Science.gov

Sample records for temperature cycle tests

  1. A rapid-temperature-cycling apparatus for oxidation testing

    SciTech Connect

    Cabrera, A.L.; Kirner, J.F. )

    1991-06-01

    An oxidation test with rapid temperature cycling was developed to evaluate small coated parts. The samples in the form of wire or foils are resistively heated with a high-current AC power supply, allowing fast heating and cooling of the samples. Fast temperature cycling of the samples permits to complete more than 100 cycles in one day. A variety of steels coated with silicon diffusion coatings were tested and the results compared with oxidation via traditional thermal cycling. The test accurately predicts enhanced performance for siliconized 1010 steel, an increase by a factor of three for the life of siliconized 302 stainless steel, and an inadequate siliconized coating for 410 stainless steel. Details of the rapid temperature cycling apparatus as well as testing of the coated steels are described in the paper.

  2. 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.

  3. Fixture tests bellows reliability through repetitive pressure/temperature cycling

    NASA Technical Reports Server (NTRS)

    Levinson, C.

    1967-01-01

    Fixture explores the reliability of bellows used in precision in inertial systems. The fixture establishes the ability of the bellows to withstand repetitive over-stress pressure cycling at elevated temperatures. It is applicable in quality control and reliability programs.

  4. 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.

  5. Long-term storage life of light source modules by temperature cycling accelerated life test

    NASA Astrophysics Data System (ADS)

    Ningning, Sun; Manqing, Tan; Ping, Li; Jian, Jiao; Xiaofeng, Guo; Wentao, Guo

    2014-05-01

    Light source modules are the most crucial and fragile devices that affect the life and reliability of the interferometric fiber optic gyroscope (IFOG). While the light emitting chips were stable in most cases, the module packaging proved to be less satisfactory. In long-term storage or the working environment, the ambient temperature changes constantly and thus the packaging and coupling performance of light source modules are more likely to degrade slowly due to different materials with different coefficients of thermal expansion in the bonding interface. A constant temperature accelerated life test cannot evaluate the impact of temperature variation on the performance of a module package, so the temperature cycling accelerated life test was studied. The main failure mechanism affecting light source modules is package failure due to solder fatigue failure including a fiber coupling shift, loss of cooling efficiency and thermal resistor degradation, so the Norris-Landzberg model was used to model solder fatigue life and determine the activation energy related to solder fatigue failure mechanism. By analyzing the test data, activation energy was determined and then the mean life of light source modules in different storage environments with a continuously changing temperature was simulated, which has provided direct reference data for the storage life prediction of IFOG.

  6. Cycling Performance of a Columnar-Structured Complex Perovskite in a Temperature Gradient Test

    NASA Astrophysics Data System (ADS)

    Schlegel, N.; Sebold, D.; Sohn, Y. J.; Mauer, G.; Vaßen, R.

    2015-10-01

    To increase the efficiency of turbines for the power generation and the aircraft industry, advanced thermal barrier coatings (TBCs) are required. They need to be long-term stable at temperatures higher than 1200 °C. Nowadays, yttria partially stabilized zirconia (YSZ) is applied as standard TBC material. But its long-term application at temperatures higher than 1200 °C leads to detrimental phase changes and sintering effects. Therefore, new materials have to be investigated, for example, complex perovskites. They provide high melting points, high thermal expansion coefficients and thermal conductivities of approx. 2.0 W/(m K). In this work, the complex perovskite La(Al1/4Mg1/2Ta1/4)O3 (LAMT) was investigated. It was deposited by the suspension plasma spraying (SPS) process, resulting in a columnar microstructure of the coating. The coatings were tested in thermal cycling gradient tests and they show excellent results, even though some phase decomposition was found.

  7. Long term testing of start-stop cycles on high temperature PEM fuel cell stack

    NASA Astrophysics Data System (ADS)

    Kannan, Arvind; Kabza, Alexander; Scholta, Joachim

    2015-03-01

    A PEM fuel cell with an operating temperature above 100 °C is desired for increasing the kinetics of reactions, reduced sensitivity to impurities of the fuel, as well as for the reduction of the requirements on thermal and water management systems. High Temperature Polymer Electrolyte Membrane Fuel Cells (HT-PEMFC) can effectively be combined with CHP systems to offer a simple system design and higher overall system efficiencies. For HT-PEMFC systems, the development of elaborated start/stop strategies is essential in mitigation of fuel cell degradation during these events. A 5 cell co-flow stack is assembled with BASF P1100W membrane electrode assembly (MEA) with an active area of 163.5 cm2. Continuous operation and more than 1500 start stop cycles have been performed in order to study the degradation effects of both continuous operation and of repeated start stops using a protective start-stop algorithm, which is designed to avoid the formation of aggressive cell potentials. The repeated use of this procedure led to a degradation of 26 μV/cycle at a current density of 0.25 A cm-2 and 11 μV/cycle at a current density of 0.03 A cm-2. At open circuit voltage (OCV), a higher degradation rate of 133 μV/cycle was observed.

  8. Closed cycle cryocooler for low temperature electronics circuits: Cold end test

    NASA Astrophysics Data System (ADS)

    Pirtle, F. W.

    1983-08-01

    A fabricated MACOR cold end including a metallic coating to prevent helium permeation and a fabricated die post displacer support bearing were combined with a compressor and motor which are standard CTI-CRYOGENICS products. A mechanical test was performed on the test cryocooler to determine that the mechanical test was performed on the test cryocooler to determine that the MACOR displacer was successfully guided by the die post bearing. Thermodynamic tests were conducted to determine the lowest temperature of the 4th (coldest) stage as a function of operating speed, helium charge pressure, 4th stage electrical heat load, and transfer tube diameter. Cooldown and steady state results are reported. Results indicate a low temperature limit of approximately 95K with the current test hardware. Although this represents an improvement from 122K during the program, a resizing will be necessary to reach 10K. The die post displacer support bearing and the MACOR cold finger construction are mechanically satisfactory.

  9. Current activities in standardization of high-temperature, low-cycle-fatigue testing techniques in the United States

    NASA Technical Reports Server (NTRS)

    Verrilli, Michael J.; Ellis, J. Rodney; Swindeman, Robert W.

    1990-01-01

    The American Society for Testing and Materials (ASTM) standard E606-80 is the most often used recommended testing practice for low-cycle-fatigue (LCF) testing in the United States. The standard was first adopted in 1977 for LCF testing at room temperature and was modified in 1980 to include high-temperature testing practices. Current activity within ASTM is aimed at extending the E606-80 recommended practices to LCF under thermomechanical conditions, LCF in high-pressure hydrogen, and LCF in metal-matrix composite materials. Interlaboratory testing programs conducted to generate a technical base for modifying E606-80 for the aforementioned LCF test types are discussed.

  10. 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.

  11. Effects of test design and temperature in a partial life-cycle study with the freshwater gastropod Potamopyrgus antipodarum.

    PubMed

    Macken, Ailbhe; Le Page, Gareth; Hayfield, Amanda; Williams, Timothy D; Brown, Rebecca J

    2012-09-01

    Potamopyrgus antipodarum is a candidate for a standardized mollusk partial life-cycle study. This is a comparative study of two test designs (microplate and beaker), with additional endpoints to the proposed guideline methods, for example, tracking of continuous reproductive output over 28 d and attributing it to individual female snails. In addition, an investigation of the effects of temperature (16, 20, and 25°C) on reproduction was also conducted employing the microplate design. PMID:22573501

  12. Low Temperature Life-Cycle Testing of a Lithium-Ion Battery for Low-Earth-Orbiting Spacecraft

    NASA Technical Reports Server (NTRS)

    Reid, Concha

    2006-01-01

    A flight-qualified, lithium-ion (Li-ion) battery developed for the Mars Surveyor Program 2001 Landeris 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 high specific energy, high 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 missions.

  13. Temperature and the cell cycle.

    PubMed

    Francis, D; Barlow, P W

    1988-01-01

    During the period between successive divisions, a cell traverses three stages of interphase: G1 (pre-synthetic interphase), S-phase (DNA synthetic interphase) and G2 (post-synthetic interphase). The time taken for all cells in a meristem to divide (the cell doubling time (cdt] decreases in response to an increase in temperature. For example, the cdt in root meristems of Zea mays decreases 21-fold as the temperature is increased from 3 to 25 degrees C. Whether all phases of the cell cycle alter proportionately with temperature has been ascertained by comparing data from the root meristem of five species: Pisum sativum, Helianthus annuus, Tradescantia paludosa, Allium cepa and Triticum aestivum. In three of the five species there is a disproportionate lengthening of the G1 phase at low temperatures. We suggest that arrest in G1 with the associated 2C amount of DNA, confers maximal protection on the genome of a somatic cell to the stress of low temperature. DNA replication has been studied at different temperatures for Helianthus annuus, Secale cereal and Oryza sativa. The rate of DNA replication, per single replication fork, increases when the temperature is raised, while the distance between initiation points (replicon size) remains constant. The temperature at which the cell cycle has a minimum duration is close to 30 degrees C in many species, and it seems that this optimum temperature is always near the upper temperature limit of the cell cycle. The rate of cell division determines the rates of organ and cell growth. Thus, temperature has a major effect on the way in which meristematic cells are deployed in organogenesis. The rate of organogenesis, in turn, determines the response of the plant to the growing season. We predict that species growing in sub-arctic conditions comprise cells with low DNA contents and hence have the potentialities for rapid cell cycles so that maximum advantage can be taken of a short growing season. Data from Triticum aestivum show

  14. High-temperature, high-pressure testing of zinc titanate in a bench-scale fluidized-bed reactor for 100 cycles

    SciTech Connect

    Gupta, R.P.; Gangwal, S.K.

    1993-06-01

    Integrated gasification combined cycle (IGCC) power plants are being advanced worldwide to produce electricity from coal owing to their potential for superior environmental performance, economics, and efficiency in comparison to conventional coal-based power plants. A key component of these plants is a hot-gas desulfurization system employing efficient regenerable mixed-metal oxide sorbents. Leading sorbent candidates include zinc ferrite and zinc titanate. These sorbents can remove hydrogen sulfide (H{sub 2}S) in the fuel gas down to very low levels (typically <20 ppmv) at 500 to 750{degree}C and can be readily regenerated for multicycle operation with air. To this end, the Research Triangle Institute (RTI) has formulated and tested a series of zinc titanate sorbents in a high-temperature, high- pressure HTHP fluidized-bed bench-scale reactor. Multicycle HTHP bench-scale testing of these sorbents under a variety of conditions culminated in the development of a ZT-4 sorbent that exhibited the best overall performance in terms of chemical reactivity, sulfur capacity, regenerability, structural properties, and attrition resistance. Following this parametric study, a life-cycle test consisting of 100 sulfidation-regeneration cycles was carried out with ZT-4 in the bench unit.

  15. Optical Fiber Distributed Sensing Structural Health Monitoring (SHM) Strain Measurements Taken During Cryotank Y-Joint Test Article Load Cycling at Liquid Helium Temperatures

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G.; Prosser, William H.; Hare, David A.; Moore, Thomas C.; Kenner, Winfred S.

    2007-01-01

    This paper outlines cryogenic Y-joint testing at Langley Research Center (LaRC) to validate the performance of optical fiber Bragg grating strain sensors for measuring strain at liquid helium temperature (-240 C). This testing also verified survivability of fiber sensors after experiencing 10 thermal cool-down, warm-up cycles and 400 limit load cycles. Graphite composite skins bonded to a honeycomb substrate in a sandwich configuration comprised the Y-joint specimens. To enable SHM of composite cryotanks for consideration to future spacecraft, a light-weight, durable monitoring technology is needed. The fiber optic distributed Bragg grating strain sensing system developed at LaRC is a viable substitute for conventional strain gauges which are not practical for SHM. This distributed sensing technology uses an Optical Frequency Domain Reflectometer (OFDR). This measurement approach has the advantage that it can measure hundreds of Bragg grating sensors per fiber and the sensors are all written at one frequency, greatly simplifying fiber manufacturing. Fiber optic strain measurements compared well to conventional strain gauge measurements obtained during these tests. These results demonstrated a high potential for a successful implementation of a SHM system incorporating LaRC's fiber optic sensing system on the composite cryotank and other future cryogenic applications.

  16. Optical fiber distributed sensing structural health monitoring (SHM) strain measurements taken during cryotank Y-joint test article load cycling at liquid helium temperatures

    NASA Astrophysics Data System (ADS)

    Allison, Sidney G.; Prosser, William H.; Hare, David A.; Moore, Thomas C.; Kenner, W. S.

    2007-09-01

    This paper outlines cryogenic Y-joint testing at Langley Research Center (LaRC) to validate the performance of optical fiber Bragg grating strain sensors for measuring strain at liquid helium temperature (-240°C). This testing also verified survivability of fiber sensors after experiencing 10 thermal cool-down, warm-up cycles and 400 limit load cycles. Graphite composite skins bonded to a honeycomb substrate in a sandwich configuration comprised the Y-joint specimens. To enable SHM of composite cryotanks for consideration to future spacecraft, a light-weight, durable monitoring technology is needed. The fiber optic distributed Bragg grating strain sensing system developed at LaRC is a viable substitute for conventional strain gauges which are not practical for SHM. This distributed sensing technology uses an Optical Frequency Domain Reflectometer (OFDR). This measurement approach has the advantage that it can measure hundreds of Bragg grating sensors per fiber and the sensors are all written at one frequency, greatly simplifying fiber manufacturing. Fiber optic strain measurements compared well to conventional strain gauge measurements obtained during these tests. These results demonstrated a high potential for a successful implementation of a SHM system incorporating LaRC's fiber optic sensing system on the composite cryotank and other future cryogenic applications.

  17. High-Temperature, Low-Cycle Fatigue of Copper-Base Alloys for Rocket Nozzles. Part 1: Data Summary for Materials Tested in Prior Programs

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

    A more detailed analysis of the results obtained in 188 previously reported low-cycle fatigue tests of various candidate materials for regeneratively-cooled, reusable rocket nozzle liners was reported. Plots of load range versus cycles were reported for each test along with a stress-strain hysteresis loop near half-life. In addition, a summary table was provided to compare N5 (cycles to a five percent load range drop) and Nf (cycles to complete specimen separation) values for each test.

  18. Influence of moderate cycling on scrotal temperature.

    PubMed

    Jung, A; Strauss, P; Lindner, H J; Schuppe, H C

    2008-08-01

    Testicular temperature highly correlates with scrotal temperature. It has been postulated that cycling is associated with increased scrotal temperatures with time and consecutively with impaired semen quality. The aim of this study was to evaluate the influence of moderate cycling on scrotal temperature during highly standardized conditions in an experimental lab. A total of 25 volunteers without a history of infertility and normal andrological examination were included for scrotal temperature evaluation. Scrotal temperatures were measured every minute with a portable data recorder connected with two thermistor temperature sensors, which were attached on either side of the scrotum. A further thermistor sensor was attached on the central surface of the bicycle saddle. Ambient temperature in the study room was adjusted to 22 degrees C throughout the whole experiment. All volunteers started the experiment at the same daytime. Clothing of the volunteers consisted of standardized cotton wool trousers and shirts fitting to body size. After acclimatization to the study room in a sitting posture, each volunteer cycled on an exercise cycle for 60 min with a power of 25 Watt representing a speed of 25.45 km/h respectively. The saddle surface temperature reached in the median 35.59 degrees C after 60 min cycling. Median values of scrotal temperatures increased from 35.75 degrees C at the beginning to 35.82 degrees C after 60 min for the left side and from 35.50 to 35.59 degrees C for the right side. No correlation between cycling duration and scrotal temperatures could be found using multivariate anova for repeated measurements. However, scrotal temperatures during cycling were significantly lower (p < 0.001) compared with the last 10 min in sitting posture before starting cycling with a difference of 1.31 degrees C for the left and 1.46 degrees C for the right side. The present study suggests that moderate cycling under standardized conditions with a power of 25 Watt is not

  19. Cycle life test of secondary spacecraft cells

    NASA Astrophysics Data System (ADS)

    Harkness, J. D.

    1980-04-01

    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.

  20. 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.

  1. Life cycle test of the NOXSO process

    SciTech Connect

    Ma, W.T.; Haslbeck, J.L.; Neal, L.G.

    1990-05-01

    This paper summarizes the data generated by the NOXSO Life Cycle Test Unit (LCTU). The NOXSO process is a dry flue gas treatment system that employs a reusable sorbent. The sorbent consists of sodium carbonate impregnated on a high-surface-area gamma alumina. A fluidized bed of sorbent simultaneously removes SO{sub 2} and NO{sub x} from flue gas at a temperature of 250{degrees}F. The spent sorbent is regenerated for reuse by treatment at high temperature with a reducing gas. This regeneration reduces sorbed sulfur compounds to SO{sub 2}, H{sub 2}S, and elemental sulfur. The SO{sub 2} and H{sub 2}S are then converted to elemental sulfur in a Claus-type reactor. The sulfur produced is a marketable by-product of the process. Absorbed nitrogen oxides are decomposed and evolved on heating the sorbent to regeneration temperature.

  2. PSOC cycle testing method for lithium-ion secondary batteries

    NASA Astrophysics Data System (ADS)

    Kato, Ken; Negishi, Akira; Nozaki, Ken; Tsuda, Izumi; Takano, Kiyonami

    A cycle testing procedure is proposed which carries out charge and discharge in a partial state of charge (PSOC) with some testing levels such as an averaged state of charge, temperature, etc. The PSOC cycle test with this procedure was carried out for a commercial lithium-ion cell for about 20,000 cycles, and the testing procedure and test results are discussed. The features of the degradation due to PSOC cycle test in the tested lithium-ion cell were clarified as follows. The degradation during the PSOC cycle test was greater at higher environmental temperature. The degradation was greatest at a high average SOC, and smallest at SOC=50%. The degradation increased again at a low average SOC. In the test results for 2 years with 20,000 PSOC cycles, which converted to 2200 cycles of full-capacity charge and discharge, capacity degradation was 32% even at the greatest degradation at 318 K and 8% or less at 278 K. The proposed testing procedure is useful for evaluating a cell used on partial charge and discharge cycles.

  3. A combined cycle engine test facility

    NASA Astrophysics Data System (ADS)

    Engers, R.; Cresci, D.; Tsai, C.

    Rocket-Based Combined-Cycle (RBCC) engines intended for missiles and/or space launch applications incorporate features of rocket propulsion systems operating in concert with airbreathing engine cycles. Performance evaluation of these types of engines, which are intended to operate from static sea level take-off to supersonic cruise or accerlerate to orbit, requires ground test capabilities which integrate rocket component testing with airbreathing engine testing. A combined cycle engine test facility has been constructed in the General Applied Science Laboratories, Inc. (GASL) Aeropropulsion Test Laboratory to meet this requirement. The facility was designed to support the development of an innovative combined cycle engine concept which features a rocket based ramjet combustor. The test requirements included the ability to conduct tests in which the propulsive force was generated by rocket only, the ramjet only and simultaneous rocket and ramjet power (combined cycle) to evaluate combustor operation over the entire engine cycle. The test facility provides simulation over the flight Mach number range of 0 to 8 and at various trajectories. The capabilities of the combined cycle engine test facility are presented.

  4. A combined cycle engine test facility

    SciTech Connect

    Engers, R.; Cresci, D.; Tsai, C.

    1995-09-01

    Rocket-Based Combined-Cycle (RBCC) engines intended for missiles and/or space launch applications incorporate features of rocket propulsion systems operating in concert with airbreathing engine cycles. Performance evaluation of these types of engines, which are intended to operate from static sea level take-off to supersonic cruise or accerlerate to orbit, requires ground test capabilities which integrate rocket component testing with airbreathing engine testing. A combined cycle engine test facility has been constructed in the General Applied Science Laboratories, Inc. (GASL) Aeropropulsion Test Laboratory to meet this requirement. The facility was designed to support the development of an innovative combined cycle engine concept which features a rocket based ramjet combustor. The test requirements included the ability to conduct tests in which the propulsive force was generated by rocket only, the ramjet only and simultaneous rocket and ramjet power (combined cycle) to evaluate combustor operation over the entire engine cycle. The test facility provides simulation over the flight Mach number range of 0 to 8 and at various trajectories. The capabilities of the combined cycle engine test facility are presented.

  5. Test-vehicle cycle programmer

    NASA Technical Reports Server (NTRS)

    Lesco, D. J.; Soltis, R. F.

    1978-01-01

    Instrument reduces manpower needed for testing electric powered vehicles. Device has dual scale that allows operator to compare actual speed with preprogrammed test speed. Features include large meter, buzzer, packaging to allow ready interchange of memories with different profiles, small size, minimal current drain, and reverse supply voltage protection.

  6. Testing of a Stirling cycle cooler

    SciTech Connect

    Chen, F.C.; Keshock, E.G.; Murphy, R.W.

    1988-09-01

    Stirling cycle coolers have long been used as low temperature refrigeration devices. They are relatively compact, reliable, commercially available, and use helium as the working fluid. The Stirling cycle, in principle, can be used for household refrigeration and heat pumping applications as well. Currently, these applications are almost entirely provided by the vapor compression technology using chlorofluorocarbons (CFCs) as working fluids. It has been known that CFCs cause depletion of the ozone layer that protects the earth against harmful levels of ultraviolet radiation from the sun. A recent report of a ''hole'' in the ozone layer above Antarctica and of possible environmental and health consequences from ozone depletion aroused public attention. The urgent need to reduce the future used of CFCs should instigate investigation of non-CFC alternative technologies. The Stirling cooler technology, which does not use CFCs, could be a viable alternative. A laboratory test of the performance of a Stirling cooler is reported and its implications for household refrigeration are explored. 11 refs., 6 figs., 2 tabs.

  7. Ni-MH storage test and cycle life test

    NASA Technical Reports Server (NTRS)

    Dell, R. Dan; Klein, Glenn C.; Schmidt, David F.

    1994-01-01

    Gates Aerospace Batteries is conducting two long term test programs to fully characterize the NiMH cell technology for aerospace applications. The first program analyzes the effects of long term storage upon cell performance. The second program analyzes cycle life testing and preliminary production lot testing. This paper summarizes these approaches to testing the NiMH couple and culminates with initial storage and testing recommendations. Long term storage presents challenges to deter the adverse condition of capacity fade in NiMH cells. Elevated but stabilized pressures and elevated but stabilized end-of-charge voltages also appear to be a characteristic phenomenon of long term storage modes. However, the performance degradation is dependent upon specific characteristics of the metal-hydride alloy. To date, there is no objective evidence with which to recommend the proper method for storage and handling of NiMH cells upon shipment. This is particularly critical due to limited data points that indicate open circuit storage at room temperature for 60 to 90 days will result in irrecoverable capacity loss. Accordingly a test plan was developed to determine what method of mid-term to long-term storage will prevent irrecoverable capacity loss. The explicit assumption is that trickle charging at some rate above the self-discharge rate will prevent the irreversible chemical changes to the negative electrode that result in the irrecoverable capacity loss. Another premise is that lower storage temperatures, typically 0 C for aerospace customers, will impede any negative chemical reactions. Three different trickle charge rates are expected to yield a fairly flat response with respect to recoverable capacity versus baseline cells in two different modes of open circuit. Specific attributes monitored include: end-of-charge voltage, end-of-charge pressure, mid-point discharge voltage, capacity, and end-of-discharge pressure. Cycle life testing and preliminary production lot

  8. Plasma-Catalysis During Temperature Transient Testing

    SciTech Connect

    Hoard, John

    2001-08-05

    A combination of catalysts is used together with nonthermal plasma in simulated diesel exhaust, while the gas temperature is varied. The catalysts both store and convert pollutants. As a result, pollutant concentrations during temperature ramps are different than those at steady state conditions. The data are presented for plasma followed by BaY, alumina, and Pt catalysts in simulated exhaust. When temperature ramps from high to low, apparent NOx conversion is quite high. However, when temperature is ramped from low to high, lower apparent conversions are seen. In a typical test cycle, average NOx conversion between 100 and 400 C is 60%. Peak conversion during the down ramp is over 90%, and minimum conversion during the up ramp is 30%. The composition of the effluent gas also varies during the temperature cycle. Intermediates such as methyl nitrate and hydrogen cyanide are not present following the combination of catalysts.

  9. Low-cycle fatigue testing methods

    NASA Technical Reports Server (NTRS)

    Lieurade, H. P.

    1978-01-01

    The good design of highly stressed mechanical components requires accurate knowledge of the service behavior of materials. The main methods for solving the problems of designers are: determination of the mechanical properties of the material after cyclic stabilization; plotting of resistance to plastic deformation curves; effect of temperature on the life on low cycle fatigue; and simulation of notched parts behavior.

  10. Solar High Temperature Water-Splitting Cycle with Quantum Boost

    SciTech Connect

    Taylor, Robin; Davenport, Roger; Talbot, Jan; Herz, Richard; Genders, David; Symons, Peter; Brown, Lloyd

    2014-04-25

    A sulfur family chemical cycle having ammonia as the working fluid and reagent was developed as a cost-effective and efficient hydrogen production technology based on a solar thermochemical water-splitting cycle. The sulfur ammonia (SA) cycle is a renewable and sustainable process that is unique in that it is an all-fluid cycle (i.e., with no solids handling). It uses a moderate temperature solar plant with the solar receiver operating at 800°C. All electricity needed is generated internally from recovered heat. The plant would operate continuously with low cost storage and it is a good potential solar thermochemical hydrogen production cycle for reaching the DOE cost goals. Two approaches were considered for the hydrogen production step of the SA cycle: (1) photocatalytic, and (2) electrolytic oxidation of ammonium sulfite to ammonium sulfate in aqueous solutions. Also, two sub-cycles were evaluated for the oxygen evolution side of the SA cycle: (1) zinc sulfate/zinc oxide, and (2) potassium sulfate/potassium pyrosulfate. The laboratory testing and optimization of all the process steps for each version of the SA cycle were proven in the laboratory or have been fully demonstrated by others, but further optimization is still possible and needed. The solar configuration evolved to a 50 MW(thermal) central receiver system with a North heliostat field, a cavity receiver, and NaCl molten salt storage to allow continuous operation. The H2A economic model was used to optimize and trade-off SA cycle configurations. Parametric studies of chemical plant performance have indicated process efficiencies of ~20%. Although the current process efficiency is technically acceptable, an increased efficiency is needed if the DOE cost targets are to be reached. There are two interrelated areas in which there is the potential for significant efficiency improvements: electrolysis cell voltage and excessive water vaporization. Methods to significantly reduce water evaporation are

  11. 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.

  12. 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.

  13. 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.

  14. 40 CFR 86.1333-90 - Transient test cycle generation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 19 2011-07-01 2011-07-01 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...

  15. 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.

  16. 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).

  17. PDP cycle 1 tests at INEL

    SciTech Connect

    Harker, Y.D.; Twedell, G.W.

    1997-11-01

    The Idaho National Engineering Laboratory (INEL) is a participant in the nondestructive assay Performance Demonstration Program (PDP) as part of the U.S. TRU Waste Characterization Program. The PDP program was designed to help ensure compliance with the quality assurance objectives (QAO`s) in the TRU Waste Characterization Program Plan. In June, 1996, cycle 1 of PDP program was completed at the Stored Waste Examination Pilot Plant (SWEPP) at INEL. The assay capability at INEL/SWEPP consists of a passive active neutron (PAN) radioassay system (for bulk fissile material assay) and a passive gamma spectrometry system (for isotopic mass ratio determination). The results from the two systems are combined to produce a single assay report which contains isotopic information ({sup 238}Pu, {sup 239}Pu), density, total activity, alpha activity, TRU activity, TRU activity concentration, Pu equivalent Curies and fissile gram equivalent. The PDP cycle 1 tests were expected to test bias and precision of the assay systems under nearly ideal conditions; ie., non-interfering matrices and little or no source self shielding. The test consisted of two drums in which the source loading was not known by the site. One drum was essentially empty and the other was filled with ethafoam. As per PDP`s instructions, the tests were to be conducted using the same procedures and equipment that normally would be used by SWEPP to assay real waste drums. This paper will discuss the lessons learned from these tests and INEL`s plans to improve the capabilities of the SWEPP assay systems. 7 refs., 6 tabs.

  18. 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...

  19. 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...) 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...

  20. 40 CFR 90.410 - Engine test cycle.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 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...

  1. 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...

  2. 40 CFR 90.410 - 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. 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...

  3. 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...

  4. 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.

  5. 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...

  6. 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... 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...

  7. 40 CFR 86.336-79 - Diesel engine test cycle.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 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...

  8. 40 CFR 86.336-79 - Diesel engine test cycle.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 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...

  9. Thermal cycling tests on surface-mount assemblies

    SciTech Connect

    Jennings, C.W.

    1988-03-01

    The capability of surface-mount (SM) solder joints to withstand various thermal cycle stresses was evaluated through electrical circuit resistance changes of a test pattern and by visual examination for cracks in the solder after exposure to thermal cycling. The joints connected different electrical components, primarily leadless-chip carriers (LCCs), and printed wiring-board (PWB) pads on different laminate substrates. Laminate compositions were epoxy-glass and polyimide-glass with and without copper/Invar/copper (CIC) inner layers, polyimide-quartz, epoxy-Kevlar, and polyimide-Kevlar. The most resistant joints were between small LCCs (24 and 48 pins) and polyimide-glass laminate with CIC inner layers. Processing in joint formation was found to be an important part of joint resistant. Thermal cycling was varied with respect to both time and temperature. A few resistors, capacitors, and inductors showed opens after 500 30-min cycles between -65/degree/C and 125/degree/C. Appreciable moisture contents were measured for laminate materials, especially those of polyimide-Kevlar after equilibration in 100/percent/ relative humidity at room temperature. If not removed or reduced, moisture can cause delamination in vapor-phase soldering. 17 refs, 12 figs.,10 tabs.

  10. Capacity fade of Sony 18650 cells cycled at elevated temperatures. Part I. Cycling performance

    NASA Astrophysics Data System (ADS)

    Ramadass, P.; Haran, Bala; White, Ralph; Popov, Branko N.

    The capacity fade of Sony 18650 Li-ion cells increases with increase in temperature. After 800 cycles, the cells cycled at RT and 45 °C showed a capacity fade of 30 and 36%, respectively. The cell cycled at 55 °C showed a capacity loss of about 70% after 490 cycles. The rate capability of the cells continues to decrease with cycling. Impedance measurements showed an overall increase in the cell resistance with cycling and temperature. Impedance studies of the electrode materials showed an increased positive electrode resistance when compared to that of the negative electrode for cells cycled at RT and 45 °C. However, cells cycled at 50 and 55 °C exhibit higher negative electrode resistance. The increased capacity fade for the cells cycled at high temperatures can be explained by taking into account the repeated film formation over the surface of anode, which results in increased rate of lithium loss and also in a drastic increase in the negative electrode resistance with cycling.

  11. Thermal Cycling of Mir Cooperative Solar Array (MCSA) Test Panels

    NASA Technical Reports Server (NTRS)

    Hoffman, David J.; Scheiman, David A.

    1997-01-01

    The Mir Cooperative Solar Array (MCSA) project was a joint US/Russian effort to build a photovoltaic (PV) solar array and deliver it to the Russian space station Mir. The MCSA is currently being used to increase the electrical power on Mir and provide PV array performance data in support of Phase 1 of the International Space Station (ISS), which will use arrays based on the same solar cells used in the MCSA. The US supplied the photovoltaic power modules (PPMs) and provided technical and programmatic oversight while Russia provided the array support structures and deployment mechanism and built and tested the array. In order to ensure that there would be no problems with the interface between US and Russian hardware, an accelerated thermal life cycle test was performed at NASA Lewis Research Center on two representative samples of the MCSA. Over an eight-month period (August 1994 - March 1995), two 15-cell MCSA solar array 'mini' panel test articles were simultaneously put through 24,000 thermal cycles (+80 C to -100 C), equivalent to four years on-orbit. The test objectives, facility, procedure and results are described in this paper. Post-test inspection and evaluation revealed no significant degradation in the structural integrity of the test articles and no electrical degradation, not including one cell damaged early as an artifact of the test and removed from consideration. The interesting nature of the performance degradation caused by this one cell, which only occurred at elevated temperatures, is 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 US solar cell modules with the Russian support structure would be able to withstand at least 24,000 thermal cycles (4 years on-orbit).

  12. Cycle life testing of 8-cm mercury ion thruster cathodes

    NASA Technical Reports Server (NTRS)

    Wintucky, E. G.

    1976-01-01

    Two main cathodes have successfully completed 2800 and 1980 cycles and three neutralizers, 3928, 3050, and 2850 cycles in ongoing cycle life tests of flight-type cathode-isolator-vaporizer and neutralizer-isolator-vaporizer assemblies for the 4.45 mN 8-cm Hg ion thruster system. Each cycle included one hour of cathode operation. Starting and operating conditions simulated those expected in a typical auxiliary propulsion mission duty cycle. The cycle life test results are presented along with results of an insert comparison test which led to the selection of a rolled foil insert type for the 8-cm Engineering Model Thruster cathodes.

  13. 40 CFR 91.410 - Engine test cycle.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 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...

  14. 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... excluded from both cycle validation and the integrated work used for emissions calculations. (4)...

  15. 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... Procedures § 86.1341-98 Test cycle validation criteria. Section 86.1341-98 includes text that specifies... excluded from both cycle validation and the integrated work used for emissions calculations. (4)...

  16. A novel high-temperature ejector-topping power cycle

    SciTech Connect

    Freedman, B.Z.; Lior, N. . Dept. of Mechanical Engineering and Applied Mechanics)

    1994-01-01

    A novel, patented topping power cycle is described that takes its energy from a very high-temperature heat source and in which the temperature of the heat sink is still high enough to operate another, conventional power cycle. The top temperatures heat source is used to evaporate a low saturation pressure liquid, which serves as the driving fluid for compressing the secondary fluid in an ejector. Due to the inherently simple construction of ejectors, they are well suited for operation at temperatures higher than those that can be used with gas turbines. The gases exiting from the ejector transfer heat to the lower temperature cycle, and are separated by condensing the primary fluid. The secondary gas is then used to drive a turbine. For a system using sodium as the primary fluid and helium as the secondary fluid, and using a bottoming Rankine steam cycle, the overall thermal efficiency can be at least 11 percent better than that of conventional steam Rankine cycles.

  17. Low-cycle fatigue of a VZh175 high-temperature alloy under elastoplastic deformation conditions

    NASA Astrophysics Data System (ADS)

    Belyaev, M. S.; Terent'ev, V. F.; Bakradze, M. M.; Gorbovets, M. A.; Gol'dberg, M. A.

    2015-04-01

    The low-cycle fatigue of a VZh175 nickel superalloy is studied under conditions of complete deformation per loading cycle at an initial cycle asymmetry R = 0, a deformation amplitude ɛa = 0.4-0.6%, and a temperature of 20 and 650°C. The specific features of cyclic hardening/softening of the alloy under these conditions are detected. The mechanisms of fatigue crack nucleation and growth are analyzed as functions of the deformation amplitude and the test temperature.

  18. Effect of saddle height on skin temperature measured in different days of cycling.

    PubMed

    Priego Quesada, Jose Ignacio; Carpes, Felipe P; Salvador Palmer, Rosario; Pérez-Soriano, Pedro; Cibrián Ortiz de Anda, Rosa M

    2016-01-01

    Infrared thermography can be useful to explore the effects of exercise on neuromuscular function. During cycling, it could be used to investigate the effects of saddle height on thermoregulation. The aim of this study was to examine whether different cycling postures, elicited by different knee flexion angles, could influence skin temperature. Furthermore, we also determined whether the reproducibility of thermal measurements in response to cycling differed in the body regions affected or not affected by saddle height. Sixteen cyclists participated in three tests of 45 min of cycling at their individual 50 % peak power output. Each test was performed in a different knee flexion position on the bicycle (20°, 30°, 40° knee flexion when the pedal crank was at 180°). Different knee angles were obtained by changing saddle height. Skin temperatures were determined by infrared thermography before, immediately after and 10 min after the cycling test, in 16 different regions of interest (ROI) in the trunk and lower limbs. Changes in saddle height did not result in changes in skin temperature in the ROI. However, lower knee flexion elicited higher temperature in popliteus after cycling than higher flexion (p = 0.008 and ES = 0.8), and higher knee flexion elicited lower temperature variation in the tibialis anterior than intermediate knee flexion (p = 0.004 and ES = 0.8). Absolute temperatures obtained good and very good intraday reproducibility in the different measurements (ICCs between 0.44 and 0.85), but temperature variations showed lower reproducibility (ICCs between 0.11 and 0.74). Different postures assumed by the cyclist due to different saddle height did not influence temperature measurements. Skin temperature can be measured on different days with good repeatability, but temperature variations can be more sensitive to the effects of an intervention. PMID:27026901

  19. Effect of Temperature Cycling and Exposure to Extreme Temperatures on Reliability of Solid Tantalum Capacitors

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2007-01-01

    In this work, results of multiple temperature cycling (TC) (up to 1,000 cycles) of different types of solid tantalum capacitors are analyzed and reported. Deformation of chip tantalum during temperature variations simulating reflow soldering conditions was measured to evaluate the possibility of the pop-corning effect in the parts. To simulate the effect of short-time exposures to solder reflow temperatures on the reliability of tantalum capacitors, several part types were subjected to multiple cycles (up to 100) between room temperature and 240 C with periodical measurements of electrical characteristics of the parts. Mechanisms of degradation caused by temperature cycling and exposure to high temperatures, and the requirements of MIL-PRF-55365 for assessment of the resistance of the parts to soldering heat are discussed.

  20. A cycle timer for testing electric vehicles

    NASA Technical Reports Server (NTRS)

    Soltis, R. F.

    1978-01-01

    The paper presents a cycle timer which enables the accurate following and repetition of SAE driving schedules of stop and go cycles, for electric vehicles, by reducing the human factor. The system which consists of a programmable read-only memory (PROM) stores each of these cycles, which are detailed, on its own plug-in card. The actual vehicle speed, and the PROM indicated desired speed are displayed on a dual scale meter allowing the driver to match them. A speed change is preceded by a half second buzzer warning and a new cycle by a one second warning. The PROM controls the recycle start time as well as the buzzer activation. A 5 volt regulator providing logic power, and a 12 volt dc-dc converter providing analog and memory power are described.

  1. 40 CFR 1037.510 - Duty-cycle exhaust testing.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Duty-cycle exhaust testing. 1037.510 Section 1037.510 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES Test and Modeling Procedures § 1037.510 Duty-cycle exhaust testing. This...

  2. 40 CFR 1037.510 - Duty-cycle exhaust testing.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Duty-cycle exhaust testing. 1037.510 Section 1037.510 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES Test and Modeling Procedures § 1037.510 Duty-cycle exhaust testing. This...

  3. 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.

  4. Temperature effects on sealed lead acid batteries and charging techniques to prolong cycle life.

    SciTech Connect

    Hutchinson, Ronda

    2004-06-01

    Sealed lead acid cells are used in many projects in Sandia National Laboratories Department 2660 Telemetry and Instrumentation systems. The importance of these cells in battery packs for powering electronics to remotely conduct tests is significant. Since many tests are carried out in flight or launched, temperature is a major factor. It is also important that the battery packs are properly charged so that the test is completed before the pack cannot supply sufficient power. Department 2665 conducted research and studies to determine the effects of temperature on cycle time as well as charging techniques to maximize cycle life and cycle times on sealed lead acid cells. The studies proved that both temperature and charging techniques are very important for battery life to support successful field testing and expensive flight and launched tests. This report demonstrates the effects of temperature on cycle time for SLA cells as well as proper charging techniques to get the most life and cycle time out of SLA cells in battery packs.

  5. High temperature tensile testing of ceramic composites

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, John Z.; Hemann, John H.

    1988-01-01

    The various components of a high temperature tensile testing system are evaluated. The objective is the high temperature tensile testing of SiC fiber reinforced reaction bonded Si3N4 specimens at test temperatures up to 1650 C (3000 F). Testing is to be conducted in inert gases and air. Gripping fixtures, specimen configurations, furnaces, optical strain measuring systems, and temperature measurement techniques are reviewed. Advantages and disadvantages of the various techniques are also noted.

  6. Cold startup and low temperature performance of the Brayton cycle electrical subsystem

    NASA Technical Reports Server (NTRS)

    Vrancik, J. E.; Bainbridge, R. C.

    1971-01-01

    Cold performance tests and startup tests were conducted on the Brayton-cycle inverter, motor-driven pump, dc supply, speed control with parasitic load resistor and the Brayton control system. These tests were performed with the components in a vacuum and mounted on coldplates. A temperature range of ?25 to -50 C was used for the tests. No failures occurred, and component performance gave no indication that there would be any problem with the safe operation of the Brayton power generating system.

  7. Room Temperature and Elevated Temperature Composite Sandwich Joint Testing

    NASA Technical Reports Server (NTRS)

    Walker, Sandra P.

    1998-01-01

    Testing of composite sandwich joint elements has been completed to verify the strength capacity of joints designed to carry specified running loads representative of a high speed civil transport wing. Static tension testing at both room and an elevated temperature of 350 F and fatigue testing at room temperature were conducted to determine strength capacity, fatigue life, and failure modes. Static tension test results yielded failure loads above the design loads for the room temperature tests, confirming the ability of the joint concepts tested to carry their design loads. However, strength reductions as large as 30% were observed at the elevated test temperature, where all failure loads were below the room temperature design loads for the specific joint designs tested. Fatigue testing resulted in lower than predicted fatigue lives.

  8. Operational Results of a Closed Brayton Cycle Test-Loop

    NASA Astrophysics Data System (ADS)

    Wright, Steven A.; Fuller, Robert; Lipinski, Ronald J.; Nichols, Kenneth; Brown, Nicholas

    2005-02-01

    A number of space and terrestrial power system designs plan to use nuclear reactors that are coupled to Closed-loop Brayton Cycle (CBC) systems to generate electrical power. Because very little experience exists regarding the operational behavior of these systems, Sandia National Laboratories (through its Laboratory Directed Research and Development program) is developing a closed-loop test bed that can be used to determine the operational behavior of these systems and to validate models for these systems. Sandia has contracted Barber-Nichols Corporation to design, fabricate, and assemble a Closed-loop Brayton Cycle (CBC) system. This system was developed by modifying commercially available hardware. It uses a 30 kWe Capstone C-30 gas-turbine unit (www.capstoneturbine.com) with a modified housing that permits the attachment of an electrical heater and a water cooled chiller that are connected to the turbo-machinery in a closed loop. The test-loop reuses the Capstone turbine, compressor, and alternator. The Capstone system's nominal operating point is 1150 K turbine inlet temperature at 96,000 rpm. The annular recuperator and portions of the Capstone control system (inverter) and starter system are also reused. The rotational speed of the turbo-machinery is controlled either by adjusting the alternator load by either using the electrical grid or a separate load bank. This report describes the test-loop hardware SBL-30 (Sandia Brayton Loop-30kWe). Also presented are results of early testing and modeling of the unit. The SBL-30 hardware is currently configured with a heater that is limited to 80 kWth with a maximum outlet temperature of ˜1000 K.

  9. Operational results of a Closed Brayton Cycle test-loop.

    SciTech Connect

    Fuller, Robert; Wright, Steven Alan; Nichols, Kenneth Graham.; Brown, Nicholas; Lipinski, Ronald J.

    2004-11-01

    A number of space and terrestrial power system designs plan to use nuclear reactors that are coupled to Closed-loop Brayton Cycle (CBC) systems to generate electrical power. Because very little experience exists regarding the operational behavior of these systems, Sandia National Laboratories (through its Laboratory Directed Research and Development program) is developing a closed-loop test bed that can be used to determine the operational behavior of these systems and to validate models for these systems. Sandia has contracted Barber-Nichols Corporation to design, fabricate, and assemble a Closed-loop Brayton Cycle (CBC) system. This system was developed by modifying commercially available hardware. It uses a 30 kWe Capstone C-30 gas-turbine unit (www.capstoneturbine.com) with a modified housing that permits the attachment of an electrical heater and a water cooled chiller that are connected to the turbo-machinery in a closed loop. The test-loop reuses the Capstone turbine, compressor, and alternator. The Capstone system's nominal operating point is 1150 K turbine inlet temperature at 96,000 rpm. The annular recuperator and portions of the Capstone control system (inverter) and starter system are also reused. The rotational speed of the turbo-machinery is controlled either by adjusting the alternator load by either using the electrical grid or a separate load bank. This report describes the test-loop hardware SBL-30 (Sandia Brayton Loop-30kWe). Also presented are results of early testing and modeling of the unit. The SBL-30 hardware is currently configured with a heater that is limited to 80 kW{sub th} with a maximum outlet temperature of {approx}1000 K.

  10. Validity of cycle test in air compared to underwater cycling.

    PubMed

    Almeling, M; Schega, L; Witten, F; Lirk, P; Wulf, K

    2006-01-01

    According to international guidelines, fitness to dive is generally assessed using a bicycle stress test (BST) in air. To date, there is no study explicitly addressing the question whether the results of a BST in air really predict performance status under water. Therefore, the aim of the present study was twofold: first, to design an experimental setting allowing the examination of physical performance status under water, and second, to examine whether there is an association of response to exercise in air compared to exercise under water using self contained underwater breathing apparatus (SCUBA). We constructed and evaluated a measurement technique for a bicycle ergometry and for gas analysis under water. Part of the work was the development of a new valve system which allowed to collect the exhaled air in total and to transport it to the spirometer next to the pool. Twenty-eight healthy male divers underwent a BST. Compared to a given workload in air, gross capacity decreased significantly by about 50% underwater. High performance in air was associated with a high performance underwater. The examinations were carried out without any complications. In conclusion, our experimental setting allowed the safe and reliable examination of physical performance status under water. First results indicate that the results of a BST in air correlate well with the cardio-circulatory performance status underwater. A subsequent study with a larger sample size will enable us to more precisely model this correlation. PMID:16602256

  11. Transient temperature and mixing times of quantum walks on cycles

    NASA Astrophysics Data System (ADS)

    Díaz, Nicolás; Donangelo, Raul; Portugal, Renato; Romanelli, Alejandro

    2016-07-01

    The definition of entanglement temperature for a quantum walk on a line is extended to N cycles, which are more amenable to a physical implementation. We show that, for these systems, there is a linear connection between the thermalization time and the mixing time and, also, that these characteristic times become insensitive to the system size when N is larger than a few units.

  12. Cycle life analysis of series connected lithium-ion batteries with temperature difference

    NASA Astrophysics Data System (ADS)

    Chiu, Kuan-Cheng; Lin, Chi-Hao; Yeh, Sheng-Fa; Lin, Yu-Han; Huang, Chih-Sheng; Chen, Kuo-Ching

    2014-10-01

    Within a battery pack of electric vehicles, a constant and homogeneous temperature distribution is an ideal case. However, what is in fact frequently observed is an unbalanced cycle life performance between series/parallel connected cells. While previous studies have proposed models that simulate the capacity fade of a single lithium-ion battery (LIB) in cycle life tests, most of them do not consider the accompanying effects when batteries are connected, and these models could only investigate cycling under a constant cell temperature. To analyze the temperature difference effect on a battery pack, we develop a cycle life model that allows for temperature variation of LIBs during cycling, and we apply the model to the simulation of series connected LIBs based on the porous electrode theory. We assign different hypothetical temperatures to each of the cells in series. Such a design generates a state of performance imbalance. Our result shows that the capacity degradation of the battery pack increases with the increase of temperature difference and of the average temperature. We then conduct an experiment to verify this adverse effect. The experimental data agree well with the simulation result.

  13. 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... 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)...

  14. 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)...

  15. Multiaxial fatigue low cycle fatigue testing

    NASA Technical Reports Server (NTRS)

    Zamrik, S. Y.

    1985-01-01

    Multiaxial testing methods are reviewed. Advantages and disadvantages of each type test is discussed. Significant multiaxial data available in the literature is analyzed. The yield theories are compared for multiaxial fatigue analysis.

  16. Testing Method for Heat Resistance Under Temperature Gradient

    NASA Astrophysics Data System (ADS)

    Takagi, K.; Kawasaki, A.; Itoh, Y.; Harada, Y.; Ono, F.

    2007-12-01

    Testing Method for Heat Resistance under Temperature Gradient” is a Japanese Industrial Standard (JIS) newly established by the Minister of Economy, Trade and Industry, after deliberations by the Japanese Industrial Standards Committee, in accordance with the Industrial Standardization Law. This standard specified the testing method for heat resistance under temperature gradient of materials and coated members of equipment exposed to high temperature, such as aircraft engines, gas turbines, and so on. This paper introduces the principle and overview of the established standard. In addition, taking the heat cycle test using the burner rig for instance, we specifically illustrate the acquirable data and their analysis in the standard. Monitoring of the effective thermal conductivity and acoustic emission particularly enables to the non-destructive evaluation of failure cycle.

  17. 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. PMID:25660627

  18. A comparison of single-cycle versus multi-cycle proof testing strategies

    NASA Technical Reports Server (NTRS)

    Hudak, Stephen J., Jr.; Russell, Dale A.

    1988-01-01

    Proof testing was a useful supplement to conventional nondestructive evaluation (NDE) of space shuttle main engine (SSME) components. Since many of these components involve thin sections and high toughness materials, such as Inconel 718, conventional single-cycle proof test logic is not applicable due to the propensity for stable crack growth during the proof tests. Experience with five-cycle proof testing of SSME components is summarized and a framework is outlined for understanding multi-cycle proof testing using the fracture mechanics concept of a resistance curve. Extreme value statistics are also used to propose an empirical approach to compare the advantages and disadvantages of single- versus multi-cycle proof testing. The importance of the initial flaw size distribution and specimen thickness in such a comparison is also discussed.

  19. Brayton Cycle for High-Temperature Gas-Cooled Reactors

    SciTech Connect

    Oh, Chang H.; Moore, Richard L.

    2005-03-15

    This paper describes research on improving the Brayton cycle efficiency for a high-temperature gas-cooled reactor (HTGR). In this study, we are investigating the efficiency of an indirect helium Brayton cycle for the power conversion side of an HTGR power plant. A reference case based on a 250-MW(thermal) pebble bed HTGR was developed using helium gas as a working fluid in both the primary and power conversion sides. The commercial computer code HYSYS was used for process optimization. A numerical model using the Visual-Basic (V-B) computer language was also developed to assist in the evaluation of the Brayton cycle efficiency. Results from both the HYSYS simulation and the V-B model were compared with Japanese calculations based on the 300-MW(electric) Gas Turbine High-Temperature Reactor (GTHTR) that was developed by the Japan Atomic Energy Research Institute. After benchmarking our models, parametric investigations were performed to see the effect of important parameters on the cycle efficiency. We also investigated single-shaft versus multiple-shaft arrangements for the turbomachinery. The results from this study are applicable to other reactor concepts such as fast gas-cooled reactors, supercritical water reactors, and others.The ultimate goal of this study is to use other fluids such as supercritical carbon dioxide for the HTGR power conversion loop in order to improve the cycle efficiency over that of the helium Brayton cycle. This study is in progress, and the results will be published in a subsequent paper.

  20. Brayton Cycle for High Temperature Gas-Cooled Reactors

    SciTech Connect

    Chang Oh

    2005-03-01

    This paper describes research on improving the Brayton cycle efficiency for a high-temperature gas-cooled reactor (HTGR). In this study, we are investigating the efficiency of an indirect helium Brayton cycle for the power conversion side of an HTGR power plant. A reference case based on a 250-MW(thermal) pebble bed HTGR was developed using helium gas as a working fluid in both the primary and power conversion sides. The commercial computer code HYSYS was used for process optimization. A numerical model using the Visual-Basic (V-B) computer language was also developed to assist in the evaluation of the Brayton cycle efficiency. Results from both the HYSYS simulation and the V-B model were compared with Japanese calculations based on the 300-MW(electric) Gas Turbine High-Temperature Reactor (GTHTR) that was developed by the Japan Atomic Energy Research Institute. After benchmarking our models, parametric investigations were performed to see the effect of important parameters on the cycle efficiency. We also investigated single-shaft versus multiple-shaft arrangements for the turbomachinery. The results from this study are applicable to other reactor concepts such as fast gas-cooled reactors, supercritical water reactors, and others. The ultimate goal of this study is to use other fluids such as supercritical carbon dioxide for the HTGR power conversion loop in order to improve the cycle efficiency over that of the helium Brayton cycle. This study is in progress, and the results will be published in a subsequent paper.

  1. Use of strainrange partitioning to predict high temperature low-cycle fatigue life. [of metallic materials

    NASA Technical Reports Server (NTRS)

    Hirschberg, M. H.; Halford, G. R.

    1976-01-01

    The fundamental concepts of the strainrange partitioning approach to high temperature, low low-cycle fatigue are reviewed. Procedures are presented by which the partitioned strainrange versus life relationships for any material can be generated. Laboratory tests are suggested for further verifying the ability of the method of strainrange partitioning to predict life.

  2. 40 CFR 86.1333 - Transient test cycle generation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... The generation of the maximum torque curve is described in 40 CFR part 1065. (b) Example of the...: ER28AP14.006 Where: Max Test Speed = the maximum test speed as calculated in 40 CFR part 1065. (ii) For Otto-cycle engines: ER28AP14.007 Where: Max Test Speed = the maximum test speed as calculated in 40...

