa I; MacDonald, Maureen J

2018-05-04

Sex hormone concentrations differ between men, premenopausal women with natural menstrual cycles (NAT), and premenopausal women using oral contraceptive pills (OCP), as well as across menstrual or OCP phases. This study sought to investigate how differences in sex hormones, particularly estradiol, between men and women and across cycle phases, may influence brachial artery endothelial function. Fifty-three healthy adults (22{plus minus}3 yrs; 20 men, 15 NAT, 18 second, third or fourth generation OCP) underwent assessments of sex hormones and endothelial (flow-mediated dilation test, FMD) and smooth muscle (nitroglycerin test, NTG) function. Men were tested three times at one-week intervals, and women were tested three times throughout a single menstrual or OCP cycle (NAT: menstrual, mid-follicular, luteal; OCP: placebo/no pill, 'early' and 'late' active pill). Endogenous estradiol concentration was comparable between men and women in their NAT menstrual or OCP placebo phase (p=0.36) but increased throughout a NAT cycle (p<0.001). Allometrically scaled FMD did not change across a NAT or OCP cycle but was lower in both groups of women than men (p=0.005), whereas scaled NTG was lower only in NAT women (p=0.001). Changes in estradiol across a NAT cycle were not associated with changes in relative FMD (r2=0.01, p=0.62) or NTG (r2=0.09, p=0.13). Duration of OCP use was negatively associated with the average relative FMD for second generation OCP users only (r=-0.65, p=0.04). Our findings suggest that brachial endothelial function is unaffected by cyclic hormonal changes in premenopausal women but may be negatively impacted by longer term use of second generation OCPs.

Validity and reliability of the PowerTap mobile cycling powermeter when compared with the SRM Device.

PubMed

Bertucci, W; Duc, S; Villerius, V; Pernin, J N; Grappe, F

2005-12-01

The SRM power measuring crank system is nowadays a popular device for cycling power output (PO) measurements in the field and in laboratories. The PowerTap (CycleOps, Madison, USA) is a more recent and less well-known device that allows mobile PO measurements of cycling via the rear wheel hub. The aim of this study is to test the validity and reliability of the PowerTap by comparing it with the most accurate (i.e. the scientific model) of the SRM system. The validity of the PowerTap is tested during i) sub-maximal incremental intensities (ranging from 100 to 420 W) on a treadmill with different pedalling cadences (45 to 120 rpm) and cycling positions (standing and seated) on different grades, ii) a continuous sub-maximal intensity lasting 30 min, iii) a maximal intensity (8-s sprint), and iiii) real road cycling. The reliability is assessed by repeating ten times the sub-maximal incremental and continuous tests. The results show a good validity of the PowerTap during sub-maximal intensities between 100 and 450 W (mean PO difference -1.2 +/- 1.3 %) when it is compared to the scientific SRM model, but less validity for the maximal PO during sprint exercise, where the validity appears to depend on the gear ratio. The reliability of the PowerTap during the sub-maximal intensities is similar to the scientific SRM model (the coefficient of variation is respectively 0.9 to 2.9 % and 0.7 to 2.1 % for PowerTap and SRM). The PowerTap must be considered as a suitable device for PO measurements during sub-maximal real road cycling and in sub-maximal laboratory tests.

40 CFR 1033.520 - Alternative ramped modal cycles.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) Following the completion of the third test phase of the applicable ramped modal cycle, conduct the post... POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Test Procedures § 1033.520 Alternative ramped modal... locomotive notch settings. Ramped modal cycles combine multiple test modes of a discrete-mode steady-state...

40 CFR 86.1341-90 - Test cycle validation criteria.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Test cycle validation criteria. 86... Procedures § 86.1341-90 Test cycle validation criteria. (a) To minimize the biasing effect of the time lag... brake horsepower-hour. (c) Regression line analysis to calculate validation statistics. (1) Linear...

40 CFR 86.1341-90 - Test cycle validation criteria.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 20 2013-07-01 2013-07-01 false Test cycle validation criteria. 86... Procedures § 86.1341-90 Test cycle validation criteria. (a) To minimize the biasing effect of the time lag... brake horsepower-hour. (c) Regression line analysis to calculate validation statistics. (1) Linear...

40 CFR 86.1341-90 - Test cycle validation criteria.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 20 2012-07-01 2012-07-01 false Test cycle validation criteria. 86... Procedures § 86.1341-90 Test cycle validation criteria. (a) To minimize the biasing effect of the time lag... brake horsepower-hour. (c) Regression line analysis to calculate validation statistics. (1) Linear...

40 CFR 86.1537 - Idle test run.

Code of Federal Regulations, 2013 CFR

2013-07-01

... EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Emission Regulations for Otto-Cycle...-Cycle Heavy-Duty Engines, New Otto-Cycle Light-Duty Trucks, and New Methanol-Fueled Natural Gas-Fueled, and Liquefied Petroleum Gas-Fueled Diesel-Cycle Light-Duty Trucks; Idle Test Procedures § 86.1537 Idle...

40 CFR 86.1537 - Idle test run.

Code of Federal Regulations, 2012 CFR

2012-07-01

... EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Emission Regulations for Otto-Cycle...-Cycle Heavy-Duty Engines, New Otto-Cycle Light-Duty Trucks, and New Methanol-Fueled Natural Gas-Fueled, and Liquefied Petroleum Gas-Fueled Diesel-Cycle Light-Duty Trucks; Idle Test Procedures § 86.1537 Idle...

40 CFR 94.105 - Duty cycles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Duty cycles. 94.105 Section 94.105... EMISSIONS FROM MARINE COMPRESSION-IGNITION ENGINES Test Procedures § 94.105 Duty cycles. (a) Overview. For....8(e), engines shall be tested using the appropriate duty cycles described in this section. (b...

40 CFR 86.1537 - Idle test run.

Code of Federal Regulations, 2010 CFR

2010-07-01

... EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Emission Regulations for Otto-Cycle...-Cycle Heavy-Duty Engines, New Otto-Cycle Light-Duty Trucks, and New Methanol-Fueled Natural Gas-Fueled, and Liquefied Petroleum Gas-Fueled Diesel-Cycle Light-Duty Trucks; Idle Test Procedures § 86.1537 Idle...

40 CFR 86.1527 - Idle test procedure; overview.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Regulations for Otto-Cycle Heavy-Duty Engines, New Methanol-Fueled Natural Gas-Fueled, and Liquefied Petroleum Gas-Fueled Diesel-Cycle Heavy-Duty Engines, New Otto-Cycle Light-Duty Trucks, and New Methanol-Fueled Natural Gas-Fueled, and Liquefied Petroleum Gas-Fueled Diesel-Cycle Light-Duty Trucks; Idle Test...

United States Advanced Ultra-Supercritical Component Test Facility for 760°C Steam Power Plants ComTest Project

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

Hack, Horst; Purgert, Robert Michael

Following the successful completion of a 15-year effort to develop and test materials that would allow coal-fired power plants to be operated at advanced ultra-supercritical (A-USC) steam conditions, a United States-based consortium is presently engaged in a project to build an A-USC component test facility (ComTest). A-USC steam cycles have the potential to improve cycle efficiency, reduce fuel costs, and reduce greenhouse gas emissions. Current development and demonstration efforts are focused on enabling the construction of A-USC plants, operating with steam temperatures as high as 1400°F (760°C) and steam pressures up to 5000 psi (35 MPa), which can potentially increasemore » cycle efficiencies to 47% HHV (higher heating value), or approximately 50% LHV (lower heating value), and reduce CO 2 emissions by roughly 25%, compared to today’s U.S. fleet. A-USC technology provides a lower-cost method to reduce CO 2 emissions, compared to CO 2 capture technologies, while retaining a viable coal option for owners of coal generation assets. Among the goals of the ComTest facility are to validate that components made from advanced nickel-based alloys can operate and perform under A-USC conditions, to accelerate the development of a U.S.-based supply chain for the full complement of A-USC components, and to decrease the uncertainty of cost estimates for future A-USC power plants. The configuration of the ComTest facility would include the key A-USC technology components that were identified for expanded operational testing, including a gas-fired superheater, high-temperature steam piping, steam turbine valve, and cycling header component. Membrane walls in the superheater have been designed to operate at the full temperatures expected in a commercial A-USC boiler, but at a lower (intermediate) operating pressure. This superheater has been designed to increase the temperature of the steam supplied by the host utility boiler up to 1400°F (760°C). The steam turbine stop and control valve component has been designed to operate at full A-USC temperatures, and would be tested both in throttling operation and to accumulate accelerated, repetitive stroke cycles. A cycling header component has been designed to confirm the suitability of new high-temperature nickel alloys to cycling operation, expected of future coal-fired power plants. Current test plans would subject these components to A-USC operating conditions for at least 8,000 hours by September 2020. The ComTest project is managed by Energy Industries of Ohio, and technically directed by the Electric Power Research Institute, Inc., with General Electric designing the A-USC components. This consortium is completing the Detailed Engineering phase of the project, with procurement scheduled to begin in late 2017. The effort is primarily funded by the U.S. Department of Energy, through the National Energy Technology Laboratory, along with the Ohio Development Services Agency. This presentation outlines the motivation for the project, explains the project’s structure and schedule, and provides technical details on the design of the ComTest facility.« less

Real-world vehicle emission factors in Chinese metropolis city--Beijing.

PubMed

Wang, Qi-dong; He, Ke-bin; Huo, Hong; Lents, James

2005-01-01

The dynamometer tests with different driving cycles and the real-world tests are presented. Results indicated the pollutants emission factors and fuel consumption factor with ECE15 + EUDC driving cycle usually take the lowest value and with real world driving cycle occur the highest value, and different driving cycles will lead to significantly different vehicle emission factors with the same vehicle. Relative to the ECE15 + EUDC driving cycle, the increasing rate of pollutant emission factors of CO, NOx and HC are - 0.42-2.99, -0.32-0.81 and -0.11-11 with FTP75 testing, 0.11-1.29, -0.77-0.64 and 0.47-10.50 with Beijing 1997 testing and 0.25-1.83, 0.09-0.75 and - 0.58-1.50 with real world testing. Compared to the carburetor vehicles, the retrofit and MPI + TWC vehicles' pollution emissionfactors decrease with different degree. The retrofit vehicle (Santana) will reduce 4.44%-58.44% CO, -4.95%-36.79% NOx, -32.32%-33.89% HC, and -9.39%-14.29% fuel consumption, and especially that the MPI + TWC vehicle will decrease CO by 82.48%-91.76%, NOx by 44.87%-92.79%, HC by 90.00%-93.89% and fuel consumption by 5.44%-10.55%. Vehicles can cause pollution at a very high rate when operated in high power modes; however, they may not often operate in these high power modes. In analyzing vehicle emissions, it describes the fraction of time that vehicles operate in various power modes. In Beijing, vehicles spend 90% of their operation in low power modes or decelerating.

Thermal Cycling and High Temperature Reverse Bias Testing of Control and Irradiated Gallium Nitride Power Transistors

NASA Technical Reports Server (NTRS)

Patterson, Richard L.; Boomer, Kristen T.; Scheick, Leif; Lauenstein, Jean-Marie; Casey, Megan; Hammoud, Ahmad

2014-01-01

The power systems for use in NASA space missions must work reliably under harsh conditions including radiation, thermal cycling, and exposure to extreme temperatures. Gallium nitride semiconductors show great promise, but information pertaining to their performance is scarce. Gallium nitride N-channel enhancement-mode field effect transistors made by EPC Corporation in a 2nd generation of manufacturing were exposed to radiation followed by long-term thermal cycling and testing under high temperature reverse bias conditions in order to address their reliability for use in space missions. Result of the experimental work are presented and discussed.

Influence of the number of cycles on shear fatigue strength of resin composite bonded to enamel and dentin using dental adhesives in self-etching mode.

PubMed

Tsujimoto, Akimasa; Barkmeier, Wayne W; Erickson, Robert L; Takamizawa, Toshiki; Latta, Mark A; Miyazaki, Masashi

2018-01-30

The influence of the number of cycles on shear fatigue strength to enamel and dentin using dental adhesives in self-etch mode was investigated. A two-step self-etch adhesive and two universal adhesives were used to bond to enamel and dentin in self-etch mode. Initial shear bond strength and shear fatigue strength to enamel and dentin using the adhesive in self-etch mode were determined. Fatigue testing was used with 20 Hz frequency and cycling periods of 50,000, 100,000 and 1,000,000 cycles, or until failure occurred. For each of the cycling periods, there was no significant difference in shear fatigue strength across the cycling periods for the individual adhesives. Differences in shear fatigue strength were found between the adhesives within the cycling periods. Regardless of the adhesive used in self-etch mode for bonding to enamel or dentin, shear fatigue strength was not influenced by the number of cycles used for shear fatigue strength testing.

Micromechanical properties of canine femoral articular cartilage following multiple freeze-thaw cycles.

PubMed

Peters, Abby E; Comerford, Eithne J; Macaulay, Sophie; Bates, Karl T; Akhtar, Riaz

2017-07-01

Tissue material properties are crucial to understanding their mechanical function, both in healthy and diseased states. However, in certain circumstances logistical limitations can prevent testing on fresh samples necessitating one or more freeze-thaw cycles. To date, the nature and extent to which the material properties of articular cartilage are altered by repetitive freezing have not been explored. Therefore, the aim of this study is to quantify how articular cartilage mechanical properties, measured by nanoindentation, are affected by multiple freeze-thaw cycles. Canine cartilage plugs (n = 11) from medial and lateral femoral condyles were submerged in phosphate buffered saline, stored at 3-5°C and tested using nanoindentation within 12h. Samples were then frozen at -20°C and later thawed at 3-5°C for 3h before material properties were re-tested and samples re-frozen under the same conditions. This process was repeated for all 11 samples over three freeze-thaw cycles. Overall mean and standard deviation of shear storage modulus decreased from 1.76 ± 0.78 to 1.21 ± 0.77MPa (p = 0.91), shear loss modulus from 0.42 ± 0.19 to 0.39 ± 0.17MPa (p=0.70) and elastic modulus from 5.13 ± 2.28 to 3.52 ± 2.24MPa (p = 0.20) between fresh and three freeze-thaw cycles respectively. The loss factor increased from 0.31 ± 0.38 to 0.71 ± 1.40 (p = 0.18) between fresh and three freeze-thaw cycles. Inter-sample variability spanned as much as 10.47MPa across freezing cycles and this high-level of biological variability across samples likely explains why overall mean "whole-joint" trends do not reach statistical significance across the storage conditions tested. As a result multiple freeze-thaw cycles cannot be explicitly or statistically linked to mechanical changes within the cartilage. However, the changes in material properties observed herein may be sufficient in magnitude to impact on a variety of clinical and scientific studies of cartilage, and should be considered when planning experimental protocols. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Reliability of Tin Silver Copper and mixed solders under variable loading conditions

NASA Astrophysics Data System (ADS)

Jaradat, Younis

Industry use of lead free solder joints necessitates accurate modeling in predicting life in service. Yet, current extrapolations of accelerated test results do not actuate realistic conditions. This research focuses on joint properties of Pb-mixed and Pb-free solder alloys in order to explain material behavior subject to certain test conditions, i.e., varying cycling amplitudes. Additionally, this research will begin with extensive studies on backward compatible solder joints from the material's behavior to its reliability under displacement and load controlled fatigue tests. We address the evolution of the joint's microstructure ergo its properties and performance (mixed solder joints). The present work reports results of reflowing 30 mil SAC305 balls onto Cu, and ENIG coated BGA pads with different amounts of SnPb paste, aging and/or cycling the joints and inspecting the microstructure by cross polarizer microscopy and SEM. We found that the addition of small amounts of Pb had significant effects on solidification during cool-down from reflow, and consequently the initial microstructure. In terms of the varying cycling amplitude study, we note how realistic service conditions are almost never well approximated by cycling with fixed amplitudes. Recent results have demonstrated the consistent breakdown of common damage accumulation rules. In isothermal cycling tests the remaining life, after a step-down in amplitude, was invariably shorter than predicted by such a rule, while a step-up tended to have the opposite effect. The present work offers a mechanistic explanation for this and the basis for a practical approach to the assessment of life under service conditions. Realistic BGA joints were cycled individually in a micromechanical tester, monitoring the solder stiffness and the inelastic energy deposition. Cycling was seen to first cause rapid hardening, followed by leveling off in a 'cyclic saturation' stage and eventually the initiation and growth of a crack until failure. A temporary increase in amplitude during cycling caused a lasting reduction in hardness, and thus enhanced inelastic energy deposition and damage evolution, after the fact. This factor dominates during repeated increases and decreases, eventually shortening the remaining life dramatically

Damage mechanisms in alloy 800H under creep-fatigue conditions

NASA Astrophysics Data System (ADS)

Mu, Z.; Bothe, K.; Gerold, V.

1994-05-01

The interaction between fatigue damage (i.e., fatigue crack propagation) and internal grain boundary damage (i.e., cavity formation at grain boundaries) has been studied for the Alloy 800H at 750 C for constant plastic strain ranges but different experimental conditions. Most experiments were performed at constant ranges of alternating tensile/compression stresses. Symmetrical as well as asymmetrical tests (with larger compression stresses) were performed. In comparison to the former tests, asymmetrical tests led to shorter cyclic lifetimes mainly due to cavity formation which was not observed for symmetrical tests. It could be shown that a fast compressive and a slow tensile half cycle (at large compressive and low tensile stresses) are ideal conditions for the nucleation and growth of cavities. Based on quantitative measurements of the cavity density from interrupted fatigue tests, a physical model is presented which can predict the number of cycles to failure. This cycle number is determined only by fatigue crack growth which is controlled by (1) athermal plastic deformation, (2) creep deformation and (3) rate enhancement by cavitation.

High-temperature combustor liner tests in structural component response test facility

NASA Technical Reports Server (NTRS)

Moorhead, Paul E.

1988-01-01

Jet engine combustor liners were tested in the structural component response facility at NASA Lewis. In this facility combustor liners were thermally cycled to simulate a flight envelope of takeoff, cruise, and return to idle. Temperatures were measured with both thermocouples and an infrared thermal imaging system. A conventional stacked-ring louvered combustor liner developed a crack at 1603 cycles. This test was discontinued after 1728 cycles because of distortion of the liner. A segmented or float wall combustor liner tested at the same heat flux showed no significant change after 1600 cycles. Changes are being made in the facility to allow higher temperatures.

Use of anti-mullerian hormone for testing ovarian reserve: a survey of 796 infertility clinics worldwide.

PubMed

Tobler, Kyle J; Shoham, Gon; Christianson, Mindy S; Zhao, Yulian; Leong, Milton; Shoham, Zeev

2015-10-01

The aim of this study is to assess how anti-mullerian hormone (AMH) is used worldwide to test ovarian reserve and guide in vitro fertilization (IVF) cycle management. An internet-based survey was sent electronically to registered IVF providers within the IVF-Worldwide.com network. This survey consisted of nine questions which assessed the clinics' use of AMH. The questionnaire was completed online through the IVF-Worldwide.com website, and quality assurance tools were used to verify that only one survey was completed per clinical IVF center. Results are reported as the proportion of IVF cycles represented by a particular answer choice. Survey responses were completed from 796 globally distributed IVF clinics, representing 593,200 IVF cycles worldwide. Sixty percent of the respondent-IVF cycles reported to use AMH as a first line test, and 54 % reported it as the best test for evaluating ovarian reserve. Eighty-nine percent reported that AMH results were extremely relevant or relevant to clinical practice. However in contrast, for predicting live birth rate, 81 % reported age as the best predictor. AMH is currently considered a first line test for evaluating ovarian reserve and is considered relevant to clinical practice by the majority of IVF providers.

KOH concentration effect on the cycle life of nickel-hydrogen cells. Part 4: Results of failure analyses

NASA Technical Reports Server (NTRS)

Lim, H. S.; Verzwyvelt, S. A.

1989-01-01

KOH concentration effects on cycle life of a Ni/H2 cell have been studied by carrying out a cycle life test of ten Ni/H2 boiler plate cells which contain electrolytes of various KOH concentrations. Failure analyses of these cells were carried out after completion of the life test which accumulated up to 40,000 cycles at an 80 percent depth of discharge over a period of 3.7 years. These failure analyses included studies on changes of electrical characteristics of test cells and component analyses after disassembly of the cell. The component analyses included visual inspections, dimensional changes, capacity measurements of nickel electrodes, scanning electron microscopy, BET surface area measurements, and chemical analyses. Results have indicated that failure mode and change in the nickel electrode varied as the concentration was varied, especially, when the concentration was changed from 31 percent or higher to 26 percent or lower.

Benchmark cyclic plastic notch strain measurements

NASA Technical Reports Server (NTRS)

Sharpe, W. N., Jr.; Ward, M.

1983-01-01

Plastic strains at the roots of notched specimens of Inconel 718 subjected to tension-compression cycling at 650 C are reported. These strains were measured with a laser-based technique over a gage length of 0.1 mm and are intended to serve as 'benchmark' data for further development of experimental, analytical, and computational approaches. The specimens were 250 mm by 2.5 mm in the test section with double notches of 4.9 mm radius subjected to axial loading sufficient to cause yielding at the notch root on the tensile portion of the first cycle. The tests were run for 1000 cycles at 10 cpm or until cracks initiated at the notch root. The experimental techniques are described, and then representative data for the various load spectra are presented. All the data for each cycle of every test are available on floppy disks from NASA.

Clothes Dryer Automatic Termination Evaluation

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

TeGrotenhuis, Ward E.

Volume 2: Improved Sensor and Control Designs Many residential clothes dryers on the market today provide automatic cycles that are intended to stop when the clothes are dry, as determined by the final remaining moisture content (RMC). However, testing of automatic termination cycles has shown that many dryers are susceptible to over-drying of loads, leading to excess energy consumption. In particular, tests performed using the DOE Test Procedure in Appendix D2 of 10 CFR 430 subpart B have shown that as much as 62% of the energy used in a cycle may be from over-drying. Volume 1 of this reportmore » shows an average of 20% excess energy from over-drying when running automatic cycles with various load compositions and dryer settings. Consequently, improving automatic termination sensors and algorithms has the potential for substantial energy savings in the U.S.« less

Benefits for Voice Learning Caused by Concurrent Faces Develop over Time.

PubMed

Zäske, Romi; Mühl, Constanze; Schweinberger, Stefan R

2015-01-01

Recognition of personally familiar voices benefits from the concurrent presentation of the corresponding speakers' faces. This effect of audiovisual integration is most pronounced for voices combined with dynamic articulating faces. However, it is unclear if learning unfamiliar voices also benefits from audiovisual face-voice integration or, alternatively, is hampered by attentional capture of faces, i.e., "face-overshadowing". In six study-test cycles we compared the recognition of newly-learned voices following unimodal voice learning vs. bimodal face-voice learning with either static (Exp. 1) or dynamic articulating faces (Exp. 2). Voice recognition accuracies significantly increased for bimodal learning across study-test cycles while remaining stable for unimodal learning, as reflected in numerical costs of bimodal relative to unimodal voice learning in the first two study-test cycles and benefits in the last two cycles. This was independent of whether faces were static images (Exp. 1) or dynamic videos (Exp. 2). In both experiments, slower reaction times to voices previously studied with faces compared to voices only may result from visual search for faces during memory retrieval. A general decrease of reaction times across study-test cycles suggests facilitated recognition with more speaker repetitions. Overall, our data suggest two simultaneous and opposing mechanisms during bimodal face-voice learning: while attentional capture of faces may initially impede voice learning, audiovisual integration may facilitate it thereafter.

Tensile and Compressive Constitutive Response of 316 Stainless Steel at Elevated Temperatures

NASA Technical Reports Server (NTRS)

Manson, S. S.; Muralidharan, U.; Halford, G. R.

1983-01-01

Creep rate in compression is lower by factors of 2 to 10 than in tension if the microstructure of the two specimens is the same and are tested at equal temperatures and equal but opposite stresses. Such behavior is characteristic for monotonic creep and conditions involving cyclic creep. In the latter case creep rate in both tension and compression progressively increases from cycle to cycle, rendering questionable the possibility of expressing a time stabilized constitutive relationship. The difference in creep rates in tension and compression is considerably reduced if the tension specimen is first subjected to cycles of tensile creep (reversed by compressive plasticity), while the compression specimen is first subjected to cycles of compressive creep (reversed by tensile plasticity). In both cases, the test temperature is the same and the stresses are equal and opposite. Such reduction is a reflection of differences in microstructure of the specimens resulting from different prior mechanical history.

Vapor cycle energy system for implantable circulatory assist devices. Annual progress report, Jul 1975--May 1976

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

Watelet, R.P.; Ruggles, A.E.; Hagen, K.G.

1976-05-01

The development status of a heart assist system driven by a nuclear fueled, electronically controlled vapor cycle engine termed the tidal regenerator engine (TRE) is described. The TRE pressurization is controlled by a torque motor coupled to a displacer. The electrical power for the sensor, electronic logic and actuator is provided by thermoelectric modules interposed between the engine superheater and boiler. The TRE is direct coupled to an assist blood pump which also acts as a blood-cooled heat exchanger, pressure-volume transformer and sensor for the electronic logic. Engine cycle efficiency in excess of 14% has been demonstrated routinely. Overall systemmore » efficiency on 33 watts of over 9% has been demonstrated. A binary version of this engine in the annular configuration is now being tested. The preliminary tests demonstrated 10% cycle efficiency on the first buildup which ran well and started easily.« less

Complete mechanical characterization of an external hexagonal implant connection: in vitro study, 3D FEM, and probabilistic fatigue.

PubMed

Prados-Privado, María; Gehrke, Sérgio A; Rojo, Rosa; Prados-Frutos, Juan Carlos

2018-06-11

The aim of this study was to fully characterize the mechanical behavior of an external hexagonal implant connection (ø3.5 mm, 10-mm length) with an in vitro study, a three-dimensional finite element analysis, and a probabilistic fatigue study. Ten implant-abutment assemblies were randomly divided into two groups, five were subjected to a fracture test to obtain the maximum fracture load, and the remaining were exposed to a fatigue test with 360,000 cycles of 150 ± 10 N. After mechanical cycling, all samples were attached to the torque-testing machine and the removal torque was measured in Newton centimeters. A finite element analysis (FEA) was then executed in ANSYS® to verify all results obtained in the mechanical tests. Finally, due to the randomness of the fatigue phenomenon, a probabilistic fatigue model was computed to obtain the probability of failure associated with each cycle load. FEA demonstrated that the fracture corresponded with a maximum stress of 2454 MPa obtained in the in vitro fracture test. Mean life was verified by the three methods. Results obtained by the FEA, the in vitro test, and the probabilistic approaches were in accordance. Under these conditions, no mechanical etiology failure is expected to occur up to 100,000 cycles. Graphical abstract ᅟ.

Technology development and demonstration of a low thrust resistojet thruster

NASA Technical Reports Server (NTRS)

Pfeifer, G. R.

1972-01-01

Three thrusters were fabricated to definitized thruster drawings using new rhenium vapor deposition technology. Two of the thrusters were operated using ammonia as propellant and one was operated using hydrogen propellant for performance determination. All demonstrated consistent operational specific impulse performance while demonstrating thermal performance better than the development units from which they evolved. Two of the thrusters were subjected to environmental structural testing including vibration, acceleration and shock loading to specifications. Both of the thrusters subjected to the environmental tests passed all required tests. The third, spare, thruster was introduced into the life test portion of the program. Two thrusters were then subjected to a life cycling test program under typical spacecraft operating power levels. During the life test sequence, the hydrogen thruster accrued 720 operating life test cycles, more than 370 on-off cycles and 365 hours of powered up time. The ammonia accrued approximately 380 on-off cycles and 392.2 on time hours of operation during the 720 cycling hour test. Both thrusters completed the scheduled operational life test in reasonably good condition, structurally integral and capable of indefinite further operation.

Effect of perspiration on skin temperature measurements by infrared thermography and contact thermometry during aerobic cycling

NASA Astrophysics Data System (ADS)

Priego Quesada, Jose Ignacio; Martínez Guillamón, Natividad; Cibrián Ortiz de Anda, Rosa M.^a.; Psikuta, Agnes; Annaheim, Simon; Rossi, René Michel; Corberán Salvador, José Miguel; Pérez-Soriano, Pedro; Salvador Palmer, Rosario

2015-09-01

The aim of the present study was to compare infrared thermography and thermal contact sensors for measuring skin temperature during cycling in a moderate environment. Fourteen cyclists performed a 45-min cycling test at 50% of peak power output. Skin temperatures were simultaneously recorded by infrared thermography and thermal contact sensors before and immediately after cycling activity as well as after 10 min cooling-down, representing different skin wetness and blood perfusion states. Additionally, surface temperature during well controlled dry and wet heat exchange (avoiding thermoregulatory responses) using a hot plate system was assessed by infrared thermography and thermal contact sensors. In human trials, the inter-method correlation coefficient was high when measured before cycling (r = 0.92) whereas it was reduced immediately after the cycling (r = 0.82) and after the cooling-down phase (r = 0.59). Immediately after cycling, infrared thermography provided lower temperature values than thermal contact sensors whereas it presented higher temperatures after the cooling-down phase. Comparable results as in human trials were observed for hot plate tests in dry and wet states. Results support the application of infrared thermography for measuring skin temperature in exercise scenarios where perspiration does not form a water film.

40 CFR 86.1506 - Equipment required and specifications; overview.

Code of Federal Regulations, 2014 CFR

2014-07-01

... appear in §§ 86.1509 through 86.1511. (2) Fuel and analytical tests. Fuel requirements for idle exhaust... Natural Gas-Fueled, and Liquefied Petroleum Gas-Fueled Diesel-Cycle Light-Duty Trucks; Idle Test... for performing idle exhaust emission tests on Otto-cycle heavy-duty engines and Otto-cycle light-duty...

Fatigue-environment interactions in a SiC/Ti-15-3 composite

NASA Technical Reports Server (NTRS)

Gayda, J.; Gabb, T. P.; Lerch, B. A.

1993-01-01

Load-controlled isothermal and nonisothermal fatigue lives of a (0-deg)s SiC/Ti-15-3 were evaluated at temperatures between 150 and 550 C and a target strain range of about 0.45 percent. In nonisothermal fatigue tests, load was first cycled at minimum temperature and then temperature was cycled at zero load. For fatigue tests with peak temperatures at or above 300 C, fatigue life was dramatically reduced compared to that at 150 C. The shortest life was produced by the nonisothermal test with the greatest temperature range (Delta T = 400 C) and highest peak temperature (T(max) = 550 C). Vacuum testing showed that much of the life reduction under isothermal and nonisothermal conditions was related to environmental effects, although the nature of the fatigue-environment interaction was decidedly different for the isothermal and nonisothermal test cycles which were studied.

Evaluation program for secondary spacecraft cells: Cycle life test

NASA Technical Reports Server (NTRS)

Harkness, J. D.

1979-01-01

The service life and storage stability for several storage batteries were determined. The batteries included silver-zinc batteries, nickel-cadmium batteries, and silver-cadmium batteries. The cell performance characteristics and limitations are to be used by spacecraft power systems planners and designers. A statistical analysis of the life cycle prediction and cause of failure versus test conditions is presented.

Accelerated Thermal Cycling Test of Microencapsulated Paraffin Wax/Polyaniline Made by Simple Preparation Method for Solar Thermal Energy Storage.

PubMed

Silakhori, Mahyar; Naghavi, Mohammad Sajad; Metselaar, Hendrik Simon Cornelis; Mahlia, Teuku Meurah Indra; Fauzi, Hadi; Mehrali, Mohammad

2013-04-29

Microencapsulated paraffin wax/polyaniline was prepared using a simple in situ polymerization technique, and its performance characteristics were investigated. Weight losses of samples were determined by Thermal Gravimetry Analysis (TGA). The microencapsulated samples with 23% and 49% paraffin showed less decomposition after 330 °C than with higher percentage of paraffin. These samples were then subjected to a thermal cycling test. Thermal properties of microencapsulated paraffin wax were evaluated by Differential Scanning Calorimeter (DSC). Structure stability and compatibility of core and coating materials were also tested by Fourier transform infrared spectrophotometer (FTIR), and the surface morphology of the samples are shown by Field Emission Scanning Electron Microscopy (FESEM). It has been found that the microencapsulated paraffin waxes show little change in the latent heat of fusion and melting temperature after one thousand thermal recycles. Besides, the chemical characteristics and structural profile remained constant after one thousand thermal cycling tests. Therefore, microencapsulated paraffin wax/polyaniline is a stable material that can be used for thermal energy storage systems.

Flat Tile Armour Cooled by Hypervapotron Tube: a Possible Technology for ITER

NASA Astrophysics Data System (ADS)

Schlosser, J.; Escourbiac, F.; Merola, M.; Schedler, B.; Bayetti, P.; Missirlian, M.; Mitteau, R.; Robin-Vastra, I.

Carbon fibre composite (CFC) flat tile armours for actively cooled plasma facing components (PFC’s) are an important challenge for controlled fusion machines. Flat tile concepts, water cooled by tubes, were studied, developed, tested and finally operated with success in Tore Supra. The components were designed for 10 MW/m2 and mock-ups were successfully fatigue tested at 15 MW/m2, 1000 cycles. For ITER, a tube-in-tile concept was developed and mock-ups sustained up to 25 MW/m2 for 1000 cycles without failure. Recently flat tile armoured mock-ups cooled by a hypervapotron tube successfully sustained a cascade failure test under a mean heat flux of 10 MW/m2 but with a doubling of the heat flux on some tiles to simulate missing tiles (500 cycles). This encouraging results lead to reconsider the limits for flat tile concept when cooled by hypervapotron (HV) tube. New tests are now scheduled to investigate these limits in regard to the ITER requirements. Experimental evidence of the concept could be gained in Tore Supra by installing a new limiter into the machine.

Accelerated Thermal Cycling Test of Microencapsulated Paraffin Wax/Polyaniline Made by Simple Preparation Method for Solar Thermal Energy Storage

PubMed Central

Silakhori, Mahyar; Naghavi, Mohammad Sajad; Metselaar, Hendrik Simon Cornelis; Mahlia, Teuku Meurah Indra; Fauzi, Hadi; Mehrali, Mohammad

2013-01-01

Microencapsulated paraffin wax/polyaniline was prepared using a simple in situ polymerization technique, and its performance characteristics were investigated. Weight losses of samples were determined by Thermal Gravimetry Analysis (TGA). The microencapsulated samples with 23% and 49% paraffin showed less decomposition after 330 °C than with higher percentage of paraffin. These samples were then subjected to a thermal cycling test. Thermal properties of microencapsulated paraffin wax were evaluated by Differential Scanning Calorimeter (DSC). Structure stability and compatibility of core and coating materials were also tested by Fourier transform infrared spectrophotometer (FTIR), and the surface morphology of the samples are shown by Field Emission Scanning Electron Microscopy (FESEM). It has been found that the microencapsulated paraffin waxes show little change in the latent heat of fusion and melting temperature after one thousand thermal recycles. Besides, the chemical characteristics and structural profile remained constant after one thousand thermal cycling tests. Therefore, microencapsulated paraffin wax/polyaniline is a stable material that can be used for thermal energy storage systems. PMID:28809232

Experimental transient turbine blade temperatures in a research engine for gas stream temperatures cycling between 1067 and 1567 k

NASA Technical Reports Server (NTRS)

Gauntner, D. J.; Yeh, F. C.

1975-01-01

Experimental transient turbine blade temperatures were obtained from tests conducted on air-cooled blades in a research turbojet engine, cycling between cruise and idle conditions. Transient data were recorded by a high speed data acquisition system. Temperatures at the same phase of each transient cycle were repeatable between cycles to within 3.9 K (7 F). Turbine inlet pressures were repeatable between cycles to within 0.32 N/sq cm (0.47 psia). The tests were conducted at a gas stream temperature of 1567 K (2360 F) at cruise, and 1067 K (1460 F) at idle conditions. The corresponding gas stream pressures were about 26.2 and 22.4 N/sq cm (38 and 32.5 psia) respectively. The nominal coolant inlet temperature was about 811 K (1000 F).

Research, development and demonstration of nickel-iron batteries for electric-vehicle propulsion

NASA Astrophysics Data System (ADS)

1982-03-01

Full-size, prototype cell, module and battery fabrication and evaluation, aimed at advancing the technical capabilities of the nickel-iron battery, while simultaneously reducing its potential cost in materials and process areas are discussed. Improved electroprecipitation process nickel electrodes of design thickness (2.5 mm) are now being prepared that display stable capacities for the C/3 drain rate with less than 10% capacity decline for greater than 1000 test cycles. Iron electrodes of the composite-type are delivering 24 Ah at the target thickness (1.0 mm). Iron electrodes also are displaying capacity stability for greater than 1000 test cycles in continuing 3-plate cell tests. Finished cells delivered 57 to 63 Wh/kg at C/3, and have demonstrated cyclic stability up to 1200 cycles at 80 percent depth of discharge profiles. Modules exceeded 580 test cycles and remain on test. Reduction in nickel electrode swelling (and concurrent stack starvation), to improve cycling, continues to be an area of major effort to reach the final battery cycle life objectives.

40 CFR 86.884-7 - Dynamometer operation cycle for smoke emission tests.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Dynamometer operation cycle for smoke... Dynamometer operation cycle for smoke emission tests. (a) The following sequence of operations shall be... the preconditioning prior to the smoke cycle. (ii) With the throttle remaining in the fully open...

Analysis of Ageing Effect on Li-Polymer Batteries

PubMed Central

Barcellona, Simone; Brenna, Morris; Foiadelli, Federica; Longo, Michela; Piegari, Luigi

2015-01-01

Lithium-ion batteries are a key technology for current and future energy storage in mobile and stationary application. In particular, they play an important role in the electrification of mobility and therefore the battery lifetime prediction is a fundamental aspect for successful market introduction. Numerous studies developed ageing models capable of predicting battery life span. Most of the previous works compared the effect of the ageing factors to a battery's cycle life. These cycles are identical, which is not the case for electric vehicles applications. Indeed, most of the available information is based on results from laboratory testing, under very controlled environments, and using ageing protocols, which may not correctly reflect the actual utilization. For this reason, it is important to link the effect of duty cycles with the ageing of the batteries. This paper proposes a simple method to investigate the effect of the duty cycle on the batteries lifetime through tests performed on different cells for different kinds of cycle. In this way, a generic complex cycle can be seen as a composition of elemental cycles by means of Rainflow procedures. Consequently, the ageing due to any cycle can be estimated starting from the knowledge of simpler cycles. PMID:26236775

Feasibility and safety of extended adjuvant temozolomide beyond six cycles for patients with glioblastoma.