  3. Low cycle fatigue behavior of Zircaloy-2 at room temperature

    NASA Astrophysics Data System (ADS)

    Sudhakar Rao, G.; Chakravartty, J. K.; Nudurupati, Saibaba; Mahobia, G. S.; Chattopadhyay, Kausik; Santhi Srinivas, N. C.; Singh, Vakil

    2013-10-01

    Fuel cladding and pressure tubes of Zircaloy-2 in pressurized light and heavy water nuclear reactors experience plastic strain cycles due to power fluctuations in the reactor, such strain cycles cause low cycle fatigue (LCF) and could be life limiting factor for them. Factors like strain rate, strain amplitude and temperature are known to have marked influence on LCF behavior. The effect of strain rate from 10-2 to 10-4 s-1 on LCF behavior of Zircaloy-2 was studied, at different strain amplitudes between ±0.50% and ±1.25% at room temperature. Fatigue life was decreased with lowering of strain rate from 10-2 to 10-4 s-1 at all the strain amplitudes studied. While there was cyclic softening at lower strain amplitudes (Δεt/2 ⩽ ±0.60%) cyclic hardening was exhibited at higher strain amplitudes (Δεt/2 ⩾ ±1.00%) at all the strain rates. Further, there was secondary cyclic hardening during the later stage of cycling at all the strain amplitudes and the strain rates. Cyclic stress-strain hysteresis loops at the lowest strain rate of 10-4 s-1 were found to be heavily serrated, resulting from dynamic strain aging (DSA). There was significant effect of strain rate on dislocation substructure. The results are discussed in terms of high concentration of point defects generated during cyclic straining and their role in enhancing interaction between solutes and dislocations.

  4. Intermediate Temperature Water Heat Pipe Tests

    NASA Technical Reports Server (NTRS)

    Devarakonda, Angirasa; Xiong, Da-Xi; Beach, Duane E.

    2005-01-01

    Heat pipes are among the most promising technologies for space radiator systems. Water heat pipes are explored in the intermediate temperature range of 400 to above 500 K. The thermodynamic and thermo-physical properties of water are reviewed in this temperature range. Test data are reported for a copper-water heat pipe. The heat pipe was tested under different orientations. Water heat pipes show promise in this temperature range. Fabrication and testing issues are being addressed.

  5. Intermediate Temperature Water Heat Pipe Tests

    NASA Technical Reports Server (NTRS)

    Devarakonda, Angirasa; Xiong, Daxi; Beach, Duane E.

    2004-01-01

    Heat pipes are among the most promising technologies for space radiator systems. Water heat pipes are explored in the intermediate temperature range of 400 to above 500 K. The thermodynamic and thermo-physical properties of water are reviewed in this temperature range. Test Data are reported for a copper-water heat pipe. The heat pipe was tested under different orientations. Water heat pipes show promise in this temperature range.Fabrication and testing issues are being addressed.

  6. Temperature-entropy formulation of thermoelectric thermodynamic cycles.

    PubMed

    Chua, H T; Ng, K C; Xuan, X C; Yap, C; Gordon, Jeffrey M

    2002-05-01

    A temperature-entropy formulation is derived for thermoelectric devices. Thermoelectric chiller and generator cycles can then be cast in the same irreversible thermodynamics framework commonly applied to conventional large-scale cooling and power generation equipment, including a transparent identification of the principal energy flows and performance bottlenecks (dissipation). Distinct differences in chiller versus generator mode are highlighted and illustrated with data from commercial thermoelectric units. PMID:12059651

  7. Elevated temperature fiber push-out testing

    SciTech Connect

    Eldridge, J.I.

    1995-10-01

    The potential use of fiber-reinforced composite materials for high temperature applications makes the development of interface test methodology at those high temperatures very desirable. A facility for performing high temperature fiber push-out tests will be described with emphasis on critical issues in experimental procedure. Examples from several composite systems illustrate the temperature dependence and environmental sensitivity of fiber debonding and sliding. Interpretation of the temperature dependence will be made primarily in terms of changes in residual stresses along with additional effects due to changes in matrix ductility and interfacial wear. Examples will show that high temperature fiber push-out testing can often distinguish between chemical and frictional fiber/matrix bonding in cases where room temperature only testing cannot.

  8. Cycle life of nickel-hydrogen cells. II - Accelerated cycle life test

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

    A cycle life test of nickel-hydrogen (Ni/H2) cells containing electrolytes of various KOH concentrations and a sintered-type nickel electrode were carried out at 23 C using a 45-min accelerated low earth orbit (LEO) cycle regime at 80 percent depth of discharge. Ten cells containing 21 to 36 percent KOH were tested. Since this accelerated test regime accelerated the cycle life roughly twice as fast as a typical LEO regime, the present results indicate that the cells with 26 percent KOH may last over 5 years in an 80 percent depth-of-discharge cycling in an LEO regime. Cells with lower KOH concentrations (21 to 23.5 percent) also showed longer cycle life than those with KOH concentrations of 31 percent or higher, although the life was shorter than those with 26 percent KOH.

  9. KOH concentration effect on cycle life of nickel-hydrogen cells. III - Cycle life test

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

    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.

  10. Electrochemical and physical analysis of a Li-ion cell cycled at elevated temperature

    SciTech Connect

    Shim, Joongpyo; Kostecki, Robert; Richardson, Thomas; Song, Xiangyun; Striebel, Kathryn A.

    2002-06-21

    Laboratory-size LiNi0.8Co0.15Al0.05O2/graphite lithium-ion pouch cells were cycled over 100 percent DOD at room temperature and 60 degrees C in order to investigate high-temperature degradation mechanisms of this important technology. Capacity fade for the cell was correlated with that for the individual components, using electrochemical analysis of the electrodes and other diagnostic techniques. The high-temperature cell lost 65 percent of its initial capacity after 140 cycles at 60 degrees C compared to only 4 percent loss for the cell cycled at room temperature. Cell ohmic impedance increased significantly with the elevated temperature cycling, resulting in some of loss of capacity at the C/2 rate. However, as determined with slow rate testing of the individual electrodes, the anode retained most of its original capacity, while the cathode lost 65 percent, even when cycled with a fresh source of lithium. Diagnostic evaluation of cell components including XRD, Raman, CSAFM and suggest capacity loss occurs primarily due to a rise in the impedance of the cathode, especially at the end-of-charge. The impedance rise may be caused in part by a loss of the conductive carbon at the surface of the cathode and/or by an organic film on the surface of the cathode that becomes non-ionically conductive at low lithium content.

  11. Integrated Efficiency Test for Pyrochemical Fuel Cycles

    SciTech Connect

    S. X. Li; D. Vaden; B. R. Westphal; G. L. Fredrickson; R. W. Benedict; T. A. Johnson

    2009-05-01

    An engineering-scale integrated efficiency test was conducted with sodium-bonded, spent EBR-II drive fuel elements. The major pieces of equipment involved in the test were the element chopper, Mk-IV electrorefiner, cathode processor, and casting furnace. Four electrorefining batches (containing 50.4 kg HM) were processed under a set of fixed operating parameters that have been developed for the equipment based on over a decade’s worth of processing experience. A mass balance around this equipment was performed. Actinide dissolution and recovery efficiencies were established based on the mass balance and chemical analytical results of various samples taken from process streams during the integrated efficiency test.

  12. 40 CFR 89.410 - Engine test cycle.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... to the discrete-mode duty cycles specified in this section, as described in 40 CFR 1039.505. ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Engine test cycle. 89.410 Section 89...) CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES Exhaust Emission...

  13. 40 CFR 89.410 - Engine test cycle.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... to the discrete-mode duty cycles specified in this section, as described in 40 CFR 1039.505. ... 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...

  14. 40 CFR 89.410 - Engine test cycle.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... to the discrete-mode duty cycles specified in this section, as described in 40 CFR 1039.505. ... 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...

  15. 40 CFR 89.410 - Engine test cycle.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... engines are certified in an engine family that includes primarily non-marine diesel engines, and the... to the discrete-mode duty cycles specified in this section, as described in 40 CFR 1039.505. ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Engine test cycle. 89.410 Section...

  16. 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 ...

  17. Fracture resistance of Zr-Nb alloys under low-cycle fatigue tests

    NASA Astrophysics Data System (ADS)

    Nikulin, S. A.; Rozhnov, A. B.; Gusev, A. Yu.; Nechaykina, T. A.; Rogachev, S. O.; Zadorozhnyy, M. Yu.

    2014-03-01

    Comparative low-cycle fatigue tests of small-scale specimens cut from the cladding tubes of E110, E125, E110opt zirconium alloys at temperatures of 25 and 350 °C using a dynamic mechanical analyzer have been carried out. It is shown that the limited cycles fatigue stress for all alloys is 50% less at temperature of 350 °C comparing to 25 °C. Besides it has been revealed that the limited cycles fatigue stress increases with increasing the strength of zirconium alloy.

  18. On massive carbide precipitation during high temperature low cycle fatigue in alloy 800H

    NASA Technical Reports Server (NTRS)

    Sankararao, K. Bhanu; Schuster, H.; Halford, G. R.

    1994-01-01

    The effect of strain rate on massive precipitation and the mechanism for the occurrence of massive precipitation of M23C6 in alloy 800H is investigated during elevated temperature low cycle fatigue testing. It was observed that large M23C6 platelets were in the vicinity of grain and incoherent twin boundaries. The strain controlled fatigue testing at higher strain rates that promoted cyclic hardening enabled massive precipitation to occur more easily.

  19. 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...

  20. 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...) 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...

  1. Elevated temperature alters carbon cycling in a model microbial community

    NASA Astrophysics Data System (ADS)

    Mosier, A.; Li, Z.; Thomas, B. C.; Hettich, R. L.; Pan, C.; Banfield, J. F.

    2013-12-01

    Earth's climate is regulated by biogeochemical carbon exchanges between the land, oceans and atmosphere that are chiefly driven by microorganisms. Microbial communities are therefore indispensible to the study of carbon cycling and its impacts on the global climate system. In spite of the critical role of microbial communities in carbon cycling processes, microbial activity is currently minimally represented or altogether absent from most Earth System Models. Method development and hypothesis-driven experimentation on tractable model ecosystems of reduced complexity, as presented here, are essential for building molecularly resolved, benchmarked carbon-climate models. Here, we use chemoautotropic acid mine drainage biofilms as a model community to determine how elevated temperature, a key parameter of global climate change, regulates the flow of carbon through microbial-based ecosystems. This study represents the first community proteomics analysis using tandem mass tags (TMT), which enable accurate, precise, and reproducible quantification of proteins. We compare protein expression levels of biofilms growing over a narrow temperature range expected to occur with predicted climate changes. We show that elevated temperature leads to up-regulation of proteins involved in amino acid metabolism and protein modification, and down-regulation of proteins involved in growth and reproduction. Closely related bacterial genotypes differ in their response to temperature: Elevated temperature represses carbon fixation by two Leptospirillum genotypes, whereas carbon fixation is significantly up-regulated at higher temperature by a third closely related genotypic group. Leptospirillum group III bacteria are more susceptible to viral stress at elevated temperature, which may lead to greater carbon turnover in the microbial food web through the release of viral lysate. Overall, this proteogenomics approach revealed the effects of climate change on carbon cycling pathways and other

  2. Elevation of Continuous Low-Cycle Fatigue Behaviour of High Temperature P122 Boiler Material

    SciTech Connect

    Pumwa, John; Soo Woo Nam

    2002-07-01

    The complex thermal-mechanical loading of power-generating plant components usually comprises of creep, high-cycle and low-cycle fatigue which are thermally induced by start-ups, load changes and shut-downs, producing in-stationary temperature gradients and hence creating strain as well as stress fields. In order to select the correct materials for these hostile environmental conditions, it is vitally important to understand the behaviour of mechanical properties of these materials. This paper reports the results of Low-cycle fatigue tests of P122 (HCM12A or 12Cr-1.8W-1.5Cu) high temperature boiler material, which is one of the latest developed materials for high temperature environments. The tests were conducted at temperatures ranging from 550 deg. C to 700 deg. C at 50 deg. C intervals with strain ranges of {+-}1.5 to {+-}3.0% at 0.5% intervals using a closed-loop hydraulic Instron material testing machine with a servo hydraulic controller. The results confirm that P122 is comparable to conventional high temperature steels. Moreover, the fracture mode assessments strongly revealed a ductile transgranular fracture mode. (authors)

  3. Cycle 10 WFPC2 Flood Preflash Test

    NASA Astrophysics Data System (ADS)

    Biretta, John

    2001-07-01

    The data from this new proposal will allow an assessment of the effect of a super-preflash, such as the one suggested by Janesick {Scientific Charge-Coupled Devices, James R. Janesick, SPIE Press Monograph, 2001}, on the CTE performance of WFPC2. Previous WFPC2 preflash calibration programs have successfully tested the effects of relatively low preflashes {or fat zeros} on the CTE, in order to determine the optimum level at which the CTE problems are minimized. Typical preflash exposures from these proposals added 50-10000 electrons. However, in his new book, Janesick {2001} suggests that radiation-induced traps can not be completely eliminated with low-level preflashes, that such a preflash merely exposes the incoming photons to new traps. Instead, he recommends the use of a light flood, effectively super-preflashing the chips to levels 2-3 times full well, reading out the preflash, then taking external images.

  4. Spatial patterns in timing of the diurnal temperature cycle

    NASA Astrophysics Data System (ADS)

    Holmes, T. R. H.; Crow, W. T.; Hain, C.

    2013-05-01

    This paper investigates the structural difference in timing of the diurnal temperature cycle (DTC) over land resulting from choice of measuring device or model framework. It is shown that the timing can be reliably estimated from temporally sparse observations acquired from a constellation of low Earth orbiting satellites given record lengths of at least three months. Based on a year of data, the spatial patterns of mean DTC timing are compared between Ka-band temperature estimates, geostationary thermal infrared (TIR) temperature estimates and numerical weather prediction model output from the Global Modeling and Assimilation Office (GMAO). It is found that the spatial patterns can be explained by vegetation effects, sensing depth differences and more speculatively the orientation of orographic relief features. In absolute terms, the GMAO model puts the peak of the DTC on average at 12:50 local solar time, 23 min before TIR with a peak temperature at 13:13. Since TIR is the shallowest observation of the land surface, this small difference represents a structural error that possibly affects the models ability to assimilate observations that are closely tied to the DTC. For non-desert areas, the Ka-band observations have only a small delay of about 15 min with the TIR observations which is in agreement with their respective theoretical sensing depth. The results of this comparison provide insights into the structural differences between temperature measurements and models, and can be used as a first step to account for these differences in a coherent way.

  5. Effect of drink temperature on core temperature and endurance cycling performance in warm, humid conditions.

    PubMed

    Burdon, Catriona; O'Connor, Helen; Gifford, Janelle; Shirreffs, Susan; Chapman, Phillip; Johnson, Nathan

    2010-09-01

    The aims of this study were to determine the effect of cold (4 °C) and thermoneutral (37 °C) beverages on thermoregulation and performance in the heat and to explore sensory factors associated with ingesting a cold stimulus. Seven males (age 32.8 ± 6.1 years, [V(.)]O(2peak) 59.4 ± 6.6 ml x kg(-1) x min(-1)) completed cold, thermoneutral, and thermoneutral + ice trials in randomized order. Participants cycled for 90 min at 65%[V(.)]O(2peak) followed by a 15-min performance test at 28 °C and 70% relative humidity. They ingested 2.3 ml x kg(-1) of a 7.4% carbohydrate-electrolyte solution every 10 min during the 90-min steady-state exercise including 30 ml ice puree every 5 min in the ice trial. Absolute changes in skin temperature (0.22 ± 1.1 °C vs. 1.14 ± 0.9 °C; P = 0.02), mean body temperature (1.2 ± 0.3 vs. 1.6 ± 0.3 °C; P = 0.03), and heat storage were lower across the 90-min exercise bout for the cold compared with the thermoneutral trial. Significant improvements (4.9 ± 2.4%, P < 0.01) in performance were observed with cold but no significant differences were detected with ice. Consumption of cold beverages during prolonged exercise in the heat improves body temperature measures and performance. Consumption of ice did not reveal a sensory response, but requires further study. Beverages consumed by athletes exercising in the heat should perhaps be cold for performance and safety reasons. PMID:20694887

  6. SRF Performance of CEBAF After Thermal Cycle to Ambient Temperature

    SciTech Connect

    Robert Rimmer; Jay Benesch; Joseph Preble; Charles Reece

    2005-05-01

    In September 2003, in the wake of Hurricane Isabel, JLab was without power for four days after a tree fell on the main power lines feeding the site. This was long enough to lose insulating vacuum in the cryomodules and cryogenic systems resulting in the whole accelerator warming up and the total loss of the liquid helium inventory. This thermal cycle stressed many of the cryomodule components causing several cavities to become inoperable due to helium to vacuum leaks. At the same time the thermal cycle released years of adsorbed gas from the cold surfaces. Over the next days and weeks this gas was pumped away, the insulating vacuum was restored and the machine was cooled back down and re-commissioned. In a testament to the robustness of SRF technology, only a small loss in energy capability was apparent, although individual cavities had quite different field-emission characteristics compared to before the event. In Summer 2004 a section of the machine was again cycled to room temperature during the long maintenance shutdown. We report on the overall SRF performance of the machine after these major disturbances and on efforts to characterize and optimize the new behavior for high-energy running.

  7. 40 CFR 86.1333-2010 - Transient test cycle generation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... less than four seconds. (See 40 CFR 1065.514 for allowances in the cycle validation criteria.) (d... engines: ER13JY05.001 Where: MaxTestSpeed = the maximum test speed as calculated in 40 CFR part 1065. (ii... CFR part 1065. (2) Torque is normalized to the maximum torque at the rpm listed with it. Therefore,...

  8. 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 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM (CONTINUED) ENHANCED PRUDENTIAL STANDARDS (REGULATION YY) Company-Run Stress Test Requirements for...

  9. 40 CFR 1037.510 - Duty-cycle exhaust testing.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... differences are consistent with the criteria as specified in 40 CFR part 1066. If the speeds do not conform to these criteria, the test is not valid and must be repeated. (e) Run test cycles as specified in 40 CFR... we determine this would be unrepresentative of in-use operation as specified in 40 CFR...

  10. Results of accelerated thermal cycle tests of solar cells modules

    NASA Technical Reports Server (NTRS)

    Berman, P.; Mueller, R.; Salama, M.; Yasui, R.

    1976-01-01

    Various candidate solar panel designs were evaluated, both theoretically and experimentally, with respect to their thermal cycling survival capability, and in particular with respect to an accelerated simulation of thermal cycles representative of Viking '75 mission requirements. The experimental results were obtained on 'mini-panels' thermally cycled in a newly installed automated test facility herein described. The resulting damage was analyzed physically and theoretically, and on the basis of these analyses the panel design was suitably modified to significantly improve its ability to withstand the thermal environment. These successful modifications demonstrate the value of the complementary theoretical-experimental approach adopted, and discussed in detail in this paper.

  11. Test Plan for the Bearing Dust Cycle Test

    NASA Technical Reports Server (NTRS)

    Gunderson, Katelyn; Aitchison, Lindsay

    2014-01-01

    The overall objective of these experiments is to test the dust-resistant seal on the high performance glove disconnect system (HPGD), to analyze the response of the bearing to lunar regolith simulant effects.

  12. Analysis of Low Temperature Organic Rankine Cycles for Solar Applications

    NASA Astrophysics Data System (ADS)

    Li, Yunfei

    The present work focuses on Organic Rankine Cycle (ORC) systems and their application to low temperature waste heat recovery, combined heat and power as well as off-grid solar power generation applications. As CO_2 issues come to the fore front and fossil fuels become more expensive, interest in low grade heat recovery has grown dramatically in the past few years. Solar energy, as a clean, renewable, pollution-free and sustainable energy has great potential for the use of ORC systems. Several ORC solutions have been proposed to generate electricity from low temperature sources. The ORC systems discussed here can be applied to fields such as solar thermal, biological waste heat, engine exhaust gases, small-scale cogeneration, domestic boilers, etc. The current work presents a thermodynamic and economic analysis for the use of ORC systems to convert solar energy or low exergy energy to generate electrical power. The organic working fluids investigated here were selected to investigate the effect of the fluid saturation temperature on the performance of ORCs. The working fluids under investigation are R113, R245fa, R123, with boiling points between 40°C and 200°C at pressures from 10 kPa to 10 MPa. Ambient temperature air at 20oC to 30oC is utilized as cooling resource, and allowing for a temperature difference 10°C for effective heat transfer. Consequently, the working fluids are condensed at 40°C. A combined first- and second-law analysis is performed by varying some system independent parameters at various reference temperatures. The present work shows that ORC systems can be viable and economical for the applications such as waste heat use and off-grid power generation even though they are likely to be more expensive than grid power.

  13. 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.

  14. TEMPERATURE DEPENDANT BEHAVIOUR OBSERVED IN THE AFIP-6 IRRADIATION TEST

    SciTech Connect

    A. B. Robinson; D. M. Wachs; P. Medvedev; S.J. Miller; F. J. Rice; M. K. Meyer; D. M. Perez

    2012-03-01

    The AFIP-6 test assembly was irradiated for one cycle in the Advanced Test Reactor at Idaho National Laboratory. The experiment was designed to test two monolithic fuel plates at power and burn-ups which bounded the operating conditions of both ATR and HFIR driver fuel. Both plates contained a solid U-Mo fuel foil with a zirconium diffusion barrier between 6061-aluminum cladding plates bonded by hot isostatic pressing. The experiment was designed with an orifice to restrict the coolant flow in order to obtain prototypic coolant temperature conditions. While these coolant temperatures were obtained, the reduced flow resulted in a sufficiently low heat transfer coefficient that failure of the fuel plates occurred. The increased fuel temperature led to significant variations in the fission gas retention behaviour of the U-Mo fuel. These variations in performance are outlined herein.

  15. High-Temperature-Turbine Technology Program: Phase II. Technology test and support studies. Update of overall plant-design description-combined-cycle electric-power plant with integrated low-Btu-gas plant

    SciTech Connect

    Not Available

    1982-04-01

    Changes made to the preliminary design of a commercial combined cycle electric powerplant operating on low Btu gas fuel are described. Major elements changed were: gas turbine configuration; gas desulfurization system; gas cleanup system; and the steam system operating parameters. The net power output of this base load station was increased from 750 MW to 1032 MW, by increasing the size of the four gas turbines. The gas turbine configuration was changed from a 2-spool, annular burner arrangement to a single shaft engine with can-type combustors. Firing temperature is revised from 3000 to 2750/sup 0/F. The free power turbine arrangement of the original powerplant concept which permits double-ending the electrical generators was retained. The steam system configuration is changed from an 1800/1000 single level system to a 2400/1000/1000 single reheat configuration which utilizes heat extraction from the hot flue gas down to 280/sup 0/F, delivers gasifier steam and jacket water and provides fuel gas preheat. The steam system produces 376.MW of electrical power. The high temperature gas desulfurization and cleanup system of the original powerplant design is replaced by a cold water wash and a commercial Selexol desulfurization unit. This change produced a substantial reduction in overall powerplant efficiency, but was necessary because the previously-used developmental hot gas cleanup system has not advanced to commercial status. The Lurgi fixed bed gasifier utilized in the original powerplant concept was retained. The modular arrangement of the original powerplant design was retained. The overall powerplant coal pile to bus bar efficiency is 40.5%, conservatively based on demonstrated performance of individual commercial or near-commercial components utilized in the design.

  16. High-Cycle Fatigue Properties at Cryogenic Temperatures in INCONEL 718

    NASA Astrophysics Data System (ADS)

    Ono, Y.; Yuri, T.; Sumiyoshi, H.; Takeuchi, E.; Matsuoka, S.; Ogata, T.

    2006-03-01

    High-cycle fatigue properties at 4 K, 20 K, 77 K and 293 K were investigated in forged-INCONEL 718 nickel-based superalloy with a mean gamma (γ) grain size of 25 μm. In the present material, plate-like delta phase precipitated at γ grain boundaries and niobium (Nb)-enriched MC type carbides precipitated coarsely throughout the specimens. The 0.2% proof stress and the tensile strength of this alloy increased with decreasing temperature, without decreasing elongation or reduction of area. High-cycle fatigue strengths also increased with decreasing temperature although the fatigue limit at each temperature didn't appear even around 107 cycles. Fatigue cracks initiated near the specimen surface and formed faceted structures around crack initiation sites. Fatigue cracks predominantly initiated from coarse Nb-enriched carbides and faceted structures mainly corresponded to these carbides. In lower stress amplitude tests, however, facets were formed through transgranular crack initiation and growth. These kinds of distinctive crack initiation behavior seem to lower the high-cycle fatigue strength below room temperature in the present material.

  17. High-Cycle Fatigue Properties at Cryogenic Temperatures in INCONEL 718

    SciTech Connect

    Ono, Y.; Yuri, T.; Sumiyoshi, H.; Takeuchi, E.; Ogata, T.; Matsuoka, S.

    2006-03-31

    High-cycle fatigue properties at 4 K, 20 K, 77 K and 293 K were investigated in forged-INCONEL 718 nickel-based superalloy with a mean gamma ({gamma}) grain size of 25 {mu}m. In the present material, plate-like delta phase precipitated at {gamma} grain boundaries and niobium (Nb)-enriched MC type carbides precipitated coarsely throughout the specimens. The 0.2% proof stress and the tensile strength of this alloy increased with decreasing temperature, without decreasing elongation or reduction of area. High-cycle fatigue strengths also increased with decreasing temperature although the fatigue limit at each temperature didn't appear even around 107 cycles. Fatigue cracks initiated near the specimen surface and formed faceted structures around crack initiation sites. Fatigue cracks predominantly initiated from coarse Nb-enriched carbides and faceted structures mainly corresponded to these carbides. In lower stress amplitude tests, however, facets were formed through transgranular crack initiation and growth. These kinds of distinctive crack initiation behavior seem to lower the high-cycle fatigue strength below room temperature in the present material.

  18. Analysis of a Temperature-Controlled Exhaust Thermoelectric Generator During a Driving Cycle

    NASA Astrophysics Data System (ADS)

    Brito, F. P.; Alves, A.; Pires, J. M.; Martins, L. B.; Martins, J.; Oliveira, J.; Teixeira, J.; Goncalves, L. M.; Hall, M. J.

    2016-03-01

    Thermoelectric generators can be used in automotive exhaust energy recovery. As car engines operate under wide variable loads, it is a challenge to design a system for operating efficiently under these variable conditions. This means being able to avoid excessive thermal dilution under low engine loads and being able to operate under high load, high temperature events without the need to deflect the exhaust gases with bypass systems. The authors have previously proposed a thermoelectric generator (TEG) concept with temperature control based on the operating principle of the variable conductance heat pipe/thermosiphon. This strategy allows the TEG modules’ hot face to work under constant, optimized temperature. The variable engine load will only affect the number of modules exposed to the heat source, not the heat transfer temperature. This prevents module overheating under high engine loads and avoids thermal dilution under low engine loads. The present work assesses the merit of the aforementioned approach by analysing the generator output during driving cycles simulated with an energy model of a light vehicle. For the baseline evaporator and condenser configuration, the driving cycle averaged electrical power outputs were approximately 320 W and 550 W for the type-approval Worldwide harmonized light vehicles test procedure Class 3 driving cycle and for a real-world highway driving cycle, respectively.

  19. Effects of temperature and hold times on low cycle fatigue of Astroloy

    NASA Technical Reports Server (NTRS)

    Choe, S. J.; Stoloff, N. S.; Duquette, D. J.

    1986-01-01

    Low cycle fatigue (LCF) and creep-fatigue-environment interactions of HIP Astroloy were studied at 650 C and 725 C. The results showed that the model proposed by Kaisand and Mowbray (1979) was successful in predicting the magnitude and trend of the fatigue crack growth rate from LCF data. Raising the temperature from 650 C to 725 C did not change the fracture mode, while employing tensile hold caused a change in fracture mode and was more damaging than raising the temperature by 75 C. All samples displayed multiple fracture origins, which is initiated transgranularly in continuous cycling tests and intergranularly in hold time tests. An examination of the secondary crack showed no apparent creep damage. Oxidation in high purity argon appeared to be the major factor in LCF life degradation due to hold time.

  20. Vacuum thermal-mechanical fatigue testing of two iron base high temperature alloys

    NASA Technical Reports Server (NTRS)

    Sheffler, K. D.

    1974-01-01

    Ultrahigh vacuum elevated temperature low cycle fatigue and thermal fatigue tests of 304 stainless steel and A-286 alloy have shown significant effects of frequency and combined temperature-strain cycling on fatigue life. At constant temperature, the cyclic life of both alloys was lower at lower frequencies. Combined temperature-strain cycling reduced fatigue life with respect to isothermal life at the maximum temperature of the thermal cycle. Life reductions with in-phase thermal cycling (tension at high temperature, compression at low temperature) were attributed to grain boundary cavitation caused by unreversed tensile grain boundary sliding. The proposed mechanism for out-of-phase cavity generation involved accumulation of unreversed compressive grain boundary displacements which could not be geometrically accomodated by intragranular deformation in the low-ductility A-286 alloy.

  1. Acoustic testing of high temperature panels

    NASA Astrophysics Data System (ADS)

    Leatherwood, Jack D.; Clevenson, Sherman A.; Powell, Clemans A.; Daniels, Edward F.

    1990-10-01

    Results are presented of a series of thermal-acoustic tests conducted on the NASA Langley Research Center Thermal-Acoustic Test Apparatus to (1) investigate techniques for obtaining strain measurements on metallic and carbon-carbon materials at elevated temperature; (2) document the dynamic strain response characteristics of several superalloy honeycomb thermal protection system panels at elevated temperatures of up to 1200 F; and (3) determine the strain response and sonic fatigue behavior of four carbon-carbon panels at both ambient and elevated temperatures. A second study tested four carbon-carbon panels to document panel dynamic response characteristics at ambient and elevated temperature, determine time to failure and faliure modes, and collect continuous strain data up to panel failure. Strain data are presented from both types of panels, and problems encountered in obtaining reliable strain data on the carbon-carbon panels are described. The failure modes of the carbon-carbon panels are examined.

  2. Temperature and Strain-Rate Effects on Low-Cycle Fatigue Behavior of Alloy 800H

    NASA Technical Reports Server (NTRS)

    Rao, K. Bhanu Sankara; Schiffers, H.; Schuster, H.; Halford, G. R.

    1996-01-01

    The effects of strain rate (4 x 10(exp -6) to 4 x 10(exp -3)/s) and temperature on the Low-Cycle Fatigue (LCF) behavior of alloy 800H have been evaluated in the range 750 C to 950 C. Total axial strain controlled LCF tests were conducted in air at a strain amplitude of +/- 0.30 pct. LCF life decreased with decreasing strain rate and increasing temperature. The cyclic stress response behavior showed a marked variation with temperature and strain rate. The time- and temperature- dependent processes which influence the cyclic stress response and life have been identified and their relative importance assessed. Dynamic strain aging, time-dependent deformation, precipitation of parallel platelets of M(23)C6 on grain boundaries and incoherent ledges of twins, and oxidation were found to operate depending on the test conditions. The largest effect on life was shown by oxidation processes.

  3. Toughness variation with test temperature and

    NASA Astrophysics Data System (ADS)

    German, R. M.; Hanafee, J. E.; Digiallonardo, S. L.

    1984-01-01

    A two phase heavy alloy composite based on 95 W-3.5 Ni-1.5 Fe (wt pct) was fabricated from elemental powders by liquid phase sintering. Past reports on the heavy alloys indicate considerable disagreement concerning cooling rate effects on toughness. The present experiments determined the effect of both cooling rate and test temperature on the properties of the 95 W heavy alloy. This alloy undergoes a ductile to brittle transition with decreasing test temperature; the transition temperature is close to room temperature. The cooling rate from post-sintering anneals carried out at temperatures greater than 1000 °C has a large influence on toughness; rapid quenching gives superior toughness. These findings support an impurity segregation explanation for embrittlement in the heavy alloys.

  4. Outer planet spacecraft temperature testing and analysis

    NASA Technical Reports Server (NTRS)

    Hoffman, A. R.; Avila, A.

    2002-01-01

    Unmanned spacecraft flown on missions to the outer planets of the solar system have included flybys, planetary orbiters, and atmospheric probes during the last three decades. The thermal design, test, and analysis approach applied to these spacecraft evolved from the passive thermal designs applied to the earlier lunar and interplanetary spacecraft. The inflight temperature data from representative sets of engineering subsystems and science instruments from a subset of these spacecraft are compared to those obtained during the ground test programs and from the prelaunch predictions. Several lessons are presented with specific recommendations for considerations for new projects to aid in the planning of cost effective temperature design, test, and analysis programs.

  5. Status of the integrated topping cycle and MHD generator testing

    SciTech Connect

    Pian, C.C.P.; Dunton, A.W.; Schmitt, E.W.; Morrison, D.J.

    1993-12-31

    The status of the Integrated Topping Cycle (ITC) MHD generator testing is presented. This generator is part of a 50 MW{sub t} prototypic powertrain that is currently undergoing proof-of-concept (POC) testing at the U.S. Department of Energy`s Component Development and Integration Facility in Butte, Montana. Test objectives are to establish component lifetimes at prototypic operating conditions and to verify the design performance parameters. The ITC generator has completed Design Verification Testing and is now well into the POC duration test. To date (May 1, 1993), over 360 hours of the planned 1000 hours of testing has been completed. Generator testing is being performed at conditions representative of commercial power plant operating conditions. Prototypic generator channel hardware is performing very well. Based on test results obtained thus far, the prognosis is excellent for meeting all of the POC test objectives.

  6. Temperature distortion generator for turboshaft engine testing

    NASA Technical Reports Server (NTRS)

    Klann, G. A.; Barth, R. L.; Biesiadny, T. J.

    1984-01-01

    The procedures and unique hardware used to conduct an experimental investigation into the response of a small-turboshaft-engine compression system to various hot gas ingestion patterns are presented. The temperature distortion generator described herein uses gaseous hydrogen to create both steady-state and time-variant, or transient, temperature distortion at the engine inlet. The range of transient temperature ramps produced by the distortion generator during the engine tests was from less than 111 deg K/sec (200 deg R/sec) to above 611 deg K/sec (1100 deg R/sec); instantaneous temperatures to 422 deg K (760 deg R) above ambient were generated. The distortion generator was used to document the maximum inlet temperatures and temperature rise rates that the compression system could tolerate before the onset of stall for various circumferential distortions as well as the compressor system response during stall.

  7. Spatial patterns in timing of the diurnal temperature cycle

    NASA Astrophysics Data System (ADS)

    Holmes, T. R. H.; Crow, W. T.; Hain, C.

    2013-10-01

    This paper investigates the structural difference in timing of the diurnal temperature cycle (DTC) over land resulting from choice of measuring device or model framework. It is shown that the timing can be reliably estimated from temporally sparse observations acquired from a constellation of low Earth-orbiting satellites given record lengths of at least three months. Based on a year of data, the spatial patterns of mean DTC timing are compared between temperature estimates from microwave Ka-band, geostationary thermal infrared (TIR), and numerical weather prediction model output from the Global Modeling and Assimilation Office (GMAO). It is found that the spatial patterns can be explained by vegetation effects, sensing depth differences and more speculatively the orientation of orographic relief features. In absolute terms, the GMAO model puts the peak of the DTC on average at 12:50 local solar time, 23 min before TIR with a peak temperature at 13:13 (both averaged over Africa and Europe). Since TIR is the shallowest observation of the land surface, this small difference represents a structural error that possibly affects the model's ability to assimilate observations that are closely tied to the DTC. The equivalent average timing for Ka-band is 13:44, which is influenced by the effect of increased sensing depth in desert areas. For non-desert areas, the Ka-band observations lag the TIR observations by only 15 min, which is in agreement with their respective theoretical sensing depth. The results of this comparison provide insights into the structural differences between temperature measurements and models, and can be used as a first step to account for these differences in a coherent way.

  8. 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.

  9. Component test program for variable-cycle engines

    NASA Technical Reports Server (NTRS)

    Powers, A. G.; Whitlow, J. B.; Stitt, L. E.

    1976-01-01

    Variable cycle engine (VCE) concepts for a supersonic cruise aircraft were studied. These VCE concepts incorporate unique critical components and flow path arrangements that provide good performance at both supersonic and subsonic cruise and appear to be economically and environmentally viable. Certain technologies were identified as critical to the successful development of these engine concepts and require considerable development and testing. The feasibility and readiness of the most critical VCE technologies, was assessed, a VCE component test program was initiated. The variable stream control engine (VSCE) component test program, tested and evaluated an efficient low emission duct burner and a quiet coannular ejector nozzle at the rear of a rematched F100 engine.

  10. Effect of an aerodynamic helmet on head temperature, core temperature, and cycling power compared with a traditional helmet.

    PubMed

    Lee, Joshua F; Brown, Skyler R; Lange, Andrew P; Brothers, R Matthew

    2013-12-01

    Nonvented "aerodynamic helmets" reduce wind resistance but may increase head (Th) and gastrointestinal (Tgi) temperature and reduce performance when worn in hot conditions. This study tested the hypothesis that Th and Tgi would be greater during low-intensity cycling (LIC) in the heat while wearing an aero helmet (AERO) vs. a traditional vented racing helmet (REG). This study also tested the hypothesis that Th, Tgi, and finish time would be greater, and power output would be reduced during a self-paced time trial in the heat with AERO vs. REG. Ten highly trained heat-acclimated endurance athletes conducted LIC (50% V[Combining Dot Above]O2max, LIC) and a high-intensity 12-km self-paced time trial (12-km TT) on a cycle ergometer in 39° C on 2 different days (AERO and REG), separated by >48 hours. During LIC, Th was higher at minute 7.5 and all time points thereafter in AERO vs. REG (p < 0.05). Similarly, during the 12-km TT, Th was higher at minutes 12.5, 15, and 17.5 in AERO vs. REG (p < 0.05). Heart rate (HR) and Tgi increased during LIC and during 12-km TT (both p < 0.001); however, no significant interaction (helmet × time) existed for HR or Tgi at either intensity (all p > 0.05). No group differences existed for finish time or power output during the 12-km TT (both p > 0.05). In conclusion, Th becomes elevated during cycling in the heat with an aero helmet compared with a traditional vented racing helmet during LIC and high-intensity cycling, yet Tgi and HR responses are similar irrespective of helmet type and Th. Furthermore, the higher Th that develops when an aero helmet is worn during cycling in the heat does not affect power output or cycling performance during short-duration high-intensity events. PMID:23539083

  11. Intermediate Temperature Fluids Life Tests - Experiments

    NASA Technical Reports Server (NTRS)

    Anderson, William G.; Bonner, Richard W.; Dussinger, Peter M.; Hartenstine, John R.; Sarraf, David B.; Locci, Ivan E.

    2007-01-01

    There are a number of different applications that could use heat pipes or loop heat pipes (LHPs) in the intermediate temperature range of 450 to 725 K (170 to 450 C), including space nuclear power system radiators, fuel cells, and high temperature electronics cooling. Historically, water has been used in heat pipes at temperatures up to about 425 K (150 C). Recent life tests, updated below, demonstrate that titanium/water and Monel/water heat pipes can be used at temperatures up to 550 K (277 C), due to water's favorable transport properties. At temperatures above roughly 570 K (300 C), water is no longer a suitable fluid, due to high vapor pressure and low surface tension as the critical point is approached. At higher temperatures, another working fluid/envelope combination is required, either an organic or halide working fluid. An electromotive force method was used to predict the compatibility of halide working fluids with envelope materials. This procedure was used to reject aluminum and aluminum alloys as envelope materials, due to their high decomposition potential. Titanium and three corrosion resistant superalloys were chosen as envelope materials. Life tests were conducted with these envelopes and six different working fluids: AlBr3, GaCl3, SnCl4, TiCl4, TiBr4, and eutectic diphenyl/diphenyl oxide (Therminol VP-1/Dowtherm A). All of the life tests except for the GaCl3 are ongoing; the GaCl3 was incompatible. As the temperature approaches 725 K (450 C), cesium is a potential heat pipe working fluid. Life tests results are also presented for cesium/Monel 400 and cesium/70-30 copper/nickel heat pipes operating near 750 K (477 C). These materials are not suitable for long term operation, due to copper transport from the condenser to the evaporator.

  12. 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.

  13. 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.

  14. Stability Test for Transient-Temperature Calculations

    NASA Technical Reports Server (NTRS)

    Campbell, W.

    1984-01-01

    Graphical test helps assure numerical stability of calculations of transient temperature or diffusion in composite medium. Rectangular grid forms basis of two-dimensional finite-difference model for heat conduction or other diffusion like phenomena. Model enables calculation of transient heat transfer among up to four different materials that meet at grid point.

  15. Debranching and temperature-cycled crystallization of waxy rice starch and their digestibility.

    PubMed

    Zeng, Feng; Ma, Fei; Gao, Qunyu; Yu, Shujuan; Kong, Fansheng; Zhu, Siming

    2014-11-26

    Slowly digestible starch (SDS) was obtained through debranched waxy rice starch and subsequent crystallization under isothermal and temperature-cycled conditions. Temperature-cycled crystallization of dual 4/-20 °C produced a higher yield of SDS product than isotherm crystallization. Crystal structure of SDS products changed from A-type to a mixture of B and V-type X-ray diffraction patterns. The relative crystallinity was higher in the temperature-cycled samples than that of isotherm. Attenuated total reflectance Fourier transform infrared spectroscopy suggested that the peripheral regions of isothermal storage starch were better organized than temperature-cycles. Temperature cycling induced higher onset temperature for melting of crystals than isothermal storage under a differential scanning calorimeter. The cycled temperature storage induced a greater amount of SDS than the isothermal storage. PMID:25256463

  16. Temperature buffer test design, instrumentation and measurements

    NASA Astrophysics Data System (ADS)

    Sandén, Torbjörn; Goudarzi, Reza; de Combarieu, Michel; Åkesson, Mattias; Hökmark, Harald

    The Temperature Buffer Test, TBT, is a heated full-scale field experiment carried out jointly by ANDRA and SKB at the SKB Äspö Hard Rock Laboratory in Southeast Sweden. An existing 8 m deep, 1.8 m diameter KBS-3-type deposition hole located at -420 m level has been selected for the test. The objectives are to improve the general understanding of Thermo-Hydro-Mechanical, THM, behavior of buffer materials submitted to severe thermal conditions with temperatures well over 100 °C during water uptake of partly saturated bentonite-based buffer materials, and to check, in due time, their properties after water saturation. The test includes two carbon steel heating canisters each 3 m high and 0.6 m diameter, surrounded by 0.6 m of buffer material. There is a 0.2 m thick sand shield between the upper heater and the surrounding bentonite, while the lower heater is surrounded by bentonite only. On top of the stack of bentonite blocks is a confining plug anchored to the rock. In the slot between buffer and rock wall is a sand filter equipped with pipes to control the water pressure at the boundary, which is seldom done with an EBS in situ experiment. Both heater mid-height planes are densely instrumented in order to follow, with direct or indirect methods, buffer THM evolution. Temperature, relative humidity, stress and pore pressure have been monitored since the test start in March 2003. Total water inflow is also monitored. Firstly, the present paper describes the test design, the instrumentation, the plug anchoring system and the system for water boundary pressure control. Second, having described the test, the paper shows different measurements that illustrate evolution of temperature, saturation, suction and swelling pressure in the upper and the lower buffer.

  17. Developing and Testing Water Cycle Intensification Indicator (WCI) over the United States

    NASA Astrophysics Data System (ADS)

    Feng, X.; Houser, P. R.

    2014-12-01

    Is the water cycle intensifying in response to global warming due to temperature-driven changes in atmospheric water holding capacity? To address this question, we are developing and testing Water Cycle Intensification Indicator (WCI) to quantify the current and future change in the strength of the water cycle across the conterminous U.S. in support of the National Climate Assessment (NCA). The WCI consists of a suite of primary water cycle trend and extreme composites that are spatially- and temporally-scalable for summarizing how the climate changes results in stronger or more extreme water cycling over the nation. We calculated trend and extreme in water cycle components using NASA-produced data and modeling products. Six water cycle variables are chosen, including precipitation, evaporation, runoff, moisture convergence flux, terrestrial storage and water vapor. Our preliminary results showed that the strength of water cycle depends on specific regions and variables, even different datasets. For instance, precipitation from MERRA-Land offline simulation is consistent with the CPC unified precipitation dataset in showing positive trend over the northeastern, northwestern and west north central, but negative trend over the western and central regions. However, negative trends are observed in MERRA-land over the southern Texas and some parts of the southern coast, contrary to the positive trend revealed by the unified dataset in the same area. Next, we are going to integrate and combine the trends and extremes of these water cycle components to develop a suite of climate indicators to monitor the changes of water cycle as result of climate change. These indicators will be implemented and tested over the nation for further optimization. Moreover, we will also be developing innovative WCI visualization, documentation and distribution methods to disseminate WCI products to the public and stakeholders.

  18. Tests of alternative reductants in the second uranium purification cycle

    SciTech Connect

    Thompson, M.C.

    1980-05-01

    Miniature mixer-settler tests of the second uranium purification cycle show that plutonium cannot be removed by hydroxylamine-hydrazine (NH/sub 2/OH-N/sub 2/H/sub 4/) because the acidity is too high, or by 2,5-di-t-pentylhydroquinone because HNO/sub 3/ oxidizes the hydroquinone. Plutonium can be removed satisfactorily when U(IV)-hydrazine is used as the reductant.

  19. Ceramic high temperature receiver design and tests

    SciTech Connect

    Davis, S.B.

    1982-07-01

    The High Temperature Solar Thermal Receiver, which was tested a Edwards AFB, CA during the winter of 1980-1981, evolved from technologies developed over a five year period of work. This receiver was tested at the Army Solar Furnace at White Sands, NM in 1976. The receiver, was tested successfully at 1768 deg F and showed thermal efficiencies of 85%. The results were sufficiently promising to lead ERDA to fund our development and test of a 250 kW receiver to measure the efficiency of an open cavity receiver atop a central tower of a heliostat field. This receiver was required to be design scalable to 10, 50, and 100 MW-electric sizes to show applicability to central power tower receivers. That receiver employed rectangular silicon carbide panels and vertical stanchions to achieve scalability. The construction was shown to be fully scalable, and the receiver was operated at temperatures up to 2000 deg F to achieve the performance goals of the experiment during tests at the GIT advanced components test facility during the fall of 1978.

  20. Ceramic high temperature receiver design and tests

    NASA Technical Reports Server (NTRS)

    Davis, S. B.

    1982-01-01

    The High Temperature Solar Thermal Receiver, which was tested a Edwards AFB, CA during the winter of 1980-1981, evolved from technologies developed over a five year period of work. This receiver was tested at the Army Solar Furnace at White Sands, NM in 1976. The receiver, was tested successfully at 1768 deg F and showed thermal efficiencies of 85%. The results were sufficiently promising to lead ERDA to fund our development and test of a 250 kW receiver to measure the efficiency of an open cavity receiver atop a central tower of a heliostat field. This receiver was required to be design scalable to 10, 50, and 100 MW-electric sizes to show applicability to central power tower receivers. That receiver employed rectagular silicon carbide panels and vertical stanchions to achieve scalability. The construction was shown to be fully scalable; and the receiver was operated at temperatures up to 2000 deg F to achieve the performance goals of the experiment during tests at the GIT advanced components test facility during the fall of 1978.

  1. Ultrasonic waveguide transducer for high temperature testing of ceramic honeycomb

    NASA Astrophysics Data System (ADS)

    Wang, N.; An, C. P.; Nickerson, S. T.; Gunasekaran, N.; Shi, Z.

    2013-01-01

    This paper describes the development of a practical ultrasonic waveguide transducer designed for in situ material property characterization of ceramic honeycomb at high temperatures (>1200°C) and under fast thermal cycles (>1000°C/min). The low thermal conductivity MACOR waveguide allows the use of conventional transducer (max temp. 50°C) at one end and guides ultrasonic waves into the high temperature region where the characterization is carried out. The impact of time, temperature, and heating/cooling rates on the material behavior was studied. It was demonstrated that the same transducer could also be used for in-situ crack detection during the thermal shock testing of ceramic honeycomb.

  2. Low Cycle Fatigue and Creep-Fatigue Behavior of Alloy 617 at High Temperature

    SciTech Connect

    Cabet, Celine; Carroll, Laura; Wright, Richard

    2013-10-01

    Alloy 617 is the leading candidate material for an intermediate heat exchanger (IHX) application of the Very High Temperature Nuclear Reactor (VHTR), expected to have an outlet temperature as high as 950 degrees C. Acceptance of Alloy 617 in Section III of the ASME Code for nuclear construction requires a detailed understanding of the creep-fatigue behavior. Initial creep-fatigue work on Alloy 617 suggests a more dominant role of environment with increasing temperature and/or hold times evidenced through changes in creep-fatigue crack growth mechanism/s and failure life. Continuous cycle fatigue and creep-fatigue testing of Alloy 617 was conducted at 950 degrees C and 0.3% and 0.6% total strain in air to simulate damage modes expected in a VHTR application. Continuous cycle specimens exhibited transgranular cracking. Intergranular cracking was observed in the creep-fatigue specimens, although evidence of grain boundary cavitation was not observed. Despite the absence of grain boundary cavitation to accelerate crack propagation, the addition of a hold time at peak tensile strain was detrimental to cycle life. This suggests that creepfatigue interaction may occur by a different mechanism or that the environment may be partially responsible for accelerating failure.

  3. Simulated Lunar Testing of Metabolic Heat Regenerated Temperature Swing Adsorption

    NASA Technical Reports Server (NTRS)

    Padilla, Sebastian A.; Bower, Chad E.; Iacomini, Christie S.; Paul, Heather L.

    2012-01-01

    Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed for thermal and carbon dioxide (CO2) control for a Portable Life Support System (PLSS), as well as water recycling. An Engineering Development Unit (EDU) of the MTSA Subassembly (MTSAS) was designed and assembled for optimized Martian operations, but also meets system requirements for lunar operations. For lunar operations the MTSA sorption cycle is driven via a vacuum swing between suit ventilation loop pressure and lunar vacuum. The focus of this effort was testing in a simulated lunar environment. This environment was simulated in Paragon's EHF vacuum chamber. The objective of the testing was to evaluate the full cycle performance of the MTSA Subassembly EDU, and to assess CO2 loading and pressure drop of the wash coated aluminum reticulated foam sorbent bed. Lunar environment testing proved out the feasibility of pure vacuum swing operation, making MTSA a technology that can be tested and used on the Moon prior to going to Mars. Testing demonstrated better than expected CO2 Nomenclature loading on the sorbent and nearly replicates the equilibrium data from the sorbent manufacturer. This exceeded any of the previous sorbent loading tests performed by Paragon. Subsequently, the increased performance of the sorbent bed design indicates future designs will require less mass and volume than the current EDU rendering MTSA as very competitive for Martian PLSS applications.

  4. 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.

  5. Life-cycle testing of receiving waters with Ceriodaphnia dubia

    SciTech Connect

    Stewart, A.J.; Konetsky, B.K.

    1996-12-31

    Seven-day tests with Ceriodaphnia dubia are commonly used to estimate toxicity of effluents or receiving waters but can sometimes yield {open_quotes}no toxicity{close_quotes} outcomes even if pollutants are present. We conducted two sets of full life-cycle tests with C. dubia to (1) see if tests with longer exposure periods would reveal evidence for toxicity that might not be evident from 7-day tests, and (2) determine the relative importance of water quality versus food as factors influencing C. dubia reproduction. In the first set of tests, C. dubia was reared in diluted mineral water (negative control), water from a stream impacted by coal fly-ash, or water from a retention basin containing sediments contaminated with mercury, other metals and polychlorinated biphenyls. The second set of tests used water from the retention basin only, but this water was either filtered or not filtered, and food was either added or not added, prior to testing. C. dubia survival and reproduction did not differ much among the three water types in the first set of tests, but these two parameters were strongly affected by the filtering and food-addition treatments in the second set of tests. Thus, C. dubia appeared to be relatively insensitive to general water-quality factors, but quite sensitive to food-related factors. Regression analyses showed that the predictability of life-time reproduction by C. dubia from the results of 7-day tests was very low (R{sup 2}< 0.35) in five of the six experiments. The increase in predictability as a function of test duration also differed among water types in the first set of tests, and among treatments in the second set of tests. Thus, 7-day tests with C. dubia may be used to quantify water-quality problems, but it may not be possible to reliably extrapolate the results of these tests to longer time scales.

  6. Intermediate Temperature Fluids Life Tests - Theory

    NASA Technical Reports Server (NTRS)

    Tarau, Calin; Sarraf, David B.; Locci, Ivan E.; Anderson, William G.

    2008-01-01

    There are a number of different applications that could use heat pipes or loop heat pipes (LHPs) in the intermediate temperature range of 450 to 750 K, including space nuclear power system radiators, and high temperature electronics cooling. Potential working fluids include organic fluids, elements, and halides, with halides being the least understood, with only a few life tests conducted. Potential envelope materials for halide working fluids include pure aluminum, aluminum alloys, commercially pure (CP) titanium, titanium alloys, and corrosion resistant superalloys. Life tests were conducted with three halides (AlBr3, SbBr3, and TiCl4) and water in three different envelopes: two aluminum alloys (Al-5052, Al-6061) and Cp-2 titanium. The AlBr3 attacked the grain boundaries in the aluminum envelopes, and formed TiAl compounds in the titanium. The SbBr3 was incompatible with the only envelope material that it was tested with, Al-6061. TiCl4 and water were both compatible with CP2-titanium. A theoretical model was developed that uses electromotive force differences to predict the compatibility of halide working fluids with envelope materials. This theory predicts that iron, nickel, and molybdenum are good envelope materials, while aluminum and titanium halides are good working fluids. The model is in good agreement with results form previous life tests, as well as the current life tests.

  7. 11S4P ABSL18650 Module High DoD Cycling Tests

    NASA Astrophysics Data System (ADS)

    Simon, E.; Buckle, R.; Simmons, N.; Thwaite, C.

    2011-10-01

    An 11s4p ABSL18650HC module is tested under high Depth of Discharge (DoD) continuous cycling at 20°C. The module is charged up to 90% State of Charge (SoC). After 3300 cycles, the capacity loss observed is 17%, the internal cell resistance has increased by 60 to 85%, the end of discharge temperature has increased by about 4°C. The cells degradation observed is not as high as the degradation predicted by ABSL tools, LIFE and BEAST. The four strings exhibit different behaviour. The cells remain balanced, with a maximum end of charge voltage spread around 70 mV. A second 11s 4p ABSL18650HC module is tested under GEO (GEOsynchronous) conditions. After 264 days of GEO cycling, the EOCV dispersion is around 9 mV for the four strings.

  8. The Impact of Elevated Temperatures on Continental Carbon Cycling in the Paleogene

    NASA Astrophysics Data System (ADS)

    Pancost, R. D.; Handley, L.; Taylor, K. W.; Collinson, M. E.; Weijers, J.; Talbot, H. M.; Hollis, C. J.; Grogan, D. S.; Whiteside, J. H.

    2010-12-01

    Recent climate and biogeochemical modelling suggests that methane flux from wetlands and soils was greater during past greenhouse climates, due to a combination of higher continental temperatures, an enhanced hydrological cycle, and elevated primary production. Here, we examine continental environments in the Paleogene using a range of biomarker proxies (complemented by palaeobotanical approaches), including air temperatures derived from the distribution of soil bacterial glycerol dialkyl glycerol tetraethers (the MBT/CBT proxy), as well as evidence from wetland and lacustrine settings for enhanced methane cycling. Previously published and new MBT/CBT records parallel sea surface temperature records, suggesting elevated continental temperatures during the Eocene even at mid- to high latitudes (New Zealand, 20-28°C; the Arctic, 17°C; across the Sierra Nevada, 15-25°C; and SE England, 20-30°C). Such temperatures are broadly consistent with paleobotanical records and would have directly led to increased methane production via the metabolic impact of temperature on rates of methanogenesis. To test this, we have determined the distributions and carbon isotopic compositions of archaeal ether lipids and bacterial hopanoids in thermally immature Eocene lignites. In particular, the Cobham lignite, deposited in SE England and spanning the PETM, is characterised by markedly higher concentrations of both methanogen and methanotroph biomarkers compared to modern and Holocene temperate peats. Elevated temperatures, by fostering either stratification and/or decreased oxygen solubility, could have also led to enhanced methane production in Paleogene lakes. Both the Messel Shale (Germany) and Green River Formation, specifically the Parachute Creek oil shale horizons (Utah and Wyoming), are characterised by strongly reducing conditions (including euxinic conditions in the latter), as well as abundant methanogen and methanotroph biomarkers. Such results confirm model predictions

  9. Feasibility Investigation for Performing Fireball Temperature Tests

    NASA Technical Reports Server (NTRS)

    Tapphorn, Ralph M.; Kurtz, Joe

    1997-01-01

    NASA Johnson Space Center White Sands Test Facility (WSTF) was requested by the Launch Abort Subpanel and the Power Systems Subpanel of the Interagency Nuclear Safety Review Panel to investigate the feasibility of using spectroscopic techniques to measure propellant fireball gas temperatures. This report outlines the modeling and experimental approaches and results of this investigation. Descriptions of the theoretical particle temperature and mass effusion models are presented along with the results of the survivability of small plutonium dioxide (less than or equal to 1000 microns diameter) particles entrained in various propellant fireball scenarios. The experimental test systems used to measure the hydroxide radical, water, and particle graybody spectral emissions and absorptions are discussed. Spectral results along with temperatures extracted by analyzing the spectral features are presented for the flames investigated in the laboratory environment. Methods of implementing spectroscopic measurements for future testing using the WSTF Large-scale Hydrogen/Oxygen Explosion Facility are discussed, and the accuracy expected for these measurements is estimated from laboratory measurements.

  10. Low Temperature Waste Immobilization Testing Vol. I

    SciTech Connect

    Russell, Renee L.; Schweiger, Michael J.; Westsik, Joseph H.; Hrma, Pavel R.; Smith, D. E.; Gallegos, Autumn B.; Telander, Monty R.; Pitman, Stan G.

    2006-09-14

    The Pacific Northwest National Laboratory (PNNL) is evaluating low-temperature technologies to immobilize mixed radioactive and hazardous waste. Three waste forms—alkali-aluminosilicate hydroceramic cement, “Ceramicrete” phosphate-bonded ceramic, and “DuraLith” alkali-aluminosilicate geopolymer—were selected through a competitive solicitation for fabrication and characterization of waste-form properties. The three contractors prepared their respective waste forms using simulants of a Hanford secondary waste and Idaho sodium bearing waste provided by PNNL and characterized their waste forms with respect to the Toxicity Characteristic Leaching Procedure (TCLP) and compressive strength. The contractors sent specimens to PNNL, and PNNL then conducted durability (American National Standards Institute/American Nuclear Society [ANSI/ANS] 16.1 Leachability Index [LI] and modified Product Consistency Test [PCT]) and compressive strength testing (both irradiated and as-received samples). This report presents the results of these characterization tests.

  11. Evaluation of Package Stress during Temperature Cycling using Metal Deformation Measurement and FEM Simulation

    SciTech Connect

    Hoeglauer, J.; Bohm, C.; Otremba, R.; Maerz, J.; Nelle, P.; Stecher, M.; Alpern, P.

    2006-02-07

    Plastic encapsulated devices that are exposed to Temperature Cycling (TC) tests undergo an excessive mechanical stress due to different Coefficients of Thermal Expansion (CTE) of the various materials used in the system. Especially in the corners of the die, passivation cracks and shifted metal lines can be observed, which demonstrates an increasing mechanical stress from chip center to the corners of the die. This effect has been known for a long time. This paper presents a simple measurement technique to quantify the mechanical shear stress at the chip-Mold Compound (MC) interface by measuring the deformation of a periodical metal structure. Based on this deformation measurement, we evaluated the stress distribution within the package, and the influence of different parameters such as number of cycles and chip size. Furthermore, these experimental results were compared with FEM simulation, and showed good agreement but could not account in all cases for the total amount of observed shift.

  12. Testing of reciprocating seals for application in a Stirling cycle engine

    NASA Technical Reports Server (NTRS)

    Curulla, J. F.; Beck, T. L.

    1980-01-01

    Six single stage reciprocating seal configurations to the requirements of the Stirling cycle engine were evaluated. The seals tested were: the Boeing Footseal, NASA Chevron polyimide seal, Bell seal, Quad seal, Tetraseal, and Dynabak seal. None of these seal configurations met the leakage goals of .002 cc/sec at helium gas pressure of 1.22 x 10 to the 7th power PA, rod speed of 7.19 m/sec peak, and seal environmental temperature of 408 K for 1500 hours. Most seals failed due to high temperatures. Catastrophic failures were observed for a minimum number of test runs characterized by extremely high leakage rates and large temperature rises. The Bell seal attained 63 hours of run time at significantly lowered test conditions.

  13. Daily Cycle of Air Temperature and Surface Temperature in Stone Forest

    NASA Astrophysics Data System (ADS)

    Wang, K.; Li, Y.; Wang, X.; Yuan, M.

    2013-12-01

    Urbanization is one of the most profound human activities that impact on climate change. In cities, where are highly artificial areas, the conflict between human activity and natural climate is particularly prominent. Urban areas always have the larger area of impervious land, the higher consumption of greenhouse gases, more emissions of anthropogenic heat and air pollution, all contribute to the urban warming phenomena. Understanding the mechanisms causing a variety of phenomena involved in the urban warming is critical to distinguish the anthropogenic effect and natural variation in the climate change. However, the exact dynamics of urban warming were poorly understood, and effective control strategies are not available. Here we present a study of the daily cycle of air temperature and surface temperature in Stone Forest. The specific heat of the stones in the Stone Forest and concrete of the man-made structures within the cities are approximate. Besides, the height of the Stone Forest and the height of buildings within the city are also similar. As a scenic area, the Stone Forest is being preserved and only opened for sightseeing. There is no anthropogenic heat, as well air pollution within the Stone Forest. The thermal environment in Stone Forest can be considered to be a simulation of thermal environment in the city, which can reveal the effect of man-made structures on urban thermal environment. We conducted the field studies and numerical analysis in the Stone Forest for 4 typical urban morphology and environment scenarios, including high-rise compact cities, low-rise sparse cities, garden cities and isolated single stone. Air temperature and relative humidity were measured every half an hour in 15 different locations, which within different spatial distribution of stones and can represent the four urban scenarios respectively. At the same time, an infrared camera was used to take thermal images and get the hourly surface temperatures of stones and

  14. Ion Exchange Temperature Testing with SRF Resin

    SciTech Connect

    Russell, Renee L.; Rinehart, Donald E.; Brown, Garrett N.; Peterson, Reid A.

    2012-03-01

    Ion exchange using the Spherical Resorcinol-Formaldehyde (SRF) resin has been selected by the U.S. Department of Energy’s Office of River Protection for use in the Pretreatment Facility of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and for potential application in an at-tank deployment for removing 137Cs. Recent proposed changes to the WTP ion exchange process baseline indicate that higher temperatures (50°C) to alleviate post-filtration precipitation issues prior to reaching the ion exchange columns may be required. Therefore, it is important to understand the behavior of SRF resin performance under the conditions expected with the new equipment and process changes. This research examined the impact of elevated temperature on resin loading and resin degradation during extended solution flow using elevated temperature (45°, 50°, 55°, 60°, 65°, 75°C). Testing for extended times at elevated temperatures showed that the resin does degrade and loading capacity is reduced at and above 45°C. Above 60°C the resin appears to not load at all.

  15. The influence of temperature on the cycle life performance of rechargeable Li-TiS2 cells

    NASA Technical Reports Server (NTRS)

    Shen, D. H.; Subbarao, S.; Huang, C.-K.; Deligiannis, F.; Halpert, G.

    1990-01-01

    The authors report studies on the influence of low temperature on the properties and cycling performance of six selected electrolytes. The electrolytes investigated were 2-MeTHF, EC/2-MeTHF, THF, THF/2-MeTHF, EC/THF, and EC/THF/2-MeTHF. All the electrolytes contained 1.5M LiAsF6. Open circuit stand tests indicated that organic electrolytes exhibited improved stability towards lithium at 10 C. However, cycling of the cells at 10 C did not result in improved cycle life performance.

  16. Life Cycle Tests on a Hollow Cathode Based Plasma Contactor

    NASA Technical Reports Server (NTRS)

    Vaughn, Jason A.; Schneider, Todd A.; Munafo, Paul (Technical Monitor)

    2001-01-01

    The propulsive Small Expendable Deployer System (ProSEDS) mission is designed to provide an on-orbit demonstration of the electrodynamic propulsion capabilities of tethers in space. The ProSEDS experiment will be a secondary payload on a Delta II unmanned expendable booster with a mission duration of 12 days. A 5-km conductive tether is attached to the Delta II second stage and collects current from the low Earth orbit (LEO) plasma, and a Hollow Cathode Plasma Contactor (HCPC) emits the collected electrons from the Delta II, completing the electrical circuit to the ambient plasma. The HCPC for the ProSEDS mission have made it necessary to turn off the HCPC once a minute throughout the entire mission. Because of the unusual operating requirements by the ProSEDS mission, an engineering development unit of the HCPC was built to demonstrate the HCPC design would start reliably for the life of the ProSEDS mission. During the life test the engineering unit cycled for over 10,000 on/off cycles without missing a single start, and during that same test the HCPC unit demonstrated the capability to emit 0 to 5 A electron emission current. The performance of the HCPC unit during this life test will be discussed.

  17. MAVRIC Flutter Model Transonic Limit Cycle Oscillation Test

    NASA Technical Reports Server (NTRS)

    Edwards, John W.; Schuster, David M.; Spain, Charles V.; Keller, Donald F.; Moses, Robert W.

    2001-01-01

    The Models for Aeroelastic Validation Research Involving Computation semi-span wind-tunnel model (MAVRIC-I), a business jet wing-fuselage flutter model, was tested in NASA Langley's Transonic Dynamics Tunnel with the goal of obtaining experimental data suitable for Computational Aeroelasticity code validation at transonic separation onset conditions. This research model is notable for its inexpensive construction and instrumentation installation procedures. Unsteady pressures and wing responses were obtained for three wingtip configurations clean, tipstore, and winglet. Traditional flutter boundaries were measured over the range of M = 0.6 to 0.9 and maps of Limit Cycle Oscillation (LCO) behavior were made in the range of M = 0.85 to 0.95. Effects of dynamic pressure and angle-of-attack were measured. Testing in both R134a heavy gas and air provided unique data on Reynolds number, transition effects, and the effect of speed of sound on LCO behavior. The data set provides excellent code validation test cases for the important class of flow conditions involving shock-induced transonic flow separation onset at low wing angles, including Limit Cycle Oscillation behavior.

  18. Mysterious diel cycles of mercury emission from soils held in the dark at constant temperature

    SciTech Connect

    Zhang, Hong; Kuiken, Todd; Lindberg, Steven Eric

    2008-01-01

    It is well known that mercury (Hg) emission from soils is largely controlled by solar radiation and soil temperature, exhibiting diel cycles that closely follow diel variations of solar radiation. To study soil Hg emission processes, we conducted experiments by measuring soil Hg emission fluxes under controlled conditions in the laboratory with a dynamic flux chamber using outside ambient air as flushing air. Unexpectedly, we observed consistent, recurring diel cycles of Hg emissions from dry soils held at constant temperature in the dark in our laboratory. The peaks of the emissions also seemed subject to some seasonal variation and to respond to local weather conditions with lower flux peaks in wintertime and on cloudy or rainy days. Finally, much lower soil Hg emission fluxes were observed in the presence of Hg-free zero air than in the presence of outside ambient air. It is hypothesized that some unidentified air-borne substance(s) in the ambient air might be responsible for the observed diel cycles of soil Hg emission. Further elaborate mechanistic investigations are clearly needed to test the initial working hypotheses and uncover the cause for this interesting, mysterious phenomenon. The present work and recent finding of enhancement of Hg emissions from soil and mineral particles by O3 seem to point to a research need to probe the possible role of near-ground atmospheric chemistry in Hg air/soil exchange.

  19. A Comparison of Single-Cycle Versus Multiple-Cycle Proof Testing Strategies

    NASA Technical Reports Server (NTRS)

    McClung, R. C.; Chell, G. G.; Millwater, H. R.; Russell, D. A.; Millwater, H. R.

    1999-01-01

    Single-cycle and multiple-cycle proof testing (SCPT and MCPT) strategies for reusable aerospace propulsion system components are critically evaluated and compared from a rigorous elastic-plastic fracture mechanics perspective. Earlier MCPT studies are briefly reviewed. New J-integral estimation methods for semielliptical surface cracks and cracks at notches are derived and validated. Engineering methods are developed to characterize crack growth rates during elastic-plastic fatigue crack growth (FCG) and the tear-fatigue interaction near instability. Surface crack growth experiments are conducted with Inconel 718 to characterize tearing resistance, FCG under small-scale yielding and elastic-plastic conditions, and crack growth during simulated MCPT. Fractography and acoustic emission studies provide additional insight. The relative merits of SCPT and MCPT are directly compared using a probabilistic analysis linked with an elastic-plastic crack growth computer code. The conditional probability of failure in service is computed for a population of components that have survived a previous proof test, based on an assumed distribution of initial crack depths. Parameter studies investigate the influence of proof factor, tearing resistance, crack shape, initial crack depth distribution, and notches on the MCPT versus SCPT comparison. The parameter studies provide a rational basis to formulate conclusions about the relative advantages and disadvantages of SCPT and MCPT. Practical engineering guidelines are proposed to help select the optimum proof test protocol in a given application.

  20. A Comparison of Single-Cycle Versus Multiple-Cycle Proof Testing Strategies

    NASA Technical Reports Server (NTRS)

    McClung, R. C.; Chell, G. G.; Millwater, H. R.; Russell, D. A.; Orient, G. E.

    1996-01-01

    Single-cycle and multiple-cycle proof testing (SCPT and MCPT) strategies for reusable aerospace propulsion system components are critically evaluated and compared from a rigorous elastic-plastic fracture mechanics perspective. Earlier MCPT studies are briefly reviewed. New J-integral estimation methods for semi-elliptical surface cracks and cracks at notches are derived and validated. Engineering methods are developed to characterize crack growth rates during elastic-plastic fatigue crack growth (FCG) and the tear-fatigue interaction near instability. Surface crack growth experiments are conducted with Inconel 718 to characterize tearing resistance, FCG under small-scale yielding and elastic-plastic conditions, and crack growth during simulated MCPT. Fractography and acoustic emission studies provide additional insight. The relative merits of SCPT and MCPT are directly compared using a probabilistic analysis linked with an elastic-plastic crack growth computer code. The conditional probability of failure in service is computed for a population of components that have survived a previous proof test, based on an assumed distribution of initial crack depths. Parameter studies investigate the influence of proof factor, tearing resistance, crack shape, initial crack depth distribution, and notches on the MCPT vs. SCPT comparison. The parameter studies provide a rational basis to formulate conclusions about the relative advantages and disadvantages of SCPT and MCPT. Practical engineering guidelines are proposed to help select the optimum proof test protocol in a given application.

  1. High temperature and pressure electrochemical test station

    NASA Astrophysics Data System (ADS)

    Chatzichristodoulou, C.; Allebrod, F.; Mogensen, M.

    2013-05-01

    An electrochemical test station capable of operating at pressures up to 100 bars and temperatures up to 400 °C has been established. It enables control of the partial pressures and mass flow of O2, N2, H2, CO2, and H2O in a single or dual environment arrangement, measurements with highly corrosive media, as well as localized sampling of gas evolved at the electrodes for gas analysis. A number of safety and engineering design challenges have been addressed. Furthermore, we present a series of electrochemical cell holders that have been constructed in order to accommodate different types of cells and facilitate different types of electrochemical measurements. Selected examples of materials and electrochemical cells examined in the test station are provided, ranging from the evaluation of the ionic conductivity of liquid electrolytic solutions immobilized in mesoporous ceramic structures, to the electrochemical characterization of high temperature and pressure alkaline electrolysis cells and the use of pseudo-reference electrodes for the separation of each electrode contribution. A future perspective of various electrochemical processes and devices that can be developed with the use of the established test station is provided.

  2. High temperature and pressure electrochemical test station.

    PubMed

    Chatzichristodoulou, C; Allebrod, F; Mogensen, M

    2013-05-01

    An electrochemical test station capable of operating at pressures up to 100 bars and temperatures up to 400 °C has been established. It enables control of the partial pressures and mass flow of O2, N2, H2, CO2, and H2O in a single or dual environment arrangement, measurements with highly corrosive media, as well as localized sampling of gas evolved at the electrodes for gas analysis. A number of safety and engineering design challenges have been addressed. Furthermore, we present a series of electrochemical cell holders that have been constructed in order to accommodate different types of cells and facilitate different types of electrochemical measurements. Selected examples of materials and electrochemical cells examined in the test station are provided, ranging from the evaluation of the ionic conductivity of liquid electrolytic solutions immobilized in mesoporous ceramic structures, to the electrochemical characterization of high temperature and pressure alkaline electrolysis cells and the use of pseudo-reference electrodes for the separation of each electrode contribution. A future perspective of various electrochemical processes and devices that can be developed with the use of the established test station is provided. PMID:23742566

  3. 46 CFR 54.05-6 - Toughness test temperatures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Toughness test temperatures. 54.05-6 Section 54.05-6... Toughness Tests § 54.05-6 Toughness test temperatures. Each toughness test must be conducted at temperatures not warmer than −20 °F or 10 °F below the minimum service temperature, whichever is lower, except...

  4. 46 CFR 54.05-6 - Toughness test temperatures.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Toughness test temperatures. 54.05-6 Section 54.05-6... Toughness Tests § 54.05-6 Toughness test temperatures. Each toughness test must be conducted at temperatures not warmer than −20 °F or 10 °F below the minimum service temperature, whichever is lower, except...

  5. 30 CFR 35.20 - Autogenous-ignition temperature test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Autogenous-ignition temperature test. 35.20... Autogenous-ignition temperature test. (a) Purpose. The purpose of this test, referred to hereinafter as the ignition-temperature test, is to determine the lowest autogenous-ignition temperature of a hydraulic...

  6. 30 CFR 35.20 - Autogenous-ignition temperature test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Autogenous-ignition temperature test. 35.20... Autogenous-ignition temperature test. (a) Purpose. The purpose of this test, referred to hereinafter as the ignition-temperature test, is to determine the lowest autogenous-ignition temperature of a hydraulic...

  7. 30 CFR 35.20 - Autogenous-ignition temperature test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Autogenous-ignition temperature test. 35.20... Autogenous-ignition temperature test. (a) Purpose. The purpose of this test, referred to hereinafter as the ignition-temperature test, is to determine the lowest autogenous-ignition temperature of a hydraulic...

  8. 30 CFR 35.20 - Autogenous-ignition temperature test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Autogenous-ignition temperature test. 35.20... Autogenous-ignition temperature test. (a) Purpose. The purpose of this test, referred to hereinafter as the ignition-temperature test, is to determine the lowest autogenous-ignition temperature of a hydraulic...

  9. 46 CFR 54.05-6 - Toughness test temperatures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Toughness test temperatures. 54.05-6 Section 54.05-6... Toughness Tests § 54.05-6 Toughness test temperatures. Each toughness test must be conducted at temperatures not warmer than −20 °F or 10 °F below the minimum service temperature, whichever is lower, except...

  10. 46 CFR 54.05-6 - Toughness test temperatures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Toughness test temperatures. 54.05-6 Section 54.05-6... Toughness Tests § 54.05-6 Toughness test temperatures. Each toughness test must be conducted at temperatures not warmer than −20 °F or 10 °F below the minimum service temperature, whichever is lower, except...

  11. 46 CFR 54.05-6 - Toughness test temperatures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Toughness test temperatures. 54.05-6 Section 54.05-6... Toughness Tests § 54.05-6 Toughness test temperatures. Each toughness test must be conducted at temperatures not warmer than −20 °F or 10 °F below the minimum service temperature, whichever is lower, except...

  12. Regenerable Microbial Check Valve - Life cycle tests results

    NASA Technical Reports Server (NTRS)

    Atwater, James E.; Wheeler, Richard R., Jr.; Olivadoti, J. T.; Sauer, Richard L.; Flanagan, David T.

    1992-01-01

    Life cycle regeneration testing of the Microbial Check Valve (MCV) that is used on the Shuttle Orbiter to provide microbial control of potable water is currently in progress. Four beds are being challenged with simulated reclaimed waters and repeatedly regenerated. Preliminary results indicate that contaminant systems exhibit unique regeneration periodicities. Cyclic throughput diminishes with increasing cumulative flow. It is considered to be feasible to design a regenerable MCV system which will function without human intervention and with minimal resupply penalty for the 30 year life of the Space Station.

  13. A combined power and ejector refrigeration cycle for low temperature heat sources

    SciTech Connect

    Zheng, B.; Weng, Y.W.

    2010-05-15

    A combined power and ejector refrigeration cycle for low temperature heat sources is under investigation in this paper. The proposed cycle combines the organic Rankine cycle and the ejector refrigeration cycle. The ejector is driven by the exhausts from the turbine to produce power and refrigeration simultaneously. A simulation was carried out to analyze the cycle performance using R245fa as the working fluid. A thermal efficiency of 34.1%, an effective efficiency of 18.7% and an exergy efficiency of 56.8% can be obtained at a generating temperature of 395 K, a condensing temperature of 298 K and an evaporating temperature of 280 K. Simulation results show that the proposed cycle has a big potential to produce refrigeration and most exergy losses take place in the ejector. (author)

  14. On massive carbide precipitation during high temperature low cycle fatigue in alloy 800H

    SciTech Connect

    Bhanu Sankara Rao, K.; Halford, G.R. . Lewis Research Center); Schuster, H. . Inst. for Reactor Materials)

    1994-08-15

    Alloys engineered for high-temperature application are frequently put into use in a thermodynamically unstable condition. Subsequent exposure to service temperatures may promote many thermally-assisted reactions such as formation, coarsening, and/or coalescence of precipitates. Superposition of cyclic straining may accelerate the kinetics of these reactions but also may cause reaction products having specific features not observed under simple thermal exposure. The influence of cyclic strain-induced microstructural changes on the fatigue behavior has to be considered in terms of their effects on both cyclic strength and life. The occurrence of massive (cellular) precipitation of M[sub 23]C[sub 6] on grain boundaries during elevated temperature low cycle fatigue testing has been reported in Type 304 stainless steel, Type 316 stainless steel, and Inconel 617 superalloy, and its presence has already been linked with reduction in high temperature ductility, an important engineering property on which low cycle fatigue (LCF) life depends to a large extent. Massive precipitation may render the austenitic engineering alloys susceptible to corrosion, which would have important bearing on the performance of these alloys in the oxidizing environments. Furthermore, the long term stability of massive M[sub 23]C[sub 6] particles is particularly important since the transformation of such a large structure into a brittle intermetallic phase (such as sigma) could produce a detrimental effect on the mechanical properties. The conditions and the mechanisms responsible for the occurrence of massive precipitation during LCF have not yet been established. This investigation is specifically aimed at understanding the influence of strain rate on massive precipitation and the mechanism responsible for the occurrence of massive M[sub 23]C[sub 6] precipitation in Alloy 800H during elevated temperature LCF testing.

  15. Life cycle test results of a bipolar nickel hydrogen battery

    NASA Technical Reports Server (NTRS)

    Cataldo, R. L.

    1985-01-01

    A history is given of low Earth orbit (LEO) laboratory test data on a 6.5 ampere-hour bipolar nickel hydrogen battery designed and built at the NASA Lewis Research Center. The bipolar concept is a means of achieving the goal of producing an acceptable battery, of higher energy density, able to withstand the demands of low-Earth-orbit regimes. Over 4100 LEO cycles were established on a ten cell battery. It seems that any perturbation on normal cycling effects the cells performance. Explanations and theories of the battery's behavior are varied and widespread among those closely associated with it. Deep discharging does provide a reconditioning effect and further experimentation is planned in this area. The battery watt-hour efficiency is about 75 percent and the time averaged, discharge voltage is about 1.26 volts for all cells at both the C/4 and LEO rate. Since a significant portion of the electrode capacity has degraded, the LEO cycle discharges are approaching depths of 90 to 100 percent of the high rate capacity. Therefore, the low end-of-discharge voltages occur precipitously after the knee of the discharge curve and is more an indication of electrode capacity and is a lesser indicator of overall cell performance.

  16. Advanced Low Temperature Geothermal Power Cycles (The ENTIV Organic Project) Final Report

    SciTech Connect

    Mugerwa, Michael

    2015-11-18

    Feasibility study of advanced low temperature thermal power cycles for the Entiv Organic Project. Study evaluates amonia-water mixed working fluid energy conversion processes developed and licensed under Kalex in comparison with Kalina cycles. Both cycles are developed using low temperature thermal resource from the Lower Klamath Lake Geothermal Area. An economic feasibility evaluation was conducted for a pilot plant which was deemed unfeasible by the Project Sponsor (Entiv).

  17. Results of the integrated topping cycle MHD generator testing

    SciTech Connect

    Pian, C.C.P.; Schmitt, E.W.

    1994-12-31

    The results of the Integrated Topping Cycle (ITC) MHD generator tests are presented. This generator is part of a 50 MW{sub t} prototypic powertrain which recently completed proof-of-concept (POC) testing at the U.S. Department of Energy`s Component Development and Integration Facility (CDIF) in Butte, Montana. POC duration testing was carried out at conditions representative of commercial power plant operation, in order to establish component lifetimes and to verify the design performance parameters. Over 500 hours of thermal and power testing was cumulated with the generator hardware before the program funding was terminated. A summary of the MHD generator performance characteristics and hardware evaluations is provided in the paper. A summary of the generator performance throughout the POC test series is presented. Included are comparisons of: (1) plasma electrical conductivities measured early in the Design Verification Test series and during the POC series, (2) measured generator performance with analytical predictions, and (3) internal wall leakage characteristics of the generator channel with and without iron oxide addition. The performance requirement of the ITC program, i.e., the demonstration of 1.5 MW{sub e} power output, was easily achieved. The ITC generator channel, nozzle, and diffuser accumulated more than 300 hours at nominal power conditions. The prototypic hardware performed well throughout the POC test series. Some problems did arise during the tests. but they were not life-threatening to the MHD generator. Corrective measures were implemented; they will be discussed in the full paper. The physical condition of the overall generator channel at the end of POC tests is good.

  18. 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.

  19. High Temperature Fluoride Salt Test Loop

    SciTech Connect

    Aaron, Adam M.; Cunningham, Richard Burns; Fugate, David L.; Holcomb, David Eugene; Kisner, Roger A.; Peretz, Fred J.; Robb, Kevin R.; Wilson, Dane F.; Yoder, Jr, Graydon L.

    2015-12-01

    with 3 cm diameter graphite-based fuel pebbles slowly circulating up through the core. Molten salt coolant (FLiBe) at 700°C flows concurrently (at significantly higher velocity) with the pebbles and is used to remove heat generated in the reactor core (approximately 1280 W/pebble), and supply it to a power conversion system. Refueling equipment continuously sorts spent fuel pebbles and replaces spent or damaged pebbles with fresh fuel. By combining greater or fewer numbers of pebble channel assemblies, multiple reactor designs with varying power levels can be offered. The PB-AHTR design is discussed in detail in Reference [1] and is shown schematically in Fig. 1. Fig. 1. PB-AHTR concept (drawing taken from Peterson et al., Design and Development of the Modular PB-AHTR Proceedings of ICApp 08). Pebble behavior within the core is a key issue in proving the viability of this concept. This includes understanding the behavior of the pebbles thermally, hydraulically, and mechanically (quantifying pebble wear characteristics, flow channel wear, etc). The experiment being developed is an initial step in characterizing the pebble behavior under realistic PB-AHTR operating conditions. It focuses on thermal and hydraulic behavior of a static pebble bed using a convective salt loop to provide prototypic fluid conditions to the bed, and a unique inductive heating technique to provide prototypic heating in the pebbles. The facility design is sufficiently versatile to allow a variety of other experimentation to be performed in the future. The facility can accommodate testing of scaled reactor components or sub-components such as flow diodes, salt-to-salt heat exchangers, and improved pump designs as well as testing of refueling equipment, high temperature instrumentation, and other reactor core designs.

  20. Laser High-Cycle Thermal Fatigue of Pulse Detonation Engine Combustor Materials Tested

    NASA Technical Reports Server (NTRS)

    Zhu, Dong-Ming; Fox, Dennis S.; Miller, Robert A.

    2001-01-01

    Pulse detonation engines (PDE's) have received increasing attention for future aerospace propulsion applications. Because the PDE is designed for a high-frequency, intermittent detonation combustion process, extremely high gas temperatures and pressures can be realized under the nearly constant-volume combustion environment. The PDE's can potentially achieve higher thermodynamic cycle efficiency and thrust density in comparison to traditional constant-pressure combustion gas turbine engines (ref. 1). However, the development of these engines requires robust design of the engine components that must endure harsh detonation environments. In particular, the detonation combustor chamber, which is designed to sustain and confine the detonation combustion process, will experience high pressure and temperature pulses with very short durations (refs. 2 and 3). Therefore, it is of great importance to evaluate PDE combustor materials and components under simulated engine temperatures and stress conditions in the laboratory. In this study, a high-cycle thermal fatigue test rig was established at the NASA Glenn Research Center using a 1.5-kW CO2 laser. The high-power laser, operating in the pulsed mode, can be controlled at various pulse energy levels and waveform distributions. The enhanced laser pulses can be used to mimic the time-dependent temperature and pressure waves encountered in a pulsed detonation engine. Under the enhanced laser pulse condition, a maximum 7.5-kW peak power with a duration of approximately 0.1 to 0.2 msec (a spike) can be achieved, followed by a plateau region that has about one-fifth of the maximum power level with several milliseconds duration. The laser thermal fatigue rig has also been developed to adopt flat and rotating tubular specimen configurations for the simulated engine tests. More sophisticated laser optic systems can be used to simulate the spatial distributions of the temperature and shock waves in the engine. Pulse laser high-cycle

  1. 30 CFR 7.47 - Deflection temperature test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Deflection temperature test. 7.47 Section 7.47... temperature test. (a) Test procedures. (1) Prepare two samples for testing that measure 5 inches by 1/2 inch... which are 4 inches apart and immersed in a heat transfer medium at a test temperature range of 65...

  2. Thermal analysis of heat and power plant with high temperature reactor and intermediate steam cycle

    NASA Astrophysics Data System (ADS)

    Fic, Adam; Składzień, Jan; Gabriel, Michał

    2015-03-01

    Thermal analysis of a heat and power plant with a high temperature gas cooled nuclear reactor is presented. The main aim of the considered system is to supply a technological process with the heat at suitably high temperature level. The considered unit is also used to produce electricity. The high temperature helium cooled nuclear reactor is the primary heat source in the system, which consists of: the reactor cooling cycle, the steam cycle and the gas heat pump cycle. Helium used as a carrier in the first cycle (classic Brayton cycle), which includes the reactor, delivers heat in a steam generator to produce superheated steam with required parameters of the intermediate cycle. The intermediate cycle is provided to transport energy from the reactor installation to the process installation requiring a high temperature heat. The distance between reactor and the process installation is assumed short and negligable, or alternatively equal to 1 km in the analysis. The system is also equipped with a high temperature argon heat pump to obtain the temperature level of a heat carrier required by a high temperature process. Thus, the steam of the intermediate cycle supplies a lower heat exchanger of the heat pump, a process heat exchanger at the medium temperature level and a classical steam turbine system (Rankine cycle). The main purpose of the research was to evaluate the effectiveness of the system considered and to assess whether such a three cycle cogeneration system is reasonable. Multivariant calculations have been carried out employing the developed mathematical model. The results have been presented in a form of the energy efficiency and exergy efficiency of the system as a function of the temperature drop in the high temperature process heat exchanger and the reactor pressure.

  3. 40 CFR Appendix E to Subpart S of... - Transient Test Driving Cycle

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 2 2011-07-01 2011-07-01 false Transient Test Driving Cycle E Appendix... Driving Cycle (I) Driver's trace. All excursions in the transient driving cycle shall be evaluated by the... shall cause a test to be void. In addition, provisions shall be available to utilize cycle...

  4. 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.

  5. Thermal Cycle Testing of the Powersphere Engineering Development Unit

    NASA Technical Reports Server (NTRS)

    Curtis, Henry; Piszczor, Mike; Kerslake, Thomas W.; Peterson, Todd T.; Scheiman, David A.; Simburger, Edward J.; Giants, Thomas W.; Matsumoto, James H.; Garcia, Alexander; Liu, Simon H.; Lin, John K.; Scarborough, Stephen E.; Gleeson, Daniel J.; Rawal, Suraj P.; Perry, Alan R.; Marshall, Craig H.

    2007-01-01

    During the past three years the team of The Aerospace Corporation, Lockheed Martin Space Systems, NASA Glenn Research Center, and ILC Dover LP have been developing a multifunctional inflatable structure for the PowerSphere concept under contract with NASA (NAS3-01115). The PowerSphere attitude insensitive solar power-generating microsatellite, which could be used for many different space and Earth science purposes, is ready for further refinement and flight demonstration. The development of micro- and nanosatellites requires the energy collection system, namely the solar array, to be of lightweight and small size. The limited surface area of these satellites precludes the possibility of body mounting the solar array system for required power generation. The use of large traditional solar arrays requires the support of large satellite volumes and weight and also requires a pointing apparatus. The current PowerSphere concept (geodetic sphere), which was envisioned in the late 1990 s by Mr. Simburger of The Aerospace Corporation, has been systematically developed in the past several years.1-7 The PowerSphere system is a low mass and low volume system suited for micro and nanosatellites. It is a lightweight solar array that is spherical in shape and does not require a pointing apparatus. The recently completed project culminated during the third year with the manufacturing of the PowerSphere Engineering Development Unit (EDU). One hemisphere of the EDU system was tested for packing and deployment and was subsequently rigidized. The other hemisphere was packed and stored for future testing in an uncured state. Both cured and uncured hemisphere components were delivered to NASA Glenn Research Center for thermal cycle testing and long-term storage respectively. This paper will discuss the design, thermal cycle testing of the PowerSphere EDU.

  6. Automatic 300-4 K temperature cycling apparatus.

    PubMed

    Hamilton, C A

    1978-05-01

    The apparatus described here automatically cycles small samples between 300 and 4 K by alternately raising and lowering the sample through the neck of a commercial liquid helium storage Dewar. A bellows, which is pressurized by the helium boil-off gas, provides all of the required mechanical motion. By utilizing the cooling available from the boil-off gas, liquid helium helium consumption is limited to 0.03 l/cyc for a 12-g sample. Cycle times can be as short as 5 min. PMID:18699173

  7. Scale Resistant Heat Exchanger for Low Temperature Geothermal Binary Cycle Power Plant

    SciTech Connect

    Hays, Lance G.

    2014-11-18

    Phase 1 of the investigation of improvements to low temperature geothermal power systems was completed. The improvements considered were reduction of scaling in heat exchangers and a hermetic turbine generator (eliminating seals, seal system, gearbox, and lube oil system). A scaling test system with several experiments was designed and operated at Coso geothermal resource with brine having a high scaling potential. Several methods were investigated at the brine temperature of 235 ºF. One method, circulation of abradable balls through the brine passages, was found to substantially reduce scale deposits. The test heat exchanger was operated with brine outlet temperatures as low as 125 ºF, which enables increased heat input available to power conversion systems. For advanced low temperature cycles, such as the Variable Phase Cycle (VPC) or Kalina Cycle, the lower brine temperature will result in a 20-30% increase in power production from low temperature resources. A preliminary design of an abradable ball system (ABS) was done for the heat exchanger of the 1 megawatt VPC system at Coso resource. The ABS will be installed and demonstrated in Phase 2 of this project, increasing the power production above that possible with the present 175 ºF brine outlet limit. A hermetic turbine generator (TGH) was designed and manufacturing drawings produced. This unit will use the working fluid (R134a) to lubricate the bearings and cool the generator. The 200 kW turbine directly drives the generator, eliminating a gearbox and lube oil system. Elimination of external seals eliminates the potential of leakage of the refrigerant or hydrocarbon working fluids, resulting in environmental improvement. A similar design has been demonstrated by Energent in an ORC waste heat recovery system. The existing VPC power plant at Coso was modified to enable the “piggyback” demonstration of the TGH. The existing heat exchanger, pumps, and condenser will be operated to provide the required

  8. Performance evaluation of a low-temperature solar Rankine cycle system utilizing R245fa

    SciTech Connect

    Wang, X.D.; Zhao, L.; Wang, J.L.; Zhang, W.Z.; Zhao, X.Z.; Wu, W.

    2010-03-15

    A low-temperature solar Rankine system utilizing R245fa as the working fluid is proposed and an experimental system is designed, constructed and tested. Both the evacuated solar collectors and the flat plate solar collectors are used in the experimental system; meanwhile, a rolling-piston R245fa expander is also mounted in the system. The new designed R245fa expander works stably in the experiment, with an average expansion power output of 1.73 kW and an average isentropic efficiency of 45.2%. The overall power generation efficiency estimated is 4.2%, when the evacuated solar collector is utilized in the system, and with the condition of flat plate solar collector, it is about 3.2%. The experimental results show that using R245fa as working fluid in the low-temperature solar power Rankine cycle system is feasible and the performance is acceptable. (author)

  9. Mutagenicity of diesel exhaust particle extracts: influence of driving cycle and environmental temperature.

    PubMed

    Clark, C R; Dutcher, J S; Brooks, A L; McClellan, R O; Marshall, W F; Naman, T M

    1982-01-01

    General Motors and Volkswagen diesel passenger cars (1980 and 1981 model year) were operated on a climate controlled chassis dynomometer and the particulate portion of the exhaust was collected on high volume filters. Dichloromethane extracts of the exhaust particles (soot) collected while the cars were operated under simulated highway, urban and congested urban driving cycles were assayed for mutagenicity in Salmonella strains TA-98 and TA-100. Driving pattern did not significantly influence the mutagenic potency of the exhaust particle extracts or estimates of the amount of mutagenicity emitted from the exhaust despite large differences in particle emission rates and extractable fraction of the particles. Mutagenicity of extracts of exhaust particles collected while the vehicles were operated at test chamber temperatures of 25, 50, 75 and 100 degrees F were also very similar. The results suggest that driving pattern and environmental temperature do not significantly alter the emission of genotoxic combustion products from the exhaust. PMID:6193022

  10. Thermal Cycling Reliability of Sn-Ag-Cu Solder Interconnections. Part 1: Effects of Test Parameters

    NASA Astrophysics Data System (ADS)

    Hokka, Jussi; Mattila, Toni. T.; Xu, Hongbo; Paulasto-Kröckel, Mervi

    2013-06-01

    The work presented in part 1 of this study focuses on identifying the effects of thermal cycling test parameters on the lifetime of ball grid array (BGA) component boards. Detailed understanding about the effects of the thermal cycling parameters is essential because it provides means to develop more efficient and meaningful methods of reliability assessment for electronic products. The study was carried out with a single package type (BGA with 144 solder balls), printed wiring board (eight-layer build-up FR4 structure), and solder interconnection composition (Sn-3.1Ag-0.5Cu) to ensure that individual test results would be comparable with each other. The effects of (i) temperature difference (Δ T), (ii) lower dwell temperature and lower dwell time, (iii) mean temperature, (iv) dwell time, and (v) ramp rate were evaluated. Based on the characteristic lifetimes, the thermal cycling profiles were categorized into three lifetime groups: (i) highly accelerated conditions, (ii) moderately accelerated conditions, and (iii) mildly/nonaccelerated conditions. Thus, one might be tempted to use the highly accelerated conditions to produce lifetime statistics as quickly as possible. However, to do this one needs to know that the failure mechanisms do not change from one lifetime group to another and that the failure mechanisms correlate with real-use failures. Therefore, in part 2 the observed differences in component board lifetimes will be explained by studying the failure mechanisms that take place in the three lifetime groups.

  11. Temperature Cycles Induce Early Maturation in Channel Catfish

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A major impediment in improvement of channel catfish by selective breeding is that a high percent of fish do not spawn until the third year. The conditions that lead to sexual maturation in fish have not been established. Size, nutritional state and number of seasonal cycles have all been suggeste...

  12. Definition study of a Variable Cycle Experimental Engine (VCEE) and associated test program and test plan

    NASA Technical Reports Server (NTRS)

    Allan, R. D.

    1978-01-01

    The Definition Study of a Variable Cycle Experimental Engine (VCEE) and Associated Test Program and Test Plan, was initiated to identify the most cost effective program for a follow-on to the AST Test Bed Program. The VCEE Study defined various subscale VCE's based on different available core engine components, and a full scale VCEE utilizing current technology. The cycles were selected, preliminary design accomplished and program plans and engineering costs developed for several program options. In addition to the VCEE program plans and options, a limited effort was applied to identifying programs that could logically be accomplished on the AST Test Bed Program VCE to extend the usefulness of this test hardware. Component programs were provided that could be accomplished prior to the start of a VCEE program.

  13. Cycle simulation of the low-temperature triple-effect absorption chiller with vapor compression unit

    SciTech Connect

    Kim, J.S.; Lee, H.

    1999-07-01

    The construction of a triple-effect absorption chiller machine using the lithium bromide-water solution as a working fluid is strongly limited by corrosion problems caused by the high generator temperature. In this work, three new cycles having the additional vapor compression units were suggested in order to lower the generator temperature of a triple-effect absorption chiller. Each new cycle has one compressor located at the different position which was used to elevate the pressure of the refrigerant vapor. Computer simulations were carried out in order to examine both the basic triple-effect cycle and three new cycles. All types of triple-effect absorption chiller cycles were found to be able to lower the temperature of high-temperature generator to the more favorable operation range. The COPs of three cycles calculated by considering the additional compressor works showed a small level of decrease or increase compared with that of the basic triple-effect cycle. Consequently, a low-temperature triple-effect absorption chiller can be possibly constructed by adapting one of three new cycles. A great advantage of these new cycles over the basic one is that the conventionally used lithium bromide-water solution can be successfully used as a working fluid without the danger of corrosion.

  14. Hybrid sulfur cycle operation for high-temperature gas-cooled reactors

    SciTech Connect

    Gorensek, Maximilian B

    2015-02-17

    A hybrid sulfur (HyS) cycle process for the production of hydrogen is provided. The process uses a proton exchange membrane (PEM) SO.sub.2-depolarized electrolyzer (SDE) for the low-temperature, electrochemical reaction step and a bayonet reactor for the high-temperature decomposition step The process can be operated at lower temperature and pressure ranges while still providing an overall energy efficient cycle process.

  15. High temperature pressurized high frequency testing rig and test method

    DOEpatents

    De La Cruz, Jose; Lacey, Paul

    2003-04-15

    An apparatus is described which permits the lubricity of fuel compositions at or near temperatures and pressures experienced by compression ignition fuel injector components during operation in a running engine. The apparatus consists of means to apply a measured force between two surfaces and oscillate them at high frequency while wetted with a sample of the fuel composition heated to an operator selected temperature. Provision is made to permit operation at or near the flash point of the fuel compositions. Additionally a method of using the subject apparatus to simulate ASTM Testing Method D6079 is disclosed, said method involving using the disclosed apparatus to contact the faces of prepared workpieces under a measured load, sealing the workface contact point into the disclosed apparatus while immersing said contact point between said workfaces in a lubricating media to be tested, pressurizing and heating the chamber and thereby the fluid and workfaces therewithin, using the disclosed apparatus to impart a differential linear motion between the workpieces at their contact point until a measurable scar is imparted to at least one workpiece workface, and then evaluating the workface scar.

  16. 33 CFR 159.119 - Operability test; temperature range.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Operability test; temperature... Operability test; temperature range. The device must operate in an ambient temperature of 5 °C with inlet operating fluid temperature varying from 2 °C to 32 °C and in an ambient temperature of 50 °C with...

  17. 33 CFR 159.119 - Operability test; temperature range.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Operability test; temperature... Operability test; temperature range. The device must operate in an ambient temperature of 5 °C with inlet operating fluid temperature varying from 2 °C to 32 °C and in an ambient temperature of 50 °C with...

  18. 33 CFR 159.119 - Operability test; temperature range.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Operability test; temperature... Operability test; temperature range. The device must operate in an ambient temperature of 5 °C with inlet operating fluid temperature varying from 2 °C to 32 °C and in an ambient temperature of 50 °C with...

  19. 33 CFR 159.119 - Operability test; temperature range.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Operability test; temperature... Operability test; temperature range. The device must operate in an ambient temperature of 5 °C with inlet operating fluid temperature varying from 2 °C to 32 °C and in an ambient temperature of 50 °C with...

  20. Effects of temperature and organic pollution on nutrient cycling in marine sediments

    NASA Astrophysics Data System (ADS)

    Sanz-Lazaro, C.; Valdemarsen, T.; Holmer, M.

    2015-08-01

    Increasing ocean temperature due to climate change is an important anthropogenic driver of ecological change in coastal systems. In these systems sediments play a major role in nutrient cycling. Our ability to predict ecological consequences of climate change is enhanced by simulating real scenarios. Based on predicted climate change scenarios, we tested the effect of temperature and organic pollution on nutrient release from coastal sediments to the water column in a mesocosm experiment. PO43- release rates from sediments followed the same trends as organic matter mineralization rates, increased linearly with temperature and were significantly higher under organic pollution than under nonpolluted conditions. NH4+ release only increased significantly when the temperature rise was above 6 °C, and it was significantly higher in organic polluted compared to nonpolluted sediments. Nutrient release to the water column was only a fraction from the mineralized organic matter, suggesting PO43- retention and NH4+ oxidation in the sediment. Bioturbation and bioirrigation appeared to be key processes responsible for this behavior. Considering that the primary production of most marine basins is N-limited, the excess release of NH4+ at a temperature rise > 6 °C could enhance water column primary productivity, which may lead to the deterioration of the environmental quality. Climate change effects are expected to be accelerated in areas affected by organic pollution.

  1. Influence of temperature, environment, and thermal aging on the continuous cycle fatigue behavior of Hastelloy X and Inconel 617

    SciTech Connect

    Strizak, J.P.; Brinkman, C.R.; Booker, M.K.; Rittenhouse, P.L.

    1982-04-01

    Results are presented for strain-controlled fatigue and tensile tests for two nickel-base, solution-hardened reference structural alloys for use in several High-Temperature Gas-Cooled Reactor (HTGR) concepts. These alloys, Hastelloy X and Inconel 617, were tested from room temperature to 871/sup 0/C in air and impure helium. Materials were tested in both the solution-annealed and the preaged conditios, in which aging consisted of isothermal exposure at one of several temperatures for periods of up to 20,000 h. Comparisons are given between the strain-controlled fatigue lives of these and several other commonly used alloys, all tested at 538/sup 0/C. An analysis is also presented of the continuous cycle fatigue data obtained from room temperature to 427/sup 0/C for Hastelloy G, Hastelloy X, Hastelloy C-276, and Hastelloy C-4, an effort undertaken in support of ASME code development.

  2. MAVRIC Flutter Model Transonic Limit Cycle Oscillation Test

    NASA Technical Reports Server (NTRS)

    Edwards, John W.; Schuster, David M.; Spain, Charles V.; Keller, Donald F.; Moses, Robert W.

    2001-01-01

    The Models for Aeroelastic Validation Research Involving Computation semi-span wind-tunnel model (MAVRIC-I), a business jet wing-fuselage flutter model, was tested in NASA Langley's Transonic Dynamics Tunnel with the goal of obtaining experimental data suitable for Computational Aeroelasticity code validation at transonic separation onset conditions. This research model is notable for its inexpensive construction and instrumentation installation procedures. Unsteady pressures and wing responses were obtained for three wingtip configurations of clean, tipstore, and winglet. Traditional flutter boundaries were measured over the range of M = 0.6 to 0.9 and maps of Limit Cycle Oscillation (LCO) behavior were made in the range of M = 0.85 to 0.95. Effects of dynamic pressure and angle-of-attack were measured. Testing in both R134a heavy gas and air provided unique data on Reynolds number, transition effects, and the effect of speed of sound on LCO behavior. The data set provides excellent code validation test cases for the important class of flow conditions involving shock-induced transonic flow separation onset at low wing angles, including LCO behavior.

  3. Conventional and Advanced Silicagel-water Adsorption Cycles Driven by Near - environmental Temperature Heat

    NASA Astrophysics Data System (ADS)

    Boelman, Elisa; B. Saha, Bidyut; Tanaka, Aiharu; Kashiwagi, Takao

    This work aims at clarifying the possible operating temperature ranges for silica gel-water adsorption refrigeration cycles driven by near-environmental temperature heat sources (between 50°C and 85°C), with relatively small regenerating temperature lifts (10 K to 65 K). A newly developed three stage advanced silica gel-water cycle, which is operational with 50°C driving heat source and 30°C cooling source is introduced and compared with a conventional single stage cycle. The cycles are evaluated in terms of cooling capacity, COP and the viability of operation with near-environmental temperature driving heat sources. The analysis is based on experimental and cycle simulation work. The results showed the advanced three stage cycle to be particularly suited for operation with low grade waste heat driving sources, since it worked with small regenerating temperature lifts (ΔTregen)of 10K to 30K. Another significant advantage of operation with small ΔTregen is the possibility to reduce irreversible heat losses from batched cycle operation. Experiments carried out on full-size machine suggested that, even with smallΔTregen, adsorber /desorber heat exchanger improvements such as higher thermal conductance and smaller heat capacitance can contribute to reduce heat losses while improving cycle performance in terms of cooling capacity and COP.

  4. Effect of Upper-Cycle Temperature on the Load-Biased, Strain-Temperature Response of NiTi

    NASA Technical Reports Server (NTRS)

    Padula, Santo, II; Noebe, Ronald; Bigelow, Glen; Qiu, Shipeng; Vaidyanathan, Raj; Gaydosh, Darrell; Garg, Anita

    2011-01-01

    Over the past decade, interest in shape memory alloy based actuators has increased as the primary benefits of these solid-state devices have become more apparent. However, much is still unknown about the characteristic behavior of these materials when used in actuator applications. Recently we have shown that the maximum temperature reached during thermal cycling under isobaric conditions could significantly affect the observed mechanical response of NiTi (55 wt% Ni), especially the amount of transformation strain available for actuation and thus work output. The investigation we report here extends that original work to ascertain whether further increases in the upper-cycle temperature would produce additional changes in the work output of the material, which has a stress-free austenite finish temperature of 113 C, and to determine the optimum cyclic conditions. Thus, isobaric, thermal-cycle experiments were conducted on the aforementioned alloy at various stresses from 50-300 MPa using upper-cycle temperatures of 165, 200, 230, 260, 290, 320 and 350 C. The data indicated that the amount of applied stress influenced the transformation strain, as would be expected. However, the maximum temperature reached during the thermal excursion also plays an equally significant role in determining the transformation strain, with the maximum transformation strain observed during thermal cycling to 290 C. In situ neutron diffraction at stress and temperature showed that the differences in transformation strain were mostly related to changes in martensite texture when cycling to different upper-cycle temperatures. Hence, understanding this effect is important to optimizing the operation of SMA-based actuators and could lead to new methods for processing and training shape memory alloys for optimal performance.