PubMed

Hsieh, S Yp; Chan, D Tm; Kam, M Km; Loong, H Hf; Tsang, W K; Poon, D Mc; Ng, S Cp; Poon, W S

2017-12-01

Temozolomide is the first chemotherapeutic agent proven effective for patients with newly diagnosed glioblastoma. The drug is well tolerated for its low toxicity. The current standard practice is concomitant chemoradiotherapy for 6 weeks followed by 6 cycles of adjuvant temozolomide. Some Caucasian studies have suggested that patients might benefit from extended adjuvant cycles of temozolomide (>6 cycles) to lengthen both progression-free survival and overall survival. In the present study, we compared differences in survival and toxicity profile between patients who received conventional 6-cycle temozolomide and those who received more than 6 cycles of temozolomide. Patients with newly diagnosed glioblastoma without progressive disease and completed concomitant chemoradiotherapy during a 4-year period were studied. Progression-free survival was compared using Kaplan-Meier survival curves. t Test, U test, and correlation were chosen accordingly to examine the impact of age, extent of resection, MGMT promoter methylation status and adjuvant cycles on progression-free survival. For factors with a P value of <0.05 in univariate analyses, Cox regression hazard model was adopted to determine the strongest factors related to progression-free survival. The median progression-free survival was 17.0 months for patients who received 6 cycles of temozolomide (n=7) and 43.4 months for those who received more than 6 cycles (n=7) [P=0.007, log-rank test]. Two patients in the former group and one in the latter group encountered grade 1 toxicity and recovered following dose adjustment. Cycles of adjuvant temozolomide were correlated with progression-free survival (P=0.016, hazard ratio=0.68). Extended cycles of temozolomide are safe and feasible for Chinese patients with disease responsive to temozolomide.

Rapid thermal cycling of solar array blanket coupons for Space Station Freedom

NASA Technical Reports Server (NTRS)

Scheiman, David A.; Smith, Bryan K.

1991-01-01

The NASA Lewis Research Center has been conducting rapid thermal cycling on blanket coupons for Space Station Freedom. This testing includes two designs (8 coupons total) of the solar array. Four coupons were fabricated as part of the Photovoltaic Array Environmental Protection Program (PAEP), NAS3-25079, at Lockheed Missiles and Space Company. These coupons began cycling in early 1989 and have completed 172,000 thermal cycles. Four other coupons were fabricated a year later and included several design changes; cycling of these began in early 1990 and has reached 90,000 cycles. The objective of this testing is to demonstrate the durability or operational lifetime (15 yrs.) of the welded interconnects within a low earth orbit (LEO) thermal cycling environment. The blanket coupons, design changes, test description, status to date including performance and observed anomalies, and any insights related to the testing of these coupons are described. The description of a third design is included.

Effect of Different Phases of Menstrual Cycle on Cardio-respiratory Efficiency in Normal, Overweight and Obese Female Undergraduate Students.

PubMed

Samsudeen, Nazrin; Rajagopalan, Archana

2016-12-01

The influence of obesity on cardio-respiratory efficiency in the various phases of menstrual cycle is not well understood until now. As majority of Indian women have a favourable attitude towards participation in sports it is significant to understand the variation in exercise performance during different phases of menstrual cycle to have an optimum performance. To evaluate the endurance capacity and cardio-respiratory responses in normal, obese and overweight female undergraduate students during different phases of menstrual cycle. Twenty normal weight, 20 obese and 20 over weight, unmarried, undergraduate female volunteers between the age group of 18-22 years, were recruited by convenient sampling. Cardio-respiratory efficiency was assessed by cardiac efficiency test, respiratory endurance test and respiratory blast test. Overall, exercise efficiency varied significantly during the different phases of the menstrual cycle with the highest during luteal phase and lowest during menstrual phase. Similar trend was observed in all the three weight sub-categories, but it was statistically significant in the normal and overweight category only. There was no significant difference in blast test during menstrual phase, follicular phase and luteal phase of menstrual cycle among three groups of individuals. Overall the obese and overweight females had a decreased value for blast test compared to the normal individuals. Significant difference was observed in endurance test among follicular and luteal phase of normal females but there is no change in overweight and obese. Significant difference was observed in Peak Expiratory Flow Rate (PEFR) among luteal phase in normal and overweight individuals but there is no change in obese females. Overall obese individuals have a significant low PEFR compared to normal and overweight individuals. Significant increase in cardiac and respiratory efficiency was observed in the luteal phase of the menstrual cycle in normal weight where as in overweight and obese females, there is an overall decrease in fitness capacity with increase in the Body Mass Index (BMI). Therefore, practice of regular exercise and intake of healthy diet which help in reducing the weight and in turn the BMI will help in enhancing the physical fitness of the individuals.

The physiological and biomechanical differences between double poling and G3 skating in world class cross-country skiers.

PubMed

Sandbakk, Øyvind; Leirdal, Stig; Ettema, Gertjan

2015-03-01

The current study compared differences in cycle characteristics, energy expenditure and peak speed between double poling (DP) and G3 skating. Eight world class male sprint skiers performed a 5-min submaximal test at 16 km h(-1) and an incremental test to exhaustion at a 5% incline during treadmill roller skiing with two different techniques: DP where all propulsion comes from poling, and G3 skating where leg skating is added to each double poling movement. Video analyses determined cycle characteristics; respiratory parameters and blood lactate concentration determined the physiological responses. G3 skating resulted in 16% longer cycle lengths at 16% lower cycle rates, whereas oxygen uptake was independent of technique during submaximal roller skiing. The corresponding advantages for G3 skating during maximal roller skiing were reflected in 14% higher speed, 30% longer cycle length at 16% lower cycle rate and 11% higher peak oxygen uptake (all p < 0.05). Compared to DP approximately 14% higher speed was achieved when leg push-offs were added in G3 skating. This was done by major increases in cycle lengths at slightly lower cycle rates and a higher aerobic energy delivery. However, the oxygen uptake for a given submaximal speed was not affected by technique although higher cycle rate was used in DP.

Experimental Validation of a Closed Brayton Cycle System Transient Simulation

NASA Technical Reports Server (NTRS)

Johnson, Paul K.; Hervol, David S.

2006-01-01

The Brayton Power Conversion Unit (BPCU) is a closed cycle system with an inert gas working fluid. It is located in Vacuum Facility 6 at NASA Glenn Research Center. Was used in previous solar dynamic technology efforts (SDGTD). Modified to its present configuration by replacing the solar receiver with an electrical resistance heater. The first closed-Brayton-cycle to be coupled with an ion propulsion system. Used to examine mechanical dynamic characteristics and responses. The focus of this work was the validation of a computer model of the BPCU. Model was built using the Closed Cycle System Simulation (CCSS) design and analysis tool. Test conditions were then duplicated in CCSS. Various steady-state points. Transients involving changes in shaft rotational speed and heat input. Testing to date has shown that the BPCU is able to generate meaningful, repeatable data that can be used for computer model validation. Results generated by CCSS demonstrated that the model sufficiently reproduced the thermal transients exhibited by the BPCU system. CCSS was also used to match BPCU steady-state operating points. Cycle temperatures were within 4.1% of the data (most were within 1%). Cycle pressures were all within 3.2%. Error in alternator power (as much as 13.5%) was attributed to uncertainties in the compressor and turbine maps and alternator and bearing loss models. The acquired understanding of the BPCU behavior gives useful insight for improvements to be made to the CCSS model as well as ideas for future testing and possible system modifications.

10 CFR Appendix C to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Dishwashers

Code of Federal Regulations, 2013 CFR

2013-01-01

....8Preconditioning cycle means any cycle that includes a fill, circulation, and drain to ensure that the water lines... cycle without a test load if the dishwasher does not heat water in the normal cycle. 2.6.2Non-soil... cycle. 3.4Water pressure gauge. The water pressure gauge must have a resolution of one pound per square...

Facial protection conferred by cycle safety helmets: use of digitized image processing to develop a new nondestructive test.

PubMed

Harrison, M; Shepherd, J P

1997-07-01

Cycle safety helmets are designed to prevent head injury. Although most commercially available helmets conform to one of several national and international standards, individual designs differ widely, particularly in relation to face coverage. A method was developed to assess the potential for the differing designs to protect the face from injury. A nonimpact test was assessed, using digitized image-processing software (Digithurst Ltd.) to measure the shadow cast by a helmet rim under a collimated plane light source onto the face of a mannequin headform. Twelve helmet designs available internationally were tested and ranked with respect to the direct protection conferred (area of the face directly covered by the helmet) and indirect protection (area of the face shaded). The three highest-ranking helmets for direct protection (Rosebank Stackhat, Asphalt Warrior, and Lazer Voyager) also ranked the highest for indirect protection. These helmets were more inferiorly extended and were of a more bulky construction. It was concluded that the dimensions of cycle helmets in relation to face coverage are crucial in influencing the extent to which facial protection is conferred. International test standards need urgent revision to ensure that face coverage is optimized. Lower-face protection could be achieved through incorporation of a lower-face bar to cycle helmets.

Ischemic preconditioning enhances critical power during a 3 minute all-out cycling test.

PubMed

Griffin, Patrick J; Ferguson, Richard A; Gissane, Conor; Bailey, Stephen J; Patterson, Stephen D

2018-05-01

This study tested the hypothesis that ischemic preconditioning (IPC) would increase critical power (CP) during a 3 minute all-out cycling test. Twelve males completed two 3 minute all-out cycling tests, in a crossover design, separated by 7 days. These tests were preceded by IPC (4 x 5 minute intervals at 220 mmHg bilateral leg occlusion) or SHAM treatment (4 x 5 minute intervals at 20 mmHg bilateral leg occlusion). CP was calculated as the mean power output during the final 30 s of the 3 minute test with W' taken as the total work done above CP. Muscle oxygenation was measured throughout the exercise period. There was a 15.3 ± 0.3% decrease in muscle oxygenation (TSI; [Tissue saturation index]) during the IPC stimulus, relative to SHAM. CP was significantly increased (241 ± 65 W vs. 234 ± 67 W), whereas W' (18.4 ± 3.8 vs 17.9 ± 3.7 kJ) and total work done (TWD) were not different (61.1 ± 12.7 vs 60.8 ± 12.7 kJ), between the IPC and SHAM trials. IPC enhanced CP during a 3 minute all-out cycling test without impacting W' or TWD. The improved CP after IPC might contribute towards the effect of IPC on endurance performance.

Two pilot studies of the effect of bicycling on balance and leg strength among older adults.

PubMed

Rissel, Chris; Passmore, Erin; Mason, Chloe; Merom, Dafna

2013-01-01

Study 1 examines whether age-related declines in balance are moderated by bicycling. Study 2 tests whether regular cycling can increase leg strength and improve balance. Study 1: a cross-sectional survey of 43 adults aged 44-79 was conducted. Leg strength was measured, and Balance was measured using the choice stepping reaction time (CSRT) test (decision time and response time), leg strength and timed single leg standing. Study 2: 18 older adults aged 49-72 were recruited into a 12-week cycling program. The same pre- and postmeasures as used in Study 1 were collected. Study 1: participants who had cycled in the last month performed significantly better on measures of decision time and response time. Study 2: cycling at least one hour a week was associated with significant improvements in balance (decision time and response time) and timed single leg standing. Cycling by healthy older adults appears promising for improving risk factors for falls.

Two Pilot Studies of the Effect of Bicycling on Balance and Leg Strength among Older Adults

PubMed Central

Rissel, Chris; Passmore, Erin; Mason, Chloe; Merom, Dafna

2013-01-01

Objectives. Study 1 examines whether age-related declines in balance are moderated by bicycling. Study 2 tests whether regular cycling can increase leg strength and improve balance. Methods. Study 1: a cross-sectional survey of 43 adults aged 44–79 was conducted. Leg strength was measured, and Balance was measured using the choice stepping reaction time (CSRT) test (decision time and response time), leg strength and timed single leg standing. Study 2: 18 older adults aged 49–72 were recruited into a 12-week cycling program. The same pre- and postmeasures as used in Study 1 were collected. Results. Study 1: participants who had cycled in the last month performed significantly better on measures of decision time and response time. Study 2: cycling at least one hour a week was associated with significant improvements in balance (decision time and response time) and timed single leg standing. Conclusions. Cycling by healthy older adults appears promising for improving risk factors for falls. PMID:23690805

Long life nickel electrodes for a nickel-hydrogen cell: Cycle life tests

NASA Technical Reports Server (NTRS)

Lim, H. S.; Verzwyvelt, S. A.

1985-01-01

In order to develop a long life nickel electrode for a Ni/H2 cell, the cycle life of nickel electrodes was tested in Ni/H2 boiler plate cells. A 19 test cell matrix was made of various nickel electrode designs including three levels each of plaque mechanical strength, median pore size of the plaque, and active material loading. Test cells were cycled to the end of their life (0.5v) in a 45 minute low Earth orbit cycle regime at 80% depth-of-discharge. It is shown that the active material loading level affects the cycle life the most with the optimum loading at 1.6 g/cc void. Mechanical strength does not affect the cycle life noticeably in the bend strength range of 400 to 700 psi. It is found that the best plaque is made of INCO nickel powder type 287 and has median pore size of 13 micron.

Increasing the volumetric efficiency of Diesel engines by intake pipes

NASA Technical Reports Server (NTRS)

List, Hans

1933-01-01

Development of a method for calculating the volumetric efficiency of piston engines with intake pipes. Application of this method to the scavenging pumps of two-stroke-cycle engines with crankcase scavenging and to four-stroke-cycle engines. The utility of the method is demonstrated by volumetric-efficiency tests of the two-stroke-cycle engines with crankcase scavenging. Its practical application to the calculation of intake pipes is illustrated by example.

Validation test of 125 Ah advanced design IPV nickel-hydrogen flight cells

NASA Technical Reports Server (NTRS)

Smithrick, John J.; Hall, Stephen W.

1993-01-01

An update of validation test results confirming the advanced design nickel-hydrogen cell is presented. An advanced 125 Ah individual pressure vessel (IPV) nickel-hydrogen cell was designed. The primary function of the advanced cell is to store and deliver energy for long-term, Low-Earth-Orbit (LEO) spacecraft missions. The new features of this design, which are not incorporated in state-of-the-art design cells, are: (1) use of 26 percent rather than 31 percent potassium hydroxide (KOH) electrolyte; (2) use of a patented catalyzed wall wick; (3) use of serrated-edge separators to facilitate gaseous oxygen and hydrogen flow within the cell, while still maintaining physical contact with the wall wick for electrolyte management; and (4) use of a floating rather than a fixed stack (state-of-the-art) to accommodate nickel electrode expansion due to charge/discharge cycling. The significant improvements resulting from these innovations are extended cycle life; enhanced thermal, electrolyte, and oxygen management; and accommodation of nickel electrode expansion. Six 125 Ah flight cells based on this design were fabricated by Eagle-Picher. Three of the cells contain all of the advanced features (test cells) and three are the same as the test cells except they do not have catalyst on the wall wick (control cells). All six cells are in the process of being evaluated in a LEO cycle life test at the Naval Weapons Support Center, Crane, IN, under a NASA Lewis Research Center contract. The catalyzed wall wick cells have been cycled for over 19000 cycles with no cell failures in the continuing test. Two of the noncatalyzed wall wick cells failed (cycles 9588 and 13,900).

Influence of the Conditioning Method for Pre-Sintered Zirconia on the Shear Bond Strength of Bilayered Porcelain/Zirconia

PubMed Central

Spintzyk, Sebastian; Yamaguchi, Kikue; Sawada, Tomofumi; Schille, Christine; Schweizer, Ernst; Ozeki, Masahiko; Geis-Gerstorfer, Jürgen

2016-01-01

This study evaluated the bond strength of veneering porcelain with an experimental conditioner-coated zirconia. Pre-sintered Y-TZP specimens (n = 44) were divided in two groups based on conditioning type. After sintering, all sample surfaces were sandblasted and layered with veneering porcelain. Additionally, half of the specimens in each group underwent thermal cycling (10,000 cycles, 5–55 °C), and all shear bond strengths were measured. After testing, the failure mode of each fractured specimen was determined. Differences were tested by parametric and Fisher’s exact tests (α = 0.05). The differences in bond strength were not statistically significant. Adhesive fractures were dominantly observed for the non-thermal cycled specimens. After thermal cycling, the conditioner-coated group showed cohesive and mixed fractures (p = 0.0021), whereas the uncoated group showed more adhesive fractures (p = 0.0021). Conditioning of the pre-sintered Y-TZP did not change the shear bond strength of the veneering porcelain, but did improve the failure mode after thermal cycling. PMID:28773885

Elevated Temperature Fatigue Endurance of Three Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Kalluri, Sreeramesh; Verrilli, Michael J.

2007-01-01

High-cycle fatigue endurance of three candidate materials for the acoustic liners of the Enabling Propulsion Materials Nozzle Program was investigated. The ceramic matrix composite materials investigated were N720/AS (Nextel 720, 3M Corporation), Sylramic S200 (Dow Corning), and UT 22. High-cycle fatigue tests were conducted in air at 910 C on as-machined specimens and on specimens subjected to tensile cyclic load excursions every 160 hr followed by thermal exposure at 910 C in a furnace up to total exposure times of 2066 and 4000 hr. All the fatigue tests were conducted in air at 100 Hz with a servohydraulic test machine. In the as-machined condition, among the three materials investigated only the Sylramic S200 exhibited a deterministic type of high-cycle fatigue behavior. Both the N720/AS and UT-22 exhibited significant scatter in the experimentally observed high-cycle fatigue lives. Among the thermally exposed specimens, N720/AS and Sylramic S200 materials exhibited a reduction in the high-cycle fatigue lives, particularly at the exposure time of 4000 hr.

PACS: acceptance test, quality control, warranty, and maintenance continuum

NASA Astrophysics Data System (ADS)

Romlein, John R.; Norton, Gary S.; Lyche, David K.; Richardson, Ronald R., Jr.

1999-07-01

As PACS gain greater acceptance and use in medical facilities the question of life cycle management must be addressed in terms that relate to the common business practices for medical information system and medical devices. The issues in life cycle management of such a system are relatively new to the industry. Increased use of PACS within the medical community requires that standardized life cycle management practices by developed and implemented. This paper develops a new of life cycle issues as cyclic and related events that are not only manageable, but also predictable in terms, of, frequency, duration data content, data exchange, potential outcomes, staffing requirement, documentation, and staff interaction. This view is presented as a continuum that begins at the acceptance testing of a PACS and continues throughout its life cycle. The continuum incorporates the required relationship between quality control testing and maintenance actions during warranty period and the maintenance years. Interrelated cyclic events are described that bind these processes together and provide a basis for long-term proactive management of PACS in a medical environment.

Crack Initiation and Growth Behavior at Corrosion Pit in 2024-T3 Aluminum Alloy

DTIC Science & Technology

2014-09-01

63 Figure B.1: The crack length vs. number of cycles during fatigue testing for the 2AI-01 specimen...number of cycles during fatigue testing for the the 2AI- 02 specimen...64 Figure B.3: The crack length vs. number of cycles during fatigue testing for the 2Sl-01 specimen

Evaluation of 20 Ah Li Ion Cells

NASA Technical Reports Server (NTRS)

Smart, Marshall; Ratnakumar, B. V.; Huang, Charles K.; Surampudi, S.; Hill, Carole; Radzykewycz, Dan T.; Marsh, Richard A.

1998-01-01

Lithium ion cells of 20 Ah capacity were fabricated by Bluestar Advanced Technology Corporation, Canada under a developmental contract from US Air Force. In this paper, we report our studies on the evaluation of these cells under various test conditions. These include generic test conditions such as discharges and charges at different temperatures to understand the rate-limiting processes in the discharge/charge processes as a function of temperature, and cycle life under standard cycling conditions (100% DOD) at ambient temperature. In addition, tests are being done to ascertain the performance of the cells in the Mars 2001 Lander application, which includes pulse testing of the cells at 60 A and 40 A loads for 100 mS and 1 min., respectively at different states of charge and temperatures, and cycling at low temperature at partial depths of discharge.

Testing of sealed lead-acid batteries

NASA Astrophysics Data System (ADS)

Bush, D. M.; Sealey, J. D.; Miller, D. W.

1984-02-01

Sealed lead acid batteries under development were tested. The goal was to develop a totally maintenance free sealed lead acid battery capable of deep discharge operation in a photovoltaic power system. Sealed lead acid batteries and a group of conventional, flooded lead acid batteries were exposed to a matrix test plan, with some approaching 1000 cycles. This performance was achieved with the standard National Electrical Manufacturers' Association cycle test, and the partial state of charge cycle test. Modes of failure are investigated.

Accelerated Thermal Cycling and Failure Mechanisms

NASA Technical Reports Server (NTRS)

Ghaffarian, R.

1999-01-01

This paper reviews the accelerated thermal cycling test methods that are currently used by industry to characterize the interconnect reliability of commercial-off-the-shelf (COTS) ball grid array (BGA) and chip scale package (CSP) assemblies.

Genome scale engineering techniques for metabolic engineering.

PubMed

Liu, Rongming; Bassalo, Marcelo C; Zeitoun, Ramsey I; Gill, Ryan T

2015-11-01

Metabolic engineering has expanded from a focus on designs requiring a small number of genetic modifications to increasingly complex designs driven by advances in genome-scale engineering technologies. Metabolic engineering has been generally defined by the use of iterative cycles of rational genome modifications, strain analysis and characterization, and a synthesis step that fuels additional hypothesis generation. This cycle mirrors the Design-Build-Test-Learn cycle followed throughout various engineering fields that has recently become a defining aspect of synthetic biology. This review will attempt to summarize recent genome-scale design, build, test, and learn technologies and relate their use to a range of metabolic engineering applications. Copyright © 2015 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

High-Cycle Fatigue Resistance of Si-Mo Ductile Cast Iron as Affected by Temperature and Strain Rate

NASA Astrophysics Data System (ADS)

Matteis, Paolo; Scavino, Giorgio; Castello, Alessandro; Firrao, Donato

2015-09-01

Silicon-molybdenum ductile cast irons are used to fabricate exhaust manifolds of internal combustion engines of large series cars, where the maximum pointwise temperature at full engine load may be higher than 973 K (700 °C). In this application, high-temperature oxidation and thermo-mechanical fatigue (the latter being caused by the engine start and stop and by the variation of its power output) have been the subject of several studies and are well known, whereas little attention has been devoted to the high-cycle fatigue, arising from the engine vibration. Therefore, the mechanical behavior of Si-Mo cast iron is studied here by means of stress-life fatigue tests up to 10 million cycles, at temperatures gradually increasing up to 973 K (700 °C). The mechanical characterization is completed by tensile and compressive tests and ensuing fractographic examinations; the mechanical test results are correlated with the cast iron microstructure and heat treatment.

High-durability catalytic electrode composed of Pt nanoparticle-supported carbon nanowalls synthesized by radical-injection plasma-enhanced chemical vapor deposition

NASA Astrophysics Data System (ADS)

Imai, Shun; Kondo, Hiroki; Cho, Hyungjun; Kano, Hiroyuki; Ishikawa, Kenji; Sekine, Makoto; Hiramatsu, Mineo; Ito, Masafumi; Hori, Masaru

2017-10-01

For polymer electrolyte fuel cell applications, carbon nanowalls (CNWs) were synthesized by radical-injection plasma-enhanced chemical vapor deposition, and a high density of Pt nanoparticles (>1012 cm-2) was supported on the CNWs using a supercritical fluid deposition system. The high potential cycle tests were applied and the electrochemical surface area of the Pt nanoparticle-supported CNWs did not change significantly, even after 20 000 high potential cycles. According to transmission electron microscopy observations, the mean diameter of Pt changed slightly after the cycle tests, while the crystallinity of the CNWs evaluated using Raman spectroscopy showed almost no change.

Individual Pressure Vessel (PV) and Common Pressure Vessel (CPV) Nickel-Hydrogen Battery Performance Under LEO Cycling Conditions

NASA Technical Reports Server (NTRS)

Miller, Thomas B.; Lewis, Harlan L.

2004-01-01

LEO life cycle testing of Individual Pressure Vessel (PV) and Common Pressure Vessel (CPV) nickel-hydrogen cell packs have been sponsored by the NASA Aerospace Flight Battery Program. The cell packs have cycled under both 35% and 60% depth-of- discharge and temperature conditions of -5 C and +lO C. The packs have been on test since as early as 1992 and have generated a substantial database. This report will provide insight into performance trends as a function of the specific cell configuration and manufacturer for eight separate nickel-hydrogen battery cell packs.

Successful completion of a cyclic ground test of a mercury ion auxiliary propulsion system

NASA Technical Reports Server (NTRS)

Francisco, David R.; Low, Charles A., Jr.; Power, John L.

1988-01-01

An engineering model Ion Auxiliary Propulsion System (IAPS) 8-cm thruster (S/N 905) has completed a life test at NASA Lewis Research Center. The mercury ion thruster successfully completed and exceeded the test goals of 2557 on/off cycles and 7057 hr of operation at full thrust. The final 1200 cycles and 3600 hr of the life test were conducted using an engineering model of the IAPS power electronics unit (PEU) and breadboard digital controller and interface unit (DCIU). This portion of the test is described in this paper with a charted history of thruster operating parameters and off-normal events. Performance and operating characteristics were constant throughout the test with only minor variations. The engineering model power electronics unit operated without malfunction; the flight software in the digital controller and interface unit was exercised and verified. Post-test inspection of the thruster revealed facility enhanced accelerator grid erosion but overall the thruster was in good condition. It was concluded that the thruster performance was not drastically degraded by time or cycles. Additional cyclic testing is currently under consideration.

Successful completion of a cyclic ground test of a mercury Ion Auxiliary Propulsion System

NASA Technical Reports Server (NTRS)

Francisco, David R.; Low, Charles A., Jr.; Power, John L.

1988-01-01

An engineering model Ion Auxiliary Propulsion System (IAPS) 8-cm thruster (S/N 905) has completed a life test at NASA Lewis Research Center. The mercury ion thruster successfully completed and exceeded the test goals of 2557 on/off cycles and 7057 hr of operation at full thrust. The final 1200 cycles and 3600 hr of the life test were conducted using an engineering model of the IAPS power electronics unit (PEU) and breadboard digital controller and interface unit (DCIU). This portion of the test is described in this paper with a charted history of thruster operating parameters and off-normal events. Performance and operating characteristics were constant throughout the test with only minor variations. The engineering model power electronics unit operated without malfunction; the flight software in the digital controller and interface unit was exercised and verified. Post-test inspection of the thruster revealed facility enhanced accelerator grid erosion but overall the thruster was in good condition. It was concluded that the thruster performance was not drastically degraded by time or cycles. Additional cyclic testing is currently under consideration.

Homogeneity tests of clustered diagnostic markers with applications to the BioCycle Study

PubMed Central

Tang, Liansheng Larry; Liu, Aiyi; Schisterman, Enrique F.; Zhou, Xiao-Hua; Liu, Catherine Chun-ling

2014-01-01

Diagnostic trials often require the use of a homogeneity test among several markers. Such a test may be necessary to determine the power both during the design phase and in the initial analysis stage. However, no formal method is available for the power and sample size calculation when the number of markers is greater than two and marker measurements are clustered in subjects. This article presents two procedures for testing the accuracy among clustered diagnostic markers. The first procedure is a test of homogeneity among continuous markers based on a global null hypothesis of the same accuracy. The result under the alternative provides the explicit distribution for the power and sample size calculation. The second procedure is a simultaneous pairwise comparison test based on weighted areas under the receiver operating characteristic curves. This test is particularly useful if a global difference among markers is found by the homogeneity test. We apply our procedures to the BioCycle Study designed to assess and compare the accuracy of hormone and oxidative stress markers in distinguishing women with ovulatory menstrual cycles from those without. PMID:22733707

Cycling induced by electrical stimulation improves muscle activation and symmetry during pedaling in hemiparetic patients.

PubMed

Ambrosini, Emilia; Ferrante, Simona; Ferrigno, Giancarlo; Molteni, Franco; Pedrocchi, Alessandra

2012-05-01

A randomized controlled trial, involving 35 post-acute hemiparetic patients, demonstrated that a four-week treatment of cycling induced by functional electrical stimulation (FES-cycling) promotes motor recovery. Analyzing additional data acquired during that study, the present work investigated whether these improvements were associated to changes in muscle strength and motor coordination. Participants were randomized to receive FES-cycling or placebo FES-cycling. Clinical outcome measures were: the Motricity Index (MI), the gait speed, the electromyography activation of the rectus femoris and biceps femoris, and the mechanical work produced by each leg during voluntary pedaling. To provide a comparison with normal values, healthy adults also carried out the pedaling test. Patients were evaluated before, after training, and at follow-up visits. A significant treatment effect in favor of FES-treated patients was found in terms of MI scores and unbalance in mechanical works, while differences in gait speed were not significant (ANCOVA). Significant improvements in the activation of the paretic muscles were highlighted in the FES group, while no significant change was found in the placebo group (Friedman test). Our findings suggested that improvements in motor functions induced by FES-cycling training were associated with a more symmetrical involvement of the two legs and an improved motor coordination.

A Stochastic Model of the Yeast Cell Cycle Reveals Roles for Feedback Regulation in Limiting Cellular Variability.

PubMed

Barik, Debashis; Ball, David A; Peccoud, Jean; Tyson, John J

2016-12-01

The cell division cycle of eukaryotes is governed by a complex network of cyclin-dependent protein kinases (CDKs) and auxiliary proteins that govern CDK activities. The control system must function reliably in the context of molecular noise that is inevitable in tiny yeast cells, because mistakes in sequencing cell cycle events are detrimental or fatal to the cell or its progeny. To assess the effects of noise on cell cycle progression requires not only extensive, quantitative, experimental measurements of cellular heterogeneity but also comprehensive, accurate, mathematical models of stochastic fluctuations in the CDK control system. In this paper we provide a stochastic model of the budding yeast cell cycle that accurately accounts for the variable phenotypes of wild-type cells and more than 20 mutant yeast strains simulated in different growth conditions. We specifically tested the role of feedback regulations mediated by G1- and SG2M-phase cyclins to minimize the noise in cell cycle progression. Details of the model are informed and tested by quantitative measurements (by fluorescence in situ hybridization) of the joint distributions of mRNA populations in yeast cells. We use the model to predict the phenotypes of ~30 mutant yeast strains that have not yet been characterized experimentally.

A Stochastic Model of the Yeast Cell Cycle Reveals Roles for Feedback Regulation in Limiting Cellular Variability

PubMed Central

Ball, David A.

2016-01-01

The cell division cycle of eukaryotes is governed by a complex network of cyclin-dependent protein kinases (CDKs) and auxiliary proteins that govern CDK activities. The control system must function reliably in the context of molecular noise that is inevitable in tiny yeast cells, because mistakes in sequencing cell cycle events are detrimental or fatal to the cell or its progeny. To assess the effects of noise on cell cycle progression requires not only extensive, quantitative, experimental measurements of cellular heterogeneity but also comprehensive, accurate, mathematical models of stochastic fluctuations in the CDK control system. In this paper we provide a stochastic model of the budding yeast cell cycle that accurately accounts for the variable phenotypes of wild-type cells and more than 20 mutant yeast strains simulated in different growth conditions. We specifically tested the role of feedback regulations mediated by G1- and SG2M-phase cyclins to minimize the noise in cell cycle progression. Details of the model are informed and tested by quantitative measurements (by fluorescence in situ hybridization) of the joint distributions of mRNA populations in yeast cells. We use the model to predict the phenotypes of ~30 mutant yeast strains that have not yet been characterized experimentally. PMID:27935947

Microstructure: Property correlation. [multiaxial fatigue damage evolution in waspaloy

NASA Technical Reports Server (NTRS)

Jayaraman, N.

1990-01-01

Strain controlled torsional and biaxial (tension-torsion) low cycle fatigue behavior of Waspaloy was studied at room temperature as a function of heat treatment. Biaxial tests were conducted under proportional (when the axial and torsional strain cycles are in-phase) and non-proportional (when the axial and torsional strain cycles are 90 deg out-of-phase) cyclic conditions. The deformation behavior under these different cyclic conditions were evaluated by slip trace analysis. For this, a Schmidt-type factor was defined for multiaxial loading conditions and it was shown that when the slip deformation is predominant, non-proportional cycles are more damaging than proportional or pure axial or torsional cycles. This was attributed to the fact that under non-proportional cyclic conditions, deformation was through multiple slip as opposed single slip for other loading conditions, which gave rise to increased hardening. The total life for a given test condition was found to be independent of heat treatment. This was interpreted as being due to the differences in the cycles to initiation and propagation of cracks.

Experiment and Modeling of Simultaneous Creep, Plasticity and Transformation of High Temperature Shape Memory Alloys During Cyclic Actuation

NASA Technical Reports Server (NTRS)

Kumar, Parikshith K.; Desai, Uri; Chatzigeorgiou, George; Lagoudas, Dimitris C.; Monroe, James; Karaman, Ibrahim; Noebe, Ron; Bigelow, Glen

2010-01-01

The present work is focused on studying the cycling actuation behavior of HTSMAs undergoing simultaneous creep and transformation. For the thermomechanical testing, a high temperature test setup was assembled on a MTS frame with the capability to test up to temperatures of 600 C. Constant stress thermal cycling tests were conducted to establish the actuation characteristics and the phase diagram for the chosen HTSMA. Additionally, creep tests were conducted at constant stress levels at different test temperatures to characterize the creep behavior of the alloy over the operational range. A thermodynamic constitutive model is developed and extended to take into account a) the effect of multiple thermal cycling on the generation of plastic strains due to transformation (TRIP strains) and b) both primary and secondary creep effects. The model calibration is based on the test results. The creep tests and the uniaxial tests are used to identify the viscoplastic behavior of the material. The parameters for the SMA properties, regarding the transformation and transformation induced plastic strain evolutions, are obtained from the material phase diagram and the thermomechanical tests. The model is validated by predicting the material behavior at different thermomechanical test conditions.

Radiation Analysis Program

DTIC Science & Technology

2018-02-28

qualification testing to include vibrational, thermal bake and thermal cycling to ensure the experiment would perform as expected during operation on...series of tests for flight qualification. These tests included bake and thermal cycling. In addition, vibrational testing was also accomplished

An experimental study on pseudoelasticity of a NiTi-based damper for civil applications

NASA Astrophysics Data System (ADS)

Nespoli, Adelaide; Bassani, Enrico; Della Torre, Davide; Donnini, Riccardo; Villa, Elena; Passaretti, Francesca

2017-10-01

In this work, a pseudoelastic damper composed by NiTi wires is tested at 0.5, 1 and 2 Hz for 1000 mechanical cycles. The damping performances were evaluated by three key parameters: the damping capacity, the dissipated energy per cycle and the maximum force. During testing, the temperature of the pseudoelastic elements was registered as well. Results show that the damper assures a bi-directional motion throughout the 1000 cycles together with the maintenance of the recentering. It was observed a stabilization process in the first 50 mechanical cycles, where the key parameters reach stable values; in particular it was found that the damping capacity and the dissipated energy both decrease with frequency. Besides, the mean temperature of the pseudoleastic elements reaches a stable value during tests and confirms the different response of the pseudoelastic wires accordingly with the specific length and stain. Finally, interesting thermal effects were observed at 1 and 2 Hz: at these frequencies and at high strains, the maximum force increases but the temperature of the NiTi wire decreases being in contraddiction with the Clausius-Clapeyron law.

The increase in fatigue crack growth rates observed for Zircaloy-4 in a PWR environment

NASA Astrophysics Data System (ADS)

Cockeram, B. V.; Kammenzind, B. F.

2018-02-01

Cyclic stresses produced during the operation of nuclear reactors can result in the extension of cracks by processes of fatigue. Although fatigue crack growth rate (FCGR) data for Zircaloy-4 in air are available, little testing has been performed in a PWR primary water environment. Test programs have been performed by Gee et al., in 1989 and Picker and Pickles in 1984 by the UK Atomic Energy Authority, and by Wisner et al., in 1994, that have shown an enhancement in FCGR for Zircaloy-2 and Zircaloy-4 in high-temperature water. In this work, FCGR testing is performed on Zircaloy-4 in a PWR environment in the hydrided and non-hydrided condition over a range of stress-intensity. Measurements of crack extension are performed using a direct current potential drop (DCPD) method. The cyclic rate in the PWR primary water environment is varied between 1 cycle per minute to 0.1 cycle per minute. Faster FCGR rates are observed in water in comparison to FCGR testing performed in air for the hydrided material. Hydrided and non-hydrided materials had similar FCGR values in air, but the non-hydrided material exhibited much lower rates of FCGR in a PWR primary water environment than for hydrided material. Hydrides are shown to exhibit an increased tendency for cracking or decohesion in a PWR primary water environment that results in an enhancement in FCGR values. The FCGR in the PWR primary water only increased slightly with decreasing cycle frequency in the range of 1 cycle per minute to 0.1 cycle per minute. Comparisons between the FCGR in water and air show the enhancement from the PWR environment is affected by the applied stress intensity.

An Update on the Lithium-Ion Cell Low-Earth-Orbit Verification Test Program

NASA Technical Reports Server (NTRS)

Reid, Concha M.; Manzo, Michelle A.; Miller, Thomas B.; McKissock, Barbara I.; Bennett, William

2007-01-01

A Lithium-Ion Cell Low-Earth-Orbit Verification Test Program is being conducted by NASA Glenn Research Center to assess the performance of lithium-ion (Li-ion) cells over a wide range of low-Earth-orbit (LEO) conditions. The data generated will be used to build an empirical model for Li-ion batteries. The goal of the modeling will be to develop a tool to predict the performance and cycle life of Li-ion batteries operating at a specified set of mission conditions. Using this tool, mission planners will be able to design operation points of the battery system while factoring in mission requirements and the expected life and performance of the batteries. Test conditions for the program were selected via a statistical design of experiments to span a range of feasible operational conditions for LEO aerospace applications. The variables under evaluation are temperature, depth-of-discharge (DOD), and end-of-charge voltage (EOCV). The baseline matrix was formed by generating combinations from a set of three values for each variable. Temperature values are 10 C, 20 C and 30 C. Depth-of-discharge values are 20%, 30% and 40%. EOCV values are 3.85 V, 3.95 V, and 4.05 V. Test conditions for individual cells may vary slightly from the baseline test matrix depending upon the cell manufacturer s recommended operating conditions. Cells from each vendor are being evaluated at each of ten sets of test conditions. Cells from four cell manufacturers are undergoing life cycle tests. Life cycling on the first sets of cells began in September 2004. These cells consist of Saft 40 ampere-hour (Ah) cells and Lith ion 30 Ah cells. These cells have achieved over 10,000 cycles each, equivalent to about 20 months in LEO. In the past year, the test program has expanded to include the evaluation of Mine Safety Appliances (MSA) 50 Ah cells and ABSL battery modules. The MSA cells will begin life cycling in October 2006. The ABSL battery modules consist of commercial Sony hard carbon 18650 lithium-ion cells configured in series and parallel combinations to create nominal 14.4 volt, 3 Ah packs (4s-2p). These modules have accumulated approximately 3000 cycles. Results on the performance of the cells and modules will be presented in this paper. The life prediction and performance model for Li-ion cells in LEO will be built by analyzing the data statistically and performing regression analysis. Cells are being cycled to failure so that differences in performance trends that occur at different stages in the life of the cell can be observed and accurately modeled. Cell testing is being performed at the Naval Surface Warfare Center in Crane, IN.

Creep-fatigue of low cobalt superalloys

NASA Technical Reports Server (NTRS)

Halford, G. R.

1982-01-01

Testing for the low cycle fatigue and creep fatigue resistance of superalloys containing reduced amounts of cobalt is described. The test matrix employed involves a single high temperature appropriate for each alloy. A single total strain range, again appropriate to each alloy, is used in conducting strain controlled, low cycle, creep fatigue tests. The total strain range is based upon the level of straining that results in about 10,000 cycles to failure in a high frequency (0.5 Hz) continuous strain-cycling fatigue test. No creep is expected to occur in such a test. To bracket the influence of creep on the cyclic strain resistance, strain hold time tests with ore minute hold periods are introduced. One test per composition is conducted with the hold period in tension only, one in compression only, and one in both tension and compression. The test temperatures, alloys, and their cobalt compositions that are under study are given.