  5. High temperature erosion testing in a gasifier environment

    SciTech Connect

    Tylczak, Joseph H.; Rawers, James C.; Adler, Thomas A.

    2004-01-01

    The development of materials with the ability to operate in adverse conditions while resisting the effects of erosion and corrosion is essential to the future success of high efficiency power plants. Many next generation coal power plants are envisioned as combined cycle, with gasifiers used to produce both steam and syngas. The gasifier sections of these plants require materials of construction that are resistant to the effects of erosion from silica found in the gas streams and corrosion caused by a reducing atmosphere that may contain sulfur and chloride compounds. The Albany Research Center has developed a test apparatus designed to test the erosion-resistance of candidate materials under a range of environmental conditions, including those found in gasifiers. This Hostile Atmosphere Erosion Wear test apparatus (HAET) has been used to evaluate a group of high alloy candidate materials such as iron aluminide and Haynes HR 160, and compare them to a conventional 310 stainless steel. Erosion tests were conducted using 270μm silica abrasive, a typical impact velocities of 20 m/sec at temperatures up to 700°C in an atmosphere simulating gasifier conditions. The effects of erosion under these conditions on the surface scales that form are described. The total loss rate, loss rates due to erosion and corrosion for the test materials are compared.

  6. Pressure cycle rheology of nanofluids at ambient temperature

    NASA Astrophysics Data System (ADS)

    Kanjirakat, Anoop; Sadr, Reza; Yrac, Rommel; Amani, Mahmood

    2015-11-01

    Colloidal suspensions of particles dispersed in a base fluid (or drilling fluid) are commonly used in oil industry to aid the drilling of oil well into the ground. Nanofluids, the colloidal suspensions of nano-sized particles dispersed in a basefluid, have also shown potentials as cooling and abrasive fluids. Utilizing them along with drilling fluids under cyclic high-pressure loadings have not been investigated so far. In the present work, rheological characteristics of silicon oil based nanofluids (prepared with alumina nanoparticles) under pressures up to 1000 bar are investigated using a high-pressure viscometer. The rheological characteristics of nanofluids are measured and are compared with that of the basefluid under increasing and decreasing pressures. Relative viscosity variations of nanofluids were observed to have influenced by the shear rate. In addition, under cyclic high-pressure loading viscosity values of nanofluids are observed to have reduced. This reduction in viscosity at the second pressure cycle could have been caused by the de-agglomeration of particles in the first cycle while working a high-pressure and high-shear condition.

  7. Where can we find a seasonal cycle of the Atlantic water temperature within the Arctic Basin?

    NASA Astrophysics Data System (ADS)

    Lique, Camille; Steele, Michael

    2012-03-01

    Recent mooring observations in the Arctic Basin suggest the existence of a seasonality of Atlantic Water (AW) temperature. Here the DRAKKAR global ocean/sea-ice model is used to examine the seasonal cycle amplitude of AW temperature within the Arctic Ocean and to investigate the possible mechanisms governing this seasonality. The simulation as well as available mooring data reveals that the amplitude of the AW temperature seasonal cycle is significant only in the Nansen Basin along the continental slope, where AW is primarily advected. In the model, the seasonal cycle of the AW temperature is advected from Fram Strait up to St. Anna Trough and then re-energized by the Barents Sea Branch. This suggests that the seasonal AW temperature signal survives over a finite distance (˜1000 km). Interannual changes in the seasonal cycle amplitude can be as large as the mean seasonal cycle amplitude; thus seasonality is difficult to characterize from observations spanning only a short period. The seasonal bias of in-situ observations taken during spring and summer does not induce a large error when considering the interannual-to-decadal variations of AW temperature, because the seasonal cycle accounts for a small or negligible part of AW temperature variability, even near the inflow region.

  8. 30 CFR 35.20 - Autogenous-ignition temperature test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., EVALUATION, AND APPROVAL OF MINING PRODUCTS FIRE-RESISTANT HYDRAULIC FLUIDS Test Requirements § 35.20... ignition-temperature test, is to determine the lowest autogenous-ignition temperature of a hydraulic...

  9. Actual Versus Predicted Cardiovascular Demands in Submaximal Cycle Ergometer Testing

    PubMed Central

    HOEHN, AMANDA M.; MULLENBACH, MEGAN J.; FOUNTAINE, CHARLES J.

    2015-01-01

    The Astrand-Rhyming cycle ergometer test (ARCET) is a commonly administered submaximal test for estimating aerobic capacity. Whereas typically utilized in clinical populations, the validity of the ARCET to predict VO2max in a non-clinical population, especially female, is less clear. Therefore, the purpose of this study was to determine the accuracy of the ARCET in a sample of healthy and physically active college students. Subjects (13 females, 10 males) performed a maximal cycle ergometer test to volitional exhaustion to determine VO2max. At least 48 hours later, subjects performed the ARCET protocol. Predicted VO2max was calculated following the ARCET format using the age corrected factor. There was no significant difference (p=.045) between actual (41.0±7.97 ml/kg/min) and predicted VO2max (40.3±7.58 ml/kg/min). When split for gender there was a significant difference between actual and predicted VO2 for males, (45.1±7.74 vs. 42.7±8.26 ml/kg/min, p=0.029) but no significant difference observed for females, (37.9±6.9 vs. 38.5±6.77 ml/kg/min, p=0.675). The correlation between actual and predicted VO2 was r=0.84, p<0.001 with an SEE= 4.3 ml/kg/min. When split for gender, the correlation for males was r=0.94, p<0.001, SEE=2.72 ml/kg/min; for females, r=0.74, p=0.004, SEE=4.67 ml/kg/min. The results of this study indicate that the ARCET accurately estimated VO2max in a healthy college population of both male and female subjects. Implications of this study suggest the ARCET can be used to assess aerobic capacity in both fitness and clinical settings where measurement via open-circuit spirometry is either unavailable or impractical. PMID:27182410

  10. Water Power Calculator Temperature and Analog Input/Output Module Ambient Temperature Testing

    SciTech Connect

    Mark D. McKay

    2011-02-01

    Water Power Calculator Temperature and Analog input/output Module Ambient Temperature Testing A series of three ambient temperature tests were conducted for the Water Power Calculator development using the INL Calibration Laboratory’s Tenney Environmental Chamber. The ambient temperature test results demonstrate that the Moore Industries Temperature Input Modules, Analog Input Module and Analog Output Module, ambient temperature response meet or exceed the manufactures specifications

  11. 40 CFR 86.246-94 - Intermediate temperature testing.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) contained in 40 CFR part 86, subpart C. (c) For testing at temperatures of 50 °F (10 °C) or higher, the FTP... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Intermediate temperature testing. 86... New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.246-94...

  12. 30 CFR 7.101 - Surface temperature tests.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Surface temperature tests. 7.101 Section 7.101... temperature tests. The test for determination of exhaust gas cooling efficiency described in § 7.102 may be... the rated horsepower specified in § 7.97(a)(2). (ii) Install sufficient temperature measuring...

  13. 33 CFR 159.115 - Temperature range test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Temperature range test. 159.115...) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.115 Temperature range test. (a) The device must be held at a temperature of 60 °C or higher for a period of 16 hours. (b) The...

  14. 33 CFR 159.115 - Temperature range test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Temperature range test. 159.115...) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.115 Temperature range test. (a) The device must be held at a temperature of 60 °C or higher for a period of 16 hours. (b) The...

  15. 40 CFR 86.246-94 - Intermediate temperature testing.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) contained in 40 CFR part 86, subpart C. (c) For testing at temperatures of 50 °F (10 °C) or higher, the FTP... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Intermediate temperature testing. 86... New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.246-94...

  16. 42 CFR 84.98 - Tests during low temperature operation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Tests during low temperature operation. 84.98...-Contained Breathing Apparatus § 84.98 Tests during low temperature operation. (a) The applicant shall specify the minimum temperature for safe operation and two persons will perform the tests described...

  17. 42 CFR 84.98 - Tests during low temperature operation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Tests during low temperature operation. 84.98...-Contained Breathing Apparatus § 84.98 Tests during low temperature operation. (a) The applicant shall specify the minimum temperature for safe operation and two persons will perform the tests described...

  18. 33 CFR 159.115 - Temperature range test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Temperature range test. 159.115...) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.115 Temperature range test. (a) The device must be held at a temperature of 60 °C or higher for a period of 16 hours. (b) The...

  19. 30 CFR 7.101 - Surface temperature tests.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Surface temperature tests. 7.101 Section 7.101... temperature tests. The test for determination of exhaust gas cooling efficiency described in § 7.102 may be... the rated horsepower specified in § 7.97(a)(2). (ii) Install sufficient temperature measuring...

  20. 33 CFR 159.115 - Temperature range test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Temperature range test. 159.115...) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.115 Temperature range test. (a) The device must be held at a temperature of 60 °C or higher for a period of 16 hours. (b) The...

  1. 42 CFR 84.98 - Tests during low temperature operation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Tests during low temperature operation. 84.98...-Contained Breathing Apparatus § 84.98 Tests during low temperature operation. (a) The applicant shall specify the minimum temperature for safe operation and two persons will perform the tests described...

  2. 30 CFR 7.101 - Surface temperature tests.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Surface temperature tests. 7.101 Section 7.101... temperature tests. The test for determination of exhaust gas cooling efficiency described in § 7.102 may be... the rated horsepower specified in § 7.97(a)(2). (ii) Install sufficient temperature measuring...

  3. 40 CFR 86.246-94 - Intermediate temperature testing.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) contained in 40 CFR part 86, subpart C. (c) For testing at temperatures of 50 °F (10 °C) or higher, the FTP... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Intermediate temperature testing. 86... New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.246-94...

  4. 30 CFR 7.101 - Surface temperature tests.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Surface temperature tests. 7.101 Section 7.101... temperature tests. The test for determination of exhaust gas cooling efficiency described in § 7.102 may be... the rated horsepower specified in § 7.97(a)(2). (ii) Install sufficient temperature measuring...

  5. 40 CFR 86.246-94 - Intermediate temperature testing.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) contained in 40 CFR part 86, subpart C. (c) For testing at temperatures of 50 °F (10 °C) or higher, the FTP... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Intermediate temperature testing. 86... New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.246-94...

  6. 42 CFR 84.98 - Tests during low temperature operation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Tests during low temperature operation. 84.98...-Contained Breathing Apparatus § 84.98 Tests during low temperature operation. (a) The applicant shall specify the minimum temperature for safe operation and two persons will perform the tests described...

  7. 33 CFR 159.115 - Temperature range test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Temperature range test. 159.115...) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.115 Temperature range test. (a) The device must be held at a temperature of 60 °C or higher for a period of 16 hours. (b) The...

  8. 30 CFR 7.101 - Surface temperature tests.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Surface temperature tests. 7.101 Section 7.101... temperature tests. The test for determination of exhaust gas cooling efficiency described in § 7.102 may be... the rated horsepower specified in § 7.97(a)(2). (ii) Install sufficient temperature measuring...

  9. The GISS sounding temperature impact test

    NASA Technical Reports Server (NTRS)

    Halem, M.; Ghil, M.; Atlas, R.; Susskind, J.; Quirk, W. J.

    1978-01-01

    The impact of DST 5 and DST 6 satellite sounding data on mid-range forecasting was studied. The GISS temperature sounding technique, the GISS time-continuous four-dimensional assimilation procedure based on optimal statistical analysis, the GISS forecast model, and the verification techniques developed, including impact on local precipitation forecasts are described. It is found that the impact of sounding data was substantial and beneficial for the winter test period, Jan. 29 - Feb. 21. 1976. Forecasts started from initial state obtained with the aid of satellite data showed a mean improvement of about 4 points in the 48 and 772 hours Sub 1 scores as verified over North America and Europe. This corresponds to an 8 to 12 hour forecast improvement in the forecast range at 48 hours. An automated local precipitation forecast model applied to 128 cities in the United States showed on an average 15% improvement when satellite data was used for numerical forecasts. The improvement was 75% in the midwest.

  10. Effect of Upper-Cycle Temperature on the Load-Biased, Strain-Temperature Response of NiTi

    NASA Technical Reports Server (NTRS)

    Padula, Santo, II; Vaidyanathan, Raj; Gaydosh, Darrell; Noebe, Ronald; Bigelow, Glen; Garg, Anita

    2008-01-01

    Over the past decade, interest in shape memory alloy based actuators has increased as the primary benefits of these solid-state devices have become more apparent. However, much is still unknown about the characteristic behavior of these materials when used in actuator applications. Recently we have shown that the maximum temperature reached during thermal cycling under isobaric conditions could significantly affect the observed mechanical response of NiTi (55 wt% Ni), especially the amount of transformation strain available for actuation and thus work output. This investigation extends that original work to ascertain whether further increases in the upper-cycle temperature would produce additional improvement in the work output of the material, which has a stress-free Af of 113 oC, and to determine the optimum cyclic conditions. Thus, isobaric, thermal-cycle experiments were conducted in the aforementioned alloy at various stress levels from 50-300 MPa using upper-cycle temperatures of 165, 200, 230, 260, 290, 320 and 350 oC. The data indicated that the amount of applied stress influenced the transformation strain available in the system, as would be expected. However, the maximum temperature reached during the thermal excursion also plays a role in determining the transformation strain, with the maximum transformation strain being developed by thermal cycling to 290 oC. In situ, neutron diffraction showed that the differences in transformation strain were related to differences in martensite texture within the microstructure when cycling to different upper-cycle temperatures. Hence, understanding this effect is important to optimizing the operation of SMA-based actuators and could lead to new methods for processing and training shape memory alloys for optimal performance.

  11. Laurentide Ice Sheet basal temperatures at the Last Glacial Cycle as inferred from borehole data

    NASA Astrophysics Data System (ADS)

    Mareschal, Jean-Claude; Pickler, Carolyne; Beltrami, Hugo

    2016-04-01

    We measured and inverted thirteen temperature-depth profiles (≥1500 m) in boreholes in eastern and central Canada to determine the ground surface temperature histories during and after the last glacial cycle. The sites are located in the southern part of the region covered by the Laurentide Ice Sheet. The inversions yield ground surface temperatures ranging from -1.4 to 3.0oC throughout the last glacial cycle. These temperatures, near the pressure melting point of ice, demonstrate that the southern portion of the Laurentide Ice Sheet was not frozen to the bed, allowing for basal flow and fast flowing ice streams at the base. Despite such conditions, which have been inferred from geomorphological data and models, the ice sheet persisted throughout the last glacial cycle. Our results suggest some regional trends in basal temperatures with possible control by internal heat flow.

  12. Influence of mold surface temperature on polymer part warpage in rapid heat cycle molding

    NASA Astrophysics Data System (ADS)

    Berger, G. R.; Pacher, G. A.; Pichler, A.; Friesenbichler, W.; Gruber, D. P.

    2014-05-01

    Dynamic mold surface temperature control was examined for its influence on the warpage. A test mold, featuring two different rapid heat cycle molding (RHCM) technologies was used to manufacture complex plate-shaped parts having different ribs, varying thin-wall regions, and both, circular and rectangular cut-outs. The mold's nozzle side is equipped with the areal heating and cooling technology BFMOLD®, where the heating/cooling channels are replaced by a ball-filled slot near the cavity surface flooded through with hot and cold water sequentially. Two local electrical ceramic heating elements are installed into the mold's ejection side. Based on a 23 full-factorial design of experiments (DoE) plan, varying nozzle temperature (Tnozzle), rapid heat cycle molding temperature (TRHCM) and holding pressure (pn), specimens of POM were manufactured systematically. Five specimens were examined per DoE run. The resulting warpage was measured at 6 surface line scans per part using the non-contact confocal topography system FRT MicroProf®. Two warpage parameters were calculated, the curvature of a 2nd order approximation a, and the vertical deflection at the profile center d. Both, the influence strength and the acting direction of the process parameters and their interactions on a and d were calculated by statistical analysis. Linear mathematical process models were determined for a and d to predict the warpage as a function of the process parameter settings. Finally, an optimum process setting was predicted, based on the process models and Microsoft Excel GRG solver. Clear and significant influences of TRHCM, pn, Tnozzle, and the interaction of TRHCM and pn were determined. While TRHCM was dominant close to the gate, pn became more effective as the flow length increased.

  13. 40 CFR Appendix II to Part 1054 - Duty Cycles for Laboratory Testing

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... during idle at its warm idle speed as described in 40 CFR 1065.510. (b) Test nonhandheld engines with one... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Duty Cycles for Laboratory Testing II.... 1054, App. II Appendix II to Part 1054—Duty Cycles for Laboratory Testing (a) Test handheld...

  14. Conducting High Cycle Fatigue Strength Step Tests on Gamma TiAl

    NASA Technical Reports Server (NTRS)

    Lerch, Brad; Draper, Sue; Pereira, J. Mike

    2002-01-01

    High cycle fatigue strength testing of gamma TiAl by the step test method is investigated. A design of experiments was implemented to determine if the coaxing effect occurred during testing. Since coaxing was not observed, step testing was deemed a suitable method to define the fatigue strength at 106 cycles.

  15. 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...

  16. 40 CFR Appendix II to Part 1054 - Duty Cycles for Laboratory Testing

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... during idle at its warm idle speed as described in 40 CFR 1065.510. (b) Test nonhandheld engines with one... 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...

  17. Effect of menstrual cycle phase on the ventilatory response to rising body temperature during exercise.

    PubMed

    Hayashi, Keiji; Kawashima, Takayo; Suzuki, Yuichi

    2012-07-01

    To examine the effect of menstrual cycle on the ventilatory sensitivity to rising body temperature, ten healthy women exercised for ~60 min on a cycle ergometer at 50% of peak oxygen uptake during the follicular and luteal phases of their cycle. Esophageal temperature, mean skin temperature, mean body temperature, minute ventilation, and tidal volume were all significantly higher at baseline and during exercise in the luteal phase than the follicular phase. On the other hand, end-tidal partial pressure of carbon dioxide was significantly lower during exercise in the luteal phase than the follicular phase. Plotting ventilatory parameters against esophageal temperature revealed there to be no significant menstrual cycle-related differences in the slopes or intercepts of the regression lines, although minute ventilation and tidal volume did significantly differ during exercise with mild hyperthermia. To evaluate the cutaneous vasodilatory response, relative laser-Doppler flowmetry values were plotted against mean body temperature, which revealed that the mean body temperature threshold for cutaneous vasodilation was significantly higher in the luteal phase than the follicular phase, but there were no significant differences in the sensitivity or peak values. These results suggest that the menstrual cycle phase influences the cutaneous vasodilatory response during exercise and the ventilatory response at rest and during exercise with mild hyperthermia, but it does not influence ventilatory responses during exercise with moderate hyperthermia. PMID:22604882

  18. Parametric Investigation of Brayton Cycle for High Temperature Gas-Cooled Reactor

    SciTech Connect

    Chang Oh

    2004-07-01

    The Idaho National Engineering and Environmental Laboratory (INEEL) is investigating a Brayton cycle efficiency improvement on a high temperature gas-cooled reactor (HTGR) as part of Generation-IV nuclear engineering research initiative. In this project, we are investigating helium Brayton cycles for the secondary side of an indirect energy conversion system. Ultimately we will investigate the improvement of the Brayton cycle using other fluids, such as supercritical carbon dioxide. Prior to the cycle improvement study, we established a number of baseline cases for the helium indirect Brayton cycle. These cases look at both single-shaft and multiple-shaft turbomachinary. The baseline cases are based on a 250 MW thermal pebble bed HTGR. The results from this study are applicable to other reactor concepts such as a very high temperature gas-cooled reactor (VHTR), fast gas-cooled reactor (FGR), supercritical water reactor (SWR), and others. In this study, we are using the HYSYS computer code for optimization of the helium Brayton cycle. Besides the HYSYS process optimization, we performed parametric study to see the effect of important parameters on the cycle efficiency. For these parametric calculations, we use a cycle efficiency model that was developed based on the Visual Basic computer language. As a part of this study we are currently investigated single-shaft vs. multiple shaft arrangement for cycle efficiency and comparison, which will be published in the next paper.The ultimate goal of this study is to use supercritical carbon dioxide for the HTGR power conversion loop in order to improve the cycle efficiency to values great than that of the helium Brayton cycle. This paper includes preliminary calculations of the steady state overall Brayton cycle efficiency based on the pebble bed reactor reference design (helium used as the working fluid) and compares those results with an initial calculation of a CO2 Brayton cycle.

  19. Using Radiocarbon to Test Models of Ecosystem Carbon Cycling

    NASA Astrophysics Data System (ADS)

    Trumbore, S.; Lin, H.; Randerson, J.

    2007-05-01

    The radiocarbon content of carbon stored in and respired by ecosystems provides a direct measure of ecosystem carbon dynamics that can be directly compared to model predictions. Because carbon cycles through ecosystems on a variety of timescales, the mean age of C in standing biomass and soil organic matter pools is older than the mean age of microbially respired carbon. In turn, each pathway for C transit through ecosystems my respond differently to edaphic conditions; for example, soil organic matter mean age is controlled by factors affecting stabilization of C on very long timescales, such as mineralogy, while a factor like litter quality that effects decomposition rates reflects vegetation and climate characteristics. We compare the radiocarbon signature of heterotrophically respired CO2 across a number of ecosystems with models predicted using the CASA ecosystem model. The major controls of microbially respired CO2 from ecosystems include the residence time of C in living plant pools (i.e. the age of C in litter inputs to soil) and factors that control decomposition rates (litter quality and climate). Major differences between model and measured values at low latitudes are related to how woody debris pools are treated differently in models and measurements. The time lag between photosynthesis and respiration is a key ecosystem property that defines its potential to store or release carbon given variations in annual net primary production. Radiocarbon provides a rare case where models can be directly compared with measurements to provide a test of this parameter.

  20. 40 CFR 86.1341-98 - Test cycle validation criteria.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... guidance see § 86.1341-90” (a) Through (b)(2) . For guidance see § 86.1341-90. (b)(3) All feedback torques... reference idle portions of the cycle where CITT is not applied, use measured torque values for cycle validation and the reference torque values for calculating the brake horsepower-hour value used in...

  1. 40 CFR 86.1341-98 - Test cycle validation criteria.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... guidance see § 86.1341-90” (a) Through (b)(2) . For guidance see § 86.1341-90. (b)(3) All feedback torques... reference idle portions of the cycle where CITT is not applied, use measured torque values for cycle validation and the reference torque values for calculating the brake horsepower-hour value used in...

  2. Evaluation of a Brayton cycle recuperator after 21,000 hours of ground testing

    NASA Technical Reports Server (NTRS)

    Moore, T. J.

    1979-01-01

    A metallographic examination was conducted on a Brayton cycle recuperator and associated ducting after 21,000 hours of ground testing in air. At the hot (turbine) end, the recuperator operated at a nominal temperature of 675 C. The type 347 stainless-steel recuperator performed satisfactorily in the ground test even though the primary working fluid leaked to the atmosphere periodically. The leakage path was located at plate-bar braze joints which cracked as a result of thermal stresses. The welded type 347 stainless steel ducting a type 347/Hastelloy X bellows survived the ground test with no apparent loss of ductility or integrity. Some apparent aging embrittlement was observed in the Hastelloy X ducting but the serviceability was not affected.

  3. Ovarian cycle approach by rectal temperature and fecal progesterone in a female killer whale, Orcinus orca.

    PubMed

    Kusuda, Satoshi; Kakizoe, Yuka; Kanda, Koji; Sengoku, Tomoko; Fukumoto, Yohei; Adachi, Itsuki; Watanabe, Yoko; Doi, Osamu

    2011-01-01

    This study aimed to validate the measurements of body temperature and fecal progesterone concentrations as minimally invasive techniques for assessing ovarian cycle in a single sexually mature female killer whale. Rectal temperature data, fecal and blood samples were collected in the dorsal position using routine husbandry training on a voluntary basis. The correlations between rectal temperature and plasma progesterone concentration and between fecal and plasma progesterone concentrations were investigated. Fecal progesterone metabolites were identified by a combination of high-performance liquid chromatography and enzyme immunoassay. Plasma progesterone concentrations (range: 0.2-18.6 ng/ml) and rectal temperature (range: 35.3-35.9°C) changed cyclically, and cycle lengths were an average (±SD) of 44.9±4.0 days (nine cycles) and 44.6±5.9 days (nine cycles), respectively. Rectal temperature positively correlated with the plasma progesterone concentrations (r=0.641, P<0.01). There was a visual trend for fecal progesterone profiles to be similar to circulating plasma progesterone profiles. Fecal immunoreactive progestagen analysis resulted in a marked immunoreactive peak of progesterone. The data from the single killer whale indicate that the measurement of rectal temperature is suitable for minimally invasive assessment of the estrous cycle and monitoring the fecal progesterone concentration is useful to assess ovarian luteal activity. PMID:20648568

  4. Physiological and Transcriptional Responses of Anaerobic Chemostat Cultures of Saccharomyces cerevisiae Subjected to Diurnal Temperature Cycles

    PubMed Central

    Hebly, Marit; de Ridder, Dick; de Hulster, Erik A. F.; de la Torre Cortes, Pilar; Pronk, Jack T.

    2014-01-01

    Diurnal temperature cycling is an intrinsic characteristic of many exposed microbial ecosystems. However, its influence on yeast physiology and the yeast transcriptome has not been studied in detail. In this study, 24-h sinusoidal temperature cycles, oscillating between 12°C and 30°C, were imposed on anaerobic, glucose-limited chemostat cultures of Saccharomyces cerevisiae. After three diurnal temperature cycles (DTC), concentrations of glucose and extracellular metabolites as well as CO2 production rates showed regular, reproducible circadian rhythms. DTC also led to waves of transcriptional activation and repression, which involved one-sixth of the yeast genome. A substantial fraction of these DTC-responsive genes appeared to respond primarily to changes in the glucose concentration. Elimination of known glucose-responsive genes revealed an overrepresentation of previously identified temperature-responsive genes as well as genes involved in the cell cycle and de novo purine biosynthesis. In-depth analysis demonstrated that DTC led to a partial synchronization of the cell cycle of the yeast populations in chemostat cultures, which was lost upon release from DTC. Comparison of DTC results with data from steady-state cultures showed that the 24-h DTC was sufficiently slow to allow S. cerevisiae chemostat cultures to acclimate their transcriptome and physiology at the DTC temperature maximum and to approach acclimation at the DTC temperature minimum. Furthermore, this comparison and literature data on growth rate-dependent cell cycle phase distribution indicated that cell cycle synchronization was most likely an effect of imposed fluctuations of the relative growth rate (μ/μmax) rather than a direct effect of temperature. PMID:24814792

  5. Physiological and transcriptional responses of anaerobic chemostat cultures of Saccharomyces cerevisiae subjected to diurnal temperature cycles.

    PubMed

    Hebly, Marit; de Ridder, Dick; de Hulster, Erik A F; de la Torre Cortes, Pilar; Pronk, Jack T; Daran-Lapujade, Pascale

    2014-07-01

    Diurnal temperature cycling is an intrinsic characteristic of many exposed microbial ecosystems. However, its influence on yeast physiology and the yeast transcriptome has not been studied in detail. In this study, 24-h sinusoidal temperature cycles, oscillating between 12°C and 30°C, were imposed on anaerobic, glucose-limited chemostat cultures of Saccharomyces cerevisiae. After three diurnal temperature cycles (DTC), concentrations of glucose and extracellular metabolites as well as CO2 production rates showed regular, reproducible circadian rhythms. DTC also led to waves of transcriptional activation and repression, which involved one-sixth of the yeast genome. A substantial fraction of these DTC-responsive genes appeared to respond primarily to changes in the glucose concentration. Elimination of known glucose-responsive genes revealed an overrepresentation of previously identified temperature-responsive genes as well as genes involved in the cell cycle and de novo purine biosynthesis. In-depth analysis demonstrated that DTC led to a partial synchronization of the cell cycle of the yeast populations in chemostat cultures, which was lost upon release from DTC. Comparison of DTC results with data from steady-state cultures showed that the 24-h DTC was sufficiently slow to allow S. cerevisiae chemostat cultures to acclimate their transcriptome and physiology at the DTC temperature maximum and to approach acclimation at the DTC temperature minimum. Furthermore, this comparison and literature data on growth rate-dependent cell cycle phase distribution indicated that cell cycle synchronization was most likely an effect of imposed fluctuations of the relative growth rate (μ/μmax) rather than a direct effect of temperature. PMID:24814792

  6. Evidence for Solar-Cycle Forcing and Secular Variation in the Armagh Observatory Temperature Record

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    1998-01-01

    A prominent feature of previous long-term temperature studies has been the appearance of warming since the 1880s, this often being taken as evidence for anthropogenic-induced global warming. In this investigation, the long-term, annual, mean temperature record (1844-1992) of the Armagh Observatory (Armagh, North Ireland), a set of temperature data based on maximum and minimum thermometers that predates the 1880s and correlates well with northern hemispheric and global standards, is examined for evidence of systematic variation, in particular, as related to solar-cycle forcing and secular variation. Indeed, both appear to be embedded within the Armagh data. Removal of these effects, each contributing about 8% to the overall reduction in variance, yields residuals that are randomly distributed. Application of the 10-year moving average to the residuals, furthermore, strongly suggests that the behavior of the residuals is episodic, inferring that (for extended periods of time) temperatures at Armagh sometimes were warmer or cooler (than expected), while at other times they were stable. Comparison of cyclic averages of annual mean temperatures against the lengths of the associated Hale cycles (i.e., the length of two, sequentially numbered, even-odd sunspot cycle pairs) strongly suggests that the temperatures correlate inversely (r = -0.886 at less than 2% level of significance) against the length of the associated Hale cycle. Because sunspot cycle 22 ended in 1996, the present Hale cycle probably will be shorter than average, implying that temperatures at Armagh over this Hale cycle will be warmer (about 9.31 q 0.23 C at the 90% confidence level) than average (= 9.00 C).

  7. FREEZE-THAW CYCLING AND COLD TEMPERATURE EFFECTS ON GEOMEMBRANE SHEETS AND SEAMS. Project summary

    EPA Science Inventory

    The effects of freeze-thaw cycling on the tensile strength of 19 geomembranes and 31 different seam types were investigated. The study was performed in three parts using different test conditions. Part I involved incubating unconfined specimens in freeze-thaw cycles and then per...

  8. 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.

  9. The impact of component performance on the overall cycle performance of small-scale low temperature organic Rankine cycles

    NASA Astrophysics Data System (ADS)

    White, M.; Sayma, A. I.

    2015-08-01

    Low temperature organic Rankine cycles offer a promising technology for the generation of power from low temperature heat sources. Small-scale systems (∼10kW) are of significant interest, however there is a current lack of commercially viable expanders. For a potential expander to be economically viable for small-scale applications it is reasonable to assume that the same expander must have the ability to be implemented within a number of different ORC applications. It is therefore important to design and optimise the cycle considering the component performance, most notably the expander, both at different thermodynamic conditions, and using alternative organic fluids. This paper demonstrates a novel modelling methodology that combines a previously generated turbine performance map with cycle analysis to establish at what heat source conditions optimal system performance can be achieved using an existing turbine design. The results obtained show that the same turbine can be effectively utilised within a number of different ORC applications by changing the working fluid. By selecting suitable working fluids, this turbine can be used to convert pressurised hot water at temperatures between 360K and 400K, and mass flow rates between 0.45kg/s and 2.7kg/s, into useful power with outputs between 1.5kW and 27kW. This is a significant result since it allows the same turbine to be implemented into a variety of applications, improving the economy of scale. This work has also confirmed the suitability of the candidate turbine for a range of low temperature ORC applications.

  10. 33 CFR 159.119 - Operability test; temperature range.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Operability test; temperature range. 159.119 Section 159.119 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... Operability test; temperature range. The device must operate in an ambient temperature of 5 °C with...

  11. Sacramento Power Authority experience of building and testing a successful turn key combined cycle project

    SciTech Connect

    Maring, J.; Yost, J.; Zachary, J.

    1998-07-01

    The following paper will describe a combined cycle power plant providing power and steam to a food processing plant. The project owner is Sacramento Power Authority in Sacramento, California, USA. A consortium led by Siemens supplied the equipment and provided the turn key project management. The project was completed in 23 months and the plant was released for dispatch 3 weeks ahead of schedule. The formal performance tests conducted in December 1997, indicated a better net output and a lower net heat rate from the guaranteed values. The thermal acceptance test procedure was in full compliance with the new Performance Test Code PTC-46 of the American Society of Mechanical Engineers (ASME) for combined cycle power plant testing, issued in 1996 and also met all the requirements of ISO 2314 Procedure. The paper will also discuss the performance of an evaporative cooler, used to lower compressor air inlet temperature and the methodology used to reduce the additional instrumentation uncertainty associated with such devices. The paper will also deal with the unique environmental emissions restrictions imposed on the project.

  12. Specimen for high-temperature tensile tests

    NASA Technical Reports Server (NTRS)

    Coulbert, C. D.

    1972-01-01

    Split nut with internal taper to hold specially formed specimen composed of filaments of refractory material provides means for holding at high temperature and under tension so that performance evaluations may be made.

  13. Irradiation data for the MFA-1 and MFA-2 tests during FFTF cycles 10A and 10B

    SciTech Connect

    Nelson, J.V.

    1996-10-30

    This report provides key information on the irradiation environment of the MONJU fuel test MFA-1 and MFA-2 in the Fast Flux Test Facility (FFTF) during operating cycles 10A and 10B.This information includes the fission powers, neutron fluxes, sodium temperatures and sodium flow rates in MFA-1, MFA-2, and adjacent assemblies. It also includes MFA-1 and MFA-2 compositions as a function of exposure during cycles 10A and 10B. The work was performed at the request of Power Reactor and Nuclear Fuels (PNC) of Japan.

  14. A New High-Speed, High-Cycle, Gear-Tooth Bending Fatigue Test Capability

    NASA Technical Reports Server (NTRS)

    Stringer, David B.; Dykas, Brian D.; LaBerge, Kelsen E.; Zakrajsek, Andrew J.; Handschuh, Robert F.

    2011-01-01

    A new high-speed test capability for determining the high cycle bending-fatigue characteristics of gear teeth has been developed. Experiments were performed in the test facility using a standard spur gear test specimens designed for use in NASA Glenn s drive system test facilities. These tests varied in load condition and cycle-rate. The cycle-rate varied from 50 to 1000 Hz. The loads varied from high-stress, low-cycle loads to near infinite life conditions. Over 100 tests were conducted using AISI 9310 steel spur gear specimen. These results were then compared to previous data in the literature for correlation. Additionally, a cycle-rate sensitivity analysis was conducted by grouping the results according to cycle-rate and comparing the data sets. Methods used to study and verify load-path and facility dynamics are also discussed.

  15. High-temperature testing of glass/ceramic matrix composites

    NASA Technical Reports Server (NTRS)

    Mandell, John F.; Grande, Dodd H.; Dannemann, Kathryn A.

    1989-01-01

    Recent advances in ceramic and other high-temperature composites have created a need for test methods that can be used at 1000 C and above. Present test methods usually require adhesively bonded tabs that cannot be used at high temperatures. This paper discusses some of the difficulties with high-temperature test development and describes several promising test methods. Stress-strain data are given for Nicalon ceramic fiber reinforced glass and glass-ceramic matrix composites tested in air at temperatures up to 1000 C.

  16. Evaluation of Giga-cycle Fatigue Properties of Austenitic Stainless Steels Using Ultrasonic Fatigue Test

    NASA Astrophysics Data System (ADS)

    Takahashi, Kyouhei; Ogawa, Takeshi

    Ultrasonic fatigue tests have been performed in austenitic stainless steel, SUS316NG, in order to investigate giga-cycle fatigue strength of pre-strained materials, i.e. 5, 10 and 20% tensile pre-strains and -20% compressive pre-strain. The pre-strains were applied before specimen machining. The austenitic stainless steels are known to exhibit remarkable self-heating during the fatigue experiment. Therefore, heat radiation method was established by setting fatigue specimens in a low temperature chamber at about -100°C. The self-heating was controlled by intermittent loading condition, which enabled us to maintain the test section of the specimens at about room temperature. The results revealed that the fatigue strength increased with increasing pre-strain levels. Fish-eye fracture was observed for -20% pre-strained specimen fractured at 4.11×107 cycles, while the other specimens exhibited ordinary fatigue fracture surface originated from stage I facet on the specimen surface. The increase in fatigue limit was predicted by Vickers hardness, HV, which depended on the size of indented region. The prediction was successful using HV values obtained by the size of the indented region similar to those of the stage I facets.

  17. A two-fold increase of carbon cycle sensitivity to tropical temperature variations.

    PubMed

    Wang, Xuhui; Piao, Shilong; Ciais, Philippe; Friedlingstein, Pierre; Myneni, Ranga B; Cox, Peter; Heimann, Martin; Miller, John; Peng, Shushi; Wang, Tao; Yang, Hui; Chen, Anping

    2014-02-13

    Earth system models project that the tropical land carbon sink will decrease in size in response to an increase in warming and drought during this century, probably causing a positive climate feedback. But available data are too limited at present to test the predicted changes in the tropical carbon balance in response to climate change. Long-term atmospheric carbon dioxide data provide a global record that integrates the interannual variability of the global carbon balance. Multiple lines of evidence demonstrate that most of this variability originates in the terrestrial biosphere. In particular, the year-to-year variations in the atmospheric carbon dioxide growth rate (CGR) are thought to be the result of fluctuations in the carbon fluxes of tropical land areas. Recently, the response of CGR to tropical climate interannual variability was used to put a constraint on the sensitivity of tropical land carbon to climate change. Here we use the long-term CGR record from Mauna Loa and the South Pole to show that the sensitivity of CGR to tropical temperature interannual variability has increased by a factor of 1.9 ± 0.3 in the past five decades. We find that this sensitivity was greater when tropical land regions experienced drier conditions. This suggests that the sensitivity of CGR to interannual temperature variations is regulated by moisture conditions, even though the direct correlation between CGR and tropical precipitation is weak. We also find that present terrestrial carbon cycle models do not capture the observed enhancement in CGR sensitivity in the past five decades. More realistic model predictions of future carbon cycle and climate feedbacks require a better understanding of the processes driving the response of tropical ecosystems to drought and warming. PMID:24463514

  18. A two-fold increase of carbon cycle sensitivity to tropical temperature variations

    NASA Astrophysics Data System (ADS)

    Wang, Xuhui; Piao, Shilong; Ciais, Philippe; Friedlingstein, Pierre; Myneni, Ranga B.; Cox, Peter; Heimann, Martin; Miller, John; Peng, Shushi; Wang, Tao; Yang, Hui; Chen, Anping

    2014-02-01

    Earth system models project that the tropical land carbon sink will decrease in size in response to an increase in warming and drought during this century, probably causing a positive climate feedback. But available data are too limited at present to test the predicted changes in the tropical carbon balance in response to climate change. Long-term atmospheric carbon dioxide data provide a global record that integrates the interannual variability of the global carbon balance. Multiple lines of evidence demonstrate that most of this variability originates in the terrestrial biosphere. In particular, the year-to-year variations in the atmospheric carbon dioxide growth rate (CGR) are thought to be the result of fluctuations in the carbon fluxes of tropical land areas. Recently, the response of CGR to tropical climate interannual variability was used to put a constraint on the sensitivity of tropical land carbon to climate change. Here we use the long-term CGR record from Mauna Loa and the South Pole to show that the sensitivity of CGR to tropical temperature interannual variability has increased by a factor of 1.9+/-0.3 in the past five decades. We find that this sensitivity was greater when tropical land regions experienced drier conditions. This suggests that the sensitivity of CGR to interannual temperature variations is regulated by moisture conditions, even though the direct correlation between CGR and tropical precipitation is weak. We also find that present terrestrial carbon cycle models do not capture the observed enhancement in CGR sensitivity in the past five decades. More realistic model predictions of future carbon cycle and climate feedbacks require a better understanding of the processes driving the response of tropical ecosystems to drought and warming.

  19. Testing the effects of temperature and humidity on printed passive UHF RFID tags on paper substrate

    NASA Astrophysics Data System (ADS)

    Linnea Merilampi, Sari; Virkki, Johanna; Ukkonen, Leena; Sydänheimo, Lauri

    2014-05-01

    This article is an interesting substrate material for environmental-friendly printable electronics. In this study, screen-printed RFID tags on paper substrate are examined. Their reliability was tested with low temperature, high temperature, slow temperature cycling, high temperature and high humidity and water dipping test. Environmental stresses affect the tag antenna impedance, losses and radiation characteristics due to their impact on the ink film and paper substrate. Low temperature, temperature cycling and high humidity did not have a radical effect on the measured parameters: threshold power, backscattered signal power or read range of the tags. However, the frequency response and the losses of the tags were slightly affected. Exposure to high temperature was found to even improve the tag performance due to the positive effect of high temperature on the ink film. The combined high humidity and high temperature had the most severe effect on the tag performance. The threshold power increased, backscattered power decreased and the read range was shortened. On the whole, the results showed that field use of these tags in high, low and changing temperature conditions and high humidity conditions is possible. Use of these tags in combined high-humidity and high-temperature conditions should be carefully considered.

  20. 40 CFR 1039.510 - Which duty cycles do I use for transient testing?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CFR 1065.514 to confirm that the test is valid. ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Which duty cycles do I use for... ENGINES Test Procedures § 1039.510 Which duty cycles do I use for transient testing? (a) Measure...

  1. 40 CFR 1039.510 - Which duty cycles do I use for transient testing?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Which duty cycles do I use for... ENGINES Test Procedures § 1039.510 Which duty cycles do I use for transient testing? (a) Measure emissions... CFR 1065.514 to confirm that the test is valid....

  2. A modified heat leak test facility employing a closed-cycle helium refrigerator

    NASA Astrophysics Data System (ADS)

    Boroski, William N.

    A Heat Leak Test Facility (HLTF) has been in use at Fermilab for many years. The apparatus has successfully measured the thermal performance of a variety of cryostat components under simulated operating conditions. While an effective tool in the cryostat design process, the HLTF has several limitations. Temperatures are normally fixed at cryogen boiling points and run times are limited to cryogen inventory. Moreover, close personnel attention is required to maintain system inventories and sustain system equilibrium. To provide longer measurement periods without perturbation and to minimize personnel interaction, a new heat leak measurement facility (HLTF-2) has been designed that incorporates a closed-cycle helium refrigerator. The two-stage refrigerator provides cooling to the various temperature stations of the HLTF while eliminating the need for cryogens. Eliminating cryogen inventories has resulted in a reduction of the amount of direct personnel attention required.

  3. A modified heat leak test facility employing a closed-cycle helium refrigerator

    SciTech Connect

    Boroski, W.N.

    1996-01-01

    A Heat Leak Test Facility (HLTF) has been in use at Fermilab for many years. The apparatus has successfully measured the thermal performance of a variety of cryostat components under simulated operating conditions. While an effective tool in the cryostat design process, the HLTF has several limitations. Temperatures are normally fixed at cryogen boiling points and run times are limited to cryogen inventory. Moreover, close personnel attention is required to maintain system inventories and sustain system equilibrium. To provide longer measurement periods without perturbation and to minimize personnel interaction, a new heat leak measurement facility (HLTF-2) has been designed that incorporates a closed-cycle helium refrigerator. The two-stage refrigerator provides cooling to the various temperature stations of the HLTF while eliminating the need for cryogens. Eliminating cryogen inventories has resulted in a reduction of the amount of direct personnel attention required.

  4. Capacitor bonding techniques and reliability. [thermal cycling tests

    NASA Technical Reports Server (NTRS)

    Kinser, D. L.; Graff, S. M.; Allen, R. V.; Caruso, S. V.

    1974-01-01

    The effect of thermal cycling on the mechanical failure of bonded ceramic chip capacitors mounted on alumina substrates is studied. It is shown that differential thermal expansion is responsible for the cumulative effects which lead to delayed failure of the capacitors. Harder or higher melting solders are found to be less susceptible to thermal cycling effects, although they are more likely to fail during initial processing operations.

  5. Infrared Temperature Measurements of a Reciprocating Seal Test

    NASA Technical Reports Server (NTRS)

    Meinders, M. A.; Wilcock, D. F.; Winer, W. O.

    1983-01-01

    A system has been developed to perform a computer analysis on surface temperature data in tribological systems, taken by an infrared radiation scanning device. The infrared scanner which normally scans at 25 fields per second and 100 lines per field has been modified to scan any single line at 2500 lines per second. The system was used to analyze four friction experiments as part of a thermal behavior study of Stirling engine seals in cooperation between Georgia Institute of Technology and Mechanical Technology, Incorporated. The friction experiments involved two tribo pairs, Rulon on steel and Rulon on sapphire. The results clearly demonstrate the importance of the relative rate of cooling and the mechanical cycle time of the system. For rapid mechanical cycle times in the friction experiment the surface temperature distribution reflects the distribution of energy input on the surface and the temperatures persist for periods longer than that of the mechanical cycle.

  6. The onion fly modulates the adult eclosion time in response to amplitude of temperature cycle

    NASA Astrophysics Data System (ADS)

    Tanaka, Kazuhiro; Watari, Yasuhiko

    2011-08-01

    To confirm whether the amplitude of diel temperature cycles causes a phase shift of adult eclosion rhythm of the onion fly, Delia antiqua, the peak time ( Ø E) of adult eclosion was determined under various thermoperiods with a fixed temperature either in the warm or cool phase and temperature differences ranging from 1°C to 4°C between the two phases. Irrespective of the temperature level during the warm or cool phase, Ø E occurred earlier with decreasing amplitude of the temperature cycle. The results strongly support the previous conclusion of Tanaka and Watari (Naturwissenschaften 90:76-79, 2003) that D. antiqua responds to the amplitude of temperature cycle as a cue for the circadian adult eclosion timing. The phase advance was larger in thermoperiods with a fixed warm-phase temperature than in those with a fixed cool-phase temperature. This might be ascribed to the interaction between the amplitude and level of temperature in the thermoperiodic regimes.

  7. Characterization of Ternary NiTiPd High-Temperature Shape-Memory Alloys under Load-Biased Thermal Cycling

    NASA Technical Reports Server (NTRS)

    Bigelow, Glen S.; Padula, Santo A.; Noebe, Ronald D.; Garg, Anita; Gaydosh, Darrell

    2010-01-01

    While NiTiPd alloys have been extensively studied for proposed use in high-temperature shape-memory applications, little is known about the shape-memory response of these materials under stress. Consequently, the isobaric thermal cyclic responses of five (Ni,Pd)49.5Ti50.5 alloys with constant stoichiometry and Pd contents ranging from 15 to 46 at. pct were investigated. From these tests, transformation temperatures, transformation strain (which is proportional to work output), and unrecovered strain per cycle (a measure of dimensional instability) were determined as a function of stress for each alloy. It was found that increasing the Pd content over this range resulted in a linear increase in transformation temperature, as expected. At a given stress level, work output decreased while the amount of unrecovered strain produced during each load-biased thermal cycle increased with increasing Pd content, during the initial thermal cycles. However, continued thermal cycling at constant stress resulted in a saturation of the work output and nearly eliminated further unrecovered strain under certain conditions, resulting in stable behavior amenable to many actuator applications.

  8. Body temperature and physical activity correlates of the menstrual cycle in Chacma Baboons (Papio hamadryas ursinus).

    PubMed

    Nyakudya, Trevor T; Fuller, Andrea; Meyer, Leith C R; Maloney, Shane K; Mitchell, Duncan

    2012-12-01

    We investigated the temporal relationship between abdominal temperature, physical activity, perineal swelling, and urinary progesterone and estradiol concentrations over the menstrual cycle in unrestrained captive baboons. Using a miniature temperature-sensitive data logger surgically implanted in the abdominal cavity and an activity data logger implanted subcutaneously on the trunk, we measured, continuously over 6 months at 10-min intervals, abdominal temperature and physical activity patterns in four female adult baboons Papio hamadryas ursinus (12.9-19.9 kg), in cages in an indoor animal facility (22-25°C). We monitored menstrual bleeding and perineal swelling changes, and measured urinary progesterone and estradiol concentrations, daily for up to 6 months, to ascertain the stage and length of the menstrual cycle. The menstrual cycle was 36 ± 2 days (mean ± SD) long and the baboons exhibited cyclic changes in perineal swellings, abdominal temperature, physical activity, urinary progesterone, and estradiol concentrations over the cycle. Mean 24-hr abdominal temperature during the luteal phase was significantly higher than during the periovulatory phase (ANOVA, F((2, 9)) = 4.7; P = 0.04), but not different to that during the proliferative phase. Physical activity followed a similar pattern, with mean 24-hr physical activity almost twice as high in the luteal than in the periovulatory phase (ANOVA, P = 0.58; F((2, 12)) = 5.8). We have characterized correlates of the menstrual cycle in baboons and shown, for the first time, a rhythm of physical activity and abdominal temperature over the menstrual cycle, with a nadir of temperature and activity at ovulation. PMID:22930453

  9. High temperature abatement of acid gases from waste incineration. Part II: Comparative life cycle assessment study.

    PubMed

    Biganzoli, Laura; Racanella, Gaia; Marras, Roberto; Rigamonti, Lucia

    2015-01-01

    The performances of a new dolomitic sorbent, named Depurcal®MG, to be directly injected at high temperature in the combustion chamber of Waste-To-Energy (WTE) plants as a preliminary stage of deacidification, were experimentally tested during full-scale commercial operation. Results of the experimentations were promising, and have been extensively described in Biganzoli et al. (2014). This paper reports the Life Cycle Assessment (LCA) study performed to compare the traditional operation of the plants, based on the sole sodium bicarbonate feeding at low temperature, with the new one, where the dolomitic sorbent is injected at high temperature. In the latter the sodium bicarbonate is still used, but at lower rate because of the decreased load of acid gases entering the flue gas treatment line. The major goal of the LCA was to make sure that a burden shifting was not taking place somewhere in the life cycle stages, as it might be the case when a new material is used in substitution of another one. According to the comparative approach, only the processes which differ between the two operational modes were included in the system boundaries. They are the production of the two reactants and the treatment of the corresponding solid residues arising from the neutralisation of acid gases. The additional CO2 emission at the stack of the WTE plant due to the activation of the sodium bicarbonate was also included in the calculation. Data used in the modelling of the foreground system are primary, derived from the experimental tests described in Biganzoli et al. (2014) and from the dolomitic sorbent production plant. The results of the LCA show minor changes in the potential impacts between the two operational modes of the plants. These differences are for 8 impact categories in favour of the new operational mode based on the addition of the dolomitic sorbent, and for 7 impact categories in favour of the traditional operation. A final evaluation was conducted on the potential

  10. Field testing of a high-temperature aquifer thermal energy storage system

    SciTech Connect

    Sterling, R.L.; Hoyer, M.C.

    1989-03-01

    The University of Minnesota Aquifer Thermal Energy Storage (ATES) System has been operated as a field test facility for the past six years. Four short-term and two long-term cycles have been completed to data providing a greatly increased understanding of the efficiency and geochemical effects of high-temperature aquifer thermal energy storage. A third long-term cycle is currently being planned to operate the ATES system in conjunction with a real heating load and to further study the geochemical impact on the aquifer from heated waste storage cycles. The most critical activities in the preparation for the next cycle have proved to be the applications for the various permits and variances necessary to conduct the third cycle and the matching of the characteristics of the ATES system during heat recovery with a suitable adjacent building thermal load.

  11. HEAVY-DUTY TRUCK TEST CYCLES: COMBINING DRIVEABILITY WITH REALISTIC ENGINE EXERCISE

    EPA Science Inventory

    Heavy-duty engine certification testing uses a cycle that is scaled to the capabilities of each engine. As such, every engine should be equally challenged by the cycle's power demands. It would seem that a chassis cycle, similarly scaled to the capabilities of each vehicle, could...

  12. Low-Temperature Multiple-Reheat Closed Gas Power Cycles for the AHTR and LSFR

    SciTech Connect

    Haihua, Zhao; Peterson, Per F.

    2006-07-01

    High Temperature Gas Cooled Reactors (HTGR) such as GT-MHR and PBMR with direct closed gas-turbine Brayton cycle can achieve efficiency between 44% to 48% with core outlet temperatures from 850 deg. C to 900 deg. C. The use of multiple reheat and inter-cooling stages can further improve thermal efficiency. Low-temperature multiple reheat cycles for the AHTR-MI and liquid-salt fast reactors (LSFR), with core outlet temperatures ranging from 620 deg. C to 750 deg. C, can reach similar efficiency as these direct-cycle HTGRs but with reduced technical risk due to lower temperatures. This paper discusses design optimization at these lower temperatures for multiple reheat closed gas cycles and vertical and horizontal arrangement options for power conversion units (PCU). Figures of merit such as specific power density, specific steel input, and specific helium inventory are estimated for different PCU arrangement configurations. With similar components parameters and reasonable arrangement, different configurations such as horizontal or vertical shaft, integrated system or distributed system, were compared. Among those configurations, integrated systems basing on the GT-MHR PCU design result in the highest specific power density and lowest specific steel input. Because the differences in these high-level performance parameters are not large enough to de-select any configurations, further detailed design and comparison must be performed to select optimal system designs. (authors)

  13. Improving the long-term cycling performance of lithium-ion batteries at elevated temperature with electrolyte additives

    NASA Astrophysics Data System (ADS)

    Xia, Jian; Ma, Lin; Dahn, J. R.