Effect of Thermal Cycling on the Tensile Behavior of Polymer Composites Reinforced by Basalt and Carbon Fibers

NASA Astrophysics Data System (ADS)

Khalili, S. Mohammad Reza; Najafi, Moslem; Eslami-Farsani, Reza

2017-01-01

The aim of the present work was to investigate the effect of thermal cycling on the tensile behavior of three types of polymer-matrix composites — a phenolic resin reinforced with woven basalt fibers, woven carbon fibers, and hybrid basalt and carbon fibers — in an ambient environment. For this purpose, tensile tests were performed on specimens previously subjected to a certain number of thermal cycles. The ultimate tensile strength of the specimen reinforced with woven basalt fibers had by 5% after thermal cycling, but the strength of the specimen with woven carbon fibers had reduced to a value by 11% higher than that before thermal cycling.

No effect of weight cycling on the post-career BMI of weight class elite athletes

PubMed Central

2013-01-01

Background Repetitions of pre-competition weight-loss diets done by athletes participating in weight class sports can be regarded as periods of weight cycling. The aim of the present study is to identify the long term post-career (22 years) evolutionary profile of athletes’ BMI after such weight cycling. Methods One hundred and thirty-six retired French athletes who participated in major international competitions in weight class sports (rowers, wrestlers, boxers, and judokas) were included. Former and current body mass, height, dietary characteristics during the career (annual frequency, amount of weight lost), current physical activity, and answers on the eating-attitude test were collected by phone interview (consistency was tested by comparison with measured weight). We performed ANOVA tests for comparison between groups (sport, dieting), post-hoc tests (Bonferroni test) to identify differences within groups. BMI’s changes were treated using a mixed model. Results The recorded weight changes did not depend upon time since retirement. Between 18 y and 50 y, athletes’ BMI increased by 3.2 kg/m2 compared to the 4.2 kg/m2 increase in the general population. This increase was independent of the number of diets during the career. Retired athletes declared a mean weekly physical activity of 4.8 h ± 4.3. The eating-attitude test showed low scores for all sports without any correlation to diet characteristics. Conclusion Weight cycling during an athletic career does not induce a massive weight gain after retirement, probably due to the high level of physical activity still practiced after retirement by these athletes. PMID:23711106

Manufacturing and testing of a prototypical divertor vertical target for ITER

NASA Astrophysics Data System (ADS)

Merola, M.; Plöchl, L.; Chappuis, Ph; Escourbiac, F.; Grattarola, M.; Smid, I.; Tivey, R.; Vieider, G.

2000-12-01

After an extensive R&D activity, a medium-scale divertor vertical target prototype has been manufactured by the EU Home Team. This component contains all the main features of the corresponding ITER divertor design and consists of two units with one cooling channel each, assembled together and having an overall length and width of about 600 and 50 mm, respectively. The upper part of the prototype has a tungsten macro-brush armour, whereas the lower part is covered by CFC monoblocks. A number of joining techniques were required to manufacture this component as well as an appreciable effort in the development of suitable non-destructive testing methods. The component was high heat flux tested in FE200 electron beam facility at Le Creusot, France. It endured 100 cycles at 5 MW/m 2, 1000 cycles at 10 MW/m 2 and more then 1000 cycles at 15-20 MW/m 2. The final critical heat flux test reached a value in excess of 30 MW/m 2.

Acoustic emission testing of 12-nickel maraging steel pressure vessels

NASA Technical Reports Server (NTRS)

Dunegan, H. L.

1973-01-01

Acoustic emission data were obtained from three point bend fracture toughness specimens of 12-nickel maraging steel, and two pressure vessels of the same material. One of the pressure vessels contained a prefabricated flaw which was extended and sharpened by fatigue cycling. It is shown that the flawed vessel had similar characteristics to the fracture specimens, thereby allowing estimates to be made of its nearness to failure during a proof test. Both the flawed and unflawed pressure vessel survived the proof pressure and 5 cycles to the working pressure, but it was apparent from the acoustic emission response during the proof cycle and the 5 cycles to the working pressure that the flawed vessel was very near failure. The flawed vessel did not survive a second cycle to the proof pressure before failure due to flaw extension through the wall (causing a leak).

Strength degradation and lifetime prediction of dental zirconia ceramics under cyclic normal loading.

PubMed

Li, Wanzhong; Xu, Yingqiang; He, Huiming; Zhao, Haidan; Sun, Jian; Hou, Yue

2015-01-01

Clinical cases show that zirconia restoration could happen fracture by accident under overloading after using a period of time. The purpose of this study is to research mechanical behavior and predict lifetime of dental zirconia ceramics under cyclic normal contact loading with experiments. Cyclic normal contact loading test and three point bending test are carried on specimens made of two brands of dental zirconia ceramic to obtain flexure strength and damage degree after different number of loading cycles. By means of damage mechanics model, damage degree under different number of contact loading cycles are calculated according to flexure strength, and verified by SEM photographs of cross section morphology of zirconia ceramics specimen phenomenologically. Relation curve of damage degree and number of cycles is fitted by polynomial fitting, then the number of loading cycles can be concluded when the specimen is complete damage. Strength degradation of two brands dental zirconia ceramics are researched in vitro, and prediction method of contact fatigue lifetime is established.

In vitro wear of Ionofil Molar AC quick glass-ionomer cement.

PubMed

Abesi, Farida; Safarcherati, Hengameh; Sadati, Javad; Kheirollahi, Hossein

2011-01-01

The aim of this study was to evaluate the three-body wear-resistance of one type of restorative glass-ionomer cement (GIC). Specimen including conventional GIC (Ionofil Molar AC Quick: IMACQ), hybrid ionomer (Fuji II LC), and composite resin (Heliomolar) were tested in a wearing machine. In this machine, a 6 kg load was applied via pressable chromium-cobalt bar at 5,000, 10,000, 20,000, 40,000, 80,000, 120,000 cycles. Specimen weight was measured by an electronical weight balance before and after each cycle. Data were analyzed using one-way analysis of variance (ANOVA) followed by a t-test, and a paired t-test at P≤0.05. The highest weight loss has been found in Fuji II LC, then in GIC IMACQ and the least wear rate has been reported in heliomolar composite in all cycles except 120,000 cycles. In 120,000 cycles, the highest weight loss was seen in GIC IMACQ, then Fuji II LC, and finally heliomolar composite. There was a statistically significant difference in weight loss between GIC IMACQ and heliomolar composite (P=0/001). The wear rate of GIC IMACQ was between those of heliomolar composite and Fuji II LC glass ionomer in all cycles except 120,000 cycles. The most important advantage of this new-generation glass ionomer is its good manipulability and also high wear-resistance compared to the hybrid ionomer. Therefore, it is suggested that it can be used as restorative material in class I restorations in primary teeth.

Reliability of Ceramic Column Grid Array Interconnect Packages Under Extreme Temperatures

NASA Technical Reports Server (NTRS)

Ramesham, Rajeshuni

2011-01-01

A paper describes advanced ceramic column grid array (CCGA) packaging interconnects technology test objects that were subjected to extreme temperature thermal cycles. CCGA interconnect electronic package printed wiring boards (PWBs) of polyimide were assembled, inspected nondestructively, and, subsequently, subjected to ex - treme-temperature thermal cycling to assess reliability for future deep-space, short- and long-term, extreme-temperature missions. The test hardware consisted of two CCGA717 packages with each package divided into four daisy-chained sections, for a total of eight daisy chains to be monitored. The package is 33 33 mm with a 27 27 array of 80%/20% Pb/Sn columns on a 1.27-mm pitch. The change in resistance of the daisy-chained CCGA interconnects was measured as a function of the increasing number of thermal cycles. Several catastrophic failures were observed after 137 extreme-temperature thermal cycles, as per electrical resistance measurements, and then the tests were continued through 1,058 thermal cycles to corroborate and understand the test results. X-ray and optical inspection have been made after thermal cycling. Optical inspections were also conducted on the CCGA vs. thermal cycles. The optical inspections were conclusive; the x-ray images were not. Process qualification and assembly is required to optimize the CCGA assembly, which is very clear from the x-rays. Six daisy chains were open out of seven daisy chains, as per experimental test data reported. The daisy chains are open during the cold cycle, and then recover during the hot cycle, though some of them also opened during the hot thermal cycle..

The Cyclic Stress-Strain Behavior of a Single Crystal Nickel-Base Superalloy. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Gabb, Timothy P.

1988-01-01

The cyclic stress-strain response and similar deformation structures of the single crystal nickel based superalloy was described under a specific set of conditions. The isothermal low cycle fatigue response and deformation structures were described at a typical intermediate temperature and at high temperature. Specimens oriented near the (001) and (111) crystallographic orientations were tested at 1050 C, where more moderate orientation effects were expected. This enabled the description of the deformation structures at each of the 2 temperatures and their relationship to the observed cyclic stress-strain behavior. The initial yield strength of all specimens tested at 650 C was controlled by the shearing of the gamma prime precipitates by dislocation pairs. Low cycle fatigue tests at 650 C had cyclic hardening, which was associated with dislocation interactions in the gamma matrix. The initial yield strength of specimens tested at 1050 C was associated with dislocation bypassing of the gamma prime precipitates. Low cycle fatigue tests at 1050 C had cyclic softening, associated with extensive dislocation recovery at the gamma-gamma prime interfaces along with some gamma prime precipitate coarsening.

In vitro wear of new indirect resin composites.

PubMed

Jain, V; Platt, J A; Moore, B K; Borges, G A

2009-01-01

This in vitro study evaluated the toothbrush abrasion wear, three-body Alabama wear and two-body pin-on-disc wear of four commercial indirect resin composites. Enamel shades of Radica (R), Sculpture Plus (S), Belleglass-NG (B) and Gradia Indirect (G) were used. For measuring wear due to toothbrush abrasion, six specimens of each group were fabricated, then brushed in a toothbrush abrasion machine for 20,000 cycles. Material loss was determined by weighing and conversion to volume loss. Three-body wear was measured on six samples for each group using an Alabama-type wear testing machine for 400,000 cycles. Wear depth was measured with a contact profilometer. For two-body wear, five disc specimens were prepared and tested in a two-body wear-testing machine against hydroxypatite sliders for 25,000 cycles. Data were analyzed with one-way analysis of variance (ANOVA) and Tukey test (alpha=0.05). Wear was the highest in Sculpture Plus by all three methods tested and the lowest wear was observed in Belleglass-NG. No statistical difference in wear was noted from Radica.

Initiation and growth of multiple-site damage in the riveted lap joint of a curved stiffened fuselage panel: An experimental and analytical study

NASA Astrophysics Data System (ADS)

Ahmed, Abubaker Ali

As part of the structural integrity research of the National Aging Aircraft Research Program, a comprehensive study on multiple-site damage (MSD) initiation and growth in a pristine lap-joint fuselage panel has been conducted. The curved stiffened fuselage panel was tested at the Full-Scale Aircraft Structural Test Evaluation and Research (FASTER) facility located at the Federal Aviation Administration William J. Hughes Technical Center. A strain survey test was conducted to verify proper load application. The panel was then subjected to a fatigue test with constant-amplitude cyclic loading. The applied loading spectrum included underload marker cycles so that crack growth history could be reconstructed from post-test fractographic examinations. Crack formation and growth were monitored via nondestructive and high-magnification visual inspections. Strain gage measurements recorded during the strain survey tests indicated that the inner surface of the skin along the upper rivet row of the lap joint experienced high tensile stresses due to local bending. During the fatigue loading, cracks were detected by eddy-current inspections at multiple rivet holes along the upper rivet row. Through-thickness cracks were detected visually after about 80% of the fatigue life. Once MSD cracks from two adjacent rivet holes linked up, there was a quick deterioration in the structural integrity of the lap joint. The linkup resulted in a 2.87" (72.9-mm) lead fatigue crack that rapidly propagated across 12 rivet holes and crossed over into the next skin bay, at which stage the fatigue test was terminated. A post-fatigue residual strength test was then conducted by loading the panel quasi-statically up to final failure. The panel failed catastrophically when the crack extended instantaneously across three additional bays. Post-test fractographic examinations of the fracture surfaces in the lap joint of the fuselage panel were conducted to characterize subsurface crack initiation and growth. Results showed evidence of fretting damage and crack initiation at multiple locations near the rivet holes along the faying surface of the skin. The subsurface cracks grew significantly along the faying surface before reaching the outer surface of the skin, forming elliptical crack fronts. A finite element model (FE) of the panel was constructed and geometrically-nonlinear analyses conducted to determine strain distribution under the applied loads. The FE model was validated by comparing the analysis results with the strain gage measurements recorded during the strain survey test. The validated FE model was then used to determine stress-intensity factors at the crack tips. Stress-intensity factor results indicated that crack growth in the lap joint was under mixed-mode; however, the opening-mode stress intensity factor was dominant. The stress-intensity factors computed from the FE analysis were used to conduct cycle-by-cycle integration of fatigue crack growth. In the cycle-by-cycle integration, the NASGRO crack growth model was used with its parameters selected to account for the effects of plasticity-induced crack closure and the test environment on crack growth rate. Fatigue crack growth predictions from cycle-by-cycle computation were in good agreement with the experimental measured crack growth data. The results of the study provide key insights into the natural development and growth of MSD cracks in the pristine lap joint. The data provided by the study represent a valuable source for the evaluation and validation of analytical methodologies used for predicting MSD crack initiation and growth.

Adaptive and Qualitative Changes in Encoding Strategy With Experience: Evidence From the Test-Expectancy Paradigm

PubMed Central

Finley, Jason R.; Benjamin, Aaron S.

2012-01-01

Three experiments demonstrated learners’ abilities to adaptively and qualitatively accommodate their encoding strategies to the demands of an upcoming test. Stimuli were word pairs. In Experiment 1, test expectancy was induced for either cued recall (of targets given cues) or free recall (of targets only) across 4 study–test cycles of the same test format, followed by a final critical cycle featuring either the expected or the unexpected test format. For final tests of both cued and free recall, participants who had expected that test format outperformed those who had not. This disordinal interaction, supported by recognition and self-report data, demonstrated not mere differences in effort based on anticipated test difficulty, but rather qualitative and appropriate differences in encoding strategies based on expected task demands. Participants also came to appropriately modulate metacognitive monitoring (Experiment 2) and study-time allocation (Experiment 3) across study–test cycles. Item and associative recognition performance, as well as self-report data, revealed shifts in encoding strategies across trials; these results were used to characterize and evaluate the different strategies that participants employed for cued versus free recall and to assess the optimality of participants’ metacognitive control of encoding strategies. Taken together, these data illustrate a sophisticated form of metacognitive control, in which learners qualitatively shift encoding strategies to match the demands of anticipated tests. PMID:22103783

HFL-10 lifting body flight control system characteristics and operational experience

NASA Technical Reports Server (NTRS)

Painter, W. D.; Sitterle, G. J.

1974-01-01

A flight evaluation was made of the mechanical hydraulic flight control system and the electrohydraulic stability augmentation system installed in the HL-10 lifting body research vehicle. Flight tests performed in the speed range from landing to a Mach number of 1.86 and the altitude range from 697 meters (2300 feet) to 27,550 meters (90,300 feet) were supplemented by ground tests to identify and correct structural resonance and limit-cycle problems. Severe limit-cycle and control sensitivity problems were encountered during the first flight. Stability augmentation system structural resonance electronic filters were modified to correct the limit-cycle problem. Several changes were made to control stick gearing to solve the control sensitivity problem. Satisfactory controllability was achieved by using a nonlinear system. A limit-cycle problem due to hydraulic fluid contamination was encountered during the first powered flight, but the problem did not recur after preflight operations were improved.

Evaluation of Ophthalmic Surgical Instrument Sterility Using Short-Cycle Sterilization for Sequential Same-Day Use.

PubMed

Chang, David F; Hurley, Nikki; Mamalis, Nick; Whitman, Jeffrey

2018-03-27

The common practice of short-cycle sterilization for ophthalmic surgical instrumentation has come under increased regulatory scrutiny. This study was undertaken to evaluate the efficacy of short-cycle sterilization processing for consecutive same-day cataract procedures. Testing of specific sterilization processing methods by an independent medical device validation testing laboratory. Phaco handpieces from 3 separate manufacturers were tested along with appropriate biologic indicators and controls using 2 common steam sterilizers. A STATIM 2000 sterilizer (SciCan, Canonsburg, PA) with the STATIM metal cassette, and an AMSCO Century V116 pre-vacuum sterilizer (STERIS, Mentor, OH) using a Case Medical SteriTite container (Case Medical, South Hackensack, NJ) rigid container were tested using phaco tips and handpieces from 3 different manufacturers. Biological indicators were inoculated with highly resistant Geobacillus stearothermophilus, and each sterility verification test was performed in triplicate. Both wrapped and contained loads were tested with full dry cycles and a 7-day storage time to simulate prolonged storage. In adherence with the manufacturers' instructions for use (IFU), short cycles (3.0-3.5-minute exposure times) for unwrapped and contained loads were also tested after only 1 minute of dry time to simulate use on a consecutive case. Additional studies were performed to demonstrate whether any moisture present in the load containing phaco handpieces postprocessing was sterile and would affect the sterility of the contents after a 3-minute transit/storage time. This approximated the upper limit of time needed to transfer a containment device to the operating room. Presence or absence of microbial growth from cultured test samples. All inoculated test samples from both sterilizers were negative for growth of the target organism whether the full dry phase was interrupted or not. Pipetted postprocessing moisture samples and swabs of the handpieces were also negative for growth after a 3-minute transit/storage time. These studies support the use of unwrapped, short-cycle sterilization that adheres to the IFU of these 2 popular Food and Drug Administration-cleared sterilizers for sequential same-day cataract surgeries. A full drying phase is not necessary when the instruments are kept within the covered sterilizer containment device for prompt use on a sequential case. Copyright © 2018 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Development of a new assessment tool for cervical myelopathy using hand-tracking sensor: Part 1: validity and reliability.

PubMed

Alagha, M Abdulhadi; Alagha, Mahmoud A; Dunstan, Eleanor; Sperwer, Olaf; Timmins, Kate A; Boszczyk, Bronek M

2017-04-01

To assess the reliability and validity of a hand motion sensor, Leap Motion Controller (LMC), in the 15-s hand grip-and-release test, as compared against human inspection of an external digital camera recording. Fifty healthy participants were asked to fully grip-and-release their dominant hand as rapidly as possible for two trials with a 10-min rest in-between, while wearing a non-metal wrist splint. Each test lasted for 15 s, and a digital camera was used to film the anterolateral side of the hand on the first test. Three assessors counted the frequency of grip-and-release (G-R) cycles independently and in a blinded fashion. The average mean of the three was compared with that measured by LMC using the Bland-Altman method. Test-retest reliability was examined by comparing the two 15-s tests. The mean number of G-R cycles recorded was: 47.8 ± 6.4 (test 1, video observer); 47.7 ± 6.5 (test 1, LMC); and 50.2 ± 6.5 (test 2, LMC). Bland-Altman indicated good agreement, with a low bias (0.15 cycles) and narrow limits of agreement. The ICC showed high inter-rater agreement and the coefficient of repeatability for the number of cycles was ±5.393, with a mean bias of 3.63. LMC appears to be valid and reliable in the 15-s grip-and-release test. This serves as a first step towards the development of an objective myelopathy assessment device and platform for the assessment of neuromotor hand function in general. Further assessment in a clinical setting and to gauge healthy benchmark values is warranted.

Thermal Cycling and High-Temperature Corrosion Tests of Rare Earth Silicate Environmental Barrier Coatings

NASA Astrophysics Data System (ADS)

Darthout, Émilien; Gitzhofer, François

2017-12-01

Lutetium and yttrium silicates, enriched with an additional secondary zirconia phase, environmental barrier coatings were synthesized by the solution precursor plasma spraying process on silicon carbide substrates. A custom-made oven was designed for thermal cycling and water vapor corrosion testing. The oven can test four specimens simultaneously and allows to evaluate environmental barrier performances under similar corrosion kinetics compared to turbine engines. Coatings structural evolution has been observed by SEM on the polished cross sections, and phase composition has been analyzed by XRD. All coatings have been thermally cycled between 1300 °C and the ambient temperature, without spallation, due to their porosity and the presence of additional secondary phase which increases the thermal cycling resistance. During water vapor exposure at 1200 °C, rare earth disilicates showed a good stability, which is contradictory with the literature, due to impurities—such as Si- and Al-hydroxides—in the water vapor jets. The presence of vertical cracks allowed the water vapor to reach the substrate and then to corrode it. It has been observed that thin vertical cracks induced some spallation after 24 h of corrosion.

Coatings for directional eutectics

NASA Technical Reports Server (NTRS)

Rairden, J. R.; Jackson, M. R.

1976-01-01

Coatings developed to provide oxidation protection for the directionally-solidified eutectic alloy NiTaC-B (4.4 weight percent Cr) were evaluated. Of seven Co-, Fe- and Ni-base coatings that were initially investigated, best resistance to cyclic oxidation was demonstrated by duplex coatings fabricated by depositing a layer of NiCrAl(Y) by vacuum evaporation from an electron beam source followed by deposition of an Al overlayer using the pack cementation process. It was found that addition of carbon to the coating alloy substantially eliminated the problem of fiber denudation in TaC-type eutectic alloys. Burner rig cycled NiTaC-B samples coated with Ni-20Cr-5Al-0.1C-0.1Y+Al and rupture-tested at 1100 deg C performed as well as or better than uncoated, vacuum cycled and air-tested NiTaC-13; however, a slight degradation with respect to uncoated material was noted in air-stress rupture tests at 870 deg C for both cycled and uncycled samples.

COMPRESSIVE FATIGUE IN TITANIUM DENTAL IMPLANTS SUBMITTED TO FLUORIDE IONS ACTION

PubMed Central

Ribeiro, Ana Lúcia Roselino; Noriega, Jorge Roberto; Dametto, Fábio Roberto; Vaz, Luís Geraldo

2007-01-01

The aim of this study was to assess the influence of a fluoridated medium on the mechanical properties of an internal hexagon implant-abutment set, by means of compression, mechanical cycling and metallographic characterization by scanning electronic microscopy. Five years of regular use of oral hygiene with a sodium fluoride solution content of 1500 ppm were simulated, immersing the samples in this medium for 184 hours, with the solutions being changed every 12 hours. Data were analyzed at a 95% confidence level with Fisher's exact test. After the action of fluoride ions, a negative influence occurred in the mechanical cycling test performed in a servohydraulic machine (Material Test System-810) set to a frequency of 15 Hz with 100,000 cycles and programmed to 60% of the maximum resistance of static compression test. The sets tended to fracture by compression on the screw, characterized by mixed ruptures with predominance of fragile fracture, as observed by microscopy. An evidence of corrosion by pitting on sample surfaces was found after the fluoride ions action. It may be concluded that prolonged contact with fluoride ions is harmful to the mechanical properties of commercially pure titanium structures. PMID:19089148

Influence of localized deformation on A-286 austenitic stainless steel stress corrosion cracking in PWR primary water

NASA Astrophysics Data System (ADS)

Fournier, L.; Savoie, M.; Delafosse, D.

2007-06-01

The low cycle fatigue (LCF) behaviour of precipitation-strengthened A-286 austenitic stainless steel was first investigated at room temperature under 0.2% plastic strain control. LCF led to hardening for the first 20 cycles and then to significant softening. LCF-induced dislocation microstructure was characterized using both bright and dark-field imaging techniques in transmission electron microscopy. Cycling softening was correlated with the formation of precipitate-free localized deformation bands. The effect of these precipitate-free localized deformation bands on A-286 stress corrosion cracking (SCC) behaviour in PWR primary water was then examined by means of constant extension rate tensile (CERT) tests at 320 °C and 360 °C. Comparative CERT tests were performed on companion specimens with similar yield stress but pre-fatigued to a few cycles (4-8) or between 125 and 200 cycles. Specimens pre-fatigued to a few cycles with no precipitate-free localized deformation bands exhibited little susceptibility to intergranular SCC (IGSCC). In contrast, the presence of precipitate-free localized deformation bands formed by pre-fatigue to between 125 and 200 cycles strongly promoted IGSCC. The interest of the approach used in this study is to provide insight into the role of localized deformation in irradiation assisted stress corrosion cracking.

Physiology and Endocrinology of the Ovarian Cycle in Macaques

PubMed Central

Weinbauer, Gerhard F.; Niehoff, Marc; Niehaus, Michael; Srivastav, Shiela; Fuchs, Antje; Van Esch, Eric; Cline, J. Mark

2009-01-01

Macaques provide excellent models for preclinical testing and safety assessment of female reproductive toxicants. Currently, cynomolgus monkeys are the predominant species for (reproductive) toxicity testing. Marmosets and rhesus monkeys are being used occasionally. The authors provide a brief review on physiology and endocrinology of the cynomolgus monkey ovarian cycle, practical guidance on assessment and monitoring of ovarian cyclicity, and new data on effects of social housing on ovarian cyclicity in toxicological studies. In macaques, cycle monitoring is achieved using daily vaginal smears for menstruation combined with cycle-timed frequent sampling for steroid and peptide hormone analysis. Owing to requirements of frequent and timed blood sampling, it is not recommended to incorporate these special evaluations into a general toxicity study design. Marmosets lack external signs of ovarian cyclicity, and cycle monitoring is done by regular determinations of progesterone. Cynomolgus and marmoset monkeys do not exhibit seasonal variations in ovarian activity, whereas such annual rhythm is pronounced in rhesus monkeys. Studies on pair- and group-housed cynomolgus monkeys revealed transient alterations in the duration and endocrinology of the ovarian cycle followed by return to normal cyclicity after approximately six months. This effect is avoided if the animals had contact with each other prior to mingling. These experiments also demonstrated that synchronization of ovarian cycles did not occur. PMID:20852722

Qualification of Fiber Optic Cables for Martian Extreme Temperature Environments

NASA Technical Reports Server (NTRS)

Ramesham, Rajeshuni; Lindensmith, Christian A.; Roberts, William T.; Rainen, Richard A.

2011-01-01

Means have been developed for enabling fiber optic cables of the Laser Induced Breakdown Spectrometer instrument to survive ground operations plus the nominal 670 Martian conditions that include Martian summer and winter seasons. The purpose of this development was to validate the use of the rover external fiber optic cabling of ChemCam for space applications under the extreme thermal environments to be encountered during the Mars Science Laboratory (MSL) mission. Flight-representative fiber optic cables were subjected to extreme temperature thermal cycling of the same diurnal depth (or delta T) as expected in flight, but for three times the expected number of in-flight thermal cycles. The survivability of fiber optic cables was tested for 600 cumulative thermal cycles from -130 to +15 C to cover the winter season, and another 1,410 cumulative cycles from -105 to +40 C to cover the summer season. This test satisfies the required 3 times the design margin that is a total of 2,010 thermal cycles (670 x 3). This development test included functional optical transmission tests during the course of the test. Transmission of the fiber optic cables was performed prior to and after 1,288 thermal cycles and 2,010 thermal cycles. No significant changes in transmission were observed on either of the two representative fiber cables subject through the 3X MSL mission life that is 2,010 thermal cycles.

Effect of LEO cycling on 125 Ah advanced design IPV nickel-hydrogen flight cells. An update

NASA Technical Reports Server (NTRS)

Smithrick, John J.; Hall, Stephen W.

1991-01-01

Validation testing of the NASA Lewis 125 Ah advanced design individual pressure vessel (IPV) nickel-hydrogen flight cells was conducted. Work consisted of characterization, storage, and cycle life testing. There was no capacity degradation after 52 days of storage with the cells in the discharged state, an open circuit, 0 C, and a hydrogen pressure of 14.5 psia. The catalyzed wall wick cells were cycled for over 11,000 cycles with no cell failures in the continuing test. One of the noncatalyzed wall wick cells failed.

Capacity fade of LiAlyNi1-x-yCoxO2 cathode for lithium-ion batteries during accelerated calendar and cycle life tests (surface analysis of LiAlyNi1-x-yCoxO2 cathode after cycle tests in restricted depth of discharge ranges)

NASA Astrophysics Data System (ADS)

Watanabe, Shoichiro; Kinoshita, Masahiro; Hosokawa, Takashi; Morigaki, Kenichi; Nakura, Kensuke

2014-07-01

Cycle performance at 60 °C for a Li Al0.10Ni0.76Co0.14O2 (NCA) cathode/graphite cell was greatly improved when a DOD range in charge-discharge cycling (ΔDOD) was restricted. The deterioration mechanism was analyzed by X-ray photoelectron spectroscopy (XPS), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and scanning transmission electron microscopy-electron energy-loss spectroscopy (STEM-EELS). Only after the cycle test in the ΔDOD of 0-100%, many micro-cracks were generated in the inter-surface between the primary particles which aggregated to form the secondary particles, and a NiO-like resistance layer with Fm3m rock salt structure was formed on each primary particle which was contact with other primary particles and electrolyte. It can be concluded that the lack of contact between the primary particles with the micro-crack generation and the formation of the new resistance layer are responsible for the capacity fading and the rise in impedance during charge-discharge cycle in the wide ΔDOD.

The Language Testing Cycle: From Inception to Washback. Series S, Number 13.

ERIC Educational Resources Information Center

Wigglesworth, Gillian, Ed.; Elder, Catherine, Ed.

A selection of essays on language testing includes: "Perspectives on the Testing Cycle: Setting the Scene" (Catherine Elder, Gillian Wigglesworth); "The Politicisation of English: The Case of the STEP Test and the Chinese Students" (Lesleyanne Hawthorne); "Developing Language Tests for Specific Populations" (Rosemary…

40 CFR 86.110-94 - Exhaust gas sampling system; diesel-cycle vehicles, and Otto-cycle vehicles requiring particulate...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Exhaust gas sampling system; diesel... Heavy-Duty Vehicles; Test Procedures § 86.110-94 Exhaust gas sampling system; diesel-cycle vehicles, and..., this is indicated by the statement “[Reserved].” (a) General. The exhaust gas sampling system described...

Buffer layer enhanced stability of sodium-ion storage

NASA Astrophysics Data System (ADS)

Wang, Xusheng; Yang, Zhanhai; Wang, Chao; Chen, Dong; Li, Rui; Zhang, Xinxiang; Chen, Jitao; Xue, Mianqi

2017-11-01

Se-Se buffer layers are introduced into tin sequences as SnSe2 single crystal to enhance the cycling stability for long-term sodium-ion storage by blazing a trail of self-defence strategy to structural pulverization especially at high current density. Specifically, under half-cell test, the SnSe2 electrodes could yield a high discharge capacity of 345 mAh g-1 after 300 cycles at 1 A g-1 and a high discharge capacity of 300 mAh g-1 after 2100 cycles at 5 A g-1 with stable coulombic efficiency and no capacity fading. Even with the ultrafast sodium-ion storage at 10 A g-1, the cycling stability still makes a positive response and a high discharge capacity of 221 mAh g-1 is demonstrated after 2700 cycles without capacity fading. The full-cell test for the SnSe2 electrodes also demonstrates the superior cycling stability. The flexible and tough Se-Se buffer layers are favourable to accommodate the sodium-ion intercalation process, and the autogenous Na2Se layers could confine the structural pulverization of further sodiated tin sequences by the slip along the Na2Se-NaxSn interfaces.

Cyclic Fiber Push-In Test Monitors Evolution of Interfacial Behavior in Ceramic Matrix Composites

NASA Technical Reports Server (NTRS)

Eldridge, Jeffrey I.

1998-01-01

SiC fiber-reinforced ceramic matrix composites are being developed for high-temperature advanced jet engine applications. Obtaining a strong, tough composite material depends critically on optimizing the mechanical coupling between the reinforcing fibers and the surrounding matrix material. This has usually been accomplished by applying a thin C or BN coating onto the surface of the reinforcing fibers. The performance of these fiber coatings, however, may degrade under cyclic loading conditions or exposure to different environments. Degradation of the coating-controlled interfacial behavior will strongly affect the useful service lifetime of the composite material. Cyclic fiber push-in testing was applied to monitor the evolution of fiber sliding behavior in both C- and BN-coated small-diameter (15-mm) SiC-fiber-reinforced ceramic matrix composites. The cyclic fiber push-in tests were performed using a desktop fiber push-out apparatus. At the beginning of each test, the fiber to be tested was aligned underneath a 10- mm-diameter diamond punch; then, the applied load was cycled between selected maximum and minimum loads. From the measured response, the fiber sliding distance and frictional sliding stresses were determined for each cycle. Tests were performed in both room air and nitrogen. Cyclic fiber push-in tests of C-coated, SiC-fiber-reinforced SiC showed progressive increases in fiber sliding distances along with decreases in frictional sliding stresses for continued cycling in room air. This rapid degradation in interfacial response was not observed for cycling in nitrogen, indicating that moisture exposure had a large effect in immediately lowering the frictional sliding stresses of C-coated fibers. These results indicate that matrix cracks bridged by C-coated fibers will not be stable, but will rapidly grow in moisture-containing environments. In contrast, cyclic fiber push-in tests of both BN-coated, SiC-fiber-reinforced SiC and BNcoated, SiC-fiber-reinforced barium strontium aluminosilicate showed no significant changes in fiber sliding behavior with continued short-term cycling in either room air or nitrogen. Although the composites with BN-coated fibers showed stable short-term cycling behavior in both environments, long-term (several-week) exposure of debonded fibers to room air resulted in dramatically increased fiber sliding distances and decreased frictional sliding stresses. These results indicate that although matrix cracks bridged by BNcoated fibers will show short-term stability, such cracks will show substantial growth with long-term exposure to moisture-containing environments. Newly formulated BN coatings, with higher moisture resistance, will be tested in the near future.

Nickel-Hydrogen Cell Testing Experience, NASA/Goddard Space Flight Center

NASA Technical Reports Server (NTRS)

Rao, Gopalakrishna M.

1999-01-01

The objectives of the project were to test the Nickel-Hydrogen Cell to: (1) verify the Aerospace Cell Flight Worthiness, (2) Elucidate the Aerospace Cell Thermal Behavior, (3) Develop the Aerospace Battery Assembly Design(s) and In-orbit Battery Management plan(s) and (4) Understand the Aerospace Cell Failure Mechanism. The tests included the LEO and GEO Life cycle tests, Calorimetric Analysis, Destructive Physical analysis, and special tests. Charts show the Mission Profile Cycling Data, Stress Cycling Data. The test data complies with the mission requirements, validating the flight worthiness of batteries. The nominal stress and mission profile cycling performance test shows the charge voltage as high as 1.60V and recharge ratio greater than 1.05. It is apparent that the electrochemical signatures alone do not provide conclusive proof for Nickel precharge. The researchers recommend a gas and positive plate analyses for further confirmation.

Influence of pH cycling on the microtensile bond strength of self-etching adhesives containing MDPB and fluoride to dentin and microhardness of enamel and dentin adjacent to restorations.

PubMed

Pedrosa, Vivianne Oliveira; Flório, Flávia Martão; Turssi, Cecília Pedroso; Amaral, Flávia Lucisano; Basting, Roberta Tarkany; França, Fabiana Mantovani

2012-12-01

To evaluate the influence of pH cycling on microtensile bond strength (µTBS) and fracture pattern of MDPB- and fluoride-containing self-etching adhesive systems to dentin, and on the cross-sectional Knoop microhardness (CSMH) of enamel and dentin adjacent to restorations. The two-step self-etching adhesive Clearfil SE Bond (SE; Kuraray), the two-step MDPBand fluoride-containing adhesive Clearfil Protect Bond (PB; Kuraray), and the one-step fluoride-containing adhesive One-Up Bond F Plus (OU; Tokuyama) were used to bond resin composite to midcoronal dentin surfaces (for µTBS testing) or to Class V cavities (for CSMH testing). µTBS and CSMH tests were performed after a 15-day period of pH cycling or storage in artificial saliva. µTBS to dentin was not affected by pH cycling or storage in artificial saliva; however, µTBS values found for PB were higher than those observed for OU. No difference existed among the µTBS values shown by PB, OU, and SE. The fracture pattern was affected by both pH cycling and adhesive system. In enamel, there was no difference in CSMH values provided by the different adhesive systems and storage media, regardless of the distance and depth from restoration. In dentin, PB and SE showed the highest CSMH values, which differed from those obtained for OU. Significantly higher CSMH values were found 100 µm from the restoration margin for all adhesive systems tested. The bond strength and microhardness in the vicinity of restorations were adhesive dependent, with MDPB and fluoride exerting no effect on the performance of the adhesive systems.

Hippocampal GABAA Receptor and Pain Sensitivity during Estrous Cycle in the Rat

PubMed Central

Taherianfard, Mahnaz; Mosavi, Mahnaz

2011-01-01

Background: Estradiol and progesterone as well as hippocampal GABAA receptors are believed to play a role in the modulation of pain. The aim of present study was to investigate the effect of intrahippocampal injections of GABAA receptor agonist (muscimol) and GABAA receptor antagonist (picrotoxin) on pain sensitivity during estrous cycle. Methods: Pain sensitivity was evaluated in rats by formalin test during all stages of estrous cycle. Animals were divided into five groups including; 1- control (intact animal); 2- sham 1 receiving 0.75 µl artificial cerebrospinal fluids (ACSF); 3- sham 2 receiving 0.75 µl alcoholic ACSF; 4- experimental 1 receiving 250 or 500 µg/rat of muscimol in 0.75 µl vehicle, and 5- experimental 2 receiving 20 or 30 µg/rat picrotoxin in 0.75 µl vehicle. Data were analyzed by Kruskal-Wallis followed by Tucky's test for pairwise comparisons using a P value of ≤0.50 for statistical significance. Results: Muscimol significantly (P<0.05) decreased pain sensitivity in all stages of estrous cycle, and the analgesic effect was higher during proestrus and estrus stages of estrous cycle than that during metestrus and diestrus stages. Picrotoxin significantly (P<0.05) increased pain sensitivity in all stages of estrous cycle, and such a hyperalgesic effect was lower during proestrus and estrus stages of estrous cycle than that during metestrus and diestrus stages. Conclusion: The findings of the present study indicate that the role of hippocampal GABAA receptor in the control of the pain sensitivity can be modulated by variation in gonadal steroids during different stages of the estrous cycle. PMID:23115414

Rapid-cycle testing cuts bed turnaround by 85%.

PubMed

2004-11-01

You can use rapid-cycle testing to try out new approaches to overcrowding much more frequently than with more traditional process improvement strategies. Improving bed turnaround notification can yield dramatic improvements. Telling staff they have to try a new process only for three days makes it easier to gain buy-in. Look for old policies that are no longer needed, yet continue to keep your staff bogged down.

Draft Test Guideline: Fish Life Cycle Toxicity

EPA Pesticide Factsheets

The following draft test guideline is part of a series of test guidelines that have been developed by EPA for use in the testing of pesticides and toxic substances, and the development of test data for submission to the Agency for review.

Hydrodynamic air lubricated compliant surface bearing for an automotive gas turbine engine. 2: Materials and coatings

NASA Technical Reports Server (NTRS)

Bhushan, B.; Ruscitto, D.; Gray, S.

1978-01-01

Material coatings for an air-lubricated, compliant journal bearing for an automotive gas turbine engine were exposed to service test temperatures of 540 C or 650 C for 300 hours, and to 10 temperature cycles from room temperatures to the service test temperatures. Selected coatings were then put on journal and partial-arc foils and tested in start-stop cycle tests at 14 kPa (2 psi) loading for 2000 cycles. Half of the test cycles were performed at a test chamber service temperature of 540 C (1000 F) or 650 C (1200 F); the other half were performed at room temperature. Based on test results, the following combinations and their service temperature limitations are recommended: HL-800 TM (CdO and graphite) on foil versus chrome carbide on journal up to 370 C (700 F); NASA PS 120 (Tribaloy 400, silver and CaF2 on journal versus uncoated foil up to 540 C (1000 F); and Kaman DES on journal and foil up to 640 C (1200 F). Kaman DES coating system was further tested successfully at 35 kPa (5 psi) loading for 2000 start-stop cycles.

T700 Blisk and Impeller Manufacturing Process Development Program.

DTIC Science & Technology

1979-11-01

700(40) Reworked Media Temperature - 790 F Average Media Pressure - 200 psi Total Cycles (Test No. 1) - 40 Total Cycles (Test No. 2) - 20 Total Time...36A(73), - 700(40" Media Temperature - 80F Average Media Pressure - 150 psi Total Cycles - 52 Total Time - 95 Minutes Some difficulty was...61)-36A(73)-700( 4O)Media Temperature - 79OF average Media Pressure - 200 psi Time - 40 cycles - 72 minutes Time - 60 cycles - 109 minutes Time - 80

Influence of number of dental autoclave treatment cycles on rotational performance of commercially available air-turbine handpieces.

PubMed

Nagai, Masahiro; Takakuda, Kazuo

2006-06-01

The influence of number of autoclave treatment cycles (N) on rotational speed and total indicated run-out of commercially available air-turbine handpieces from five manufacturers was investigated at N=0, 50, 100, 150, 200, 250 and 300 cycles, and the significance in the test results was assessed by Dunnett's multiple comparison test. Some air-turbine handpieces showed the significant differences in rotational speed at N=300 cycles, however, the decreases of the rotational speeds were only 1 to 3.5 percent. Some air-turbine handpieces showed the significant differences in total indicated run-out, however, the respective values were smaller than that at N=0 cycle. Accordingly, it can be considered that the ball bearing in the air-turbine handpieces is not affected significantly by autoclave. To further evaluate rotational performance, this study focused on the rotational vibration of the ball bearing components of the air-turbine, as measured by Fast Fourier Transform (FFT) analysis; the power spectra of frequency of the ball's revolution, frequency of the cage's rotation and frequency of the ball's rotation were comparatively investigated at N=0, 150 and 300 cycles, and the influence of autoclave was evaluated qualitatively. No abnormalities in the ball bearings were recognized.

Long Life Nickel Electrodes for a Nickel-hydrogen Cell: Cycle Life Tests

NASA Technical Reports Server (NTRS)

Lim, H. S.; Verzwyvelt, S. A.

1984-01-01

In order to develop a long life nickel electrode for a Ni/H2 cell, cycle life tests of nickel electrodes were carried out in Hi/H2 boiler plate cells. A 19 test cell matrix was made of various nickel electrode designs including three levels each of plaque mechanical strength, median pore size of the plaque, and active material loading. Test cells were cycled to the end of their life (0.5v) in a 45-minute low earth orbit cycle regime at 80% depth-of-discharge. The results show that the active material loading level affects the cycle life the most with the optimum loading at 1.6 g/cc void. Mechanical strength did not affect the cycle life noticeably in the bend strength range of 400 to 700 psi. The best plaque type appears to be one which is made of INCO nickel powder type 287 and has a median pore size of 13 micron.

Resistance Spot Welding Characteristics and High Cycle Fatigue Behavior of DP 780 Steel Sheet

NASA Astrophysics Data System (ADS)

Pal, Tapan Kumar; Bhowmick, Kaushik

2012-02-01

Resistance spot welding characteristics of DP 780 steel was investigated using peel test, microhardness test, tensile shear test, and fatigue test. Tensile shear test provides better spot weld quality than conventional peel test and hardness is not a good indicator of the susceptibility to interfacial fracture. The results of high-cycle fatigue behavior of spot welded DP 780 steel under two different parameters show that at high load low cycle range a significant difference in the S- N curve and almost similar fatigue behavior of spot welds at low load high cycle range are obtained. However, when applied load was converted to stress intensity factor, the difference in the fatigue behavior between welds diminished. Furthermore, a transition in fracture mode, i.e., interfacial and plug and hole-type at about 50% of yield load is observed.

Evaluation of rapid readout biological indicators for 132 degrees C gravity and 132 degrees C vacuum-assisted steam sterilization cycles using a new automated fluorescent reader.

PubMed

Alfa, Michelle J; Olson, Nancy; DeGagne, Pat; Jackson, Michele

2002-07-01

The primary objective of this study was to evaluate fluorescent readout results of Attest 1291 Biological Indicators (BIs) (3M Health Care, St. Paul, MN) and Attest 1296 BI test packs (containing Attest 1292 BIs) using full and fractional cycles compared with the growth data when prolonged incubation (7 days) was included. Gravity displacement and vacuum-assisted steam sterilization cycles were evaluated. A secondary objective of this study was to evaluate the new automated rapid fluorescent reader (Attest 290 Auto Reader). The rapid readout BIs for gravity displacement and vacuum-assisted steam autoclave cycles at 132 degrees C were processed using full (4 minutes) and four fractional cycles that provided 30% to 80% positive results for growth after 24 hours of incubation (48 hours of incubation for Attest 1292 BIs from the Attest 1296 test packs). Sixty of each type of BI were tested for each cycle (300 of each BI type in total). For all full steam sterilization cycles, results of the rapid fluorescent readout and the 24-hour, 48-hour, and 7-day growth tests were negative for all Attest 1291 and 1292 BIs tested. For all fractional cycles, the 24- and 48-hour growth results for the Attest 1291 and 1292 BIs, respectively, were the same as the 7-day growth results. The fractional cycle data indicated that fluorescent rapid readout was a more sensitive indicator than growth. There were rare (0.9%) false-negative results for BIs under fractional cycle conditions and these all correlated with short fractional cycle exposure times. The fluorescent rapid readout results of the 1291 BIs and 1296 BI test packs reliably predict both 24- and 48-hour and 7-day growth. These data support the value of rapid readout BIs for sterilizer monitoring for both the vacuum-assisted and the gravity displacement steam sterilization cycles. The new automated reader requires less manipulation of the BI and makes monitoring user friendly and less prone to user errors.

SURFACE DEGRADATION OF COMPOSITE RESINS BY ACIDIC MEDICINES AND pH-CYCLING

PubMed Central

Valinoti, Ana Carolina; Neves, Beatriz Gonçalves; da Silva, Eduardo Moreira; Maia, Lucianne Cople

2008-01-01

This study evaluated the effects of acidic medicines (Dimetapp® and Claritin®), under pH-cycling conditions, on the surface degradation of four composite resins (microhybrid: TPH, Concept, Opallis and Nanofilled: Supreme). Thirty disc-shaped specimens (Ø = 5.0 mm / thickness = 2.0 mm) of each composite were randomly assigned to 3 groups (n = 10): a control and two experimental groups, according to the acidic medicines evaluated. The specimens were finished and polished with aluminum oxide discs, and the surface roughness was measured by using a profilometer. After the specimens were submitted to a pH-cycling regimen and immersion in acidic medicines for 12 days, the surface roughness was measured again. Two specimens for each material and group were analyzed by scanning electron microscopy (SEM) before and after pH-cycling. Data were analyzed by the Student's-t test, ANOVA, Duncan's multiple range test and paired t-test (α=0.05). Significant increase in roughness was found only for TPH in the control group and TPH and Supreme immersed in Claritin® (p<0.05). SEM analyses showed that the 4 composite resins underwent erosion and surface degradation after being subjected to the experimental conditions. In conclusion, although the roughness was slightly affected, the pH-cycling and acidic medicines caused surface degradation of the composite resins evaluated. Titratable acidity seemed to play a more crucial role on surface degradation of composite resins than pH. PMID:19089257

Summary of Rocketdyne Engine A5 Rocket Based Combined Cycle Testing

NASA Technical Reports Server (NTRS)

Ketchum. A.; Emanuel, Mark; Cramer, John

1998-01-01

Rocketdyne Propulsion and Power (RPP) has completed a highly successful experimental test program of an advanced rocket based combined cycle (RBCC) propulsion system. The test program was conducted as part of the Advanced Reusable Technology program directed by NASA-MSFC to demonstrate technologies for low-cost access to space. Testing was conducted in the new GASL Flight Acceleration Simulation Test (FAST) facility at sea level (Mach 0), Mach 3.0 - 4.0, and vacuum flight conditions. Significant achievements obtained during the test program include 1) demonstration of engine operation in air-augmented rocket mode (AAR), ramjet mode and rocket mode and 2) smooth transition from AAR to ramjet mode operation. Testing in the fourth mode (scramjet) is scheduled for November 1998.

Study on biocompatibility, tribological property and wear debris characterization of ultra-low-wear polyethylene as artificial joint materials.

PubMed

Bian, Yan-Yan; Zhou, Lei; Zhou, Gang; Jin, Zhong-Min; Xin, Shi-Xuan; Hua, Zi-Kai; Weng, Xi-Sheng

2018-06-01

Ultra-low-wear polyethylene (ULWPE) is a new type polyethylene made by experts who are from China petrochemical research institute, which is easy to process and implant. Preliminary test showed it was more resistant to wear than that of Ultra-high-molecular weight polyethylene (UHMWPE). The purpose of the research is to study biocompatibility, bio-tribological properties and debris characterization of ULWPE. Cytotoxicity test, hemolysis test, acute/chronic toxicity and muscular implantation test were conducted according to national standard GB/T-16886/ISO-10993 for evaluation requirements of medical surgical implants. We obtained that this novel material had good biocompatibility and biological safety. The wear performance of ULWPE and UHMWPE was evaluated in a pin-on-disc (POD) wear tester within two million cycles and a knee wear simulator within six million cycles. We found that the ULWPE was higher abrasion resistance than the UHMWPE, the wear rate of ULWPE by POD test and knee wear simulator was 0.4 mg/10 6 cycles and (16.9 ± 1.8)mg/10 6 cycles respectively, while that of UHMWPE was 1.8 mg/10 6 cycles and (24.6 ± 2.4)mg/10 6 cycles. The morphology of wear debris is also an important factor to evaluate artificial joint materials, this study showed that the ULWPE wear debris gotten from the simulator had various different shapes, including spherical, block, tear, etc. The morphology of worn surface and wear debris analysis showed that wear mechanisms of ULWPE were adhesion wear, abrasive wear and fatigue wear and other wear forms, which were consistent with that of UHMWPE. Thus we conclude that ULWPE is expected to be a lifetime implantation of artificial joint. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mechanical Properties and Durability of "Waterless Concrete"

NASA Technical Reports Server (NTRS)

Toutanji, Houssam; Grugel, Richard N.

2008-01-01

Waterless concrete consists of molten elementary sulfur and aggregate. The aggregates in lunar environment will be lunar rocks and soil. Sulfur is present on the Moon in Troilite soil (FeS) and by oxidation soil iron and sulfur can be produced. Iron can be used to reinforce the sulfur concrete. Sulfur concrete specimens were cycled between liquid nitrogen (approximately 191 C) and room temperature (approximately 21 C) to simulate exposure to a lunar environment. Cycled and control specimens were subsequently tested in compression at room temperatures (approximately 21 C) and approximately 101 C. Test results showed that due to temperature cycling, compressive strength of cycled specimens was 20% of those non-cycled. Microscopic examination of the fracture surfaces from the cycled samples showed clear de-bonding of the sulfur from the aggregate material whereas it was seen well bonded in those non-cycled. This reduction in strength can be attributed to the large differences in thermal coefficients of expansion of the materials constituting the concrete which promoted cracking. Similar sulfur concrete mixtures were strengthened with short and long glass fibers. The glass fibers from lunar regolith simulant was melted in a 25 cc Pt-Rh crucible in a Sybron Thermoline high temperature MoSi2 furnace at melting temperatures of 1450 to 1600 C for times of 30 min to 1 hour. Glass fibers were cast from the melt into graphite crucibles and were annealed for a couple of hours at 600 C. Glass fibers and small rods were pulled from the melt. The glass melt wets the ceramic rod and long continuous glass fibers were easily hand drawn. The glass fibers were immediately coated with a protective polymer to maintain the mechanical strength. The glass fibers were used to reinforce sulfur concrete plated to improve the flexural strength of the sulfur concrete. Prisms beams strengthened with glass fibers were tested in 4-point bending test. Beams strengthened with glass fiber showed to exhibit an increase in the flexura strength by as much as 45%.

Orbital pacing of carbon fluxes by a ∼9-My eccentricity cycle during the Mesozoic.

PubMed

Martinez, Mathieu; Dera, Guillaume

2015-10-13

Eccentricity, obliquity, and precession are cyclic parameters of the Earth's orbit whose climatic implications have been widely demonstrated on recent and short time intervals. Amplitude modulations of these parameters on million-year time scales induce "grand orbital cycles," but the behavior and the paleoenvironmental consequences of these cycles remain debated for the Mesozoic owing to the chaotic diffusion of the solar system in the past. Here, we test for these cycles from the Jurassic to the Early Cretaceous by analyzing new stable isotope datasets reflecting fluctuations in the carbon cycle and seawater temperatures. Our results document a prominent cyclicity of ∼9 My in the carbon cycle paced by changes in the seasonal dynamics of hydrological processes and long-term sea level fluctuations. These paleoenvironmental changes are linked to a great eccentricity cycle consistent with astronomical solutions. The orbital forcing signal was mainly amplified by cumulative sequestration of organic matter in the boreal wetlands under greenhouse conditions. Finally, we show that the ∼9-My cycle faded during the Pliensbachian, which could either reflect major paleoenvironmental disturbances or a chaotic transition affecting this cycle.

Environmental qualification testing of the prototype pool boiling experiment

NASA Technical Reports Server (NTRS)

Sexton, J. Andrew

1992-01-01

The prototype Pool Boiling Experiment (PBE) flew on the STS-47 mission in September 1992. This report describes the purpose of the experiment and the environmental qualification testing program that was used to prove the integrity of the prototype hardware. Component and box level vibration and thermal cycling tests were performed to give an early level of confidence in the hardware designs. At the system level, vibration, thermal extreme soaks, and thermal vacuum cycling tests were performed to qualify the complete design for the expected shuttle environment. The system level vibration testing included three axis sine sweeps and random inputs. The system level hot and cold soak tests demonstrated the hardware's capability to operate over a wide range of temperatures and gave the project team a wider latitude in determining which shuttle thermal altitudes were compatible with the experiment. The system level thermal vacuum cycling tests demonstrated the hardware's capability to operate in a convection free environment. A unique environmental chamber was designed and fabricated by the PBE team and allowed most of the environmental testing to be performed within the project's laboratory. The completion of the test program gave the project team high confidence in the hardware's ability to function as designed during flight.

Transcription and the IELTS Speaking Test: Facilitating Development

ERIC Educational Resources Information Center

Stones, Thomas P.

2013-01-01

This article describes a transcription task cycle that was designed to facilitate the development of skills for the IELTS (International English Language Testing System) speaking test at a language school in Japan. The cycle involved practice test, transcription, student correction, teacher correction, and retrial of the original test and…

Angular Alignment Testing of Laser Mirror Mounts Under Temperature Cycling

NASA Technical Reports Server (NTRS)

Bullock, K. T.; DeYoung, R. J.; Sandford, S. P.

1997-01-01

A number of commercial and custom-built laser mirror mounts were tested for angular alignment sensitivity during temperature cycling from room temperature (20 C) to 40 C. A Nd:YAG laser beam was reflected off a mirror that was held by the mount under test and was directed to a position-sensitive detector. Horizontal and vertical movement of the reflected beam was recorded, and the angular movement, as a function of temperature (coefficient of thermal tilt (CTT)) was calculated from these data. In addition, the amount of hysteresis in the movement after cycling from room temperature to 40 C and back was determined. All commercial mounts showed greater angular movement than the simpler National Aeronautics and Space Administration Lidar Atmospheric Sensing Experiment (NASA LASE) custom mirror mounts.

Tensile and compressive constitutive response of 316 stainless steel at elevated temperatures

NASA Technical Reports Server (NTRS)

Manson, S. S.; Muralidharan, U.; Halford, G. R.

1982-01-01

It is demonstrated that creep rate of 316 SS is lower by factors of 2 to 10 in compression than in tension if the microstructure is the same and tests are conducted at identical temperatures and equal but opposite stresses. Such behavior was observed for both monotonic creep and conditions involving cyclic creep. In the latter case creep rate in both tension and compression progressively increases from cycle to cycle, rendering questionable the possibility of expressing a time-stabilized constitutive relationship. The difference in creep rates in tension and compression is considerably reduced if the tension specimen is first subjected to cycles of tensile creep (reversed by compressive plasticity), while the compression specimen is first subjected to cycles of compressive creep (reversed by tensile plasticity). In both cases, the test temperature is the same and the stresses are equal and opposite. Such reduction is a reflection of differences in microstructure of the specimens resulting from different prior mechanical history.

Cyclic stability testing of aminated-silica solid sorbent for post-combustion CO2 capture.

PubMed

Fisher, James C; Gray, McMahan

2015-02-01

The National Energy Technology Laboratory (NETL) is examining the use of solid sorbents for CO2 removal from coal-fired power plant flue gas streams. An aminated sorbent (previously reported by the NETL) is tested for stability by cyclic exposure to simulated flue gas and subsequent regeneration for 100 cycles. Each cycle was quantified using a traced gas in the simulated flue gas monitored by a mass spectrometer, which allowed for rapid determination of the capacity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Air Force Ni-H2 cell test program: State of Charge test

NASA Technical Reports Server (NTRS)

Moore, Bruce; Smellie, Douglas

1995-01-01

Nickel-Hydrogen cells are being cycled under a LEO (low earth orbit) test regime to examine the benefits of operating the cells at lower States of Charge (SOC) than typically used. A group of four cells are cycled using a voltage limiting charge regime that limits the State of Charge that the cells are allowed to reach. The test cells are then compared to identical cells being cycled at or near 100% State of Charge using a constant current charge regime.

Psychosocial Precursors and Correlates of Migraine Headache.

ERIC Educational Resources Information Center

Levor, Robert M.; And Others

1986-01-01

Tested the interactions of migraine headache cycles and sufferers' daily experiences of stressful events, emotional arousal, and physical activity. Results support a model of migraine characterized by parallel physiological and psychosocial instability during a 4-day cycle and by an interaction of personality and behavioral (self-reported stress)…

Low Temperature Life-cycle Testing of a Lithium-ion Battery for Low-earth-orbiting Spacecraft

NASA Technical Reports Server (NTRS)

Reid, Concha

2004-01-01

A flight-qualified, lithium-ion (Li-ion) battery developed for the Mars Surveyor Program 2001 lander is undergoing life-testing at low temperature under a low-Earth-orbit (LEO) profile to assess its capability to provide long term energy storage for aerospace missions. NASA has embarked upon an ambitious course to return humans to the moon by 2015-2020 in preparation for robotic and human exploration of Mars and robotic exploration of the moons of outer planets. Li-ion batteries are excellent candidates to provide power and energy storage for multiple aspects of these missions due to their low specific energy, low energy density, and excellent low temperature performance. Laboratory testing of Li-ion technology is necessary in order to assess lifetime, characterize multi-cell battery-level performance under aerospace conditions, and to gauge safety aspects of the technology. Life-cycle testing provides an opportunity to examine battery-level performance and the dynamics of individual cells in the stack over the entire life of the battery. Data generated through this testing will be critical to establish confidence in the technology for its widespread use in manned and unmanned mission. This paper discusses the performance of the 28 volt, 25 ampere-hour battery through 6000 LEO cycles, which corresponds to one year on LEO orbit. Testing is being performed at 0 C and 40% depth-of-discharge. Individual cell behaviors and their effect on the performance of the battery are described. Capacity, impedance, energy efficiency and end-of-discharge voltage at 1000 cycle intervals are reported. Results from this life-testing will help contribute to the database on battery-level performance of aerospace Li-ion batteries and low temperature cycling under LEO conditions.

Optimizing a Test Method to Evaluate Resistance of Pervious Concrete to Cycles of Freezing and Thawing in the Presence of Different Deicing Salts

PubMed Central

Tsang, Chehong; Shehata, Medhat H.; Lotfy, Abdurrahmaan

2016-01-01

The lack of a standard test method for evaluating the resistance of pervious concrete to cycles of freezing and thawing in the presence of deicing salts is the motive behind this study. Different sample size and geometry, cycle duration, and level of submersion in brine solutions were investigated to achieve an optimized test method. The optimized test method was able to produce different levels of damage when different types of deicing salts were used. The optimized duration of one cycle was found to be 24 h with twelve hours of freezing at −18 °C and twelve hours of thawing at +21 °C, with the bottom 10 mm of the sample submerged in the brine solution. Cylinder samples with a diameter of 100 mm and height of 150 mm were used and found to produce similar results to 150 mm-cubes. Based on the obtained results a mass loss of 3%–5% is proposed as a failure criterion of cylindrical samples. For the materials and within the cycles of freezing/thawing investigated here, the deicers that caused the most damage were NaCl, CaCl2 and urea, followed by MgCl2, potassium acetate, sodium acetate and calcium-magnesium acetate. More testing is needed to validate the effects of different deicers under long term exposures and different temperature ranges. PMID:28773998

Mechanical and low-cycle fatigue behavior of stainless reinforcing steel for earthquake engineering applications

NASA Astrophysics Data System (ADS)

Zhou, Yihui; Ou, Yu-Chen; Lee, George C.; O'Connor, Jerome S.

2010-09-01

Use of stainless reinforcing steel (SRS) in reinforced concrete (RC) structures is a promising solution to corrosion issues. However, for SRS to be used in seismic applications, several mechanical properties need to be investigated. These include specified and actual yield strengths, tensile strengths, uniform elongations and low-cycle fatigue behavior. Three types of SRSs (Talley S24100, Talley 316LN and Talley 2205) were tested and the results are reported in this paper. They were compared with the properties of A706 carbon reinforcing steel (RS), which is typical for seismic applications, and MMFX II, which is a high strength, corrosion resistant RS. Low-cycle fatigue tests of the RS coupons were conducted under strain control with constant amplitude to obtain strain life models of the steels. Test results show that the SRSs have slightly lower moduli of elasticity, higher uniform elongations before necking, and better low-cycle fatigue performance than A706 and MMFX II. All five types of RSs tested satisfy the requirements of the ACI 318 code on the lower limit of the tensile to yield strength ratio. Except Talley 2205, the other four types of RSs investigated meet the ACI 318 requirement that the actual yield strength does not exceed the specified yield strength by more than 18 ksi (124 MPa). Among the three types of SRSs tested, Talley S24100 possesses the highest uniform elongation before necking, and the best low-cycle fatigue performance.

Reaction of Epoxides with Wood.

DTIC Science & Technology

1984-12-01

second water cycle . The ASE values for BC are -h m--was ground to pass a 20-mesh higher than PO on the first soak cycle and do not drop f- ,tr .r_- 0rf...microns for specimens in the light and water cycle weathering due to the blocking of lignin hydroxyls so exposures. Without the action of water (leaching...separation1800 Hr. Light- Water Cycle step. The sugars would be absent in the sugar analysis and would appear to have been degraded by the test

Thermal Fatigue Behavior of Air-Plasma Sprayed Thermal Barrier Coating with Bond Coat Species in Cyclic Thermal Exposure

PubMed Central

Lu, Zhe; Myoung, Sang-Won; Jung, Yeon-Gil; Balakrishnan, Govindasamy; Lee, Jeongseung; Paik, Ungyu

2013-01-01

The effects of the bond coat species on the delamination or fracture behavior in thermal barrier coatings (TBCs) was investigated using the yclic thermal fatigue and thermal-shock tests. The interface microstructures of each TBC showed a good condition without cracking or delamination after flame thermal fatigue (FTF) for 1429 cycles. The TBC with the bond coat prepared by the air-plasma spray (APS) method showed a good condition at the interface between the top and bond coats after cyclic furnace thermal fatigue (CFTF) for 1429 cycles, whereas the TBCs with the bond coats prepared by the high-velocity oxygen fuel (HVOF) and low-pressure plasma spray (LPPS) methods showed a partial cracking (and/or delamination) and a delamination after 780 cycles, respectively. The TBCs with the bond coats prepared by the APS, HVOF and LPPS methods were fully delaminated (>50%) after 159, 36, and 46 cycles, respectively, during the thermal-shock tests. The TGO thickness in the TBCs was strongly dependent on the both exposure time and temperature difference tested. The hardness values were found to be increased only after the CFTF, and the TBC with the bond coat prepared by the APS showed the highest adhesive strength before and after the FTF. PMID:28811441

Start-stop testing of two self-acting air-lubricated spiral groove thrust bearing coatings

NASA Technical Reports Server (NTRS)

Dunfee, J. D.; Shapiro, W.

1974-01-01

Start-stop tests were conducted on air-lubricated spiral-groove thrust bearings. Application of a matrix-bonded molybdenum disulfide (MoS2) coating over a porous chrome oxide coating resulted in significantly lower friction, compared to bearings coated with chrome oxide only. The MoS2 coated bearing sustained 15,000 start-stop cycles at a maximum of 3600 rpm. Each cycle was 15 seconds on, 30 seconds off. The chrome oxide coated bearing failed by local welding after 2030 cycles. Both types of coatings exhibited early failures under higher thrust loads when operating films were insufficient to sustain the load without overheating.

Fiber post cementation strategies: effect of mechanical cycling on push-out bond strength and cement polymerization stress.

PubMed

Bergoli, Cesar Dalmolin; Amaral, Marina; Boaro, Leticia Cristina; Braga, Roberto Ruggiero; Valandro, Luiz Felipe

2012-08-01

To evaluate the effect of mechanical cycling and cementation strategies on the push-out bond strength between fiber posts and root dentin and the polymerization stresses produced using three resin cements. Eighty bovine mandibular teeth were sectioned to a length of 16 mm, prepared to 12 mm, and embedded in self-curing acrylic resin. The specimens were then distributed into 8 groups (n = 10): Gr1 - Scotchbond Multi Purpose + RelyX ARC; Gr2 - Scotchbond Multi Purpose + RelyX ARC + mechanical cycling; Gr3 - AdheSE + Multilink Automix; Gr4 - AdheSE + Multilink Automix + mechanical cycling; Gr5 - phosphoric acid + RelyX U100 (self-adhesive cement); Gr6 - phosphoric acid+ RelyX U100 + mechanical cycling; Gr7 - RelyX U100; Gr8 - RelyX U100 + mechanical cycling. The values obtained from the push-out bond strength test were submitted to two-way ANOVA and Tukey's test (p = 0.05), while the values obtained from the polymerization stress test were subjected to one-way ANOVA and Tukey's test (α = 0.05). Mechanical cycling did not affect the bond strength values (p = 0.236), while cementation strategies affected the push-out bond strength (p < 0.001). Luting with RelyX U100 and Scotch Bond Multi Purpose + RelyX ARC yielded higher push-out bond strength values. The polymerization stress results were affected by the factor "cement" (p = 0.0104): the self-adhesive cement RelyX U100 exhibited the lowest values, RelyX ARC resulted in the highest values, while Multilink Automix presented values statistically similar to the other two cements. The self-adhesive cement appears to be a good alternative for luting fiber posts due to the high push-out bond strengths and lower polymerization stress values.

Effects of High Mean Stress on High-cycle Fatigue Behavior of PWA 1480

NASA Technical Reports Server (NTRS)

Majumdar, S.; Antolovich, S. D.; Milligan, W. W.

1985-01-01

PWA 1480 is a potential candidate material for use in the high-pressure fuel turbine blade of the space shuttle main engine. As an engine material it will be subjected to high-cycle fatigue loading superimposed on a high mean stress due to combined centrifugal and thermal loadings. The present paper describes the results obtained in an ongoing program at the Argonne National Laboratory, sponsored by NASA Lewis, to determine the effects of a high mean stress on the high-cycle fatigue behavior of this material. Straight-gauge high-cycle fatigue specimens, 0.2 inch in diameter and with the specimen axis in the 001 direction, were supplied by NASA Lewis. The nominal room temperature yield and ultimate strength of the material were 146 and 154 ksi, respectively. Each specimen was polished with 1-micron diamond paste prior to testing. However, the surface of each specimen contained many pores, some of which were as large as 50 micron. In the initial tests, specimens were subjected to axial-strain-controlled cycles. However, very little cyclic plasticity was observed.

Last hired, first fired? Black-white unemployment and the business cycle.

PubMed

Couch, Kenneth A; Fairlie, Robert

2010-02-01

Studies have tested the claim that blacks are the last hired during periods of economic growth and the first fired in recessions by examining the movement of relative unemployment rates over the business cycle. Any conclusion drawn from this type of analysis must be viewed as tentative because cyclical movements in the underlying transitions into and out of unemployment are not examined. Using Current Population Survey data matched across adjacent months from 1989-2004, this article provides the first detailed examination of labor market transitions for prime-age black and white men to test the last hired, first fired hypothesis. Considerable evidence is presented that blacks are the first fired as the business cycle weakens. However no evidence is found that blacks are the last hired. Instead, blacks appear to be initially hired from the ranks of the unemployed early in the business cycle and later are drawn from nonparticipation. The narrowing of the racial unemployment gap near the peak of the business cycle is driven by a reduction in the rate of job loss for blacks rather than increases in hiring.

Last Hired, First Fired? Black-White Unemployment and the Business Cycle

PubMed Central

COUCH, KENNETH A.; FAIRLIE, ROBERT

2010-01-01

Studies have tested the claim that blacks are the last hired during periods of economic growth and the first fired in recessions by examining the movement of relative unemployment rates over the business cycle. Any conclusion drawn from this type of analysis must be viewed as tentative because cyclical movements in the underlying transitions into and out of unemployment are not examined. Using Current Population Survey data matched across adjacent months from 1989–2004, this article provides the first detailed examination of labor market transitions for prime-age black and white men to test the last hired, first fired hypothesis. Considerable evidence is presented that blacks are the first fired as the business cycle weakens. However, no evidence is found that blacks are the last hired. Instead, blacks appear to be initially hired from the ranks of the unemployed early in the business cycle and later are drawn from nonparticipation. The narrowing of the racial unemployment gap near the peak of the business cycle is driven by a reduction in the rate of job loss for blacks rather than increases in hiring. PMID:20355692

Status of Hollow Cathode Heater Development for the Space Station Plasma Contactor

NASA Technical Reports Server (NTRS)

Soulas, George C.

1994-01-01

A hollow cathode-based plasma contactor has been selected for use on the Space Station. During the operation of the plasma contactor, the hollow cathode heater will endure approximately 12000 thermal cycles. Since a hollow cathode heater failure would result in a plasma contactor failure, a hollow cathode heater development program was established to produce a reliable heater. The development program includes the heater design, process documents for both heater fabrication and assembly, and heater testing. The heater design was a modification of a sheathed ion thruster cathode heater. Heater tests included testing of the heater unit alone and plasma contactor and ion thruster testing. To date, eight heaters have been or are being processed through heater unit testing, two through plasma contactor testing and three through ion thruster testing, all using direct current power supplies. Comparisons of data from heater unit performance tests before cyclic testing, plasma contactor tests, and ion thruster tests at the ignition input current level show the average deviation of input power and tube temperature near the cathode tip to be +/-0.9 W and +/- 21 C, respectively. Heater unit testing included cyclic testing to evaluate reliability under thermal cycling. The first heater, although damaged during assembly, completed 5985 ignition cycles before failing. Four additional heaters successfully completed 6300, 6300, 700, and 700 cycles. Heater unit testing is currently ongoing for three heaters which have to date accumulated greater than 7250, greater than 5500, and greater than 5500 cycles, respectively.

Anxiolytic-like effects of restraint during the dark cycle in adolescent mice.

PubMed

Ota, Yuki; Ago, Yukio; Tanaka, Tatsunori; Hasebe, Shigeru; Toratani, Yui; Onaka, Yusuke; Hashimoto, Hitoshi; Takuma, Kazuhiro; Matsuda, Toshio

2015-05-01

Stress during developmental stage may cause psychological morbidities, and then the studies on stress are important in adolescent rodents. Restraint is used as a common stressor in rodents and the effects of restraint during the light cycle have been studied, but those of restraint during the dark cycle have not. The present study examined the effects of restraint during the light and dark cycles on anxiety behaviors in adolescent mice. Restraint for 3h during either the light or dark cycle impaired memory function in the fear conditioning test, but did not affect locomotor activity. In the elevated plus-maze test, restraint during the dark cycle reduced anxiety-like behaviors in mice. Repeated exposure to a 3-h period dark cycle restraint for 2 weeks had a similar anxiolytic-like effect. In contrast, restraint for 3h during the light cycle produced anxiety behavior in adolescent, but not adult, mice. The light cycle stress increased plasma corticosterone levels, and elevated c-Fos expression in the prefrontal cortex, paraventricular hypothalamic nucleus, basolateral amygdala and dentate gyrus, and enhanced serotonin turnover in the hippocampus and striatum, while the dark cycle stress did not. There was no difference in the stress-mediated reduction in pentobarbital-induced sleeping time between dark and light cycle restraint. These findings suggest that the anxiolytic effect of dark cycle restraint is mediated by corticosterone, serotonin or γ-aminobutyric acid-independent mechanisms, although the anxiogenic effect of light cycle restraint is associated with changes in plasma corticosterone levels and serotonin turnover in specific brain regions. Copyright © 2015 Elsevier B.V. All rights reserved.

New Screening Test Developed for the Blanching Resistance of Copper Alloys

NASA Technical Reports Server (NTRS)

Thomas-Ogbuji, Linus U.

2004-01-01

NASA's extensive efforts towards more efficient, safer, and more affordable space transportation include the development of new thrust-cell liner materials with improved capabilities and longer lives. For rocket engines fueled with liquid hydrogen, an important metric of liner performance is resistance to blanching, a phenomenon of localized wastage by cycles of oxidation-reduction due to local imbalance in the oxygen-fuel ratio. The current liner of the Space Shuttle Main Engine combustion chamber, a Cu-3Ag-0.5Zr alloy (NARloy-Z) is degraded in service by blanching. Heretofore, evaluating a liner material for blanching resistance involved elaborate and expensive hot-fire tests performed on rocket test stands. To simplify that evaluation, researchers at the NASA Glenn Research Center developed a screening test that uses simple, in situ oxidation-reduction cycling in a thermogravimetric analyzer (TGA). The principle behind this test is that resistance to oxidation or to the reduction of oxide, or both, implies resistance to blanching. Using this test as a preliminary tool to screen alloys for blanching resistance can improve reliability and save time and money. In this test a small polished coupon is hung in a TGA furnace at the desired (service) temperature. Oxidizing and reducing gases are introduced cyclically, in programmed amounts. Cycle durations are chosen by calibration, such that all copper oxides formed by oxidation are fully reduced in the next reduction interval. The sample weight is continuously acquired by the TGA as usual.

Road load simulator tests of the Gould phase 1 functional model silicon controlled rectifier ac motor controller for electric vehicles

NASA Astrophysics Data System (ADS)

Gourash, F.

1984-02-01

The test results for a functional model ac motor controller for electric vehicles and a three-phase induction motor which were dynamically tested on the Lewis Research Center road load simulator are presented. Results show that the controller has the capability to meet the SAE-J227a D cycle test schedule and to accelerate a 1576-kg (3456-lb) simulated vehicle to a cruise speed of 88.5 km/hr (55 mph). Combined motor controller efficiency is 72 percent and the power inverter efficiency alone is 89 percent for the cruise region of the D cycle. Steady state test results for motoring, regeneration, and thermal data obtained by operating the simulator as a conventional dynamometer are in agreement with the contractor's previously reported data. The regeneration test results indicate that a reduction in energy requirements for urban driving cycles is attainable with regenerative braking. Test results and data in this report serve as a data base for further development of ac motor controllers and propulsion systems for electric vehicles. The controller uses state-of-the-art silicon controlled rectifier (SCR) power semiconductors and microprocessor-based logic and control circuitry. The controller was developed by Gould Laboratories under a Lewis contract for the Department of Energy's Electric and Hybrid Vehicle program.

Road load simulator tests of the Gould phase 1 functional model silicon controlled rectifier ac motor controller for electric vehicles

NASA Technical Reports Server (NTRS)

Gourash, F.

1984-01-01

The test results for a functional model ac motor controller for electric vehicles and a three-phase induction motor which were dynamically tested on the Lewis Research Center road load simulator are presented. Results show that the controller has the capability to meet the SAE-J227a D cycle test schedule and to accelerate a 1576-kg (3456-lb) simulated vehicle to a cruise speed of 88.5 km/hr (55 mph). Combined motor controller efficiency is 72 percent and the power inverter efficiency alone is 89 percent for the cruise region of the D cycle. Steady state test results for motoring, regeneration, and thermal data obtained by operating the simulator as a conventional dynamometer are in agreement with the contractor's previously reported data. The regeneration test results indicate that a reduction in energy requirements for urban driving cycles is attainable with regenerative braking. Test results and data in this report serve as a data base for further development of ac motor controllers and propulsion systems for electric vehicles. The controller uses state-of-the-art silicon controlled rectifier (SCR) power semiconductors and microprocessor-based logic and control circuitry. The controller was developed by Gould Laboratories under a Lewis contract for the Department of Energy's Electric and Hybrid Vehicle program.

JT90 thermal barrier coated vanes

NASA Technical Reports Server (NTRS)

Sheffler, K. D.; Graziani, R. A.; Sinko, G. C.

1982-01-01

The technology of plasma sprayed thermal barrier coatings applied to turbine vane platforms in modern high temperature commercial engines was advanced to the point of demonstrated feasibility for application to commercial aircraft engines. The three thermal barrier coatings refined under this program are zirconia stabilized with twenty-one percent magnesia (21% MSZ), six percent yttria (6% YSZ), and twenty percent yttria (20% YSZ). Improvement in thermal cyclic endurance by a factor of 40 times was demonstrated in rig tests. A cooling system evolved during the program which featured air impingement cooling for the vane platforms rather than film cooling. The impingement cooling system, in combination with the thermal barrier coatings, reduced platform cooling air requirements by 44% relative to the current film cooling system. Improved durability and reduced cooling air requirements were demonstrated in rig and engine endurance tests. Two engine tests were conducted, one of 1000 cycles and the other of 1500 cycles. All three coatings applied to vanes fabricated with the final cooling system configuration completed the final 1500 cycle engine endurance test. Results of this test clearly demonstrated the durability of the 6% YSZ coating which was in very good condition after the test. The 21% MSZ and 20% YSZ coatings had numerous occurrences of significant spalling in the test.

In Vitro Evaluation of the Effect of Chemical and Thermal Stress of the Mechanical Properties of Periodontal Curettes under Simulated Conditions of Sharpening Wear.