    2015-08-01

    The effects of vinylene carbonate-based and prop-1-ene-1,3-sultone-based electrolyte additives on the cycling behavior of Li[Ni1/3Mn1/3Co1/3]O2/graphite pouch type cells at elevated temperature have been systematically studied. Capacity fade during cycling, charge-transfer resistance before and after cycling as well as gas evolution during formation and also during cycling were examined and compared. For vinylene carbonate-based additive blends, only 3% vinylene carbonate, 2% vinylene carbonate + 1% 1,3,2-dioxathiolane-2,2-dioxide + 1% tris(trimethylsilyl) phosphite or 2% vinylene carbonate + 1% methylene methyl disulfonate + 1% tris(trimethylsilyl) phosphite showed less capacity fade than 2% vinylene carbonate alone. Cells with all of these vinylene carbonate-based electrolyte additive blends lost more than 20% of their initial capacity after ∼1000 cycles at 55 °C and all the vinylene carbonate-based cells swelled more than 10% of their initial volume during this test. Cells containing all prop-1-ene-1,3-sultone-based additive blends generally produced much less gas than the vinylene carbonate-based blends. Many cells containing prop-1-ene-1,3-sultone-based additive blends lost less than 20% of their initial capacity after 1000 cycles. Moreover, the impedance of these prop-1-ene-1,3-sultone-based electrolytes decreased after long-term cycling. These results suggest that prop-1-ene-1,3-sultone-based electrolytes are more useful than vinylene carbonate-based electrolytes at high temperatures in Li[Ni1/3Mn1/3Co1/3]O2/graphite cells.

  14. Effect on combined cycle efficiency of stack gas temperature constraints to avoid acid corrosion

    NASA Technical Reports Server (NTRS)

    Nainiger, J. J.

    1980-01-01

    To avoid condensation of sulfuric acid in the gas turbine exhaust when burning fuel oils contaning sulfur, the exhaust stack temperature and cold-end heat exchanger surfaces must be kept above the condensation temperature. Raising the exhaust stack temperature, however, results in lower combined cycle efficiency compared to that achievable by a combined cycle burning a sulfur-free fuel. The maximum difference in efficiency between the use of sulfur-free and fuels containing 0.8 percent sulfur is found to be less than one percentage point. The effect of using a ceramic thermal barrier coating (TBC) and a fuel containing sulfur is also evaluated. The combined-cycle efficiency gain using a TBC with a fuel containing sulfur compared to a sulfur-free fuel without TBC is 0.6 to 1.0 percentage points with air-cooled gas turbines and 1.6 to 1.8 percentage points with water-cooled gas turbines.

  15. HMM-based estimation of menstrual cycle from skin temperature during sleep.

    PubMed

    Chen, Wenxi; Kitazawa, Masumi; Togawa, Tatsuo

    2008-01-01

    An HMM-based method is proposed to estimate biphasic property in female menstrual cycle. A tiny device is developed to measure skin temperature change during sleep. Data are collected from 30 female participants for 6 months. Raw data are preprocessed to remove obvious outliers and clamped between 34 and 42 degree Celsius. A two hidden states HMM-based algorithm was applied to estimate the biphasic property in menstrual cycle. The results showed that the number of correctly detected menstrual cycle is 159 among 173 in 30 participants during 6 months. Overall sensitivity reaches 92.0%. PMID:19162990

  16. A Statistical Test of Uniformity in Solar Cycle Indices

    NASA Technical Reports Server (NTRS)

    Hathaway David H.

    2012-01-01

    Several indices are used to characterize the solar activity cycle. Key among these are: the International Sunspot Number, the Group Sunspot Number, Sunspot Area, and 10.7 cm Radio Flux. A valuable aspect of these indices is the length of the record -- many decades and many (different) 11-year cycles. However, this valuable length-of-record attribute has an inherent problem in that it requires many different observers and observing systems. This can lead to non-uniformity in the datasets and subsequent erroneous conclusions about solar cycle behavior. The sunspot numbers are obtained by counting sunspot groups and individual sunspots on a daily basis. This suggests that the day-to-day and month-to-month variations in these numbers should follow Poisson Statistics and be proportional to the square-root of the sunspot numbers themselves. Examining the historical records of these indices indicates that this is indeed the case - even with Sunspot Area and 10.7 cm Radio Flux. The ratios of the RMS variations to the square-root of the indices themselves are relatively constant with little variation over the phase of each solar cycle or from small to large solar cycles. There are, however, important step-like changes in these ratios associated with changes in observer and/or observer system. Here we show how these variations can be used to construct more uniform datasets.

  17. Evaluation of Indirect Combined Cycle in Very High Temperature Gas--Cooled Reactor

    SciTech Connect

    Chang Oh; Robert Barner; Cliff Davis; Steven Sherman; Paul Pickard

    2006-10-01

    The U.S. Department of Energy and Idaho National Laboratory are developing a very high temperature reactor to serve as a demonstration of state-of-the-art nuclear technology. The purpose of the demonstration is twofold: (a) efficient, low-cost energy generation and (b) hydrogen production. Although a next-generation plant could be developed as a single-purpose facility, early designs are expected to be dual purpose, as assumed here. A dual-purpose design with a combined cycle of a Brayton top cycle and a bottom Rankine cycle was investigated. An intermediate heat transport loop for transporting heat to a hydrogen production plant was used. Helium, CO2, and a helium-nitrogen mixture were studied to determine the best working fluid in terms of the cycle efficiency. The relative component sizes were estimated for the different working fluids to provide an indication of the relative capital costs. The relative size of the turbomachinery was measured by comparing the power input/output of the component. For heat exchangers the volume was computed and compared. Parametric studies away from the baseline values of the cycle were performed to determine the effects of varying conditions in the cycle. This gives some insight into the sensitivity of the cycle to various operating conditions as well as trade-offs between efficiency and component size. Parametric studies were carried out on reactor outlet temperature, mass flow, pressure, and turbine cooling.

  18. High-temperature, low-cycle fatigue of advanced copper-base alloys for rocket nozzles. Part 1: Narloy Z

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

    Short-term tensile and low-cycle fatigue data are reported for Narloy Z, a centrifugally cast, copper-base alloy. Tensile tests were performed at room temperature in air and in argon at 482, 538 and 593 C using an axial strain rate of .002/sec to the -1 power. In addition tensile tests were performed at 538 C in an evaluation of tensile properties at strain rates of .004 and .01/sec to the -1 power. Ultimate and yield strength values of about 315 and 200 MN/sq m respectively were recorded at room temperature and these decreased to about 120 and 105 respectively as the temperature was increased to 593 C. Reduction in area values were recorded in the range from 40 to 50% with some indication of a minimum ductility point at 538 C.

  19. Life Cycle Testing of Viscoelastic Material for Hubble Space Telescope Solar Array 3 Damper

    NASA Technical Reports Server (NTRS)

    Maly, Joseph R.; Reed, Benjamin B.; Viens, Michael J.; Parker, Bradford H.; Pendleton, Scott C.

    2003-01-01

    During the March 2002 Servicing Mission by Space Shuttle (STS 109), the Hubble Space Telescope (HST) was refurbished with two new solar arrays that now provide all of its power. These arrays were built with viscoelastic/titanium dampers, integral to the supporting masts, which reduce the interaction of the wing bending modes with the Telescope. Damping of over 3% of critical was achieved. To assess the damper s ability to maintain nominal performance over the 10-year on-orbit design goal, material specimens were subjected to an accelerated life test. The test matrix consisted of scheduled events to expose the specimens to pre-determined combinations of temperatures, frequencies, displacement levels, and numbers of cycles. These exposure events were designed to replicate the life environment of the damper from fabrication through testing to launch and life on-orbit. To determine whether material degradation occurred during the exposure sequence, material performance was evaluated before and after the accelerated aging with complex stiffness measurements. Based on comparison of pre- and post-life-cycle measurements, the material is expected to maintain nominal performance through end of life on-orbit. Recent telemetry from the Telescope indicates that the dampers are performing nominally.

  20. 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.

    1990-01-01

    The refrigeration of superconductors in space poses a challenging problem. The problem could be less severe if superconducting materials would not have to be cooled when not in use. Thin films of the YBa2Cu3O(7-x) (YBCO) superconductor were subjected to thermal cycling, which was carried out to simulate a large number of eclipses of a low earth orbit satellite. Electrical measurements were performed to find the effect of the temperature cycling. Thin films of YBCO were formed by coevaporation of Y, BaF2, and Cu and postannealing in wet oxygen at 850 C for 3.5 h. The substrates used were (100) SrTiO3, polycrystalline alumina, and oxidized silicon; the last two have an evaporated zirconia layer. Processing and microstructure studies of these types of films have been published. THe zero resistance transition temperatures of the samples used in this study were 91, 82, and 86 K, respectively. The samples were characterized by four point probe electrical measurements as a function of temperature. The parameters measured were: the zero resistance transition temperature, the 10 to 90 percent transition width, and the room temperature resistance, normalized to that measured before temperature cycling. The results for two samples are presented. Each sample had a cumulative exposure. Cycling in atmospheric pressure nitrogen was performed at a rate of about 60 cycles per day, whereas in vacuum the rate was only about 10 cycles per day. The results indicate only little or no changes in the parameters measured. Degradation of superconducting thin films of YBCO has been reported due to storage in nitrogen. It is believed that the relatively good performance of films after temperature cycling is related to the fact that BaF2 was used as an evaporation source. The latest result on extended temperature cycling indicates significant degradation. Further tests of extended cycling will be carried out to provide additional data and to clarify this preliminary finding.

  1. Elevated temperature fatigue testing of metals

    NASA Technical Reports Server (NTRS)

    Hirschberg, M. H.

    1981-01-01

    The major technology areas needed to perform a life prediction of an aircraft turbine engine hot section component are discussed and the steps required for life prediction are outlined. These include the determination of the operating environment, the calculation of the thermal and mechanical loading of the component, the cyclic stress-strain and creep behavior of the material required for structural analysis, and the structural analysis to determine the local stress-strain-temperature-time response of the material at the critical location in the components. From a knowledge of the fatigue, creep, and failure resistance of the material, a prediction of the life of the component is made. Material characterization and evaluation conducted for the purpose of calculating fatigue crack initiation lives of components operating at elevated temperatures are emphasized.

  2. Influence of temperature, current and number of cycles on the efficiency of the closed oxygen cycle in VRLA batteries

    NASA Astrophysics Data System (ADS)

    Pavlov, D.; Ruevski, S.; Naidenov, V.; Sheytanov, G.

    An experimental method was created for assessment of the efficiency of the closed oxygen cycle in VRLA cells. It was experimentally established that at 25% compression of the AGM separator the battery life is the longest one. On the other hand, the efficiency of the closed oxygen cycle (COC) is the highest at 20% compression of the AGM. With an increase of the compression the efficiency of the COC decreases because of the decreasing of the number of the channels (pores) along which the oxygen flows can move through the AGM separator. It was established that the polarization of the VRLA cell is mainly determined by the resistance arising at transportation of the oxygen through the AGM. There is an upper limit of the rate of recombination of oxygen that depends on the structure and properties of the AGM. With increase of the temperature the efficiency of the COC and polarization of the VRLA cell decrease. During cycling, the properties and structure of the AGM change that affects the parameters of VRLAB.

  3. Laser-driven microsecond temperature cycles analyzed by fluorescence polarization microscopy.

    PubMed

    Zondervan, Rob; Kulzer, Florian; van der Meer, Harmen; Disselhorst, Jos A J M; Orrit, Michel

    2006-04-15

    We demonstrate a novel technique to achieve fast thermal cycles of a small sample (a few femtoliters). Modulating a continuous near-infrared laser focused on a metal film, we can drive the local temperature from 130 to 300 K and back, within a few microseconds. By fluorescence microscopy of dyes in a thin glycerol film, we record images of the hot spot, calibrate its temperature, and follow its variations in real time. The temperature dependence of fluorescence anisotropy, due to photophysics and rotational diffusion, gives a steady-state temperature calibration between 200 and 350 K. From 200 to 220 K, we monitor temperature more accurately by fluorescence autocorrelation, a probe for rotational diffusion. Time-resolved measurements of fluorescence anisotropy give heating and cooling times of a few microseconds, short enough to supercool pure water. We designed our method to repeatedly cycle a single (bio)molecule between ambient and cryostat temperatures with microsecond time resolution. Successive measurements of a structurally relevant variable will decompose a dynamical process into structural snapshots. Such temperature-cycle experiments, which combine a high time resolution with long observation times, can thus be expected to yield new insights into complex processes such as protein folding. PMID:16443653

  4. 40 CFR 86.1341-90 - Test cycle validation criteria.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... between the feedback and reference cycle values, the entire engine speed and torque feedback signal sequence may be advanced or delayed in time with respect to the reference speed and torque sequence. If the feedback signals are shifted, both speed and torque must be shifted the same amount in the same...

  5. 40 CFR 89.410 - Engine test cycle.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... to the discrete-mode duty cycles specified in this section, as described in 40 CFR 1039.505. ... the throttle must be in the fully closed position and torque must not exceed 5 percent of the peak torque value of mode 5. (c) For any mode except those involving either idle or full-load operation,...

  6. 40 CFR 86.1341-90 - Test cycle validation criteria.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... between the feedback and reference cycle values, the entire engine speed and torque feedback signal sequence may be advanced or delayed in time with respect to the reference speed and torque sequence. If the feedback signals are shifted, both speed and torque must be shifted the same amount in the same...

  7. Apparatus for elevated temperature compression or tension testing of specimens

    NASA Astrophysics Data System (ADS)

    Gates, Thomas S.

    1992-05-01

    In order to support materials selection for the next generation supersonic civilian passenger transport aircraft, a testing apparatus was developed to evaluate certain materials under conditions of high load and elevated temperature. In order to elevate the temperature of the material during standard tension and compression testing the test specimen is surrounded by a pair of supports which include internal heating means. These supports also prevent buckling of the specimen during compression testing.

  8. Increased winter soil temperature variability enhances nitrogen cycling and soil biotic activity in temperate heathland and grassland mesocosms

    NASA Astrophysics Data System (ADS)

    Schuerings, J.; Jentsch, A.; Hammerl, V.; Lenz, K.; Henry, H. A. L.; Malyshev, A. V.; Kreyling, J.

    2014-12-01

    Winter air temperatures are projected to increase in the temperate zone, whereas snow cover is projected to decrease, leading to increased soil temperature variability, and potentially to changes in nutrient cycling. Here, we experimentally evaluated the effects of increased winter soil temperature variability on selected aspects of the N-cycle in mesocosms containing different plant community compositions. The experiment was replicated at two sites, a colder mountainous upland site with high snow accumulation and a warmer and drier lowland site. Increased soil temperature variability enhanced soil biotic activity for both sites during winter, as indicated by 35% higher nitrogen (N) availability in the soil solution, 40% higher belowground decomposition and a 25% increase in the potential activity of the enzyme cellobiohydrolase. The mobilization of N differed between sites, and the 15N signal in leaves was reduced by 31% in response to winter warming pulses, but only at the cold site, with significant reductions occurring for three of four tested plant species at this site. Furthermore, there was a trend of increased N leaching in response to the recurrent winter warming pulses. Overall, projected winter climate change in the temperate zone, with less snow and more variable soil temperatures, appears important for shifts in ecosystem functioning (i.e. nutrient cycling). While the effects of warming pulses on plant N mobilization did not differ among sites, reduced plant 15N incorporation at the colder temperate site suggests that frost damage may reduce plant N uptake in a warmer world, with important implications for nitrogen cycling and nitrogen losses from ecosystems.

  9. High temperature aqueous stress corrosion testing device

    DOEpatents

    Bornstein, A.N.; Indig, M.E.

    1975-12-01

    A description is given of a device for stressing tensile samples contained within a high temperature, high pressure aqueous environment, thereby permitting determination of stress corrosion susceptibility of materials in a simple way. The stressing device couples an external piston to an internal tensile sample via a pull rod, with stresses being applied to the sample by pressurizing the piston. The device contains a fitting/seal arrangement including Teflon and weld seals which allow sealing of the internal system pressure and the external piston pressure. The fitting/seal arrangement allows free movement of the pull rod and the piston.

  10. Low cycle thermal fatigue testing of beryllium grades for ITER plasma facing components

    SciTech Connect

    Watson, R.D.; Youchison, D.L.; Dombrowski, D.E.; Guiniatouline, R.N.; Kupriynov, I.B.

    1996-02-01

    A novel technique has been used to test the relative low cycle thermal fatigue resistance of different grades of US and Russian beryllium, which is proposed as plasma facing armor for fusion reactor first wall, limiter, and divertor components. The 30 kW electron beam test system at Sandia National Laboratories was used to sweep the beam spot along one direction at 1 Hz. This produces a localized temperature ``spike`` of 750{degree}C for each pass of the beam. Large thermal stresses in excess of the yield strength are generated due to very high spot heat flux, 250 MW/m{sup 2}. Cyclic plastic strains on the order of 0.6% produced visible cracking on the heated surface in less than 3000 cycles. An in-vacuo fiber optic borescope was used to visually inspect the beryllium surfaces for crack initiation. Grades of US beryllium tested included: S-65C, S- 65H, S-200F, S-200F-H, SR-200, I-400, extruded high purity, HIP`d spherical powder, porous beryllium (94% and 98% dense), Be/30% BeO, Be/60% BeO, and TiBe{sub 12}. Russian grades included: TGP-56, TShGT, DShG-200, and TShG-56. Both the number of cycles to crack initiation, and the depth of crack propagation, were measured. The most fatigue resistant grades were S-65C, DShG-200, TShGT, and TShG-56. Rolled sheet Be (SR-200) showed excellent crack propagation resistance in the plane of rolling, despite early formation of delamination cracks. Only one sample showed no evidence of surface melting, Extruded (T). Metallographic and chemical analyses are provided. Good agreement was found between the measured depth of cracks and a 2-D elastic-plastic finite element stress analysis.

  11. A Physics-Based Temperature Stabilization Criterion for Thermal Testing

    NASA Technical Reports Server (NTRS)

    Rickman, Steven L.; Ungar, Eugene K.

    2009-01-01

    Spacecraft testing specifications differ greatly in the criteria they specify for stability in thermal balance tests. Some specify a required temperature stabilization rate (the change in temperature per unit time, dT/dt), some specify that the final steady-state temperature be approached to within a specified difference, delta T , and some specify a combination of the two. The particular values for temperature stabilization rate and final temperature difference also vary greatly between specification documents. A one-size-fits-all temperature stabilization rate requirement does not yield consistent results for all test configurations because of differences in thermal mass and heat transfer to the environment. Applying a steady-state temperature difference requirement is problematic because the final test temperature is not accurately known a priori, especially for powered configurations. In the present work, a simplified, lumped-mass analysis has been used to explore the applicability of these criteria. A new, user-friendly, physics-based approach is developed that allows the thermal engineer to determine when an acceptable level of temperature stabilization has been achieved. The stabilization criterion can be predicted pre-test but must be refined during test to allow verification that the defined level of temperature stabilization has been achieved.

  12. Distribution of radiocarbon as a test of global carbon cycle models

    SciTech Connect

    Jain, A.K.; Wuebbles, D.J.; Kheshgi, H.S.

    1995-03-01

    Accurate global carbon cycle models are needed to estimate the future change of atmospheric CO{sub 2} for specified scenarios of CO{sub 2} emissions. Model accuracy cannot be tested directly because of the difficulty in estimating the carbon flux to the oceans and the terrestrial biosphere. However, one test of model consistency is the requirement that the model reproduce past changes and spatial distributions of {sup 14}C. A model for carbon exchange within and among the atmosphere, oceans, and terrestrial biosphere is found to satisfy this test. The ocean is modeled as an upwelling-diffusion column capped by a mixed layer with recirculation of the polar bottom water to complete the thermohaline circulation. This ocean advection scheme contains only two key dynamic parameters, the vertical eddy diffusivity {kappa} and the upwelling velocity w, which are calibrated to match the vertical distribution of preanthropogenic {sup 14}C. The thermocline depth scale {kappa}/w = 1343 m found by calibration is considerably deeper than that required to match the steady vertical temperature profile (500 m). This is consistent with the hypothesis that isopyncal mixing, which is much more rapid than diapyncal mixing, has a stronger effect on {sup 14}C than on temperature since isopyncals are nearly isothermal. This model is found to match measured values, within measurement error, of the prebomb decrease in {sup 14}C in the atmosphere and the mixed layer due to the Suess effect, the bomb {sup 14}C in the mixed layer, the bomb {sup 14}C penetration depth, the bomb {sup 14}C ocean inventory, and the vertical distribution of total carbon. Results are compared to those of other schematic carbon cycle models as well as those of ocean general circulation models. 95 refs., 9 figs., 3 tabs.

  13. High Temperature Ultrasonic Transducers : Material Selection and Testing

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Bruno, Alessandro

    2012-01-01

    The task of my two-months internship was to test different materials to be used to build an high temperature transducer, to develop some prototypes and to test their performance, to assess the reliability of commercial product rated for such a temperature, as well as to collaborate in developing the signal processing code to measure the condensed water levels.

  14. Graphite/Polyimide Tabs For High-Temperature Tensile Tests

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, John Z.; Papadopoulos, Demetrios S.

    1993-01-01

    Delamination from ceramic composite specimens prevented. Tabs made from composite of graphite and PMR-15 polyimide enable high-temperature tensile testing of flat coupons of ceramic-matrix composites. Also used in high-temperature tensile testing of flat coupons of ceramics, metals, and metal-matrix composites.

  15. 42 CFR 84.98 - Tests during low temperature operation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Tests during low temperature operation. 84.98... SAFETY AND HEALTH RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Self-Contained Breathing Apparatus § 84.98 Tests during low temperature operation. (a) The applicant...

  16. Initial Test Results of a Dual Closed-Brayton-Cycle Power Conversion System

    NASA Technical Reports Server (NTRS)

    Johnson, Paul K.; Mason, Lee S.

    2007-01-01

    The dual Brayton power conversion system constructed for NASA Glenn Research Center (GRC) was acceptance tested April 2007 at Barber-Nichols, Inc., Arvada, Colorado. This uniquely configured conversion system is built around two modified commercial Capstone C30 microturbines and employs two closed-Brayton-cycle (CBC) converters sharing a common gas inventory and common heat source. Because both CBCs share the gas inventory, behavior of one CBC has an impact on the performance of the other CBC, especially when one CBC is standby or running at a different shaft speed. Testing performed to date includes the CBCs operating at equal and unequal shaft speeds. A test was also conducted where one CBC was capped off and the other was operated as a single CBC converter. The dual Brayton configuration generated 10.6 kWe at 75 krpm and a turbine inlet temperature of 817 K. Single Brayton operation generated 14.8 kWe at 90 krpm and a turbine inlet temperature of 925 K.

  17. Temperature control in wafer-level testing of large multi-segment electromigration test structures

    NASA Technical Reports Server (NTRS)

    Zamani, Nasser; Lin, Yu-Sang

    1988-01-01

    The paper describes two methods for maintaining a constant metallization temperature throughout a wafer-level isothermal electromigration test of large multisegment test structures where Joule-heating is high and chip to chuck thermal contact is poor. In the first method, an initial calibration of Joule heating versus metal temperature is carried out. During the isothermal electromigration test, the Joule heating is continuously monitored and the chuck temperature is adjusted based on the calibration results to maintain a constant metal temperature. In the second method, temperature sensors are fabricated on the chip and then the sensors are used to monitor the chip temperature directly. The chuck temperature is then adjusted as needed.

  18. TEMPERATURE REQUIREMENTS OF SOME PERCIDS AND ADAPTATIONS TO THE SEASONAL TEMPERATURE CYCLE

    EPA Science Inventory

    Temperature requirements are reviewed for three North American percids (walleye, Stizostedion vitreum; sauger, S. canadense; and yellow perch, Perca flavescens), three Eurasian percids (perch, P. fluviatilis; pikeperch, S. lucioperca; and ruffe, Gymnocephalus cernua), and nine co...

  19. Thermodynamic modeling and performance analysis of the variable-temperature heat reservoir absorption heat pump cycle

    NASA Astrophysics Data System (ADS)

    Qin, Xiaoyong; Chen, Lingen; Ge, Yanlin; Sun, Fengrui

    2015-10-01

    For practical absorption heat pump (AHP) plants, not all external heat reservoir heat capacities are infinite. External heat reservoir heat capacity should be an effect factor in modeling and performance analysis of AHP cycles. A variable-temperature heat reservoir AHP cycle is modeled, in which internal working substance is working in four temperature levels and all irreversibility factors are considered. The irreversibility includes heat transfer irreversibility, internal dissipation irreversibility and heat leakage irreversibility. The general equations among coefficient of performance (COP), heating load and some key characteristic parameters are obtained. The general and optimal characteristics are obtained by using numerical calculations. Besides, the influences of heat capacities of heat reservoirs, internal dissipation irreversibility, and heat leakage irreversibility on cycle performance are analyzed. The conclusions can offer some guidelines for design and operation of AHP plants.

  20. Preliminary low temperature tests of a digital signal processor

    NASA Technical Reports Server (NTRS)

    Zebulum, Ricardo S.; Ramesham, Rajeshuni; Stoica, Adrian; Keymeulen, Didier; Daud, Taher; Sekanina, Lukas

    2005-01-01

    This paper describes an initial experiment performed to assess the electrical behavior of the Innovative Integration board containing a Digital Signal Processor (DSP) with its JTAG (Blackhawk) connector at low temperatures. The objective of the experiment is to determine the lowest temperature at which the DSP can operate. The DSP was tested at various low-temperatures and a Genetic Algorithm was used as the DSP test program.

  1. 40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... cycle statistics and compare with the established criteria as specified in 40 CFR 1065.514 to confirm...) Operate the engine for the first 180 seconds of the appropriate duty cycle, then allow it to idle without.... For example, if an engine starting at room temperature warms up enough in three minutes to...

  2. Estimation of the biphasic property in a female's menstrual cycle from cutaneous temperature measured during sleep.

    PubMed

    Chen, Wenxi; Kitazawa, Masumi; Togawa, Tatsuo

    2009-09-01

    This paper proposes a method to estimate a woman's menstrual cycle based on the hidden Markov model (HMM). A tiny device was developed that attaches around the abdominal region to measure cutaneous temperature at 10-min intervals during sleep. The measured temperature data were encoded as a two-dimensional image (QR code, i.e., quick response code) and displayed in the LCD window of the device. A mobile phone captured the QR code image, decoded the information and transmitted the data to a database server. The collected data were analyzed by three steps to estimate the biphasic temperature property in a menstrual cycle. The key step was an HMM-based step between preprocessing and postprocessing. A discrete Markov model, with two hidden phases, was assumed to represent higher- and lower-temperature phases during a menstrual cycle. The proposed method was verified by the data collected from 30 female participants, aged from 14 to 46, over six consecutive months. By comparing the estimated results with individual records from the participants, 71.6% of 190 menstrual cycles were correctly estimated. The sensitivity and positive predictability were 91.8 and 96.6%, respectively. This objective evaluation provides a promising approach for managing premenstrual syndrome and birth control. PMID:19551509

  3. Timing of the diurmal temperature cycle in remote sensing and model

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper investigates the structural difference in timing of the diurnal temperature cycle (DTC) over land resulting from variations in measuring devise or model framework. It is shown that the timing can be reliably estimated from temporally sparse observations acquired from a constellation of lo...

  4. Field Test of Boiler Primary Loop Temperature Controller

    SciTech Connect

    Glanville, P.; Rowley, P.; Schroeder, D.; Brand, L.

    2014-09-01

    Beyond these initial system efficiency upgrades are an emerging class of Advanced Load Monitoring (ALM) aftermarket controllers that dynamically respond to the boiler load, with claims of 10% to 30% of fuel savings over a heating season. For hydronic boilers specifically, these devices perform load monitoring, with continuous measurement of supply and in some cases return water temperatures. Energy savings from these ALM controllers are derived from dynamic management of the boiler differential, where a microprocessor with memory of past boiler cycles prevents the boiler from firing for a period of time, to limit cycling losses and inefficient operation during perceived low load conditions. These differ from OTR controllers, which vary boiler setpoint temperatures with ambient conditions while maintaining a fixed differential. PARR installed and monitored the performance of one type of ALM controller, the M2G from Greffen Systems, at multifamily sites in the city of Chicago and its suburb Cary, IL, both with existing OTR control. Results show that energy savings depend on the degree to which boilers are over-sized for their load, represented by cycling rates. Also savings vary over the heating season with cycling rates, with greater savings observed in shoulder months. Over the monitoring period, over-sized boilers at one site showed reductions in cycling and energy consumption in line with prior laboratory studies, while less over-sized boilers at another site showed muted savings.

  5. Gas Generation Testing of Neptunium Oxide at Elevated Temperature

    SciTech Connect

    Duffey, JM

    2004-01-30

    Elevated temperature gas generation tests have been conducted using neptunium dioxide produced on a laboratory scale using the HB-Line Phase II flowsheet. These tests were performed to determine what effect elevated temperatures would have on the neptunium dioxide in comparison to neptunium dioxide tested at ambient temperature. The headspace gas compositions following storage at elevated temperatures associated with normal conditions of transport (NCT) have been measured. These test results show an increase in hydrogen generation rate at elevated temperature and significant removal of oxygen from the headspace gas. The elevated temperature gas generation tests described in this report involved heating small test vessels containing neptunium dioxide and measuring the headspace gas pressure and composition at the end of the test period. Four samples were used in these tests to evaluate the impact of process variables on the gas generation rate. Two samples were calcined to 600 degrees Celsius and two were calcined to 650 degrees Celsius. Each test vessel contained approximately 9.5 g of neptunium dioxide. Following exposure to 75 per cent relative humidity (RH) for five days, these samples were loaded in air and then heated to between 105 and 115 degrees Celsius for about one month. At the conclusion of the test period, the headspace gas of each container was analyzed using a micro-gas chromatograph installed in the glovebox where the experiments were conducted. The pressure, volume, and composition data for the headspace gas samples were used to calculate average H2 generation rates.

  6. The effect of skin temperature on performance during a 7.5-km cycling time trial.

    PubMed

    Levels, Koen; de Koning, Jos J; Foster, Carl; Daanen, Hein A M

    2012-09-01

    Aerobic exercise performance is seriously compromised in the heat. Possibly, a high skin temperature causes a rating of perceived exertion (RPE)-mediated decrease in exercise intensity. The purpose of this study was to determine the effect of skin temperature on power output during a 7.5-km cycling time trial. Thirteen well-trained male subjects performed a 7.5-km cycling time trial at 15°C and 50% relative humidity (CONTROL), with radiative heat stress during the time trial, and with (PRECOOL) or without (HEAT) precooling. Heat stress was applied by infrared heaters positioned in front of the cycle ergometer between 1.5 and 6.0 km. Skin, rectal, and pill temperature, power output, heart rate, and RPE were measured during the trial. Despite the lower mean skin temperature at the start of the time trial for PRECOOL compared to HEAT (-2.1 ± 0.7°C; P < 0.01) and CONTROL (-1.8 ± 0.6°C; P < 0.05), and a greater increase in mean skin temperature during the heat stress period for PRECOOL (4.5 ± 1.0°C) and HEAT (3.9 ± 0.8°C) than for CONTROL (-0.3 ± 0.6°C; P < 0.01), no differences in power output were found between HEAT (273 ± 45 W) and CONTROL (284 ± 43 W; P = 0.11) and between HEAT and PRECOOL (266 ± 50 W; P = 0.47). Power output during the time trial was greater for CONTROL than for PRECOOL (P < 0.05). Additionally, no differences were observed in core temperature measures, HR, and RPE. Skin temperature does not affect the selection and modulation of exercise intensity in a 7.5-km cycling time trial. PMID:22270485

  7. ON THE CONSTANCY OF THE ELECTRON TEMPERATURE IN THE EXPANDING CORONA THROUGHOUT SOLAR CYCLE 23

    SciTech Connect

    Habbal, Shadia Rifai; Morgan, Huw; Druckmueller, Miloslav; Ding, Adalbert

    2010-03-10

    A recent analysis of Fe emission lines observed during the total solar eclipses of 2006 March 29 and 2008 August 1 established the first empirical link between the electron temperature in the expanding corona and Fe charge states measured in interplanetary space. In this Letter, we use this link to infer this temperature throughout solar cycle 23 from in situ charge state measurements from the Solar Wind Ion Composition Spectrometer (SWICS) on the Advanced Composition Explorer (ACE) and on Ulysses. The distribution of the SWICS/ACE Fe charge states, which span cycle 23 from 1998 to 2009, is skewed with a peak centered on Fe{sup 8+}, Fe{sup 9+}, and Fe{sup 10+} and a tail spanning Fe{sup 12+} to Fe{sup 20+}. An iterative process based on this distribution and on the Fe ion fraction as a function of electron temperature yields a narrow peak at 1.1 x 10{sup 6} K. The tail in the measured charge state distribution is attributed to the sporadic release of material hotter than 2 x 10{sup 6} K from closed magnetic structures within the bulges of streamers. The Fe Ulysses charge state measurements between 1992 and 1997 from cycle 22 peaked at Fe{sup 11+}, indicative of a slightly higher temperature of 1.5 x 10{sup 6} K. The relative constancy of the electron temperature in the expanding corona throughout solar cycle 23 points to the presence of an unknown mechanism regulating the energy input to electrons in the acceleration region of the solar wind at all latitudes during this cycle.

  8. Low Temperature Creep of Hot-Extruded Near-Stoichiometric NiTi Shape Memory Alloy. Part 2; Effect of Thermal Cycling

    NASA Technical Reports Server (NTRS)

    Raj, S. V.; Noebe, R. D.

    2013-01-01

    This paper is the first report on the effect prior low temperature creep on the thermal cycling behavior of NiTi. The isothermal low temperature creep behavior of near-stoichiometric NiTi between 300 and 473 K was discussed in Part I. The effect of temperature cycling on its creep behavior is reported in the present paper (Part II). Temperature cycling tests were conducted between either 300 or 373 K and 473 K under a constant applied stress of either 250 or 350 MPa with hold times lasting at each temperature varying between 300 and 700 h. Each specimen was pre-crept either at 300 or at 473 K for several months under an identical applied stress as that used in the subsequent thermal cycling tests. Irrespective of the initial pre-crept microstructures, the specimens exhibited a considerable increase in strain with each thermal cycle so that the total strain continued to build-up to 15 to 20 percent after only 5 cycles. Creep strains were immeasurably small during the hold periods. It is demonstrated that the strains in the austenite and martensite are linearly correlated. Interestingly, the differential irrecoverable strain, in the material measured in either phase decreases with increasing number of cycles, similar to the well-known Manson-Coffin relation in low cycle fatigue. Both phases are shown to undergo strain hardening due to the development of residual stresses. Plots of true creep rate against absolute temperature showed distinct peaks and valleys during the cool-down and heat-up portions of the thermal cycles, respectively. Transformation temperatures determined from the creep data revealed that the austenitic start and finish temperatures were more sensitive to the pre-crept martensitic phase than to the pre-crept austenitic phase. The results are discussed in terms of a phenomenological model, where it is suggested that thermal cycling between the austenitic and martensitic phase temperatures or vice versa results in the deformation of the austenite and

  9. POWER CYCLE AND STRESS ANALYSES FOR HIGH TEMPERATURE GAS-COOLED REACTOR

    SciTech Connect

    Oh, Chang H; Davis, Cliff; Hawkes, Brian D; Sherman, Steven R

    2007-05-01

    The Department of Energy and the Idaho National Laboratory are developing a Next Generation Nuclear Plant (NGNP) to serve as a demonstration of state-of-the-art nuclear technology. The purpose of the demonstration is two fold 1) efficient low cost energy generation and 2) hydrogen production. Although a next generation plant could be developed as a single-purpose facility, early designs are expected to be dual-purpose. While hydrogen production and advanced energy cycles are still in its early stages of development, research towards coupling a high temperature reactor, electrical generation and hydrogen production is under way. Many aspects of the NGNP must be researched and developed in order to make recommendations on the final design of the plant. Parameters such as working conditions, cycle components, working fluids, and power conversion unit configurations must be understood. Three configurations of the power conversion unit were demonstrated in this study. A three-shaft design with three turbines and four compressors, a combined cycle with a Brayton top cycle and a Rankine bottoming cycle, and a reheated cycle with three stages of reheat were investigated. An intermediate heat transport loop for transporting process heat to a High Temperature Steam Electrolysis (HTSE) hydrogen production plant was used. Helium, CO2, and a 80% nitrogen, 20% helium mixture (by weight) were studied to determine the best working fluid in terms cycle efficiency and development cost. In each of these configurations the relative component size were estimated for the different working fluids. The relative size of the turbomachinery was measured by comparing the power input/output of the component. For heat exchangers the volume was computed and compared. Parametric studies away from the baseline values of the three-shaft and combined cycles were performed to determine the effect of varying conditions in the cycle. This gives some insight into the sensitivity of these cycles to

  10. Environmental degradation of 316 stainless steel in high temperature low cycle fatigue

    NASA Technical Reports Server (NTRS)

    Kalluri, Sreeramesh; Manson, S. Stanford; Halford, Gary R.

    1987-01-01

    Procedures based on modification of the conventional Strainrange Partitioning method are proposed to characterize the time-dependent degradation of engineering alloys in high-temperature, low-cycle fatigue. Creep-fatigue experiments were conducted in air using different waveforms of loading on 316 stainless steel at 816 C (1500 F) to determine the effect of exposure time on cyclic life. Reductions in the partitioned cyclic lives were observed with an increase in the time of exposure (or with the corresponding decrease in the steady-state creep rate) for all the waveforms involving creep strain. Excellent correlations of the experimental data were obtained by modifying the Conventional Strainrange Partitioning life relationships involving creep strain using a power-law term of either: (1) time of exposure, or (2) steady-state creep rate of the creep-fatigue test. Environmental degradation due to oxidation, material degradation due to the precipitation of carbides along the grain boundaries and detrimental deformation modes associated with the prolonged periods of creep were observed to be the main mechanisms responsible for life reductions at long exposure times.

  11. 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.

  12. High cycle fatigue behavior of Incoloy 800H in a simulated high-temperature gas-cooled reactor helium environment

    SciTech Connect

    Soo, P.; Sabatini, R.L.; Epel, L.G.; Hare, J.R. Sr.

    1980-01-01

    The current study was an attempt to evaluate the high cycle fatigue strength of Incoloy 800H in a High-Temperature Gas-Cooled Reactor helium environment containing significant quantities of moisture. As-heat-treated and thermally-aged materials were tested to determine the effects of long term corrosion in the helium test gas. Results from in-helium tests were compared to those from a standard air environment. It was found that the mechanisms of fatigue failure were very complex and involved recovery/recrystallization of the surface ground layer on the specimens, sensitization, hardness changes, oxide scale integrity, and oxidation at the tips of propagation cracks. For certain situations a corrosion-fatigue process seems to be controlling. However, for the helium environment studied, there was usually no aging or test condition for which air gave a higher fatigue strength.

  13. Mechanisms of deformation and fracture in high temperature low cycle fatigue of Rene 80 and IN 100

    NASA Technical Reports Server (NTRS)

    Romanoski, G. R., Jr.

    1982-01-01

    Specimens tested for the AGARD strain range partitioning program were investigated. Rene 80 and IN 100 were tested in air and in vacuum; at 871 C, 925 C, and 1000 C; and in the coated and uncoated condition. The specimens exhibited a multiplicity of high-temperature low-cycle fatigue damage. Observations of the various forms of damage were consistent with material and testing conditions and were generally in agreement with previous studies. In every case observations support a contention that failure occurs at a particular combination of crack length and maximum stress. A failure criterion which is applicable in the regime of testing studied is presented. The predictive capabilities of this criterion are straight forward.

  14. 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.

  15. Inhomogeneous degradation of graphite anodes in automotive lithium ion batteries under low-temperature pulse cycling conditions

    NASA Astrophysics Data System (ADS)

    Burow, Daniel; Sergeeva, Kseniya; Calles, Simon; Schorb, Klaus; Börger, Alexander; Roth, Christina; Heitjans, Paul

    2016-03-01

    The aging of graphite anodes in prismatic lithium ion cells during a low temperature pulse charging regime was studied by electrical tests and post-mortem analysis. The capacity decrease and impedance increase mainly occurs in the beginning of cycling and lithium plating was identified as the major aging mechanism. The degradation and the local states of charge show an inhomogeneous distribution over the anode, which is confirmed from spatially resolved XRD studies and SEM combined with EDX performed on electrode cross sections. Comparing a charged cell with a discharged cell reveals that ca. 1/3 of the lithium is plated reversibly at the given SOH of 60%. It is proposed that high charge rates at low temperatures induce inhomogeneities of temperature and anode utilization resulting in inhomogeneous aging effects that accumulate over lifetime.

  16. Calibration and testing or models of the global carbon cycle

    SciTech Connect

    Emanuel, W.R.; Killough, G.G.; Shugart, H.H. Jr.

    1980-01-01

    A ten-compartment model of the global biogeochemical cycle of carbon is presented. The two less-abundant isotopes of carbon, /sup 13/C and /sup 14/C, as well as total carbon, are considered. The cycling of carbon in the ocean is represented by two well-mixed compartments and in the world's terrestrial ecosystems by seven compartments, five which are dynamic and two with instantaneous transfer. An internally consistent procedure for calibrating this model against an assumed initial steady state is discussed. In particular, the constraint that the average /sup 13/C//sup 12/C ratio in the total flux from the terrestrial component of the model to the atmosphere be equal to that of the steady-state atmosphere is investigated. With this additional constraint, the model provides a more accurate representation of the influence of the terrestrial system on the /sup 13/C//sup 12/C ratio of the atmosphere and provides an improved basis for interpreting records, such as tree rings, reflecting historical changes in this ratio.

  17. Testing the Goodwin growth-cycle macroeconomic dynamics in Brazil

    NASA Astrophysics Data System (ADS)

    Moura, N. J.; Ribeiro, Marcelo B.

    2013-05-01

    This paper discusses the empirical validity of Goodwin’s (1967) macroeconomic model of growth with cycles by assuming that the individual income distribution of the Brazilian society is described by the Gompertz-Pareto distribution (GPD). This is formed by the combination of the Gompertz curve, representing the overwhelming majority of the population (˜99%), with the Pareto power law, representing the tiny richest part (˜1%). In line with Goodwin’s original model, we identify the Gompertzian part with the workers and the Paretian component with the class of capitalists. Since the GPD parameters are obtained for each year and the Goodwin macroeconomics is a time evolving model, we use previously determined, and further extended here, Brazilian GPD parameters, as well as unemployment data, to study the time evolution of these quantities in Brazil from 1981 to 2009 by means of the Goodwin dynamics. This is done in the original Goodwin model and an extension advanced by Desai et al. (2006). As far as Brazilian data is concerned, our results show partial qualitative and quantitative agreement with both models in the studied time period, although the original one provides better data fit. Nevertheless, both models fall short of a good empirical agreement as they predict single center cycles which were not found in the data. We discuss the specific points where the Goodwin dynamics must be improved in order to provide a more realistic representation of the dynamics of economic systems.

  18. The application of probabilistic design theory to high temperature low cycle fatigue

    NASA Technical Reports Server (NTRS)

    Wirsching, P. H.

    1981-01-01

    Metal fatigue under stress and thermal cycling is a principal mode of failure in gas turbine engine hot section components such as turbine blades and disks and combustor liners. Designing for fatigue is subject to considerable uncertainty, e.g., scatter in cycles to failure, available fatigue test data and operating environment data, uncertainties in the models used to predict stresses, etc. Methods of analyzing fatigue test data for probabilistic design purposes are summarized. The general strain life as well as homo- and hetero-scedastic models are considered. Modern probabilistic design theory is reviewed and examples are presented which illustrate application to reliability analysis of gas turbine engine components.

  19. Studies on three-temperature, three-cylinder Stirling cycle machine (accuracy of vector analysis)

    SciTech Connect

    Ohtomo, Michihiro; Isshiki, Naotsugu; Watanabe, Hiroichi

    1996-12-31

    A Simple vector analysis method aimed to quickly determine the performance of complicated multi-cylinder Stirling cycle machines such as the Vuilleumier cycle machine was introduced by the authors in 1992. It has proven to be a very simple graphic method for the design and analysis of future complicated Stirling cycle machines. In this method, it is assumed that all volume variations and pressure changes are sinusoidal. Actually all volume fluctuations can be assumed to be sinusoidal without large errors, but pressure fluctuation deviates from sinusoidal assumptions, because pressure is a reciprocal of the total sinusoidal volume fluctuation. The pressure value estimated by this vector analysis method is compared to the exact calculation, and the error is calculated and discussed. It is known that the error depends on the pressure ratio and the dead volume ratio, and the error is less than 10% in many cases. The features and details of a newly made experimental, small, pressurized (6MPa) three-temperature (hot, cold and middle temperature), three-cylinder Stirling cycle machine are described. This machine was basically designed by this vector analysis method. This machine can work as a cooler and/or a heat pump, by adjusting the phase angle of the hot cylinder and depending upon whether motor power and/or heat input is supplied. Rotating vector analysis was done on a free piston or a pulse tube machine (Storch, 1988), but this report gives new convenient methods for complicated Stirling cycle systems.

  20. The role of sea ice in the temperature-precipitation feedback of glacial cycles

    NASA Astrophysics Data System (ADS)

    Gildor, Hezi; Ashkenazy, Yosef; Tziperman, Eli; Lev, Ilit

    2014-08-01

    The response of the hydrological cycle to climate variability and change is a critical open question, where model reliability is still unsatisfactory, yet upon which past climate history can shed some light. Sea ice is a key player in the climate system and in the hydrological cycle, due to its strong albedo effect and its insulating effect on local evaporation and air-sea heat flux. Using an atmospheric general circulation model with specified sea surface temperature and sea-ice distribution, the role of sea ice in the hydrological cycle is investigated under last glacial maximum (LGM) and present day conditions, and by studying its contribution to the "temperature-precipitation feedback". By conducting a set of sensitivity experiments in which the albedo and thickness of the sea ice are varied, the various effects of sea ice in the hydrological cycle are isolated. It is demonstrated that for a cold LGM like state, a warmer climate (as a result of reduced sea-ice cover) leads to an increase in snow precipitation over the ice sheets. The insulating effect of the sea ice on the hydrological cycle is found to be larger than the albedo effect. These two effects interact in a nonlinear way and their total effect is not equal to summing their separate contribution.

  1. Residual thermal effects in macro fiber composite actuators exposed to persistent temperature cycling

    NASA Astrophysics Data System (ADS)

    Hobeck, J. D.; Owen, R. B.; Inman, D. J.

    2016-03-01

    In this letter, the authors present results of an experimental investigation demonstrating how extreme persistent thermal cycling influences the performance of piezoelectric macro fiber composite (MFC) actuators. More specifically, this research shows how repeated temperature cycling ranging from -60 °C to 90 °C and from -50 °C to 150 °C affects an MFCs ability to actuate while being driven at frequencies of 60 Hz to 90 Hz with a voltage of 20 Vpp. Experimental results show that thermal cycling causes MFC actuation characteristics to drift and eventually stabilize after approximately 20 cycles. In two cases presented here, thermal cycling alone caused a residual increase in actuation amplitude that exceeded the initial amplitude by 70%. This apparent thermal memory effect of MFCs may significantly impact the design and analysis of active structures where MFCs are used for vibration or displacement control in transient extreme temperature environments such as those encountered by aerospace structures, industrial equipment, automobiles, and civil infrastructure.

  2. 40 CFR 91.410 - Engine test cycle.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test Procedures § 91.410 Engine... conditions. Such deviations shall not exceed 10 percent of the maximum torque at the test speed. The minimum... idle speed, whichever is greater. For direct drive products (no neutral gear), it is acceptable to...

  3. 40 CFR 91.410 - Engine test cycle.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES Gaseous Exhaust Test Procedures § 91.410 Engine... conditions. Such deviations shall not exceed 10 percent of the maximum torque at the test speed. The minimum... idle speed, whichever is greater. For direct drive products (no neutral gear), it is acceptable to...

  4. Flexible thermal cycle test equipment for concentrator solar cells

    DOEpatents

    Hebert, Peter H.; Brandt, Randolph J.

    2012-06-19

    A system and method for performing thermal stress testing of photovoltaic solar cells is presented. The system and method allows rapid testing of photovoltaic solar cells under controllable thermal conditions. The system and method presents a means of rapidly applying thermal stresses to one or more photovoltaic solar cells in a consistent and repeatable manner.

  5. 40 CFR 86.1333-2010 - Transient test cycle generation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... CFR part 1065. (2) Torque is normalized to the maximum torque at the rpm listed with it. Therefore, to.... The generation of the maximum torque curve is described in 40 CFR part 1065. (b) Example of the... engines: ER13JY05.001 Where: MaxTestSpeed = the maximum test speed as calculated in 40 CFR part 1065....

  6. 40 CFR 86.1333-2010 - Transient test cycle generation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CFR part 1065. (2) Torque is normalized to the maximum torque at the rpm listed with it. Therefore, to.... The generation of the maximum torque curve is described in 40 CFR part 1065. (b) Example of the... engines: ER13JY05.001 Where: MaxTestSpeed = the maximum test speed as calculated in 40 CFR part 1065....

  7. 40 CFR 86.1333-2010 - Transient test cycle generation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... CFR part 1065. (2) Torque is normalized to the maximum torque at the rpm listed with it. Therefore, to.... The generation of the maximum torque curve is described in 40 CFR part 1065. (b) Example of the... engines: ER13JY05.001 Where: MaxTestSpeed = the maximum test speed as calculated in 40 CFR part 1065....

  8. A study of the nycthemeral cycle of behavioural temperature regulation in man.

    PubMed Central

    Cabanac, M; Hildebrandt, G; Massonnet, B; Strempel, H

    1976-01-01

    1. Four human subjects were rendered hyperthermic and hypothermic by immersion in warm and cool water, at 02.00, 08.00, 14.00 and 20.00 hr. Bath and oesophageal temperatures and pulse rate were recorded. Temperature preference was determined by operant behaviour and vote. The core temperature set-point for behavioural thermoregulation was estimated from the behavioural results. 2. The results are in accord with those of previous studies of the nyethemeral cycling of autonomic responsiveness to heat and cold with a heating up phase before noon and a cooling down phase during the early night. 3. Subjective sensations and behavioural responses were also found to follow a nycthemeral cycle with a minimum before noon and a maximum at 20.00 hr. 4. The core temperature set point was 0-7 degrees C higher after noon than before noon with a small phase advance from resting core temperature. This result suggests that the nycthemeral cyclic change in body temperature is due to a nycthemeral cyclic change in the set-point near to which body temperature is kept by both autonomic and behavioural thermoregulatory responses. PMID:985881

  9. Cyclic performance tests of Sn/MWCNT composite lithium ion battery anodes at different temperatures

    NASA Astrophysics Data System (ADS)

    Tocoglu, U.; Cevher, O.; Akbulut, H.

    2016-04-01

    In this study tin-multi walled carbon nanotube (Sn-MWCNT) lithium ion battery anodes were produced and their electrochemical galvanostatic charge/discharge tests were conducted at various (25 °C, 35 °C, 50 °C) temperatures to determine the cyclic behaviors of anode at different temperatures. Anodes were produced via vacuum filtration and DC magnetron sputtering technique. Tin was sputtered onto buckypapers to form composite structure of anodes. SEM analysis was conducted to determine morphology of buckypapers and Sn-MWCNT composite anodes. Structural and phase analyses were conducted via X-ray diffraction and Raman Spectroscopy technique. CR2016 coin cells were assembled for electrochemical tests. Cyclic voltammetry test were carried out to determine the reversibility of reactions between anodes and reference electrode between 0.01-2.0 V potential window. Galvanostatic charge/discharge tests were performed to determine cycle performance of anodes at different temperatures.

  10. Analyses of mixed-hydrocarbon binary thermodynamic cycles for moderate-temperature geothermal resources

    SciTech Connect

    Demuth, O.J.

    1981-02-01

    A number of binary geothermal cycles utilizing mixed hydrocarbon working fluids were analyzed with the overall objective of finding a working fluid which can produce low-cost electrical energy using a moderately-low temperature geothermal resource. Both boiling and supercritical shell-and-tube cycles were considered. The performance of a dual-boiling isobutane cycle supplied by a 280/sup 0/F hydrothermal resource (corresponding to the 5 MW pilot plant at the Raft River site in Idaho) was selected as a reference. To investigate the effect of resource temperature on the choice of working fluid, several analyses were conducted for a 360/sup 0/F hydrothermal resource, which is representative of the Heber resource in California. The hydrocarbon working fluids analyzed included methane, ethane, propane, isobutane, isopentane, hexane, heptane, and mixtures of those pure hydrocarbons. For comparison, two fluorocarbon refrigerants were also analyzed. These fluorocarbons, R-115 and R-22, were suggested as resulting in high values of net plant geofluid effectiveness (watt-hr/lbm geofluid) at the two resource temperatures chosen for the study. Preliminary estimates of relative heat exchanger size (product of overall heat transfer coefficient times heater surface area) were made for a number of the better performing cycles.

  11. 30 CFR 7.47 - Deflection temperature test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Deflection temperature test. 7.47 Section 7.47 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.47...

  12. 30 CFR 7.47 - Deflection temperature test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Deflection temperature test. 7.47 Section 7.47 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS TESTING BY APPLICANT OR THIRD PARTY Battery Assemblies § 7.47...