PubMed

De Pedro, Daniel; Puglisi, Rosario; Levi, Paul; Pascual, Andrés; Nart, José

To determine whether chemical and thermal stress as well as sharpening are aspects that must be considered to determine when a curette has become too weak to be used safely without the threat of breakage. A total sample of 35 curette blades was divided into 2 principal groups, control (groups 1 to 3) and experimental (groups 4 to 6). The control group was divided into 3 colour-coded groups of 19 similar curette blades and was only subjected to progressive sharpening wear (not sterilised). The test group included 16 Gracey curette blades that were subjected to various degrees of progressive wear and different numbers of sterilisation cycles in 3 subgroups (subgroup 4 had 5 sterilisation cycles; subgroup 5 had 30 cycles and experimental subgroup 6 had 55 cycles). Using a universal testing machine, all blades were tested for strength until they fractured. No evidence was found that the simple presence or absence of sterilisation cycles produced a statistically significant difference between the two studied groups (sterilised and not sterilised). However, when comparing the six subgroups that underwent different numbers of sterilisation cycles, the analysis showed that the more sterilisation cycles a curette underwent, the more likely the curette was to fracture (p = 0.047). Sterilisation by itself does not produce a significant change in the fracture strength, whereas the number of sterilisation cycles clearly weakens the instrument. Sterilisation is a factor to control when evaluating the life of a periodontal curette for the patients' and professionals' safety.

Biomechanical comparison of stability of tibiotalocalcaneal arthrodesis with two different intramedullary retrograde nails.

PubMed

Richter, Martinus; Evers, Julia; Waehnert, Dirk; Deorio, Jim K; Pinzur, Michael; Schulze, Martin; Zech, Stefan; Ochman, Sabine

2014-03-01

The aim of the study was to compare the initial construct stability of two retrograde intramedullary nail systems for tibiotalocalcaneal arthrodesis (TTCF) (A3, Small Bone Innovations; HAN, Synthes) in a biomechanical cadaver study. Nine pairs of human cadaver bones were instrumented with two different retrograde nail systems. One tibia from each pair was randomized to either rod. The bone mineral density was determined via tomography to ensure the characteristics in each pair of tibiae were similar. All tests were performed in load-control. Displacements and forces were acquired by the sensors of the machine at a rate of 64Hz. Specimens were tested in a stepwise progression starting with six times ±125N with a frequency of 1Hz for 250cycles each step was performed (1500cycles). The maximum load was then increased to ±250N for another 14 steps or until specimen failure occurred (up to 3500cycles). Average bone mineral density was 67.4mgHA/ccm and did not differ significantly between groups (t-test, p=.28). Under cyclic loading, the range of motion (dorsiflexion/plantarflexion) at 250N was significantly lower for the HAN-group with 7.2±2.3mm compared to the A3-group with 11.8±2.9mm (t-test, p<0.01). Failure was registered for the HAN after 4571±1134cycles and after 2344±1195cycles for the A3 (t-test, p=.031). Bone mineral density significantly correlated with the number of cycles to failure in both groups (Spearman-Rho, r>.69, p<0.01). The high specimen age and low bone density simulates an osteoporotic bone situation. The HAN with only lateral distal bend but two calcaneal locking screws showed higher stability (higher number of cycles to failure and lower motion such as dorsiflexion/plantarflexion during cyclic loading) than the A3 with additional distal dorsal bend but only one calcaneal locking screw. Both constructs showed sufficient stability compared with earlier data from a similar test model. The data suggest that both implants allow for sufficient primary stability for TTCF in osteoporotic and consequently also in non-osteoporotic bone. Not applicable, experimental basic science study. Copyright © 2013 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

10 CFR Appendix C to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Dishwashers

Code of Federal Regulations, 2012 CFR

2012-01-01

... water heating to above 120 °F in at least one wash phase of the normal cycle. 2.Testing conditions: 2... dishwasher does not heat water in the normal cycle. 2.6.2Non-soil-sensing dishwashers to be tested at a... cycle. 3.4Water pressure gauge. The water pressure gauge must have a resolution of one pound per square...

A comparison of single-cycle versus multiple-cycle proof testing strategies

NASA Technical Reports Server (NTRS)

Hudak, S. J., Jr.; Mcclung, R. C.; Bartlett, M. L.; Fitzgerald, J. H.; Russell, D. A.

1990-01-01

An evaluation of single-cycle and multiple-cycle proof testing (MCPT) strategies for SSME components is described. Data for initial sizes and shapes of actual SSME hardware defects are analyzed statistically. Closed-form estimates of the J-integral for surface flaws are derived with a modified reference stress method. The results of load- and displacement-controlled stable crack growth tests on thin IN-718 plates with deep surface flaws are summarized. A J-resistance curve for the surface-cracked configuration is developed and compared with data from thick compact tension specimens. The potential for further crack growth during large unload/reload cycles is discussed, highlighting conflicting data in the literature. A simple model for ductile crack growth during MCPT based on the J-resistance curve is used to study the potential effects of key variables. The projected changes in the crack size distribution during MCPT depend on the interactions between several key parameters, including the number of proof cycles, the nature of the resistance curve, the initial crack size distribution, the component boundary conditions (load vs. displacement control), and the magnitude of the applied load or displacement. The relative advantages of single-cycle and multiple-cycle proof testing appear to be specific, therefore, to individual component geometry, material, and loading.

Monitoring of ovarian activity by measurement of urinary excretion rates of estrone glucuronide and pregnanediol glucuronide using the Ovarian Monitor, Part II: reliability of home testing.

PubMed

Blackwell, Leonard F; Vigil, Pilar; Gross, Barbara; d'Arcangues, Catherine; Cooke, Delwyn G; Brown, James B

2012-02-01

The UNDP/WHO/World Bank/Special Programme of Research, Development and Research Training in Human Reproduction (Geneva) set up a study to determine whether it is feasible for women to monitor their ovarian activity reliably by home testing. Daily self-monitoring of urinary hormone metabolites for menstrual cycle assessment was evaluated by comparison of results obtained with the Home Ovarian Monitor by untrained users both at home and in study centres. Women collected daily data for urinary estrone glucuronide (E1G) and pregnanediol glucuronide (PdG) for two cycles, then the procedure was repeated in the women's local centre (in Chile, Australia or New Zealand) giving a total of 113 duplicate cycles. The tests were performed without the benefit of replicates or quality controls. The home and centre cycles were normalized and compared to identify assay errors, and the resulting home and centre menstrual cycle profiles were averaged. Reliable mean cycle profiles were obtained with the home and centre excretion rates agreeing to within 36 ± 21 nmol/24 h for E1G and 0.77 ± 0.28 µmol/24 h for baseline PdG values (1-5 µmol/24 h). The cycles had a mean length of 28.1 ± 3.1 days (n = 112; 5th and 95th percentiles: 24 and 35 days, respectively), a mean follicular phase of 14.8 ± 3.1 days (n = 107; 5th and 95th percentiles: 11 and 21 days) and a mean luteal phase length of 13.3 ± 1.5 days (n = 106; 5th and 95th percentiles: 11 and 17 days), calculated from the day of the LH peak. The study confirmed that the Ovarian Monitor pre-coated assay tubes worked well even in the hands of lay users, without standard curves, quality controls or replicates. Point-of-care monitoring to give reliable fertility data is feasible.

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

Ma, Xiangfeng; Tanihata, Kimiaki; Miyamoto, Yoshinari

A TiC/Ni functionally gradient material (FGM) fabricated via gas-pressure combustion sintering is presently investigated to establish its mechanical and thermal properties. Attention is given to the FGM's specific thermal conductivities with different thermal cycling conditions; these are found to decrease with thermal cycling in all samples tested, implying that the lateral cracks are generated in the FGM and then propagated by the thermal cycle. High compressive stresses are induced at the TiC surface when this is constrained by a Cu block. 6 refs.

Morning-to-evening differences in oxygen uptake kinetics in short-duration cycling exercise.

PubMed

Brisswalter, Jeanick; Bieuzen, François; Giacomoni, Magali; Tricot, Véronique; Falgairette, Guy

2007-01-01

This study analyzed diurnal variations in oxygen (O(2)) uptake kinetics and efficiency during a moderate cycle ergometer exercise. Fourteen physically active diurnally active male subjects (age 23+/-5 yrs) not specifically trained at cycling first completed a test to determine their ventilatory threshold (T(vent)) and maximal oxygen consumption (VO(2max)); one week later, they completed four bouts of testing in the morning and evening in a random order, each separated by at least 24 h. For each period of the day (07:00-08:30 h and 19:00-20:30 h), subjects performed two bouts. Each bout was composed of a 5 min cycling exercise at 45 W, followed after 5 min rest by a 10 min cycling exercise at 80% of the power output associated with T(vent). Gas exchanges were analyzed breath-by-breath and fitted using a mono-exponential function. During moderate exercise, the time constant and amplitude of VO(2) kinetics were significantly higher in the morning compared to the evening. The net efficiency increased from the morning to evening (17.3+/-4 vs. 20.5+/-2%; p<0.05), and the variability of cycling cadence was greater during the morning than evening (+34%; p<0.05). These findings suggest that VO(2) responses are affected by the time of day and could be related to variability in muscle activity pattern.

A Module Experimental Process System Development Unit (MEPSDU)

NASA Technical Reports Server (NTRS)

1981-01-01

Subsequent to the design review, a series of tests was conducted on simulated modules to demonstrate that all environmental specifications (wind loading, hailstone impact, thermal cycling, and humidity cycling) are satisfied by the design. All tests, except hailstone impact, were successfully completed. The assembly sequence was simplified by virtue of eliminating the frame components and assembly steps. Performance was improved by reducing the module edge border required to accommodate the frame of the preliminary design module. An ultrasonic rolling spot bonding technique was selected for use in the machine to perform the aluminum interconnect to cell metallization electrical joints required in the MEPSDU module configuration. This selection was based on extensive experimental tests and economic analyses.

Shield evaluation and performance testing at the USMB`s Strategic Structures Testing Laboratory

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

Barczak, T.M.; Gearhart, D.F.

1996-12-31

Historically, shield performance testing is conducted by the support manufacturers at European facilities. The U.S. Bureau of Mines (USBM) has conducted extensive research in shield Mechanics and is now opening its Strategic Structures Testing (SST) Laboratory to the mining industry for shield performance testing. The SST Laboratory provides unique shield testing capabilities using the Mine Roof Simulator (MRS) load frame. The MRS provides realistic and cost-effective shield evaluation by combining both vertical and horizontal loading into a single load cycle; whereas, several load cycles would be required to obtain this loading in a static frame. In addition to these advantages,more » the USBM acts as an independent research organization to provide an unbiased assessment of shield performance. This paper describes the USBM`s shield testing program that is designed specifically to simulate in-service mining conditions using the unique the capabilities of the SST Laboratory.« less

Systematic review of the application of the plan–do–study–act method to improve quality in healthcare

PubMed Central

Taylor, Michael J; McNicholas, Chris; Nicolay, Chris; Darzi, Ara; Bell, Derek; Reed, Julie E

2014-01-01

Background Plan–do–study–act (PDSA) cycles provide a structure for iterative testing of changes to improve quality of systems. The method is widely accepted in healthcare improvement; however there is little overarching evaluation of how the method is applied. This paper proposes a theoretical framework for assessing the quality of application of PDSA cycles and explores the consistency with which the method has been applied in peer-reviewed literature against this framework. Methods NHS Evidence and Cochrane databases were searched by three independent reviewers. Empirical studies were included that reported application of the PDSA method in healthcare. Application of PDSA cycles was assessed against key features of the method, including documentation characteristics, use of iterative cycles, prediction-based testing of change, initial small-scale testing and use of data over time. Results 73 of 409 individual articles identified met the inclusion criteria. Of the 73 articles, 47 documented PDSA cycles in sufficient detail for full analysis against the whole framework. Many of these studies reported application of the PDSA method that failed to accord with primary features of the method. Less than 20% (14/73) fully documented the application of a sequence of iterative cycles. Furthermore, a lack of adherence to the notion of small-scale change is apparent and only 15% (7/47) reported the use of quantitative data at monthly or more frequent data intervals to inform progression of cycles. Discussion To progress the development of the science of improvement, a greater understanding of the use of improvement methods, including PDSA, is essential to draw reliable conclusions about their effectiveness. This would be supported by the development of systematic and rigorous standards for the application and reporting of PDSAs. PMID:24025320

Polymer Matrix Composite Lines and Ducts

NASA Technical Reports Server (NTRS)

Nettles, A. T.

2001-01-01

Since composite laminates are beginning to be identified for use in reusable launch vehicle propulsion systems, a task was undertaken to assess the feasibility of making cryogenic feedlines with integral flanges from polymer matrix composite materials. An additional level of complexity was added by having the feedlines be elbow shaped. Four materials, each with a unique manufacturing method, were chosen for this program. Feedlines were to be made by hand layup (HLU) with standard autoclave cure, HLU with electron beam cure, solvent-assisted resin transfer molding (SARTM), and thermoplastic tape laying (TTL). A test matrix of fill and drain cycles with both liquid nitrogen and liquid helium, along with a heat up to 250 F, was planned for each of the feedlines. A pressurization to failure was performed on any feedlines that passed the cryogenic cycling testing. A damage tolerance subtask was also undertaken in this study. The effects of foreign object impact to the materials used was assessed by cross-sectional examination and by permeability after impact testing. At the end of the program, the manufacture of the electron beam-cured feedlines never came to fruition. All of the TTL feedlines leaked heavily before any cryogenic testing, all of the SARTM feedlines leaked heavily after one cryogenic cycle. Thus, only the HLU with autoclave cure feedlines underwent the complete test matrix. They passed the cyclic testing and were pressurized to failure.

Strainrange partitioning life predictions of the long time metal properties council creep-fatigue tests

NASA Technical Reports Server (NTRS)

Saltsman, J. F.; Halford, G. R.

1979-01-01

The method of strainrange partitioning is used to predict the cyclic lives of the Metal Properties Council's long time creep-fatigue interspersion tests of several steel alloys. Comparisons are made with predictions based upon the time- and cycle-fraction approach. The method of strainrange partitioning is shown to give consistently more accurate predictions of cyclic life than is given by the time- and cycle-fraction approach.

Influence of creep damage on the low cycle thermal-mechanical fatigue behavior of two tantalum base alloys

NASA Technical Reports Server (NTRS)

Sheffler, K. D.; Doble, G. S.

1972-01-01

Low cycle fatigue tests have been performed on the tantalum base alloys T-111 and ASTAR 811C with synchronized, independently programmed temperature and strain cycling. The thermal-mechanical cycles applied fell into three basic categories: these were isothermal cycling, in-phase thermal cycling, and out-of-phase thermal cycling. In-phase cycling was defined as tensile deformation associated with high temperature and compressive deformation with low temperature, while out-of-phase thermal cycling was defined as the reverse case. The in-phase thermal cycling had a pronounced detrimental influence on the fatigue life of both alloys, with the life reduction being greater in the solid solution strengthened T-111 alloy than in the carbide strengthened ASTAR 811C alloy. The out-of-phase tests also showed pronounced effects on the fatigue life of both alloys, although not as dramatic.

40 CFR 86.1360 - Supplemental emission test; test cycle and procedures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Supplemental emission test; test cycle and procedures. 86.1360 Section 86.1360 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Exhaust Test Procedures for Heavy-duty...

Multi-Criteria Decision Analysis of Test Endpoints for Detecting the Effects of Endocrine Active Substances in Fish Full Life Cycle Tests

EPA Science Inventory

Fish full life cycle (FFLC) tests are increasingly required in the ecotoxicological assessment of endocrine active substances. However, FFLC tests have not been internationally standardized or validated, and it is currently unclear how such tests should best be designed to provid...

Rapid thermal cycling of new technology solar array blanket coupons

NASA Technical Reports Server (NTRS)

Scheiman, David A.; Smith, Bryan K.; Kurland, Richard M.; Mesch, Hans G.

1990-01-01

NASA Lewis Research Center is conducting thermal cycle testing of a new solar array blanket technologies. These technologies include test coupons for Space Station Freedom (SSF) and the advanced photovoltaic solar array (APSA). The objective of this testing is to demonstrate the durability or operational lifetime of the solar array interconnect design and blanket technology within a low earth orbit (LEO) or geosynchronous earth orbit (GEO) thermal cycling environment. Both the SSF and the APSA array survived all rapid thermal cycling with little or no degradation in peak performance. This testing includes an equivalent of 15 years in LEO for SSF test coupons and 30 years of GEO plus ten years of LEO for the APSA test coupon. It is concluded that both the parallel gap welding of the SSF interconnects and the soldering of the APSA interconnects are adequately designed to handle the thermal stresses of space environment temperature extremes.

Development and validation of cryogenic foam insulation for LH2 subsonic transports

NASA Technical Reports Server (NTRS)

Anthony, F. M.; Colt, J. Z.; Helenbrook, R. G.

1981-01-01

Fourteen foam insulation specimens were tested. Some were plain foam while others contained flame retardants, chopped fiberglass reinforcement and/or vapor barriers. The thermal performance of the insulation was determined by measuring the rate at which LH2 boiled from an aluminum tank insulated with the test material. The test specimens were approximately 50 mm (2 in.) thick. They were structurally scaled so that the test cycle would duplicate the maximum thermal stresses predicted for the thicker insulation of an aircraft liquid hydrogen fuel tank during a typical subsonic flight. The simulated flight cycle of approximately 10 minutes duration heated the other insulation surface to 316 K (110 F) and cooled it to 226 K (20 F) while the inner insulation surface remained at liquid hydrogen temperature of 20 K (-423 F). Two urethane foam insulations exceeded the initial life goal of 2400 simulated flight cycles and sustained 4400 cycles with only minor damage. The addition of fiberglass reinforcement of flame retardant materials to an insulation degraded thermal performance and/or the life of the foam material. Installation of vapor barriers enhanced the structural integrity of the material but did not improve thermal performance. All of the foams tested were available materials; none were developed specifically for LH2 service.

Quantifying the Adaptive Cycle | Science Inventory | US EPA

EPA Pesticide Factsheets

The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation) in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994–2011) data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and

Transient Pressure Test Article Test Program

NASA Technical Reports Server (NTRS)

Vibbart, Charles M.

1989-01-01

The Transient Pressure Test Article (TPTA) test program is being conducted at a new test facility located in the East Test Area at the National Aeronautics and Space Administration's (NASA's) Marshall Space Flight Center (MSFC) in Huntsville, Alabama. This facility, along with the special test equipment (STE) required for facility support, was constructed specifically to test and verify the sealing capability of the Redesigned Solid Rocket Motor (RSRM) field, igniter, and nozzle joints. The test article consists of full scale RSRM hardware loaded with inert propellant and assembled in a short stack configuration. The TPTA is pressurized by igniting a propellant cartridge capable of inducing a pressure rise rate which stimulates the ignition transient that occurs during launch. Dynamic loads are applied during the pressure cycle to simulate external tank attach (ETA) strut loads present on the ETA ring. Sealing ability of the redesigned joints is evaluated under joint movement conditions produced by these combined loads since joint sealing ability depends on seal resilience velocity being greater than gap opening velocity. Also, maximum flight dynamic loads are applied to the test article which is either pressurized to 600 psia using gaseous nitrogen (GN2) or applied to the test article as the pressure decays inside the test article on the down cycle after the ignition transient cycle. This new test facility is examined with respect to its capabilities. In addition, both the topic of test effectiveness versus space vehicle flight performance and new aerospace test techniques, as well as a comparison between the old SRM design and the RSRM are presented.

Analysis of lead-acid battery accelerated testing data

NASA Astrophysics Data System (ADS)

Clifford, J. E.; Thomas, R. E.

1983-06-01

Battelle conducted an independent review and analysis of the accelerated test procedures and test data obtained by Exide in the 3 year Phase 1 program to develop advanced lead acid batteries for utility load leveling. Of special importance is the extensive data obtained in deep discharge cycling tests on 60 cells at elevated temperatures over a 2-1/2 year period. The principal uncertainty in estimating cell life relates to projecting cycle life data at elevated temperature to the lower operating temperatures. The accelerated positive grid corrosion test involving continuous overcharge at 500C provided some indication of the degree of grid corrosion that might be tolerable before failure. The accelerated positive material shedding test was not examined in any detail. Recommendations are made for additional studies.

Thermal Fatigue Evaluation of Pb-Free Solder Joints: Results, Lessons Learned, and Future Trends

NASA Astrophysics Data System (ADS)

Coyle, Richard J.; Sweatman, Keith; Arfaei, Babak

2015-09-01

Thermal fatigue is a major source of failure of solder joints in surface mount electronic components and it is critically important in high reliability applications such as telecommunication, military, and aeronautics. The electronic packaging industry has seen an increase in the number of Pb-free solder alloy choices beyond the common near-eutectic Sn-Ag-Cu alloys first established as replacements for eutectic SnPb. This paper discusses the results from Pb-free solder joint reliability programs sponsored by two industry consortia. The characteristic life in accelerated thermal cycling is reported for 12 different Pb-free solder alloys and a SnPb control in 9 different accelerated thermal cycling test profiles in terms of the effects of component type, accelerated thermal cycling profile and dwell time. Microstructural analysis on assembled and failed samples was performed to investigate the effect of initial microstructure and its evolution during accelerated thermal cycling test. A significant finding from the study is that the beneficial effect of Ag on accelerated thermal cycling reliability (measured by characteristic lifetime) diminishes as the severity of the accelerated thermal cycling, defined by greater ΔT, higher peak temperature, and longer dwell time increases. The results also indicate that all the Pb-free solders are more reliable in accelerated thermal cycling than the SnPb alloy they have replaced. Suggestions are made for future work, particularly with respect to the continued evolution of alloy development for emerging application requirements and the value of using advanced analytical methods to provide a better understanding of the effect of microstructure and its evolution on accelerated thermal cycling performance.

Performance evolution of 60 kA HTS cable prototypes in the EDIPO test facility

NASA Astrophysics Data System (ADS)

Bykovsky, N.; Uglietti, D.; Sedlak, K.; Stepanov, B.; Wesche, R.; Bruzzone, P.

2016-08-01

During the first test campaign of the 60 kA HTS cable prototypes in the EDIPO test facility, the feasibility of a novel HTS fusion cable concept proposed at the EPFL Swiss Plasma Center (SPC) was successfully demonstrated. While the measured DC performance of the prototypes at magnetic fields from 8 T to 12 T and for currents from 30 kA to 70 kA was close to the expected one, an initial electromagnetic cycling test (1000 cycles) revealed progressive degradation of the performance in both the SuperPower and SuperOx conductors. Aiming to understand the reasons for the degradation, additional cycling (1000 cycles) and warm up-cool down tests were performed during the second test campaign. I c performance degradation of the SuperOx conductor reached ∼20% after about 2000 cycles, which was reason to continue with a visual inspection of the conductor and further tests at 77 K. AC tests were carried out at 0 and 2 T background fields without transport current and at 10 T/50 kA operating conditions. Results obtained in DC and AC tests of the second test campaign are presented and compared with appropriate data published recently. Concluding the first iteration of the HTS cable development program at SPC, a summary and recommendations for the next activity within the HTS fusion cable project are also reported.

Preliminary endurance tests of water vaporizers for resistojet applications

NASA Technical Reports Server (NTRS)

Morren, W. Earl; Macrae, Gregory S.

1993-01-01

Three water vaporizers designed for resistojet applications were built and tested for periods up to 500 h and 250 thermal cycles. Two of the vaporizers were not sensitive to orientation with respect to gravity, an indication of likely compatibility with low-gravity environments. Some temperatures and pressures in the third were impacted by orientation, although operation was always stable. The pressure drop across the sand-filled version increased by 147 percent in 38 h and 19 thermal cycles. Bonding of the sand granules in the downstream end of the heat exchanger was the suspected cause of failure of this vaporizer. Pressure drops across the two sintered stainless steel-filled versions were more gradual. One, with a pore size of 60 microns, showed an 80 percent increase in 500 h and 250 thermal cycles and another, with a 10 microns poresize, showed a 29 percent increase in 350 h and 175 thermal cycles. Testing of the latter metal-filled vaporizer was ongoing as of this writing. Oxidation of the porous metal packing materials in these vaporizers, with subsequent deposition of oxide particles within the pores, was believed to have caused the observed increases in pressure drops.

Life cycle replacement by gene introduction under an allee effect in periodical cicadas.

PubMed

Nariai, Yukiko; Hayashi, Saki; Morita, Satoru; Umemura, Yoshitaka; Tainaka, Kei-ichi; Sota, Teiji; Cooley, John R; Yoshimura, Jin

2011-04-06

Periodical cicadas (Magicicada spp.) in the USA are divided into three species groups (-decim, -cassini, -decula) of similar but distinct morphology and behavior. Each group contains at least one species with a 17-year life cycle and one with a 13-year cycle; each species is most closely related to one with the other cycle. One explanation for the apparent polyphyly of 13- and 17-year life cycles is that populations switch between the two cycles. Using a numerical model, we test the general feasibility of life cycle switching by the introduction of alleles for one cycle into populations of the other cycle. Our results suggest that fitness reductions at low population densities of mating individuals (the Allee effect) could play a role in life cycle switching. In our model, if the 13-year cycle is genetically dominant, a 17-year cycle population will switch to a 13-year cycle given the introduction of a few 13-year cycle alleles under a moderate Allee effect. We also show that under a weak Allee effect, different year-classes ("broods") with 17-year life cycles can be generated. Remarkably, the outcomes of our models depend only on the dominance relationships of the cycle alleles, irrespective of any fitness advantages.

Thermal cycling properties of a lead-free positive temperature coefficient thermistor in the Ba0.97(Bi0.5Na0.5)0.03TiO3 system

NASA Astrophysics Data System (ADS)

Choi, Hyoung-Seuk; Choi, Soon-Mok; Choi, Duck-Kyun

2016-01-01

A Pb-free PTC (positive temperature coefficient thermistor) heater was developed in the Ba0.97(Bi0.5Na0.5)0.03TiO3 system especially for automotive part applications. The reliability was verified by using a thermal cycling test designed on the basis of the result from a quality function deployment (QFD) analysis. We compared the thermal cycling test results from the newly-developed Pb-free PTC heaters with the results from PTC heaters currently on the market, namely, PTC heaters containing Pb. Life prediction and stress-strength relationships were analyzed together with a thermal diffusivity evaluation. We discuss the potential failure mechanisms during the thermal cycling test, focusing on the fact that electrical degradation in PTC materials is closely related to mechanical degradation due to the internal stress in the materials that comes from repeated phase changes. Different grain size distributions on the sintered bulks were considered to a key factor for explaining the different results of the reliability tests between the new Pb-free PTC heaters developed in this study and the commercial PTC heaters containing Pb.

Environmental Effects on Graphite-Epoxy Fatigue Properties

NASA Technical Reports Server (NTRS)

Sumsion, H. T.

1976-01-01

Effects of torsional and flexural fatigue on the long-time Integrity of advanced graphite-epoxy structural composites have been investigated. Torsional fatigue tests were run at stress ratios of R = 0 (zero to maximum, repeated) and R = -1 (zero mean stress) on unidirectional, angleply, and woven graphite fiber materials in air and water at room temperature and at 74 C. Flexural fatigue tests (four-point bending) with R = -1 were run in air and water at room temperature, and with R = 0 in air. Results show that, in torsional cycling, both water environment and higher test temperature contribute to significant degradation of torsional stiffness. The degradation of stiffness from torsional stress cycling was observed to be much greater with R = -1 than with simple R = 0 cycling. The effect of environment also is greater in the fully reversed cycling. Flexural fatigue results on +/- 30 deg material show a large fatigue effect, with fatigue limits of less than 50% and 30% of the static failure strength for specimens tested under stress ratios of R = 0 and R = -1, respectively. Compliance measurements indicate that the final failures are preceded by damage initiation and accumulation, which begins at about 1% of the specimen life.

The Relationship Between the Learning Style Perceptual Preferences of Urban Fourth Grade Children and the Acquisition of Selected Physical Science Concepts Through Learning Cycle Instructional Methodology.

NASA Astrophysics Data System (ADS)

Adams, Kenneth Mark

The purpose of this research was to investigate the relationship between the learning style perceptual preferences of fourth grade urban students and the attainment of selected physical science concepts for three simple machines as taught using learning cycle methodology. The sample included all fourth grade children from one urban elementary school (N = 91). The research design followed a quasi-experimental format with a single group, equivalent teacher demonstration and student investigation materials, and identical learning cycle instructional treatment. All subjects completed the Understanding Simple Machines Test (USMT) prior to instructional treatment, and at the conclusion of treatment to measure student concept attainment related to the pendulum, the lever and fulcrum, and the inclined plane. USMT pre and post-test scores, California Achievement Test (CAT-5) percentile scores, and Learning Style Inventory (LSI) standard scores for four perceptual elements for each subject were held in a double blind until completion of the USMT post-test. The hypothesis tested in this study was: Learning style perceptual preferences of fourth grade students as measured by the Dunn, Dunn, and Price Learning Style Inventory (LSI) are significant predictors of success in the acquisition of physical science concepts taught through use of the learning cycle. Analysis of pre and post USMT scores, 18.18 and 30.20 respectively, yielded a significant mean gain of +12.02. A controlled stepwise regression was employed to identify significant predictors of success on the USMT post-test from among USMT pre-test, four CAT-5 percentile scores, and four LSI perceptual standard scores. The CAT -5 Total Math and Total Reading accounted for 64.06% of the variance in the USMT post-test score. The only perceptual element to act as a significant predictor was the Kinesthetic standard score, accounting for 1.72% of the variance. The study revealed that learning cycle instruction does not appear to be sensitive to different perceptual preferences. Students with different preferences for auditory, visual, and tactile modalities, when learning, seem to benefit equally from learning cycle exposure. Increased use of a double blind for future learning styles research was recommended.

Using the Animal Model to Accelerate Response to Selection in a Self-Pollinating Crop

PubMed Central

Cowling, Wallace A.; Stefanova, Katia T.; Beeck, Cameron P.; Nelson, Matthew N.; Hargreaves, Bonnie L. W.; Sass, Olaf; Gilmour, Arthur R.; Siddique, Kadambot H. M.

2015-01-01

We used the animal model in S0 (F1) recurrent selection in a self-pollinating crop including, for the first time, phenotypic and relationship records from self progeny, in addition to cross progeny, in the pedigree. We tested the model in Pisum sativum, the autogamous annual species used by Mendel to demonstrate the particulate nature of inheritance. Resistance to ascochyta blight (Didymella pinodes complex) in segregating S0 cross progeny was assessed by best linear unbiased prediction over two cycles of selection. Genotypic concurrence across cycles was provided by pure-line ancestors. From cycle 1, 102/959 S0 plants were selected, and their S1 self progeny were intercrossed and selfed to produce 430 S0 and 575 S2 individuals that were evaluated in cycle 2. The analysis was improved by including all genetic relationships (with crossing and selfing in the pedigree), additive and nonadditive genetic covariances between cycles, fixed effects (cycles and spatial linear trends), and other random effects. Narrow-sense heritability for ascochyta blight resistance was 0.305 and 0.352 in cycles 1 and 2, respectively, calculated from variance components in the full model. The fitted correlation of predicted breeding values across cycles was 0.82. Average accuracy of predicted breeding values was 0.851 for S2 progeny of S1 parent plants and 0.805 for S0 progeny tested in cycle 2, and 0.878 for S1 parent plants for which no records were available. The forecasted response to selection was 11.2% in the next cycle with 20% S0 selection proportion. This is the first application of the animal model to cyclic selection in heterozygous populations of selfing plants. The method can be used in genomic selection, and for traits measured on S0-derived bulks such as grain yield. PMID:25943522

A nuclear method to measure spallation by thermal cycling of protective surface layers

NASA Astrophysics Data System (ADS)

Stroosnijder, M. F.; Macchi, G.

1995-05-01

After a general introduction on spallation by thermal cycling, the principle of Thin Layer Activation (TLA) is outlined. A practical setup to measure spallation of protective surface layers by thermal cycling using TLA is discussed. Its use is illustrated with the study of the spallation behaviour of an advanced thermal barrier coating. It is shown that among the various benefits, TLA has a direct relation to material loss and shows a significant increase in sensitivity over other test methods. Due to its intrinsic properties, TLA can contribute to a greater scientific understanding of material degradation by thermal cycling and it can provide a more reliable assessment of the service lives of technical components.

12 CFR 252.134 - Annual analysis conducted by the Board.

Code of Federal Regulations, 2013 CFR

2013-01-01

... RESERVE SYSTEM (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Supervisory Stress Test... analysis for each stress test cycle by no later than November 15 of each year, except with respect to...

12 CFR 252.134 - Annual analysis conducted by the Board.

Code of Federal Regulations, 2014 CFR

2014-01-01

... RESERVE SYSTEM (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Supervisory Stress Test... analysis for each stress test cycle by no later than November 15 of each year, except with respect to...

Ceramic plasma-sprayed coating of melting crucibles for casting metal fuel slugs

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

K.H. Kim; C.T. Lee; C.B. Lee

2013-10-01

Thermal cycling and melt reaction studies of ceramic coatings plasma-sprayed on Nb substrates were carried out to evaluate the performance of barrier coatings for metallic fuel casting applications. Thermal cycling tests of the ceramic plasma-sprayed coatings to 1450 degrees C showed that HfN, TiC, ZrC, and Y2O3 coating had good cycling characteristics with few interconnected cracks even after 20 cycles. Interaction studies by 1550 degrees C melt dipping tests of the plasma-sprayed coatings also indicated that HfN and Y2O3 do not form significant reaction layer between U–20 wt.% Zr melt and the coating layer. Plasma-sprayed Y2O3 coating exhibited the mostmore » promising characteristics among HfN, TiC, ZrC, and Y2O3 coating.« less

Variation of Reaction Time in Different Phases of Menstrual Cycle

PubMed Central

Kumar, Sunil; Mufti, Mehak; Kisan, Ravikiran

2013-01-01

Objective: To evaluate the influence of menstrual cycle on auditory and visual reaction times. Method: This study was conducted on thirty, healthy, regularly menstruating female subjects who were in the age group of 18-25 years. Influence of different phases of menstrual cycle on Auditory Reaction Time (ART) and Visual Reaction Time (VRT) was evaluated by using a portable audiovisual reaction time apparatus. Result: The statistical tests which were used were ANOVA and Students ‘t’ test, which showed that there were significant increases in ART and VRT during luteal phase, as compared to those in follicular phase. Conclusion: Changes in ART and VRT during different phases of menstrual cycle could be due to changes in the levels of female sex hormones, which in turn may lead to salt and water retention. PMID:24086851

The development and validation of a three-tier diagnostic test measuring pre-service elementary education and secondary science teachers' understanding of the water cycle

NASA Astrophysics Data System (ADS)

Schaffer, Dannah Lynn

The main goal of this research study was to develop and validate a three-tier diagnostic test to determine pre-service teachers' (PSTs) conceptual knowledge of the water cycle. For a three-tier diagnostic test, the first tier assesses content knowledge; in the second tier, a reason is selected for the content answer; and the third tier allows test-takers to select how confident they are in their answers for the first two tiers. The second goal of this study was to diagnose any alternative conceptions PSTs might have about the water cycle. The Water Cycle Diagnostic Test (WCDT) was developed using the theoretical framework by Treagust (1986, 1988, and 1995), and in similar studies that developed diagnostic tests (e.g., Calean & Subramaniam, 2010a; Odom & Barrow, 2007; Pesman & Eryilmaz, 2010). The final instrument consisted of 15 items along with a demographic survey that examined PSTs' weather-related experiences that may or may not have affected the PSTs' understanding of the water cycle. The WCDT was administered to 77 PSTs enrolled in science methods courses during the fall of 2012. Among the 77 participants, 37 of the PSTs were enrolled in elementary education (EPST) and 40 in secondary science (SPST). Using exploratory factor analysis, five categories were factored out for the WCDT: Phase Change of Water; Condensation and Storage; Clouds; Global Climate Change; and Movement through the Water Cycle. Analysis of the PSTs' responses demonstrated acceptable reliability (alpha = 0.62) for the instrument, and acceptable difficulty indices and discrimination indices for 12 of the items. Analysis indicated that the majority of the PSTs had a limited understanding of the water cycle. Of the PSTs sampled, SPSTs were significantly more confident in their answers' on the WCDT than the EPSTs. Completion of an undergraduate atmospheric science and/or meteorology course, as well as a higher interest in listening and/or viewing weather-related programs, resulted in PSTs having greater understanding and confidence in their answers on the WCDT. The analysis of the PSTs' responses revealed 49 potential alternative conceptions and areas where PSTs' lack of knowledge was revealed from the WCDT.

The value of usability testing for Internet-based adolescent self-management interventions: "Managing Hemophilia Online".

PubMed

Breakey, Vicky R; Warias, Ashley V; Ignas, Danial M; White, Meghan; Blanchette, Victor S; Stinson, Jennifer N

2013-10-04

As adolescents with hemophilia approach adulthood, they are expected to assume responsibility for their disease management. A bilingual (English and French) Internet-based self-management program, "Teens Taking Charge: Managing Hemophilia Online," was developed to support adolescents with hemophilia in this transition. This study explored the usability of the website and resulted in refinement of the prototype. A purposive sample (n=18; age 13-18; mean age 15.5 years) was recruited from two tertiary care centers to assess the usability of the program in English and French. Qualitative observations using a "think aloud" usability testing method and semi-structured interviews were conducted in four iterative cycles, with changes to the prototype made as necessary following each cycle. This study was approved by research ethics boards at each site. Teens responded positively to the content and appearance of the website and felt that it was easy to navigate and understand. The multimedia components (videos, animations, quizzes) were felt to enrich the experience. Changes to the presentation of content and the website user-interface were made after the first, second and third cycles of testing in English. Cycle four did not result in any further changes. Overall, teens found the website to be easy to use. Usability testing identified end-user concerns that informed improvements to the program. Usability testing is a crucial step in the development of Internet-based self-management programs to ensure information is delivered in a manner that is accessible and understood by users.

Investigation of Transmission Warming Technologies at Various Ambient Conditions

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

Jehlik, Forrest; Iliev, Simeon; Wood, Eric

This work details two approaches for evaluating transmission warming technology: experimental dynamometer testing and development of a simplified transmission efficiency model to quantify effects under varied real world ambient and driving conditions. Two vehicles were used for this investigation: a 2013 Ford Taurus and a 2011 Ford Fusion. The Taurus included a production transmission warming system and was tested over hot and cold ambient temperatures with the transmission warming system enabled and disabled. A robot driver was used to minimize driver variability and increase repeatability. Additionally the Fusion was tested cold and with the transmission pre-heated prior to completing themore » test cycles. These data were used to develop a simplified thermally responsive transmission model to estimate effects of transmission warming in real world conditions. For the Taurus, the fuel consumption variability within one standard deviation was shown to be under 0.5% for eight repeat Urban Dynamometer Driving Cycles (UDDS). These results were valid with the transmission warming system active or passive. Using the transmission warming system under 22 degrees C ambient temperature, fuel consumption reduction was shown to be 1.4%. For the Fusion, pre-warming the transmission reduced fuel consumption 2.5% for an urban drive cycle at -7 degrees C ambient temperature, with 1.5% of the 2.5% gain associated with the transmission, while consumption for the US06 test was shown to be reduced by 7% with 5.5% of the 7% gain associated with the transmission. It was found that engine warming due to conduction between the pre-heated transmission and the engine resulted in the remainder of the benefit. For +22 degrees C ambient tests, the pre-heated transmission was shown to reduce fuel consumption approximately 1% on an urban cycle, while no benefit was seen for the US06 cycle. The simplified modeling results showed gains in efficiency ranging from 0-1.5% depending on the ambient temperature and drive cycle.« less

Argonne National Laboratory Li-alloy/FeS cell testing and R and D programs

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

Gay, E.C.

1982-01-01

Groups of 12 or more identical Li-alloy/FeS cells fabricated by Eagle-Picher Industries, Inc. and Gould Inc. were operated at Argonne National Laboratory (ANL) in the status cell test program to obtain data for statistical analysis of cell cycle life and failure modes. The cells were full-size electric vehicle battery cells (150 to 350 Ah capacity) and they were cycled at the 4-h discharge rate and 8-h charge rate. The end of life was defined as a 20% loss of capacity or a decrease in the coulombic efficiency to less than 95%. Seventy-four cells (six groups of identical cells) were cycle-lifemore » tested and the results were analyzed statistically. The ultimate goal of this analysis was to predict cell and battery reliability. Testing of groups of identical cells also provided a means of identifying common failure modes which were eliminated by cell design changes. Mean time to failure (MTTF) for the cells based on the Weibull distribution is presented.« less

78 FR 59791 - Annual Company-Run Stress Tests at Banking Organizations With Total Consolidated Assets of More...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-30

... Stress Tests at Banking Organizations With Total Consolidated Assets of More Than $10 Billion But Less... Stress Test Cycle AGENCY: Board of Governors of the Federal Reserve System (Board). ACTION: Interim final... framework) in their stress tests for the stress test cycle that begins October 1, 2013. For this stress test...

Inventory and review of aquifer storage and recovery in southern Florida

USGS Publications Warehouse

Reese, Ronald S.

2002-01-01

publications > water resources investigations > report 02-4036 US Department of the Interior US Geological Survey WRI 02-4036Inventory and Review of Aquifer Storage and Recovery in Southern Florida By Ronald S. ReeseTallahassee, Florida 2002 prepared as part of the U.S. Geological Survey Place-Based Studies Program ABSTRACT Abstract Introduction Inventory of Data Case Studies Summary References Tables Aquifer storage and recovery in southern Florida has been proposed on an unprecedented scale as part of the Comprehensive Everglades Restoration Plan. Aquifer storage and recovery wells were constructed or are under construction at 27 sites in southern Florida, mostly by local municipalities or counties located in coastal areas. The Upper Floridan aquifer, the principal storage zone of interest to the restoration plan, is the aquifer being used at 22 of the sites. The aquifer is brackish to saline in southern Florida, which can greatly affect the recovery of the freshwater recharged and stored.Well data were inventoried and compiled for all wells at most of the 27 sites. Construction and testing data were compiled into four main categories: (1) well identification, location, and construction data; (2) hydraulic test data; (3) ambient formation water-quality data; and (4) cycle testing data. Each cycle during testing or operation includes periods of recharge of freshwater, storage, and recovery that each last days or months. Cycle testing data include calculations of recovery efficiency, which is the percentage of the total amount of potable water recharged for each cycle that is recovered.Calculated cycle test data include potable water recovery efficiencies for 16 of the 27 sites. However, the number of cycles at most sites was limited; except for two sites, the highest number of cycles was five. Only nine sites had a recovery efficiency above 10 percent for the first cycle, and 10 sites achieved a recovery efficiency above 30 percent during at least one cycle. The highest recovery efficiency achieved per cycle was 84 percent for cycle 16 at the Boynton Beach site.Factors that could affect recovery of freshwater varied widely between sites. The thickness of the open storage zone at all sites ranged from 45 to 452 feet. For sites with the storage zone in the Upper Floridan aquifer, transmissivity based on tests of the storage zones ranged from 800 to 108,000 feet squared per day, leakance values indicated that confinement is not good in some areas, and the chloride concentration of ambient water ranged from 500 to 11,000 milligrams per liter.Based on review of four case studies and data from other sites, several hydrogeologic and design factors appear to be important to the performance of aquifer storage and recovery in the Floridan aquifer system. Performance is maximized when the storage zone is thin and located at the top of the Upper Floridan aquifer, and transmissivity and salinity of the storage zone are moderate (less than 30,000 feet squared per day and 3,000 milligrams per liter of chloride concentration, respectively). The structural setting at a site could also be important because of the potential for updip migration of a recharged freshwater bubble due to density contrast or loss of overlying confinement due to deformation.

Adenosine triphosphate bioluminescence for bacteriologic surveillance and reprocessing strategies for minimizing risk of infection transmission by duodenoscopes.

PubMed

Sethi, Saurabh; Huang, Robert J; Barakat, Monique T; Banaei, Niaz; Friedland, Shai; Banerjee, Subhas

2017-06-01

Recent outbreaks of duodenoscope-transmitted infections underscore the importance of adequate endoscope reprocessing. Adenosine triphosphate (ATP) bioluminescence testing allows rapid evaluation of endoscopes for bacteriologic/biologic residue. In this prospective study we evaluate the utility of ATP in bacteriologic surveillance and the effects of endoscopy staff education and dual cycles of cleaning and high-level disinfection (HLD) on endoscope reprocessing. ATP bioluminescence was measured after precleaning, manual cleaning, and HLD on rinsates from suction-biopsy channels of all endoscopes and elevator channels of duodenoscopes/linear echoendoscopes after use. ATP bioluminescence was remeasured in duodenoscopes (1) after re-education and competency testing of endoscopy staff and subsequently (2) after 2 cycles of precleaning and manual cleaning and single cycle of HLD or (3) after 2 cycles of precleaning, manual cleaning, and HLD. The ideal ATP bioluminescence benchmark of <200 relative light units (RLUs) after manual cleaning was achieved from suction-biopsy channel rinsates of all endoscopes, but 9 of 10 duodenoscope elevator channel rinsates failed to meet this benchmark. Re-education reduced RLUs in duodenoscope elevator channel rinsates after precleaning (23,218.0 vs 1340.5 RLUs, P < .01) and HLD (177.0 vs 12.0 RLUs, P < .01). After 2 cycles of manual cleaning/HLD, duodenoscope elevator channel RLUs achieved levels similar to sterile water, with corresponding negative cultures. ATP testing offers a rapid, inexpensive alternative for detection of endoscope microbial residue. Re-education of endoscopy staff and 2 cycles of cleaning and HLD decreased elevator channel RLUs to levels similar to sterile water and may therefore minimize the risk of transmission of infections by duodenoscopes. Copyright © 2017 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

Fatigue and failure responses of lead zirconate titanate multilayer actuator under unipolar high-field electric cycling

NASA Astrophysics Data System (ADS)

Zeng, Fan Wen; Wang, Hong; Lin, Hua-Tay

2013-07-01

Lead zirconate titanate (PZT) multilayer actuators with an interdigital electrode design were studied under high electric fields (3 and 6 kV/mm) in a unipolar cycling mode. A 100 Hz sine wave was used in cycling. Five specimens tested under 6 kV/mm failed from 3.8 × 105 to 7 × 105 cycles, whereas three other specimens tested under 3 kV/mm were found to be still functional after 108 cycles. Variations in piezoelectric and dielectric responses of the tested specimens were observed during the fatigue test, depending on the measuring and cycling conditions. Selected fatigued and damaged actuators were characterized using an impedance analyzer or small signal measurement. Furthermore, involved fatigue and failure mechanisms were investigated using scanning acoustic microscope and scanning electron microscope. The extensive cracks and porous regions were revealed across the PZT layers on the cross sections of a failed actuator. The results from this study have demonstrated that the high-field cycling can accelerate the fatigue of PZT stacks as long as the partial discharge is controlled. The small signal measurement can also be integrated into the large signal measurement to characterize the fatigue response of PZT stacks in a more comprehensive basis. The former can further serve as an experimental method to test and monitor the behavior of PZT stacks.

40 CFR 86.1439 - Certification Short Test emission test procedures-EPA.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) Emission Regulations for New Gasoline-Fueled Otto-Cycle Light-Duty Vehicles and New Gasoline-Fueled Otto-Cycle Light-Duty Trucks; Certification Short Test Procedures § 86.1439 Certification Short... seconds (mt=30), whichever comes second. (B) The vehicle fails the idle mode and the test is immediately...

40 CFR 86.1439 - Certification Short Test emission test procedures-EPA.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) Emission Regulations for New Gasoline-Fueled Otto-Cycle Light-Duty Vehicles and New Gasoline-Fueled Otto-Cycle Light-Duty Trucks; Certification Short Test Procedures § 86.1439 Certification Short... seconds (mt=30), whichever comes second. (B) The vehicle fails the idle mode and the test is immediately...

40 CFR 91.410 - Engine test cycle.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Engine test cycle. 91.410 Section 91...) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test Procedures § 91.410 Engine... in dynamometer operation tests of marine engines. (b) During each non-idle mode the specified speed...

Research on Correlation between Vehicle Cycle and Engine Cycle in Heavy-duty commercial vehicle

NASA Astrophysics Data System (ADS)

lin, Chen; Zhong, Wang; Shuai, Liu

2017-12-01

In order to study the correlation between vehicle cycle and engine cycle in heavy commercial vehicles, the conversion model of vehicle cycle to engine cycle is constructed based on the vehicle power system theory and shift strategy, which considers the verification on diesel truck. The results show that the model has high rationality and reliability in engine operation. In the acceleration process of high speed, the difference of model gear selection leads to the actual deviation. Compared with the drum test, the engine speed distribution obtained by the model deviates to right, which fits to the lower grade. The grade selection has high influence on the model.

Prediction/discussion-based learning cycle versus conceptual change text: comparative effects on students' understanding of genetics

NASA Astrophysics Data System (ADS)

khawaldeh, Salem A. Al

2013-07-01

Background and purpose: The purpose of this study was to investigate the comparative effects of a prediction/discussion-based learning cycle (HPD-LC), conceptual change text (CCT) and traditional instruction on 10th grade students' understanding of genetics concepts. Sample: Participants were 112 10th basic grade male students in three classes of the same school located in an urban area. The three classes taught by the same biology teacher were randomly assigned as a prediction/discussion-based learning cycle class (n = 39), conceptual change text class (n = 37) and traditional class (n = 36). Design and method: A quasi-experimental research design of pre-test-post-test non-equivalent control group was adopted. Participants completed the Genetics Concept Test as pre-test-post-test, to examine the effects of instructional strategies on their genetics understanding. Pre-test scores and Test of Logical Thinking scores were used as covariates. Results: The analysis of covariance showed a statistically significant difference between the experimental and control groups in the favor of experimental groups after treatment. However, no statistically significant difference between the experimental groups (HPD-LC versus CCT instruction) was found. Conclusions: Overall, the findings of this study support the use of the prediction/discussion-based learning cycle and conceptual change text in both research and teaching. The findings may be useful for improving classroom practices in teaching science concepts and for the development of suitable materials promoting students' understanding of science.

Effect of operational cycle time length on nitrogen removal in an alternating oxidation ditch system.

PubMed

Mantziaras, I D; Stamou, A; Katsiri, A

2011-06-01

This paper refers to nitrogen removal optimization of an alternating oxidation ditch system through the use of a mathematical model and pilot testing. The pilot system where measurements have been made has a total volume of 120 m(3) and consists of two ditches operating in four phases during one cycle and performs carbon oxidation, nitrification, denitrification and settling. The mathematical model consists of one-dimensional mass balance (convection-dispersion) equations based on the IAWPRC ASM 1 model. After the calibration and verification of the model, simulation system performance was made. Optimization is achieved by testing operational cycles and phases with different time lengths. The limits of EU directive 91/271 for nitrogen removal have been used for comparison. The findings show that operational cycles with smaller time lengths can achieve higher nitrogen removals and that an "equilibrium" between phase time percentages in the whole cycle, for a given inflow, must be achieved.

Reliability of CGA/LGA/HDI Package Board/Assembly (Revision A)

NASA Technical Reports Server (NTRS)

Ghaffarian, Reza

2013-01-01

This follow-up report presents reliability test results conducted by thermal cycling of five CGA assemblies evaluated under two extreme cycle profiles, representative of use for high-reliability applications. The thermal cycles ranged from a low temperature of 55 C to maximum temperatures of either 100 C or 125 C with slow ramp-up rate (3 C/min) and dwell times of about 15 minutes at the two extremes. Optical photomicrographs that illustrate key inspection findings of up to 200 thermal cycles are presented. Other information presented include an evaluation of the integrity of capacitors on CGA substrate after thermal cycling as well as process evaluation for direct assembly of an LGA onto PCB. The qualification guidelines, which are based on the test results for CGA/LGA/HDI packages and board assemblies, will facilitate NASA projects' use of very dense and newly available FPGA area array packages with known reliably and mitigation risks, allowing greater processing power in a smaller board footprint and lower system weight.

Inertial aided cycle slip detection and identification for integrated PPP GPS and INS.

PubMed

Du, Shuang; Gao, Yang

2012-10-25

The recently developed integrated Precise Point Positioning (PPP) GPS/INS system can be useful to many applications, such as UAV navigation systems, land vehicle/machine automation and mobile mapping systems. Since carrier phase measurements are the primary observables in PPP GPS, cycle slips, which often occur due to high dynamics, signal obstructions and low satellite elevation, must be detected and repaired in order to ensure the navigation performance. In this research, a new algorithm of cycle slip detection and identification has been developed. With the aiding from INS, the proposed method jointly uses WL and EWL phase combinations to uniquely determine cycle slips in the L1 and L2 frequencies. To verify the efficiency of the algorithm, both tactical-grade and consumer-grade IMUs are tested by using a real dataset collected from two field tests. The results indicate that the proposed algorithm can efficiently detect and identify the cycle slips and subsequently improve the navigation performance of the integrated system.

NICMOS Cycles 13 and 14 Calibration Plans

NASA Astrophysics Data System (ADS)

Arribas, Santiago; Bergeron, Eddie; de Jong, Roeof; Malhotra, Sangeeta; Mobasher, Bahram; Noll, Keith; Schultz, Al; Wiklind, Tommy; Xu, Chun

2005-11-01

This document summarizes the NICMOS Calibration Plans for Cycles 13 and 14. These plans complement the SMOV3b, the Cycle 10 (interim), and the Cycles 11 and 12 (regular) calibration programs executed after the installation of the NICMOS Cooling System (NCS).. These previous programs have shown that the instrument is very stable, which has motivated a further reduction in the frequency of the monitoring programs for Cycle 13. In addition, for Cycle 14 some of these programs were slightly modified to account for 2 Gyro HST operations. The special calibrations on Cycle 13 were focussed on a follow up of the spectroscopic recalibration initiated in Cycle 12. This program led to the discovery of a possible count rate non-linearity, which has triggered a special program for Cycle 13 and a number of subsequent tests and calibrations during Cycle 14. At the time of writing this is a very active area of research. We also briefly comment on other calibrations defined to address other specific issues like: the autoreset test, the SPAR sequences tests, and the low-frequency flat residual for NIC1. The calibration programs for the 2-Gyro campaigns are not included here, since they have been described somewhere else. Further details and updates on specific programs can be found via the NICMOS web site.

Cycle life test of secondary spacecraft cells

NASA Technical Reports Server (NTRS)

Harkness, J. D.

1980-01-01

The results of the life cycling program on rechargeable calls are reported. Information on required data, the use of which the data will be put, application details, including orbital description, charge control methods, load rquirements, etc., are given. Cycle tests were performed on 660 sealed, nickel cadmium cells. The cells consisted of seven sample classifications ranging form 3.0 to 20 amp. hours. Nickel cadmium, silver cadmium, and silver zinc sealed cells, excluding synchronous orbit and accelerated test packs were added. The capacities of the nickel cadmium cells, the silver cadmium and the silver zinc cells differed in range of amp hrs. The cells were cylced under different load, charge control, and temperature conditions. All cell packs are recharged by use of a pack voltage limit. All charging is constant current until the voltage limit is reached.

Effect of Red Bull energy drink on repeated Wingate cycle performance and bench-press muscle endurance.

PubMed

Forbes, Scott C; Candow, Darren G; Little, Jonathan P; Magnus, Charlene; Chilibeck, Philip D

2007-10-01

The purpose of this study was to determine the effects of Red Bull energy drink on Wingate cycle performance and muscle endurance. Healthy young adults (N = 15, 11 men, 4 women, 21 +/- 5 y old) participated in a crossover study in which they were randomized to supplement with Red Bull (2 mg/kg body mass of caffeine) or isoenergetic, isovolumetric, noncaffeinated placebo, separated by 7 d. Muscle endurance (bench press) was assessed by the maximum number of repetitions over 3 sets (separated by 1-min rest intervals) at an intensity corresponding to 70% of baseline 1-repetition maximum. Three 30-s Wingate cycling tests (load = 0.075 kp/kg body mass), with 2 min recovery between tests, were used to assess peak and average power output. Red Bull energy drink significantly increased total bench-press repetitions over 3 sets (Red Bull = 34 +/- 9 vs. placebo = 32 +/- 8, P %%%lt; 0.05) but had no effect on Wingate peak or average power (Red Bull = 701 +/- 124 W vs. placebo = 700 +/- 132 W, Red Bull = 479 +/- 74 W vs. placebo = 471 +/- 74 W, respectively). Red Bull energy drink significantly increased upper body muscle endurance but had no effect on anaerobic peak or average power during repeated Wingate cycling tests in young healthy adults.

(Invited) Effect of Aging on Mechanical Properties of Lithium Ion Cell Components

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

Wu, Zenan; Cao, Lei; Hartig, Julia

The mechanical properties of aged and fresh lithium ion cell components are evaluated in this paper. Cells components were obtained from destructive physical analysis of 40Ah NMC/Graphite-based pouch cells before and after cycling and were subjected to mechanical testing. The aging tests comprised of cycling the cell across a voltage window of 4.1V to 3.0V at room temperature (25?). Using a 2C charging rate and 1C discharging rate, the cells were subjected to over 5600 cycles before a 80% drop in the name-plate capacity was observed. Mechanical tests, including compression test, tensile test and indentation test, were conducted on themore » cell components to investigate differences in the mechanical performance. Comparison of the fresh and aged cells components shows that cycling the cells has different degrees of impact on the different cell components. Anodes suffered the most serious deterioration in mechanical properties while separators remained intact under the test condition investigated.« less

Fatigue, Creep-Fatigue, and Thermomechanical Fatigue Life Testing of Alloys

NASA Technical Reports Server (NTRS)

Halford, Gary R.; Lerch, Bradley A.; McGaw, Michael A.

2000-01-01

The fatigue crack initiation resistance of an alloy is determined by conducting a series of tests over a range of values of stress amplitude or strain range. The observed number of cycles to failure is plotted against the stress amplitude or strain range to obtain a fatigue curve. The fatigue properties quoted for an alloy are typically the constants used in the equation(s) that describe the fatigue curve. Fatigue lives of interest may be as low as 10(exp 2) or higher than 10(exp 9) cycles. Because of the enormous scatter associated with fatigue, dozens of tests may be needed to confidently establish a fatigue curve, and the cost may run into several thousands of dollars. To further establish the effects on fatigue life of the test temperature, environment, alloy condition, mean stress effects, creep-fatigue effects, thermomechanical cycling, etc. requires an extraordinarily large and usually very costly test matrix. The total effort required to establish the fatigue resistance of an alloy should not be taken lightly. Fatigue crack initiation tests are conducted on relatively small and presumed to be initially crack-free, samples of an alloy that are intended to be representative of the alloy's metallurgical and physical condition. Generally, samples are smooth and have uniformly polished surfaces within the test section. Some may have intentionally machined notches of well-controlled geometry, but the surface at the root of the notch is usually not polished. The purpose of polishing is to attain a reproducible surface finish. This is to eliminate surface finish as an uncontrolled variable. Representative test specimen geometries will be discussed later. Test specimens are cyclically loaded until macroscopically observable cracks initiate and eventually grow to failure. Normally, the fatigue failure life of a specimen is defined as the number of cycles to separation of the specimen into two pieces. Alternative definitions are becoming more common, particularly for low-cycle fatigue testing, wherein some prescribed indication of impending failure due to cracking is adopted. Specific criteria will be described later. As a rule, cracks that develop during testing are not measured nor are the test parameters intentionally altered owing to the presence of cracking.

Development of Electric Power Units Driven by Waste Heat

NASA Astrophysics Data System (ADS)

Inoue, Naoyuki; Takeuchi, Takao; Kaneko, Atsushi; Uchimura, Tomoyuki; Irie, Kiichi; Watanabe, Hiroyoshi

For the development of a simple and compact power generator driven by waste heat, working fluids and an expander were studied, then a practical electric power unit was put to test. Many working fluids were calculated with the low temperature power cycle (evaporated at 77°C, condensed at 42°C),and TFE,R123,R245fa were selected to be suitable for the cycle. TFE(Trifluoroethanol CF3CH2OH) was adopted to the actual power generator which was tested. A radial turbine was adopted as an expander, and was newly designed and manufactured for working fluid TFE. The equipment was driven by hot water as heat source and cooling water as cooling source, and generated power was connected with electric utility. Characteristics of the power generating cycle and characteristics of the turbine were obtained experimentally.

40 CFR 86.1335-90 - Cool-down procedure.

Code of Federal Regulations, 2012 CFR

2012-07-01

... cold cycle exhaust emission test may begin after a cool-down only when the engine oil and water... Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1335-90 Cool-down procedure. (a) This cool-down procedure applies to Otto-cycle and diesel engines...

40 CFR 86.1335-90 - Cool-down procedure.

Code of Federal Regulations, 2011 CFR

2011-07-01

... cold cycle exhaust emission test may begin after a cool-down only when the engine oil and water... Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1335-90 Cool-down procedure. (a) This cool-down procedure applies to Otto-cycle and diesel engines...

40 CFR 86.1335-90 - Cool-down procedure.

Code of Federal Regulations, 2013 CFR

2013-07-01

... cold cycle exhaust emission test may begin after a cool-down only when the engine oil and water... Regulations for New Otto-Cycle and Diesel Heavy-Duty Engines; Gaseous and Particulate Exhaust Test Procedures § 86.1335-90 Cool-down procedure. (a) This cool-down procedure applies to Otto-cycle and diesel engines...

Fatigue-test acceleration with flight-by-flight loading and heating to simulate supersonic-transport operation

NASA Technical Reports Server (NTRS)

Imig, L. A.; Garrett, L. E.

1973-01-01

Possibilities for reducing fatigue-test time for supersonic-transport materials and structures were studied in tests with simulated flight-by-flight loading. In order to determine whether short-time tests were feasible, the results of accelerated tests (2 sec per flight) were compared with the results of real-time tests (96 min per flight). The effects of design mean stress, the stress range for ground-air-ground cycles, simulated thermal stress, the number of stress cycles in each flight, and salt corrosion were studied. The flight-by-flight stress sequences were applied to notched sheet specimens of Ti-8Al-1Mo-1V and Ti-6Al-4V titanium alloys. A linear cumulative-damage analysis accounted for large changes in stress range of the simulated flights but did not account for the differences between real-time and accelerated tests. The fatigue lives from accelerated tests were generally within a factor of two of the lives from real-time tests; thus, within the scope of the investigation, accelerated testing seems feasible.

Arsenic control during aquifer storage recovery cycle tests in the Floridan Aquifer.

PubMed

Mirecki, June E; Bennett, Michael W; López-Baláez, Marie C

2013-01-01

Implementation of aquifer storage recovery (ASR) for water resource management in Florida is impeded by arsenic mobilization. Arsenic, released by pyrite oxidation during the recharge phase, sometimes results in groundwater concentrations that exceed the 10 µg/L criterion defined in the Safe Drinking Water Act. ASR was proposed as a major storage component for the Comprehensive Everglades Restoration Plan (CERP), in which excess surface water is stored during the wet season, and then distributed during the dry season for ecosystem restoration. To evaluate ASR system performance for CERP goals, three cycle tests were conducted, with extensive water-quality monitoring in the Upper Floridan Aquifer (UFA) at the Kissimmee River ASR (KRASR) pilot system. During each cycle test, redox evolution from sub-oxic to sulfate-reducing conditions occurs in the UFA storage zone, as indicated by decreasing Fe(2+) /H2 S mass ratios. Arsenic, released by pyrite oxidation during recharge, is sequestered during storage and recovery by co-precipitation with iron sulfide. Mineral saturation indices indicate that amorphous iron oxide (a sorption surface for arsenic) is stable only during oxic and sub-oxic conditions of the recharge phase, but iron sulfide (which co-precipitates arsenic) is stable during the sulfate-reducing conditions of the storage and recovery phases. Resultant arsenic concentrations in recovered water are below the 10 µg/L regulatory criterion during cycle tests 2 and 3. The arsenic sequestration process is appropriate for other ASR systems that recharge treated surface water into a sulfate-reducing aquifer. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.

Physical efficiency and activity energy expenditure in term pregnancy females measured during cardiopulmonary exercise tests with a supine cycle ergometer.

PubMed

Jędrzejko, Maciej; Nowosielski, Krzysztof; Poręba, Ryszard; Ulman-Włodarz, Izabela; Bobiński, Rafał

2016-12-01

To evaluate physical efficiency and activity energy expenditure (AEE) in term pregnancy females during cardiopulmonary exercise tests with a supine cycle ergometer. The study comprised 22 healthy full-term pregnancy women with uncomplicated pregnancies hospitalized in the Department of Gynecology and Obstetrics, Specialist Teaching Hospital in Tychy, Poland. All subjects underwent cardiopulmonary exercise tests (CPET) on a supine cycle ergometer. The 12-min, three-stage, progressive, symptom-limited submaximal test protocol (up to 80% HRmax) was used. Pulsometry was used to record HR on a beat-to-beat analysis and to calculate AEE. Respiratory responses were measured by ergospirometer and a computer system on a breath-by-breath basis at rest, during exercise and at restitution. In the studied population, VO2max was established at the level of 2.19 ± 0.33 L/min in ergospirometry and 2.04 ± 025 L/min in pulsometry. Physical efficiency calculated for sub-maximal exercise by use of the Davis equation was 30.52 ± 0.12%. AEE, based on VO2 in various phases of the CPET, was 0.47, 0.71 and 0.88 L/min for phases 25, 50 and 75 W. Based on ergospirometer readouts, AEE was 10.60, 16.11 and 20.94 kJ/min for phases 25, 50 and 75 W. Overall mean AEE (determined by pulsometry) was 10.59  kJ/min. CPET testing did not have any negative effect upon the health or life of the neonates involved in the study. Submaximal CPET up to 80% HRmax with a supine cycle ergometer is a safe and precise method for assessing work efficiency in term pregnancy women.

Electromechanical conversion efficiency for dielectric elastomer generator in different energy harvesting cycles

NASA Astrophysics Data System (ADS)

Cao, Jian-Bo; E, Shi-Ju; Guo, Zhuang; Gao, Zhao; Luo, Han-Pin

2017-11-01

In order to improve electromechanical conversion efficiency for dielectric elastomer generators (DEG), on the base of studying DEG energy harvesting cycles of constant voltage, constant charge and constant electric field intensity, a new combined cycle mode and optimization theory in terms of the generating mechanism and electromechanical coupling process have been built. By controlling the switching point to achieve the best energy conversion cycle, the energy loss in the energy conversion process is reduced. DEG generating test bench which was used to carry out comparative experiments has been established. Experimental results show that the collected energy in constant voltage cycle, constant charge cycle and constant electric field intensity energy harvesting cycle decreases in turn. Due to the factors such as internal resistance losses, electrical losses and so on, actual energy values are less than the theoretical values. The electric energy conversion efficiency by combining constant electric field intensity cycle with constant charge cycle is larger than that of constant electric field intensity cycle. The relevant conclusions provide a basis for the further applications of DEG.

Use of response surface methodology in a fed-batch process for optimization of tricarboxylic acid cycle intermediates to achieve high levels of canthaxanthin from Dietzia natronolimnaea HS-1.

PubMed

Nasri Nasrabadi, Mohammad Reza; Razavi, Seyed Hadi

2010-04-01

In this work, we applied statistical experimental design to a fed-batch process for optimization of tricarboxylic acid cycle (TCA) intermediates in order to achieve high-level production of canthaxanthin from Dietzia natronolimnaea HS-1 cultured in beet molasses. A fractional factorial design (screening test) was first conducted on five TCA cycle intermediates. Out of the five TCA cycle intermediates investigated via screening tests, alfaketoglutarate, oxaloacetate and succinate were selected based on their statistically significant (P<0.05) and positive effects on canthaxanthin production. These significant factors were optimized by means of response surface methodology (RSM) in order to achieve high-level production of canthaxanthin. The experimental results of the RSM were fitted with a second-order polynomial equation by means of a multiple regression technique to identify the relationship between canthaxanthin production and the three TCA cycle intermediates. By means of this statistical design under a fed-batch process, the optimum conditions required to achieve the highest level of canthaxanthin (13172 + or - 25 microg l(-1)) were determined as follows: alfaketoglutarate, 9.69 mM; oxaloacetate, 8.68 mM; succinate, 8.51 mM. Copyright 2009 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Nickel metal hydride LEO cycle testing

NASA Technical Reports Server (NTRS)

Lowery, Eric

1995-01-01

The George C. Marshall Space Flight Center is working to characterize aerospace AB5 Nickel Metal Hydride (NiMH) cells. The cells are being evaluated in terms of storage, low earth orbit (LEO) cycling, and response to parametric testing (high rate charge and discharge, charge retention, pulse current ability, etc.). Cells manufactured by Eagle Picher are the subjects of the evaluation. There is speculation that NiMH cells may become direct replacements for current Nickel Cadmium cells in the near future.

High-cycle electromechanical aging of dielectric elastomer actuators with carbon-based electrodes

NASA Astrophysics Data System (ADS)

de Saint-Aubin, C. A.; Rosset, S.; Schlatter, S.; Shea, H.

2018-07-01

We present high-cycle aging tests of dielectric elastomer actuators (DEAs) based on silicone elastomers, reporting on the time-evolution of actuation strain and of electrode resistance over millions of cycles. We compare several types of carbon-based electrodes, and for the first time show how the choice of electrode has a dramatic influence on DEA aging. An expanding circle DEA configuration is used, consisting of a commercial silicone membrane with the following electrodes: commercial carbon grease applied manually, solvent-diluted carbon grease applied by stamping (pad printing), loose carbon black powder applied manually, carbon black powder suspension applied by inkjet-printing, and conductive silicone-carbon composite applied by stamping. The silicone-based DEAs with manually applied carbon grease electrodes show the shortest lifetime of less than 105 cycles at 5% strain, while the inkjet-printed carbon powder and the stamped silicone-carbon composite make for the most reliable devices, with lifetimes greater than 107 cycles at 5% strain. These results are valid for the specific dielectric and electrode configurations that were tested: using other dielectrics or electrode formulations would lead to different lifetimes and failure modes. We find that aging (as seen in the change in resistance and in actuation strain versus cycle number) is independent of the actuation frequency from 10 Hz to 200 Hz, and depends on the total accumulated time the DEA spends in an actuated state.

In-Plane Shear Testing of Medium and High Modulus Woven Graphite Fiber Reinforced/Polyimide Composites

NASA Technical Reports Server (NTRS)

Gentz, M.; Armentrout, D.; Rupnowski, P.; Kumosa, L.; Shin, E.; Sutter, J. K.; Kumosa, M.

2004-01-01

Iosipescu shear tests were performed at room temperature and at 316 C (600 F) o woven composites with either M40J or M60J graphite fibers and PMR-II-50 polyimide resin matrix. The composites were tested as supplied and after thermo-cycling, with the thermo-cycled composites being tested under dry and wet conditions. Acoustic emission (AE) was monitored during the room and high temperature Iosipescu experiments. The shear stresses at the maximum loads and the shear stresses at the significant onset of AE were determined for the composites as function of temperature and conditioning. The combined effects of thermo-cycling and moisture on the strength and stiffness properties of the composites were evaluated. It was determined that the room and high temperature shear stresses at the maximum loads were unaffected by conditioning. However, at room temperature the significant onset of AE was affected by conditioning; the thermal conditioned wet specimens showed the highest shear stress at the onset of AE followed by thermal-conditioned and then as received specimens. Also, at igh temperature the significant onset of AE occurred in some specimens after the maximum load due to the viscoelastoplastic nature of the matrix material.

Orbital pacing of carbon fluxes by a ∼9-My eccentricity cycle during the Mesozoic

PubMed Central

Martinez, Mathieu; Dera, Guillaume

2015-01-01

Eccentricity, obliquity, and precession are cyclic parameters of the Earth’s orbit whose climatic implications have been widely demonstrated on recent and short time intervals. Amplitude modulations of these parameters on million-year time scales induce ‟grand orbital cycles,” but the behavior and the paleoenvironmental consequences of these cycles remain debated for the Mesozoic owing to the chaotic diffusion of the solar system in the past. Here, we test for these cycles from the Jurassic to the Early Cretaceous by analyzing new stable isotope datasets reflecting fluctuations in the carbon cycle and seawater temperatures. Our results document a prominent cyclicity of ∼9 My in the carbon cycle paced by changes in the seasonal dynamics of hydrological processes and long-term sea level fluctuations. These paleoenvironmental changes are linked to a great eccentricity cycle consistent with astronomical solutions. The orbital forcing signal was mainly amplified by cumulative sequestration of organic matter in the boreal wetlands under greenhouse conditions. Finally, we show that the ∼9-My cycle faded during the Pliensbachian, which could either reflect major paleoenvironmental disturbances or a chaotic transition affecting this cycle. PMID:26417080

A model for life predictions of nickel-base superalloys in high-temperature low cycle fatigue

NASA Technical Reports Server (NTRS)

Romanoski, Glenn R.; Pelloux, Regis M.; Antolovich, Stephen D.

1988-01-01

Extensive characterization of low-cycle fatigue damage mechanisms was performed on polycrystalline Rene 80 and IN100 tested in the temperature range from 871 to 1000 C. Low-cycle fatigue life was found to be dominated by propagation of microcracks to a critical size governed by the maximum tensile stress. A model was developed which incorporates a threshold stress for crack extension, a stress-based crack growth expression, and a failure criterion. The mathematical equivalence between this mechanistically based model and the strain-life low-cycle fatigue law was demonstrated using cyclic stress-strain relationships. The model was shown to correlate the high-temperature low-cycle fatigue data of the different nickel-base superalloys considered in this study.

Physiological and perceptual responses to incremental exercise testing in healthy men: effect of exercise test modality.

PubMed

Muscat, Kristina M; Kotrach, Houssam G; Wilkinson-Maitland, Courtney A; Schaeffer, Michele R; Mendonca, Cassandra T; Jensen, Dennis

2015-11-01

In a randomized cross-over study of 15 healthy men aged 20-30 years, we compared physiological and perceptual responses during treadmill and cycle exercise test protocols matched for increments in work rate - the source of increased locomotor muscle metabolic and contractile demands. The rates of O2 consumption and CO2 production were higher at the peak of treadmill versus cycle testing (p ≤ 0.05). Nevertheless, work rate, minute ventilation, tidal volume (VT), breathing frequency (fR), inspiratory capacity (IC), inspiratory reserve volume (IRV), tidal esophageal (Pes,tidal) and transdiaphragmatic pressure swings (Pdi,tidal), peak expiratory gastric pressures (Pga,peak), the root mean square of the diaphragm electromyogram (EMGdi,rms) expressed as a percentage of maximum EMGdi,rms (EMGdi,rms%max), and dyspnea ratings were similar at the peak of treadmill versus cycle testing (p > 0.05). Ratings of leg discomfort were higher at the peak of cycle versus treadmill exercise (p ≤ 0.05), even though peak O2 consumption was lower during cycling. Oxygen consumption, CO2 production, minute ventilation, fR, Pes,tidal, Pdi,tidal and Pga,peak were higher (p ≤ 0.05), while VT, IC, IRV, EMGdi,rms%max, and ratings of dyspnea and leg discomfort were similar (p > 0.05) at all or most submaximal work rates during treadmill versus cycle exercise. Our findings highlight important differences (and similarities) in physiological and perceptual responses at maximal and submaximal work rates during incremental treadmill and cycle exercise testing protocols. The lack of effect of exercise test modality on peak work rate advocates for the use of this readily available parameter to optimize training intensity determination, regardless of exercise training mode.

Hot fire test results of subscale tubular combustion chambers

NASA Technical Reports Server (NTRS)

Kazaroff, John M.; Jankovsky, Robert S.; Pavli, Albert J.

1992-01-01

Advanced, subscale, tubular combustion chambers were built and test fired with hydrogen-oxygen propellants to assess the increase in fatigue life that can be obtained with this type of construction. Two chambers were tested: one ran for 637 cycles without failing, compared to a predicted life of 200 cycles for a comparable smooth-wall milled-channel liner configuration. The other chamber failed at 256 cycles, compared to a predicted life of 118 cycles for a comparable smooth-wall milled-channel liner configuration. Posttest metallographic analysis determined that the strain-relieving design (structural compliance) of the tubular configuration was the cause of this increase in life.

Environmental qualification testing of payload G-534, the Pool Boiling Experiment

NASA Technical Reports Server (NTRS)

Sexton, J. Andrew

1992-01-01

Payload G-534, the prototype Pool Boiling Experiment (PBE), is scheduled to fly on the STS-47 mission in September 1992. This paper describes the purpose of the experiment and the environmental qualification testing program that was used to prove the integrity of the hardware. Component and box level vibration and thermal cycling tests were performed to give an early level of confidence in the hardware designs. At the system level, vibration, thermal extreme soaks, and thermal vacuum cycling tests were performed to qualify the complete design for the expected shuttle environment. The system level vibration testing included three axis sine sweeps and random inputs. The system level hot and cold soak tests demonstrated the hardware's capability to operate over a wide range of temperatures and gave wider latitude in determining which shuttle thermal attitudes were compatible with the experiment. The system level thermal vacuum cycling tests demonstrated the hardware's capability to operate in a convection free environment. A unique environmental chamber was designed and fabricated by the PBE team and allowed most of the environmental testing to be performed within the hardware build laboratory. The completion of the test program gave the project team high confidence in the hardware's ability to function as designed during flight.

Chopper-controlled discharge life cycling studies on lead-acid batteries

NASA Technical Reports Server (NTRS)

Kraml, J. J.; Ames, E. P.

1982-01-01

State-of-the-art 6 volt lead-acid golf car batteries were tested. A daily charge/discharge cycling to failure points under various chopper controlled pulsed dc and continuous current load conditions was undertaken. The cycle life and failure modes were investigated for depth of discharge, average current chopper frequency, and chopper duty cycle. It is shown that battery life is primarily and inversely related to depth of discharge and discharge current. Failure mode is characterized by a gradual capacity loss with consistent evidence of cell element aging.

Modern fertility awareness methods: Wrist wearables capture the changes of temperature associated with the menstrual cycle.