  13. A high temperature testing system for ceramic composites

    NASA Technical Reports Server (NTRS)

    Hemann, John

    1994-01-01

    Ceramic composites are presently being developed for high temperature use in heat engine and space power system applications. The operating temperature range is expected to be 1090 to 1650 C (2000 F to 3000 F). Very little material data is available at these temperatures and, therefore, it is desirable to thoroughly characterize the basic unidirectional fiber reinforced ceramic composite. This includes testing mainly for mechanical material properties at high temperatures. The proper conduct of such characterization tests requires the development of a tensile testing system includes unique gripping, heating, and strain measuring devices which require special considerations. The system also requires an optimized specimen shape. The purpose of this paper is to review various techniques for measuring displacements or strains, preferably at elevated temperatures. Due to current equipment limitations it is assumed that the specimen is to be tested at a temperature of 1430 C (2600F) in an oxidizing atmosphere. For the most part, previous high temperature material characterization tests, such as flexure and tensile tests, have been performed in inert atmospheres. Due to the harsh environment in which the ceramic specimen is to be tested, many conventional strain measuring techniques can not be applied. Initially a brief description of the more commonly used mechanical strain measuring techniques is given. Major advantages and disadvantages with their application to high temperature tensile testing of ceramic composites are discussed. Next, a general overview is given for various optical techniques. Advantages and disadvantages which are common to these techniques are noted. The optical methods for measuring strain or displacement are categorized into two sections. These include real-time techniques. Finally, an optical technique which offers optimum performance with the high temperature tensile testing of ceramic composites is recommended.

  14. Ignition and Performance Tests of Rocket-Based Combined Cycle Propulsion System

    NASA Technical Reports Server (NTRS)

    Anderson, William E.

    2005-01-01

    The ground testing of a Rocket Based Combined Cycle engine implementing the Simultaneous Mixing and Combustion scheme was performed at the direct-connect facility of Purdue University's High Pressure Laboratory. The fuel-rich exhaust of a JP-8/H2O2 thruster was mixed with compressed, metered air in a constant area, axisymmetric duct. The thruster was similar in design and function to that which will be used in the flight test series of Dryden's Ducted-Rocket Experiment. The determination of duct ignition limits was made based on the variation of secondary air flow rates and primary thruster equivalence ratios. Thrust augmentation and improvements in specific impulse were studied along with the pressure and temperature profiles of the duct to study mixing lengths and thermal choking. The occurrence of ignition was favored by lower rocket equivalence ratios. However, among ignition cases, better thrust and specific impulse performance were seen with higher equivalence ratios owing to the increased fuel available for combustion. Thrust and specific impulse improvements by factors of 1.2 to 1.7 were seen. The static pressure and temperature profiles allowed regions of mixing and heat addition to be identified. The mixing lengths were found to be shorter at lower rocket equivalence ratios. Total pressure measurements allowed plume-based calculation of thrust, which agreed with load-cell measured values to within 6.5-8.0%. The corresponding Mach Number profile indicated the flow was not thermally choked for the highest duct static pressure case.

  15. The cycle life chemistry of ambient-temperature secondary lithium cells

    NASA Technical Reports Server (NTRS)

    Somoano, R.; Carter, B. J.; Subba Rao, S.; Shen, D.; Yen, S. P. S.

    1985-01-01

    The Jet Propulsion Laboratory is involved in a NASA-sponsored research program to demonstrate the feasibility of ambient-temperature secondary lithium batteries for geosynchronous space applications. Encouraging cycle life has been demonstrated in sealed, cathode-limited laboratory cells. However, the cell capacity declines with cycle life. The results of recent studies of the lithium electrode passivation chemistry, and of conductive diluents for TiS2 cathodes and their possible contribution to capacity decline, are here presented. Technical issues associated with the unique operational requirements of a geosynchronous mission are also described.

  16. Ultrahigh vacuum, high temperature, low cycle fatigue of coated and uncoated Rene 80

    NASA Technical Reports Server (NTRS)

    Kortovich, C. S.

    1976-01-01

    A study was conducted on the ultrahigh vacuum strain controlled by low cycle fatigue behavior of uncoated and CODEP B-1 aluminide coated Rene' 80 nickel-base superalloy at 1000 C (1832 F) and 871 C (1600 F). The results indicated little effect of coating or temperature on the fatigue properties. There was, however, a significant effect on fatigue life when creep was introduced into the strain cycles. The effect of this creep component was analyzed in terms of the method of strainrange partitioning.

  17. 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.

  18. Testing of a Miniature Loop Heat Pipe Using a Thermal Electrical Cooler for Temperature Control

    NASA Technical Reports Server (NTRS)

    Ku, Jentung; Jeong, Soeng-II; Butler, Dan

    2004-01-01

    This paper describes the design and testing of a miniature LHP having a 7 mm O.D. evaporator with an integral CC. The vapor line and liquid line are made of 1.6mm stainless steel tubing. The evaporator and the CC are connected on the outer surface by a copper strap and a thermoelectric (TEC) is installed on the strap. The TEC is used to control the CC temperature by applying an electrical current for heating or cooling. Tests performed in ambient included start-up, power cycle, sink temperature cycle, and CC temperature control using TEC. The LHP demonstrated very robust operation in all tests where the heat load varied between 0.5W and 1OOW, and the sink temperature varied between 243K and 293K. The heat leak from the evaporator to the CC was extremely small. The TEC was able to control the CC temperature within +/-0.3K under all test conditions, and the required control heater power was less than 1W.

  19. Highly Variable Cycle Exhaust Model Test (HVC10)

    NASA Technical Reports Server (NTRS)

    Henderson, Brenda; Wernet, Mark; Podboy, Gary; Bozak, Rick

    2010-01-01

    Results from acoustic and flow-field studies using the Highly Variable Cycle Exhaust (HVC) model were presented. The model consisted of a lobed mixer on the core stream, an elliptic nozzle on the fan stream, and an ejector. For baseline comparisons, the fan nozzle was replaced with a round nozzle and the ejector doors were removed from the model. Acoustic studies showed far-field noise levels were higher for the HVC model with the ejector than for the baseline configuration. Results from Particle Image Velocimetry (PIV) studies indicated that large flow separation regions occurred along the ejector doors, thus restricting flow through the ejector. Phased array measurements showed noise sources located near the ejector doors for operating conditions where tones were present in the acoustic spectra.

  20. Test summary for advanced H2 cycle NI-CD cell

    NASA Technical Reports Server (NTRS)

    Miller, Lee

    1987-01-01

    To improve operational tolerances and mass, the H2 gas recombination design provisions of the Ni-H2 system were incorporated into the sealed Ni-Cd system. Produced is a cell design capable of operating on the H2 cycle versus the normal O2 cycle. Three test cells have now completed approximately 4,330 LEO (90 minute) cycles at 20 percent depth of discharge (DOD). Performance remains stable although one cell exhibited a temporary pressure anomaly.

  1. High temperature abatement of acid gases from waste incineration. Part II: Comparative life cycle assessment study

    SciTech Connect

    Biganzoli, Laura; Racanella, Gaia; Marras, Roberto; Rigamonti, Lucia

    2015-01-15

    Highlights: • Two scenarios of acid gases removal in WTE plants were compared in an LCA study. • A detailed inventory based on primary data has been reported for the production of the new dolomitic sorbent. • Results show that the comparison between the two scenarios does not show systematic differences. • The potential impacts are reduced only if there is an increase in the energy efficiency of the WTE plant. - Abstract: The performances of a new dolomitic sorbent, named Depurcal®MG, to be directly injected at high temperature in the combustion chamber of Waste-To-Energy (WTE) plants as a preliminary stage of deacidification, were experimentally tested during full-scale commercial operation. Results of the experimentations were promising, and have been extensively described in Biganzoli et al. (2014). This paper reports the Life Cycle Assessment (LCA) study performed to compare the traditional operation of the plants, based on the sole sodium bicarbonate feeding at low temperature, with the new one, where the dolomitic sorbent is injected at high temperature. In the latter the sodium bicarbonate is still used, but at lower rate because of the decreased load of acid gases entering the flue gas treatment line. The major goal of the LCA was to make sure that a burden shifting was not taking place somewhere in the life cycle stages, as it might be the case when a new material is used in substitution of another one. According to the comparative approach, only the processes which differ between the two operational modes were included in the system boundaries. They are the production of the two reactants and the treatment of the corresponding solid residues arising from the neutralisation of acid gases. The additional CO{sub 2} emission at the stack of the WTE plant due to the activation of the sodium bicarbonate was also included in the calculation. Data used in the modelling of the foreground system are primary, derived from the experimental tests described in

  2. Temperature and Cyanobacterial Bloom Biomass Influence Phosphorous Cycling in Eutrophic Lake Sediments

    PubMed Central

    Chen, Mo; Ye, Tian-Ran; Krumholz, Lee R.; Jiang, He-Long

    2014-01-01

    Cyanobacterial blooms frequently occur in freshwater lakes, subsequently, substantial amounts of decaying cyanobacterial bloom biomass (CBB) settles onto the lake sediments where anaerobic mineralization reactions prevail. Coupled Fe/S cycling processes can influence the mobilization of phosphorus (P) in sediments, with high releases often resulting in eutrophication. To better understand eutrophication in Lake Taihu (PRC), we investigated the effects of CBB and temperature on phosphorus cycling in lake sediments. Results indicated that added CBB not only enhanced sedimentary iron reduction, but also resulted in a change from net sulfur oxidation to sulfate reduction, which jointly resulted in a spike of soluble Fe(II) and the formation of FeS/FeS2. Phosphate release was also enhanced with CBB amendment along with increases in reduced sulfur. Further release of phosphate was associated with increases in incubation temperature. In addition, CBB amendment resulted in a shift in P from the Fe-adsorbed P and the relatively unreactive Residual-P pools to the more reactive Al-adsorbed P, Ca-bound P and organic-P pools. Phosphorus cycling rates increased on addition of CBB and were higher at elevated temperatures, resulting in increased phosphorus release from sediments. These findings suggest that settling of CBB into sediments will likely increase the extent of eutrophication in aquatic environments and these processes will be magnified at higher temperatures. PMID:24682039

  3. Development of a low cost, low temperature cryocooler using the Gifford McMahon cycle

    NASA Astrophysics Data System (ADS)

    Ramanayaka, A.; Mani, R.

    2008-03-01

    Although Helium is the second most abundant element, its concentration in the earth's atmosphere is fairly low and constant, as the portion that escapes from the atmosphere is replace by new emission. Historically, Helium was extracted as a byproduct of natural gas production, and stored in gas fields in a National Helium Reserve, in an attempt to conserve this interesting element. National policy has changed and the cost of liquid Helium has increased rapidly in the recent past. These new circumstances have created new interest in alternative eco-friendly methods to realizing and maintaining low temperatures in the laboratory. There have been number of successful attempts at making low temperature closed cycle Helium refrigerators by modifying an existing closed cycle system, and usually the regenerator has been replaced in order to achieve the desired results. Here, we discus our attempt to fabricate a low cost, low temperature closed cycle Helium refrigerator starting from a 15K Gifford McMahon system. We reexamine the barriers to realizing lower temperature here and our attempts at overcoming them.

  4. Field Test of Boiler Primary Loop Temperature Controller

    SciTech Connect

    Glanville, P.; Rowley, P.; Schroeder, D.; Brand, L.

    2014-09-01

    Beyond these initial system efficiency upgrades are an emerging class of Advanced Load Monitoring (ALM) aftermarket controllers that dynamically respond to the boiler load, with claims of 10% to 30% of fuel savings over a heating season. For hydronic boilers specifically, these devices perform load monitoring, with continuous measurement of supply and, in some cases, return water temperatures. Energy savings from these ALM controllers are derived from dynamic management of the boiler differential, where a microprocessor with memory of past boiler cycles prevents the boiler from firing for a period of time, to limit cycling losses and inefficient operation during perceived low load conditions. These differ from OTR controllers, which vary boiler setpoint temperatures with ambient conditions while maintaining a fixed differential.

  5. 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.

  6. Assessment of external fixator reusability using load- and cycle-dependent tests.

    PubMed

    Matsuura, Maiko; Lounici, Smain; Inoue, Nozomu; Walulik, Stephen; Chao, Edmund Y S

    2003-01-01

    No standard method has been established for investigating repeated use of an external fixator. The purpose of the current study was to establish a fatigue testing method for assessing fixator frame reuse. A unilateral DynaFix trade mark external fixator system was tested using high-load and low-cycle (900-150 N at 5 Hz) and low-load and high-cycle (450-100 N at 10 Hz) tests (assumed one use of 500,000 and 1 million cycles, respectively). These loading conditions were selected to simulate single clinical use and to satisfy Food and Drug Administration requirements. In the high-load low-cycle test, substantial failure of the serrated joint occurred before completion of the first simulated use. In the low-load high-cycle test, all fixators completed three simulated clinical uses without failure, although (1/4) of the serrated joint components had hairline cracks. The high-load low-cycle test identified the fixator components which should be examined and replaced if reuse of the fixator is to be considered. Wear and deformation of the set screw on the rotary joint and telescoping mechanisms were observed in the low-load high-cycle test but not in the high-load low-cycle test. Therefore, if the unilateral DynaFix trade mark fixators are being considered for reusability, the number of reuses should be limited as the whole structure of the device will experience fatigue damage as the loading cycle increases. PMID:12579028

  7. Stability and corrosion testing of a high temperature phase change material for CSP applications

    NASA Astrophysics Data System (ADS)

    Liu, Ming; Bell, Stuart; Tay, Steven; Will, Geoffrey; Saman, Wasim; Bruno, Frank

    2016-05-01

    This paper presents the stability and corrosion testing results of a candidate high temperature phase change material (PCM) for potential use in concentrating solar power applications. The investigated PCM is a eutectic mixture of NaCl and Na2CO3 and both are low cost materials. This PCM has a melting temperature of 635 °C and a relatively high latent heat of fusion of 308.1 J/g. The testing was performed by means of an electric furnace subjected to 150 melt-freeze cycles between 600 °C and 650 °C. The results showed that this PCM candidate has no obvious decomposition up to 650 °C after 150 cycles and stainless steel 316 potentially can be used as the containment material under the minimized oxygen atmosphere.

  8. 40 CFR Appendix E to Subpart S of... - Transient Test Driving Cycle

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... E to Subpart S of Part 51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR.../Maintenance Program Requirements Pt. 51, Subpt. S, App. E Appendix E to Subpart S of Part 51—Transient Test Driving Cycle (I) Driver's trace. All excursions in the transient driving cycle shall be evaluated by...

  9. High-temperature gas stream cleanup test facility

    SciTech Connect

    Ontko, J.; Chiang, T.

    1995-12-01

    The high-temperature gas stream cleanup facility at the Morgantown Energy Technology Center will provide a versatile platform for testing novel hot gas cleanup filtration concepts. The facility will be available for joint ventures with CRADA partners.

  10. Raytheon low temperature RSP2 cryocooler airborne testing

    NASA Astrophysics Data System (ADS)

    Schaefer, B. R.; Bellis, L.; Ellis, M. J.; Conrad, T. J.

    2014-01-01

    The Raytheon Cryocooler Product Line tested the Low Temperature Stirling / Pulse Tube Hybrid 2-Stage (LTRSP2) cryocooler for an airborne application during 2012. Several tests were carried out to verify the ability of the machine to operate in an airborne environment. The vacuum level and heat rejection surface temperatures were varied to determine the performance over the excursions. Vibration testing was performed to prove that the LT-RSP2 cryocooler can operate on an airborne platform. This paper will present the results of the airborne characterization testing.

  11. Raytheon low temperature RSP2 cryocooler airborne testing

    NASA Astrophysics Data System (ADS)

    Schaefer, B. R.; Bellis, L.; Ellis, M. J.; Conrad, T. J.

    2013-09-01

    The Raytheon Cryocooler Product Line tested the Low Temperature Stirling / Pulse Tube Hybrid 2-Stage (LTRSP2) cryocooler for an airborne application during 2012. Several tests were carried out to verify the ability of the machine to operate in an airborne environment. The vacuum level and heat rejection surface temperatures were varied to determine the performance over the excursions. Vibration testing was performed to prove that the LT-RSP2 cryocooler can operate on an airborne platform. This paper will present the results of the airborne characterization testing.

  12. Notch effects on high-cycle fatigue properties of Ti 6Al 4V ELI alloy at cryogenic temperatures

    NASA Astrophysics Data System (ADS)

    Yuri, T.; Ono, Y.; Ogata, T.

    2006-01-01

    Notch effects on the high-cycle fatigue properties of the forged Ti-6Al-4V ELI alloy at cryogenic temperatures were investigated. Also, the high-cycle fatigue data were compared with the rolled Ti-5Al-2.5Sn ELI alloy. The one million cycles fatigue strength (FS) of the smooth specimen for the forged Ti-6Al-4V ELI alloy increased with a decrease of test temperature. However, the FS of each notched specimen at 4 K were lower than those at 77 K. On the other hand, the FS of the smooth and the notched specimens for the forged Ti-6Al-4V ELI alloy at 4 K were lower than those for the rolled Ti-5Al-2.5Sn ELI alloy. This is considered to be the early initiation of the fatigue crack in the forged Ti-6Al-4V ELI alloy compares with the forged Ti-5Al-2.5Sn ELI.

  13. Temperature measurement. [liquid monopropellant rocket engine performance tests

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The design, installation, checkout, calibration, and operation of a temperature measuring system to be used during tests of a liquid monopropellant rocket engine are discussed. Appendixes include: (1) temperature measurement system elemental uncertainties, and (2) tables and equations for use with thermocouples and resistance thermometers. Design guidelines are given for the critical components of each portion of the system to provide an optimum temperature measurement system which meets the performance criteria specified.

  14. 40 CFR 86.1333-90 - Transient test cycle generation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... test. The torque and rpm feedback signals may be filtered. (d) Idle Speed Enhancement Devices (e.g... feedback torque equal to zero (using, for example, clutch disengagement, speed to torque control switching... longer, the average feedback torque must be within ±10 ft-lbs of zero. To allow for transition, up to...

  15. High Temperature Evaluation of Tantalum Capacitors - Test 1

    DOE Data Explorer

    Cieslewski, Grzegorz

    2014-09-28

    Tantalum capacitors can provide much higher capacitance at high-temperatures than the ceramic capacitors. This study evaluates selected tantalum capacitors at high temperatures to determine their suitability for you in geothermal field. This data set contains results of the first test where three different types of capacitors were evaluated at 260C.

  16. Changes in basal body temperature and simple reaction times during the menstrual cycle.

    PubMed

    Simić, Nataša; Ravlić, Arijana

    2013-01-01

    Previous studies have shown cyclic changes in the activation levels and performance of different tasks throughout the menstrual cycle. The aim of this study was to examine if changes in the reaction time to both light and sound stimuli may be associated with basal body temperature changes and subjective assessments of General and High Activation during the different phases of a menstrual cycle characterized by high (preovulatory and midluteal phase) and low (menstrual and early follicular phase) levels of oestrogen and progesterone. The study included measurements of basal body temperature, simple reaction times to light and sound and self-assessment of General and High Activation during the menstrual, early follicular, late follicular and luteal phase. The sample consisted of 19 female subjects with regular menstrual cycles. The results obtained in this study indicate lower basal body temperature values during phases with low sex hormone levels, while the activation assessments suggest stable levels of both General and High Activation throughout the menstrual cycle. Similar patterns of change have been shown for reaction times in visual and auditory sensory modalities. Reaction times were shorter during phases characterized by high sex hormone levels, while phases with low hormone levels were associated with longer reaction times. From the modified text on correlations in the data analysis section, it is evident that they were calculated from averaged data from all phases of the menstrual cycle. Therefore, they do not reflect intraindividual but rather interindividual variations between the observed variables, and are not related to the hypotheses of this paper. PMID:23585200

  17. Space Station Cathode Ignition Test Status at 32,000 Cycles

    NASA Technical Reports Server (NTRS)

    Zakany, James S.; Pinero, Luis R.

    1997-01-01

    A plasma contactor system has been baselined for the International Space Station for structural potential control. An ignition procedure was developed for the plasma contactor hollow cathode assembly (HCA). To demonstrate the required 99% HCA ignition reliability over 6,000 cycles, an ignition test was conducted. An accelerated test procedure was employed to rapidly accumulate ignition cycles. The test procedure minimized the differences between accelerated and non-accelerated test results. The development HCA used in this test has achieved 32,000 ignitions to date. The HCA has been qualified for cyclic operation, which could reduce xenon consumption and extend the life of the plasma contactor system.

  18. The annual cycle of temperature in the Sahel and its climatic sensitivity

    NASA Astrophysics Data System (ADS)

    Guichard, F.; Kergoat, L.; Mougin, E.; Hourdin, F.

    2012-12-01

    In the subtropical semi-arid Sahel, a major climatic feature is the bimodal structure of the annual cycle of temperature at the surface, with two maxima surrounding the rainy season. The first one, in Spring, is particularly large in the Sahel, with monthly mean temperature reaching 35°C at 15°N. The goal of this study is to analyse (i) the thermodynamic couplings associated with this specific structure and to assess how the multi-decadal warming observed in this region has affected the structure of the annual cycle of temperature. We use several observational datasets including (i) local meteorological data (SYNOP, GISS, BEST, Hombori historical data) and the CRU and MSU gridded datasets, which all cover several decades, and (ii) high-frequency AMMA-Catch ground station data available over the last decade. The latter allow exploring couplings between temperature, water and surface energy budget. These datasets are further used to evaluate several reanalyses (ERA Interim, NCEP CFSR, MERRA and climate models (CMIP5 simulations). The observational datasets indicate that a strong increase of temperature, on the order of 1K or more, has occurred in Spring (April-May) in the Sahel over the past 60 years, with larger values at night. They further show that in Spring, the short-term inter-annual variability (less than 10 years) is the weakest, while on the other hand, the multi-decennal trend is the more pronounced. The processes associated with the increase of temperature in Spring are radically different from those accounting for temperature trends observed during the rainy season (The latter involves couplings between rainfall and temperature, with more rainfall associated with lower temperature.) Furthermore, a strong warming in Spring, as temperature is already at its annual maximum, is likely to have particularly strong societal implications. . Overall, reanalyses qualitatively reproduce the observed changes. However, the results are affected by discontinuities

  19. Initial conditioning of polymer eelectrolyte membrane fuel cell by temperature and potential cycling.

    PubMed

    Bezmalinović, Dario; Radošević, Jagoda; Barbir, Frano

    2015-01-01

    Polymer electrolyte membrane fuel cells need initial conditioning, activation or break-in the first time they are operated after being assembled. During this period performance of the fuel cell improves until it reaches its nominal performance. The exact mechanism of this initial conditioning is not completely understood, but it is assumed that during the conditioning process the polymer membrane, as well as the polymer in the catalyst layer, get humidified, and the number of active catalyst sites increases. Activation procedure proposed here consists of temperature and potential cycling. Temperature cycling is a new approach for the conditioning and the idea is to rapidly cool the running cell at some point to allow the membrane to equilibrate with condensed water which should result in higher intake of water within the membrane. The results show that proposed procedure is better or at least comparable to some conventional procedures for the initial conditioning. PMID:25830963

  20. Greenhouse warming and changes in the seasonal cycle of temperature: Model versus observations

    NASA Astrophysics Data System (ADS)

    Mann, Michael E.; Park, Jeffrey

    Thomson [1995] argues that an enhanced green-house effect may be altering the seasonal cycle in temperature. We compare trends in the amplitude and phase of the seasonal cycle in observational temperature data in the northern hemisphere with the response of two general circulation models to increased CO2 concentrations. Sizeable amplitude decreases are observed in both models and observations. Significant phase delays (ie, later seasonal transitions) are found in the simulations, opposite to the phase advances isolated in the observations. The retreat of winter sea ice in high-latitude regions appears to explain the models' response to CO2 increase. Much of the variability in the observational data is not predicted by the models.

  1. Capacity fade of Sony 18650 cells cycled at elevated temperatures. Part II. Capacity fade analysis

    NASA Astrophysics Data System (ADS)

    Ramadass, P.; Haran, Bala; White, Ralph; Popov, Branko N.

    A complete capacity fade analysis was carried out for Sony 18650 cells cycled at elevated temperatures. The major causes of capacity loss were identified and a complete capacity fade balance was carried out to account for the total capacity loss of Li-ion battery as a function of cycle number and temperature. The three most significant parameters that cause capacity loss were loss of secondary active material (LiCoO 2/carbon) and primary active material (Li +) and the rate capability losses. Intrinsic capacity measurements for both positive and negative electrode has been used to estimate the capacity loss due to secondary active material and a charge balance gives the capacity lost due to primary active material (Li +). Capacity fade has been quantified with secondary active material loss dominating the other losses.

  2. Temperature dependent mechanical property testing of nitrate thermal storage salts.

    SciTech Connect

    Iverson, Brian DeVon; Broome, Scott Thomas; Siegel, Nathan Phillip

    2010-08-01

    Three salt compositions for potential use in trough-based solar collectors were tested to determine their mechanical properties as a function of temperature. The mechanical properties determined were unconfined compressive strength, Young's modulus, Poisson's ratio, and indirect tensile strength. Seventeen uniaxial compression and indirect tension tests were completed. It was found that as test temperature increases, unconfined compressive strength and Young's modulus decreased for all salt types. Empirical relationships were developed quantifying the aforementioned behaviors. Poisson's ratio tends to increase with increasing temperature except for one salt type where there is no obvious trend. The variability in measured indirect tensile strength is large, but not atypical for this index test. The average tensile strength for all salt types tested is substantially higher than the upper range of tensile strengths for naturally occurring rock salts.

  3. 40 CFR 1039.510 - Which duty cycles do I use for transient testing?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... consists of an initial run through the transient duty cycle from a cold start, 20 minutes with no engine... established criteria as specified in 40 CFR 1065.514 to confirm that the test is valid....

  4. 40 CFR 1039.510 - Which duty cycles do I use for transient testing?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... consists of an initial run through the transient duty cycle from a cold start, 20 minutes with no engine... established criteria as specified in 40 CFR 1065.514 to confirm that the test is valid....

  5. 40 CFR 1048.510 - What transient duty cycles apply for laboratory testing?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... cycle statistics and compare with the established criteria as specified in 40 CFR 1065.514 to confirm... starting the next test. (3) You are not required to measure emissions while the engine is warming...

  6. Life cycle test results of a bipolar nickel hydrogen battery

    NASA Technical Reports Server (NTRS)

    Cataldo, R. L.

    1985-01-01

    A history of low earth orbit laboratory test data on a 6.5 Ah bipolar nickel hydrogen battery designed and built at the NASA Lewis Research Center is presented. During the past several years the storage and Thermal Branch has been deeply involved in the design, development, and optimization of nickel hydrogen devices. The bipolar concept is a means of achieving the goal of producing an acceptable battery of higher energy density, able to withstand the demands of low earth orbiter regimes.

  7. Life cycle test results of a bipolar nickel hydrogen battery

    NASA Technical Reports Server (NTRS)

    Cataldo, R. L.

    1985-01-01

    A history of low Earth orbit laboratory test data on a 6.5 Ah bipolar nickel hydrogen battery designed and built at the NASA Lewis Research Center is presented. During the past several years the Storage and Thermal Branch has been deeply involved in the design, development, and optimization of nickel hydrogen devices. The bipolar concept is a means of achieving the goal of producing an acceptable battery of higher energy density, able to withstand the demands of low Earth orbit regimes.

  8. On multi-timescale variability of temperature in China in modulated annual cycle reference frame

    NASA Astrophysics Data System (ADS)

    Qian, Cheng; Wu, Zhaohua; Fu, Congbin; Zhou, Tianjun

    2010-09-01

    The traditional anomaly (TA) reference frame and its corresponding anomaly for a given data span changes with the extension of data length. In this study, the modulated annual cycle (MAC), instead of the widely used climatological mean annual cycle, is used as an alternative reference frame for computing climate anomalies to study the multi-timescale variability of surface air temperature (SAT) in China based on homogenized daily data from 1952 to 2004. The Ensemble Empirical Mode Decomposition (EEMD) method is used to separate daily SAT into a high frequency component, a MAC component, an interannual component, and a decadal-to-trend component. The results show that the EEMD method can reflect historical events reasonably well, indicating its adaptive and temporally local characteristics. It is shown that MAC is a temporally local reference frame and will not be altered over a particular time span by an extension of data length, thereby making it easier for physical interpretation. In the MAC reference frame, the low frequency component is found more suitable for studying the interannual to longer timescale variability (ILV) than a 13-month window running mean, which does not exclude the annual cycle. It is also better than other traditional versions (annual or summer or winter mean) of ILV, which contains a portion of the annual cycle. The analysis reveals that the variability of the annual cycle could be as large as the magnitude of interannual variability. The possible physical causes of different timescale variability of SAT in China are further discussed.

  9. Influence of thermal conditioning media on Charpy specimen test temperature

    SciTech Connect

    Nanstad, R.K.; Swain, R.L.; Berggren, R.G.

    1989-01-01

    The Charpy V-notch (CVN) impact test is used extensively for determining the toughness of structural materials. Research programs in many technologies concerned with structural integrity perform such testing to obtain Charpy energy vs temperature curves. American Society for Testing and Materials Method E 23 includes rather strict requirements regarding determination and control of specimen test temperature. It specifies minimum soaking times dependent on the use of liquids or gases as the medium for thermally conditioning the specimen. The method also requires that impact of the specimen occur within 5 s removal from the conditioning medium. It does not, however, provide guidance regarding choice of conditioning media. This investigation was primarily conducted to investigate the changes in specimen temperature which occur when water is used for thermal conditioning. A standard CVN impact specimen of low-alloy steel was instrumented with surface-mounted and embedded thermocouples. Dependent on the media used, the specimen was heated or cooled to selected temperatures in the range {minus}100 to 100{degree}C using cold nitrogen gas, heated air, acetone and dry ice, methanol and dry ice, heated oil, or heated water. After temperature stabilization, the specimen was removed from the conditioning medium while the temperatures were recorded four times per second from all thermocouples using a data acquisition system and a computer. The results show that evaporative cooling causes significant changes in the specimen temperatures when water is used for conditioning. Conditioning in the other media did not result in such significant changes. The results demonstrate that, even within the guidelines of E 23, significant test temperature changes can occur which may substantially affect the Charpy impact test results if water is used for temperature conditioning. 7 refs., 11 figs.

  10. Improved cycling behavior of ZEBRA battery operated at intermediate temperature of 175 °C

    SciTech Connect

    Li, Guosheng; Lu, Xiaochuan; Kim, Jin Y.; Lemmon, John P.; Sprenkle, Vincent L.

    2014-03-01

    Operation of the sodium-nickel chloride battery at temperatures below 200°C reduces cell degradation and improves cyclability. One of the main technical issues with operating this battery at intermediate temperatures such as 175°C is the poor wettability of molten sodium on β”-alumina solid electrolyte (BASE), which causes reduced active area and limits charging. In order to overcome the poor wettability of molten sodium on BASE at 175°C, a Pt grid was applied on the anode side of the BASE using a screen printing technique. Cells with their active area increased by metallized BASEs exhibited deeper charging and stable cycling behavior.

  11. Improved cycling behavior of ZEBRA battery operated at intermediate temperature of 175 °C

    NASA Astrophysics Data System (ADS)

    Li, Guosheng; Lu, Xiaochuan; Kim, Jin Y.; Lemmon, John P.; Sprenkle, Vincent L.

    2014-03-01

    Operation of the sodium-nickel chloride battery at temperatures below 200 °C reduces cell degradation and improves cyclability. One of the main technical issues with operating this battery at intermediate temperatures such as 175 °C is the poor wettability of molten sodium on β″-alumina solid electrolyte (BASE), which causes reduced active area and limits charging. In order to overcome the poor wettability of molten sodium on BASE at 175 °C, a Pt grid was applied on the anode side of the BASE using a screen printing technique. Cells with their active area increased by metallized BASEs exhibited deeper charging and stable cycling behavior.

  12. Temperature and precipitation estimates through the last glacial cycle from Clear Lake, California, pollen data

    USGS Publications Warehouse

    Adam, D.P.; James, West G.

    1983-01-01

    Modern pollen surface samples from six lake and marsh sites in the northern California Coast Ranges establish a linear relation between elevation and the oak/(oak + pine) pollen ratio. Modern temperature and precipitation lapse rates were used to convert variations in the pollen ratio into temperature and precipitation changes. Pollen data from two cores from Clear Lake, Lake County, California, spanning the past 40,000 and 130,000 years were used to estimate temperature and precipitation changes through the last full glacial cycle. The maximum glacial cooling is estimated to be 7?? to 8??C; the last full interglacial period was about 1.5??C warmer than the Holocene, and a mid-Holocene interval was warmer than the present. The estimated precipitation changes are probably less reliable than the estimated temperature changes.

  13. Magnetocaloric cycle with six stages: Possible application of graphene at low temperature

    SciTech Connect

    Reis, M. S.

    2015-09-07

    The present work proposes a thermodynamic hexacycle based on the magnetocaloric oscillations of graphene, which has either a positive or negative adiabatic temperature change depending on the final value of the magnetic field change. For instance, for graphenes at 25 K, an applied field of 2.06 T/1.87 T promotes a temperature change of ca. −25 K/+3 K. The hexacycle is based on the Brayton cycle and instead of the usual four steps, it has six stages, taking advantage of the extra cooling provided by the inverse adiabatic temperature change. This proposal opens doors for magnetic cooling applications at low temperatures.

  14. Thermal compensator for closed-cycle helium refrigerator. [assuring constant temperature for an infrared laser diode

    NASA Technical Reports Server (NTRS)

    Jennings, D. E.; Hillman, J. J. (Inventor)

    1979-01-01

    The wave length of an infrared, semiconductor laser diode having an output frequency that is dependent on the diode temperature is maintained substantially constant by maintaining the diode temperature constant. The diode is carried by a cold tip of a closed cycle helium refrigerator. The refrigerator has a tendency to cause the temperature of the cold tip to oscillate. A heater diode and a sensor diode are placed on a thermal heat sink that is the only highly conductive thermal path between the laser diode and the cold tip. The heat sink has a small volume and low thermal capacitance so that the sensing diode is at substantially the same temperature as the heater diode and substantially no thermal lag exists between them. The sensor diode is connected in a negative feedback circuit with the heater diode so that the tendency of the laser diode to thermally oscillate is virtually eliminated.

  15. 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.

  16. 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. Previously announced in STAR as N83-25038

  17. 40 CFR 86.1363-2007 - Steady-state testing with a discrete-mode cycle.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 0.08 2 11 C 25 0.05 2 12 C 75 0.05 2 13 C 50 0.05 2 1 Speed terms are defined in 40 CFR part 1065. 2... Exhaust Test Procedures § 86.1363-2007 Steady-state testing with a discrete-mode cycle. This section... taking a sample proportional to the exhaust mass flow during each individual mode of the cycle. This...

  18. 40 CFR 86.1363-2007 - Steady-state testing with a discrete-mode cycle.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 0.08 2 11 C 25 0.05 2 12 C 75 0.05 2 13 C 50 0.05 2 1 Speed terms are defined in 40 CFR part 1065. 2... Exhaust Test Procedures § 86.1363-2007 Steady-state testing with a discrete-mode cycle. This section... taking a sample proportional to the exhaust mass flow during each individual mode of the cycle. This...

  19. Effect of light entrainment and temperature on the reproductive cycle in the male hedgehog (Erinaceus europaeus).

    PubMed

    Saboureau, M; el Omari, B

    1993-11-01

    The role of photoperiod in the entrainment and synchronization of the reproductive cycle of male hedgehogs, seasonal breeders and hibernating mammals, was investigated. Groups of adult hedgehogs were either maintained outdoors (controls, n = 6) or submitted to accelerated 6-month artificial light regimens under constant ambient temperatures (20 +/- 2 degrees C versus 5 +/- 1 degrees C) in light-proofed rooms. The daily duration of light was varied sinusoidally to produce an amplitude change from 8 h (winter solstice) to 16 h (summer solstice) during the 6-month light cycle. Animals were transferred from outdoors to a high ambient temperature (20 +/- 2 degrees C) and submitted to accelerated 6-month light regimens at two times of the year: from winter solstice (Group 1, n = 14) with increasing daylengths (from 8 to 16 h) and from summer solstice (Group 2, n = 8) with decreasing daylengths (from 16 to 8 h). The light regimens were then reversed for Groups 1 and 2. After the first 6-month cycle, the animals in Group 1 were allocated to two groups and maintained under the same initial light regimen but submitted to two ambient temperatures: Group 1 (n = 7) was maintained at 20 +/- 2 degrees C and Group 3 (n = 7) was transferred to a cold environment (5 +/- 1 degrees C). In control and experimental animals, testicular volume was estimated and blood samples were obtained twice a month to measure plasma testosterone and LH concentrations by radioimmunoassay.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8107032

  20. Solar Cycle Variability in Mean Thermospheric Composition and Temperature Induced by Atmospheric Tides

    NASA Astrophysics Data System (ADS)

    Jones, M., Jr.; Forbes, J. M.; Hagan, M. E.

    2015-12-01

    Vertically-propagating atmospheric thermal tides whose origins lie in Earth's lower atmosphere are now widely recognized as one of the dominant "meteorological" drivers of space weather. Many prior research efforts have focused on documenting and understanding the role that dissipating tides play in determining the longitudinal and seasonal variability associated with lower thermospheric winds, temperature, and constituent densities. However, considerably less attention has focused on understanding the potential solar cycle variability in the mean thermospheric state induced by the tides. In this paper we utilize the National Center for Atmospheric Research Thermosphere-Ionosphere-Electrodynamics General Circulation Model (TIE-GCM), forced with observationally-based tides at the model lower boundary from the Climatological Tidal Model of the Thermosphere (CTMT, from Oberheide et al. [2011]), to elucidate how the dissipating tides induce variations of up to 30 K in the zonal-mean thermosphere temperature between solar minimum and maximum. Numerical experiments are performed for the month of September and for solar minimum, medium, and maximum conditions in order to quantify the solar cycle variability associated with the different terms in the thermodynamic energy, major and minor neutral constituent continuity equations. Our analysis indicates that solar cycle variability in neutral temperatures results from a combination of net eddy heat transport effects and tidal modulation of net nitric oxide (NO) cooling. The chemical and dynamical pathways through which dissipating tides affect mean NO cooling differently at solar minimum and maximum are diagnosed.

  1. Design, fabrication and testing of an optical temperature sensor

    NASA Technical Reports Server (NTRS)

    Morey, W. W.; Glenn, W. H.; Decker, R. O.; Mcclurg, W. C.

    1980-01-01

    The laboratory breadboard optical temperature sensor based on the temperature dependent absorptive characteristics of a rare earth (europium) doped optical fiber. The principles of operation, materials characterization, fiber and optical component design, design and fabrication of an electrooptic interface unit, signal processing, and initial test results are discussed. Initial tests indicated that, after a brief warmup period, the output of the sensor was stable to approximately 1 C at room temperature or approximately + or - 0.3 percent of point (K). This exceeds the goal of 1 percent of point. Recommendations are presented for further performance improvement.

  2. A simple-harmonic model for depicting the annual cycle of seasonal temperatures of streams

    USGS Publications Warehouse

    Steele, Timothy Doak

    1978-01-01

    Due to economic or operational constraints, stream-temperature records cannot always be collected at all sites where information is desired or at frequencies dictated by continuous or near-continuous surveillance requirements. For streams where only periodic measurements are made during the year, and that are not appreciably affected by regulation or by thermal loading , a simple harmonic function may adequately depict the annual seasonal cycle of stream temperature at any given site. Resultant harmonic coefficients obtained from available stream-temperature records may be used in the following ways: (1) To interpolate between discrete measurements by solving the harmonic function at specified times, thereby filling in estimates of stream-temperature values; (2) to characterize areal or regional patterns of natural stream-temperature values; (2) to characterize areal or regional patterns of natural stream-temperature conditions; and (3) to detect and to assess any significant at a site brought about by streamflow regulation or basin development. Moreover, less-than-daily or sampling frequencies at a given site may give estimates of annual variation of stream temperatures that are statistically comparable to estimates obtained from a daily or continuous sampling scheme. The latter procedure may result in potential savings of resources in network operations, with negligible loss in information on annual stream-temperature variations. (Woodard -USGS)

  3. Cone Penetrometer Load Cell Temperature and Radiation Testing Results

    SciTech Connect

    Follett, Jordan R.

    2013-08-28

    This report summarizes testing activities performed at the Pacific Northwest National Laboratory to verify the cone penetrometer load cell can withstand the tank conditions present in 241-AN-101 and 241-AN-106. The tests demonstrated the load cell device will operate under the elevated temperature and radiation levels expected to be encountered during tank farm deployment of the device.

  4. Apparatus facilitates high-temperature tensile testing in vacuum

    NASA Technical Reports Server (NTRS)

    Sikora, P. F.

    1964-01-01

    An apparutus for heating refractory materials to high temperatures during tensile testing includes a water-cooled stainless steel vacuum chamber. This contains a resistance heater consisting of a slit tube of tantalum or tungsten to enclose the tensile test rod.

  5. Thermocouples For High Temperature In-Pile Testing

    SciTech Connect

    J. L. Rempe

    2005-11-01

    Many advanced nuclear reactor designs require new fuel, cladding and structural materials. Data are needed to characeterize the performance of these new materials in high temperature, oxidizing and radiation conditions. To obtain this data, robust instrumentation is needed htat can survive proposed test conditions. Traditional methods for measuring temperature in-pile degrade at temperatures above 1080 degrees C. Hence, a project was intiated to develop specialized thermocouples for high temperature in-pile applications (see Rempe and Wilkins, 2005). This paper summarizes efforts to develop, fabricate and evaluate these specialized thermocouples.

  6. The effect of ambient temperature on gross-efficiency in cycling.

    PubMed

    Hettinga, Florentina J; De Koning, Jos J; de Vrijer, Aukje; Wüst, Rob C I; Daanen, Hein A M; Foster, Carl

    2007-11-01

    Time-trial performance deteriorates in the heat. This might potentially be the result of a temperature-induced decrease in gross-efficiency (GE). The effect of high ambient temperature on GE during cycling will be studied, with the intent of determining if a heat-induced change in GE could account for the performance decrements in time trial exercise found in literature. Ten well-trained male cyclists performed 20-min cycle ergometer exercise at 60% PVO2max (power output at which VO2max was attained) in a thermo-neutral climate (N) of 15.6+/-0.3 degrees C, 20.0+/-10.3% RH and a hot climate (H) of 35.5+/-0.5 degrees C, 15.5+/-3.2% RH. GE was calculated based on VO2 and RER. Skin temperature (Tsk), rectal temperature (Tre) and muscle temperature (Tm) (only in H) were measured. GE was 0.9% lower in H compared to N (19.6+/-1.1% vs. 20.5+/-1.4%) (P<0.05). Tsk (33.4+/-0.6 degrees C vs. 27.7+/-0.7 degrees C) and Tre (37.4+/-0.6 degrees C vs. 37.0+/-0.6 degrees C) were significantly higher in H. Tm was 38.7+/-1.1 degrees C in H. GE was lower in heat. Tm was not high enough to make mitochondrial leakage a likely explanation for the observed reduced GE. Neither was the increased Tre. Increased skin blood flow might have had a stealing effect on muscular blood flow, and thus impacted GE. Cycling model simulations showed, that the decrease in GE could account for half of the performance decrement. GE decreased in heat to a degree that could explain at least part of the well-established performance decrements in the heat. PMID:17661069

  7. 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

  8. Test temperature compensated gas meters with sonic nozzles

    SciTech Connect

    Giglio, P.F.

    1983-01-01

    Explains how a sonic nozzle test facility gives accurate, repeatable results in all temperatures. Niagara Mohawk Power Corp., in late 1963, made a decision to introduce the temperature compensated gas meter into their system to facilitate outdoor meter locations. The test facility was constructed utilizing a water and ethylene glycol bath to condition the gas meter and test medium (air) to the nominal temperature requirements. Sonic nozzles produced extremely repeatable test results from the very beginning. Meter testing time could be considerably reduced due to the inherent repeatability of the sonic nozzles and the simplicity of accurately measuring time, temperature and the relative humidity of the test medium. The sonic nozzles were connected to the outlet of the bell prover with their inlet facing the bell prover side of the connection. A vacuum source was then connected to the outlet side of the sonic nozzle to provide the differential pressure necessary to achieve sonic flow. Based on the test results it was decided to utilize 3-psi vacuum for the calibration of the sonic nozzles.

  9. Temperature controlled material irradiation in the advanced test reactor

    NASA Astrophysics Data System (ADS)

    Ingram, F. W.; Palmer, A. J.; Stites, D. J.

    1998-10-01

    The United States Department of Energy (US DOE) has initiated the development of an Irradiation Test Vehicle (ITV) for fusion materials irradiation at the Advanced Test Reactor (ATR) in Idaho Falls, Idaho, USA. The ITV is capable of providing neutron spectral tailoring and individual temperature control for up to 15 experiment capsules simultaneously. The test vehicle consists of three In-Pile Tubes (IPTs) running the length of the reactor vessel. These IPTs are kept dry and test trains with integral instrumentation are inserted and removed through a transfer shield plate above the reactor vessel head. The test vehicle is designed to irradiate specimens as large as 2.2 cm in diameter, at temperatures of 250-800°C, achieving neutron damage rates as high as 10 displacements per atom per year. The high fast to thermal neutron flux ratio required for fusion materials testing is accomplished by using an aluminum filler to displace as much water as possible from the flux trap and surrounding the filler piece with a ring of replaceable neutron absorbing material. The gas blend temperature control system remains in place from test to test, thus hardware costs for new tests are limited to the experiment capsule train and integral instrumentation.

  10. Influence of temperature on the life-cycle of Globodera spp.

    PubMed

    Blok, V; Kaczmarek, A; Palomares-Rius, J E

    2011-01-01

    The potato cyst nematodes (PCN) G. rostochiensis (Woll.) and G. pallida (Stone) are the most economically important pests of potato (Solanum tuberosum L.) in the UK and are widespread in ware potato growing regions in Europe. The new EU directive 2007/33/EC which came into effect July 1, 2010 aims to control their spread and limit further increases in populations. We are investigating the role of temperature in the life cycle of PCN to assess how this effects population multiplication in relation to managing PCN. Hatching and nematode development are stages in the life cycle that are affected by temperature and thus are important life stages that can be examined to determine the impact of temperature on the length of time required for one generation to be completed and the potential for final populations to increase on different potato genetic backgrounds. In some conditions a partial or complete second generation has also been observed within the growing season. Females have been observed on the surface of tubers and "pecking" skin damage can occur which may be a result of a second generation. We are investigating the influence of temperature on the potential for a second generation or the induction of diapause. PMID:22696942

  11. High Temperature Fusion Reactor Cooling Using Brayton Cycle Based Partial Energy Conversion

    NASA Technical Reports Server (NTRS)

    Juhasz, Albert J.; Sawicki, Jerzy T.

    2003-01-01

    For some future space power systems using high temperature nuclear heat sources most of the output energy will be used in other than electrical form, and only a fraction of the total thermal energy generated will need to be converted to electrical work. The paper describes the conceptual design of such a partial energy conversion system, consisting of a high temperature fusion reactor operating in series with a high temperature radiator and in parallel with dual closed cycle gas turbine (CCGT) power systems, also referred to as closed Brayton cycle (CBC) systems, which are supplied with a fraction of the reactor thermal energy for conversion to electric power. Most of the fusion reactor's output is in the form of charged plasma which is expanded through a magnetic nozzle of the interplanetary propulsion system. Reactor heat energy is ducted to the high temperature series radiator utilizing the electric power generated to drive a helium gas circulation fan. In addition to discussing the thermodynamic aspects of the system design the authors include a brief overview of the gas turbine and fan rotor-dynamics and proposed bearing support technology along with performance characteristics of the three phase AC electric power generator and fan drive motor.

  12. Cycle life test. Evaluation program for secondary spacecraft cells. [performance tests on silver zinc batteries, silver cadmium batteries, and nickel cadmium batteries

    NASA Technical Reports Server (NTRS)

    Harkness, J. D.

    1976-01-01

    Considerable research is being done to find more efficient and reliable means of starting electrical energy for orbiting satellites. Rechargeable cells offer one such means. A test program is described which has been established in order to further the evaluation of certain types of cells and to obtain performance and failure data as an aid to their continued improvement. The purpose of the program is to determine the cycling performance capabilities of packs of cells under different load and temperature conditions. The various kinds of cells tested were nickel-cadmium, silver-cadmium, and silver-zinc sealed cells. A summary of the results of the life cycling program is given in this report.

  13. Combined cycle electric power plant with feedforward afterburner temperature setpoint control

    SciTech Connect

    Uram, R.

    1982-06-08

    A combined cycle electric power plant includes gas and steam turbines and a steam generator for recovering the heat in the exhaust gases exited from the gas turbine and for using the recovered heat to produce and supply steam to the steam turbine. The steam generator includes a superheater tube through which a fluid, e.g. water, is directed to be additionally heated into superheated steam by the exhaust gas turbine gases. An afterburner further heats the exhaust gas turbine gases passed to the superheater tube. The temperature of the gas turbine exhaust gases is sensed for varying the fuel flow to the afterburner by a fuel valve, whereby the temperatures of the gas turbine exhaust gases and therefore of the superheated steam, are controlled. The afterburner fuel flow is controlled through a feedforward setpoint signal derived as a predetermined function of sensed gas turbine exhaust temperature.

  14. Magnetization, anomalous Barkhausen effect, and core loss of Supermendur under high temperature cycling.

    NASA Technical Reports Server (NTRS)

    Niedra, J. M.; Schwarze, G. E.

    1971-01-01

    The magnetization and core loss of Supermendur were measured up to 900 C under conditions of slow temperature cycling in vacuum. As a consequence of this heating, the coercivity at 25 C increased from 21 A/m to about 110 A/m. This increase is less than previously reported. A prominent anomalous Barkhausen effect, pinched-in hysteresis loops, and a magnetic viscosity field in excess of 20 A/m were observed in the range of 600 to 700 C. At 850 C, Supermendur had a coercivity of 23 A/m, a saturation induction exceeding 1.5 T, a core loss of 26 W/kg at 400 Hz, and a maximum induction of 1.5 T. Supermendur may be useful for high temperature soft magnetic material applications where some history dependence of properties and instability of minor loops at lower temperatures is acceptable.

  15. High temperature low-cycle fatigue mechanisms in single crystals of nickel-based superalloy Mar-M 200

    NASA Technical Reports Server (NTRS)

    Milligan, W. W.; Jayaraman, N.

    1984-01-01

    Twenty three high temperature low-cycle fatigue tests were conducted on single crystals of the nickel-based superalloy Mar-M 200. Tests were conducted at 760 and 870 C. SEM fractography and transmission electron microscopy were used to determine mechanisms responsible for the observed orientation dependent fatigue behavior. It has been concluded that the plastic characteristics of the alloy lead to orientation-dependent strain hardening and fatigue lives at 760 C. At 870 C, the elastic characteristics of the alloy dominated the behavior, even though the plastic strain ranges were about the same as they were at 760 C. This led to orientation-dependent fatigue lives, but the trends were not the same as they were at 760 C.

  16. Non contact mechanical testing at high temperature using electromagnetic forces

    NASA Astrophysics Data System (ADS)

    Gangireddy, Sindhura

    Ultra high temperature ceramics (UHTCs) recently captured interest as potential materials for reusable thermal protection systems and other components in future generation supersonic and hypersonic vehicles where temperatures can reach > 2000 °C. A novel method for mechanical testing of UHTCs at such ultra high temperatures is developed utilizing electromagnetic force. Resistively heated and self-supported specimens in thin ribbon geometry under application of a transverse magnetic field undergo flexural stress from the electromagnetic Lorentz forces, which act as a distributed mechanical load and deform the specimen. This non-contact technique, termed Electro-Magnetic Mechanical Apparatus (EMMA), allows performing rapid tests in a low cost table-top apparatus at temperatures, as high as 2200 °C, otherwise impossible to achieve. The flexibility of this method offers ample opportunity to explore a wide range of mechanical properties. For example utilizing a DC current for resistive heating with a DC magnetic field creates constant loads for Creep testing; replacing with a AC current generates cyclic loads for Fatigue testing; larger magnetic fields can be used for Fast -- Fracture experiments; and impulse excitation of the magnetic field vibrates the specimens and enables the determination of the material's Elastic and Loss Modulus. Zirconium Diboride and Silicon Carbide (ZrB2-SiC) is a prominent member of UHTCs. The creep properties of this composite are explored using this technique in the temperature range 1600 -- 2200 °C under stress ranging from 20 -- 50 MPa in ambient air as well as non-reactive Nitrogen atmosphere. The kinetic parameters of creep, activation energy and stress exponent are established in the testing range. The creep response from the two environments is compared to understand the effect of the concomitant oxidation during high temperature testing in air. Comparison of creep data from conventional 3-pt, 4-pt flexure tests corroborate the

  17. Development of a Supercritical Carbon Dioxide Brayton Cycle: Improving VHTR Efficiency and Testing Material Compatibility - Final Report

    SciTech Connect

    Chang H. Oh

    2006-06-01

    Generation IV reactors will need to be intrinsically safe, having a proliferation-resistant fuel cycle and several advantages relative to existing light water reactor (LWR). They, however, must still overcome certain technical issues and the cost barrier before it can be built in the U.S. The establishment of a nuclear power cost goal of 3.3 cents/kWh is desirable in order to compete with fossil combined-cycle, gas turbine power generation. This goal requires approximately a 30 percent reduction in power cost for stateof-the-art nuclear plants. It has been demonstrated that this large cost differential can be overcome only by technology improvements that lead to a combination of better efficiency and more compatible reactor materials. The objectives of this research are (1) to develop a supercritical carbon dioxide Brayton cycle in the secondary power conversion side that can be applied to the Very-High-Temperature Gas-Cooled Reactor (VHTR), (2) to improve the plant net efficiency by using the carbon dioxide Brayton cycle, and (3) to test material compatibility at high temperatures and pressures. The reduced volumetric flow rate of carbon dioxide due to higher density compared to helium will reduce compression work, which eventually increase plant net efficiency.