PubMed

Shilaih, Mohaned; Goodale, Brianna M; Falco, Lisa; Kübler, Florian; De Clerck, Valerie; Leeners, Brigitte

2017-11-24

Core and peripheral body temperatures are affected by changes in reproductive hormones during the menstrual cycle. Women worldwide use the basal body temperature (BBT) method to aid and prevent conception. However, prior research suggests taking one's daily temperature can prove inconvenient and subject to environmental factors. We investigate whether a more automatic, non-invasive temperature measurement system can detect changes in temperature across the menstrual cycle. We examined how wrist-skin temperature (WST), measured with wearable sensors, correlates with urinary tests of ovulation and may serve as a new method of fertility tracking. One hundred and thirty-six eumenorrheic, non-pregnant women participated in an observational study. Participants wore WST biosensors during sleep and reported their daily activities. An at-home luteinizing hormone test was used to confirm ovulation. WST was recorded across 437 cycles (mean cycles/participant=3.21, S.D.=2.25). We tested the relationship between the fertile window and WST temperature shifts, using the BBT three-over-six rule. A sustained three-day temperature shift was observed in 357/437 cycles (82%), with the lowest cycle temperature occurring in the fertile window 41% of the time. Most temporal shifts (307/357, 86%) occurred on ovulation day or later. The average early-luteal phase temperature was 0.33°C higher than in the fertile window. Menstrual cycle changes in WST were impervious to lifestyle factors, like having sex, alcohol or eating prior to bed, that, in prior work, have been shown to obfuscate BBT readings. Although currently costlier than BBT, this study suggests that WST could be a promising, convenient parameter for future multi-parameter fertility-awareness methods. ©2017 The Author(s).

Effect of storage in artificial saliva and thermal cycling on Knoop hardness of resin denture teeth.

PubMed

Assunção, Wirley Gonçalves; Gomes, Erica Alves; Barão, Valentim Adelino Ricardo; Barbosa, Débora Barros; Delben, Juliana Aparecida; Tabata, Lucas Fernando

2010-07-01

This study aimed to evaluate the effect of different storage periods in artificial saliva and thermal cycling on Knoop hardness of 8 commercial brands of resin denture teeth. Eigth different brands of resin denture teeth were evaluated (Artplus group, Biolux group, Biotone IPN group, Myerson group, SR Orthosit group, Trilux group, Trubyte Biotone group, and Vipi Dent Plus group). Twenty-four teeth of each brand had their occlusal surfaces ground flat and were embedded in autopolymerized acrylic resin. After polishing, the teeth were submitted to different conditions: (1) immersion in distilled water at 37+/-2 degrees C for 48+/-2h (control); (2) storage in artificial saliva at 37+/-2 degrees C for 15, 30 and 60 days, and (3) thermal cycling between 5 and 55 degrees C with 30-s dwell times for 5000 cycles. Knoop hardness test was performed after each condition. Data were analyzed with two-way ANOVA and Tukey's test (alpha=.05). In general, SR Orthosit group presented the highest statistically significant Knoop hardness value while Myerson group exhibited the smallest statistically significant mean (P<.05) in the control period, after thermal cycling, and after all storage periods. The Knoop hardness means obtained before thermal cycling procedure (20.34+/-4.45 KHN) were statistically higher than those reached after thermal cycling (19.77+/-4.13 KHN). All brands of resin denture teeth were significantly softened after storage period in artificial saliva. Storage in saliva and thermal cycling significantly reduced the Knoop hardness of the resin denture teeth. SR Orthosit denture teeth showed the highest Knoop hardness values regardless the condition tested. Copyright 2010 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

An innovative cycling exergame to promote cardiovascular fitness in youth with cerebral palsy.

PubMed

Knights, Shannon; Graham, Nicholas; Switzer, Lauren; Hernandez, Hamilton; Ye, Zi; Findlay, Briar; Xie, Wen Yan; Wright, Virginia; Fehlings, Darcy

2016-01-01

To evaluate the effects of an internet-platform exergame cycling programme on cardiovascular fitness of youth with cerebral palsy (CP). In this pilot prospective case series, eight youth with bilateral spastic CP, Gross Motor Functional Classification System (GMFCS) level III, completed a six-week exergame programme. Outcomes were obtained at baseline and post-intervention. The primary outcome measure was the GMFCS III-specific shuttle run test (SRT-III). Secondary outcomes included health-related quality of life (HQL) as measured by the KIDSCREEN-52 questionnaire, six-minute walk test, Wingate arm cranking test and anthropomorphic measurements. There were significant improvements in the SRT-III (t = -2.5, p = 0.04, d = 0.88) post-intervention. There were no significant changes in secondary outcomes. An exergame cycling programme may lead to improvement in cardiovascular fitness in youth with CP. This study was limited by small sample size and lack of a comparison group. Future research is warranted.

Energy efficient engine, high pressure turbine thermal barrier coating. Support technology report

NASA Technical Reports Server (NTRS)

Duderstadt, E. C.; Agarwal, P.

1983-01-01

This report describes the work performed on a thermal barrier coating support technology task of the Energy Efficient Engine Component Development Program. A thermal barrier coating (TBC) system consisting of a Ni-Cr-Al-Y bond cost layer and ZrO2-Y2O3 ceramic layer was selected from eight candidate coating systems on the basis of laboratory tests. The selection was based on coating microstructure, crystallographic phase composition, tensile bond and bend test results, erosion and impact test results, furnace exposure, thermal cycle, and high velocity dynamic oxidation test results. Procedures were developed for applying the selected TBC to CF6-50, high pressure turbine blades and vanes. Coated HPT components were tested in three kinds of tests. Stage 1 blades were tested in a cascade cyclic test rig, Stage 2 blades were component high cycle fatigue tested to qualify thermal barrier coated blades for engine testing, and Stage 2 blades and Stage 1 and 2 vanes were run in factory engine tests. After completion of the 1000 cycle engine test, the TBC on the blades was in excellent condition over all of the platform and airfoil except at the leading edge above midspan on the suction side of the airfoil. The coating damage appeared to be caused by particle impingement; adjacent blades without TBC also showed evidence of particle impingement.

A generalized memory test algorithm

NASA Technical Reports Server (NTRS)

Milner, E. J.

1982-01-01

A general algorithm for testing digital computer memory is presented. The test checks that (1) every bit can be cleared and set in each memory work, and (2) bits are not erroneously cleared and/or set elsewhere in memory at the same time. The algorithm can be applied to any size memory block and any size memory word. It is concise and efficient, requiring the very few cycles through memory. For example, a test of 16-bit-word-size memory requries only 384 cycles through memory. Approximately 15 seconds were required to test a 32K block of such memory, using a microcomputer having a cycle time of 133 nanoseconds.

40 CFR 91.118 - Certification procedure-testing.

Code of Federal Regulations, 2014 CFR

2014-07-01

... difference between the old FEL and the new FEL; and that the new FEL applies to all engines covered by the... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Standards and Certification... test engine using the specified test procedures and appropriate test cycle. All test results must be...

40 CFR 91.118 - Certification procedure-testing.

Code of Federal Regulations, 2012 CFR

2012-07-01

... difference between the old FEL and the new FEL; and that the new FEL applies to all engines covered by the... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Standards and Certification... test engine using the specified test procedures and appropriate test cycle. All test results must be...

40 CFR 91.118 - Certification procedure-testing.

Code of Federal Regulations, 2011 CFR

2011-07-01

... difference between the old FEL and the new FEL; and that the new FEL applies to all engines covered by the... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Standards and Certification... test engine using the specified test procedures and appropriate test cycle. All test results must be...

40 CFR 91.118 - Certification procedure-testing.

Code of Federal Regulations, 2010 CFR

2010-07-01

... difference between the old FEL and the new FEL; and that the new FEL applies to all engines covered by the... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Standards and Certification... test engine using the specified test procedures and appropriate test cycle. All test results must be...

40 CFR 91.118 - Certification procedure-testing.

Code of Federal Regulations, 2013 CFR

2013-07-01

... difference between the old FEL and the new FEL; and that the new FEL applies to all engines covered by the... (CONTINUED) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Emission Standards and Certification... test engine using the specified test procedures and appropriate test cycle. All test results must be...

Low-cost directionally-solidified turbine blades, volume 2. [TFE731-3 turbofan engine

NASA Technical Reports Server (NTRS)

Dennis, R. E.; Hoppin, G. S., III; Hurst, L. G.

1979-01-01

An endothermically heated technology was used to manufacture low cost, directionally solidified, uncooled nickel-alloy blades for the TFE731-3 turbofan engine. The MAR-M 247 and MER-M 100+Hf blades were finish processed through heat treatment, machining, and coating operations prior to 150 hour engine tests consisting of the following sequences: (1) 50 hours of simulated cruise cycling (high fatigue evaluation); (2) 50 hours at the maximum continuous power rating (stress rupture endurance (low cycle fatigue). None of the blades visually showed any detrimental effects from the test. This was verified by post test metallurgical evaluation. The specific fuel consumption was reduced by 2.4% with the uncooled blades.

40 CFR 86.1360-2007 - Supplemental emission test; test cycle and procedures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 20 2012-07-01 2012-07-01 false Supplemental emission test; test cycle and procedures. 86.1360-2007 Section 86.1360-2007 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Emission Regulations...

40 CFR 86.1360-2007 - Supplemental emission test; test cycle and procedures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 20 2013-07-01 2013-07-01 false Supplemental emission test; test cycle and procedures. 86.1360-2007 Section 86.1360-2007 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES (CONTINUED) Emission Regulations...

HALT to qualify electronic packages: a proof of concept

NASA Astrophysics Data System (ADS)

Ramesham, Rajeshuni

2014-03-01

A proof of concept of the Highly Accelerated Life Testing (HALT) technique was explored to assess and optimize electronic packaging designs for long duration deep space missions in a wide temperature range (-150°C to +125°C). HALT is a custom hybrid package suite of testing techniques using environments such as extreme temperatures and dynamic shock step processing from 0g up to 50g of acceleration. HALT testing used in this study implemented repetitive shock on the test vehicle components at various temperatures to precipitate workmanship and/or manufacturing defects to show the weak links of the designs. The purpose is to reduce the product development cycle time for improvements to the packaging design qualification. A test article was built using advanced electronic package designs and surface mount technology processes, which are considered useful for a variety of JPL and NASA projects, i.e. (surface mount packages such as ball grid arrays (BGA), plastic ball grid arrays (PBGA), very thin chip array ball grid array (CVBGA), quad flat-pack (QFP), micro-lead-frame (MLF) packages, several passive components, etc.). These packages were daisy-chained and independently monitored during the HALT test. The HALT technique was then implemented to predict reliability and assess survivability of these advanced packaging techniques for long duration deep space missions in much shorter test durations. Test articles were built using advanced electronic package designs that are considered useful in various NASA projects. All the advanced electronic packages were daisychained independently to monitor the continuity of the individual electronic packages. Continuity of the daisy chain packages was monitored during the HALT testing using a data logging system. We were able to test the boards up to 40g to 50g shock levels at temperatures ranging from +125°C to -150°C. The HALT system can deliver 50g shock levels at room temperature. Several tests were performed by subjecting the test boards to various g levels ranging from 5g to 50g, test durations of 10 minutes to 60 minutes, hot temperatures of up to +125°C and cold temperatures down to -150°C. During the HALT test, electrical continuity measurements of the PBGA package showed an open-circuit, whereas the BGA, MLF, and QFPs showed signs of small variations of electrical continuity measurements. The electrical continuity anomaly of the PBGA occurred in the test board within 12 hours of commencing the accelerated test. Similar test boards were assembled, thermal cycled independently from -150°C to +125°C and monitored for electrical continuity through each package design. The PBGA package on the test board showed an anomalous electrical continuity behavior after 959 thermal cycles. Each thermal cycle took around 2.33 hours, so that a total test time to failure of the PBGA was 2,237 hours (or ~3.1 months) due to thermal cycling alone. The accelerated technique (thermal cycling + shock) required only 12 hours to cause a failure in the PBGA electronic package. Compared to the thermal cycle only test, this was an acceleration of ~186 times (more than 2 orders of magnitude). This acceleration process can save significant time and resources for predicting the life of a package component in a given environment, assuming the failure mechanisms are similar in both the tests. Further studies are in progress to make systematic evaluations of the HALT technique on various other advanced electronic packaging components on the test board. With this information one will be able to estimate the number of mission thermal cycles to failure with a much shorter test program. Further studies are in progress to make systematic study of various components, constant temperature range for both the tests. Therefore, one can estimate the number of hours to fail in a given thermal and shock levels for a given test board physical properties.

Lead-acid batteries in solar photovoltaic power systems for marine aids to navigation. Final report

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

Trenchard, S.E.

1981-10-01

Since 1974, the U.S. Coast Guard has been testing lead-acid batteries in solar photovoltaic-powered systems for aids to navigation. Three types of lead-acid batteries, distinguished by the composition of their grid material, have been tested: lead-antimony grid, lead-calcium grid, and pure-lead grid. This report contains a comparison of the charging characteristics and the charge-discharge cycling behavior of each grid type. All types were remarkably similar qualitatively in their daily as well as annual cycling behavior but the significance of the quantitative differences offer distinctive tradeoffs. This report presents models for water usage, depth-of-discharge, and post-cycle capacity for various levels ofmore » voltage regulation. Based on the post-cycle capacity tests, the effect of grid strength, grid thickness, and operating conditions on life expectancy are presented. A final discussion presents the results of a field deployment of solar photovoltaic-powered aids to navigation in the Miami, Florida area. Potential solutions to the battery terminal corrosion and bird guano problems observed are discussed.« less

Improved glucose tolerance and insulin sensitivity after electrical stimulation-assisted cycling in people with spinal cord injury.

PubMed

Jeon, J Y; Weiss, C B; Steadward, R D; Ryan, E; Burnham, R S; Bell, G; Chilibeck, P; Wheeler, G D

2002-03-01

Longitudinal training. The purpose was to determine the effect of electrical stimulation (ES)-assisted cycling (30 min/day, 3 days/week for 8 weeks) on glucose tolerance and insulin sensitivity in people with spinal cord injury (SCI). The Steadward Centre, Alberta, Canada. Seven participants with motor complete SCI (five males and two females aged 30 to 53 years, injured 3-40 years, C5-T10) underwent 2-h oral glucose tolerance tests (OGTT, n=7) and hyperglycaemic clamp tests (n=3) before and after 8 weeks of training with ES-assisted cycling. Results indicated that subjects' glucose level were significantly lower at 2 h OGTT following 8 weeks of training (122.4+/-10 vs 139.9+/-16, P=0.014). Two-hour hyperglycaemic clamps tests showed improvement in all three people for glucose utilisation and in two of three people for insulin sensitivity. These results suggested that exercise with ES-assisted cycling is beneficial for the prevention and treatment of Type 2 diabetes mellitus in people with SCI. Supported by Alberta Paraplegic Foundation, Therapeutic Alliance.

Long-term high-velocity oxidation and hot corrosion testing of several NiCrAl and FeCrAl base oxide dispersion strengthened alloys

NASA Technical Reports Server (NTRS)

Lowell, C. E.; Deadmore, D. L.; Whittenberger, J. D.

1982-01-01

Several oxide dispersion strengthened (ODS) alloys have been tested for cyclic, long-term, high gas-velocity resistance to oxidation at 1100 C and hot corrosion at 900 C. Both nominally Ni-16Cr-4Al and Fe-20Cr-4.5Al ODS alloys were subjected up to about 2500 cycles, where each cycle consisted of 1 hr in a hot, Mach 0.3 combusted gas stream followed by a 3-min quench in an ambient temperature, Mach 0.3 air blast. For comparison to existing technology, a coated superalloy was simultaneously tested. The ODS iron alloy exhibited clearly superior behavior, surviving 3800 oxidation and 2300 hot corrosion cycles essentially unscathed. While the ODS nickel alloys exhibited adequate oxidation resistance, the long-term hot corrosion resistance could be marginal, since the best life for such alloys under these conditions was only about 1100 cycles. However, the hot corrosion resistance of the ODS Ni-base alloys is excellent in comparison to that of traditional superalloys.

LTP varies across the estrous cycle: enhanced synaptic plasticity in proestrus rats.

PubMed

Warren, S G; Humphreys, A G; Juraska, J M; Greenough, W T

1995-12-12

Previous studies have shown that the number of dendritic spines and synapses in hippocampal CA1 stratum radiatum decreases more than 30% between the proestrus (high estrogen) and estrus (low estrogen) phases of the rat estrous cycle [10,27]. In the present study, we investigated whether hippocampal synaptic plasticity, as measured by long-term potentiation (LTP), might also vary across the estrous cycle of the female rat. Male rats, and female rats at each phase of the estrous cycle were tested in either the morning or afternoon. There were no significant group differences in the pre-LTP I/O curves. However, females examined during the afternoon of proestrus, the phase during which prior studies indicate synapse number to be highest, demonstrated the greatest degree of potentiation. Diestrus, proestrus and estrus females tested in the morning demonstrated similar amounts of potentiation. There were also significant differences in post-LTP I/O curves between the afternoon proestrus females and males tested in the afternoon. These results suggest that gonadal hormones, interacting with the time of day, may regulate neural processes underlying learning and memory.

40 CFR 86.1427 - Certification Short Test procedure; overview.

Code of Federal Regulations, 2010 CFR

2010-07-01

... loaded modes. Specific conditions defined by this test procedure include fuel characteristics, ambient... CO fuel, a moderate temperature test with Cold CO fuel, and a warm temperature test with FTP Otto-cycle test fuel, as described in table O-96-1 of § 86.1430. The manufacturer must complete testing for...

40 CFR 86.1427 - Certification Short Test procedure; overview.

Code of Federal Regulations, 2013 CFR

2013-07-01

... loaded modes. Specific conditions defined by this test procedure include fuel characteristics, ambient... CO fuel, a moderate temperature test with Cold CO fuel, and a warm temperature test with FTP Otto-cycle test fuel, as described in table O-96-1 of § 86.1430. The manufacturer must complete testing for...

40 CFR 86.1427 - Certification Short Test procedure; overview.

Code of Federal Regulations, 2011 CFR

2011-07-01

... loaded modes. Specific conditions defined by this test procedure include fuel characteristics, ambient... CO fuel, a moderate temperature test with Cold CO fuel, and a warm temperature test with FTP Otto-cycle test fuel, as described in table O-96-1 of § 86.1430. The manufacturer must complete testing for...

40 CFR 86.1427 - Certification Short Test procedure; overview.

Code of Federal Regulations, 2012 CFR

2012-07-01

... loaded modes. Specific conditions defined by this test procedure include fuel characteristics, ambient... CO fuel, a moderate temperature test with Cold CO fuel, and a warm temperature test with FTP Otto-cycle test fuel, as described in table O-96-1 of § 86.1430. The manufacturer must complete testing for...

Durability of building stones against artificial salt crystallization

NASA Astrophysics Data System (ADS)

Min, K.; Park, J.; Han, D.

2005-12-01

Salts have been known as the most powerful weathering agents, especially when combined with frost action. Salt crystallization test along with freezing-thawing test and acid immersion test was carried out to assess the durability of building stones against weathering. Granite, limestone, marble and basalt were sampled from different quarries in south Korea for this study. One cycle of artificial salt crystallization test was composed of immersion of cored rock specimens in oversaturated solutions of CaCl2, KCl, NaCl and Na2SO4, respectively for 15 hours and successive drying in an oven of 105°C for 3 hours and cooling at room temperature. Tests were performed up to 30 cycles, and specific gravity and ultrasonic velocity were measured after experiencing every 10 cycles and uniaxial compressive strength was measured only after 30 cycles. During the repeated Na2SO4 salt crystallization, some rock samples were gradually deformed excessively and burst after 20 to 30 cycles of test. The variation patterns of physical properties during the salt crystallization tests are too variable to generalize the effect of salt weathering on physical properties but limestone, marble and basalt samples showed relatively greater change of physical properties than granite samples. The recrystallized salts were well observed in the cracks of rock samples through the scanning electron microscope. In the all salt crystallization tests, apparent specific gravities for all tested samples increased generally but not so significantly due to recrystallization of salts. It can be inferred that filling the pores with salt crystals cause the increase of ultrasonic velocity during the early stage of salt crystallization and then in later stages the repeated cycles of salt crystallization result in development of cracks leading decrease of ultrasonic velocity for some rock samples.

Comparison of Battery Life Across Real-World Automotive Drive-Cycles (Presentation)

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

Smith, K.; Earleywine, M.; Wood, E.

2011-11-01

Laboratories run around-the-clock aging tests to try to understand as quickly as possible how long new Li-ion battery designs will last under certain duty cycles. These tests may include factors such as duty cycles, climate, battery power profiles, and battery stress statistics. Such tests are generally accelerated and do not consider possible dwell time at high temperatures and states-of-charge. Battery life-predictive models provide guidance as to how long Li-ion batteries may last under real-world electric-drive vehicle applications. Worst-case aging scenarios are extracted from hundreds of real-world duty cycles developed from vehicle travel surveys. Vehicles examined included PHEV10 and PHEV40 EDVsmore » under fixed (28 degrees C), limited cooling (forced ambient temperature), and aggressive cooling (20 degrees C chilled liquid) scenarios using either nightly charging or opportunity charging. The results show that battery life expectancy is 7.8 - 13.2 years for the PHEV10 using a nightly charge in Phoenix, AZ (hot climate), and that the 'aggressive' cooling scenario can extend battery life by 1-3 years, while the 'limited' cooling scenario shortens battery life by 1-2 years. Frequent (opportunity) charging can reduce battery life by 1 year for the PHEV10, while frequent charging can extend battery life by one-half year.« less

40 CFR 600.209-08 - Calculation of vehicle-specific 5-cycle fuel economy values for a model type.

Code of Federal Regulations, 2013 CFR

2013-07-01

... intended for sale at high altitude, the Administrator may use fuel economy data from tests conducted on... from the tests performed using gasoline or diesel test fuel. (ii) If 5-cycle testing was performed on the alcohol or natural gas test fuel, calculate the city and highway fuel economy values from the...

40 CFR 600.209-08 - Calculation of vehicle-specific 5-cycle fuel economy values for a model type.

Code of Federal Regulations, 2012 CFR

2012-07-01

... intended for sale at high altitude, the Administrator may use fuel economy data from tests conducted on... from the tests performed using gasoline or diesel test fuel. (ii) If 5-cycle testing was performed on the alcohol or natural gas test fuel, calculate the city and highway fuel economy values from the...

High-impact strength acrylic denture base material processed by autoclave.

PubMed

Abdulwahhab, Salwan Sami

2013-10-01

To investigate the effect of two different cycles of autoclave processing on the transverse strength, impact strength, surface hardness and the porosity of high-impact strength acrylic denture base material. High Impact Acryl was the heat-cured acrylic denture base material included in the study. A total of 120 specimens were prepared, the specimens were grouped into: control groups in which high-impact strength acrylic resins processed by conventional water-bath processing technique (74°C for 1.5 h then boil for 30 min) and experimental groups in which high-impact strength acrylic resins processed by autoclave at 121°C, 210 kPa .The experimental groups were divided into (fast) groups for 15 min, and (slow) groups for 30 min. To study the effect of the autoclave processing (Tuttnauer 2540EA), four tests were conducted transverse strength (Instron universal testing machine), impact strength (Charpy tester), surface hardness (shore D), and porosity test. The results were analyzed to ANOVA and LSD test. In ANOVA test, there were highly significant differences between the results of the processing techniques in transverse, impact, hardness, and porosity test. The LSD test showed a significant difference between control and fast groups in transverse and hardness tests and a non-significant difference in impact test and a highly significant difference in porosity test; while, there were a highly significant differences between control and slow groups in all examined tests; finally, there were a non-significant difference between fast and slow groups in transverse and porosity tests and a highly significant difference in impact and hardness tests. In the autoclave processing technique, the slow (long) curing cycle improved the tested physical and mechanical properties as compared with the fast (short) curing cycle. The autoclave processing technique improved the tested physical and mechanical properties of High Impact Acryl. Copyright © 2013 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Thermal-fatigue and oxidation resistance of cobalt-modified Udimet 700 alloy

NASA Technical Reports Server (NTRS)

Bizon, P. T.; Barrow, B. J.

1986-01-01

Comparative thermal-fatigue and oxidation resistances of cobalt-modified wrought Udimet 700 alloy (obtained by reducing the cobalt level by direct substitution of nickel) were determined from fluidized-bed tests. Bed temperatures were 1010 and 288 C (1850 and 550 C) for the first 5500 symmetrical 6-min cycles. From cycle 5501 to the 14000-cycle limit of testing, the heating bed temperature was increased to 1050 C (1922 F). Cobalt levels between 0 and 17 wt% were studied in both the bare and NiCrAlY overlay coated conditions. A cobalt level of about 8 wt% gave the best thermal-fatigue life. The conventional alloy specification is for 18.5% cobalt, and hence, a factor of 2 in savings of cobalt could be achieved by using the modified alloy. After 13500 cycles, all bare cobalt-modified alloys lost 10 to 13 percent of their initial weight. Application of the NiCrAlY overlay coating resulted in weight losses of 1/20 to 1/100 of that of the corresponding bare alloy.

Sodium-sulfur technology evaluation at Argonne National Laboratory

NASA Astrophysics Data System (ADS)

Mulcahey, T. P.; Tummillo, A. F.; Hogrefe, R. L.; Christianson, C. C.; Biwer, R.; Webster, C. E.; Lee, J.; Miller, J. F.; Marr, J. J.; Smaga, J. A.

The Analysis and Diagnostics Laboratory (ADL) at Argonne National Laboratory has completed evaluation of the Ford Aerospace and Communication Corp. (FACC) technology in the form of four load-levelling (LL) cells, five electric vehicle (EV) cells, and a sub-battery of 89 series connected EV cells. The ADL also has initiated evaluation of the Chloride Silent Power Limited (CSPL) sodium-sulfur (PB) battery technology in the form of 8 individual cells. The evaluation of the FACC-LL cells consisted of an abbreviated performance characterization followed by life-cycle tests on two individual cells and life-cycle tests only on the two other individual cells. The evaluation indicated that the technology was improving, but long-term (life) reliability was not yet adequate for utility applications. The cells exhibited individual cycle lives ranging from 659 to over 1366 cycles, which is equivalent to 2 1/2 to 5 1/2 years in utility use. It was also found that full-cell capacity could only be maintained by applying a special charge regime, regularly or periodically, that consisted of a constant-current followed by a constant-voltage.

Lean Development with the Morpheus Simulation Software

NASA Technical Reports Server (NTRS)

Brogley, Aaron C.

2013-01-01

The Morpheus project is an autonomous robotic testbed currently in development at NASA's Johnson Space Center (JSC) with support from other centers. Its primary objectives are to test new 'green' fuel propulsion systems and to demonstrate the capability of the Autonomous Lander Hazard Avoidance Technology (ALHAT) sensor, provided by the Jet Propulsion Laboratory (JPL) on a lunar landing trajectory. If successful, these technologies and lessons learned from the Morpheus testing cycle may be incorporated into a landing descent vehicle used on the moon, an asteroid, or Mars. In an effort to reduce development costs and cycle time, the project employs lean development engineering practices in its development of flight and simulation software. The Morpheus simulation makes use of existing software packages where possible to reduce the development time. The development and testing of flight software occurs primarily through the frequent test operation of the vehicle and incrementally increasing the scope of the test. With rapid development cycles, risk of loss of the vehicle and loss of the mission are possible, but efficient progress in development would not be possible without that risk.

Research on optimization of test cycles for comfort to the special vehicles

NASA Astrophysics Data System (ADS)

Mitroi, Marian; Chiru, Anghel

2017-10-01

The comfort of vehicles, regardless of their type is represent a requirement to by fulfilled in the context of current technological developments special vehicles generally move under different soil, time, or season conditions, and the land in which the vehicles move is complex and varied in the physical structure. Due to the high level of involvement in the driveability, safety and comfort of automotive, suspension system is a key factor with major implications for vibration and noise, affecting the human body. The objective of the research is related to determining the test cycles of special vehicles that are approaching real situations, to determine the level of comfort. The evaluate of the degree of comfort will be realized on acceleration values recorded, especially the vertical ones that have the highest influence on the human body. Thus, in this way the tests can be established needed to determine the level of comfort required for each particular type of special vehicle. The utility of the test cycles to optimize comfort is given to the accurate identification of the specific test needs, depending on the each vehicle.

T55-L-712 turbine engine compressor housing refurbishment-plasma spray project

NASA Technical Reports Server (NTRS)

Leissler, George W.; Yuhas, John S.

1988-01-01

A study was conducted to assess the feasibility of reclaiming T55-L-712 turbine engine compressor housings with an 88 wt percent aluminum to 12 wt percent silicon alloy applied by a plasma spray process. Tensile strength testing was conducted on as-sprayed and thermally cycled test specimens which were plasma sprayed with 0.020 to 0.100 in. coating thicknesses. Satisfactory tensile strength values were observed in the as-sprayed tensile specimens. There was essentially no decrease in tensile strength after thermally cycling the tensile specimens. Furthermore, compressor housings were plasma sprayed and thermally cycled in a 150-hr engine test and a 200-hr actual flight test during which the turbine engine was operated at a variety of loads, speeds and torques. The plasma sprayed coating system showed no evidence of degradation or delamination from the compressor housings. As a result of these tests, a procedure was designed and developed for the application of an aluminum-silicon alloy in order to reclaim T55-L-712 turbine engine compressor housings.

Plausibility of Menstrual Cycle Apps Claiming to Support Conception.

PubMed

Freis, Alexander; Freundl-Schütt, Tanja; Wallwiener, Lisa-Maria; Baur, Sigfried; Strowitzki, Thomas; Freundl, Günter; Frank-Herrmann, Petra

2018-01-01

The interval of peak fertility during the menstrual cycle is of limited duration, and the day of ovulation varies, even in women with fairly regular cycles. Therefore, menstrual cycle apps identifying the "fertile window" for women trying to conceive must be quite precise. A deviation of a few days may lead the couple to focus on less- or non-fertile days for sexual intercourse and thus may be worse than random intercourse. The aim of the present investigation was to develop a scoring system for rating available apps for determining the fertile window and secondarily pilot test 12 apps currently available in both German and English (consisting of 6 calendar-based apps: Clue Menstruations- und Zykluskalender, Flo Menstruationskalender, Maya-Mein Periodentracker, Menstruationskalender Pro, Period Tracker Deluxe, and WomanLog-Pro-Kalender; 2 calculothermal apps: Ovy and Natural Cycles; and 4 symptothermal apps: myNFP, Lady Cycle, Lily, and OvuView). The calendar-based apps were investigated by entering several series of cycles with varying lengths, whereas the symptom-based apps were examined by entering data of cycles with known temperature rise, cervical mucus pattern, and clinical ovulation. The main criteria for evaluating the cycle apps were as follows: (1) What methods/parameters were used to determine the fertile window? (2) What study results exist concerning that underlying method/parameters? (3) What study results exist concerning the app itself? (4) Was there a qualified counseling service? The calendar-based apps predicted the fertile days based on data of previous cycles. They obtained zero points in our scoring system, as they did not comply with any of the evaluated criteria. Calculothermal apps had similar deficits for predicting the most fertile days and produced suboptimal results (Ovy 3/30 points and Natural Cycles 2/30 points). The symptothermal apps determined the fertile days based on parameters of the current cycle: Lady Cycle scored 20/30 points, myNFP 20/30 points, Lily 19/30 points, and OvuView 11/30 points. We concluded that the available cycle apps vary according to their underlying scientific quality and clear rating criteria have been suggested. Three of the tested apps were judged to be eligible for further study. The scientific evaluation of cycle apps depends on good prospective studies undertaken by independent investigators who are free of commercial bias.

Plausibility of Menstrual Cycle Apps Claiming to Support Conception

PubMed Central

Freis, Alexander; Freundl-Schütt, Tanja; Wallwiener, Lisa-Maria; Baur, Sigfried; Strowitzki, Thomas; Freundl, Günter; Frank-Herrmann, Petra

2018-01-01

The interval of peak fertility during the menstrual cycle is of limited duration, and the day of ovulation varies, even in women with fairly regular cycles. Therefore, menstrual cycle apps identifying the “fertile window” for women trying to conceive must be quite precise. A deviation of a few days may lead the couple to focus on less- or non-fertile days for sexual intercourse and thus may be worse than random intercourse. The aim of the present investigation was to develop a scoring system for rating available apps for determining the fertile window and secondarily pilot test 12 apps currently available in both German and English (consisting of 6 calendar-based apps: Clue Menstruations- und Zykluskalender, Flo Menstruationskalender, Maya-Mein Periodentracker, Menstruationskalender Pro, Period Tracker Deluxe, and WomanLog-Pro-Kalender; 2 calculothermal apps: Ovy and Natural Cycles; and 4 symptothermal apps: myNFP, Lady Cycle, Lily, and OvuView). The calendar-based apps were investigated by entering several series of cycles with varying lengths, whereas the symptom-based apps were examined by entering data of cycles with known temperature rise, cervical mucus pattern, and clinical ovulation. The main criteria for evaluating the cycle apps were as follows: (1) What methods/parameters were used to determine the fertile window? (2) What study results exist concerning that underlying method/parameters? (3) What study results exist concerning the app itself? (4) Was there a qualified counseling service? The calendar-based apps predicted the fertile days based on data of previous cycles. They obtained zero points in our scoring system, as they did not comply with any of the evaluated criteria. Calculothermal apps had similar deficits for predicting the most fertile days and produced suboptimal results (Ovy 3/30 points and Natural Cycles 2/30 points). The symptothermal apps determined the fertile days based on parameters of the current cycle: Lady Cycle scored 20/30 points, myNFP 20/30 points, Lily 19/30 points, and OvuView 11/30 points. We concluded that the available cycle apps vary according to their underlying scientific quality and clear rating criteria have been suggested. Three of the tested apps were judged to be eligible for further study. The scientific evaluation of cycle apps depends on good prospective studies undertaken by independent investigators who are free of commercial bias. PMID:29666788

Duodenoscope reprocessing surveillance with adenosine triphosphate testing and terminal cultures: a clinical pilot study.

PubMed

Visrodia, Kavel; Hanada, Yuri; Pennington, Kelly M; Tosh, Pritish K; Topazian, Mark D; Petersen, Bret T

2017-07-01

Recent reports of infectious outbreaks linked to duodenoscopes have led to proposals for duodenoscope surveillance culturing, which has inherent limitations. We aimed to assess the feasibility of real-time adenosine triphosphate (ATP) testing after manual cleaning and its ability to predict reprocessing adequacy, as determined by terminal duodenoscope cultures. Clinically used duodenoscopes underwent reprocessing per current guidelines. After manual cleaning, ATP samples were obtained from the elevator, within the proximal biopsy port, and by flushing of the biopsy channel. After high-level disinfection (HLD), aerobic cultures of the elevator and biopsy channel were obtained using sterile technique. Duodenoscopes with any ATP sample ≥200 relative light units underwent repeated cycles of cleaning, ATP testing, HLD, and terminal culturing. Twenty clinically used duodenoscopes were included; 18 underwent a second reprocessing cycle, and 6 underwent a third reprocessing cycle because of detection of high ATP. After the initial reprocessing cycle, 12 of 20 (60%) duodenoscopes had positive culture results, most commonly yielding gram-negative bacilli (GNB, n = 11 from 9 duodenoscopes), and catalase-positive gram-positive cocci (CP-GPC, n = 7 from 7 duodenoscopes), suggesting staphylococcal organisms. Ambient environmental controls also showed GNB and CP-GPC growth. The overall sensitivity and specificity of ATP testing compared with terminal cultures were 30% and 53%, respectively. ATP sampling appears to correlate poorly with terminal culture results and cannot be recommended as a surrogate for terminal cultures. The performance and interpretation of cultures remains complicated by the potential recovery of environmental contaminants. Copyright © 2017 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

A Synthesis of Solar Cycle Prediction Techniques

NASA Technical Reports Server (NTRS)

Hathaway, David H.; Wilson, Robert M.; Reichmann, Edwin J.

1999-01-01

A number of techniques currently in use for predicting solar activity on a solar cycle timescale are tested with historical data. Some techniques, e.g., regression and curve fitting, work well as solar activity approaches maximum and provide a month-by-month description of future activity, while others, e.g., geomagnetic precursors, work well near solar minimum but only provide an estimate of the amplitude of the cycle. A synthesis of different techniques is shown to provide a more accurate and useful forecast of solar cycle activity levels. A combination of two uncorrelated geomagnetic precursor techniques provides a more accurate prediction for the amplitude of a solar activity cycle at a time well before activity minimum. This combined precursor method gives a smoothed sunspot number maximum of 154 plus or minus 21 at the 95% level of confidence for the next cycle maximum. A mathematical function dependent on the time of cycle initiation and the cycle amplitude is used to describe the level of solar activity month by month for the next cycle. As the time of cycle maximum approaches a better estimate of the cycle activity is obtained by including the fit between previous activity levels and this function. This Combined Solar Cycle Activity Forecast gives, as of January 1999, a smoothed sunspot maximum of 146 plus or minus 20 at the 95% level of confidence for the next cycle maximum.

Relationship between skin temperature and muscle activation during incremental cycle exercise.

PubMed

Priego Quesada, Jose I; Carpes, Felipe P; Bini, Rodrigo R; Salvador Palmer, Rosario; Pérez-Soriano, Pedro; Cibrián Ortiz de Anda, Rosa M

2015-02-01

While different studies showed that better fitness level adds to the efficiency of the thermoregulatory system, the relationship between muscular effort and skin temperature is still unknown. Therefore, the present study assessed the relationship between neuromuscular activation and skin temperature during cycle exercise. Ten physically active participants performed an incremental workload cycling test to exhaustion while neuromuscular activations were recorded (via surface electromyography - EMG) from rectus femoris, vastus lateralis, biceps femoris and gastrocnemius medialis. Thermographic images were recorded before, immediately after and 10 min after finishing the cycling test, at four body regions of interest corresponding to the muscles where neuromuscular activations were monitored. Frequency band analysis was conducted to assess spectral properties of EMG signals in order to infer on priority in recruitment of motor units. Significant inverse relationship between changes in skin temperature and changes in overall neuromuscular activation for vastus lateralis was observed (r<-0.5 and p<0.04). Significant positive relationship was observed between skin temperature and low frequency components of neuromuscular activation from vastus lateralis (r>0.7 and p<0.01). Participants with larger overall activation and reduced low frequency component for vastus lateralis activation presented a better adaptive response of their thermoregulatory system by showing fewer changes in skin temperature after incremental cycling test. Copyright © 2014 Elsevier Ltd. All rights reserved.

Estrous cycle and food availability affect feeding induced by amygdala 5-HT receptor blockade.

PubMed

Parker, Graham C; Bishop, Christopher; Coscina, Donald V

2002-04-01

We have recently reported that bilateral infusions of the 5-HT receptor antagonist metergoline (MET) into the posterior basolateral amygdala (pBLA) elicit feeding in female rats tested at mid-light cycle. The present study was performed to determine whether (1) testing at two different phases of the estrous cycle, and/or (2) the palatability of the food might modify this effect. Subjects were 18 adult females with bilateral pBLA cannulae. Following familiarization with Froot Loops cereal, a within-subjects design tested all animals for 1- and 2-h food intake under 2 Drug (0.3 nmol MET vs. Vehicle), 2 Estrous Cycle (diestrus vs. estrus) and 2 Food (lab chow vs. Froot Loops) conditions. Rats weighed more at diestrus than at proestrus (P<.05) or estrus (P<.005). Multivariate analyses of variance (MANOVAs) revealed a preference for Froot Loops over lab chow (P<.0001). MET increased feeding regardless of food type (P<.0001). Rats ate more Froot Loops (P<.01), but not lab chow, at diestrus vs. estrus. A three-way interaction (P<.05) showed rats ate more during the first hour in estrus than in diestrus to lab chow but not Froot Loops. These data suggest pBLA MET differentially affects feeding over the estrous cycle depending on the palatability of food available.