  18. The temperature of quiescent streamers during solar cycles 23 and 24

    SciTech Connect

    Landi, E.; Testa, P.

    2014-05-20

    Recent in-situ determinations of the temporal evolution of the charge state distribution in the fast and slow solar wind have shown a general decrease in the degree of ionization of all the elements in the solar wind along solar cycles 23 and 24. Such a decrease has been interpreted as a cooling of the solar corona which occurred during the decline and minimum phase of solar cycle 23 from 2000 to 2010. In the present work, we investigate whether spectroscopic determinations of the temperature of the quiescent streamers show signatures of coronal plasma cooling during cycles 23 and 24. We measure the coronal electron density and thermal structure at the base of 60 quiescent streamers observed from 1996 to 2013 by SOHO/SUMER and Hinode/EIS and find that both quantities do now show any significant dependence on the solar cycle. We argue that if the slow solar wind is accelerated from the solar photosphere or chromosphere, the measured decrease in the in-situ wind charge state distribution might be due to an increased efficiency in the wind acceleration mechanism at low altitudes. If the slow wind originates from the corona, a combination of density and wind acceleration changes may be responsible for the in-situ results.

  19. The Temperature of Quiescent Streamers during Solar Cycles 23 and 24

    NASA Astrophysics Data System (ADS)

    Landi, E.; Testa, P.

    2014-05-01

    Recent in-situ determinations of the temporal evolution of the charge state distribution in the fast and slow solar wind have shown a general decrease in the degree of ionization of all the elements in the solar wind along solar cycles 23 and 24. Such a decrease has been interpreted as a cooling of the solar corona which occurred during the decline and minimum phase of solar cycle 23 from 2000 to 2010. In the present work, we investigate whether spectroscopic determinations of the temperature of the quiescent streamers show signatures of coronal plasma cooling during cycles 23 and 24. We measure the coronal electron density and thermal structure at the base of 60 quiescent streamers observed from 1996 to 2013 by SOHO/SUMER and Hinode/EIS and find that both quantities do now show any significant dependence on the solar cycle. We argue that if the slow solar wind is accelerated from the solar photosphere or chromosphere, the measured decrease in the in-situ wind charge state distribution might be due to an increased efficiency in the wind acceleration mechanism at low altitudes. If the slow wind originates from the corona, a combination of density and wind acceleration changes may be responsible for the in-situ results.

  20. Changes in scores on the Mental Rotations Test during the menstrual cycle.

    PubMed

    Moody, M S

    1997-06-01

    The purpose of the study was to examine changes in performance on Vandenberg's Mental Rotations Test during the menstrual cycles of college women. Participants were 12 male and 34 female students recruited from undergraduate educational psychology and nursing classes at a large southeastern university. Each woman was tested once during the menstrual phase and once during the luteal phase of her menstrual cycle. Phases in which the testings occurred were counterbalanced. Men were also tested twice. For all participants, the two testing sessions were held exactly 14 days apart. Women who were contraceptive pill users did not perform significantly differently during either phase from women who were nonusers, and there was no interaction for pill use by phase. Therefore, users and nonusers were combined for a paired-sample t test which indicated that women scored significantly higher during the menstrual phase (Days 2-7) than during the luteal phase (Days 16-22 for 31 women and Days 24-26 for three women with longer cycles). The 12 men scored significantly higher than the 34 women during the initial testing; but not significantly higher than the 17 women who were in the menstrual phase during the first testing. Therefore, that the effect of the phase of menstrual cycle influences the sex difference in performance on the Mental Rotations Test was supported. PMID:9172209

  1. Modeling of Temperature Conditions Between Temperature Artifact and Black Test Corner

    NASA Astrophysics Data System (ADS)

    Beges, G.

    2011-12-01

    The case study in this article is temperature condition modeling between a temperature artifact and a black test corner measuring instrument. The black test corner is an instrument which consists of two wooden walls and a floor, with build-in thermocouples fixed on the back side of the copper disks. The front of the disk is flush with the surface of the board. The black test corner is used for measuring how the temperature of a household appliance is influencing the surroundings in the real environment, e.g., in the kitchen, the living room, etc. The temperature artifact as presented in this article is a specially developed heating plate which is very stable and can be set to different temperatures. Technical standards for conformity assessment usually describe only what should be measured, in some cases also how accurate the measurement should be, but not what kind of measuring instrument should be used. Therefore, it sometimes happens that measurements are performed with improper equipment or in an improper way. For the same level of appliance conformance testing, laboratories shall use the same testing procedures and comparable measuring instruments. This article deals with the analysis of influencing parameters when measuring the temperature rise using the black test corner. Modeling of temperature conditions between a temperature artifact and a black test corner, using commercial modeling software, was performed to find out whether this modeling can be used for detailed evaluation of all possible influencing parameters of the mentioned testing procedure. A scheme and a list of influencing parameters that has to be modeled in the following research is prepared to arrange an optimal experiment.

  2. Effect of Gas/Steam Turbine Inlet Temperatures on Combined Cycle Having Air Transpiration Cooled Gas Turbine

    NASA Astrophysics Data System (ADS)

    Kumar, S.; Singh, O.

    2012-10-01

    Worldwide efforts are being made for further improving the gas/steam combined cycle performance by having better blade cooling technology in topping cycle and enhanced heat recovery in bottoming cycle. The scope of improvement is possible through turbines having higher turbine inlet temperatures (TITs) of both gas turbine and steam turbine. Literature review shows that a combined cycle with transpiration cooled gas turbine has not been analyzed with varying gas/steam TITs. In view of above the present study has been undertaken for thermodynamic study of gas/steam combined cycle with respect to variation in TIT in both topping and bottoming cycles, for air transpiration cooled gas turbine. The performance of combined cycle with dual pressure heat recovery steam generator has been evaluated for different cycle pressure ratios (CPRs) varying from 11 to 23 and the selection diagrams presented for TIT varying from 1,600 to 1,900 K. Both the cycle efficiency and specific work increase with TIT for each pressure ratio. For each TIT there exists an optimum pressure ratio for cycle efficiency and specific work. For the CPR of 23 the best cycle performance is seen at a TIT of 1,900 K for maximum steam temperature of 570 °C, which gives the cycle efficiency of 60.9 % with net specific work of 909 kJ/kg.

  3. Friction Tests in Magnesium Tube Hydroforming at Elevated Temperatures

    SciTech Connect

    Hwang, Yeong-Maw; Wang, Kuo-Hsing; Kuo, Tsung-Yu

    2011-05-04

    In metal forming, lubricants have a variety of functions. The top priority is usually reduction of friction in order to increase the formability of the materials and reduce tool wear. Because magnesium alloys have very poor formability at room temperature, it is essential to manufacture a part from Magnesium alloys at elevated temperatures. The aim of this paper is to present a friction test method to evaluate the performance of different kinds of lubricants and determine their coefficients of friction at elevated temperatures in tube hydroforming of magnesium alloys. A self-designed experimental apparatus is used to carry out the experiments of friction tests. The coefficient of friction between the tube and die at guiding zone is determined. The effects of the internal pressure, the axial feeding velocity and temperatures on the friction forces and coefficients of friction for different lubricants are discussed.

  4. Control of continuous irradiation injury on potatoes with daily temperature cycling

    NASA Technical Reports Server (NTRS)

    Tibbitts, T. W.; Bennett, S. M.; Cao, W.

    1990-01-01

    Two controlled-environment experiments were conducted to determine the effects of temperature fluctuations under continuous irradiation on growth and tuberization of two potato (Solanum tuberosum L.) cultivars, Kennebec and Superior. These cultivars had exhibited chlorotic and stunted growth under continuous irradiation and constant temperatures. The plants were grown for 4 weeks in the first experiment and for 6 weeks in the second experiment. Each experiment was conducted under continuous irradiation of 400 micromoles per square meter per second of photosynthetic photon flux and included two temperature treatments: constant 18 degrees C and fluctuating 22 degrees C/14 degrees C on a 12-hour cycle. A common vapor pressure deficit of 0.62 kilopascal was maintained at all temperatures. Plants under constant 18 degrees C were stunted and had chlorotic and abscised leaves and essentially no tuber formation. Plants grown under the fluctuating temperature treatment developed normally, were developing tubers, and had a fivefold or greater total dry weight as compared with those under the constant temperature. These results suggest that a thermoperiod can allow normal plant growth and tuberization in potato cultivars that are unable to develop effectively under continuous irradiation.

  5. Improved Nominal Operating Cell Temperature (NOCT) test procedure

    NASA Technical Reports Server (NTRS)

    Wen, L.; Berns, D.

    1984-01-01

    A procedure is developed to improve testing of Nominal Operating Cell Temperature (NOCT) as it applies to solar energy conversion modules. NOCT is a direct reflection of module thermal design and is closely related to the representative ambient temperature. It is also a key to array energy production and estimates of module lifetimes. Present NOCT test and evaluation procedures are inconsistent, producing significant scatter. Test refinements would specify a clear sky, the addition of 10% to the insolation level for ground reflection, the addition of a ground emission factor of 0.8 (at 30C ground temperature), an effective wind direction of 135 degrees from the North, and a module tilt of 30 degrees from the horizon.

  6. Test facility for the solar-powered/fuel-assisted hybrid Rankine cycle ('SSPRE'). A Phase III report

    SciTech Connect

    Subbiah, S.; Lior, N.

    1983-05-01

    This report describes the design and construction of an experimental test facility to test a novel hybrid steam Rankine cycle. Steam from the municipal pipes is conditioned to simulate that generated by a low temperature source, such as solar energy at about 100/sup 0/C. It is then superheated up to about 600/sup 0/C in a gas-fired superheater, and drives a novel counter-rotating radial turbine. Some of the heat is regenerated and the steam is then condensed. The design of the test facility was based on the ASME steam turbine test codes, and on a thorough error analysis which helped identify unacceptable errors. The test-bed was built in the power laboratory of the University of Pennsylvania. The lay-out of the components was based on a ''bread-board'' approach, to allow easy testing and replacement of components, and yet keep the pressure drop in the steam pipes to an acceptably low level. The facility is carefully instrumented to measure all variables of interest: 19 temperature sensors, 23 pressure sensors, 9 differential pressure sensors, 2 level gauges, 7 flowmeters, 1 torque and 1 RPM measuring sensor, and a dynamometer, are used. A computerized data acquisition system is used to scan and measure 32 of these variables, and programs were developed to have it perform real-time analysis and output the results. Turbine supervisory monitoring instrumentation was installed for speed, vibration, bearing oil temperature and pressure, and location of the rotors. The control system was designed to automatically shut the steam supply and the superheater, and brake the turbine, whenever any of turbine's supervisory monitors senses an unacceptable excursion, or by manual input from the operator. A detailed program for testing the turbine and cycle performance over a wide range of parameters is presented.

  7. Recovery of Information from the Fast Flux Test Facility for the Advanced Fuel Cycle Initiative

    SciTech Connect

    Nielsen, Deborah L.; Makenas, Bruce J.; Wootan, David W.; Butner, R. Scott; Omberg, Ronald P.

    2009-09-30

    The Fast Flux Test Facility is the most recent Liquid Metal Reactor to operate in the United States. Information from the design, construction, and operation of this reactor was at risk as the facilities associated with the reactor are being shut down. The Advanced Fuel Cycle Initiative is a program managed by the Office of Nuclear Energy of the U.S. Department of Energy with a mission to develop new fuel cycle technologies to support both current and advanced reactors. Securing and preserving the knowledge gained from operation and testing in the Fast Flux Test Facility is an important part of the Knowledge Preservation activity in this program.

  8. Preliminary tests of an advanced high-temperature combustion system

    NASA Technical Reports Server (NTRS)

    Wear, J. D.; Trout, A. M.; Smith, J. M.; Jacobs, R. E.

    1983-01-01

    A combustion system has been developed to operate efficiently and with good durability at inlet pressures to 4.05 MPa (40 atm), inlet air temperatures to 900 K, and exhaust gas temperatures to 2480 K. A preliminary investigation of this system was conducted at inlet pressures to 0.94 MPa (9 atm), a nominal inlet air temperature of 560 K, and exhaust gas temperatures to 2135 K. A maximum combustion efficiency of 98.5 percent was attained at a fuel-air ratio of 0.033; the combustion efficiency decreased to about 90 percent as the fuel-air ratio was increased to 0.058. An average liner metal temperature of 915 K, 355 kelvins greater than the nominal inlet air temperature, was reached with an average exhaust gas temperature of 2090 K. The maximum local metal temperature at this condition was about 565 kelvins above the nominal inlet air temperature and decreased to 505 kelvins above with increasing combustor pressure. Tests to determine the isothermal total pressure loss of the combustor showed a liner loss of 1.1 percent and a system loss of 6.5 percent.

  9. Brayton-Cycle Heat Recovery System Characterization Program. Glass-furnace facility test plan

    SciTech Connect

    Not Available

    1980-08-29

    The test plan for development of a system to recover waste heat and produce electricity and preheated combustion air from the exhaust gases of an industrial glass furnace is described. The approach is to use a subatmospheric turbocompressor in a Brayton-cycle system. The operational furnace test requirements, the operational furnace environment, and the facility design approach are discussed. (MCW)

  10. 40 CFR Appendix II to Part 1054 - Duty Cycles for Laboratory Testing

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... § 1054.505. b Test engines at 100 percent torque by setting operator demand to maximum. Control torque during idle at its warm idle speed as described in 40 CFR 1065.510. (b) Test nonhandheld engines with one... with the following steady-state duty cycle: G3 mode No. Engine speed a Torque(percent) b...

  11. 40 CFR Appendix II to Part 1054 - Duty Cycles for Laboratory Testing

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... § 1054.505. b Test engines at 100 percent torque by setting operator demand to maximum. Control torque during idle at its warm idle speed as described in 40 CFR 1065.510. (b) Test nonhandheld engines with one... with the following steady-state duty cycle: G3 mode No. Engine speed a Torque(percent) b...

  12. 40 CFR Appendix II to Part 1054 - Duty Cycles for Laboratory Testing

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... § 1054.505. b Test engines at 100 percent torque by setting operator demand to maximum. Control torque during idle at its warm idle speed as described in 40 CFR 1065.510. (b) Test nonhandheld engines with one... with the following steady-state duty cycle: G3 mode No. Engine speed a Torque(percent) b...

  13. The sleep-wake cycle and motor activity, but not temperature, are disrupted over the light-dark cycle in mice genetically depleted of serotonin

    PubMed Central

    Solarewicz, Julia Z.; Angoa-Perez, Mariana; Kuhn, Donald M.; Mateika, Jason H.

    2016-01-01

    We examined the role that serotonin has in the modulation of sleep and wakefulness across a 12-h:12-h light-dark cycle and determined whether temperature and motor activity are directly responsible for potential disruptions to arousal state. Telemetry transmitters were implanted in 24 wild-type mice (Tph2+/+) and 24 mice with a null mutation for tryptophan hydroxylase 2 (Tph2−/−). After surgery, electroencephalography, core body temperature, and motor activity were recorded for 24 h. Temperature for a given arousal state (quiet and active wake, non-rapid eye movement, and paradoxical sleep) was similar in the Tph2+/+ and Tph2−/− mice across the light-dark cycle. The percentage of time spent in active wakefulness, along with motor activity, was decreased in the Tph2+/+ compared with the Tph2−/− mice at the start and end of the dark cycle. This difference persisted into the light cycle. In contrast, the time spent in a given arousal state was similar at the remaining time points. Despite this similarity, periods of non-rapid-eye-movement sleep and wakefulness were less consolidated in the Tph2+/+ compared with the Tph2−/− mice throughout the light-dark cycle. We conclude that the depletion of serotonin does not disrupt the diurnal variation in the sleep-wake cycle, motor activity, and temperature. However, serotonin may suppress photic and nonphotic inputs that manifest at light-dark transitions and serve to shorten the ultraradian duration of wakefulness and non-rapid-eye-movement sleep. Finally, alterations in the sleep-wake cycle following depletion of serotonin are unrelated to disruptions in the modulation of temperature. PMID:25394829

  14. The sleep-wake cycle and motor activity, but not temperature, are disrupted over the light-dark cycle in mice genetically depleted of serotonin.

    PubMed

    Solarewicz, Julia Z; Angoa-Perez, Mariana; Kuhn, Donald M; Mateika, Jason H

    2015-01-01

    We examined the role that serotonin has in the modulation of sleep and wakefulness across a 12-h:12-h light-dark cycle and determined whether temperature and motor activity are directly responsible for potential disruptions to arousal state. Telemetry transmitters were implanted in 24 wild-type mice (Tph2(+/+)) and 24 mice with a null mutation for tryptophan hydroxylase 2 (Tph2(-/-)). After surgery, electroencephalography, core body temperature, and motor activity were recorded for 24 h. Temperature for a given arousal state (quiet and active wake, non-rapid eye movement, and paradoxical sleep) was similar in the Tph2(+/+) and Tph2(-/-) mice across the light-dark cycle. The percentage of time spent in active wakefulness, along with motor activity, was decreased in the Tph2(+/+) compared with the Tph2(-/-) mice at the start and end of the dark cycle. This difference persisted into the light cycle. In contrast, the time spent in a given arousal state was similar at the remaining time points. Despite this similarity, periods of non-rapid-eye-movement sleep and wakefulness were less consolidated in the Tph2(+/+) compared with the Tph2(-/-) mice throughout the light-dark cycle. We conclude that the depletion of serotonin does not disrupt the diurnal variation in the sleep-wake cycle, motor activity, and temperature. However, serotonin may suppress photic and nonphotic inputs that manifest at light-dark transitions and serve to shorten the ultraradian duration of wakefulness and non-rapid-eye-movement sleep. Finally, alterations in the sleep-wake cycle following depletion of serotonin are unrelated to disruptions in the modulation of temperature. PMID:25394829

  15. Description of a system for interlocking elevated temperature mechanical tests

    SciTech Connect

    Schmale, D.T.; Poulter, G.A.

    1995-07-01

    Long term mechanical creep and fatigue testing at elevated temperatures requires reliable systems with safeguards to prevent destruction of equipment, loss of data and negative environmental impacts. Toward this goal, a computer controlled system has been developed and built for interlocking tests run on elevated temperature mechanical test facilities. Sensors for water flow, water pressure, water leakage, temperature, power and hydraulic status are monitored to control specimen heating equipment through solid state relays and water solenoid valves. The system is designed to work with the default interlocks present in the RF generators and mechanical tests systems. Digital hardware consists of two National Instruments 1/0 boards mounted in a Macintosh IIci computer. Software is written in National Instruments LabVIEW. Systems interlocked include two MTS closed loop servo controlled hydraulic test frames, one with an RF generator and one with both an RF generator and a quartz lamp furnace. Control for individual test systems is modularized making the addition of more systems simple. If any of the supporting utilities fail during tests, heating systems, chill water and hydraulics are powered down, minimizing specimen damage and eliminating equipment damage. The interlock control is powered by an uninterruptible power supply. Upon failure the cause is documented in an ASCII file.

  16. A note on the annual cycles of surface heat balance and temperature over a continent. [North America

    NASA Technical Reports Server (NTRS)

    Spar, J.; Crane, G.

    1974-01-01

    A surface heating function, defined as the ratio of the time derivative of the mean annual temperature curve to the surface heat balance, is computed from the annual temperature range and heat balance data for the North American continent. An annual cycle of the surface heat balance is then reconstructed from the surface heating function and the annual temperature curve, and an annual cycle of evaporative plus turbulent heat loss is recomputed from the annual cycles of radiation balance and surface heat balance for the continent. The implications of these results for long range weather forecasting are discussed.

  17. Temperature cycling periods affect growth and tuberization in potatoes under continuous irradiation

    NASA Technical Reports Server (NTRS)

    Cao, W.; Tibbitts, T. W.

    1992-01-01

    Plants of the potato (Solanum tuberosum L.) cultivars Denali, Norland, Haig and Kennebec were grown for 42 days under three temperature cycling periods (thermoperiods) with continuous irradiation in two repeated experiments to help determine if temperature cycling might be varied to optimize tuber development of potatoes in controlled environments. Thermoperiods of 6/6 hours, 12/12 hours and 24/24 hours were established with the same temperature change of 22/14C and same controlled vapor pressure deficit of 0.60 kPa. The thermoperiod of 24/24 hours significantly promoted tuber initiation but slowed tuber enlargement in all four cultivars, compared to the thermoperiods of 6/6 hours and 12/12 hours. Denali' produced the highest tuber and total dry weights under the 6/6 hours thermoperiod. Kennebec' produced the highest tuber dry weight under the 12/12 hours thermoperiod. Thermoperiods had no significant effect on shoot and root dry weights of any cultivars. The major effect of thermoperiods was on initiation and enlargement of tubers.

  18. Structural relaxations in H2-substituted myoglobin observed by temperature-cycling hole burning

    NASA Astrophysics Data System (ADS)

    Shibata, Yutaka; Kurita, Atusi; Kushida, Takashi

    1996-03-01

    A spectral hole-burning experiment has been carried out on H2-protoporphyrin-substituted myoglobin by cycling temperature from 4 K up to 70 K. When the excursion temperature Tc is below 30 K, the spectral diffusion kernel (SDK) has been found to show a Lorentzian shape. A steep increase in the hole width has been observed around 20 K, which is attributed to a narrow distribution of the barrier height of two-level systems (TLS's) in myoglobin. When Tc is raised to ˜50 K, on the other hand, the major broadening has occurred in the tail of the hole, and the SDK has deviated significantly from a Lorentzian line shape. The hole profiles after the temperature cycling have been analyzed by the stochastic model which assumes that the spectral diffusion is induced by random flips of TLS's. Both the non-Lorentzian SDK for Tc around 50 K and the Lorentzian SDK around 20 K have been found to be reproduced well by this model, if the finite size of the protein is taken into account. The details of the fitting procedure and the determined values of the number and the coupling constant of TLS's in myoglobin are presented.

  19. North atlantic deepwater temperature change during late pliocene and late quaternary climatic cycles

    USGS Publications Warehouse

    Dwyer, G.S.; Cronin, T. M.; Baker, P.A.; Raymo, M.E.; Buzas, Jeffrey S.; Correge, T.

    1995-01-01

    Variations in the ratio of magnesium to calcium (Mg/Ca) in fossil ostracodes from Deep Sea Drilling Project Site 607 in the deep North Atlantic show that the change in bottom water temperature during late Pliocene 41,000-year obliquity cycles averaged 1.5??C between 3.2 and 2.8 million years ago (Ma) and increased to 2.3??C between 2.8 and 2.3 Ma, coincidentally with the intensification of Northern Hemisphere glaciation. During the last two 100,000-year glacial-to-interglacial climatic cycles of the Quaternary, bottom water temperatures changed by 4.5??C. These results show that glacial deepwater cooling has intensified since 3.2 Ma, most likely as the result of progressively diminished deep-water production in the North Atlantic and of the greater influence of Antarctic bottom water in the North Atlantic during glacial periods. The ostracode Mg/Ca data also allow the direct determination of the temperature component of the benthic foraminiferal oxygen isotope record from Site 607, as well as derivation of a hypothetical sea-level curve for the late Pliocene and late Quaternary. The effects of dissolution on the Mg/Ca ratios of ostracode shells appear to have been minimal.

  20. Low cycle fatigue of FeAl(42 at. % Al) at room temperature

    SciTech Connect

    Hanes, D.B.; Gibala, R.

    1997-12-31

    The monotonic mechanical behavior in tension and compression of FeAl has been well documented. However, very little work has been done on the cyclic deformation behavior of this material. In this work, the behavior of FeAl (42 at. % Al) under low cycle fatigue was studied, including the effects of test environments and surface coatings. It was found that the fatigue life of this alloy is limited by environmental embrittlement. This embrittlement process can be equally well prevented by deformation in an oxygen environment or by coating the alloy with a protective film. The type of film applied appears to have little effect. Similar results were seen in monotonic testing.

  1. Heat exchanger temperature response for duty-cycle transients in the NGNP/HTE.

    SciTech Connect

    Vilim, R. B.; Nuclear Engineering Division

    2009-03-12

    Control system studies were performed for the Next Generation Nuclear Plant (NGNP) interfaced to the High Temperature Electrolysis (HTE) plant. Temperature change and associated thermal stresses are important factors in determining plant lifetime. In the NGNP the design objective of a 40 year lifetime for the Intermediate Heat Exchanger (IHX) in particular is seen as a challenge. A control system was designed to minimize temperature changes in the IHX and more generally at all high-temperature locations in the plant for duty-cycle transients. In the NGNP this includes structures at the reactor outlet and at the inlet to the turbine. This problem was approached by identifying those high-level factors that determine temperature rates of change. First are the set of duty cycle transients over which the control engineer has little control but which none-the-less must be addressed. Second is the partitioning of the temperature response into a quasi-static component and a transient component. These two components are largely independent of each other and when addressed as such greater understanding of temperature change mechanisms and how to deal with them is achieved. Third is the manner in which energy and mass flow rates are managed. Generally one aims for a temperature distribution that minimizes spatial non-uniformity of thermal expansion in a component with time. This is can be achieved by maintaining a fixed spatial temperature distribution in a component during transients. A general rule of thumb for heat exchangers is to maintain flow rate proportional to thermal power. Additionally the product of instantaneous flow rate and heat capacity should be maintained the same on both sides of the heat exchanger. Fourth inherent mechanisms for stable behavior should not be compromised by active controllers that can introduce new feedback paths and potentially create under-damped response. Applications of these principles to the development of a plant control strategy for

  2. 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.

  3. Controlled Chemistry Helium High Temperature Materials Test Loop

    SciTech Connect

    Richard N. WRight

    2005-08-01

    A system to test aging and environmental effects in flowing helium with impurity content representative of the Next Generation Nuclear Plant (NGNP) has been designed and assembled. The system will be used to expose microstructure analysis coupons and mechanical test specimens for up to 5,000 hours in helium containing potentially oxidizing or carburizing impurities controlled to parts per million levels. Impurity levels in the flowing helium are controlled through a feedback mechanism based on gas chromatography measurements of the gas chemistry at the inlet and exit from a high temperature retort containing the test materials. Initial testing will focus on determining the nature and extent of combined aging and environmental effects on microstructure and elevated temperature mechanical properties of alloys proposed for structural applications in the NGNP, including Inconel 617 and Haynes 230.

  4. Design and optimization of organic rankine cycle for low temperature geothermal power plant

    NASA Astrophysics Data System (ADS)

    Barse, Kirtipal A.

    Rising oil prices and environmental concerns have increased attention to renewable energy. Geothermal energy is a very attractive source of renewable energy. Although low temperature resources (90°C to 150°C) are the most common and most abundant source of geothermal energy, they were not considered economical and technologically feasible for commercial power generation. Organic Rankine Cycle (ORC) technology makes it feasible to use low temperature resources to generate power by using low boiling temperature organic liquids. The first hypothesis for this research is that using ORC is technologically and economically feasible to generate electricity from low temperature geothermal resources. The second hypothesis for this research is redesigning the ORC system for the given resource condition will improve efficiency along with improving economics. ORC model was developed using process simulator and validated with the data obtained from Chena Hot Springs, Alaska. A correlation was observed between the critical temperature of the working fluid and the efficiency for the cycle. Exergy analysis of the cycle revealed that the highest exergy destruction occurs in evaporator followed by condenser, turbine and working fluid pump for the base case scenarios. Performance of ORC was studied using twelve working fluids in base, Internal Heat Exchanger and turbine bleeding constrained and non-constrained configurations. R601a, R245ca, R600 showed highest first and second law efficiency in the non-constrained IHX configuration. The highest net power was observed for R245ca, R601a and R601 working fluids in the non-constrained base configuration. Combined heat exchanger area and size parameter of the turbine showed an increasing trend as the critical temperature of the working fluid decreased. The lowest levelized cost of electricity was observed for R245ca followed by R601a, R236ea in non-constrained base configuration. The next best candidates in terms of LCOE were R601a, R

  5. Solar Array at Very High Temperatures: Ground Tests

    NASA Technical Reports Server (NTRS)

    Vayner, Boris

    2016-01-01

    Solar array design for any spacecraft is determined by the orbit parameters. For example, operational voltage for spacecraft in Low Earth Orbit (LEO) is limited by significant differential charging due to interactions with low temperature plasma. In order to avoid arcing in LEO, solar array is designed to generate electrical power at comparatively low voltages (below 100 V) or to operate at higher voltages with encapsulated of all suspected discharge locations. In Geosynchronous Orbit (GEO) differential charging is caused by energetic electrons that produce differential potential between coverglass and conductive spacecraft body in a kilovolt range. In such a case, weakly conductive layer over coverglass (ITO) is one of possible measures to eliminate dangerous discharges on array surface. Temperature variations for solar arrays in both orbits are measured and documented within the range of -150 C +110 C. This wide interval of operational temperatures is regularly reproduced in ground tests with radiative heating and cooling inside shroud with flowing liquid nitrogen. The requirements to solar array design and tests turn out to be more complicated when planned trajectory crosses these two orbits and goes closer to Sun. Conductive layer over coverglass causes sharp increase in parasitic current collected from LEO plasma, high temperature may cause cracks in encapsulating material (RTV), radiative heating of coupon in vacuum chamber becomes practically impossible above 150 C, conductivities of glass and adhesive go up with temperature that decrease array efficiency, and mechanical stresses grow up to critical magnitudes. A few test arrangements and respective results are presented in current paper. Coupons were tested against arcing in simulated LEO and GEO environments under elevated temperatures up to 200 C. The dependence of leakage current on temperature was measured, and electrostatic cleanness was verified for coupons with antireflection (AR) coating over ITO

  6. Aquarius Reflector Surface Temperature Monitoring Test and Analysis

    NASA Technical Reports Server (NTRS)

    Abbott, Jamie; Lee, Siu-Chun; Becker, Ray

    2008-01-01

    The presentation addresses how to infer the front side temperatures for the Aquarius L-band reflector based upon backside measurement sites. Slides discussing the mission objectives and design details are at the same level found on typical project outreach websites and in conference papers respectively. The test discussion provides modest detail of an ordinary thermal balance test using mockup hardware. The photographs show an off-Lab vacuum chamber facility with no compromising details.

  7. Triaxial testing of polymer concrete materials under different temperature

    SciTech Connect

    Salami, M.R.; Zhao, S.

    1995-06-01

    Since polymer mortar materials are used in construction, there is a need for an accurate material model to predict the behavior of the materials under various loading conditions. To make use of a material failure model, it is necessary to determine the material constants by conducting laboratory tests on material specimens. To find the constants for a failure model the material will be subjected to static load testing at different temperatures and loading rates.

  8. Heat recovery steam generator outlet temperature control system for a combined cycle power plant

    SciTech Connect

    Martens, A.; Myers, G.A.; McCarty, W.L.; Wescott, K.R.

    1986-04-01

    This patent describes a command cycle electrical power plant including: a steam turbine and at least one set comprising a gas turbine, an afterburner and a heat recovery steam generator having an attemperator for supplying from an outlet thereof to the steam turbine superheated steam under steam turbine operating conditions requiring predetermined superheated steam temperature, flow and pressure; with the gas turbine and steam turbine each generating megawatts in accordance with a plant load demand; master control means being provided for controlling the steam turbine and the heat recovery steam generator so as to establish the steam operating conditions; the combination of: first control means responsive to the gas inlet temperature of the heat recovery steam generator and to the plant load demand for controlling the firing of the afterburner; second control means responsive to the superheated steam predetermined temperature and to superheated steam temperature from the outlet for controlling the attemperator between a closed and an open position; the first and second control means being operated concurrently to maintain the superheated steam outlet temperature while controlling the load of the gas turbine independently of the steam turbine operating conditions.

  9. Impact Testing of Stainless Steel Material at Cold Temperatures

    SciTech Connect

    Spencer D. Snow; D. Keith Morton; Robert K. Blandford

    2008-07-01

    Stainless steels are used for the construction of numerous spent nuclear fuel or radioactive material containers that may be subjected to high strains and moderate strain rates during accidental drop events. Mechanical characteristics of these base materials and their welds under dynamic loads in the strain rate range of concern are not well documented. However, a previous paper [1] reported on impact testing and analysis results performed at the Idaho National Laboratory using 304/304L and 316/316L stainless steel base material specimens at room and elevated temperatures. The goal of the work presented herein is to add recently completed impact tensile testing results at -20 degrees F conditions for dual-marked 304/304L and 316/316L stainless steel material specimens (hereafter referred to as 304L and 316L, respectively). Recently completed welded material impact testing at -20 degrees F, room, 300 degrees F, and 600 degrees F is also reported. Utilizing a drop-weight impact test machine and 1/4-inch to 1/2-inch thick dog-bone shaped test specimens, the impact tests achieved strain rates in the 4 to 40 per second range, depending upon the material temperature. Elevated true stress-strain curves for these materials reflecting varying strain rates and temperatures are presented herein.

  10. The Influence of Cognitive Test Anxiety across the Learning-Testing Cycle

    ERIC Educational Resources Information Center

    Cassady, Jerrell C.

    2004-01-01

    This study tested the hypothesized negative impact of cognitive test anxiety in the test preparation, performance, and reflection phases. Data available from the participants (n=124) included test anxiety, study skills, perceived threat of tests, and performance attributions. Preparation phase data revealed, compared to their counterparts, that…

  11. Instrument accurately measures small temperature changes on test surface

    NASA Technical Reports Server (NTRS)

    Harvey, W. D.; Miller, H. B.

    1966-01-01

    Calorimeter apparatus accurately measures very small temperature rises on a test surface subjected to aerodynamic heating. A continuous thin sheet of a sensing material is attached to a base support plate through which a series of holes of known diameter have been drilled for attaching thermocouples to the material.

  12. Seasonal cycle dependence of temperature fluctuations in the atmosphere. Master's thesis

    SciTech Connect

    Tobin, B.F.

    1994-08-01

    The correlation statistics of meteorological fields have been of interest in weather forecasting for many years and are also of interest in climate studies. A better understanding of the seasonal variation of correlation statistics can be used to determine how the seasonal cycle of temperature fluctuations should be simulated in noise-forced energy balance models. It is shown that the length scale does have a seasonal dependence and will have to be handled through the seasonal modulation of other coefficients in noise-forced energy balance models. The temperature field variance and spatial correlation fluctuations exhibit seasonality with fluctuation amplitudes larger in the winter hemisphere and over land masses. Another factor contributing to seasonal differences is the larger solar heating gradient in the winter.

  13. Improved cycling behavior of ZEBRA battery operated at intermediate temperature of 175°C

    SciTech Connect

    Li, Guosheng; Lu, Xiaochuan; Kim, Jin Yong; Lemmon, John P.; Sprenkle, Vincent L.

    2014-03-01

    Operation of sodium-nickel chloride battery at temperatures lower than 200°C reduces cell degradation and improves the cyclability. One of the main technical issues in terms of operating this battery at intermediate temperatures such as 175°C is the poor wettability of molten sodium on β”-alumina solid electrolyte (BASE) causing reduced active area and limited charging . In order to overcome the problem related to poor wettability of Na melt on BASE at 175°C, Pt grid was applied on the anode side of BASE using a screen printing technique. Deeper charging and improved cycling behavior was observed on the cells with metalized BASEs due to extended active area.

  14. Infrared Thermography for Temperature Measurement and Non-Destructive Testing

    PubMed Central

    Usamentiaga, Rubèn; Venegas, Pablo; Guerediaga, Jon; Vega, Laura; Molleda, Julio; Bulnes, Francisco G.

    2014-01-01

    The intensity of the infrared radiation emitted by objects is mainly a function of their temperature. In infrared thermography, this feature is used for multiple purposes: as a health indicator in medical applications, as a sign of malfunction in mechanical and electrical maintenance or as an indicator of heat loss in buildings. This paper presents a review of infrared thermography especially focused on two applications: temperature measurement and non-destructive testing, two of the main fields where infrared thermography-based sensors are used. A general introduction to infrared thermography and the common procedures for temperature measurement and non-destructive testing are presented. Furthermore, developments in these fields and recent advances are reviewed. PMID:25014096

  15. The effect of ambient temperature on gross-efficiency in cycling

    PubMed Central

    De Koning, Jos J.; de Vrijer, Aukje; Wüst, Rob C. I.; Daanen, Hein A. M.; Foster, Carl

    2007-01-01

    Time-trial performance deteriorates in the heat. This might potentially be the result of a temperature-induced decrease in gross-efficiency (GE). The effect of high ambient temperature on GE during cycling will be studied, with the intent of determining if a heat-induced change in GE could account for the performance decrements in time trial exercise found in literature. Ten well-trained male cyclists performed 20-min cycle ergometer exercise at 60% \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ P_{V{\\text{O}}_{{\\text{2max}}} }$$\\end{document} (power output at which VO2max was attained) in a thermo-neutral climate (N) of 15.6 ± 0.3°C, 20.0 ± 10.3% RH and a hot climate (H) of 35.5 ± 0.5°C, 15.5 ± 3.2% RH. GE was calculated based on VO2 and RER. Skin temperature (Tsk), rectal temperature (Tre) and muscle temperature (Tm) (only in H) were measured. GE was 0.9% lower in H compared to N (19.6 ± 1.1% vs. 20.5 ± 1.4%) (P < 0.05). Tsk (33.4 ± 0.6°C vs. 27.7 ± 0.7°C) and Tre (37.4 ± 0.6°C vs. 37.0 ± 0.6°C) were significantly higher in H. Tm was 38.7 ± 1.1°C in H. GE was lower in heat. Tm was not high enough to make mitochondrial leakage a likely explanation for the observed reduced GE. Neither was the increased Tre. Increased skin blood flow might have had a stealing effect on muscular blood flow, and thus impacted GE. Cycling model simulations showed, that the decrease in GE could account for half of the performance decrement. GE decreased in heat to a degree that could explain at least part of the well-established performance decrements in the heat. PMID:17661069

  16. Watts Bar Unit 1 Cycle Zero Power Physics Tests Analysis with VERA-CS

    SciTech Connect

    Gehin, Jess C; Godfrey, Andrew T; Evans, Thomas M; Hamilton, Steven P; Francheschini, F.

    2014-01-01

    The Consortium for Advanced Simulation of Light Water Reactors (CASL) is developing a collection of methods and software products known as VERA, the Virtual Environment for Reactor Applications, including a core simulation capability called VERA-CS. A key milestone for this endeavor is to validate VERA against measurements from operating nuclear power reactors. The first step in validation against plant data is to determine the ability of VERA to accurately simulate the initial startup physics tests for Watts Bar Nuclear Power Station, Unit 1 (WBN1) cycle 1. VERA-CS calculations were performed with the Insilico code developed at ORNL using cross section processing from the SCALE system and the transport capabilities within the Denovo transport code using the SPN method. The calculations were performed with ENDF/B-VII.0 cross sections in 252 groups (collapsed to 23 groups for the 3D transport solution). The key results of the comparison of calculations with measurements include initial criticality, control rod worth critical configurations, control rod worth, differential boron worth, and isothermal temperature reactivity coefficient (ITC). The VERA results for these parameters show good agreement with measurements, with the exception of the ITC, which requires additional investigation. Results are also compared to those obtained with Monte Carlo methods and a current industry core simulator.

  17. Optimum outlet temperature of solar collector for maximum work output for an Otto air-standard cycle with ideal regeneration

    SciTech Connect

    Eldighidy, S.M. )

    1993-09-01

    The optimum solar collector outlet temperature for maximizing the work output for an Otto air-standard cycle with ideal regeneration is investigated. A mathematical model for the energy balance on the solar collector along with the useful work output and the thermal efficiency of the Otto air-standard cycle with ideal regeneration is developed. The optimum solar collector outlet temperature for maximum work output is determined. The effect of radiative and convective heat losses from the solar collector, on the optimum outlet temperature is presented. The results reveal that the highest solar collector outlet temperature and, therefore, greatest Otto cycle efficiency and work output can be attained with the lowest values of radiative and convective heat losses. Moreover, high cycle work output (as a fraction of absorbed solar energy) and high efficiency of an Otto heat engine with ideal regeneration, driven by a solar collector system, can be attained with low compression ratio.

  18. Effects of cure temperature, electron radiation, and thermal cycling on P75/930 composites

    NASA Technical Reports Server (NTRS)

    Funk, Joan G.

    1990-01-01

    Graphite/epoxy composites are candidates for future space structures due to high stiffness and dimensional stability requirements of these structures. Typical graphite/epoxy composites are brittle and have high residual stresses which often result in microcracking during the thermal cycling typical of the space environment. Composite materials used in geosynchronous orbit applications will also be exposed to high levels of radiation. The purpose of the present study was to determine the effects of cure temperature and radiation exposure on the shear strength and thermal cycling-induced microcrack density of a high modulus, 275 F cure epoxy, P75/930. The results from the P75/930 are compared to previously reported data on P75/934 and T300/934 where 934 is a standard 350 F cure epoxy. The results of this study reveal that P75/930 is significantly degraded by total doses of electron radiation greater than 10(exp 8) rads and by thermally cycling between -250 F and 150 F. The P75/930 did not have improved microcrack resistance over the P75/934, and the 930 resin system appears to be more sensitive to electron radiation-induced degradation than the 934 resin system.

  19. Temperature-compensated ultradian rhythms in lower eukaryotes: timers for cell cycles and circadian events?

    PubMed

    Lloyd, D; Edwards, S W

    1987-01-01

    During the cell cycles of synchronous cultures of several different yeasts and protozoa, oscillations in the rate of respiration and of total cellular protein content have been demonstrated. Energy supply (from mitochondrial oxidative phosphorylation) and energy demand (biosynthetic reactions, especially protein accumulation) are closely coupled oscillating systems. Phase correspondence between O2 consumption rates, intracellular ADP pool size, and total cellular protein indicates that it is energetic demand that determines mitochondrial activity (respiratory control in vivo). The dynamics of the coupled oscillators indicate that the rate-determining control circuit operates on a time scale expected of epigenetic reactions (transcription and translation). Thus the energy-yielding reactions are enslaved to the slower time constants of biosynthesis. Temperature compensation indicates a timing function, and a common phase reference point makes subcycles commensurate with the cell cycle. It is suggested that cell-cycle timing, by counting subcycles in growing cells, may become dominated by circadian control in slowly growing natural populations and that the same subcycles may be used for circadian timekeeping. The discontinuous nature of growth suggests extensive and rapid turnover of macromolecular cell components organized in alternating temporal compartments of biosynthetic and degradative processes, reminding us that "Structures are slow processes of long duration, functions are quick processes of short duration" (von Bertalanffy). PMID:3601956

  20. Thermal Cycling Behavior of Zinc Antimonide Thin Films for High Temperature Thermoelectric Power Generation Applications.

    PubMed

    Shim, Hyung Cheoul; Woo, Chang-Su; Han, Seungwoo

    2015-08-19

    The zinc antimonide compound ZnxSby is one of the most efficient thermoelectric materials known at high temperatures due to its exceptional low thermal conductivity. For this reason, it continues to be the focus of active research, especially regarding its glass-like atomic structure. However, before practical use in actual surroundings, such as near a vehicle manifold, it is imperative to analyze the thermal reliability of these materials. Herein, we present the thermal cycling behavior of ZnxSby thin films in nitrogen (N2) purged or ambient atmosphere. ZnxSby thin films were prepared by cosputtering and reached a power factor of 1.39 mW m(-1) K(-2) at 321 °C. We found maximum power factor values gradually decreased in N2 atmosphere due to increasing resistivity with repeated cycling, whereas the specimen in air kept its performance. X-ray diffraction and electron microscopy observations revealed that fluidity of Zn atoms leads to nanoprecipitates, porous morphologies, and even growth of a coating layer or fiber structures on the surface of ZnxSby after repetitive heating and cooling cycles. With this in mind, our results indicate that proper encapsulation of the ZnxSby surface would reduce these unwanted side reactions and the resulting degradation of thermoelectric performance. PMID:26226167

  1. Removing Diurnal Cycle Contamination in Satellite-Derived Tropospheric Temperatures: Understanding Tropical Tropospheric Trend Discrepancies

    NASA Astrophysics Data System (ADS)

    Po-Chedley, S.; Thorsen, T. J.; Fu, Q.

    2014-12-01

    Tropical mid-tropospheric temperature (TMT) time series have been constructed by several independent research teams using satellite microwave sounding unit (MSU) measurements beginning in 1978 and advanced MSU (AMSU) measurements since 1998. Despite careful efforts to homogenize the MSU/AMSU measurements, tropical TMT trends disagree by a factor of three even though each analysis uses the same basic data. Previous studies suggest that the discrepancy in tropical TMT temperature trends is largely caused by differences in both the NOAA-9 warm target factor and diurnal drift corrections used by various teams to homogenize the MSU/AMSU measurements. This work introduces a new observationally-based method for removing biases related to satellite diurnal drift. The method relies on minimizing inter-satellite and inter-node drifts by subtracting out a common diurnal cycle determined via linear regression. It is demonstrated that this method is effective at removing intersatellite biases and biases between the ascending (PM) and descending (AM) node of individual satellites in the TMT time series. After TMT bias correction, the ratio of tropical tropospheric temperature trends relative to surface temperature trends is in accord with the ratio from global climate models. It is shown that bias corrections for diurnal drift based on a climate model produce tropical trends very similar to those from the observationally-based correction, with a trend differences smaller than 0.02 K decade-1. Differences among various TMT datasets are explored further. Tropical trends from this work are comparable to those from the Remote Sensing System (RSS) and NOAA datasets despite small differences. Larger differences between this work and UAH are attributed to differences in the treatment of the NOAA-9 target factor and the UAH diurnal cycle correction.

  2. Testing of molded high temperature plastic actuator road seals for use in advanced aircraft hydraulic systems

    NASA Technical Reports Server (NTRS)

    Waterman, A. W.; Huxford, R. L.; Nelson, W. G.

    1976-01-01

    Molded high temperature plastic first and second stage rod seal elements were evaluated in seal assemblies to determine performance characteristics. These characteristics were compared with the performance of machined seal elements. The 6.35 cm second stage Chevron seal assembly was tested using molded Chevrons fabricated from five molding materials. Impulse screening tests conducted over a range of 311 K to 478 K revealed thermal setting deficiencies in the aromatic polyimide molding materials. Seal elements fabricated from aromatic copolyester materials structurally failed during impulse cycle calibration. Endurance testing of 3.85 million cycles at 450 K using MIL-H-83283 fluid showed poorer seal performance with the unfilled aromatic polyimide material than had been attained with seals machined from Vespel SP-21 material. The 6.35 cm first stage step-cut compression loaded seal ring fabricated from copolyester injection molding material failed structurally during impulse cycle calibration. Molding of complex shape rod seals was shown to be a potentially controllable technique, but additional molding material property testing is recommended.

  3. 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.

  4. High-Speed, High-Temperature Finger Seal Test Evaluated

    NASA Technical Reports Server (NTRS)

    Proctor, Margaret P.

    2003-01-01

    A finger seal, designed and fabricated by Honeywell Engines, Systems and Services, was tested at the NASA Glenn Research Center at surface speeds up to 1200 ft/s, air temperatures up to 1200 F, and pressures across the seal of 75 psid. These are the first test results obtained with NASA s new High-Temperature, High-Speed Turbine Seal Test Rig (see the photograph). The finger seal is an innovative design recently patented by AlliedSignal Engines, which has demonstrated considerably lower leakage than commonly used labyrinth seals and is considerably cheaper than brush seals. The cost to produce finger seals is estimated to be about half of the cost to produce brush seals. Replacing labyrinth seals with fingers seals at locations that have high-pressure drops in gas turbine engines, typically main engine and thrust seals, can reduce air leakage at each location by 50 percent or more. This directly results in a 0.7- to 1.4-percent reduction in specific fuel consumption and a 0.35- to 0.7-percent reduction in direct operating costs . Because the finger seal is a contacting seal, this testing was conducted to address concerns about its heat generation and life capability at the higher speeds and temperatures required for advanced engines. The test results showed that the seal leakage and wear performance are acceptable for advanced engines.

  5. Silicon Carbide Temperature Monitor Measurements at the High Temperature Test Laboratory

    SciTech Connect

    J. L. Rempe; K. G. Condie; D. L. Knudson; L. L. Snead

    2010-01-01

    Silicon carbide (SiC) temperature monitors are now available for use as temperature sensors in Advanced Test Reactor (ATR) irradiation test capsules. Melt wires or paint spots, which are typically used as temperature sensors in ATR static capsules, are limited in that they can only detect whether a single temperature is or is not exceeded. SiC monitors are advantageous because a single monitor can be used to detect for a range of temperatures that may have occurred during irradiation. As part of the efforts initiated by the ATR National Scientific User Facility (NSUF) to make SiC temperature monitors available, a capability was developed to complete post-irradiation evaluations of these monitors. As discussed in this report, the Idaho National Laboratory (INL) selected the resistance measurement approach for detecting peak irradiation temperature from SiC temperature monitors. This document describes the INL efforts to develop the capability to complete these resistance measurements. In addition, the procedure is reported that was developed to assure that high quality measurements are made in a consistent fashion.

  6. The 5200 cycle test of an 8-cm diameter Hg ion thruster

    NASA Technical Reports Server (NTRS)

    Mantenieks, M. A.; Wintucky, E. G.

    1978-01-01

    An accelerated cycle test was conducted in which an 8-cm Engineering Model Thruster (EMT) prototype successfully completed 5200 on-off cycles and a total of more than 1300hours of thruster operation at a 4.5 mN thrust level. Cathode tip heater powers required for starting and keeper voltages remained well within acceptable limits. The discharge chamber utilization and electrical efficiency were nearly constant over the duration of the test. It was concluded that on-off cyclic operation by itself does not appreciably degrade starting capability or performance of the 8-cm EMT.

  7. High-temperature low cycle fatigue behavior of a gray cast iron

    SciTech Connect

    Fan, K.L. He, G.Q.; She, M.; Liu, X.S.; Lu, Q.; Yang, Y.; Tian, D.D.; Shen, Y.

    2014-12-15

    The strain controlled low cycle fatigue properties of the studied gray cast iron for engine cylinder blocks were investigated. At the same total strain amplitude, the low cycle fatigue life of the studied material at 523 K was higher than that at 423 K. The fatigue behavior of the studied material was characterized as cyclic softening at any given total strain amplitude (0.12%–0.24%), which was attributed to fatigue crack initiation and propagation. Moreover, this material exhibited asymmetric hysteresis loops due to the presence of the graphite lamellas. Transmission electron microscopy analysis suggested that cyclic softening was also caused by the interactions of dislocations at 423 K, such as cell structure in ferrite, whereas cyclic softening was related to subgrain boundaries and dislocation climbing at 523 K. Micro-analysis of specimen fracture appearance was conducted in order to obtain the fracture characteristics and crack paths for different strain amplitudes. It showed that the higher the temperature, the rougher the crack face of the examined gray cast iron at the same total strain amplitude. Additionally, the microcracks were readily blunted during growth inside the pearlite matrix at 423 K, whereas the microcracks could easily pass through pearlite matrix along with deflection at 523 K. The results of fatigue experiments consistently showed that fatigue damage for the studied material at 423 K was lower than that at 523 K under any given total strain amplitude. - Highlights: • The low cycle fatigue behavior of the HT250 for engine cylinder blocks was investigated. • TEM investigations were conducted to explain the cyclic deformation response. • The low cycle fatigue cracks of HT250 GCI were studied by SEM. • The fatigue life of the examined material at 523 K is higher than that at 423 K.

  8. Accelerated and real-time geosynchronous life cycling test performance of nickel-hydrogen batteries

    NASA Technical Reports Server (NTRS)

    Green, R. S.

    1985-01-01

    RCA Astro-Electronics currently has four nickel-hydrogen storage battery modules (11 cells each) on test in simulated geosynchronous life cycle regimes. These battery modules are of identical design to those used on the GSTAR (GTE Satellite Corp.) and Spacenet (GTE Spacenet Corp.) communications satellites. The batteries are being tested using an automated test station equipped with computer-controlled environmental chambers and recording equipment. The two battery types, 30 ampere-hours and 40 ampere-hours (GSTAR and Spacenet, respectively), are being electrically cycled using identical 44-day eclipse sequences at 5 C and vary with respect to depth of discharge, recharge ratio, duration of accumulated suntime, and the use of a reconditioning sequence. The test parameters are outlined and the preliminary test data and results are presented.

  9. Modeled Seasonal Variations of Firn Density Induced by Steady State Surface Air Temperature Cycle

    NASA Technical Reports Server (NTRS)

    Jun, Li; Zwally, H. Jay; Koblinsky, Chester J. (Technical Monitor)

    2001-01-01

    Seasonal variations of firn density in ice-sheet firn layers have been attributed to variations in deposition processes or other processes within the upper firn. A recent high-resolution (mm scale) density profile, measured along a 181 m core from Antarctica, showed small-scale density variations with a clear seasonal cycle that apparently was not-related to seasonal variations in deposition or known near-surface processes (Gerland and others 1999). A recent model of surface elevation changes (Zwally and Li, submitted) produced a seasonal variation in firn densification, and explained the seasonal surface elevation changes observed by satellite radar altimeters. In this study, we apply our 1-D time-dependent numerical model of firn densification that includes a temperature-dependent formulation of firn densification based on laboratory measurements of grain growth. The model is driven by a steady-state seasonal surface temperature and a constant accumulation rate appropriate for the measured Antarctic ice core. The modeled seasonal variations in firn density show that the layers of snow deposited during spring to mid-summer with the highest temperature history compress to the highest density, and the layers deposited during later summer to autumn with the lowest temperature history compress to the lowest density. The initial amplitude of the seasonal difference of about 0.13 reduces to about 0.09 in five years and asymptotically to 0.92 at depth, which is consistent with the core measurements.

  10. Influence of temperature cycling on the production of aflatoxins B1 and G1 by Aspergillus parasiticus.

    PubMed Central

    Lin, Y C; Ayres, J C; Koehler, P E

    1980-01-01

    The effect of temperature cycling on the relative productions of aflatoxins B1 and G1 by Aspergillus parasiticus NRRL 2999 was studied. The cycling of temperature between 33 and 15 degrees C favored aflatoxin B1 accumulation, whereas cycling between 35 and 15 degrees C favored aflatoxin G1 production. Cultures subjected to temperature cycling between 33 and 25 degrees C at various time intervals changed the relative productions of aflatoxins B1 and G1 drastically. Results obtained with temperature cycling and yeast extract-sucrose medium with ethoxyquin to decrease aflatoxin G1 production suggest that the enzyme system responsible for the conversion of aflatoxin B1 to G1 might be more efficient at 25 degrees C than at 33 degrees C. The possible explanation of the effect of both constant and cycling temperatures on the relative accumulations of aflatoxins B1 and G2 might be through the control of the above enzyme system. The study also showed that greater than 57% of aflatoxin B1, greater than 47% of aflatoxin G1, and greater than 50% of total aflatoxins (B1 plus G1) were in the mycelium by day 10 under both constant and cyclic temperature conditions. PMID:6781404

  11. Probabilistic Material Strength Degradation Model for Inconel 718 Components Subjected to High Temperature, High-Cycle and Low-Cycle Mechanical Fatigue, Creep and Thermal Fatigue Effects

    NASA Technical Reports Server (NTRS)

    Bast, Callie C.; Boyce, Lola

    1995-01-01

    The development of methodology for a probabilistic material strength degradation is described. The probabilistic model, in the form of a postulated randomized multifactor equation, provides for quantification of uncertainty in the lifetime material strength of aerospace propulsion system components subjected to a number of diverse random effects. This model is embodied in the computer program entitled PROMISS, which can include up to eighteen different effects. Presently, the model includes five effects that typically reduce lifetime strength: high temperature, high-cycle mechanical fatigue, low-cycle mechanical fatigue, creep and thermal fatigue. Results, in the form of cumulative distribution functions, illustrated the sensitivity of lifetime strength to any current value of an effect. In addition, verification studies comparing predictions of high-cycle mechanical fatigue and high temperature effects with experiments are presented. Results from this limited verification study strongly supported that material degradation can be represented by randomized multifactor interaction models.

  12. Effects of Hot Rolling on Low-Cycle Fatigue Properties of Zn-22 wt.% Al Alloy at Room Temperature

    NASA Astrophysics Data System (ADS)

    Dong, X. H.; Cao, Q. D.; Ma, S. J.; Han, S. H.; Tang, W.; Zhang, X. P.

    2016-06-01

    The effects of the reduction ratio (RR) on the low-cycle fatigue (LCF) properties of the Zn-22 wt.% Al (Zn-22Al) alloy were investigated. Various grain sizes from 0.68 to 1.13 μm were obtained by controlled RRs. Tensile and LCF tests were carried out at room temperature. Superplasticity and cyclic softening were observed. Strength and ductility of the rolled Zn-22Al alloy increased with the RR, owing to the decrease in its grain size. The RR did not affect the cyclic softening behavior of the alloy. The fatigue life of the alloy decreased with increasing strain amplitude, while the fatigue life first decreased and then increased with increasing RR. The longest fatigue life was observed for the alloy rolled at a RR of 60%. A bilinear Coffin-Manson relationship was observed to hold true for this alloy.

  13. Comparison Testings between Two High-temperature Strain Measurement Systems

    NASA Technical Reports Server (NTRS)

    Lei, J.-F.; Castelli, M. G.; Androjna, D.; Blue, C.; Blue, R.; Lin, R. Y.

    1996-01-01

    An experimental evaluation was conducted at NASA Lewis Research Center to compare and contrast the performance of a newly developed resistance strain gage, the PdCr temperature-compensated wire strain gage, to that of a conventional high-temperature extensometry. The evaluation of the two strain measurement systems was conducted through the application of various thermal and mechanical loading spectra using a high-temperature thermomechanical uniaxial testing system equipped with quartz lamp heating. The purpose of the testing was not only to compare and contrast the two strain sensors but also to investigate the applicability of the PdCr strain gage to the testing environment typically employed when characterizing the high-temperature mechanical behavior of structural materials. Strain measurement capabilities to 8OO C were investigated with a nickel base superalloy IN100 substrate material, and application to titanium matrix composite (TMC) materials was examined with the SCS-6/Ti-15-3 08 system. PdCr strain gages installed by three attachment techniques, namely, flame spraying, spot welding and rapid infrared joining were investigated.

  14. Solar Cycle and Anthropogenic Forcing of Surface-Air Temperature at Armagh Observatory, Northern Ireland

    NASA Technical Reports Server (NTRS)

    Wilson, Robert M.

    2010-01-01

    A comparison of 10-yr moving average (yma) values of Armagh Observatory (Northern Ireland) surface-air temperatures with selected solar cycle indices (sunspot number (SSN) and the Aa geomagnetic index (Aa)), sea-surface temperatures in the Nino 3.4 region, and Mauna Loa carbon dioxide (CO2) (MLCO2) atmospheric concentration measurements reveals a strong correlation (r = 0.686) between the Armagh temperatures and Aa, especially, prior to about 1980 (r = 0.762 over the interval of 1873-1980). For the more recent interval 1963-2003, the strongest correlation (r = 0.877) is between Armagh temperatures and MLCO2 measurements. A bivariate fit using both Aa and Mauna Loa values results in a very strong fit (r = 0.948) for the interval 1963-2003, and a trivariate fit using Aa, SSN, and Mauna Loa values results in a slightly stronger fit (r = 0.952). Atmospheric CO2 concentration now appears to be the stronger driver of Armagh surface-air temperatures. An increase of 2 C above the long-term mean (9.2 C) at Armagh seems inevitable unless unabated increases in anthropogenic atmospheric gases can be curtailed. The present growth in 10-yma Armagh temperatures is about 0.05 C per yr since 1982. The present growth in MLCO2 is about 0.002 ppmv, based on an exponential fit using 10-yma values, although the growth appears to be steepening, thus, increasing the likelihood of deleterious effects attributed to global warming.

  15. Specificity of treadmill and cycle ergometer tests in triathletes, runners and cyclists.

    PubMed

    Basset, F A; Boulay, M R

    2000-02-01

    The objective of this study was to evaluate the viability of using a single test in which cardiorespiratory variables are measured, to establish training guidelines in running and/or cycling training activities. Six triathletes (two females and four males), six runners (two females and four males) and six males cyclists, all with 5.5 years of serious training and still involved in racing, were tested on a treadmill and cycle ergometer. Cardiorespiratory variables [e.g., heart rate (HR), minute ventilation, carbon dioxide output (VCO2)] were calculated relative to fixed percentages of maximal oxygen uptake (VO2max; from 50 to 100%). The entire group of subjects had significantly (P < 0.05) higher values of VO2max on the treadmill compared with the cycle ergometer [mean (SEM) 4.7 (0.8) and 4.4 (0.9) l.min-1, respectively], and differences between tests averaged 10.5% for runners, 6.1% for triathletes and 2.8% for cyclists. A three-way analysis of variance using a 3 x 2 x 6 design (groups x tests x intensities) demonstrated that all factors yielded highly significant F-ratios (P < 0.05) for all variables between tests, even though differences in HR were only 4 beats.min-1. When HR was plotted against a fixed percentage of VO2max, a high correlation was found between tests. These results demonstrate that for triathletes, cyclists and runners, the relationship between HR and percentage of VO2max, obtained in either a treadmill or a cycle ergometer test, may be used independently of absolute VO2max to obtain reference HR values that can be used to monitor their running and/or cycling training bouts. PMID:10638380

  16. Evaluation of Electromyographic Frequency Domain Changes during a Three-Minute Maximal Effort Cycling Test.

    PubMed

    Wang, Ran; Fukuda, David H; Stout, Jeffrey R; Robinson, Edward H; Miramonti, Amelia A; Fragala, Maren S; Hoffman, Jay R

    2015-06-01

    To evaluate the time course of EMG frequency changes during a three-minute maximal effort cycling test (3MT) session and to examine which parameter between mean (MNF) and median (MDF) frequency is more suitable for evaluation of changes in neuromuscular function throughout a 3MT. Eighteen recreationally-active men volunteered to participate in this study. Maximum voluntary contraction (MVC) was measured using a dynamometer to determine maximal EMG frequency of the vastus lateralis (VL) of the kicking leg during isometric knee extension. A maximal oxygen consumption test (VO2peak) on a cycle ergometer was performed to establish the appropriate load profile for the 3MT which was completed after a period of at least 48 hours. MNF, MDF and power output (PO) values were measured at 10-second epochs throughout the duration of the 3MT. Repeated measures analysis of variance was used to compare the changes in EMG frequency, relative to maximal values from the MVC, and change in PO during the testing procedure. MNF, Root Mean Square (RMS), and PO significantly decreased during the 3MT, while MDF did not change significantly. Statistically, EMG frequency and PO decreased at first and remained constant in response to the 3MT, which may be reflective of differing patterns of muscle fiber type fatigue throughout the testing session. Due to decreased variability, changes in neuromuscular function during this protocol may be better evaluated using MNF than MDF. Key pointsEMG frequency decreased initially and remained constant in response to all-out cycling test.The change in EMG frequency and power output were similar during all-out cycling test.MNF may be better than MDF for neuromuscular function evaluation during all-out cycling test due to decreased variability. PMID:25983596

  17. Evaluation of Electromyographic Frequency Domain Changes during a Three-Minute Maximal Effort Cycling Test

    PubMed Central

    Wang, Ran; Fukuda, David H.; Stout, Jeffrey R.; Robinson, Edward H.; Miramonti, Amelia A.; Fragala, Maren S.; Hoffman, Jay R.

    2015-01-01

    To evaluate the time course of EMG frequency changes during a three-minute maximal effort cycling test (3MT) session and to examine which parameter between mean (MNF) and median (MDF) frequency is more suitable for evaluation of changes in neuromuscular function throughout a 3MT. Eighteen recreationally-active men volunteered to participate in this study. Maximum voluntary contraction (MVC) was measured using a dynamometer to determine maximal EMG frequency of the vastus lateralis (VL) of the kicking leg during isometric knee extension. A maximal oxygen consumption test (VO2peak) on a cycle ergometer was performed to establish the appropriate load profile for the 3MT which was completed after a period of at least 48 hours. MNF, MDF and power output (PO) values were measured at 10-second epochs throughout the duration of the 3MT. Repeated measures analysis of variance was used to compare the changes in EMG frequency, relative to maximal values from the MVC, and change in PO during the testing procedure. MNF, Root Mean Square (RMS), and PO significantly decreased during the 3MT, while MDF did not change significantly. Statistically, EMG frequency and PO decreased at first and remained constant in response to the 3MT, which may be reflective of differing patterns of muscle fiber type fatigue throughout the testing session. Due to decreased variability, changes in neuromuscular function during this protocol may be better evaluated using MNF than MDF. Key points EMG frequency decreased initially and remained constant in response to all-out cycling test. The change in EMG frequency and power output were similar during all-out cycling test. MNF may be better than MDF for neuromuscular function evaluation during all-out cycling test due to decreased variability. PMID:25983596

  18. Effects of temperature on type approval testing of ballast water treatment systems.

    PubMed

    Drillet, Guillaume; Schmoker, Claire; Trottet, Aurore; Mahjoub, Mohamed-Sofiane; Duchemin, Matthieu; Andersen, Martin

    2013-04-01

    To limit the risk associated with invasion of habitats by exogenous species, the International Convention for the Control and Management of the Ships' Ballast Water and Sediments was adopted in February 2004 and may soon enter into force. The International Maritime Organization (IMO) has produced guidelines to assess the efficacy and reliability of Ballast Water Treatment Systems (BWTS), but no guidance on how to take temperature into account during test cycles has been provided yet. Temperature is one of the main factors influencing the distribution and ecology of organisms along latitudes. Its increase results in higher grazing, growth, and reproduction rates of zooplankton. Under dark conditions, phytoplankton loss is also increased due to faster natural decay as well as enhanced top down control from zooplankton. Increased temperatures also improve the efficacy of chemical treatment, whereas the decay rates of disinfectants and their byproducts are potentially accelerated. The IMO guidelines for the type approval of BWTS should be amended to include recommendations on how to take temperature into account. Failing to ensure comparability and reliability between tests may pose a threat to the environment and may create problems for those attempting to apply BWTS. We propose to use a fixed Q10 value and a temperature of reference to adjust the retention time in ballast water tanks during testing. PMID:23307338

  19. 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.

  20. Results of deep DoD life cycle tests at high rates on 12Ah NiCd cells

    NASA Technical Reports Server (NTRS)

    Panneton, Paul E.; Meyer, John R.

    1992-01-01

    A 12 Ah Nickel-Cadmium (NiCd) Low Earth Orbit (LEO) life cycle test that induced 47 percent more deep Depth Of Discharge cycles by mixing them with shallow DOD cycles is discussed. The test showed how aggressive recharging to a C/D ratio of 1.15 nearly doubled performance over cycling below a C/D of 1.11.

  1. Engine test for wavelength-multiplexed fiber Bragg grating temperature sensor

    NASA Astrophysics Data System (ADS)

    Yu, Li; Wang, Dorothy Y.; Wang, Yunmiao; Collins, Christopher M.; Schneck, William C.; Bailey, Justin M.; O'Brien, Walter F.; Wang, Anbo

    2013-05-01

    A temperature sensor link based on wavelength-multiplexed fiber Bragg grating (FBG) was designed and fabricated for distributed temperature measurement in a jet engine nozzle under field conditions. Eight FBGs with different Bragg wavelengths ranging from 1520 nm to 1560 nm were fabricated along one single-mode fiber which was packaged inside a stainless steel tube. The reflected signal from the sensor link was simultaneously collected by an optical sensing interrogator and converted into temperature information. The steel tube was embedded in a steel flange assembly attached to a jet engine. Three engine cycles were performed from 55% (idle) to 80% of the engine's full power to test the sensor response under high temperature, vibration and strong exhaust flow conditions. Test results show good survivability of the sensor, and the temperature around the nozzle was measured up to 290 °C. The system has a temperature measurement range from 20 °C to 600 ° and the response time is less than 1 second.

  2. Hanford coring bit temperature monitor development testing results report

    SciTech Connect

    Rey, D.

    1995-05-01

    Instrumentation which directly monitors the temperature of a coring bit used to retrieve core samples of high level nuclear waste stored in tanks at Hanford was developed at Sandia National Laboratories. Monitoring the temperature of the coring bit is desired to enhance the safety of the coring operations. A unique application of mature technologies was used to accomplish the measurement. This report documents the results of development testing performed at Sandia to assure the instrumentation will withstand the severe environments present in the waste tanks.

  3. A High Temperature Cyclic Oxidation Data Base for Selected Materials Tested at NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Barrett, Charles A.

    2003-01-01

    The cyclic oxidation test results for some 1000 high temperature commercial and experimental alloys have been collected in an EXCEL database. This database represents over thirty years of research at NASA Glenn Research Center in Cleveland, Ohio. The data is in the form of a series of runs of specific weight change versus time values for a set of samples tested at a given temperature, cycle time, and exposure time. Included on each run is a set of embedded plots of the critical data. The nature of the data is discussed along with analysis of the cyclic oxidation process. In addition examples are given as to how a set of results can be analyzed. The data is assembled on a read-only compact disk which is available on request from Materials Durability Branch, NASA Glenn Research Center, Cleveland, Ohio.

  4. Reliability and field testing of distributed strain and temperature sensors

    NASA Astrophysics Data System (ADS)

    Inaudi, Daniele; Glisic, Branko

    2006-03-01

    Distributed fiber optic sensing presents unique features that have no match in conventional sensing techniques. The ability to measure temperatures and strain at thousands of points along a single fiber is particularly interesting for the monitoring of large structures such as pipelines, flow lines, oil wells, dams and dikes. Sensing systems based on Brillouin and Raman scattering have been used for example to detect pipeline leakages, verify pipeline operational parameters, prevent failure of pipelines installed in landslide areas, optimize oil production from wells and detect hot-spots in high-power cables. The measurement instruments have been vastly improved in terms of spatial, temperature and strain resolution, distance range, measurement time, data processing and system cost. Analyzers for Brillouin and Raman scattering are now commercially available and offer reliable operation in field conditions. New application opportunities have however demonstrated that the design and production of sensing cables is a critical element for the success of any distributed sensing instrumentation project. Although standard telecommunication cables can be effectively used for sensing ordinary temperatures, monitoring high and low temperatures or distributed strain present unique challenges that require specific cable designs. This contribution presents three cable designs for high-temperature sensing, strain sensing and combined strain and temperature monitoring as well as the respective testing procedures during production and in the field.

  5. EFFECTS OF TEST TEMPERATURE ON FLOW OF METALLIC GLASSES

    SciTech Connect

    A.S. NOURI; Y. LIU; P. WESSELING; J. LEWANDOWSKI

    2006-04-12

    Micro-hardness experiments were conducted over a range of temperatures using a Nikon QM micro-hardness machine on a number of metallic glass (e.g. Zr-, Fe-, Al-) systems. Although high micro-hardness was exhibited at room temperature, significant hardness reductions were exhibited near the glass transition temperature, T{sub g}. The effects of changes in test temperature on the micro-hardness will be reported. The effects of exposure time on the hardness evolution at a given temperature will also be summarized to illustrate some of the differences in behavior of the systems shown. The extreme softening near T{sub g}, characteristic of bulk metallic glass systems, enables the exploration of novel deformation processing. In order to develop deformation processing windows, the evaluation of bulk metallic glass mechanical properties under quasi-static conditions and the determination of flow properties at different temperatures and strain rates are reported. The use of such information to create layered/composite bulk metallic glasses will be summarized.

  6. Simulated Lunar Testing of Metabolic Heat Regenerated Temperature Swing Adsorption Technology

    NASA Technical Reports Server (NTRS)

    Padilla, Sebastian A.; Bower, Chad; Iacomini, Christie S.; Paul, H.

    2011-01-01

    Metabolic heat regenerated Temperature Swing Adsorption (MTSA) technology is being developed for thermal and carbon dioxide (CO2) control for a Portable Life Support System (PLSS), as well as water recycling. An Engineering Development Unit (EDU) of the MTSA subassembly was designed and assembled for optimized Martian operations, but also meets system requirements for lunar operations. For lunar operations the MTSA sorption cycle is driven via a vacuum swing between suit ventilation loop pressure and lunar vacuum. The focus of this effort is operations and testing in a simulated lunar environment. This environment was simulated in Paragon s EHF vacuum chamber. The objective of this testing was to evaluate the full cycle performance of the MTSA Subassembly EDU, and to assess CO2 loading and pressure drop of the wash coated aluminum reticulated foam sorbent bed. The lunar testing proved out the feasibility of pure vacuum swing operation, making MTSA a technology that can be tested and used on the Moon prior to going to Mars. Testing demonstrated better than expected CO2 loading on the sorbent and nearly replicates the equilibrium data from the sorbent manufacturer. This had not been achieved in any of the previous sorbent loading tests performed by Paragon. Subsequently, the increased performance of the sorbent bed design indicates future designs will require less mass and volume than the current EDU rendering MTSA as very competitive for Martian PLSS applications.

  7. Low Temperature, Rapid Thermal Cycle Annealing of HgCdTe Grown on CdTe/Si

    NASA Astrophysics Data System (ADS)

    Simingalam, Sina; Brill, Gregory; Wijewarnasuriya, Priyalal; Rao, Mulpuri V.

    2015-05-01

    The HgCdTe(MCT) grown on CdTe/Si substrate has a high dislocation density due to lattice mismatch. Thermal cycle annealing (TCA) is effective in reducing the dislocation density. The TCA at high temperatures results in inter-diffusion of the constituent elements across the MCT/CdTe interface. In this study, we observed a reduction in dislocation density with good surface morphology due to proper design of the TCA system, low annealing temperature, and large number of annealing cycles. The ampoule containing the samples is placed in direct contact with the graphite heating tube which helps in increasing the heating and cooling rates of the annealing cycle. To maintain Hg overpressure, Hg is placed in the sample holder, instead of in the ampoule to avoid Hg condensation. The best results were obtained by cycling the annealing temperature between 290°C and 350°C. Anneals were performed by using 32, 64, 128 and 256 cycles. We obtained an etch pit density (EPD) as low as 1 × 106 cm-2. Lower EPD was not achieved either by increasing annealing temperature or number of annealing cycles. Through secondary ion mass spectroscopy analysis, we observed very little inter-diffusion of Cd across the MCT/CdTe interface for the 128 cycle annealing. These results show promise in bridging the gap in the device performance between the MCT material grown on CdTe/Si and CdZnTe substrates.

  8. CORRELATION BETWEEN THE 22-YEAR SOLAR MAGNETIC CYCLE AND THE 22-YEAR QUASICYCLE IN THE EARTH'S ATMOSPHERIC TEMPERATURE

    SciTech Connect

    Qu Weizheng; Zhao Jinping; Huang Fei; Deng Shenggui

    2012-07-15

    According to the variation pattern of the solar magnetic field polarity and its relation to the relative sunspot number, we established the time series of the sunspot magnetic field polarity index and analyzed the strength and polarity cycle characteristics of the solar magnetic field. The analysis showed the existence of a cycle with about a 22-year periodicity in the strength and polarity of the solar magnetic field, which proved the Hale proposition that the 11-year sunspot cycle is one-half of the 22-year solar magnetic cycle. By analyzing the atmospheric temperature field, we found that the troposphere and the stratosphere in the middle latitude of both the northern and southern hemispheres exhibited a common 22-year quasicycle in the atmospheric temperature, which is believed to be attributable to the 22-year solar magnetic cycle.

  9. GEO And LEO Life Tests Of Saft Lithium Ion Batteries After Ten Years Of Cycling

    NASA Astrophysics Data System (ADS)

    Dudley, G.; Hendel, B.; Borthomieu, Y.

    2011-10-01

    In the period 1999 - 2000 several life tests were started to support the qualification of the SAFT VES140 S lithium ion cell for GEO and LEO applications. Most are still continuing and all have demonstrated excellent performance. For example a real-time GEO test after the equivalent of 10 years in orbit shows a cell internal resistance increase of less than 20% and the cell capacity and energy are still higher than the values measured after the first season.Accelerated GEO tests have reached 90 seasons. A real-time LEO test has exceeded 48000 cycles at 30% depth of discharge (DoD) and 108000 cycles under an accelerated variable DoD profile of between 10 and 30 %. The evolution of performance will be described and in particular measurements of cell internal resistance and can strain.

  10. Elevated Temperature Testing and Modeling of Advanced Toughened Ceramic Materials

    NASA Technical Reports Server (NTRS)

    Keith, Theo G.

    2005-01-01

    The purpose of this report is to provide a final report for the period of 12/1/03 through 11/30/04 for NASA Cooperative Agreement NCC3-776, entitled "Elevated Temperature Testing and Modeling of Advanced Toughened Ceramic Materials." During this final period, major efforts were focused on both the determination of mechanical properties of advanced ceramic materials and the development of mechanical test methodologies under several different programs of the NASA-Glenn. The important research activities made during this period are: 1. Mechanical properties evaluation of two gas-turbine grade silicon nitrides. 2) Mechanical testing for fuel-cell seal materials. 3) Mechanical properties evaluation of thermal barrier coatings and CFCCs and 4) Foreign object damage (FOD) testing.

  11. High-temperature acoustic test facilities and methods

    NASA Astrophysics Data System (ADS)

    Pearson, Jerome

    1994-09-01

    The Wright Laboratory is the Air Force center for air vehicles, responsible for developing advanced technology and incorporating it into new flight vehicles and for continuous technological improvement of operational air vehicles. Part of that responsibility is the problem of acoustic fatigue. With the advent of jet aircraft in the 1950's, acoustic fatigue of aircraft structure became a significant problem. In the 1960's the Wright Laboratory constructed the first large acoustic fatigue test facilities in the United States, and the laboratory has been a dominant factor in high-intensity acoustic testing since that time. This paper discusses some of the intense environments encountered by new and planned Air Force flight vehicles, and describes three new acoustic test facilities of the Wright Laboratory designed for testing structures in these dynamic environments. These new test facilities represent the state of the art in high-temperature, high-intensity acoustic testing and random fatigue testing. They will allow the laboratory scientists and engineers to test the new structures and materials required to withstand the severe environments of captive-carry missiles, augmented lift wings and flaps, exhaust structures of stealth aircraft, and hypersonic vehicle structures well into the twenty-first century.

  12. Impact Tensile Testing of Stainless Steels at Various Temperatures

    SciTech Connect

    D. K. Morton

    2008-03-01

    Stainless steels are used for the construction of numerous spent nuclear fuel or radioactive material containers that may be subjected to high strains and moderate strain rates during accidental drop events. Mechanical characteristics of these base materials and their welds under dynamic loads in the strain rate range of concern (1 to 300 per second) are not well documented. However, research is being performed at the Idaho National Laboratory to quantify these characteristics. The work presented herein discusses tensile impact testing of dual-marked 304/304L and 316/316L stainless steel material specimens. Both base material and welded material specimens were tested at -20 oF, room temperature, 300 oF, and 600 oF conditions. Utilizing a drop weight impact test machine and 1/4-inch and 1/2-inch thick dog bone-shaped test specimens, a strain rate range of approximately 4 to 40 per second (depending on initial temperature conditions) was achieved. Factors were determined that reflect the amount of increased strain energy the material can absorb due to strain rate effects. Using the factors, elevated true stress-strain curves for these materials at various strain rates and temperatures were generated. By incorporating the strain rate elevated true stress-strain material curves into an inelastic finite element computer program as the defined material input, significant improvement in the accuracy of the computer analyses was attained. However, additional impact testing is necessary to achieve higher strain rates (up to 300 per second) before complete definition of strain rate effects can be made for accidental drop events and other similar energy-limited impulsive loads. This research approach, using impact testing and a total energy analysis methodology to quantify strain rate effects, can be applied to many other materials used in government and industry.

  13. EVALUATING AND TESTING EMERGENCY TESTING MONITORING DEVICES IN EXTREME COLD TEMPERATURES

    EPA Science Inventory

    EPA Identifier: F8P11070
    Title: Evaluating and Testing Emergency Testing Monitoring Devices in Extreme Cold Temperatures
    Fellow (Principal Investigator): Tyler S. O’Dell
    Institution: Lake Superior State University
    EPA GRANT Represent...

  14. 40 CFR 86.1362-2007 - Steady-state testing with a ramped-modal cycle.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... in 40 CFR 1065.650 and cycle statistics as described in 40 CFR 1065.514. (b) Measure emissions by... Steady-state 168 Warm Idle 0 1 Speed terms are defined in 40 CFR part 1065. 2 Advance from one mode to... maximum test torque. (d) (e) See 40 CFR part 1065 for detailed specifications of tolerances...

  15. Problem-Based Test: Replication of Mitochondrial DNA during the Cell Cycle

    ERIC Educational Resources Information Center

    Setalo, Gyorgy, Jr.

    2013-01-01

    Terms to be familiar with before you start to solve the test: cell cycle, generation time, S-phase, cell culture synchronization, isotopic pulse-chase labeling, density labeling, equilibrium density-gradient centrifugation, buoyant density, rate-zonal centrifugation, nucleoside, nucleotide, kinase enzymes, polymerization of nucleic acids,…

  16. 40 CFR Appendix E to Subpart S of... - Transient Test Driving Cycle

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 2 2012-07-01 2012-07-01 false Transient Test Driving Cycle E Appendix E to Subpart S of Part 51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANS Inspection/Maintenance Program Requirements Pt. 51, Subpt....

  17. 40 CFR 86.1362-2007 - Steady-state testing with a ramped-modal cycle.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... maximum test torque. (d) (e) See 40 CFR part 1065 for detailed specifications of tolerances and... in 40 CFR 1065.650 and cycle statistics as described in 40 CFR 1065.514. (b) Measure emissions by... Steady-state 168 Warm Idle 0 1 Speed terms are defined in 40 CFR part 1065. 2 Advance from one mode...

  18. 40 CFR 86.1362-2007 - Steady-state testing with a ramped-modal cycle.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... maximum test torque. (d) (e) See 40 CFR part 1065 for detailed specifications of tolerances and... in 40 CFR 1065.650 and cycle statistics as described in 40 CFR 1065.514. (b) Measure emissions by... Steady-state 168 Warm Idle 0 1 Speed terms are defined in 40 CFR part 1065. 2 Advance from one mode...

  19. 40 CFR 86.1362-2007 - Steady-state testing with a ramped-modal cycle.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... maximum test torque. (d) (e) See 40 CFR part 1065 for detailed specifications of tolerances and... in 40 CFR 1065.650 and cycle statistics as described in 40 CFR 1065.514. (b) Measure emissions by... Steady-state 168 Warm Idle 0 1 Speed terms are defined in 40 CFR part 1065. 2 Advance from one mode...

  20. Resynchronization of circadian sleep-wake and temperature cycles in the squirrel monkey following phase shifts of the environmental light-dark cycle

    SciTech Connect

    Wexler, D.B.; Moore-ede, M.C.

    1986-12-01

    Circadian rhythms in physiological and behavioral functions gradually resynchronize after phase shifts in environmental time cues. In order to characterize the rate of circadian resynchronization in a diurnal primate model, the temperature, locomotor activity, and polygraphically determined sleep-wake states were monitored in squirrel monkeys before and after 8-h phase shifts of an environmental light-dark cycle of 12 h light and 12 h dark (LD 12:12). For the temperature rhythm, resynchronization took 4 d after phase delay shift and 5 d after phase advance shift; for the rest-activity cycle, resynchronization times were 3 d and 6 d, respectively. The activity acrophase shifted more rapidly than the temperature acrophase early in the post-delay shift interval, but this internal desynchronization between rhythms disappeared during the course of resynchronization. Further study of the early resynchronization process requires emphasis on identifying evoked effects and measuring circadian pacemaker function. 13 references.

  1. Fuel-Cycle and Nuclear Material Disposition Issues Associated with High-Temperature Gas Reactors

    SciTech Connect

    Shropshire, D.E.; Herring, J.S.

    2004-10-03

    The objective of this paper is to facilitate a better understanding of the fuel-cycle and nuclear material disposition issues associated with high-temperature gas reactors (HTGRs). This paper reviews the nuclear fuel cycles supporting early and present day gas reactors, and identifies challenges for the advanced fuel cycles and waste management systems supporting the next generation of HTGRs, including the Very High Temperature Reactor, which is under development in the Generation IV Program. The earliest gas-cooled reactors were the carbon dioxide (CO2)-cooled reactors. Historical experience is available from over 1,000 reactor-years of operation from 52 electricity-generating, CO2-cooled reactor plants that were placed in operation worldwide. Following the CO2 reactor development, seven HTGR plants were built and operated. The HTGR came about from the combination of helium coolant and graphite moderator. Helium was used instead of air or CO2 as the coolant. The helium gas has a significant technical base due to the experience gained in the United States from the 40-MWe Peach Bottom and 330-MWe Fort St. Vrain reactors designed by General Atomics. Germany also built and operated the 15-MWe Arbeitsgemeinschaft Versuchsreaktor (AVR) and the 300-MWe Thorium High-Temperature Reactor (THTR) power plants. The AVR, THTR, Peach Bottom and Fort St. Vrain all used fuel containing thorium in various forms (i.e., carbides, oxides, thorium particles) and mixtures with highly enriched uranium. The operational experience gained from these early gas reactors can be applied to the next generation of nuclear power systems. HTGR systems are being developed in South Africa, China, Japan, the United States, and Russia. Elements of the HTGR system evaluated included fuel demands on uranium ore mining and milling, conversion, enrichment services, and fuel fabrication; fuel management in-core; spent fuel characteristics affecting fuel recycling and refabrication, fuel handling, interim

  2. Ice surface temperatures: seasonal cycle and daily variability from in-situ and satellite observations

    NASA Astrophysics Data System (ADS)

    Madsen, Kristine S.; Dybkjær, Gorm; Høyer, Jacob L.; Nielsen-Englyst, Pia; Rasmussen, Till A. S.; Tonboe, Rasmus T.

    2016-04-01

    Surface temperature is an important parameter for understanding the climate system, including the Polar Regions. Yet, in-situ temperature measurements over ice- and snow covered regions are sparse and unevenly distributed, and atmospheric circulation models estimating surface temperature may have large biases. To change this picture, we will analyse the seasonal cycle and daily variability of in-situ and satellite observations, and give an example of how to utilize the data in a sea ice model. We have compiled a data set of in-situ surface and 2 m air temperature observations over land ice, snow, sea ice, and from the marginal ice zone. 2523 time series of varying length from 14 data providers, with a total of more than 13 million observations, have been quality controlled and gathered in a uniform format. An overview of this data set will be presented. In addition, IST satellite observations have been processed from the Metop/AVHRR sensor and a merged analysis product has been constructed based upon the Metop/AVHRR, IASI and Modis IST observations. The satellite and in-situ observations of IST are analysed in parallel, to characterize the IST variability on diurnal and seasonal scales and its spatial patterns. The in-situ data are used to estimate sampling effects within the satellite observations and the good coverage of the satellite observations are used to complete the geographical variability. As an example of the application of satellite IST data, results will be shown from a coupled HYCOM-CICE ocean and sea ice model run, where the IST products have been ingested. The impact of using IST in models will be assessed. This work is a part of the EUSTACE project under Horizon 2020, where the ice surface temperatures form an important piece of the puzzle of creating an observationally based record of surface temperatures for all corners of the Earth, and of the ESA GlobTemperature project which aims at applying surface temperatures in models in order to

  3. Changes in seasonal and diurnal cycles of ozone and temperature in the eastern U.S.

    NASA Astrophysics Data System (ADS)

    Bloomer, Bryan J.; Vinnikov, Konstantin Y.; Dickerson, Russell R.

    2010-07-01

    The pollutant tropospheric ozone causes human health problems, and environmental degradation and acts as a potent greenhouse gas. Using long-term hourly observations at five US air quality monitoring surface stations we studied the seasonal and diel cycles of ozone concentrations and surface air temperature to examine the temporal evolution over the past two decades. Such an approach allows visualizing the impact of natural and anthropogenic processes on ozone; nocturnal inversion development, photochemistry, and stratospheric intrusion. Analysis of the result provides an option for determining the duration for a regulatory ozone season. The application of the method provides independent confirmation of observed changes and trends in the ozone and temperature data records as reported elsewhere. The results provide further evidence supporting the assertion that ozone reductions can be attributed to emission reductions as opposed to weather variation. Despite a (˜0.5 °C decade -1) daytime warming trend, ozone decreased by up to 6 ppb decade -1 during times of maximum temperature in the most polluted locations. Ozone also decreased across the emission reduction threshold of 2002 by 6-10 ppb indicating that emission reductions have been effective where and when it is most needed. Longer time series, and coupling with other data sources, may allow for the direct investigation of climate change influence on regional ozone air pollution formation and destruction over annual and daily time scales.

  4. Weekly cycles in peak time temperatures and urban heat island intensity

    NASA Astrophysics Data System (ADS)

    Earl, Nick; Simmonds, Ian; Tapper, Nigel

    2016-07-01

    Regular diurnal and weekly cycles (WCs) in temperature provide valuable insights into the consequences of anthropogenic activity on the urban environment. Different locations experience a range of identified WCs and have very different structures. Two important sources of urban heat are those associated with the effect of large urban structures on the radiation budget and energy storage and those from the heat generated as a consequence of anthropogenic activity. The former forcing will remain relatively constant, but a WC will appear in the latter. WCs for specific times of day and the urban heat island (UHI) have not been analysed heretofore. We use three-hourly surface (2 m) temperature data to analyse the WCs of seven major Australian cities at different times of day and to determine to what extent one of our major city’s (Melbourne) UHI exhibits a WC. We show that the WC of temperature in major cities differs according to the time of day and that the UHI intensity of Melbourne is affected on a WC. This provides crucial information that can contribute toward the push for healthier urban environments in the face of a more extreme climate.

  5. HYBRID SULFUR CYCLE FLOWSHEETS FOR HYDROGEN PRODUCTION USING HIGH-TEMPERATURE GAS-COOLED REACTORS

    SciTech Connect

    Gorensek, M.

    2011-07-06

    Two hybrid sulfur (HyS) cycle process flowsheets intended for use with high-temperature gas-cooled reactors (HTGRs) are presented. The flowsheets were developed for the Next Generation Nuclear Plant (NGNP) program, and couple a proton exchange membrane (PEM) electrolyzer for the SO2-depolarized electrolysis step with a silicon carbide bayonet reactor for the high-temperature decomposition step. One presumes an HTGR reactor outlet temperature (ROT) of 950 C, the other 750 C. Performance was improved (over earlier flowsheets) by assuming that use of a more acid-tolerant PEM, like acid-doped poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole] (PBI), instead of Nafion{reg_sign}, would allow higher anolyte acid concentrations. Lower ROT was accommodated by adding a direct contact exchange/quench column upstream from the bayonet reactor and dropping the decomposition pressure. Aspen Plus was used to develop material and energy balances. A net thermal efficiency of 44.0% to 47.6%, higher heating value basis is projected for the 950 C case, dropping to 39.9% for the 750 C case.

  6. 30 CFR 7.47 - Deflection temperature test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... which are 4 inches apart and immersed in a heat transfer medium at a test temperature range of 65 °F−80 °F (18.3 °C−26.7 °C). The heat transfer medium must be a liquid which will not chemically affect the... an accuracy of 1% into the heat transfer medium within 1/8 inch of, but not touching, the sample....

  7. 30 CFR 7.47 - Deflection temperature test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... which are 4 inches apart and immersed in a heat transfer medium at a test temperature range of 65 °F−80 °F (18.3 °C−26.7 °C). The heat transfer medium must be a liquid which will not chemically affect the... an accuracy of 1% into the heat transfer medium within 1/8 inch of, but not touching, the sample....

  8. Optical strain measuring techniques for high temperature tensile testing

    NASA Technical Reports Server (NTRS)

    Gyekenyesi, John Z.; Hemann, John H.

    1987-01-01

    A number of optical techniques used for the analysis of in-plane displacements or strains are reviewed. The application would be for the high temperature, approximately 1430 C (2600 F), tensile testing of ceramic composites in an oxidizing atmosphere. General descriptions of the various techniques and specifics such as gauge lengths and sensitivities are noted. Also, possible problems with the use of each method in the given application are discussed.

  9. The University of Minnesota aquifer thermal energy storage (ATES) field test facility -- system description, aquifer characterization, and results of short-term test cycles

    SciTech Connect

    Walton, M.; Hoyer, M.C.; Eisenreich, S.J.; Holm, N.L.; Holm, T.R.; Kanivetsky, R.; Jirsa, M.A.; Lee, H.C.; Lauer, J.L.; Miller, R.T.; Norton, J.L.; Runke, H. )

    1991-06-01

    Phase 1 of the Aquifer Thermal Energy Storage (ATES) Project at the University of Minnesota was to test the feasibility, and model, the ATES concept at temperatures above 100{degrees}C using a confined aquifer for the storage and recovery of hot water. Phase 1 included design, construction, and operation of a 5-MW thermal input/output field test facility (FTF) for four short-term ATES cycles (8 days each of heat injection, storage, and heat recover). Phase 1 was conducted from May 1980 to December 1983. This report describes the FTF, the Franconia-Ironton-Galesville (FIG) aquifer used for the test, and the four short-term ATES cycles. Heat recovery; operational experience; and thermal, chemical, hydrologic, and geologic effects are all included. The FTF consists of monitoring wells and the source and storage well doublet completed in the FIG aquifer with heat exchangers and a fixed-bed precipitator between the wells of the doublet. The FIG aquifer is highly layered and a really anisotropic. The upper Franconia and Ironton-Galesville parts of the aquifer, those parts screened, have hydraulic conductivities of {approximately}0.6 and {approximately}1.0 m/d, respectively. Primary ions in the ambient ground water are calcium and magnesium bicarbonate. Ambient temperature FIG ground water is saturated with respect to calcium/magnesium bicarbonate. Heating the ground water caused most of the dissolved calcium to precipitate out as calcium carbonate in the heat exchanger and precipitator. Silica, calcium, and magnesium were significantly higher in recovered water than in injected water, suggesting dissolution of some constituents of the aquifer during the cycles. Further work on the ground water chemistry is required to understand water-rock interactions.

  10. Effects of strain rate, test temperature and test environment on tensile properties of vandium alloys

    SciTech Connect

    Gubbi, A.N.; Rowcliffe, A.F.; Eatherly, W.S.; Gibson, L.T.

    1996-10-01

    Tensile testing was carried out on SS-3 tensile specimens punched from 0.762-mm-thick sheets of the large heat of V-4Cr-4Ti and small heats of V-3Cr-3Ti and V-6Cr-6Ti. The tensile specimens were annealed at 1000{degrees} for 2 h to obtain a fully recrystallized, fine grain microstructure with a grain size in the range of 10-19 {mu}m. Room temperature tests at strain rates ranging from 10{sup {minus}3} to 5 x 10{sup {minus}1}/s were carried out in air; elevated temperature testing up to 700{degrees}C was conducted in a vacuum better than 1 x 10{sup {minus}5} torr (<10{sup {minus}3} Pa). To study the effect of atomic hydrogen on ductility, tensile tests were conducted at room temperature in an ultra high vacuum chamber (UHV) with a hydrogen leak system.

  11. 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.

  12. CARS temperature measurements in a hypersonic propulsion test facility

    NASA Technical Reports Server (NTRS)

    Jarrett, O., Jr.; Smith, M. W.; Antcliff, R. R.; Northam, G. B.; Cutler, A. D.

    1990-01-01

    Static-temperature measurements performed in a reacting vitiated air-hydrogen Mach-2 flow in a duct in Test Cell 2 at NASA LaRC by using a coherent anti-Stokes Raman spectroscopy (CARS) system are discussed. The hypersonic propulsion Test Cell 2 hardware is outlined with emphasis on optical access ports and safety features in the design of the Test Cell. Such design considerations as vibration, noise, contamination from flow field or atmospheric-borne dust, unwanted laser- and electrically-induced combustion, and movement of the sampling volume in the flow are presented. The CARS system is described, and focus is placed on the principle and components of system-to-monochromator signal coupling. Contour plots of scramjet combustor static temperature in a reacting-flow region are presented for three stations, and it is noted that the measurements reveal such features in the flow as maximum temperature near the model wall in the region of the injector footprint.

  13. Extracellular matrix remodeling of the testes through the male reproductive cycle in Teleostei fish.

    PubMed

    Santana, Julio Cesar de Oliveira; Quagio-Grassiotto, Irani

    2014-12-01

    During the fish reproductive cycle, testes undergo morphological changes related to germinal epithelium and remodeling of extracellular matrix components (ECM). ECM is degraded mainly by action of matrix metalloproteinases (MMPs). Due to the natural renewal of ECM in fish testes, we choose Pimelodus maculatus to study remodeling of ECM throughout reproductive cycle, using picrosirius (to identify type I, II, III collagen) and reticulin (type III collagen), and to immunolocalize MT1-MMP (membrane type 1-matrix metalloproteinase) and MMP-2 in testis cells. Testes were classified in four reproductive phases: regenerating, development, spawning capable and regressing. Picrosirius and reticulin demonstrated a differential distribution of total collagen fibers during the reproductive cycle. Immunohistochemistry showed MT1-MMP only in acidophilic granulocyte cells mainly inside blood vessels, in connective tissue of capsule close to the germinal compartment, and also infiltrated in interstitial connective tissue. MMP-2 was detected in fibroblast and endothelial cells of interstitial and capsule blood vessels, in epithelial cells of capsule, and in acidophilic granulocyte cells at same description for MT1-MMP. The fish testes ECM were remodeled throughout reproductive cycle in according to morphophysiological alterations. During reproductive season (spawning capable), the interstitium increased in total collagen fibers (type I, II, III). After spermiation period (regression and regenerating), the amount of collagen fibers decreased in response to action of MMPs on collagen degradation and other interstitial components (not assessed in this study). MMPs seem to be indispensable components for natural cyclic events of ECM remodeling of fish testes and for guarantee tissue homeostasis throughout reproductive cycle. PMID:25142725

  14. Comparison of online and offline tests in LED accelerated reliability tests under temperature stress.

    PubMed

    Ke, Hong-Liang; Jing, Lei; Gao, Qun; Wang, Yao; Hao, Jian; Sun, Qiang; Xu, Zhi-Jun

    2015-11-20

    Accelerated aging tests are the main method used in the evaluation of LED reliability, and can be performed in either online or offline modes. The goal of this study is to provide the difference between the two test modes. In the experiments, the sample is attached to different heat sinks to acquire the optical parameters under different junction temperatures of LEDs. By measuring the junction temperature in the aging process (Tj1), and the junction temperature in the testing process (Tj2), we achieve consistency with an online test of Tj1 and Tj2 and a difference with an offline test of Tj1 and Tj2. Experimental results show that the degradation rate of the luminous flux rises as Tj2 increases, which yields a difference of projected life L(70%) of 8% to 13%. For color shifts over 5000 h of aging, the online test shows a larger variation of the distance from the Planckian locus, about 40% to 50% more than the normal test at an ambient temperature of 25°C. PMID:26836556

  15. High temperature electrolyzer/fuel cell power cycle: Preliminary design considerations

    NASA Technical Reports Server (NTRS)

    Morehouse, Jeffrey H.

    1987-01-01

    A model of a high temperature electrolyzer/fuel cell, hydrogen/oxygen, thermally regenerative power cycle is developed and used to simulate system performance for varying system parameters. Initial estimates of system efficiency, weight, and volume are provided for a one KWe module assuming specific electrolyzer and fuel cell characteristics, both current and future. Specific interest is placed on examining the system responses to changes in device voltage versus current density operating curves, and the associated optimum operating ranges. The performance of a solar-powered, space based system in low earth orbit is examined in terms of the light-dark periods requiring storage. The storage design tradeoffs between thermal energy, electrical energy, and hydrogen/oxygen mass storage are examined. The current technology module is based on the 1000 C solid oxide electrolyzer cell and the alkaline fuel cell. The Future Technology system examines benefits involved with developing a 1800K electrolyzer operating with an advanced fuel cell.

  16. Disparate effects of constant and annually-cycling daylength and water temperature on reproductive maturation of striped bass (Morone saxatilis)

    USGS Publications Warehouse

    Clark, R.W.; Henderson-Arzapalo, A.; Sullivan, C.V.

    2005-01-01

    Adult striped bass (Morone saxatilis) were exposed to various combinations of constant or anually-cycling daylength and water temperature. Constant conditions (15 h days, 18??C) were those normally experienced at spawning and cycling conditions simulated natural changes at Chesapeake Bay latitude. Females exposed to constant long (15 h) days and cycling water temperature (TEMPERATURE group) had blood plasma levels of sex steroids (testosterone [T] and estradiol-17?? [E2]) and vitellogenin (Vg), and profiles of oocyte growth, that were nearly identical to those of females held under a natural photothermal cycle (CONTROL group). Several fish from these two groups were induced to spawn fertile eggs. Females constantly exposed to warm water (18??C), with or without a natural photoperiod cycle (PHOTOPERIOD and STATIC groups, respectively), had diminished circulating levels of gonadal steroid hormones and Vg, impaired deposition of yolk granules in their ooplasm, and decreased oocyte growth, and they underwent premature ovarian atresia. Males exposed to cycling water temperature (CONTROL and TEMPERATURE groups) spermiated synchronously during the natural breeding season, at which time they also had had high plasma androgen (T and 11-ketotestosterone [11-KT]) levels. The timing of spermiation was highly asynchronous among males in groups of fish held constantly at 18??C (STATIC and PHOTOPERIOD groups) and this asynchrony was associated with diminished plasma androgen levels. Termination of spermiation by males exposed to cycling water temperature coincided with a sharp decline in levels of plasma androgens about a month after water temperature rose above 18??C. In contrast, most males held constantly at 18??C sustained intermediate levels of plasma androgens and spermiated until the end of the study in late July. The annual cycle of water temperature clearly plays a prominent role in the initiation, maintenance, and termination of the striped bass reproductive cycle. In

  17. High-cycle fatigue behavior of Ti-5Al-2.5Sn ELI alloy forging at low temperatures

    SciTech Connect

    Ono, Yoshinori; Yuri, Tetsumi; Ogata, Toshio; Demura, Masahiko; Matsuoka, Saburo; Sunakawa, Hideo

    2014-01-27

    High-cycle fatigue properties of Ti-5Al-2.5Sn Extra Low Interstitial (ELI) alloy forging were investigated at low temperatures. The high-cycle fatigue strength at low temperatures of this alloy was relatively low compared with that at ambient temperature. The crystallographic orientation of a facet formed at a fatigue crack initiation site was determined by electron backscatter diffraction (EBSD) method in scanning electron microscope (SEM) to understand the fatigue crack initiation mechanism and discuss on the low fatigue strength at low temperature. Furthermore, in terms of the practical use of this alloy, the effect of the stress ratio (or mean stress) on the high-cycle fatigue properties was evaluated using the modified Goodman diagram.

  18. High-cycle fatigue behavior of Ti-5Al-2.5Sn ELI alloy forging at low temperatures

    NASA Astrophysics Data System (ADS)

    Ono, Yoshinori; Yuri, Tetsumi; Ogata, Toshio; Demura, Masahiko; Matsuoka, Saburo; Sunakawa, Hideo

    2014-01-01

    High-cycle fatigue properties of Ti-5Al-2.5Sn Extra Low Interstitial (ELI) alloy forging were investigated at low temperatures. The high-cycle fatigue strength at low temperatures of this alloy was relatively low compared with that at ambient temperature. The crystallographic orientation of a facet formed at a fatigue crack initiation site was determined by electron backscatter diffraction (EBSD) method in scanning electron microscope (SEM) to understand the fatigue crack initiation mechanism and discuss on the low fatigue strength at low temperature. Furthermore, in terms of the practical use of this alloy, the effect of the stress ratio (or mean stress) on the high-cycle fatigue properties was evaluated using the modified Goodman diagram.

  19. A Finite Element Model Of Self-Resonating Bimorph Microcantilever For Fast Temperature Cycling In A Pyroelectric Energy Harvester

    SciTech Connect

    Mostafa, Salwa; Lavrik, Nickolay V; Bannuru, Thirumalesh; Rajic, Slobodan; Islam, Syed K; Datskos, Panos G; Hunter, Scott Robert

    2011-01-01

    A self resonating bimorph cantilever structure for fast temperature cycling in a pyroelectric energy harvester has been modeled using a finite element method. The effect of constituting material properties and system parameters on the frequency and magnitude of temperature cycling and the efficiency of energy recycling using the proposed structure has been investigated. Results show that thermal contact conductance and heat source temperature play a key role in dominating the cycling frequency and efficiency of energy recycling. An optimal solution for the most efficient energy scavenging process has been sought by studying the performance trend with different variable parameters such as thermal contact conductance, heat source temperature, device aspect ratio and constituent materials of varying thermal conductivity and expansion coefficients.

  20. Dynamics and excess temperature of a plume throughout its life cycle

    NASA Astrophysics Data System (ADS)

    Cagney, N.; Lithgow-Bertelloni, C.

    2016-03-01

    Measurements of the velocity field associated with plumes rising through a viscous fluid are performed using stereoscopic Particle-Image Velocimetry in the Rayleigh number range 4.4 × 105 - 6.4 × 105. The experimental model is analogous to a mantle plume rising from the core-mantle boundary to the base of the lithosphere. The behaviour of the plume is studied throughout its life cycle, which is broken up into four stages; the Formation Stage, when the plume forms; the Rising Stage, when the plume rises through the fluid; the Spreading Stage, when the plume reaches the surface and spreads; and finally the Declining Stage, when the heat source has been removed and the plume weakens. The latter three stages are examined in terms of the Finite-Time Lyapunov Exponent fields and the advection of passive tracers throughout the flow. The temperature at the heater and near the fluid surface are measured using thermocouples to infer how the presence of a mantle plume would produce excess temperature near the lithosphere throughout the various stages of its life cycle. In all experiments a time lag is observed between the removal of the heat source and the decline in the excess temperature near the surface, which is proportional to the rise time. A simple analytical model is presented, which suggests that under mantle conditions (i.e. negligible thermal diffusion), the relationship between the time lag and the rise time is robust and independent of the Rayleigh number; however, the constant of proportionality is closer to unity in the absence of diffusion. Once the heat source is removed, the excess temperature near the surface declines exponentially at a rate that is inversely proportional to the rise time. The implications of this result are discussed in terms of the decline in volcanism in the Louisville hotspot chain over the past 20 Ma. The rise velocity of material in the plume is examined; the rise velocity is found to vary significantly with the plume height in a