Empowering Older Patients to Engage in Self Care: Designing an Interactive Robotic Device

PubMed Central

Tiwari, Priyadarshi; Warren, Jim; Day, Karen

2011-01-01

Objectives: To develop and test an interactive robot mounted computing device to support medication management as an example of a complex self-care task in older adults. Method: A Grounded Theory (GT), Participatory Design (PD) approach was used within three Action Research (AR) cycles to understand design requirements and test the design configuration addressing the unique task requirements. Results: At the end of the first cycle a conceptual framework was evolved. The second cycle informed architecture and interface design. By the end of third cycle residents successfully interacted with the dialogue system and were generally satisfied with the robot. The results informed further refinement of the prototype. Conclusion: An interactive, touch screen based, robot-mounted information tool can be developed to support healthcare needs of older people. Qualitative methods such as the hybrid GT-PD-AR approach may be particularly helpful for innovating and articulating design requirements in challenging situations. PMID:22195203

Empowering older patients to engage in self care: designing an interactive robotic device.

PubMed

Tiwari, Priyadarshi; Warren, Jim; Day, Karen

2011-01-01

To develop and test an interactive robot mounted computing device to support medication management as an example of a complex self-care task in older adults. A Grounded Theory (GT), Participatory Design (PD) approach was used within three Action Research (AR) cycles to understand design requirements and test the design configuration addressing the unique task requirements. At the end of the first cycle a conceptual framework was evolved. The second cycle informed architecture and interface design. By the end of third cycle residents successfully interacted with the dialogue system and were generally satisfied with the robot. The results informed further refinement of the prototype. An interactive, touch screen based, robot-mounted information tool can be developed to support healthcare needs of older people. Qualitative methods such as the hybrid GT-PD-AR approach may be particularly helpful for innovating and articulating design requirements in challenging situations.

Solar dynamic power module design

NASA Technical Reports Server (NTRS)

Secunde, Richard R.; Labus, Thomas L.; Lovely, Ronald G.

1989-01-01

Studies have shown that use of solar dynamic (SD) power for the growth eras of the Space Station Freedom program will result in life cycle cost savings when compared to power supplied by photovoltaic sources. In the SD power module, a concentrator collects and focuses solar energy into a heat receiver which has integral thermal energy storage. A power conversion unit (PCU) based on the closed Brayton thermodynamic cycle removes thermal energy from the receiver and converts that energy to electrical energy. Since the closed Brayton cycle is a single phase gas cycle, the conversion hardware (heat exchangers, turbine, compressor, etc.) can be designed for operation in low earth orbit, and tested with confidence in test facilities on earth before launch into space. The concentrator subassemblies will be aligned and the receiver/PCU/radiator combination completely assembled and charged with gas and cooling liquid on earth before launch to, and assembly on orbit.

A Preliminary Study on Designing and Testing of an Absorption Refrigeration Cycle Powered by Exhaust Gas of Combustion Engine

NASA Astrophysics Data System (ADS)

Napitupulu, F. H.; Daulay, F. A.; Dedy, P. M.; Denis; Jecson

2017-03-01

In order to recover the waste heat from the exhaust gas of a combustion engine, an adsorption refrigeration cycle is proposed. This is a preliminary study on design and testing of a prototype of absorption refrigeration cycle powered by an internal combustion engine. The heat source of the cycle is a compression ignition engine which generates 122.36 W of heat in generator of the cycle. The pairs of absorbent and refrigerant are water and ammonia. Here the generator is made of a shell and tube heat exchanger with number of tube and its length are 20 and 0.69 m, respectively. In the experiments the exhaust gas, with a mass flow rate of 0.00016 kg/s, enters the generator at 110°C and leaves it at 72°C. Here, the solution is heated from 30°C to 90°C. In the evaporator, the lowest temperature can be reached is 17.9°C and COP of the system is 0.45. The main conclusion can be drawn here is that the proposed system can be used to recycle the waste heat and produced cooling. However, the COP is still low.

40 CFR 1065.501 - Overview.

Code of Federal Regulations, 2011 CFR

2011-07-01

... engine and sampling systems. (7) Sample emissions throughout the duty cycle. (8) Record post-test data. (9) Perform post-test procedures to verify proper operation of certain equipment and analyzers. (10... PROCEDURES Performing an Emission Test Over Specified Duty Cycles § 1065.501 Overview. (a) Use the procedures...

40 CFR 1065.501 - Overview.

Code of Federal Regulations, 2010 CFR

2010-07-01

... engine and sampling systems. (7) Sample emissions throughout the duty cycle. (8) Record post-test data. (9) Perform post-test procedures to verify proper operation of certain equipment and analyzers. (10... PROCEDURES Performing an Emission Test Over Specified Duty Cycles § 1065.501 Overview. (a) Use the procedures...

40 CFR 1065.501 - Overview.

Code of Federal Regulations, 2014 CFR

2014-07-01

... engine and sampling systems. (7) Sample emissions throughout the duty cycle. (8) Record post-test data. (9) Perform post-test procedures to verify proper operation of certain equipment and analyzers. (10... PROCEDURES Performing an Emission Test Over Specified Duty Cycles § 1065.501 Overview. (a) Use the procedures...

40 CFR 1065.501 - Overview.

Code of Federal Regulations, 2013 CFR

2013-07-01

... engine and sampling systems. (7) Sample emissions throughout the duty cycle. (8) Record post-test data. (9) Perform post-test procedures to verify proper operation of certain equipment and analyzers. (10... PROCEDURES Performing an Emission Test Over Specified Duty Cycles § 1065.501 Overview. (a) Use the procedures...

40 CFR 1065.501 - Overview.

Code of Federal Regulations, 2012 CFR

2012-07-01

... engine and sampling systems. (7) Sample emissions throughout the duty cycle. (8) Record post-test data. (9) Perform post-test procedures to verify proper operation of certain equipment and analyzers. (10... PROCEDURES Performing an Emission Test Over Specified Duty Cycles § 1065.501 Overview. (a) Use the procedures...

Correlation of Toughness between H-Plate and Charpy Impact Tests

DTIC Science & Technology

1959-09-01

thermal cycles having peak temperatures in or near the range of critical transformation temperatures. Notch sensitivity in these regions has been...21- In their recent work the transition temperatures of heat-affected-zone struc- tures produced by thermal cycles having peak temperatures in the...gradient of thermal cycles associated with welding is too complex to have been included in the scope of this report. The superior toughness of the Ni

Effect of repeated immersion solution cycles on the color stability of denture tooth acrylic resins

PubMed Central

da SILVA, Paulo Maurício Batista; ACOSTA, Emílio José Tabaré Rodríguez; JACOBINA, Matheus; PINTO, Luciana de Rezende; PORTO, Vinícius Carvalho

2011-01-01

Objective Chemical solutions have been widely used for disinfection of dentures, but their effect on color stability of denture tooth acrylic resins after repeated procedures is still unclear. The aim of this in vitro study was to evaluate whether repeated cycles of chemical disinfectants affected the color stability of two denture tooth acrylic resins. Material and Methods Sixty disc-shaped specimens (40 mm x 3 mm) were fabricated from two different brands (Artiplus and Trilux) of denture tooth acrylic resin. The specimens from each brand (n=30) were randomly divided into 6 groups (n=5) and immersed in the following solutions: distilled water (control group) and 5 disinfecting solutions (1% sodium hypochlorite, 2% sodium hypochlorite, 5.25% sodium hypochlorite, 2% glutaraldehyde, and 4% chlorhexidine gluconate). Tooth color measurements were made by spectrophotometry. Before disinfection, the initial color of each tooth was recorded. Further color measurements were determined after subjecting the specimens to 7, 21, 30, 45, 60, and 90 immersion cycles in each tested solution. Color differences (ΔE*) were determined using the CIE L*a*b* color system. Data were analyzed using two-way repeated measures analysis of variance (ANOVA) followed by Tukey tests. The significance level was set at 5%. Results There were statistically significant differences in ΔE* among the 5 disinfectants and water during the 90 cycles of immersion for both denture tooth acrylic resins. Distilled water promoted the greatest color change in both denture tooth acrylic resins, nevertheless none of tested disinfectants promoted ΔE* values higher than 1.0 on these acrylic materials during the 90 cycles of disinfection. Conclusions Repeated immersion cycles in disinfecting solutions alter ∆E* values, however these values do not compromise the color of the tested denture tooth acrylic resins because they are imperceptible to the human eye. PMID:22230997

Environmental tests of metallization systems for terrestrial photovoltaic cells

NASA Technical Reports Server (NTRS)

Alexander, P., Jr.

1985-01-01

Seven different solar cell metallization systems were subjected to temperature cycling tests and humidity tests. Temperature cycling excursions were -50 deg C to 150 deg C per cycle. Humidity conditions were 70 deg C at 98% relative humidity. The seven metallization systems were: Ti/Ag, Ti/Pd/Ag, Ti/Pd/Cu, Ni/Cu, Pd/Ni/Solder, Cr/Pd/Ag, and thick film Ag. All metallization systems showed a slight to moderate decrease in cell efficiencies after subjection to 1000 temperature cycles. Six of the seven metallization systems also evidenced slight increases in cell efficiencies after moderate numbers of cycles, generally less than 100 cycles. The copper based systems showed the largest decrease in cell efficiencies after temperature cycling. All metallization systems showed moderate to large decreases in cell efficiencies after 123 days of humidity exposure. The copper based systems again showed the largest decrease in cell efficiencies after humidity exposure. Graphs of the environmental exposures versus cell efficiencies are presented for each metallization system, as well as environmental exposures versus fill factors or series resistance.

Development of an accelerated reliability test schedule for terrestrial solar cells

NASA Technical Reports Server (NTRS)

Lathrop, J. W.; Prince, J. L.

1981-01-01

An accelerated test schedule using a minimum amount of tests and a minimum number of cells has been developed on the basis of stress test results obtained from more than 1500 cells of seven different cell types. The proposed tests, which include bias-temperature, bias-temperature-humidity, power cycle, thermal cycle, and thermal shock tests, use as little as 10 and up to 25 cells, depending on the test type.

An equation to predict the maximal lactate steady state from ramp-incremental exercise test data in cycling.

PubMed

Iannetta, Danilo; Fontana, Federico Y; Maturana, Felipe Mattioni; Inglis, Erin Calaine; Pogliaghi, Silvia; Keir, Daniel A; Murias, Juan M

2018-05-23

The maximal lactate steady state (MLSS) represents the highest exercise intensity at which an elevated blood lactate concentration ([Lac] b ) is stabilized above resting values. MLSS quantifies the boundary between the heavy-to-very-heavy intensity domains but its determination is not widely performed due to the number of trials required. This study aimed to: (i) develop a mathematical equation capable of predicting MLSS using variables measured during a single ramp-incremental cycling test and (ii) test the accuracy of the optimized mathematical equation. The predictive MLSS equation was determined by stepwise backward regression analysis of twelve independent variables measured in sixty individuals who had previously performed ramp-incremental exercise and in whom MLSS was known (MLSS obs ). Next, twenty-nine different individuals were prospectively recruited to test the accuracy of the equation. These participants performed ramp-incremental exercise to exhaustion and two-to-three 30-min constant-power output cycling bouts with [Lac] b sampled at regular intervals for determination of MLSS obs . Predicted MLSS (MLSS pred ) and MLSS obs in both phases of the study were compared by paired t-test, major-axis regression and Bland-Altman analysis. The predictor variables of MLSS were: respiratory compensation point (Wkg -1 ), peak oxygen uptake (V˙O 2peak ) (mlkg -1 min -1 ) and body mass (kg). MLSS pred was highly correlated with MLSS obs (r=0.93; p<0.01). When this equation was tested on the independent group, MLSS pred was not different from MLSS obs (234±43 vs. 234±44W; SEE 4.8W; r=0.99; p<0.01). These data support the validity of the predictive MLSS equation. We advocate its use as a time-efficient alternative to traditional MLSS testing in cycling. Copyright © 2018 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

SPECIATED VOC EMISSIONS FROM MODERN GDI LIGHT ...

EPA Pesticide Factsheets

Chassis dynamometer emissions testing was conducted to characterize speciated volatile organic compounds (VOCs), including mobile source air toxics (MSATs) and ozone precursors, in exhaust emissions from three modern gasoline direct injection (GDI) light-duty vehicles. Each GDI vehicle tested in this study utilized slightly different fuel injection technology: Vehicle 1 used a 2.4 liter, naturally aspirated, wall-guided GDI; Vehicle 2 used a 1.8 liter, turbocharged GDI engine; Vehicle 3 used a 1.5 liter, turbocharged, spray-guided GDI engine. Vehicle testing was conducted in a temperature controlled chassis dynamometer test cell at 22 °C over the EPA Federal Test Procedure (FTP) and a portion of the Supplemental FTP (SFTP). The FTP was conducted as a three phase cycle with a cold start, hot transient, and warm start phase (also known as the FTP-75 driving cycle). The SFTP consisted of the US06 driving cycle (conducted without the vehicle’s air conditioning on), which provides a more aggressive driving pattern than the FTP. The vehicles operated on 10 percent ethanol blended gasoline (E10). VOC emissions from diluted vehicle exhaust were sampled over each FTP phase and over the Supplemental FTP with SUMMA canisters for EPA Method TO-15 analysis and with DNPH cartridges for carbonyl analysis by EPA Method TO-11A. This presentation will report the impact of driving cycle and GDI technology on speciated MSAT emissions. MSAT emission rates will be compared

Comparison of real-world and certification emission rates for light duty gasoline vehicles.

PubMed

Khan, Tanzila; Frey, H Christopher

2018-05-01

U.S. light duty vehicles are subject to the U.S. Environmental Protection Agency (EPA) emission standards. Emission compliance is determined by certification testing of selected emissions from representative vehicles on standard driving cycles using chassis dynamometers. Test results are also used in many emission inventories. The dynamometer based emission rates are adjusted to provide the certification levels (CL), which must be lower than the standards for compliance. Although standard driving cycles are based on specific observations of real-world driving, they are not necessarily real-world representative. A systematic comparison of the real-world emission rates of U.S. light duty gasoline vehicles (LDGVs) versus CL, and emission standards has not been previously reported. The purpose of this work is to compare regulatory limits (both CLs and emission standards) and the real-world emissions of LDGVs. The sensitivity of the comparisons to cold start emission was assessed. Portable Emission Measurement Systems (PEMS) were used to measure hot stabilized exhaust emissions of 122 LDGVs on a specified 110 mile test route. Cold start emissions were measured with PEMS for a selected vehicle sample of 32 vehicles. Emissions were measured for carbon dioxide (CO 2 ), carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NO x ). For each vehicle, a Vehicle Specific Power (VSP) modal emission rate model was developed. The VSP modal rates were weighted by the standard driving cycles and real-world driving cycles to estimate the respective cycle average emission rates (CAERs). Measured vehicles were matched with certification test vehicles for comparison. For systematic trends in comparison, vehicles were classified into four groups based on the Tier 1 and Tier 2 emission regulation, and the vehicle type such as passenger car and passenger truck. Depending on the cycle-pollutant and the vehicle groups, hot stabilized CAERs are on average either statistically significantly higher than or significantly not different from the CLs, with the exception of CO on the US06 cycle, for which real-world rates are lower than CLs. Compared to the emission standards, hot stabilized CAERs are on average significantly lower. However, comparisons of CAERs and standards are sensitive to cold start emissions. For some combinations of pollutants and vehicle groups, cold start inclusive CAERs are higher than the corresponding CLs and as high as the standards. The CLs, which are based on standard driving cycles, tend to underestimate real-world emission rates. Therefore, emission inventory estimates using certification test results are potentially underestimated. Copyright © 2017 Elsevier B.V. All rights reserved.

Separator for lithium-sulfur battery based on polymer blend membrane

NASA Astrophysics Data System (ADS)

Freitag, Anne; Stamm, Manfred; Ionov, Leonid

2017-09-01

In this work we report a novel way of reducing the polysulfide shuttle in lithium-sulfur batteries by a new separator material. Polyvinylsulfate potassium salt (PVSK) as polymeric additive is introduced into a polyvinylidene fluoride-hexafluoropropylene (PVdF-HFP) matrix membrane to improve the battery performance. PVSK is expected to lower the polysulfide mobility due to interaction with the sulfonic group. PVdF-HFP/PVSK blend membranes are prepared and an UV/Vis polysulfide diffusion test clearly demonstrates the positive effect of PVSK. Electrochemical testing reveals a significant improvement of cycling stability up to more than 200 cycles. In addition, the effect of separator porosity to the polysulfide shuttle is investigated with PVdF-HFP membranes of different porosity. A simple polysulfide diffusion test and potentiostatic charge/discharge cycling clearly demonstrate that low separator porosity is favorable in a lithium-sulfur cell.

A driving cycle for vehicle emissions estimation in the metropolitan area of Mexico City.

PubMed

Schifter, I; Díaz, L; Rodríguez, R; López-Salinas, E

2005-02-01

A driving cycle derived from driving behavior and real traffic conditions in Mexico City (MC) is proposed. Data acquisition was carried out over diverse MC routes, representing travel under congested and uncongested conditions, using the chase-car approach. Thirteen different on-road patterns, including the four main access roads to MC, trips in both directions and different timetables, a total of 108 trips spanning 1044 km were evaluated in this study. The MC cycle lasts 1360 seconds with a distance of 8.8 km and average speed of 23.4 km h(-1). Both maximum speed (73.6 km h(-1)) and maximum acceleration (2.22 km h(-1)s(-1)) are lower than those of the new vehicles certification employed in Mexico ,FTP-75 cycle., that is, the MC cycle exhibits less cruising time and more transient events than the FTP cycle. A total of 30 light duty gasoline vehicles were classified into different technological groups and tested in an FTP-75 and MC driving cycles in order to compare their emission factors A potential concern is that in Mexico manufacturers design vehicles to meet the emission standards in the FTP, but emission levels increase significantly in a more representative cycle of present driving patterns in the Metropolitan Area of Mexico City (MAMC). The use of a more representative cycle during certification testing, would provide an incentive for vehicle manufacturers to design emissions control systems to remain effective during operation modes that are not currently represented in the official test procedures used in the certification process. Based on the results of the study, the use of MC cycle, which better represents current day driving patterns during testing of vehicle fleets in emissions laboratories, would improve the accuracy of emissions factors used in the MAMC emissions inventories.

Estimating surface temperature in forced convection nucleate boiling: A simplified method

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Papell, S. S.

1977-01-01

During a test program to investigate low-cycle thermal fatigue, 21 of 22 cylindrical test sections of a cylindrical rocket thrust chamber were thermally cycled to failure. Cylinder liners were fabricated from OFHC copper, Amzirc, and NARloy-Z. The cylinders were fabricated by milling cooling channels into the liner and closing out the backside with electrodeposited copper. The tests were conducted at a chamber pressure of 4.14 MN/sq m (600 psia) and an oxidant-fuel ratio of 6.0 using hydrogen-oxygen as propellants. The average throat heat flux was 54 MW/sq m (33 Btu/sq in./sec). All of the failures were characterized by a thinning of the cooling channel wall and eventual failure by tensile rupture. The 1/2-hard Amzirc material showed little improvement in cyclic life when compared with OFHC copper; while the NARloy-Z and aged Amzirc materials had the best cyclic life characteristics. One OFHC copper cylinder was thermall cycled 2044 times at a steady-state hot-gas-side wall temperature of 514 K (925 R) without failing.

Cell cycle re-entry sensitizes podocytes to injury induced death.

PubMed

Hagen, Manuel; Pfister, Eva; Kosel, Andrea; Shankland, Stuart; Pippin, Jeffrey; Amann, Kerstin; Daniel, Christoph

2016-07-17

Podocytes are terminally differentiated renal cells, lacking the ability to regenerate by proliferation. However, during renal injury, podocytes re-enter into the cell cycle but fail to divide. Earlier studies suggested that re-entry into cell cycle results in loss of podocytes, but a direct evidence for this is lacking. Therefore, we established an in vitro model to test the consequences of re-entry into the cell cycle on podocyte survival. A mouse immortalized podocyte cell line was differentiated to non-permissive podocytes and stimulated with e.g. growth factors. Stimulated cells were analyzed for mRNA-expression or stained for cell cycle analysis using flow cytometry and immunocytofluorescence microscopy. After stimulation to re-entry into cell cycle, podocytes were stressed with puromycin aminonucleoside (PAN) and analyzed for survival. During permissive stage more than 40% of immortalized podocytes were in the S-phase. In contrast, S-phase in non-permissive differentiated podocytes was reduced to 5%. Treatment with b-FGF dose dependently induced re-entry into cell cycle increasing the number of podocytes in the S-phase to 10.7% at an optimal bFGF dosage of 10 ng/ml. Forty eight hours after stimulation with bFGF the number of bi-nucleated podocytes significantly increased. A secondary injury stimulus significantly reduced podocyte survival preferentially in bi-nucleated podocytes In conclusion, stimulation of podocytes using bFGF was able to induce re-entry of podocytes into the cell cycle and to sensitize the cells for cell death by secondary injuries. Therefore, this model is appropriate for testing new podocyte protective substances that can be used for therapy.

The Effect of Teaching Model ‘Learning Cycles 5E’ toward Students’ Achievement in Learning Mathematic at X Years Class SMA Negeri 1 Banuhampu 2013/2014 Academic Year

NASA Astrophysics Data System (ADS)

Yeni, N.; Suryabayu, E. P.; Handayani, T.

2017-02-01

Based on the survey showed that mathematics teacher still dominated in teaching and learning process. The process of learning is centered on the teacher while the students only work based on instructions provided by the teacher without any creativity and activities that stimulate students to explore their potential. Realized the problem above the writer interested in finding the solution by applying teaching model ‘Learning Cycles 5E’. The purpose of his research is to know whether teaching model ‘Learning Cycles 5E’ is better than conventional teaching in teaching mathematic. The type of the research is quasi experiment by Randomized Control test Group Only Design. The population in this research were all X years class students. The sample is chosen randomly after doing normality, homogeneity test and average level of students’ achievement. As the sample of this research was X.7’s class as experiment class used teaching model learning cycles 5E and X.8’s class as control class used conventional teaching. The result showed us that the students achievement in the class that used teaching model ‘Learning Cycles 5E’ is better than the class which did not use the model.

The effect of advanced ultrasonic forging on fatigue fracture mechanisms of welded Ti-6A1-4V alloy

NASA Astrophysics Data System (ADS)

Smirnova, A.; Pochivalov, Yu.; Panin, V.; Panin, S.; Eremin, A.; Gorbunov, A.

2017-12-01

The current study is devoted to application of advanced postwelding ultrasonic forging to joints formed by laser welding of Ti-6A1-4V alloy in order to enhance their mechanical properties and fatigue durability. Low cycle fatigue tests were performed via digital image correlation technique used to obtain strain fields and in situ characterization of deformation, crack growth and fracture. Fracture surfaces were studied by SEM analysis accompanied with calculation of fracture patterns percentage. The fatigue tests demonstrate the high increase in the number of cycles until fracture (from 17 000 to 32 000 cycles) which could be explained by high ductility of welded material after treatment. This leads to lower fatigue crack growth rate due to higher energy dissipation. The obtained effect is attributable only for small cracks on micro-/mesoscales and fails to play a significant role for macro cracks.

Effect of Discharge Rate on Positive Active Material of Lead Carbon Battery for Energy Storage

NASA Astrophysics Data System (ADS)

Chen, Kailun; Liu, Hao; Hu, Chen; Gao, Fei; Yang, Kai; Wang, Hao

2017-10-01

Lead carbon battery has been widespread concern with its excellent performance of charge and discharge under High Rate Part State of Charge (HRPSoC) as well as its cycle performance. In this paper, the cycling performance of lead carbon battery for energy storage was tested by different discharge rate. The effects of different discharge rate on the composition and morphology of positive active materials in the cycle was studied by XRD and SEM. The effect of different discharge rate on the ohmic impedance of lead carbon battery was studied by testing Electrochemical Impedance Spectroscopy with different capacity retention rates. The results show that with the increase of the discharge rate, the content of PbO2 in the positive active material increases, the active substance utilization and the particle size of PbO2 crystal declines, and the ohmic impedance of the battery decreases.

Prediction of thermal cycling induced cracking in polmer matrix composites

NASA Technical Reports Server (NTRS)

Mcmanus, Hugh L.

1994-01-01

The work done in the period August 1993 through February 1994 on the 'Prediction of Thermal Cycling Induced Cracking In Polymer Matrix Composites' program is summarized. Most of the work performed in this period, as well as the previous one, is described in detail in the attached Master's thesis, 'Analysis of Thermally Induced Damage in Composite Space Structures,' by Cecelia Hyun Seon Park. Work on a small thermal cycling and aging chamber was concluded in this period. The chamber was extensively tested and calibrated. Temperatures can be controlled very precisely, and are very uniform in the test chamber. Based on results obtained in the previous period of this program, further experimental progressive cracking studies were carried out. The laminates tested were selected to clarify the differences between the behaviors of thick and thin ply layers, and to explore other variables such as stacking sequence and scaling effects. Most specimens tested were made available from existing stock at Langley Research Center. One laminate type had to be constructed from available prepreg material at Langley Research Center. Specimens from this laminate were cut and prepared at MIT. Thermal conditioning was carried out at Langley Research Center, and at the newly constructed MIT facility. Specimens were examined by edge inspection and by crack configuration studies, in which specimens were sanded down in order to examine the distribution of cracks within the specimens. A method for predicting matrix cracking due to decreasing temperatures and/or thermal cycling in all plies of an arbitrary laminate was implemented as a computer code. The code also predicts changes in properties due to the cracking. Extensive correlations between test results and code predictions were carried out. The computer code was documented and is ready for distribution.

Solar Thermochemical Energy Storage Through Carbonation Cycles of SrCO3/SrO Supported on SrZrO3.

PubMed

Rhodes, Nathan R; Barde, Amey; Randhir, Kelvin; Li, Like; Hahn, David W; Mei, Renwei; Klausner, James F; AuYeung, Nick

2015-11-01

Solar thermochemical energy storage has enormous potential for enabling cost-effective concentrated solar power (CSP). A thermochemical storage system based on a SrO/SrCO3 carbonation cycle offers the ability to store and release high temperature (≈1200 °C) heat. The energy density of SrCO3/SrO systems supported by zirconia-based sintering inhibitors was investigated for 15 cycles of exothermic carbonation at 1150 °C followed by decomposition at 1235 °C. A sample with 40 wt % of SrO supported by yttria-stabilized zirconia (YSZ) shows good energy storage stability at 1450 MJ m(-3) over fifteen cycles at the same cycling temperatures. After further testing over 45 cycles, a decrease in energy storage capacity to 1260 MJ m(-3) is observed during the final cycle. The decrease is due to slowing carbonation kinetics, and the original value of energy density may be obtained by lengthening the carbonation steps. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Mechanistic Thermal Fatigue Model for SnAgCu Solder Joints

NASA Astrophysics Data System (ADS)

Borgesen, Peter; Wentlent, Luke; Hamasha, Sa'd.; Khasawneh, Saif; Shirazi, Sam; Schmitz, Debora; Alghoul, Thaer; Greene, Chris; Yin, Liang

2018-02-01

The present work offers both a complete, quantitative model and a conservative acceleration factor expression for the life span of SnAgCu solder joints in thermal cycling. A broad range of thermal cycling experiments, conducted over many years, has revealed a series of systematic trends that are not compatible with common damage functions or constitutive relations. Complementary mechanical testing and systematic studies of the evolution of the microstructure and damage have led to a fundamental understanding of the progression of thermal fatigue and failure. A special experiment was developed to allow the effective deconstruction of conventional thermal cycling experiments and the finalization of our model. According to this model, the evolution of damage and failure in thermal cycling is controlled by a continuous recrystallization process which is dominated by the coalescence and rotation of dislocation cell structures continuously added to during the high-temperature dwell. The dominance of this dynamic recrystallization contribution is not consistent with the common assumption of a correlation between the number of cycles to failure and the total work done on the solder joint in question in each cycle. It is, however, consistent with an apparent dependence on the work done during the high-temperature dwell. Importantly, the onset of this recrystallization is delayed by pinning on the Ag3Sn precipitates until these have coarsened sufficiently, leading to a model with two terms where one tends to dominate in service and the other in accelerated thermal cycling tests. Accumulation of damage under realistic service conditions with varying dwell temperatures and times is also addressed.

Does the New European Driving Cycle (NEDC) really fail to capture the NOX emissions of diesel cars in Europe?

PubMed

Degraeuwe, Bart; Weiss, Martin

2017-03-01

Tests with Portable Emissions Measurement Systems (PEMS) have demonstrated that diesel cars emit several times more NO X on the road than during certification on the New European Driving Cycle (NEDC). Policy makers and scientists have attributed the discrepancy to the unrealistically low dynamics and the narrow temperature range of NEDC testing. Although widely accepted, this assumption was never been put under scientific scrutiny. Here, we demonstrate that the narrow NEDC test conditions explain only a small part of the elevated on-road NO X emissions of diesel cars. For seven Euro 4-6 diesel cars, we filter from on-road driving those events that match the NEDC conditions in instantaneous speed, acceleration, CO 2 emissions, and ambient temperature. The resulting on-road NO X emissions exceed by 206% (median) those measured on the NEDC, whereas the NO X emissions of all unfiltered on-road measurements exceed the NEDC emissions by 266% (median). Moreover, when applying the same filtering of on-road data to two other driving cycles (WLTP and CADC), the resulting on-road NO X emissions exceed by only 13% (median) those measured over the respective cycles. This result demonstrates that our filtering method is accurate and robust. If neither the low dynamics nor the limited temperature range of NEDC testing can explain the elevated NO X emissions of diesel cars, emissions control strategies used during NEDC testing must be inactive or modulated on the road, even if vehicles are driven under certification-like conditions. This points to defeat strategies that warrant further investigations by type-approval authorities and, in turn, limitations in the enforcement of the European vehicle emissions legislation by EU Member States. We suggest applying our method as a simple yet effective tool to screen and select vehicles for in-depth analysis by the competent certification authorities. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Mid-cycle headaches and their relationship to different patterns of premenstrual stress symptoms.

PubMed

Kiesner, Jeff; Martin, Vincent T

2013-06-01

Recent research has shown that affective changes associated with the menstrual cycle may follow diverse patterns, including a classic premenstrual syndrome pattern, as well as the mirror opposite pattern, referred to as a mid-cycle pattern. Test for the presence of a mid-cycle pattern of headaches, in addition to a menstrual pattern and a noncyclic pattern; test for an association between experiencing a specific pattern of headaches and a specific (previously identified) pattern of depression/anxiety; and test for mean-level differences, across headache pattern groups, in average headache index and depression/anxiety scores (averaged across 2 menstrual cycles for each participant). A sample of 213 female university students completed daily questionnaires regarding symptoms of headaches and depression/anxiety for 2 menstrual cycles. Hierarchical linear modeling, polynomial multiple regression, analyses of variance, and chi-square analyses were used to test the hypotheses. Confirmed the existence of a mid-cycle pattern of headaches (16%), in addition to a menstrual pattern (51%), and a noncyclic pattern of headaches (33%). Patterns of headaches and affective change were significantly associated (χ(2) = 21.33, P = .0003; 54% correspondence), as were the average headache index and depression/anxiety scores (r = .49; P < .0001). No significant mean-level differences were found between the headache pattern groups on the average headache index scores or depression/anxiety scores. A significant number of women experience a mid-cycle pattern of headaches during the menstrual cycle. Moreover, women often, but not always, demonstrate the same pattern of headaches and depression/anxiety symptoms. © 2013 American Headache Society.

Heavy-Duty Vehicle Port Drayage Drive Cycle Characterization and Development

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

Prohaska, Robert; Konan, Arnaud; Kelly, Kenneth

In an effort to better understand the operational requirements of port drayage vehicles and their potential for adoption of advanced technologies, National Renewable Energy Laboratory (NREL) researchers collected over 36,000 miles of in-use duty cycle data from 30 Class 8 drayage trucks operating at the Port of Long Beach and Port of Los Angeles in Southern California. These data include 1-Hz global positioning system location and SAE J1939 high-speed controller area network information. Researchers processed the data through NREL's Drive-Cycle Rapid Investigation, Visualization, and Evaluation tool to examine vehicle kinematic and dynamic patterns across the spectrum of operations. Using themore » k-medoids clustering method, a repeatable and quantitative process for multi-mode drive cycle segmentation, the analysis led to the creation of multiple drive cycles representing four distinct modes of operation that can be used independently or in combination. These drive cycles are statistically representative of real-world operation of port drayage vehicles. When combined with modeling and simulation tools, these representative test cycles allow advanced vehicle or systems developers to efficiently and accurately evaluate vehicle technology performance requirements to reduce cost and development time while ultimately leading to the commercialization of advanced technologies that meet the performance requirements of the port drayage vocation. The drive cycles, which are suitable for chassis dynamometer testing, were compared to several existing test cycles. This paper presents the clustering methodology, accompanying results of the port drayage duty cycle analysis and custom drive cycle creation.« less

Heavy-Duty Vehicle Port Drayage Drive Cycle Characterization and Development: Preprint

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

Prohaska, Robert; Konan, Arnaud; Kelly, Kenneth

In an effort to better understand the operational requirements of port drayage vehicles and their potential for adoption of advanced technologies, National Renewable Energy Laboratory (NREL) researchers collected over 36,000 miles of in-use duty cycle data from 30 Class 8 drayage trucks operating at the Port of Long Beach and Port of Los Angeles in Southern California. These data include 1-Hz global positioning system location and SAE J1939 high-speed controller area network information. Researchers processed the data through NREL's Drive-Cycle Rapid Investigation, Visualization, and Evaluation tool to examine vehicle kinematic and dynamic patterns across the spectrum of operations. Using themore » k-medoids clustering method, a repeatable and quantitative process for multi-mode drive cycle segmentation, the analysis led to the creation of multiple drive cycles representing four distinct modes of operation that can be used independently or in combination. These drive cycles are statistically representative of real-world operation of port drayage vehicles. When combined with modeling and simulation tools, these representative test cycles allow advanced vehicle or systems developers to efficiently and accurately evaluate vehicle technology performance requirements to reduce cost and development time while ultimately leading to the commercialization of advanced technologies that meet the performance requirements of the port drayage vocation. The drive cycles, which are suitable for chassis dynamometer testing, were compared to several existing test cycles. This paper presents the clustering methodology, accompanying results of the port drayage duty cycle analysis and custom drive cycle creation.« less

Heavy-Duty Vehicle Port Drayage Drive Cycle Characterization and Development

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

Prohaska, Robert; Konan, Arnaud; Kelly, Kenneth

2016-05-02

In an effort to better understand the operational requirements of port drayage vehicles and their potential for adoption of advanced technologies, National Renewable Energy Laboratory (NREL) researchers collected over 36,000 miles of in-use duty cycle data from 30 Class 8 drayage trucks operating at the Port of Long Beach and Port of Los Angeles in Southern California. These data include 1-Hz global positioning system location and SAE J1939 high-speed controller area network information. Researchers processed the data through NREL's Drive-Cycle Rapid Investigation, Visualization, and Evaluation tool to examine vehicle kinematic and dynamic patterns across the spectrum of operations. Using themore » k-medoids clustering method, a repeatable and quantitative process for multi-mode drive cycle segmentation, the analysis led to the creation of multiple drive cycles representing four distinct modes of operation that can be used independently or in combination. These drive cycles are statistically representative of real-world operation of port drayage vehicles. When combined with modeling and simulation tools, these representative test cycles allow advanced vehicle or systems developers to efficiently and accurately evaluate vehicle technology performance requirements to reduce cost and development time while ultimately leading to the commercialization of advanced technologies that meet the performance requirements of the port drayage vocation. The drive cycles, which are suitable for chassis dynamometer testing, were compared to several existing test cycles. This paper presents the clustering methodology, accompanying results of the port drayage duty cycle analysis and custom drive cycle creation.« less

Testing of a heat pump clothes dryer. Final report

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

McFadden, D.; Dieckmann, J.; Mallory, D.

1995-05-01

The integration of a heat pump heat source into a clothes dryer has been investigated by several U.S. and foreign appliance developers and manufacturers but no commercial or residential heat pump clothes dryers are currently available in North America. The objectives of this effort were to: (1) Evaluate a heat pump dryer prototype relative to residential dryer performance tests. (2) Quantify the product limitations. (3) Suggest design changes that would reduce the impact of the limitations or that have a positive impact on the benefits. (4) Position the product relative to utility DSM/IRP opportunities (e.g., reduced connected load, or energymore » conservation). (5) Develop preliminary cost data The program evaluated the performance of a prototype closed-cycle heat pump clothes dryer designed and built by the Nyle Corporation. The prototype design goals were: (1) Drying times equivalent to a conventional electric clothes dryer. (2) 60% reduction in energy consumption. (3) Effective lint removal (to prevent coil fouling). (4) Cool-down mode performance similar to conventional dryer. (5) 20 lb load capacity. (6) Low temperature dry for reduced clothes wrinkle. Test results indicated that the closed-cycle heat pump met some of the above mentioned goals but it fell short with respect to energy savings and dry time. Performance improvement recommendations were developed for the closed-cycle dryer approach. In addition, the closed-cycle design potential was compared to an open-cycle heat pump dryer configuration.« less

Improved Statistical Methods Enable Greater Sensitivity in Rhythm Detection for Genome-Wide Data

PubMed Central

Hutchison, Alan L.; Maienschein-Cline, Mark; Chiang, Andrew H.; Tabei, S. M. Ali; Gudjonson, Herman; Bahroos, Neil; Allada, Ravi; Dinner, Aaron R.

2015-01-01

Robust methods for identifying patterns of expression in genome-wide data are important for generating hypotheses regarding gene function. To this end, several analytic methods have been developed for detecting periodic patterns. We improve one such method, JTK_CYCLE, by explicitly calculating the null distribution such that it accounts for multiple hypothesis testing and by including non-sinusoidal reference waveforms. We term this method empirical JTK_CYCLE with asymmetry search, and we compare its performance to JTK_CYCLE with Bonferroni and Benjamini-Hochberg multiple hypothesis testing correction, as well as to five other methods: cyclohedron test, address reduction, stable persistence, ANOVA, and F24. We find that ANOVA, F24, and JTK_CYCLE consistently outperform the other three methods when data are limited and noisy; empirical JTK_CYCLE with asymmetry search gives the greatest sensitivity while controlling for the false discovery rate. Our analysis also provides insight into experimental design and we find that, for a fixed number of samples, better sensitivity and specificity are achieved with higher numbers of replicates than with higher sampling density. Application of the methods to detecting circadian rhythms in a metadataset of microarrays that quantify time-dependent gene expression in whole heads of Drosophila melanogaster reveals annotations that are enriched among genes with highly asymmetric waveforms. These include a wide range of oxidation reduction and metabolic genes, as well as genes with transcripts that have multiple splice forms. PMID:25793520